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Biomedical subjects

D Navot

Publications and source records attributed to D Navot.

105 records · Page 6Linked to original sources

Reduced fertilization ability of zona-free hamster ova by spermatozoa from male partners of normal infertile couples.

Zona-free hamster ova were used as a penetration test system for human semen obtained from male members of infertile couples. Forty semen samples from normal infertile couples were tested and compared with penetration rates obtained with control semen samples from fertile donors. Normal penetration rates ranged between 20-100%. Out of the 40 tested males, 11 were found to have penetration rates below 10%, two had between 11 and 19%, and in the remaining 27, the rate was above 20%. Three women, whose husbands were found to be in the first group (penetration rate below 10%), conceived after artificial donor insemination within three months of treatment. Thus, the use of the human-hamster ova penetration test should be used as an additional tool in diagnosis of infertility.

Adult↗

Timing of ovulation for AIH with freeze-thawed, subfertile sperm: two case studies.

Two couples were studied in whom the male partner had become sterile due to irradiation therapy given for advanced Hodgkin's disease. Both couples achieved conception during the first and second treatment cycle, respectively, despite obviously subfertile freeze-thawed sperm. The success is attributed to optimal timing of a single homo-insemination (AIH), which was made possible because we could detect ovulation by using currently available sophisticated methods. The importance of precise timing of ovulation for insemination and the ability to retain fertilizing capacity of young males with compromised sperm, who underwent sterilizing treatment, is discussed.

Adult↗

In vitro fertilization and embryo transfer--legal and religious aspects in Israel, patient selection, and a modified technique for oocyte collection.

In vitro fertilization (IVF) and embryo transfer (ET) have recently become an accepted treatment modality for patients with mechanically caused infertility. The first series admitted to our program comprised 42 patients with confirmed mechanical infertility. The method of patient selection and the techniques of laparoscopy, follicular aspiration and oocyte recovery are described. From 26 laparoscopies, a total of 39 oocytes was recovered. Normal cleavage of 10 oocytes was obtained; they were transferred into the uterus at the 4- to 16-cell stage. One pregnancy was obtained. An IVF and ET program involves certain ethical, legal and religious questions, which have special implications in Israel: foster mothers and the use of donor sperm are forbidden. Only married couples may enter the program. Indications, methods, success rates and method failure are discussed.

Embryo Transfer↗

The pattern of luteal phase plasma progesterone and estradiol in fertile cycles.

Serum levels of progesterone and estradiol at early, middle, and late luteal phases were compared in nonfertile cycles in which only ovulation occurred to those in cycles in which ovulation was verified by conception. Two groups of patients were studied: 33 normal ovulatory women (12 of whom conceived) and 28 women who underwent induction of ovulation (8 of whom conceived). In each group, mean midluteal levels of progesterone and estradiol were essentially similar in nonfertile and fertile cycles. In fertile cycles, the late luteal levels of both steroids were higher than their respective midluteal values, whereas the late luteal values dropped in the nonfertile cycles. The late luteal rise in estradiol was found to be a more sensitive indicator of pregnancy than that of progesterone. The progesterone/estradiol ratio was stable during the luteal phase of fertile and nonfertile cycles. The ratio in spontaneous cycles was 34.4 +/- 4.7 and only 17.9 +/- 4.3 in induced cycles. This marked decrease suggests an impairment of steroid metabolism in women who require induction of ovulation.

Adult↗

Effect of dexamethasone on amniotic fluid absorbance in Rh-sensitized pregnancy.

Five Rh-sensitized pregnant women between 23 and 30 weeks gestation, with a poor obstetric history and initially high delta A450 values, were treated with weekly doses of 24 mg of dexamethasone over a period of 2-7 weeks to enhance fetal lung maturation. Four women showed a gradual decline in delta A450 during the treatment. All five deliveries were delayed until fetal lung maturity was confirmed by amniotic fluid lecithin/sphingomyelin (L/S) ratio and all five fetuses survived. It is possible that high doses of dexamethasone delayed the anticipated intrauterine deterioration of the fetuses and may have prevented the need for intrauterine transfusions.

Absorption↗

Fetal response to voluntary maternal hyperventilation. A preliminary report.

