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U Rai

Publications and source records attributed to U Rai.

18 recordsLinked to original sources
PubMed2005

Mechanism of androgen-induced thymic atrophy in the wall lizard, Hemidactylus flaviviridis: an in vitro study.

The present in vitro study demonstrates the effect of androgen on thymocyte apoptosis leading to thymic atrophy in the wall lizard, Hemidactylus flaviviridis. Thymocytes collected from castrated lizards were incubated with varying concentrations of dihydrotestosterone (DHT) to observe its effect on proliferation and apoptosis. DHT treatment reduced the tritiated thymidine incorporation in thymocytes, suggesting that androgen directly inhibits thymocyte proliferation. It also caused apoptosis of thymocytes effectively at 10(-7)M. However, the increased apoptotic action of DHT was indirectly mediated through thymic epithelial cell-rich stromal cell components (TEC). This observation was reaffirmed by in vitro incubation of thymocytes with DHT-pretreated TEC-conditioned medium. However, the DHT-induced TEC-secreted apoptotic factors could induce thymocyte DNA fragmentation only when DHT was added to the conditioned medium. It implies that DHT priming of thymocytes is required for the apoptotic effect of DHT-induced TEC-secreted factor. DHT-induced thymocyte apoptosis was found to be caspase-dependent since it activated the initiator (caspase-9) and effector caspases (caspases-3 and -7) as well as cleaved the enzyme substrate poly(ADP-ribose) polymerase (PARP). Further, the apoptotic effect of DHT was routed through its classical receptors, as non-steroidal antiandrogen flutamide blocked the DHT-induced thymocyte apoptosis. The inhibition of apoptosis by transcription/translation inhibitors further substantiates the genomic pathway of DHT action. It can be concluded that DHT, in addition to inhibiting thymocyte proliferation directly, accelerates caspase-dependent apoptotic process in thymocytes indirectly through TEC via a genomic pathway. Nevertheless, the priming of thymocytes with DHT is required for the apoptotic effect of TEC-secreted factor.

Androgen Antagonists↗
PubMed2004

Glucocorticoid-induced thymocyte apoptosis in wall lizard Hemidactylus flaviviridis.

The aim of the present study is to demonstrate the phenomenon and mechanism of GC-induced cell death of thymocytes in wall lizard Hemidactylus flaviviridis. Lizard thymocytes were treated in vitro with different concentration of corticosterone (CS) for varying durations and the genomic DNA was analyzed both by agarose gel electrophoresis and flow cytometry. Corticosterone induced DNA fragmentation in a dose-dependent manner, as the DNA laddering was more prominent at 10(-14) M than at lower concentrations. However, CS could activate the programmed cell death of thymocytes only when incubated for 48 h and not at 3, 6, 12, or 24 h. Similar results were obtained following the flow cytometric analysis. The highest apoptotic cell death was noted at 10(-14) M concentration. CS-induced programmed cell death was decreased dramatically when the thymocytes were preincubated with RU 486 (10(-9) ng /ml) for 24 h, suggesting the classical receptor-mediated genomic pathway of glucocorticoid action in inducing apoptosis of thymocytes in wall lizard H. flaviviridis.

Animals↗
PubMed2004

In vitro effect of FSH and testosterone on Sertoli cell nursing function in wall lizard Hemidactylus flaviviridis (Rüppell).

The present in vitro Sertoli cell-enriched culture study was aimed to understand the precise role of FSH and testosterone either alone or in combination in regulation of Sertoli cell nursing function such as lactate production, which in turn is utilized by the germ cells as an energy substrate. The stimulatory effect of FSH on lactate production by Sertoli cell-enriched culture was significantly enhanced when FSH and dihydrotestosterone were supplemented in the medium either simultaneously or DHT was added 12 h later to FSH (0 h FSH+12 h DHT). On the contrary, DHT alone or added 12 h prior to FSH (0 h DHT+12 h FSH) in the incubation medium, significantly reduced the lactate secretion by Sertoli cells as compared to control or FSH alone/FSH+DHT simultaneously/0 h FSH+12 h DHT, respectively. This provides the conclusive evidence that androgen has additive effect on nursing function of Sertoli cell-enriched clusters only when they are in an activated state in response to gonadotropin.

Animals↗
PubMed2001

In vitro effect of temperature on phagocytic and cytotoxic activities of splenic phagocytes of the wall lizard, Hemidactylus flaviviridis.

