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Biomedical subjects

G H Zeilmaker

Publications and source records attributed to G H Zeilmaker.

At least 19 recordsLinked to original sources
PubMed1995

Minimal monitoring of ovarian hyperstimulation: a useful simplification of the clinical phase of in vitro fertilization treatment.

OBJECTIVE: To investigate the feasibility of IVF treatment with minimal monitoring during ovarian hyperstimulation. DESIGN: Retrospective analysis and prospective study with real-time control group. SETTING: Transport IVF program with transport clinic and satellite clinics. PATIENTS: One hundred consecutive IVF cycles monitored at a transport clinic and 100 concurrent consecutive cycles monitored at satellite clinics, using the same stimulation-monitoring protocol and resulting in oocyte aspiration, are compared retrospectively for the number of ultrasound (US) measurements carried out during monitoring and for results of IVF treatment. No patient selection took place. After introduction of a minimal monitoring protocol at a transport clinic, a prospective study was started comparing 100 minimal monitoring cycles at a transport clinic with 100 concurrent conventional monitoring cycles at satellite clinics, all resulting in oocyte aspiration. Patients entered the retrospective or prospective study only once. In all cases the same laboratory facility was used. Monitoring of ovarian hyperstimulation was done with US measurements only. Cycles were canceled for impending ovarian hyperstimulation syndrome (OHSS) when > 35 follicles were seen to develop during hyperstimulation. RESULTS: Retrospective analysis shows no difference for the average number of US measurements at transport and satellite clinics (2.8 +/- 0.9 and 3.0 +/- 1.0; mean +/- SD). No differences were found in the number of ongoing pregnancies obtained in the two groups: 22 and 18, respectively. One case of severe OHSS occurred in the satellite clinic group. Introduction of minimal monitoring at the transport clinic gives a significant reduction of the average number of US measurements at the transport clinic compared with satellite clinics, where conventional monitoring continued to be used (1.5 +/- 0.8 versus 2.8 +/- 0.9). Ongoing pregnancies at transport and satellite clinics numbered 33 and 26, respectively. In both groups one patient developed severe OHSS. Sixty-two percent of cycles at the transport clinic were monitored with one US measurement only. No cancellations for impending OHSS occurred during the study period. CONCLUSION: A large group of patients need only one US measurement during monitoring of ovarian hyperstimulation. Minimal monitoring gives a useful further simplification of the clinical phase of IVF treatment, without adverse effects on treatment outcome and incidence of OHSS.

Ambulatory Care Facilities↗
PubMed1992

Comparison of results obtained with human serum and a protein solution as a supplement for in vitro fertilization culture medium.

A prospective controlled study was performed to compare the PRs obtained after use of a uniform IVF culture medium containing a pasteurized serum protein solution or patient serum. The ongoing PRs per ET in the serum and the protein solution group were 32% and 28%, respectively (not significant). Culture of supernumerary embryos showed blastocyst formation and even hatching with both supplements. The PR will not drop when this protein solution is used as a protein supplement in IVF culture medium instead of patient serum.

Blood↗
PubMed1992

Vaginal disinfection with povidon iodine and the outcome of in-vitro fertilization.

In a prospective randomized study, the influence was assessed of vaginal disinfection with a 1% solution of povidon iodine (Betadine), before performing a transvaginal ultrasound-guided oocyte retrieval, on fertilization, cleavage rate and pregnancy rate. The outcome of 334 oocyte retrievals was studied. In 160 cases, Betadine was used and in the remaining 174 cases, normal saline was used. No differences in the fertilization and cleavage rates were found (fertilization 45.5% versus 47.8%, cleavage 49.8% versus 52.1% in the Betadine and normal saline groups respectively). However the pregnancy rate was significantly higher in the normal saline group (17.2% versus 30.3% clinical pregnancies per embryo transfer). No increase in infection risk occurred in the saline group.

Disinfection↗
PubMed1992

Compensatory synaptic growth in the rod terminals as a sequel to partial photoreceptor cell loss in the retina of chimaeric mice.

In the retina of chimaeric mice of rd and wild-type genotypic combination, selective loss of rd/rd photoreceptor cells, after initial development, leads to a mosaic retina with variable amounts of normal photoreceptor cells present over the retinal surface. In some of the rod terminals of these retinas the synaptic complexes with the second order retinal neurons are seen to contain multiple synaptic ribbons and an increased number of profiles of the postsynaptic elements. These changes are observed only in the rod terminals and not in the cone pedicles. Computer aided three-dimensional reconstruction of the altered synapses shows that these changes result from an increase in the number of synaptic sites, characterized by multiplication of the synaptic ribbons and enlargement of the second order neuronal processes. A quantitative analysis of such synapses, based on serial electron micrographs, shows that these are most frequently located in the retinal regions of the chimaeric individuals that have suffered maximum photoreceptor cell loss. Thus synaptic growth appears to take place as a reaction to the reduction of afferent input to the postsynaptic components. These findings demonstrate persistent synaptic plasticity in the rod terminals of mammalian retina during the maturational phase of late postnatal development. Compensatory synaptic growth in the rod terminals, as recorded here, can have important implications for the maintenance of visual sensitivity in the diseased or ageing retina.

