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S Ziebe

Publications and source records attributed to S Ziebe.

27 records · Page 2Linked to original sources
PubMed1996

[Micro-insemination with intracytoplasmic sperm injection].

Intracytoplasmic sperm injection (ICSI) is now established in the treatment of infertility. Fertilization is achieved by microinjection of a single spermatozoon into the ooplasma. Oligoasthenoteratozoospermia is the main indication, but ICSI is also used in cases of failed fertilization after standard IVF, retrograde ejaculation and male immunological infertility. In obstructive azoospermia ICSI is performed after aspiration of epididymal or testicular spermatozoa. In some anejaculatoric men spermatozon can be obtained following penile vibration or electro-stimulation, but they often have poor motility and ICSI may be used for fertilization. ICSI may also be used after thawing of semen cryopreserved prior to treatment of a malignant disease. Since 1991 the ICSI technique has been improved, and today the pregnancy rates are at least as good as after standard IVF. So far, studies of the foetuses and children born after ICSI show that the number of malformations and abnormal karyotypes is within the range of the normal population.

Female↗
PubMed1995

Sperm morphology using strict criteria after Percoll density separation: influence on cleavage and pregnancy rates after in-vitro fertilization.

The main purpose of the study was to evaluate the use of sperm morphology assessment by strict criteria on the post-Percoll separated spermatozoa used for oocyte insemination in an in-vitro fertilization programme. This study included a consecutive unselected series of 213 oocyte aspirations in 159 women. In 177 aspirations the patient had tubal infertility and in 36 unexplained infertility. Data have been analysed from 197 aspirations where the semen sample used for insemination had a normal sperm concentration (> or = 20 x 10(6)/ml). A total of 1413 oocytes were aspirated, resulting in 863 oocytes which were fertilized and cleaved (cleavage rate 61%). In all, 492 pre-embryos were transferred in 193 cycles, resulting in a pregnancy rate of 42% per transfer. Sperm morphology evaluation using strict criteria showed that Percoll separation significantly increased the percentage of sperm cells with normal morphology from 7.7 to 11.3%. Sperm morphology analysis showed that Percoll separation decreased the number of sperm samples in the 'poor prognosis pattern' group from 31 to 13% and increased the number of sperm samples classified as 'normal' from 16 to 33%. After Percoll separation the poor prognosis pattern group had a cleavage rate of 46%, which was significantly lower than in the good prognosis pattern and the normal groups. However, the poor prognosis pattern group had a significantly higher pregnancy rate than the normal group (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Insulinomimetic effect on glucose transport by epidermal growth factor when combined with a major histocompatibility complex class I-derived peptide.

Peptides derived from the alpha 1-region of the murine H-2Dk molecule enhance glucose uptake in rat adipose cells above the maximum obtained with insulin stimulation alone (Stagsted, J., Reaven, G. M., Hansen, T., Goldstein, A., and Olsson, L. (1990) Cell 62, 297-307). We now describe that epidermal growth factor (EGF) in combination with the same peptides, Dk-(61-85) and Dk-(62-85), stimulates cellular glucose uptake 5-7 times over the basal level, i.e. to 30-50% of the maximal insulin effect. EGF alone increased glucose uptake by only approximately 50% above basal and the peptide alone by 100% above basal. Maximal effect of EGF and peptide was reached in 10-20 min with 30 microM peptide (EC50 10-15 microM) and 50 nM EGF (EC50 1-2 nM). The effect of EGF and peptide on glucose uptake was additive to that of insulin and peptide until the maximal level attained with insulin and peptide was reached. The combined effect of EGF plus peptide on glucose transport was associated with a recruitment of GLUT4 molecules to the plasma membrane. However, the phosphatidylinositol (PI) kinase which is activated by insulin was not activated by EGF plus peptide. Thus, the effect of EGF plus peptide on glucose uptake seems independent of the activity status of the insulin receptor. 125I-Labeled EGF bound specifically to rat adipose cells with an apparent affinity of approximately 2 nM and Bmax approximately 5 x 10(3). However, the major histocompatibility complex (MHC) peptides did not affect EGF-stimulated internalization of EGF receptor, in contrast to their effect on the insulin receptors. Transforming growth factor alpha had an effect similar to EGF on glucose uptake. Three other peptides derived from other parts of murine MHC class I had no effect on glucose uptake in combination with EGF. Thus, EGF in combination with certain MHC class I-derived peptides is insulinomimetic concerning glucose transport and this effect is independent of the insulin receptor activity.

3-O-Methylglucose↗
PubMed1993

Impact of gonadotrophin dose on pre-embryo recovery and development in superovulated mice.

