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Biomedical subjects

K Diedrich

Publications and source records attributed to K Diedrich.

At least 163 records · Page 9Linked to original sources
PubMed1999

A simple, inexpensive and effective artificial cycle with exogenous transdermal oestradiol and vaginal progesterone for the transfer of cryopreserved pronucleated human oocytes in women with normal cycles.

Supernumerary pronucleated stage oocytes (PN) are usually cryopreserved. PN are transferred in spontaneous, stimulated or artificial cycles. In this study, an artificial cycle with a transdermal therapeutic system was used for oestradiol release (Estraderm TTS 100) in combination with a targeted drug delivery system for vaginal progesterone release (Crinone 8%). Patients started transdermal 17beta-oestradiol treatment on cycle day 1. Only one clinical monitoring was necessary on day 14 for confirmation of satisfactory endometrial development and exclusion of ovulation by transvaginal ultrasound and endocrine determinations (oestradiol, progesterone and luteinizing hormone). Embryo transfer was performed on the third day of progesterone treatment (day 17). The first 25 cycles were recently completed in a prospective study; no cycles were cancelled due to ovulation or unsatisfactory endometrial development. In comparison with the previous protocol of embryo transfer in stimulated cycles in our clinic which required extensive ultrasound and endocrine monitoring, the pregnancy rate in these oestrogen- and progesterone-supplemented cycles was nearly twice as high (34.8%). Two pregnancies were even achieved with zygotes after micro-injection of frozen-thawed late spermatids extracted from testicular tissue (cryo-TESE). In these cycles, the Estraderm TTS 100/Crinone 8% protocol seems to be superior to stimulation protocols and even to other protocols reported so far for artificial cycles with exogenous oestradiol and progesterone treatment.

Administration, Cutaneous↗
PubMed1999

Genetics of male subfertility: consequences for the clinical work-up.

Major principles of genetic failures, chromosomal alterations and the most common syndromes associated with male subfertility should be taken into account before medical therapy and sophisticated techniques of assisted fertilization are applied to help a couple conceive. This review addresses the most common genetic reasons for male subfertility or infertility with special regard to the importance for the clinical work-up in daily routine and the potential risks for the conceptus.

Chromosome Aberrations↗
PubMed1999

Fertilization potential of spermatozoa with abnormal morphology.

One of the best discriminators for the fertilization potential of human spermatozoa is sperm morphology. The problem in the assessment of the sperm morphological characteristics is their pleiomorphism. Examination of spermatozoa with the light microscope can provide only limited information on their internal structure. More detailed examination of sperm structure using electron microscopy can reveal major, often unsuspected ultrastructural abnormalities. Results and cut-off values for sperm analysis depend on the criteria for normal morphology. World Health Organization recommendations provide a classification suitable for clinical practice. Clinically reliable cut-off limits for normal sperm morphology according to strict Tygerberg criteria were suggested to be 4% in in-vitro fertilization procedures. Patients with severe sperm head abnormalities have a lower chance of establishing successful pregnancies, even though fertilization may be achieved. The outcome of intracytoplasmic sperm injection is not related to any of the standard semen parameters or to sperm morphology. Sperm decondensation defects and DNA anomalies may be underlying factors for the unrecognized derangements of the fertilizing capacity of spermatozoa, regardless of sperm morphology. Centrosome dysfunction may also represent a class of sperm defects that cannot be overcome simply by the insertion of a spermatozoon into the ooplasm. In this article an overview on the composition and ultrastructure of spermatozoa is presented, while emphasizing sperm ultrastructural and sperm DNA anomalies and their effects on fertilization.

DNA↗
PubMed1999

Intracytoplasmic injection of round and elongated spermatids from azoospermic patients: results and review.

