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Biomedical subjects

Michael Ludwig

Publications and source records attributed to Michael Ludwig.

At least 37 records · Page 2Linked to original sources
PubMed2005

What is the 'ideal' duration of progesterone supplementation before the transfer of cryopreserved-thawed embryos in estrogen/progesterone replacement protocols?

Different studies dealing with the start of progesterone supplementation in assisted reproduction treatment cycles have shown that the problem apparently is the correct timing. We therefore would like to discuss the data on: (i) the start of progesterone replacement in oocyte donation programmes; (ii) the start of progesterone replacement in frozen-thawed hormone-supplemented cycles; (ii) the problem of too early a rise of progesterone in fresh IVF cycles as a model of too early an administration of progesterone; and (iv) the benefit of high progesterone levels on the day of embryo transfer in fresh IVF cycles. From the data reviewed in this paper it seems to be appropriate to start progesterone administration before transfer in oocyte donation programmes as well as transfer of cryopreserved/thawed cells as soon as the endometrium is developed sufficiently (> or =8 mm, trilaminar pattern), and to perform the embryo transfer not before day 3-4 of progesterone treatment, i.e. embryo development on day 2-3. Studies dealing with the influence of too early a rise of progesterone in fresh IVF cycles have shown different results. In fact high progesterone levels seem to reflect a high response but not a lower probability of conception. Furthermore, high progesterone levels on the day of embryo transfer in fresh IVF cycles could lower myometrial contractility and therefore increase implantation rates. Since the experience from oocyte donation programes shows the benefit of a longer preparation time using progesterone, and high progesterone levels seem to have a benefit during embryo transfer, this would suggest extending progesterone administration before transfer. However, we have to find the optimal individual transfer protocol after mock cycles, for example with pinopode detection or other methods applicable in routine IVF programmes. We need more studies to be sure whether reproductive outcome after transfer of cryopreserved-thawed cells in estrogen/progesterone supplement cycles is influenced by the duration of progesterone pretreatment. If this is so, we must look for practicable methods to modify the protocols according to the individual patient, the embryonic developmental stage during transfer and other variables.

Clinical Trials as Topic↗
PubMed2005

Factors influencing response to ovarian stimulation.

Ovarian stimulation is an integral part of assisted reproduction treatments. Ovarian response to gonadotrophin treatment, besides other factors, determines the outcome of treatment, as the number and quality of oocytes retrieved are related to the chance of achieving a pregnancy. A number of factors have been identified that might predict ovarian response, such as age of the patient and antral follicle count. In addition, it has been shown that genetic factors such as the patient's FSH-receptor genotype also determine individual response to FSH treatment. Besides patient-related factors, the choice of drugs for ovarian stimulation plays a significant role. Until recently, biopotency of gonadotrophin preparations was tested by an in-vivo bioassay with an intrinsic variability up to 20%. Due to a superior manufacturing technique, follitropin alpha can now be filled by mass. This allows assessment of FSH with a precise SE-HPLC assay and variability of the FSH content between production lots has now been estimated at 1.6%. Results of recent studies indicate that treatment with follitropin alpha filled by mass results in consistent ovarian response, fewer treatment days and fewer cancelled cycles. This is an important step towards further minimizing drug-related variability of ovarian response to FSH treatment.

Epidemiologic Factors↗
PubMed2005

The process of decision making in reproductive medicine.

The decision-making process regarding the optimal infertility treatment strategy is influenced by several factors. In addition to the underlying cause of infertility, the process of decision making is also influenced by other factors. These factors are mainly (1) the duration of infertility, (2) patient's age, and (3) the number of previously performed treatment cycles of intrauterine insemination (IUI) or in vitro fertilization (IVF). The duration of infertility influences diagnostic steps as well as therapeutic options. With an infertility of at least 5 years the benefit of intrauterine insemination is limited and couples should be counseled to go forward with IVF. Patients age >or= 40 years should be treated with IVF, whereas patients age >or= 43 years should be counseled about their very limited chance to conceive even through IVF. The number of insemination cycles should be limited to four. Couples who have undergone at least six IVF cycles should be counseled to discontinue therapy. The treatment program should be as individualized as possible, with individual counseling that is adapted after each single treatment cycle.

