Biomedical subjects

K Fiedler

Publications and source records attributed to K Fiedler.

At least 37 records · Page 2Linked to original sources

PubMed1998

[Intracytoplasmic injection of epididymal and testicular sperm after failed heterologous insemination].

We report on our experiences with intracytoplasmic injection (ICSI) of epididymal and testicular spermatozoa (MESA, TESE) from azoospermic men whose wives had previously failed to become pregnant after several cycles of artificial insemination by donor (AID); because we do not perform AID treatment in our clinic, all these treatments were carried out in other fertility centers as well as the female diagnostic of sterility. In 3 husbands we could not find any testicular spermatozoa or spermatids, leaving 15 women under treatment. Of these 15 women, 9 became pregnant. This accounts for a pregnancy rate per patient of 60%. We believe that functional defects of the oocytes and somatizing psychological problems concerning AID are predominantly responsible for these results and that both problems can be overcome by ICSI. Besides, these results demonstrate that ICSI/MESA and ICSI/TESE are effective approaches in the treatment of azoospermic men and that using cryopreserved spermatozoa is not disadvantageous in the outcome of ICSI.

Adult↗

PubMed1998

[Intracytoplasmic sperm injection (ICSI) after previous failure of heterologous insemination].

We report on our experiences with 25 married couples that approached us for intracytoplasmatic sperm injection (ICSI) after previous failure of artificial insemination by donor (AID). AID has been carried out in several specialized fertility centers. We traditionally refrain from donor semen procedures. All patients have undergone at least 4 treatment cycles of AID, the maximum was 20. With exception of one all patients have been inseminated after ovarian hyperstimulation according to different protocols (e.g. GnRH-A/FSH, hMG; CC/hMG). Prior to ICSI we have confirmed male subfertility being in all patients of severe grade. All patients have been proven to have ejaculated spermatozoa. We have performed 71 treatment cycles for ICSI so far, 19 patients have become pregnant, 3 have aborted. The pregnancy rate per cycle is 26%, per embryo transfer 30%, and per patient 76%. We think that these results are primarily caused by so far unknown defects in oocytes and their function during fertilization. Besides, we assume psychosomatic causes maybe involved.

Adult↗

PubMed1998

[Danger of infection from communion cups--an underestimated risk?].

The problem of a risk of infection from the common use of chalices has been discussed controversially in literature. Opinions were mainly based on laboratory experiments and theoretical considerations. The authors examined bacterial counts and species existing under normal conditions after communion. For this purpose, contact samples were taken from the inside and outside of chalices at the rim. Staphylococci and alpha-haemolytic streptococci were found on all chalices examined. On more than 80%, there were apathogenic micrococci, nonhaemolytic streptococci, apathogenic neisseria and apathogenic corynebacteria as well as lactobacilli and bacilli. Staphylococcus aureus was found on 26.4% of chalices. Although the risk of infection for healthy persons from a commonly used chalice can be rated as low, it should not be underestimated for persons with reduced resistance and immunocompetence, or with reduced defences as a result of therapeutic measures. From the hygienic point of view, the most favourable approaches to avoid infection would be the use of individual chalices for all participants in the communion or the immersion of wafers or bread in wine or in grape juice by the priest (intinction).

Bacteria↗

PubMed1998

[Intracytoplasmic injection (ICSI) of cryopreserved testicular spermatozoa (Cryo-TESE): a retrospective study of the first 250 treatment cycles].

