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Biomedical subjects

K M Cooper

Publications and source records attributed to K M Cooper.

At least 37 records · Page 2Linked to original sources
PubMed1984

Chymopapain, chemonucleolysis, and nucleus pulposus regeneration. A biochemical and biomechanical study.

In the adult mongrel dog, in vivo injection of chymopapain into the intervertebral disc resulted, at two weeks, in disc space narrowing. However, [35S]sulfate labeling and proteoglycan characterization demonstrate that the nucleus retains the ability to synthesize proteoglycans, although they were degraded rapidly by residual proteolytic activity. Three months following chymopapain treatment, the intervertebral dog disc shows that an increase in disc height, return of nuclear material, and proteoglycan aggregate is present. At six months following chymopapain treatment, proteoglycans of similar characteristics to normal canine intervertebral disc are identified with a glucosamine/galactosamine ratio approaching normal values. Biomechanically, the short-term (30-120 minutes) in vitro effects of chymopapain appear to be the same as the carrier causing increased disc height, stiffness values, and creep rates. In the vivo study, after three weeks, chymopapain-injected discs had significant reductions in disc height and compressive stiffness, but the creep rate was increased substantially. However, at three months postinjection, these biomechanical properties began to reverse and approached those of the uninjected controls. The observations reported in this study suggest that chymopapain has a profound but reversible effect on normal canine intervertebral disc. The radiographic narrowing of the intervertebral disc following chymopapain injection correlates with loss of proteoglycan content, structure, and biomechanical properties. The restoration of normal disc height following chymopapain injection is explained by reconstitution of normal intervertebral disc. EDTA and cysteine used alone have no discernable in vivo enzymatic effect on intervertebral disc proteoglycan biochemistry. Chemonucleolysis with chymopapain would appear less likely to alter permanently proteoglycan biochemistry and the biomechanical properties of the disc than surgical excision in experimental animals.

Animals↗
PubMed1984

Cutaneous vasculitis and immune complexes in severe bronchiectasis.

Four patients with severe bronchiectasis (chronic bronchial suppuration) are described who developed cutaneous lesions associated with exacerbations of their respiratory disease. The skin abnormalities consisted of purpuric lesions in three patients and an erythematous vasculitis in one. Circulating immune complexes were present in all patients and in three skin biopsy specimens showed deposition of C3, IgG, and IgA in dermal blood vessels. Haemophilus influenzae had been isolated from the sputum of all four patients and in two patients was present at the time the cutaneous lesions appeared. It is suggested that local immune complex deposition was responsible for the skin lesions which occurred during acute exacerbations of bronchiectasis.

Aged↗
PubMed1983

Critical aspects of immune complex assays employing polyethylene glycol.

Treatment of artificial immune complexes (ICs) with 2.5% polyethylene glycol (PEG)--conditions under which C1q-binding activity is routinely measured in the fluid phase--produced marked changes in molecular size as determined by Sepharose 6B chromatography. The effect of PEG on the C1q-binding capacity of ICs, was therefore investigated using a solid phase (SP) system. PEG enhanced the binding of aggregated human gammaglobulin (AHG) and artificial ICs to SP-C1q and, in reverse experiments, also increased the binding of C1q to SP-AHG. The degree of enhancement varied according to the Ag:Ab ratio employed; the binding of ICs formed in moderate Ab excess was only modestly enhanced but that of complexes formed at slight Ab excess, equivalence and Ag excess was markedly elevated. The profile of PEG-induced enhancement of binding paralleled that of similar ICs in the C1q fluid phase system, suggesting that C1q binding in the latter may be influenced by PEG. However, the C1q-binding activity of in vivo-formed ICs seemed to be relatively unaffected by PEG since enhanced binding was comparable in control and pathological sera. The results indicate that PEG causes cross-linking and aggregation of ICs (and possibly other serum proteins) which may alter their biological activity and hence influence the results of IC assays that employ this agent.

Antigen-Antibody Complex↗
PubMed1983

Limitations of immune complex measurements in colorectal disease.

