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Biomedical subjects

S D Roberts

Publications and source records attributed to S D Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1987

Viral antibody titers. Comparison in patients with multiple sclerosis and rheumatoid arthritis.

Higher titers of antibodies to measles virus envelope antigens, hemolysin and hemagglutinin, Epstein-Barr virus (EBV) capsid antigen and nuclear antigen, and rubella virus hemagglutinin were demonstrated in serum samples of patients with multiple sclerosis and rheumatoid arthritis than in age- and sex-matched control subjects. A significant correlation was observed between antibodies to measles and rubella viruses both in patients with multiple sclerosis and rheumatoid arthritis, but such a correlation was not observed between antibodies to EBV and measles or rubella viruses. Whether elevated levels of antibodies to EBV are due to reactivation of the virus, or elevated levels of antibodies to all the enveloped viruses result from cross-reactions between viruses and host tissue, or perhaps reflect defects in immunoregulation, needs further investigation.

Adult↗
PubMed1987

Cost-effectiveness analysis of patient management alternatives after uncomplicated myocardial infarction: a model.

Quantitative decision analyses provide a means whereby the effectiveness, in terms of patient outcome, and costs of diverse clinical approaches to the care of patients with cardiovascular disease can be made explicit and understandable. Increasingly, the profession is being required to justify the costs of clinical care to society, government and third party payers. Such justifications can be effectively presented when structured in decision analytic format. To demonstrate the utility of decision analysis and its extension--cost-effectiveness analysis--as a technique for presenting the rationale for clinical practices and technology utilization, the Cardiovascular Norms Committee of the American College of Cardiology sponsored a model cost-effectiveness analysis. Alternative management options, 6 month mortality and costs for the post-myocardial infarction patient were compared. The options included exercise electrocardiography, exercise thallium scintigraphy and coronary angiography, followed by coronary artery bypass surgery for patients with left main coronary disease only or patients with left main disease, three vessel disease or single or double vessel disease and a significant amount of myocardium in jeopardy. Within the constraints of the model, proceeding directly to angiography for risk stratification was the most effective approach, lowering expected mortality from 8% to approximately 3%. The marginal costs for this strategy, however, were high. The most cost-effective approach was to screen patients initially with exercise electrocardiography.

Angiography↗
PubMed1987

The pharmacokinetics of sulphasalazine in young and elderly patients with rheumatoid arthritis.

The clinical pharmacokinetics of enteric-coated sulphasalazine (Salazopyrin-EN) were studied after acute and chronic dosing in 20 patients with 'active' rheumatoid arthritis. 12 elderly (mean age 74.4 +/- 1 yr; range 71-83) and 8 young (mean age 40.5 +/- 1.4 yr; range 35-46) patients were given a single 2 g oral dose of sulphasalazine after an overnight fast. Serum and urine samples were collected at regular intervals over a 96 hour period for estimation of concentrations of sulphasalazine, sulphapyridine and its metabolites. This procedure was repeated after 17 days of continuous treatment with salazopyrin-EN 2 g daily in order to compare the drug's kinetics at 'steady-state'. Whilst the interindividual variation in kinetic parameters was large, age and acetylator status had a significant influence on a number of factors. The elimination half-life of sulphasalazine was prolonged in the elderly whilst renal clearance was increased in slow acetylators at 'steady-state'. The tmax and apparent volume of distribution of sulphapyridine were increased in the elderly after a single drug dosage but these differences disappeared with regular dosing. The Cmax, elimination half-life, 'steady-state' serum concentration, apparent volume of distribution and total clearance of sulphapyridine were all affected by acetylator status. We conclude that old age has only a minor effect on the body's handling of sulphasalazine and sulphapyridine but that acetylator phenotype plays a significant role in determining the 'steady-state' serum concentrations of sulphapyridine. This is likely to have practical implications with regard to some of the drug's adverse effects.

Acetylation↗
PubMed1986

Glycosaminoglycans content of stone matrix.

The role of urinary glycosaminoglycans (GAGs) in lithogenesis is a topic of current interest in urologic research. One GAG, chondroitin sulfate, has previously been shown to inhibit calcium oxalate crystal formation. It has long been known that the chemical components of GAGs are present in the matrix of urinary concretions, but it has not been determined whether these components exist in free form or as constituents of GAG. This study was undertaken to determine whether GAGs are present in urinary stone matrices and, if so, to characterize them. Matrices of nine single urinary stones of various compositions and of three stone pools (calcium oxalate, magnesium ammonium phosphate) were isolated by exhaustive dialysis. The techniques of cellulose acetate electrophoresis, Alcian blue staining and enzymatic degradation were used to identify various GAGs. Material that stained Alcain blue was present in eleven of twelve samples. GAG was detected as this material in ten samples. The GAGs identified are heparan sulfate, hyaluronic acid and possibly keratan sulfate. The most prominent urinary GAG, chondroitin sulfate, was notably absent from urinary stone matrix. GAG seems to be incorporated into matrix on a selective basis. This finding may be due to differences in the affinities of different GAG species for the crystals which comprise the calculi. It has been proposed that the inhibitory activity of GAGs lies in their ability to bind to (and therefore block) the growth sites of crystals. It is apparent from this study that certain GAG species are incorporated into the structure of the stone and they may be intimately related to stone development and growth.

