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Biomedical subjects

W Hein

Publications and source records attributed to W Hein.

At least 19 recordsLinked to original sources
PubMed2000

Cloning non-transformed sheep B cells.

The capacity to clone B cells and establish permanent B cell lines has greatly facilitated a wide variety of studies characterising the growth, differentiation, and gene expression of murine and human B cells. Similar investigations of B cell biology for other species have been severely restricted by an inability to culture or clone B cells. This is the first report of a method to clone non-transformed sheep B cells using a culture system based on murine CD154 and a combination of human gamma chain-common cytokines. Sheep Peyer's patch B cells were cultured for 120 days and then cloned by limiting dilution culture. The parental B cell culture contained both surface immunoglobulin (sIg)M(+) and sIgG1(+) B cells and both types of B cell were cloned. Clonality was confirmed by PCR analysis of Ig heavy chain (HC) and light chain (LC) expression and DNA sequencing of HC V genes. There was agreement between the PCR and flow cytometric analyses of HC isotype expression on the B cell clones but the available monoclonal antibodies specific for sheep lambda and kappa LC did not react with all clones. Soluble Ig was detected in the culture supernatant of sIgG1(+) clones but not sIgM(+) clones. The B cell clones remained dependent upon CD154 and gamma chain-common cytokine co-stimulation for sustained growth and maintained stable Ig expression. The cloning of non-transformed sheep B cells should provide a valuable tool for studying sheep B cell biology, establishing Ig HC- and LC-specific monoclonal antibodies, analysing the B cell Ig repertoire, and may be used to produce sheep monoclonal antibodies.

Animals↗
PubMed2000

[Effect of ion channel modulators on the membrane potential of human chondrocytes].

As all living cell systems, human chondrocytes are provided with a membrane potential. For its origin the existence of ion channels at the cell membrane is an essential prerequisite. In non-human chondrocytes, different ion channels could already be identified. A connection between the potassium channel activity and the proliferation has been detected in different human cell systems. Whereas, the proof of a connection between ion channel activity of human chondrocytes and the proliferation has yet to be established. In this study the concentration-dependent influence of the ion channel modulators tetraethylammonium (TEA), 4-amino-pyridin (4-AP), 4',4'diisothiocyanatostilbene-2,2'disulfonic acid (DIDS), 4-acetamido-4'isothiocyano-2,2'disulfonic acid stilbene (SITS) and verapamil on the membrane potential and the proliferation of human chondrocytes was investigated using flow cytometry. The results show an effect of the used ion channel modulators causing a change of the membrane potential of human chondrocytes. The decrease of the membrane potential by 18% was measured with 0.25 mmol/l verapamil meaning the maximal measurable effect compared with a control group. When measuring DNA distribution, it became apparent that the human chondrocytes are diploid cells with a very low proliferation tendency. These results allow the conclusion of an influence of ion channel modulators on chondrocyte proliferation.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2000

Results of arthroscopic joint debridement in different stages of chondromalacia of the knee joint.

A retrospective study was performed of 161 patients who had undergone arthroscopic operation for chondromalacia of the knee joint. After an average follow-up period of 40 (range 10-72) months, patients with severe articular cartilage lesions who had undergone articular lavage alone showed significantly poorer results (P < 0.001). With the same stage of chondromalacia and having undergone the same surgical procedure, younger patients showed better results than older patients. The more effective interruption of the circulus vitiosus during the development of degenerative joint diseases is the primary cause for better results achieved by mechanical debridement of the joint for patients suffering from grade 2 or higher. According to the literature, aggressive subchondral abrasion in severely degenerated knees does not show any benefits. Apparently, the success of the therapy depends to a great extent on the inferiority of the potential degenerative regenerate (lack of capacity of intrinsic regeneration of the hyaline cartilage) as well as on the grade and the progression of chondromalacia. Almost every second patient suffering from grade 4 chondromalacia complained of recurrent pain 1 year postoperatively. One of every 6 patients received a knee joint prosthesis within the 1st year. Therefore, the patients' preoperative expectations have to be clearly objectified. The surgical procedure as an operation with a low complication risk can also be justified as a temporary alternative to total knee arthroplasty in patients suffering from a high-grade degeneration of the joint.

Adult↗
PubMed1999

[Results of the Elmslie-Trillat procedure in cases of patella(sub)luxation related to chondral pathology].

