Publications by authors named "Tews G"

The PolariX TDS (Polarizable X-Band Transverse Deflection Structure) is an innovative TDS-design operating in the X-band frequency-range. The design gives full control of the streaking plane, which can be tuned in order to characterize the projections of the beam distribution onto arbitrary transverse axes. This novel feature opens up new opportunities for detailed characterization of the electron beam.

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Data regarding outcome and therapy of pregnancies in patients with homozygous antithrombin (AT) deficiency are very rare. We conducted a retrospective, descriptive investigation with emphasis on the obstetric history of eight women with homozygous AT deficiency heparin-binding site (HBS), who had at least one pregnancy. The aim of the study was to get a better insight into the outcome and identify suitable management procedures of pregnancy in this rare disease.

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Bemfola (follitropin alfa) (Finox AG, Switzerland), a new recombinant FSH, has a comparable pharmacological profile to that of Gonal-f (Merck Serono, Germany), the current standard for ovarian stimulation. A randomized, multi-centre, Phase 3 study in women undergoing IVF or intracytoplasmic sperm injection (n = 372) showed Bemfola yielding similar efficacy and safety profiles to Gonal-f. Women aged 20-38 years of age were randomized 2:1 to receive a single, daily, subcutaneous 150 IU dose of either Bemfola or Gonal-f.

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Since most current techniques analysing spermatozoa will inevitably exclude these gametes from further use, attempts have been made to enrich semen samples with physiological spermatozoa with good prognosis using special sperm-processing methods. A particular sperm-selection chamber, called the Zech-selector, was found to be effective in completely eliminating spermatozoa with DNA strand breaks. The aim of this study was to further analyse the subgroup of spermatozoa accumulated using the Zech-selector.

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Objective: To analyze whether a ready-to-use calcium ionophore improves outcomes, from fertilization to live birth, in patients with severe male factor infertility.

Design: Artificial oocyte activation offered to applicable patients over a 20-month period.

Setting: Specialized in vitro fertilization (IVF) centers in Austria and Germany.

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Normally, day-2 embryos show a crosswise arrangement of four cells with three blastomeres lying side by side. Cleavage anomalies include embryos that are characterized by a particular planar constellation of four blastomeres with presumed incomplete cleavage. Since little is known on the developmental fate of such conceptuses, within a 10-month period all consecutive patients were screened for day-2 planar embryos.

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Objective: To analyze whether the use of blastocyst intrafallopian transfer is a feasible option in a case of repeated difficult ET.

Design: Case report.

Setting: Public hospital.

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Intracytoplasmic sperm injection (ICSI) can be considered the most 'revolutionary' in vitro insemination technique because it has efficiently allowed the treatment of male factor infertility. Although ICSI has been successfully and safely applied worldwide for almost 20 years, currently, we have no real knowledge regarding the hypothetical long-term side effects on ICSI adults, given the increased likelihood of spermatozoa with defective nuclear content fertilising the oocytes. The aim of this review article is to investigate the most recent advances of performing ICSI in the safest possible manner, thus, minimising the theoretical hazards of this procedure.

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Objective: The increased use of assisted reproduction techniques has been accompanied by an increase in ectopic pregnancies with unusual location being associated with significant maternal morbidity and mortality. This article reports on seven cases of ectopic pregnancies with unusual location and an angular pregnancy. Diagnostic and therapeutic strategies are discussed and a brief review of literature is presented.

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a 25- year old woman with secondary infertility caused by a male factor was enrolled in our IVF/ICSI-ET program. Stimulation was performed in a long- protocol and ovarian stimulation, using rFSH follitropin beta, starting on the third day of the menstrual cycle. The rFSH dose per day was 900 IU-0 IU-0 IU-0 IU.

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Objective: To evaluate whether the use of theophylline improves sperm motility and treatment outcome in frozen-thawed testicular sperm extraction (TESE).

Design: Artificial sperm activation was offered to azoospermic patients between January and October 2010 in two different centers (identical lab conditions).

Setting: IVF units of public hospitals.

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Objective: This prospective study was set up in order to analyze whether additional treatment (cutting off supernumerous cumulus cells; adding hyaluronidase) of the cumulus-oocyte-complex (COC) would help to improve treatment outcome.

Material And Methods: COCs from 50 patients were prospectively subdivided into a control group A (no manipulation of COC) and two study groups. In group B, surplus cumulus cells were cut off using syringes, and in the second study group COCs were incubated with a 1:11 dilution of hyaluronidase (final concentration 7 IU/l).

