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Biomedical subjects

A Krishna

Publications and source records attributed to A Krishna.

At least 19 recordsLinked to original sources
PubMed2005

Histochemical localization of enzymes and lipids in the ovary of a vespertilionid bat, Scotophilus heathi, during the reproductive cycle.

The present study describes seasonal changes in delta5 3beta hydroxysteroid dehydrogenase (3beta-HSD), glusose-6 phosphates dehydrogenase (G-6-PD), and lipids in the ovary of a vespertilionid bat, Scotophilus heathi. Total lipids and 3beta-HSD activity are restricted to thecal and interstitial cells of the ovary. The total lipids, 3beta-HSD, and G-6-PD significantly increase during recrudescence, and remain high during winter dormancy and breeding as compared to the other reproductive phases. High incidence of lipids and enzyme activity in interstitial cells during the breeding period and at the time of ovulation clearly suggests that these cells are actively involved in steroidogenesis. A decline in enzymes and lipid activity during winter dormancy, which correlates with the declining levels of steroidogenesis, might be the factors responsible for prolonged survival of the Graafian follicle in the ovary of S. heathi.

3-Hydroxysteroid Dehydrogenases↗
PubMed2004

Effects of metformin treatment on luteal phase progesterone concentration in polycystic ovary syndrome.

The causes of luteal phase progesterone deficiency in polycystic ovary syndrome (PCOS) are not known. To determine the possible involvement of hyperinsulinemia in luteal phase progesterone deficiency in women with PCOS, we examined the relationship between progesterone, luteinizing hormone (LH) and insulin during the luteal phase and studied the effect of metformin on luteal progesterone levels in PCOS. Patients with PCOS (19 women aged 18-35 years) were treated with metformin (500 mg three times daily) for 4 weeks prior to the test cycle and throughout the study period, and submitted to ovulation induction with clomiphene citrate. Blood samples were collected from control (N = 5, same age range as PCOS women) and PCOS women during the late follicular (one sample) and luteal (3 samples) phases and LH, insulin and progesterone concentrations were determined. Results were analyzed by one-way analysis of variance (ANOVA), Duncan's test and Karl Pearson's coefficient of correlation (r). The endocrine study showed low progesterone level (4.9 ng/ml) during luteal phase in the PCOS women as compared with control (21.6 ng/ml). A significant negative correlation was observed between insulin and progesterone (r = -0.60; P < 0.01) and between progesterone and LH (r = -0.56; P < 0.05) concentrations, and a positive correlation (r = 0.83; P < 0.001) was observed between LH and insulin. The study further demonstrated a significant enhancement in luteal progesterone concentration (16.97 ng/ml) in PCOS women treated with metformin. The results suggest that hyperinsulinemia/insulin resistance may be responsible for low progesterone levels during the luteal phase in PCOS. The luteal progesterone level may be enhanced in PCOS by decreasing insulin secretion with metformin.

Adolescent↗
PubMed2002

Seasonal changes in circulating steroid concentration and their correlation with the ovarian activity in the female Indian sheath-tailed bat, Taphozous longimanus.

The relationship between ovarian activity and circulating steroid concentration was studied in the female sheath-tailed bat, Taphozous longimanus. T. longimanus breeds twice in rapid succession during the year at Varanasi, India. Ovarian recrudescence was observed during September, and antral follicles were first observed during the month of October. Circulating androstenedione concentration showed an increase beginning in October, reaching a peak in December. This increase in androstenedione concentration correlated with the period of heavy accumulation of adipose tissue and increase in body mass. Antral follicles grow slowly during the period of high circulating androstenedione concentration from October to December. There was a sharp decline in androstenedione concentration during January. Simultaneously with the decline in androstenedione concentration, a sharp increase in size of the antral follicle and circulating estradiol concentration was noticed. Soon thereafter, one of the follicles ruptures, followed by fertilization and the commencement of the first pregnancy. During the second pregnancy, antral follicles first appeared during late pregnancy in March in the contralateral ovary that lacked the corpus luteum. One follicle developed rapidly and quickly attained a preovulatory stage in April. This is reflected in a sharp increase in estradiol concentration during this period. Ovulation was observed immediately following the first pregnancy in May. During this period, androstenedione concentration remained low. The results of the present study suggest that high androstenedione concentration during October to December (winter dormancy) may be responsible for slow follicular development and delays ovulation in T. longimanus. It is further hypothesized that the geographical variation in reproductive pattern of T. longimanus could be due to variation in the duration of fat storage and associated changes in the androstenedione concentration.

