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Biomedical subjects

P Chu

Publications and source records attributed to P Chu.

At least 91 records · Page 5Linked to original sources
PubMed1990

Generation and characterization of monoclonal antibodies specific for the retinal pigment epithelium.

Although both the neural retina and the retinal pigment epithelium (RPE) arise as neighboring portions of the embryonic optic cup, these two tissues follow very different developmental pathways. In order to obtain probes for the analysis of RPE development from its earliest divergence from the neural retina to late stages of differentiation, we have developed a panel of monoclonal antibodies which recognize antigens specific to the RPE. These probes have been applied to an immunohistochemical analysis of RPE development. The results indicate that the RPE is antigenically distinct from the neural retina even before the onset of overt differentiation. In addition, the RPE layer of the retina becomes further subdivided antigenically as its distinct anterior and posterior derivatives develop. These antibodies will be useful markers in the analysis of RPE development.

Animals↗
PubMed1989

Defective fibrinolysis in Behçet's syndrome: significance and possible mechanisms.

Reduced fibrinolytic activity has frequently been reported in Behcet's syndrome, but both the underlying mechanism and its relation to the development of thrombosis are unclear. The fibrinolytic activity was studied in seven patients with Behçet's syndrome and 12 patients with idiopathic oral ulceration. The patients with Behçet's disease had significantly reduced resting tissue plasminogen activator(t-PA) both by euglobulin fibrin plate lysis and enzyme linked immunosorbent assay (ELISA), but the tissue plasminogen activator inhibitor(t-PAI) was not significantly different from the control value. After stimulation by venous occlusion the euglobulin fibrin plate lysis results showed three good responders and four poor responders, but neither t-PA antigen nor t-PAI concentrations showed any clear difference between the two groups. Interestingly, three out of the four patients with a history of thrombosis were good responders. The group with oral ulceration showed no significant difference from the controls for any of these measurements. These findings suggest that the reduced resting fibrinolytic activity is usually due to decreased production of t-PA, but that the defective response to stimulation may be multifactorial in origin. The fibrinolytic abnormalities appear unrelated to the development of thrombosis.

Adult↗
PubMed1988

Plasma lipid and lipoprotein response to carbohydrate feeding in cirrhotic patients.

Serum lipids and lipoproteins, and glucose and insulin, were measured after an overnight fast, and during 3 days of a eucaloric diet rich in carbohydrate, in 15 patients with cirrhosis and seven normal subjects. Following the high-carbohydrate diet triglyceride rose in all groups but the increase in cirrhotics was lower than in normals. In normals and in cirrhotics with good liver function most of the triglyceride increment was carried in VLDL; in cirrhotics with poor liver function only 31% of the increment was found in VLDL, and 56% in triglyceride-rich LDL. In an earlier study on fat feeding, our cirrhotic patients with poor liver function had an impaired chylomicron and VLDL response; they also carried most of the triglyceride increment in triglyceride-rich LDL. The markedly impaired response of triglyceride-rich lipoproteins to both carbohydrate and fat feeding suggests that sick cirrhotics may have a problem with storage of dietary energy and that this contributes to loss of their adipose tissue.

Adult↗
PubMed1988

Abnormal fibrinolytic activity in systemic lupus erythematosus and possible mechanisms.

Plasma fibrinolytic activity was measured in 34 patients with systemic lupus erythematosus (SLE) and 12 normal subjects. Patients with SLE showed a significantly reduced resting level of plasma tissue plasminogen activator (t-PA) compared to normal. The reduction in t-PA was demonstrated both by a functional assay (fibrin-plate lysis, FP) and an immunochemical assay (ELISA). Measurement of the fibrinolytic response following venous occlusion allowed division of the patients into two groups. In the first (24 patients), there was a normal increase in t-PA response, demonstrated both by the functional and immunochemical assays. In the second (10 patients), there was a significantly reduced plasma t-PA response measured by FP. Seven of the patients in this second group, which included four patients with histological evidence of vasculitis, showed a similar failure of t-PA response (ELISA) after venous occlusion. These results suggest that their impaired fibrinolytic response may be related to defective t-PA release secondary to endothelial cell damage. The remaining three patients in the latter group had a normal t-PA (ELISA) response despite a reduced FP response, suggesting the presence of an inhibitor.

Adult↗
PubMed1987

Myelodysplasia presenting as erythroderma.

Erythroderma has not previously been reported to be a feature of myelodysplasia. We report two cases of myelodysplasia presenting with erythroderma, one of which was associated with skin infiltration by blast cells.

Aged↗
PubMed1986

DIDMOAD syndrome with megacystis and megaureter.

A case of DIDMOAD syndrome (diabetes insipidus, diabetes mellitus, optic atrophy and nerve deafness) is described. There was unusually severe urinary tract dilatation which led to an ileal conduit diversion. Immunohistological study of the bladder wall and ureter revealed a marked diminution in nerve fibres, which may have been primary or secondary to the muscle hypertrophy. The possible pathogenesis of the urinary tract dilatation is discussed in relation to this finding.

Adult↗
PubMed1985

Red cell metabolism in renal failure--the effect of dialysis.

The mechanism of the increased haemoglobin (Hb) and erythrocyte survival in continuous ambulatory peritoneal dialysis (CAPD) compared to haemodialysis (HD) was investigated by measuring hexose monophosphate shunt (HMP) activity and reduced glutathione concentration (GSH) in 12 patients--six patients who were stable on CAPD, and six patients who were stable on HD, and also six normal controls. We confirmed the rise in haemoglobin in the CAPD group. The HMP activity, measured by the liberation of 14CO2 from radioactive glucose labelled at the C1 position shows that both HD and CAPD groups fall into the normal range (normal 3-11%) although the HMP activity is higher in the HD group. The reduced glutathione concentration in the three groups was: normal controls 2.41 +/- 0.19 mmol/l; HD 3.31 +/- 0.43 mmol/l; CAPD 2.68 +/- 0.24 mmol/l. The HD group is significantly higher (P less than 0.01) than both normal and CAPD. We conclude that the rise in haemoglobin in CAPD patients is not related to a more effective HMP. This suggests other mechanisms i.e. marrow function or red-cell loss in HD may be the reason for the lower haemoglobin in this group.

Cell Count↗
PubMed1977

Rubidium-82 generators for imaging studies.

Strontium-82, produced by spallation reaction with medium-energy proton beams, was used to evaluate Bio-Rex 70 and Chelex-100 ion-exchange resins for use in a compact Rb-82 generator. Adsorption of Sr-82 to the resin column, Rb-82 elution yields, Sr breakthrough, and 82Rb-Sr separation factors were determined for newly prepared columns and for longterm elution conditions. Separation factors of 10(7) to 10(8) were obtained with 2% NaCl elutions from Bio-Rex 70 resin columns while the separation factors was about 5 X 10(4) with the Chelex-100 resin column.

Evaluation Studies as Topic↗
PubMed1976

Assay of an activator for lipoprotein lipase.

A method is described which enables the ability of human serum to activate guinea pig lipoprotein lipase to be measured in terms of an arbitrary standard. Evidence is offered which strongly suggests that the substance measured is also the activator of human lipoprotein lipase and observations on the relative levels of activator in human sera are given.

Animals↗