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Biomedical subjects

J Vallance-Owen

Publications and source records attributed to J Vallance-Owen.

At least 19 recordsLinked to original sources
PubMed1989

Prognostic index in prediction of mortality from infective endocarditis.

Out of 176 patients with infective endocarditis complicating rheumatic (120) and congenital heart disease (38), mortality occurred in 35 patients (19.9%). Presence of leukocytosis, heart failure, major embolisation and isolation of certain organisms including Staphylococci, beta-haemolytic Streptococci, Pseudomonas and Klebsiella were ominous with higher mortality rates compared with those when they were absent (P less than 0.02). Stepwise logistic multiple regression was then applied and the four most important independent variables were identified. A prognostic index for the prediction of mortality for infective endocarditis was then constructed by the summation of the regression coefficients. By applying this index, patients with infective endocarditis could be divided into subgroups with increasing proportional mortality from 5.8 to 83.3%. It provides an objective assessment of the risk patients with infective endocarditis, and a more reliable evaluation of benefit of any new treatment regimen, including cardiac surgery, during the acute stage.

Endocarditis, Bacterial↗
PubMed1989

Validation of a coronary prognostic index for the Chinese--a tale of three cities.

In order to confirm the efficacy of a new coronary prognostic index for the prediction of mortality of acute myocardial infarction in the Chinese in general, this index was applied to 886 patients from six general hospitals in Hong Kong (435 patients), Guangzhou (212 patients) and Shanghai (239 patients), respectively. They could be successfully stratified into seven clinical subsets with stepwise increasing mortality. The overall mortality tallied with that predicted by the original coronary prognostic index. The efficacy of this prognostic index for the prediction of mortality from acute myocardial infarction among the Chinese is verified and its application in the objective assessment of patients with acute myocardial infarction is recommended.

Adult↗
PubMed1988

The prevalence and pattern of pulmonary thromboembolism in the Chinese in Hong Kong.

The prevalence and clinical pattern of pulmonary thromboembolism was studied by a multifaceted approach. This documented the occurrence of pulmonary thromboembolism among the Chinese and confirmed an increasing incidence in Hong Kong, although comparatively it was still much lower (about one-tenth) than that found in western communities. Their clinical pattern, regarding presentation, risk factors, clinical features and response to thrombolytic therapy, conformed well with those reported in the west, but perhaps appeared in a milder form. The strong association of pulmonary thromboembolism with varicose veins and immobilisation would appeal for recommending routine heparinisation in Chinese patients having these combinations. Our findings will stimulate more interest in the comparative study of the haematological profile and the ethnic particulars of the Chinese.

Adult↗
PubMed1988

Strong association between IgA nephropathy and hepatitis B surface antigenemia in endemic areas.

The frequency of hepatitis B surface antigen (HBsAg) was studied in the sera of 122 patients with primary IgA nephropathy. Hepatitis B surface (HBs) antigenemia was detected in 21 patients (17.2%) and this was significantly higher than the prevalence of HBsAg carrier in the general population (p less than 0.01). These patients had no clinical or laboratory findings to suggest acute or chronic liver diseases. Two glomerulopathic entities: mesangial proliferative glomerulonephritis with predominant mesangial IgA deposits and a mixed picture of membranous nephropathy with capillary IgG deposits and mesangial proliferative glomerulonephritis with mesangial IgA deposits, were observed in this group of patients. Glomerular deposits of HBsAg, hepatitis B core antigen (HBcAg), and both HBsAg and HBcAg were detected in three, five and four renal biopsy specimens respectively. Replication of hepatitis B virus (HBV) was suggested in two of the six renal biopsy specimens examined by HBV DNA gene probe. During the mean study period of 40 months (range 12-84), 19% of these patients with hepatitis B virus-associated IgA nephropathy developed progressive renal deterioration and one required maintenance dialysis therapy. Our study suggests that hepatitis B virus antigenemia may play a significant pathogenetic role in the development of IgA nephropathy in areas of high HBV endemicity and these HBV-associated IgA nephropathies can run an indolent but relentless slowly progressive clinical course.

Adult↗
PubMed1987

Cyclosporin treatment of IgA nephropathy: a short term controlled trial.

