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DNA - Basic structure

Parts of DNA Phosphate group + sugar + Base (nitrogenous base) Difference between sugar of DNA and RNA DNA has deoxyribose sugar(1 OH group attached to sugar and RNA has ribose sugar (2 OH groups) Nucleotide and nucleoside Nucleotide = Phosphate group + Base + sugar Nucleoside = Base and sugar Types of Nitrogenous base Purines and Pyrimidines Purines consists of Pure As Gold = Adenine and Guanine Pyrimidine consists of CUT the pyramids Cytosine Uracil (only in RNA) Thymine Purine nucleosides are Adenosine and Guanosine Pyrimidine nucleosides are Cytidine, Uridine and Thymidine Purine nucleotides Adenosine monophosphate, Guanosine MP How is DNA packed inside nucleus ? In the form of chromatin which is further condensed to form chromosomes What is a nucleosome ? DNA coiled twice around an octamer of Histone composed of (H2A, H2B, H3, H4) x2 with linker H1 protein. Positive and Negative charge of Chromatin Positive charged = Lysine and Arginine of Histone which bind to negative char

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Treatment of Wilson disease

What is the aim of treatment of Wilson disease? Removal or copper deposited in various organ and Prevention of reaccumulating. Along with the pharmacological therapy people with Wilson disease should reduce the consumption of Copper containing food items. For Clinical features and diagnosis of Wilson Disease First introduced in 1956 AD and still the standard of treatment. How does it act? The sulfhydryl group in d-penicillamine chelates copper removes the copper from the tissue and out of the body via urinary excretion. It can also induce the endogenous hepatic metallothionein, a cytosolic metal-binding protein, which sequesters copper and thereby limiting damage to the liver. How penicillamine is absorbed? Its absorption is decreased by as much as 50 percent when taken with food. Thus, it should be taken 1 hour before or 2 hours after meal. What is the dose of D-penicillamine? The drug is introduced at a dose of 250 to 500 mg/day and then increased by 250 mg every 4 t

WILSON DISEASE

Aka Hepatolenticular degeneration Autosomal Recessive inheritance What is the defect in Wilson disease? Basic defect in hepatocellular copper transport, leading to the accumulation of copper in the liver and other tissues, including the brain. ATP7B is a copper-transporting intracellular protein affected in Wilson disease. ATP7B is expressed mainly in hepatocytes. This defect leads to reduced incorporation of copper into apo ceruloplasmin and decreased transport of copper from the liver into bile, leading to copper excess in tissue. Although the ceruloplasmin levels are diagnostic in Wilson disease it does not play any significant role in the disease pathogenesis. Note: Hereditary aceruloplasminemia is a disease condition characterized by iron deposition in tissues and not copper How copper deposition occurs in other tissues? Once the hepatocytes are filled with copper this leads to injury thus liberating the copper in circulation which leads to extrahepatic copper deposition.

VACTERL/VATER ASSOCIATION

Why not syndrome and why association? VATER or VACTERL is not a syndrome as there is a no single pathological cause responsible for the common incidence. Components of VACTERL are V - Vertebral anomalies occur in 80 t0 85% cases - hemivertebrae or hypoplastic vertebrae A - Anal atresia or imperforate anus occur in 50-55% cases C - cardiac malformations occur in 75% cases VSD, ASD and ToF are common TE - tracheoesophageal fistula with esophageal atresia occur in 70% cases Renal anomalies renal anomalies occur in 50% cases like agenesis or dysgenesis, single umbilical artery can also occur Limb anomalies Radial anomalies like radial aplasia, hypoplastic thumbs can occur. Syndactyly, polydactyly can also occur.

Gitelman

Autosomal Recessive condition More common than Bartter syndrome Mimics chronic thiazide therapy side effects It affects Na-Cl channel of Distal convoluted tubule Characterized by Polyuria Metabolic alkalosis Hypokalemia Hyponatremia Hypomagnesaemia Low blood pressure Pathophysiology of these features are similar to Bartter syndrome For Bartter notes How is Gitelman syndrome different from Bartter syndrome? Bartter syndrome show poor response to a loop diuretic, while patients with Gitelman syndrome have poor response to a thiazide diuretic. Concentrating ability is impaired in Bartter syndrome but is relatively preserved in Gitelman syndrome since LoH is more concerned with generating concentration gradient in kidney. Urinary calcium excretion is typically reduced in patients with Gitelman syndrome as it is with a thiazide diuretic but high in Bartter syndrome. Treatment is similar to Bartter syndrome.