Biomedical subjects

R Har-Nir

Publications and source records attributed to R Har-Nir.

6 recordsLinked to original sources

PubMed1995

Do spermatozoa secrete motility enhancing factor?

OBJECTIVES: To determine whether medium conditioned with human spermatozoa was capable of enhancing sperm motility and penetration ability. DESIGN: Paired aliquots of washed spermatozoa were allowed to incubate for nine different incubation periods, ranging from 15 to 240 minutes in 37 degrees C in humidified atmosphere with 5% CO2. After this, they were centrifuged at 600 x g for 6 minutes. The conditioned medium was removed from one tube of each pair and replaced with fresh medium. In the other tube of the same pair the sperm pellet was resuspended in the same medium. In a second set of experiments, conditioned medium was removed from tubes containing samples of spermatozoa after different predefined incubation periods. This was used to replace medium that had been removed from sperm cells that had been incubated for 120 minutes. Motility and penetration of zona-free hamster eggs were assessed. RESULTS: Removal of the incubation medium at times between 15 to 240 minutes resulted in sperm that showed a gradual decrease in motility and penetration ability followed by a gradual increase in motility and penetration ability, i.e., an inverted bell-shaped effect. The addition of conditioned medium obtained after different periods of incubation to spermatozoa where medium was removed after 120 minutes of incubation resulted in an increase in sperm motility and penetration ability. The longer the medium was conditioned with spermatozoa the more prominent the effect on sperm motility and penetration ability, with maximal effect observed with medium conditioned for 120 minutes. CONCLUSIONS: Medium conditioned with human spermatozoa enhances sperm motility and penetration ability.

Culture Media, Conditioned↗

PubMed1994

Ultrasound transmission gel in the vagina can impair sperm motility.

The effect of ultrasound transmission gel on sperm motility was assessed because of a few unsatisfactory post-coital tests, encountered after vaginal ultrasonography in otherwise normal couples. Swim-up samples of spermatozoa from donors and patients with asthenozoospermia were incubated in ultrasonic transmission gel at various concentrations. Sperm progressive motility and viability were checked. Donor sperm progressive motility declined from 90.9 +/- 2.5% (mean +/- SD) to 30.6 +/- 2.7% (P < or = 0.001) within 18 h at a gel concentration of only 10% (by volume). There were no progressive motile spermatozoa after incubation in 80% gel. In the swim-up fraction from asthenozoospermic patients, motility declined from 92.2 +/- 2.5% to 11.6 +/- 2.1% (P < or = 0.001) within 130 min at a gel concentration of 10% (by volume). Eosin staining for viability demonstrated that the loss of motility was mostly due to loss of viability. The use of ultrasound transmission gel should be avoided during follicular follow-up close to the date of expected ovulation in couples who practise dated natural intercourse or cervical insemination. Normal saline is an adequate substitute in this period with relatively large follicles.

Cell Survival↗

PubMed1993

Trophoblasts protect the inner cell mass from macrophage destruction.

Several mechanisms have been suggested to account for the survival of the semiallogeneic fetus in the maternal uterus. However, no data are available to explain how the blastocyst resists the high number of macrophages in the uterus at the time of implantation. The present study examines the in vitro development of murine 3.5-day-old syngeneic or semiallogeneic blastocysts in the presence of nonactivated or lipopolysaccharide (LPS)-activated macrophages. It was found that the in vitro development of blastocysts was undisturbed by the presence of nonactivated or LPS-activated macrophages. The outgrowing trophoblasts were not only nonadhesive to the macrophages but also repelled them actively, thus preventing them from reaching the inner cell mass (ICM). Removing the zona pellucida by use of pronase or killing the ICM by irradiation did not alter the repulsion of macrophages by the trophoblasts. On the other hand, removal of the trophectoderm by antibody and complement treatment rendered the macrophages adhesive and destructive to the ICM. Four of 15 ICM (27%) were destroyed by nonactivated macrophages, and all of the ICM (15/15) were destroyed by LPS-activated macrophages. It is noteworthy that the addition of colchicine, cytochalasin B, proteinase inhibitors, anti-transforming growth factor-beta (TGF beta) antibodies, and indomethacin had no effect on the repulsion of macrophages by the trophoblasts. Therefore, it seems that microtubular proteins, microfilaments, extracellular matrix-degrading enzymes, TGF beta, and prostaglandins are not involved in the repulsion process. These results indicate that trophoblasts protect the ICM from the destructive action of macrophages by a repulsion mechanism of an as yet unknown nature.

