PubMed Health⌕ Search

Biomedical subjects

J C Edwards

Publications and source records attributed to J C Edwards.

At least 19 recordsLinked to original sources
PubMed1995

Scanning tunnelling microscopy and dynamic contact angle studies of the effects of partial denaturation on immunoassay solid phase antibody.

A range of partial denaturation antibody pre-treatments that affect immunoassay performance have been evaluated. Monoclonal anti-ferritin antibody was either partially denatured by heat, urea or pH pre-treatment or left untreated and then passively adsorbed to polystyrene microtiter wells. The adsorption characteristics and functionality of the different surfaces produced have been evaluated by dynamic contact angle (DCA) analysis and scanning tunnelling microscopy (STM) imaging respectively. The DCA data show that the effect of partial denaturation is to change the wetting characteristics of the antibody surfaces, while, in addition, STM imaging reveals marked effects seen in the aggregation properties of the denatured antibodies.

Adsorption↗
PubMed1995

Avian cathepsin B cDNA: sequence and demonstration that mRNAs of two sizes are produced in cell types producing large quantities of the enzyme.

Overlapping cDNA fragments encoding avian cathepsin B were cloned from an osteoclast cDNA library and sequenced. The primary structure of the prepro enzyme deduced from this sequence has 340 amino acids. The mature portion of the enzyme is 80% identical with murine cathepsin B; regions found in other papain superfamily enzymes are conserved. In osteoclasts and cultured macrophages, which produce large quantities of cathepsin B, mRNAs of 1.8 and 2.4 kb are produced in approximately equal quantities, while cells producing smaller quantities of the enzyme produce predominantly the 2.4 kb form. This variation in mRNAs suggests transcriptional differences related to production of large quantities of the enzyme.

Amino Acid Sequence↗
PubMed1995

Differential distribution of annexins-I, -II, -IV, and -VI in synovium.

OBJECTIVES: To examine the distribution of four annexins in non-inflamed rheumatoid arthritic and osteoarthritic synovial tissue. METHODS: Frozen sections were stained with monoclonal antibodies (MAb) specific for annexins-I, -II, -IV, and -VI, and for cell lineage related markers including CD68 and CD14 (macrophages), prolyl hydroxylase (fibroblasts), and CD3 (T cells). RESULTS: Each of the annexins was present in synovial tissues in significant amounts in the three groups studied. Annexin-I was predominantly found within the synovial lining layer and double labelling showed it to be present predominantly in cells of the macrophage lineage. In rheumatoid specimens there was increased staining within the lining layer, perivascularly and on macrophages within the tissue stroma. Annexin-II was present in a distribution similar to that of annexin-I, but with more prominent perivascular staining. Annexins-IV and -VI were seen chiefly in association with areas of lymphocyte infiltration in rheumatoid tissue, whereas annexins-I and -II were absent from these areas. Endothelial cells stained weakly positive for annexins-I and -II, and more strongly for -IV and -VI. CONCLUSIONS: This study demonstrates that annexins (particularly annexin-I, a putative mediator of the anti-inflammatory activities of glucocorticoids) are abundant in rheumatoid and non-rheumatoid synovial tissue, annexins-IV and -VI having a distribution distinct from that of -I and -II.

Annexin A1↗
PubMed1995

Hepatic function in workers occupationally exposed to carbon tetrachloride.