Calcium Oxalate↗
PubMed1986

Multicentre study of piroxicam versus naproxen in juvenile chronic arthritis, with special reference to problem areas in clinical trials of nonsteroidal anti-inflammatory drugs in childhood.

Clinical trials of nonsteroidal anti-inflammatory drugs (NSAIDs) are necessary in juvenile chronic arthritis (JCA) but pose certain problems highlighted and discussed in this study, including recruitment, the assessment of efficacy, and the heterogeneity of the disease. In a multicentre 8-week double-blind cross-over study using the double-dummy technique, piroxicam was compared with naproxen in 47 children with seronegative JCA aged 5-16 years. No significant difference between the two treatments was found in either the clinical variables measured or the parent/patient and physician preference at the end of the study. Side-effect profiles of the two drugs were similar, mainly gastrointestinal disturbances. Piroxicam may be a useful alternative NSAID in JCA, particularly in view of its once-daily dosage.

Adolescent↗
PubMed1986

Behçet's disease presenting as benign intracranial hypertension.

Two siblings with Behçet's disease presenting as benign intracranial hypertension are reported and the literature is reviewed. We suggest that raised intracranial pressure should be added to the clinical criteria considered for the diagnosis of Behçet's disease.

Adult↗
PubMed1986

Cost-effectiveness of culturing for Chlamydia trachomatis. A study in a clinic for sexually transmitted diseases.

We have evaluated the cost-effectiveness of using cell culture to test for chlamydial infections in 9979 patients at a clinic for sexually transmitted diseases. From results of cultures, we have established prevalence data and, using decision-theory analysis, have calculated costs and probabilities of various outcomes. According to their histories and presenting signs and symptoms, patients were classified as at high or low risk for chlamydial infections. Empiric treatment of all patients attending the clinic was the most cost-effective strategy, followed by empiric treatment of high-risk women and culture-based treatment of low-risk women. Obtaining cultures for men at high and low risk was not cost-effective. If universal treatment is not provided, the most cost-effective strategy appears to be empiric therapy in patients at high risk for chlamydial infections and therapy based on diagnostic test results in women at low risk.

Adolescent↗
PubMed1986

Clinical and laboratory characteristics of patients with speckled pattern antinuclear antibodies.

Fifty patients whose sera contained a speckled antinuclear antibody (ANA) were interviewed and examined to determine if there was any relationship between their clinical manifestations and the presence of certain serological markers. The results suggest that speckled ANA is usually found in patients with definite connective tissue diseases, but a significant minority have incomplete or early stages of these diseases. Characterisation of the antibody to extractable nuclear antigen (ENA) and other serological markers does not normally assist in making a clinical diagnosis, but the detection of a speckled ANA should prompt further investigation and careful follow-up.

Adolescent↗
PubMed1985

Detection and partial characterization of human B cell colony stimulating activity in synovial fluids of patients with rheumatoid arthritis.

The joint fluids of 37 patients with rheumatoid arthritis, eight patients with traumatic injuries to their joints, two patients with Reiter's syndrome and three patients with psoriatic arthritis were tested for the presence of B cell colony stimulating activity (B cell CSA). B cell CSA was found in all of the joint fluids from the patients with rheumatoid arthritis but in none of the joint fluids from patients with traumatic injuries to their joints or in the joint fluids from the patients with Reiter's syndrome. A trace of B cell CSA was found in the joint fluid of one of the three patients with psoriatic arthritis. There was a positive correlation (r = 0.796) between the amount of rheumatoid factor present in the joint fluids and the titre of B cell CSA. This correlation was highly significant (P less than 0.001). The B cell CSA was localized to component(s) with molecular weight ranges 115-129 kD and 64-72 kD and an isoelectric point of 6.8. Its activity was sensitive to reduction with 2-mercaptoethanol and to the oxidising action of potassium periodate.

Adult↗
PubMed1984

The role of gallium scanning in the detection of bone and joint sepsis.

The value of gallium ((67)Ga) scanning in the diagnosis of septic disease of bone or joint was assessed in 34 patients. The results show a sensitivity of 60 per cent and specificity of 64 per cent. The low accuracy of this method for the detection of bone and joint sepsis (62 per cent) means that gallium scanning can be used only as an adjunct to other investigative techniques.

Adolescent↗
PubMed1983

Unexpected hospital admissions among patients with diabetes mellitus.

In a search for a new way to recognize the patients who are at higher risk of unexpected hospitalizations, the characteristics of patients with diabetes mellitus were examined after their last office visit prior to hospitalization. Six characteristics contributed significantly in distinguishing 256 patients who were subsequently hospitalized from 512 patients who were not. The six characteristics included the following: frequent emergency room visits, low serum albumin level, cardiomegaly, anemia, hypotension, and hyperglycemia. The sensitivity of prediction was 43.2%, specificity was 77.4%, and the relative risk by odds ratio was 2.60:1. The intensity of care, as estimated by the level of the provider, and the intended intensity of care, as measured by the scheduled return-visit interval, were not clinically consistent with the magnitude of risk. The characteristics of patients at higher risk of unexpected hospitalizations were identified and provide a direction for increased intensity of ambulatory care.

Aged↗