The diameter of the tip of a periodontal probe is:

 # The diameter of the tip of a periodontal probe is:

A. 0.25 mm

B. 0.5 mm

C. 0.75 mm

D. 1 mm

The correct answer is B. 0.5 mm.

Periodontal probes are used to measure the depth of pockets and to determine their configuration. The typical probe is a tapered, rodlike instrument calibrated in millimeters, with a blunt, rounded tip. There are several other designs with various millimeter calibrations. The World Health Organization (WHO) probe has millimeter markings and a small, round ball at the tip. Ideally, these probes are thin, and the shank is angled to allow easy insertion into the pocket. Furcation areas can best be evaluated with the curved, blunt Nabers probe. When measuring a pocket, the probe is inserted with a firm, gentle pressure to the bottom of the pocket. The shank should be aligned with the long axis of the tooth surface to be probed. Several measurements are made to determine the level of attachment along the surface of the tooth.

Reference: Carranza's Clinical Periodontology 12th edition.

Which of the following may create gingival deformities that require gingivoplasty to eliminate the defects?

 # Which of the following may create gingival deformities that require gingivoplasty to eliminate the defects?

A. Erosive linchen planus 

B. Desquamative gingivitis 

C. Acute herpetic gingivostomatitis 

D. Necrotising ulcerative gingivitis 

The correct answer is D. Necrotising ulcerative gingivitis.

■ Shelf-like gingival margins after healing may result in plaque accumulation. 

■ The gingiva is reshaped with periodontal knife or with electrosurgery. This process of eliminating the defects by reshaping is called as gingivoplasty. 

■ Gingival deformities are seen in gingival disease:  (Asked in AIIMS 1999) (ANUG) 

Surgical procedure for severe tissue destruction in ANUG infection is:  (Asked in COMED 2011) (Reshaping the gingiva, Gingivoplasty) 

Site of Antidiuretic hormone (ADH) action is:

 # Site of Antidiuretic hormone (ADH) action is:

A. Proximal tubule

B. Loop of Henle

C. Vasa recta

D. Collecting tubule

The correct answer is D. Collecting tubule.

Human vasopressin, also called antidiuretic hormone (ADH), arginine vasopressin (AVP) or argipressin, is a hormone synthesized from the AVP gene as a peptide prohormone in neurons in the hypothalamus, and is converted to AVP. It then travels down the axon terminating in the posterior pituitary, and is released from vesicles into the circulation in response to extracellular fluid hypertonicity (hyperosmolality). AVP has two primary functions. First, it increases the amount of solute-free water reabsorbed back into the circulation from the filtrate in the kidney tubules of the nephrons. Second, AVP constricts arterioles, which increases peripheral vascular resistance and raises arterial blood pressure.

Acute increase of sodium absorption across the ascending loop of Henle. This adds to the countercurrent multiplication which aids in proper water reabsorption later in the distal tubule and collecting duct.

Pyruvate dehydrogenase complex contains all EXCEPT:

 # Pyruvate dehydrogenase complex contains all EXCEPT:

A. Biotin

B. NAD

C. FAD

D. Co-A

The correct answer is A. Biotin.

Pyruvate dehydrogenase complex (PDC) is a complex of three enzymes that converts pyruvate into acetyl-CoA by a process called pyruvate decarboxylation. Acetyl-CoA may then be used in the citric acid cycle to carry out cellular respiration, and this complex links the glycolysis metabolic pathway to the citric acid cycle. Pyruvate decarboxylation is also known as the "pyruvate dehydrogenase reaction" because it also involves the oxidation of pyruvate.

The enzymes involved in PDC are Pyruvate dehydrogenase (E1), Dihydrolipoyl transacetylase (E2), and Dihydrolipoyl dehydrogenase (E3). The cofactors involved are: TPP (thiamine pyrophosphate), magnesium, lipoate, coenzyme A, FAD and NAD+. 

Reference: https://en.wikipedia.org/wiki/Pyruvate_dehydrogenase_complex