Microinjection is established as the method of choice in the treatment of severe male factor infertility as well as in azoospermic patients. Recent studies have shown that fertilization and cleavage can be achieved by injection of ejaculated as well as testicular elongated spermatids into oocytes. Here we report on the two first pregnancies worldwide resulting from elongated spermatid injection from frozen-thawed testicular tissue. Four patients with complete Sertoli cell-only syndrome (SCOS) and two with spermatogenetic maturation arrest were included in our microinjection programme. Tissues from open testicular biopsies were cryopreserved until the time of follicle puncture. A total of 67 oocytes were harvested. In the two patients with maturation arrest, cryopreserved elongated spermatids were successfully injected, while in two of the other four SCOS patients only cryopreserved round spermatids were available to be injected into the oocytes. Out of 18 injected oocytes, 10 were fertilized in the first group, while nine out of 49 injected oocytes showed fertilization and cleavage in the second group. Two clinical pregnancies were achieved with elongated spermatids from frozen-thawed testicular tissue, while no pregnancy was established in the case of round spermatids. This study confirms that fertilization, cleavage and pregnancy can be successfully achieved in cases with spermatogenetic maturation arrest by injecting cryopreserved elongated spermatids into oocytes. The literature on pregnancies following spermatid injection, as well as the problems using this technique and possible risks, are discussed.

Adult↗
PubMed1999

Interactions of ovarian steroids with pituitary adenylate cyclase-activating polypeptide and GnRH in anterior pituitary cells.

Pituitary adenylate cyclase-activating polypeptide (PACAP) releases LH and FSH from anterior pituitary cells. Although this effect is relatively weak, it has a strong sensitizing action on GnRH-induced gonadotropin secretion. Here we investigated the possibility that ovarian steroids, which are well-known modulators of LH secretion, interact with PACAP and GnRH in pituitary gonadotrophs. Rat pituitary cells were treated for 48 h with vehicle, 1 nmol/l estradiol, 1 nmol/l estradiol + 100 nmol/l progesterone or 48 h with 1 nmol/l estradiol and 4 h with 100 nmol/l progesterone. The cells were stimulated for 3 h with 1 nmol/l GnRH or 100 nmol/l PACAP. Estradiol treatment alone enhanced basal as well as GnRH- or PACAP-stimulated LH secretion. LH release was facilitated by additional short-term progesterone treatment. Long-term treatment with estradiol and progesterone led to reduced LH responses to GnRH and PACAP. Neither treatment paradigms affected cAMP production. However, estradiol treatment led to enhanced cAMP accumulation in quiescent or GnRH-stimulated cells. PACAP-induced increases of cAMP production were inhibited by estradiol treatment. After 7-h preincubation with 10 nmol/l PACAP, cells responded with enhanced LH secretion to GnRH stimulation. When steroid pretreatment was performed the responsiveness of gonadotrophs to low concentrations of GnRH was still increased. In contrast, at high concentrations of GnRH the sensitizing action of PACAP on agonist-induced LH secretion was lost in steroid-treated cells. There were no significant differences between the steroid treatment paradigms. It is concluded that estradiol but not progesterone acts as a modulator of adenylyl cyclase in gonadotrophs. The stimulatory effect of estradiol is thought to be involved in its sensitizing action on agonist-induced LH secretion. The inhibitory effect of estradiol on PACAP-stimulated adenylyl cyclase activities seems to be responsible for the loss of its action to sensitize LH secretory responses to GnRH.

Adenylyl Cyclases↗
PubMed1999

[Medical treatment of uterine fibroids with the LHRH antagonist: Cetrorelix].

A depot preparation of the LHRH-antagonist Cetrorelix was used for the preoperative treatment of 20 premenopausal women with symptomatic uterine fibroids to undergo surgery. In an open, prospective and randomised study, 60 mg of this depot preparation were administered i.m. at the second day of cycle. Patients were randomised for a second dosage of 60 mg or 30 mg to be injected on day 21 or day 28 of treatment according to the degree of estradiols' suppression (< 50 pg/mL). The operation was carried out after six or eight weeks of treatment according to the timing of second dosages administration. Weekly transvaginal sonography as well as MRI before and after Cetrorelix treatment were performed for fibroids volume assessment; 16 patients showed satisfactory suppression of gonadotrophins and sexual steroids. No flare up effect was to be observed. In this group of patients the maximum reduction in fibroids size was of 33.5% at the end of treatment. After 14 days of treatment the reduction was of 31.3%. Within the group of good responders (reduction of fibroids size > 20%) the volume of the biggest fibroid after 14 days of treatment was of 56.7% of the initial assessment. Although MRI showed minor mean shrinkage rates of only 25.4% of the initial volume, these differences in comparison to transvaginal sonography were not statistically significant. The avoidance of any flare up phenomenon by the LHRH-antagonist may explain this fast reduction in size. The basic advantages of this treatment modality are the reduction of treatment time with a fast restoration of the ovarian function. The rate of poor responders may be reduced by improving the galenic preparation.

