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Biomedical subjects

J Kelly

Publications and source records attributed to J Kelly.

At least 361 records · Page 20Linked to original sources

Competition studies with repressors and activators of viral enhancer function in F9 mouse embryonal carcinoma cells.

DNA competition studies have been used to investigate the presence of a repressor of viral enhancer function in F9 mouse embryonal carcinoma cells. The complete polyoma virus enhancer region, cotransfected into F9 cells with the SV40 promoter/enhancer attached to a chloramphenicol acetyl transferase marker gene, induced a small increase in pSV2CAT expression. This can be explained by preferential but weak binding by polyoma sequences of a molecule repressing pSV2CAT transcription. Repressor activity substantially disappeared when the cells were induced to differentiate by retinoic acid. Repressor binding was localised to one half of the polyoma enhancer, but was lost on further fragmentation of this region. It appears that multiple sequence elements may be required for repressor binding and that these are at least partially separable from the complement of elements binding enhancer activating molecules.

Animals↗

Removal of endogenous peroxidase activity from cryostat sections for immunoperoxidase visualisation of monoclonal antibodies.

The interpretation of immunoperoxidase staining of frozen tissue sections can be severely limited by the presence of endogenous peroxidase enzymes in the tissue. Previously recommended methods of reducing this enzyme activity were examined, but were found to be unsatisfactory when applied to the small intestine. A method, which effectively eliminates this background staining but which does not interfere with the binding of monoclonal antibodies to various tissue components, is described. This method may prove useful in immunoperoxidase studies of other tissues in which high levels of endogenous peroxidase are present.

Antibodies, Monoclonal↗

Humoral response to alpha gliadin as serological screening test for coeliac disease.

The diagnostic value of measuring alpha gliadin antibodies in children with suspected coeliac disease has been evaluated prospectively. Jejunal biopsy and alpha gliadin antibody measurements were performed in 77 consecutive children who were being investigated for a suspected malabsorption syndrome. The typical small intestinal histological lesion of coeliac disease was found, and this diagnosis was subsequently confirmed clinically in 20 children. Raised IgG alpha gliadin antibody concentrations were found in 19 (95%). Fifty of 57 patients (88%) with a normal jejunal mucosa had normal alpha gliadin antibody concentrations. These results are similar to those previously reported in a prospective study of adult patients with coeliac disease and indicate that measurement of alpha gliadin antibody is a highly sensitive and specific screening test for childhood coeliac disease.

Adolescent↗

Beta-adrenoceptor adaptation to endurance training.

Endurance exercise is associated with various cardiovascular adaptations, and these may include changes in sympathoadrenal activity and end-organ responsiveness to norepinephrine (NE). Because beta-adrenoceptor function is a major determinant of sympathetic responsiveness, we used the lymphocyte beta-adrenoceptor as a model to study the effects of endurance training in 19 male subjects before, during, and after preparation for a marathon race. Before the subjects trained, resting beta-adrenoceptor density was positively correlated to resting heart rate (r = 0.47, p less than 0.05) but this correlation was not evident after training. Eleven of the 19 subjects completed the 3 1/2-month training period, and mean (+/- 1 SD) resting beta-adrenoceptor density fell from 1,593 +/- 333 to 1,197 +/- 332 sites per cell (p less than 0.02) after the training period. Two weeks after cessation of training, receptor density was at pretraining values of 1,547 +/- 209 sites per cell. During training, the subjects ran two 21-km races. Each of these was associated with decreases in beta-adrenoceptor density. Our results demonstrate the episodes of endurance running result in reductions in lymphocyte beta-adrenoceptor density. We conclude that down-regulation of beta-adrenoceptors is an important component of the response to endurance training.

Adult↗

Immunoperoxidase demonstration of the cellular composition of the normal and coeliac small bowel.

