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nbme 5 block 2 -q1 to q 50 - drona99
#31
25.AA
Influenza hemagglutinin is a type of hemagglutinin found on the surface of the influenza viruses. It is an antigenic glycoprotein. It is responsible for binding the virus to the cell that is being infected.
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#32
26.EE

1-STEROID HARMONE RECEPTARS STRUCTURE

Steroid harmone receptars are present INTRACELLULARLY *
They are composed of polypeptide contain one ZINC atom which bound to four cystein residue .
They also have gene regulatory proteins that have one harmone binding domain and one DNA binding region [which activates transcription].


Mechanism of gene transcription ---
these inactive steroid receptars are present in the cytoplasm and bound to heat shock protein 90 ie hsp90 and immunophillin hsp56.[these hsp covers DNA binding regions]


* When steroid harmone diffuses across the cell membrane and bind to harmone binding site of receptar hsp90 and hsp56 are relased ---------this now leads to exposure of DNA binding site or region.

----Now this steroid -receptar complex is transported to the nucleus where it binds to DNA and activates transcription of small number of specific gene within 30 seconds -[this is primary response]
----gene product of primary response activates other gene to produce secondary response .

eq of streoid receptars-
1-glucocoticoids
2-estrogen
3-progesteron
4-thyroid harmones ie T3/T4
5-Retinoic acid receptar
6-vitamin D3.

mechanism diagramme
http://www.rise.duke.edu/phr150/Performa...sponse.jpg

posted by drona99

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#33
27.DD
vit B12 is found in animal products.Human body has very large reserve pool of it,but its deficiency is usually caused by Veg.diet ,sprue,enteritis,Diphollobutrium latum,lack of intrinsic factor and absence of terminal ileum due to sergical resection or Crohn's disease
B12 is a cofactor for hemocysteinMethyltransferase and Methylmalonyl.-coA mutase.
.......................................vit B12.......................
Homocystein+N-Methyl THF............>Methionin+THF
Methylmalonyl-coA........................> Succinyl coA
its deficiency causes megaloblastic ,Macrocytic Anemia, NEUROLOGIC SYMPTOMES,,,,LIKE paresthesias,subacute combined degeneration....due to demyelination of neurons
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#34
28.CC
Macrophages are white blood cells produced by the differentiation of monocytes in tissue.
When a leukocyte enters damaged tissue through the endothelium of a blood vessel (a process known as the leukocyte extravasation), it undergoes a series of changes to become a macrophage. Monocytes are attracted to a damaged site by chemical substances through chemotaxis, triggered by a range of stimuli including damaged cells, pathogens and cytokines released by macrophages already at the site.

Functions:
1. Phagocytosis,,,,,,
When a macrophage ingests a pathogen, the pathogen becomes trapped in a phagosome, which then fuses with a lysosome. Within the phagolysosome, enzymes and toxic peroxides digest the pathogen. However, some bacteria, such as Mycobacterium tuberculosis, have become resistant to these methods of digestion. Macrophages can digest more than 100 bacteria before they finally die due to their own digestive compounds.
The removal of necrotic tissue .
2.Role in adaptive immunity,,,,,
After digesting a pathogen, a macrophage will present the antigen of the pathogen to the corresponding helper T cell. The presentation is done by integrating it into the cell membrane and displaying it attached to an MHC class II molecule, indicating to other white blood cells that the macrophage is not a pathogen, despite having antigens on its surface.

Eventually, the antigen presentation results in the production of antibodies that attach to the antigens of pathogens, making them easier for macrophages to adhere to with their cell membrane and phagocytose.

3.Role in Muscle Regeneration.

Tissue Macrophages:
Name of cell Location
Dust cells/Alveolar macrophages pulmonary alveolus of lungs
Histiocytes..... connective tissue
Kupffer cells...... liver
Microglia..... neural tissue
Epithelioid cells..... granulomas
Osteoclasts..... bone
Sinusoidal lining cells.... spleen
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#35
29.DD

A reticulocyte count is usually performed when patients are evaluated for anemia and response to its treatment. It is sometimes called a retic count.
PURPOSE :
1.Diagnosis:
A reticulocyte count provides information about the rate at which the bone marrow is producing red cells. A normal count means that the production is adequate; a decreased count means it is not. This information helps determine whether a lack of red cells in an anemic person is caused by a bone marrow problem, by excessive bleeding, or by red cell destruction.

2.Monitoring:
The test is also used to monitor the response of bone marrow response to treatment for anemia. The reticulocyte count rises within days if the treatment is successful. It is also used following bone marrow transplant to evaluate the new marrow's cell production
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#36
30.EE
Eukaryotes have three nuclear RNA polymerases, each with distinct roles and properties:

Name transcribed
RNA Polymerase I (Pol I, Pol A) nucleolus Larger ribosomal RNA (rRNA) (28S, 18S, 5.8S)
RNA Polymerase II (Pol II, Pol B) nucleus messenger RNA (mRNA) and most small nuclear RNAs (snRNAs)
RNA Polymerase III (Pol III, Pol C) nucleus (and possibly the nucleolus-nucleoplasm interface) transfer RNA (tRNA) and other small RNAs (including the

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#37
31.AA

Metabolic acidosis.To distinguish between the main types of metabolic acidosis, a clinical tool called the anion gap is considered very useful. It is calculated by subtracting the chloride and bicarbonate levels from the sodium.

Anion gap = ( [Na+] ) - ( [Cl-]+[HCO3-] )

High anion gap metabolic acidosis
Causes include:

lactic acidosis
ketoacidosis
chronic renal failure (accumulation of sulfates, phosphates, urea)
intoxication:
organic acids (salicylates, ethanol, methanol, formaldehyde, ethylene glycol, paraldehyde, INH)
sulfates, metformin (Glucophage)
massive rhabdomyolysis
Normal anion gapMain article: Normal anion gap acidosis
Causes include:

longstanding diarrhea (bicarbonate loss)
pancreatic fistula
uretero-sigmoidostomy
Renal tubular acidosis (RTA)
intoxication:
ammonium chloride
acetazolamide (Diamox)
bile acid sequestrants
isopropyl alcohol
renal failure (occasionally)
Glue sniffing
toluene
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#38
32.AA

http://www.youtube.com/watch?v=EYGrElVyHnU

33.BB
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#39
34.EE

India ink test
A diagnostic test used to detect the cryptococcal organism C. neoformans. A dye, called India ink, is added to a sample of CSF fluid, and if the fungi is present, they will become visible as the dye binds to the capsule surrounding the fungus.

Detection of cryptococcal antigen (capsular material) by culture of CSF, sputum and urine provides definitive diagnosis
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#40
35.AA
Strepto. Pneumonia is Gram-positive, alpha-hemolytic, bile-soluble aerotolerant, anaerobic member of the genus Streptococcus.
Despite the name, the organism causes many types of pneumococcal infections other than pneumonia, including acute sinusitis, otitis media, meningitis, bacteremia, sepsis, osteomyelitis, septic arthritis, endocarditis, peritonitis, pericarditis, cellulitis, and brain abscess.

Pneumococcal pneumonia is more common in the very young and the very old.
S. pneumoniae can be differentiated from Streptococcus viridans, some of which are also alpha-hemolytic, using an optochin test, as S. pneumoniae is optochin-sensitive. S. pneumoniae can also be distinguished based on its sensitivity to lysis by bile



They have a polysaccharide capsule that acts as a virulence factor for the organism;
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