A dose-response analysis was performed by stimulating mice with Humegon, which contains approximately equal amounts of follicle stimulating hormone (FSH) and luteinizing hormone (LH). The effect of increasing stimulation was assessed by monitoring the number and developmental stages of pre-embryos flushed from the tubes, and the developmental potency of these pre-embryos after culturing for 72 h. Increasing the stimulation doses resulted in an increased recovery of 2-cell pre-embryos. A maximal plateau of 40-50 2-cell pre-embryos was reached after stimulation with 15-30 IU FSH/LH. Higher stimulation doses up to 50 IU FSH/LH showed no further increase in pre-embryo recovery. Increased stimulation doses did not affect the number of 1-cell pre-embryos or the number of pre-embryos which developed further than the 2-cell stage. An average of 88 +/- 1.7% of the flushed pre-embryos were 2-cell pre-embryos. The fraction of flushed pre-embryos which developed into blastocysts after 72 h of culturing was constant at all stimulation doses, with an average of 81 +/- 1.9%. A maximal plateau of 35-40 blastocysts was reached after stimulating with 15-30 IU FSH/LH. The group of pre-embryos at less advanced developmental stages and the group of degenerated pre-embryos showed a small but dose dependent increase in number. In conclusion, we found that increasing doses of Humegon resulted in an increased recovery of pre-embryos capable of preimplantation development. This increased recovery occurred despite the high level of LH contained in this FSH/LH stimulation.

Animals↗
PubMed1992

Serum levels of free androstenedione, testosterone and oestradiol are lower in the follicular phase of conceptional than of non-conceptional cycles after ovarian stimulation with a gonadotrophin-releasing hormone agonist protocol.

Serum concentrations of total and free androstenedione, testosterone and oestradiol were followed during the follicular phase in women undergoing ovarian stimulation for treatment by in-vitro fertilization and embryo transfer (IVF-ET) and compared to those in natural unstimulated cycles. In addition, 10 conceptional and 18 non-conceptional cycles were compared in an attempt to understand the background for successful IVF cycles. The ultra-short gonadotrophin-releasing hormone agonist protocol was used for ovarian stimulation. Throughout the follicular phase, levels of total and free androstenedione and oestradiol were significantly lower in conceptional than in non-conceptional IVF cycles. In addition, levels of free testosterone during the follicular phase were significantly lower in women who conceived compared to non-conceptional IVF cycles, whereas levels of total testosterone were similar. Levels of both free and total androstenedione increased significantly from the second day of the menstrual cycle until oocyte retrieval in non-conceptional IVF cycles, whereas levels in conceptional IVF cycles and unstimulated cycles showed no increase. On the day of oocyte retrieval levels of free and total androstenedione were significantly higher in non-conceptional IVF cycles than in conceptional IVF cycles and unstimulated cycles, which were similar. This study suggests that appropriate levels of free biologically active androgens and oestradiol are important parameters for successful conception.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Changes induced in serum protein profiles by ovarian stimulation during in-vitro fertilization--embryo transfer treatment: a comparison between conception and non-conception cycles.

The profiles of plasma protein concentrations during the follicular phase in unstimulated women and in women undergoing ovarian stimulation for in-vitro fertilization--embryo transfer (IVF-ET) treatment are described. Plasma protein concentrations are correlated with those of total oestradiol (protein-bound and free) and total progesterone. In addition, 10 conception cycles and 18 non-conception cycles are compared in an attempt to identify predictors of successful treatment. Ovarian stimulation caused a significant increase in follicular phase in serum concentrations of sex hormone binding globulin (SHBG), cortisol binding protein (CBP) and insulin-like growth factor binding protein 1 (IGFBP1). In contrast no increase was observed in unstimulated cycles. Serum levels of endometrial protein PP14 decreased significantly during the follicular phase in both stimulated and unstimulated cycles. Levels of pregnancy zone protein (PZP) were more than doubled at the time of oocyte aspiration compared to the unstimulated cycles. Albumin concentrations were unchanged by the stimulation. Throughout the follicular phase, levels of SHBG were significantly higher, and total oestradiol significantly lower in women who became pregnant, than in those who did not. Therefore, a low concentration of free, biologically active oestradiol seemed to favour pregnancy, as the concentration of albumin is similar in the two groups. The endometrial protein PP14 was significantly lower during the follicular phase in conception than in non-conceptional cycles. On day 2 of the treatment cycle, the PP14 concentration showed a 75% correct prediction of conception and non-conception cycles. These results suggest that levels of PP14 may predict successful IVF cycles even before hormonal treatment is commenced.

Adult↗