Block 9 Pace 1 Part 2
.JPG "Block 9 Pace 1 Part 2 - Quiz")
Sept 2011
Questions and Answers
- 1.
The figure below depicts the log dose-response curves of five different drugs (A, B, C, D, E) tested in an in vitro system. Which of the following pairs of drugs can fully activate the same receptors?
- A.
Drug A and B
- B.
Drug A and C
- C.
Drug B and C
- D.
Drug D and E
- E.
Drug A and D
Correct Answer
B. Drug A and CExplanation
The log dose-response curves of Drug A and Drug C overlap completely, indicating that they have the same potency and efficacy in activating the receptors. This suggests that both drugs can fully activate the same receptors.Rate this question:
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- 2.
A 65 year old post-menopausal woman complains of vaginal bleeding. An endometrial dilatation and curettage is performed and reveals an increase in normal appearing endometrial tissue. What is the most likely diagnosis?
- A.
Pathologic endometrial hyperplasia
- B.
Pathologic endometrial metaplasia
- C.
Physiologic endometrial hypertrophy
- D.
Physiologic endometrial hyperplasia
- E.
Pathologic endometrial hypertrophy
Correct Answer
A. Pathologic endometrial hyperplasiaExplanation
The most likely diagnosis in this case is pathologic endometrial hyperplasia. This is suggested by the increase in normal appearing endometrial tissue observed during the endometrial dilatation and curettage procedure. Pathologic endometrial hyperplasia refers to the abnormal proliferation of endometrial glands and stroma, which can be caused by hormonal imbalances or other factors. It is commonly associated with post-menopausal bleeding and can be a precursor to endometrial cancer.Rate this question:
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- 3.
A 50 year old Caucasian man complains of chest pain which radiates to the left arm. His past medical history is significant for poorly controlled hypertension. Physical exam reveals an obese diaphoretic man in acute distress. His vital signs reveal an increase in the respiratory and pulse rates as well as an elevated blood pressure. A complete blood count with differential and chemistry panel was done upon arrival to the ER and showed a neutrophilic leukocytosis. His EKG was abnormal with S-T segment elevations. Despite thrombolytic therapy the patient dies. A consent for autopsy was obtained from his wife. What would you expect to find upon microscopic examination of the heart?
- A.
Neutrophils invading the hyperplastic myocardial cells
- B.
Neutrophils invading the hypertrophied myocardial cells
- C.
An acute inflammatory infiltrate invading apoptotic myocardial cells
- D.
A chronic inflammatory infiltrate invading necrotic myocardial cells
- E.
Neutrophils invading necrotic myocardial cells
Correct Answer
E. Neutrophils invading necrotic myocardial cellsExplanation
Upon microscopic examination of the heart, one would expect to find neutrophils invading necrotic myocardial cells. This is because the patient's symptoms, such as chest pain radiating to the left arm, elevated blood pressure, and abnormal EKG with S-T segment elevations, are consistent with a myocardial infarction (heart attack). During a myocardial infarction, there is necrosis of myocardial cells due to inadequate blood supply, and the body's immune response leads to infiltration of neutrophils into the necrotic tissue.Rate this question:
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- 4.
Micro Dr Drum A clinical specimen is examined by light microscopy using a variety of staining techniques. The first image shows the results of a Gram stain (cells marked by arrows) and the second those obtained by Ziehl-Neelsen staining (make sure you look at the colour versions!). To what genus does the organism most likely belong?
- A.
Ureaplasma
- B.
Chlamydophila
- C.
Mycobacterium
- D.
Streptococcus
- E.
Leptospira
Correct Answer
C. MycobacteriumExplanation
The correct answer is Mycobacterium. This is because the second image shows acid-fast staining, which is characteristic of Mycobacterium species. Ureaplasma and Chlamydophila are both bacteria that do not stain with acid-fast techniques. Streptococcus is a Gram-positive bacterium that would not show acid-fast staining. Leptospira is a spirochete bacterium that also does not stain with acid-fast techniques. Therefore, Mycobacterium is the most likely genus based on the staining results.Rate this question:
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- 5.
