Electromagnetic exposure effects the hippocampal dentate cell proliferation in gerbils (Meriones unguiculatus).

The chronic effect on hippocampal neurogenesis after exposure (30 min/day for 14 days) to a high frequency (35,53 kHz) electromagnetic field, double modulated at extremely low frequencies (ELF; 1, 8, 12, 29 and 50 Hz), was studied in young adult gerbils. Immediately after the last exposure proliferation of dentate granule cells was identified by in vivo labeling with 5-bromo-2-desoxyuridine (BrdU). Exposure to 1, 29 and 50 Hz resulted in a statistically significant reduction of cell proliferation rates, but only the 50 Hz-group manifested the effect highly significantly (-29,3 %). On the other hand, gerbils exposed to 8 and 12 Hz showed no significant change of postmitotic cell proliferation as compared with the sham treated controls. The results suggest that the effects of ELF on the granule cell proliferation are mediated by neurotransmitters and hormones which regulate hippocampal neurogenesis.

Cell culture of biopsied endometriomas after danazol/hormonal therapy: a study of growth features and fertility effects.

The growth features of cells from endometriomas biopsied from patients who had been treated with Danazol or with hormones have not been studied in vitro. Danazol is a versatile drug and despite its recognised efficacy in controlling endometriosis, little is known about is cytotoxicity and mechanism of action. Culture of the biopsied endometriomas permitted qualitative cytotoxic assessments by way of comparison with cultured normal uterine endometrial cells treated in vitro with Danazol. The growth characteristics were studied in monolayer and collagen gel cultures. Cytopathology was characterised by light and electron microscopy. Since endometriosis is associated with infertility in women, data from in vitro fertilisation (IVF) were analysed with respect to treatment modalities as compared with cases suffering fallopian occlusion. Danazol reduced pregnancy chances. Two factors may be responsible: (a) altered follicle development resulting in poor oocyte quality (b) reduced nidation because of long-lasting endometrial cytotoxicity. The experimental findings reported here support the latter explanation. Consequently, Danazol therapy should be conditional; patients wishing to achieve pregnancy should preferably receive hormonal therapy.

Human granulosa cells in vitro: characteristics of growth, morphology and influence of some cytokines on steroidogenesis.

Granulosa cells (GCs) were characterised morphologically by light and electron microscopy. The steroidogenic capability of GCs in vitro was estimated by radioimmunoassay (RIA): oestradiol (E2), progesterone (P) and androstenedione (A) secreted into the culture medium were measured. The influence of several culture media and anchorage of the cell either to plastic vessels (monolayer) or to collagen fibrils (in gel) were studied. As the various culture media were assayed with regard to their suitability for IVF, it was found that Ham's F10 is quite satisfactory (in agreement with other observations on embryo cultures). A chemically defined medium BM 86 was found to be inadequate. In addition to the two cell types which are known, a third cell type which can perform efficient aromatisation (E2 production) in vitro is characterised here. The influence of cytokines/growth factors (GF) like insulin-like GF (IGF-1), epidermal GF (EGF), platelet-derived GF (PDGF) and fibroblast GF (FGF) on steroidogenesis was tested either alone or with human chorionic gonadotrophin (hCG). Except for oestradiol (E2) from early GCs, hCG generally stimulated progesterone (P) and E2 secretion. EGF by itself enhanced the secretion of P but not of E2. EGF did not affect hCG stimulation of P, but reduced that of E2. In contrast, in pre-ovulatory GCs IGF-I reduced the stimulatory effect of hCG on both E2 and P. In early GCs IGF-I potentiated hCG stimulation of P. In early GCs, neither hCG nor IGF-I nor a combination of IGF-I with hCG had any effect on E2 production.

Fertilising capacity of human sperms: a simple predictive assay.

Male subfertility is a growing reason for assisted reproduction. A limiting factor in male subfertility is asthenospermia. Motility is a cardinal indication of sperm vitality. Thus prognostic assays are aimed at quantitative determination of progression to assess the fertilising potential. However, a method permitting reliable prognosis of the fertilising capacity has yet to be developed. The assay presented here is the outcome of empirical data based on 590 IVF (in vitro fertilisation) trials. It is essentially a further exploitation of the Swim Up procedure, the selected sperms being maintained in culture under identical conditions employed in IVF. Semi-quantitative daily recordings of linear progression until complete extinction provided an index on vitality which is directly related to the fertilising potential. The findings indicated that a threshold of 50% linear motility after 24 hr culture was required to initiate fertilisation. The fertilising potential was guaranteed when at least 60% linear motility was observed at 24 hr, making the assay a predictive one. Its simplicity is an attractive feature.

90Sr-90Y biokinetics at incorporation determine the radiation burden to bone marrow.

The decay characteristics of 90Sr-90Y ensure that the mother and daughter nuclides exist in radioactive equilibrium, unless they get discriminated on the basis of their chemical properties, as it happens during metabolism. Although bone is the ultimate organ of deposition, the two nuclides arrive at this target organ over different biokinetic pathways. As 90Y is not excreted, it goes through transient deposition in the liver before being secondarily deposited in bone. This leads to a temporary radioactive excess of 90Y in bone. Since the decay energy of 90Y is by a factor of about 4 higher than that of 90Sr, the initial radiation burden to the bone marrow is primarily due to 90Y. This was estimated in rats by implanting LiF thermoluminescence dosimeters (TLD) in the marrow cavity of the femur. By calibrating the TLD against a known source of 90Sr-90Y, the absorbed dose rates and cumulative doses were determined as a function of time after incorporation. Two routes of administration were employed and their influence on the radiation burden is also shown.

Human granulosa cells in vitro: influence of GnRH/GnRH-agonist on steroidogenesis and on IVF outcome.

Steroidogenic activities of the granulosa cells (GCs) from 84 IVF trials were evaluated with respect to a set of ovarian stimulation regimens. Oestradiol (E2) synthesis of the GCs in vitro (obtained at oocyte retrieval) was compared to the maximal serum E2 levels of the same patients at induction of ovulation. Three stimulation regimens were employed: human post-menopausal gonadotrophin (hMG) alone; hMG accompanied by daily doses of a gonadotrophin releasing hormone agonist (GnRH-a); hMG preceded by a single depot application of the GnRH-a. Plots of E2 synthesis in vitro against serum E2 levels indicated that the GnRH-a directly inhibited E2 synthesis in the granulosa cells. This was confirmed in vitro by adding the agonist to the culture medium: both progesterone (P) and E2 syntheses were reduced in the presence of GnRH-a. Despite this drawback, the success of in vitro fertilization (IVF), as gauged by pregnancies achieved, was best for the group which received the GnRH-a as a single depot dose during the previous menstrual cycle, prior to the commence of stimulation. This success is attributed to the lower incidence of cancellations because of premature leuteinizing hormone (LH) surges which happen sometimes during ovarian stimulation. The implications of a direct influence of GnRH-a on E2 synthesis need to be further investigated.