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Biomedical subjects

U Weber

Publications and source records attributed to U Weber.

At least 217 records · Page 12Linked to original sources
PubMed1980

Met-enkephalin-like immuno- and bioreactivity in extracts from skin containing Merkel cells.

Skin from the upper lip, bearing the sinus hair follicles rich in Merkel cells was investigated in guinea pig, rat, cat and rabbit by radioimmunoassay and radioreceptor assay. In all species Met-enkephalin-like immunoreactive material was extracted. In guinea pig this material had the same molecular size as Met-enkephalin. In a radioreceptor assay made with rat brain membranes extracts of guinea pig skin caused displacement of [3H]Met-enkephalin. The endogenous opioid of the size of Met-enkephalin contained in these skin extracts possibly derives from the Merkel cells.

Animals↗
PubMed1980

[Secondary vascular disease in spondylolisthesis].

The topographic relation of the spine to the great vessels let to the expectation that spondylolisthesis may lead to mechanical irritation of the cauda equina as well as of the great vessels. The angiological examination of 223 patients with spondylolisthesis of the lumbar spine shows that the changes in the anatomy of the great vessels are less significant than expected after experiments involving artificial dislocations of the spine in cadavers. In vivo arterial function is not altered even in true spondyloptosis. Pelvic veins on the other hand show considerable compression and diminished flow in third and fourth degree spondylolisthesis of L5 over S1 as well as in second degree spondylolishtesis of L4 over L5. These patients seem to be disposed to venous disorders involving varices and thrombosis. If therefore a high venous pressure is found and a ventral fusion proposed it should be discussed to combine the procedure with a decompression of the veins.

Humans↗
PubMed1979

Familial centronuclear myopathy: a haploid DNA disease?

In the same family three boys (ages 8, 11, 14 years), suffering from a slowly progressive weakness of the flexors of the head and distal muscle groups of the extremities, were found to have a myopathy characterized by the presence of central nuclei in type I fibres. Their mother showed no histopathologic signs but a myopathic pattern on electromyography could be demonstrated. Cytophotometric examination of the anterior tibial muscle of these siblings revealed a reduction in DNA content by 50% in the central and subsarcolemmal nuclei (haploid DNA content) when compared with subsarcolemmal nuclei (diploid DNA content) of the same muscle of their mother. Nuclear DNA concentration in fibrocytes did not differ significantly between members of the family. Therefore, it is assumed that the nuclei of muscle fibres are selectively affected by the disease process which is indicated by a haploid DNA content.

Adolescent↗
PubMed1979

[Benign solitary enchondroma (author's transl)].

Solitary enchondroma is a benign bone tumor with a doubtful prognosis changing by topical but not by clinical, roentgenological or histological characteristics. Therefore benign solitary enchondroma should be subdivided in such of peripheral and such of central localisation. Both forms of enchondroma normally show an asymptomatic development. Diagnostic problems occur in central enchondroma because of its radiological, angiographical and szintigraphical aspects. Peripheral enchondroma should be treated by local excision. Recurrences after local treatment are extremely rare. In treatment of central enchondroma bone resection should be performed following common principles of onkological radicality. Local excision is not sufficient; amputation should be reserved for treatment of chondroma close to the trunk or chondrosarcoma.

Bone Neoplasms↗
PubMed1979

[The motility of hip joint endoprostheses (author's transl)].

The motility of a healthy hip joint normally seems to be better than the motility of an endoprosthesis. The movement of all models of endoprostheses must fulfill minimum requirements as well in total motility as in each way. The arithmetical investigation of the motility of commercial total endoprostheses shows good locomotion for most cases. Decisive is the relation between prosthesis head- and prosthesis neck diameter. Insufficient motility of endoprosthetic models results if especial--redundant--constructive details of the socket are selected. It seems to be more problematical to produce double cup endoprostheses which reveal sufficient function. Normally the motility of double cup prostheses must be essentially less than that of total endoprostheses or of a healthy hip joint. A special implant technique and various constructive assumptions are necessary to reach a sufficient functional result.

Biophysical Phenomena↗
PubMed1979

Carbon as an implant material in orthopaedic surgery.

