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Biomedical subjects

M Breckwoldt

Publications and source records attributed to M Breckwoldt.

At least 37 records · Page 2Linked to original sources
PubMed1998

Oestradiol production by luteinized human granulosa cells: evidence of the stimulatory action of recombinant human follicle stimulating hormone.

In this study the effect of recombinant human follicle stimulating hormone (rFSH) on oestradiol production by human granulosa-lutein cells was examined in long-term culture, in the presence or absence of androgens. Cells were harvested at the time of follicular aspiration after ovarian hyperstimulation for in-vitro fertilization and cultured for 9 days. Granulosa cells were capable of secreting oestradiol spontaneously even without androgen and gonadotrophin support. Basal oestradiol secretion was relatively high and variable (421.3 +/- 159.3 pg/ml, mean +/- SEM, n = 13) on the first day and decreased gradually to 16.7 +/- 3.1 pg/ml on day 9. Addition of androgens (testosterone or androstenedione) to the incubation medium enhanced dose-dependently basal oestrogen production on days 5, 7 and 9. The androgen/oestrogen conversion rate remained constantly high during the culture, even without rFSH. After pre-incubation for 3 days, addition of rFSH resulted in a dose- and time-dependent increase in granulosa-lutein cell oestrogen production in the absence of exogenous androgens. Testosterone supplementation caused considerably higher basal oestradiol concentrations, however rFSH failed to further stimulate the oestrogen release from granulosa-lutein cells, suggesting that these cells cultured in vitro possess high aromatase activity even without rFSH support.

Androstenedione↗
PubMed1998

Expression of interleukin-6 and interleukin-6 receptors in human granulosa lutein cells.

Cytokines are important regulators of reproductive functions. Significant amounts of interleukin-6 (IL-6) have been detected in the serum and ascites of patients with ovarian hyperstimulation syndrome (OHSS). These findings suggest the involvement of IL-6 as a mediator in the pathogenesis of OHSS. This study was performed to analyse IL-6 and IL-6 receptor (IL-6-R) expression in human granulosa lutein cells (GC). GC were cultured after isolation from follicular fluid. IL-6 concentrations in follicular fluid and serum from individual patients and GC supernatants were measured by enzyme-linked immunosorbent assay. We found detectable concentrations of IL-6 in serum and follicular fluid of all patients. Expression of IL-6 in GC was shown immunocytochemically. IL-6 mRNA was detected in GC by in-situ hybridization. Gene expression for IL-6 and IL-6-R in GC was demonstrated using reverse transcription-polymerase chain reaction. IL-6 significantly inhibited human chorionic gonadotrophin (HCG)-induced progesterone secretion of GC. The results of our study suggest that IL-6 is expressed in HGC and that this cytokine is able to modulate GC function via its specific receptor. This is the first report that describes the precence of IL-6-R in human granulosa lutein cells.

Cells, Cultured↗
PubMed1998

Secretion of vascular endothelial growth factor/vascular permeability factor from human luteinized granulosa cells is human chorionic gonadotrophin dependent.

Vascularization is a prominent event during corpus luteum formation, providing low density lipoproteins for steroid biosynthesis and enabling transport of secreted steroids. The process of vascularization is controlled by specific regulators. Vascular endothelial growth factor (VEGF), otherwise named vascular permeability factor (VPF), induces endothelial cell proliferation as well as angiogenesis in vivo and increases capillary permeability. Here we report the expression of VEGF/VPF mRNA by cultured human luteinized granulosa cells (GC) for at least 10 days. Without HCG VEGF/VPF expression declined after day 4 and by day 10 was reduced to approximately 30% of the value at day 4. However, after culture in the presence of 1 U/ml human chorionic gonadotrophin (HCG), expression of VEGF/VPF mRNA by GC was four times greater than control experiments by day 10, and increased 100% from day 4 to day 10. Simultaneously, HCG supplementation increased VEGF/VPF secretion by GC. Medium VEGF/VPF on day 3 was 13 pM without and 11 pM with HCG. Medium VEGF/VPF on day 10 was 6 pM without HCG and 29 pM with HCG. These results suggest that vascularization of the corpus luteum is induced by HCG-mediated effects of VEGF/VPF.

