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Biomedical subjects

K Sterzik

Publications and source records attributed to K Sterzik.

At least 73 records · Page 4Linked to original sources
PubMed1992

[Promoting pregnancy following partial zona dissection of the oocyte within the scope of in vitro fertilization].

Partial dissection of the zona pellucida (PZD) is one of several micromanipulatory methods for the treatment of male subfertility. PZD involves the mechanical introduction of a small hole in the zona pellucida of the oocyte prior to insemination. Thus, fusion with the oolemma and fertilization of the oocyte is facilitated for spermatozoa with impaired quality that otherwise would not be able to penetrate the zona. We have established this technique at our clinic and report on the first pregnancy achieved by PZD of the oocyte during our IVF programme.

Adult↗
PubMed1992

[Cytogenetics of unfertilized or uncleaved oocytes within the scope of in vitro fertilization. Relations to hormone content of follicular fluid].

Constituents of the follicular fluid (FF) have been suspected to influence fertilizability and cytogenetic constitution of human oocytes. Therefore, we analysed the FF concentrations of 17 beta-estradiol (E2), progesterone (P), testosterone (T), and prolactin (PRL) of 114 oocytes recovered for in vitro fertilisation (IVF). 46 of these oocytes were fertilised and transferred to the maternal uterus. Among the unfertilized gametes, 27 were not analysable. 30 were normal haploid, and 11 were classified as abnormal. There was no significant difference between fertilised and unfertilized oocytes for FF concentrations of E2, P, T, and PRL and for the E2/P ratios. Similarly, we detected no significant difference between normal and abnormal oocytes for these parameters.

Chromosome Aberrations↗
PubMed1992

[Ultrasound studies in pregnancy: technical principles and clinical safety].

Ultrasound examinations in pregnancy were carried out worldwide for over 30 years with no proof of adverse effects on either, mother or child. However, to evaluate the clinical significance of the numerous studies dealing with questions of safety of obstetrical sonography, a basic knowledge of its physical and technical aspects is needed. The present paper aims to convey these basics and should provide a review of the major publications concerned with the clinical safety of the method. Below clearly defined intensity levels, ultrasound scanning in pregnancy can still be considered unhazardous for both mother and child. However, it must be borne in mind, that the safety margin of Doppler flow measurements is lower for duplex compared with B-mode equipment. Therefore, for the present, duplex sonography should not be routinely applied in the first trimester of pregnancy.

Blood Flow Velocity↗
PubMed1992

[Early diastolic incisures in uteroplacental blood vessels. Experiences in patients with uneventful pregnancy and labor].

The frequency of diastolic notching in uteroplacental arteries was examined in a collective of 510 patients with uneventful pregnancies and deliveries. Notching appeared to be more frequent in the uterine than arcuate artery. It was seen to increase as pregnancy progressed and was markedly higher in the third compared with the second trimester. Uteroplacental notching occurred more frequently unilaterally and mainly affected contralateral sites of the placenta. Bilateral and retroplacental notching was the exception in normal pregnancies.

Blood Flow Velocity↗
PubMed1992

Reference values for resistance index and pulsatility index of uteroplacental Doppler flow velocity waveforms based on 612 uneventful pregnancies.

Using a 4-MHz continuous-wave Doppler device, standard rates were established for resistance index (RI) and pulsatility index (PI) of uterine and arcuate arteries of 612 patients with uneventful pregnancies and deliveries. From 18 to 41 weeks of gestation, neither RI nor PI of uterine or arcuate arteries proved to vary with gestational age, maternal heart rate, or maternal age. By contrast, a significant effect of placental location on the measurement results was found in both uterine and arcuate arteries. The differences between measurements on the placental or opposite site are more distinct in arcuate than in uterine arteries. Taking the 90th percentile as a localization gauge, cutoff levels of 0.52 (RI) and 0.98 (PI) were found in uterine arteries. In arcuate arteries, cutoff levels of 0.45 (RI) and 0.82 (PI) were found on the placental site or with a placenta without lateralization. On the nonplacental site of a lateralized placenta, the cutoff levels were 0.51 (RI) and 0.92 (PI).

