Search PubMed⌕ Search

Biomedical subjects

A Krishna

Publications and source records attributed to A Krishna.

At least 37 records · Page 2Linked to original sources
PubMed1998

Ovarian androstenedione production is enhanced by insulin during the period of delayed ovulation in a vespertilionid bat, Scotophilus heathi.

The aim of the present study was to evaluate the role of insulin in the production of high concentrations of androstenedione in the ovary of Scotophilus heathi during the period of delayed ovulation. The concentrations of serum insulin were found to be high during November and December and declined significantly before ovulation. A significant correlation was observed between circulating insulin concentration and body weight as well as with serum androstenedione concentrations. Autoradiographic study demonstrated specific accumulation of 125I-labelled insulin in the ovarian thecal and interstitial cells. Insulin increased both basal and hCG-stimulated androstenedione production by the ovary in vitro during November. These results indicate that insulin may be involved in inducing high androstenedione synthesis by the ovary and thus may be indirectly responsible for inducing delayed ovulation in S. heathi.

Androstenedione↗
PubMed1998

Immunolocalization of cytochrome P450 side chain cleavage, 17-alpha-hydroxylase and aromatase in the ovary of vespertilionid bat (Scotophilus heathi) during different phases of ovulatory delay.

Immunocytochemical localization of steroidogenic enzymes, cytochrome P450 side chain cleavage, 17-alpha-hydroxylase and aromatase, was performed in the ovaries of Scotophilus heathi during reproductive cycle, with reference to the period of delayed ovulation. Moderate immunoreactivity of side chain cleavage enzyme and 17-alpha-hydroxylase was observed mainly in thecal cells and interstitial cells of the ovarian stroma during quiescence. Thecal cells positive for 17-alpha-hydroxylase were found even around the primary follicles. The peak immunoreactivity for all the three enzymes was observed during recrudescence. It coincided with high circulating steroid levels during this period. In the stroma, immunoreactivity for side chain cleavage and 17-alpha-hydroxylase was so extensive that it almost occupied the entire interfollicular area of the ovary. Aromatase immunoreactivity declined, but side chain cleavage enzyme and 17-alpha-hydroxylase remained extensive during the period of delayed ovulation. This suggests a high androgen and low estrogen synthesis during the period of delayed ovulation. There was a marked decline in 17-alpha-hydroxylase and an increase in aromatase immunoreactivity during the preovulatory period, suggesting a decrease in androgen and increase in estrogen synthesis. The results suggest thecal cells and interstitial cells of the stroma as the major site of steroidogenesis in the ovary of S. heathi. Over production of androgen is attributed to the extensive development of 17-alpha-hydroxylase positive interstitial cells in the ovarian stroma, and this may be responsible for delayed ovulation in Scotophilus heathi.

Animals↗
PubMed1997

Clinical and angiographic findings in black patients with suspected coronary artery disease.

To determine the clinical variables and coronary angiographic findings in black patients with suspected coronary artery disease, we analyzed the data on consecutive black patients undergoing their first coronary angiogram over a three year period at the Cook County Hospital, Chicago, Illinois. We compared these findings to those of black and white patients from previous studies. There were 654 patients with a mean age+/-standard deviation of 56+/-10 years; 309 (47%) were men. Two hundred nineteen patients (33%) presented with unstable angina, 75 patients (12%) with acute myocardial infarction and 338 patients (52%) with chronic stable angina. Three hundred forty-six patients (53%) had 50% or greater stenosis in at least one of the major vessels. Among the patients with coronary artery disease, 128 patients (37%) had one vessel disease, 102 patients (29%) had two-vessel disease, and 116 patients (34%) had three-vessel disease. Black patients who undergo coronary angiography for suspected coronary artery disease have a high frequency of normal coronary angiogram or non-obstructive coronary artery disease. The frequency of 1-, 2- and 3-vessel disease in blacks with coronary artery disease is comparable to those observed in whites in previous reports.

Adult↗
PubMed1997

Adiposity and androstenedione production in relation to delayed ovulation in the Indian bat, Scotophilus heathi.

