Model Test Keys-5-5-2013
Model Test Keys-5-5-2013
1.B 2.B 3.C 4.B 5.D 6.D 7.B 8.C 9.A 10.C 11.B 12.A
13.B 14.A 15.B 16.D 17.D 18.C 19.D 20.A 21.A 22.C 23.C 24.D
25.B 26.D 27.D 28.C 29.C 30.A 31.A 32.D 33.A 34.C 35.D 36.B
37.D 38.A 39.A 40.A 41.B 42.D 43.D 44.D 45.A 46.D 47.A 48.A
49.B 50.D 51.B 52.B 53.A 54.A 55.B 56.B 57.A 58.D 59.B 60.A
61.D 62.A 63.D 64.A 65.C 66.B 67.C 68.A 69.B 70.D 71.D 72.B
73.A 74.A 75.C
76.Ans: D
Significance of drug resistance by transformation in nature is not known.
Acquisition of resistance by transduction is common in staphylococci.
With lysogenic conversion the bacteria usually produce toxins or express certain antigens. No role in drug resistance.
Transfer of drug resistance by “Resistance transfer factor” - also known as infectious drug resistance which is plasmid mediated. This plasmid has 2 components – RTF (resistance transfer factor) and ‘r’ determinant (which carries the information for drug resistance to as many as 8 drugs).
77.Ans: A
Pseudomonas is an obligate aerobe.
Escherichia is a facultative anaerobe.
Bacteroides and clostridium are obligate anaerobes.
78.Ans: A
2types of pneumococcal vaccines available.
a.Pneumococcal capsular polysaccharide vaccine – contains capsular polysaccharide from 23 most prevalent serotypes of S. pneumonia. Recommended for all persons >2 years of age who are at substantially increased risk of developing pneumococcal infection.
b.Protein-Conjugate Pneumococcal Vaccine – capsular polysaccharides conjugated to diphtheria CRM197 protein. This seven valent vaccine is recommended for children below 24 months. Prevents invasive pneumococcal infection. Proved to have “herd effect”.
79.Ans: C
Mycoplasmas are resistant to thallium acetate in a concentration of 1:10000, hence it is used as a selective agent along with penicillin for mycoplasma.
80.Ans: B
Enteroinvasive E. coli (EIEC), such as E. coli O124 and others, cause dysentery that is clinically indistinguishable from Shigella dysentery. Like Shigellae, EIEC invade and destroy colonic mucosa. The invasive property is plasmid-dependent and can be tested in a tissue culture assay on Henrietta Lacks (HeLa) or human epithelial 2 (HEP-2) cell lines. Unlike most E. coli, EIEC do not ferment lactose. (The most common serogroup Among EIEC is O124.
81.Ans: A
The patient’s symptoms and clinical findings indicate a rotavirus infection. Rotaviruses account for approximately 50% of gastroenteritis in children that require hospitalization due primarily to dehydration.
Rotaviruses are in the family Reoviridae, which have a double protein capsid and a double-stranded (ds)RNA genome.
The outer capsid protects the virus as it passes through the stomach. Once in the intestine, proteases cleave the outer capsid, releasing the intermediate/infective subviral particle (ISVP), which attaches and penetrates the host cell.
The dsRNA is very sensitive to degradation if exposed to the environment.
The segmented genome allows for genetic reassortment.
Rotaviruses do not have a lipid envelope.
82.Ans: D
It is the typical description of hook worm infection, which is transmitted by skin penetration by larvae.
Ascaris, pinworm and whipworm infections acquired by ingestion of eggs.
Taenia and Trichinella spread by ingestion of larvae in muscle.
83.Ans: A
Cl.perfringens produces a variety of toxins. The 4 “major toxins” are α, β, ε and ɩ toxins. α toxin is a phospholipidase (Lecithinase C). It is the most important toxin biologically and is responsible for the profound toxaemia of gas gangrene. Nagler reaction is used for the rapid detection of Cl.perfringens in clinical specimens.
84.Ans: C
CD28/B7 interaction is the second signal for Tcell activation, the first signal being interaction of T cell receptor with antigen presented by the suitable MHC molecule.
85.Ans :D
Needle stick injuries and cuts should be washed with soap and water. Do not put pricked finger reflexly into mouth. No scientific evidence shows that the use of antiseptics for wound care or squeezing the wound will reduce the risk of transmission of HIV.
86.Ans: B
In an area with no history of a disease, one case represents an epidemic.
The terms enzootic and epizootic are both used to describe diseases that occur in animals and are present in the animal community at all times. If a disease is enzootic, it occurs in small numbers. If the disease is epizootic, its attack rate is at least one standard deviation above the normal endemic rate of disease occurrence.
In an area with no history of a disease, there is no herd immunity to the disease. Herd immunity in an animal community or a human community develops after a large number of community members become infected or vaccinated and then become immune.
87.Ans: D
Endotoxin, also called lipopolysaccharide or lipo-oligosaccharide is a component of the outer membrane of GNB and is released from the bacterial surface via outer membrane vesicles following natural lysis of the bacterium or by disintegration of the organism in vitro.
