Explanation:

Plasmids are circular molecules of bacterial deoxyribonucleic acid (DNA) separate from the bacterial chromosome. They are usually:

• small
• consisting of a few thousand base pairs
• carry one or a few genes, and
• have a single origin of replication.

Genes on plasmids with multiple copies are usually expressed at higher levels.
In nature these genes often encode for proteins such as those needed for bacterial resistance.
Plasmids can be used to clone genes by splicing a particular gene into a plasmid and then allowing the bacteria to multiply-this is then called recombinant plasmid DNA

Explanation:

Turner´s syndrome is caused by a chromosomal abnormality that results in a 45, XO karyotype, producing loss of ovaries and somatic abnormalities. Klinefelter´s syndrome has a Karyotype of 47, XXY and results in congenital testicular damage. Testicular feminization syndrome is a syndrome of feminization due to androgen insensitivity, and the karyotype is a normal 46, XY. Down´s syndrome is caused by a trisomy of chromosome 21.

Explanation:

This patient´s condition is a classic third-trimester complication referred to as toxemia of pregnancy or preeclampsia. Preeclampsia is defined as “sustained elevation of HP >140/90 after 20 weeks of pregnancy with proteinuria.” It occurs in 6% of all pregnancies but is more frequent in primiparas. Although the pathogenesis is still unclear, the first event appears to be placental ischemia, probably due to abnormalities in the trophoblast and alterations in the maturation of placental vessels. The trophoblast of invading placental vessels fails to acquire the characteristics of normal endothelial cells, with subsequent alterations in blood flow. Placental ischemia then triggers the release of thromboplastic substances, increases renin synthesis, and reduces prostaglandin E levels.
Chorioamnionitis (choice A) is an infection of chorioamnionic membranes due to bacteria that ascend through the vaginal canal. This is an important cause of spontaneous abortion in the second and third trimesters but plays no role in the pathogenesis of toxemia of pregnancy, The release of thromboplastic substances may cause disseminated intravascular coagulation (DIC) (choice B)
Increased renin and reduced prostaglandin E mediate increased sensitivity to angiotensin, leading to maternal hypertension (choice C)
Ischemic damage to maternal organs, including brain, liver, and kidneys (choice D) results from thrombotic occlusion of arterioles and capillaries as a consequence of DIC.
Overall, the clinical picture of toxemia is due to DIC mediated ischemic damage to brain (changes in mental status and convulsions), liver (elevated liver enzymes), and kidneys (proteinuria, leading to peripheral edema).A manifestation of toxemia is HFLLP syndrome which stands for hemolysis, elevated liver enzymes, and low platelets.

Explanation:

Virulence factors are more common in uncomplicated infections than in complicated ones, presumably because host resistance must be overcome in the former. Strains of E. coli are more likely to contain K antigens (capsular polysaccharides), which resist phagocytosis. Both E. coli and Proteus contain fimbriae, which mediate their attachment to specific receptors on epithelial cells. Production of hemolysin also increases virulence. Urease producing bacteria, such as Proteus, Providencia, and Corynebacterium D2, are especially virulent because they produce ammonia, which is toxic to the kidney.

Explanation:

Rubella infects a fetus via uteroplacental transfer. Group B Streptococci, Chlamydia, Gonococci, and Mycoplasma all can infect the infant as it passes through the birth canal.

Explanation:

Goodpasture´s syndrome affects the lungs and the kidneys. It causes both pulmonary hemorrhage and acute glomerulonephritis because the body recognizes a self antigen (in this case, a basement membrane protein) which elicits an immune response. The other organs are not typically involved.

Explanation:

Serum sickness is due to circulating antibody-antigen complexes (type III). Graves´ disease is due to stimulating antibody (type V). The most severe variety of type I reaction is anaphylaxis, with angio- oedema an intermediate reaction associated with wheeze and swelling of the lips and severe urticaria. These reactions are mediated by histamine 1 receptor stimulation. Congenital C1 inhibitor deficiency is also caused by hereditary angio- oedema. Deficiencies in Clr, s, and 2-4 result in vasculitides; while deficiencies in C2, 3 and 5-8 are associated with an increased risk of septicaemia.

Explanation:

The tuberculin skin test is an example of type IV hypersensitivity, or delayed type hypersensitivity (DTH) reaction. This reaction develops when primed Th l cells encounter their specific antigen. An inflammatory response evolves over 24-72 hours.
In the tuberculin skin test, the injected antigen is protein derived from M. tuberculosis. Th1 cells recognise peptide bound to MHC on APCs and are activated to secrete proinflammatory cytokines including IL 2, IFN-gamma, TNF, chemokines and GM-CSF. There is recruitment of inflammatory cells, predominantly macrophages, to the site of antigen deposition, with activation of phagocytes.
Some cytokines (TNF) as well as macrophage derived lytic enzymes cause local tissue destruction. CD8+ T-cells have also been implicated in DTH responses. The result is an indurated erythematous lesion at the site of injection which indicates previous exposure to TB.

Explanation:

Familial hypercholesterolaemia is an autosomal dominant condition manifest by increased low density lipoprotein (LDL) concentrations (not chylomicrons) due to constitutional abnormalities and reduced numbers of the LDL receptor. Hypertriglyceridaemia is not characteristic and high density lipoprotein (HDL) concentrations are usually decreased. Tendon xanthomata are characteristic and the condition is associated with a premature cardiovascular mortality.

Explanation:

The suggestion here is that the patient has myotonic dystrophy. Myotonic dystrophy is autosomal dominant and exhibits anticipation as the number of trinucleotide repeats undergo triplet expansion, resulting in the disease presenting at a younger age, or with greater disease severity along the generations.
Examples of chromosome instability syndromes are Fanconi anaemia, ataxia telangiectasia and Bloom syndrome.

Explanation:

Gardener´s syndrome or familial adenomatous polyposis is characterized by multiple small and large intestinal tumours and lipomas. Osteomata and fibromas are also seen.
It is a rare familial condition, when arising from mutations of the APC gene is inherited in an autosomal dominant fashion.
Gardener´s syndrome carries an increased risk of papillary carcinoma of the thyroid with preponderance for female patients.

Explanation:

Germline p53 mutations occur only in Li-Fraumeni syndrome, an autosomal dominant trait, which predisposes an individual to the development of cancer in their childhood

Explanation:

Dissecting aortic aneurysm usually begins by a tear of the ascending aorta, slightly above the aortic valve. Key ingredients, for dissection include arterial hypertension and medial degeneration of the artery. Otherwise healthy women in the third trimester are also at risk. Hormonal changes in pregnancy have been implicated. Congenital aortic valve anomalies and valvular aortic stenosis especially that associated with a bicuspid valve also increase risk. Turbulence past the stenotic valve increases lateral forces in the vessel wall, predisposing to dissection. Coarctation of the aorta, but not the pulmonary artery, produces proximal aortic hypertension, predisposing to dissection.

Explanation:

Sjogren´s syndrome is an autoimmune disorder characterized by xerostomia and dry eyes. None of the other choices are associated with an increased incidence of lymphoma development.

Explanation:

In general, any condition characterized by excessive estrogenic stimulation is associated with some degree of endometrial hyperplasia and increased risk of endometrial cancer. Endometrial hyperplasia is a histologic precursor of endometrial adenocarcinoma. Hyperplasia may progress to invasive adenocarcinoma through progressive degrees of cellular and architectural atypia. The grade of hyperplasia, therefore, is related to the severity of alterations of gland architecture, growth pattern, and cytologic features. The most severe changes are present in complex hyperplasia with atypia. Disorganization and crowding of glands, high mitotic activity, and nuclear atypia characterize this change. Longitudinal studies show that 25% of women with this form of hyperplasia develop adenocarcinoma. Complex hyperplasia without atypia is characterized by similar crowding of glands and epithelial cells in the absence of cellular atypia, progression to cancer occur in 5% of cases. In simple hyperplasia the glands are dilated and irregular, but cytologic atypia and mitoses are absent and transformation is rare. Chronic endometritis has no relationship with endometrial adenocarcinoma and refers to a condition of chronic inflammatory infiltration of the endometrium. A diagnosis of chronic endometritis is made only when plasma cells are found on biopsy. Lymphocytes are normally present in the endometrial mucosa. This condition is associated with pelvic inflammatory disease (PID), intrauterine contraceptive devices (IUD), and retention of gestational tissue within the uterine cavity. Squamous metaplasia is occasionally found in endometrial biopsy and results from transformation of the normal columnar epithelium into squamous epithelium. It is not associated with endometrial adenocarcinoma.

Explanation:

Patients with chronic hepatitis B infection are at increased, risk for the development of hepatomas. The other conditions are not associated with hepatitis B infection.

Explanation:

Wilms´ tumor is the most common solid renal tumor in children. Renal cell carcinoma is the most common solid tumor in adults. The other tumors are far less common.

Explanation:

Osteitis fibrosa cystica is a bone lesion specific for hyperparathyroidism

Explanation:

Chlorhexadine is an oral antimicrobial rinse which is used in the treatment of gingivitis and periodontitis. Good oral hygiene and regular cleanings are necessary to prevent plaque buildup and periodontitis. Diabetes is associated with rapid periodontal breakdown due to impaired leukocyte function, altered collagen metabolism, and microvascular changes. Phenytoin, calcium channel blockers, and cyclosporin can also cause gingival hyperplasia. Leukemic patients can present with gingival hyperplasia. Alzheimer´s disease, stroke patients, and Parkinson´s disease patients may have difficulty performing oral hygiene and are at risk for developing periodontal disease.

