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Biomedical subjects

V Chan

Publications and source records attributed to V Chan.

At least 163 records · Page 9Linked to original sources
PubMed1985

Risk factors influencing survival in acute renal failure treated by hemodialysis.

A retrospective analysis of 58 patients with acute renal failure treated by hemodialysis between 1980 and 1984 was carried out to study mortality and the risk factors that might adversely influence survival. Twenty-six factors, suggested by published data to be relevant to the short-term prognosis of such patients, were evaluated by univariate analysis. Survivors were found to be significantly younger, they were less frequently malnourished or jaundiced, and fewer required inotropic drugs (due to hypotension) or ventilator support after the first week of their illness. Sepsis, heart failure, central nervous system depression, and a greater number of the above complications were characteristic in the nonsurvivors. Multivariate analysis suggests that the probability of survival could be estimated by taking into account three of these factors: age, central nervous system depression, and hypotension. Further studies would be appropriate to test the predictive value of such a probability equation.

Acute Kidney Injury↗
PubMed1984

BamH I polymorphism in the Chinese: its potential usefulness in prenatal diagnosis of beta thalassaemia.

The prevalence of the BamH I site 3' to the beta globin gene in Chinese people was determined in 123 normal subjects, 40 patients with heterozygous beta thalassaemia, and 25 patients with homozygous beta thalassaemia. The site was present in 71.1% and absent in 28.9% of the chromosomes carrying normal beta genes. All 25 patients with beta thalassaemia major had the site. This BamH I polymorphism may be used for prenatal diagnosis in about 29% of the pregnancies at risk.

Adult↗
PubMed1984

Hypofibrinogenemia due to increased fibrinolysis in two patients with acute promyelocytic leukemia.

Two patients with acute promyelocytic leukemia and severe bleeding associated with hypofibrinogenemia were studied. The markedly shortened whole blood clot lysis time and dilute clot lysis time suggested that the defect was an increase in fibrinolysis. Although disseminated intravascular coagulation could not be totally excluded as an alternative mechanism, excessive fibrinolysis was confirmed as the pathogenic cause by the prompt response to the administration of tranexamic acid. The low circulating plasminogen, alpha 2 plasmin inhibitor level and the presence of alpha 2 plasmin inhibitor-protease complex in both patients suggested that the increased fibrinolysis probably resulted from the liberation of plasminogen activator from the promyelocyte.

Adult↗
PubMed1984

Diffuse proliferative lupus glomerulonephritis. Determination of prognostic significance of clinical, laboratory and pathologic factors.

Clinical, laboratory and pathological factors in 35 females with diffuse proliferative lupus glomerulonephritis were analyzed to determine the prognostic significance of the individual variables. The clinical and laboratory variables were age, serum creatinine (Cr), serum C3, serum C4 and proteinuria at the time of biopsy while the biopsy ones included intraglomerular monocytic infiltration (NSE index), total glomerular deposits, extent of subendothelial deposits, extent of extraglomerular deposits, tubulo-interstitial inflammation, relative tubulo-interstitial volume and total pathologic score. Standard morphometric and counting procedures were used to determine the levels of all pathologic variables but pathologic score and extra glomerular deposits where grading estimates were done. Survival curves were determined by the life table method. Logrank and chi-square tests were used to establish levels of statistical significance. Seven patients developed established renal failure (Cr greater than or equal to 2.0 on two or more occasions at least 3 months apart) and nine showed significant deterioration of renal function (decrease in CrCl of 25% or more in between biopsy and last follow-up visit or an increase in serum Cr of 0.4 mg/dl or more over the follow-up period). The 5-year renal survival rate (absence of established renal failure) for the whole group was 77%. Serum Cr (p less than .005) and extent of extraglomerular deposits (p less than .025) were shown to be significant prognostic factors for renal survival. Of the seven patients who developed renal failure none had an NSE index greater than 3.0 and one had a C3 greater than or equal to 45 mg/dl. Statistically these factors were weak prognostic indicators (0.5 less than p less than .1). Multivariate analysis demonstrated that the extraglomerular deposit factor contributed significant additional prognostic information to that provided by Cr. Although not important as a prognostic factor on its own, the NSE index significantly improved the prognostic performance of serum Cr. The product of the NSE index and serum C3 proved to be a strong prognostic factor (p less than .005).

Adolescent↗
PubMed1983

Cell-free synthesis of factor VIII related protein.

Polyadenylated ribonucleic acid (RNA) was isolated from confluent human endothelial cells in culture and translated in a cell-free rabbit reticulocyte lysate protein-synthesizing system. Using specific immunoprecipitation, the translation product was found to contain 1.58% VIII related protein (VIII R), which has a molecular weight of 0.26 X 10(6), similar to the subunit of VIII R present in normal plasma. This indicated that VIII R messenger RNA is responsible for the synthesis of subunits only and intracellular post-translational events are required for the assembly of tetramer and multimers.

