Biomedical subjects

G Lovász

Publications and source records attributed to G Lovász.

9 recordsLinked to original sources

PubMed2001

Variations in susceptibility to proteoglycan-induced arthritis and spondylitis among C3H substrains of mice: evidence of genetically acquired resistance to autoimmune disease.

OBJECTIVE: To identify and screen the level of arthritis susceptibility in C3H murine strains known to be resistant to proteoglycan (aggrecan)-induced arthritis, and to measure and correlate various immunologic and inflammatory parameters with susceptibility to either arthritis or spondylitis in various C3H substrains. METHODS: Mice of 10 C3H substrains (subcolonies) were immunized with cartilage proteoglycan (aggrecan) for induction of arthritis. Animals were assessed for clinical symptoms, and the peripheral joints and spine were studied by histologic methods. Proteoglycan-specific T cell responses (T cell proliferation and production of interleukin-2 [IL-2], interferon-y, and IL-4) and the B cell response to lipopolysaccharide (LPS) were measured in spleen cell cultures. Serum levels of heteroantibodies and autoantibodies as well as various cytokines (IL-6, IL-10, IL-12, and tumor necrosis factor alpha) and soluble CD44 were determined by enzyme-linked immunosorbent assay. RESULTS: Immunization with cartilage proteoglycan induced severe arthritis in the C3H/HeJCr substrain (95-100% incidence), whereas the original parent mice of the C3H/HeJ colony were resistant to proteoglycan (aggrecan)-induced arthritis. Furthermore, the progressive polyarthritis that is characteristic in susceptible C3H/HeJCr mice was accompanied by progressive inflammation around the spine. In subsequent experiments, 10 different C3H colonies with largely identical genetic backgrounds (all originating from the National Institutes of Health or Jackson Laboratory) exhibited extreme differences in susceptibility. Although none of the laboratory findings, including LPS hyporesponsiveness, immunologic parameters, and inflammatory markers, showed a correlation with susceptibility or resistance in the C3H/HeJCr and C3H/HeJ substrains, respectively, significant differences were found when all arthritic C3H mice were compared with all nonarthritic animals, regardless of their substrain origin. CONCLUSION: Because many of the C3H substrains lost arthritis susceptibility or acquired resistance, our results suggest that a preferred site for a mutation(s) in a gene(s) in a relatively upstream position of the inflammatory cascade is present. This is the first autoimmune model that exhibits extreme differences in arthritis susceptibility in the same murine strain, and is therefore a valuable tool for identification of arthritis-susceptible (or arthritis-suppressive) genes.

Animals↗

PubMed2001

Characteristics of degeneration in an unstable knee with a coronal surface step-off.

To investigate the effect of instability on the remodelling of a minor articular surface offset, we created a 0.5 mm coronal step-off of the medial femoral condyle in 12 New Zealand white rabbits and transected the anterior cruciate ligament (ACL). A control group of 12 rabbits had only ACL resection and the opposite knee was used as the non-operated control. The osteoarthritic changes at 6, 12 and 24 weeks after surgery were evaluated histologically. In addition, changes in the immunological detection of 3-B-3(-) and 7-D-4 chondroitin-6-sulphate epitopes were determined because of the previous association of such changes with repair of cartilage and early osteoarthritis. In the instability/step-off group there was rapidly progressing focal degeneration of cartilage on the high side of the defect, not seen in previous step-off studies in stable knees. The rest of the femoral condyles and the tibial plateaux of the instability/step-off group had moderate osteoarthritis similar to that of the instability group. 3-B-3(-) was detectable in the early and the intermediate stages of osteoarthritis but no staining was seen in the severely damaged cartilage zones. Immunoreactivity with 7-D-4 increased as degeneration progressed.

Animals↗

PubMed2000

A prospective comparative analysis of mobility in osteoarthritic knees.

We have sought to clarify whether the traditional Arabic lifestyle prevents restriction of movement in patients with degenerative arthritis of the knee. The range of movement of 68 osteoarthritic knees of Arabic patients was compared with that of 51 healthy knees of Muslim patients and 83 osteoarthritic knees in non-Arabic patients. The range of flexion of the osteoarthritic knees in the Arabic patients matched that of the healthy control knees, but was significantly better than that of the osteoarthritic knees in the non-Arabic patients. There was also a statistically significant difference between the mean extension deficit of the two groups with osteoarthritis. Exercises may help to prevent restriction of movement in osteoarthritis of the knee.

Adult↗

PubMed1998

Cartilage changes caused by a coronal surface stepoff in a rabbit model.