Adaptation, Physiological↗
PubMed2002

Seasonal changes in thyroid activity in the female sheath-tailed bat, Taphozous longimanus (Chiroptera: Emballonuridae).

The present study was designed to investigate changes in thyroid activity during the reproductive cycle in Taphozous longimanus. Thyroid gland showed marked seasonal variation in weight and secretory activity. It was inactive in quiescence and early to mid-winter dormancy and active during recrudescence and breeding period during late winter dormancy. The serum 3,5,3'-triiodothyronine (T3) and thyroxine (T4) concentrations showed significant variation and closely coincided with thyroid activity. The T3 and T4 concentrations were higher in recrudescence, late winter dormancy and minimum in quiescence and initial stages of first pregnancy. The body weight (r = 0.56), ovary weight (r = 0.73), and thyroid weight (r = 0.70) showed correlation with each other and with T3 and T4 concentrations. The correlation between body weight, thyroid weight and T3 and T4 concentrations in non-pregnant bats was higher when compared with pregnant bats. The T3 and T4 levels remained low during the initial stages of development in first pregnancy when compared with the initial stages of second pregnancy. The scant food supply and low levels of T3 and T4 and low temperature during initial stages of first pregnancy might be responsible for differential rate of fetal development in two successive pregnancies in T. longimanus.

Animals↗
PubMed2002

Relationship between corticosterone and body weight, androstenedione and insulin during the period of delayed ovulation in a vespertilionid bat, Scotophilus heathi.

The aim of the present study was to evaluate the relationship between corticosterone, body weight, insulin and androstenedione in order to understand the role of adrenal in contributing hyperandrogenism during delayed ovulation in S. heathi. The circulating corticosterone concentration in female S. heathi showed significant seasonal variation. The peak corticosterone concentration observed during August-September coincides with increased feeding activities in S. heathi. The present study noted a seasonal variation in relationship of corticosterone with insulin and androstenedione in S. heathi. An inverse relationship of corticosterone with insulin and androstenedione was found during August to December, but not during January to May. A seasonal variation in the effect of adrenocorticotropic hormone (ACTH) on adrenal corticosterone production in vitro was observed during reproductive cycle. Corticosterone production in vitro by adrenal declined significantly as compared to the control during quiescence in September. The finding suggests that adrenal attained the peak responsiveness to ACTH during September. ACTH significantly enhanced the androstenedione production by the adrenal in vitro during December, when the circulating androstenedione was also high in S. heathi. This suggests that the adrenal may also contribute to hyperandrogenism during the period of delayed ovulation in S. heathi. Further studies are required to reveal the unique pattern of seasonal relationship between corticosterone, insulin and androstenedione in S. heathi.

Adipose Tissue↗
PubMed2001

Massive pancreatico-pleural effusion--an often unrecognised entity.

Massive haemorrhagic pleural effusion secondary to pancreatitis in a five year old girl is described. The diagnosis was established on the basis of an exudative pleural effusion with an amylase level above 4,000 IU/l. Management of effusion was by intercostal tube drainage and antibiotics.

Acute Disease↗
PubMed2001

Increase in calcitonin gene related peptide (CGRP) and decrease in mast cells in dihydroepiandrosterone (DHEA)-induced polycystic rat ovaries.

UNLABELLED: The polycystic ovary is reported to correspond with a high density in intraovarian nerve fibers and their sympathetic hyperresponsiveness. Peptidergic nerves may also be involved in this process. An interaction between nerve fibers and mast cells is assumed because of nerve growth-factor production by mast cells. Here we investigated CGRP-positive nerve fibers and mast cells in polycystic ovaries induced in immature rats with dihydroepiandrosterone (DHEA). The DHEA treated ovaries contained less corpora lutea than controls (mean +/- SEM: 4.3 +/- 0.6 versus 11.3 +/- 0.9, P > 0.001) and less intact antral follicles (4.7 +/- 0.7 versus 8.1 +/- 1.1; P < 0.05) according to the histometric approach. By immunolabelling more CGRP-positive nerve fibers were found in the DHEA treated ovaries than in controls (mean +/- SEM per one section: 23.2 +/- 5.8 fibers versus 10.3 +/- 0.9 and 171 +/- 44.7 varicosities versus 84 +/- 9.5). This was confirmed by dot blot analysis, showing a significant higher CGRP signal intensity per microgram homogenized ovaries of the DHEA treated group compared to the untreated (P < 0.05). Toluidine-blue-stained mast cells populated the medulla in both groups, yet had strikingly decreased in the DHEA treated ovaries (23.5 +/- 3.9 versus 89 +/- 5.6, P < 0.005). CONCLUSION: The increase in CGRP-positive nerve fibers and the decrease of toluidine-blue-stained mast cells points to an altered neuroimmune function in DHEA-induced polycystic rat ovaries.

