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Dive into the research topics where Yona Barak is active.

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Featured researches published by Yona Barak.


Fertility and Sterility | 1998

Pregnancy and birth after transfer of embryos that developed from single- nucleated zygotes obtained by injection of round spermatids into oocytes

Yona Barak; Abraham Kogosowski; Shlomit Goldman; Yigal Soffer; Yael Gonen; Jan Tesarik

OBJECTIVE To use injection of spermatids into oocytes as a mode of infertility treatment in cases in which spermatozoa are not available. DESIGN Prospective clinical evaluation and case report. SETTING In Vitro Fertilization Unit, Herzliya Medical Centers, Herzliya-on-Sea, Israel. PATIENT(S) Thirteen couples with male factor infertility in which the male partner lacked spermatozoa in the ejaculate or testicular biopsy samples. INTERVENTION(S) Round spermatid injection and elongated spermatid injection into oocytes. MAIN OUTCOME MEASURE(S) Evaluation of the rate of two-pronucleated and single-nucleated zygote development. RESULT(S) The rate of two-pronucleated zygote development after round spermatid injection and elongated spermatid injection was relatively low (27% and 36%, respectively). Single-nucleated zygotes develop more frequently after round spermatid injection and elongated spermatid injection (35% and 17%, respectively) than after intracytoplasmic sperm injection with mature spermatozoa. A normal pregnancy and childbirth resulted from the transfer of 4 cleaving embryos, each of which developed from a single-nucleated zygote in a round spermatid injection treatment cycle with ejaculated spermatids. CONCLUSION(S) Embryos derived from single-nucleated zygotes after spermatid conception can be viable and give rise to an ongoing clinical pregnancy and childbirth.


Reproductive Biomedicine Online | 2012

Correlation between DNA defect and sperm-head morphology

Nino Guy Cassuto; André Hazout; Ibrahim Hammoud; Richard Balet; Dominique Bouret; Yona Barak; Sonia Jellad; Jean Marie Plouchart; Jacqueline Selva; Chadi Yazbeck

The utility of sperm DNA testing remains controversial. However, it may be helpful in couples with unexplained failures of multiple assisted reproductive techniques and/or recurrent abortions. This study analysed 10,400 spermatozoa of 26 patients for sperm-head morphology with high-magnification microscopy, DNA fragmentation and sperm chromatin decondensation. A significant negative correlation was demonstrated between sperm-parameters and abnormal sperm-head morphology as assessed by high magnification (score 0 according to this studys classification): concentration (r=-0.41; P=0.03), motility (r=-0.42; P=0.03), morphology (r=-0.63; P=0.0008). No correlation was found with DNA fragmentation. However, the sperm chromatin-decondensation rate of score-0 spermatozoa was twice as high as the controls (19.5% versus 10.1%; P<0.0001). This observation suggests that score-0 spermatozoa should not be selected for intracytoplasmic sperm injection.


Acta Obstetricia et Gynecologica Scandinavica | 1988

The Development of an Efficient Ambulatory In Vitro Fertilization (IVF) and Embryo TrAnsfer (ET) Program Using Ultrasonically Guided Oocyte Retrieval

Yona Barak; Joseph B. Lessing; Ami Amit; Abraham Kogosowski; Israel Yovel; Menachem P. David; M. Reuben Peyser

Until recently most of the current in vitro fertilization and embryo transfer (IVF‐ET) programs used laparoscopy for oocyte retrieval and included hospitalization in the treatment. The establishment of a successful ambulatory IVF program that uses ultrasonically guided oocyte aspiration, is described. Between August 1985 and February 1987, 384 percutaneous transvesical ultrasonically and transvaginally guided follicle aspirations were performed on 414 patients, following ovarian stimulation with hMG and hCG. Ninety two clinical pregnancies were confirmed by ultrasound. The clinical pregnancy rate was 26.8% when based on the number of embryo transfers. There were 16 multiple pregnancies (17.4%), 18 miscarriages (19.5%), and two tubal pregnancies (2.1%). The most important factors contributing toward the success of this program were rigid adherence to clinical and laboratory protocols, and the maintenance of a strict quality control. The ambulatory management was very well accepted by the patients, who during the entire period of ovarian stimulation had minimal disruption of their routine activities.


