Search PubMed⌕ Search

Biomedical subjects

I Tur-Kaspa

Publications and source records attributed to I Tur-Kaspa.

At least 19 recordsLinked to original sources
PubMed2005

Preimplantation diagnosis and HLA typing for haemoglobin disorders.

Haemoglobin disorders are among the most frequent indications for preimplantation genetic diagnosis (PGD), introduced as an important option to couples at risk for producing offspring with thalassaemia and sickle cell disease. Previous experience mainly included PGD for beta-thalassaemia, while PGD for alpha-thalassaemia resulting in an unaffected pregnancy has not been reported. This study presents the results of the world's largest experience of 197 PGD cycles for haemoglobin disorders, which includes PGD for alpha-thalassaemia, resulting in 53 clinical pregnancies and birth of 45 healthy children, with five still ongoing. Fifty-four of these cycles were performed in combination with HLA typing, allowing the birth of thalassaemia-free children who were also HLA identical to the affected sibling, with successful stem cell transplantation in one case. As an increasing proportion of patients requesting PGD with HLA typing are of advanced reproductive age, aneuploidy testing was performed simultaneously with PGD. The results show that PGD has now become a practical approach for prevention of haemoglobin disorders, and is gradually being used also for improving access to HLA compatible stem cell transplantation for this group of diseases.

Aneuploidy↗
PubMed2005

Preimplantation testing for chromosomal disorders improves reproductive outcome of poor-prognosis patients.

The clinical impact of PGD was evaluated through the analysis of the reproductive outcome before and after PGD in the same group of poor prognosis IVF patients, undergoing PGD for chromosomal abnormalities. Based on a series of 2359 PGD cycles, resulting in the establishment of 498 chromosomal abnormality-free clinical pregnancies, the reproductive history prior to PGD was analysed. Of 483 previous pregnancies analysed in patients with 432 pregnancies generated after PGD for aneuploidies, 328 (68%) ended in spontaneous abortions, in contrast to 28.4% after PGD, with only 155 (32%) resulting in deliveries, compared with 71.9% take-home baby rates after PGD. The patients experienced 315 previous IVF attempts, resulting in the transfer of 706 embryos in 308 cycles, of which only 49 (6.9%) implanted, compared with a 34.9% implantation rate observed in the same patients after PGD. Similar analysis of the previous reproductive outcomes of 45 carriers of balanced translocations achieving pregnancies following PGD, showed even stronger clinical impact, with a reduction of spontaneous abortions from 87.8% to 17.8%, and improvement of take-home baby rate from 11.5% to 81.4% after PGD. The results demonstrate a strong clinical impact of PGD, resulting in improvement of implantation rate, reduction of spontaneous abortions and increase in the take-home baby rate.

Abortion, Spontaneous↗
PubMed2000

Reducing the risk of high-order multiple pregnancy after ovarian stimulation with gonadotropins.

BACKGROUND: The incidence of multiple gestation after therapy for infertility is especially high among women in whom ovulation is induced with gonadotropins. Whether the number of high-order multiple pregnancies (those with three or more fetuses) can be reduced is not known. METHODS: We analyzed data on 3347 consecutive treatment cycles in 1494 infertile women, 441 of which resulted in pregnancy. The data collected included the peak serum estradiol concentration, the number of follicles 16 mm or larger in diameter, and the total number of follicles on the day of induction of ovulation with human chorionic gonadotropin. Receiver-operating-characteristic curves and ordinal logistic-regression analyses were used to identify values that predicted multiple conceptions. RESULTS: Among the 441 pregnancies, 314 resulted from the conception of singletons, 88 of twins, 22 of triplets, 10 of quadruplets, 5 of quintuplets, and 2 of sextuplets. Neither the number of follicles 16 mm or larger nor peak serum estradiol concentrations greater than 2000 or 2500 pg per milliliter (7342 or 9178 pmol per liter) (the cutoff values currently in wide use) were significantly associated with the incidence of high-order multiple pregnancy. However, increasing total numbers of follicles and increasing peak serum estradiol concentrations correlated significantly with an increasing risk of high-order multiple pregnancy (P<0.001), as did younger age (P=0.008). The risk of high-order multiple pregnancy was significantly increased in women with a peak serum estradiol concentration of 1385 pg per milliliter (5084 pmol per liter) or higher (multivariate odds ratio, 1.9; 95 percent confidence interval, 1.3 to 2.8) or with seven or more follicles (multivariate odds ratio, 2.1; 95 percent confidence interval, 1.2 to 3.9) on the day of induction of ovulation. CONCLUSIONS: Gonadotropin stimulation that is less intensive than is currently customary may reduce the incidence of high-order multiple pregnancy in infertile women, though only to a limited extent and at the expense of overall pregnancy rates.