Maternal hyperventilation can cause transient reduction in fetal oxygen tension. Fifty women with normal and high-risk pregnancies, between the 32nd and 43rd week, were voluntarily hyperventilated; in 33, fetal heart rate (FHR) acceleration or transient tachycardia were observed (reactive FHR). Of the 33 pregnancies the outcome was good in 30 (91%) as judged by the absence of perinatal death, no fetal distress in labor and no intrauterine growth retardation (IUGR). In 14 patients in whom there was no FHR response to maternal hyperventilation (non-reactive FHR), the outcome of pregnancy was significantly worse; one infant died neonatally, 10 were either chronically (IUGR), or acutely distressed. Only in 3 was the outcome good (21%). The study showed that there is good correlation between a "reactive" FHR and favorable neonatal outcome, and between a "non-reactive" FHR and an unfavorable neonatal outcome.

Apgar Score↗

Pregnancy in heterotopic fallopian tube and unilateral ovarian hyperstimulation.

A rare genital anomaly is described, consisting of a right hemiuterus with a rudimentary horn and a remotely located left fallopian tube, totally disconnected from the pelvic genitalia, and ruptured by an ectopic pregnancy. An associated finding was a unilateral hyperstimulated ovary (post HMG-HCG therapy), confined to an accessory ovary on the left. The case is presented in detail, and the unusual anatomical and functional features are discussed.

Abnormalities, Multiple↗

Asymmetry and discordance for congenital anomalies in conjoined twins: a report of six cases.

Six pairs of conjoined twins have been studied. The first case was a pair of 13-week-old omphalopagus fetuses. One was a holoacradius amorphus and the other had rachischisis and anencephaly. The second case was a pair of omphalopagus twins. One of the twins was macerated and corresponded to a developmental age of 13-14 weeks, while the other was developed to 28-30 weeks of gestation and exhibited urogenital and gastrointestinal defects not found in the smaller twin. In the third case, that of a thoracoomphalopagus, one had cleft lip and palate, pulmonic stenosis, and atresia of the ileocecal valve, while the other did not show these anomalies. In the fourth cae, also omphalopagus twins, one had a lumbosacral meningomyelocele and severe gastrointestinal and urogenital anomalies not found in the second twin. The fifth case was a pair of thoracoomphalopagus twins, sharing a common heart with asymmetrical anomalies. The sixth case was a diprosopus anencephalic conjoined twin. The first pairs of conjoined twins were discordant for several abnormalities in nonshared organs, in addition to having abnormalities of the conjoined organs. It seems that discordance in conjoined twins is not a rare finding. The factors that play a role in discordance of anomalies in conjoined twins are probably similar to the factors in monozygotic twins--i.e., environmental, genetic, and abnormal placental and/or fetal circulation.

Abnormalities, Multiple↗

Controlled ovarian hyperstimulation for the new reproductive technologies.

The aim of controlled ovarian hyperstimulation (COH) is to induce multiple morphologically and functionally adequate follicles with the aim of harvesting multiple fertilizable oocytes. We compared several treatment regimens with different FSH/LH ratios: group I was the basic 2 human menopausal gonadotropins (2hMG) protocol in which 2 ampules of hMG were administered starting on day 3 of the cycle; group II was the basic 2hMG in which 2 ampules of "pure" follicle stimulating hormone (p-FSH) were added on day 3 and 4; group III was the 2 FSH protocol in which 2 ampules of p-FSH were administered beginning on day 3; finally, group IV was the 4FSH: 4 ampules of p-FSH on day 3 and 4 followed by 2 ampules of p-FSH daily. The reference regimen was the 2hMG. Except for the higher rate of immature oocytes in 2FSH and 2hMG protocols, the number of preovulatory oocytes and fertilization rate were similar in all protocols. No differences occurred in the pregnancy outcome. The low dose Lupron (LDL) stimulation was an experimental protocol applied to two groups of women who had previously failed COH. Eight women who had a premature luteinization and 8 women who showed a low response agreed to participate in the protocol. Ten micrograms of the GnRH agonist leuprolide acetate (Lupron) were injected subcutaneously every 6 hours starting on cycle day 2 and menotropin stimulation was begun on day 3-5, according to individual patient response. The LDL protocol was successful in determining a favourable estradiol pattern and fertilizable oocytes.

Drug Administration Schedule↗