Explanation:

This patient´s symptoms are most consistent with fibromyalgia, as is the absence of synovitis and laboratory abnormalities. Seronegative rheumatoid arthritis, by definition, is associated with synovitis. Scleroderma would be associated with specific physical findings, such as sclerodactyly, Raynaud´s, telangiectases, etc. Chronic leukemia would be associated with abnormalities in the blood counts. Polymyalgia rheumatica is associated with an elevated sedimentation rate.

Explanation:

Women have approximately a 1 in 9 chance of developing breast cancer, even with all the advances that have been made in screening. Breast cancer risk is increased by smoking and a positive family history.

Explanation:

The bacterial analogy to the retroviral life cycle is the process of lysogeny. During lysogeny, a temperate or lysogenic bacteriophage inserts its DNA into the bacterial chromosome by site-specific recombination. Thereafter, replication of bacteriophage DNA is under the control of the replication of the cell. The four most important traits that are acquired by bacteria during lysogeny are the O antigen of Salmonella, the botulinum exotoxin, the erythrogenic exotoxins of Streptococcus pyogenes and the diphtheria toxin. The anthrax exotoxin is encoded on the plasmids of Bacillus anthracis. It is not found in the genome of a temperate phage. Endotoxin is encoded on the bacterial chromosome and not in the genome of a temperate phage. Shiga toxin is encoded on the bacterial chromosome, not in the genome of a temperate phage. Tetanus toxin is encoded on a nonconjugative plasmid, not in the genome of a temperate phage.

Explanation:

Explanation:

Severe combined immunodeficiency (SCID) is associated with deficiencies in both Band T cells due to a defect in differentiation of an early stem cell. Over 50 % of the cases are caused by a gene defect on the X chromosome, resulting in a defective IL-2 receptor. Adenosine deaminase deficiency is an autosomal recessive disease characterized by a deficiency of adenosine deaminase, which results in accumulation of metabolites that are toxic to both B and T stem cells in the bone marrow. Children with severe infections usually die within the first 2 years of life unless they receive bone-marrow transplants. A defective CD40L molecule causes hyper-IgM syndrome. This makes it impossible for B lymphocytes to receive the signal to switch isotypes, and they are therefore “stuck” making IgM alone. It is not classified as a SCID. Inability to produce MHC-II causes bare lymphocyte syndrome, which causes patients to be unable to produce CD4 cells. It results in a type of SCID since TH cells are necessary for the function of all immune responses. Nonsense mutation of rag genes results in a SCID because without the ability to perform VDJ recombinations, lymphocytes cannot express surface receptors for antigen; and in that case, lymphocyte precursors are induced to undergo apoptosis in the bone marrow. Recombination activating genes (rag genes) are responsible for the VDJ rearrangements that allow lymphocytes to create the idiotype of their antigen receptors.

Explanation:

The classic complement pathway involves C1, C4, and C2 to the point of splitting C3. C3 is then split to yield C3b and C3a. A deficiency of C4 would have no effect on any of the other answer choices listed. The complement protein C3 can be split into C3a and C3b using the alternative pathway. The additional proteins required in this pathway would be factors B and D and properdin. The C5 convertase enzyme can be formed in the alternative pathway without using C4. The C5 molecule could be split into C5a and C5b using the alternative pathway, without the involvement of C4. The membrane attack complex (C5b, C6, C7, C8, and polymers of C9) lyses the pathogenic cell. This process does not require the alternative pathway and would not require C4.

Explanation:

This patient has hereditary angioedema, which is caused by deficiency of CI esterase inhibitor. Patients experience acute episodes of localized edema and colic. Stridor may occur because of airway obstruction due to laryngeal edema, the most dreaded complication of this condition. The disease is inherited as an autosomal dominant trait, explaining this patient´s positive family history. Administration of epsilon-aminocaproate, an inhibitor of plasmin activation of Cl, reduces the frequency of the episodes. C3b inactivator inhibits enzymes of the complement system. Factor H binds to C3b and C3b-containing convertases, precluding the binding of C3b to B. This interrupts the alternative pathway. Factor H also results in the dissociation of C3b from the Bb in the C3 and C5 convertases. Carboxypeptidase is a hydrolase that removes amino acids from the free carboxyl group at the end of a polypeptide chain. Properdin functions in the alternative path-way and recognizes a large range of microorganisms. Properdin places C3b on the microbial membrane, even in the absence of a specific antibody.

Explanation:

The vast majority of cases occur in individuals younger than 30 years. Usually, the symptoms are relatively mild, and death is uncommon. Enteroviruses, arboviruses, and type 2 herpes simplex virus are the most common causes of viral meningitis. Also up to 10% of HIV patients develop an acute meningitis, typically at the time of seroconversion. Adenovirus infection is associated with upper respiratory tract infections (URIs), sinusitis, ocular disease, enteric infections, and bladder infections. It does not typically cause aseptic meningitis. Human papillomaviruses are associated with warts on the skin and genital areas. Poxviruses include the causative agents of smallpox, cowpox, and molluscum contagiosum. These agents do not typically cause meningitis. Reoviruses cause URIs, hepatitis, gastroenteritis, and encephalitis, but not meningitis.

Explanation:

Spongiosis is the name used for intercellular edema of the epidermis. Fluid accumulates between the cells, pulling them apart. However, the intercellular connections (desmosomes) remain largely intact. This produces a distinctive microscopic appearance in which each cell is surrounded by a broad white band with tiny dark cross-stripes, somewhat reminiscent of a closed zipper.
Acantholysis is the process of cell separation seen in some blistering diseases. The intercellular connections are broken in acantholysis, producing “rounded-up” cells that are dissociated from each other. Acanthosis is a marked thickening of the epidermis due to an increase in the number and size of the epithelial cells. Hyperkeratosis is an increase in the thickness of the superficial keratin layer of the epidermis. The term parakeratosis is used when nuclei are present in the normally anuclear superficial keratin layer.

Explanation:

Explanation:

The disease is adenocarcinoma of the colon. Predisposing conditions include inflammatory bowel disease (ulcerative colitis more than Crohn disease) and adenomatous polyps occurring either as an isolated finding or as part of familial syndromes including familial polyposis coli, Gardner syndrome, and Turcot syndrome. Western diets high in fat and protein and low in fiber are also thought to predispose for colon cancer. Diverticulitis (inflamed diverticula) and diverticulosis (the presence of diverticula in the colon) do not appear to predispose for colon cancer. Neither juvenile polyposis syndrome, in which the polyps consist of mucus-filled tubules, nor Peutz-Jeghers syndrome in which polyps form around an arborizing tree of connective tissue and smooth muscle, predisposes for colon cancer.

Explanation:

The clinical history and gross pathology suggest Alzheimer disease. Neurofibrillary tangles and senile plaques are found primarily in higher order association cortex. Other microscopic features of Alzheimer disease include granulovacuolar degeneration and, sometimes, Hirano bodies. Central chromatolysis is a loss of histological staining seen in lower motor neurons whose axons have been damaged, for example by injury to the ventral roots. Gliosis of the caudate nucleus is a feature of Huntington disease, and certain other degenerative diseases of the basal ganglia. Lewy bodies (eosinophilic intracytoplasmic spherules) and loss of pigmented neurons in the substantia nigra are features of Parkinson disease.

Explanation:

The infant is suffering from hereditary spherocytosis, a disease that can result from defective erythrocyte cytoskeletal proteins such as spectrin or ankyrin. Spectrin is a cytoskeletal protein in the erythrocyte that helps to maintain the biconcave shape of the cell. Defective spectrin can lead to a destabilization of this network and a tendency of the affected cells to assume a spherical shape and become osmotically fragile. Such cells often become trapped in the splenic cords, and are subsequently destroyed by phagocytes, leading to hemolytic anemia, jaundice, and splenomegaly. A common complication of this disease is bilirubin gallstones, particularly those with more severe hemolytic disease. Although spherocytosis can lead to hemolysis, the resulting anemia is distinct from aplastic anemia which occurs when the bone marrow stops producing new red blood cells, and would be accompanied by a reduced reticulocyte count. Hemorrhoids are exacerbated in patients with portal hypertension, particularly in patients with hepatic disease such as liver cirrhosis. However the jaundice in this patient results not from liver disease but from biliary obstruction, which causes gallstone formation instead.
Since the disease primarily affects red blood cells white blood cell number and function are unaffected, so immunodeficiency is an unlikely complication. Renal stones may result from some hemolytic diseases though not in hereditary spherocytosis.

Explanation:

The disease is postinfectious glomerulonephritis, which is usually related to prior sore throat or skin infection by Streptococcal species; Staphylococcus also causes some cases. The prominent deposits are also known as subepithelial humps, and consist of immunoglobulin and complement. Gram-negative rods such as Escherichia, Klebsiella and Pseudomonas have not been implicated as significant causes of postinfectious glomerulonephritis. The gram negative cocci Neisseria, especially N. meningitidis, can lead to a form of nonstreptococcal glomerulonephritis. Subepithelial deposits representing immune complex deposition are seen. This patient´s presentation, however, is much more consistent with that of streptococcal infection.