Decision Making↗
PubMed2005

Risk during pregnancy and birth after assisted reproductive technologies: an integral view of the problem.

Pregnancy and obstetric outcome are the final steps in infertility treatment. Additional data from recent studies demonstrate an increased risk for pregnancy course and obstetric outcome. These risks include an increased risk for intrauterine growth retardation, preeclampsia, and premature birth. Children born after in vitro fertilization and intracytoplasmic sperm injection (ICSI) have an increased risk for major malformations compared with spontaneously conceived pregnancies. Patients have to be counseled about these risks. The question is where these increased risks originate. At present, there are insufficient data available from pregnancies established following hormonal treatment or intrauterine insemination cycles. Therefore, the question is still open for debate, whether either in vitro culture or infertility per se or perhaps other components of the treatment cycle contribute to this risk. There is some evidence that at least the ICSI technique or the in vitro culture technique is not the only or most prominent factor. A long time to pregnancy with subsequent spontaneous pregnancy results in a similar risk profile as pregnancies following infertility treatment. This article discusses a possible pathogenetic model for these observations.

Female↗
PubMed2004

Polyalanine expansion in HOXA13: three new affected families and the molecular consequences in a mouse model.

Polyalanine expansions in two of three large imperfect trinucleotide repeats encoded by the first exon of HOXA13 have been reported in hand-foot-genital syndrome (HFGS). Here we report additional families with expansions in the third repeat of 11 and 12 alanine residues, the latter being the largest expansion reported. We also report a patient with a novel, de novo 8-alanine expansion in the first large repeat. Thus, expansions in all three large HOXA13 polyalanine repeats can cause HFGS. To determine the molecular basis for impaired HOXA13 function, we performed homologous recombination in ES cells in mice to expand the size of the third largest polyalanine tract by 10 residues (HOXA13(ALA28)). Mutant mice were indistinguishable from Hoxa13 null mice. Mutant limb buds had normal steady-state Hoxa13 RNA expression, normal mRNA splicing and reduced levels of steady-state protein. In vitro translation efficiency of the HOXA13(ALA28) protein was normal. Thus, loss of function is secondary to a reduction in the in vivo abundance of the expanded protein likely due to degradation.

Animals↗
PubMed2004

Pregnancy course and outcome after intracytoplasmic sperm injection: a controlled, prospective cohort study.

OBJECTIVE: To determine pregnancy course and major malformation rate after intracytoplasmic sperm injection (ICSI). DESIGN: Prospective, controlled, multicenter, nationwide German cohort study. SETTING: Tertiary infertility centers in Germany. PATIENT(S): Three thousand three hundred seventy-two children and fetuses and 8,016 children and fetuses after the 16th week of gestation in pregnancies after ICSI and natural conception, respectively. INTERVENTION(S): Standardized prospective follow-up. MAIN OUTCOME MEASURE(S): Major malformation rate. RESULT(S): The major malformation rate was 8.7% (295/3,372) for the ICSI cohort and 6.1% (488/8,016) for the population-based control cohort (relative risk, 1.44 [1.25-1.65]). After adjustment for risk factors, the risk declined (adjusted odds ratio, 1.24 [95% CI, 1.02-1.50]). Regarding singletons, there was a significant difference for birth weight and gestational age, with a higher number of preterm and low birth weight children in pregnancies achieved after ICSI. CONCLUSION(S): Children who are born after intracytoplasmic sperm injection have an increased risk of a major congenital malformation compared with those born after spontaneous conception. This risk is mainly due to paternal and maternal risk factors, which are more prevalent in couples who use ICSI for reproduction. An infertility-linked risk is highly probable for the observed findings. A technique-related risk, however, cannot be ruled out.