It is reported on the results of 250 treatment cycles in which we carried out intracytoplasmic injections (ICSI) with frozen and thawed testicular spermatozoa (cryo-TESE). Up to July 1997 we treated 127 patients, 225 embryo transfers were performed (90%), and an average of 2.3 preimplantation embryos were transferred. This resulted in 53 clinical pregnancies, six patients aborted (11.3%). The pregnancy rate was 21.2% per treatment cycle, 23.5% per embryo transfer, and 41.7% per patient. This so called cumulative pregnancy rate is still about to rise, because 49 out of the 72 non-pregnant patients are still in our ICSI-program. Twenty-two children are born, 2 twins and 1 triplet. All children are healthy and without any major malformations. We conclude from these results that using cryopreserved testicular sperm for ICSI is an effective and successful approach for the treatment of severe testicular insufficiency. In comparison to the use of native testicular sperm with the necessity of repetitive testicular biopsies, cryopreservation is advantageous in many concerns (e.g. logistic, organisatoric and financial) and is therefore recommended for clinical routine.

Female↗

PubMed1998

[Housing and health].

Most of our lifetime we stay indoors. Both the home environment and housing behaviour may promote health complaints and disease. The term "sick building syndrome (SBS)" is used to describe a complex of unspecific symptoms attributed to staying in an indoor environment. In contrast, "building-related illness" (BRI) designates specific diseases attributed to special factors of indoor environment. A number of factors is known to influence health in the indoor environment, such as indoor emissions, ambient air, indoor climate (temperature, air flow, humidity) optical influences, water supply and sewage disposal, sound waves (noise, vibrations), non-ionising radiation, construction and characteristic design features of a home (e.g. floor area, functionality) and also psychological factors. Epidemiological studies have revealed that dark and noisy homes, rooms with insufficiently insulated external walls, single glazing, heating by gas heaters fitted to external walls and too low humidity of indoor air will increase morbidity. A checklist based on medical considerations is presented permitting assessment of the health relevance of important areas/factors of the home environment by means of a scoring system.

Health Status↗

PubMed1997

Sorting determinants in the transmembrane domain of p24 proteins.

Members of the p24 family of putative cargo receptors are proposed to contain retrograde and anterograde trafficking signals in their cytoplasmic domain to facilitate coat protein binding and cycling in the secretory pathway. We have analyzed the role of the transmembrane domain (TMD) of a p24 protein isolated from COPI-coated intra-Golgi transport vesicles. CD8-p24 chimeras were transiently expressed in COS7 cells and analyzed by immunofluorescence and pulse-chase experiments. The localization and transit of the wild-type chimera from the endoplasmic reticulum (ER) through the Golgi complex involved a glutamic acid residue and a conserved glutamine in the TMD. The TMD glutamic acid mediated the localization of the chimeras to the ER in the absence of the conserved glutamine. Efficient ER exit required the TMD glutamine and was further facilitated by a pair of phenylalanine residues in the cytoplasmic tail. TMD residues of p24 proteins may mediate the interaction with integral membrane proteins of the vesicle budding machinery to ensure p24 packaging into transport vesicles.

Amino Acid Sequence↗

PubMed1997

Mapping the protein composition of trans-Golgi network (TGN)-derived carrier vesicles from polarized MDCK cells.

In polarized MDCK cells, proteins and lipids are sorted in the trans-Golgi network /TGN) and packaged into different vesicular carriers that are delivered to the apical or basolateral cell surface. To gain insight into the sorting and trafficking machinery, we have previously isolated TGN-derived carrier vesicles from perforated MDCK cells. The composition of immuno-isolated apical and basolateral carriers was mapped by two-dimensional (2-D) gel electrophoresis. Here we describe the identification of several components of the vesicle fraction by using three different methods. 2-D gel comigration was performed with carrier vesicles isolated from metabolically labeled MDCK cells and human epidermal keratinocyte lysates. This allowed us to assign eleven known components by a comparison with the comprehensive keratinocyte 2-D gel database. These comprised two members of the 14-3-3 family of proteins that have been implicated in vesicular trafficking. Five proteins were purified from preparative 2-D gels and identified by peptide microsequencing, including the beta1 and beta2 subunit of trimeric G proteins and an annexin II variant. A member of the SNARE family of proteins was identified by immunoblotting. The combination of 2-D gel electrophoresis and 2-D gel databases allows the rapid assessment of the purity of subcellular fractions and to characterize components involved in vesicular transport.