Explanation:

This patient is the classic “pink puffer” with chronic obstructive pulmonary disease (COPD). COPD is an umbrella term that refers to overlapping clinical conditions resulting from a combination of emphysema, asthma, bronchiectasis, and chronic bronchitis. If emphysema is predominant, patients with COPD have severe dyspnea (“puffers”), scanty sputum production, and nearly normal arterial pressure, and thus no cyanosis (“pink”). Loss of elastic recoil is characteristic of emphysema, which is due to destruction of alveolar walls and enlargement of airspaces distal to terminal bronchioles. Destruction of the pulmonary elastic fibers brings about increased resistance to airflow, which is reflected by a decreased FEV1. The lungs become overexpanded; while total pulmonary capacity increases, the functioning lung parenchyma decreases. Airway obstruction is prevalent in patients who have COPD with predominant chronic bronchitis, i.e.,” blue bloaters.” Decreased PaO2 manifests with cyanosis (“blue”) and bronchitis causes abundant sputum production. Pulmonary hypertension and right ventricular overload produce peripheral edema (“bloaters”). The patient in this case does not fit this description. Bronchospasm is associated with asthma, a frequent component of COPD. Attacks of asthma are due to spasm of bronchiolar smooth muscles, resulting in increased resistance to expiration. The clinical history clearly rules out bronchospasm as the fundamental mechanism of this patient´s condition. Chest wall deformity, such as severe kyphoscoliosis and obesity, and interstitial infiltration, usually due to interstitial fibrosis, are responsible for restrictive pulmonary disease. Restrictive pulmonary disease leads to decreased lung compliance and reduction in all respiratory volumes. The barrel chest deformity of this patient is a consequence, not a cause, of the underlying pathologic change, i.e., overexpansion of lungs.

Explanation:

Fibrorystic changes per se do not increase the risk of invasive cancer unless there is concomitant epithelial hyperplasia. This is defined as an increase in the number of epithelial cell layers in the terminal duct-lobular unit (TDLU). According to recommendations issued by the College of American Pathologists, patients with fibrocystic changes can be classified into three categories (1-3 below) with respect to the risk of developing invasive breast carcinoma:
1. Fibrocystic changes with no or mild epithelial hyperplasia (<4 cell layers): no increased risk (compared with the normal population)
2. Moderate or florid epithelial hyperplasia: 1.5-2 times the risk
3. Atypical ductal or lobular hyperplasia: 5 times the risk
4. In situ ductal or lobular carcinoma: 8-10 times the risk
Apocrine metaplasia, calcification, cysts, and fibrosis do not have any effect on the risk of cancer transformation, no matter how prominent or extensive these features appear. Such changes are nonetheless important in the diagnosis of fibrocystic changes. The cysts are also primarily responsible for the symptomatology, i.e., tenderness, pain, and discomfort often manifesting with a cyclical pattern. Aspiration of a large cyst may result in prompt relief of pain.

Explanation:

Prophylactic antibiotics are frequently given in both laparoscopic an open cholecystectomy. Typically broad spectrum antibiotics are administered with a consequent risk of Pseudomembranous colitis. However, it must also be remembered that Clostridium difficile may all be contracted on the wards. Bile acid diarrhoea may affect 10% of patients following cholecystectomy. Typically it is post-prandial; the bile, with no gall bladder to store it, is excreted directly into the gut.

Explanation:

Vitamin D resistant rickets is inherited in an X-linked dominant so an affected female will transmit the disease to 50% of her sons and 50% of her daughters. An affected male will transmit the condition to all of his daughters and his sons. In this case the mother is unaffected; therefore there is no risk of condition being passed to her unborn child.

Explanation:

Selenium deficiency is one of the reversible causes of dilated cardiomyopathy.

Explanation:

As both parents are carriers for the CF gene then the chances of another child being affected (homozygote) is 1 in 4 (25%).
The chances of their child being free from the CF gene is also 1 in 4 (25%) and the chances of a child being a carrier (heterozygote) is 1in 2 (50%)

Explanation:

The rotator cuff, consisting of the supraspinatus, infraspinatus, teres minor, and subscapularis (SITS) muscles, helps stabilize the humerus in the glenoid fossa of the scapula during many athletic overhead arm motions (eg, pitching, swimming, weightlifting, serving in racket sports). Disorders can involve strain, tendinitis, or a partial or complete tear.
Symptoms of bursitis include shoulder pain, especially with overhead activity, and weakness. The pain usually is worse between 80° and l20° (painful arc of motion) of shoulder abduction or flexion and is usually minimal or absent at < 80° or > 120°. Signs vary by severity. Incomplete tendon tears and tendinitis produce similar symptoms.
The supraspinatus is assessed by having the patient resist downward pressure on the arms held in forward flexion with the thumbs pointing downward (“empty can” test).
The infraspinatus and teres minor are assessed by having the patient resist external rotation pressure with the arms held at the sides with elbows flexed to 90° this position isolates rotator cuff muscle function from that of other muscles such as the deltoid. Weakness during this test suggests significant rotator cuff dysfunction (eg, a complete tear).
The subscapularis is assessed by having the patient resist internal rotation pressure or by having the patient place the back of the hand on the back and then try to lift the hand off (lift-off test).

Explanation:

Postmenopausal women are at greater risk for osteoporosis than any other group. There is a higher incidence of osteoporosis in women than in men and in white women than in African-American women. Osteoporosis is rare in adolescents of either sex or in newborns.

Explanation:

The expression of allergic diseases reflects an autosomal dominant pattern of inheritance with incomplete penetrance (A). High levels of allergen-specific IgE are produced in response to inhaled allergens. This IgE response is most probably controlled by immune-response genes located within the major histocompatability complex on chromosome 6 (B). Sensitization to an allergen is required for an IgE response to be elicited (C). Following inhalation, the allergen must be internalized by antigen-presenting cells. Following exposure to CD4+ lymphocytes, if the TH2 class recognizes the allergen, a particular repertoire of mediators is set in motion (D). After the initial allergic reaction has occurred, mast cells amplify the reaction by releasing vasoactive agents as well as cytokines, such as GM-CSF and IL-1 to IL-G (E).

Explanation:

Bence Jones proteins are immunoglobulin light chains, which are secreted by neoplastic lymphoid cells in malignant myeloma and found in the urine. They may be nephrotoxic to the kidney tubules, or their precipitation may cause tubular obstruction, leading to kidney dysfunction.

Explanation:

A common manifestation of Ehlers Danlos syndrome is joint hypermobility. Joints tend to have reduced mobility in osteoarthritis and rheumatoid arthritis, and do not have increased mobility in chondroepiphyseal dysplasia or osteogenesis imperfecta.

Explanation:

Xanthomatous lesions are not found in association with hyperthyroidism. Hyperlipoproteinemias, diabetes mellitus, hypothyroidism, and pancreatitis can all be associated with xanthomas, which are characterized by lipid rich cells.

Explanation:

In classical Turner´s syndrome, individuals have a 45-XO genotype and have abnormal sexual differentiation in utero. The other conditions do not affect intrauterine sexual differentiation

Explanation:

This is an example of desmoplasia, which is excessive fibrous tissue formation in the stroma of a tumor. The abundant fibrous tissue growth is itself, benign. Desmoplasia is usually seen with malignant neoplasmas, although there are benign processes such as surgical scars that can also constitute a desmoplastic reaction.
Anaplasia is a term used for tumors that show severe loss of cell differentiation and tissue organization anaplastic tumors typically are much more clinically aggressive than their well differentiated counterparts. Dysplasia is atypical cellular proliferation (without being so severe as to qualify for the diagnosis of cancer); an example is the epithelium seen in tubular adenomas of the colon. In contrast, carcinoma in situ is a similar change that is severe enough to be classified as cancer but is confined to the epithelium with no invasion of underlying tissue.
Carcinoma in situ can be found throughout the epithelial surfaces of the body.
Metaplasia is the replacement of one type of differentiated cell or tissue by another not normally present at that site; an example is the replacement, in smokers, of the normal, ciliated, columnar epithelium of the respiratory tract with squamous epithelium.

Explanation:

This young woman is infected with Chlamydia trachomatis. This genus of organisms is unusual in that they do not make ATP and are thus obligate intracellular parasites, and they possess a cell wall in which muramic acid is missing from the peptidoglycan. Thus they have a cell wall, but it is made of highly modified peptidoglycan (it can be called peptidoglycan at all). It has sterols in its membrane is a statement that would describe the mycoplasmas. These are the only prokaryotes that totally lack a cell wall, but instead have sterols in their membranes. It lacks a cell wall would be a statement that describes the mycoplasma. These prokaryotes are devoid of a cell wall, but have sterols in their membranes. Its cell membrane contains ergosterol would describe the fungi. This molecule is unique to fungi and is the target molecule for nystatin and the imidazoles. A cell wall containing mycolic acids describes the genus Mycobacterium. Mycolic acids are long chain fatty acids that give this group its resistance to environmental stresses and its acid fast staining characteristics.

Explanation:

This case is classic for rheumatic fever, including two of the major Jones criteria (carditis, polyarthritis) and several minor criteria (fever, arthralgia, elevated ESR, leukocytosis, C reactive protein, prolonged PR interval). Rheumatic fever is a sequela of untreated infection with group A streptococci (S. pyogenes). S. pyogenes is differentiated from the other beta hemolytic streptoccoci by its sensitivity to the antibiotic bacitracin. The catalase test is used to differentiate staphylococci from streptococci. Staphylococci are catalase positive; streptococci are catalase negative. So, S. pyogenes would be catalase negative. The coagulase test is used to differentiate Staphylococcus aureus from the other staphylococci species. S. aureus is coagulase positive; the others are negative. Sensitivity to novobiocin is used to differentiate Staphylococcus saprophyticus (resistant) from Staphylococcus epidermidis (sensitive). Sensitivity to optochin is used to differentiate Streptococcus pneumoniae (sensitive) from viridans streptococci (resistant).

