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Biomedical subjects

M Dorsch

Publications and source records attributed to M Dorsch.

At least 19 recordsLinked to original sources
PubMed2006

[Minimally invasive approach to implantation of a hip endoprosthesis].

Early experiences with the two-incision approach at the hip joint are reported. We started in July 2002 and until now 272 procedures have been performed. Blood loss (292 ml) and the need for rehabilitation are reduced, the patients will achieve a Harris Hip Score of more than 90 points within 6 or 8 weeks. Complications related to the approach primarily include irritation of the lateral femoral cutaneous nerve. During the learning curve when the initial shaft model was used, shaft fractures or fissures occurred in 4% of the cases. This complication was no longer observed with the ML Taper shaft model now employed (n=102). The development and establishment of minimally invasive approaches constitute a valuable and seminal option for implantation of hip endoprostheses. In the medium term, the time spent in rehabilitation could conceivably be reduced. Conventional approaches still represent the gold standard.

Adult↗
PubMed2005

Trauma and grief 2-7 years after termination of pregnancy because of fetal anomalies--a pilot study.

The aim of the study was to obtain information on the long-term posttraumatic stress response and grief several years after termination of pregnancy due to fetal malformation. We investigated 83 women who had undergone termination of pregnancy between 1995 and 1999 and compared them with 60 women 14 days after termination of pregnancy and 65 women after the spontaneous delivery of a full-term healthy child. Women 2-7 years after termination of pregnancy were expected to show a significantly lower degree of traumatic experience and grief than women 14 days after termination of pregnancy. Contrary to the hypothesis, however, the results showed no significant intergroup differences with respect to the degree of traumatic experience. With the exception of one subscale (fear of loss), this also applied to the grief reported by the women. However, both groups differed significantly in their posttraumatic stress response from women who had given spontaneous birth to a full-term healthy child. The results indicate that termination of pregnancy is to be seen as an emotionally traumatic major life event which leads to severe posttraumatic stress response and intense grief reactions that are still detectable some years later.

Abortion, Eugenic↗
PubMed2004

Maternal posttraumatic stress response after the birth of a very low-birth-weight infant.

OBJECTIVE: For parents, the premature birth of a child represents a traumatic event for which they are poorly prepared. To date, the focus of scientific interest has been on maternal psychological stress responses, such as anxiety and depression, or on appropriate coping mechanisms, whereas only scant attention has been paid to the traumatic aspect of the maternal experience after very low-birth-weight (VLBW) birth. The present study is the first to investigate the posttraumatic stress response of mothers after the birth of a VLBW infant in a prospective longitudinal study. METHODS: Fifty mothers of VLBW infants were examined at four measuring time points (1-3 days pp, 14 days pp and 6 and 14 months pp) with respect to posttraumatic symptoms [Impact of Event Scale (IES-R)], psychiatric diagnosis (SKID I for DSM-IV) and the extent of depression [Beck Depression Inventory (BDI) and Montgomery Asberg Depression Scale (MADRS)] and anxiety [State-Trait Anxiety Inventory (STAI) and Hamilton Anxiety Scale (HAMA)]. The control group comprised a group of 30 mothers after the uncomplicated spontaneous birth of a healthy child. RESULTS: At all four measuring timepoints (except 6 months pp), the mothers of the premature infants recorded significantly higher values for traumatic experience and depressive symptoms and anxiety compared with the controls. In contrast to the mothers in the control group, the mothers of the premature infants displayed no significant reduction in posttraumatic symptoms (IES-total), even 14 months after birth. CONCLUSION: The results indicate that the situation of a mother who has given birth to a VLBW infant is a complex, with long-term traumatic event necessitating ongoing emotional support extending beyond the period immediately after the birth.

Adult↗
PubMed2004

Membrane-bound delta-4 notch ligand reduces the proliferative activity of primitive human hematopoietic CD34+CD38low cells while maintaining their LTC-IC potential.