Adult↗
PubMed1998

Fetal cerebral AV-malformation and cardiomegaly, diagnostic and therapeutic problems.

Intracerebral aneurysms are rare. However they are potentially life-threatening. Today by means of ultrasound investigations these malformations can occasionally be identified prenatally. In these cases questions of intrauterine therapy, mode and time of delivery and postnatal treatment have to be discussed with the parents. We describe two cases with prenatal diagnosis of intracerebral arteriovenous malformations, diagnostic workup, therapeutic options and fetal outcome.

Adult↗
PubMed1998

Vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF) production by luteinized human granulosa cells in vitro; a paracrine signal in corpus luteum formation.

Vascularization is a prerequisite for corpus luteum formation. Angiogenesis is thought to be regulated by vascular growth factors. Vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF) specifically induces endothelial cell proliferation as well as angiogenesis and increases capillary permeability. Recently, VEGF/VPF-mRNA expression was demonstrated in luteinized human granulosa cells (GC) in vitro. In addition, the production of VEGF/VPF by human granulosa can be demonstrated immunocytochemically. VEGF/VPF is thought to mediate its effects through specific cell surface receptors. So far, two VEGF/VPF-receptors (VEGF/VPF-R) have been identified (KDR, and flt-1). A third receptor (flt-4) is highly correlated to KDR and flt-1, but the true ligand for this receptor is still unknown. The appearance of all three receptors is more or less restricted to endothelial cells. To clarify whether VEGF/VPF acts in an auto- or paracrine fashion in human luteinized GC, mRNA was scrutinized for specific expression of the three receptors by Northern blot technique. No specific VEGF/VPF-R or flt-4 transcripts were detectable, indicating that VEGF/VPF is a genuine paracrine growth factor from human luteinized GC directed to endothelial cells.

Adult↗
PubMed1998

Estrogen replacement therapy and cardiovascular protection: lipid mechanisms are the tip of an iceberg.

Cardiovascular disease remains a major cause of mortality among postmenopausal women. After menopause, atherogenesis is promoted by a number of metabolic and vascular changes. A multitude of observational clinical studies have come to the conclusion that estrogen replacement therapy (ERT) reduces cardiovascular risk by approximately 50% and that estrogen's favorable effects on the lipid profile can explain only 25-50% of the overall observed reduction. Estrogens are now known to have potent anti-atherogenic properties through lipid and non-lipid mechanisms; both will be highlighted in view of the recent literature. Estrogens induce favorable changes on lipids and lipoproteins, partly by increasing HDL-cholesterol and decreasing both LDL-cholesterol and lipoprotein (a). Non-lipid mechanisms of estrogen action include decreasing insulin resistance, serum fibrinogen, factor VII and plasminogen activator inhibitor-1 (PAI-1). Moreover, estrogens maintain endothelial cell integrity, decrease expression of adhesion molecules, lower systemic blood pressure, promote vasodilatation, decrease platelet aggregability, inhibit vascular smooth muscle cell proliferation, possess potent antioxidant and calcium antagonist activities, inhibit adrenergic responses and downregulate platelet and monocyte reactivity. Also mentioned are recent reports linking estrogen to the renin-angiotensin system, relaxin, serotonin and homocysteine. What was once thought of as a simple action is now being increasingly appreciated as a complex, multifaceted mechanism, which serves to prove that estrogen is a powerful cardiovascular agent.

Aged↗
PubMed1997

A surprisingly ameliorating effect of high doses of estradiol in primary osteomyelofibrosis: a case report.

OBJECTIVES: To report a case of a postmenopausal woman with primary (idiopathic) osteomyelofibrosis who showed a considerable improvement under the effect of high doses of estradiol given for the control of severe intractable menopausal symptoms. METHODS: This study was carried out by a case report. RESULTS: Astonishingly, under the effect of high doses of estradiol, both clinical and laboratory indices of the disease were not only kept stable but also showed a noticeable improvement. Hemoglobin increased from a value of 8.4 gm/dl in 1989 to 10.7 gm/dl in 1996. Blood transfusion was no longer necessary, the patient had had no infections whatsoever and was only afraid of not being allowed to continue using these high estrogen doses, which seemed indispensable and central to her well-being. CONCLUSIONS: High doses of estrogens could possibly be given the credit for ameliorating the natural sinister course of primary osteomyelofibrosis.

