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Biomedical subjects

S S Guraya

Publications and source records attributed to S S Guraya.

At least 19 recordsLinked to original sources
PubMed2005

Extracts of Azadirachta indica and Melia azedarach seeds inhibit folliculogenesis in albino rats.

The seed oil of Azadirachta indica A. Juss (neem) is used in traditional medicine for its antidiabetic, spermicidal, antifertility, antibacterial, and wound healing properties. The present study was undertaken to investigate the quantitative aspects of follicular development in cyclic female albino rats (135 +/- 10 g; 8 groups with 6 animals in each group) after oral administration of polar (PF) and non-polar (NPF) fractions of A. indica seed extract at 3 and 6 mg kg body weight-1 day-1 and Melia azedarach Linn. (dharek) seed extract at 24 mg kg body weight-1 day-1 for 18 days. The extracts were prepared using a flash evaporator at 35 degrees C and then dissolved in olive oil to prepare doses on a per kg body weight basis. There was a significant reduction (P = 0.05) in the number of normal single layered follicles (A. indica: 0.67 +/- 0.33 and 4.67 +/- 2.03 after 3 and 6 mg/kg NPF, and 3.33 +/- 1.67 and 1.00 +/- 1.00 after 3 and 6 mg/kg PF vs control: 72.67 +/- 9.14 and M. azedarach: 0.60 +/- 0.40 and 1.80 +/- 1.2 after 24 mg/kg PF and NPF, respectively, vs control: 73.40 +/- 7.02) and follicles in various stages (I-VII) of follicular development in all treatment groups. These extracts also significantly reduced (P = 0.05) the total number of normal follicles in the neem (14.67 +/- 5.93 and 1.00 +/- 1.00 after 3 and 6 mg/kg PF and 3.67 +/- 0.88 and 5.33 +/- 2.03 after 3 and 6 mg/kg NPF) and dharek (13.00 +/- 3.58 and 14.60 +/- 2.25 after 24 mg/kg NPF and PF) treatments compared to control (216.00 +/- 15.72 and 222.20 +/- 19.52, respectively). Currently, indiscriminate use of persistent and toxic rodenticides to control rodent populations has created serious problems such as resistance and environmental contamination. Therefore, it becomes necessary to use ecologically safe and biologically active botanical substances that are metabolized and are not passed on to the next trophic level, and that interfere with the reproductive potential particularly growth and differentiation of follicles. This may help elevate the socio-economic status of the country. Thus, the present study is an attempt to investigate the effects of A. indica and M. azedarach seed extracts on reproduction of albino rats.

Animals↗
PubMed2000

Cellular and molecular biology of capacitation and acrosome reaction in spermatozoa.

A comparative account is given of advances in cellular and molecular biology of capacitation and acrosome reaction in spermatozoa by comparing and contrasting their biochemical and physiological changes in response to various factors in vivo and in vitro. It can now be stated that phenomena of sperm capacitation and acrosome reaction are endogenous molecular events occurring at the membrane level which can be modulated by external environmental factors. The molecular mechanisms and the signal transduction pathways mediating the process of capacitation and acrosome reaction are only partially defined and appear to involve modification of intracellular Ca2+ and other ions, lipid transfer, and phospholipid remodeling in the sperm plasma membrane as well as changes in protein phosphorylation. Evidences for the involvement of cAMP-dependent kinase pathway in the acrosome reaction are discussed. The mediation of one or more external signals by the sperm plasma membrane appears to activate this pathway after or simultaneously with the influx of Ca2+. Concurrent with or following entry of Ca2+, adenylate cyclase is activated, leading to increased concentrations of cAMP-activation of cAMP-dependent kinase and protein phosphorylation; the identity of such proteins and their role in the acrosome reaction must be determined. The roles of biological effectors of the acrosome reaction, such as ZP3 and follicular fluid are still to be defined at the molecular level. The gaps in our knowledge about the cellular and molecular aspects of capacitation and acrosome reaction are emphasized.

Acrosome Reaction↗
PubMed1999

Role of estradiol in the capacitation and acrosome reaction of hamster epididymal spermatozoa in the isolated uterus of mice incubated in vitro.