OBJECTIVES: To identify any differences in hepatic function between workers exposed to carbon tetrachloride and controls, and to identify the best variable with which to examine any effects. METHODS: In a cross sectional study of hepatic function in workers occupationally exposed to carbon tetrachloride, 135 exposed employees were compared with 276 non-exposed controls. The exposed group was taken from three sites in the north west of England and the control group included non-exposed workers from one of these sites and another site located nearby. Demographic and alcohol consumption data were collected from both groups by questionnaire. Each member of the study group was allotted a notional estimated exposure to carbon tetrachloride, calculated from historic personal monitoring data and job category. A fasting sample of blood was taken from all participants and analysed for a variety of biochemical and haematological variables. The techniques of univariate and multivariate analysis of variance were used to investigate the effect on biochemical and haematological indices of a range of factors. RESULTS: Multivariate analysis of variance of four core liver function variables, alanine transaminase, aspartate transaminase, alkaline phosphatase, and gamma-glutamyl transferase, showed a significant difference between exposed and non-exposed workers. The univariate analyses identified increases in only alkaline phosphatase and gamma-glutamyl transferase within the exposed group and these did not show a significant dose-response relation. Univariate analysis of variance did show effects of alcohol and age on several variables. Significant differences between exposed and control groups for three haematological variables, haemoglobin, packed cell volume, and red blood count, were thought not to be due to the effects of exposure. Clinical review of exposed subjects with abnormal results did not show clinically evident disease that could have been associated with exposure to carbon tetrachloride. Also, a follow up study conducted three years after the cross sectional study at the site with highest exposures to carbon tetrachloride showed no evidence of any further changes in liver function variables. CONCLUSIONS: The most sensitive statistical methods have shown significant differences in the liver function variables measured between people exposed to carbon tetrachloride and the control group. The interpretation of the data collected was that these differences may be due to exposure to carbon tetrachloride but this was not clearly shown. Furthermore, the changes found have not given rise to any clinical disease.

Adult↗
PubMed1995

Alterations in hyaluronan synthesis during developing joint cavitation.

The mechanisms essential for generating diarthrodial joint cavities between skeletal elements in developing limbs remain enigmatic. Histochemical localization of hyaluronan (HA) at joint interzones concomitant with cavitation led to the postulation that HA may be pivotal in this process. HA synthesis involves the transfer of UDP-glucuronate and UDP-N-acetyl glucosamine to nascent HA by HA synthase. Uridine diphosphoglucose dehydrogenase (UDPGD) activity is responsible for the prior conversion of UDP-glucose to UDP-glucuronate. We have assessed the relationship between the appearance of HA and enzyme activities (quantitatively where possible) involved in HA synthesis during metatarsophalangeal joint development in embryonic chicks. Microspectrophotometric assessment of UDPGD activity using an in situ biochemical assay indicated that cells immediately adjacent to forming cavities contained increased UDPGD activity, which was subsequently maintained after cavitation. Immunocytochemistry showed that high levels of expression of HA synthase were localized to these same cells. In addition, radiolabeled sulfate autoradiography showed that cells bordering developing cavities incorporated relatively little sulfate, suggesting that UDP-glucuronate is utilized in the synthesis of undersulfated or non-sulfated glycosaminoglycans. These results indicate that the differentiation of cells bordering presumptive spaces may involve alterations associated specifically with differential synthesis of HA, which appears to be a primary event in joint cavity formation.

Animals↗
PubMed1995

Samarium-153-particulate hydroxyapatite radiation synovectomy: biodistribution data for chronic knee synovitis.

UNLABELLED: Biodistribution data for the radiation synovectomy agent samarium-153-particulate hydroxyapatite (153Sm-PHYP) are reported. METHODS: Mean extra-articular activity accumulation calculated from serial whole-body scans in 13 patients treated for chronic knee synovitis was 0.74% of injected activity (range 0%-3%). RESULTS: In four patients (31%), activity was noted in the lung (mean 0.68% of injected activity). In six patients (46%), 0.29% of injected activity accumulated in the regional lymph nodes and in three patients (23%), 0.62% of injected dose accumulated in the liver. Absorbed dose estimates were lung: 14 mGy, regional lymph nodes; 50 mGy, liver; 4 mGy. SPECT demonstrated good distribution of 153Sm-PHYP throughout the anterior knee compartments, although distribution to the posterior compartment was variable. CONCLUSION: Distribution is dependent on adequate knee flexion immediately following injection and may be influenced by the size range of labeled particles. Favorable biodistribution data suggest that 153Sm-PHYP is a potentially useful radiation synovectomy agent.

Adult↗
PubMed1994

An induced extracellular matrix protein reverses the polarity of band 3 in intercalated epithelial cells.