The in vitro effect of temperature on phagocytosis, nitric oxide production and interleukin-1 (IL-1) secretion by splenic phagocytes isolated from the wall lizard (Hemidactylus flaviviridis) demonstrated that changes in temperature altered non-specific defenses. The LPS-induced percentage phagocytosis and phagocytic index were recorded maximum at 25 degrees C. The phagocytic activity declined considerably when the phagocytes were incubated at low (7 and 15 degrees C) or high (37 degrees C) temperatures. The presence of bacterial lipopolysaccharide (LPS) in the incubation medium could considerably enhance the phagocytic activity of splenic phagocytes. A similar temperature-related effect was also observed on LPS-induced cytotoxic activity of phagocytes. LPS could stimulate the nitrite release indicating nitric oxide production only at 25 degrees C. Likewise, the proliferative responses of immature rat's thymocytes to LPS-induced phagocyte-conditioned medium suggest that IL-1 secretion was enhanced when phagocytes were cultured at 25 degrees C. This suggests that 25 degrees C is the optimal temperature for phagocyte functions in H. flaviviridis. The decrease or increase in temperature other than at 25 degrees C dramatically suppressed the phagocyte activities.

Animals↗
PubMed2001

Thymic structural changes in relation to seasonal cycle and testosterone administration in wall lizard Hemidactylus flaviviridis (Ruppell).

Light microscopic and ultrastructural studies of thymus in wall lizard showed remarkable season dependent structural changes. In winter, the thymus was involuted and its cortico-medullary differentiation was not distinct. Thymocytes were sparsely distributed. The epithelial cells exhibited atrophic features such as an appreciable decrease in the nuclear-cytoplasmic ratio and accordingly reduction in cell organelles. The reconstruction of thymus commenced during spring and it became fully developed with marked delineation of cortico-medullary regions during summer. The thymus was then densely populated with thymocytes and epithelial cells showed voluminous cytoplasm having numerous cell organelles. The thymus regression started again by the beginning of autumn. The results suggest that the thymic development in wall lizard have inverse relationship with the androgen level, as the testicular steroidogenic activity was seen maximum during winter and least in summer. This assumption gets support by castration and testosterone replacement experiments. Castration of lizards during winter resulted in profound development of thymus with an appreciable increase in thymocytes mainly in the cortex region . The cortex became delineated from the medulla. Following testosterone treatment, the thymus underwent regression and was comparable to testis-intact lizard's thymus during winter season. After withdrawal of testosterone treatment, the thymus exhibited dense lymphoid and thymocyte population with a demarcation of cortico-medullary regions and sub-cortical region was regenerated.

Androgens↗
PubMed2000

Epididymal protein secretion and its androgenic control in wall lizards Hemidactylus flaviviridis (Ruppell).

The total protein level in different segments of epididymis of normal lizard exhibited noticeable increase from early February to late March of a same reproductive phase. Comparison among the protein level of different epididymal segments showed insignificant variation from anterior to posterior part in early February but in late March, the protein level in posterior segment was appreciably higher than in anterior and middle segments. Further, testosterone-induced epididymal protein did not exhibit any significant quantitative variation among different regions. The electrophoretic pattern of luminal fluid from different epididymal regions of normal lizard showed 28 protein bands without any marked regional difference. However, only 16 protein bands could be demonstrated in the epididymal fluid of any region. Unlike molecular size, isoelectric focussing of testosterone induced epididymal proteins revealed that three regions of epididymis differ in their nature of protein. The number of proteins having alkaline pH range in anterior and middle regions were 4 and 3, respectively which increased upto 6 in posterior region.

Androgens↗
PubMed1999

Sexual dimorphism in phagocytic activity of wall lizard's splenic macrophages and its control by sex steroids.

The splenic macrophages of wall lizards exhibited marked sex-related difference in their phagocytic activity. The percentage phagocytosis and phagocytic index in females was considerably higher than that of males. Gonadectomy resulted in significant increase in percentage phagocytosis and phagocytic index in both male as well as female lizards, suggesting that gonadal hormones inhibit macrophage phagocytosis. This was further confirmed by dose and time-related in vivo and in vitro experiments in which DHT suppressed phagocytosis which increased with dose or duration of treatment, while E(2) either suppressed or had no effect on phagocytosis, depending on dose and duration of treatment. Exposure of macrophages to steroid receptor antagonists, cyproterone acetate (CPA), or tamoxifen citrate (Tam) prior to treatment with their respective sex steroids markedly reduced the DHT- or E(2)-modulated suppression of macrophage phagocytosis. It is concluded that the sex steroids modulate splenic macrophage phagocytosis via receptor-mediated systems.

Animals↗
PubMed1998

Sex steroid hormones modulate the activation of murine peritoneal macrophages: receptor mediated modulation.