The site of sperm capacitation, the agents and mechanisms causing capacitation and acrosome reaction (AR) in vivo are not well understood. The female reproductive tract has been reported to play a key role during capacitation and AR. Some experiments were carried out on the capacitation and AR of hamster epididymal spermatozoa in the estrogen and progesterone dominated uterus (estrous and diestrous respectively) albino mice, incubated in TALP without calcium and BSA. Also the effect of estradiol (200 micrograms/ml) supplemented to TALP, on capacitation and AR was examined. Capacitation and AR of hamster spermatozoa incubated in the isolated uterus of both estrous and diestrous mice were significantly (P < 0.05) higher in the presence of exogenous estradiol than that in its absence. Acrosome shedding occurred earlier i.e. at 3rd hour as compared to the in vitro studies where it occurred at 5th hour. The present study thus reveals that uterus of both estrogen and progesterone dominated mice play an important role in the induction of capacitation and AR. The addition of estradiol might have the influence on the synthesis of uterine proteins of mice which might be important for capacitation and AR.

Acrosome Reaction↗
PubMed1997

Atropine and testosterone propionate induced atretic changes in granulosa cells of house rat (Rattus rattus) ovary.

Degenerative changes in membrana granulosa of ovaries in R. rattus have been studied using scanning electron microscopy. Ovaries from rats treated with atropine (300 mg/kg body weight) and testosterone propionate (10 IU) were used to study sequential course of atresia in granulosa cells. Granulosa cells undergoing atresia showed degenerative changes in following order i) loosening of intercellular matrix, ii) changed morphology and texture of secretory granules, iii) destabilization of granulosa cell membranes, iv) erosion of cell membrane, v) formation of specific degenerative belts, vi) pycnosis, vii) ghost cell formation and their subsequent mixing in hazzy follicular fluid of cyst. Phenomenon of atresia, its duration, course and underlying causes have been discussed.

Animals↗
PubMed1995

Induction of buffalo (Bubalus bubalis ) sperm capacitation and acrosome reaction in the excised reproductive tract of hamsters.

A study was conducted on the induction of buffalo sperm capacitation and acrosome reaction in the excised reproductive tract of hamsters at the estrogen- and progesterone-dominated stages of estrus. The percentages of the maximum capacitation and acrosome reaction were significatly (P < 0.01) higher for spermatozoa incubated in the uterus with oviducts of estrogen dominated hamsters compared with those incubated in BWW medium in a test tube (64.6%, 60.2%; 16.2%, 14.7%). Buffalo spermatozoa incubated in the uterus and oviducts of progesterone-dominated hamsters showed significantly (P < 0.01) lower capacitation and acrosome reaction rates than those incubated in the uterus and oviducts of estrogen-dominated hamsters (34.8%, 34.3%: 64.6%, 60.2%). The percentage of capacitation and acrosome reaction in spermatozoa were significantly (P < 0.01) more when incubated in the uterus plus oviducts than without the oviduct irrespective of whether the reproduct tract of hamster was estrogen- or progesterone-dominated. The time for the onset of maximum capacitation and acrosome reaction was reduced from 12 to 10 h when the spermatozoa were incubated in the hamster reproductive tract rather than in BWW medium in test tubes. The significance of the results in relation to hormonal regulation of sperm capaciation and acrosome reaction are also discussed.

Journal Article↗
PubMed1995

The comparative cell biology of accessory somatic (or Sertoli) cells in the animal testis.

A comparative account is given of recent advances in the cell biology of testicular accessory somatic (or Sertoli) cells in mammals, nonmammalian vertebrates, and invertebrates by comparing and contrasting their structure and function. Their structure is discussed in relation to the nucleus, cytoplasmic organelles, and inclusions (lipids, the cytoskeleton, junctional complexes, and blood-testis barrier, which show great diversity and a variable testicular architecture), and mode of spermatogenesis. A very limited somatic cell-germinal association or its complete absence is observed in some groups of invertebrates. Wherever the somatic accessory cells are present, their comparative functions are discussed in relation to (1) mechanical support and nutrition; (2) translocation of germ cells; (3) paracrine regulation and a combination of male germ cell proliferation and differentiation by secretion of regulatory proteins, including peptide growth factors and hormones; (4) phagocytosis; (5) steroid hormone synthesis and metabolism; and (6) spermiation. Comparative cellular and molecular aspects of Sertoli cell-germ cell and peritubular cell interactions and the regulatory (hormonal) mechanisms involved as well as gaps in our knowledge about the molecular aspects of these interactions are emphasized for a better understanding of diversity in the patterns and regulation of spermatogenesis in animals.

