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Biomedical subjects

Y Tadir

Publications and source records attributed to Y Tadir.

103 records · Page 6Linked to original sources
PubMed1986

Actual effective CO2 laser power on tissue in endoscopic surgery.

To elucidate the cause of power reduction in endoscopic carbon dioxide (CO2) laser surgery and to define the actual effective power on tissue of a beam delivered through different endoscopes, we designed an experimental model. In passing a CO2 laser beam through a CO2 gas-pressurized chamber, no significant power loss was noted. A correlation between the internal diameter of an endoscope and the power output became evident. Effective power of 92%, 85%, and 48% of the potential 100% was measured when a beam was delivered through single- and double-puncture laparoscopes and a hysteroscope, respectively. These figures are relevant in predicting CO2 laser effect used endoscopically.

Atmospheric Pressure↗
PubMed1984

Hysteroscope for CO2 laser application.

Endoscopic laser surgery is becoming more common with the development of suitable instruments. A hysteroscope designed for use with a Sharplan CO2 laser is described in detail. The method of application, results of preliminary experience, and possible indications are discussed.

Endoscopes↗
PubMed1984

New instrumentation and technique for laparoscopic carbon dioxide laser operations: a preliminary report.

Laparoscopic surgery, the accepted procedure for several indications, still has some limitations, mainly due to the risk of uncontrollable bleeding and damage to the surrounding tissues that may result from the procedure. With the advent of the surgical carbon dioxide laser apparatus and its advantage in producing a bloodless incision, the authors have modified their approach toward laparoscopic surgery. A variety of special straight laser channels for introduction into the abdominal cavity have been developed; use of these channels requires special care to protect surrounding tissues from damage during the procedure. A Sharplan laser delivery system comprising an articulated arm was used, and the operative area visualized and controlled by single- and double-puncture laparoscope systems. The techniques were first applied in rabbits and, after several improvements, used in humans for various indications. The laser laparoscope can be particularly useful in the treatment of endometriosis and lysis of pelvic adhesions.

Carbon Dioxide↗
PubMed1981

[Gonadotrophin therapy (author's transl)].

Strict selection of patients is of paramount importance with a view to obtaining optimum results in the treatment of infertile men with gonadotrophins (HMG/HCG). The use of algorithmic tables permits the exclusion of cases of primary orchiopathy, or of genetic or other causes of infertility independent of the endocrine system. Within the scope of a retrospective study this paper gives an account of the results obtained with gonadotrophin therapy in 25 men presenting severe oligozoospermia. The patients had been selected according to the above-mentioned algorithmic schedule, and their serum levels of FSH, LH and testosterone were determined before and after GNRH stimulation. The present study establishes criteria for the selection of such patients as can be treated successfully with gonadotrophin.

Chorionic Gonadotropin↗
PubMedDate not supplied

Treatment of male infertility with human gonadotrophins: selection of cases, management and results.

To obtain optimal results with gonadotrophic therapy (HMG/hCG) in infertile males, strict selection of patients is of paramount importance. The use of algorithmic schemes permits the exclusion of patients with primary testicular failure, genetic and non-endocrine causes of infertility. This paper describes a retrospective study on the results of gonadotrophic therapy in 25 severe oligozoospermic males, preselected according to the above scheme and in whom levels of FSH, LH and Testosterone before and during GnRH stimulation were assessed. This study indicates that low basal levels of FSH, concomitant with low or lack of FSH response to GnRH stimulation may be useful in selection of patients with a fair chance of success for gonadotrophic therapy.

Chorionic Gonadotropin↗
PubMedDate not supplied

Comparison of pituitary response to regular GnRH, analogue (D-TRP6) and placebo.

Pituitary response to synthetic regular GnRH, to a potent analogue (D-TRp6) and to placebo were compared in ten azoospermic males. FSH and LH were measured prior to and at given intervals following administration of each substance. In addition, plasma levels of testosterone and prolactin were measured. There was no significant difference in the magnitude of FSH and LH release following injection of their the regular or the analogue form of GnRH. However, plasma gonadotrophins remained elevated for significantly longer time periods following the administration of the analogue GnRH. In those patients in whom LH levels remained elevated for at least 24 hours the observation of elevated testosterone levels permitted the inference of adequate biological activity of endogenously produced LH. Patients who did not respond to the regular GnRH were also non-responsive to D-TRp6 GnRH. A surprising finding ws elevated prolactin levels 4-6 hours following GnRH administration. Placebo had no influence on gonadotrophins, testosterone and prolactin.

Follicle Stimulating Hormone↗
PubMedDate not supplied

A high proportion of double-headed and double-tailed sperm in semen of a human male. A case report.

We present the case of a patient whose semen contained 30% of sperm with double heads and double tails at various stages of attachment due to abnormal meiosis. The genital system, sperm density, endocrinological profile and karyotype were normal. It is postulated that abundance of the above-noted type of sperm pathology in the human semen might not necessarily be associated with oligozoospermia or fertility impairment.

Adult↗
PubMedDate not supplied

Immunosuppressive activity in culture media containing human oocytes fertilized in vitro.

A possible cause for implantation failure following embryo transfer is the rejection of pre-embryos by the maternal immune system. To elucidate the mechanisms underlying the rescue of the pre-embryo from maternal rejection, immunosuppressive activity was investigated in culture media containing human oocytes fertilized in vitro by employing the graft-versus-host reaction and the active rosette test. Normal donor lymphocytes were incubated with culture medium containing either fertilized or nonfertilized oocytes. Control experiments were carried out using lymphocytes incubated in culture medium only, as well as in culture medium containing human sperm. In 67% of the tests (12 out of 18), graft-versus-host reaction was inhibited, as compared to 29% of those performed with medium in which oocytes failed to fertilize (p less than .03), and 33% with medium in which only sperm was present. The frequency of an inhibitory active rosette test was similar in both groups. It is possible that immunosuppressive properties are acquired by the human pre-embryo as it grows in culture. Detection of such substances, which could contribute to the establishment of pregnancy, may improve monitoring of embryo quality prior to transfer.

