We describe the interlaboratory testing of a candidate Reference Method (Part I) for uric acid in serum. The method is based on the ultrasound spectrophotometric quantitation of uric acid before and after incubation with uricase. A comprehensive investigation involving 12 laboratories was organized to document the transferability, intra- and interlaboratory precision, and general reliability of the candidate Reference Method. The interlaboratory CV with this method was about 2 to 6% for uric acid concentrations ranging from 0.12 to 0.60 mmol/L. The results detailed here demonstrate that the method can be successfully duplicated among different laboratories.

Evaluation Studies as Topic↗

PubMed1980

Aortocoronary bypass procedures and sternotomy infections: a study of antistaphylococcal prophylaxis.

In a prospective study of cephalothin prophylaxis for patients who underwent aortocoronary bypass an unacceptably high rate (44%) of Staphylococcus aureus sternotomy infections occurred in a placebo-treated group. In two other groups of patients, one group given cephalothin intraoperatively and the other given the antibiotic both intra- and postoperatively, such infections occurred with similar frequency (2.6% and 2.1% respectively). This study demonstrates the need for antistaphylococcal agents during aortocoronary bypass operation. No advantage is derived by extending this therapy beyond the operative period.

Aged↗

PubMed1971

DDT residues: distribution of concentrations in Emerita analoga (stimpson) along coastal California.

The total concentrations (tDDT) of DDT [1,1,1-trichloro-2,2-bis(pchlorophenyl)ethane], DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethanel, and DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] in Emerita analoga from 19 California beaches reflect tDDT contamination nearby. Animals near the Los Angeles County sewer outfall contain over 45 times as much tDDT as animals near major agricultural drainage areas. Sediments near the outfall probably contain over 100 metric tons of tDDT-a reservoir for input into marine organisms. The effluent from a plant that manufactures DDT is a probable source.

Animals↗

PubMedDate not supplied

Adjusting for temporal variation in the analysis of parallel time series of health and environmental variables.

Time series of daily administrative cardio-respiratory health and environmental information have been extensively used to assess the potential public health impact of ambient air pollution. Both series are subject to strong but unrelated temporal cycles. These cycles must be removed from the time series prior to examining the role air pollution plays in exacerbating cardio-respiratory disease. In this paper, we examine a number of methods of temporal filtering that have been proposed to eliminate such temporal effects. The techniques are illustrated by linking the number of daily admissions to hospital for respiratory diseases in Toronto, Canada for the 11 year period 1981 to 1991 with daily concentrations of ambient ozone. The ozone-hospitalization relationship was found to be highly sensitive to the length of temporal cycle removed from the admission time series, and to day of the week effects, ranging from a relative risk of 0.874 if long wave cycles were not removed at all to 1.020 for models which removed at least cycles greater than or equal to one month based on the interquartile pollutant range. The specific statistical method of adjustment was not a critical factor. The association was not as sensitive to removal of cycles less than one month, except that negative autocorrelation increased for series in which cycles of one week or less were removed. We recommend three criteria in selecting the degree of smoothing in the outcome: removal of temporal cycles, minimizing autocorrelation and optimizing goodness of fit. The association between ambient ozone levels and hospital admissions for respiratory diseases was also sensitive to the season of examination, with weaker associations observed outside the summer months.

Air Pollution↗

PubMedDate not supplied

Air pollution exposures and children's health.

The evidence from a large number of studies indicates that exposures to current outdoor air pollution increase respiratory morbidity in children. Children with asthma, and those with asthma-like symptoms but without a diagnosis of asthma, are considered to be at highest risk of experiencing short-term and/or longer-term adverse health effects. Many outdoor air pollutants readily penetrate indoors. Indoor air quality can deteriorate quickly when persistent and uncontrolled emissions occur and the ventilation/air exchange rate is reduced. It has been estimated that children spend 90% of their time indoors, including in school buildings, vehicles and public indoor environments. Environmental tobacco smoke is a well-recognized persistent indoor air contaminant with adverse health effects in children of all ages. Uncontrolled moisture in the indoor environment is increasingly recognized to significantly increase the risk of respiratory morbidity in children. The evidence that air pollutants singly and in combination with other environmental factors elicit adverse health responses in asthmatic and non-asthmatic children and adolescents, appears irrefutable.

Air Pollutants↗