Nokea
Which of the following investigations is the gold standard for diagnosing acromegaly?
- A. Serum IGF1 measurement
- B. Growth hormone releasing hormone measurement
- C. Oral glucose tolerance test + Growth hormone measurement
- D. Growth hormone measurement
Correct Answer: C
Rationale: The gold standard for diagnosing acromegaly is the oral glucose tolerance test (OGTT) along with growth hormone (GH) measurement. During this test, the patient is given a glucose solution to drink, and then blood samples are taken to measure GH levels at specific time intervals. In a person without acromegaly, glucose ingestion would typically suppress GH levels. However, in individuals with acromegaly, GH levels remain elevated even after glucose administration due to the inability of glucose to inhibit GH release from the tumor.
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Oxytocin:
- A. is bound to neurophysin in plasma.
- B. inhibits production of milk.
- C. inhibits myometrial contraction.
- D. inhibits sperm swimming on the gonad.
Correct Answer: A
Rationale: Oxytocin is a hormone produced by the hypothalamus and released by the pituitary gland. In the bloodstream, oxytocin is mostly bound to a carrier protein called neurophysin. This binding helps to protect oxytocin from being degraded too quickly in the bloodstream, thus allowing it to exert its effects on target tissues such as the uterus and mammary glands. Oxytocin plays important roles in stimulating uterine contractions during labor, facilitating milk letdown during breastfeeding, and promoting social bonding and emotional connections.
Karyotype 47, XYY is:
- A. True hermaphroditism
- B. Supermale
- C. Klinefelter's syndrome
- D. Gonadal dysgenesis
Correct Answer: B
Rationale: Karyotype 47, XYY refers to the presence of an extra Y chromosome in males. This condition is known as XYY syndrome, also called Jacob's syndrome. Individuals with XYY syndrome are typically phenotypically male but may have some associated physical and behavioral characteristics. These individuals are often referred to as "supermales" due to the presence of the extra Y chromosome. This is different from true hermaphroditism, Klinefelter's syndrome, and gonadal dysgenesis, which have distinct chromosomal patterns and manifestations.
All the following drugs are associated with an increased risk of osteoporosis in adults except:
- A. Cyclosporine
- B. Heparin
- C. Prednisone
- D. Ranitidine
Correct Answer: D
Rationale: Ranitidine is not associated with an increased risk of osteoporosis in adults. It is a histamine-2 blocker commonly used to reduce stomach acid production and treat conditions such as ulcers and gastroesophageal reflux disease. On the other hand, the other options listed are known to increase the risk of osteoporosis:
Obesity is associated with an increased incidence of all the following except
- A. Diabetes mellitus
- B. Cancer
- C. Hypertension
- D. Chronic obstructive lung disease
Correct Answer: D
Rationale: Obesity is associated with an increased risk of developing various health conditions, including diabetes mellitus, cancer, and hypertension. However, chronic obstructive lung disease (COPD) is not directly linked to obesity. COPD is primarily caused by exposure to harmful particles or gases, most commonly from cigarette smoke. While obesity can impact lung function and worsen symptoms in individuals with COPD, it is not a direct cause of the condition. Therefore, the correct answer is D, chronic obstructive lung disease.
Which of the following lung cancers is most commonly associated with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH)?
- A. Squamous cell carcinoma
- B. Small cell (oat cell) carcinoma
- C. Large cell carcinoma
- D. Adenocarcinoma
Correct Answer: B
Rationale: Small cell (oat cell) carcinoma of the lung is most commonly associated with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). This paraneoplastic syndrome occurs in patients with small cell lung cancer due to the production of antidiuretic hormone (ADH) by the tumor cells. The excessive release of ADH leads to water retention and dilutional hyponatremia, causing symptoms such as nausea, confusion, seizures, and potentially life-threatening complications. Other types of lung cancer, such as squamous cell carcinoma, large cell carcinoma, and adenocarcinoma, are less commonly associated with SIADH.