PubMed Health⌕ Search

Biomedical subjects

K Bhattacharya

Publications and source records attributed to K Bhattacharya.

18 recordsLinked to original sources
PubMed2026

Reduced Length of ADT and ARTA With XRT in High-Risk Prostate Cancer (RELAX): A Randomised Controlled Trial.

AIM: To assess the efficacy of a short, intensified regimen of androgen deprivation therapy (ADT) and androgen receptor-targeted agent (ARTA) with curative-intent external beam radiotherapy (XRT) for high-risk prostate cancer (HRPCa) staged with prostate specific membrane antigen (PSMA) imaging. MATERIALS AND METHODS: The RELAX (Reduced Length of ADT and ARTA with XRT in high-risk prostate cancer) trial is a multicentre, phase II randomised non-inferiority trial comparing 9 months of ADT and 6 months of ARTA against the standard 24-month ADT, with definitive dose-escalated hypofractionated pelvic radiotherapy for PSMA-staged non-metastatic HRPCa. The primary endpoint is 5-year disease-free survival (DFS), defined from randomisation to first biochemical or clinico-radiological recurrence or any-cause death. Secondary endpoints include biochemical failure-free survival, metastasis-free survival, overall survival, testosterone recovery, treatment-related adverse effects, and patient-reported outcomes. Participants are monitored with serial serum PSA and testosterone levels, CTCAE and PRO-CTCAE assessments, and PSMA-PETCT at recurrence. The non-inferiority margin is set at 10% absolute difference from an expected 5-year DFS of 85% in the standard arm, with intention-to-treat analysis. The trial is ethics board approved and funded by institutional intramural grant, and registered on clinicaltrials.gov (NCT06818682). RESULTS: The planned accrual of 206 participants commenced in February 2025, with nearly a third of enrolment completed till date. CONCLUSION: The RELAX trial incorporates contemporary standards of PSMA-based staging, dose-escalated hypofractionated radiotherapy, and ARTA for HRPCa. The results are expected to inform the efficacy of a shorter, intensified androgen suppression strategy against the prevailing standard of long-term ADT for these patients.

Humans↗
PubMed1992

Quinalphos-induced suppression of spermatogenesis, plasma gonadotrophins, testicular testosterone production, and secretion in adult rats.

Quinalphos (O,O-diethyl-O-[quinoxalinyl-(2)-thionophosphate]) is a well-known organophosphorus insecticide used extensively in agriculture that adversely interferes with the activity of testicular steroidogenic enzymes in rats. To investigate its effects on spermatogenesis, the other function of testes, quantitative evaluation of different varieties of germ cells at stage VII of the seminiferous epithelium cycle, namely, type A spermatogonia (ASg), preleptotene spermatocytes (pLSc), midpachytene spermatcytes (mPSc), and step 7 spermatids (7Sd), along with the radioimmunoassay of plasma FSH, LH, testosterone, and testicular testosterone, were performed in Wistar rats following treatment with quinalphos (250 micrograms/kg, ip) for approximately one (13 days) and two cycles (26 days) of the seminiferous epithilium. Massive degeneration of all varieties of germ cells at stage VII, remarkable reduction in the sperm count, and significant reductions in plasma concentrations of FSH and testosterone, along with testicular testosterone, were observed after quinalphos treatment. Significant reduction in the plasma concentration of LH was observed only after treatment for two cycles. Administration of human chorionic gonadotrophin for 26 days in rats injected with quinalphos partially prevented the degeneration of germ cells and increased testosterone production. It is suggested that quinalphos may have a suppressive influence on gonadotrophin release but its direct detrimental action at the level of the testes may also be responsible for the observed changes in spermatogenesis and in testicular testosterone production in rats.

Animals↗
PubMed1990

Search for chromosomal variations among gas-exposed persons in Bhopal.

