Search PubMed⌕ Search

Biomedical subjects

R K Mittal

Publications and source records attributed to R K Mittal.

83 records · Page 5Linked to original sources

Incidence of the metopic suture in adult Nigerian skulls.

This study was carried out on 206 adult Nigerian skulls for the incidence of the metopic suture. Metopism was present in 3.4% of cases, and a metopic suture (complete or incomplete) was observed in 34.97% of the skulls. The metopic suture was present in the lower part of the frontal bone, in various shapes, in 30.10% of cases. The most common shape observed was linear type (24.27%). Inverted U-shaped, and wide side to side excursion, were found in 0.49% of cases of each kind, these being the least common form of the suture. The incidence in the upper, upper middle and lower middle parts of the frontal bone was 0.49% in each type.

Adult↗

Effect of centrally administered glucagon on urine output in dogs.

The effect of minimal doses of glucagon, administered by intracerebroventricular (ICV) and intracisternal(IC) routes, on urine output in mongrel dogs have been studied. The dose of 2.0 mug of glucagon was found to be the minimal dose for diuresis on peripheral administration. This dose when centrally administered, produced an oliguric effect in animals. This effect was not observed in vagosympathectomised-spinal cord transectomised or adrenalectomised animals. It is suggested that the probable efferents might be the sympathetic fibres as they are present in vagi nerves as well in the spinal cord (26). The observations made in an attempt to find out the organ responsible for the oliguric effect, showed that some substance released from the adrenal cortex has an influence on the kidney's excretory function.

Adrenal Cortex↗

Hypocholesterolemic response to angiotensin II in dogs.

Intravenous administration of angiotensin II caused a significant decrease in blood choelsterol level in dogs. This hypocholesterolaemic response, also obtained in spinal vagotomized and adrenalectomized dogs, indicates that central nervous system and adrenals have no role in angiotension II induced hypocholesterolemic effect. In hepatectomized dogs in which both vagi were intact intravenously administered angiotensin did not cause any significant decrease in blood choelsterol level, suggesting that angiotensin exerts its effect by inhibiting the synthesis or preventing the release of cholesterol from the liver.

Adrenalectomy↗

Effect of centrally administered insulin on blood glucose levels in dogs.

The effects of minimal doses of insulin administered by intracerebroventricular (ICV) and intracisternal (IC) routes in mongrel dogs, on peripheral blood glucose level (BGL) have been studied. The dose of 0.1 U of insulin was found to be the minimal dose. This dose produced an immediate short lived hyperglycaemia followed by a marked and sustained hypoglycaemia. Both the effects were not observed in spinal cord transected-vagosympathectomised animals. The immediate hyperglycaemic effect was not observed in adrenalectomised animals whereas the subsequent hypoglycaemic effect did not appear only when the liver was removed. In an attempt to identify the precise site of action in the central nervous system (CNS), The cerebellomedullary angles were found to be the most sensitive sites for the action of locally applied insulin. It is suggested that insulin on central administration causes a rise in the BGL by an action on the adrenal glands and subsequently causes a marked fall in BGL by an action on the liver through some nerve fibers.

Adrenalectomy↗

Effects of designs of Class 2 preparations on resistance of teeth to fracture.

This study was designed to evaluate the effect of isthmus width on the strength of the remaining tooth structure in maxillary first premolars restored with class 2 silver amalgam restorations. One hundred ten sound maxillary first premolars freshly extracted as a part of orthodontic treatment were collected. The teeth were then divided into 10 groups of 11 teeth each. Ideal class 2 mesio-occlusal, disto-occlusal and mesio-occlusodistal cavities with different isthmus widths i.e. one half the intercuspal distance, one third the intercuspal distance and one fourth the intercuspal distance and one fourth the intercuspal distance were prepared. Compressive forces were applied using a Universal Testing Machine and load to the point of fracture was determined. Intact teeth produced the best tooth fracture resistance i.e. 105.4 MPa, followed by preparations with isthmus width of one fourth, one third and one half intercuspal distance in the order.

Bicuspid↗

Role of catecholamines in angiotensin induced hyperglycaemia.

The effects of angiotensin II were studied on blood sugar level in dogs. Intracerebroventricular administration of pressor dose of angiotensin caused a rise in blood sugar level. The hyperglycaemia and pressor response was not affected by bilateral vagotomy and was less marked in adrenalectomized dogs. The hyperglycaemic effect and pressor response was not observed in reserpinized and spinal vagotomized dogs. It is suggested that centrally administered angiotensin stimulates the hypothalamic or medullary accelerator neurons (central sympathetic structures) to cause a marked release of catecholamines from peripheral stores specially adrenal medulla. This excessive release of catecholamines is responsible for hyperglycaemia and pressor response of angiotensin II in dogs.

Adrenal Glands↗