PubMed Health⌕ Search

Biomedical subjects

J Neidel

Publications and source records attributed to J Neidel.

27 records · Page 2Linked to original sources
PubMed1988

Results of a bovine collagen vascular graft (Solcograft-P) in infra-inguinal positions.

A new bovine collagen prosthesis (SOLCOGRAFT P) was tested clinically. Previous biophysical and animal experiments had yielded promising results, including a modulus of elasticity closely resembling that of human arteries. Eighty-four prostheses were implanted in the femoro-popliteal and 20 in the femoro-infrapopliteal positions. While the cumulative patency rates were acceptable (86% after one year, 74% after two years, 69% after 3 years, and 59% after four years), the cumulative aneurysm rate was unacceptably high (2.2% after one year, 16.9% after two years, 36.6% after three years and 42.6% after four years). We comment on the reasons why the actual incidence of aneurysms in biografts has been underestimated in the past. The management of graft aneurysms and the remaining indications for reconstructive surgery with the SOLCOGRAFT P are also discussed.

Bioprosthesis↗
PubMed1986

Purification and characterization of collagenase activator protein synthesized by articular cartilage.

We have isolated an activator of collagenase from medium conditioned with articular cartilage. The activity is contained in an acidic protein appearing as a doublet band of Mr 57,000 and 56,000 on sodium dodecyl sulfate polyacrylamide gels. Both components of the doublet have identical isoelectric points as demonstrated by gel electrophoresis. Purified synovial collagenase has a high dependence on the presence of this factor for activity. Other known activators of latent proteolytic enzymes such as trypsin and mercurials will stimulate collagenase but only if activator protein is present. The activator protein is itself a latent metalloprotease because in the presence of p-aminophenylmercuric acetate and calcium it will digest casein. The caseinase activity and collagenase activation activity have identical heat inactivation profiles, both being stable to a temperature of 60 degrees C and partially inactivated at 80 degrees C. The synthesis of the activator is localized in the superficial zone of articular cartilage.

Animals↗
PubMedDate not supplied

[Percentile graphs in the documentation of acetabular angle in children with hip dysplasia. A tool in the diagnosis and quality control of its treatment].

The acetabular index (AI; Hilgenreiner 1925) has proven to be a reliable parameter for the radiological diagnosis of developmental hip dysplasia (DDH). Age-dependent normal values and ranges of the AI are well documented. These data, however, have so far not been presented graphically in a way which would have made them suitable for patient data documentation on a routine basis (calculation of percentiles, time-axis with log scale, smoothing). We have therefore created graphs meeting these requirements, based on a previous examination of the AI of 719 girls and 428 boys (Tönnis and Brunken 1968). These graphs have meanwhile proven to be a useful and time-saving tool for the diagnosis as well as quality control of the treatment in children with DDH.

Acetabulum↗
PubMedDate not supplied

[Practical significance of cytokine determination in joint fluid in patients with arthroses or rheumatoid arthritis].

OBJECTIVE: To determine whether the activity of cartilage-degrading enzymes in the synovial fluid (SF) of patients with rheumatoid arthritis and other joint diseases is correlated with the concentration of cytokines in the SF. METHODS: Cytokines and cartilage-degrading enzymes were determined in the SF of 97 patients with various disorders involving the knee joints (rheumatoid arthritis (RA) n 44; osteoarthritis (OA) n 35; meniscal trauma (Men) n 10; reactive arthritides (ReA) n 8). In these samples we measured the concentrations of interleukin-1 alpha and beta, IL-1-receptor antagonist (IL-1ra), IL-6, IL-8, tumor necrosis factor alpha (TNF alpha; all by ELISA), collagenase-activity and caseinase-activity (by substrate assays). RESULTS: With the exception of IL-1 alpha and IL-6, cytokine-concentrations were significantly higher in RA than in OA SF-samples (p < 0.05; ANOVA on ranks). IL-1ra, IL-6, and IL-1 beta were correlated best with the collagenase-activity in the SF (r = 0.63; 0.57; 0.55; Spearman's rank correlation), while IL-1 beta (r = 0.53) and IL-1ra (r = 0.52) were best correlated with the caseinase-activity in the samples. The SF-concentration of IL-1ra was well correlated with the levels of IL-6, IL-1 beta, II-8, and TNF alpha (r from 0.73 to 0.66; all p < 0.005), but not with IL1 alpha. The molar ratio of IL-1 to IL-1ra in the SF was neither correlated with the activity of collagenase nor caseinase. IL-1 beta and IL-1ra in the SF were positively correlated with the erythrocyte sedimentation rate (ESR). CONCLUSIONS: The determination of IL-1 beta and IL-1ra in the SF of patients with joint disorders as examined in this study seems to allow to a certain extent a prediction of the collagenase- and caseinase-activity contained in the diseased joint. We would favor.

Arthritis↗
PubMedDate not supplied

Changes in systemic levels of insulin-like growth factors and their binding proteins in patients with rheumatoid arthritis.

OBJECTIVE: To determine whether circulating levels of insulin-like growth factors and their binding proteins are altered in patients with adult onset rheumatoid arthritis. METHODS: Plasma-levels of insulin-like growth factor-I (IGF-I), IGF-II, IGF-binding-protein 2 (IGFBP-2), and IGFBP-3 were measured by radioimmunoassay in 53 patients with clinically active rheumatoid arthritis (RA) and in 51 control subjects. RESULTS: In RA patients plasma levels of IGF-II were lower (601 +/- 34 vs. 731 +/- 32 micrograms/L (mean +/- SEM); p = 0.005; Mann-Whitney rank sum test) than in age- and sex-matched controls (n = 30 per group). In contrast, plasma levels of IGFBP-2 (412 +/- 40 vs. 254 +/- 20 micrograms/L; p = 0.003) and IGFBP-3 were elevated in RA patients (3.34 +/- 0.19 vs. 2.87 +/- 0.21 mg/L; p = 0.019) as compared with the matched controls. The molar ratio of IGF-I to IGFBP-3 was significantly reduced in subjects with RA (0.18 +/- 0.01 vs. 0.24 +/- 0.02; p = 0.008). Furthermore, in RA patients plasma levels of IGFBP-2 were positively (r = 0.45), and levels of IGF-2 negatively (r = -0.45) correlated with circulating levels of C-reactive protein (p < 0.01 in both cases; Spearman rank correlation). CONCLUSION: Increased levels of IGFBPs in RA may result in the reduced availability of free IGFs that can bind to IGF receptors. The observed changes in the IGF system may thus participate in the catabolic processes in rheumatoid arthritis.

Adolescent↗
PubMedDate not supplied

Thyroid function in Legg-Calvé-Perthes disease: cross-sectional and longitudinal study.

Thyroid function was studied in 59 consecutive children with Legg-Calvé-Perthes disease (LCPD) and 239 controls. The subjects of both groups were generally euthyroid. In the Perthes group, however, plasma concentrations of free thyroxin (FT4) were increased by 16% (p < 10(-8)) and those of free triiodothyronine (FT3) were increased by 10% (p < 0.001) as compared with controls. There was a tendency toward higher FT4 levels in children with necrosis of more than one half of the femoral head (p < 0.015), as compared with those with lesser involvement. The observed moderate hormonal changes were already evident at the time of diagnosis of LCPD and were not appreciably influenced by stage of disease or mode of treatment, as determined by longitudinal evaluation of 38 children. Our data may support the assumption of other investigators that systemic abnormalities exist in children with LCPD, but the relation between these findings and the femoral head necrosis is not known.

Adolescent↗