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Biomedical subjects

M Maier

Publications and source records attributed to M Maier.

At least 19 recordsLinked to original sources
PubMed2003

Investigations on the inflammatory and genotoxic lung effects of two types of titanium dioxide: untreated and surface treated.

TiO(2) is considered to be toxicologically inert, at least under nonoverload conditions. To study if there are differences in lung effects of surface treated or untreated TiO(2) we investigated the inflammatory and genotoxic lung effects of two types of commercially available TiO(2) at low doses relevant to the working environment. Rats were exposed by instillation to a single dose of 0.15, 0.3, 0.6, and 1.2 mg of TiO(2) P25 (untreated, hydrophilic surface) or TiO(2) T805 (silanized, hydrophobic surface) particles, suspended in 0.2 ml of physiological saline supplemented with 0.25% lecithin. As control, animals were instilled with the vehicle medium only or with a single dose of 0.6 mg quartz DQ12. At days 3, 21, and 90 after instillation bronchoalveolar lavage was performed and inflammatory signs such as cells, protein, tumor necrosis factor-alpha, fibronectin, and surfactant phospholipids were determined. Additionally, 8 microm frozen sections of the left lobe of the lung were cut and stored at -80 degrees C. The sections were used for immunohistochemical detection of 8-oxoguanine (8-oxoGua) by a polyclonal antibody in the DNA of individual lung cells. In the quartz-exposed animals a strong progression in the lung inflammatory response was observed. Ninety days after exposure a significant increase in the amount of 8-oxoGua in DNA of lung cells was detected. In contrast, animals exposed to TiO(2) P25 or TiO(2) T805 showed no signs of inflammation. The amount of 8-oxoGua as a marker of DNA damage was at the level of control. The results indicate that both types of TiO(2) are inert at applicated doses.

Air Pollutants, Occupational↗
PubMed2003

Resurfacing knee arthroplasty in patients with allergic sensitivity to metals.

BACKGROUND: The problem of metal sensitivity (Ni, Cr, and Co) in arthroplasty is still unsolved. To prevent the risk of allergy in cases with proved metal allergy in an epicutaneous test, a Natural Knee total knee arthroplasty, made totally from titanium (Ti-6Al-4V) and polyethylene, can be implanted. The results of this device have to be compared to the results of normal knee arthroplasty designed with a femoral component out of CrCoNi alloy. The mechanical resistance of this alloy is much higher than that of titanium, and therefore it is the standard for the femoral components of most knee-resurfacing devices. METHODS: Thirty-five patients with a titanium Natural Knee were examined retrospectively after a mean follow-up of 2 years and 5 months (range 6 months to 5 years and 4 months). In comparison, 36 patients with a Genesis-I knee with a CrCoNi alloy femoral component were studied after a mean follow-up of 2 years and 4 months (range 8 months to 6 years and 2 months). RESULTS: In spite of the lower mechanical resistance of titanium, the Natural Knee showed better results (knee score 84.1 points, function score 77.7 points, HSS score 80.1 points, 82.9% excellent and good results) than the Genesis-I knee (knee score 80.6 points, function score 76.4 points, HSS score 76.4 points, 68.5% excellent and good results), although these differences had no statistical significance. CONCLUSIONS: The titanium Natural Knee prosthesis has proven to be a reliable knee joint replacement in the medium term.

Adult↗
PubMed2003

Irregular rotation and shift of computer-assisted femoral stem implantation in THA--an experimental study.

