MDS PREP
What is the prevalence of Huntington's disease in the general population?
1) 1/1000
2) 1/10,000
3) 1/100,000
4) 1/1,000,000
Huntington's disease has a prevalence of approximately 10 per 100,000 people in the general population. It is more common in certain ethnic groups, particularly those of Western European descent.
What is the role of tissue plasminogen activator (tPA) in the treatment of pulmonary embolism?
1) Prevents thrombus formation
2) Dissolves existing thrombi
3) Inhibits platelet aggregation
4) Enhances fibrinolysis
tPA is a thrombolytic agent used to dissolve blood clots. In the treatment of pulmonary embolism, it is administered to break down the clot in the pulmonary artery, thereby improving blood flow and reducing the risk of complications.
What is the primary function of the aortic valve?
(1) To prevent backflow of blood from the aorta into the left ventricle during diastole
(2) To prevent backflow of blood from the pulmonary artery into the right ventricle during diastole
(3) To prevent backflow of blood from the pulmonary vein into the left atrium during systole
(4) To prevent backflow of blood from the left ventricle into the left atrium during systole
The aortic valve is located between the left ventricle and the aorta and is responsible for preventing the backflow of blood into the left ventricle during systole, ensuring that blood is efficiently pumped out of the heart into the systemic circulation.
What is the typical age of onset for Huntington's disease?
(1) Childhood
(2) Fourth or fifth decade
(3) Seventh or eighth decade
(4) Second or third decade
Huntington's disease typically begins in the fourth or fifth decade of life. It is an autosomal dominant disorder that affects both men and women, and the symptoms include chorea, behavioral disturbances, and cognitive decline. While there is a wide range in age of onset, the average age of symptom manifestation is around 30 to 50 years.
In Cushing's syndrome, which hormone is responsible for the characteristic symptoms?
1) Cortisol
2) Thyroid hormones
3) Growth hormone
4) Insulin
Cushing's syndrome is caused by prolonged exposure to high levels of cortisol, a hormone produced by the adrenal glands. Cortisol excess leads to symptoms such as moon facies, buffalo hump, truncal obesity, purple striae, and proximal muscle weakness, among others.
What is the primary mechanism of action of amphotericin B in treating systemic fungal infections?
(1) Inhibition of fungal cell wall synthesis
(2) Inhibition of fungal DNA replication
(3) Inhibition of fungal protein synthesis
(4) Alteration of fungal membrane potential
Amphotericin B is an antifungal agent that works primarily by binding to ergosterol in the fungal cell membrane, leading to increased permeability and cell death. It is effective against a wide range of fungi and is often used to treat severe systemic infections.
How is chronic hepatitis typically defined?
(1) Asymptomatic with biochemical evidence of liver disease for less than 6 months
(2) Asymptomatic with histologically documented inflammation for less than 6 months
(3) Asymptomatic with serological evidence of hepatic disease for less than 6 months
(4) Asymptomatic with biochemical or serological evidence of liver disease for more than 6 months
Chronic hepatitis is characterized by the persistent presence of liver inflammation and damage, typically lasting for more than 6 months. It can be caused by various factors, including viral infections, alcohol abuse, autoimmune diseases, and metabolic disorders. The diagnosis is often made based on a combination of clinical symptoms, laboratory tests, and liver biopsy findings.
What is the genetic pattern of inheritance for Huntington's disease?
(1) Autosomal recessive
(2) Autosomal dominant
(3) X-linked recessive
(4) X-linked dominant
Huntington's disease is an autosomal dominant disorder. This means that a single copy of the defective gene, inherited from either parent, is sufficient to cause the disease. Each offspring of an affected individual has a 50% chance of inheriting the gene and developing the disease.