Adult↗
PubMed2000

A transcription-activating polymorphism in the ACHE promoter associated with acute sensitivity to anti-acetylcholinesterases.

Hypersensitivity to acetylcholinesterase inhibitors (anti-AChEs) causes severe nervous system symptoms under low dose exposure. In search of direct genetic origin(s) for this sensitivity, we studied six regions in the extended 22 kb promoter of the ACHE gene in individuals who presented adverse responses to anti-AChEs and in randomly chosen controls. Two contiguous mutations, a T-->A substitution, disrupting a putative glucocorticoid response element, and a 4-bp deletion, abolishing one of two adjacent HNF3 binding sites, were identified 17 kb upstream of the transcription start site. Allele frequencies for these mutations were 0.006 and 0.012, respectively, in 333 individuals of various ethnic origins, with a strong linkage between the deletion and the biochemically neutral H322N mutation in the coding region of ACHE. Heterozygous carriers of the deletion included a proband who presented with acute hypersensitivity to the anti-AChE pyridostigmine and another with unexplained excessive vomiting during a fourth pregnancy following three spontaneous abortions. Electromobility shift assays, transfection studies and measurements of AChE levels in immortalized lymphocytes as well as in peripheral blood from both carriers and non-carriers, revealed functional relevance for this mutation both in vitro and in vivo and showed it to increase AChE expression, probably by alleviating competition between the two hepatocyte nuclear factor 3 binding sites. Moreover, AChE-overexpressing transgenic mice, unlike normal FVB/N mice, displayed anti-AChE hypersensitivity and failed to transcriptionally induce AChE production following exposure to anti-AChEs. Our findings point to promoter polymorphism(s) in the ACHE gene as the dominant susceptibility factor(s) for adverse responses to exposure or to treatment with anti-AChEs.

Acetylcholinesterase↗
PubMed2000

Thyroid hormone levels in cord blood of infants with acidemia at birth.

OBJECTIVE: To study the funic thyroid hormone levels in cases were fetal distress during labor resulted in acidemia at birth. MATERIAL AND METHODS: Arterial and venous levels of TSH, total T4, free T4 and total T3 obtained from cord blood at birth of twelve acidemic fetuses were compared with normal controls. RESULTS: Acidemic fetuses had a significanly higher TSH levels than controls (16.5+/-2. 1 microI/dl vs. 9.6+/-1.4 microI/dl, P=0.01). Total T3 levels were significantly lower in acidemic fetuses (49.2+/-2.9 ng/dl vs. 63+/-5. 5 ng/dl, P=0.04). Total and free T4 levels were similar and there was no difference between arterial and venous levels of the hormones. CONCLUSIONS: Birth acidemia from fetal distress during labor is associated with higher TSH levels and lower T3 levels.

Acidosis↗
PubMed1999

Do human eggs attract spermatozoa?

A key process in human fertilization is bringing the two gametes together, so that the complex molecular events involved in sperm and egg interaction can begin. Does nature allow fertilization to occur only as a consequence of a chance collision, or is there a precontact sperm-egg communication? This review summarizes the bioassays used in testing human spermatozoa for chemotaxis, emphasizing the necessity to distinguish between chemotaxis and other accumulation-causing processes, and the results obtained. It demonstrates that human sperm chemotaxis to a follicular factor(s) does occur, at least in vitro, and that only capacitated spermatozoa are chemotactically responsive. Substances that have been proposed as attractants for human spermatozoa are reassessed. The potential role of sperm chemotaxis in vivo is discussed. Faulty precontact sperm-egg communication may be one of the causes of male infertility, female infertility, or both. On the other hand, interfering with human sperm chemotaxis may represent an exciting new approach to contraception.

Animals↗
PubMed1999

Distribution of serum creatine kinase activity in young healthy persons.

The normal distribution of serum creatine kinase (CK) was determined in 428 men (mean age = 21.5) and 540 women (mean age = 20.2). The bootstrap method was employed to obtain statistical parameters of CK reference range and correlations with physical activity habits, BMI, cigarette smoking and alcohol consumption. CK distribution was non-Gaussian and skewed toward the higher values; 18.9% of the men and 4.6% of the women had values above the upper reference limits defined for the commercial assay kit. The median 97.5 percentile value was 532 u/l for men and 248 u/l for women (95% confidence interval of 384-738 u/l and 184-340 u/l, respectively). A significant correlation was found only between CK and alcohol consumption in men. Myoglobin level in a representative group of subjects correlated well with CK activity for both genders. Our findings define the range of CK values in a healthy, young, heterogeneous population. We suggest that only CK levels above the determined 97.5 percentile should warrant further clinical investigation.