A chromosomal survey using standard lymphocyte cultures employing different media and G-banding techniques was initiated in 1984. This study became particularly important following the tragic gaseous exposure of the population in Bhopal at midnight on 2 December 1984. We have been able to formulate a chromosomal profile for each person whom we have studied; during 1986-1988, 154 persons were examined twice. Among seemingly normal individuals, as many as 20% might possess some chromosomal abnormality; of these, 50% may develop, at a later date, some kind of pathological complication (such as tumours, recurrent abortion or transmission of defects to their offspring). The people exposed to methyl isocyanate have repeatedly shown Robertsonian translocations, mostly in acrocentric chromosomes 13 and 21. Other types of translocations have been studied among all exposed (53) and normal (101) persons; the involvement of chromosomes 5, 9, 11, 14 and 16 is statistically significant (P = less than 0.001). One of the major clinical symptoms is dyspnoea; we have estimated that almost all seriously dyspnoeic patients have developed at least two categories of chromosomal aberrations, one of which is Robertsonian translocation, in at least 10% metaphases. Our chromosomal survey will be of significance because we are able to identify people with chromosomal aberrations that might be correlated with future pathological consequences of the accident. The "chromosomal load" that can be sustained with an apparently normal phenotype can also be measured.

Accidents, Occupational↗
PubMed1989

Bacteriology of pyodermas and antibiograms of pathogens.

One hundred and seventy six cases of various clinical types of pyodermas were investigated to find the causative organism of the disease. Folliculitis formed the largest clinical group followed by infectious eczematoid dermatitis, secondary infection, furuncles, impetigo, ecthyma and carbuncle in descending order of frequency. A total of 189 micro-organisms were isolated from the specimens examined. A single infecting organism was isolated from 74.43% and more than one type of organism from 16.48% of cases. Coagulase positive staphylococcus (73.02%) was the predominant species followed by beta-haemolytic streptococcus (26.98%). Coagulase positive staphylococcus was isolated from 109 (61.93%), beta-haemolytic streptococcus from 22 (12.5%) and both these organisms from 29 (16.48%) cases. The antibiotic resistance pattern showed maximum resistance to penicillin followed by ampicillin. None of the strain was found to be resistant to kanamycin. Low percentage of strains were found to be resistant to streptomycin, oxytetracycline, trimethoprim, cloxacillin, erythromycin, chloramphenicol, cephalexin, gentamycin and neomycin.

Ampicillin↗
PubMed1989

Lupus nephritis--light, electron and immunofluorescent microscopy (a clinicopathological study).

Kidney biopsy specimens from nine patients of systemic lupus erythematosus were studied for the purpose of correlating the findings of light and electron microscopy and immunofluorescent studies with the kidney functions and the presence of proteinuria. Morphologically, three were mesangiocapillary glomerulonephritis, three mesangioproliferative glomerulonephritis and one membranous nephropathy. Subendothelial deposits were observed in eight cases, subepithelial deposits in seven cases and mesangial deposits in eight cases. Four cases with massive subendothelial deposits had massive proteinuria and decrease in renal functions. Most of the patients with mild subendothelial deposits were considered to be useful in assessing the prognosis and severity of lupus nephropathy, in addition to the morphologic types of lesions, as mesangial pattern had shown insignificant proteinuria. Study of semithin sections by light microscopy could demonstrate the deposits which were observed on electron microscopy and immuno-fluorescent microscopy.

Adult↗
PubMed1988

Effect of aldrin on spermatogenesis, plasma gonadotrophins and testosterone, and testicular testosterone in the rat.

Quantitative evaluation of the different varieties of germ cells at stage VII of the seminiferous epithelium cycle, namely type-A spermatogonia (ASg), preleptotene spermatocytes (pLSc), mid-pachytene spermatocytes (mPSc) and step 7 spermatids (7Sd), along with radioimmunoassay of plasma gonadotrophins (FSH and LH), testosterone and testicular testosterone were performed in Wistar rats following treatment with aldrin (polycyclic chlorinated hydrocarbon insecticide) for approximately one (13 days) or two cycles (26 days) of the seminiferous epithelium. Extensive degeneration of all varieties of germ cells at stage VII, reduction in the sperm count and significant reductions in plasma concentrations of LH and testosterone were observed following aldrin treatment. The reduction in plasma concentrations of FSH was statistically significant only after treatment for two cycles. The inhibitory effect of aldrin on plasma gonadotrophins, testosterone levels, testicular testosterone content and numbers of 7Sd and ASg was maximum after treatment for two cycles. Administration of human chorionic gonadotrophin along with aldrin treatment for two cycles partially prevented the degeneration of germ cells and enhanced testosterone production. The results indicate that aldrin may have a direct inhibitory influence on gonadotrophin release, but the possibility of a direct action of the insecticide at the level of the testes is also discussed.