Immunohistological analysis of the cellular composition of the small intestinal mucosa in a group of untreated and treated coeliac patients and non-coeliac control subjects was performed using monoclonal antibodies and an immunoperoxidase technique. A characteristic cellular distribution was observed within the normal mucosa. The intraepithelial and lamina propria compartments were occupied mainly by T suppressor/cytotoxic and T helper/inducer cells respectively. Further subdivision of lamina propria T helper/inducer cells with the Leu 8 antibody revealed that these were of the Leu 3a+ Leu 8- phenotype. Macrophages, defined by the RFD7 antibody, were seen to occupy the same microenvironment as T helper/inducer cells. T cells expressing the T cell activation antigen defined by anti-Ta1 were found with the normal lamina propria, although few cells were identified by the anti-Tac antibody. HLA-Dr antigens were expressed by stellate cells within the lamina propria, and also by the epithelial cells of the villi, but not by normal crypt epithelial cells. In untreated coeliac patients the distribution of the various cell types was essentially unchanged, although the number of these cells was markedly increased, including those which expressed the Ta1 antigen. A significant deviation from normal in the expression of HLA-DR antigens was found in the coeliac small bowel: these antigens were expressed not only on the villous epithelial cells but also on the epithelial cells of the crypts. Immunohistological findings in the treated coeliac patients were intermediate between the normal and untreated coeliac groups, and were completely normal in those patients with complete histological resolution of their disease. These results suggest that coeliac disease is accompanied by an enhanced stimulation of the normal mucosal immune response and do not imply a primary pathogenic role for the immune system in this disease.

Antigens, Surface↗

Flow-cytometric detection of circulating immune complexes.

In an effort to develop an assay which would rapidly detect and analyze circulating immune complexes, we have adapted the Raji cell radioimmunoassay (RIA) to a flow cytometric (FCM) analysis. The advantages of immune complex analysis by FCM are many. Foremost is the effectiveness and efficiency of the FCM method relative to the radioimmunoassay (RIA) method. The data demonstrated that FCM detection is three times more sensitive than RIA detection. Only populations of viable Raji cells bearing immune complexes are analyzed because parameters of the FCM analysis permitted the elimination (gating out) of dead cells. The determinations are rapid and the data are immediately available for several additional analyses. Because of the availability of many fluorescent monoclonal antibodies to complement components, viral antigens, light chains and immunoglobulin isotypes, it is possible to detect many components that might be present in the Raji cell bound complexes. Finally, the Raji cells can be characterized in different stages of their cell cycle to generate information about the state of the cells and the density of the receptors involved in binding the complexes.

Antigen-Antibody Complex↗

Susceptibility of normal human lymphocytes to infection with HTLV-III/LAV.

Normal human peripheral blood lymphocytes were tested for their susceptibility to infection with retroviruses isolated from patients with the acquired immunodeficiency syndrome (AIDS) or AIDS-related complex. Of 10 normal individuals tested, lymphocytes from all subjects became infected and produced virus as detected by assay for Mg+2-dependent reverse transcriptase. Lymphocytes from different individuals were demonstrated to be either high or low producers of reverse transcriptase after infection. The kinetics of virus production were similar in cells from both high- and low-producing individuals. A significant correlation was observed between high and low viral-producing lymphocytes and expression of the Leu-3/T4 (CD4) surface molecule. Mitogen-stimulated peripheral blood lymphocytes exposed to HTLV-III/LAV manifested productive viral infection, as reflected by the appearance of early syncytia, followed by reverse transcriptase. Unstimulated peripheral blood lymphocyte cultures displayed late syncytia but no detectable reverse transcriptase upon exposure to virus. The addition of anti-human interferon-alpha did not appear to have an appreciable effect on viral production in normal peripheral blood lymphocytes exposed to the virus.

Acquired Immunodeficiency Syndrome↗

Neuropsychologic features of early- and late-onset Alzheimer's disease.

Forty-one patients with clinically diagnosed Alzheimer's disease were divided into two groups for comparison of neuropsychologic features in those with early- and late-onset disease. Handedness was also assessed in all patients. Twenty-three patients with onset before age 65 had significantly more language impairment, whereas 18 patients with onset at age 65 or older had more difficulty with visuoconstructional function. Memory was severely impaired in all patients. Only one patient in each group was left-handed, and the same results were obtained when these were excluded. These observations support the notion of left hemisphere vulnerability in early-onset Alzheimer's disease and can be interpreted as demonstrating the clinical variability of the illness rather than the necessity of dividing it into two distinct entities.