Explanation:

Hfr to F- conjugation may cause the transfer of bacterial chromosomal DNA from one cell to another via cell-to-cell contact. The experimental situation described here does not •involve two cells exchanging DNA. Homologous recombination is a process by which linear DNA that has been delivered into a new cell can be successfully recombined into the chromosome and stabilized for future generations. It is an intracellular mechanism, which allows for the protection of DNA that has been donated by another cell. Although homologous recombination is a necessary final step in all mechanisms for transfer of bacterial DNA with the exception of the F+ to F-conjugative cross, it is not the means by which a virus transfers DNA from cell to cell. Site specific recombination is an intracellular process by which circles of DNA may become integrated together. It occurs during the lysogenic viral life cycle, when transposons move within bacterial cells and during the formation of the Hfr chromosome when a conjugative plasmid inserts itself into the bacterial chromosome. It is not a mechanism of transfer of DNA from one cell to another. Specialized transduction is the mechanism by which lysogenic (temperate) phages may accidentally transfer DNA from one bacterium to another. Temperate phages are viruses that integrate their genomes into the bacterial chromosome by site specific recombination and then may accidentally carry bacterial DNA to another cell if an error of excision occurs. Since the virus that was added to cultures in this question was a lytic virus, it is not capable of performing this type of transduction. Transformation is the process by which free bacterial DNA can be picked up by competent bacteria, imported, and integrated into the chromosome with homologous recombination. It does not involve a virus life cycle.

Explanation:

Explanation:

Individuals with C3 deficiency have an increased susceptibility to immune complex diseases, of which type III hypersensitivity reaction is an example of. The most important functions of C3 are to remove immune complexes from the bloodstream and enhancing opsonization. Type III hypersensitivity reaction causes immune complexes to self or foreign antigens bound to an antibody; this will activate complement, leading to tissue damage. Examples of type III hypersensitivity reactions include rheumatoid arthritis, SLE, post- Streptococcus glomerulonephritis. Contact dermatitis is a type IV hypersensitivity disease that depends on the action of TH1 cells, macrophages, and cytotoxic T lymphocytes. It does not depend on the presence of antibody and complement. Human immunodeficiency virus-1, which is the cause of acquired immunodeficiency syndrome (AIDS), is an intracellular pathogen that depends on the activation of TH1 cells and their cytokines for a protective immune response. A patient with C3 deficiency would not be expected to be any more susceptible to an intracellular pathogen, such- as this one, than the population at large would be. Measles is caused by rubeola virus, which is an intracellular pathogen and would not be affected by deficiencies in complement. Mycobacterium avium-intracellulare is an intracellular bacterium that infects phagocytic cells. It is controlled by a cell-mediated response, not a complement-mediated response.

Explanation:

It is stated that the child has been diagnosed with cystic fibrosis (CF). Patients with CF have fat malabsorption due to exocrine pancreatic insufficiency. This is why he is having the bulky, malodorous stools. The key to answering the question correctly is to realize that the bleeding diathesis that he is experiencing is secondary to malabsorption of one of the fat soluble vitamins. In vitamin K deficiency from any cause the platelets and the bleeding time are normal but the prothrombin time (PT) is abnormal as is shown in the example. The other fat soluble vitamins are A, D, and E. Patients with CF are given pancreatic enzyme supplementation as well as a fat soluble vitamin combination (ADEK). Vitamin A is a fat soluble vitamin; however, it is converted to several active forms used for the maintenance of healthy epithelium and vision. Deficiency results in night blindness corneal epithelial metaplasia, dry eyes bronchitis, pneumonia and follicular hyperkeratosis. Vitamin C, also called ascorbate, is utilized in the synthetic pathways of collagen and catecholamines and is used for the absorption of iron in the gastrointestinal tract. One also sees a bleeding diathesis with vitamin C deficiency; however, the PT is normal, the bleeding time is increased, and one sees poor wound healing, easy bruising, and gingival bleeding. Vitamin D, known as cholecalciferol, is part of calcium homeostasis. In response to hypocalcemia, it helps to normalize serum calcium levels. Vitamin D is converted to 1, 25- dihydroxycholecalciferol in the kidney, which stimulates calcium absorption in the gut, calcium reabsorption in the kidney, and calcium mobilization from bone in the presence of PTH. Deficiency causes rickets (in childhood) or osteomalacia (after epiphyseal closure). Vitamin E, also called tocopherol, is another of the fat-soluble vitamins. It is an antioxidant and is important in protecting other lipids from oxidative damage. Deficiency can lead to a hemolytic anemia, neurologic problems, and retinitis pigmentosa.

Explanation:

The woman has a urinary tract infection. Pregnancy can predispose for urinary tract infection by compressing urinary tract structures and partially impairing urinary flow through the urinary tract. The presence of white blood cell casts specifically implies renal involvement, since these form when the leukocytes are compressed together in the renal tubules. Similarly the presence of red blood cell casts in a bloody urine would indicate that at least some of the bleeding was occurring in the kidney. Infection of other sites in the urinary tract, including ureters, bladder, and urethra, does not cause cast formation. While spread of a urinary tract infection to a pregnant uterus is always of concern in a pregnant woman the presence of casts does not specifically suggest that this has occurred.

Explanation:

Endemic goiter, such as in this patient, is due to dietary iodine deficiency. This disorder is common worldwide in mountainous areas (where fish are not available). Frank symptoms of hypothyroidism may or may not be present, possibly because of the increased synthesis of the more potent triiodothyronine (T3) at the expense of thyroxine (T4). Copper deficiency can cause anemia, neutropenia, hypotonia, psychomotor retardation, osteoporosis, depigmentation of hair and glucose intolerance. Iron deficiency can cause anemia, cognitive dysfunction, impaired immunity, impaired thermoregulation, and reduced levels of physical activity. Selenium deficiency can cause congestive cardiomyopathy and skeletal muscle degeneration. Zinc deficiency causes rash and growth retardation, and impairments of immunity, wound healing, mentation, sexual function, and night vision

Explanation:

Explanation:

Type 2 diabetes is characterized by hyperglycemia and frequently, hyperinsulinemia. It is well known that eating a diet high in fat reduces the effectiveness of insulin; however the precise mechanism is not well understood. This diet causes insulin resistance, which reduces the overall effectiveness of insulin to decrease glucose levels. Therefore, glucose levels remain high, stimulating further insulin secretion (hyperinsulinemia). Over a period of several years, the insulin-producing β cells begin to tire and insulin production declines. Therefore, after several years, the pancreas of a type 2 diabetic could deteriorate to the point that insulin administration becomes necessary and the condition progresses to mimic type I diabetes. Beta-cell hyperfunction could result in hyperinsulinemia, but would lead to hypoglycemia, rather than the hyperglycemia seen in this patient. Elevated insulin levels are glucose-induced and not due to beta-cell hyperfunction alone. Increased glycogenolysis would occur during hypoglycemia and would be stimulated by glucagon. If glycogenolysis is excessive, hyperglycemia could be present, but hyperinsulinemia would not. Therefore, this answer is incorrect. Reduced somatostatin release would result in a slight elevation in insulin secretion, but would not result in the elevated levels seen in this patient. The primary regulator of insulin secretion is the blood glucose level. Insulin release is stimulated when glucose levels rise. While somatostatin release is also stimulated in response to insulin release and acts to decrease insulin secretion, a reduction in somatostatin release would not greatly elevate insulin levels. Also, if the elevation in insulin was due to a reduction in somatostatin, glucose levels would most likely be reduced rather than elevated. Type I (insulin dependent) diabetes mellitus does result in hyperglycemia, but does not result in hyperinsulinemia.

Explanation:

This question may seem a bit challenging, but you have all the information you need to answer it. The type of fetal membranes produced in identical twin pregnancies depends on the timing of the twinning process. The chorion forms before the amnion, so the possible combinations for all twin pregnancies are monoamnionic and monochorionic, diamnionic and monochorionic, and diamnionic and dichorionic (with the chorions either separate or fused). The first two possibilities are seen only in identical twins, the last one can be seen in both identical and fraternal twins. Exactly what happens depends on the precise point at which twinning occurs. Very early separation (at the two cell stage) produces completely separate membranes with duplication of both the amnion and chorion. Slightly later separation results in two amnions and fused chorions. Separation at a later stage, when the inner cell mass is present, produces twins with one chorion and two amnions. Very late separation results in one chorion and one amnion. Conjoined (Siamese) twins result from a very late twinning event, so the placenta will be monoamnionic and monochorionic. Monoamnionic and dichorionic placentas are not usually seen, as the chorion forms before the amnion.

Explanation:

The patient has an acquired arteriovenous fistula, probably caused by previous abdominal surgery. The decrease in peripheral resistance associated with an arteriovenous fistula causes an increase in cardiac output when the fistula is large (which usually requires involvement of a major artery such as the aorta, subclavian artery, femoral artery, common carotid artery, or iliac artery). The increase in cardiac output caused by the fistula is roughly equal to the blood flow through the fistula. The increase in cardiac output is associated with increases in both heart rate and stroke volume. The diastolic blood pressure falls because blood can rapidly exit the arterial system through the fistula, but mean blood pressure is maintained relatively constant because the normal long term blood pressure regulating mechanisms (e.g., renal body fluid feedback mechanism) still operate normally. The decrease in diastolic pressure with a normal or slightly increased systolic pressure causes the arterial pulse pressure to increase in arteriovenous fistula (note that pulse pressure is 80 mm Hg in this problem; normal is 40 mm Hg). The pulse pressure is decreased in cardiac tamponade, heart failure, hypovolemia, and shock

Explanation:

This child probably has autosomal dominant von Willebrand disease. von Willebrand disease (WD) is the most common hereditary coagulation abnormality described in humans, although it can also be acquired as a` result of other medical conditions. It arises from a deficiency of von Willebrand factor (vWF), a multimeric protein that is required for platelet adhesion. An abnormal vWF (which also carries factor VIII in the blood) causes a defect in the initial adhesion of normal platelets to a damaged vessel wall. Since factor VIII levels are also consequently low, the partial thromboplastin time is also prolonged. Defects in platelet adhesion are also seen in Bernard-Soulier disease. Abnormal platelet morphology is not seen in von Willebrand disease, but may be observed with infiltration of the bone marrow by tumor or fibrosis or after splenectomy. Defects in primary platelet aggregation are seen in thrombasthenia, which is caused by a deficiency or defect in the glycoprotein GpIIb-IIIa complex.
Defects in release of platelet vesicles or secondary aggregation are seen in storage pool disease and aspirin use.