Birth Weight↗
PubMed2004

Development of children born after IVF and ICSI.

Follow-up studies of pregnancies as well as children born following assisted reproductive technologies are of utmost interest to provide a reliable basis for patient counselling. Especially in recent years, studies of high quality have been performed and published, showing some slight but significantly increased risk for pregnancy complications as well as major malformation rate following IVF and intracytoplasmic sperm injection (ICSI). The health status and subsequent development of children born seems to be comparable to those after spontaneous conception up to the age of 5 years. The study of Bonduelle and co-workers, published in this issue of Reproductive Biomedicine Online, contributes further to the follow-up information available for children born after ICSI. However, there are some limitations for all these follow-up studies, which have to be taken into account, when interpreting results. These are discussed in this commentary.

Case-Control Studies↗
PubMed2004

Steroid sulfatase (STS) expression in the human temporal lobe: enzyme activity, mRNA expression and immunohistochemistry study.

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are suggested to be important neurosteroids. We investigated steroid sulfatase (STS) in human temporal lobe biopsies in the context of possible cerebral DHEA(S) de novo biosynthesis. Formation of DHEA(S) in mature human brain tissue has not yet been studied. 17 alpha-Hydroxylase/C17-20-lyase and hydroxysteroid sulfotransferase catalyze the formation of DHEA from pregnenolone and the subsequent sulfoconjugation, respectively. Neither their mRNA nor activity were detected, indicating that DHEA(S) are not produced within the human temporal lobe. Conversely, strong activity and mRNA expression of DHEAS desulfating STS was found, twice as high in cerebral neocortex than in subcortical white matter. Cerebral STS resembled the characteristics of the known placental enzyme. Immunohistochemistry revealed STS in adult cortical neurons as well as in fetal and adult Cajal-Retzius cells. Organic anion transporting proteins OATP-A, -B, -D, and -E showed high mRNA expression levels with distinct patterns in cerebral neocortex and subcortical white matter. Although it is not clear whether they are expressed at the blood-brain barrier and facilitate an influx rather than an efflux, they might well be involved in the transport of steroid sulfates from the blood. Therefore, we hypothesize that DHEAS and/or other sulfated 3beta-hydroxysteroids might enter the human temporal lobe from the circulation where they would be readily converted via neuronal STS activity.

Adolescent↗
PubMed2004

Medical management of endometriosis: a systematic review.

Endometriosis is an important clinical problem in routine practice. Besides the problems of dysmenorrhea, dyspareunia and chronic abdominal pain, women with endometriosis are often infertile. We performed a systematic literature review on two issues: firstly, we clarified which medical treatment options have been investigated in prospective, randomized studies. Secondly, potential future treatments, still being preclinically investigated, were examined. A meta-analysis was not possible as the studies varied too much in their protocols and inclusion and exclusion criteria, as well as in the drugs and doses administered. Gonadotropin-releasing hormone (GnRH) agonists, progestins and oral contraceptives all appear to offer certain advantages for endometriosis patients. GnRH agonists appear to be the most effective but they are expensive and long-term treatment is not possible because of loss of bone mineral density. Estrogen add-back may offer some benefit for the clinical complaints of patients, but it may reduce the efficacy of GnRH agonists. Progestins have the best clinical profile and a good cost-effectiveness balance; however, most studies found that they were not as effective as GnRH agonists. Oral contraceptives are only effective during treatment and have a high relapse rate after therapy is completed. Future options may include the use of GnRH agonists, selective estrogen receptor modulators (SERMs) and anti-estrogens, as well as immunomodulators.

Danazol↗
PubMed2004

Pseudohypoaldosteronism type 1 and the genes encoding prostasin, alpha-spectrin, and Nedd4.