To examine the role of the Notch ligand Delta-4 on hematopoietic stem cells, human CD34+CD38low cord blood cells were cocultured on S17 cells transduced with transmembrane Delta-4 (mbD4/S17) or an empty vector (C/S17). By the end of a 3-week culture, mbD4/S17 induced a 25-fold reduction in nucleated cell production, as compared to C/S17, by maintaining a higher proportion of cells in G0/G1 phase. A specific retention of a high proportion of CD34+ cells throughout the culture was observed with mbD4/S17, contrary to C/S17. Although mbD4/S17 promoted expansion of cells with the phenotype of committed lymphoid precursors (CD34+CD7+CD45RA+), these cells still retained their myeloid differentiation potential. mbD4/S17 maintained a higher LTC-IC frequency in output CD34+ cells, compared to C/S17, as in the subsets of cells having completed the same number of divisions on mbD4/S17. A Delta4-Fc protein (extracellular part of human Delta4 fused to Fc human IgG1 portion), immobilized on plastic, also reduced cell production and retained the LTC-IC potential. Transplantation of cells grown on mbD4/S17 into NOD/SCID mice showed no significant enhancement of the long-term repopulating ability. Thus, Delta4 appears to inhibit hematopoietic stem cell proliferation, in association with the maintenance of short-term lymphoid and myeloid repopulation capacity.

ADP-ribosyl Cyclase↗
PubMed2004

WKY/Ztm-ter: a new rat inbred strain on the WKY/Ztm genetic background with congenital teratomas.

We describe a new rat model for teratomas (WKY/Ztm-ter) which arose through a spontaneous mutation in the inbred WKY/Ztm rat strain. When the tumours of the gonads became clinically apparent, affected males were 14 to 224 days of age, whereas the females only developed tumours between days 21 and 63. Tumour incidence is not gender-dependent. However, almost all females develop bilateral tumours, while 50% of the males show unilateral tumours. Histologically, all examined tumours (n = 65) represent partially undifferentiated teratocarcinomas.

Animals↗
PubMed2004

Orthotopic transplantation of rat ovaries as a tool for strain rescue.

Spontaneous mutations in inbred strains provide valuable resources for new disease models. Unfortunately, these mutations may affect reproduction, which require considerable efforts in breeding management. We transplanted ovaries of such mutant rat strains orthotopically into ovariectomized premature coisogenic recipients. A reproductive cycle was established in each of the recipients within 5 to 6 weeks after transplantation. Moreover, one-third became pregnant and had litters an average of 3 months after transplantation. These experiments demonstrate that orthotopic transplantation of ovaries can be used in the management of subfertile rat colonies.

Animals↗
PubMed2002

Comparison of tests for viable and infectious Cryptosporidium parvum oocysts.

The purpose of this study was to compare different assays for viable Cryptosporidium parvum incubated in water at a temperature commonly found in the environment. C. parvum oocysts were stored in sterile water for 9 months at 15 degrees C. A sample was removed monthly and analyzed by five different assays to determine oocyst viability. Mouse infection and cell culture showed that C. parvum oocysts remained viable and infectious when stored for 7 months at this temperature. Fluorescence in situ hybridization (FISH) using probes directed to ribosomal RNA was also applied to these oocysts. The proportion of FISH-positive oocysts was 70-80% for the first 2 months of storage, decreased and remained nearly constant at 40-50% for 3-7 months, then decreased to 20% by 8 months, and to 0% by 9 months. Amylopectin content and mRNA for amyloglucosidase (CPAG), as measured by RT-PCR, decreased much more rapidly. By 3 months and for the remainder of the incubation period, amylopectin content was 20% of the original amount present in the oocysts. The CPAG RT-PCR signal at 3 months was 50% of that observed after 1 month storage, 20% at 4 months, and was not detected thereafter. Thus, results from cell culture and mouse infection assay exhibited the best agreement, the FISH assay showed modest agreement with these assays, and CPAG RT-PCR and the amylopectin assay displayed marginal agreement with the other three assays.

Amylopectin↗
PubMed2002

Pulmonary microbial infection in mice: comparison of different application methods and correlation of bacterial numbers and histopathology.

Many investigations have been performed in characterising experimental bacterial infections in the lung of mice using several pathogens. Robust experimental pulmonary infection models require a reproducible method of application with defined numbers of pathogens to the respiratory tract without contaminating extrapulmonary tissues. At the same time trauma due to the experimental procedure should be kept to a minimum. So far several routes of administration have been used but a systematic comparison of these methods is still missing. Here we provide a comprehensive evaluation of view controlled i.t. instillation, tracheotomy, intranasal application, blind instillation and aerosol infection. An infection dose of up to 5 x 10(4) bacteria (L. monocytogenes) was applied to a group of ten mice by each technique and the animals were killed after 1 h or 24h. The number of viable bacteria was estimated by plating homogenates of the lungs and spleens. In addition, pathological effects on lung tissue were examined by histology 24h after infection. The highest reproducibility was achieved after applying Listeria directly in the trachea under view or by tracheotomy. However, mice were severely affected in their vitality after tracheotomy. Thus, for topical application of bacterial suspension into the lung the view controlled i.t. instillation is most appropriate.