Climacteric↗
PubMed1997

Intrauterine insemination for treatment of male infertility.

Intrauterine inseminations (IUI) have been performed since the beginning of this century for treatment of infertility. Despite its widespread use the clinical value of this technique remains unclear. Today, indications for IUI include male factor, cervical factor, immunological and unexplained infertility and infertility due to ejaculatory disorders. IUI is superior to intravaginal (IVI) or intracervical insemination (ICI). Before insemination, semen has to be processed using one of the established sperm preparation techniques. Different techniques seem to be equally effective in preparing a highly concentrated sperm fraction with progressively motile, morphologically normal sperm. Ovarian stimulation further improves pregnancy rates achieved by insemination. Human menopausal gonadotropin (HMG) stimulation seems to be superior to clomiphene citrate stimulation. Among other factors, timing and number of inseminations are crucial when influencing the outcome of IUI treatment.

Female↗
PubMed1996

PGE2 and PGF2 alpha release by human peritoneal macrophages in endometriosis.

OBJECTIVE: To test for differences in the amount and activity of peritoneal macrophages present in the peritoneal fluid of women with, and without endometriosis using prostaglandin release by macrophages in culture as a marker. PATIENTS: Women of reproductive age undergoing laparoscopy for infertility or chronic pelvic pain with postoperative diagnosis of endometriosis and women undergoing laparoscopy for sterilization. METHODS: Peritoneal fluid was aspirated during laparascopy, volume was recorded, macrophages were isolated via a Ficoll Paque gradient and kept in primary culture. PGE2 and PGF2 alpha release of the cells were measured before and after stimulation with zymosan. RESULTS: Women with endometriosis had significantly more peritoneal macrophages than controls. Peritoneal macrophages of women with endometriosis released significantly more PGE2 than those of the control group: 8.4 +/- 2.0 versus 1.4 +/- 0.4 ng/ml/10(6) cells (mean +/- SEM, p = 0.0005) and PGF2 alpha: 10 +/- 4.3 (endometriosis) versus 1.8 +/- 0.4 (control) ng/ml/10(6) cells (mean +/- SEM, p = 0.045). CONCLUSION: There is a significant increase in the amount of prostaglandins released by peritoneal macrophages from women with endometriosis. These prostaglandins might alter uterine and tubal contractility, thereby affecting fertility.

6-Ketoprostaglandin F1 alpha↗
PubMed1996

Arachidonate metabolism in human placenta, fetal membranes, decidua and myometrium: lipoxygenase and cytochrome P450 metabolites as main products in HPLC profiles.

Eicosanoids play a key role in pregnancy maintenance and parturition. We investigated the metabolism of arachidonic acid (AA) in short-term tissue cultures of placenta, fetal membranes, decidua and myometrium. Tissues were obtained from caesarean sections before the onset of labour after uncomplicated pregnancies. The released metabolites were analysed by high performance liquid chromatography (HPLC) and specific immunoassays. In radiotracer experiments tissues were labelled with [3H]-AA and metabolites released after incubation with calcium ionophore A23187 were profiled by HPLC. Decidua was more active in metabolizing AA (turnover 34 per cent) than myometrium (28 per cent), placenta (21 per cent) and fetal membranes (17 per cent). Main product in placenta, decidua and myometrium was 12-hydroxyeicosatetraeinoic (12-HETE) (decidua: 19 per cent of released radioactivity, myometrium 14 per cent, placenta 7 per cent). Fetal membranes formed 5-HETE as main product. Another major metabolite in placenta, fetal membranes and decidua was characterized by HPLC as 5(6)-epoxyeicosatrienoic acid. Only myometrium released appreciable amounts of prostaglandins in form of 6-keto-prostaglandin F1 alpha. In non-radioactive experiments formation of eicosanoids from endogenous AA was investigated by HPLC (fluorescence- and UV-detection) and immunoassays. These experiments confirmed the high production of 12-HETE and the low formation of prostaglandins. Our results suggest that the biological role of AA-metabolites, other than prostaglandins, have as yet been underestimated.

