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Biomedical subjects

Wolf Petersen

Publications and source records attributed to Wolf Petersen.

60 records · Page 4Linked to original sources
PubMed2002

Arthroscopical removal of a projectile from the intra-articular cavity of the knee joint.

We report the case of a 29-year-old patient with an uncommon handgun accident. A gun was resting in his pocket when an accidental shot was fired. The projectile penetrated the skin of the thigh, travelled through the quadriceps muscle and entered the articular cavity at the upper pole of the suprapatellar recess. It passed the femoropatellar joint space and stopped within the infra-articular fad pad. The bullet was localized by conventional X-rays and removed by arthroscopy. The patient developed no infection, and in a clinical follow-up examination 6 months postoperatively, we observed no pathological findings.

Adult↗
PubMed2002

Antimicrobial peptides are expressed and produced in healthy and inflamed human synovial membranes.

The objective of this study was to determine the expression and production of antimicrobial peptides by healthy and inflamed human synovial membranes. Deposition of the antimicrobial peptides lysozyme, lactoferrin, secretory phospholipase A(2) (sPA(2)), matrilysin (MMP7), human neutrophil alpha-defensins 1-3 (HNP 1-3), human beta-defensin 1 (HBD-1), and human beta-defensin 2 (HBD-2) was determined by immunohistochemistry. Expression of mRNA for the antimicrobial peptides bactericidal permeability-increasing protein (BPI), heparin binding protein (CAP37), human cationic antimicrobial protein (LL37), human alpha-defensin 5 (HD5), human alpha-defensin 6 (HD6), HBD-1, HBD-2, and human beta-defensin 3 (HBD-3) was analysed by reverse transcription polymerase chain reaction (RT-PCR). RT-PCR revealed CAP37 and HBD-1 mRNA in samples of healthy synovial membrane. Additionally, HBD-3 and/or LL37 mRNA was detected in synovial membrane samples from patients with pyogenic arthritis (PA), osteoarthritis (OA) or rheumatoid arthritis (RA). BPI, HD5, HD6, and HBD-2 mRNAs were absent from all samples investigated. Immunohistochemistry identified lysozyme, lactoferrin, sPA(2), and MMP7 in type A synoviocytes of all samples. HBD-1 was only present in type B synoviocytes of some of the samples. Immunoreactive HBD-2 peptide was only visible in some inflamed samples. HNP1-3 was detected in both healthy and inflamed synovial membranes. The data suggest that human synovial membranes produce a broad spectrum of antimicrobial peptides. Under inflammatory conditions, the expression pattern changes, with induction of HBD-3 in PA (LL37 in RA; HBD-3 and LL37 in OA) as well as down-regulation of HBD-1. HBD-3 holds therapeutic potential in PA as it has a broad spectrum of antimicrobial activity and accelerates epithelial healing. However, caution is appropriate since defensins also promote fibrin formation and cell proliferation - key elements in joint infection. Clarification of the role of antimicrobial peptides in OA and RA will require further investigation.

Anti-Bacterial Agents↗
PubMed2002

Expression of VEGF121 and VEGF165 in hypertrophic chondrocytes of the human growth plate and epiphyseal cartilage.

Vascular endothelial growth factor (VEGF) plays an important role during endochondral bone formation in hypertrophic cartilage remodelling. We examined VEGF and VEGF receptor expression in tibiae from fetuses, newborns and children immunohistochemically. Expression of mRNA for the different VEGF splice forms and for VEGF receptors KDR and FLT-1 was analysed by reverse transcription-polymerase chain reaction (RT-PCR). VEGF could be immunolocalized intracellularly in the hypertrophic chondrocytes of the growth plate and in the chondrocytes around cartilage canals of the epiphysis, respectively. The resting zone and the proliferative zone of the growth plate were VEGF-negative. In cartilage samples of all growth plates analysed, VEGF121 and VEGF165 were identified as the only VEGF splice forms expressed. RT-PCR for VEGF mRNA of normal hyaline cartilage was negative. At vessels growing into the hypertrophic cartilage FLT-1 (VEGFR-1) and KDR (VGEFR-2) could be visualized. Reverse transcription-polymerase chain reaction (RT-PCR) substantiated the results regarding FLT-1 and KDR expression. The results of our study suggest that the splice forms VEGF121 and VEGF165 and the receptors KDR and FLT-1 of the known angiogenetic peptide VEGF play a role in process of endochondral ossification.