Animals↗
PubMed1991

The influence of contamination of culture medium with hepatitis B virus on the outcome of in vitro fertilization pregnancies.

Heat-inactivated human serum is added to the culture medium used for in vitro fertilization and other forms of assisted conception. Because one batch of pooled serum contained hepatitis B virus, an epidemic occurred among women participating in the treatment program. Seventy-nine women had serologic proof of hepatitis B infection. This incident gave the opportunity to study the effect of hepatitis B virus on pregnancy outcome and the newborn. The situation is unique because the preimplantation embryo was exposed to hepatitis B virus or the pregnancy was complicated by a (sub)clinical infection. Twenty-four women were or became pregnant while having an acute hepatitis B infection. Five pregnancies ended in abortion. The remaining 19 pregnancies ended in the birth of 24 children. No evidence for any harmful effect of exposure to hepatitis B virus in the embryonic or fetal period on the newborn could be found.

Adult↗
PubMed1990

Transcervical intrafallopian transfer of zygotes.

Reportedly, gamete intrafallopian transfer and zygote intrafallopian transfer are successful methods in assisted conception. This pilot study describes the experiences and results of a recently developed technique of vaginal transcervical intrafallopian transfer. In a group of 38 women with unexplained infertility, oocytes were retrieved. In 25 patients, pronucleate embryos were transferred to the fallopian tubes. A positive pregnancy test was reported in 8 cases. Considerations pertaining to this method and technical implications are discussed.

Adult↗
PubMed1990

Double fertilization in vitro and the origin of human chimerism.

A human embryo consisting of two cells, each containing two pronuclei, was found in the IVF laboratory. The most likely explanation for this phenomenon is a parthenogenetic activation of an oocyte leading to immediate cleavage and followed by double fertilization. Human chimerism may originate in this way.

Adult↗
PubMed1989

The influence of the interval between in vitro fertilization and embryo transfer and some other variables on treatment outcome.

This prospectively randomized study compares the outcome of 434 ETs 48 to 52 hours after insemination (day 2) and 324 ETs 72 to 76 hours after insemination (day 3). The influence of the interval between insemination and ET was assessed, as well as that of the number of embryos transferred, embryo quality, and the presence of supernumerary embryos. The mean number of embryos transferred after 2 and 3 days was equal (2.9 embryos/ET). The pregnancy rates per ET were not significantly different (21.9% versus 23.5%), but a higher percentage of viable pregnancies was observed after ET on day 3 (88.2% against 69.5% following ET on day 2). Treatment outcome was positively correlated with the number of embryos transferred and the presence of supernumerary embryos.

Abortion, Spontaneous↗
PubMed1988

Retinal damage by constant light in chimaeric mice: implications for the protective role of melanin.

Adult chimaeric mice, containing varying proportions of albino and pigmented cells in their ocular tissues, were exposed to constant light for 5 weeks and the distribution of the surviving rod perikarya in the retina and of the pigmented cells in various eye tissues were compared. In chimaeras which were mostly albino, the retinal lesion was similar to that in pure strain albino mice; in chimaeras with relatively more pigmented cells in their ocular tissues, the retina was unaffected as in fully pigmented mice. In chimaeras with amounts of pigmented cells in their ocular tissues varying between these two ends, lesions of intermediate degrees could be observed. Surviving rod cells in such chimaeric retinas were always found in regions adjoining the periphery. The location of the rod perikarya in such regions did not show an exact correlation with that of the overlying pigmented cells but regions of the outer nuclear layer with surviving rod perikarya were generally located in the half or quarter of the retina in which the overlying pigment epithelium also contained more pigmented cells than in the other regions. The proportions of the surviving photoreceptor cells varied between such chimaeras. The lesion appeared to be less extensive in individuals with more pigmented cells in the epithelium but no exact correlation was recorded. The findings suggest that while pigmentation in the iris reduces the amount of light reaching the retina, melanin in the pigment epithelium, in addition to preventing light reflection, may also play an antitoxic role, possibly as an antioxidative agent.

Albinism↗
PubMed1988

Ultrasonically guided percutaneous and transvaginal follicle aspiration; a comparative study.

In this study we compare the efficacy of ultrasonically guided percutaneous oocyte collection for in-vitro fertilization with ultrasonically guided transvaginal oocyte collection. Forty-seven patients were prospectively randomized into two groups. Twenty-four patients underwent percutaneous follicle aspiration and 23 patients underwent a transvaginal puncture. The number of aspirated oocytes per patient showed a statistically significant difference in the two groups: 2.5 for the percutaneous puncture versus 5.2 for the transvaginal procedure. The number of embryos per patient was 2.7 in the transvaginal puncture group versus 1.6 in the percutaneous puncture group. This difference was not statistically significant. The clinical pregnancy rate per patient was 12.5% with the percutaneous approach and 30.4% with the transvaginal technique. This difference was also not statistically significant. Since the transvaginal procedure also creates less discomfort to the patient and is less time-consuming it is concluded that this approach is preferable to the percutaneous puncture technique in obtaining oocytes for in-vitro fertilization.