Three techniques (Clq, Raji and L1210 binding assays) alleged to measure circulating immune complexes (ICs) were applied to the sera of 101 patients with colorectal disease (54 carcinoma; 23 inflammatory; 13 benign tumour and 11 miscellaneous) at the time of diagnostic or definitive surgery, and 58 healthy adult controls. Elevated levels in the pathological sera were observed by all 3 methods in order of sensitivity: Raji greater than Clq greater than L1210. However, none of them differentiated between benign, inflammatory and neoplastic conditions nor, in the case of colorectal carcinoma, was there any correlation with stage of disease. With the exception of Raji v. L1210 (r = 0.43, P less than 0.001), correlations between the various assays were poor and levels of serum carcinoembryonic antigen (CEA) did not correlate with ICs measured by any of the techniques. Indeed, the IC assays were even less discriminatory than CEA, which was elevated mainly in the serum of carcinoma patients and which was positively correlated with serum gamma-glutamyl transpeptidase (gamma GT) (r = 0.42, P less than 0.005). The data suggest that the lack of concordance between the IC assays is a reflection of heterogeneity among ICs, interfering factors present in pathological sera, or both. Thus the IC assays deployed here have neither diagnostic nor prognostic utility in colorectal disease at this time, and immunochemical characterization of the serum reactive material detected by the different assays is required.

Adult↗
PubMed1983

An improved automated periodate-resorcinol method for the determination of sialic acid.

A periodate-resorcinol method for bound sialic acid using the Technicon Autoanalyzer II is presented. It has a sensitivity similar to the manual method, is linear between 5 and 65 nmol/ml, requires less than 0.2 ml of sample, and can be run at the rate of 70 samples/h. Little cross-reaction with common matrix and cell components was found. The method is compatible with many commonly used volatile and nonvolatile chromatographic buffers. The use of a bound sialic acid standard such as N-acetylneuraminyl lactose is recommended.

Autoanalysis↗
PubMed1983

Chymopapain, chemonucleolysis, and nucleus pulposus regeneration.

UNLABELLED: In the adult mongrel dog, in vivo injection of chymopapain into the intervertebral disc resulted in disc-space narrowing at two weeks, with a complete loss of proteoglycan (as indicated by safranin-O staining) from the nucleus pulposus, the cartilaginous end-plates, and the annulus fibrosus. As demonstrated by [35S]sulphate-labeling and proteoglycan isolation, the nucleus pulposus retained the ability to synthesize proteoglycans, but these were degraded by endogenous proteolytic activity. Three months after chymopapain treatment the intervertebral disc showed an increase in height. There was a return of intense safranin-O staining in the annulus and the cartilaginous end-plates, and very prominently in the nucleus. The proteoglycans that were present were recovered as aggregates, with the proteoglycan monomer being slightly larger than in the controls. Six months after chymopapain treatment the intervertebral disc had increased further in height, and normal histology had been restored. The chemical composition and physical properties of the proteoglycans that were isolated from the nucleus pulposus were essentially the same as those from the controls. These observations suggest that the nucleus can regenerate following the injection of chymopapain. CLINICAL RELEVANCE: Our observations demonstrate that chymopapain has a profound but reversible effect on the intervertebral disc. The radiographic narrowing of the intervertebral disc following chymopapain injection correlates with the loss of proteoglycan content and structure. The restoration of normal disc height following chymopapain injection is explained by reconstitution of the intervertebral disc with normal proteoglycans. In experimental animals, chemonucleolysis with chymopapain appears to be less likely than surgical excision to permanently alter the biochemistry of the nucleus pulposus.

Animals↗
PubMed1983

Reactivity of low molecular weight material in cellular immune complex assays.

A major difference in molecular size of material reactive in the C1q binding assay and two cellular assays (Raji and L1210) for immune complexes, is reported. Elevated C1q binding of pathological sera was associated with material in the range 7-19S, as determined by Sepharose 6B chromatography of sera from patients with chronic inflammatory and neoplastic lung diseases. By contrast, reactivity of identical sera in the Raji and L1210 assays was linked predominantly with material of molecular size 7S. Dissociation of immune complexes on storage and/or in consequence of the chromatographic procedure was effectively discounted. Furthermore, differential binding of 7S IgG fractions tested at a standard concentration indicated that reactivity in either test was not attributable to non-specific binding of IgG. In a previous study, saturation of FcR (on L1210 and Raji) and C3R (on Raji only) by heat-aggregated IgG failed to distinguish whether binding directly involved these receptors or other cell surface components. In the present investigation, no firm correlations emerged between reactivity in the two tests and possible candidate antibodies reactive with cell surface components such as anti-lymphocyte and anti-nuclear antibodies. It is therefore suggested that low molecular weight binding may be attributable to more than one factor including 7S IgG (immune complex dissociated, or otherwise), autoantibodies, IgG-C3 complexes and possibly very small immune complexes (Ag1, Ab1). The assumption that Raji and L1210 and possibly other cellular assays detect only high molecular weight immune complexes is questionable and the need for further characterization of other reactive material is emphasized.

