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Biomedical subjects

D B Myers

Publications and source records attributed to D B Myers.

At least 37 records · Page 2Linked to original sources
PubMed1980

Subcellular particles in synovial fluids and synovial cells.

Membranous particles of mycoplasma-like appearance (100 to 300 nm in diameter) and non-membranous particles which are viral-like (20 to 80 nm in diameter) were observed in negatively-stained preparations of synovial fluid pellets from patients with rheumatoid arthritis (RA), osteoarthrosis (OA) or psoriatic arthritis (PA). The incidence of positive fluids were: membranous particles--22/28 (RA), 7/11 (OA), 1/3 (PA); non-membranous particles--12/28 (RA), 1/11 (OA), 1/3 (PA). Eight of the RA fluids, one OA and one PA fluid were positive for both types of particle. The observation of an increased frequency of viral-like particles in RA synovial fluids compared to OA and PA fluids is of possible aetiological interest. Viral-like particles were also observed in the nuclei of rheumatoid synovial macrophage syncytia by electron microscopy of ultra-thin sections of cultured cells.

Arthritis↗
PubMed1980

Serum copper and zinc in rheumatoid arthritis and osteoarthritis.

Serum copper, zinc and caeruloplasmin levels were measured in 49 patients with active rheumatoid arthritis, in 33 patients with osteoarthritis and a group of blood donor controls. Serum copper and caeruloplasmin levels in the osteoarthritic patients were significantly higher and serum zinc levels significantly lower than in the blood donor controls. Although these differences could not be accounted for on the basis of age or drug administration neither did they correlate with a radiological grading of disease severity. Copper and caeruloplasmin levels were raised in the rheumatoid group as compared to both osteoarthritic and control groups. These were strong correlations between serum copper, caeruloplasmin, ESR and alpha 1 globulin levels in the rheumatoid patients. Although caeruloplasmin-bound copper accounted for most of the elevation in serum copper levels in the rheumatoid group, the calculated non-caeruloplasmin bound copper level was also elevated in rheumatoid, as compared to osteoarthritic patients. Serum zinc levels in the rheumatoid group were lower than in the control group but not significantly different to those in the osteoarthritic group.

Adult↗
PubMed1980

Collagen content in human ulnar nerve.

A quantitative analysis of ulnar nerve collagen in the arm and forearm was undertaken in nine subjects. While endoneurial collagen was found to be significantly increased within the cubital tunnel, extrafascicular collagen did not increase at the elbow except in two nerves showing fusiform enlargements. Renaut bodies increased in frequency at sites of high endoneurial collagen content. Morphological determinations of cross-sectional area along the ulnar nerve did not correlate with quantitative collagen data.

Adult↗
PubMed1980

Collagen and protein content of autopsied peripheral nerve.

Rat sciatic nerve was assayed for total collagen and total protein both immediately post-mortem and at weekly intervals after death. No significant difference was found in collagen and protein content between corresponding nerve segments assayed fresh and up to 4 weeks post mortem. However, variation was found in peripheral nerve collagen content between adjacent lengths of sciatic nerve. These results suggest that peripheral nerve collagen and protein remain stable under cool-room conditions for several weeks after death.

Animals↗
PubMed1980

A study of the structural response of wet hyaline cartilage to various loading situations.

A direct view has been obtained of the manner in which the fibrous components components and chondrocytes in hyaline cartilage respond to the application of uniaxial tensile loading and plane-strain compressive loading. A micro-mechanical testing device has been developed which inserts directly into the stage of a high-resolution optical microscope fitted with Nomarski interference contrast and this has permitted simultaneous morphological and mechanical observations to be conducted on articular cartilage maintained in its wet functional condition. Aligned and crimped fibrous arrays surround the deeper chondrocytes and can be observed to undergo well-defined geometric changes with applied stress. It is thought that these arrays may act as displacement or strain sensors transmitting mechanical information from the bulk matrix to their associated cells thus inducing a specific metabolic response. The process of tissue recovery following sustained high levels of compressive loading can also be observed with this experimental technique.

Animals↗
PubMed1980

Hand grip function in patients with rheumatoid arthritis.