Cyclosporin's known regulatory effects on the immune system suggest that it may be useful in treating patients with IgA nephropathy. A randomised prospective single blind study of 19 patients with IgA nephropathy and proteinuria (greater than 1.5 g/day) was conducted to determine the therapeutic value of cyclosporin. The patients were divided into two groups: nine patients were given oral cyclosporin (5 mg/kg/day) for 12 weeks and 10 patients a placebo. The two groups were comparable in age of presentation, ratio of men to women, plasma creatinine and serum IgA concentrations, creatinine clearance, daily urinary protein excretion, severity of renal histopathological changes, and prevalence of hypertension. A significant reduction of proteinuria and an increase of plasma albumin concentration was observed with treatment with cyclosporin. Nevertheless, a significant rise of plasma creatinine concentration and a fall in creatinine clearance was found in patients after six weeks' treatment with cyclosporin, although the plasma cyclosporin concentrations were maintained within a narrow therapeutic range. Serum IgA concentrations were reduced in seven patients. Renal function improved within eight weeks after treatment was stopped. Three months after treatment was stopped proteinuria remained less than half of the pretreatment values in three patients. No similar biochemical changes were observed in the controls. Short term cyclosporin therapy may be beneficial in reducing proteinuria in some patients with IgA nephropathy. As transient renal impairment was seen, despite cyclosporin concentrations being maintained within a narrow therapeutic range, indiscriminate use of cyclosporin in glomerulonephritis should be discouraged.

Adolescent↗
PubMed1987

The prevalence of diabetes mellitus and an assessment of methods of detection among a community of elderly Chinese in Hong Kong.

This study provides information on the prevalence of diabetes mellitus in a group of elderly Chinese subjects aged 60 and above living in the community in Hong Kong, and investigates the sensitivity of the urine sugar, random blood glucose, glycosylated haemoglobin, and fructosamine measurements compared to a glucose tolerance test in screening for diabetes mellitus in this population. Four hundred twenty-seven subjects aged 60 and above were studied. The National Diabetes Data Group Criteria were used for the diagnosis of diabetes. Those with a random blood glucose exceeding 12.5 mmol/l were considered diabetic, and all of these patients had glycosuria together with elevated total glycosylated haemoglobin and fructosamine concentrations. A diagnostic 75 g oral glucose tolerance test was performed on patients with one or more of the following abnormalities: glycosuria, random plasma blood glucose 7.8 mmol/l to 12.5 mmol/l, glycosylated haemoglobin 8.5%, and fructosamine 2.20 mmol/l. By these criteria, the prevalence of diabetes in this community was found to be 9.8%. An elevated random glucose greater than 11.1 mmol/l proved to be the only specific method of screening and glycosuria was found to be at least as good as fructosamine and HbA1. However, HbA1 is more sensitive than random glucose, glycosuria or fructosamine in detecting impaired glucose tolerance. On the basis of this study, a higher reference range for glycosylated haemoglobin for the elderly alone is also suggested (5.74-9.34%).

Aged↗
PubMed1987

Plasma exchange in patients with rapidly progressive idiopathic IgA nephropathy: a report of two cases and review of literature.

Primary IgA nephropathy is generally considered an indolent disease, but progression to chronic renal failure is not uncommon, and a rapidly progressive course is observed in some cases, especially when extensive fibrocellular crescents are present. The therapeutic benefit of immunosuppression and plasma exchange remains controversial. We described two patients with primary IgA nephropathy and rapidly progressive renal failure. Both patients showed extensive glomerulosclerosis and crescent formation in their renal biopsies. Corticosteroid and immunosuppressive therapy failed to control the progression of the disease, and plasma exchanges were performed. In both cases, the serum creatinine and creatinine clearance initially improved with plasma exchange and the rapid progression of renal failure was apparently halted. In one patient, the serum creatinine rose when treatment was discontinued and fell again when plasma exchange was recommenced. Nevertheless, the long-term benefit of plasma exchange in crescentic IgA nephropathy was unsatisfactory as the renal function continued to deteriorate in the following 12 months despite an initial stabilization.

Adult↗
PubMed1987

Insulin binding and effects on pyrimidine nucleoside uptake and incorporation in cultured mouse astrocytes.