Animals↗
PubMed1995

Correlative histochemical and biochemical studies on acetylcholinesterase activity during ovulation in the rat.

A correlative histochemical and biochemical study has been made of the changes in acetylcholinesterase (AChE)-positive sites during ovulation induced in immature female albino rats with exogenous gonadotrophins. Acetylcholinesterase is the marker for cholinergic innervation. In histochemical observations, AChE+ve sites were localized in typical perivascular position and the intensity and number of enzyme-positive sites around the Graafian follicle gradually increased during follicular maturation and ovulation but stromal AChE-activity did not show any appreciable change. Biochemical estimation of the enzyme supports these observations. The electronmicroscopic and histological observations of the structural changes in nerves accompanying ovulation have also been enumerated and the role of cholinergic nerves in neuromuscular control of ovulation is discussed.

Acetylcholine↗
PubMed1993

Follicular growth patterns in the house rat (Rattus rattus).

A histomorphometrical study has been made of the ovarian follicles in the house rat (Rattus rattus) during estrous cycle, pregnancy and after treatment with FSH, LH and estrogen. The relationships between oocyte and follicle, oocyte nucleus and follicle, oocyte nucleus and oocyte have been analysed statistically. The logarithmic transformation of data on these components of the ovary yielded as regression: log y = a+b log x parabolic form in the control,. pregnant, FSH and estrogen treated groups of rats. A linear (y = a+bx) relationship between oocyte and follicles was obtained in the LH-treated ovaries. This study provides a better method of statistical evaluation for follicular growth patterns in normal and hormone treated animals. The results have been discussed in relation to the physiological functions of follicles.

Animals↗
PubMed1993

Changes in catalase activity during follicular growth, atresia and luteinization in rat ovary.

Quantitative changes have been observed in the catalase activity during follicular growth, induced atresia and in corpora lutea of cycle and pregnancy. Large growing and preovulatory follicles showed higher enzyme activity as compared to the smaller follicles; the activity was mainly present in the thecal layer of the preovulatory follicle. After the blockade of ovulation with barbiturate, the activity increases significantly in the whole follicle and also in the thecal layers till third day of ovulation and afterward it declines on 5th day, suggesting that rise in catalase activity may exert a protective function against lytic actions of peroxide which is known to be produced in the ovary during several metabolic and steroidogenic events. The corpora lutea of the cycle showed significantly less enzyme activity than the corpora lutea of pregnancy. The significance of catalase activity during follicular and corpus luteum degeneration is discussed.

Animals↗
PubMed1992

A simple staining procedure for detecting the true acrosome reaction in buffalo (Bubalus bubalis) spermatozoa.

A simple dual staining procedure for detecting the true acrosome reaction in dried smears of buffalo spermatozoa is described. Trypan blue is used first to differentiate live from dead spermatozoa and the dried smears which have been prepared are stained with Giemsa for acrosome evaluation. Four categories of spermatozoa were recognized: A) live, intact acrosome (acrosome pink, postnuclear cap clear); B) dead, intact acrosome (acrosome pink, postnuclear cap blue); C) live, detached acrosome (acrosome clear, postnuclear cap clear); and D) dead, detached acrosome (acrosome clear, postnuclear cap blue). The procedure is simple, rapid and convenient for assessing true acrosome reaction in buffalo spermatozoa. Simultaneous assessment of sperm viability and its acrosomal status in dried smears makes this procedure attractive because the true acrosome reaction can be studied thoroughly at a later state after the incubation period.

Acrosome↗
PubMed1992

Lectin staining studies on follicular atresia in house rat (Rattus rattus).

