PubMed Health⌕ Search

Biomedical subjects

R M Stevens

Publications and source records attributed to R M Stevens.

7 recordsLinked to original sources
PubMed1992

Characterization of type V collagenase (gelatinase) in synovial fluid of patients with inflammatory arthritis.

Gelatin degrading matrix metalloproteinases in synovial fluid from 21 patients with inflammatory arthritis were shown to consist of two distinct gene products, 92 and 70 kDa gelatinases. The gelatinolytic activity of 92 kDa enzyme, which is released from stimulated neutrophils, was positively correlated to neutrophil count in the fluid. By contrast, 70 kDa molecule did not correlate with neutrophil cell count. Purification of these enzymes revealed they could degrade type XI collagen, a cartilage component resistant to interstitial collagenase. The elevated levels of 92 kDa gelatinase in rheumatoid arthritis samples compared to osteoarthritis suggest a role of this enzyme in cartilage destruction.

Adult↗
PubMed1990

Human neutrophil collagenase. A distinct gene product with homology to other matrix metalloproteinases.

We have identified and sequenced a cDNA encoding human neutrophil collagenase from a lambda gt11 cDNA library constructed from mRNA extracted from the peripheral leukocytes of a patient with chronic granulocytic leukemia. The library was screened with an oligonucleotide probe constructed from the putative zinc-binding region of fibroblast collagenase. Eleven positive clones were identified, of which the one bearing the largest insert (2.2 kilobases (kb)) was sequenced. From the nucleotide sequence of the 2.2-kb cDNA clone we have deduced a 467-amino acid sequence representing the entire coding sequence of the enzyme. The deduced protein was confirmed as neutrophil collagenase by conformity with the amino-terminal sequence analyses of three tryptic peptides of purified neutrophil collagenase. The cDNA clone hybridizes to a 3.3-kb mRNA present in RNA extracted from human bone marrow but did not hybridize with RNA isolated from U937 cells induced to differentiate with phorbol myristate acetate. Neutrophil collagenase was found to possess 57% identity with the deduced protein sequence for fibroblast collagenase with 72% chemical similarity. Certain regions of the molecule, including the putative zinc-binding region, are highly conserved. When compared with the published sequence for fibroblast collagenase, neutrophil collagenase contains four additional sites for glycosylation. Medium from COS-7 cells transfected with a pcDNA1 eucaryotic expression vector containing cDNA for neutrophil collagenase degraded type I collagen into the three-quarter, one-quarter fragments characteristic of mammalian interstitial collagenase activity. Thus, definitive evidence based on the cDNA sequence confirms the neutrophil collagenase is a distinct gene product and a member of the family of matrix metalloproteinases.

Amino Acid Sequence↗
PubMed1977

The effect of the Valsalva maneuver on echocardiographic dimensions in man.

Physiologic changes in the circulatory system caused by performing the Valsalva maneuver are blunted or absent in patients with congestive heart failure. Previously there has been no noninvasive method for examining cardiac chamber size during this maneuver. M-mode echocardiography was used to evaluate possible changes in cardiac chamber dimensions in 12 normal subjects (group I) and 15 patients with cardiovascular disease (group II). In group I, the left ventricular end-diastolic dimension decreased 11.2% (+/- 1.5%) and the end-systolic dimension 9.5% (+/- 1.32%), with a fall in stroke volume of 29%. The left atrial (LA) dimension decreased 30%. In group II, only the response of the LA dimension is reported. There was a diminished response to Valsalva related to the severity of congestive heart failure. Patients in NYHA classes III and IV decreased LA dimension by only 3.8%, significantly less (P less than 0.001) than those in classes I and II who had essentially normal responses. Echocardiographically-determined changes in left atrial size in response to the Valsalva maneuver may provide an objective, noninvasive means of evaluating and following patients with suspected or proven congestive heart failure. Possible mechanisms for the changes observed are discussed.

Adult↗
PubMed1975

Echocardiography.

Explore the source record for details and available documents.

Cardiomegaly↗
PubMedDate not supplied

Treatment of arthritis with topical capsaicin: a double-blind trial.

The neuropeptide substance P has been implicated in the pathogenesis of inflammation and pain in arthritis. In this double-blind randomized study, 70 patients with osteoarthritis (OA) and 31 with rheumatoid arthritis (RA) received capsaicin (a substance P depletor) or placebo for four weeks. The patients were instructed to apply 0.025% capsaicin cream or its vehicle (placebo) to painful knees four times daily. Pain relief was assessed using visual analog scales for pain and relief, a categorical pain scale, and physicians' global evaluations. Most of the patients continued to receive concomitant arthritis medications. Significantly more relief of pain was reported by the capsaicin-treated patients than the placebo patients throughout the study; after four weeks of capsaicin treatment, RA and OA patients demonstrated mean reductions in pain of 57% and 33%, respectively. These reductions in pain were statistically significant compared with those reported with placebo (P = 0.003 and P = 0.033, respectively). According to the global evaluations, 80% of the capsaicin-treated patients experienced a reduction in pain after two weeks of treatment. Transient burning was felt at the sites of drug application by 23 of the 52 capsaicin-treated patients; two patients withdrew from treatment because of this side effect. It is concluded that capsaicin cream is a safe and effective treatment for arthritis.

Administration, Topical↗