Between May 1981 and December 1993, 120 patients (126 knee joints) were operated using the Elsmlie-Trillat procedure because of patella(sub)luxation. 79 patients were reviewed at an average follow up of 4.1 (1-13.6) years. 46 women and 33 men were operated with an average age at operation of 26.9 (14-59) years. The examination included Bentley's Score, radiological parameters (e. g. grading of patella dislocation), grading of chondromalacia and patient characteristics (e. g. age, pre-operative time). 64 knee joints (70. 3 %) were evaluated 'very good' and 'good', using the score of Bentley. There were significantly worse results in cases with higher grading of chondromalacia (p <0.0036), longer pre-operative time (p < 0.012) and older patients (p < 0.0023). The worst and most highly significant results were in these patients with prior knee surgery (p < 0.0001). A good patella relocation correlated with improved results (p < 0.001). There was no difference in cases with patella dislocation and/or patellasubluxation. In conclusion, the Elmslie-Trillat procedure should be carried out 'in the correct manner and at an early stage'. To optimise the therapy in cases of patella dislocation the high number of operation techniques should be analysed and used regarding risk groups.

Adolescent↗
PubMed1998

Caprine T-cell receptor variable beta-chain (TCRV beta) repertoire analysis and potential applications in cowdriosis immune response studies.

Anchor polymerase chain reaction has been applied to the study of caprine TCR V beta-chain repertoire at the mRNA level in peripheral blood of a Saanen goat. Single stranded, g-tailed cDNA synthesized from total RNA was PCR-amplified using a sheep V beta constant region primer (3') and a poly(dC) anchor primer (5') at the variable region end of the TCR V beta-chain. The obtained amplicon was subsequently cloned into Bluescript plasmid vector. A total of 72 recombinant clones whereof 61 contained an insert of appropriate size were harvested. Up to now, the full length sequences of a total of 55 clones have been obtained. Nine clones were rearranged but not functional due to stop codons. Forty-five sequences were functionally rearranged and further analyzed. They were classified into 15 different V beta families on the basis of V-region sequence homology with their human counterpart. V beta families corresponding to the 9 published bovine families were represented in our library. This complexity enables us to develop V beta family-specific primers in order to study the TCR V beta repertoire of other goat breeds of interest, i.e., the Creole goat. There the TCR V beta repertoire analysis and kinetic study of the cowdriosis model will provide insight into the type of the immune response and the status of protection during the immunization process and challenge.

Animals↗
PubMed1998

Biomechanical and densitometric bone properties after callus distraction in sheep.

Assessment of biomechanical stability of diaphyseal bone lengthened by callus distraction is an unsolved problem. A middiaphyseal corticotomy was performed in the left tibia of 24 sheep. After 7 days, callus distraction was begun at a rate of 0.5 mm every 12 hours for 30 days using a standard unilateral fixator system. Animals were euthanized 4, 8, or 12 weeks after the end of distraction. The lengthened tibia and the contralateral control tibia from each animal were evaluated by radiographic, densitometric (dual energy xray absorptiometry, quantitative computed tomography), and biomechanical (axial compression testing, torsion testing to failure) methods. The bone mineral density and maximum torque for the lengthened tibia were significantly greater in the 8-week group than in the 4-week group. However, the values in the 12-week group were significantly smaller than in the 8-week group. In the lengthened tibias, there was a correlation between the maximum torque and the bone mineral density, and between the maximum torque and the bone density. Bone density measurements are useful prognosticators for the safe removal of external fixators after leg lengthening procedures. By using these methods, clinical fractures after leg lengthening could be avoided in the future.

Absorptiometry, Photon↗
PubMed1998

[Possibilities of follow-up imaging after implantation of a carbon fiber-reinforced hip prosthesis].

INTRODUCTION: There are many problems in the radiological diagnosis of aseptic loosening in total hip arthroplasty. Computed tomography (CT) and magnetic resonance tomography (MRT) are not usable for metallic implants (stainless steel, cobalt alloy, titanium alloy). MATERIAL AND METHODS: From April 1993 to December 1993 15 CFRP non-cemented hip prostheses have been implanted. In a prospective clinical study plane radiographs, CT and MRT have been analysed. RESULTS: Three stems were revised (1 femoral fracture, 1 severe thigh pain, 1 aseptic loosening). CFRP are not visible in plane radiographs. There was a complete (two-third of the cases) or nearly complete (one-third of the cases) small sclerotic interface between the prosthesis and the bone, these were apparent in CT and MRT in stable implant cases and did not have any clinical correlations. DISCUSSION: The small sclerotic interface is quite different in comparison to so called "Reactive Lines". In one case of aseptic loosening there was an interposition of soft tissue between prosthesis and bone in MRT and CT. CFRP inaugurates new diagnostic possibilities in aseptic loosening of hip prosthesis and in tumour surgery too.

