Block 27

Question 1

Systemic arterial pressure during inspiration fall

Pulsus paradoxus

Answer 1

• pulsus paradoxus refers to an exagerated drop in the systolic BP during inspiration.
• its detected by inflating BP cuff above systolic BP and gradually deflating it
  -the difference between the systolic BP at which kortokff sounds first become audible during expiration and the pressure at which they are heared throughout all the phases of respiration quantifies pulsus paradoxus.
  asthma and COPD are the most frequent causes of pulsus paradoxus in the absence of significant pericardial disease

Question 2

Physiological changes done to relieve COPD excacerbation

Answer 2

Acute obstructive pulmonary excacerbation is treated with beta agonist, which produces relaxation of bronchial smooth muscles by stimulating the beta 2 adrenergic receptor.
-the receptor is a Gs protein coupled protein coupled receptro that activates adenylyl cyclase and increase intracellular cAMP concentration.

Question 3

Types of incontenece

Answer 3

1. Stress (decreased urethral sphincter tone with urethral hypermotility, present with leakage with couging lifting and sneezing).
2. Urge (detrusor hyperactivity, present as sudden overwhelming urge to urinate)
3. Overflow (impaired detrusor contractility, bladder outlet obstruction, presents with incomplete emptying and persistent involuntary dribbling.

Question 4

Voltage gated calcium channels in neurons

Answer 4

When the action potential reaches the axon terminal, voltage gated calcium channels open and allow the influx of calcium which is essential for the fusion and release of neurotransmitter vesicles into the synaptic cleft.
-GABAPENTIN is anticonvulsant that act by inhibiting presynaptic voltage gated calcium channels.

Question 5

Diphenoxylate

Answer 5

Is an opoid antidiarrheal agent structually related to mepiridine. It binds ti mu receptors in GI tract and slows motility.
-to discourage abuse its given along with atropine which produces adverse symptoms if taken in high doses.

Question 6

Congenital long QT syndrome

Answer 6

• usually due to potassium channels mutation that contribute to outward rectifying potassium current.
• decreased outward K+ flow due to K+ channel mutation leads to prolongation of AP duration and QT interval.
• this may predispose to development of life threatining arrythmias (torsades de pointes)

Question 7

Dimpling in breast cancer is due to

Answer 7

• Malignant invasion of the suspensory ligament.
• invasive breast carcinoma typically presents as an irregularly shaped adherent breast mass.
• overlying skin retraction (dimpling) signal involvement of suspensory ligaments of the breast (cooper ligament), malignant infiltration of these ligaments causes fibrosis and shortening, leading to traction on the skin with distortion in breast contour.

Question 8

If a drug is secreted in the liver what is the main condition of a drug to be

Answer 8

High lipophillic (lipid soluble) allows drug to cross cellular barriers more easily and enter hepatocytes.

Question 9

Chronic bronchitis biopsy results

Answer 9

1. Thickened bronchial walls
2. Neutrophilic infiltrates
3. Mucus gland enlargement
   4, patchy squamous metaplasia of bronchial mucosa.

Question 10

Migratory thrombophelibits

Answer 10

• usually raise the suspicion for cancer
• hypercoagulability is a very common paraneoplastic syndrome seen in adenocarcinoma of pancreas, colon and lung,this is due to the production of thromboplastin like substance capable of causing chronic intravascular coagulation that can disseminate and tend to migrate.
• migratory thrombophlebitis known as trusseau syndrome.

Question 11

Raltegravir

Answer 11

• integrase inhibitor
• inhibts ability of Ds HIV DNA to integrate into host cell chromosome —> thus in the absence of integration, viral genome transcription by host cellular machinery and eventually degraded by nucleases.

Question 12

In femoral neck fracture increase risk for ?

Answer 12

-increase femoral head risk for osteonecrosis if its blood supply interrupted. The blood supply to the femoral head derives mainly from the ascending cervical and retinacular branches of the medial cicumflex artery .

