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Biomedical subjects

S K Roy

Publications and source records attributed to S K Roy.

At least 19 recordsLinked to original sources
PubMed1992

Cell-type-specific localization of transforming growth factor-beta 2 and transforming growth factor-beta 1 in the hamster ovary: differential regulation by follicle-stimulating hormone and luteinizing hormone.

Cell-type-specific localization and gonadotropin regulation of transforming growth factor-beta 1 (TGF-beta 1) and transforming growth factor-beta 2 (TGF-beta 2) in the hamster ovary were evaluated immunohistochemically under three conditions: (1) during the estrous cycle (Day 1 = estrus; Day 4 = proestrus); (2) after the blockade of periovulatory gonadotropin surges by phenobarbital, and (3) after FSH and/or LH treatment of long-term hypophysectomized hamsters. Ovarian TGF-beta 1 activity was primarily localized in theca and interstitial cells. The activity increased moderately but significantly after the preovulatory LH surge and reached a peak at 0900 h, Day 2 h; oocytes showed considerable activity. TGF-beta 1 immunoreactivity subsequently fell to low levels in theca-interstitial cells through 0900 h, Day 4. Significant TGF-beta 2 immunoreactivity appeared after the surge, mainly in the granulosa cells of both preantral and antral follicles; a few interstitial cells surrounding preantral follicles showed discrete staining. TGF-beta 2 immunoreactivity in granulosa cells and in interstitial cells next to preantral follicles reached a peak at 0900 h, Day 1, and persisted up to 0900 h, Day 2; oocytes showed no staining. Phenobarbital treatment blocked the appearance of TGF-beta 1 and TGF-beta 2 immunoreactivities at 1600 h, Day 4; however, a rebound in immunoreactivities was observed with the onset of the surge after a 1-day delay. Replacement of LH to long-term hypophysectomized hamsters resulted in a marked increase in TGF-beta 1 immunoreactivity in the interstitial cells, but FSH, although it induced follicular development, did not influence ovarian TGF-beta 1 activity. Treatment with FSH, however, induced a massive increase in TGF-beta 2 immunoreactivity in the granulosa cells of newly developed antral and preantral follicles but not in the interstitial cells; LH, on the other hand, had no significant effect on TGF-beta 2 activity. Treatment with FSH and LH combined resulted in a dramatic increase in TGF-beta 2 immunoreactivity in granulosa and interstitial cells and in TGF-beta 1 in theca and interstitial cells comparable to their peak activity in intact animals. Western analyses substantiated the presence of TGF-beta 1 and TGF-beta 2 in the hamster ovary and the specificity of immunolocalization. These studies, therefore, provide critical evidence that TGF-beta 1 and TGF-beta 2 in the hamster ovary are expressed in specific cell types and that their expression is differentially regulated by LH and FSH, respectively.

Animals↗
PubMed1992

Impact of zinc supplementation on intestinal permeability in Bangladeshi children with acute diarrhoea and persistent diarrhoea syndrome.

Zinc has been shown to enhance intestinal mucosal repair in patients suffering from acrodermatitis enteropathica; but the impact on mucosal integrity during acute (AD) or persistent (PD) diarrhoea is unknown. One hundred eleven children with AD and 190 with PD aged between 3 and 24 months received, randomly and blind to the investigators, either an elemental zinc supplement of 5 mg/kg body wt/day or placebo in multivitamin syrup for 2 weeks while intestinal permeability and, biochemical and anthropometric markers were serially monitored. The permeability test was administered as an oral dose of 5 g lactulose/l g mannitol in a 20-ml solution followed by a 5-h urine collection. The ratio of the urinary probe sugars was correlated to clinical, biochemical, and microbiological parameters. At presentation, lactulose excretion was increased and mannitol excretion decreased in both AD and PD as compared with age-matched asymptomatic children. The lactulose/mannitol ratio (L/M) was higher in subjects with mucosal invasive pathogens (rotavirus and enteropathogenic Escherichia coli) compared with children excreting Vibrio cholera and enterotoxigenic E. coli. Two-week zinc supplementation significantly reduced lactulose excretion in both AD and PD, whereas the change in mannitol excretion and L/M was similar between study groups in both studies. Changes in lactulose excretion were significantly influenced by zinc supplementation in children with E. coli, Shigella sp., and Campylobacter jejuni stool isolates. The greatest reduction in total lactulose excretion was seen in supplemented children who on presentation were lighter (wt/age less than 80%), thinner (wt/ht less than 85%), and undernourished [middle upper arm circumference (MUAC) less than 12.5 cm] or with hypozincaemia (less than 14 mumol/L).(ABSTRACT TRUNCATED AT 250 WORDS)