Adult↗
PubMed1999

[Possibilities and limits of assisted reproduction].

The term assisted reproductive technologies (ART) describes all treatment procedures which include more than the natural intercourse to conceive. The most invasive procedure is intracytoplasmic sperm injection (ICSI), which was introduced in 1993. By ICSI the successful treatment of couples with severe male factor infertility, even in cases of azoospermia, became possible. In cases where only immature forms of spermatogenesis are present in the testicular tissue, pregnancies could also be achieved. The limiting factor with greatest influence on the success rate of ART procedures is the female's age. In this context the treatment of postmenopausal women by oocyte donation, as well as ooplasma donation to overcome the negative influence of the female's age on oocyte quality are extreme examples of ethically questionable ART procedures. Until now several 100,000 children worldwide have been born subsequent to ART and especially in vitro fertilisation. No increase in the malformation rate neither after IVF nor after IVF/ICSI have been reported so far. However, because of the lack of prospective controlled studies using standardised evaluation procedures and having enough statistical power to prove the security of ICSI for the newborn children, the German statutory health insurance bodies have ceased to pay ICSI costs as of July 1999. The data on the success of ICSI, the known data on the newborn and developing children and the decisions of the medical services of the German statutory health insurance bodies are presented in discussed in this paper.

Female↗
PubMed1998

Dual action of androgen on calcium signaling and luteinizing hormone secretion in pituitary gonadotrophs.

An increase in serum androgen levels associated with a suppression of cyclic gonadotropin secretion is frequently observed in females with impaired ovarian function. Here, we addressed the hypotheses that androgens (testosterone and dihydrotestosterone) alter gonadotropin secretion by modulating agonist-induced Ca2+ signaling and/or Ca(2+)-controlled exocytosis. In mixed populations of pituitary cells from female rats, addition of testosterone reduced basal and agonist (GnRH)-induced gonadotropin secretion in a concentration- and time-dependent manner. The suppressive actions of this androgen on gonadotropin secretion were observed over the full GnRH concentration range. Reduction in agonist-induced gonadotropin secretion was also observed after addition of dihydrotestosterone, indicating that the inhibitory action of testosterone is not mediated by its conversion to estradiol. Both the extracellular Ca(2+)-independent spike phase and extracellular Ca(2+)-dependent sustained phase of GnRH-induced gonadotropin secretions were affected by testosterone. In part, the inhibitory action of testosterone was mediated by attenuation of GnRH-induced InsP3 production and InsP3-dependent Ca2+ mobilization. In addition, testosterone exhibited a Ca(2+)-independent action on gonadotropin secretion, as documented by attenuation of high potassium-induced secretion without an affect on depolarization-induced Ca2+ signals. These results suggest that androgen inhibition of gonadotropin secretion occurs at two distinct steps in the secretory pathway, one prior to and one after elevation in cytosolic Ca2+ concentration.

Androgens↗
PubMed1998

Serum concentration of vascular endothelial growth factor cannot predict the course of severe ovarian hyperstimulation syndrome.

Vascular endothelial growth factor (VEGF) is stated to be a possible promoter of the development and the severity of ovarian hyperstimulation syndrome (OHSS). The secretion of VEGF in granulosa cells seems to be human chorionic gonadotrophin (HCG) dependent. In this prospective study, the data of 10 patients suffering from severe OHSS with ascites and pleural effusions (haematocrit, fluid balance, serum HCG, serum oestradiol) were analysed. The serum VEGF concentration declined during the period of clinical improvement but provided no additional diagnostic information for the further course of OHSS. VEGF was neither an early marker of improvement, nor of worsening of the clinical picture of the OHSS. Serum oestradiol concentrations and serum VEGF concentrations showed a statistical correlation (r = 0.33, P < 0.001). There was no correlation between haematocrit and VEGF, nor between serum HCG and VEGF. To conclude, although VEGF may be involved in the pathogenesis of OHSS, it is not an important clinical marker for the course of an OHSS.

