A 45 year old male died from disseminated tuberculosis. On autopsy the symptoms of tuberculosis were confirmed by both microscopical and histological analyses. What kind of hypersensitivity reaction underlies the process of granuloma development?
- A. Delayed
- B. Antibody-dependent cytotoxicity
- C. Complement-dependent cytotoxicity
- D. Anaphylactic
Correct Answer: A
Rationale: The correct answer is A: Delayed hypersensitivity reaction. In granuloma development in tuberculosis, macrophages present antigen to T cells, leading to a delayed hypersensitivity reaction. This triggers the recruitment of more macrophages and formation of granulomas. Antibody-dependent cytotoxicity (B) and complement-dependent cytotoxicity (C) involve antibodies and complement proteins in immediate hypersensitivity reactions, which are not the primary mechanisms in tuberculosis. Anaphylactic reaction (D) is an acute systemic allergic reaction mediated by IgE antibodies, not relevant to granuloma formation in tuberculosis.
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What reaction is catalyzed by a beta-lactamase enzyme
- A. the final cross-linking reaction to form the bacterial cell wall
- B. the biosynthesis of the penicillin structure from the amino acid valine and cysteine
- C. the hydrolysis of the four-membered ring present in penicillin
- D. the hydrolysis of the acyl side chain from penicillin structures
Correct Answer: C
Rationale: The correct answer is C: the hydrolysis of the four-membered ring present in penicillin. Beta-lactamase enzyme catalyzes the hydrolysis of the four-membered beta-lactam ring present in penicillin, rendering the antibiotic ineffective against bacterial cell walls. This enzyme breaks the bond in the beta-lactam ring, thus inactivating the antibiotic.
Incorrect choices:
A: the final cross-linking reaction to form the bacterial cell wall - This is incorrect as beta-lactamase does not participate in the formation of bacterial cell walls.
B: the biosynthesis of the penicillin structure from the amino acid valine and cysteine - This is incorrect as beta-lactamase is not involved in the biosynthesis of penicillin.
D: the hydrolysis of the acyl side chain from penicillin structures - This is incorrect as beta-lactamase specifically targets the beta-lactam ring, not the
A 28-year-old patient was hospitalized with preliminary diagnosis "influenza". Roseolous-petechial rash appeared on the 5th day of disease on the trunk. The temperature is 41oC. Hyperemia of face, reddening of scleras, tremor of tongue, tachycardia, splenomegaly are present. What is the most likely diagnosis?
- A. Epidemic typhus
- B. Measles
- C. Alcohol delirium
- D. Leptospirosis
Correct Answer: A
Rationale: The most likely diagnosis is Epidemic typhus (Choice A) based on the symptoms described. The presence of roseolous-petechial rash, high fever (41oC), hyperemia of face, reddening of scleras, tremor of the tongue, tachycardia, and splenomegaly are classic signs of epidemic typhus. The rash typically appears around the 5th day of the disease.
Summary:
- B: Measles typically presents with a maculopapular rash starting on the face and spreading downward. It doesn't usually present with tremor of the tongue or splenomegaly.
- C: Alcohol delirium is characterized by confusion, disorientation, and hallucinations due to alcohol consumption. It doesn't match the symptoms described.
- D: Leptospirosis presents with fever, muscle pain, and conjunctival suffusion. It doesn't typically present with the specific rash and trem
A lymph node punctate of a patient with suspected protozoa disease was examined. Examination of the stained specimen (Romanovsky's stain) revealed some crescent bodies with pointed end, blue cytoplasm and red nucleus. What protozoan were revealed in the smears?
- A. Toxoplasmas
- B. Malarial plasmodiums
- C. Dermotropic leishmania
- D. Viscerotropic leishmania
Correct Answer: B
Rationale: The correct answer is B: Malarial plasmodiums. The description of crescent bodies with a pointed end, blue cytoplasm, and red nucleus corresponds to the characteristics of Plasmodium species seen in Romanovsky's stain. Plasmodium species are known to cause malaria and have distinct features like the ones described.
Incorrect choices:
A: Toxoplasmas - Toxoplasma gondii typically appear as tachyzoites or bradyzoites under staining, not crescent bodies.
C: Dermotropic leishmania - Leishmania species appear as amastigotes in tissue smears, not crescent bodies.
D: Viscerotropic leishmania - Similar to choice C, Leishmania species do not typically present as crescent bodies in stained specimens.
For tuberculosis prevention the newborns got an injection of a vaccine. What vaccine was used?
- A. BCG
- B. Mantoux
- C. DTaP vaccine
- D. Anatoxin
Correct Answer: A
Rationale: The correct answer is A: BCG. BCG vaccine is commonly used for tuberculosis prevention because it provides immunity against Mycobacterium tuberculosis. Mantoux is a test, not a vaccine. DTaP vaccine is for diphtheria, tetanus, and pertussis, not tuberculosis. Anatoxin is a type of toxoid vaccine, not used for tuberculosis prevention. BCG vaccine has been shown to be effective in preventing severe forms of tuberculosis in infants, making it the appropriate choice in this scenario.
Name the halogen-containing antiseptic with fungicidal properties, which is used to treat dermatomycosis:
- A. Iodine solution
- B. Formalin solution
- C. Methylene blue
- D. Brilliant green
Correct Answer: A
Rationale: Rationale:
1. Iodine solution contains iodine, a halogen with antiseptic properties.
2. Iodine is effective against fungi, making it suitable for treating dermatomycosis.
3. Iodine solution is commonly used in dermatology for its fungicidal properties.
4. Formalin, methylene blue, and brilliant green do not contain halogens or have fungicidal properties.
Summary:
- Formalin is a disinfectant, not an antiseptic for dermatomycosis.
- Methylene blue is an antifungal dye, not used as an antiseptic.
- Brilliant green is an antiseptic, but does not contain halogens or have fungicidal properties.