Liver as a hub of cholesterol metabolism All nucleated cells have the capacity to synthesize cholesterol from acetyl-CoA (like most biological lipids). 90% of synthesis occurs in liver and intestine. The cholesterol biosynthesis pathway involves enzymes that are in the cytoplasm, microsomes (ER), and peroxisomes. Liver obtains cholesterol from 3…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Lipoprotein Metabolism Simplified
Lipoproteins Composition of Lipoproteins: Non-polar core – mainly triglycerides and cholesteryl esters Single surface layer – amphipathic phospholipids and cholesterol Apoprotein or Apolipoprotein Class Abbreviation Density Protein Lipid content Electrophoretic mobility Chylomicrons CM lowest lowest highest (exogenous triacylglycerol) don’t migrate Very low density lipoproteins VLDL .. .. .. (endogenous triacylglycerol)…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Neutropenic Fever and Empiric Therapy
Synonym: Febrile Neutropenia Definition of Neutropenic Fever Fever: Single oral temperature ≥ 38.3 °c (101 °F) or ≥ 38 °c (100.4 °F) sustained over 1 hour Neutropenia: Absolute Neutrophil Count (ANC) <500 cells/cu.mm or ANC expected to fall <500/cu.mm in next 48 hours Profound neutropenia: ANC <100/cu.mm Prolonged neutropenia: Neutropenia for >7 days…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Bronchogenic Carcinoma Etiopathogenesis
INCIDENCE Male > Female Age group: 50-75 years Second highest cancer in both sexes after prostate (male) and breast (female) Smokers > Non-smokers ETIOLOGY OF LUNG CANCER A. Cigarette smoking: Smoking is the single most important risk factor for lung cancer, which can cause all types of lung cancer but…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Inheritance of Disease – Mnemonics
Lets work with some generalizations 1. X-linked dominant, mitochondrial and Y-linked conditions are rare. You need to remember them. 2. Usually inherited in autosomal dominant pattern are: Mostly mutations in non-enzymatic structural proteins (e.g. collagen, fibrillin, cytoskeletal proteins of RBC) or in membrane receptors (e.g. LDL receptor) Diseases due to diminished…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Polymerase Chain Reaction (PCR) Made Easy
What is Polymerase Chain Reaction ? It is a process of artificial DNA replication (amplification of a selected part of DNA). As the name suggests: Polymerase: It requires DNA polymerase for extending the added primers to complete DNA replication. Chain Reaction: PCR is run in cycles. The number of molecules…
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Why to not defibrillate Asystole ?
What is asystole? Asystole is a state of no cardiac electrical activity. It is seen as a “flat-line” in ECG monitor. However, other possible causes of flat-line should be ruled out before calling it asystole. They are: Loose or disconnected ECG leads Loss of power to ECG monitor Once, asystole…
PGMEE, MRCS, USMLE, MBBS, MD/MS 
Leukocyte Adhesion Cascade and Defect : Simplified
Capture or Tethering Increased vascular permeability and vasodilation are mediated by inflammatory mediators like histamine released by inflammatory cells in response to PAMPs expressed by pathogens. Hemoconcentration (owing to increased vascular permeability) and decreased velocity of blood flow (owing to vasodilation) leads to peripheral pooling of the leukocytes (i.e. towards…