The intercalated epithelial cell exists in two interconvertible forms in vivo, one where band 3 protein is apical and the other where it is basolateral. We seeded an immortalized clone of these cells at low density and found that band 3 was apical at confluence. There was little or no apical endocytosis. But when the cells were plated at high density, band 3 was basolateral, and there was vigorous apical endocytosis. Extracellular matrix produced by high density cells was able to retarget band 3 in low density cells and to induce apical endocytosis, as did a 230 kd protein partially purified from this matrix. Therefore, polarized targeting of some proteins is determined by external cues that might determine their polarity by reorganizing the cytoplasm.

Animals↗
PubMed1994

A scanning tunnelling microscopy comparison of passive antibody adsorption and biotinylated antibody linkage to streptavidin on microtiter wells.

An antiferritin antibody was either, (a) passively adsorbed to microwells or (b) biotinylated and immobilised to streptavidin coated microwells. Scanning tunnelling microscope (STM) imaging of these well surfaces coated with a platinum (95%) carbon (5%) coating (Pt/C) conductive layer showed a randomly oriented array of antibodies for passive adsorption whereas for biotin-streptavidin immobilisation there was a more uniform and even distribution of antibodies on the well surface. On further incubation with ferritin STM imaging showed that for passive adsorption approximately 5% of the surface was functional, while for the biotinylated antibody it was greater than 60%. The images presented in this paper show graphically the loss of functionality that occurs using passive adsorption and, conversely, the preservation of antibody functionality using the biotin-streptavidin linkage for antibody immobilisation. These results correlate well with the work of others in the field.

Adsorption↗
PubMed1994

Circulating and synovial fluid hyaluronan levels. Effects of intraarticular corticosteroid on the concentration and the rate of turnover.

OBJECTIVE: To assess the effect of intraarticular (IA) corticosteroid on hyaluronan (HA) concentrations in synovial fluid (SF) and serum and the clearance of 131I-labeled albumin from the joints of patients with rheumatoid arthritis (RA), osteoarthritis (OA), and ankylosing spondylitis (AS). METHODS: SF and serum were collected before and 2 weeks and 2 months after IA steroid injection. The HA concentration was assessed using an enzyme-linked immunosorbent assay and 131I-albumin clearance from joints was assessed using an external gamma counter. RESULTS: In RA patients, HA concentrations in the SF were increased following IA steroids, while the serum concentrations were decreased. In OA patients, HA concentrations in SF tended to increase initially (decreasing thereafter), and were associated with increased HA concentrations in serum. There were less marked alterations in the AS patients. Albumin clearance rates were decreased significantly (2 weeks postinjection) only in the RA patients. Estimated HA flux revealed discrepancies between the HA concentration and the rate of flux in RA and AS patients. CONCLUSIONS: These findings suggest that IA steroid injection is associated with a restoration in the relationship between SF and serum HA concentrations toward normal levels.

Adrenal Cortex Hormones↗
PubMed1994

Positioning of the posterior cruciate ligament.

The isometric position in ligament reconstruction is the one in which there is little or no change in the length of the graft with range of motion of the joint. It varies according to the positions of the tunnels that will become the attachment sites of whatever graft is being used. Better understanding of this concept that greatly improved the surgical results of intra-articular reconstructions of the anterior cruciate ligament. Unfortunately, the results of posterior cruciate ligament (PCL) reconstructions have lagged behind. A better understanding of the isometry of the PCL and how it relates to the positioning of a graft at the time of reconstruction should help improve the situation. The current scientific studies on the PCL as they relate to isometry are evaluated and summarised in this paper. The tibial isometric point was universally less sensitive to changes in position than was the femoral isometric point. However, all the points that were evaluated for the tibia fell within the normal insertion area of the PCL. This has important ramifications when extrapolating these laboratory studies to the operating room, where it is imperative to get the tibial tunnel or attachment site distal enough on the tibia so that it will be in the usual anatomic location of the PCL. There is less uniformity when it comes to the femoral isometric point, but once again the isometric point from each of the studies fell within the normal anatomic femoral attachment site. The differences between the selected points may be explained by the different study designs.

Cadaver↗
PubMed1994

Hyaluronan concentration in non-inflamed and rheumatoid synovium.