When transcription terminates after a stem-loop structure is formed in the messenger RNA the process is called:
- A.
Sigma factor-dependent termination
- B.
Rho-independent termination
- C.
Elongation factor closing
- D.
DNAse-dependent termination
- E.
Rho-dependent termination
Correct Answer
B. Rho-independent terminationExplanation
Rho-independent termination occurs when transcription terminates after a stem-loop structure is formed in the messenger RNA. In this process, the stem-loop structure causes the RNA polymerase to pause, allowing the RNA transcript to dissociate from the DNA template. This termination mechanism does not require the involvement of the Rho protein or any other factors, hence the term "Rho-independent."Rate this question:
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- 6.
What is the name for a set of genes that share a common promoter?
- A.
Operator
- B.
Operon
- C.
Negative regulation
- D.
Positive regulation
Correct Answer
B. OperonExplanation
An operon is a set of genes that are transcribed together under the control of a single promoter. The genes in an operon are usually involved in a related biological process or pathway. The promoter region of the operon is responsible for initiating the transcription of all the genes in the operon. This allows for coordinated regulation of gene expression, as the genes are transcribed as a single unit.Rate this question:
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- 7.
bacterial culture expressing virulence factor VF (VF+) is treated with DNAse after reaching decline phase causing DNA fragmentation. A cell-free extract of culture VF+ is added to a culture lacking VF (VF-) followed by incubation for 24 hours. Which of the following processes would be necessary to achieve growth of VF+ microbes in this system?
- A.
Induction
- B.
Lysogeny
- C.
Transduction
- D.
Transformation
- E.
Conjugation
Correct Answer
D. TransformationExplanation
The correct answer is Transformation. In this scenario, the bacterial culture expressing the virulence factor VF (VF+) is treated with DNAse, causing DNA fragmentation. The cell-free extract of the VF+ culture is then added to a culture lacking VF (VF-). Transformation is the process by which foreign DNA is taken up by a bacterial cell and incorporated into its genome. In this case, the VF- culture would need to undergo transformation in order to acquire the VF gene and express the virulence factor, allowing for the growth of VF+ microbes in the system.Rate this question:
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- 8.
Micro Dr Ad What cytokines are produced by Th1 cells for the promotion of cell-mediated immune responses?
- A.
IL-1 and IL-6
- B.
IL-4 and IL-5
- C.
IL-10 and IL-12
- D.
IL-2 and IFN-γ
- E.
TNF-α and FasL
Correct Answer
D. IL-2 and IFN-γExplanation
Th1 cells are a subset of T helper cells that play a role in cell-mediated immune responses. They produce cytokines to promote the activation and proliferation of cytotoxic T cells and macrophages. IL-2 and IFN-γ are the cytokines produced by Th1 cells. IL-2 is important for the proliferation and differentiation of T cells, while IFN-γ enhances the activity of macrophages and promotes the production of other pro-inflammatory cytokines. These cytokines are crucial for the development of an effective cell-mediated immune response against intracellular pathogens.Rate this question:
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- 9.
Cytokine receptors are essential for the mediation of a number of important immunological functions. Which of the following property is characteristic of CR1?
- A.
Functions by binding and inactivating complement proteins
- B.
Present on erythrocytes and binds immune complexes for removal
- C.
Found on macrophages and signals host cells to make opsonin
- D.
Activates complement on the surface of pathogens
- E.
Inhibits complement attachment to the surface of host cells
Correct Answer
B. Present on erythrocytes and binds immune complexes for removalExplanation
CR1 is a cytokine receptor that is present on erythrocytes and binds immune complexes for removal. This means that CR1 plays a role in the clearance of immune complexes from the bloodstream by binding to them on the surface of erythrocytes. This helps to prevent the accumulation of immune complexes and promotes their elimination from the body.Rate this question:
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- 10.