Antigens↗
PubMed1982

The effect of oral contraceptives on coagulation and fibrinolytic parameters in the Chinese--a prospective study.

Thirty-two Chinese and 7 Caucasians were studied prospectively for 12 months for the effects of oral contraceptives (OC) on certain coagulation and fibrinolytic parameters. In both ethnic groups there was an increase in alpha 1 antitrypsin level. There was no significant change in antithrombin III concentration measured either by radioimmunoassay (At-III-RIA) or chromogenic assay (anti Xa-chromogenic) in the Chinese, but a significant decrease in anti Xa-chromogenic at 7 months and At-III-RIA at 12 months in the Caucasians. Also, alpha 2 plasmin inhibitor (alpha 2 PI) levels were unchanged in the Chinese but a significant increase occurred in the Caucasians at 12 months. Enhanced fibrinolytic response to venous occlusion was demonstrated in the Chinese at 12 months but not in the Caucasians.

Adult↗
PubMed1982

Characterization of factor VIII related protein synthesized by human endothelial cell: a study of structure and function.

Crossed immunoelectrophoresis showed that factor VIII related protein (VIII R) synthesized in the human endothelial cell (EC-VIII R) had faster electrophoretic mobility than that secreted into the culture medium (MED-VIII R). Sodium dodecyl sulphate agarose gel electrophoresis followed by radioimmunofixation showed that EC-VIII R consisted of molecules varying from 0.26 x 10(6) to 3.76 x 10(6) daltons while MED-VIII R had molecules ranging from 0.93 x 10(6) to greater than 10 x (10)6 daltons, similar to that present in plasma. The smallest VIII R molecule present in normal plasma or spent culture medium (0.93 x 10(6) daltons) corresponded to a tetramer of subunits of 0.22-0.24 x 10(6) daltons. Only molecular forms greater than 3.76 x 10(6) daltons possessed ristocetin cofactor activity. Sonication (15 mu amplitude for 30 secs) effectively broke the non-covalent bonds of the VIII R multimers resulting in smaller molecules. Thus endothelial cells in culture synthesized VIII R subunits and assembled them into the higher multimeric forms on secretion. Different types of von Willebrand disease could result from defects of either of the two processes.

Antigens↗
PubMed1982

[Effects of gliclazide and glibenclamide on platelet function, fibrinolysis and metabolic control in diabetic patients with retinopathy (author's transl)].

In order to compare the metabolic and hemobiological properties of two sulfonylureas, thirty-five non-insulin-dependent diabetics were randomly assigned to two groups. Each group was given either gliclazide (n = 20) or glibenclamide (n = 15) for six months. Metabolic control was improved in both groups, as evidenced by the decrease in HbA1 concentrations. A significant fall in ADP (1 and 4 microM)--induced platelet aggregation was recorded in the gliclazide group, while antithrombin III levels remained normal throughout the trial and plasminogen activator levels increased. These hemobiologic changes may be effective in preventing the vascular complications of diabetes. In contrast, glibenclamide did not alter platelet aggregation. Furthermore, a significant decrease in both antithrombin III levels and basal and venostasis-stimulated plasminogen activator levels were seen in glibenclamide patients. The beneficial changes in hemostasis seen in gliclazide patients probably result from a direct effect of the drug since hemobiological parameters and metabolic control parameters were not correlated.

Blood Glucose↗
PubMed1982

Antithrombin III and fibrinogen degradation product (fragment E) in diabetic nephropathy.

Plasma antithrombin III (AtIII), serum fragment E (FgE) and urine AtIII and FgE were measured in 25 diabetic patients with proteinuria above 1 g per day and compared to that in 25 patients with non-diabetic nephropathy, matched for the degree of proteinuria. Plasma AtIII concentrations were normal in both groups but FgE concentrations were increased. The level of plasma AtIII was directly related to HbA1 concentrations in the diabetics. For the same degree of proteinuria, the diabetic patients lost more AtIII and FgE in the urine. Urine AtIII was found to be mostly bound to activated procoagulants. Both urine AtIII and urine FgE correlated inversely with creatinine clearance. It was concluded that intraglomerular thrombosis probably contributes to the deteriorating renal function in diabetic nephropathy and is reflected in the concentrations of urine AtIII and FgE.

Adult↗
PubMed1982

Divergent effects of prolactin on estrogen and progesterone production by granulosa cells of rat Graafian follicles.