Animals↗

PubMed1986

The hormonal response of patients with polycystic ovarian disease to subcutaneous low frequency pulsatile administration of luteinizing hormone-releasing hormone.

Four patients with oligoamenorrhea manifesting hormonal and clinical features of polycystic ovarian disease (PCOD) were selected for treatment. All patients had high luteinizing hormone (LH) levels and a basal LH/follicle-stimulating hormone (FSH) ratio of greater than 3. Three of them had high androgen levels with normal adrenal cortical function. The four patients were treated for 12 cycles by pulsatile LH-releasing hormone (LH-RH) subcutaneously. Frequency of pulses varied between once in every 120 to once in every 400 minutes in consecutive cycles, in an attempt to reverse LH/FSH ratio. The dose of LH-RH varied between 20 and 40 micrograms/pulse. Treatment was monitored hormonally by the determinations of LH, FSH, 17 beta-estradiol, prolactin, progesterone, testosterone (T) (total and free), androstenedione (delta 4A), dehydroepiandrosterone sulfate (DHEA-S), and sex hormone-binding globulin (SHBG) every 2 days. The most striking change was the lowering of the LH/FSH ratio to the normal range, due to LH decrease and FSH increase with a pulse frequency of 180 to 240 minutes. DHEA-S levels reversed to normal in two patients and were reduced in one patient. T and delta 4A levels returned to normal with elevation to normal of SHBG. These hormonal improvements did not result in ovulation as expected (2 of 12 cycles). It may be assumed that either subcutaneous administration is inadequate in PCOD patients or that the frequency of pulses needed to correct the hormonal disturbances in PCOD patients differs from that needed for ovum maturation and ovulation.

Adult↗

PubMed1984

Increased placental concentrations of 25-hydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 in pregnant rats treated with human chorionic gonadotropin.

Pregnant rats were injected intrajugularly with 2500 i.u. human chorionic gonadotropin (HCG) toward the end of gestation (days 18-19) and 7.0 pmoles of tritiated 25-hydroxyvitamin D3 [( 3H]25(OH)D3) the following day. They were sacrificed ten to 24 hours later. [3H]25(OH)D3 and the in vivo produced [3H]24,25-dihydroxyvitamin D3 [( 3H]24,25(OH)2D3) in lipid extracts from maternal serum, kidneys, placenta and fetal tissues were separated by Sephadex LH-20 chromatography, and high performance liquid chromatography (HPLC). HCG treatment of pregnant rats increased significantly 25(OH)D3 levels in the placenta and kidneys and 24,25(OH)2D3 level in the placenta. Fetal metabolites levels were unaffected by HCG treatment. Serum and kidney levels of 25(OH)D3 and 24,25(OH)2D3 in pregnant rats were significantly lower than in non-pregnant rats. Serum and kidney levels of both metabolites in non-pregnant female rats treated with HCG did not differ from the untreated controls. HCG may, therefore, be involved in regulation of fetoplacental vitamin D metabolism.

Animals↗

PubMed1983

Vitamin D3 metabolites in rat epididymis: high 24,25-dihydroxy vitamin D3 levels in the cauda region.

Normal male rats received six subcutaneous injections of 8.0 pmoles of tritiated 25-hydroxy vitamin D3 ([3H]25(OH)D3) or one intrajugular injection of 8.0 pmoles of high specific radioactivity [3H]-25(OH)D3. Lipid extracts of several tissues including the reproductive organs were subjected to sephadex LH-20 chromatography to determine the tissue distribution of the injected material and of the in vivo produced dihydroxylated cholecalciferol metabolites. The nature of the putative 25(OH)D3 and the 24,25-dihydroxy vitamin D3 (24,25(OH)2D3) from epididymis tissue was confirmed by high performance liquid chromatography (HPLC). The epididymis levels of 24,25(OH)2D3 were considerably higher in the cauda epididymis compared to kidney and caput epididymis levels. The other metabolites levels in this tissue were similar to those determined in the kidneys. The amounts of the three metabolites found in all other tissues were well below the cauda epididymis or kidney levels. The findings suggest a possible physiological role for 24,25(OH)2D3 in the epididymis, and are also consistent with data of others which indicated a possible action of 1,25-dihydroxy vitamin D3 (1,25(OH)2D3) in rat reproductive tissues.

24,25-Dihydroxyvitamin D 3↗