Adult↗
PubMed1999

Viagra for temporary erectile dysfunction during treatments with assisted reproductive technologies.

During treatments with assisted reproductive technologies (ART), some men may have difficulties in producing spermatozoa on demand at the time of insemination, either for intrauterine insemination (IUI) or for in-vitro fertilization (IVF). This situation imposes tremendous stress on the couple and may cause cancellation of the treatment. Here we describe, for the first time, the use of sildenafil citrate (ViagraTM) for temporary erectile dysfunction in couples undergoing ART. The first case was a man who could not produce spermatozoa for the first IVF treatment after an exhausting trial for 12 h, despite the fact that he never had problems in providing sperm samples during previous IUI cycles. Using Viagra enabled him to provide spermatozoa, but the delay in oocyte insemination resulted in no embryonic development. This prompted us to be more alert to this option and to suggest the use of Viagra to men who had a history of erectile dysfunction during previous ART cycles. In these cases, the use of Viagra was planned in advance and it successfully solved any unpredictable erectile dysfunction on the day of insemination. Such cases emphasize the need to think in advance of this potential use of Viagra during ART.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1999

Detection of partial and complete acrosome reaction in human spermatozoa: which inducers and probes to use?

The acrosome reaction (AR), an essential step for achieving mammalian fertilization, was recently introduced as a means of clinical evaluation of male fertility. However, most of the available techniques for acrosomal status assessment (except those employing electron microscopy) do not define whether the measurements represent partial or complete AR. We, therefore, performed a crossover investigation of the types of inducers and probes required for detecting partial or complete AR in human spermatozoa. The acrosomal status before and after stimulation with four AR inducers was evaluated after incubation for 3 h in capacitating conditions. We used a fluorescence-activated cell sorter with fluorescein isothiocyanate-conjugated monoclonal antibody CD46 (FITC-CD46) targeting the inner acrosomal membrane for detecting a complete AR, and fluorescein isothiocyanate-Pisum sativum agglutinin (FITC-PSA) targeting the acrosomal content for detection of both partial and complete AR. Without stimulation or following stimulation with progesterone, follicular fluid (FF) or phorbol myristate ester (PMA), the AR could be detected with FITC-PSA but not with FITC-CD46. Following stimulation with the calcium ionophore A23187, the AR could be detected by both FITC-PSA and FITC-CD46. These results suggest that spontaneous AR as well as AR induced by progesterone, PMA and FF are partial. In contrast, the AR induced by A23187 is total, i.e. both partial and complete. These findings are valuable for both research and clinical purposes and are a step towards an international agreement on a standard test for human sperm AR, for which there is an urgent need.

Acrosome Reaction↗
PubMed1999

Human sperm chemotaxis: is progesterone a chemoattractant?

Follicular fluid (FF) induces sperm chemotaxis in human spermatozoa. Progesterone also causes sperm accumulation. However, sperm accumulation can be caused by chemotaxis, chemokinesis, and trapping of various kinds. It has been suggested that progesterone also induces chemotaxis in human spermatozoa. In view of the physiological significance of sperm chemotaxis in human fertilization and its potential clinical implications, it is important to determine unequivocally whether chemotaxis is induced by progesterone and, if so, whether progesterone in FF is the chemoattractant. To resolve these questions we looked for characteristic changes in the direction of sperm swimming toward pure progesterone as well as toward FF before and after progesterone removal. Progesterone caused sperm accumulation and hyperactivation-like motility, but it caused very few changes in the direction of sperm swimming that are characteristic of chemotaxis. Removal of progesterone (and other steroids) from FF by charcoal treatment abolished the sperm hyperactivation-like motility but not sperm chemotaxis. These results suggest that while progesterone might be a weak chemoattractant, it is not the major chemoattractant in FF. Progesterone probably causes human sperm accumulation mainly by inducing hyperactivation-like motility and, as a consequence, sperm trapping.

Chemotaxis↗
PubMed1999

Preparing hospitals for toxicological mass casualties events.