Topographic distribution of terminal and intercalary carbohydrate moieties were studied using horseradish peroxidase conjugated Glycine max (GMA), Arachis hypogea (PNA), Lotus tetragonolobus (LTA), Bandirarea simplicifolia (BSA), and Dolichos biflorus (DBA) agglutinins. N-Gal NAc, alpha-D-Gal, alpha-L-Fuc, D-Gal (beta-1-3)-D-Gal NAc, and alpha-beta-D Gal NAc linked glyco-conjugates were exposed during follicular atresia in oocyte, zona pellucida and granulosa cells. Theca interna and interstitial gland tissue revealed homology in lectin binding.

Agglutination↗
PubMed1992

Chemotactic detection of incipient ovarian follicular atresia.

Chemotactic activity was measured in the follicular fluid collected from normal and atretic Graafian follicles isolated from the rat ovaries. The atresia of Graafian follicles was induced by pentobarbitone injections for 3 days beginning the day of proestrous. The chemotactic activity, as measured by direct morphological evaluation of cellular locomotion of individual cells and Boyden leading front assay, was significantly higher in follicular fluid from atretic follicles and it showed a progressive increase from day 1 to day 3 of blockade of ovulation. In vitro exposure of blocked follicles to PMSG and hCG on day 1, 2 and 3 failed to alter the chemotactic response of leukocytes towards follicular fluid of atretic follicles. Increased chemotaxis in the follicular fluid after 24 hr of blockade of ovulation appears to form an important criterion to identify atretic follicles well in advance, before the morphological symptoms of degeneration become apparent and the incipient change once induced in follicles is not reversed by gonadotropins.

Animals↗
PubMed1991

Histochemical and biochemical studies on esterase activity in the rat ovary.

A correlative histochemical and biochemical study has been made of the changes in esterase positive sites in immature (10-, 20- and 30-days old), mature normal cycling (3-, 5- and 8-months-old), pregnant and lactating rat ovaries. The typical perivascular esterase-positive sites localized in the hilar portion, branch along the blood vessels and traverse into medullary and cortical portions of the ovary. The stromal vascularity surrounding the normal developing follicles, corpora lutea, atretic follicles and interstitial gland tissue showed rich activity of this enzyme system. On semiquantitative basis the number, intensity and quantity of esterase-positive sites vary with the maturation and reproductive states of the rat. The administration of estradiol-17 beta increased the fine perifollicular and theca externa perivascular esterase-positive sites, whereas atropine and reserpine affected severely both the large and fine meshwork of esterase-positive sites. Biochemical estimates of acetylcholine esterase activity endorse these histochemical observations. The possible roles of AChE activity in varied ovarian functions are discussed.

Acetylcholinesterase↗
PubMed1991

Correlation between steroids and plasmin in rat ovaries during ovulatory process.

Progesterone (0.5 mg/rat) and estradiol-17 beta (10 micrograms/rat) injected(im) to adult female albino rats on the morning of proesterous significantly enhanced the ovarian plasmin activity as measured by the fibrin plate method at the time of ovulation which was confirmed to be at 2.30 a.m. by estimation of ovarian plasmin activity at definite intervals before and after ovulation. The ovarian plasmin activity showed a gradual increase towards ovulation and reached a maximum level at 2.30 a.m. and again decreased after ovulation. However, the nonsteroidal estrogen antagonist, tamoxifen induced inhibitory effects on the ovarian plasmin activity as compared to control and estradiol-17 beta treatment. Thus these studies reveal a positive relationship between steroids and the ovarian plasmin activity during ovulation.

Animals↗
PubMed1991

Histochemical changes in adenosine triphosphatase activity during folliculogenesis and corpus luteum formation and regression in the rat ovary.

Histoenzymological changes in Adenosine triphosphatase (ATPase) activity were studied during folliculogenesis in immature and mature rat ovary. Its presence in oocytes of small follicles and absence in those of large follicles postulate a correlation between their absorptive mechanism during the development of the oocyte. The presence of ATPase activity in the theca, corpora lutea and interstitial gland tissue may be related to the vascular endothelium which is associated with the transport system across the membrane.

Adenosine Triphosphatases↗