Age Factors↗

Type II collagen of lamprey.

The major collagen in lamprey notochord is type II, as determined by its amino acid composition and solubility properties. This collagen has a distribution of charged residues indistinguishable from higher vertebrate Type II collagens as judged by its SLS banding pattern. Lamprey type II collagen has a higher thermal stability than lamprey skin collagen, in contrast to the identical melting temperatures for these types in mammals. A minor collagen in lamprey notochord has solubility properties, amino acid composition, and electrophoretic mobility similar to that of 1 alpha, 2 alpha, 3 alpha collagen in human cartilage.

Amino Acids↗

Pharmacokinetic studies of imipenem/cilastatin in elderly patients.

Six patients, aged between 68 and 83 years, with glomerular filtration rates (GFR) between 31 and 80 ml/min received imipenem/cilastatin as treatment for acute lower respiratory tract infection. A combination of 500 mg of both agents was administered, 6-hourly, intravenously over 30 min. After a minimum of four doses, blood specimens were obtained for assay of imipenem and cilastatin concentrations by HPLC. Pharmacokinetic parameters were calculated from the results. The mean half life was 1.6 h for imipenem and 2.1 h for cilastatin, values similar to those reported for patients with moderate renal impairment. Elimination constant, clearance and AUC significantly correlated with GFR but not with age. No accumulation was observed.

Age Factors↗

Ground squirrel hepatitis virus (GSHV) infection and hepatocellular carcinoma in the Canadian Richardson ground squirrel (Spermophilus richardsonii).

Sera and livers from 40 Richardson ground squirrels were examined for evidence of ground squirrel hepatitis virus (GSHV) infection and hepatocellular carcinoma. Twenty-five sera were obtained from fully grown adult ground squirrels and 15 from young ground squirrels estimated to be between 6-8 weeks of age. All animals had been caught in the wild and had spent less than 1 month in captivity. Sixteen sera (40%) had at least one serologic marker of GSHV (2 with GSHV surface antigen, 3 GSHV core antigen, 5 GSHV antibody to core antigen and 11 GSHV antibody to surface antigen). Two cases of hepatocellular carcinoma were detected, both in adult ground squirrels. Tumour tissue and adjacent normal liver tissue were negative for GSHV surface and core antigen by direct immunofluorescence in both livers and negative for GSHV-DNA by molecular hybridization in the one tumour examined. These results indicate that: A) GSHV is geographically more widespread than previously considered; B) viral transmission occurs early in life, probably via the vertical route; and C) hepatocellular carcinoma is a relatively common finding in these animals while still in their wild state. Any causal relationship between hepatocellular carcinoma and GSHV infection in these animals, however, has yet to be demonstrated.

Animals↗

Clinical, morphological, and biochemical alterations in acute intestinal Yersiniosis.

The aim of this study was to examine the intestinal response to Yersinia enterocolitica (YE) infection. Growing New Zealand white rabbits (450-800 g) were infected with 10(10) organisms of a human pathogenic strain (n = 43) or NaHCO3 for controls (n = 30) and studied 3, 6, 10, and 14 days after infection. In a separate experiment infected (n = 6) and pair-fed controls (n = 6) were studied 6 days after infection. Weight gain, excretion of YE, and diarrhea were examined daily. At sacrifice segments of proximal and mid- and distal small intestine, cecum, and colon were obtained for histologic examination and mucosa of small intestine and colon for enzyme determinations. Infection with YE resulted in weight loss and diarrhea within 48-72 h. Microabscesses were present in all sections of small and large intestine by day 3 but became more severe in the ileocecal region by day 6. In infected animals at day 6 there was crypt hyperplasia throughout the small intestine and villus atrophy in the ileum. Disaccharidases were decreased in all regions by day 3 but returned to normal by day 14 in proximal and mid-, but not distal, small intestine. The pair-fed controls experienced a similar weight loss to infected animals, but showed only minor morphologic changes and no mucosal enzyme abnormalities. Our findings demonstrate that infection of weanling rabbits with YE causes diarrhea and weight loss and that, while the weight loss is largely due to reduced food intake, the morphologic and mucosal enzyme alterations are due to intestinal injury by the organism.

Acute Disease↗