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Biomedical subjects

H M Vemer

Publications and source records attributed to H M Vemer.

At least 37 records · Page 2Linked to original sources

Cell of the mucous membrane of the female genital tract in culture: a comparative study with regard to the histogenesis of endometriosis.

Cellular elements from the mucous membrane of the uterus and oviducts and from peritoneal washings were cultured. The in vitro behavior of these cells was compared to elucidate the histogenesis of endometriosis and the role of various diagnostic procedures. In 65% of the cultured material obtained by uterine-tubal flushing, proliferating cells of the uterine-tubal mucous membrane were present. Their morphology and behavior corresponded to those of cultured cells obtained by separate washing of the uterine cavity and the tubes, respectively, curetted material, and biopsies of endometriosis lesions. Epithelial and stromal cells were identified using phase contrast microscopy, electron microscopy, and immunohistochemical methods. These cell types did not occur in peritoneal washings before the flushing of uterus and tubes. It was therefore assumed that they were detached and transported to the pelvic cavity during the above-mentioned procedures. In view of their intensive proliferation they may form the basis in the development of nodules of endometriosis. This would support the implantation theory concerning the pathogenesis of endometriosis. Interactions between epithelial and mesothelial cells point to the possible role of the latter in encapsulating the endometrial elements.

Cell Communication↗

Importance of sperm motility after capacitation in interpreting the hamster ovum sperm penetration assay.

Routine semen analysis and a zona-free hamster ovum sperm penetration assay (SPA) were carried out for 220 men from a group of infertile couples. The grade of sperm motility was determined after a preincubation period. For both the normal and abnormal semen samples, the number of positive SPAs was significantly higher when the postcapacitation motility was normal. This difference was observed also when the routine semen characteristics of density, motility, and morphologic features were considered separately regarding their relationship with the SPA. Motility after preincubation showed the most significant positive correlation with the SPA result. Therefore, the SPA score should be limited to semen samples showing adequate postincubation motility.

Animals↗

Survival of spermatogonial stem cells in the rat after split dose irradiation during LH-RH analogue treatment.

A rat model has been created in which a single injection of an LH-RH analogue depot preparation (Zoladex, ICI 118630) produced a temporary interruption of the pituitary-gonadal axis. This effect applied during irradiation was investigated as a possible mechanism to protect the testis from radiation damage. A local testicular irradiation dose of 6.0 Gy was given either as a single dose or as a fractionated (2 X 3.0 Gy) dose at different time intervals ranging from 8 to 72 h. Stem cell survival was measured 11 weeks after irradiation by means of the repopulation index and the number of haploid cells (spermatids) measured by flow cytometry. Serum gonadotrophins and testosterone concentrations were measured to evaluate hormonal recovery. No significant differences were observed between serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone and the duration of the fractionation interval. Stem cell survival was higher following fractionated irradiation in comparison with the single dose. For the 8 h interval an increase in recovery ratio was found, amounting to a factor of 5 of the single dose value. The fluctuating pattern of the recovery curves indicated changes in radiosensitivity of stem cells. The combination of hormonal inhibition of spermatogenesis and fractionated irradiation led to a decrease in the absolute numbers of stem cells. However, the stem cell recovery curves were identical to those seen without hormonal inhibition. It was concluded that hormonal pretreatment with Zoladex during split dose irradiation had no protective effect on stem cell survival.

Animals↗

The differences between findings at laparoscopy and at subsequent fertility surgery.

In a series of 42 patients, the findings during fertility microsurgery were compared to the findings at both laparoscopy performed by referring gynaecologists and re-laparoscopy performed in our regimen. Since significantly fewer discrepancies were found in the latter group, this re-laparoscopy may be considered useful and justified. The importance of meticulous laparoscopy is emphasized.

Endometriosis↗

Treatment with a luteinising hormone-releasing hormone analogue (Buserelin) in danazol-resistant endometriosis patients.

Luteinising hormone-releasing hormone agonist (Buserelin) therapy administered for a period of 6 months in 4 patients with longstanding, severe, danazol-resistant endometriosis, was found to be effective in reducing all complaints related to endometriosis. From 2 weeks on, nearly half of the E2 determinations were below the sensitivity level of the assay, while the other values were predominantly in the range of the early follicular phase. Side effects associated with the induced hypoestrogenemia were mild and well tolerated. After six months of follow-up without treatment, one patient who desired pregnancy conceived shortly after cessation of therapy and one patient showed lasting amelioration of her complaints. The symptoms relapsed in the other two, possibly due to inadequate dose and/or duration of treatment.

Adult↗

Effects of danazol on spermatogenesis in adult rats.

Adult male Wistar rats were treated with Danazol (4 mg/day s.c.) for 52 days. The drug produced a marked, rapid drop in serum testosterone concentrations to very low levels and caused a slower decrease in serum FSH, LH and testis weight. Flow cytometric analysis of testicular cell suspensions showed a decline in the absolute numbers of haploid cells (spermatids), tetraploid cells (mainly pachytene spermatocytes) and of cells in the S-phase of the division cycle, suggesting that Danazol inhibited proliferation of spermatogonia and/or primary spermatocytes. Histological counting of the different types of spermatogonia, however, revealed no significant change in their numbers during Danazol treatment. It is concluded that Danazol inhibited spermatogenesis primarily after the preleptotene stage of primary spermatocytes.