Antibodies, Antinuclear↗
PubMed1982

Alteration of in vivo cellulose ribbon assembly by carboxymethylcellulose and other cellulose derivatives.

In vivo cellulose ribbon assembly by the Gram-negative bacterium Acetobacter xylinum can be altered by incubation in carboxymethylcellulose (CMC), a negatively charged water-soluble cellulose derivative, and also by incubation in a variety of neutral, water-soluble cellulose derivatives. In the presence of all of these substituted celluloses, normal fasciation of microfibril bundles to form the typical twisting ribbon is prevented. Alteration of ribbon assembly is most extensive in the presence of CMC, which often induces synthesis of separate, intertwining bundles of microfibrils. Freeze-etch preparations of the bacterial outer membrane suggest that particles that are thought to be associated with cellulose synthesis or extrusion may be specifically organized to mediate synthesis of microfibril bundles. These data support the previous hypothesis that the cellulose ribbon of A. xylinum is formed by a hierarchical, cell-directed, self-assembly process. The relationship of these results to the regulation of cellulose microfibril size and wall extensibility in plant cell walls is discussed.

Acetobacter↗
PubMed1982

Heterogeneity of circulating immune complexes in chronic lung diseases.

Circulating immune complex (IC) levels in sera from 58 healthy controls and a total of 212 patients with various chronic lung diseases were measured using 3 assays. Two complement-dependent assays (C1q fluid phase and Raji) and a complement-independent assay (L1210) were employed. The 3 assays generally revealed similar patterns of reactivity when control and pathological groups were compared, with the L1210 assay invariably demonstrating the lowest incidence of positive values in each group. The most significant elevations in IC levels were exhibited in bronchiectasis and bronchogenic carcinoma. However, within these two groups correlations between IC assays performed on individual sera were poor. Significant but weak correlations (p less than 0.01) were only observed for C1q vs Raji in bronchiectasis and C1q vs L1210 in bronchogenic carcinoma. Complement-binding ICs were present to a similar extent in both conditions. However, non-complement binding ICs were found to be more common in bronchiectasis. The relative sensitivity of the tests and the contribution of interfering factors to the disparity between the assays is discussed. However, the interpretation favoured is that the lack of correlation is primarily a reflection of the intrinsic heterogeneity of immune complexes formed under similar and dissimilar pathological conditions.

Animals↗
PubMed1981

C1q binding activity in the sera of patients with chronic lung diseases.

Sera from patients with chronic lung diseases were tested for the presence of immune complexes (ICs) by the 125I-C1q-binding assay. Contrary to earlier reports, modification of the test system by addition of heparin decreased rather than increased the ability of the test to discriminate between control and pathological sera. Using the unmodified system, elevated C1q-binding activity (C1qBA) was found in patients with asthma (18%), chronic bronchitis (18%), sarcoidosis (18%), fibrosing alveolitis (50%), bronchogenic carcinoma (52%) and bronchiectasis (67%). Studies with the reducing agent 2-mercaptoethanol (2-ME) suggested a role for IgM rheumatoid factor (RF) and/or IgG-containing complexes in the C1q-reactive material of sera from patients with bronchiectasis and bronchogenic carcinoma. In the latter two groups, C1qBA was found to correlate with serum levels of IgG and IgA but not with C3 and C4. A weak condition between levels of C-reactive protein (CRP) and C1qBA was found in the bronchogenic carcinoma group. Carcinoembryonic antigen (CEA) levels were elevated in all groups studied but no correlation with C1qBA was demonstrated, suggesting that CEA and CEA-ICs, if present, do not have an influence on the C1qBA of such sera. The results indicate that elevated serum C1qBA is a concomitant of both chronic inflammatory and neoplastic diseases of the lung but the extent of any similarity in the non-immunoglobulin components of the immune complexes in the respective conditions remains unknown.