Acrodermatitis↗
PubMed1992

Persistent diarrhoea: factors affecting absorption and clinical prognosis during management with a rice-based diet.

Twenty-six persistent diarrhoea patients aged 4 to 18 months were treated with a diet prepared with rice powder, soya oil, glucose, egg white and water. Absorption of macronutrients was estimated in a 72 h balance study and clinical response was examined during one week of dietary treatment. Nutrient absorption was compared with that of 25 healthy age-matched controls treated with the same diet. Twenty-one patients (81%) recovered from diarrhoea within seven days. Absorption of nutrients was significantly reduced among the persistent diarrhoea patients. More malnourished patients had a significantly reduced absorption of nutrients except carbohydrate and an increased severity and longer duration of diarrhoea. Total gut transit time had significant association with nutrient absorption in the persistent diarrhoea patients. The period of recovery negatively correlated with coefficient of absorption and positively with initial stool weight. Failure to recover was associated with severity of diarrhoea and systemic infection. The study indicates that nutrient absorption is significantly reduced in patients with persistent diarrhoea and nutritional status, and that initial purging rate and intestinal hurry are significantly related to the prognosis and nutrient absorption.

Arm↗
PubMed1992

Effect of Vibrio cholerae-L-asparaginase on surface structure of splenic lymphocytes.

The surface ultrastructure of splenic lymphocytes and rosetting properties of lymphocytes of Swiss mice were studied under scanning electron microscope following transplantation of Dalton's lymphoma and ascites fibrosarcoma tumour cells and administration of Vibrio cholerae-L-asparaginase. The results were compared to those obtained with the standard Escherichia coli-L-asparaginase. The surface structure of the lymphocytes (T cells) following L-asparaginase administration was not so different from that of normal lymphocytes. V. cholerae-L-asparaginase did not cause higher number of rosette formation in T cells as compared to the normal group. The study thus revealed that V. cholerae-L-asparaginase did not have a significant stimulatory or non-immunosuppressive effect on the lymphocyte functions.

Animals↗
PubMed1992

Induction and regulation of alpha-amylase synthesis in a cellulolytic thermophilic fungus Myceliophthora thermophila D14 (ATCC 48104).

The alpha-amylase enzyme synthesis was higher when M. thermophila D-14 (ATCC 48104) was grown in culture medium incorporated with starch or other carbohydrates containing maltose units. Maximum enzyme production was attained with 1% starch followed by a gradual decrease with increasing concentration. Marked decrease in alpha-amylase synthesis occurred with the addition of glucose to the culture medium and this decreasing activity was proportional to the concentration of glucose. The enzyme synthesis was resumed as soon as the glucose concentration fell below a critical level. The addition of cAMP did not eliminate the repressive activity of glucose. The findings suggest that extracellular alpha-amylase synthesis in M. thermophila D-14 was inducible and subject to catabolite repression.

Enzyme Induction↗
PubMed1991

Serum trace elements and Cu/Zn ratio in breast cancer patients.