INTRODUCTION: The two available computer-assisted surgery robotic systems consist of a preoperative planning computer workstation and an industrial robot with a high speed milling device. During the computed tomography (CT) scan of the hip and the ipsilateral knee for planning the hip arthroplasty, the patient's movements are registered by a bar that is fixed at the patient's leg along its axis. Despite the companies' claim that a high accuracy of implant position can be achieved by this method, misplacements of implants are reported in the literature. MATERIALS AND METHODS: In an experimental study, a cadaver femoral bone was rotated during the CT scan strictly around this bar to simulate a rotational movement of the patient. Using the CT data, the planning of the hip stem and the following preparation of the femur by the robot was possible without detection of the patient's movements by the system. According to the system manual, the computer should stop the planning or give a warning in case of patient movement during the CT scan. RESULTS: The postoperative CT scan of the cadaver femoral bone revealed a rotary deviation and a shift of the stem compared with the original planning, caused by the rotation during the CT scan. CONCLUSION: We propose using a second bar during the CT scan to detect these movements and thus avoiding misplacement of the implant.

Arthroplasty, Replacement, Hip↗
PubMed2003

[Results of femoral shaft fractures in childhood in relation to different treatment modalities].

The clinical and radiological results of femoral shaft fractures in childhood were evaluated and compared in relation to different treatment modalities. One hundred and one children (mean age 5+/-0,4 years) were treated between 1990 to 1999. 38% of the patients were treated conservatively (mean age 2,2+/-0,5 years), 32% of the patients (mean age 6+/-0,5 years) were treated by external fixation, 17% were treated with elastic stable intramedullary nailing (ESIN, mean age 5,6+/-0,8 years) and 12% underwent other internal fixation procedures. The duration of hospital stay was significantly longer in the conservative treatment group (18+/-1,6 days) than in the external fixator (12+/-1,2 days) as well as in the ESIN group (8+/-0,9 days). Radiological controls revealed a significantly better reduction of the fracture by operative procedures (external fixator,ESIN) as compared to conservative management. Complications, i.e. secondary dislocation or infection, occurred in 25% of patients in the external fixator group,6% of the ESIN patients, and in 10% of the conservatively treated patients. Late complications,i.e.weight bearing dependent pain or hypertrophic scarring,were developed in both the conservative treatment group (4%) and in the external fixator group (19%); however,no late complications were seen in the ESIN group. While each method examined is known to be suitable for treatment of femoral shaft fractures in childhood,each has defined indications. Also there is a limited possibility of fracture reduction in conservative treatment this method is indicated in younger children (<4 years) where spontaneous bone remodelling is likely. For older children the ESIN method showed a low rate of complications and demonstrates the best long term results. When ESIN is not possible because of local soft tissue damage,additional injuries,or in complex fractures, the external fixator proved to be an alternative treatment for femoral shaft fractures.

Adolescent↗
PubMed2003

[The roentgenmorphologic aspects of symptomatic calcifications in patients with calcifying tendinitis of the shoulder: determination of intra- and interobserver variabilities of Gärtner's classification].

AIM OF THE STUDY: The roentgenologic morphology of symptomatic calcified deposits of the rotator cuff can be classified according Gärtner. This classification influences therapeutic procedures and prognosis of clinical outcome in these patients. In the present study intraoberserver-reproducibility and interobserver-reliability of Gärtner's classification were tested. METHODS: Plane radiographs of 100 patients with calcifications of the supraspinatus tendon were classified according the criteria of Gärtner by 6 independent observers twice within 4 months. Intraoberserver-reproducibility and interobserver-reliability were calculated by means of Cohen's kappa-index. RESULTS: kappa-values of intraoberserver-reproducibility had a mean of 0.4208 (SD 0.1299), kappa-values of interobserver-reliability were 0.490 for the first and 0.474 for the second classification. CONCLUSIONS: Determination of intraoberserver-reproducibility gave insufficient to satisfactory results, interobserver-reliability was sufficient. The clinical use of Gärtner's classification to plan therapeutic procedures or to determine clinical prognosis in patients with calcifying tendinitis can be recommended only with limitations.

Adult↗
PubMed2003

[Chronic recurrent multifocal osteomyelitis].