Adolescent↗
PubMed2002

Arthroscopic all-inside meniscus repair using a new refixation device: a prospective study.

PURPOSE: To evaluate complications and clinical results after meniscus refixation using a new all-inside technique. TYPE OF STUDY: Prospective clinical study. METHODS: This study reports clinical results of 37 patients after refixation of an unstable bucket-handle meniscus tear using a new all-inside technique (Mitek Meniscal Repair System; Mitek, Ethicon, Norderstedt, Germany). Twenty tears were located in the peripheral third (red zone) and 17 in the middle third (red/white zone). The average operating time of meniscus refixation was 29.4 minutes. In 17 patients, a reconstruction of the anterior cruciate ligament (ACL) was performed 6 to 8 weeks after the refixation. All patients (aged 15 to 48 years) were re-examined after a minimum follow-up of 12 months. RESULTS: In the ACL group (n = 17) we examined the menisci arthroscopically at surgery. All menisci were still in the reduced position and they were stable to probing. In 12 cases, the anchors were not visible at arthroscopy; in 7 cases, the vertical bar was lying just beyond the femoral meniscus surface. In 1 case, we observed superficial damage of the femoral cartilage in the corresponding area. One patient developed superficial posteromedial knee pain after 4 weeks due migration of a staple into the subcutaneous fat tissue. There were 5 reruptures during the first postoperative year. Two patients reported an adequate trauma, but all had tears in the middle one third of the meniscus (red/white zone). At the 1-year follow-up, none of the remaining 32 patients had clinical symptoms indicating a rerupture such as blocking, medial joint pain, or positive meniscus signs. No patient had an effusion or local swelling. The average pretraumatic Lysholm score decreased from 95 to 91 points. The Tegner activity score decreased from 4.9 (pretrauma) to 3.6 (postoperatively). CONCLUSIONS: Short-term clinical results using an all-inside meniscus repair system seem to be promising. However, a longer follow-up is needed.

Adolescent↗
PubMedDate not supplied

Initial fixation strength of two bioabsorbable pins for the fixation of hamstring grafts compared to interference screw fixation: single cycle and cyclic loading.

BACKGROUND: During the early postoperative period, the fixation of a hamstring graft to the bone tunnel is the primary factor in limiting rehabilitation. HYPOTHESIS: The initial fixation strength of a double cross pin fixation technique is comparable with the biodegradable interference screw fixation technique. STUDY DESIGN: Experimental laboratory study. METHODS: The authors examined the initial fixation strength of two 3.3-mm bioabsorbable pins compared to interference screws for hamstring grafts in bovine knees. RESULTS: Analysis of yield load, maximum load, and stiffness in the single-cycle loading test showed no statistically significant differences for cross pin and interference fixation (P <.05). For cross pins and interference screws, the mean displacement under 1000 cycles to 250 N was 5.07 ( +/- 1.9) mm and 4.81 ( +/- 2.5) mm, stiffness 252 ( +/- 78) N/mm and 289 ( +/- 148) N/mm. Only grafts fixed with cross pins survived 1000 cycles to 450 N. CONCLUSION: The initial fixation strength of the double cross pin technique is comparable to that of interference screw fixation with a stiffness comparable to that of the native ACL. CLINICAL RELEVANCE: Hamstring graft fixation using two cross pins provides an alternative to bioabsorbable interference screw fixation.

Absorbable Implants↗