Amino Acid Sequence↗

PubMed1997

Molecular genetic evidence for subtypes of oligoastrocytomas.

The histogenesis of oligoastrocytomas remains controversial, with some data arguing similarity of oligoastrocytomas to astrocytic tumors, and other data suggesting closer relationships with oligodendroglial neoplasms. Since the molecular genetic changes in astrocytomas differ from those of oligodendrogliomas, we characterized 120 astrocytic and oligodendroglial tumors, including 38 oligoastrocytomas, for genetic alterations that occur disproportionately between astrocytomas and oligodendrogliomas, i.e. TP53 gene mutations and allelic loss of chromosomes 1p, 17p and 19q. As previously reported, TP53 mutations were common in astrocytic gliomas, occurring in approximately half of WHO grade II and III astrocytomas, but in only 5% of WHO grades II and III oligodendrogliomas. Allelic losses of chromosomes 1p and 19q, however, were common in oligodendrogliomas (41% and 63%), but less frequent in astrocytomas (9% and 35%). Oligoastrocytomas showed TP53 mutations in 12/38 (32%) cases and allelic losses of chromosomes 1p and 19q in 52% and 70%, respectively. Most importantly, TP53 mutations and allelic losses on chromosomes 1p and 19q were inversely correlated in oligoastrocytomas (p < 0.011 and p < 0.019). These data suggest the existence of two genetic subsets of oligoastrocytomas, one genetically related to astrocytomas and the other genetically related to oligodendrogliomas. Histologically, those oligoastrocytomas with TP53 mutations were more often astrocytoma-predominant, while those with chromosome 19q loss were more often oligodendroglioma-predominant.

Adult↗

PubMed1997

Profiles of cognitive functioning in chronic spinal cord injury and the role of moderating variables.

A traumatic spinal cord injury (SCI) is accompanied by a documented moderate to severe head injury in significant numbers of SCI patients. In a previous study (Dowler et al., 1995), cognitive deficits were found in 41% of the SCI individuals who were studied with a chronic injury from a traumatic event. The present study investigated whether clinically useful subtypes of normal and impaired cognition could be identified in a chronic (M = 17 years postinjury) SCI sample using a cluster analysis of neuropsychological test performance. A battery of 16 neuropsychological tests was administered to 91 SCI patients and 75 control participants. Composite scores, reflecting performance in different cognitive domains, were derived from a factor analysis of the battery, and these scores were then used in the cluster analysis. A six-cluster solution generated the most distinct and clinically relevant SCI group profiles. Two of the cognitive profiles were characterized by normal functioning in all cognitive domains, but they were distinguished by differences in performance levels. The remaining four SCI groups (60% of the sample) showed clinically significant deficits in one or more cognitive domains, with different groups showing moderate attention and processing speed deficits, mild deficits in processing speed, executive processing difficulties, or moderate memory impairments. Though age and premorbid intellectual ability were strong predictors of the cognitive profiles of some SCI groups, when these factors were controlled, the findings suggested that the patterns of cognitive impairment were likely due to a potential concomitant head injury.

Adult↗

PubMed1997

[Moisture and mold on the inner walls of prefabricated building slabs--investigating a strange cause].

Reasons for indoor-moisture beyond the normal level can be caused by penetrating dampness, condensation-water, and apartment misuse. A fall in the air temperature below the dew point in connection with moulding inside buildings becomes evident mostly at places like badly insulated outer-walls or room-corners. In a number of houses built between 1980 and 1983 in the so called "Plattenbauweise" (prefabricated slabs), exclusively the inner-walls were covered in mould around cracks in the walls. Examinations showed connections between the apartment and the outer-corridor with a slight exchange of air through the cracks. Warm, wet air escaped from the apartment into the outer-corridor, and cold air entered the apartment from the outer-corridor. This temporary fall below the dewpoint caused by suitable variation of temperature probably resulted in the building materials and wallpapers becoming damp, as well as the growth of mould.