Animals↗
PubMed2000

Seasonal changes in circulating testosterone and androstenedione concentration and their correlation with the anomalous reproductive pattern in the male indian sheath-tailed bat, Taphozous longimanus.

The relationship between reproductive organs, circulating testosterone, and androstenedione concentration in the male sheath-tailed bat, Taphozous longimanus, was studied. The masses of testis, accessory sex gland (prostate, ampullary), and epididymides showed three peaks, one each in October, January, and April. Monthly changes in testosterone also peaked during October, January, and April and closely coincided with the peak spermatogenesis. Serum androstenedione concentration peaked during November and January. Testosterone showed a strong correlation with masses of testis and accessory sex glands, while androstenedione showed strong correlation with the body mass. Different threshold levels of testosterone may be required to trigger spermatogenesis, secretory activity of accessory sex glands and mating in Taphozous longimanus and may be responsible for reproductive asynchrony in this species. Higher circulating concentrations of testosterone and androstenedione throughout the year in this species, as compared with other mammalian species, may be responsible for prolonged retention of sperm in the epididymides.

Androstenedione↗
PubMed2000

Seasonal adiposity and androstenedione production as a possible mechanism for asynchronous reproductive activity between males and females of vespertilionid bat, Scotophilus heathi.

Relationship between changes in the body weight and circulating androstenedione concentration was examined in order to find out their involvement in asynchronous gametic cycle of male and female S. heathi. Body weight of both male and female bats increased from September due to accumulation of white adipose tissue and reached to a peak in November. The body weight declined gradually due to consumption of adipose tissue during December and January reaching basal level in February. A significant correlation between body weight and serum androstenedione concentration was observed. Correlated with maximum body weight, peak androstenedione level was found during November in both male and female bats. Peak androstenedione level during November may be responsible for stimulating spermatogenesis in the male, but may suppress follicular growth and ovulation in the female, thus resulting in asynchronous gametic cycle of male and female S. heathi.

Adipose Tissue↗
PubMed1999

Accessory limbs associated with spina bifida - a second look.

An accessory limb associated with spina bifida was already reported by the authors. We had then described it as a result of a very early splitting of the limb bud arising from the paraxial mesoderm. We have subsequently seen three other such cases, which are described in this report as well as a review of five other cases in the literature. It is proposed that the growth of the accessory limb occurs from a mesodermal blastema that is a result of de-differentiation from Schwann cells.

Abnormalities, Multiple↗
PubMed1999

Possibility of inhibin as a regulator of androstenedione production by the ovary during the period of delayed ovulation in a vespertilionid bat, Scotophilus heathi.

The aim of the present study was to evaluate the role of inhibin in regulating androstenedione production by the ovary of Scotophilus heathi during the period of delayed ovulation. Inhibin alone increased the androstenedione synthesis in vitro by the ovary during all reproductive phases, but augmented the hCG induced androstenedione production only during November. The follicles produced significantly higher androstenedione as compared to the stromal or granulosa cell in response to both hCG and inhibin. However, inhibin augmented hCG stimulated androstenedione in the stromal cell only. Immunoreactivity of inhibin subtype alpha, betaA and betaB were mainly localized in the thecal and interstitial cell from September to November and then declined during the preovulatory period. However, in granulosa cells weak to moderate immunoreactivity of all inhibin subtype was observed during these phases. These results indicate the possible role of inhibin in regulating androstenedione synthesis by the ovary and thus. may be indirectly responsible for causing delayed ovulation in S. heathi.

Androstenedione↗
PubMed1998

Precursor lesions of Wilms' tumor in Indian children: a multiinstitutional study.

BACKGROUND: Studies regarding different ethnic populations of children with Wilms' tumor (WT) in the U. S. have shown differences between age and gender incidence and the type of its precursor lesions (nephrogenic rests). To the authors' knowledge there are few reports in the literature regarding nephrogenic rests in a large number of cases from other parts of the world. METHODS: In this study, histopathology sections from 127 WTs were pooled from the archives of 4 institutions in northern India and studied for the incidence of nephrogenic rests. Their incidence also was cross-correlated with patient age gender, and tumor morphology. RESULTS: Significantly, the complete absence of perilobar nephrogenic rests was observed in all cases. Intralobar rests were associated with 45.3% of WTs and were observed predominantly with a triphasic histologic pattern and a relatively lower incidence of anaplasia compared with reports in the Western literature (1.5% vs. 4.5%). A lower median age of 2.5 years with a peak in the first 2 years of life was consistent with reported studies in Asian children. The male gender preponderance was in contrast to the equal male to female ratio reported in Western cases. CONCLUSIONS: The type of nephrogenic rests present in Indian children was noted to be different from that in children reported in the Western literature. Differences also existed with regard to the age and gender incidence of children with WT and its morphologic pattern, possibly due to the different genetic nature of the tumor. However, this theory requires confirmation by large epidemiologic and genetic studies.

