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Biomedical subjects

Z Ben-Rafael

Publications and source records attributed to Z Ben-Rafael.

At least 145 records · Page 8Linked to original sources
PubMed1995

Evaluation of serum-associated embryotoxicity in women with reproductive disorders.

PURPOSE: Our purpose was to determine whether some cases of infertility may be due to serological factors inhibiting development of the embryo. METHOD: We examined the effect of infertile women's sera on the expansion, attachment, and spreading of mouse blastocysts in culture. Cell marker expression was also assayed by an indirect immunofluorescence technique. Serum samples from 75 infertile women were compared to the effect of 24 control AB sera. RESULTS: After 72 hr, blastocyst spreading was significantly different depending on whether cultured in sera from women with unexplained infertility, anovulatory infertility, diethylstilbesterol exposure or controls. Neither sera from women with mechanical infertility (14) nor sera from women with endometriosis (8) affected blastocyst growth in culture. CONCLUSIONS: Inhibitory sera were capable of reducing cytokeratin expression but had no effect on placental alkaline phosphatase or concanavalin A expression by blastocyst cells. It can be inferred that the inhibitory effect of sera from women with certain types of infertility might be due to damage to the cytoskeleton. This in vitro assay may predict the success or failure of IVF.

Adult↗
PubMed1995

The role of the immune system in severe ovarian hyperstimulation syndrome.

The ovarian hyperstimulation syndrome is a serious, and potentially life-threatening, complication of ovulation induction. Hitherto, there has been no reliable test which will predict patients who will subsequently develop ovarian hyperstimulation syndrome. Recently, evidences have accumulated concerning the interaction between the immune and reproductive systems which results from sharing certain lymphohaematopoietic cytokines and their receptors. Furthermore, several cytokines have been implicated in the prediction and pathophysiology of ovarian hyperstimulation syndrome. If this is true, it may be possible to modify the patients' immunological homeostasis by passive immunization with intravenous immunoglobulin (IVIg) and thus to prevent ovarian hyperstimulation syndrome.

Albumins↗
PubMed1995

Contribution of class I HLA-A2 antigen in immune reactions.

The involvement of the Class I HLA-A2 antigen is briefly reviewed in relation to allograft rejection, the feto-maternal relationship, viral cytotoxic reactions and tumor immunity. It is suggested that the HLA-A2 molecule may have, as compared to other HLA Class I alleles, a dominant role as a restricting element in cytotoxic T-cell recognition in the feto-maternal relationship to male fetuses, in specific viral infections and in tumors. As compared to other HLA Class I alleles, its reduced expression or loss in a variety of tumors suggests its possible important role in tumor immune surveillance. The disappearance of HLA-A2 from tumor cells may eventually contribute to the escape from T-cell recognition of malignant cells.

Cytotoxicity, Immunologic↗
PubMed1995

Pharmacokinetics of follicle-stimulating hormone: clinical significance.

OBJECTIVE: To review studies that examine the pharmacokinetics and pharmacodynamics of endogenous, as well as several exogenous FSH preparations. DESIGN: Related studies were identified through a computerized bibliographic search. PATIENTS: Initial pharmacodynamic studies were done in animal models and in women and men with either hypogonadotropic hypogonadism or suppressed hypothalamic-pituitary-gonadal axis. More recent studies evaluated FSH pharmacokinetics during ovulation induction treatment in women with normal ovulatory cycles or polycystic ovarian syndrome. RESULTS: Various types of FSH exist according to their sialic acid content. High estrogen levels induce the secretion of less sialylated molecules with higher receptor affinity and an increased clearance rate. It appears that there is a threshold FSH level that should be reached to achieve an ovarian response. A very narrow range exists between the threshold and ceiling level for monofollicular growth. This threshold level is surpassed intentionally during IVF treatment cycles to induce multiple follicular recruitment. The threshold level can change under situations such as polycystic ovaries, perimenopause, oral contraceptives, and GnRH analogue treatment. CONCLUSIONS: To avoid the risk of ovarian hyperstimulation syndrome and multiple pregnancies, careful adjustments of serum FSH levels should be made by fine dosage modifications. By monitoring FSH levels and using less sialylated preparations, the efficacy of the treatment probably will improve.

Animals↗
PubMed1995

A comparative prospective study of conventional regimen with chronic low-dose administration of follicle-stimulating hormone for anovulation associated with polycystic ovary syndrome.