Question 13

Asplenic sepsis

Answer 13

• usually patients have a history of previous trauma that lead to spleen resection
• sepsis with encapsulated organs leads to life threatining infection (s.pneumoniae sepsis …)

Question 14

P53 deficiency

Answer 14

Is one of the few tumor suppressor gene (along with rb) its absence leads to neoplasm formation

Question 15

PrP stands for

If it changes the neuron from a-helical secondary structure to b-pleated sheet isoform

Answer 15

• PrP stands for prion protein
• its normally found in neurons and has an a helical structure. If the conversion of a helix into ß-pleated sheet occurs, the protein becomes resistant to protease —> prion disease if accumulated.

Question 16

Pneumonia stages

Answer 16

1. Congestion
2. Red hepatization
3. Gray hepatization
4. Resolution

Question 17

Nuclear factor kappa B

Answer 17

Also stands for NF-kB

• is part of the family of transcription factors that performs a critical role in the immune response to infection and inflammation.
• in inflammatory cells NF-kB is normally present in latent state inactivated by IkB protein bound to it.
• activation of IkB kinase(in infection) leads to ubiquitination and destruction of IkB with release of NF-kB.
• once free NF-kB —> enter nucleus —> promotes synthesis of inflammatory proteins —?> also stimulates more unbinding of NF-kB

Question 18

Krukenbrg tumor

Biopsy

Answer 18

-gastric tumor that has metastasized to the ovary.
-histologic feature is nests of signet ring cells.
- the appearance is a result of large amounts of mucin displacing the nucleus.
-

Question 19

Mechanism in which hepatitis B leads to hepatocellular carcinoma

Answer 19

• not very much clear, however integration of viral DNA into the cellular genome of the host is considered a trigger of neoplastic changes.
• the viral protein HBX —> increased IGF I and II —> cell proliferation.
• another effect is suppression of p53.

Question 20

Class 1B antiarrythmic indication

Answer 20

• these are the weakest sodium channel blockers compared to other class I antiarrythmics
• they predominantly binds to sodium channels in the inactivated state, and dissociation from the channels occurs so rapidly that they have negligible effect on QRS duration on normal cardiac tissues.
• ischemic myocardium has higher than normal resting membrane potential which delays voltage dependent recovery of sodium channels from the inactivated to resting state. —> that allow IB agents to bind to it.
• thus class IB is used in ischemia induced ventricular arrythmia (especially after MI)

Question 21

Anterior dislocation of humerus can lead to

Answer 21

• its the most commonly dislocated joint in the body due to shallow articulation between the humoral head and the glenoid fossa of the scapula.
• the shoulder may dislocated anteriorly,posteriorly or laterally
• anterior dislocation leads to flattening of the deltoid prominence, protrusion of the acromion and anterior axillary fullness.

Question 22

Homocystenuria -supplementation

Answer 22

• its the most common inborn error of methionine metabolism. Most patients present at age 3-10 with ectopia lenitis (dislocated lens). Half of the patients have intelectual disability and patients may have marfanoid habitus.
• pts are at high risk of thromboembolic occlusion of both large and small vessels, especially those of the brain, heart and kidneys.
• homocysteinuria is most frequently requires pyridoxine as a cofactor, approximately 50% respond to high dose of pyridoxine which improves residual enzymatic activity and reduces plasma homocysteine levels.
• additional treatments include dietery restriction of methionine.

Question 23

Median nerve course

Answer 23

• it travels in the arm between brachialis and biceps brachi.
• it gains access to the forearm in the medial aspect of antecubital fossa and courses between the humeral and ulnar heads of the pronator teres muscle.
• the nerve then travels between the flexor digitorum profondus muscles before entering the wrist within flexor retinaculum.

Question 24

Muscarinic receptor action

Answer 24

M1 =memory and cognitive function
M2= heart , decrease HR and atrial contraction
M3=
1.peripheral vasculature :smooth muscle relaxation, vasodilation and hypotension.
2. Lung: bronchoconstriction
3.bladder: contraction detrusor
4.eyes: miosis, accomodation
5, GI: increase peristalisis and salivary gland secretion
6. Skin: increase sweat production.

Question 25

Drug induced lupus is the result of which metabolic process abnormality

Answer 25

Liver acetylation of isoniazid, hydralazine, procinamide, minocycline and etanercept

Question 26

Immune system againt M.TB

Answer 26

- cell mediated immunre response since its facultative intracellular organism - macrophages present the antigen to CD4 cell—> IFN-y and IL-2 activation of macrophages and CTL, —> walling of of Tb with creation of ceseating granuloma —> eptheloid cells, langhans multinucleated giant cells, fibroblast and collagen.