Pseudohypoaldosteronism type 1 (PHA1), a rare disorder of infancy, presents with potential life-threatening salt wasting and failure to thrive. Thus far, PHA1 has been attributed to mutations affecting the mineralocorticoid receptor or any of the three subunits assembling the amiloride-sensitive epithelial sodium channel (ENaC). However, a lot of patients with a phenotype resembling PHA1, show no defects in these proteins, making it likely that further genes are involved in the aetiology of this disease. Recent studies have elucidated additional participants (alpha-spectrin and members of the families of transmembrane serine proteases, ubiquitin-protein ligases, and serum- and glucocorticoid-regulated kinases, respectively) regulating and/or interacting in the complex pathway of sodium retention in the amiloride-sensitive distal nephron. This led us to investigate whether PHA1 can also be associated with mutations in some of these genes. Our data suggest that at least the prostasin gene might be excluded as a causative locus.

Endosomal Sorting Complexes Required for Transport↗
PubMed2003

Unilateral follicular aspiration and in-vitro maturation before contralateral oocyte retrieval: a method to prevent ovarian hyperstimulation syndrome.

BACKGROUND: Five women undergoing intracytoplasmatic sperm injection (ICSI) considered to be at high risk of developing an ovarian hyperstimulation syndrome (OHSS) from March to July 2002 underwent unilateral follicular aspiration. METHODS: When >/=15 follicles of 12-15 mm diameter in each ovary and a serum estrodial level >/=2500 pg/ml was present, follicular aspiration was performed unilaterally without hCG administration. Ovarian stimulation was continued for 1-3 days in four women before human chorionic gonadotrophin (hCG) was given. In one woman hCG injection was administered at the evening after unilateral follicular aspiration. The oocyte retrieval from the contralateral ovary was performed 36 h after hCG injection. By unilateral follicular aspiration two to six germinal vesicle (GV) oocytes could be retrieved. After in-vitro maturation of those oocytes ICSI was performed. RESULTS: In four women one to two oocytes were fertilized and cryopreserved. In one case only one triploid pronucleus (3PN) was observed. At the contralateral ovum-pick up after hCG injection a median of 10 could be retrieved. After transfer of a median of 3 embryos, no pregnancy was achieved. Four of five patients developed a severe OHSS and were hospitalized for a median of 3 days. CONCLUSION: Unilateral follicular aspiration and continuation of stimulation therefore can not be recommended for the prevention of OHSS.

Chorionic Gonadotropin↗
PubMed2003

Use of recombinant human chorionic gonadotropin in ovulation induction.

To review the use of hCG and to describe the clinical benefit of recombinant hCG (r-hCG) based on the published results of prospective, randomized studies. Review of published articles. Tertiary infertility care center.None.None. Oocyte number and quality, luteal phase progesterone, pregnancy and OHSS rate, and local tolerability. The published data consistently show that single doses of 250 microg r-hCG and 5,000 IU urinary (u)-hCG produce similar clinical outcomes when used in infertility treatment cycles for timed intercourse, IUI, and IVF in terms of the number of oocytes retrieved, number of mature oocytes harvested, and fertilization and pregnancy rates attained. Single doses of 10,000 IU u-hCG also gave results comparable to single doses of 250 microg r-hCG. P levels in the midluteal phase were significantly higher with the use of r-hCG compared with u-hCG, and local injection site adverse effects were significantly less frequent, demonstrating the higher purity of the recombinant product. A single 500-microg dose of r-hCG led to a higher rate of ovarian hyperstimulation syndrome compared with a 250-microg dose, with no significant improvement in pregnancy rates.A single dose of 250 microg r-hCG was at least as effective as single doses of 5,000 or 10,000 IU u-hCG but offered the advantages associated with use of a recombinant product: local injection site adverse effects were significantly less frequent with r-hCG than with u-hCG.

Chorionic Gonadotropin↗
PubMed2003

Allopregnanolone serum levels and expression of 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase isoforms in hippocampal and temporal cortex of patients with epilepsy.