Adolescent↗
PubMed1980

Cellulose biogenesis: Polymerization and crystallization are coupled processes in Acetobacter xylinum.

Calcofluor White ST, stilbene derivative used commerically as an optical brightener for cellulose, increased the rate of glucose polymerization into cellulose by resting cells of the gram-negative bacterium Acetobacter xylinum. This bacterium normally produces a ribbon of cellulose that is a composite of crystalline microfibrils. In concentrations above 0.1 mM, Calcofluor disrupts the assembly of crystalline cellulose I microfibrils and their integration into a composite ribbon by stoichiometric binding to glucose residues of newly polymerized glucan chains. Under these conditions, the rate of glucose polymerization increases up to 4 times the control rate, whereas oxygen uptake increases only 10-15%. These observed effects are readily reversible. If free Calcofluor is washed away or depleted below the threshold value by binding to cellulose as polymerization continues, ribbon production and the normal rate of polymerization resume. It is concluded that polymerization and crystallization are cell-directed, coupled processes and that the rate of crystallization determines the rate of polymerization. It is suggested that coupling must be maintained for biogenesis of crystalline cellulose I.

Journal Article↗
PubMed1979

Aggregated proteoglycan synthesis in organ cultures of human nucleus pulposus.

Proteoglycans isolated under associative conditions in the presence of protease inhibitors from human nucleus pulposus contained 17% aggregate and 83% non-aggregating monomer (Kav = 0.5 on Sepharose CL-2B). Isolated aggregate after reduction and alkylation was resolved into two components (Kav = 0.15 and 0.43) on Sepharose CL-2B. Labeled proteoglycans isolated from parallel samples pulsed with [35S]sulfate and chased for up to 18 h were present largely as aggregated material (up to 78%). Reduction and alkylation of the labeled samples gave a labeled proteoglycan monomer with Kav = 0.15. Both the labeled and unlabeled chondroitin sulfate chains had the same distribution on Sepharose CL-6B and equivalent molecular weights (Mr = 2.0 x 10(3)). After chondroitinase ABC digestion, the unlabeled keratan sulfate-protein core was polydisperse with a Kav = 0.38 on Sepharose CL-4B while the labeled keratan sulfate-protein core had a Kav = 0.05. This indicates that the newly synthesized proteoglycan had a large core protein and suggests that the proteoglycans present in nucleus pulposus are originally synthesized as large molecular weight, aggregating proteoglycans.

Humans↗
PubMedDate not supplied

An immunohistochemical study of the distribution of biotin in tissues of pigs and chickens.

An optimised indirect peroxidase-anti-peroxidase immunohistochemical technique was used to detect endogenous biotin in frozen tissue sections from biotin-supplemented and biotin-depleted pigs and chickens. A monoclonal anti-biotin antibody was used as primary antibody in this technique. Immunoreactive biotin was detected in many tissues of both species including liver, kidney, pancreas, adipose tissue, adrenal gland, testis, brain, choroid plexus, cardiac and skeletal muscle, epithelium of the respiratory and digestive systems, skin and lymphoid tissues. The specificity of immunostaining for biotin was confirmed by the finding of reduced staining intensities in tissues of biotin-depleted animals compared to those of biotin-supplemented animals. The results of this study suggest that biotin has metabolic functions in a wider range of tissues than previously known. They also indicate that endogenous tissue biotin should be considered as a source of false-positive staining when immunohistochemical or histochemical techniques which use avidin or streptavidin reagents or anti-biotin antibodies as components of the detection system, are applied to tissue sections.

Animals↗
PubMedDate not supplied

Health barriers to walking for exercise in elderly primary care.

Health status is acknowledged by nursing theory as a factor in the probability of health behavior changes. Yet few studies have addressed the health-related barriers encountered by chronically ill elderly patients in primary care clinics who are trying to increase their physical activity. This study used self- and interviewer-administered instruments to assess potential barriers to physical activity in a sample of 60- to 80-year-old patients entering a walking program. Pain, fatigue, and mobility and sensory impairments were prevalent and could be significant barriers to participation. The authors present specific suggestions for helping patients overcome these barriers.

Activities of Daily Living↗