Serum copper, zinc, and the Cu/Zn ratio were measured in 55 patients with breast disease (20 with benign breast diseases and 35 patients with breast cancer) and 30 controls. The mean serum copper levels were higher in breast cancer than in benign breast diseases (167.3 micrograms/dl vs. 117.6 micrograms/dl) (P less than 0.001) and controls (167.3 micrograms/dl vs. 98.8 micrograms/dl) (P less than 0.001). Patients with advanced breast cancer had higher serum copper levels than did patients with early breast cancer (177.9 micrograms/dl vs. 130.4 micrograms/dl) (P less than 0.001). The mean serum zinc levels were lowered only in patients with advanced breast cancer as compared with controls (88.6 micrograms/dl vs. 115.1 micrograms/dl) (P less than 0.001). Serum zinc levels were not decreased in patients with early breast cancer and benign breast diseases. The Cu/Zn ratio was increased in breast cancer patients (1.91 vs. 0.86) (P less than 0.001) but not in patients with benign breast diseases. The precise mechanisms responsible for the alterations in trace element levels in breast cancer patients are still unclear and require further evaluation. However, the serum copper levels and the Cu/Zn ratio may be used as biochemical markers in these patients.

Adult↗
PubMed1991

Lipoxygenase: a new pathway for 2-aminofluorene bioactivation.

Soybean lipoxygenase mediated co-oxidation of 2-aminofluorene (2-AF), a putative carcinogen and teratogen, was examined. 2-AF metabolism was followed spectrally as a decrease in absorbance at 286 nm. The enzymatic oxidation displayed a pH optimum at 9.5 with a Km of 0.27 mM and specific activity of 521.7 +/- 46.6 nmol/min per nmol of enzyme. The generation of electrophilic 2-AF intermediate(s) capable of covalent binding to macromolecules was also investigated radiometrically. Significant binding to protein and calf thymus DNA was observed, suggesting clearly bioactivation of 2-AF. Several classical lipoxygenase inhibitors caused a marked inhibition of 2-AF oxidation as well as covalent binding to protein and DNA. These results strongly suggest that lipoxygenase is capable of 2-AF metabolism and this may represent another pathway for bioactivation of arylamines.

Animals↗
PubMed1991

In vitro DNA synthesis by isolated preantral to preovulatory follicles from the cyclic mouse.

In recent studies, we have shown that the smallest preantral follicles in the cyclic hamster increase DNA synthesis in the periovulatory period in response to surge levels of FSH. The current investigation was designed to determine whether the same phenomenon occurs in the cyclic mouse. Intact mouse follicles were isolated with watchmaker forceps (stages 4-6) or by enzymatic digestion (stages 1-4) at 0900 h and 1500 h on each day of the 5-day estrous cycle. The isolated follicles were classified into 6 stages: stages 1 and 2: follicles with 1 and 2 layers of granulosa cells; stage 3: follicles with 3 or more layers of granulosa cells and formation of theca; stages 4-6: incipient, small, and preovulatory antral follicles. The follicles at each stage were incubated for 3 h with [3H]thymidine. DNA content in stages 1-4 of follicles remained unchanged during the estrous cycle; for stages 5 and 6, DNA content was higher on the afternoon of proestrus than on other days of the cycle. Incorporation of [3H]thymidine for stages 1-3 (preantral follicles) started to increase at 1500 h of proestrus and peaked at 0900 h on estrus, whereas for stages 4-6, DNA synthesis peaked on proestrus (1500 h) and then fell by the morning of estrus. Thus, the rate of DNA replication in preantral and antral mouse follicles were different. Similarities and differences in folliculogenesis between mouse and hamster are discussed. These results suggest that DNA synthesis and the growth of all stages of follicles in the cyclic mouse may be associated with changing levels of periovulatory gonadotropins.

Animals↗
PubMed1991

In vitro effects of epidermal growth factor, insulin-like growth factor-I, fibroblast growth factor, and follicle-stimulating hormone on hamster follicular deoxyribonucleic acid synthesis and steroidogenesis.

