Biomedical subjects

H-G Simank

Publications and source records attributed to H-G Simank.

8 recordsLinked to original sources

PubMed2006

[Improving the diagnosis of septic arthritis by use of a pediatric blood culture system].

BACKGROUND: Prognosis and outcome of bacterial joint infections are dependent on the fast and reliable identification of pathogens in the synovial fluid. Previous studies have suggested the possible advantage of using a blood culture system in contrast to conventional culture methods. PATIENTS AND METHODS: A total of 101 synovial specimens from patients presenting with symptoms suggesting septic arthritis were taken by aspiration with a sterile syringe. We compared the diagnostic results of automated analysis in a blood culture system against conventional culture on solid agar plates. RESULTS: Some 67 specimens (66.3%) were found to be negative in both preparations, while samples from 21 patients (20.8%) yielded the same microorganisms. In 13 cases (12.9%), the isolation of a pathogen was possible only with the blood culture method, whereas the conventional method never yielded a positive result when the blood culture was negative. Thus, the diagnostic yield was significantly improved by use of the blood culture system (P <0.001). CONCLUSION: The use of a commonly available blood culture system offers a fast, reliable and cost-effective approach for the diagnosis of septic arthritis and should therefore be considered as an useful alternative to conventional culture methods.

Adolescent↗

PubMed2006

Transplantation of mesenchymal stromal cells on mineralized collagen leads to ectopic matrix synthesis in vivo independently from prior in vitro differentiation.

BACKGROUND: Tissue engineering using mesenchymal stromal cells (MSC) represents a promising approach for bone regeneration. Nevertheless, the optimal constructs have yet to be determined. It still remains unclear if there is a benefit of in vitro differentiation of MSC prior to transplantation or if undifferentiated MSC hold the optimal potential concerning new tissue formation. METHODS: After isolation and in vitro expansion, MSC were seeded on mineralized collagen sponges and transplanted in a heterotopic SCID mice model (n=12). While group A contained undifferentiated MSC, in group B cells were cultivated for 14 days in vitro under osteogenic conditions prior to implantation. Results were compared with non-loaded scaffolds (group C). Animals were killed for investigation at 4 and at 8 weeks. RESULTS: In situ hybridization demonstrated integration of MSC for up to 8 weeks in groups A and B. Histology revealed significantly more extracellular matrix synthesis in MSC-seeded scaffolds containing calcium phosphate and collagen type I at 4 and 8 weeks after transplantation compared with unloaded controls. At a biochemical level, higher levels of specific alkaline phosphatase expression were detected in MSC-loaded scaffolds (P<0.05). Scaffolds containing undifferentiated and differentiated MSC did not appear to differ in terms of matrix synthesis and protein expression, while the number of avital cells was significant higher in those probes loaded with differentiated MSC (P<0.01). DISCUSSION: The integration of transplanted cells and MSC-associated matrix synthesis encourages the use of MSC-loaded mineralized collagen for tissue engineering of bone. Furthermore, our data suggest that in vitro differentiation of MSC does not have a positive influence in terms of improved matrix synthesis.

Adult↗

PubMed2005

Incidence of rotator cuff tears in shoulder dislocations and results of therapy in older patients.

INTRODUCTION: In older patients we documented the incidence of additional injuries in shoulder dislocations in a non-randomised, prospective study and compared the results of conservative and of operative therapy of rotator cuff tears. MATERIAL AND METHODS: Between 1993 and 1999 a total of 87 patients were prospectively enrolled. In the case of documented tears of the rotator cuff in combination with symptoms persisting after conservative therapy patients were free to decide between surgical and conservative treatment. Patients were monitored for function, subjective stability, and satisfaction over a minimum follow-up period of 1 year. RESULTS: In 54% of the patients enrolled a cuff tear was documented; the frequency increased with advancing age to 100% in patients over the age of 70. Surgical treatment of the cuff tears resulted in better function and satisfaction. There were three recurrences in the conservative treatment group, while no recurrences were documented in surgically treated patients. The significant benefit of cuff repair was confirmed by regression analysis. CONCLUSION: In this selected patient group, we believe surgical repair of the symptomatic rotator cuff tear should be discussed with the patient.

Adult↗

PubMed2004

[Growth and differentiation factor 5 (GDF-5) composite improves the healing of necrosis of the femoral head in a sheep model. Analysis of an animal model].