Pharmacology: Dr B A 35-year-old man was admitted to the hospital because of anorexia, weight loss and fever for the past three weeks. Lab exams confirmed the diagnosis of endocarditis due to Enterococcus faecalis. An appropriate therapy was started which included an IV injection of amikacin. The drug has a Vd of about 20 L and a half-life of about 2 hours. A blood test showed that the plasma concentration of the drug was 2.5 mg/L, 4 hours after administration. Which of the following was most likely the dose given to the patient (in mg)?
- A.
200
- B.
85
- C.
50
- D.
125
- E.
400
Correct Answer
A. 200Explanation
The plasma concentration of the drug 4 hours after administration is 2.5 mg/L. Since the half-life of the drug is 2 hours, it means that after 4 hours, the drug concentration would have decreased by half. Therefore, the initial concentration after administration would have been 5 mg/L. The volume of distribution (Vd) is 20 L, which means that the drug is distributed throughout a large volume in the body. To calculate the dose given to the patient, we can use the formula: dose = concentration x Vd. Plugging in the values, dose = 5 mg/L x 20 L = 100 mg. Therefore, the most likely dose given to the patient is 200 mg.Rate this question:
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- 11.
Immune Dr Sl As a researcher, you’re trying to develop a therapeutic antibody. You’ve immunized rabbits with an antigen X and isolated the rabbit anti-X antibodies (rAnti-X). You’re concerned that introduction of those rabbit antibodies into humans would cause the formation of human antibodies against the rabbit Fc region of rAnti-X antibodies. You want to treat the rAnti-X antibodies with an enzyme that will cleave the Fc portion away but leave the 2 antigen-binding domains remain linked. Cleavage of rAnti-X with which enzyme or chemical would produce this product?
- A.
Pepsin
- B.
Papain
- C.
Pepsin + Papain
- D.
Betamercaptoethanol (cleaves disulfide bonds)
- E.
None of the above
Correct Answer
A. PepsinExplanation
Pepsin is the correct answer because it is an enzyme that specifically cleaves the Fc portion of antibodies, leaving the antigen-binding domains intact. This would effectively remove the part of the antibody that could potentially cause an immune response in humans, while still retaining the ability of the antibody to bind to its target antigen. Papain is also an enzyme that can cleave antibodies, but it would cleave both the Fc and the antigen-binding domains, resulting in the loss of the antibody's ability to bind to its target.Rate this question:
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- 12.
A specimen collected from the sinuses of a 65-year old man is positive for Actinomyces sp. Which image below best represents the appearance of a Gram-stain of this organism?
- A.
A
- B.
B
- C.
C
- D.
D
Correct Answer
D. D -
- 13.
A 4-month old child is referred to a specialist because she has had recurrent severe infections, chronic diarrhea and failure to thrive. Her lymphocyte counts are low, and a detailed analysis reveals that she has normal numbers of CD8 T cellsand a total absence of CD4 T cells. Failure to express which of the following would potentially lead to this phenotype?
- A.
RAG-1 and RAG-2
- B.
MHC Class I
- C.
MHC Class II
- D.
CD28
- E.
IL-2
Correct Answer
C. MHC Class IIExplanation
The correct answer is MHC Class II. MHC Class II molecules are responsible for presenting antigens to CD4 T cells, which play a crucial role in activating the immune response against infections. Without MHC Class II expression, CD4 T cells cannot recognize and respond to antigens properly, leading to recurrent infections, chronic diarrhea, and failure to thrive. The absence of CD4 T cells also explains the low lymphocyte counts observed in the patient.Rate this question:
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- 14.
Clostridium difficile is an important cause of nosocomial diarrhea and disease in C. difficile colitis is mediated by toxins produced by the organism. Which type of laboratory test would be the most rapid and efficient way of confirming infection with this organism?
- A.
Cultivation of the microbe on semi-solid media
- B.
Detection of the patient’s immune response against the organism
- C.
Cultivation of the microbe in cell lines
- D.
Detection of the toxin produced by the organism
- E.