Question 27

Disseminated gonococcal infection

Answer 27

1. Polyarthralgia 2. Skin lesions 3. Tenosynovitis

Question 28

Microbiology of human and animal bites

Answer 28

1. Cat bites: -MCC -> pasturella multicoida , bartoenlla henselae 2. Dog bites - pasturella multicoida, streptococci and s.aureus 3. Human: - anaerobes, streptococci, eikenella corrodens

Question 29

Q-fever

Answer 29

Caused by coxiella brunetii , mild form pneuomonia, fusobacterium is part of the anaerobic oral flora potentially causing aspiration pneumonia or pharyngitis. (Lemierre disease ).

Question 30

Effects of prolonged corticoids therapy

Answer 30

1. Adipose (lipolysis, altred fat distribution) 2. Adrenal cortex (atrophy) 3. Bone osteoporosis 4. Immune system(suppression and t cell apoptosis) 5liver (increased gluconeogenesis and glygogenolysis 6. Skeletal muscle atrophy 7. Thining, striae and imapired wound healing of the skin

Question 31

What is the most common karyotype for molar pregnancy

Answer 31

Complete mole : most commonly 46,XX | Partial: might be both 69,XXX or 69,XXY

Question 32

Chyne stokes respiration

Answer 32

Commonly seen in CHF . Is a cyclic breathing pattern in which is apnea is followed by gradually increasing then decreasing tidal volumes until the next apneic period. - patients with CHF have chronic hyperventilation with hypocapnia which induces apnea during sleep when he partial pressure of carbon dioxide, this stimulate ventilatory response that overshoots causing the PaCO2 to again fall below the apneic threshold.

Question 33

Which action in RNA transcription occurs only at the cytoplasm

Answer 33

- eukaryotic mRNA before leaving the nucleus undergoes posstranscriptional modification which include 5’ capping, poly A tail and intron splicing. - once its finalized, it leaves the nucleus bound to specific packaging proteins. Upon entering the cytoplasm, these mRNA complexes often associates with ribosomes to undergo translation. - however certain mRNa sequences instead associate with protein that are found in the P bodies. - P bodies only present in the cytoplasm of the cell

Question 34

P bodies function

Answer 34

Distinct foci found within eukaryotic cells that are involved in mRNA regulation and turnover. -they play a fundemental role in translation repression and mRNA decay, and contain numerous proteins including RNA exonucleases, mRNA decapping enzymes and constitutes invloved in mRNA quality control and microRNA induced mRNA silencing.

Question 35

Fragile X syndrome is a result of which genetic defect

Answer 35

- gene methylation - its caused by mutation of FMR1 gene on long arm on the x chromosme. - mutation is charactrized by >200 CGG repeates which leads to hypermethylation of FMR1. - DNA methylation inactivates FMR1 preventing transcription and production of fragile x mental retardation protein.

Question 36

Creatine kinase increased following reperfusion is a result of

Answer 36

-cell membrane damage —> leakage of CK

Question 37

Risk factor for pancreatic cancer

Answer 37

1. Age : old age 2. Smoking : msot important envirnomental risk factor for pancreatic cancer (doubles the risk) 3. D.M 4. Chronic pancreatitis (risk is highest after 20 years) 5. Genetic predisposition

Question 38

Meningococcal meningitis - factor that is related to high morbidity and mortality

Answer 38

- gram negative bean shaped diplococci. - the outer membrane lipo “ oligo” saccharide (LOS) of N.meningitidis is analogue to LPS but lacks the repeating O antigen of enteric LPS. - it sometimes acts as endotoxin and is associated with many toxic effects of meningococcal disease. - LOS plasma levels correlate with disease manifestation and outcomes.

Question 39

Cilostazol

Answer 39

Reduces platelt activation by inhibiting platelet phosphodiesterase, the enzyme responsible for breakdown of cAMP. It also a direct vasodilator mainly used in PAD. - the net effect is decreased in claudication symptoms and increase in pain free walking distances in patients with PAD.