Preantral (stages 1-6) and antral (stages 7-10) follicles from proestrous hamsters were exposed for 24 h to 1, 5, 10, 50, and 100 ng/ml of epidermal growth factor (EGF), insulin-like growth factor-I (IGF-I), and fibroblast growth factor (FGF) and 1 microCi [3H]thymidine to determine the rate of DNA replication. FSH (100 ng/ml) was used as a positive control. Synergism was also studied by using suboptimal doses of growth factors (1 ng/ml) and FSH (5 ng/ml). Optimal doses (50 ng/ml) of EGF, IGF-I, and FGF, and 100 ng/ml FSH significantly enhanced follicular DNA replication, whereas suboptimal doses of FSH, EGF, and IGF-I affected only a few preantral stages, and FGF was totally ineffective. FGF significantly inhibited DNA synthesis induced by a suboptimal dose of EGF but did not affect IGF-I-induced DNA replication. Paradoxically, a combination of suboptimal doses of all three growth factors significantly (p less than 0.05) stimulated DNA synthesis for all stages; FSH (5 ng/ml) had no additive effect. FSH significantly stimulated follicular progesterone (P4), androstenedione (A), and estradiol-17 beta (E2) accumulation, but significant P4 accumulation from stages 3-10 was observed only after optimal EGF exposure; A and E2 accumulations were unaffected by any of the growth factors. These results indicate that EGF, IGF-I, and FGF stimulate DNA replication to hamster preantral and antral follicles, and may play roles as intraovarian factors regulating folliculogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Mediation of follicle-stimulating hormone action on follicular deoxyribonucleic acid synthesis by epidermal growth factor.

FSH stimulates DNA synthesis by hamster preantral follicles both in vivo and in vitro, and the in vitro mitogenic effect of FSH is effectively reproduced by epidermal growth factor (EGF). To determine whether follicular EGF is the intracellular transducer of FSH action on hamster preantral follicles, intact follicles at stages 1 to 7 (stages 1-4 = preantral follicles 1-4 layers of granulosa cells, respectively, and no theca; stages 5-6 = 5-6 and 7-8 layers granulosa cells, respectively, and developing theca; and stage 7 = follicles with incipient antrum) were cultured for 24 h in a serum-free culture medium in the absence or presence of 100 ng FSH, 50 ng EGF, 50 ng transforming growth factor-alpha (TGF alpha), or 1 mumol 8-Br-cAMP and challenged with 50 microliters polyclonal antimurine EGF antiserum; the rate of DNA synthesis was determined by [3H]thymidine incorporation. FSH, EGF, and TGF alpha significantly (P less than 0.05) stimulated follicular DNA synthesis; TGF alpha per se was less effective than either FSH or EGF. However, both FSH- and EGF-induced DNA synthesis was drastically attenuated by EGF antiserum; TGF alpha effect remained undisturbed. Interestingly antibody inhibition of FSH-induced DNA synthesis was totally reversed by coexposure to TGF alpha. Follicular DNA synthesis for most stages was stimulated by Br-cAMP, but the effect was significantly (P less than 0.05) inhibited by EGF antibody. Moreover, follicles at different stages responded to EGF with different latency. These results strongly suggest that FSH-induced follicular DNA synthesis in the hamster is mediated by follicular EGF and the pathway of events is FSH action----cAMP production----EGF synthesis----cell proliferation.

Animals↗
PubMed1991

Induction of L-asparaginase synthesis in Vibrio proteus.

Studies on L-asparaginase synthesis in V. proteus showed increased synthesis in cultures grown under conditions of moderate aeration (P less than 0.005) after oxygen had been used up from the medium. Addition of sodium lactate to the medium at a concentration of 80 mu mole/ml, stimulated L-asparaginase synthesis (2.2 times over control) in moderately-aerated cultures (P less than 0.001). The substrate L-asparagine induced enzyme synthesis when growth conditions were made anaerobic or lactate was incorporated into the medium (3.8 times increased enzyme synthesis over control).

Asparaginase↗
PubMed1991

Persistent diarrhea: total gut transit time and its relationship with nutrient absorption and clinical response.

The study was undertaken to better understand the role of total gut transit time (TGTT) on the absorption of nutrients in patients with persistent diarrhea. Twenty-six boys aged 3-18 months with persistent diarrhea and 25 age-matched healthy controls were studied. Their TGTT was measured with charcoal markers during their treatment with a diet made up with rice powder soya oil, glucose, and egg white. Coefficients of absorption of nutrients were estimated in a 72-h balance study. The median TGTTs in patients and controls were 5 and 11.6 h, respectively. Among the patients, the TGT correlated significantly with absorption of total energy (p less than 0.01), absorption of fat (p less than 0.01), stool frequency (p less than 0.01), and stool weight during the 1st 24 h (p less than 0.01). Coefficients of absorption of energy, fat, and carbohydrate were significantly different among the patients above or below the median transit time (5 h). None of these relationships was present among the healthy controls. The TGTT was negatively associated with the duration of clinical recovery. The results of this study suggested that intestinal transit time is an important factor for absorption of nutrients that may influence clinical recovery in patients with persistent diarrhea.

