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Dive into the research topics where Gedalia Paz is active.

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Featured researches published by Gedalia Paz.


Fertility and Sterility | 1976

The temperature, pH, and partial pressure of oxygen in the cervix and uterus of women and uterus of rats during the cycle.

Gideon Yedwab; Gedalia Paz; Thomas Z. Homonnai; Menahem P. David; P. F. Kraicer

Changes in the temperature, pH, and partial pressure of oxygen (PO2) in the cervical canal and cavum uteri were measured in women with or without an intrauterine device and in the uteri of rats throughout the cycle. Only the PO2 exhibited significant variations, rising during the ovulatory phase in both cervices of women and uteri in rats. It is speculated that the rise in PO2 is related to the function of these organs as reservoirs for spermatozoa.


Fertility and Sterility | 1978

The Cation Composition of the Seminal Plasma and Prostatic Fluid and its Correlation to Semen Quality

Zvi T. Homonnai; Haim Matzkin; Nachum Fainman; Gedalia Paz; P. F. Kraicer

The concentrations of calcium, magnesium, and zinc were measured by atomic absorption spectrometry. The concentrations of all three cations were found to be strongly correlated with one another and with acidity (pH). Analysis of the relative concentrations in prostatic fluid, split ejaculates, and whole seminal plasma confirmed an almost exclusively prostatic origin of these cations. Semen quality, as judged by motility, vitality, concentration, and morphology of spermatozoa, was inversely related to cation concentrations. Therefore, we recommend adoption of the measurement of seminal divalent cations as part of the routine andrologic examination.


Human Genetics | 1998

Increased rate of nondisjunction in sex cells derived from low-quality semen

Sharona Finkelstein; E. Mukamel; Haim Yavetz; Gedalia Paz; Lydia Avivi

Abstract The relationship between chromosomal nondisjunction and semen quality was studied in two groups of males who differ highly in their semen quality: 12 individuals with low-quality semen caused by varicocele, and 8 subjects with high-quality semen, selected from sperm donors for in vitro fertilization. Chromosomal nondisjunction was inferred from the rate of disomy found in mature sperm cells. To determine the rate of disomy, we applied fluorescence in situ hybridization using satellite-specific probes for chromosomes 1, 15, 18, X and Y. In sperm cells of males with low-quality semen, the mean rate of disomy for each of the autosomes and of hetero-disomy for the sex chromosomes (XY) was significantly higher than that observed in the high-quality semen samples: more than 15-fold higher for chromosomes 1 and 15, and 7-fold higher for chromosomes 18 and XY. Yet, the homo-disomy rate for each of the sex chromosomes (XX and YY) was almost the same in both types of semen. The large discrepancy between the low- and high-quality semen in the rate of sex chromosome hetero-disomy versus the similar rate of homo-disomy strongly suggests that the abnormal chromosomal segregation in meiocytes of males with low-quality semen resulted from chromosomal nondisjunction at the first meiotic division. The results indicate that men showing poor semen quality are at an increased risk for meiotic nondisjunction, similar to women at the end of their reproductive years.


Fertility and Sterility | 2002

Sertoli cell maturation in men with azoospermia of different etiologies

Batia Bar-Shira Maymon; Leah Yogev; Gedalia Paz; Sandra E. Kleiman; Letizia Schreiber; Amnon Botchan; Ron Hauser; Haim Yavetz

