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Biomedical subjects

B Imthurn

Publications and source records attributed to B Imthurn.

At least 19 recordsLinked to original sources
PubMed2006

Family stability during childhood and the risk to develop hypertensive diseases in pregnancy.

BACKGROUND: Parental care giving, divorce and death are associated with physical health as an adult. AIM: To investigate whether the structure of the nuclear family during childhood shows any correlation with the development of hypertensive diseases in pregnancy as an adult. STUDY DESIGN: Self-administered questionnaires were sent to 2600 women with hypertensive diseases in pregnancy and to 1484 controls. SUBJECTS: After confirmation of the diagnosis data from 842 patients and 623 control women were evaluated. OUTCOME MEASURES: Type, number and involvement of different caregivers, parental separation, parental death. RESULTS: In both groups parental separation and parental death were found equally often. In all age groups during childhood fathers were involved significantly less often in care giving when women with hypertensive disorders in pregnancy were compared to control women (1st-3rd year 23.4%/17%, <0.0001; 4th-10th year 25.7%/19.3%, <0.0001; 11th-18th year 30.1%/23.9%, <0.0001). The total number of caregivers involved was significantly higher in patients. CONCLUSIONS: The quality of parental care giving, i.e. the involvement of fathers and the total number of caregivers correlate with the risk to develop HDP. Further research is needed to specify underlying mechanisms and the relevant factors of the parent-child relationship.

Adult↗
PubMed2001

Increased incidence of numerical chromosome abnormalities in spermatozoa injected into human oocytes by ICSI.

The potential risk of transmitting chromosomally abnormal spermatozoa from infertile males into oocytes through intracytoplasmic sperm injection (ICSI) has prompted us to investigate the male pronuclei of tripronuclear zygotes (3PN) obtained after ICSI. To specify the type of anomalies, we used triple colour fluorescent in-situ hybridization (FISH) with three specific probes for chromosomes X, Y and 18. From a total of 163 paternal complements of ICSI-3PN zygotes, 90 (55.2%) had Y-chromosome signals. Eighty-three of these were normal, four had the disomy XY and three were diploid. In the remaining 73 ICSI-3PN zygotes without Y-chromosome signals, the origin of paternal pronuclei was extrapolated through chromosome constitution of the first polar body. Five anomalies were found in this group of zygotes, giving a total rate of numerical chromosome aberrations for fertilizing spermatozoa of 7.4%. In contrast to ICSI, only two disomies (1.5%) were found in the control group of IVF-3PN zygotes. Compared with the incidence of chromosome anomalies between paternal-derived pronuclei of ICSI- and IVF-3PN zygotes, the difference was statistically significant (P < 0.025). This study provides the first direct evidence of a higher incidence of numerical chromosome anomalies in sperm-fertilized human oocytes after ICSI.

Chromosome Aberrations↗
PubMed2001

Estradiol metabolites inhibit endothelin synthesis by an estrogen receptor-independent mechanism.

Estradiol inhibits endothelin-1 synthesis, an effect that may contribute to the cardiovascular protective effects of estradiol. Recent findings that estradiol inhibits neointima formation in mice lacking estrogen receptors suggests that the cardiovascular protective effects of estradiol may be mediated by means of an estrogen receptor-independent mechanism. Because 2-hydroxyestradiol and 2-methoxyestradiol, metabolites of estradiol with little/no affinity for estrogen receptors, are more potent than estradiol in inhibiting vascular smooth muscle cell growth, we investigated whether these metabolites also inhibit endothelin-1 synthesis by means of an receptor-independent mechanism. Treatment of porcine coronary artery endothelial cells for 4 to 24 hours with 0.001 to 1 micromol/L of estradiol, 2-hydroxyestradiol, or 2-methoxyestradiol concentration-dependently inhibited basal as well as serum-induced (2.5%), TNFalpha-induced (10 ng/mL), angiotensin II-induced (100 nmol/L), and thrombin-induced (4 U/mL) endothelin-1 synthesis. Estradiol, 2-hydroxyestradiol, and 2-methoxyestradiol also inhibited serum-induced mitogen-activated protein kinase activity. As compared with estradiol, its metabolites were more potent in inhibiting endothelin-1 secretion and mitogen activated protein kinase activity. The inhibitory effects of 2-hydroxyestradiol and 2-methoxyestradiol on endothelin-1 release and mitogen-activated protein kinase activity were not blocked by ICI182780 (50 micromol/L), an estrogen receptor antagonist. Our findings indicate that the estradiol metabolites 2-hydroxyestradiol and 2-methoxyestradiol potently inhibit endothelin-1 synthesis by means of an estrogen receptor-independent mechanism. This effect of estradiol metabolites may be mediated by inhibition of mitogen activated protein kinase activity and may contribute to the cardioprotective effects of estradiol.