A new electronic dynanometer was developed and used to determine hand grip function in patients with rheumatoid arthritis. Triplicate pressure-time recordings of grip for each hand were used to calculate maximum grip strength, time required to reach 95% maximum grip strength (t95), total work and maximum power output. Measurements were done on 30 women aged 32 to 74 years (mean, 53 years) who had rheumatoid arthritis and 20 healthy women aged 37 to 69 years (mean, 50 years). The values obtained for patients and healthy women showed that the dominant hand was stronger than the nondominant hand in all women. However, all tests in patients with arthritis indicated decreased function and strength, the relative decrease being greater for nondominant hands compared with dominant hands. This new approach to measurement of hand grip function may provide better discrimination in the quantitative assessment of morning stiffness and response to changes in drug therapy. The time required to achieve 95% of maximum grip strength and maximum power outputs in particular appear to be more sensitive indicators of function than the standard maximum grip strength measurement.

Adult↗
PubMed1979

In vitro aggregation of mouse peritoneal exudate cells.

(1) Immunological mechanisms which cause macrophage agglutination in vitro have been investigated. (2) Quantitative differences in the agglutinating properties of sero-positive rheumatoid sera and normal sera were found. (3) NZB X W mouse peritoneal macrophages differed from normal (NZCW) mouse peritoneal macrophages in susceptibility to agglutination. These quantitative differences could be explained by NZB X W macrophages carrying a surface immunoglobulin component which increased agglutination by rheumatoid sera. (4) Antimacrophage antibody was more effective in rendering macrophages susceptible to the agglutinating effect of antiglobulins than was heat-aggregated gamma globulin.

Agglutination Tests↗
PubMed1977

The analysis of collagen in glutaraldehyde-fixed, osmicated peripheral nerve.

Glutaraldehyde fixation and osmication of rat sciatic nerve and human sural nerve did not appreciably alter the apparent weight of collagen in nerve fasciculi as determined by hydroxyproline analysis of hydrolysed samples. The collagen content of autopsied peripheral nerve is unaltered at least up to 24 h after death. The mean endoneurial weight of collagen per fascicle in rat sciatic nerve was 123 mug (all results expressed for 1 cm length). In human sural nerve the mean weight was 57 mug and the mean fascicular volume 1.75 mm3. Human endoneurial collagen fibrils gave a unimodal distribution of diameters with a peak at 40 nm.

Animals↗
PubMed1977

Binding of sodium [195Au]aurothiomalate to Mycoplasma arthritidis.

The binding of sodium [195Au]aurothiomalate (ATM) to whole cells of Mycoplasma arthritidis has been measured within the temperature range of 4 to 53 degrees C. The time course (kinetics) and the effect of varying the total concentration of free ATM in the suspension at 37 degrees C were also measured. The extent of binding at 37 degrees C leveled off after 30 min at approximately 65 nCi of [195Au]ATM per mg of membrane protein. The amount of ATM bound per cell appeared to be directly proportional to the concentration of free ATM in the range of 0.25 to 0.60 muCi of [195Au]ATM per ml. An Arrhenius plot showed two distinct regions with slopes of -0.56 degrees K/mg of protein (5 to 22 degrees C) and -2.78 degrees K/mg of protein (22 to 53 degrees C). The break in the Arrhenius plot corresponds to a temperature known to be related to a sudden change in mycoplasma membrane fluidity. Estimations of Scatchard binding constants and number of binding sites per membrane protein molecule resulted in 0.8 to 1.4 sites per molecule in the intact organisms compared to 1.4 to 1.8 sites in membrane fragments. The latter were purified by repeated washings in phosphate-buffered saline after alkaline lysis of the cells. It is suggested that ATM reacts with available protein sulfhydryl groups in the mycoplasmal membrane.

Bacterial Proteins↗
PubMed1976

Electron microscopic autoradiography of 35SO4-labelled material closely associated with collagen fibrils in mammalian synovium and ear cartilage.

Electron microscopic autoradiography of connective tissue obtained from mice and rabbits previously injected with 35SO4 indicated that sulphated proteoglycans are localized on collagen fibrils. Ruthenium Red-positive transverse belts surrounding fibrils near the a-bands were heavily labelled, but fine lateral filaments of Ruthenium Red-positive material were not. These filaments, which interconnect collagen fibrils in a variety of connective tissues may represent linear aggregations of hyaluronic acid, glycoproteins and non-sulphated or long-lived sulphated proteoglycans.

Animals↗
PubMed1976

Preliminary observations on an isolate from synvoial fluid of patients with rheumatoid arthritis.

A very slow-growing micro-organism has been isolated from the synovial fluid of patients suffering from rheumatoid arthritis. This organism exhibits some of the properties of a mycoplasma such as growth in the presence of penicillin, and the requirement of serum and yeast, but generally does not behave like any known species of this group. Colonies resemble some types of T-mycoplasma in morphology and size. Scanning electron microscopy showed that the size of the components of these colonies was exceedingly small.

Arginine↗