Aged↗
PubMed1996

Dega acetabuloplasty combined with intertrochanteric osteotomies.

Between 1973 and 1984, 70 modified Dega acetabuloplasties done simultaneously with intertrochanteric osteotomies in 51 patients with developmental dysplasia of the hip were reviewed for long-term results and analyzed for causes of failure. Mean patient age at operation was 2.9 years (range, 8 months-8 years), and mean followup time was 15.2 years (range, 10-19 years). Topical investigations were based on clinical criteria of the Severin classification and radiologic criteria of the Commission for the Study of Hip Dysplasia of the German Society of Orthopaedics and Traumatology. The review of clinical documents and investigations very good and good results in 80% of the hips. The Trendelenburg sign was a useful clinical indicator for problematic cases. Measurements on radiographs were classified into deviation grades from the normal range. Values of the acetabulum and the acetabulum to head relation were normal or slightly abnormal in >80% of hips. Measurements of the femoral head and neck were in the low normal range. The lowest percentage of normal values was in 24 cases with coxa valga after acetabuloplasty combined with derotational varus osteotomy. Poor clinical and radiologic outcome usually was the result of avascular necrosis of the femoral head or recurring valgus deformity after derotational varus osteotomy. The rate of avascular necrosis as a consequence of the operation was 5.7%. The risk of avascular necrosis caused by derotational varus osteotomy is lower than the risk of later development of deformities in the proximal femur.

Acetabulum↗
PubMed1996

Tibial lengthening. Epiphyseal and callus distraction compared in 39 patients with 3-14 years follow-up.

We examined 32 patients with 39 lengthenings (mean 8 cm) of the lower leg 3-14 years postoperatively. 23 distraction epiphyseolyses and 16 corticotomies with callus distraction had been carried out using the llizarov system. Both procedures yielded the same healing indices and the number of problems and complications was the same in the two groups. After distraction epiphyseolysis, serious complications of the knee and greater deviations from the normal leg axis were commoner than after callus distraction, which we now prefer.

Adolescent↗
PubMed1995

Hydroxyapatite-coated hip prostheses. Early results from an international study.

A hydroxyapatite-coated hip prosthesis designed to stimulate proximal femoral stress transfer was studied in 222 patients undergoing primary total hip arthroplasty with a minimum followup of 2 years. The femoral component was a roughened titanium alloy with a 50-mu coating of hydroxyapatite applied to the proximal third. A proximal press-fit technique was applied with distal femoral over-reaming as standard procedure. The hydroxyapatite-coated acetabulum was of hemispherical design. Analysis of the clinical results showed a mean Merle D'Aubigné score of 16.7 points at 6 months and 17.4 points at 2 years. Mild residual thigh pain of unknown origin was reported in 3.6% of patients at 2 years. Radiographic evaluation showed complete acetabular and proximal femoral osseointegration without any loosening. No radiolucency or reactive line formation was observed around the hydroxyapatite-coated areas of the prostheses. Femoral bone densification occurred at the coated-uncoated transition zone (54%); 4% to 6% of cases showed cortical hypertrophy at the uncoated area of the stem. Reactive lines were seen around the distal stem in 52% of patients after 2 years. The clinical outcome was excellent, and the radiographic data pointed mainly to proximal femoral stress transfer.

Adult↗
PubMed1993

Contribution to some phenotypical characteristics of Vibrio cincinnatiensis. Studies in one strain of a diarrhoeic human patient and in two isolates from aborted bovine fetuses.

Until now, only a few strains of V. cincinnatiensis have been isolated. This study describes a further three isolates which originated in one case from a stool specimen of an immunocompromised elder patient suffering from enteritis and in two cases from the rennin stomachs of aborted bovine fetuses. These strains grew on TCBS, CIN, MacConkey and XLD plates. Their biochemical activities were dependent on NaCl concentration, in particular the formation of indole, lysine and ornithine decarboxylases, arginine dihydrolase, the reduction of nitrate and behaviour in the Voges-Proskauer test. Moreover, lysine decarboxylase and nitrate reductase were temperature-dependent. The knowledge of these hitherto unknown phenotypical characteristics may facilitate the diagnosis of the pathogen.