Ascites↗
PubMed1998

The effect of multiple cryopreservation procedures and blastomere biopsy on the in-vitro development of mouse embryos.

Preimplantation genetic diagnosis is currently used in clinical practice. In experienced hands the biopsy procedure alone does not affect the further in-vitro and in-vivo developmental potential of animal and human embryos. No data exist on the combination of cryopreservation of embryos at the pronuclear and/or 8-cell stage and/or biopsy at the 8-cell stage. Pronuclear stages of mouse F1 hybrids (C57Bl/jxCBA) were harvested and divided into several experimental groups. The developmental rates of zygotes, which were neither biopsied nor cryopreserved were used as data control. Others were only cryopreserved at the pronuclear stage (C-PN), or at the cleavage stage (C-CS), or both. Each of these groups was also combined with or without a biopsy. Only the hatched blastocyst rate (HBR), but not the 'simple' blastocyst rate, showed significant differences between groups. Neither C-PN (HBR = 60.42%), nor C-CS (63.16%), nor a combination of both (59.46%) had an impact on the hatched blastocyst rate when compared with that of the control group (67.46%). The biopsy procedure (55.93%) also proved not to be harmful for the embryos. The embryos, which were C-PN and C-CS, and subsequently biopsied, showed a significantly lower hatched blastocyst rate (39.62%) than that of the control, C-PN, C-CS, and C-PN/C-CS groups (P < 0.05). The combination of C-PN and cleavage-stage biopsy also lead to a lower hatched blastocyst rate (42.22%), compared with that of the control group (P < 0.05). It was concluded that couples must be advised that an effect on embryos which have undergone a combined cryopreservation and micromanipulation procedure cannot be ruled out. However, cryopreservation at the pronuclear or at the 8-cell stage alone, or in combination with a biopsy procedure, does not influence the further development of the embryo.

Animals↗
PubMed1998

Treatment of uterine fibroids with a slow-release formulation of the gonadotrophin releasing hormone antagonist Cetrorelix.

A depot preparation of the third-generation gonadotrophin-releasing hormone (GnRH) antagonist Cetrorelix (SB-75) was used for preoperative treatment in twenty premenopausal patients with symptomatic uterine fibroids who were to undergo surgery. In a prospective, open, randomized setting 60 mg of Cetrorelix pamoate salt was administered i.m. on cycle day 2. Patients were randomized for a second dose of 30 or 60 mg of Cetrorelix depot, which was administered according to the degree of oestradiol suppression (<50 pg/ml) on treatment day 21 or 28. Surgery was done after 6 or 8 weeks of treatment, depending on second dosage administration. Weekly transvaginal sonography (TVS) and magnetic resonance imaging (MRI) before and after treatment was performed, for fibroid volume assessment. Sixteen patients showed satisfactory suppression of gonadotrophins and sex steroid secretion, avoiding any initial flare-up effect. In these patients a mean shrinkage rate of largest fibroid volume of 33.5% at the end of treatment could be observed according to TVS, while the mean shrinkage rate obtained after 14 days of treatment was 31.3%. In good responders (shrinkage >20%) largest fibroid volume at day 14 was approximately 56.7% of basic assessment. Although MRI showed minor mean shrinkage rates of only 25.4% of the initial volume, these differences in comparison to TVS assessment were not statistically significant. The avoidance of any initial flare-up in gonadotrophin secretion may explain this extremely fast reduction in fibroid size. The advantages of GnRH antagonist treatment in this indication consist in the short treatment time with a fast restoration of the ovarian function. The rate of poor responders may be reduced by using an improved slow release preparation.

Adult↗
PubMed1998

Ovarian hyperstimulation syndrome (OHSS) in a spontaneous pregnancy with fetal and placental triploidy: information about the general pathophysiology of OHSS.

An ovarian hyperstimulation syndrome (OHSS) in spontaneous pregnancies is a very rare event. Hence, clinicians might make wrong decisions, such as laparotomy, because of suspicion of an ovarian carcinoma, or severe complications such as renal insufficiency may develop because the diagnosis and treatment of OHSS are delayed. Here we report a case of a woman in the 15th week of gestation, presenting with a partial hydatidiform mole and a triploidy of fetus and placenta, with an ongoing and severe OHSS even after legal induced abortion. A low vascular endothelium growth factor (VEGF) concentration (50 ng/ml) was measured when human chorionic gonadotrophin (HCG) exceeded 1000 IU/l and was followed by VEGF concentrations >900 ng/ml, when the OHSS developed. The literature on spontaneous pregnancies associated with OHSS is reviewed, and possible reasons for the clinical course presented in this study and the reviewed reports are discussed. The findings in this case contribute to our theory that VEGF is a causative factor of OHSS, but has no impact on the course of this disease.