88.B 89.B 90.C 91.C 92.C 93.B 94.C 95.C 96.B 97.A 98.D 99.D
100.C 101.C 102.D 103.C 104.C 105.C 106.D 107.C 108.B 109.C 110.B 111.C
1112.C 113.A 114.D 115.C 116.C 117.A 118.D 119.A 120.C 121.B 122.A
123.B 124.C 125.B 126.C 127.C 128.B 129.A 130.C 131.C 132.A 133.C 134.C
135.C 136.D 137.D 138.A 139.A 140.D 141.A 142.D 143.A 144.A 145.D 146.
147.B 148.D 149.B 150.A
151.Answer:B
After the nasal bones, the mandible is the second most commonly fractured facial bone.
152.Answer: D
DISCUSSION: Single-lung transplantation is still offered up to age 65 years. Current low-dose corticosteroid therapy has not been demonstrated to lead to a higher risk of airway complications after lung transplantation. Advancements in operative technique have lessened the risk of surgery, so prior thoracotomy is no longer a contraindication to lung transplantation. However, patients with chronic ventilator-dependent respiratory failure who have no potential for cardiopulmonary rehabilitation currently are not accepted for evaluation for potential lung transplantation.
153.Answer: D
DISCUSSION: The greater saphenous vein has proved to be the most satisfactory and most commonly used arterial substitute. The wall is sufficiently strong to withstand arterial pressures without becoming dilated or aneurysmal, yet is flexible and easily sutured. The diameter is sufficiently great to avoid thrombosis and nourishment is provided by the intraluminal blood flow. The smooth, natural endothelial lining is less thrombogenic than any known synthetic surface. The lining surface heals itself and may sequester white cells to fight infection, unlike Dacron grafts, which provide a haven for infecting organisms in the interstices of their synthetic fibers. Saphenous vein autografts heal even when placed into the infected bed of a previous synthetic graft.
154.Ans C Lt atrial myxoma arises from interatrial septum. Commonest metastatic deposit in heart is from bronchogenic Ca. Commonest tumour of heart in children Rhabdomyosarcoma.
155.A 156.D 157.B 158.C 159.D
160.Answer: B
DISCUSSION: The right atrial approach is preferred for the repair of most perimembranous VSDs. Prompt intracardiac repair is indicated for infants with large defects, large shunts, and pulmonary hypertension who present with intractable left ventricular failure, recurrent pulmonary infections, severe growth failure, or evidence of increasing pulmonary vascular resistance. In the modern era, complete heart block requiring a permanent pacemaker is a very uncommon complication of surgical closure of a ventricular septal defect. Hospital mortality after closure of a VSD currently approaches zero. While in earlier years younger age was an incremental risk factor for hospital death in some surgical experiences, this risk has been neutralized during the past decade.
161.C
162.Answer: D
DISCUSSION: Pituitary prolactinomas are the most common pituitary tumor and cause amenorrhea, galactorrhea, or both in women. Men usually have macroprolactinomas and experience symptoms of a space-occupying lesion of the sella (i.e., headache). A minority of men experience impotence and infertility. Asymptomatic prolactinomas remain stable over time and require observation only. Symptomatic prolactinomas require treatment, usually with bromocriptine. Prolactinomas may enlarge during pregnancy and can produce symptoms requiring treatment with either bromocriptine or surgery. Prolactiomas are seen in as many as 40% of patients with MEN 1.
163.D 164.B
165.Answer: C Because it could be Pheochromocytoma
166.Answer: D
Patients with hypersplenism from portal hypertension usually present with thrombocytopenia as the primary manifestation. The role of splenectomy in such patients is controversial. Although splenectomy may transiently increase the number of platelets in the peripheral circulation, it generally does not improve survival. At the time of surgery, these patients have considerable risk for massive bleeding and subsequent complications related to hepatic dysfunction. These latter complications include ascites, coagulopathy, and wound complications. The severity of the underlying liver disease is the determining factor for these patients. Some believe that splenectomy is contraindicated in patients with portal hypertension. Indeed, the perioperative risks are considerably greater than normal. This should be considered as a last option, and even then with the realization that the operative and preoperative morbidity and mortality are high. In the absence of gastrointestinal bleeding, this particular patient has no indication for either sclerotherapy or portosystemic shunting.
167.Answer: B
DISCUSSION: CA 15-3 is a marker for breast cancer. AFP is a marker for hepatocellular and testicular cancer. CEA is a marker for colon cancer. CYFRA 21-1 is a marker for non–small-cell lung cancer. CA 19-9 is a marker for pancreatic cancer.
168.Answer: c
patients with immune deficiency or immunosuppressed transplant recipients are at greater risk for neoplastic disease. Frequently these are tumors of the lymphoreticular system, and only selected nonlymphoid tissues exhibit increased incidence of neoplasia. Patients with acquired immunodeficiency syndrome and some transplant patients are at an increased risk for Kaposi’s sarcoma.
169.D 170.B 171.A 172.B 173.C 174.D 175.C 176.A 177.B 178.A 179.B 180.A
181.D 182.A 183.A 184.B 185.D 186.A 187.D 188.B 189.B 190.C 191.B 192.A
193.B 194.A 195.B 196.A 197.C 198.D 199.A 200.C
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