Fertility and Sterility | 1992

High initial values of β-subunits of human chorionic gonadotropin in ovum donation pregnancies indicate better implantation

Abraham Kogosowski; Ami Amit; Yona Barak; M. Reuben Peyser; Menachem P. David; Joseph B. Lessing

Fifty-five patients were treated by ovum donation, and a control group of 165 patients underwent IVF. The number of pregnancies obtained were 28 and 25, respectively. The initial beta-hCG values, as well as the PRs and implantation rates, in the ovum donation series were significantly higher than those of the IVF series. The clinical significance and potential application of these observations are discussed.


Fertility and Sterility | 1987

Estrone-3-glucuronide chemiluminescence immunoassay: an alternative method for monitoring induction of ovulation with human menopausal gonadotropin in an in vitro fertilization program

Joseph B. Lessing; M. Reuben Peyser; Susan Gilad; Ami Amit; Abraham Kogosowski; Israel Yovel; Yona Barak; Menachem P. David

A simple, rapid, and sensitive solid-phase immunoassay procedure for the determination of estrone-3-glucuronide (E1-3-G), which uses chemiluminescence as the end point in unextracted morning urine, is described. Thirty-one patients undergoing induction of ovulation in an in vitro fertilization (IVF) unit participated in the study. From day 3 of the menstrual cycle until the day of hCG administration, morning blood samples and morning urine specimens were collected for the determination of serum 17 beta-estradiol (E2) and urine E1-3-G, respectively. A good correlation was noted between E2 measured by radioimmunoassay (RIA) and the E1-3-G measured by chemiluminescence immunoassay (CIA), from day 5 up to the day of hCG administration (0.6 less than r less than 0.85, P less than 0.001). It is evident from this study that the CIA measurement of E1-3-G in morning urine is an accurate and rapid (2.5 hours) method and is convenient for monitoring induction of ovulation with human menopausal gonadotropins.


Journal of Assisted Reproduction and Genetics | 1991

The efficiency of cryopreserved semen versus fresh semen for in vitro fertilization/embryo transfer

Haim Yavetz; Joseph B. Lessing; Ami Amit; Y. Niv; Yona Barak; Israel Yovel; Menachem P. David; M. R. Peyser; Leah Yogev; Z. T. Homonnai; Gedalia Paz

The efficiency of cryopreserved donor semen versus fresh donor semen in an in vitro fertilization/embryo transfer programme was evaluated. Thirty-nine in vitro fertilization/embryo transfer cycles were performed using fresh donor semen (group A) and 74 cycles were carried out using cryopreserved semen (group B). All patients anderwent a uniform controlled ovarian hyperstimulation using high doses of human menopausal gonadotropins. Oocytes were retrieved transvaginally under ultrasound imaging. Semen (fresh or frozen-thawed) were prepared for insemination by a washing technique. Each ovum was inseminated with 500,000–600,000 motile spermatozoa. No significant difference was noted between the two groups regarding female age, duration of infertility, and number of ova retrieved per aspiration. Even though the fertilization rate in group B was significantly lower than in group A (55.5±3.8 vs 70.4±3.5,P=0,008); pregnancy rates per embryo transfer were similar-39.3 and 38.5%, respecitively.


Journal of Assisted Reproduction and Genetics | 1990

The establishment of an ovum donation program using a simple fixed-dose estrogen-progesterone replacement regimen

Abraham Kogosowski; Israel Yovel; Joseph B. Lessing; Ami Amit; Yona Barak; Menachem P. David; Reuben Peyser