2-Methoxyestradiol↗
PubMed2000

Gonadotrophin administration can benefit ovarian tissue grafted to the body wall: implications for human ovarian grafting.

Ovarian grafting provides a strategy for clinical infertility treatment and is starting to be used in conjunction with ovarian tissue storage for patients at risk of early ovarian failure. As patients are starting to return for their frozen stored tissue we need to ascertain how to maximise follicle survival when this tissue is grafted back to the patient. For research purposes ovarian tissue is commonly grafted to the kidney capsule as the rich capillary bed at this site favours rapid graft revascularization. This is however not an ideal site for natural conceptions or for the harvest of mature oocytes for in vitro fertilization. While oocytes would be relatively easy to recover from grafts on the abdominal wall or subcutaneous tissue graft revascularization at these sites is slower and evidence indicates that fewer follicles survive. As gonadotropins can upregulate angiogenic growth factors in the ovary this study was designed to test whether the administration of exogenous gonadotropins would increase the number of surviving follicles in grafts placed at less vascularised sites. We showed that exogenous gonadotrophins, given to either the donor or the recipient, could increase the number of developing follicles but the magnitude of this effect was influenced by the timing of the injections relative to the time of grafting.

Abdominal Muscles↗
PubMed2000

[Climacteric syndrome].

The most frequent symptoms of the climacteric syndrome are hot flushes. Although usually they disappear after a few years, hot flushes persist for five or more years in a quarter of the affected women. Aetiology and pathomechanism are not clear. Apart from oestrogen deficiency other diseases should be evaluated as potential causes of hot flushes such as psychosomatic disorders, hyperthyroidism and a neoplasm. The treatment of the first choice is an oestrogen replacement therapy. By assaying a single serum sample for oestradiol an oestrogen replacement therapy can be monitored reliably only in the case of transdermal application.

Administration, Cutaneous↗
PubMed2000

The effect of the menstrual cycle and of ethinylestradiol on nitric oxide, endothelin-1 and homocysteine plasma levels.

The use of the estrogen ethinylestradiol is associated with an increased cardiovascular risk. It is not known whether this might be caused by an influence of ethinylestradiol on endothelium-derived factors or on the cardiovascular risk factor homocysteine. Our aim was to evaluate whether a short-term treatment with ethinylestradiol results in changes of nitric oxide (NO), endothelin-1 and homocysteine. Participants were ten healthy women with regular menstrual cycles. NO, homocysteine, endothelin-1, estradiol and progesterone were measured during one cycle and before and after treatment with ethinylestradiol at 50 microg/day. Homocysteine and NO did not change significantly during the menstrual cycle or after treatment. However, endothelin-1 levels decreased during the cycle (from 3.89 ng/l to 2.93 ng/l p < 0.05) and after ethinylestradiol (from 2.94 ng/l to 2.26 ng/l p<0.03). Analysis of the pretreatment data showed a positive correlation between homocysteine and NO and between NO and endothelin-1. Treatment with ethinylestradiol caused a shift in the balance between NO and endothelin-1 in the direction of vasodilatation. This finding is one factor concerning the effects of ethinylestradiol on the vascular system but does not explain the cardiovascular risk of this substance.

Adult↗
PubMed2000

Clinically used estrogens differentially inhibit human aortic smooth muscle cell growth and mitogen-activated protein kinase activity.

