Nokea
Which of the following pathogenic mechanisms are not typical for autoimmune reactions?
- A. Decreased functional activity of T-suppressors
- B. Loss of tolerance for T-helpers and B-lymphocytes
- C. Ag released by normally isolated tissues
- D. Formation of CD4+ cells
Correct Answer: D
Rationale: The correct answer is D, Formation of CD4+ cells. In autoimmune reactions, CD4+ cells are actually involved in the immune response. Here's the rationale:
1. CD4+ cells are helper T cells that play a crucial role in activating other immune cells in autoimmune reactions.
2. Decreased functional activity of T-suppressors (Choice A) is typical in autoimmune reactions as it leads to unchecked immune responses.
3. Loss of tolerance for T-helpers and B-lymphocytes (Choice B) is common in autoimmune reactions, where the immune system mistakenly attacks self-cells.
4. Ag released by normally isolated tissues (Choice C) is a typical mechanism in autoimmune reactions where self-antigens trigger immune responses.
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Bacterial families have general:
- A. Morphologic features
- B. Geographic features
- C. Historical features
- D. Physiologic features
Correct Answer: A
Rationale: The correct answer is A: Morphologic features. Bacterial families are classified based on their morphologic features such as shape, size, and arrangement. This classification helps in identifying and studying different bacterial species. Choice B, Geographic features, is incorrect as bacterial classification is not based on their geographic distribution. Choice C, Historical features, is incorrect as it does not play a role in the classification of bacterial families. Choice D, Physiologic features, is also incorrect as physiological characteristics are used for further classification within bacterial families, not as a general characteristic.
In the morning a patient had nausea, abdominal discomfort, single vomiting, dry mouth. In the evening, the patient presented with the increasing general weakness, double vision, difficult swallowing of solid food. Objectively: ptosis, mydriasis, anisocoria, absence of gag and pharyngeal reflex, dry mucous membranes. The previous evening the patient had dinner with canned food and alcohol. What is the presumptive diagnosis?
- A. Botulism
- B. Poliomyelitis
- C. Food toxicoinfection
- D. Acute ischemic stroke
Correct Answer: A
Rationale: The correct answer is A: Botulism. The symptoms described, such as ptosis, mydriasis, anisocoria, dry mouth, and absent gag reflex, are classic signs of botulism. Botulism is caused by the bacterium Clostridium botulinum, commonly found in improperly preserved canned foods. The progression from gastrointestinal symptoms to neurological symptoms, like double vision and difficulty swallowing, is characteristic of botulism due to the toxin's effect on neuromuscular transmission. Poliomyelitis primarily affects the motor neurons and presents with different symptoms. Food toxicoinfection typically involves gastrointestinal symptoms and does not manifest with the neurological findings seen in this case. Acute ischemic stroke presents with sudden onset neurological deficits due to impaired blood flow to the brain, which is not consistent with the gradual progression of symptoms in this scenario.
Each of the following statements about Neisseria meningitidis is correct, EXCEPT
- A. during meningococcemia Waterhouse-Friderichsen syndrome may be present
- B. Disease is most common in children younger than age 5
- C. There is an obligatory vaccine in Bulgaria
- D. infection is transmitted by respiratory secretions in close contacts
Correct Answer: C
Rationale: The correct answer is C because there is no obligatory vaccine for Neisseria meningitidis in Bulgaria. The rationale for this is that while vaccines are available for meningococcal disease, they are not mandatory in Bulgaria. Therefore, this statement is incorrect.
A: This statement is correct as Waterhouse-Friderichsen syndrome can occur during meningococcemia due to rapid progression of the infection leading to adrenal gland failure.
B: This statement is incorrect as Neisseria meningitidis is most common in infants, children, and adolescents, with a second peak in young adults.
D: This statement is correct as Neisseria meningitidis is transmitted through respiratory secretions, such as coughing or kissing, especially in close contacts like household members or roommates.
Which are the most suitable materials for isolation of polio viruses
- A. feces, duodenal and bile content
- B. blood, sputum and urine
- C. only feces
- D. feces, nasopharyngeal swabs and cerebrospinal fluid
Correct Answer: D
Rationale: The correct answer is D because polio viruses are primarily found in the gastrointestinal tract and respiratory secretions. Feces, nasopharyngeal swabs, and cerebrospinal fluid are the most suitable materials for isolating polio viruses due to their presence in these body fluids. Feces contain the virus shed from the intestines, nasopharyngeal swabs collect respiratory secretions where the virus may be present, and cerebrospinal fluid is important for detecting the virus in cases of neurological complications. Choices A and B include irrelevant body fluids that are not typically associated with polio virus transmission. Option C is too limited as the virus can also be present in respiratory secretions and cerebrospinal fluid, not just feces.
A Gram-negative, comma-shaped bacterium was isolated from a patient with cholera. What is the most likely causative agent?
- A. Vibrio cholerae
- B. Shigella dysenteriae
- C. Salmonella typhi
- D. Campylobacter jejuni
Correct Answer: A
Rationale: The correct answer is A: Vibrio cholerae. This is because Vibrio cholerae is a Gram-negative, comma-shaped bacterium known to cause cholera. The characteristic shape and the association with cholera make it the most likely causative agent in this case.
Explanation for incorrect choices:
B: Shigella dysenteriae - Shigella dysenteriae is a Gram-negative bacterium that causes bacillary dysentery, not cholera.
C: Salmonella typhi - Salmonella typhi is a Gram-negative bacterium that causes typhoid fever, not cholera.
D: Campylobacter jejuni - Campylobacter jejuni is a Gram-negative bacterium that commonly causes foodborne gastroenteritis, not cholera.