Chronic recurrent multifocal osteomyelitis (CRMO) is a rare, inflammatory, skeletal disease of unknown origin, which mainly affects children and adolescents in terms of cleido-spondylo-metaphysal skeletal inflammation. Only 10% of the patients are older than 20 years. To date, only about 200 cases have been reported in the literature. In the course of the disease, the initial radiological signs are osteolysis followed by sclerosis and hyperostosis in the end stage. The histological investigations reveal chronic inflammatory infiltrates with lymphocytes and hyperostosis. Although the prognosis of CRMO, to our current understanding, is self limiting, serious complications have been reported such as pathological fractures and compression fractures of the spine. A recently recommended therapy scheme is based on the administration of azithromycin combined with calcitonin. We present the case of a 25 year old female patient who has suffered from CRMO for 1.5 years with the cervical spine and the manubrium sterni being affected. The current state of diagnosis, therapy, and prognostic outlook of this rare disease are discussed.

Adult↗
PubMed2003

[Functional morphology of the elbow joint].

The distribution of the thickness of cartilage as well as of the subchondral mineralization reflects the various stresses on the joint compartments. Both long bones of the lower arm participate in load bearing. The humeroradial and humeroulnar parts of the joint are incongruent. The capitulum humeri is slightly smaller than the corresponding fovea, whereas the radius of the trochlea is bigger than that of the incisura trochlearis. Therefore, the medial compartment can be seen as a dynamic pressure-transmitting system. The collateral ligaments limit the degree of flexion and extension together with the olecranon and coronoid process. In the extreme flexed position the insertion regions of the ligaments at the humeral crests are twisted. This may explain why the corresponding entheses consist of fibrocartilage. Some molecular components of these regions can become targets of autoimmune reactions. The rotational movements are restricted by soft tissues and muscles.

Cartilage, Articular↗
PubMed2003

Solitary enchondromas: is radiographic follow-up sufficient in patients with asymptomatic lesions?

Enchondromas are benign cartilaginous tumours and rarely transform into chondrosarcomas. Curettage is usually performed, and a low rate of complications is assumed. We analysed retrospectively data from 73 patients with enchondromas treated by curettage with respect to symptoms, therapy, complications and recurrences. All patients were treated by curettage of the tumour, in most cases followed by cancellous bone grafting. Twenty-three percent of the patients presented a complication. There were two recurrences but no malignant transformations in the follow-up period. During the same time period 29 patients with chondrosarcomas were treated, including two secondary chondrosarcomas. One had a recurrence of a benign enchondroma of the metacarpal and developed a pulmonary metastasis from a chondrosarcoma. The other was a patient with Ollier's disease who had a secondary chondrosarcoma of the radius. Malignant transformation of a solitary enchondroma to a chondrosarcoma is rare. On the other hand the complication rate of enchondroma curettage is considerable. Regular radiological follow-up of asymptomatic enchondromas may therefore be the better option.

Adolescent↗
PubMed2002

Investigating regional white matter in schizophrenia using diffusion tensor imaging.

Diffusion tensor imaging (DTI) was used to investigate regional white matter in vivo in patients with schizophrenia. DTI is capable of providing information about the organization of white matter tracts and has only recently been used to study schizophrenia. In this study, a voxel based analysis of DTI maps in 14 patients and 19 controls did not reveal any areas of significant differences in DTI measures in white matter. The findings suggest that the structural integrity of white matter in these patients was not disrupted. These results are discussed in relation to previous studies reporting positive findings. It is concluded that further studies using DTI in larger samples, improved and standardised methods of data acquisition and analysis are needed.

Adult↗
PubMed2002

Side-effects of extracorporeal shock wave therapy (ESWT) in the treatment of tennis elbow.