Some estrogenic compounds modify vascular smooth muscle cell (SMC) biology; however, whether such effects are mediated in part by estrogen receptors is unknown. The purpose of this study was to evaluate whether the actions of clinically used estrogens on human aortic SMC biology are mediated by estrogen receptors. We examined the effects of various clinically used estrogens in the presence and absence of ICI 182,780, an estrogen receptor antagonist, on cultured human aortic SMC DNA synthesis ([(3)H]thymidine incorporation), cellular proliferation (cell counting), cell migration (modified Boyden chamber), collagen synthesis ([(3)H]proline incorporation), and mitogen-activated protein kinase activity. FCS-induced DNA synthesis, cell proliferation, collagen synthesis, platelet-derived growth factor-induced SMC migration, and mitogen-activated protein kinase activity were significantly inhibited by physiological (10(-9) mol/L) concentrations of 17beta-estradiol and low concentrations (10(-8) to 10(-7) mol/L) of 17beta-estradiol, estradiol valerate, estradiol cypionate, and estradiol benzoate but not by estrone, estriol, 17alpha-estradiol, or estrone sulfate. The inhibitory effects of 17beta-estradiol and other inhibitory estrogens were completely reversed by 100 micromol/L ICI 182,780, and the rank-order potency of various estrogens to inhibit SMC biology matched their rank-order affinity for estrogen receptors. The inhibitory effects of estrogens on SMC biology are in part receptor-mediated. Because the cardioprotective effects of hormone replacement therapy are most likely mediated by modification of SMC biology, whether hormone replacement therapy protects a given postmenopausal woman against cardiovascular disease will depend partially on the affinity of the estrogen for estrogen receptors in vascular SMCs.

Aorta↗
PubMed1999

Phytoestrogens inhibit growth and MAP kinase activity in human aortic smooth muscle cells.

-Estrogens are known to induce cardioprotective effects by inhibiting smooth muscle cell (SMC) growth and neointima formation. However, the use of estrogens as cardioprotective agents is limited by carcinogenic effects in women and feminizing effects in men. If noncarcinogenic and nonfeminizing estrogenlike compounds, such as natural phytoestrogens, afford cardioprotection, this would provide a safe method for prevention of cardiovascular disease in both men and women. Therefore, we evaluated and compared in human aortic SMCs the effects of phytoestrogens (formononetin, genistein, biochanin A, daidzein, and equol) on 2.5% fetal calf serum-induced proliferation (3H-thymidine incorporation and cell number), collagen synthesis (3H-proline incorporation), and total protein synthesis (3H-leucine incorporation) and on PDGF-BB (25 ng/mL)-induced migration (modified Boydens chambers). Moreover, the effects of phytoestrogens on PDGF-BB (25 ng/mL)-induced mitogen-activated protein kinase (MAP kinase) activity in SMCs was also studied. Phytoestrogens inhibited proliferation, collagen and total protein synthesis, migration, and MAP kinase activity in a concentration-dependent manner and in the following order of potency: biochanin A>genistein>equol>daidzein>formononetin. In conclusion, our studies provide the first evidence that in human aortic SMCs phytoestrogens inhibit mitogen-induced proliferation, migration and extracellular matrix synthesis and inhibit/downregulate MAP kinase activity. Thus, phytoestrogens may confer protective effects on the cardiovascular system by inhibiting vascular remodeling and neointima formation and may be clinically useful as a safer substitute for feminizing estrogens in preventing cardiovascular disease in both women and men.

Adult↗
PubMed1998

Impairment of the developmental potential of frozen-thawed human zygotes obtained after intracytoplasmic sperm injection.

