Biomedical subjects

S Coskun

Publications and source records attributed to S Coskun.

29 records · Page 2Linked to original sources

PubMed1998

Presence of leukemia inhibitory factor and interleukin-12 in human follicular fluid during follicular growth.

PROBLEM: Cytokines have been shown to be present in human follicular fluid and have regulatory functions on follicular maturation. The presence of leukemia inhibitory factor (LIF) and interleukin (IL)-12 in human follicular fluid obtained at different stages of maturation was investigated. METHOD OF STUDY: Follicular fluids and granulosa cells were obtained from preovulatory and immature follicles. Follicular fluids from both groups were assayed for IL-12 and LIF by enzyme-linked immunosorbent assay. Granulosa cells from preovulatory and immature follicles were treated with human chorionic gonadotropin (hCG) in vitro and subsequent LIF and IL-12 production were measured. RESULTS: The average concentration of LIF was significantly higher in preovulatory follicles (7.6 +/- 1.3 pg/ml, n = 24) than in immature follicles (2.0 +/- 1.3 pg/ml, n = 6). The concentration of IL-12 was significantly higher in follicular fluid obtained from immature follicles (10.9 +/- 5.0 pg/ml) than in preovulatory follicles (1.3 +/- 0.4 pg/ml). hCG only stimulated LIF production from mature granulosa cells; it had no effect on IL-12 production. CONCLUSIONS: IL-12 and LIF are present in follicular fluid and their levels are regulated differently during follicular maturation. hCG stimulates LIF production from granulosa cells in vitro.

Cells, Cultured↗

PubMed1998

Effect of human chorionic gonadotropin on cytokine production from human endometrial cells in vitro.

PROBLEM: To examine whether human chorionic gonadotropin (hCG) is involved in the regulation of interleukin (IL)-6, tumor necrosis factor (TNF)-alpha, and leukemia inhibitory factor (LIF) secretion from cultured human endometrial cells. METHOD OF STUDY: A mixed population of endometrial cells from six in vitro fertilization/embryo transfer patients was cultured and incubated with various doses of hCG (0, 1, 10, 50, 100, and 500 IU/ml) for 24 hr. IL-6, TNF-alpha, and LIF levels in the culture medium were measured with enzyme-linked immunosorbent assay. RESULTS: IL-6 and TNF-alpha levels were stimulated by hCG in a dose-dependent manner. Stimulation of IL-6 and TNF-alpha levels by 500 IU/ml of hCG increased their production by 3.7- and 2.8-fold, respectively (P < 0.05). Stimulation of IL-6 by 100 IU/ml of hCG was also significant (P < 0.05). However, there was no significant effect of hCG on LIF secretion by endometrial cells (P = 0.31). CONCLUSIONS: hCG is involved in the regulation of endometrial cytokine production from human endometrial cells in vitro. This finding supports the recently emerging notion that hCG could have important local roles within the uterus besides its well-known luteotrophic role on the corpus luteum for maintenance of pregnancy.

Cells, Cultured↗

PubMed1997

Pregnancy after transfer of embryos which were generated from in-vitro matured oocytes.

In-vitro maturation of human oocytes is an important technique in assisted reproduction due to its potential for reducing the use of fertility drugs. We offered this technique as an alternative to cancelling the cycle to a patient who was at risk of ovarian hyperstimulation syndrome (OHSS) after treatment with gonadotrophin-releasing hormone analogue (GnRHa) and human menopausal gonadotrophin (HMG). The patient had 40 visible antral follicles with a maximum diameter of 13 mm and an oestradiol concentration of 14,000 pmol/l on cycle day 12. Immature oocytes were aspirated transvaginally under ultrasound guidance. Ten cumulus-enclosed oocytes were harvested and nine of them completed nuclear maturation to metaphase II after 48 h in culture. By 18 h after an intracytoplasmic sperm injection (ICSI) procedure, seven of these metaphase II stage oocytes displayed two distinct pronuclei and two polar bodies. All fertilized oocytes but one underwent cleaveage; four of these were transferred 2 days later. Endometrial priming was initiated with 8 mg oestradiol valerate daily from the day of oocyte retrieval and 50 mg progesterone was injected i.m. daily starting 2 days after that. A single intrauterine sac was seen containing one fetus with positive fetal heart beat on ultrasound at 7 weeks of gestation. Unfortunately, the pregnancy ended at 24 weeks shortly after premature rupture of membranes; a live healthy-looking girl was delivered who died 18 days later.

Adult↗

PubMed1995

Mechanism of action of epidermal growth factor-induced porcine oocyte maturation.

