PubMed Health⌕ Search

Biomedical subjects

N S Mitchell

Publications and source records attributed to N S Mitchell.

8 recordsLinked to original sources
PubMed1990

Electron microscopic evaluation of the occurrence of matrix vesicles in cartilage.

Troubled by variations in the descriptions of shape, appearance, and content of matrix vesicles and the conflicting reports of increased numbers of vesicles in the mineralizing regions of the growth plate contrasted with larger numbers in the resting zone, we embarked on a review of matrix vesicles in the growth plate using a comparison of different fixation techniques. We found matrix vesicles resembling cell debris at all levels of the growth plate, with no particular association with mineral. Lipid bodies surrounded by a membrane of proteoglycan have also been seen in large numbers. The cell debris-like matrix vesicles have been the common finding in reports of digested centrifuged cartilage and may represent cytoplasmic processes. Lipid bodies surrounded by proteoglycan may be similar to the membrane-bound vesicle described by Ali (Fed. Proc., 35:135-142, 1987) and by Bonucci (Clin. Orthod., 78:108-133, 1971).

Animals↗
PubMed1988

Colloidal chromic phosphate 32P synovectomy in antigen-induced arthritis in the rabbit.

Radioisotopes have been employed in the therapy of chronic arthritis, in particular, rheumatoid arthritis for many years. A variety of isotopes have been popularized, and in the last ten years a colloidal solution of radioactive chromic phosphate 32P has been in use apparently with equivalent efficacy to others such as 169erbium, 90yttrium, and 165dysprosium. No controlled studies on this modality have been reported and few animal studies were found. The efficacy of therapeutic doses of 32P as a medical synovectomy and its effect on rabbit joints with antigen-induced arthritis were observed in 62 arthritic knee joints in 31 adult rabbits treated on one side with 0.1 microCi of 32P, the opposite serving as control. The animals were observed over a period of 11 months and examined by histologic and biochemical means. The synovium showed no evidence of radiation necrosis in treated joints. Cartilage of treated and control joints showed similar changes consistent with chronic arthritis, persistent synovitis, progressive chondrocyte degeneration, and decreased matrix metachromasia. The radiosynovectomy had neither removed synovium nor protected the cartilage. Its efficacy in humans is therefore questionable.

Animals↗
PubMed1978

Leg amputation.

Explore the source record for details and available documents.

Amputation, Surgical↗
PubMed1978

Changes in proteoglycan and collagen in cartilage in rheumatoid arthritis.

Articular cartilage from thirteen patients with rheumatoid arthritis was studied by both light and electron microscopy using recently developed staining techniques for proteoglycan. Normally proteoglycan is concentrated about active chondrocytes, but in the cartilage from these patients it was found to be diminished about most of the chondrocytes while it was increased around a few. Fragmentation of collagen and phagocytosis of the fragments by chondrocytes were also noted. This dissolution of collagen was associated with loss of proteoglycan in the matrix. These findings are consistent with the variable nature of the rheumatoid destructive process and appear to be morphological reflections of biochemical changes which formerly were thought to occur in this disease only at the cartilage-pannus junction.

Arthritis, Rheumatoid↗
PubMed1977

Classification of degenerative arthritis.

It is suggested that the former division of degenerative arthritis into idiopathic types and those secondary to some disease process is no longer valid. Recent studies have indicated that abnormal concentrations of force on cartilage lead to the development of this disease. A classification is presented that is based on the assumption that the process is initiated by abnormal concentrations of force on normal cartilage matrix, normal concentrations of force on abnormal cartilage matrix or normal concentrations of force on normal cartilage matrix that is supported by bone of abnormal consistency.

Arthritis↗