Abortion, Veterinary↗
PubMed1991

The intestinal habitat for organized lymphoid tissues in ruminants; comparative aspects of structure, function and development.

Unlike the Peyer's patches of rats and mice, which are considered to be secondary lymphoid organs, the ileal Peyer's patch of sheep is thought to be responsible for the primary generation of B cells, like the bursa of Fabricius of birds. The ileal Peyer's patch of sheep shows prenatal maturation, antigen-independent lymphopoiesis, a rate of lymphocyte production larger than that of the thymus, and involution at a young age. Follicles contain few T cells and have an IgM+, relatively immature B lymphocyte population, as judged by B-cell differentiation markers. The follicle-associated epithelium of the ileal Peyer's patch is of a special type that sheds carbonic anhydrase-rich, 50-nanometer membrane-bounded particles (carbonic anhydrase-reactive particles; CAP) into the intercellular spaces. The CAP filter into the follicle centre and are taken up by lymphocytes. They represent the epithelial (bursa-like) element in an otherwise mesenchymal stroma of reticular cells embedding the follicle lymphocytes. Transepithelial transport of macromolecules, with the formation of multivesicular body-like cytoplasmic vacuoles, appears to be the basis for CAP formation. The jejunal Peyer's patches are devoid of CAP, persist in the adult animal, contain M cells with clusters of B cells in the follicle-associated epithelium, and have many CD4+ lymphocytes in the follicles and in the interfollicular areas. Aggregates of lymphoid follicles in the large intestine resemble the jejunal Peyer's patches with respect to their lymphocyte population and the ileal Peyer's patch with respect to their follicle-associated epithelium.

Animals↗
PubMed1990

Class I major histocompatibility complex cDNA clones from sheep thymus: alternative splicing could make a long cytoplasmic tail.

To investigate the class I major histocompatibility complex (MHC) genes expressed in the young sheep thymus, a cDNA library was screened with a human HLA-B7 cDNA probe under conditions of relaxed stringency. Thirteen clones were isolated and found by partial sequences to fall into five classes, requiring the expression of at least three loci. One sequence was found six times, almost half of the total, and may thus represent the major message expressed in the young sheep thymus. One of the clones was found to have failed to excise the intron between cytoplasmic exons 7 and 8, leading to the predicted synthesis of a cytoplasmic domain 23 amino acids longer than the other sheep sequences, and 15 amino acids longer than any cytoplasmic domain previously described. The sequences of all the clones were found to be most similar to bovine, and least similar to mouse class I MHC sequences.

Amino Acid Sequence↗
PubMed1990

[Modification of lipoxygenase products in bone by the linoleic acid content of the diet].

Eicosanoids are supposed to participate in the regulation of bone metabolism. 30 male white rats of the wistar strain were fed on a diet rich in linoleic acid (LA), on a diet poor in LA and on a pellet diet after 3 month up to an age of 5 month. The formation of leukotrienes (LT) C4, D4, and E4 from the proximal tibia metaphysis after LA rich diet has been compared to the formation from LA poor and pellet diet. LA rich diet increased the formation of LTC4, D4 and E4 in the proximal tibia metaphysis. The properties of eicosanoids as local mediators in the bone were discussed.

Animals↗
PubMed1990

[The surgical treatment of knee joint extensor muscle contractures].

It is reported about the results after operative mobilization of knee joint in 19 patients with contractures of extension muscles of knee joints. After operative arthrolysis and/or Payr-Plasty the range of motion has increased on average from 23 degrees to 92 degrees (a relative gain of 52%). Patients with traumatic knee contracture of extension muscle achieved an improvement in the range of movement on average by 76 degrees, whereas those with contracture due to infection improved on average by only 43 degrees. The etiology, the duration, and the preoperative loss of movement are important for success of treatment.

Adult↗
PubMed1990

[Changes in the spongiosa density in the femoral head of rabbits in atherosclerosis].

Modulations of spongiosa density in the femoral head of rabbits by atherosclerosis. In a long-term study 31 rabbits (+5 control animals) were fed about 20 weeks on a diet rich in cholesterol. An important observation in this study was, that spongiosa density in the femoral head decreases after cholesterol rich diet in contrast to the control group. This effect could be modulated by the Trapidil AR 12463 content (50 mg/die) of the diet, but not by the high density lipoprotein application. Serum cholesterol levels and induced atherosclerosis were determined. Correlations between spongiosa density and atherosclerosis were discussed.

Animals↗