OBJECTIVE: To evaluate the effects of cryopreservation on the survival, cleavage, and morphology of embryos and on the implantation and embryonic loss rates of human zygotes obtained after ICSI compared with frozen-thawed zygotes obtained after traditional IVF. A further objective was to evaluate the same parameters in nonfrozen sibling ICSI and IVF zygotes and to compare them with corresponding frozen-thawed zygotes. DESIGN: Open, retrospective, comparative study. SETTING: University-associated assisted reproductive program. PATIENT(S): Couples with severe male factor infertility and couples undergoing IVF during the same period. INTERVENTION(S): A cohort of 408 ICSI zygotes and 299 IVF zygotes was frozen in 1,2 propanediol and sucrose using a slow-freezing protocol. Both groups of zygotes were frozen at approximately the same time after microassisted or conventional insemination. One hundred and eighty-seven ICSI and 110 IVF frozen zygotes were rapidly thawed during 44 ICSI cycles and 24 IVF cycles. Zygotes that appeared to have survived were cultured for 24 hours, and most of these embryos that were morphologically normal were transferred into patients. MAIN OUTCOME MEASURE(S): Survival rate (morphologically intact after thawing), cleavage rate and morphology of embryos, implantation rate, and the incidence of embryonic losses. RESULT(S): Except for survival rates, for which both ICSI and IVF frozen-thawed zygotes showed similar and relatively high values (87.7% and 89.1%), the outcomes of other parameters evaluated were significantly different. Thus, from a total of 128 ICSI and 68 IVF embryos transferred, 14 (10.9%) and 17 (25.0%) implanted in 44 ICSI and 24 IVF frozen-thawed cycles, respectively. This difference in implantation corresponded with the rate of cleavage and morphology of the replaced embryos; the embryos that developed from frozen-thawed IVF zygotes cleaved faster and were more regular compared to the frozen-thawed ICSI zygotes. The embryonic loss rate was 57.1% for cryopreserved ICSI zygotes and 11.8% for IVF zygotes. On the other hand, no difference in cleavage pattern, embryo morphology, implantation, and embryonic loss rates was found between nonfrozen sibling ICSI and IVF zygotes. CONCLUSION(S): The zygotes arising from ICSI cycles survived cryopreservation at a rate similar to IVF zygotes, but their ability to implant and develop further was probably affected by the cryopreservation procedure. The timing of zygote freezing was considered to be the principal reason for the lower developmental potential of frozen-thawed ICSI zygotes in the present study.

Adult↗
PubMed1997

[Pathogenesis and diagnosis of androgenetic manifestations].

The endrocrinologic evaluation of androgenetic phenomena is complex and difficult. The targeted use of diverse hormone determinations and functional tests, of vaginal sonography and other imaging measures as well as selective catheterization of adrenal and ovarial veins in exceptional cases, however, permit efficient and precise diagnoses.

Acne Vulgaris↗
PubMed1997

Differential effects of hormone-replacement therapy on endogenous nitric oxide (nitrite/nitrate) levels in postmenopausal women substituted with 17 beta-estradiol valerate and cyproterone acetate or medroxyprogesterone acetate.

Increased incidence of cardiovascular disease in postmenopausal women (PMW) is accompanied by ovarian dysfunction; hormone replacement therapy (HRT) can have cardioprotective effects. Because hypertension and atherosclerosis are associated with impaired release of endothelium-derived nitric oxide (NO) and increased levels of low-density lipoproteins (LDL), we investigated whether HRT augments NO release, and whether these increases are accompanied by a decrease in LDL levels in PMW. We determined serum nitrite/ nitrate (NO2-/NO3-) and LDL levels at baseline (before initiation of HRT) and during the 6th and 12th months of the study. The PMW (n = 26) received continuous oral administration of estradiol valerate (Progynova, 2 mg daily) for 21 days supplemented with either oral cyproterone acetate (CPA; 1 mg; n = 11) or medroxyprogesterone acetate (MPA; 5 mg; n = 15) on days 12-21 of each treatment cycle. Blood samples in the PMW receiving HRT were collected at times while the subjects were taking estradiol valerate alone and estradiol valerate plus CPA or MPA. Compared with the samples collected at baseline, serum NO2-/NO3- levels increased significantly from 20.1 +/- 1.58 mumol/L at baseline to 30 +/- 3.7 mumol/L (P < 0.01) in samples collected after 12 months of HRT while the PMW were not taking progestins (CPA or MPA), and to 25.4 +/- 2 mumol/L (P < 0.05) when all the samples, regardless of the treatment with CPA or MPA, were included in the analysis. Moreover, > 30% increase in serum NO2-/NO3- levels were observed only in 13 (responders) out of 26 PMW substituted with estradiol valerate, suggesting that estradiol may improve endogenous NO synthesis in a differential fashion. Compared with baseline, no significant increases in serum NO2-/NO3- were observed in samples collected while the estradiol-treated responders were taking either CPA or MPA. In contrast to NO2-/NO3- serum LDL levels were significantly reduced in samples collected after 12 months of HRT (P < 0.05 vs. baseline). Furthermore, levels of NO2-/NO3 showed a significant negative correlation with the levels of LDL (r2 = 0.17; P < 0.05) in the responders but not in nonresponders. These results indicate that oral administration of estradiol valerate in PMW for HRT increases circulating NO levels, an effect that may contribute to the cardioprotective effects of HRT in PMW. In addition, our data suggests but does not prove that concomitant administration of a progestin may attenuate the beneficial effects of estrogen replacement therapy with regard to NO release. Finally, our data provides evidence for the existence of responders and nonresponders to postmenopausal estrogen treatment with respect to improvement of endogenous NO levels, suggesting that a significant number, but not all, of the hormonally substituted PMW profit fully from the beneficial properties of a HRT.