Gram stain of specimen
Correct Answer
D. Detection of the toxin produced by the organismExplanation
Detection of the toxin produced by the organism would be the most rapid and efficient way of confirming infection with Clostridium difficile. This is because C. difficile colitis is mediated by toxins produced by the organism, so detecting the presence of these toxins would directly indicate an infection. This method does not require the time-consuming process of cultivating the microbe in a laboratory setting, making it a faster and more efficient option for diagnosis. Additionally, this method focuses on the specific cause of the disease rather than relying on the patient's immune response or general cultivation techniques.Rate this question:
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- 15.
A 52-year-old woman, suffering from generalized anxiety disorder, started a therapy with paroxetine, 10 mg tablet daily. Paroxetine has a half life of about 18 hours and a Vd of 1200 L. Which of the following will be the time (in hours) to reach one half of steady-state plasma drug concentration in this patient?
- A.
72
- B.
18
- C.
36
- D.
144
- E.
9
Correct Answer
B. 18Explanation
The time to reach one half of steady-state plasma drug concentration is equal to the half-life of the drug. In this case, the half-life of paroxetine is 18 hours. Therefore, it will take 18 hours for the drug concentration to reach one half of steady-state levels in this patient.Rate this question:
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- 16.
Five new antihypertensive drugs have been tested on hypertensive patients. Each drug has a unique overdose toxicity. The results are reported below. Which of the drugs has the highest risk of overdose toxicity?
- A.
A
- B.
B
- C.
C
- D.
D
- E.
E
Correct Answer
A. AExplanation
Based on the information provided, drug A has the highest risk of overdose toxicity among the five new antihypertensive drugs.Rate this question:
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- 17.
A 23 year old Asian woman complains of fever, chills, malaise, loss of appetite, and sleeping more than usual. Her vital signs are significant for an increase in pulse, respiratory rate, blood pressure and temperature. You are asked to draw a blood sample and order a complete and differential blood count. The patient is afraid of needles and reluctant to have you draw blood. She does not want to be stuck with a needle, unless it is absolutely necessary. Which of the following explanations is correct in convincing this patient of the importance of this blood test?
- A.
Identifying increases in white blood cell counts is critical to diagnosing infections and proper treatment
- B.
Identifying the specific type of virus, bacteria, or parasite is vital to diagnosis and treatment
- C.
Identifying any abnormalities in the type and number of white blood cells is critical to diagnosing and treating the cause of her illness
- D.
Identifying increases and decrease in blood cells must be done on every patient with her symptoms
- E.
Drawing blood and ordering test are important to making any diagnosis
Correct Answer
C. Identifying any abnormalities in the type and number of white blood cells is critical to diagnosing and treating the cause of her illnessExplanation
The patient is experiencing symptoms such as fever, chills, malaise, loss of appetite, and increased sleeping, which are indicative of an underlying illness. Drawing a blood sample and ordering a complete and differential blood count can help identify any abnormalities in the type and number of white blood cells. This is important because changes in white blood cell counts can provide valuable information about the presence and nature of an infection or other underlying condition. By identifying these abnormalities, the healthcare provider can make an accurate diagnosis and provide appropriate treatment for the cause of the patient's illness.Rate this question:
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- 18.
A 65 year old breast cancer survivor complains of feeling multiple small subcutaneous nodules at her healed surgical incision site. A biopsy of one of the nodules reveals a collar of lymphocytes surrounding an area with multinucleated giant cells and central necrosis. The patient is anxious and believes her breast cancer has reoccurred and spread. Which of the following explanations would you offer?
- A.
This is most likely an abscess that resulted from infection at the incision site
- B.
This is most likely a foreign body granuloma that has resulted from a chronic inflammatory response to sutures
- C.
This is most likely a foreign body granuloma that has resulted from suppurative inflammation
- D.
This is most likely metastatic breast cancer that has outgrown its blood supply and become necrotic
- E.
This is most likely a focus of acute inflammation that has resulted from bacterial infection surrounding the suture site
Correct Answer
B. This is most likely a foreign body granuloma that has resulted from a chronic inflammatory response to suturesExplanation
when macrophages fuse they become Multi Nucleated Giant Cells.Rate this question:
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- 19.