Air Microbiology↗

PubMed1997

[Johann Sigismund Elsholtz--the forgotten pioneer and German-speaking hygiene].

In 1682, the term "hygiene" appeared for the first time in the German language, in Johann Sigismund Elsholtz's Diaeteticon. In the author's meaning this term is used to describe the tenet of the maintenance of good health. In his book, Elsholtz who was physician at the court of Frederick William, the Great Elector of Brandenburg, makes suggestions for wholesome food and drinking. He demands the availability of clean water and of a good air and draws attention to the importance of personal hygiene. Thus, Elsholtz should be referred to as a German pioneer of hygiene whose recognition has been long overdue.

Germany↗

PubMed1996

Bimodal interaction of coatomer with the p24 family of putative cargo receptors.

Cytoplasmic domains of members of the p24 family of putative cargo receptors were shown to bind to coatomer, the coat protein of COPI-coated transport vesicles. Domains that contained dilysine endoplasmic reticulum retrieval signals bound the alpha-, beta'-, and epsilon-COP subunits of coatomer, whereas other p24 domains bound the beta-, gamma-, and zeta-COP subunits and required a phenylalanine-containing motif. Transit of a CD8-p24 chimera from the endoplasmic reticulum through the Golgi complex was slowed when the phenylalanine motif was mutated, suggesting that this motif may function as an anterograde transport signal. The either-or bimodal binding of coatomer to p24 tails suggests models for how coatomer can potentially package retrograde-directed and anterograde-directed cargo into distinct COPI-coated vesicles.

Amino Acid Sequence↗

PubMed1996

Constructive biases in social judgment: experiments on the self-verification of question contents.

Merely thinking about a proposition can increase its subjective truth, even when it is initially denied. Propositions may trigger inferences that depend not on evidence for truth but only on the semantic match with relevant knowledge. In a series of experiments, participants were presented with questions implying positive or negative judgments of discussants in a videotaped talk show. Subsequent ratings were biased toward the question contents, even when the judges themselves initially denied the questions. However, this constructive bias is subject to epistemic constraints. Judgments were biased only when knowledge about the target's role (active agent vs. passive recipient role) was matched by the semantic-linguistic implications of propositions (including action verbs vs. state verbs).

Adult↗

PubMed1996

[Pregnancy and delivery after in vitro fertilization (IVF) of human ova via intracytoplasmatic sperm injection (ICSI) of testicular sperm (TESE)].

This is a report on a pregnancy achieved by in-vitro fertilisation (IVF) with intracytoplasmatic sperm injection (ICSI) after testicular sperm extraction (TESE). Because of a bilateral absence of the ductus deferens, microsurgical epididymal sperm aspiration (MESA) was not possible. This anatomic situation was probably caused by a bilateral herniotom during childhood. The wife became pregnant in the first treatment cycle and meanwhile gave birth to a healthy boy. This case report demonstrates that the ICSI procedure is successful even with testicular spermia and extremely low sperm counts.

Adult↗

PubMed1996

A major transmembrane protein of Golgi-derived COPI-coated vesicles involved in coatomer binding.