OBJECTIVEnTo evaluate the involvement of Sertoli cell in different spermatogenic disorders.nnnDESIGNnRetrospective case-control study.nnnSETTINGnTeaching hospital.nnnPATIENT(S)nAzoospermic men who underwent testicular biopsy for sperm recovery in preparation for intracytoplasmic sperm injection.nnnINTERVENTION(S)nTesticular biopsy evaluation by quantitative immunohistochemistry for the immature Sertoli cell markers anti-Müllerian hormone and cytokeratin 18 (CK-18).nnnMAIN OUTCOME MEASURE(S)nRelative area of immature Sertoli cells in testes with focal spermatogenesis, spermatocyte maturation arrest, or normal spermatogenesis.nnnRESULT(S)nThe relative area occupied by immature Sertoli cells, as revealed by anti-Müllerian hormone and CK-18 expression, was highest in the 11 men with focal spermatogenesis. In the group representing normal spermatogenesis (obstructive azoospermia, 6 men) and in the group characterized by spermatocyte maturation arrest (6 men), the areas occupied by anti-Müllerian hormone- and CK-18-positive cells were minimal.nnnCONCLUSION(S)nDifferent etiologies underlie the spermatogenic disorders reported in this study. In focal spermatogenesis with high anti-Müllerian hormone and CK-18 expression, the spermatogenic impairment is associated with the presence of immature Sertoli cells. The detection of normal mature Sertoli cells in the spermatocyte maturation arrest group indicates that the spermatogenic defect that is accompanied by an impairment of meiosis is intrinsic to the germ line without affecting Sertoli cell differentiation.


Fertility and Sterility | 1979

Sperm Penetration In Vitro: Correlations Between Parameters of Sperm Quality and the Penetration Capacity

Menachem P. David; Ami Amit; Arie Bergman; Gideon Yedwab; Gedalia Paz; Zvi T. Homonnai

A nonlinear regression analysis was used in order to fit a logistic model to 200 runs of human ejaculated spermatozoa penetrating cervical mucus of good quality. The data revealed excellent correlation between the number of sperm penetrating (sigma penetration, SP) and the motility (r = 0.776) and vitality (r = 0.534) of the spermatozoa. The percentage of abnormal spermatozoa found in the ejaculate was negatively correlated (r = -0.649), while sperm concentration showed a poor correlation with SP (r = 0.327). Furthermore, concentration was shown to have no effect in samples containing over 5 million sperm/ml. The conclusion of this study is that the two major parameters of sperm quality determining the capacity of spermatozoa to penetrate cervical mucus are motility and the presence of normal forms of spermatozoa.


Contraception | 1984

Phenoxybenzamine — An effective male contraceptive pill

Z. T. Homonnai; Michael Shilon; Gedalia Paz

Phenoxybenzamine (PBZ), administered in doses up to 20 mg/day, caused aspermia following male orgasm. This led to the development of a male contraceptive pill, PBZ being the active drug. It has been shown that small doses of the drug do not change the hormonal balance of the body, nor do they affect blood pressure. In 2 to 3 days, PBZ blocks ejaculation; this is fully reversed with the cessation of treatment. The drug does not affect semen quality (testicular function), even after a long period of medication. During treatment, the vas deferens, the ampulla and the ejaculatory ducts are probably paralyzed. Cessation of medication brought full recovery of these effects and the reappearance of normal ejaculation. Men complaining of premature ejaculation reported marked improvement in their sexual performance. The recommended regimen for administering PBZ as a male contraceptive is discussed.


Fertility and Sterility | 1977

Immunoreactive Insulin in Serum and Seminal Plasma of Diabetic and Nondiabetic Men and its Role in the Regulation of Spermatozoal Activity

Gedalia Paz; Zvi T. Homonnai; Daniel Ayalon; Tova Cordova; P. F. Kraicer

Concentrations of immunoreactive insulin (IRI) and, in some cases, testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured in serum and seminal plasma (SP). IRI levels were usually higher in SP. They were unaffected by masturbation; circulating testosterone, LH, and FSH levels were also unaffected. The IRI concentration was higher in the second (vesicular) fraction of split ejaculates. Semen quality was unrelated to IRI in SP in normal and diabetic (chlorpropamide-maintained) men. The addition of insulin in vitro to washed spermatozoa from diabetic and nondiabetic men had no effect on oxygen and glucose uptake or on lactate production and spermatozoal motility. Furthermore, administration of L-arginine to infertile men for 3 months (4 gm/day) was followed in four of seven men by significant increases in IRI concentrations in blood and SP. However, neither semen quality nor fertility was improved.