Apart from a few observational reports, there are no studies on the side-effects of extracorporeal shock wave therapy (ESWT) in the treatment of insertion tendopathies. Within the framework of a randomised, placebo-controlled, single-blind, multicentre study to test the effectiveness of ESWT in the case of lateral epicondylitis (LE), side-effects were systematically recorded. A total of 272 patients from 15 centres was allocated at random to active ESWT (3 x 2000 pulses, energy flux density ED(+) 0.04 to 0.22 mJ/mm(2) under local anaesthesia) or placebo ESWT. In all, 399 ESWT and 402 placebo treatments were analysed. More side-effects were documented in the ESWT group (OR = 4.3, CI = [2.9; 6.3]) than in the placebo group. Most frequently, transitory reddening of the skin (21.1%), pain (4.8%) and small haematomas (3.0%) were found. Migraine was registered in four and syncopes in three instances after ESWT. ESWT for LE with an energy flux density of ED(+) 0.04 to 0.22 mJ/mm(2) is a treatment method which has very few side-effects. The possibility of migraine being triggered by ESWT and the risk of a syncope should be taken into account in the future. No physical shock wave parameters could be definitely identified as the cause of the side-effects observed.

Adult↗
PubMed2002

[The sublabral foramen. Congenital or an acquired variance?].

The sublabral foramen is considered to be a clinically asymptomatic, isolated variant of the anterior-superior capsulo-labral-complex. It may be observed during shoulder arthroscopy and may implicate problems in differential diagnosis of traumatic lesions. In an anatomic study on 89 macroscopically healthy shoulder specimens the age distribution and the incidence in relation to the varying shape of the glenoid as feasible factors of influence for a sublabral foramen (SF) were analyzed in order to elucidate the unknown pathogenesis of SF. In addition histologic sections of three SF samples were obtained. Mean age of the specimens with a sublabral foramen [n=20; 69 (37-84) years] was significantly higher (p=0.04) compared to samples without a sublabral foramen [n=69; 59 (18-94) years]. An increased incidence of a sublabral foramen in relation to a distinct shape of the glenoid could not be established although a prevalence of a glenoid with anterior notch was observed. The results indicate an age-related development of the sublabral foramen,thus in younger patients with an anterior-superior capsulolabral displacement local signs of trauma and involvement of the biceps anchor should be controlled before definitive diagnosis.

Adolescent↗
PubMed2002

[Physical-technical principles of extracorporeal shockwave therapy (ESWT)].

Extracorporeal shock waves in orthopaedics are currently applied in the treatment of chronic enthesiopathies such as lateral epicondylitis, plantar heel spur, as well as in calcifying tendinitis of the shoulder or in bony nonunions. Detailed knowledge of physical parameters and properties of shock waves appear to be necessary to determine clinically relevant dose-effect relations and to make shock wave devices, clinical results, and basic science in shock wave therapy more comparable. This study gives an overview of physical parameters and properties in shock wave therapy. Measurement technologies, types of shock wave devices, and mechanisms of shock waves are also described.

Computer Simulation↗
PubMed2002

[Basic research of applying extracorporeal shockwaves on the musculoskeletal system. An assessment of current status].

Detailed knowledge concerning the action of extracorporeal shock waves on the locomotor system as well as concerning possible side effects of extracorporeal shock wave therapy (ESWT) are crucial to optimize the clinical use of ESWT for the treatment of illnesses such as calcific tendinitis of the shoulder, tennis elbow, plantar fasciitis, aseptic pseudarthrosis, and aseptic hip necrosis. This study presents the current knowledge gained from animal experiments, which have yielded important findings, in particular concerning possible side effects of ESWT. Very recent studies have also provided valuable insights into the molecular actions of extracorporeal shock waves on the locomotor system. Further intensified experimental animal research will greatly improve the scientific basis for the clinical use of ESWT in the near future.

Animals↗
PubMed2002

The relation between primary osteoarthritis of the trapeziometacarpal joint and supernumerary slips of the abductor pollicis longus tendon.

We have studied whether accessory abductor pollicis longus slips inserting into the thenar eminence or trapezium influence the incidence and severity of trapeziometacarpal joint osteoarthritis. The right first extensor compartment of 73 cadavers was dissected and trapeziometacarpal degeneration was graded macroscopically. The main abductor pollicis longus tendon which inserted at the metacarpal base was accompanied by supernumerary APL slips in 96% of cases. Thenar or trapezial slips occurred frequently but coexisted in only one case. The incidence of trapeziometacarpal arthritis was not influenced by the number of accessory slips or whether they inserted onto the thenar eminence or the trapezium.