Explanation:

This patient´s clinical scenario is most consistent with MEN I; or the “3 Ps”: parathyroid, pituitary, and pancreas. MEN I is an autosomal dominant genetic syndrome characterized by neoplasia of the parathyroid, pituitary, and pancreatic islet cells. Pituitary tumors occur in up to 50% of patients with MEN I, with prolactinomas being the most common. Hyperprolactinemia suppresses the release of gonadotropins and causes a decrease in testosterone levels. Hyperparathyroidism is the most common manifestation of MEN I. The patient´s combination of high calcium and low phosphate indicates hyperparathyroidism. Pancreatic islet cell neoplasia is the second most common manifestation of MEN I. Increased pancreatic islet cell hormones include pancreatic polypeptide, gastrin, insulin, vasoactive intestinal peptide (VIP), glucagon, and somatostatin. Pancreatic tumors maybe multicentric and up to 30% are malignant, with the liver being the first site of metastases. The symptoms depend on the type of hormone secreted. Elevations of gastrin are associated with Zollinger-Ellison syndrome (ZES), resulting in ulcers from increased acid production from parietal cells. The patient´s low fasting glucose suggests increased insulin levels. Elevations in vasoactive intestinal peptide result in profuse watery diarrhea.

Explanation:

The patient described is exhibiting signs of osteopetrosis, characterized by abnormally brittle bones with increased density throughout the body. In this condition, the ends of long bones also show a characteristic widening (Erlenmeyer flask deformity) on X-ray films. Deficient osteoclast activity underlies this rare hereditary disorder. In the autosomal dominant form, which this boy (and his father) presumably has, the defect is fairly mild, characterized by multiple fractures and anemia (due to filling of the medullary cavities of bone with immature bone). The autosomal recessive form is much more severe, with only a few afflicted children surviving into infancy. Deficiency of vitamin D causes rickets in children and osteomalacia in adults. Both are characterized by inadequate mineralization of an exuberant cartilage matrix. Deficient osteoblastic activity would produce decreased bone density, not increased density, as in this patient. Deficient synthesis of type I collagen underlies some forms of osteogenesis imperfecta. This disorder is characterized by multiple fractures; however, these fractures are related to the production of smaller amounts of abnormal bone, rather than too much bone, as in osteopetrosis. Hyperparathyroidism produces characteristic bone demineralization, in contrast to the diffuse, symmetric, skeletal sclerosis seen in osteopetrosis.

Explanation:

The P₅₀ is defined as the partial pressure of oxygen necessary to bind 50% of available hemoglobin. CO will decrease the P₅₀ of Hb for O₂. Another way of stating this is that CO left shifts the oxygen hemoglobin dissociation curve. CO is deadly because it not only binds hemoglobin with a greater affinity than does O₂ (240 times better), it also left-shifts the curve, thereby making it more difficult to unload 0₂ in peripheral tissues. Neither of these conditions will cause arterial hypoxemia. CO will not diminish the diffusing capacity of the lung; in fact, it is routinely used to measure diffusing capacity. The concentration of oxygen in arterial blood will be approximately the same for both cases. If anything, the concentration will be slightly greater in the patient with CO poisoning because CO left shifts the curve; therefore, the available binding sites of Hb for O₂ will be slightly more saturated. CO does not change the rate of O₂ binding to Hb. It does, however, bind to hemoglobin with 240 times the affinity of oxygen.

Explanation:

Bowen disease is one of three different clinical designations that produce the same histopathologic change of the penis, i.e., carcinoma in situ. Erythroplasia of Queyrat and bowenoid papulosis are the other two forms of carcinoma in situ of the penis. All these conditions are strongly associated with human papillomavirus (HPV), especially type 16. Carcinoma in situ refers to a malignant epithelial neoplasm confined within the basement membrane, without invasion of the underlying stroma. Once carcinoma in situ breaks through the basement membrane, invasive carcinoma is diagnosed. Both carcinoma in situ of the penis and carcinoma in situ of the cervix have a strong propensity to invade the underlying stroma and transform into invasive squamous cell carcinoma. Chronic cervicitis is a very common chronic condition characterized by lymphocytic and, to a lesser extent, neutrophilic infiltration of the cervix. Some degree of chronic cervicitis can be found in any woman. Unless associated with infectious agents, such as Chlamydia, gonococcus, Mycoplasma, or herpesvirus, chronic cervicitis does not have clinical importance and is not associated with an increased frequency of dysplasia. Mild cervical dysplasia refers to the presence of dysplasia involving the lower third of the squamous epithelium of the cervix. Most cases spontaneously regress, but some progress to more severe degrees of dysplasia and, eventually, carcinoma. Nabothian cysts derive their name from the surgeon Martin Naboth (Leipzig, 1675-1721), who first described these small, mucus containing cysts in the lower cervix. Nabothian cysts represent a normal effect of the transformation zone. After menarche, the simple columnar epithelium of the exposed endocervical epithelium is replaced by squamous epithelium advancing from the ectocervix. This process leads to obstruction of the endocervical crypts, with subsequent accumulation of mucus and formation of cystlike spaces. Nabothian cysts are therefore normal histologic features.

Explanation:

This patient has hypercalcaemia due to hyperparathyroidism. However, the intestinal absorption of calcium is facilitated by 1, 25 dihydroxy-vitamin D, which stimulates the microvillous membrane of the enterocyte to synthesise the calcium-binding carrier protein necessary for active calcium ion absorption.

Explanation:

The prevalence of coeliac disease is 1% in western societies, and is thus one of the commonest immune-mediated diseases. It arises as a result of genetic predisposition, at least 95% of patients are HLA-DQ2 or HLA-DQ8 positive, and also from the specific immune response to the alpha-gliadin component of gluten.
Cow´s milk can produce an immunologically mediated enteropathy, but the condition is rare and transient. The action of tissue transaminases on alpha-gliadin generates epitopes to CD4+ T-lymphocytes, which provoke an inflammatory response in the intestinal wall. In untreated individuals, alpha-gliadin specific CD4+ T cells can be found producing interferon-gamma in the intestinal wall.

Explanation:

All the other conditions are associated with a specific gene defect – CAH and Friedeich´s being autosomal recessive with Huntingdon being dominant. K1inefelter´s is due to a Chromosomal abnormality XXY. No specific defect has been detected thus far with ALS.

Explanation:

Myasthenia gravis is an autoimmune disorder of episodic muscle weakness and easy fatigability caused by antibody and cell-mediated destruction of acetylcholine receptors. It is more common among young women and older men but may occur at any age. Symptoms worsen with muscle activity and lessen with rest. Diagnosis is by IV edrophonium challenge, which briefly lessens the weakness. Treatment includes anticholinesterase drugs, immunosuppressants, corticosteroids, thymectomy, and plasmapheresis. Once myasthenia is diagnosed, CT or MRI of the thorax should be done to check for a thymoma. Other tests should be done to screen for n autoimmune disorders frequently associated with myasthenia gravis (eg, vitamin B12 deficiency, hyperthyroidism, RA, SLE).

Explanation:

Vitamin K deficiency primarily lengthens the PT and commonly is present with a normal PTT All the other conditions interfere with the PTT-based assessment of clotting but not with the PT-based assessments.

Explanation:

Apoptosis is a form of cell death that serves to eliminate unwanted, cells during development maintain cell numbers in intact organs or tissues, and eliminate immune cells after an immune response has faded. Apoptosis also occurs in response to noxious agents and in the aging process. In the prostate, it occurs after removal of androgenic stimulation from the testes. The process is the result of execution of an internal program mediated by the expression of a number of different genes. In the process of apoptosis, cells shrink and cytoplasmic organelles become more densely packed. Cytoplasmic blebs may form, and apoptotic bodies (membrane-bound cellular fragments) can be produced. The most characteristic feature of apoptosis is a distinctive peripheral aggregation of chromatin, sometimes accompanied by breaking up of the nucleus into several fragments. In necrosis, the chromatin may become more pale (karyolysis) or form irregular clumps, and the nucleus itself may shrink into a dense pyknotic body. Disaggregation of polyribosomes is characteristic of the initial stages of cellular injury and necrosis. Eosinophilia characterizes both apoptosis and necrosis. Inflammation is typically absent in apoptosis, in contrast to necrosis.

Explanation:

Protein C, protein S, and antithrombin III deficiencies all are associated with a prethrombotic state and have not been associated with cerebral infarctions in young adults. Of the 500,000 new strokes that occur in the U.S., about 5% are in adults below the age of 45. Mitral valve prolapse is a common source of emboli responsible for cerebral strokes in this age group. Mitral valve prolapse can contribute to stroke recurrence once an embolic event has occurred. The best method of detection is a transesophageal echocardiogram. The source of the embolism is fibrin platelet embolization. Libman Sacks endocarditis is associated with systemic lupus erythematosus. It is a verrucous endocarditis and associated with a valvulitis. Rheumatic heart disease is associated with mitral valve stenosis and subsequent atrial fibrillation which can contribute to embolization. Prosthetic valves that replace the mitral valve contribute to as many as 4% of embolic strokes per year. The risk is greater if atrial fibrillation is present.