Campylobacter Infections↗
PubMed1990

Purification and properties of an extracellular endoglucanase from Myceliophthora thermophila D-14 (ATCC 48104).

An extracellular endoglucanase (1,4-beta-glucanohydrolase, EC 3.2.1.4) produced by Myceliophthora thermophila D-14 (ATCC 48104) has been purified to homogeneity by ammonium sulphate precipitation and two consecutive ion-exchange chromatographic steps on DEAE-Sephadex A-50 columns. The enzyme was purified 13.8-fold and was homogeneous by analytical PAGE and SDS-PAGE. It has a high apparent Mr, of about 100,000. The pH and temperature optima for its activity were 4.8 and 65 degrees C respectively. The Km of the purified enzyme for CMC (sodium salt) was 3 mg ml-1. The enzyme displayed low activity toward salicin and p-nitrophenyl beta-D-glucoside. The activity was enhanced in the presence of Na+, K+ and Ca2+ but effectively inhibited by Hg2+, Fe2+, Mg2+, Cu2+ and NH4+. Inhibition studies indicated that the enzyme may be a metalloprotein and/or that it requires metal ions for its optimum activity.

Cellulase↗
PubMed1990

Persistent diarrhoea: clinical efficacy and nutrient absorption with a rice based diet.

Twenty six infant boys, aged 4 to 18 months, suffering from persistent diarrhoea and 25 age matched healthy controls without diarrhoea were given a diet based on rice powder, egg white, glucose, and soya oil. The clinical efficacy of the diet was studied and a 72 hour metabolic balance study was done. Twenty one patients recovered from diarrhoea within seven days. Median coefficients of absorption of nutrients in persistent diarrhoea patients were 68.0% (range 28.0 to 92.0) for total energy, 60.0% (range 21.0 to 97.0) for fat, 53.0% (range -122.0 to 82.0) for nitrogen, and 81.0% (range 23.0 to 97.0) for carbohydrates. The corresponding values among the control subjects were 90.0% (range 76.0 to 99.0), 95.0% (range 71.0 to 99.0), 70.0% (range 10.0 to 95.0), and 93.0% (range 85.0 to 98.0) respectively. Absorption of all macronutrients in the control subjects was on average significantly higher than in the patients. Nutrient absorption is substantially reduced in persistent diarrhoea and a rice based diet is clinically effective in most patients.

Bangladesh↗
PubMed1990

Immunohistochemical localization of epidermal growth factor-like activity in the hamster ovary with a polyclonal antibody.

A polyclonal antibody to murine epidermal growth factor (EGF) was generated in rabbits and characterized by RIA, Western blots, and dot blotting. The antibody detected as little as 0.01 ng of mouse EGF in dot blots at 1:100,000 dilution and 5 pg of EGF in RIA at 1:50,000 dilution; it did not cross-react with transforming growth factor-alpha, insulin-like growth factor, or fibroblast growth factor. Ovarian EGF content peaked (17 +/- 2 pg/nonluteal ovary) on Day 1 (estrus as determined by copious vaginal discharge) and declined by DAy 3 as measured by RIA of immunoaffinity-purified ovarian extract. Frozen sections of hamster ovaries were stained immunohistochemically for EGF using a Zymed kit. Intense red staining specific for EGF was localized only in granulosa cells of small (1-2 layers of granulosa cells) and medium (3-6 layers of granulosa cells) preantral follicles; moderate staining was observed in the granulosa and theca cells of small antral follicles. Staining intensity faded in granulosa and theca cells of large antral follicles, especially on Day 4 (proestrus) and disappeared in pyknotic granulosa cells of atretic follicles. Follicular EGF staining peaked on Days 1 and 2 and thereafter declined to low levels. On Day 2, oocytes of the primordial follicles showed distinct coloration. Sections of Day 2 ovary incubated with preneutralized antibody or normal rabbit IgG did not show any coloration. For intact hamsters, 10 micrograms of follicle-stimulating hormone (FSH), twice daily for Days 1 and 2, intensified EGF staining in granulosa cells compared with corresponding untreated Day 3 hamsters, whereas similar treatment with luteinizing hormone for 2 days expanded the interstitium with localized staining of interstitial cells only around follicles with 2 and 3 layers of granulosa cells and lacking theca. Hypophysectomy for 13 days resulted in almost complete absence of EGF-specific staining in the remaining nonatretic follicles; however, exogenous FSH (5 micrograms, twice daily) for 2 days dramatically increased staining intensity associated with newly developed follicles. Luteinizing hormone (0.4 micrograms, twice daily) for 2 days, however, induced significant development of only the interstitium with increased staining of small preantral follicles. These results provide strong evidence for the presence of EGF-like activity in hamster ovarian follicles and suggest that its expression is controlled by gonadotropins, especially FSH.

