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Biomedical subjects

W Hein

Publications and source records attributed to W Hein.

At least 19 recordsLinked to original sources
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↗
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↗
PubMed1989

[Prostaglandins--local regulators in bone?].

Since the initial discovery by Bergström, prostaglandin E has been the focus of an intense research effort in vitro and in vivo. The regulation of bone resorption and formation involves local as well as systemic factors. In the last decade, prostaglandins have been found to be intimately associated with bone metabolism. One hypothesis consistent that osteoblastic c AMP levels play a central role in determining whether osteoblasts stimulate or inhibit osteoclastic bone resorption. The osteoinductive properties of prostaglandins were discussed.

Animals↗
PubMed1989

[The significance of Ilmaplant as a bone substitute with reference to prostaglandin biosynthesis in bones. An animal experiment-clinical study].

The paper pointed out the resorbable material Ilmaplant-R and the glass ceramic Ilmaplant-L which are used for bone substitution. X-ray, histomorphometric and total mineral contents study were carried out in the region of healing defects in the tibia of 60 male white wistar rats. The healing response of the two bioceramics was compared 12 weeks after implantation. The inductive properties of prostaglandins were discussed. The possibilities of clinical application of Ilmaplant-R were demonstrated on the basis of short-term results up to 12 months.

Animals↗
PubMed1989

[Our ideas for treatment of dislocated dysplastic hip in early childhood].

The early diagnosis and treatment of congenital dislocation of the hip cannot prevent the manifestation of luxation in every case. The following operative treatment should include not only the open reposition, but also all deformities of the upper femur and the acetabulum. This combined procedure is already possible in the infancy starting from the 6th month. The correction of increased antetorsion and CCD-angle alone respectively the increased acetabular angle is not indicated. The spontaneous normalization of the not operated part of the hip can be find only in a minimal part of cases. The stabilization of bone defect in the acetabuloplastic by Dega is performed by allogenic deep frozen cortico-cancellous bone grafts successfully.

Acetabulum↗
PubMed1989

[The possible role of occupational factors in influencing the manifestation of idiopathic femur head necrosis].

The idiopathic necrosis of the femoral head of adults is increasing. The disease appears in the age from 20 to 40 years and leads to the destruction of the femoral head. The final state is often a severe osteoarthrosis of the hip joint already in the efficient lifetime. The etiology of the idiopathic necrosis of the femoral head is not yet cleared up. There were only few information about possible professional factors. In a study the professional anamnesis of 153 patients were utilized. Thereby high portions of works with dynamic and static charges and expositions of vibrations were found.

Adult↗
PubMed1988

Recombinant human interferon alpha-2a: delivery to lymphoid tissue by selected modes of application.

The effect of different parenteral administration routes (i.d., s.c., i.v.), infusion rates, and albumin contents of the drug vehicle on the cumulative recovery of recombinant human interferon alpha-2a (rIFN alpha-2a) in lymph and on its concentration in blood and lymph was determined in sheep. Blood samples were withdrawn from a jugular vein catheter and lymph was collected from a cannulated efferent popliteal lymphatic duct. The concentration of rIFN alpha-2a in lymph and blood plasma samples was measured by an enzyme immunoassay. Following i.v. infusion of 2 x 10(7) U of rIFN alpha-2a, the peak concentrations measured in blood plasma and lymph, respectively, were 8250 and 14 U/ml. The concentration measured in lymph after i.d. or s.c. administration of the same dose was about 10(5) times higher (peak concentration, 3.1 x 10(6) U/ml), while blood plasma levels remained low (peak concentration, 315 U/ml). The cumulative recovery of rIFN alpha-2a in lymph following i.d. or s.c. administration was 59.2 +/- 7% (mean +/- SD; N = 8) and was affected neither by the infusion rate nor by the coadministration of albumin. Our data indicate that following i.d. or s.c. administration, rIFN alpha-2a (MW 19,000) is absorbed mainly by the lymphatics. This results in high levels of rIFN alpha-2a in the lymph which drains from the application site to the regional lymph nodes. The knowledge gained in this investigation may help to improve the mode of administration and therapeutic efficacy of protein drugs whose targets are lymphoid cells.

Absorption↗
PubMed1988

Correlations between endogenous prostaglandin E formation in the bone and spongiosa density.

The formation of prostaglandin (PG) E in the femoral head and the lumbar vertebral body of rats under ex vivo conditions after a linoleic acid (LA) rich diet (13.3 J%) has been compared to that of rats after an LA poor diet (0.5 J%). LA rich diet increased the formation of PGE in the lumbar vertebral body. In the femoral head were a similar, but statistically insignificant effect. The spongiosa density in the femoral head and the lumbar vertebral body increased after LA rich diet in contrast to LA poor fed rats. We conclude that the spongiosa density could be modulated by the LA content of the diet possible via alterations of endogenous PG biosynthesis.

Animals↗