OBJECTIVE: For most hospital staffs, treatment of chemical casualties presents an obscure and even frightening situation. We report our unique experience from hospital drills in order to improve hospital preparedness for patient management under mass casualty conditions involving hazardous chemicals. SETTING: Twenty-one major hospitals in Israel. INTERVENTIONS: A unique hospital deployment plan for the management of chemical casualties was developed, and hospitals were required to have a full chemical practice drill every 3 to 5 yrs. These drills were designed as realistically as possible, and all included the use of personal protective equipment, decontamination, and treatment of simulated patients. Twenty-five percent of these patients, simulating children and adults, required intensive care and ventilation support. Hospitals were inspected and reviewed on the quality of treatment given and the overall continuity of care as well as on their administrative performance. RESULTS: Between 1986 to 1994, 30 full chemical practice drills were conducted in 21 major hospitals. Each drill included treatment of 100 to 400 simulated patients. The lessons from the hospital drills are described and were incorporated in the proposed revised hospital deployment plan. All hospitals significantly improved their ability to respond appropriately to these incidents. CONCLUSIONS: The level of preparedness for a chemical mass casualty scenario should be established according to the existing threat and the available resources. The proposed plan can serve as a basis for hospital planning and staff training worldwide, thus facilitating optimal care in the event of an incident involving toxic chemicals. A cost-effective scale for hospital preparation levels according to the existing threat is suggested.

Adult↗
PubMed1998

Sperm capacitation is, after all, a prerequisite for both partial and complete acrosome reaction.

The acrosome reaction (AR) - an essential step in mammalian fertilization - can occur, according to the consensus, only in capacitated spermatozoa. In apparent contrast, recent reports have demonstrated that human spermatozoa incubated in vitro in an albumin-free medium and therefore believed to be non-capacitated, do undergo the AR. With the aim of determining unequivocally whether or not capacitation is required for the AR and whether albumin is essential for capacitation, we compared the potential to undergo partial and complete AR (induced by phorbol myristate ester or by the Ca2+ ionophore A23187) between human spermatozoa incubated in a capacitating medium, albumin-free medium, and non-capacitating medium. The results clearly demonstrate that capacitation is, after all, a prerequisite for both partial and complete AR. Albumin, on the other hand, is essential only for acquiring the capacity to undergo complete, not partial AR.

Acrosome↗
PubMed1998

Cortisol concentrations in follicular fluid of 'low responder' patients.

The study was undertaken to examine any differences existing in total cortisol concentrations in the follicular fluid (FF) of pre-ruptured follicles between 'low responder' patients (group 1, n = 20) and 'good responder' patients (group 2, n = 15). The groups were defined according to how many oocytes had been retrieved during the previous in-vitro fertilization procedure (group 1: three or fewer; group 2: more than three) and total oestradiol concentration at previous in-vitro fertilization (IVF) (group 1: < or = 500 pg/ml; group 2: > 500 pg/ml). All patients were aged 36-43 years (group 1 mean +/- SD: 38.2 +/- 4.7; group 2: 32.1 +/- 3.8 years) and were diagnosed with tubal or unexplained infertility. The total FF cortisol concentrations obtained in conjunction with an IVF procedure were assayed and related to oocyte fertilization. Follicular fluid was analysed for total cortisol content. Only follicles between 19 and 20 mm diameter were analysed in both groups. After aspiration of blood-free FF, total cortisol concentrations were measured by radioimmunoassay, designed for the quantitative measurement of cortisol, and related to oocyte fertilization. Total cortisol concentration in FF from fertilized oocytes was 9.7 +/- 0.6 microg/ml (mean +/- SD) in group 1 compared to 9.2 +/- 4.4 microg/ml in group 2 (not statistically significant). Total cortisol concentrations were not associated with oocyte fertilization and no difference between the groups was found in total cortisol concentrations in the FF of unfertilized oocytes or empty follicles.

Adult↗
PubMed1998

Hysterosalpingography with a balloon catheter versus a metal cannula: a prospective, randomized, blinded comparative study.

A prospective, randomized, blinded study was conducted to compare the use of a balloon catheter for performing hysterosalpingography (HSG) with the use of a traditional metal cannula. Sixty-one consecutive women who underwent HSG for evaluation of infertility were prospectively randomized to undergo the procedure with either a metal cannula (n = 31) or the balloon catheter (n = 30). The HSG procedure was identical in both groups. HSG using the balloon catheter, compared to the metal cannula, required significantly less fluoroscopic time (57.4 +/- 17.6 versus 75.6 +/- 40.5 s), smaller amounts of contrast medium (7.8 +/- 3.9 versus 20.1 +/- 15.8 ml), produced less pain (3.8 +/- 2.0 versus 5.6 +/- 2; on a scale of 1-10), and was easier for the physician to perform (8.8 +/- 1.1 versus 6.4 +/- 1.9; on a scale of 1-10) (P < 0.01). Eight patients (13%) were diagnosed as having proximal tubal occlusion. It was possible to offer an immediate transcervical tubal catheterization for further diagnosis and treatment of the occlusion only to the five patients with this condition from the balloon catheter group. We conclude that the balloon catheter is superior to the traditional metal cannula for performing HSG. Furthermore, if proximal tubal occlusion is diagnosed, an immediate selective salpingography and transcervical tubal catheterization can be performed without the need to replace the cannula or to reschedule the patient.