Embryo Transfer↗
PubMed1988

The value and role of plasma 17 beta-oestradiol measurements during ovarian hyperstimulation for in-vitro fertilization.

Follicular aspiration was performed in 464 hyperstimulated IVF treatment cycles in patients with severe tubal damage as the sole cause of their infertility. In 413 cycles, one to four embryos could be replaced, resulting in 102 clinical pregnancies. In 458 treatment cycles, data on plasma E2 levels were available on days -3 and -2, in 322 cycles also on days -1 and 0, day 0 being the day of follicular puncture. Although the distribution of cycles leading to clinical pregnancy within the 5-95th centile for plasma E2 levels differed from that observed outside this range, these differences were of no statistical significance. These results indicate that IVF pregnancies occur in the presence of a wide range of E2 levels, during the 3-day period preceding follicular aspiration. The importance of plasma E2 measurements for treatment policy must, therefore, be reconsidered.

Clomiphene↗
PubMed1988

Factors influencing the outcome of successive IVF treatment cycles in attaining a follicular puncture.

An analysis has been made on data from 576 cycles in 300 patients regarding the chances of various superovulation protocols attaining a puncture in successive cycles. The cumulative proportion of patients with at least one successful stimulation increased from 77% at the first attempt, to 98% at the fifth attempt. Of the 576 stimulations, 440 (76%) resulted in a puncture. Age, the number of ovaries and the reaction to superovulation induction contribute to the outcome of a cycle, the chances being lowest for older individuals with one ovary and an inadequate reaction in the first treatment cycle. Changing the treatment protocol did not improve the outcome in subsequent gonadotrophin-induced cycles, even if combined with clomiphene citrate. Reasons for cancellation did not tend to recur, although the incidence of dominance and premature stimulation was significantly higher in patients aged greater than 35 years. Age-dependent chances of success were calculated.

Adult↗
PubMed1988

Development and degeneration of retina in rds mutant mice: analysis of interphotoreceptor matrix staining in chimaeric retina.

Chimaeric mice were produced by aggregating two morulae--one of homozygous rds mutant and another from a strain of mice with normal retina, which also differed in colour genes. The interphotoreceptor matrix in the retinal sections of these chimaeras was studied histochemically. In sections, stained with colloidal iron, regions with rds/rds photoreceptor layer, characteristically lacking the outer segments, showed more intense staining of the interphotoreceptor matrix, while regions with normal receptor outer segments showed less intense staining of the matrix. In sections, stained with toluidine blue, rds/rds regions showed more intense reaction along the pigment epithelial--photoreceptor interface and less intense reaction over the inner segments in comparison to the regions with normal photoreceptors. These differential staining reactions were independent of the overlying retinal pigment epithelial cell genotype and resembled the reaction patterns in the retina of pure strain controls of the same age. Small patches, showing rds/rds type staining were also observed within areas which appeared normal. We suggest that the altered properties of the interphotoreceptor matrix in the rds retina result from gene expression within the photoreceptor cells.

Animals↗
PubMed1987

Vitrification of mouse islets of Langerhans: comparison with a more conventional freezing method.

The possibility of cryopreservation of islets of Langerhans by vitrification using a mixture of cryoprotectants was investigated and the results were compared with a more conventional freezing method using Me2SO as cryoprotectant. Isolated mouse islets were divided into three groups: (1) control islets cultured for 6 days, (2) islets which were cryopreserved by vitrification after 2 days of culture, and (3) islets frozen in 1.5 M Me2SO after 2 days of culture. After warming, islets from groups 2 and 3 were cultured for 4 days. The thus treated islets were investigated with respect to insulin secretion in the presence of 2.5 or 25 mM glucose, survival during postwarming culture, morphology, and capability to reverse streptozotocin-induced diabetes. The insulin secretion in islets from all groups could be stimulated by a factor 5 or more by an increase in the concentration of glucose from 2.5 to 25 mM. The secretion of insulin in the presence of 2.5 mM glucose was similar in all groups of islets. The secretion of insulin in the presence of 25 mM glucose was slightly but not significantly lower in the cryopreserved islets than in the control noncryopreserved islets. The survival of islets during postwarming culture was comparable after cryopreservation with both methods, and islets from both groups could lower serum glucose in streptozotocin diabetic mice. We conclude that islets cryopreserved by the vitrification method are functional in vitro and in vivo. This method is quick, simple, and cheap because the use of complicated freezing equipment is avoided.

Animals↗