In the human central nervous system, progesterone is rapidly metabolised to 5 alpha-dihydroprogesterone which subsequently is further reduced to allopregnanolone (AP). These conversions are catalysed by 5 alpha-reductase and 3 alpha-hydroxysteroid dehydrogenase (3 alpha-HSD). Although different isoforms of both enzymes have been identified in the brain, our knowledge of their expression in the human brain remains limited. The aim of the present study was to investigate the mRNA expression of 5 alpha-reductase 1 as well as 3 alpha-HSD 1, 2, 3 and 20 alpha-HSD in brain tissue from patients with pharmacoresistant temporal lobe epilepsy (TLE). Specimens were derived from either the hippocampus or the temporal lobe cortex and from the tumor-free approach corridor tissue of patients with brain tumors. Quantification of different mRNAs was achieved by real time PCR. In addition, we provide data on simultaneous evaluation of serum AP concentrations. We could demonstrate that 3 alpha-HSD 1 was not expressed in the hippocampus and temporal lobe of patients with TLE. In the hippocampus and temporal lobe, the expression levels of 3 alpha-HSD 2 were about 20% of that in liver tissue, those of 3 alpha-HSD 3 about 7% and those of 20 alpha-HSD about 2%, respectively. In patients with TLE, expression of 3 alpha-HSD 2 was significantly higher in the hippocampus than in temporal lobe cortex tissue (P<0.006). AP concentrations did not correlate significantly with the mRNA expression levels of 5 alpha-reductase 1, 3 alpha-HSD 2 and 3 and 20 alpha-HSD in any of the patient groups under investigation. In conclusion, the present study demonstrates mRNA expression of 5 alpha-reductase 1 and 3 alpha-HSD 2 and 3 and 20 alpha-HSD in the hippocampus and temporal lobe of epileptic patients. These findings provide further molecular biological evidence for the formation and metabolism of neuroactive steroids in the human brain.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2003

Characterisation of estrogenic 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity in the human brain.

Estrogens play a crucial role in multiple functions of the brain and the proper balance of inactive estrone and active estradiol-17beta might be very important for their cerebral effects. The interconversion of estrone and estradiol-17beta in target tissues is known to be catalysed by a number of human 17beta-hydroxysteroid dehydrogenase (17beta-HSD) isoforms. The present study shows that enzyme catalysed interconversion of estrone and estradiol-17beta occurs in the human temporal lobe. The oxidative cerebral pathway preferred estradiol-17beta to Delta(5)-androstenediol and testosterone, whereas the reductive pathway preferred dehydroepiandrosterone (DHEA) to Delta(4)-androstenedione and estrone. An allosteric Hill kinetic for NAD-dependent oxidation of estradiol-17beta was observed, whereas a typical Michaelis-Menten kinetic was shown for NADPH-dependent reduction of estrone. Investigations of the interconversion of estrogens in cerebral neocortex (CX) and subcortical white matter (SC) preparations of brain tissue from 12 women and 10 men revealed no sex-differences, but provide striking evidence for the presence of at least one oxidative membrane-associated 17beta-HSD and one cytosolic enzyme that catalyses both the reductive and the oxidative pathway. Membrane-associated oxidation of estradiol-17beta was shown to be significantly higher in CX than in SC (P<0.05), whereas the cytosolic enzyme activities were significantly higher in SC than in CX (P<0.0005). Finally, real-time RT-PCR analyses revealed that besides 17beta-HSD types 4 and 5 also the isozymes type 7, 8, 10 and 11 show substantial expression in the human temporal lobe. The characteristics of the isozymes lead us to the conclusion that cytosolic 17beta-HSD type 5 is the best candidate for the observed cytosolic enzyme activities, whereas the data gave no clear answer to the question, which enzyme is responsible for the membrane-associated oxidation of estradiol-17beta. In conclusion, the study strongly suggests that different cell types and different isozymes are involved in the cerebral interconversion of estrogens, which might play a pivotal role in maintaining the functions of the central nervous system.

17-Hydroxysteroid Dehydrogenases↗