Fertility and Sterility | 1992

Fresh and frozen-thawed human sperm bind in a similar pattern to the zona pellucida in the hemizona assay.

Leah Yogev; Haim Yavetz; Zvi T. Homonnai; Yehuda Hiss; Gedalia Paz

This study evaluated the impact of sperm cryopreservation on sperm quality. The HZA was used to test the binding capacity of fresh as opposed to frozen-thawed sperm from 12 donors. Fresh and frozen-thawed sperm motility was 47% +/- 1.5% and 24% +/- 3.8% (mean +/- SE), respectively. However, the number of sperm cells attached to the hemizonae was 75 +/- 12.0 and 74 +/- 11.9, respectively. We conclude that cryopreservation results in a reduced number of motile sperm cells but does not adversely affect the ability of rescued sperm cells to bind to the ZP. The study also supports the use of frozen-thawed rather than fresh donor sperm for control in the HZA procedure.


Contraception | 1975

A direct effect of α-chlorohydrin on motility and metabolism of ejaculated human spermatozoa

Zvi T. Homonnai; Gedalia Paz; Adin Sofer; Gideon A. Yedwab; Perez F. Kraicer

Abstract Human spermatozoa were incubated in vitro in the presence of α-chlorohydrin at concentrations which inhibited motility, but which were not spermicidal. The inhibition of motility was not reversed by washing or by addition of α-glycerophosphate. Metabolic activity of the spermatozoa was reduced, as measured by glucose, oxygen uptake and lactate production. Endogenous respiration was not affected. Cyclic AMP levels were reduced. Thus, at least part of the adversed effects of α-chlorohydrin on male fertility may be due to direct inhibitory action on the spermatozoa.


Asian Journal of Andrology | 2013

Preservation of sperm of cancer patients: extent of use and pregnancy outcome in a tertiary infertility center

Amnon Botchan; Shiri Karpol; Ofer Lehavi; Gedalia Paz; Sandra E. Kleiman; Leah Yogev; Haim Yavetz; Ron Hauser

Sperm cryopreservation is the best modality to ensure future fertility for males diagnosed with cancer. The extent to which cryopreserved sperm is actually used for impregnation, the fertility treatment options that are available and the success rates of these treatments have not been investigated in depth. The medical records of 682 patients who cryopreserved sperm cells due to cancer treatment were analyzed. Seventy of these patients withdrew their frozen sperm for fertility treatments over a 20-year period (most within the first 4 years after cryopreservation). Sperm quality of different malignancies and outcomes of assisted reproduction treatment (ART) for pregnancy achievement in relation to the type of treatment and the type of malignancy were evaluated. The results showed that the rate of using cryo-thawed sperm from cancer patients for fertility treatments in our unit was 10.3%. Sperm quality indices differed between different types of malignancies, with the poorest quality measured in testicular cancer. Conception was achieved in 46 of the 184 ART cycles (25%), and resulted in 36 deliveries. The use of intracytoplasmic sperm injection (ICSI) methodology yielded a significantly higher pregnancy rate (37.4%) than intrauterine insemination (IUI; 11.5%) and was similar to other groups of infertile couples using these modalities. In vitro fertilization (IVF) failed to produce pregnancies. In conclusion, the rate of use of cryopresseved sperm in cancer patients is relatively low (10.3%). Achievement of pregnancies by ICSI presents the best option but when there are enough stored sperm samples and adequate quality, IUI can be employed. Cryopreservation is nevertheless the best option to preserve future fertility potential and hope for cancer patients.

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Zvi T. Homonnai

Weizmann Institute of Science

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Haim Yavetz

Tel Aviv Sourasky Medical Center

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Leah Yogev

Tel Aviv Sourasky Medical Center

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Amnon Botchan

Tel Aviv Sourasky Medical Center

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Batia Bar-Shira Maymon

Tel Aviv Sourasky Medical Center

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Haim Matzkin

Weizmann Institute of Science

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