Blood Flow Velocity↗
PubMed1992

Uteroplacental diastolic notching in 510 uneventful pregnancies.

In a collective of 510 patients with uneventful pregnancies and deliveries the rate of waveform notching in the uteroplacental flow velocity pattern was examined. Notching appeared to be significantly more frequent in the uterine than arcuate artery. It was unilateral and mainly affected placenta-contralateral sites. Bilateral notching or notching on placental site were the exception. In both flow patterns notching was seen to increase as pregnancy progressed and was slightly higher in the third compared to the second trimester.

Blood Flow Velocity↗
PubMed1992

Carbachol increases intracellular free calcium concentrations in human granulosa-lutein cells.

We investigated whether the stimulation of human granulosa-lutein cells with muscarinic and nicotinic receptor agonists can cause increases in intracellular free calcium (Ca2+), using Fura-2 microfluorimetry. The addition of carbachol (a non-selective muscarinic and nicotinic receptor agonist) to cultured human granulosa-lutein cells increased intracellular free Ca2+ levels. Concentrations as low as 10 nmol/l were effective. In contrast, nicotine did not evoke elevations of intracellular free Ca2+. Basal Ca2+ levels ranged around 70-140 nmol/l and maximal, carbachol-induced peaks reached 1.1 mumol/l. The carbachol-induced Ca2+ signal was abolished after preincubation of the cells with the muscarinic receptor antagonists quinuclidinyl benzilate or atropine, but it was not affected by removal of extracellular Ca2+. Further evidence for the involvement of intracellular Ca2+ stores is provided by experiments in the absence of extracellular Ca2+. While thapsigargin (a blocker of ATP-driven Ca2+ uptake by intracellular stores) and ionomycin (an ionophore by which Ca2+ is released from intracellular stores) evoked small Ca2+ transients, cells pretreated with these agents did not respond to carbachol any more. These data suggest the presence of a functional muscarinic receptor on human granulosa-lutein cells and imply the involvement of intracellular Ca2+ stores during the cellular response. These results also suggest the participation of the nervous system, acting through muscarinic receptors, in the control of the function of human granulosa-lutein cells.

Atropine↗
PubMed1992

[New perspectives of in vitro kallikrein treatment. II. Study of the hamster ovum penetration test in relation to the kallikrein-kinin system].

A significant enhancement of the fertilizing capacity of human spermatozoa by Kallikrein has recently been described in a former study. To assess the therapeutic possibilities it would be of great interest to know more about the biochemical effect of Kallikrein on the fertilizing capacity of human spermatozoa. This fact made the authors investigate 64 semen samples in which the binding score and the fertilizing capacity were determined after application of Kallikrein in a HOP-test (hamsterovum-penetration-test) and compared to the control. Furthermore these results were compared to the varying concentrations of the components of the Kallikrein-Kinin-system. An application of Kallikrein in the swim-up preparation resulted in a higher motility in patients with asthenozoospermia, whereas the patients belonging to the group of oligoasthenozoospermia showed a lower progressive motility compared to the control. The binding score (number of affixed spermatozoa) showed nearly the results in both preparations. On the other hand the fertilizing capacity in the Kallikrein preparation was significantly higher. A possible connection with the concentrations of the components of seminal plasma has not been found, yet, but regarding all results a direct enzymatic effect of Kallikrein on fertilizing potential can be assumed.

Animals↗
PubMed1992

[Obstetric cw-Doppler--results of a study of normal values. Effect of different variables on results].

Using a 4 MHz continuous wave Doppler device reference values for resistance index (RI) and pulsatility index (PI) of uterine and arcuate arteries as well as umbilical artery were established based on 510 patients with uneventful pregnancies and deliveries. Percentiles are more suitable localisation gauge than are standard deviations. Neither RI nor PI of maternal arteries proved to be dependent on gestational age in the observation period. If the heart rate are in physiological ranges no clinically relevant effect on the results were observed in either the maternal of the foetal copartment. By contrast umbilical artery shows a definite linear relation between the indices measured and gestational age. A significant effect of placental site on the measurement was found in both, uterine and arcurate arteries, but only the differences found in arcuates were of clinical value. An increase of diastolic notching was observed in both, uterine and arcuate arteries during pregnancy. Mostly only one vessel showed diastolic notching when observed in normal pregnancy. With a lateralized placenta the condition was more probable on the contralateral site.

