Explanation:

This acute rejection is recognised and due to anti-IgG antibodies to the HLA incompatible tissues with primary activation of T cells. The acute response is treated with immunosuppresants.

Explanation:

Explanation:

Oncogenes are endogenous human deoxyribonucleic acid (DNA) sequences that arise from normal genes called proto-oncogenes. Proto-oncogenes are normally expressed in many cells, particularly during fetal development, and are thought to play an important regulatory role in cell growth and development. Alterations in the proto-oncogene can activate an oncogene, which produces unregulated gene activity, contributing directly to tumourogenesis. Oncogene alterations are important causes of:

• Rhabdomyosarcomas (ras oncogene)

• Burkitt´s lymphoma (C-myc is translocated intact from its normal position on chromosome 8 to chromosome 14)

• Neuroblastoma (N-myc proto-oncogene is seen in a proportion of patients with poor prognosis).

They should be contrasted with tumour suppressor genes. In this situation, the genes normally down regulate cell growth, and require inactivation to allow malignant growth. Examples include retinoblastoma.

Explanation:

The aetiology of gout can broadly be divided into cases where there is underexcretion of urate via the kidney (90%) or endogenous overproduction of uric acid (10%) although in practical terms the distinction is rarely made as it allopurinol is the mainstay of long- term treatment (not during the acute attack!) in both groups. In a 73- year-old man it is almost certainly reduced renal excretion due to deteriorating renal function and possibly diuretic use. Excessive dietary intake of purines is unlikely to be the main cause in this case

Explanation:

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 EL syndrome is rare and, unlike myasthenia gravis which affects mostly women, primarily affects men over the age of 40 and is associated with usually and underlying bronchial neoplasm. Strength usually is reduced in proximal muscles of the legs and arms, producing a waddling gait and difficulty elevated the arms. The disorder is associated with the presence of antibodies against the Voltage dependent Calcium channels.

Explanation:

Iron overload, not deficiency, can exacerbate alcoholic liver disease by increasing lipid peroxidation. Acetaminophen, isoniazid, anesthetic agents, and carbon tetrachloride can all exacerbate liver disease by interfering with the microsomal enzyme system and causing glutathione depletion. The survival rate is lower and the incidence of hepatocellular carcinoma is higher in patients with hepatitis C or B viremia and alcoholic liver disease. Fulminant hepatic failure can occur in acute infection and end-stage cirrhosis. Helicobacter pylori infection potentially contributes to hepatic encephalopathy because of its high urease activity; which promotes the conversion of urea to ammonia, one of the precipitating factors of hepatic coma. Vitamin A depletion, retinoid depletion, and thiamine, folate and ascorbic acid depletion can all exacerbate alcoholic liver disease. Glutathione and alpha-tocopherol are antioxidants which, when depleted, can cause an alteration in the hepatocyte, leading to accelerated liver failure.

Explanation:

Eikenella corrodens is the other member of the HACEK group (the “E” in HACEK), which comprises a group of fastidious Gram- negative bacteria. Enterococcus is not part of the group. HACEK organisms can cause a subacute bacterial endocarditis. IV drug abusers and individuals with prosthetic valves are more at risk for HACEK infection

Explanation:

The most aggressive breast cancers, i.e., those most likely to metastasize, tend to be estrogen receptor negative. Angiogenesis, the development of new blood vessels in a tumor which facilitate the ability of the cancer cells to metastasize, is most prominent in aggressive breast cancers. The finding of more than ten tumor positive lymph nodes at the time of axillary chain dissection is associated with breast cancers more likely to metastasize. Inflammation in the tumor carries a poor prognosis for tumor spread, i.e., the tumor grows rapidly. The larger the primary tumor, the more likely it is to metastasize.

Explanation:

HIV/AIDS is spreading most rapidly in Asia.

Explanation:

Bronchial cysts are not associated with polycystic kidney disease. Patients with polycystic kidney disease can have associated hepatic cysts. They also are at risk for chronic renal insufficiency, hypertension, and renal failure, due to progressive renal damage.

Explanation:

Infection with Calymmatobacterium granulomatis causes painful beefy red granulomatous lesions. It is a sexually transmitted disease. H. ducreyi causes chancroid, which presents with a painful ulcer and secondary inguinal adenopathy. Treponema pallidum causes syphilis. Gardenerella spp. is a factor in bacterial vaginosis. Chlamydia trachomatis subtypes L1-L3 may cause lymphogranuloma venereum, which may produce a vesicular lesion followed by inguinal lymphadenitis and, eventually bubo inguinale.

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:

Alcoholics often develop folate deficiency, and this is most commonly manifested by a stocking glove peripheral neuropathy Mononeuritis multiplex is an inflammatory condition of nerves, often associated with an autoimmune process. Vasculitis can produce inflammation of the vasa nervorum, resulting in isolated areas of neuritis. Iron deficiency is not responsible for paresthesias. Diabetes can cause a similar peripheral neuropathy, but would not be the most likely etiology for this patient´s symptoms.

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.