Aldrin↗
PubMed1986

Flowers of Hibiscus rosa-sinensis, a potential source of contragestative agent. III: Interceptive effect of benzene extract in mouse.

In mouse, oral administration of the benzene extract of Hibiscus rosa-sinensis flowers at a dose level of 1 gm/kg body weight/day from day 5-8 of gestation led to termination of pregnancy in about 92% of the animals. The effect was associated with a significant fall in peripheral level of progesterone and increase in uterine acid phosphatase activity, as measured on day 10. The ovary exhibited signs of luteolysis, and the corpus luteal delta 5-3 beta -hydroxysteroid dehydrogenase activity decreased markedly. The interceptive effect of the extract was prevented completely by exogenous progesterone (1 mg/mouse/day) or chorionic gonadotropin (1 I.U./mouse/day) and partially (62.5%) by exogenous prolactin (500 micrograms/mouse/day). In unilaterally pregnant mouse having trauma-induced deciduomata in the sterile horn, the extract caused resorption of the fetuses, and regression of the deciduomata accompanied by reduction in weight of the ovaries. Luteolysis, may be due to interference with the luteotropic influence, and a consequent fall in plasma level of progesterone have been suggested as the plausible cause of termination of pregnancy.

Abortifacient Agents↗
PubMed1985

Flowers of Hibiscus rosa-sinensis, a potential source of contragestative agent: II. Possible mode of action with reference to anti-implantation effect of the benzene extract.

Benzene extractives of Hibiscus rosa-sinensis flowers, administered during day 1-4 of gestation, exerted anti-implantation effect without affecting the tubal transport of zygote. On day 4, normal number of blastocyst was present in the uterus but they did not implant. However, as studied by pontamine blue reaction, it was evident that hyper-permeability of the endometrial capillaries which is the earliest known response of a receptive endometrium to any kind of deciduogenic stimulus was inhibited by the extract. The magnitude of decidualization, as assessed by weight of the traumatized uterine horn and supported by the histological pictures of the uteri was significantly lower in comparison to that of the controls. Ovarian structure exhibited signs of luteolysis. Inadequate progestational development of the endometrium due to interference with the conditioning of the uterus with progesterone during prenidatory phase of pregnancy has been suggested as the plausible cause of the extract-induced implantation failure.

Animals↗
PubMed1976

Chromosome damage induced by semicarbazide in spermatocytes of a grasshopper.

Semicarbazide hydrochloride (0.1 M in glass-distilled water), on injection, showed mutagenic action on the spermatocyte chromosomes of the grasshopper, Spathosternum prasiniferum. Aberrations such as chromatid and chromosome breaks, translocations, fragments and bridges were encountered. The sex chromosome and the long autosomes were affected. Semicarbazide, perhaps, reacts with DNA and the chromosome in a way similar to that of hydroxylamine and hydrazines.

Animals↗
PubMed1976

Studies on the effect of phytagglutinins on some members of Enterobacteriaceae.

Extracts of twenty seeds were tested against twenty six organisms belonging to Klebsiella, Proteus, Salmonella, Shigella and Cholera species. Extracts of eleven seeds showed agglutinating activity against twenty four various organism. S. typhi and Kl. aerogenes did not react against any lectin. On the basis of the results it was possible to differentiate various Shigella and Salmonella organisms by various seed extracts. Different isolates of cholera organisms of same serotype and phage type showed different reaction suggesting that probably these organisms possess different antigenic characters. Thus phytagglutinins may be of some help in the identification and subtyping of these organisms.

Enterobacteriaceae↗