MDS PREP
What is the primary pathogenic mechanism of Enterotoxigenic E. coli (ETEC)?
1) Invasion of gut epithelial cells
2) Production of heat-labile toxin (LT) and heat-stable toxin (ST)
3) Induction of lipid peroxidation
4) Production of Shiga-like toxins
ETEC are the principal cause of traveler’s diarrhe1) They produce both a heat-labile toxin (LT) and a heat-stable toxin (ST) that act on the intestinal mucos1) The LT is similar to cholera toxin and increases intracellular cGMP levels, leading to enhanced fluid and electrolyte secretion into the lumen and thus diarrhe1) The ST acts by a different mechanism but also enhances fluid and electrolyte secretion.
In a patient with hyperparathyroidism, which of the following is a late and irreversible complication of hypercalcemia?
1) Renal calculi
2) Nephrogenic diabetes insipidus
3) Osteoporosis
4) Cardiac arrhythmias
While hypercalcemia can cause nephrogenic diabetes insipidus and cardiac arrhythmias, these are usually reversible with correction of calcium levels. Osteoporosis, on the other hand, is a late complication resulting from long-standing increased bone resorption and decreased bone density.
Which of the following HLA types is most strongly associated with Celiac disease?
1) HLA-DQ2
2) HLA-DQ8
3) HLA-B8
4) HLA-DR3
The strongest genetic association with Celiac disease is with the HLA-DQ2 haplotype, which is found in the majority of patients with the condition.
For study of sex chromatic body the most suitable cells for convenience
1) Blood
2) Buccal mucosa
3) Skin
4) Hair
General Medicine
Answer: 2
The sex chromatin body, also known as the Barr body, is an inactivated X chromosome found in female cells. To study the presence of Barr bodies, buccal mucosa cells are often used because they are easily accessible and can be collected non-invasively through a simple scraping of the inner cheek. Buccal epithelial cells are large and contain sufficient cytoplasm, making them suitable for microscopic examination. In contrast, blood cells (like lymphocytes) can also be used, but the collection process is more invasive and less convenient than obtaining buccal mucosa cells.
Which of the following is true regarding the Glasgow Coma Scale (GCS)?
1) It is used primarily to assess the severity of spinal injuries.
2) It assesses only motor function.
3) It is not applicable in patients with head injuries.
4) It evaluates eye opening, verbal response, and motor activity.
The Glasgow Coma Scale (GCS) is widely used to assess the severity of coma or impaired consciousness, particularly in patients with head injuries.
In Henoch-Schonlien purpura there is all except
1) Abdominal pain with proteinuria
2) Acute arthritis
3) Rectal bleeding
4) More common in adults
General Medicine
Answer: 4
Henoch-Schonlein purpura (HSP) is a small-vessel vasculitis that is more common in children than in adults. It is characterized by symptoms such as abdominal pain, arthritis, and purpura (skin rash). The other options are typical manifestations of HSP.
The primary mechanism of action of nitroglycerin in the treatment of angina pectoris is:
1) Dilatation of coronary arteries
2) Decreased cardiac contractility
3) Increased cardiac output
4) Decreased systemic vascular resistance
Nitroglycerin is a vasodilator that primarily acts by relaxing vascular smooth muscles, which leads to dilatation of coronary arteries.
Which of the following conditions is associated with a high incidence of growth hormone deficiency?
1) Down syndrome
2) Turner syndrome
3) Prader-Willi syndrome
4) Klinefelter syndrome
Turner syndrome, characterized by the partial or complete absence of one X chromosome, is associated with a high incidence of growth hormone deficiency. This leads to short stature and delayed puberty in affected females. While the other conditions listed can have various endocrine abnormalities, they are not primarily linked to growth hormone deficiency.