Explanation:

Explanation:

Gastric carcinoma may metastasize to a number of places, including the left supraclavicular lymph node (Virchow´s node), an umbilical lymph node (Sister Mary Joseph´s sign), the rectal shelf (Blumer´s shelf), and the ovary (Krukenberg´s tumor). A Klatskin´s tumor is a pancreatic adenocarcinoma that arises at the confluence of the hepatic ducts.

Explanation:

Hydrocarbonaspiration causes pneumonitis, especially in children. Lipids, such as mineral oil, produce a chronic inflammatory response, especially following chronic aspiration. Aspiration of inert materials, such as water produces injury through asphyxiation. Small food particles, in the absence of gastric acid, can produce fibrotic, granulomatous pulmonary lesions. Larger food particles may cause death by asphyxiation. Surfactant creates a uniformly distributed phospholipid monolayer over the aqueous subphase, lining the alveolar surface, thereby decreasing the surface tension.

Explanation:

Explanation:

The causative organism is Neisseria gonorrhoeae, which is a sexually transmitted gram negative coccus. It is estimated that N. gonorrhoeae may express over one million variants of pili, resulting in the virtual absence of immunity to re-infection with this agent. The pili of this organism also are protective against phagocytosis and mediate attachment to the mucosal surfaces. The organism is the most common cause of septic arthritis in otherwise healthy, sexually active adults. The treatment is usually with ceftriaxone. The chlamydiae are intracellular organisms that cannot make ATP and do not usually cause septic arthritis. Having both hyphae and spores would be true of Candida, which usually causes arthritis as a rare complication of systemic candidiasis in immunocompromised patients.
Mycoplasma do not have true cell walls and do not usually cause septic arthritis.
Syphilis is caused by a spirochete that is visible only with dark field microscopy or direct fluorescent antibody. Secondary syphilis can (uncommonly) cause an acute arthritis, but the interval between acquiring the infection and developing the arthritis is usually months to years.

Explanation:

The most important chemotactic factors for neutrophils are the complement factor C5a and the interleukin-8.
The cytokines IL-1 and tumor necrosis factor have complex similar actions including stimulation of production of many acute-phase reactions, stimulation of fibroblasts, and stimulation of endothelium. Leukotrienes LTC4 and LTD4 cause increased vascular permeability. Prostaglandins PGI2 and PGD2 mediate vasodilation and pain. Thromboxane and platelet activating factor promote vasoconstriction and platelet aggregation

Explanation:

The changes described are those of apoptosis, which is a form of programmed cell death. Apoptosis can be seen in a variety of settings. In this case it is occurring in the context of graft versus-host disease, which is mediated by CD8+ and CD4+ cells. Apoptosis also occurs during embryogenesis, during hormone-dependent involution in the adult (e.g., menstruation), during rapid, proliferation of cell populations (e.g. intestinal crypt epithelia), and in the immune system (e.g. in developing thymus). It can also occur after duct obstruction in organs such as the pancreas, and during some viral diseases. The hallmark of this programmed method of cell death is the fragmentation of the cell with formation of cytoplasmic blebs and apoptotic bodies that are phagocytized by other healthy cells. Cerebral abscess formation is an example of liquefactive necrosis, usually seen in focal tissue destructive bacterial infection; a sterile liquefactive necrosis can also be observed in ischemic necrosis of the brain.
Gangrenous necrosis is a commonly used surgical term (e.g., in diabetic feet) that does not have a precise pathologic counterpart. Myocardial infarction results in coagulative necrosis, resulting in coagulated, anuclear cell “ghosts.” Pulmonary tuberculosis exemplifies caseous necrosis, showing necrotic, amorphous granular debris surrounded by a granulomatous response.

Explanation:

This man has arteriosclerotic occlusive disease. The intimal plaque of arteriosclerosis has narrowed the lumen of his arteries. The classic symptom is intermittent claudication, which is the pain that occurs in a muscle when it does not receive an adequate blood flow during exercise. Impotence is another common complaint. The arterial pulse at the ankle is decreased because the pressure pulse cannot be transmitted effectively through the narrowed arteries. This patient does not have any signs of lung hypoxia or anemia; therefore the arterial O2 content should be normal. When blood flow is decreased to the tissues, in this case the legs, the patient is still able to extract O2 from the blood vessels thus the rate of extraction from the vessels to the muscle should either slightly increase or remain the same. The peripheral vascular resistance is expected to be high in a patient with arteriosclerotic occlusive disease. There is no reason to suspect a decrease in serum lipid levels, especially in patients with known atherosclerosis. Elevated serum lipid levels can hasten the progression of arteriosclerosis.

Explanation:

This patient most likely has testicular feminization, which is androgen insensitivity due to an androgen receptor defect. These individuals are phenotypically female and may present with an inguinal hernia or primary amenorrhea. The clinical features include female external genitalia, a vaginal pouch, no uterus, feminized breasts and a paucity of axillary and pubic hair. Laboratory studies show a 46, XY karyotype and male levels of serum testosterone. These patients have a truly feminine appearance. Undescended testes are present and should be removed, usually alter puberty. Estrogen replacement therapy is usually indicated. Congenital adrenal hyperplasia (CAH) is typically caused by deficiencies of 11-beta-hydroxylase or 21-hydroxylase and is inherited as an autosomal recessive trait. Affected females who have female chromosomes have increased androgen production that leads to virilization. They have a vagina and uterus, but there is hypertrophy of the clitoris with ventral binding and fusion of the labioscrotal folds. Treatment includes the surgical correction of the external genitalia and glucocorticoids. The patient in this case is a genotypic male and a phenotypic female, which is inconsistent with CAH. Excess adrenal androgen resulting in extraglandular estrone production is likely the mechanism for polycystic ovarian disease which is characterized by anovulation, amenorrhea or oligomenorrhea, obesity, and hirsutism. There is an elevated LH level. These patients are genotypic females, unlike the patient in this case. Individuals with an imperforate hymen, which is caused by incomplete genital plate canalization typically present with primary amenorrhea, cyclic abdominal pain, and a bulging introitus. Menarche occurs at the appropriate time in these females, however the blood flow is obstructed. The treatment is a hymenotomy.

Explanation:

The patient has osteogenesis imperfecta (“brittle bone disease”), which is a genetic disease that causes very fragile bones. The type illustrated in the question stem is the severe, lethal form; milder forms also exist. The blue sclera may or may not be present. A variety of mutations appear to cause this clinical syndrome, most of which appear to affect type I collagen and the conversion of calcified cartilage to bone. The severe form is often fatal in infancy.
Marfan syndrome causes tall stature, ocular changes, and aortic dissection, and is not usually diagnosed in infancy. Hurler syndrome causes dwarfism and other skeletal changes, and is not usually diagnosed in infancy. Achondroplasia causes dwarfism. You should be aware that milder cases of osteogenesis imperfecta are sometimes misdiagnosed for years as “child abuse”, which can lead to the emotional trauma of the child being removed from the family.

Explanation:

This patient has Goodpasture syndrome, which affects both the renal and pulmonary systems. In the kidney, it causes a rapidly progressive glomerulonephritis associated with antibodies directed against a collagen component of the glomerular basement membrane (anti-GBM antibody-a classic clue to this diagnosis). These antibodies create a linear pattern on immunofluorescence. Note that they are also active against the basement membrane of respiratory alveoli, accounting for the pulmonary component of the disease. Autoimmune reactions such as those found in Goodpasture syndrome, certain drug allergies, blood transfusion reactions, and hemolytic disease of the newborn, are classified as Type II hypersensitivities (antibody-mediated cytotoxicity). IgG or IgM antibody reacts with membrane-associated antigen on the surface of cells, causing activation of the complement cascade and, ultimately, cell destruction. Type I reactions (immediate, atopic, or anaphylactic) require an initial (sensitizing) exposure to an antigen. On re-exposure to the antigen, cross-linking of IgE receptors occurs on the surface of basophils and mast cells. The mast cells then release a variety of mediators, including histamine. Clinical syndromes include asthma, atopic dermatitis, eczema, and allergic rhinitis. Hives are characteristic of Type I hypersensitivity. Type III hypersensitivity (immune complex-mediated hypersensitivity) is caused by formation of antibody antigen complexes, which are filtered from the blood and activate complement. This results in the generation of C3b, which promotes neutrophil adherence to blood vessel walls. The complexes also generate C3a and C5a (anaphylatoxins), which lead to inflammation and tissue destruction. The hallmark signs of Type III sickness, which occur 7-14 days after exposure to the offending antigen, include urticaria, angioedema, fever, chills, malaise, and glomerulonephritis. Clinical syndromes include serum sickness (e.g., penicillin, streptomycin, sulfonamide, phenylbutazone hypersensitivity) and the Arthus reaction. Immune complexes are also observed in systemic lupus erythematosus (SLE). Type III glomerulonephritis (e.g., poststreptococcal glomerulonephritis) is characterized by a “lumpy bumpy” appearance on immunofluorescence using labeled anti-body specific for immunoglobulin or complement. Type IV is also known as delayed-type hypersensitivity (DTH). Unlike the other types, which are mediated by antibody, DTH depends on T helper cells that have been sensitized to a particular antigen. T cells react with antigen in association with MHC class I gene products and release lymphokines. Examples include tuberculin skin testing and contact dermatitis (e.g., poison ivy rash).

