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Biomedical subjects

J M Cloutier

Publications and source records attributed to J M Cloutier.

45 records · Page 3Linked to original sources
PubMed1985

Human rheumatoid arthritic cartilage and its neutral proteoglycan-degrading proteases. The effects of antirheumatic drugs.

Measurements were made of the neutral proteoglycan-digesting protease activity in the cartilage matrix breakdown observed in the rheumatoid arthritic process. Normal knee (tibial plateau) cartilage specimens were obtained from 7 fresh cadavers and 29 cartilage specimens were obtained from 23 patients diagnosed as having rheumatoid arthritis (RA). The total neutral metalloproteoglycan-degrading enzyme (NMPE) activity in RA cartilages exhibited roughly an eightfold elevation over that of control subjects. The active form of the NMPE for diseased cartilage was higher than that observed for normal cartilage, but was not statistically different. A very low level of activity was detected for serine proteases and no variation was observed between normal and diseased cartilages. Data obtained from RA cartilages were also analyzed with respect to the relationship between enzyme activities and the patients' medications. Four groups of patients were then selected according to their drug treatments: S + G patients received steroid and gold therapy; S patients received steroids only; NS + NG patients did not receive steroid or gold therapy; G patients received gold therapy alone. The total NMPE activity for each of these groups remained at a very high level. The active enzyme activity measured in S + G and S patients was decreased to a level not different from that of normal controls. Specimens from NS + NG patients presented a significantly higher level of the active form of the enzyme (P less than 0.05) when compared with either normal controls, S + G, or S patients. No significant difference was noted in the level of serine protease activity between the RA cartilage and normal cartilage.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Neutral proteases capable of proteoglycan digesting activity in osteoarthritic and normal human articular cartilage.

Proteases have been postulated to account for the progressive disappearance of matrix proteoglycans in osteoarthritic (OA) cartilage. The digestion of endogenous proteoglycans by neutral proteases in human OA cartilage homogenates has been measured and compared with that of normal age-matched controls. Cartilage was obtained from 16 patients at the time of knee arthroplasty and from 7 accident victims. Tissue blocks were cut from the tibial plateau; part was used for histologic grading of the severity of OA and part was homogenized for the quantification of neutral metallo- and serine protease activities, based on the release of digested products from endogenous proteoglycans. Total metalloprotease activity (latent plus active forms) was elevated 3- to 10-fold in all diseased cartilage. This elevation was already significant in mild disease, but was greatest in samples of moderate to severe disease. The active form of the enzyme was highest at the center of erosions and decreased in the margins of the plateau. The digestion of proteoglycans, as distinct from their mere release from the tissue, was demonstrated by chromatography on Sepharose-CL2B and by large pore electrophoresis. Serine protease activity on proteoglycans was much lower than that of metalloprotease. The mean activity was highest in mild disease and declined in the severe disease samples, but the difference between these 2 groups and the controls was not statistically significant. The results of this study are consistent with the hypothesis that the neutral metalloproteases of cartilage are involved in the degradation of proteoglycans in osteoarthritis.

Adult↗
PubMed1983

Results of total knee arthroplasty with a non-constrained prosthesis.

A non-constrained total knee prosthesis designed at St. Luc Hospital, Montreal, has been used there since 1977. The geometry of its femoral component simulates the normal anatomy of the knee and the flat articular surfaces of its tibial component allow unconstrained rotation, rolling, and sliding motion, as dictated by the retained cruciate ligaments. The results achieved in the first 107 consecutive arthroplasties (in eighty-three patients) were evaluated after a minimum follow-up of two years (range, two to four and one-half years). Using the knee-rating system of The Hospital for Special Surgery, 91 per cent of the knees had an excellent or good result. In ninety-eight knees the preoperative pain was adequately relieved and the limb was in physiological valgus alignment. One hundred and four knees had normal medial-lateral stability in extension, and three were unstable. The average postoperative arc of flexion was 102.8 degrees. Sixty-three patients (76 per cent) could ascend and descend stairs normally, and gait studies on seventeen of these patients (twenty-three involved knees) demonstrated that the flexion arc of the knee while the patients were ascending and descending stairs was the same as that of normal controls. Three knees had a deep wound infection and one knee had aseptic loosening of the femoral component.

Adult↗
PubMedDate not supplied

Proteoglycan structural changes in human rheumatoid articular cartilage.

Human rheumatoid arthritic (RA) cartilage contains elevated levels of proteolytic enzymes in which the metalloproteases are believed to be the prime enzyme system involved in cartilage metabolism. We examined the effects of these enzymes and the serine proteases on endogenous proteoglycans (PGs) and newly synthesized PGs of seven RA cartilages. The data was further analyzed with regard to the therapy received by the patients prior to surgery. A structural heterogeneity among the PGs from RA cartilage was found, and two subsets were distinguished. While in the first subset more than 35% of the PGs were in aggregate form, no appreciable amount of PG aggregate was found in the second subset. Interestingly, in all but one specimen the subsets appeared to be a function of prior therapy received by the patients. In subset I patients had received prednisone and/or DMARD in addition to NSAIDs, while those from subset II had all received NSAIDs only, with one exception. Our findings also suggest that PG structure alterations could result from the action of already active and APMA-activated metalloproteases; these reduced the PG aggregation capability and caused extensive cleavage in the PG core protein. The serine proteases did not seem to play a major role. Moreover, when the endogenous latent metalloproteases were activated with APMA, high-density PGs (the A1D1 fraction) showed a reduction in their capacity to reaggregate, and in their hydrodynamic size. Using an immunological technique we demonstrated the presence, in subset I, of the hyaluronan binding region domain (HABR) of the core protein. For subset II this domain could not be found.(ABSTRACT TRUNCATED AT 250 WORDS)

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