Animals↗
PubMed2001

Fusobacterium equinum sp. nov., from the oral cavity of horses.

Two strains of gram-negative, anaerobic, non-sporulating rod that were isolated from the normal oral cavity and oral-associated disease from horses and which phenotypically resembled Fusobacterium necrophorum were characterized by sequencing of the 16S rRNA gene, phylogenetic analysis, DNA-DNA hybridization and phenotypic characterization. The results placed the novel strains as distinct members of the genus Fusobacterium. The novel species Fusobacterium equinum sp. nov. is proposed, with strain VPB 4027T (= NCTC 13176T = JCM 11174T) as the type strain.

Animals↗
PubMed2000

A multiple transgenic mouse model with a partially humanized activation pathway for helper T cell responses.

Mice expressing human CD4 and human MHC II molecules provide a valuable model both for the investigation of the immunopathogenetic role of human autoantigens and for the development of therapeutic strategies based on modulating helper T cell activation in vivo. Here we present a novel mouse model expressing HLA-DR17 (a split antigen of HLA-DR3) together with human CD4 in the absence of murine cd4 (CD4/DR3 mice). Human CD4 accurately replaces murine cd4 within T cells. In particular, the preservation of cd8(+) and CD4(+) T cell subsets distinguishes CD4/DR3 mice from other multiple transgenic models in which the alternative T cell subsets are fundamentally disturbed. Moreover, human CD4 is also faithfully expressed on antigen presenting cells such as dendritic cells and monocyte/macrophages, so that the overall transgenic CD4 expression pattern resembles very closely that of humans. HLA-DR3 expression in the thymus correlates very closely to that of mouse MHC II. In contrast, only 70% of mouse MHC II positive cells in spleen, lymph node, and peripheral blood coexpress HLA-DR3. No significant bias was found with regard to particular leucocytes in this respect. The stimulation of helper T cells clearly depends on the interaction between the human transgene products, since mAbs to HLA-DR and/or CD4 completely blocked in vitro recall responses to tetanus toxoid. CD4/DR3 mice represent a partially humanized animal model which will facilitate studies of DR3-associated autoimmune responses and the in vivo determination of the therapeutic potential of mAbs to human CD4.

Animals↗
PubMed2000

Isolation and characterization of the notch ligand delta4.

Notch signaling plays a critical role in a variety of developmental programs. In vertebrates, the complexity of the process is underscored by the existence of multiple Notch receptors and multiple ligands, each of which displays a distinct expression profile. Furthermore, the ligands can be subdivided into two families, the Serrate/Jagged family and the Delta family. Here we present the isolation of a novel Notch ligand, Delta4. Expression analyses indicate that mouse Delta4 is highly expressed in the eye and lung during embryogenesis and in the heart, lung, liver, and kidney of the adult. Functionally, Delta4 is indistinguishable from Jagged1 in its abilities to inhibit myogenesis and to stimulate transcription through Notch1 and the DNA binding protein CSL.

3T3 Cells↗
PubMed1999

A thrombopoietin receptor mutant deficient in Jak-STAT activation mediates proliferation but not differentiation in UT-7 cells.