Explanation:

There is a specific association between diabetes (particularly in brittle diabetics who may have episodes of ketoacidosis) and chronic sinusitis due to saprophytic Zygomycetes, including Mucor and Rhizopus. These fungi can spread rapidly from the sinuses to the nearby skull bones and brain, potentially causing massive tissue destruction and death. The term “rhinocerebral mucormycosis” is used in these cases. Less commonly, other sites may be involved (lung, gastrointestinal tract), depending on the port of entry. The physician should suspect mucormycosis in any patient with chronic sinusitis who appears unusually ill and does not respond to antibiotic therapy. Unfortunately, most cases are diagnosed at autopsy. Actinomyces are part of the normal flora of the mouth. Actinomycosis also occurs in humans and may affect the cervicofacial region (typically following dental procedures or maxillofacial injuries), lungs, abdomen (typically following surgery, trauma, or intestinal penetration), or pelvis (related to IUD use). There is no specific association with diabetes mellitus. Aspergillus can be present in the sinuses, and does have a somewhat increased incidence in diabetics, but is not the organism about which the physician should be most concerned. Cryptococcus is found in pigeon feces and is usually introduced into the body via the respiratory tract. It can disseminate to the meninges and other sites in immunocompromised patients (often AIDS patients). It would not be of particular concern in this patient with sinusitis. Pneumocystis carinii causes pneumonia in severely immunosuppressed patients, e.g., AIDS patients.

Explanation:

There is a specific association between diabetes (particularly in brittle diabetics who may have episodes of ketoacidosis) and chronic sinusitis due to saprophytic Zygomycetes, including Mucor and Rhizopus. These fungi can spread rapidly from the sinuses to the nearby skull bones and brain, potentially causing massive tissue destruction and death. The term “rhinocerebral mucormycosis” is used in these cases. Less commonly, other sites may be involved (lung, gastrointestinal tract), depending on the port of entry. The physician should suspect mucormycosis in any patient with chronic sinusitis who appears unusually ill and does not respond to antibiotic therapy. Unfortunately, most cases are diagnosed at autopsy. Actinomyces are part of the normal flora of the mouth. Actinomycosis also occurs in humans and may affect the cervicofacial region (typically following dental procedures or maxillofacial injuries), lungs, abdomen (typically following surgery, trauma, or intestinal penetration), or pelvis (related to IUD use). There is no specific association with diabetes mellitus. Aspergillus can be present in the sinuses, and does have a somewhat increased incidence in diabetics, but is not the organism about which the physician should be most concerned. Cryptococcus is found in pigeon feces and is usually introduced into the body via the respiratory tract. It can disseminate to the meninges and other sites in immunocompromised patients (often AIDS patients). It would not be of particular concern in this patient with sinusitis. Pneumocystis carinii causes pneumonia in severely immunosuppressed patients, e.g., AIDS patients.

Explanation:

Explanation:

This patient presents with the classic findings of granuloma inguinale (Donovanosis). The clue that he had traveled to New Guinea clinches the diagnosis. This is a chronic, sexually transmitted disease (STD) that presents with ulcerating granulomata of the genital skin and mucous membranes. On biopsy, there is granulation tissue and microabscesses with macrophages containing diagnostic Donovan bodies (small, rounded coccobacilli within cystic areas of the cytoplasm seen with Wright Giemsa stain). This disease is caused by the bacterium Calymmatobacterium donovani. Chlamydia trachomatis causes lymphogranuloma venereum, an STD that is rare in the U.S. but common in the tropics. It can present with genital or anorectal lesions or regional lymphadenopathy. Cytoplasmic inclusion bodies would be seen in epithelial cells. Haemophilus ducreyi causes chancroid, an STD that presents with a painful chancre and regional lymphadenopathy. Remember that “ducreyi” makes you “cry” (because it´s painful). Human papillomavirus comes in various strains, is associated with common warts as well as condylomata acuminate, and is a risk factor for cervical cancer in infected women and penile cancer in infected men. Neisseria gonorrhoeae causes gonorrhea. There may be purulent inflammation or abscesses.

Explanation:

Lipofuscin is a brown pigment that accumulates with aging. It is believed to be produced from the peroxidation of lipids. Lipofuscin accumulation does not necessarily impair the ability of the cell to function and can be found in the hearts and livers of healthy elderly patients. Beta-carotene is a carotenoid ingested in the diet (found in yellow vegetables such as squash, pumpkins, and carrots) and converted to vitamin A. Excessive beta-carotene can cause a benign yellow orange discoloration of the skin in a condition known as carotenemia. Bilirubin is a pigment derived from the metabolism of the heme group of hemoglobin. As hemoglobin is broken down, it first forms biliverdin, which is subsequently converted to bilirubin. Bilirubin can be conjugated (to glucuronic acid) or unconjugated. The conjugated form (also called the direct reacting portion) accumulates in biliary obstructions. The unconjugated form of bilirubin (indirect reacting) accumulates in hemolytic processes. Hemosiderin is the storage form of iron and stains blue with Prussian blue. Hemosiderin accumulation from breakdown of red cells is seen in chronic passive congestion of the lung (inside hemosiderin-laden macrophages called “heart failure cells”). Hemosiderin deposition is also seen in hemochromatosis, a disorder characterized by abnormal iron storage. Hemochromatosis is seen in patients with increased iron uptake from the gastrointestinal tract and in patients receiving repeated blood transfusion therapy. Melanin is a brown black pigment made by melanocytes in the skin. Melanin is also found in the iris, giving the eye its color. Neuromelanin is a type of melanin found in catecholamine neurons in the brain.

Explanation:

Glioblastoma multiforme (GBM) is the most common and most malignant of the primary CNS neoplasms. GBM belongs to the category of gliomas called astrocytomas which originate from neoplastic transformation of astrocytes. There is a continuum in the anaplastic features of astrocytomas from well differentiated astrocytoma, characterized by minimal atypia and mitotic activity, to GBM, characterized by a brisk mitotic rate, multifocal necrosis, and extreme nuclear pleomorphism. Since histologic atypia has been shown to correlate with biologic behavior, several grading systems have been developed to help predict the prognosis of astrocytomas. The most common of such grading systems (WHO and Saint Anne-Mayo) divide astrocytomas into four grades from grade I (benign, well-differentiated) to grade IV (malignant poorly differentiated). GBM is grade IV astrocytoma. It is associated with a poor prognosis; most patients die within approximately 12 months of diagnosis. Well-differentiated astrocytoma is basically a synonym for grade II astrocytoma, while anaplastic astrocytoma refers to grade Ill astrocytoma. Survival is better than GBM, although definitive cure is rare, even for well-differentiated astrocytomas. Meningioma is a benign tumor of meningothelial origin that grows from the dura mater, pushing, rather than infiltrating, the underlying brain. Nevertheless, meningiomas may infrequently show histologic features of malignancy and infiltrate the brain, in which case the prognosis is worse (though still better than the dreadful GBM). Oligodendroglioma arises from oligodendroglial cells and usually lacks histologic markers of malignancy (e.g., mitotic activity, nuclear atypia, and necrosis). Owing to its infiltrative pattern of growth, however, complete excision is virtually impossible (remember, there is no basement membrane or other anatomic boundary in the CNS to contain the spread of a glial neoplasm). Thus, oligodendrogliomas recur over and over following each surgical resection. After each recurrence these tumors acquire progressively increasing degrees of anaplasia, ultimately becoming similar to GBM. Survival can be very long (7-10 years), but definitive cure is exceptional

Explanation:

Somatostatin is released by the hypothalamus, pancreas, and GI mucosa. Hypothalamic somatostatin acts chi the anterior pituitary to inhibit the release of thyroid stimulating hormone (TSH) and growth hormone (GH). Pancreatic somatostatin is released from the delta cells and acts to inhibit insulin, glucagon, and gastrin release. GI derived somatostatin is secreted in response to H and acts to inhibit the release of all GI hormones and gastric H secretion. While administering somatostatin would inhibit GH secretion in this patient, it could also result in hypothyroidism. This condition is usually treated by resection of the tumor, since there is a high chance of involvement of the adjacent brain structures.
Aldosterone release would not be altered by the administration of somatostatin. Aldosterone is primarily regulated by the rennin angiotensin system. In this system, renin is released from the juxtaglomerular apparatus in the kidney and acts by cleaving angiotensinogen into angiotensin I. Angiotensin I is converted into angiotensin II in the lungs by angiotensin converting enzyme. Angiotensin II stimulates aldosterone release from the adrenal cortex, and aldosterone acts on the distal regions of the nephron to increase Na reabsorption. ADH release would not be altered by somatostatin administration, as ADH is primarily controlled by plasma osmolarity. ADH is produced by the hypothalamus and stored in the posterior pituitary. When plasma osmolarity increases, hypothalamic chemoreceptors are stimulated and ADH is released. ADH acts on the renal tubule to increase water reabsorption in the distal regions of the nephron. Cortisol is not directly affected by somatostatin but is released in response to adrenocorticotropin (ACTH) from the anterior pituitary. Corticotropin releasing hormone (CRH) is released from the hypothalamus in response to stressful stimuli and stimulates the anterior pituitary to release ACTH. The subsequent release of cortisol acts to increase glucose and free fatty acids necessary to provide energy for overcoming the stressful situation. Testosterone is also not affected by somatostatin administration. Hypothalamic luteinizing hormone releasing hormone (LHRH) acts on the anterior pituitary to stimulate the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH). LH acts on the Leydig cells of the testes to stimulate the synthesis of testosterone. Testosterone is released into circulation or diffuses into the Sertoli cells to facilitate spermatogenesis.