Abortion, Induced↗
PubMed1998

Principles of mammalian fertilization.

The principles of mammalian fertilization are defined in relation to studies of the intracytoplasmic injection of spermatozoa into human oocytes (ICSI). Sections are included on the production of mature oocytes and mature spermatozoa, sperm-oocyte interaction, and formation of the pronucleate oocyte. Current concepts in gametogenesis are discussed, including spermiogenesis, oogenesis, the biology and penetration of the zona pellucida including capacitation and the acrosome reaction, gamete fusion, the block to polyspermy and growth of the pronucleus. A concluding section relates the normal events of fertilization to those occurring after ICSI and discusses various types of anomalies found in the oocyte after ICSI.

Animals↗
PubMed1998

Ultrastructure of gametes and intracytoplasmic sperm injection: the significance of sperm morphology.

The aim of this study was to determine characteristic malformations of sperm ultrastructure in patients with severe subfertility undergoing intracytoplasmic sperm injection (ICSI). Although light microscopy (LM) can reveal major abnormalities of the three parts of the spermatozoon (head, mid-piece and flagellum), the various cell organelles of the spermatozoon and their fine structure remain unevaluated by LM. Insight into the submicroscopic organization of the spermatozoon and its complex organellar system may contribute to a better understanding of the preconditions for success or failure of fertilization. An in-depth evaluation of semen quality by transmission electron microscopy (TEM) can improve the diagnosis of male subfertility and can give substantial information about the fertilizing competence of spermatozoa. Thus, in this study 56 ejaculated sperm samples from patients with severe male subfertility or previous failed attempts at in-vitro fertilization were assessed by LM and TEM prior to ICSI to evaluate the most important sperm defects causing extreme subfertility. LM analysis was performed according to World Health Organization criteria. It could be confirmed that severe head defects are mostly involved in long-term infertility and fertilizing failure in classical IVF treatments. The most frequent head defects are disorders of the nuclear membranes and the acrosomal cap and disorganization of the chromatin structure. These defects of sperm fine structure seem to be associated with dysfunctional sperm-oocyte recognition, binding and fusion with the oolemma. Chromatin alterations and signs of decondensation or karyolysis are frequently associated with a deterioration of the nuclear membranes and may be due to impaired spermiogenesis. However, our results and the success of ICSI proved that severe sperm defects have no predictive value and do not impair the fertilization process, and also that the maturity of spermatozoa does not play an important role. Fine structure analysis revealed the pleiomorphology and heterogeneity of human spermatozoa.

Female↗
PubMed1998

New approaches to ovarian stimulation.

Suppression of endogenous hormone production by gonadotrophin-releasing hormone (GnRH) agonists followed by controlled ovarian hyperstimulation (COH) with human gonadotrophins, especially the so-called 'long protocol' has developed from second-line into first-line therapy. Due to this attitude premature luteinization can be safely avoided, enhancing therapeutic efficacy. Recombinant preparations of human follicle stimulating hormone (FSH) have been proven to be effective within COH according to the long protocol. The high purity of these compounds may have clinical advantages. GnRH antagonists could be successfully introduced in COH protocols. Also, daily injections in the midcycle phase according to the 'Lübeck protocol', as single or only dual administrations around day 9 seem to abolish any premature LH rises. Due to their different pharmacological mode of action, based on a classic competitive receptor blockage GnRH antagonists avoid any flare-up period and allow ovarian stimulation to start within the spontaneous cycle. Pregnancy rates are comparable to those after long protocol stimulation. Combination of softer stimulation regimes like clomiphene citrate and low dose HMG with midcycle administration of GnRH antagonists may be the way to a cheap, safe and efficient ovarian stimulation. It seems to be high time for modest forms of ovarian stimulation, lowering burden and risk for our patients.

Female↗