Thrombopoietin (TPO) stimulates proliferation and differentiation of cells of the megakaryocytic lineage. It exerts its function by binding and activating c-mpl, a member of the hematopoietic receptor superfamily. Upon binding of TPO to its receptor, numerous signaling events are triggered. These include activation of the Jak-STAT (signal transducers and activators of transcription) pathway, mitogen-activated protein kinase (MAPK), Tec, and phospatidylinositol (PI) 3-kinase and phosphorylation of Shc and Vav. The contribution of different signaling pathways to the induction of specific cellular processes such as proliferation and differentiation is incompletely understood. We have previously described a mutant of c-mpl that fails to activate the Jak-STAT pathway but nevertheless retains its ability to mediate proliferation and activation of most signaling events in the murine hematopoietic precursor cell lines BAF/3 and 32D. We confirm here the ability of this mutant to mediate proliferation in the absence of Jak-STAT activation in the human cell line UT-7 and further show that this mutant fails to mediate TPO-induced megakaryocytic differentiation. Comparison of the signaling capacity of this mutant in UT-7 and BAF/3 cells shows considerable cell-type-specific differences. Whereas in BAF/3 cells the mutant still mediates activation of Shc, MAPK, Vav, and PI 3-kinase at levels comparable to the wild-type receptor, these events are strongly diminished in UT-7 cells expressing the mutant. Furthermore, we show that the C-terminal 25 amino acid residues of the receptor mutant are crucial for the mitogenic response in UT-7 cells.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Carnobacterium inhibens sp. nov., isolated from the intestine of Atlantic salmon (Salmo salar).

Strain K1T, isolated from the gastrointestinal tract of Atlantic salmon (Salmo salar), has the capacity to inhibit the growth of the fish pathogens Vibrio anguillarum and Aeromonas salmonicida. Strain K1T is a motile Gram-positive psychrophilic rod that lacks both catalase and oxidase, which does not grow on acetate containing media, but grows at pH 9 and in TSB with up to 6% sodium chloride content. Strain K1T is facultatively anaerobic and tryptone as a sole source of nutrient promotes growth. The most abundant cellular fatty acid of strain K1T is oleic acid (18:1cis9). Based on 16S rDNA sequence comparisons, it is suggested that strain K1T is phylogenetically closely related to C. alterfunditum. However, the unique phenotypic attributes of strain K1T suggest that it represents a new species. The name Carnobacterium inhibens is proposed, for which the type strain is K1T (= CCUG 31728T).

Aeromonas↗
PubMed1998

The use of a ribosomal RNA targeted oligonucleotide probe for fluorescent labelling of viable Cryptosporidium parvum oocysts.

A fluorescence in situ hybridization (FISH) technique has been developed for the fluorescent labelling of Cryptosporidium parvum oocysts in water samples. The FISH technique employs a fluorescently labelled oligonucleotide probe (Cry1 probe) targeting a specific sequence in the 18S ribosomal RNA (rRNA) of C. parvum. Hybridization with the Cry1 probe resulted in fluorescence of sporozoites within oocysts that were capable of excystation, while oocysts that were dead prior to fixation did not fluoresce. Correlation of the FISH method with viability as measured by in vitro excystation was statistically highly significant, with a calculated correlation coefficient of 0.998. Examination of sequence data for Cryptosporidium spp. other than C. parvum suggests that the Cry1 probe is C. parvum-specific. In addition, 19 isolates of C. parvum were tested, and all fluoresced after hybridization with the Cry1 probe. Conversely, isolates of C. baileyi and C. muris were tested and found not to fluoresce after hybridization with the Cry1 probe. The fluorescence of FISH-stained oocysts was not bright enough to enable detection of oocysts in environmental water concentrates containing autofluorescent algae and mineral particles. However, in combination with immunofluorescence staining, FISH enabled species-specific detection and viability determination of C. parvum oocysts in water samples.

Animals↗
PubMed1998

[Effects of para- and diamagnetic materials in a 1.5 Tesla high field magnetic resonance tomography system].

This article shows the results of an experimental investigation of the interference by paramagnetic and diamagnetic materials on imaging in a closed 1.5 Tesla high field magnetic resonance imaging system (MRI). For different types of sequences (SE, GE, EPI) the effects of metal and non-metal profiles in producing artefacts were investigated. A phantom (plastic trunk) filled with Gd-Mn-solution was used for representation of the artefacts. The materials analysed were placed parallel to the phantom at predetermined distances. The images were obtained in transverse and sagittal planes and analysed with respect to the resulting artefacts. The results show that aluminum and polymer profiles produce the weakest artefacts, even when the material is positioned close to the phantom. A comparison of the sequence types shows that the SE-sequence has a low sensitivity to artefacts, despite the great profile variation in size and shape. The SE-sequence accordingly showed a higher imaging stability as compared with the GE- and EPI-sequences. Steel and copper produced the strongest artefacts. The examination was begun after an intensive study of the literature (Internet, Medline, Meditec). So far have been few publications on this subject.

Artifacts↗