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NBME#2 block 1 Q1-----------Q50 - maryam2009
#41
sorry maryam2009 and drona99
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#42
lolSmilenice
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#43
so, who's next?
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#44
its ok anyways we all added different points so no worries and anyways we all shud know abt itSmile
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#45
it is very nice ,different explanations Smile
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#46
33. B.

Lipid peroxidation is the mechanism for free radical injury.

Free radical injury is also seen in Doxorubicin treatment, Heavy metal toxicity (child with iron overdose ingestion) n many others ..
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#47
sorry i missed one q.

32. A.
CD4 is activated -> long lasting immunity.

B cell can be activated directly by polysaccharide and lipopolysacharide but that would result in short immunity n won't be effective esp. in children.

H. influenza, Strep Pneumonia (children) vaccines are capsular polysaccharide + protein substrate whereas Strep Pneumonia (adults), N. meningitides are just polysaccharide (stimulate previously existing reactive cells).
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#48
32- AA
polysaccharide outer coats that are poorly immunogenic. By linking these outer coats to proteins (e.g. toxins), the immune system can be led to recognize the polysaccharide as if it were a protein antigen.
Now this protein was 1st presented to MHC classII through B lymphocytes these lymphocytes now come in contact with Helper T cells or CD4 cells
Cd4 cells get activated through
1-B7-CD 28
2-Cd40/Cd40L
acivated T cells release cytokines IL2;IL4;IL5
These cytokines further differentiates B cells and class switching and memory occurs .Thus we are producing antibodies ie strong immunity against H influenza through vaccine.
anymore suggestion on these q plz post .i think its a one of the crucial concept
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#49
33 agrre with barcelone
bb
Definition of free radicals -
Compounds with a single unpaired electron in an outer orbital
Degrade nucleic acids and membrane molecules
DNA fragmentation and dissolution
Lipid peroxidation of polyunsaturated lipids in cell membranes


Types of free radicals

O2-derived free radicals
Superoxides

Hydroxyl ions (OH)
Peroxides (H2O2)
Drug and chemical free radicals
Free radicals are produced in the liver cytochrome P-450 system.
Examples include acetaminophen and carbon tetrachloride



Neutralization of free radicals
1-Superoxide dismutase neutralizes superoxide free radicals.
2-Glutathione peroxidase (enhances glutathione) neutralizes peroxide, hydroxyl, and acetaminophen free radicals.
3-Catalase neutralizes peroxide free radicals.
4-Vitamin antioxidants (ascorbic acid, vitamin E, β-carotenes) block the formation of free radicals and degrade free radicals
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#50
34- Diabetic ketoacidosis -=cc
In diabetes we have insulin defiency and its deficiency results in to increase in activity of HSL and
2-also due to lack insulin there will be no check on glucagone


mech Hyperglycemia in DKA--
A--Increased gluconeogenesis
Due to increase in glucagon and epinephrine
Most important mechanism of hyperglycemia
B--Increased glycogenolysis in the liver

Mech of ketoacidosis
Normally insulin inhibits HSL ie harmone sensitive lipase but as insulin is absent HSL gets activated it leads to fatty acid oxidation

Increased β-oxidation of fatty acids increases production of acetyl CoA.

Acetyl CoA is converted by the liver to ketone bodies.
Acetone (fruity odor), acetoacetic and β-hydroxybutyric acid


** Beta oxidation is prevented by malonyl Co-A which inhibit carnitine acyltransferase, the rate-limiting enzyme of β-oxidation .

Insulin by activating acetyl co A carboxylase increases fatty acid synthesis and increases malonyl co A concentration ..but as insulin is absent in DKA ..this doesnt occure which results in excess fatty acid beta oxidation and ketone body formation .
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