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Sperm DNA fragmentation is increased in poor-quality semen samples and correlates with failed fertilization, impaired preimplantation development and reduced pregnancy outcome. Common sperm preparation techniques may reduce the percentage of strandbreak-positive spermatozoa, but, to date, there is no reliable approach to exclusively accumulate strandbreak-free spermatozoa. To analyse the efficiency of special sperm selection chambers (Zech-selectors made of glass or polyethylene) in terms of strandbreak reduction, 39 subfertile men were recruited and three probes (native, density gradient and Zech-selector) were used to check for strand breaks using the sperm chromatin dispersion test.

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This prospective study tested a new type of culture dish for the effects of individual culture and autotrophic factors. Within a 6-month period, 72 patients with nine or more fertilized eggs were enrolled in this prospective evaluation. Their 936 zygotes were split into three subgroups (individual culture, individual culture with contact to neighbours, group culture).

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In this study, day 1 to 4 serum anti-Müllerian hormone (AMH) level was analyzed in 2,741 patients attending our department for reproductive medicine or reproductive surgery, including a subgroup of 1,105 women who attended an assisted reproductive technology program because of a male factor as a presumably healthy subgroup. Day 1 to 4 serum AMH levels showed an age-dependent distribution and there is a wide range of AMH in each year of age analyzed, showing that even young women are at a risk of reduced ovarian reserve.

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After first successful attempts of IVF treatment medical action was for the better part faced with a legislative vacuum. It took more than ten years until appropriate legal provisions for treatment in reproductive medicine could be established in Austria, thus eliminating numerous legal uncertainties. Compared to other countries patients and physicians can be satisfied with both public support by social security legislation (IVF Support Fund Act, 2000) and the regulations of the Reproductive Medicine Act (FMedG, 1992).

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Objective: To compare the anti muellerian hormone (AMH) serum levels in women with and without endometriosis.

Design: A case-control study

Setting: Women's General Hospital, Linz, Austria.

Patient(s): Our study included a total of 909 patients undergoing in vitro fertilisation/intracytoplasmic sperm injection (IVF/ICSI) treatment or consulting our specific endometriosis unit.

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Although some post-thaw morphological predictors of pregnancy have been investigated in slow freezing of blastocysts, no such data have been published for vitrified and warmed blastocysts. Therefore, a prospective four-part score was applied to vitrified/warmed day-5 embryos to evaluate whether certain morphological parameters could serve as predictors of implantation, pregnancy and live birth. All morulae/blastocysts that were considered to be viable after warming were scored according to a previously unpublished grading system based on re-expansion, hatching (out of an artificial gap in the zona pellucida), extensive cytoplasmic granulation and presence of necrotic foci.

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The purpose of this case-control study was to compare implantation, pregnancy, and live birth rate of cryopreserved embryos with that of fresh embryos. A total of 1,488 assisted reproductive technology (ART) trials including 188 cryopreserved embryo replacement trials were reviewed. After proofing the exclusion criteria, 112 patients undergoing a cryopreserved embryo replacement (study group) were matched with 112 patients undergoing a fresh embryo transfer (control group).

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Objective: To analyze whether a change in three-dimensional structure of the zona pellucida could indicate suboptimal gamete quality.

Design: Prospective study.

Setting: Women's general hospital.

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Artificial reproductive techniques (ART) have become a routine and successful treatment of infertility. Twin pregnancies are more frequent after ART compared to spontaneous conception. Varying findings have been reported for the obstetric and perinatal outcome of ART twin pregnancies as compared to spontaneously conceived twin pregnancies.

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In terms of treatment outcome, little prognostic power is attributed to day-4 morphology. A day-4 score was applied to 56 patients separating non-compacting embryos from compacting (some areas of compaction) and fully compacted embryos. The latter were further subdivided according to the morphology of compaction.

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Objective: To analyze whether there is an increased perinatal risk for twin pregnancies after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI).

Study Design: The medical files of 216 twin pregnancies (group 1) conceived through IVF/ICSI and 377 spontaneously conceived twin pregnancies (group 2) were assessed retrospectively. Data on gestational age at delivery, mode of delivery, birth weight, neonatal intensive care unit admission, duration of hospitalization, perinatal mortality and malformations were recorded.

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