Question 40

Nitrates relief of angina symptoms mechanism of action

Answer 40

1. Vasodilation of the peripheral veins and arteries predominantly venodilation 2. Decreased left ventricular wall stress due to reduced preload 3. Modest reduction of afterload due to systemic vasodilation 4. Mild coronary artery dilation and reduction of vasospasm - all of these result in decrease myocardial oxygen demands—> improved exercise tolerance and relief of angina symptoms.

Question 41

renal osteodystrophy

Answer 41

- in CKD, failure of glomelular and tubular function results in hyperphosphatemia and hypocalcemia - increase PTH leading to secondary hyperparathyrodism - PTH mobilizes calcium from bones by activating osteoclast activity. - high turnover osteodystrophy increase bone resorption more than bone formation causing osteopenia and pathalogic bone changes similar to those seen in primary hyperparathyrodism (osteitis fibrosa cystica) - PTS can also develop PTH resistance resulting in low turnover adynamic bone disease and osteomalacia.

Question 42

Cp450 inducers and inhibitors

Answer 42

- phenytoin , phenobarbital, carbamazepine, grisefluvin, rifampin , st john wort, nevirapine all are inducers - ketoconazole, isoniazid, cimitidne, amidoarone, ritonavir, sulfonamides, quinidine, macrolides.

Question 43

Amphotericin B side effects

Answer 43

1. Acute infusion related reaction such as fever, chills ,rigors, and hypotension 2. Dose dependent nephrotoxicity can result due to decreases GFR (creatinine should be monitored ) 3. Significant electrolytes abnormalities ( hypomagnesemia and hypokalemia) 4. Anemia due to suppression of renal erythropoietin synthesis 5. Thrombophlebitis can be seen at the site of injection.

Question 44

Glucose transport across cells

Answer 44

- glucose cant passively diffuse across the cell membrane in any significant amount and requires a carrier proteins to aid its crossing. - transport across the cell membrane by carrier protein is termed carrier mediated transport. - transport is facilitated by transmembrane proteins without expenditure of energy is called facilitated diffusion.

Question 45

Hepatic steatosis

Answer 45

-non specific condition characterized by TAG accumulation within the hepatocellular cytoplasm. -pathogenesis apears to be related to decreases in fatty acid oxidation secondary to excess NADH production by the 2 major alcohol metabolism enzymes, alcohol dehydrogease and aldehyde dehydrogenase. -

Question 46

Reticulocytes - blue color due to

Answer 46

Its in immature RBC that is slightly larger and bluer than mature RBC. It lacks cell nucleus but retains basophilic reticular network of residual ribosomal RNA. The ribosomal RNA appears blue microscopically after the application of wright giemsa stain

Question 47

Mechanism by which hepatitis B assists hepatitis D

Answer 47

-HDAg is considred replication defective as it must becaoted by external coat hepatitis B surface antigen of HBV to penetrate the hepatocyte.

Question 48

Leprosy

Answer 48

Is a chronic , slowly progressive communicable disease caused by mycobacterium leprae that typically involves the skin and peripheral nerves. - clinical manifestation are widely variable depending on the strength of the Th1 cell mediated immune response to the organism. - disease is classified along a spectrum between tuberculoid to lepromatous severe forms .

Question 49

Leprematous leprosy vs tuberculoid

Answer 49

- Tubercouloid leprosy develops strong Th1 mediated response (il-2, and IFN-Y) in affected tissue therby limiting disase extent, this leads to damage to the skin and tissues —> hypopegmented well demarcated plaques with decreased sensation. - lepromatous leprosy is more disseminated charactrized by innate inability to recognize and moint a cellular immune response against M. Leprae antigens . - lepromin skin test is only positive on tuberculoid leprosy.

Question 50

Evaluation of hypoglycemia

Answer 50

1. exogenous insulin :- high insulin,low c-peptide and hypoglycemia drug assay is negative 2. Oral hypoglycemic agents:- normal or increased insulin, normal or elevated C-peptide and positive hypoglycemia drug assay 3. Insulinoma: same as oral hypoglycemic agents but with negative hypoglycemia drug assay.

Question 51

How to prevent stone formation

Answer 51

Drinking plenty of water

Question 52

BRCA gene nvolved in

Answer 52

1. DNA repair. 2. Cellular differentiation 3. Checkpoint control of cell cyclle 4. Transcription factor regulation.