Animals↗
PubMed1990

Genetic differences in follicular DNA synthesis between two strains of hamsters.

This study was designed to compare our previous results on ovarian follicular DNA synthesis by hamsters obtained from Sasco Laboratories with a different breeding colony: Harlan. Follicles from proestrous Harlan hamsters required twice as much [3H] thymidine and a minimum of 4 hr of in vitro exposure to 100 ng of ovine follicle-stimulating hormone (FSH) before a significant increase in DNA synthesis was elicited compared with 30-120 min for the Sasco breed. Peak responsiveness to FSH was observed at 8-hr incubation for the Harlan strain with significant increases in DNA per follicle at 8-12 hr. Both strains increased DNA synthesis with as little as 25 ng of ovine FSH and the response was elicited in all growing follicles, from preantral stages with one to four layers of granulosa cells, lacking theca (Stages 1-4) to mature antral follicles (Stages 8-10). A recombinant bovine FSH, devoid of luteinizing hormone activity, was not as effective as ovine FSH (which has 4% luteinizing hormone contamination) in stimulating DNA synthesis by large preantral and antral follicles. In vitro responsiveness to ovine FSH was abolished in the absence of Ca2+ in the culture medium and 0.05 mM Ca2+ was the optimal amount. For both strains of hamsters, the highest rate of DNA synthesis in response to endogenous gonadotropins was on the morning of estrus--when the second surge of FSH was in progress--and Harlan follicles in vitro also showed maximal stimulation by FSH on this day. Where the two strains differed was that the Harlan strain did not show an increase in follicular DNA synthesis on the afternoon of proestrus--when the preovulatory increase in gonadotropins commenced. When expressed as DNA per follicle, DNA approximately doubled from Stages 1 to 5 and then entered a new growth phase at Stage 6 (large preantral follicles) with a steeper increase. Collectively, these experiments show that strain characteristics can alter the latency and degree of follicular DNA replication in response to endogenous or exogenous FSH.

Animals↗
PubMed1990

Antitumor activity of L-asparaginase from Cylindrocarpon obtusisporum MB-10 and its effect on the immune system.

L-Asparaginase from Cylindrocarpon obtusisporum MB-10 inhibits the growth of Ascites Fibrosarcoma and Dalton's Lymphoma tumor cells in vivo and significantly increases the survival rate of tumor bearing mice. The enzyme-treated normal mice become more healthy and survive longer than their usual life span. The spleen size of normal animals treated with L-asparaginase become larger, and the number of their rosetting T-lymphocytes along with the capacity of SRBC constellation gets increased. The surface topography of splenic T-lymphocytes of enzyme-treated mice exhibits some extensions of different parts of the membrane with ruffling of surface and formation of innumerable blebs, foldings, microvilli, etc. The adherence of leukocytes of peritoneal exudate cells of these mice is also enhanced. All results suggest that C. obtusisporum MB-10 L-asparaginase is active against tumors and non-immunosuppressive, and it deserves to be an immunotherapeutic agent.

Animals↗