Adult↗
PubMed1998

Difficult or repeated sequential embryo transfers do not adversely affect in-vitro fertilization pregnancy rates or outcome.

In order to assist the medical team in the decision-making process and in adequate counselling of patients when encountering technical difficulties at the time of embryo transfer, we investigated the effect of difficult embryo transfer, with or without the need for cervical dilatation or repeated sequential attempts because of retained embryos in the catheter system, on in-vitro fertilization (IVF) pregnancy rates and outcome. A total of 854 consecutive embryo transfer procedures were prospectively categorized as (i) easy (smooth, unforced), (ii) difficult (requiring uterine manipulation or increased force or cervical grasping and/or accompanied by trauma), (iii) requiring cervical dilatation, or (iv) multiple (two or three) sequential attempts because of embryos retained in the catheter system. Embryo transfer was easy in 734 cases (85.9%). It was difficult in 72 (8.4%), cervical dilatation was required in 21 (2.5%), and one or two repeated attempts were needed in 27 cases (3.2%). Pregnancy rates for the different categories of embryo transfer were 23.3, 23.6, 23.8 and 29.6% respectively. There were no significant differences in the percentage of the ongoing/delivered pregnancies for the different categories of embryo transfer (69, 64.6, 60 and 62.5% respectively). There were no significant differences in the distribution of embryo transfer types among the six infertility specialists who performed the procedures. To conclude, embryo transfers that are difficult to perform or that require cervical dilatation or repeated attempts do not adversely affect pregnancy rates and outcome following IVF. Cervical dilatation, if needed for patients with cervical stenosis, should be performed at the time of the embryo transfer and not earlier. Surgical transmyometrial embryo transfer or rescheduling patients for delayed embryo transfer could be avoided in most patients. This information is important for patient management and counselling in cases of embryo transfer that are not easy to perform.

Decision Making↗
PubMed1998

Fertility in anovulatory patients after primary cesarean section.

OBJECTIVE: To evaluate the fertility potential after primary cesarean section (CS) in anovulatory patients treated for ovulation induction with gonadotropins. STUDY DESIGN: A controlled, prospective study was conducted on 97 anovulatory patients who delivered a neonate either abdominally or vaginally after ovulation induction with human menopausal gonadotropin/human chorionic gonadotropin (hMG/hCG). After four cycles of hMG/hCG therapy, cumulative pregnancy rates and abortions were observed. In both groups, patients who did not conceive underwent hysterosalpingography to evaluate uterine and tubal patency. RESULTS: The cumulative pregnancy rate in the anovulatory, post-cesarean section patients treated with hMG/hCG was 61.9%, as compared to 59.6% in the control group (statistically nonsignificant). The abortion rate was similar in both groups. CONCLUSION: The risk of uterine or tubal infertility is probably not substantially increased in patients on whom uncomplicated cesarean sections have been performed. Anovulatory patients who conceive after treatment with gonadotropins and deliver abdominally should be referred for medical treatment before evaluation of any uterine or tubal infertility.

Adult↗
PubMed1997

Gonadotropins and glucocorticoid therapy for "low responders"--a controlled study.

PURPOSE: A randomized, nonplacebo controlled study was conducted to determine the effect of dexamethasone supplementation to a protocol of gonadotropin therapy in 42 "low-responder patients" aged 32 to 43 years. METHODS: All underwent at least two previous cycles treated by gonadotropins for unexplained infertility, or anovulation. Human menopausal gonadotropin was started on day 4 of the menstrual cycle combined with dexamethasone 0.5 mg administered nightly, as an adjuvant. A group of "low responders" who did not receive dexamethasone served as the controls. The number of follicles, total amount of gonadotropins used, time required for stimulation, fertilization, peak estradiol levels and pregnancy rate were evaluated. RESULTS: The number of developing follicles, estradiol levels, fertilization rate and pregnancy rate did not differ significantly. CONCLUSIONS: Although certain beneficial effects were observed in the literature in some of the infertile patients treated with corticosteroids, the overall results did not support daily, low-dose dexamethasone (long-acting corticosteroid) as a clinically useful adjuvant therapy for "low responders" during gonadotropin therapy.

Adult↗