Culture Media↗
PubMedDate not supplied

Effect of pentoxifylline on the intrinsic swimming forces of human sperm assessed by optical tweezers.

It is still controversial whether in vitro exposure of sperm to pentoxifylline increases sperm motility and force, which is defined as the product of velocity by beat frequency of the tail. Laser optical tweezers have been successfully used in the past to evaluate sperm force in basal conditions. The aim of this prospective study was to determine whether exposure of human sperm to pentoxifylline has any effect on sperm intrinsic forces. Twelve healthy subjects undergoing routine semen analysis were enrolled in the study. Ten exhibited normal semen parameters, 2 exhibited asthenozoospermia. Each semen specimen was washed and, after swim-up, resuspended in human tubal fluid (HTF) and divided into 2 aliquots. One aliquot was incubated with pentoxifylline for 30 minutes (final concentration = 3.6 mM); the second aliquot, without pentoxifylline, served as a control. After 30 minutes the pentoxifylline-treated aliquot was divided into 2 portions, 1 of which was washed to remove the pentoxifylline, the other was left in prolonged coincubation with the chemical. The main outcome was the measurement of sperm intrinsic force in milliwatts (mW), which was assessed by means of a noninvasive infrared laser optical trap created by a continuous wave, 1064-nm Nd:YAG laser beam directed in an inverted microscope. Exposure of sperm to pentoxifylline consistently increased sperm relative escape force from the laser optical trap. The increase ranged from 33% to 154% over baseline force compared with controls. The average absolute increase in sperm force rose from 37 mW to 79 mW (P < .05). Specimens with sperm having an initial low relative escape force gained the highest relative increase. The effect of pentoxifylline on sperm force, already apparent after 5 minutes, reached a peak at 30 minutes and persisted for up to 3 hours in sperm that were left in coincubation and in those on which the pentoxifylline had been washed off. In conclusion, pentoxifylline significantly increases sperm intrinsic relative force in normozoospermic and asthenozoospermic samples. This experiment confirms that optical tweezers can provide an accurate determination of sperm force in in vitro conditions. Clinical data must now establish whether a documented increase in sperm force is an important parameter for assessing sperm fertilizing capacity.

Humans↗
PubMedDate not supplied

Comparison of different follicle-stimulating hormone and luteinizing hormone ratios for ovulation induction during in vitro fertilization.

Five normally menstruating women were treated in an attempt to induce development of multiple follicles. They were randomly divided into two groups. The first group, consisting of three women, was treated with a combination of follicle stimulating hormone (FSH) and human menopausal gonadotropin (hMG) (combination FSH/hMG). The second group, two women, was treated with hMG only. Following a nonconceptual cycle, the treatments were exchanged. The increment patterns of serum estradiol during the follicular phase and progesterone levels in both groups were identical. Ultrasonographic scanning revealed similar number and size of the growing follicles, which subsequently terminated in the same oocyte recovery rate in both groups (7.6 +/- 3.4 oocytes/procedure in the combination FSH/hMG and 8.0 +/- 2.5 in the hMG-only group). Fertilization and cleavage rates were also similar. These data indicate that high FSH/LH levels in different ratios do not alter ovarian response and oocyte fertilization potential.

Adult↗
PubMedDate not supplied

Changes in menstrual blood loss and libido after different methods of tubal ligation.

A study was carried out to investigate the menstrual blood loss and changes in sexual life following two methods of tubal sterilization, the Pomeroy procedure and fimbriectomy, as compared with a control group having undergone Cesarean section alone. Results support the approach that hysterectomy be performed in older women, over the age of 40, and fimbriectomy in younger patients, in whom further pregnancy or reanastomosis of the Fallopian tube is absolutely contraindicated.

Adult↗
PubMedDate not supplied

Neonatal assessment of babies conceived by in vitro fertilization.

PROBLEM: Neonatal outcome of in vitro fertilization (IVF) pregnancies has been described by different authors, but several issues have yet to be resolved. The aim of the present study was to evaluate neonates conceived in vitro and to direct special attention to neonatal morbidity and prevalence of minor abnormalities. The information that has been accumulated so far is scant. METHOD: The first 100 babies conceived in vitro, and subsequently born in our institute, were investigated and compared with the general, spontaneously conceived newborn population. All infants were examined by a senior neonatologist, and the data that were recorded included gestational age at delivery, birth weight, gender, major malformations, minor congenital abnormalities, neonatal mortality, and neonatal morbidity (including asphyxia, jaundice, meconium aspiration, hypoglycemia, and hypocalcemia). RESULTS AND CONCLUSIONS: The data indicate that the IVF neonates assessed had a higher rate of low birth weight (37%), twinning (30%), and preterm birth (20%) in comparison with the general reference population (p < 0.05). However, no differences were encountered either in the rate of small for gestational age infants or the incidence of major malformations and minor abnormalities between these groups of newborns. The overall neonatal morbidity in IVF babies was found to exceed that of the general population. Nevertheless, at birth, there were no clinical pathognomonic signs typical of IVF babies, although more detailed metabolic, endocrine, and neurobehavioral studies are still required to confirm that newborns conceived in vitro do not differ from those conceived spontaneously in any of these respects.

Female↗