Estradiol↗
PubMed1997

Catamenial hemoptysis. Diagnosis with MRI.

Thoracic endometriosis is a rare disorder. We report a case of a 26-year-old woman with a 4-year history of catamenial hemoptysis due to thoracic endometriosis which was diagnosed by MRI and treated successfully by means of video-assisted thoracoscopic wedge-resection of the solitary pulmonary lesion. Medical therapy with hormones was not necessary. There is no evidence of recurrence 10 months after the operation. This case demonstrates that MRI of the chest may be considered for the diagnostic work-up of patients with catamenial hemoptysis. It also shows that wedge-resection of pulmonary endometriosis foci by means of video-assisted thoracoscopy-an approach that has not been described in the literature thus far-is an effective therapy in localized peripheral pulmonary parenchymal endometriosis.

Adult↗
PubMed1996

Effect of a programmed short-term stimulation protocol on the replacement of cryopreserved embryos.

PURPOSE: Through problems in the management of embryo thawings and transfers, we investigated in a comparative study the use of the natural cycle and of a programmed short-term stimulation protocol as preparation method for the replacement of cryopreserved embryos. To date, 117 embryos have been thawed, and 60 (51%) survived with > or = 50% intact blastomeres. METHODS: In 31 cases, replacement of the frozen-thawed embryos was planned in the natural cycle (group A) and in nine cases in the stimulated cycle (group B). In group A, 16 replacements could be performed (cancellation rate 48%). Six transfers took place on weekends (37%). Two clinical pregnancies could be established (13% per replacement). In group B, there were no canceled cycles (p < 0.025). All thawings and transfers could be conducted between Monday and Friday. In one case, the single one frozen embryo was degenerated after thawing. RESULTS: Thus, eight replacements could be performed which resulted in three clinical pregnancies (38% per replacement, n.s.) and one biochemical pregnancy. CONCLUSIONS: Based on our results, we conclude that a programmed short-term protocol not only provides viable embryos with a good cryopreservation potential, but it is also a reliable preparation method for the replacement of frozen-thawed embryos.

Adult↗
PubMed1996

Chromosome analysis of single- and multipronucleated human zygotes proceeded after the intracytoplasmic sperm injection procedure.

PURPOSE: Fertilization of an egg by injection of a single spermatozoon into the cytoplasm has been shown to be an effective procedure to obtain a pregnancy in human in vitro fertilization. This, as one of the most invasive micromanipulation techniques, has generated concern about inducing embryo abnormalities. The objective of this study was to obtain insight into the chromosomal constitution of zygotes proceeded after the intracytoplasmic sperm injection procedure. METHODS: For this purpose the first cleavage division of 33 single- and 16 multipronucleated zygotes proceeded after the intracytoplasmic sperm injection procedure was cytogenetically analyzed. RESULTS: Chromosome spreading permitted adequate karyotyping in 28 (84.8%) single-pronucleated zygotes. Among these, 19 (67.9%) were haploid, 5 (17.9%) hypohaploid (n = 20-22), and 4 (14.3%) hyperhaploid (n = 24-25). The overall rate of aneuploidy found here for single-pronucleated zygotes was 32.1%. In the 23 (82.1%) analyzed single-pronucleated zygotes, besides single mitotic complements, an intact sperm head or sperm nuclei structure has been found, indicating the maternal origin of these chromosomes. CONCLUSIONS: Ten digynic zygotes with three pronuclei and six zygotes with more than three pronuclei were identified after injecting a single spermatozoon, representing 3.2% of all the fertilized oocytes. Aneuploid chromosome complements were found in three of seven tripronuclear zygotes and each one exhibited a hypo-, hyper-, and haploid complement (23,X, 21,X,-A,-B, 25,X, +A,+B; 23,Y, 22,X,-D, 24,X,+D; 23,X, 22,X,-G, 24,X,+G). The absolute difference in the number of chromosomes between each of these two imbalanced corresponding haplotypes was the same and this difference was caused by the chromosomes belonging to the same groups of karyotype. Of the remaining four tripronuclear zygotes, three had triploid and one had diploid numbers of chromosomes. Furthermore, five zygotes having more than three pronuclei at the first cleavage division displayed severely depleted chromosome complements. The majority of imbalanced multipronuclear zygotes was found after delay of the microinjection, suggesting that aging of oocytes might be the reason for their abnormal chromosomal arrangements.

