Biomedical subjects

O Rolf

Publications and source records attributed to O Rolf.

5 recordsLinked to original sources

PubMed2002

Detection of differentially expressed genes in particle disease using array-filter analysis.

UNLABELLED: The precise cellular mechanism of osteolysis in particle disease is still unknown. The aim of the study was to screen for new gene products in macrophages during particle contact. METHOD: In an established macrophage model THP1-cells (human monocytic cells) were differentiated under the influence of vitamin D3 and GM-CSF into macrophage-like cells (MLC). MLCs were incubated each with different concentrations of polyethylene particles, Lipopolysaccharids (LPS) and controls. Isolated RNA was transcribed into complementary radioactive 32P labeled cDNA. This probe was hybridised on an human cDNA expression array and analysed by autoradiography. To obtain a more reliable method quantifying mRNA, the reverse transcriptase polymerase chain reaction (RT-PCR) was used. RESULTS: The arrays showed an upregulation of the following genes by particles: TNF-Rezeptor 2, IL-1 Receptor Antagonist, Bone Morphogenic Protein 4 and HM 145. This was proven three times using RT-PCR and statistically significant in comparison to the controls. LPS induced the same upregulation except for HM145 whereas particles caused downregulation of this mRNA expression. CONCLUSION: Our results prove that the model of differentiated THP-1 cells treated with PE particles is a suitable system to analyse differential gene expression patterns, since the induction of the major positive control genes TNF alpha and IL1 beta were detected by this approach. BMP 4 is known as signal protein which mediates ectopic bone formation and can also be interpreted as a contra regulatory gene. HM 145 belongs to the leukocyte chemotactic peptide receptor family. HM 145 seems to be one of the first genes that is enhanced along the septical pathway but less expressed by contact with particles. Analysis of HM 145 expression might help to diagnose septic versus aseptic loosening of prosthesis.

Bone Morphogenetic Protein 4↗

PubMed1999

[TNF-alpha secretion by human macrophage-like cells in response to wear particles and its modification by drugs].

UNLABELLED: Tumour necrosis factor (TNF) is considered to be the initiator protein of particle disease leading to aseptic loosening of endoprostheses. The aim of the present study was to investigate the TNF response of the macrophage-like cells (MLC) to the periprosthetic particles typically found during revision surgery. For this purpose, particles of polyethylene (PE), pure titanium (Ti), chromium (Cr), cobalt (Co), alumina ceramic (Al2O3) and zirconium dioxide (ZrO2) were used. Additionally, the therapeutic effect of non-steroidal and steroidal drugs, biphosphonates and pentoxyfylline on PE particles was investigated with the aim of differentiating drugs with, from those without, a positive effect on aseptic loosening. METHOD: In an established macrophage model (Rader et al. 1999), THP1 cells (human monocytic cell line) were differentiated over a period of five days in the presence of vitamin D3 and GM-CSF in macrophage-like cells (MLC). To obtain a TNF profile of the different materials, 10(6) MLC were incubated with each of a range of different particle concentrations. For drug testing purposes 80 x 10(8) PE particles, which evoked a maximum TNF response, were applied together with increasing drug concentrations in the same manner. The supernatant was then investigated for TNF secretion using ELISA. RESULTS: It was found that the greatest TNF response was provoked by Co and PE particles, and was 25 and 23 times as high, respectively, in comparison with control. The smallest TNF secretion was seen with Al2O3 (4 x control) and ZrO2 (5 x control). At the recommended dose, non-steroidal anti-inflammatory drugs (NSAIDs) produced no decrease in TNF secretion. The biphosphonates, etidronate and ibendronate significantly reduced the TNF response of the PE-stimulated macrophages (by 1/7 and 1/5, respectively). Therapeutic doses of pentoxyfylline also led to a decrease of 1/5 in maximum TNF release. CONCLUSION: Ceramic articulating surfaces are superior to metal/metal or PE/PE matings in terms of the biological effects of their wear particles. At therapeutic doses, NSAIDs have no beneficial effect on the process of aseptic loosening. Certain biphosphonates and pentoxyfylline have a positive effect on aseptic loosening.

Biocompatible Materials↗

PubMed1997

Nucleotide and corrected amino acid sequence of the functional recombinant rat anaphylatoxin C5a.

For bacterial expression of rat anaphylatoxin C5a, the cDNA was amplified by reverse transcriptase-polymerase chain reaction (RT-PCR) using rat liver RNA and degenerate primers designed according to the published amino acid sequence [1]. Surprisingly, the amino acid sequence deduced from cDNA differed at positions 55 (N for K), 63 (K for H), 67 (E for N), 68 (S for E) and 69 (H for S) from the published sequence. The overall amino acid composition, however, was unchanged because these 5 amino acids were located at different positions compared to the published sequence. As a consequence, the proposed N-glycosylation site was absent, suggesting O-glycosylation of the mature molecule. Recombinant rat C5a with a 6 histidine tag at the N-terminus was expressed in bacteria, purified and renatured. The peptide was as potent as recombinant human C5a in eliciting lysosomal enzyme release from human granulocytes.

Amino Acid Sequence↗

PubMedDate not supplied

[Intra-acetabular localisation of an osteochondroma causing subluxation of the hip joint].

INTRODUCTION: Intra-acetabular localisation of an osteochondroma causing subluxation of the hip joint is a rare entity in children suffering from multiple hereditary exostoses. In literature only 6 operatively treated cases have been reported. CASE: We add the case of an 8-year-old boy with an intraarticular exostosis of the left acetabulum causing subluxation of the hip. Using an anterolateral approach to the hip joint this exostosis was removed surgically together with some extraarticular exostoses of the proximal femur. The hip could be re-centered in combination with an additional varus derotation osteotomy of the proximal femur. Intraoperatively the femoral head was only subluxated to minimise the risk of avascular necrosis. After a follow-up of two years the patient has complete remission of symptoms and there is no evidence of avascular necrosis radiologically with good remodelling of the left hip. CONCLUSION: The operative treatment of an intraarticular exostosis of the hip joint is a difficult and risky surgical procedure. The reported open surgical procedure allowed resection of the intraarticular exostosis in combination with therapy of additional pathologies of the proximal femur.

Acetabulum↗

PubMedDate not supplied

[Rotator cuff tear--an occupational disease? An epidemiological analysis].

BACKGROUND: In literature there are only few data which describe the influence of occupation on the development of rotator cuff disease. METHODS: In a retrospective study, 760 open rotator cuff repairs were analysed and related to the profession and occupational load. Exclusion criteria were traumatic tears and sports injuries. All male persons were statistically analysed and the data compared with occupational patterns of the region, obtained from the Federal Statistical State Office. RESULTS: Rotator cuff repairs were performed in 472 males who had no evidence for a traumatic origin. After statistical analysis (p < 0.001) we found significantly more patients working in agriculture and forestry (6.38% versus 1.07% in Bavaria) and in the building industry (35.11% versus 13.40% in Bavaria). CONCLUSIONS: Our data suggest that working exposure increases the risk or leads to the clinical manifestation of rotator cuff tears. Although a detailed analysis of individual physical exposure is not available yet, the statistical results indicate that rotator cuff tears must be taken into consideration as a result of ergonomic exposure.

Adult↗