Animals↗

Effects of a single injection of a new depot formulation of an LH-releasing hormone agonist on spermatogenesis in adult rats.

Adult male Wistar rats were treated with a single injection (500 micrograms s.c.) of a new biodegradable depot formulation of the LH-releasing hormone (LHRH) analogue [D-Ser(But)6]AzGly10-LH-RH (Zoladex; ICI 118,630) to evaluate its potential for inhibiting spermatogenesis. The drug produced a marked (P less than or equal to 0.05) decrease in serum concentrations of FSH, LH and testosterone with a maximum effect 14 days after treatment. Since striking focal histological changes were seen in the testis after only 1 week, at a time when changes in serum gonadotrophins were minimal, there may be a direct effect of the LHRH analogue on spermatogenesis. Degenerative changes in germ cells as well as Sertoli cells could be observed. Flow-cytometric analysis of testicular cell suspensions showed a significant decline in the absolute numbers of haploid cells (spermatids), tetraploid cells (mainly pachytene spermatocytes) and of the numbers of cells in the S-phase of the cell cycle. This suggests that the drug also inhibits proliferation of spermatogonia and/or primary spermatocytes. Testis weight, serum hormone concentrations, and histological and cytological parameters returned to essentially normal values 52 days after the injection. It is concluded that this new method of administration may have practical and pharmacokinetic advantages for the purpose of reversible inhibition of spermatogenesis.

Animals↗

Experimental hydrosalpinx and salpingostomy in rabbits.

In 137 oviducts of New Zealand white rabbits different kinds of occlusion techniques were tested to induce hydrosalpinges. In 99 oviducts ligatured or clipped both at the fimbrial end and at the ampullary-isthmic junction 67 hydrosalpinges were achieved, whilst in 34 oviducts ligatured or clipped only at the fimbrial end one hydrosalpinx occurred. Most severe histological changes were seen after double clipping. Ligation of the blood vessels to and from the ampulla of 4 oviducts caused no hydrosalpinx formation. After cuff salpingostomy a higher number of patent oviducts was found than after double-loop salpingostomy.

Animals↗

The influence of exogenous oestradiol benzoate on the pituitary responsiveness to LHRH during the puerperium in women.

The FSH and LH compared to 25 micrograms LHRH was measured in lactating women and the results compared to a similar group in whom lactation was suppressed by administration of bromocriptine shortly after delivery. The response was also measured in both groups after "challenge" with oestradiol benzoate. In lactating women the FSH response to LHRH was diminished following the oestradiol challenge, as compared with that in unchallenged women. At the same time the LH responses were low in both circumstances, indicating a negative feedback effect of oestradiol. However, the oestradiol challenge resulted in a significantly increased response of FSH and LH to LHRH in bromocriptine-treated puerperal women, i.e. a positive feedback effect of oestradiol. We concluded that this and previous experiments favour the hypothesis that the lactational amenorrhoea during hyperprolactinaemia is caused by hypothalamic changes due to a predominance of the negative feedback system.

Estradiol↗

The dynamics of prolactin secretion during the puerperium in women.

This study deals with serum prolactin concentrations during various conditions in the early puerperium in an attempt to investigate some characteristics of the mechanisms responsible for the regulation of the lactotropes. In nursing, in non-nursing, non-medicated and in non-nursing, bromocriptine-treated women prolactin and 17 beta-oestradiol were measured during the early puerperium. In the first and the third group this was repeated during and after challenge with oestradiol-benzoate. The pituitary responsiveness to TRH was also determined in these two groups, challenged and unchallenged with oestradiol-benzoate. Nursing women had higher prolactin levels than the non-nursing groups, while bromocriptine decreased prolactin to very low levels. Non-nursing non-medicated women had prolactin values between those of nursing and those of bromocriptine-treated mothers. The already elevated prolactin levels in nursing women were not influenced by chronic oestradiol administration. In non-nursing puerperal women treated with bromocriptine, exogenous oestradiol caused a significant rise in plasma prolactin. The prolactin response to TRH in nursing women was clearly reduced in comparison with the normal menstrual cycle. In the bromocriptine-treated group the basal concentration of prolactin and its response to TRH stimulation was similar to normal non-pregnant women. In nursing and in non-nursing women treated with bromocriptine prolactin responses to TRH were increased after oestradiol challenge.

Bromocriptine↗

Effects of testicular irradiation on stem cell survival, hormonal environment and spermatogenic cells in Wistar rats.

Adult male Wistar rats were exposed to 3.0 Gy local testicular irradiation. Testes of irradiated and non-irradiated rats were examined histologically and flow cytometrically, at several intervals up to 78 days after irradiation. Concentrations of follicle-stimulating hormone, luteinizing hormone and testosterone determined at these intervals were not different from those of controls. The survival of stem cells were measured 11 weeks after irradiation (with doses varying from 1.0 Gy to 6.0 Gy at 0.6 Gy/min) by means of the repopulation index and by the number of haploid cells (spermatids). Correlation between both methods and relation to stem cell survival were discussed. The dose response curves yielded D0 values of stem cell survival of 2.33 +/- 0.06 Gy (repopulation index) and 2.08 +/- 0.08 Gy (number of haploid cells). The D0 value of the rat was not much different from that found in mice. It was concluded that the used parameters can offer insight when studying hormonal substances during irradiation.

Animals↗