EGF has been reported to promote oocyte maturation in several species, although the mechanism of action is not yet known. The present study is designed to determine the pathway used by EGF to enhance porcine oocyte maturation. Oocytes were aspirated from 2-5 mm follicles and cultured with various treatments in Medium-199 at 37 degrees C, 100% relative humidity, and 5% CO2 for 48 hr for the maturation study and 3 hr for intracellular cAMP measurement. Although treatment with 100 IU/ml hCG stimulated both intracellular cAMP formation and oocyte maturation, 10 ng/ml EGF stimulated oocyte maturation only. Dibutyryl cAMP (dbcAMP) inhibited oocyte maturation at 10(-5), 10(-4), and 10(-3) M concentration s in the control medium. However, in the presence of 10 ng/ml EGF, dbcAMP inhibited oocyte maturation only at a concentration of 10(-3) M. Increasing concentrations of EGF (i.e., 25 and 50 ng/ml) were ineffective in overcoming the inhibitory effect of dbcAMP at 10(-3) M. In contrast, EGF reversed the decreased maturation rate caused by transforming growth factor-beta. Phorbol myristate acetate (PMA), a tumor-promoting phorbol ester, enhanced the spontaneous maturation rate; 4 alpha-phorbol dideconoate, an inactive phorbol ester, did not show this effect. PMA- and EGF-stimulated porcine oocyte maturation is reversed by calphostin-C, a PKC inhibitor. In conclusion, EGF's promotional activity on porcine oocyte maturation is independent of the cAMP pathway and probably mediated by the PKC pathway.

Animals↗

PubMed1995

Regulation of cumulus cell steroidogenesis by the porcine oocyte and preliminary characterization of oocyte-produced factor(s).

This study was designed to investigate whether porcine oocytes produce a factor(s) that influences cumulus and mural granulosa cell steroid production and to characterize the biochemical nature and mode of action of a such factor(s). Porcine cumulus-oocyte complexes (COC) were collected from 2-5 mm follicles and cultured either intact or after oocytectomy for 48 h. Steroid levels were then measured in the culture media. Conditioned media, obtained by culturing denuded oocytes for 48 h, were subjected to heat treatment of charcoal extraction and utilized to culture intact and oocytectomized COC. FSH-stimulated progesterone, 20 alpha-OH-progesterone, and estradiol were significantly higher in oocytectomized vs. intact COC cultures. Denuded oocytes cultured with granulosa cells significantly inhibited progesterone production compared to control. Also, media conditioned with different numbers of denuded oocytes (0 to 300) significantly inhibited progesterone production by oocytectomized COC in a manner dependent on oocyte number. Charcoal extraction, but not heat treatment, significantly removed the inhibitory effect of the conditioned media on progesterone production by oocytectomized COC. Increased progesterone production by oocytectomized COC was not accompanied by a similar increase in cAMP formation. Heptanol, a gap junction blocker, did not alter progesterone production by intact COC. In conclusion, porcine oocytes secrete a factor(s) that inhibits cumulus and mural granulosa cell steroidogenesis. This factor(s) is heat stable but extractable by charcoal. The factor(s) appears not to be transferred to somatic cells via gap junctions, and its effect is downstream of cAMP formation.

Animals↗

PubMed1994

Effects of transforming growth factors and activin-A on in vitro porcine oocyte maturation.

Growth factors are known to regulate ovarian function. In the present study, effects of these growth factors, TGF-alpha, TGF-beta, and activin-A were tested on spontaneous porcine oocyte maturation. Cumulus-oocyte complexes (COC) were cultured in the presence of TGF-alpha, TGF-beta, and activin-A for 48 hr. Stages of meiotic maturation were assessed by staining with acetic orcein. Among these factors, only TGF-alpha significantly enhanced the maturation rate, whereas TGF-beta suppressed the spontaneous maturation rate. The site of action of TGF-alpha on COC and the interaction between TGF-alpha and EGF receptor was also examined. Denuded oocytes, alone or in coculture with cumulus cells, were cultured in the presence of TGF-alpha for 48 hr. TGF-alpha did not have any significant effect on denuded oocyte maturation. Heptanol was employed to investigate the role of gap junctions on TGF-alpha-induced oocyte maturation in COC. Although heptanol did not have any significant effect in the control medium, heptanol reversed the stimulatory effect of TGF-alpha on porcine oocyte maturation. TGF-alpha was able to displace 125I-EGF binding on COC. In conclusion, TGF-alpha enhances the spontaneous maturation of porcine oocytes by generating positive signal(s) in cumulus cells that are transferred to the oocyte via gap junctions. TGF-alpha shares the same receptor with EGF on porcine COC. TGF-beta, in contrast, inhibits porcine oocyte maturation.

Activins↗

PubMed1994

Inhibition of in vitro fertilization and early embryonic development in hamsters by gossypol.

We have previously reported an inhibitory effect of gossypol and its metabolite on bovine and mouse early embryonic development. In the present study, eggs were collected from oviducts of superovulated hamsters. Epididymal sperm were used for in vitro fertilization (IVF). Gossypol at 5, 10, and 30 micrograms/ml significantly inhibited the formation of 2 pronuclei by 45, 65 and 95%, respectively. On the first day of pregnancy, hamsters were given an intrauterine treatment of 200 micrograms of gossypol in 100 microliters of corn oil per uterine horn. On day 3, embryos from controls were in morula (65%) and early morula (17%) stages, while less than 2% of embryos from the gossypol-treated hamsters were in the morula stage. The numbers of embryo implantation sites on day 8 and pups in controls (14 +/- 2.0 and 12 +/- 1.5, respectively) were significantly higher than those in the gossypol-treated hamsters (8.5 +/- 2.0 and 4.0 +/- 1.5, respectively). Our results suggest that gossypol is able to affect fertilization, embryonic development, embryo implantation, and the number of pups in hamsters through a not-yet-defined mechanism.

