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1- A homeless person has been brought to emergency. Blood biochemistry reveals highf lactate levels. An impaired activity of PDH complex is suspected. Which vitamin deficiency can cause such symptoms ?

Answer- It is a case of thiamine (B1) deficiency. PDH complex catalyzes the conversion of Pyruvate to Acetyl co A . The multienzyme complex requires the presence of thiamine, lipoic acid, pantothenic acid, riboflavin and niacin. A deficiency of thiamine (TPP- active form) which is very common in alcoholics usually presents with lactic acidosis. Due to impaired activity of PDH complex alternatively pyruvate is converted to lactate causing lactic acidosis.

2. A 22-year-old female has presented with seborrheic dermatitis. Blood biochemistry reveals reduced activity of Glutathione reductase enzyme. Which vitamin deficiency is suspected in this patient ?

Answer- It is a case of Riboflavin (B2) deficiency.  Riboflavin is essential for healthy skin, nails, hair growth and general good health. Characteristic symptoms of riboflavin deficiency include lesions of the skin, especially in the corners of the mouth, and a red, sore tongue. Assessment of Riboflavin status can be done by erythrocyte glutathione reductase activity.

3.What would be the clinical outcome if vitamin C is deficient?

Answer- Vitamin C deficiency can occur as part of general under nutrition, but severe deficiency (causing scurvy) is uncommon. Symptoms include fatigue, depression, and connective tissue defects (eg, gingivitis, petechiae, rash, internal bleeding, impaired wound healing). In infants and children, bone growth may be impaired. Severe deficiency results in scurvy, a disorder characterized by hemorrhagic manifestations and abnormal osteoid and dentin formation. Diagnosis is usually clinical. Treatment consists of oral vitamin C

4.- Name a confirmatory test to diagnose underlying Thiamine deficiency.

Answer- R.B.C Transketolase activity and 24-h urinary thiamine excretion may be measured  to diagnose underlying thiamine deficiency.

5 – Which vitamin is known to participate in the Carboxylation reactions?

Answer- Biotin participates in the carboxylation reactions. The enzymes like Pyruvate carboxylase, Acetyl  co A carboxylase and Propionyl co A carboxylase require Biotin as a coenzyme. These carboxylation reactions require CO2 and ATP as a source of energy.

6- What is the active form of vitamin B6?

Answer- Vitamin B6, also called pyridoxine is active in the pyridoxal-phosphate form. There are six forms of vitamin B6: pyridoxal (PL), pyridoxine (PN), pyridoxamine (PM), and their phosphate derivatives: pyridoxal 5′-phosphate (PLP), pyridoxine 5′-phosphate (PNP), and pridoxamine 5′-phospate (PNP). PLP is the active coenzyme form, and has the most importance in human metabolism.

7- Which vitamin deficiency is associated with Burning feet syndrome?

Answer- Mostly deficiency of Pantothenic acid is associated with burning feet syndrome.

8- Name a folate antagonist used as an anticancer drug.

Answer- Methotrexate , a folate antagonist is used as an anticancer drug. Methotrexate, an analog of 10-methyl-tetrahydrofolate, inhibits dihydrofolate reductase and has been exploited as an anti-cancer drug. Methotrexate blocks the cell’s ability to regenerate THF, leading to inhibition of these biosynthetic pathways.The lack of nucleotides prevents DNA synthesis, and these cancer cells cannot divide without DNA synthesis.

9-Which vitamin is known to participate in the hydroxylation reactions?

Answer- Vitamin C, also known as ascorbic acid participates in the hydroxylation reactions. Vitamin C  is the coenzyme for two groups of hydroxylases. These are copper-containing hydroxylases and the α -ketoglutarate-linked iron-containing hydroxylases.

10-Name the vitamins, the deficiencies of which can be manifested as megaloblastic anemia.

Answer- Both folate and cobalamine deficiencies have similar megaloblastic  anemia and GI symptoms. However, cobalamine deficiency also can present with numerous neurologic manifestations including: numbness, paresthesias, weakness, ataxia, abnormal reflexes and diminished vibratory sensation.

11- Which vitamin deficiency would be precipitated by a complete vegetarian diet?

Answer- Since vitamin B12 is present in all foods of animal origin, dietary vitamin B12 deficiency is extremely rare and is seen only in vegans—strict vegetarians who avoid all dairy products as well as meat and fish

12- Which vitamin deficiency would be precipitated by a complete non vegetarian diet?

Answer- Folic acid and vitamin C deficiencies are expected in persons with a complete non vegetarian dietary pattern  as these vitamins are mostly of plant origin.

13- New born infants exposed to blue light for phototherapy generally develop Riboflavin deficiency, suggest the reason for it.

Answer- Riboflavin is sensitive to light and becomes inactive upon exposure that is why deficiency is precipitated.

14- Which vitamin deficiency is known to cause bleeding gums?

Answer- Vitamin C deficiency causes bleeding gums. Gums may become swollen, purple, spongy, and friable; they bleed easily in severe deficiency.

15- Name a vitamin which is used therapeutically as a lipid lowering drug

Answer- Niacin reduces plasma triglyceride and LDLc levels and raises the plasma concentration of HDLc. Niacin is also the only currently available lipid-lowering drug that significantly reduces plasma levels of Lp (a). If properly prescribed and monitored, niacin is a safe and effective lipid-lowering agent.


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