Blood Flow Velocity↗
PubMed1992

[Type and incidence of cytogenetic abnormalities in unfertilized or uncleaved human oocytes within the scope of in vitro fertilization].

Human oocytes remaining unfertilized or uncleaved during in vitro fertilization (IVF) yield valuable information on the kind and frequency of numerical and structural chromosome aberrations after their fixation. This enables us to assess the maternal contribution to perturbations in the course of fertilization and early embryonic development. Therefore, 566 unfertilized or uncleaved oocytes from our IVF programme were processed for cytogenetic examination. 223 gametes were not analyzable. 260 oocytes were completely karyotyped and chromosome counts could be established for 83 cells. 243 eggs had the normal haploid chromosome complement whereas 100 cells (29.2%) were abnormal. In detail, we found the following aberrations: hypohaploidy = 10.2%, hyperhaploidy = 4.7%, diploidy = 9.0%, tetraploidy = 1.2%, structural anomalies = 2.6%, prematurely condensed sperm chromosomes = 3.2%. Six cells had to be considered in two of these categories. Our results and comparisons with other publications imply that the total rate of anomaies in human oocytes from stimulated cycles amounts to 20 to 30%. This high frequency might be one of the limiting factors for the success rate of IVF.

Adult↗
PubMed1992

[Ovarian stimulation with clomiphene is not a risk factor for extrauterine pregnancy].

In a retrospective cohort study of 252 patients with ectopic pregnancies the possible association between use of clomiphene citrate and the occurrence of an ectopic pregnancy was examined. Seventeen out of 252 patients had been treated with clomiphene. Epidemiologic data and animal experiments suggest, that there may be a role of clomiphene in the etiology of ectopic pregnancy. Marchbanks et al. [6] reported that patients who used clomiphene were found to have a relative risk of 10.0 for ectopic pregnancy. The analysis of our own data show an accumulation of classic risk factors as history of pelvic inflammatory disease or of microsurgery for treatment of tubal disease in the clomiphene group. The higher rate of ectopic pregnancies in patients who have been treated with clomiphene is more likely associated with the diagnosis of infertility than with the use of ovulatory-inducing agents. Clomiphene treatment is no independent risk factor in the etiology of ectopic pregnancy.

Clomiphene↗
PubMed1991

Sperm chromosomes and habitual abortion.

Genetic factors, especially numerical chromosome anomalies, play an important role in embryonic loss. Because somatic cell analysis cannot assess the risk of errors arising de novo during germ cell maturation, we investigated whether the male gametes from couples with habitual abortion carry a higher rate of anomalies than those from donors without reproductive dysfunction. Our results indicate that there is no significant difference between the two groups for the total rates of aneuploidy and structural anomalies. However, the levels of chromosome breaks and acentric fragments were significantly higher in the abortion group. The implications of this fact remain to be investigated.

Abortion, Habitual↗
PubMed1991

[Pregnancy after direct oocyte-sperm transfer (DOST)--a simple alternative to in vitro fertilization (IVF)].

We report on the first pregnancies achieved at our clinic following direct oocyte-sperm-transfer (DOST). Immediately after follicular aspiration, oocytes together with spermatozoa prepared by the swim-up-technique are transferred to the uterus in a manner similar to the embryo transfer following IVF. Our study population consists of 9 patients with bilateral tubal occlusion, accompanied by a male factor in three cases. Up to now, we have achieved four pregnancies, including one twin pregnancy, all occurring, when a male factor was absent. The method described appears promising in terms of efficiency, reduction in the costs and technical procedures during treatment of human infertility.

Embryo Transfer↗
PubMed1991

[Cytogenetic analysis of sperm chromosomes in couples with habitual abortion].