Animals↗

PubMed1992

Role of cyclic adenosine monophosphate (cAMP) in vitro on bovine oocyte maturation.

This experiment attempted to determine the effect of cAMP on maturation of bovine oocytes in chemically-defined, serum-free medium. Cumulus-oocyte complexes were incubated in modified DME/Ham F-12 medium containing dbcAMP at 0 (control), 10(-6), 10(-4) and 10(-2) M. After 18 and 24 hours of culture, the percentage of oocyte maturation between 0 (control) and 10(-2) M dbcAMP-treated groups were significant. Some oocytes were cultured with dbcAMP (10(-2) M) for 6, 12 and 24 hours followed by incubation in control medium to test the reversibility of inhibition or of any harmful effect of dbcAMP. The inhibitory effect of 10(-2) M dbcAMP on bovine oocyte maturation was reversed by transferring cumulus-oocyte complexes to the control medium. In addition, forskolin (0.12 and 0.24 mM) was effective (P < 0.01) in preventing the resumption of meiosis. The cAMP content of oocytes cultured with forskolin was not increased, although cumulus cells responded to forskolin with an increase in cAMP content. These results indicate that elevated levels of cAMP in the culture medium are important in regulating resumption of meiosis of bovine oocytes in vitro.

Journal Article↗

PubMed1991

Fertilizability and subsequent developmental ability of bovine oocytes matured in medium containing epidermal growth factor (EGF).

We have previously shown that epidermal growth factor (EGF) is capable of promoting maturation of bovine cumulus-oocyte complexes in chemically defined serum-free medium. In this study, fertilizability and subsequent developmental capacity of bovine oocytes matured in EGF-containing medium were evaluated. Fetal bovine serum (FBS, 10%) and EGF at 10 ng/ml in Dulbecco's modified Eagles medium with Ham's nutrient mixture F-12 (DME/F12) significantly increased the rate of formation of two pronuclei compared with the rate obtained from DME-F12 alone (P<0.05). Early embryonic development was assessed during 48 h in culture. Data were evaluated in terms of cleavage and four- to eight-cell formation. Oocytes matured in 10 ng/ml EGF showed significantly higher rates of cleavage (P<0.01) and four- to eight-cell formation than did oocytes matured in control medium (P<0.05). Bovine oocytes matured in the presence of EGF can be normally fertilized and can cleave and develop in vitro up to the eight-cell stage.

Journal Article↗

PubMedDate not supplied

The importance of pulmonary function tests in adenotonsillectomy indications.

Children who had undergone adenotonsillectomy for recurrent adenotonsillitis showing no signs of clinical or radiological obstructive manifestations were evaluated with pulmonary function tests before, and one month after the operation. In relation to the result obtained by function tests, 60% of 45 cases (27) had the findings of mild obstructive pulmonary disease whereby these findings were in transient character that vanished after the operation. The following parameters were measured and found that they were all increased, mean FVC from 82.22 +/- 6.82 to 93.11 +/- 7.81 (p < 0.01), mean PEF from 77.60 +/- 8.38 to 88.60 +/- 5.57 (P < 0.01), mean FEVI from 74.28 +/- 11.68 to 90.15 +/- 7.28 (p < 0.01), mean FEF 25 from 71.44 +/- 11.53 to 83.53 +/- 6.40 (p < 0.01), mean FEF 50 from 69.53 +/- 14.53 to 84.37 +/- 7.72 (p < 0.01), mean FEF 75 from 70.08 +/- 12.15 to 85.48 +/- 7.15 (p < 0.01). In conclusion, pulmonary function tests could reveal the obstructive effects of adenotonsillar hypertrophy with no clinical or radiological obstructive findings, and could be useful in surgical indications of adenotonsillar hypertrophy dur to recurrent infections in children.

Adenoidectomy↗

PubMedDate not supplied

Sperm chromosomal abnormalities in patients with unexplained recurrent abortions.

Cytogenetic studies showed that about half of concepti were chromosomally abnormal in first trimester abortions. Sperm chromosomal abnormalities in men with normal karyotype could occur during spermatogenesis. The objective of this study was to evaluate sperm chromosomal abnormalities in patients with unexplained recurrent abortions. A total of 14 couples with normal karyotype, and negative workup for endocrine, immune and anatomical causes of recurrent abortion was investigated. Semen analysis was performed and chromosomal abnormalities were assessed by fluorescent in situ hybridization for chromosomes 13, 18, 21, X and Y. The average number of abortions was 5.8. The incidence of chromosomal abnormalities was 16.5% that was higher when compared to baseline (4.6%). In conclusion, a high rate of sperm chromosomal abnormalities was observed in recurrent abortion patients. These abnormalities might form during spermatogenesis since all patients had normal karyotype. Sperm chromosomal abnormality analysis can be included into recurrent abortion workup when no other cause is detected.

Abortion, Habitual↗