The effect of PRL on ovarian steroidogenesis was studied in cultured granulosa cells isolated from follicles of mature cycling rats on the morning of proestrus. Ovine PRL 10-1000 ng/ml) inhibited estradiol production but stimulated progesterone biosynthesis in a dose-dependent manner. The effect of PRL was most prominent after 4 days of culture: 1000 ng/ml PRL suppressed estradiol production by 80% but increased progesterone synthesis by 290%, whereas the lower dose of 10 ng/ml inhibited estrogen secretion by 20% without altering progesterone synthesis. The divergent effect of PRL was not shown to be species specific, since ovine, rat and human PRL had similar effects. Using increasing concentrations of androstenedione (the aromatase substrate), estrogen secretion remained suppressed and progesterone production was stimulated by PRL. FSH stimulated both estrogen and progesterone production. The FSH-induced increased in estrogen production was inhibited by concomitant treatment with PRL. In contrast, PRL and FSH had an additive action in stimulating progesterone production. Although LH alone had no effect on steroidogenesis, concomitant treatment with LH and PRL resulted in a stimulation of progesterone production that was additive. This study demonstrates that PRL acts directly on granulosa cells of Graafian follicles of adult cycling rats to stimulate the secretion of progesterone and to suppress estradiol production.

Androstenedione↗
PubMed1981

Antithrombin III, the major modulator of intravascular coagulation, is synthesized by human endothelial cells.

Human endothelial cells in culture is shown to synthesize antithrombin III (At-III). The endothelial cell At-III (EC-At-III) consists of a small fraction similar to plasma At-III and a larger fraction with decreased heparin-binding as tested by crossed immunoelectrophoresis. However, both the anti-Xa and thrombin-neutralizing activities of the EC-At-III were rapid and active even in the absence of added heparin. It is concluded that the major portion was probably bound to endogenous heparin-like substance, thus accounting for its decreased exogenous heparin binding. The presence of At-III and other antithrombotic factors in the vascular endothelium offer protection against thrombosis and possibly atherosclerosis.

Antithrombin III↗
PubMed1981

Incidence of hypothyroidism after radioactive iodine therapy for thyrotoxicosis in Hong Kong Chinese.

The incidence of hypothyroidism in 1396 Chinese patients in Hong Kong treated for hyperthyroidism with 131I therapy is presented using the life-table method of analysis. One year after therapy only 6% of patients were hypothyroid, but the subsequent annual incidence was 3.5%, emphasising the need for life-time surveillance of these patients. A higher incidence of subsequent hypothyroidism was found in patients with diffuse surgical treatment, the total dose or number of doses of 131I, the severity of thyrotoxicosis and the age of the patient did not influence the rate of onset of hypothyroidism. The data suggest that in order to minimise the occurrence of hypothyroidism a lower dose of 131I per gram of thyroid mass should be used for patients with small diffuse glands.

Adult↗
PubMed1981

Metabolism of antithrombin III in cirrhosis and carcinoma of the liver.

1. The metabolism of human antithrombin III (ATIII) was studied by using 125I-labelled tracer. 2. The plasma half-life (t0.5) was 2.71 +/- 0.26 days in normal subjects and was similar in patients with cirrhosis or primary carcinoma of liver. 3. Patients with cirrhosis had low ATIII levels, decreased intravascular mass, total body mass and decreased absolute catabolic rate, suggesting decreased synthesis. The positive correlation of ATIII level with fractional catabolic rate (K10) indicated that the decreased catabolic might exert a positive inhibition on ATIII production. 4. These abnormalities were more exaggerated in patients with macronodular cirrhosis associated with hepatitis surface antigen or in those with ascites. 5. In cirrhotic patients with ascites an additional extravascular pool of ATIII was present which did not turn over at the same rate as the intravascular pool. 6. Patients with primary carcinoma of liver had moderately low ATIII, but normal intravascular mass and total body mass because of the increased plasma volume and normal absolute catabolic rate. 7. The negative correlation of ATIII levels with K10 suggested that the low levels could be due to increased catabolism or consumption. 8. One patient with disseminated malignancy and active superficial thrombophlebitis had normal ATIII metabolism.

Antithrombin III↗
PubMed1981

Familial lymphedema praecox: Meige's disease.

Familial lymphedema should be classified in two categories depending on onset. Milroy's disease, or congenital hereditary lymphedema, is present from birth, painless, without tendency to ulcerate, and may have cholestasis or intestinal lymphangiectasia associated with it. Meige's disease, hereditary lymphedema praecox, is lymphedema with onset in the first or second decade, often presenting with inflammation, and may have a number of associated related anomalies including distichiasis, extradural cysts, vertebral anomalies, cerebrovascular malformation, yellow nails, and sensorineural hearing loss. Both types follow an autosomal dominant pattern. This paper presents a family of 39 persons in 5 generations with 13 affected persons having Meige's disease. The importance of recognizing this type of familial lymphedema is discussed.

Adult↗