OBJECTIVE: To compare efficiency of conventional and chronic low-dose regimens for treatment of anovulation associated with polycystic ovary syndrome (PCOS). DESIGN: Fifty participants divided into two equal groups. The first group was treated with urinary human FSH using a conventional stepwise protocol and the second group was treated with a regimen of chronic low-dose and small incremental rises with urinary human FSH or with recombinant human FSH for a maximum of three cycles. SETTING: Tertiary referral university hospital fertility unit. PATIENTS: Fifty infertile women with clomiphene citrate-resistant anovulation associated with PCOS. MAIN OUTCOME MEASURES: Pattern of follicular development, amount of FSH required, serum E2 concentrations, cycle fecundity, cumulative conception, and live birth rates. Multiple pregnancy and ovarian hyperstimulation syndrome (OHSS) rates. RESULTS: Compared with the conventional dose protocol, the chronic low-dose regimen yielded slightly improved pregnancy rates (40% versus 24%) while completely avoiding OHSS and multiple pregnancies, which were prevalent (11% and 33%, respectively) with conventional therapy. Monofollicular development was induced in 74% versus 27% of cycles, and the total number of follicles > 16 mm and E2 concentrations were half those observed on conventional therapy. CONCLUSIONS: For women with PCOS, a chronic low-dose regimen of FSH eliminated complications of OHSS and multiple pregnancies while maintaining a satisfactory pregnancy rate. This modality, thus, has distinct advantages and could well replace conventional gonadotropin therapy for these patients.

Adult↗
PubMed1995

Hyperprolactinemia after treatment of long-acting gonadotropin-releasing hormone analogue Decapeptyl in girls with central precocious puberty.

OBJECTIVE: To clarify the effects of prolonged treatment with long-acting GnRH analogue on serum PRL levels. DESIGN: Blood PRL levels were measured at 9 A.M. every 28 days for a period of 6 months. SETTING: Pediatric Endocrine Clinic, Hasharon Hospital, Petah Tiqva, Israel. PATIENTS: Thirteen girls with idiopathic central precocious puberty. RESULTS: Hyperprolactinemia developed in 5 of 13 girls after treatment with long-acting GnRH-a; mean blood PRL in all 13 girls rose significantly from 11.9 +/- 5.6 to 21.5 +/- 12.5 micrograms/L (mean +/- SD). CONCLUSIONS: The mechanism of hyperprolactinemia in our patients is unclear. It may have resulted from a decline in the release of the hypothalamic PRL inhibitory factor. Clinically, transient hyperprolactinemia during long-acting GnRH-a treatment for central precocious puberty also may reflect a constant depression of LH secretion.

Female↗
PubMed1995

A severe case of ovarian hyperstimulation syndrome despite the prophylactic administration of intravenous albumin.

OBJECTIVE: To evaluate the role of the recently suggested IV administration of human albumin solution as an effective preventive measure of severe ovarian hyperstimulation in high-risk patients. CASE: Presented here is, to the best of our knowledge, the first case of early severe ovarian hyperstimulation necessitating early transabdominal aspiration of ascites and intensive fluid and colloid (dextran and albumin) replacement, which developed despite administration of IV human albumin solution in an attempt to prevent severe ovarian hyperstimulation. CONCLUSIONS: Because IV albumin does not prevent severe ovarian hyperstimulation in absolute terms, its use in high-risk patients should not lead one astray. Further research should be directed at investigating the fundamental cause of ovarian hyperstimulation syndrome and developing a reliable predictive test for this complication.

Adult↗
PubMed1995

Interleukin-2 and ovarian hyperstimulation syndrome: a pilot study.

A prospective case-controlled study was conducted to evaluate the association between the concentrations of interleukin-2 (IL-2) in human follicular fluid obtained at the time of oocyte collection for in-vitro fertilization (IVF) and the development of ovarian hyperstimulation syndrome (OHSS). Follicular fluid was obtained at the time of oocyte collection for IVF consecutively from 40 patients at risk of developing OHSS. Among the 40 patients participating in the study, seven subsequently developed OHSS. Their follicular fluid samples, together with those of an additional seven patients matched by age who did not develop OHSS, were tested for osmolality, total protein content and IL-2 concentrations, and mean serum oestradiol concentrations at the time of human chorionic gonadotrophin (HCG) administration and the mean number of aspirated oocytes were also measured. Follicular fluid IL-2 concentrations were significantly higher (P < 0.002) in the OHSS group as compared to the control group. No significant differences were found between the two groups regarding the mean serum oestradiol concentration on the day of HCG administration, or the mean number of aspirated oocytes, follicular fluid osmolality, or total protein concentrations. This study suggests an association between follicular fluid IL-2 concentration and OHSS. IL-2 is known to cause 'vascular leak syndrome', which resembles OHSS. These observations, together with the established interaction between the immune and the reproductive systems, may suggest a pivotal role of IL-2 in the pathogenesis of OHSS.