Behavioral Science: Dr. Sa A group of physicians wishes to develop a test to assess the mood of their patients. Given that the construct of "mood" is theorized to be highly variable, even within a single individual, which of the following test characteristics can be largely ignored by the test developers?
- A.
Construct-related validity
- B.
Content-related validity
- C.
Criterion-related validity
- D.
Internal consistency
- E.
Test-retest reliability
Correct Answer
E. Test-retest reliabilityExplanation
Test-retest reliability can be largely ignored by the test developers when developing a test to assess mood. This is because mood is theorized to be highly variable, even within a single individual, meaning that a person's mood can change over time. Therefore, the consistency of test results over time (test-retest reliability) may not be as relevant or important in assessing mood compared to other characteristics such as construct-related validity, content-related validity, criterion-related validity, and internal consistency.Rate this question:
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- 20.
behav Dr. Ab Dr. Suave, upon entering the examination room, observed an Asian female patient who appeared to be approximately 50 years of age. As Dr. Suave commenced to interview the patient, he quickly became aware of the fact that the patient was avoiding eye contact. Dr. Suave had the urge to request that the patient look at him when she spoke. Dr. Suave refrained. He remembered a communication skill which he had learned 27 years ago in Dr. Abney’s lecture at Ross. Which of the communication skill sets below best describes the skill set which the doctor remembered?
- A.
Ethics and multicultural competencies
- B.
Attending behaviors
- C.
Observation skills
- D.
Paraphrasing
- E.
Authenticity or congruence
Correct Answer
A. Ethics and multicultural competenciesExplanation
The doctor remembered the skill set of ethics and multicultural competencies because he observed that the patient was avoiding eye contact, which could be due to cultural differences or personal discomfort. Instead of requesting the patient to look at him, the doctor refrained and respected the patient's behavior, showing an understanding of different cultural norms and the importance of respecting individual differences.Rate this question:
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- 21.
Behavior Dr. Sh A 24-year-old female has the persistent belief that she has a heart condition that would likely lead to a heart attack. She complains of recurring palpitations for the past six months which started after a relationship break up. She has seen several doctors and has had a complete cardiac work-up including cardiac enzymes, EKG, and echo cardiogram, which have all been negative. In addition she has had all baseline studies and other relevant specialized studies including thyroid function tests, which were all normal. She was told by one physician that she was a hypochondriac. She reacted angrily to that information and is now seeking your advice and treatment to prove that she does have something wrong with her heart. You take a detailed and careful history and complete your own physical examination of her. You find nothing physically wrong with her. Which of the following represents the most appropriate approach to managing this patient?
- A.
Tell her that nothing is wrong physically
- B.
Refer her to a psychiatrist
- C.
Redo all of the previous tests to finally confirm that she is normal
- D.
Be prepared to provide long term supportive therapy.
- E.
Insist that she sees a counselor.
Correct Answer
D. Be prepared to provide long term supportive therapy.Explanation
Based on the information provided, the most appropriate approach to managing this patient is to be prepared to provide long term supportive therapy. This patient's persistent belief that she has a heart condition despite negative test results suggests that she may be experiencing somatic symptom disorder or illness anxiety disorder. Offering long term supportive therapy can help address her underlying psychological concerns and provide her with the necessary support and coping strategies to manage her symptoms effectively. Referring her to a psychiatrist or insisting that she sees a counselor may also be beneficial as part of the long term supportive therapy.Rate this question:
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.JPG "Micro Dr Drum
A clinical specimen is examined by light microscopy using a variety of staining techniques. The first image shows the results of a Gram stain (cells marked by arrows) and the second those obtained by Ziehl-Neelsen staining (make sure you look at the colour versions!).
To what genus does the organism most likely belong?")
.JPG "A specimen collected from the sinuses of a 65-year old man is positive for Actinomyces sp. Which image below best represents the appearance of a Gram-stain of this organism?")
.JPG "Five new antihypertensive drugs have been tested on hypertensive patients. Each drug has a unique overdose toxicity. The results are reported below.
Which of the drugs has the highest risk of overdose toxicity?")
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