The comparative dose and time-dependent effects of male and female sex steroid hormones on nitrite release by murine peritoneal macrophages (M phi) stimulated by LPS were studied. M phi from gonadectomized mice released larger amounts of nitrite on LPS stimulation than controls; although nitrite release was significantly greater in castrated males than in ovariectomized females, suggesting that sex hormone deprivation results in an increase in nitrite release. This was further confirmed by in vitro treatment of M phi with estradiol (E2), testosterone (T) and progesterone (P) at different doses and duration prior to, and during, stimulation of nitrite production by LPS. E2 (except at 10(-2) ng/ml), T and P significantly (P < 0.05) suppressed the nitrite release in a dose-dependent manner. Nitrite release from M phi increased with decreasing exposure time to E2, T and P. Preincubation of M phi with sex hormones prior to LPS treatment also reduced nitrite production. Sex steroid receptor antagonists tamoxifen citrate, cyproterone acetate/flutamide and RU486 markedly reduced the inhibitory effect of E2, T and P, respectively, suggesting that sex hormones modulate M phi nitrite release via a receptor-mediated system.

Animals↗
PubMed1998

Activation of the JAK-STAT pathway by reactive oxygen species.

Reactive oxygen species (ROS) play an important role in the pathogenesis of many human diseases, including the acute respiratory distress syndrome, Parkinson's disease, pulmonary fibrosis, and Alzheimer's disease. In mammalian cells, several genes known to be induced during the immediate early response to growth factors, including the protooncogenes c-fos and c-myc, have also been shown to be induced by ROS. We show that members of the STAT family of transcription factors, including STAT1 and STAT3, are activated in fibroblasts and A-431 carcinoma cells in response to H2O2. This activation occurs within 5 min, can be inhibited by antioxidants, and does not require protein synthesis. STAT activation in these cell lines is oxidant specific and does not occur in response to superoxide- or nitric oxide-generating stimuli. Buthionine sulfoximine, which depletes intracellular glutathione, also activates the STAT pathway. Moreover, H2O2 stimulates the activity of the known STAT kinases JAK2 and TYK2. Activation of STATs by platelet-derived growth factor (PDGF) is significantly inhibited by N-acetyl-L-cysteine and diphenylene iodonium, indicating that ROS production contributes to STAT activation in response to PDGF. These findings indicate that the JAK-STAT pathway responds to intracellular ROS and that PDGF uses ROS as a second messenger to regulate STAT activation.

3T3 Cells↗
PubMed1998

Screening for chlamydial infections in women with pelvic inflammatory diseases.

One hundred female patients clinically diagnosed as pelvic inflammatory disease (PID) were studied for the presence of chlamydial infection by cytology and antigen detection. Cervical smears stained by Giemsa revealed inclusion bodies, only in 3 percent of cases. While using Immunocomb Enzyme Immunoassay (EIA) test, antigen was detected in 13% of cases, thereby showing that antigen detection is a better method than cell cytology. A significant correlation with the low socioeconomic status and younger age group was seen in patients showing presence of Chlamydia trachomatis antigen.

Adolescent↗
PubMed1995

Effects of cyproterone acetate on FSH and testosterone influenced spermatogenesis, steroidogenesis and epididymis in the Indian wall lizard, Hemidactylus flaviviridis (Ruppell).

The effects of FSH, testosterone and either cyproterone acetate (CPA) alone or in combination with FSH or testosterone on testis and epididymis in male lizards were studied histologically and histochemically during recrudescent phase to find out whether the onset of spermatogenesis is androgen dependent or FSH dependent. The testes of control lizards consisted of mainly spermatogonia, a few primary spermatocytes and secondary spermatocytes rarely. The interstitial or Leydig cells were atrophied. FSH treatment induced spermatogenic activity substantially as indicated by increase in number of primary and secondary spermatocytes and transformation of secondary spermatocytes into spermatids and into spermatozoa in a few cases. Besides, steroidogenic activity was also remarkably stimulated as evidences by considerable depletion of sudanophilic lipid and an increase in Delta5-3beta-hydroxysteroid dehydrogenase enzyme activity in Leydig cells. However, testosterone treatment resulted in the inhibition of spermatogenesis. A significant inhibition of spermatogenesis was noted in lizards treated either with CPA alone or in combination with FSH. The inhibitory effect of CPA on spermatogenesis was increased when it was given in combination with testosterone. The results indicate that onset of spermatogenic activity is dependent on FSH (or FSH-like protein), but not on the androgen. The ductus epididymidis in control lizards was regressed with low cuboidal epithelium. The lumen of the tubules was totally devoid of secretory material and spermatozoa. FSH treatment induced a marked hypertrophy in epididymidis. The lumen became filled with secretory material mixed with spermatozoa. The hypertrophy in epididymidis was also recorded after the treatment with testosterone, but the degree of induction was not to that extent as noted in FSH treated ones. However, CPA injected either with FSH or with testosterone resulted in the profound atrophy in epididymidis.