Genetic factors, especially numerical chromosome anomalies, play an important role in embryonic loss. Since somatic cell analysis cannot assess the risk of errors arising de novo during germ cell maturation, we investigated, whether the male gametes from couples with habitual abortion (group HA) carry a higher rate of anomalies, than those from donors without reproductive dysfunction (group K). Chromosomes were demonstrated after fusion of sperm with zona-free golden hamster ova. Our results indicate no significant difference between the two groups for the total rates of aneuploidy (HA: 3.6%, K: 2.0%) and structural anomalies (HA: 15.3%, K: 7.0%). However, the levels of chromosome breaks and acentric fragments were significantly higher in the abortion group (5.8% and 8.1%, respectively, vs. 2.4% each in group K). The implications of this fact remain to be investigated.

Abortion, Habitual↗
PubMed1991

[Receptivity of the endometrium: comparison of ultrasound and histologic findings after hormonal stimulation].

On the day of the scheduled embryo transfer, endometrial biopsies were taken from 53 patients of an IVF-programme. There was subsequent failure of fertilisation in all of these patients. The histologic pattern, compared with reflectivity and thickness of the endometrium was determined sonographically on the same day. All patients had been stimulated with hMG/hCG, and the ovaries and the endometrium had been monitored by transvaginal sonography. The reflectivity pattern was divided into grades (A to D according to Smith et al., 1984) and related to histological findings. The distribution of the grades was as follows: 16 patients (30%) grade A, 22 patients (42%) grade B, and 15 patients (28%) grade C. There was no case of grade D in our study. The results of histologic examination for grades A to C were not significantly different from each other. However, in only 37% of grade A, 63% of grade B and 66% of grade C, the endometrial response corresponded to the state of the cycle. Endometrial thickness for the receptive and non-receptive groups was not significantly different (8.8 +/- 0.29 mm vs. 9.13 +/- 0.4 mm). The results show no correlation between histologic findings and endometrial thickness or reflectivity. We therefore conclude, that sonographic determination of these parameters is not helpful in the evaluation of the degree of endometrial response.

Chorionic Gonadotropin↗
PubMed1991

[New perspectives of in vitro kallikrein treatment of human spermatozoa. I. Study of the hamster ovum penetration test in relation to different andrologic patient groups].

Whereas the enhancement of motility by Kallikrein is described several times, the effect on fertilizing capacity of human spermatozoa has not been investigated sufficiently yet. This fact induced the authors to start a further investigation on 64 patients by the means of zona-free hamster oocytes. The patients were differentiated by the parameters density and motility. The sample was divided up into two aliquots. Differing from the control the other aliquot was prepared with Kallikrein (5 KU/ml) before swim-up and preincubation for one hour at 22 degrees C. Comparing the results we found looking at the whole collective (n = 64) a significant enhancement of the fertilizing capacity. 34 of 64 patients showed an improvement, only 4 patients deteriorated. While the groups normo-, oligo-, and asthenozoospermia reached a higher fertilizing capacity under Kallikrein-treatment (probability of error 2.5%), a Kallikrein application in case of oligo-asthenozoospermia had no significant influence on fertilizing capacity. A view of the whole results leads to the assumption of a direct effect of Kallikrein and to the possibility of use for GIFT and IVF procedure.

Adult↗
PubMed1991

[The treatment of oligozoospermia with tamoxifen does not improve sperm quality].

As contradictory results have been obtained previously concerning the usefulness of tamoxifen in treatment of male infertility, we reevaluated its effects on 29 men presenting with idiopathic oligozoospermia. To determine whether a possible increase in sperm concentration might be correlated with an improvement of sperm quality, the hamster ovum penetration (HOP) test and the hypo-osmotic swelling (HOS) test were including as additional tests of sperm function. Patients were treated with tamoxifen (20mg/day) for 3 months. After already 4 weeks and continuing until the end of the study, tamoxifen had a significant effect (P less than 0.001) on blood levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), testosterone (T), and estradiol (E2). Prolactin (PRL) concentrations were not altered significantly (P greater than 0.05) after 3 months. There was no significant improvement (P greater than 0.05) of conventional semen parameters (volume, concentration, motility, morphology), and of HOP and HOS test results. Due to this lack of correlation between a rise in hormone levels and improvement of sperm quality, tamoxifen treatment of patients with idiopathic oligozoospermia is of questionable value.

Adult↗