Indicate the vasoconstrictor of endogenous origin:

Correct Answer: D

Rationale: The correct answer is D: Angiotensinamide. This is because angiotensinamide is a hormone produced endogenously by the body that acts as a potent vasoconstrictor. It plays a crucial role in regulating blood pressure by constricting blood vessels. Rationale: 1. Angiotensinamide is a naturally occurring hormone in the body. 2. It acts specifically as a vasoconstrictor, narrowing blood vessels. 3. This physiological function of angiotensinamide helps regulate blood pressure. 4. In contrast, choices A, B, and C are exogenous substances with pharmacological vasoconstrictive effects, not endogenously produced hormones like angiotensinamide. Summary: A, B, and C are incorrect because they are synthetic substances with vasoconstrictive properties, whereas angiotensinamide is the correct answer as it is an endogenous vasoconstrictor hormone in the body.

Correct Answer: D

Rationale: Rationale: A: Progesterone is rapidly absorbed as it has high bioavailability. B: Progesterone is metabolized in the liver to pregnanediol and conjugated with glucuronic acid. C: Progestins and their metabolites are excreted in urine, indicating systemic circulation. Therefore, D is correct as all statements are true.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Antigens are indeed substances that trigger an immune response by stimulating antibody production. This is a fundamental concept in immunology. The other choices are incorrect because: - B: FALSE is incorrect because the statement in the question is true. - C: All is incorrect because it implies all choices are correct, which is not the case. - D: None is incorrect because there is a correct answer in this case, which is option A.

Correct Answer: D

Rationale: Rationale for Choice D (Inhibits calcineurin): 1. Tacrolimus binds to FK-binding protein, forming a complex that inhibits calcineurin. 2. Calcineurin inhibition blocks T-cell activation by preventing dephosphorylation of NFAT, hindering IL-2 production. 3. This suppresses immune response in transplant recipients. Summary: A: Inhibiting CD3 receptor is the mechanism of action of other drugs like anti-CD3 antibodies, not tacrolimus. B: Complement-mediated cytolysis is unrelated to tacrolimus. C: Substitution for deficient immunoglobulins is not the mechanism of action of tacrolimus, which targets T-cell activation.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Clavulanic acid, sulbactam, and tazobactam are all beta-lactamase inhibitors. Beta-lactamase inhibitors work by inactivating the beta-lactamase enzymes produced by bacteria, thus protecting beta-lactam antibiotics. Clavulanic acid, sulbactam, and tazobactam are commonly used in combination with beta-lactam antibiotics to enhance their efficacy. Therefore, choosing D as the correct answer is justified as all the options listed are indeed beta-lactamase inhibitors.