MATERIALS AND METHODS: After creation of necrosis in 23 sheep, the composites were implanted in half of the animals. The animals were sacrificed 6 and 12 weeks after implantation and the femora were harvested. The specimens were investigated by microradiography, computed tomography, and histologically. RESULTS: The GDF-5 composites were effective in the necrosis model. Osseous regeneration of the necrosis and the drill track were accelerated and enhanced by the composites. In treated animals the necrosis was nearly healed and the drill track was filled with bone after 12 weeks. In the control group the track was partially filled with fibrous tissue and necrotic lesions were still present. Specific side effects of the growth factor or the matrix were not documented. This was documented by histological scoring and CT investigation. DISCUSSION: The application of an absorbable GDF-5 composite in combination with a core decompression procedure may enhance the healing of devitalized bone defects and is a promising approach for further studies.

Animals↗

PubMed2004

[Joint empyema].

Joint infections represent a surgical emergency. For diagnosis, clinical, sonographic, and radiographic examinations are required. Furthermore, puncture of the joint with analysis of joint tap is mandatory. Therapy consists in administration of antibiotics, arthroscopic or open debridement with joint lavage, postoperative drainage and early active and passive mobilization of the joint without weight bearing. Early surgical revision is recommended in cases of insufficient recovery.

Adolescent↗

PubMed2003

[Telecommunication and telepathology in orthopedic oncology. Possibilities in diagnosis and therapy of primary malignant bone tumors].

The rareness of primary malignant bone tumors and the difficulty of differential diagnosis make this field a part of oncology in which the consulting physician must rely on consistent histopathological monitoring of highest quality throughout the diagnostic and therapeutic process. In a pilot project of the Department of Bone Pathology of the University of Hamburg and the Orthopedic Department of the University of Heidelberg, 190 cases of suspected primary bone tumor were the subject of interdisciplinary discussion between July 2001 and March 2003 using a telepathology system established for this purpose. Diligent differential diagnoses were made prior to the biopsy; optimal location and further strategy for the biopsy were discussed and determined according to the guidelines of the international bone tumor centers. This also included the decision if intraoperative pathological examination of frozen sections should be performed. In 51 cases such examinations were performed. Those results immediately influenced the surgical procedure. Telepathology performed as described in this article led to a close interdisciplinary cooperation over a large distance and helped significantly to optimize therapy of patients with malignant bone tumors.

Biopsy↗

PubMed2002

A new animal model of femoral head necrosis induced by intraosseous injection of ethanol.

There is no reliable animal model of the early stages of osteonecrosis of the femoral head (ONFH) for the evaluation of new therapeutic approaches. In this study, we propose a new animal model of femoral head osteonecrosis. Pure ethanol was injected into the centre of the femoral head in adult Merino sheep under fluoroscopic control. After 3, 6 and 12 weeks the animals were killed and the femoral heads were harvested. Microradiographic and histological changes were analysed and recorded. Partial necrosis was documented over a period of 12 weeks in all animals. The appearance of necrosis in combination with intact macrotexture, macrocirculation and joint cartilage is similar to the features described in early ONFH in humans. Due to its efficacy and its similarity to the early stages of ONFH in humans, this model may be suitable to evaluate new therapeutic techniques in the treatment of ONFH.

Animals↗

PubMedDate not supplied

[Mesenchymal stem cells for tissue engineering of bone: 3D-cultivation and osteogenic differentiation on mineralized collagen].

AIM: Due to their plasticity and high proliferation capacity in vitro, human mesenchymal stem cells (MSC) are promising candidates for substitution of mesenchymal tissues, such as bone. According to the tissue engineering concept, combinations of cells and three dimensional scaffolds are used to replace damaged tissue. Although various attempts have been made, the optimal combination of cells and artificial scaffold has not been found so far. METHODS: In this work, human MSC were isolated from bone marrow aspirates according to standard protocols and cultivated on mineralized collagen. Osteogenic differentiation was induced by medium containing dexamethasone, ascorbic acid and beta-glycerophosphate. Cell proliferation on the scaffold (WST-1 vitality assay, total protein measurement) and osteogenic differentiation (quantitative Real-Time-RT-PCR) were monitored for 24 days. RESULTS: Viable cells were found within the matrix throughout the cultivation period using histological and histochemical methods. Effective osteogenic differentiation could be demonstrated by the increase of expression of osteogenic marker genes (such as alkaline phosphatase) on a molecular level. CONCLUSION: Our results make the cell/matrix construct investigated in this work a promising candidate for tissue engineering of bone using mesenchymal stem cells. This has to be tested further by in vivo analysis.

Alkaline Phosphatase↗