Adult↗
PubMed1996

Identification of nitric oxide synthase in human and bovine oviduct.

Nitric oxide synthase (NOS) is responsible for the biological production of nitric oxide (NO) in several organs. NOS activity has also been localized in the reproductive tract, although direct evidence for its presence in the human or bovine oviduct is still lacking. In the present study, four different techniques were used to identify the presence of NOS activity in human (n = 11) and bovine (n = 9) oviduct: (i) conversion of [3H]-L-arginine to [3H]-L-citrulline; (ii) production of nitrite/nitrate (NO2/NO3; stable NO metabolites); (iii) identification of NADPH-diaphorase activity; and (iv) immunostaining with antiserum to endothelial NOS. Cytosolic extracts from human ampullary segments of the Fallopian tube, obtained from post-partum patients (n = 4), converted [3H]-L-arginine to [3H]-L-citrulline (21.0 +/- 8.8 fmol/mg protein/min). This conversion rate was significantly (P < 0.05) reduced in the presence of either EDTA or N-monomethyl-L-arginine monoacetate (L-NMMA), an inhibitor of NOS activity. When bovine (n = 3) ampullary segments were incubated for 36 h in Hanks' balanced salt solution, the concentration of NO2/NO3 in the medium was increased (P < 0.05) if segments were pretreated with lipopolysaccharide (LPS; an inducer of inducible NOS), but not after treatment with LPS + L-NMMA. Additionally, epithelial cells cultured from ampullary segments showed positive staining both for NADPH-diaphorase activity and with antiserum to endothelial NOS. The results of the present study provide direct evidence for the presence of both the Ca(2+)-dependent constitutive form of NOS, as well as the inducible form of NOS activity in human and bovine oviduct. Since the oviduct plays a key role in the reproductive process, it is possible that the two forms of NOS may be involved in the physiological regulation of oviduct function.

Animals↗
PubMed1996

Nuclear maturity and oocyte morphology after stimulation with highly purified follicle stimulating hormone compared to human menopausal gonadotrophin.

Several studies have shown that high concentrations of luteinizing hormone (LH) in the follicular phase of stimulation can have a negative effect on oocyte quality, pregnancy rate and incidence of miscarriage. The aim of the present study was to examine the effects of highly purified follicle stimulating/hormone (FSH HP) on ovarian stimulation and particularly on nuclear maturity and morphological appearance of the oocyte in intracytoplasmic sperm injection (ICSI) therapy and to compare the results with human menopausal gonadotrophin (HMG) stimulation. For this purpose, 50 patients for ICSI (HMG: 30; FSH HP: 20) and 26 patients for in-vitro fertilization (IVF; HMG: 14, FSH HP: 12) were stimulated with either HMG or FSH HP using a short-term protocol. Patients were divided into the two groups according to the first letter of their family name. No differences were observed among the groups in relation to patient age, duration of stimulation, number of aspirated oocytes or maturity of the oocyte-cumulus complex. After removal of the cumulus-corona cells in the ICSI oocytes, a significantly higher proportion of oocytes in the FSH HP group were nuclear mature (metaphase II) than in the HMG group (FSH HP: 88.8%, HMG: 80.6%; P = 0.009). Furthermore, in the FSH HP group, significantly fewer oocytes with dark cytoplasm were observed (FSH HP: 14.4%, HMG: 22.4%; P = 0.02). Fertilization, cleavage and pregnancy rates (FSH HP 38%, HMG: 34% per retrieval) were comparable in both groups. Based on the results obtained, it can be concluded that the short-term FSH HP treatment protocol synchronizes oocyte maturation better than comparable stimulation with HMG.

Cell Nucleus↗