Observations on body weight, circulating androstenedione concentrations and morphology of ovarian stroma were made in Scotophilus heathi during the period of delayed ovulation to make a comparison with polycystic ovarian syndrome in women. Body weight of bats increased from a level of 31.00 +/- 0.30 g in August and reached a peak of 45.00 +/- 0.46 g in November. This increase in body weight was due to accumulation of adipose tissue. The body weight declined gradually from December onwards and finally reached a basal level in March. The circulating androstenedione concentration showed a gradual increase from 36.80 +/- 15.54 ng/ml in August and reached a peak level of 220.50 +/- 50.10 ng/ml in November. Androstenedione concentration reached the lowest level in the March, just before ovulation. Morphological study showed extensive distribution of luteinized stromal cells or interstitial cells (ICs). Morphometric study showed that during the period of ovulatory delay, more than 75% area of the ovary was occupied by the ICs. Hyperandrogenism, anovulation, obesity (fat deposition) and stromal hyperthecosis present during delayed ovulation in S. heathi may serve as an experimental model for some aspects of the polycystic ovarian condition in women.

Adipose Tissue↗
PubMed1997

Congenital Y-type urethro-perineal fistula.

A case of congenital fistula between the prostatic urethra and the perineal skin in a ten-months-old male child is reported. The fistula was lined by squamous epithelium. The precise embryological origin of this fistulous communication remains controversial. We believe that this anomaly is distinct from the congenital H-type urethro-anorectal fistula.

Cutaneous Fistula↗
PubMed1997

Twin flap technique for nipple reconstruction.

A technique of nipple reconstruction using two local flaps is described. The central 'core' flap is surrounded by a peripheral 'wrap' flap, producing a natural nipple. Results of 24 nipple reconstructions in 22 cases are presented. This technique is useful when the neo-nipple location falls on the mastectomy scar.

Breast Implants↗
PubMed1997

The effect of line configuration on perceived numerosity of dotted lines.

Estimates the number of objects in a line are made in many different situations. This paper demonstrates that besides the actual number of dots, aspects of line configuration affect the perceived numerosity of dotted lines. Experiment 1 provides evidence that the highly studied "clutter effect" in distance perception research replicates to the numerosity domain so that lines made up of more segments are perceived to contain more dots. Experiments 2-5 provide nomological validity for the recently proposed "direct distance" effect in distance perceptions by showing that numerosity perceptions are higher the greater the euclidean length between the line end points and by manipulating euclidean length in three orthogonal ways: the relative length of segments (Experiment 2), the angle between segments (Experiment 3), and the general direction of segments (Experiment 4). Experiment 5 conceptually replicates the results of Experiments 2-4 utilizing stimuli-based versus memory-based judgments and a discrimination task. Experiments 6 and 7 extend the research on spatial perception by demonstrating that the use of euclidean length as a source of information is inversely related to line width, with width varied through clutter (Experiment 6) and total line length (Experiment 7). Overall, the results demonstrate that the robustness of the euclidean length effect is contingent on the salience of alternative spatial heuristics--specifically, euclidean width. Theoretical implications are discussed.

Humans↗
PubMed1997

The relationship between spermatozoa and epithelium of the female genital tract during sperm storage in the greater yellow bats (Scotophilus heathi): the light and electronmicroscopic observations.

The present paper describes the relationship between spermatozoa and the epithelium of the female genital tract during sperm storage in greater yellow bats, Scotophilus heathi. All the female bats collected from mid-January till ovulation in early March showed the presence of spermatozoa with their heads orientated towards the epithelial lining of the female genital tract. During this period, the epithelial cells of the uterine horn showed extensive endoplasmic reticulum (ER), numerous mitochondria and well developed Golgi complexes. In females inseminated during December, the spermatozoa were not arranged linearly and showed signs of degeneration. During December, the uterine epithelial cells contained only a few small mitochondria and less developed rough ER. The leucocytes and Langerhans cells were frequently seen in the epithelial lining during the course of sperm storage especially at the site of phagocytised sperm heads.

Animals↗
PubMed1997

Pulmonary agenesis.

Explore the source record for details and available documents.

Abnormalities, Multiple↗
PubMed1997

Goldenhar syndrome.

Explore the source record for details and available documents.

Child, Preschool↗