Formation of non-clathrin-coated vesicles requires the recruitment of several cytosolic factors to the Golgi membrane. To identify membrane proteins involved in this budding process, a highly abundant type I transmembrane protein (p23) was isolated from mammalian Golgi-derived COPI-coated vesicles, and its cDNA was cloned and sequenced. It belongs to the p24 family of proteins involved in the budding of transport vesicles (Stamnes, M.A., M.W. Craighead, M.H. Hoe, N. Lampen, S. Geromanos, P. Tempst, and J.E. Rothman. 1995. Proc. Natl. Acad. Sci. USA. 92:8011-8015). p23 consists of a large NH2-terminal luminal domain and a short COOH-terminal cytoplasmic tail (-LRRFFKAKKLIE-CO2-) that shows similarity, but not identity, with the sequence motif-KKXX-CO2-, known as a signal for retrieval of escaped ER-resident membrane proteins (Jackson, M.R., T. Nilsson, and P.A. Peterson. 1990. EMBO (Eur. Mol. Biol. Organ.) J. 9:3153-3162; Nilsson, T., M. Jackson, and P.A. Peterson. 1989. Cell. 58:707-718). The cytoplasmic tail of p23 binds to coatomer with similar efficiency as known KKXX motifs. However, the p23 tail differs from the KKXX motif in having an additional motif needed for binding of coatomer. p23 is localized to Golgi cisternae and, during vesicle formation, it concentrates into COPI-coated buds and vesicles. Biochemical analysis revealed that p23 is enriched in vesicles by a factor of approximately 20, as compared with the donor Golgi fraction, and is present in amounts stoichiometric to the small GTP-binding protein ADP-ribosylation factor (ARF) and coatomer. From these data we conclude that p23 represents a Golgi-specific receptor for coatomer involved in the formation of COPI-coated vesicles.

Amino Acid Sequence↗

PubMed1996

[Triplet pregnancy after intracytoplasmatic sperm injection of cryopreserved testicular sperm].

For the first time we report on an intact and ongoing triplet pregnancy after intracytoplasmatic sperm injection of cryopreserved testicular sperm. Indication was azoospermia due to hypergonadotropic hypogonadism. The patient conceived in the third treatment cycle after 25 treatment cycles with donor sperm that had been carried out without success in two other treatment centers.

Adult↗

PubMed1996

Characterization of VIP36, an animal lectin homologous to leguminous lectins.

VIP36 was isolated from MDCK cells as a component of glycolipid-enriched detergent-insoluble complexes. The protein is localized to the Golgi apparatus and the cell surface, and belongs to a new family of legume lectin homologues in the animal secretory pathway that might be involved in the trafficking of glycoproteins, glycolipids or both. Here we show that VIP36 is N-glycosylated and expressed in organs abundant in epithelial cells as well as in non-epithelial organs. Our studies demonstrate that the recombinant exoplasmic/luminal domain of VIP36 binds Ca2+ and that the protein decorates internal membrane structures of MDCK cells in vitro that are distinct from the Golgi apparatus. This binding requires Ca2+ and can be specifically inhibited by N-acetyl-D-galactosamine. The recombinant protein was used for affinity chromatography. Glycopeptides obtained from [3H]galactose-labelled cells bind to VIP36 and can be eluted with N-acetyl-D-galactosamine. Our data imply that VIP36 functions as a lectin in post-Golgi trafficking.

3T3 Cells↗

PubMed1996

[Pregnancies after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) of testicular spermatozoa (TESE) from frozen semen].

This case report describes the possibility of establishing intact pregnancies by using cryopreserved testicular sperm for in-vitro-fertilization (IVF) with intracytoplasmatic sperm injection (ICSI). Because of a bilateral postinflammatory occlusion of the ductus deferens the patient underwent two cycles of IVF without ICSI by using epididymal sperm (MESA), however no fertilization occurred. In a third attempt with ICSI we used testicular sperm (TESE), because epididymal sperm was not detectable any longer. No pregnancy was established. In the forth treatment cycle again IVF/ICSI, now using cryopreserved and thawed testicular sperm. After embryotransfer (ET) of two preimplantation embryos into the uterine cavity, an intact singleton pregnancy was established. Meanwhile 15 further patients concept after IVF/ICSI using frozen and thawed testicular sperm. The German Embryo Protection Act (ESchG) prohibits the intentional fertilisation of more than three oocytes during one treatment cycle or the cryopreservation of human preimplantation embryos. Therefore it is mandatory to extract testicular sperm for every treatment cycle. Cryopreservation of testicular sperm is offering a legal possibility to avoid repeated testicular biopsies and has acceptable success rates for concerning couples.

Adult↗