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Biomedical subjects

R W Thomas

Publications and source records attributed to R W Thomas.

35 records · Page 2Linked to original sources

Space-time interaction in Hodgkin's disease in Greater Manchester.

Knox's test for space-time interaction was applied to 922 cases of Hodgkin's disease which, according to the North Western Regional Cancer Registry, had presented in 1962-76 among the population of the region known before 1974 as the South East Lancashire Conurbation. In the series as a whole, there were statistically significant excesses of pairs of patients separated by time intervals of less than a year and distances of less than 1 km. Analysis by age and sex indicated that this clustering involved (a) a trio of young females and (b) pairs involving adults over 45 years old. No evidence was detected of any clustering by histological subtype or of any tendency for cases close in space to be separated by long time intervals of specific duration. These findings lend support to the idea that at least some cases of Hodgkin's disease may be induced by an infection or other environmental influence, but they do not suggest that such an infection has a long and specific incubation period.

Adolescent↗

High-performance liquid chromatographic-ultraviolet determination of primaquine and its metabolites in human plasma and urine.

A high-performance liquid chromatographic method was developed for the simultaneous determination of primaquine and its metabolites from plasma and urine samples obtained after oral administration of primaquine diphosphate. Following partial deproteinization with acetonitrile, samples were chromatographed by direct injection onto a cyano column with UV detection at 254 nm. Levels as low as 100 ng/mL per 20-microL injection were quantitated. Preliminary pharmacokinetic analysis is reported for two human volunteers after oral doses of 60 mg and 90 mg. Two apparent plasma metabolites and two possible urinary metabolites of primaquine are also reported.

Chromatography, High Pressure Liquid↗

Lincomycin dose response for treatment of necrotic enteritis in broilers.

A dose response study was conducted to determine the appropriate (optimal) lincomycin concentration in drinking water for the treatment of necrotic enteritis (NE) in broilers. The study was replicated twice over time using a total of 2,895 broilers. Birds were raised in a facility containing a built-up litter from a source that experienced NE. They were commingled from 1 day of age until NE was observed. Lincomycin was mixed in drinking water at a rate of 0, .528, 2.114, 8.454, or 33.818 mg/liter for a period of 7 days. The study was terminated 3 weeks after initiation of therapy. Necrotic enteritis was diagnosed by mortality and pathological findings. The data on mortality were analyzed statistically using analysis of variance procedures. The Walker-Carmer technique was applied to estimate the appropriate lincomycin concentration. Lincomycin was effective for the treatment of NE in broilers at concentrations of greater than or equal to 2.114 mg/liter of drinking water. The minimal effective dose that would achieve maximal treatment response (optimal dose) against NE in broilers was estimated to be 16.9 mg lincomycin/liter of drinking water.

Animals↗

Therapeutic effect of optimal lincomycin concentration in drinking water on necrotic enteritis in broilers.

The efficacy of 16.9 mg lincomycin/liter of drinking water was evaluated for the treatment of necrotic enteritis (NE) in 743 broiler-type chickens. Birds were raised in a facility containing a built-up litter obtained from a source that experienced NE. They were commingled from 1 day of age until NE was observed. Two groups of 6 pens each were given 0 or 16.9 mg lincomycin/liter of drinking water. Water medication was offered fresh daily for 7 days and the study was terminated 3 weeks after initiation of therapy. The susceptibility of Clostridium perfringens to lincomycin was determined in vitro. The test organism was susceptible to lincomycin as reflected by minimal inhibitory concentration and minimal lethal concentration of .156 microgram/ml. Mortality attributed to NE was 0% in lincomycin treated birds and 14% in nonmedicated control birds (P less than .01). Lincomycin water medication was highly effective for the treatment of NE in broilers.

Animals↗

Effects and handling of almitrine bismesylate in healthy subjects.

Almitrine bismesylate was administered to young, healthy, non-smoking male subjects as single oral doses, multiple oral doses and multiple oral doses with food. A variety of physiological parameters and blood parameters were tested at specified times in relationship to drug ingestion, and multiple blood samples for plasma almitrine bismesylate levels were obtained. Evaluation of the data revealed almitrine bismesylate to be safe at all doses tested, up to 400 mg per day, with symptoms of mild nausea and headache occurring most frequently when the drug was administered in the fasting state. A striking complaint of shortness of breath on exertion was reported by subjects, with increased frequency and severity related to total amount of drug ingested and level of physical activity. Increased oxygen uptake and tidal volume were found after multiple oral dosing. Plasma almitrine bismesylate levels were highly variable, and marked individual differences in peak levels and terminal phase rate constants and half lives were found. Multiple oral dosing, either fasting or with food, significantly prolonged the terminal phase half life when compared to single oral dosing.

Adult↗

The interaction of spironolactone and digoxin: a review and evaluation.

A review of the literature describing the interaction of digoxin and spironolactone is presented. Two mechanisms of possible interaction are discussed. Spironolactone and its metabolites may interfere with digoxin radioimmunoassay or alter the pharmacokinetics of digoxin. The occurrence of either or both of these processes may make interpretation of serum digoxin levels difficult.

Digoxin↗

An in-house industrial counseling program: the Northwestern Bell Telephone Company experience.

Development of a counseling program at Northwestern Bell Telephone in the state of Iowa began in 1970. Since its inception, the program has expanded to assist nearly 2000 individuals per year with varying problems. It is not the first counseling program for employees (other programs are described in the paper), but it is unique in its availability to all employees in the state, with counselors strategically placed in the major districts of the Bell System. Because of its concern for human resources, the company supported the medical department in establishing the counseling program. The management has been supportive and noninterfering. The numbers of employees using the program and their responses to questionnaires indicate the need for the service. The advantages and costs of an in-house counseling service are discussed.

Costs and Cost Analysis↗

Microbiological method for assaying lincomycin in animal feed: collaborative study.

A microbiological assay for determining lincomycin in swine feed, supplement, and a vitamin-mineral premix was studied collaboratively in 16 laboratories. The design of the study involved a complete feed, feed supplement, and a vitamin-mineral premix covering a range of fortification from 20 to 80 g/ton and 80 to 2600 g/ton. Two methods of sample preparation were used depending on the concentration of lincomycin in the sample. Statistical evaluation of the results from the 2 methods indicated that 10 and 11 collaborators, respectively, had mean recoveries which were not significantly different from one another. Ten laboratories obtained a mean recovery of 112.2% (range 102.3--123.5%) for the lower level, and 11 laboratories obtained a mean recovery of 104.4% (range 100.0--107.7%) for the higher level. The method has been adopted as official first action.

Animal Feed↗

Avascular necrosis of the hip.

Avascular necrosis is a common problem and can be a grossly disabling condition in young patients. Magnetic resonance imaging has revolutionized the diagnosis and assessment of early cases. Core decompression of the femoral head may promote venous drainage and reduce the risk of progressive collapse towards osteoarthritis. However, the authors favour early total joint replacement in patients who are greatly incapacitated.

Adult↗