Carbon is a material of proven value in many fields of medicine. It has only minor reactions compared with other materials, but does have unfavourable mechanical characteristics. New kinds of carbon with similar physical characteristics to other materials, e.g. steel and ceramic, have now been developed.

Animals↗
PubMed1979

[The use of carbon as manufacturing material of endoprotheses (author's transl)].

According to the present stage of technology, arthroplasties have a change of only short-term to medium-term success quotas despite good initial successes. Permanent healing is restricted because of possible loosening of the prostheses. Even clinically silent loosenings will ultimately lead to failures, either by progressive degeneration of the bones at the supporting points of the prosthesis or through breakage of the stem of the prostheses. Attempts to overcome such difficulties by changing the shape of the prostheses, remain unsuccessful. The material employed in the construction of the prosthesis is certainly of some importance in this connection. Carbon has been known for a long time as a well-tolerated material in implant surgery. Carbon is indeed distinguished by high biocompatibility. The development of new carbons based on graphite which considerably improve its physical properties, has enabled the manufacture of endoprostheses made from carbon. Studies have proved that this substance is nontoxic. There are also no immunological reactions. Abrasion is low, and the abraded particles do not produce any severe inflammatory reactions. Hence, prostheses made from carbon can be employed as combination constructions, using suitable types of carbon in accordance with the required functions.

Biocompatible Materials↗
PubMed1978

[Transplantation of periosteum-coated cortical and cancellous bone grafts for treatment of fractures and pseudarthrosis (author's transl)].

Bone grafts are used in the treatment of fractures just as in the treatment of atrophic pseudarthroses of long tube bones. Only autologous bone graft is a reliable transplantation material. The discussion about different values of cancellous grafts and cortical-cancellous grafts is not completed yet. It will be reported about the own results of 110 transplantations of fresh and ununited fractures of long tube bones between 1968--1975. Only the autologous cortical-cancellous periosteum-coated single graft was used.

Femoral Fractures↗
PubMed1977

[Immunological aspects of syngenesioplastic bone transplantation in treatment of infantile bone tumors (author's transl)].

Bone transplantations are made often in the treatment of benign bone tumours or tumour like affections. Especially at the appropriate infantile illness the use of an autologous transplant may prove impossible. Homologous and heterologous osseous transplants are largely unsuitable, because of the induction of immunological reactions. So called syngenesioplastic transplants let expect a tolerance of the recipient organism. This is a report of the results of clinical, radiological and especially immunological follow-up-examinations of 11 patients treated from August 1974 to October 1976 with syngenesioplastic spongiosa transplantation.

Bone Cysts↗
PubMed1977

[Low-dose heparin and acetyl-salicylic acid after elective operations on the hip joint (author's transl)].

3.6 g acetylsalicylic lysin was injected into 30 patients daily after operative replacement of the hip-joint. Pulmonary embolism and (or) deep-vein thrombosis were diagnosed in 19 patients. Low-dose heparin (3 X 5000 IU/24 h) significantly reduced the incidence of deep-vein thrombosis (ten of thirty patients: P less than 0.05) compared with the acetylsalicylic acid group. The results demonstrate not only the inadequate thrombosis prophylaxis provided by acetylsalicylic acid, but also that low-dose heparin prophylaxis in these specially at risk patients is of limited efficacy.

Aged↗
PubMed1977

[Mechanical properties of carbon as implant material in orthopedic surgery (author's transl)].

Among others material problems are come to the fore in endoprothetic with growing biochemical knowledge, also because of the realisation that in different parts of the same prothesis functionally different mechanical demands must be set. Technological progress in carbon production has lead to the development of a spectrum of different carbon specialities with various mechanical properties. In orthopaedic surgery of endoprothetic high strengh isotropic carbon, impregnated carbon and fibrereinforced carbon-carbon-composites are of particular interest, because of their physical properties and unchanged favourable chemical and biological properties of carbon. Thereby it is on one side a question of carbon material with extraordinary tribological qualities, on the other side of carbons with nearly isoelastic behaviour towards the bone, respectively with equal quotient of breaking strength and young's modulus. Therefore in future the manufacture of components with functional approbiate material using the same basic material carbon seems to be possible for the production of endoprothesis with different working parts.

Biomechanical Phenomena↗