The concentration of hyaluronan was measured by a novel application of an ELISA technique, using biotinylated hyaluronan binding-region (HABr) derived from cartilage proteoglycan core-protein, to digested frozen sections of synovium. The relative extractability of hyaluronan, from sections of synovium by short-term washes in buffer, was assessed by the same method. The distribution of hyaluronan in adjacent sections was assessed histochemically using the biotinylated HABr and alkaline phosphatase-conjugated streptavidin. Hyaluronan concentrations were lower in rheumatoid synovium (0.71 +/- 0.10 mg/cm3; mean +/- S.E.M.) than in non-inflamed synovium (1.07 +/- 0.16 mg/cm3). However, the ratio of extractable or 'free' hyaluronan to non-extractable or 'bound' hyaluronan, was greatly increased in rheumatoid synovium, being 4.53 +/- 0.40 (mean +/- S.E.M.) compared with 1.87 +/- 0.42 in non-inflamed synovium. Histochemical staining showed hyaluronan to be concentrated in the lining layer of non-inflamed samples, whereas in rheumatoid synovium the stain was more uniformly distributed throughout the tissue. Although the total concentration of hyaluronan was not increased in rheumatoid synovium, the increased proportion of 'free', and therefore presumably mobile, hyaluronan molecules together with increased synovial bulk may contribute to the known increases in serum levels of hyaluronan in patients with RA.

Adolescent↗
PubMed1994

Zonal distribution of chondroitin-4-sulphate/dermatan sulphate and chondroitin-6-sulphate in normal and diseased human synovium.

OBJECTIVES: Chondroitin sulphate is the major sulphated glycosaminoglycan present in the extracellular matrix of soft connective tissues and the aim of this study was to investigate the distribution of chondroitin sulphate species in normal and diseased synovium. METHODS: Distribution of chondroitin-4-sulphate/dermatan sulphate (Ch4S/DS) and chondroitin-6-sulphate in normal (n = 6), osteoarthritic (n = 4) and rheumatoid (n = 10) synovium was determined using an immunoperoxidase technique and specific monoclonal antibodies to chondroitinase ABC-digested preparations. RESULTS: Ch4S/DS was expressed throughout the interstitium of all tissues and was also present on blood vessels in rheumatoid samples only. Ch6S was expressed in the lining layer of normal synovium but was absent from this site in osteoarthritic and rheumatoid tissues. Ch6S was also present on all blood vessels in all tissues. CONCLUSIONS: The distinct zonal distributions of Ch4S/DS and Ch6S and their alteration in disease suggest these molecules have different and specific functions in normal and diseased synovium.

Arthritis, Rheumatoid↗
PubMed1994

Expression of CD44 in normal and rheumatoid synovium and cultured synovial fibroblasts.

OBJECTIVE: To determine if expression of CD44, the principal receptor for hyaluronan, was altered in rheumatoid (RA) synovium and cultured rheumatoid synovial fibroblasts. METHODS: Synovium was obtained from normal adult human joints (n = 4) and from joints of patients with RA (n = 5). Specific monoclonal antibodies to CD44 were used in immunofluorescence of whole synovium and cultured synovial fibroblasts and in quantitative Western blotting and ELISA of CD44 in cultured synovial fibroblasts. RESULTS: CD44 was restricted to the lining layer in normal synovium but present, in reduced concentrations, throughout rheumatoid synovium. Cultured rheumatoid cells were 19% larger in area and showed far fewer and less extensive CD44-positive cytoplasmic extensions, together with reduced staining intensity compared with normal. Quantitative Western blotting normalised for cell protein showed a 75% reduction (normal = 1754 (835), rheumatoid = 409 (84) mean (SD) arbitrary units) in the amount of CD44 in rheumatoid cells compared with normal, and enzyme linked immunosorbent assay (ELISA) of cultured cell monolayers normalised for cell number indicated a 29% reduction (normal = 0.707 (0.110), rheumatoid = 0.504 (0.103), mean (SD) optical density at 405 nm). CONCLUSIONS: Rheumatoid synovial cells showed altered morphology and reduced CD44 expression compared with normal cells. CD44, by means of modulated associations with the cytoskeleton, may be involved in cell shape change.

Aged↗