Most ovum donation (OD) programs involve cycle synchronization between recipient and donor for normally cycling recipients and a complex estrogen-progesterone replacement regimen for recipients with ovarian failure. In 1987, Serhal and Craft (1) suggested the use of a fixeddose estrogen-progesterone regimen for recipients who were normally ovulatory and to those with ovarian failure. Following this protocol, and simplifying it still, the authors administered 6 mg estradiol valerate (E2) daily orally starting on day 2–6 of induced withdrawal bleeding, augmented with 100 mg progesterone in ethyl oleate (P) intramuscularly daily, starting any time between 4 days prior to and the day of oocyte pickup. All recipients underwent embryo transfer at a 2-pronuclei (2PN)-10-cell stage. A group of 21 patients underwent 26 treatment cycles, resulting in 16 pregnancies. Twelve of the patients gave birth, one to triplets, two to twins, and nine to singletons. Four patients miscarried in the first trimester of pregnancy.


Fertility and Sterility | 1995

Ultrastructural changes in sperm with improved fertilizability after treatment with egg yolk

Yona Barak; Benjamin Bartoov; Joseph B. Lessing; Fina Eltes; N. Zabludovsky; Ami Amit

OBJECTIVES To determine the existence of differences in the ultrastructural parameters between the medium-washed sperm samples of the affected and nonaffected egg yolk (EY) groups and to verify whether ultrastructural changes occur in the EY-affected spermatozoa after EY preincubation. SETTING The study was performed in the Laboratory of the IVF Unit, Serlin Maternity Hospital, and the Laboratory of Male Fertility, Bar-Ilan University, Ramat Gan, Israel. PATIENTS The positive group included 12 males who underwent 1.9 IVF cycles with 0% fertilization rate that increased to 68% after EY treatment. The negative group included 11 males with 1.2% fertilization rate in 1.1 IVF cycles with no improvement after preincubation of spermatozoa in EY. RESULTS Compared with the laboratory standard, patients of both groups exhibited a lower normalcy of the head sperm cell subcellular organelles. With EY treatment, the positive group exhibited a decrease in the frequency of some sperm head organelle specific malformations. CONCLUSIONS Fertilization capacity of mature spermatozoa might be reduced because of an excess of acrosome malformations, postacrosomal lamina, and chromatin caused by in vitro sperm manipulations. The manipulation effect may be avoided by EY treatment.


Journal of Assisted Reproduction and Genetics | 1991

Successful ovarian superovulation for in vitro fertilization in a patient with an undiagnosed intrauterine pregnancy

Joseph B. Lessing; Abraham Kogosowski; Ami Amit; Israel Yovel; Yona Barak; Menachem P. David; M. R. Peyser

laparotomy showed distended intestinal loops, many adhesions that were lysing, and a roundish formation, 7 cm in diameter, in the right adnexal site, which was removed. When it was opened, a resorbing fetus was found and diagnostic histology identified it as an extrauterine pregnancy with no evidence of tubal structures. The postsurgical course was regular and the ultrasound controls indicated normal development of the intrauterine pregnancy until 12 days after the operation, at which time the pregnancy ended in abortion (16th week).


Journal of Assisted Reproduction and Genetics | 1987

Interdepartmental unit for IVF/ET, Serlin-Hakirya Maternity Hospital, Tel Aviv, Israel.

Menachem P. David; Yona Barak; Ami Amit; Joseph B. Lessing; Abraham Kogosowski; Israel Yovel; Gedalia Paz; Zeev V. Rudick; Zvi T. Homonnai; M. Reuben Peyser

In Vitro Fertilization Department Pavilion Mrre et Enfant Centre Hospitalier Universitaire 44035 Nantes Cedex, France action of the analogue on ovarian GnRH receptors (7) or decreased ovarian androgen production might also be suspected. The use of an analogue also allows for the administration of more hMG without the fear of inducing premature luteinization. (c) No alteration in cleavage or implantation rates occurred. These different changes resulted in a significantly enhanced pregnancy rate and represent an improvement, even though the optimal regimen still remains to be determined.

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Ami Amit

Tel Aviv Sourasky Medical Center

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Joseph B. Lessing

Tel Aviv Sourasky Medical Center

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M. Reuben Peyser

Tel Aviv Sourasky Medical Center

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Gedalia Paz

Tel Aviv Sourasky Medical Center

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