Arachidonic Acid↗
PubMed1996

[Changes in serotonin metabolism in pre-eclampsia].

Several complications of pregnancy have been reported to be associated with alterations of serotonin (5-HT). This study describes the changes in 5-HT metabolism in patients with preeclampsia. Our examination findings should explain if there are elevated 5-HT and 5-HIAA concentrations in urine and serum of women with preeclampsia. On the other hand it should be proved if the observed chances are due to a decreased kidney function and if there is an important prognostic factor to detect asymptomatic preeclamptic patients. 5-HT and its main metabolite 5-hydroxy-indol-acetic acid (5-HIAA) was evaluated in serum and urine of 24 pregnant women with preeclampsia and of 27 pregnant women without preeclampsia in the last month of pregnancy, within 24 hours after delivery and at the fourth day post partum. Besides 5-HIAA was ascertained in 24-h urine from the 24th week of pregnancy until after delivery. 5-HIAA excretion increased continuously during pregnancy independently of whether the patients developed preeclampsia. A significant less increase and lower concentration of 5-HIAA pre and post partum were observed in preeclamptic patients when compared to non-preeclamptic patients. We noticed a remarkably lower 5-HIAA excretion and a higher concentration of 5-HT in women with preeclampsia. Preeclamptic patients demonstrate a lower decrease of 5-HIAA and a significantly greater increase of 5-HT than women without preeclampsia. These results could be explained by a decreased metabolism of 5-HT due to the placental MAO. The changes observed in our study are not due to a decreased kidney function because creatinine concentrations in women with and without preeclampsia were comparable. Our results indicate that 5-HIAA-/creatinine ratio might be an important prognostic factor.

Adult↗
PubMed1996

Expression of Ad4-BP/cytochrome P450 side chain cleavage enzyme and induction of cell death in long-term cultures of human granulosa cells.

Freshly isolated granulosa cells obtained from women undergoing in-vitro fertilization (IVF) become refractory to further gonadotrophin stimulation in culture due to their previous hormonal treatment. However, when precultured for 7 days in gonadotrophin-free medium they regain their response to both human chorionic gonadotrophin (HCG) and follicle stimulating hormone (FSH) with a 10-fold and 5-fold increase in progesterone production respectively, within an additional 7 days of culture. Forskolin, a direct activator of adenylate cyclase, increased progesterone levels 12-fold compared with non-stimulated cultures. Oestradiol formation was also significantly elevated (P < 0.005) following 48 h stimulation with luteinizing hormone (LH), FSH or forskolin. Intracellular cAMP levels rose 1.5-fold, 10-fold and 15-fold after 1 h of FSH, HCG or forskolin treatment. Expression of both cytochrome P450 side chain cleavage enzyme (SCC) and the steroidogenic transcription factor SF1/Ad4BP could be demonstrated by Western blotting. However, elevation of P450 SCC alone was evident following FSH and HCG stimulation. In the presence of serum, the ultrastructure of these cultured cells displayed numerous lipid droplets and well-developed mitochondria, characteristic of highly steroidogenic cells. The proportion of apoptotic nuclei in these cultures was < 30%. Removal of the serum increased apoptotic incidence to 40%, whereas addition of FSH prevented cell death significantly (P < 0.01). HCG and forskolin increased apoptosis to approximately 50%, while treatment with 8Br-cAMP led to 80% cell death. Our data suggest that, after prolonged culture, human granulosa cells can regain cAMP and steroidogenic response to gonadotrophin stimulation. Moreover, our experiments indicate that apoptosis and steroidogenesis can coexist in the same cell population while the interrelationship between these processes can be determined by the intracellular levels of cAMP.

Apoptosis↗
PubMed1996

Non-competitive anti-oestrogenic actions of progesterone antagonists in primate endometrium: enhancement of oestrogen and progesterone receptors with blockade of post-receptor proliferative mechanisms.