Aged↗
PubMed2002

Differential function of nitric oxide in murine antigen-induced arthritis.

BACKGROUND: The aim of our study was to investigate the role of inducible nitric oxide synthase (iNOS)-derived nitric oxide (NO) production in different stages of murine antigen-induced arthritis (AiA). METHODS: Clinical, histological and microcirculatory parameters (measured by intravital fluorescence microscopy) were assessed in the knee joint during acute and chronic AiA after inhibition of iNOS with L-N(6)-(1-iminoethyl)lysine (L-NIL). Plasma concentrations of and were evaluated by the Griess reaction and the expression of iNOS, P- and E-selectin, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) by immunohistochemistry. RESULTS: In both stages of the disease, plasma concentrations of and were increased and iNOS was expressed. In the acute phase, swelling, leucocyte adhesion, leucocyte infiltration and expression of adhesion molecules were increased in arthritic animals treated with L-NIL in comparison with untreated arthritic animals. In the chronic phase, no change in the disease parameters could be detected after L-NIL treatment. CONCLUSION: Increased NO production induced by iNOS during the acute phase of AiA can be regarded as a protective response in the prevention of further leucocytic infiltration and joint destruction, whereas it seems to play a subordinate role in chronic AiA.

Acute Disease↗
PubMed2002

An immunohistochemical study of the rabbit suprapatella, a sesamoid fibrocartilage in the quadriceps tendon containing aggrecan.

The rabbit suprapatella is a sesamoid fibrocartilage in the deep surface of the tendon of vastus intermedius and an integral part of the knee joint. We report the presence of a variety of proteoglycans (aggrecan and versican), glycosaminoglycans (chondroitin 4 and 6 sulfate, dermatan sulfate, keratan sulfate) and glycoproteins (tenascin) in its extracellular matrix and the intermediate filament vimentin in the fibrocartilage cells. The most significant finding is the presence of aggrecan in the extracellular matrix, along with its associated link protein and several of its integral glycosaminoglycans. Aggrecan probably enables the suprapatella to withstand compression. Although it can be assumed that aggrecan metabolites detected in synovial fluid from some human joints are predominantly associated with articular hyaline cartilage, the presence of aggrecan in the rabbit suprapatella means that this cannot be assumed for all animal knee joints. We conclude that it is important for orthopedic researchers who use animal models for arthritis research to check for the presence of a suprapatella when joint fluid analyses are interpreted.

Aggrecans↗
PubMed2002

Influence of extracorporeal shock-wave application on normal bone in an animal model in vivo. Scintigraphy, MRI and histopathology.

There is little information about the effects of extracorporeal shock-wave application (ESWA) on normal bone physiology. We have therefore investigated the effects of ESWA on intact distal rabbit femora in vivo. The animals received 1500 shock-wave pulses each of different energy flux densities (EFD) on either the left or right femur or remained untreated. The effects were studied by bone scintigraphy, MRI and histopathological examination. Ten days after ESWA (0.5 mJ/mm2 and 0.9 mJ/mm2 EFD), local blood flow and bone metabolism were decreased, but were increased 28 days after ESWA (0.9 mJ/mm2). One day after ESWA with 0.9 mJ/mm2 EFD but not with 0.5 mJ/mm2, there were signs of soft-tissue oedema, epiperiosteal fluid and bone-marrow oedema on MRI. In addition, deposits of haemosiderin were found epiperiosteally and within the marrow cavity ten days after ESWA. We conclude that ESWA with both 0.5 mJ/mm2 and 0.9 mJ/mm2 EFD affected the normal bone physiology in the distal rabbit femur. Considerable damaging side-effects were observed with 0.9 mJ/mm2 EFD on periosteal soft tissue and tissue within the bone-marrow cavity.

Animals↗