Binding of 125I-insulin to primary cultures of differentiated mouse astrocytes was time-dependent, reaching equilibrium after 2 h at 22 degrees C, with equilibrium binding corresponding to 20.79 fmol/mg of protein, representing approximately 5,000 occupied binding sites/cell. The half-life of 125I-insulin dissociation at 22 degrees C was 2 min, with an initial dissociation rate constant of 4.12 X 10(-2) s-1. Dissociation of bound 125I-insulin was not accelerated significantly in the presence of unlabeled insulin (16.7 microM). Porcine and desoctapeptide insulins competed for specific 125I-insulin binding in a dose-dependent manner, whereas growth hormone, glucagon, and somatostatin did not. For porcine insulin, Scatchard analysis suggested multiple-affinity binding sites (high-affinity Ka = 4.92 X 10(8) M-1; low-affinity Ka = 0.95 X 10(7) M-1). After incubation with insulin (0.5 microM) for 2 h at 37 degrees C, increases above basal values of 254 +/- 23 and 189 +/- 34% for [3H]uridine uptake and incorporation, respectively, were observed. After incubation with insulin (0.5 microM) for 24 h at 37 degrees C, there were increases of 145 +/- 6% for [3H]thymidine uptake and 166 +/- 11% for thymidine incorporation. Basal and stimulated uridine and thymidine uptake and incorporation were inhibited by 50 microM dipyridamole. These studies confirm that mouse astrocytes in vitro possess specific insulin receptors and demonstrate an effect of insulin on pyrimidine nucleoside uptake and incorporation.

Animals↗
PubMed1987

Massive hollow fiber clotting: a distinct problem in treatment of cryoglobulinemia by membrane plasmapheresis.

Two patients with cryoglobulinemia were treated with plasmapheresis in combination with immunosuppressive therapy. One had Waldenstrom's macroglobulinemia, and the other suffered from systemic lupus erythematosus. Membrane plasmapheresis, using membrane plasma separators, was performed, and the initial plasmapheresis treatments were unsatisfactory because of clotting of hollow fibers by cryoglobulin. The plasma filtration rate and the clearance of immunoglobulins fell rapidly with the clotting of the hollow fibers. This technical difficulty was overcome by prediluting the blood with normal saline before passing it through the membrane plasma separator. The mechanism of preventing clotting of hollow fiber by saline predilution is likely to be the reduction of serum viscosity and the lowering of cryoglobulin concentration. This modification is simple and efficient and enables membrane plasmapheresis to be performed effectively in patients with cryoglobulinemia without complicated and expensive machines.

Blood Coagulation↗
PubMed1987

Pattern of glomerulonephritis in Hong Kong.

A retrospective analysis of all renal biopsies (961) performed in two regional hospitals in Hong Kong during 1977-1985 revealed that IgA nephropathy was the most frequently encountered glomerulopathy. Lipoid nephrosis (minimal change nephrotic syndrome) remained the commonest cause of nephrotic syndrome in children. The frequencies of mesangiocapillary glomerulonephritis, focal glomerulosclerosis, and idiopathic membranous nephropathy were lower than in other populations. Membranous nephropathy was frequently associated with hepatitis B virus antigenemia, especially in children. Other chronic infections did not have a significant pathogenetic role in glomerular diseases. Lupus nephritis was the commonest secondary glomerular disease in our study, and over seventy percent of the renal biopsies showed advanced pathologies with either diffuse proliferative glomerulonephritis or membranous nephropathy.

Adolescent↗
PubMed1987

A single-blind, randomized, cross-over study of angiotensin-converting enzyme inhibitor and triamterene and hydrochlorothiazide in the treatment of mild to moderate hypertension in the elderly.

Forty patients over 70 years old with a diastolic blood pressure of 95 to 110 mm Hg and/or a systolic blood pressure of 170 to 220 mm Hg after two weeks' placebo therapy underwent a single-blind, placebo-controlled, randomized cross-over study using captopril and triamterene and hydrochlorothiazide (Dyazide). Blood pressure was lowered from a mean of 189 +/- 2.0/92 +/- 1.7 mm Hg (mean +/- SEM) to 161 +/- 2.8/78 +/- 1.7 mm Hg with captopril therapy, and therapy with triamterene and hydrochlorothiazide produced similar reductions (156 +/- 2.7/78 +/- 1.7 mm Hg). Two patients on triamterene and hydrochlorothiazide therapy withdrew because of side effects, while only minor side effects were observed with captopril therapy. Therapy with triamterene and hydrochlorothiazide produced significant elevation of urea, creatinine, and uric acid, while captopril therapy produced no biochemical or hematologic changes. A single daily dose of captopril alone was sufficient to normalize the blood pressure in 31 (75%) of 40 patients. Captopril appears to be a promising monotherapy for the elderly with mild to moderate hypertension.

Aged↗