Coronal stepoffs of 0.5 mm (equal to the cartilage height) were created on the medial femoral condyles of adult, skeletally mature rabbits as a model for articular surface incongruity. After 3, 6, 12, and 24 weeks, tissue was analyzed histologically using hematoxylin and eosin and Safranin O staining, autoradiographs were made of the femoral condyles, and immunohistologic analysis was done for 3-B-3(-) and 7-D-4 chondroitin sulfate epitopes. An overlapping flap from the high toward the low side and an increase of the cartilage height on the low side of the defect were observed as permanent features of adaptation throughout the entire followup. Significant degeneration was not seen around the lesion or in the tibial cartilage opposing a stepoff defect. Autoradiography showed a three-phase response to the lesion: an early increase in radiolabeled sulfate (35SO4) uptake, a sharp decline of 35SO4 uptake, and finally a late recovery of the autoradiographic signal indicating partial recovery of proteoglycan synthetic activity. After an early increase, immunohistologic analysis for 3-B-3(-) showed a subsiding tendency by 24 weeks, and the staining with 7-D-4 remained elevated uniformly in the vicinity of the lesion. A rabbit femoral stepoff defect with an offset of 0.5 mm may remodel and not lead to degeneration within the first 6 months after injury in a stable joint.

Adaptation, Physiological↗

PubMed1995

Effects of valgus tibial angulation on cartilage degeneration in the rabbit knee.

Thirteen adult female rabbits underwent unilateral osteotomy of the proximal tibia. In nine animals, 30 degrees of valgus angulation was created; in four animals, osteotomy without angulation was performed. After a 12-week survival period, the knee joints were processed for histology by staining with hematoxylin and eosin and safranin O. Additionally, the chondroitin sulphate epitopes 3-B-3(-) and 7-D-4 were evaluated immunohistochemically as markers of osteoarthritis. Changes of the articular surface of the tibia were visualized by scanning electron microscopy. Light microscopic evaluation by the Mankin et al. scoring system revealed mild or moderate damage of the cartilage in the lateral compartment of angulated extremities when compared with the control side. Immunohistology with the monoclonal 3-B-3 and 7-D-4 antibodies showed no increased expression of these epitopes in the lateral compartments of the knee. Scanning electron microscopic evaluation of the tibial surfaces revealed slight surface damage localized to the central, weight-bearing portion of the lateral tibial plateau of angulated extremities. Angulation of 30 degrees led to only mild degenerative changes of the cartilage. These results indicate that, in the short term, cartilage has considerable capacity to withstand the effects caused by severe angulation of the limb.

Animals↗

PubMed1993

[Results of osteotomies in the management of valgus gonarthrosis].

Authors report on the result of correction osteotomies in 31 cases of gonarthrosis, developed in consequence of valgus deformity. In 12 cases high tibial osteotomy, in 19 supracondylar femoral osteotomy were performed. The result was excellent in 15, good in 10 and poor in 6 patients. Decisive factors of the favourable result were partly the correction of the femorotibial valgus to around the physiological values, partly the horizontalization of the articular surface. In overcorrection the results deteriorate. The medial tilt of the tibial articular surface leads to the progression of the arthrosis. Supracondylar femoral osteotomy was found especially successful in the treatment of valgus gonarthrosis. High tibial osteotomy is suggested only in selective cases.

Adolescent↗

PubMed1992

[Early synovectomy in the treatment of juvenile rheumatoid arthritis].

Authors report on the results of 15 synovectomies of the knee for iligoarticular juvenile rheumatoid arthritis. The operation was performed in every case in the early stage before the development of the radiological destruction. Excellent and good results were obtained in 11 cases; in 4 cases the operation was unsuccessful. It is stated that there is good chance to prevent destruction of the knee with juvenile rheumatic arthritis with an early synocvectomy. The operation is suggested after 6 years of age. The key of the good result is the early intensive mobilization of the joint.

Adolescent↗

PubMed1992

[Management of metatarsalgia using Helal's method for metatarsal osteotomy].

Authors report on the result of Helal's metatarsal osteotomies performed on 62 feet of 48 patients for metatarsalgia. In 85 per cent the result proved to be excellent, in 15 per cent there was no improvement. Analysing the causes of the postoperative complaints they call attention to the overload of the marginal arches and to the metatarsalgia developing on the non osteotomized neighbouring arch. These complaints appeared in 1/3 of their material and could be generally well influenced with conservative treatment.

Adolescent↗

PubMed1991

[Management of varus knee arthrosis by high tibial osteotomy].

Authors made a follow-up of 69 varsus knee arthrosis treated with high tibial osteotomy. Beside the general results the effect of the severeness of the arthrosis before the correction and that of the gain of the axial correction on the result were also investigated. 56 (81 per cent) of the reexamined patient reported excellent or good results. The ratio of the successful operations was even higher in cases in which the femorotibial axis was corrected to physiological valgus (95 per cent). The best prognosis of the osteotomy is in the early stage of arthrosis (Ahlbäck 0-II). In cases of the more advanced process the ratio of the unsuccessful cases increases. In consequence it is stated that the best results can be expected after osteotomies performed in the early stage and leading to the physiological femorotibial valgus position.

Arthritis, Rheumatoid↗