Age Distribution↗
PubMed1998

Changes in circulating insulin and corticosterone concentrations during different reproductive phases and their relationships to body weight and androstenedione concentration of male Scotophilus heathi.

The aim of the present study was to determine the serum levels of insulin and corticosterone during different reproductive stages in a natural population of the male bat, Scotophilus heathi and their relationship to body weight and androstenedione level. Changes in body weight were marked by weight gain before winter dormancy and weight loss during winter dormancy. Circulating insulin level varied significantly over the season and correlated positively with changes in body weight and androstenedione level. Circulating corticosterone level also varied significantly over the season but correlated negatively with changes in body weight and androstenedione level. High corticosterone level during August coincided with a period of increased feeding activity in this species. The results suggest that insulin may act as an anabolic agent to promote fat deposition and corticosterone exerts a predominantly fat-mobilizing influence. A high insulin level prior to winter dormancy may be an important factor responsible for inducing high androstenedione concentration shown in Scotophilus heathi.

Adipose Tissue↗
PubMed1998

Congenital H-type urethroanal fistula.

A case of congenital urethroanal fistula with a normal anterior urethra in a male child is reported. The fistula was demonstrated between the prostatic urethra and anorectum. This anomaly is usually associated with an atretic anterior urethra and has been variously described as a variant of a urethral duplication by some authors, and of an anorectal malformation (ARM) by others. We conclude that its rightful classification is as a variant of ARM in which the fistula is a result of persistence of the cloacal duct and corresponds to the anorecto-vestibular fistula with a normal anus (perineal canal) in a female.

Humans↗
PubMed1998

Posterior urethral valves after infancy-urodynamic consequences.

This study describes a subset of patients with posterior urethral valves (PUV) who presented late in childhood. The objective was to identify factors that lead to back-pressure effects on the upper tracts, which persist in spite of adequate valve ablation in some patients, and seek factors that may preserve the upper tracts despite untreated obstruction in other patients. Six children with PUV diagnosed after infancy were evaluated. The pre-operative work-up included renal biochemistry, ultrasonography, voiding cystourethrography, and uroflowmetry. Detailed urodynamic studies, including uroflowmetry and slow-fill cystometry, were performed in all cases 6 months after surgery. Adequacy of valve fulguration was confirmed by urethroscopy. Three of the six patients had normal upper tracts; in these, there was marked improvement in peak urine flow rates after fulguration and bladder pressures were normal. The other three patients had bilateral hydroureteronephrosis, and two had chronic renal failure. This group had markedly decreased functional bladder capacity with loss of compliance at low bladder volumes and significant residual urine volumes in spite of adequate valve fulguration, suggesting myogenic detrusor failure. We conclude that in patients with PUV presenting beyond the age of 5 years, upper-tract deterioration may accompany high storage pressures in the bladder. In some boys with long-standing obstruction the upper tracts may escape damage; in our series this was associated with normal bladder dynamics and appeared unrelated to the severity or duration of outflow obstruction.

Child↗
PubMed1998

Perinephric abscess (presenting as abdominal pain) due to Listeria monocytogenes.

A 5-year-old malnourished child was admitted with a 1-week history of paroxysmal abdominal pain. Evaluation finally revealed a left-sided perinephric abscess caused by Listeria monocytogenes. The child was successfully treated by drainage of the abscess and antibiotic therapy. Renal abscess should be kept in mind in the differential diagnosis of abdominal pain, and Listeria, an unusual pathogen, should be considered as a possible aetiology.

Abdominal Pain↗
PubMed1998

Leopard syndrome: a tropical rarity.

This is a case report of a classical presentation of the Leopard syndrome from the Indian subcontinent. The male patient had progressively increasing generalised multiple lentiginosis, ocular hypertelorism, pulmonary stenosis, short stature, cryptorchidism, and pectus excavatum. The case is documented for its rarity in this part of the world and typical clinical presentation.

Abnormalities, Multiple↗