There is a suspicion of active tuberculosis development in patient. The doctor has appointed Mantoux test to make a diagnosis. What immunobiological agent has to be administered?

Correct Answer: A

Rationale: The correct answer is A: Tuberculine. The Mantoux test involves injecting tuberculin, a protein derivative of Mycobacterium tuberculosis, under the skin. This test helps determine if a person has been exposed to the bacteria that cause TB. Administering tuberculin is crucial for the Mantoux test as it triggers a delayed-type hypersensitivity reaction in individuals previously exposed to TB. Choice B (BCG vaccine) is incorrect because BCG does not interfere with the Mantoux test results. Choice C (DPT vaccine) is incorrect as it is used for immunization against diphtheria, pertussis, and tetanus, not for diagnosing TB. Choice D (Tularin test) is incorrect as it is not a recognized immunobiological agent for TB diagnosis.

Correct Answer: D

Rationale: The correct answer is D: scanning electron microscope. A scanning electron microscope provides a three-dimensional image of a specimen by scanning a focused electron beam across the surface of the specimen, detecting the electrons that are emitted from the surface, and creating a detailed image. This is achieved through the detection of secondary electrons, backscattered electrons, and X-rays emitted from the specimen surface. A dark-field microscope (choice A) utilizes oblique lighting to enhance contrast and is not specifically designed to provide a 3D image. A transmission electron microscope (choice B) uses a beam of electrons transmitted through a specimen to create a 2D image at high magnification. A bright-field microscope (choice C) is a basic microscope that illuminates a specimen with uniform light and does not provide a 3D image like a scanning electron microscope does.

Correct Answer: C

Rationale: The correct answer is C: nucleotides. Nucleotides are the structural units of nucleic acids, consisting of a nitrogenous base, a sugar molecule, and a phosphate group. The nitrogenous base can be adenine, thymine, cytosine, guanine, or uracil. Histones (B) are proteins that DNA wraps around in chromosomes, not structural units of nucleic acids. Nucleosides (A) are composed of a nitrogenous base and a sugar molecule but lack the phosphate group present in nucleotides. N-bases (D) is not a recognized term in biology and does not accurately describe the structural units of nucleic acids.

Correct Answer: B

Rationale: The correct answer is B: Zoonosis. Tularemia is primarily a zoonotic disease, meaning it is transmitted from animals to humans. The bacterium that causes tularemia, Francisella tularensis, commonly infects animals like rabbits, rodents, and ticks, which serve as reservoir hosts. Humans can get infected through direct contact with infected animals, insect bites, or contaminated water or soil. This zoonotic nature of tularemia distinguishes it from anthroponosis (A), which is transmitted only between humans, and sapronosis (C), which is transmitted through non-living environmental sources. Choice D is incorrect because there is a correct answer, which is zoonosis.

Correct Answer: A

Rationale: The correct answer is A: OSHA. The Occupational Safety and Health Administration (OSHA) is responsible for setting and enforcing safety standards in the workplace, including bloodborne pathogen training requirements. OSHA's Bloodborne Pathogens Standard mandates training for certain at-risk professions to prevent exposure to bloodborne diseases. The CDC (Choice B) focuses on disease prevention and control, not regulatory enforcement. NIA (Choice C) is the National Institute on Aging and not relevant to bloodborne training. WHO (Choice D) is the World Health Organization, which sets global health standards but does not regulate workplace safety in the same capacity as OSHA.

Correct Answer: A

Rationale: The correct answer is A: Yersinia pestis. Y. pestis is a Gram-negative rod that exhibits a 'safety pin' appearance on staining due to bipolar staining. This bacterium is the causative agent of plague, which can present as painful ulcers known as buboes. Y. pestis is transmitted by fleas and can cause outbreaks in humans. Summary: - B: Francisella tularensis causes tularemia, not typically associated with painful ulcers. - C: Brucella abortus causes brucellosis, which does not typically present with painful ulcers. - D: Clostridium botulinum causes botulism, characterized by muscle weakness and paralysis, not painful ulcers.

Correct Answer: A

Rationale: The correct answer is A: Toxoplasma. Toxoplasma gondii is a protozoan parasite that can infect the brain and cause vision loss. The description of half-moon-shaped organisms with a pointed end matches the appearance of Toxoplasma under the microscope. Toxoplasma is known to cause a condition called toxoplasmosis, which can lead to neurological symptoms such as vision loss. Leishmania, Lamblia, Amoeba, and Trichomonad are not known to cause brain infections or vision loss, making them incorrect choices.

Correct Answer: C

Rationale: The correct answer is C: Granuloma formation. In response to tuberculosis antigen (tuberculin), the immune system forms a granuloma at the injection site as a defense mechanism. Granulomas are organized collections of immune cells that wall off the antigen and prevent its spread. This process involves macrophages, T cells, and fibroblasts. Choice A (Cells cytotoxity) is incorrect because tuberculin test does not involve direct cell cytotoxicity. Choice B (Reagin type cytotoxity) is incorrect as reagin type hypersensitivity is associated with allergic reactions, not granuloma formation. Choice D (Immunocomplex cytotoxity) is also incorrect as immunocomplex cytotoxicity refers to tissue damage caused by immune complexes, not granuloma formation.

Correct Answer: D

Rationale: The correct answer is D because during the incubation period of Salmonella Typhi infection, the bacteria multiply in the macrophages of the Peyer's patches and solitary follicles. This is supported by the fact that S. Typhi is an intracellular pathogen that targets the lymphoid tissues of the intestines. Macrophages in these areas serve as the primary host cells for the bacteria, allowing for their replication and evasion of the host immune response. Choices A, B, and C are incorrect because S. Typhi does not primarily multiply in the small intestine enterocytes, the lumen of the small intestine, or hepatocytes during the initial stages of infection.