Case-Control Studies↗
PubMed1995

Adjuvant growth hormone for induction of ovulation with gonadotrophin-releasing hormone agonist and gonadotrophins in polycystic ovary syndrome: a randomized, double-blind, placebo controlled trial.

The objective of this study was to explore the effect of cotreatment with recombinant human growth hormone (GH), gonadotrophin-releasing hormone agonist (GnRHa) and human menopausal gonadotrophin (HMG) for induction of ovulation in women with clomiphene resistant polycystic ovary syndrome (PCOS). It was designed as a randomized, double-blind, placebo controlled trial in which 30 women with anovulation associated with PCOS who were resistant to clomiphene all received DTRP6-LHRH (Decapeptyl microcapsules, 3.75 mg, i.m.) and, 2 weeks later, HMG in a standard, conventional, individually adjusted dose regimen until human chorionic gonadotrophin (HCG) and then luteal phase support could be given. From day 1 of HMG therapy, patients were randomized to receive either human GH (Norditropin, 12 IU/day, i.m., for 7 days) or placebo. The number of ampoules, duration of treatment and daily effective dose of HMG required to achieve ovulation, serum oestradiol concentrations and number of follicles induced, ovulation and pregnancy rates, serum insulin and insulin-like growth factor-I (IGF-I) concentrations were measured. There were no significant differences between growth hormone and placebo groups in any of the outcomes measured, other than a growth hormone induced increase in serum insulin and IGF-I levels. We conclude that although GH kinetics are abnormal and GH pituitary reserves generally low in women with PCOS, adjuvant GH treatment to GnRHa/HMG does not influence follicular development or sensitivity in response to gonadotrophins and that it does not seem likely to be of any potential clinical benefit for the treatment of PCOS.

Adult↗
PubMed1995

A reappraisal of the feedback effects of oestradiol upon luteinizing hormone surge.

The objective of this study was to assess the temporal relationships of serum oestradiol and luteinizing hormone (LH) with regard to the feedback mechanism leading to the LH surge. Daily measurements of oestradiol, LH and follicle stimulating hormone were made in 65 women with ovarian failure undergoing an evaluation of endometrial response to oral cycle stimulation. Patients received incremental oral oestradiol valerate for varying durations at the in-vitro fertilization unit of the Sheba Medical Center, Tel Hashomer, Israel. The treatment protocol involved the administration of daily oestradiol valerate, starting with 1 mg/day, followed by a daily increment of 1 mg for a total of 4, 6 and 8 days. After the last day, a daily maintenance dose of 2 mg was continued. Serum oestradiol concentrations correlated with the dose of oral oestradiol valerate. Peak oestradiol concentrations (mean +/- SEM) were 572 +/- 60, 721 +/- 42 and 797 +/- 53 pg/ml for 4, 6 and 8 days of oestradiol valerate administration respectively. Serum LH, after an initial suppression, peaked 2 days after maximal oestradiol valerate dose and 1 day after peak serum oestradiol. The magnitude of the LH peak was proportional to the duration of incremental oestradiol valerate treatment. In conclusion, the LH surge is temporally related to the cessation of serum oestradiol increase. Consequently, the occurrence of this surge can be explained by a simple negative feedback inhibition of pituitary LH release rather than by a dual negative/positive mechanism.

Adult↗
PubMed1995

Laparoscopic removal of an abdominal pregnancy adherent to the appendix after ovulation induction with human menopausal gonadotrophin.

The laparoscopic management of tubal pregnancies has become a standard form of treatment. We present, for the first time, a successful laparoscopic approach in the management of early abdominal pregnancy. Although it is difficult to reach conclusions from such limited published experience, it nevertheless appears that early abdominal pregnancies can be treated via operative laparoscopy. The possible advantages of such a therapeutic approach include lower morbidity and mortality, and a better fertility prognosis.

Adult↗