Animals↗
PubMed1991

Testis and epididymis of the Indian wall lizard (Hemidactylus flaviviridis): effects of flutamide on FSH and testosterone influenced spermatogenesis, Leydig cell, and epididymis.

To determine the separate spermatogenic actions of FSH and testosterone, adult male lizards Hemidactylus flaviviridis with recrudescent testes were administered the non-steroidal antiandrogen flutamide either alone or in combination with FSH or testosterone, and the histology and histochemistry of the testes and ductus epididymides were studied. Flutamide-treated animals displayed a marked hypertrophy of Leydig cells. A few spermatids were also seen in testis of more than half the animals treated with flutamide. Flutamide also produced a significant increase of primary spermatocytes; no spermatids were observed in controls. A significant inhibition of spermatogenesis was noted in lizards treated either with testosterone alone or in combination with flutamide. Ovine FSH treatment caused a significant stimulation of spermatogenesis, as indicated by the increase of primary and secondary spermatocytes and the transformation of secondary spermatocytes into spermatids or, in a few cases, into spermatozoa. A considerable depletion of sudanophilic lipid and moderate delta 5-3 beta-hydroxysteroid dehydrogenase activity was noted in the Leydig cells of FSH-treated animals indicating enhanced steroidogenesis. Similar results were obtained when lizards were treated with flutamide + FSH. The effects of simultaneous treatment of flutamide with FSH or testosterone on ductus epididymidis revealed that flutamide markedly inhibited the epithelial cell height and lumen diameter with a loss of luminal content when compared to FSH or testosterone-treated lizards.

Animals↗
PubMed1989

Breast feeding practices and maternal employment.

Little information exists about the relationship between maternal employment and breast feeding practices and knowledge about lactation. The study was conducted on 318 employed and 299 non-employed women prospectively. Lactational practices were significantly influenced by employment status, with 81.9% non-employed vs. only 49.7% employed going in for exclusive breast feeds in the first 3 months (p less than .001). Correspondingly, 46.8% employed women started combined breast and bottle feeds from birth (p less than .001). Within the employed group, parity and social class did not significantly alter the infant feeding practices. Employed women were better informed about feeding and weaning as compared to their non-employed counterparts (36.8% vs. 18.4% p less than .001). Women from higher social class also tended to be more aware (59.8% vs. 7.2%: p less than .001). Multiparas had an edge over primiparas with respect to knowledge about lactation (36.1% vs. 20.1% p less than .01).

Breast Feeding↗
PubMed1986

Effects of cyproterone acetate and flutamide on the testis and epididymis of the Indian wall lizard, Hemidactylus flaviviridis (Ruppell).

Intramuscular injections of 0.2 mg cyproterone acetate (CA) or flutamide every other day for 6 weeks resulted in the inhibition of spermatogenesis. While CA treatment reduced the weight of the testis significantly, flutamide did not. Inhibition of steroidogenesis, indicated by an accumulation of sudanophilic lipid and a decrease in delta 5-3 beta-hydroxysteroid dehydrogenase and glucose-6-phosphate dehydrogenase activity, was evident in the Leydig cells of CA-treated testis. Flutamide, on the other hand, had no effect on the activity of Leydig cells. A marked decline in epididymal weight, as well as reduction in epithelial cell height, was caused by both CA and flutamide. The epithelial cells of epididymes of treated lizards exhibited an accumulation of sudanophilic lipid material in their cytoplasm. However, sudanophilic secretions present in the lumina of epididymal tubules were greatly reduced. This indicates either lack of synthesis of lipid or decrease in its turn over. Our results are in agreement with those obtained in mammalian species after CA or flutamide treatment where a decrease in fertility is suggested.

Anilides↗
PubMedDate not supplied

Epididymal influence on acquisition of sperm motility in the gekkonid lizard Hemidactylus flaviviridis.

Total sperm count and percent sperm motility were noted in different parts of the epididymis, and the effect of anterior, middle, and posterior epididymal fluid on the induction of motility of nonmotile testicular spermatozoa was observed. The results were used to compare the influence of different parts of epididymis of Hemidactylus flaviviridis on the acquisition of sperm motility, which is a sign of sperm maturation. Spermatozoa collected from different regions of the ductus epididymidis showed considerable difference in their motility as well as total count with an increase from anterior to posterior region. The epididymal fluids from different regions induced the motility of testicular spermatozoa and the induction accelerated with increasing fluid volume and incubation period. Epididymal fluid at higher volumes induced the motility of nonmotile testicular spermatozoa significantly even at short-term incubation. Among different epididymal regions, fluid from posterior was more potent in influencing the motility than the fluids of middle and anterior. Motility pattern of spermatozoa varied from zig-zag, circular, and erratic in anterior to wavy in posterior region of epididymis. However, the mean sperm velocity did not show any regional variation.

Animals↗