Explanation:

The patient is suffering from Raynaud disease. The dramatic color changes seen in this patient´s hands are thought to be the result of vasospasm. If another underlying disease or process (e.g., arteriosclerosis, scleroderma, multiple myeloma, occult carcinoma, ergotamine use, and lead poisoning) is contributing to the problem, the patient is said to have Raynaud phenomenon. If no obvious underlying disease is present (as in this patient), the term Raynaud disease is used. Atrophy of skin, subcutaneous tissue, and muscle may develop less commonly; ulcerations or gangrene may involve fingers and hands. Buerger disease usually occurs in young adult males who are heavy smokers. Polyarteritis nodosa is caused by immune complex deposition and complement activation it is associated with involvement of multiple organ systems and has a high association with hepatitis B. It is not associated with the patient´s peripheral vasospasm. Takayasu arteritis affects the aortic arch and its branches. Secondary vasculitis is excluded because the patient does not have another underlying disease.

Explanation:

The symptoms described indicate that John suffers from Duchenne muscular dystrophy (DMD), while Trevor has Becker muscular dystrophy (BMD). Both diseases are caused by mutations in the gene coding for dystrophin, a 427 kDa protein with a flexible rod like structure having globular structures at either end. Its amino terminal end binds to the actin filaments of myofibrils, while the cysteine rich carboxy terminus binds to beta dystroglycan as, well as other elements of the sarcolemmal membrane. Beta dystroglycan, in turn, anchors the entire complex to the basal lamina via laminin. In. short, dystrophin is a molecule that plays a critical role in maintaining muscle fiber integrity; when it is absent or nonfunctional the myofibril literally falls apart. DMD is caused by mutations in the dystrophin gene that significantly disrupt large segments; these mutations often are associated with frame-shift induced deletions, or with other mutations that disrupt critical structural elements, usually in the actin binding head of the molecule. BMD is generally caused by point mutations that permit residual function of the dystrophin molecule. As a result of these mutations, typically less than 5% bf normal dystrophin levels are found in DMD while some. 30-80% is retained in BMD. Options B, C, D, and E are not correct since mutation in genes coding for laminin or emerin do not cause DMD or BMD. However, both of these proteins are essential for the structural and functional integrity of muscle; and there is another form of MD that is associated with their deficiencies. Deficiencies of a form of laminin (laminin NC) cause X linked. Emery Dreifuss Muscular Dystrophy (EDMD) and an emerin deficiency causes the autosomal dominant form of EDMD. The two forms are clinically indistinguishable and are characterized by slowly progressive muscle weakness and wasting starting with a scapulohumeroperoneal distribution, which clearly distinguishes it from either DMD or BMD. Both emerin and laminin NC play a role in stabilizing the inner nuclear membrane and are found in particularly high concentration in skeletal and cardiac muscle. Their similar function probably accounts for the phenotypic similarity of the two forms of this disease. In both forms, the primary cause of morbidity and death is cardiac disease, which may occur anywhere from the teen years to the decade. This is an example of locus heterogeneity) i.e., similar phenotypes caused by mutations at different genetic loci.

Explanation:

 The symptoms described indicate that John suffers from Duchenne muscular dystrophy (DMD), while Trevor has Becker muscular dystrophy (BMD). Both diseases are caused by mutations in the gene coding for dystrophin, a 427 kDa protein with a flexible rod like structure having globular structures at either end. Its amino terminal end binds to the actin filaments of myofibrils, while the cysteine rich carboxy terminus binds to beta dystroglycan as, well as other elements of the sarcolemmal membrane. Beta dystroglycan, in turn, anchors the entire complex to the basal lamina via laminin. In. short, dystrophin is a molecule that plays a critical role in maintaining muscle fiber integrity; when it is absent or nonfunctional the myofibril literally falls apart. DMD is caused by mutations in the dystrophin gene that significantly disrupt large segments; these mutations often are associated with frame-shift induced deletions, or with other mutations that disrupt critical structural elements, usually in the actin binding head of the molecule. BMD is generally caused by point mutations that permit residual function of the dystrophin molecule. As a result of these mutations, typically less than 5% bf normal dystrophin levels are found in DMD while some. 30-80% is retained in BMD. Options B, C, D, and E are not correct since mutation in genes coding for laminin or emerin do not cause DMD or BMD. However, both of these proteins are essential for the structural and functional integrity of muscle; and there is another form of MD that is associated with their deficiencies. Deficiencies of a form of laminin (laminin NC) cause X linked. Emery Dreifuss Muscular Dystrophy (EDMD) and an emerin deficiency causes the autosomal dominant form of EDMD. The two forms are clinically indistinguishable and are characterized by slowly progressive muscle weakness and wasting starting with a scapulohumeroperoneal distribution, which clearly distinguishes it from either DMD or BMD. Both emerin and laminin NC play a role in stabilizing the inner nuclear membrane and are found in particularly high concentration in skeletal and cardiac muscle. Their similar function probably accounts for the phenotypic similarity of the two forms of this disease. In both forms, the primary cause of morbidity and death is cardiac disease, which may occur anywhere from the teen years to the decade. This is an example of locus heterogeneity) i.e., similar phenotypes caused by mutations at different genetic loci.

Explanation:

The alveolar PO2 is found from the alveolar gas equation:
PAO2 = PIO2 – PACO2 /R
Plo2 = .21 (P barometric – P water vapor)
P barometric = 760 mm Hg
water vapor = 47
then P102 = (.21)(713) = 149mm Hg. Therefore PAQ2 = 149-(19/1) = 130mm Hg. Thus, the alveolar-arterial difference is 130-90 =40 suggesting some underlying lung disease that is impairing oxygen uptake in the lungs.
Option A is incorrect because the decreased arterial PCO2 indicates increased alveolar ventilation. Option B is incorrect because only severe hypoxia (PO2 < 50 mm Hg) would cause alveolar ventilation to double, as it has in this patient. Primary respiratory acidosis would display increased, rather than decreased, arterial PO2. Acidosis shifts the O2 dissociation curve to the right, increasing the P50.

Explanation:

The patient´s ankle edema, shortness of breath, and relatively low blood pressure suggest the possibility of congestive heart failure which is confirmed by the cardiac enlargement and perihilar infiltrates seen on chest X-ray. The serum urea nitrogen is elevated while serum creatinine is normal, suggesting a prerenal cause for the azotemia.
Congestive heart failure with its resulting decreased blood pressure is a common cause of decreased renal perfusion leading to prerenal azotemia. Most disease processes that affect BUN and creatinine cause both to rise together. Exceptions are early congestive heart failure (in which the BUN can rise selectively) and processes that lead to increased urea synthesis, such as burns and prolonged high fever. Postrenal causes of azotemia are typically due to urinary tract obstruction distal to the kidney, and usually cause a rise in both urea and creatinine, with the rise in urea being larger than that in creatinine. Increased synthesis of urea is seen in severe burns and prolonged high fever. Renal glomerular disease severe enough to cause acute or chronic renal failure will cause urea and creatinine to rise together. Renal tubulointerstitial disease severe enough to cause renal failure will cause both urea and creatinine to rise. The creatinine may rise out of proportion to the urea, particularly in acute tubular necrosis.

Explanation:

This is a typical presentation for drug induced acute interstitial nephritis, which usually resolves when the offending drug is removed. Half of the cases progress to acute renal failure. Additional offending drugs include other penicillin derivatives, sulfonamides, and some diuretics. Acute renal tubular necrosis has been associated with exposure to aminoglycosides, amphotericin, and methoxyflurane. Crescentic glomerulonephritis is not typically associated with methicillin exposure, but rather with immunologic mechanisms or unknown causes. Minimal change disease, or lipoid nephrosis, is an important cause of the nephrotic syndrome in children and is sometimes associated with a recent respiratory infection or a vaccination. Pyelonephritis is a tubulointerstitial kidney disease caused by bacterial infection, with elements of obstruction or vesicoureteral reflux in many cases.

Explanation:

This patient has hypercalcaemia due to hyperparathyroidism. Parathormone has a number of direct effects: enhancing the release of calcium from bones by binding to osteoblasts which stimulates the formation of osteoclasts, and enhances reabsorption of calcium in distal tubules.

Explanation:

The story of galactorrhoea suggests hyperprolactinaemia and in the context of primary hyperparathyroidimsm suggests MEN type 1. MEN type 1 is an autosomal dominant condition and is associated with hyperparathyroidism, pancreatic neuroendocrine tumors and pituitary tumors.

Explanation:

Cholera toxin has two parts, A and B.
B binds while A activates G protein, which activates adenylate cyclase. Elevated cyclic adenosine monophosphate (CAMP) results in unrestricted chloride secretion from villous crypts.

Explanation:

Hepatitis is more common in alcoholics than in the general population; there is not an increased incidence of cytomegalovirus infection among alcoholics. Pneumococcal pneumonia is a common form of infection in alcoholics. DTs can be fatal. Alcoholics have a high incidence of pancreatic disease which can result in diabetes due to damage to the pancreas.

Explanation:

Substitution of a valine for a glutamic acid as the sixth amino acid of the beta globin chain is responsible for sickle cell anemia. Hemolysis can occur in patients with sickle cell anemia but does not cause it. Sickled cells are often sequestered in the spleen as a prelude to removal from the circulation, but this does not cause the disease. Neither globin chain deficiency nor heme deficiency cause this condition.