Previous studies have shown that the progesterone antagonists (antiprogestins) inhibit oestrogen-dependent endometrial proliferation in ovariectomized monkeys, without having affinity to the oestrogen receptor (ER). This study was designed to investigate the effect of the antiprogestins mifepristone (RU 486) and onapristone (ZK 98,299), on the concentration of ER and progesterone receptor (PR) in the endometrium of long-term ovariectomized cynomolgus monkeys (Macaca fascicularis). In untreated monkeys, tissue preparations bound in total 228 +/- 68 pmol [3H]-oestradiol/g protein (ER), and 119 +/- 42 pmol [3H]-R5020/g protein (PR). These values were not significantly different from the total binding capacities of tissues from monkeys treated with RU 486 alone or primates treated with oestradiol plus progesterone. Treatment with oestradiol alone almost doubled the ER and PR concentrations. Combined treatment with oestradiol and RU 486 enhanced the ER and PR concentrations in a dose-dependent manner: 1 mg/kg body weight (bw) RU 486/kg increased both ER and PR contents about 3-fold. The dose of 5mg/kg bw RU 486 or onapristone increased the ER and PR concentrations almost 6- and 5-fold respectively, compared with the oestradiol-treated controls. Our results demonstrate that RU 486 and onapristone increased the endometrial ER and PR concentrations far beyond the physiological level in ovariectomized, oestradiol-treated monkeys. Whether the over-expression of ER and PR in the presence of antiprogestins is causally related to the antiproliferative impact of antiprogestins in the endometrium (non-competitive anti-oestrogenic effects) or is an independent action in unknown.

Animals↗
PubMed1995

Benefits and risks of hormone replacement therapy (HRT).

In western countries more than 30% of the female population are postmenopausal. Approximately 30% of postmenopausal women suffer from clinical symptoms of the climacteric such as vasomotor symptoms, associated with hot flushes, night sweat, insomnia and depressive mood. Sufficient hormonal replacement therapy (HRT) will abolish specific menopausal symptoms in over 90% of patients, unspecific symptoms such as headache respond to placebo and HRT equally well. The question of cancer risk related to HRT will be addressed in this review. In combination with progestins, estrogens are obviously protective regarding ovarian and endometrial cancer. The association between HRT and breast cancer risk is presently unclear. Epidemiological data available so far do not provide compelling evidence as to a cause and effect relationship between HRT and breast cancer risk. There seems to be an overall trend towards a slightly increased risk with increasing duration of HRT use. Guidelines for HRT use in women with a history of endometrial and breast cancer are provided in this article.

Breast Neoplasms↗
PubMed1995

[Effect of pregnancy and labor on serotonin metabolism].

Several complications of pregnancy have been reported to be associated with alterations of serotonin (5-hydroxytryptamine; 5-HT) metabolism. Reported data regarding changes of 5-HT metabolism in pregnancy are partially contradictory. The presented study tries to describe pregnancy-associated changes in 5-HT metabolism. Urine and blood samples were taken from 20 pregnant women 4 weeks before, within 24 hours and on the 4th day following delivery. 17 non-pregnant age-matched women served as controls. 5-HT and its main metabolite 5-hydroxyindoleacetic acid (5-HIAA) were analysed. We observed a continuously increasing production and excretion of unbound 5-HT and 5-HIAA during pregnancy. Four days after delivery 5-HT production returned to baseline levels, while excretion remained elevated. 5-HIAA excretion increased in pregnancy and return to baseline levels on the day following delivery. Increased 5-HT metabolism and excretion results in a decreased 5-HT serum concentration despite increased 5-HT production during pregnancy. Our results help to understand the contradictory observations of elevated 5-HT production on the one hand and decreased 5-HT activity during pregnancy on the other.

Adult↗
PubMed1995

[Psychological consultation at a gynecologic clinic--a luxury or a necessity?].

The necessity for an integrated psychological care is proven by the example of the Psychological Ambulance in the University of Freiburg Women's Hospital. In 1993 387 out- or inpatients contacted the psychologist, mainly out of their own initiative. 819 consultations, each lasting for at least 45 minutes, were registered. Parameters influencing acceptance and implementation were as follows: formal qualification as well as medical and psychological competence of the staff; cooperation with the hospital physicians and other institutions providing psychosocial care. We found that further important is the integration within the hospital facilitated by the consultation-model plus the longterm perspective of the ambulance and its staff. Additional promotion of acceptance was generated by the informal recommendations among patients.

Adaptation, Psychological↗