PubMed Health⌕ Search

Biomedical subjects

J C Reading

Publications and source records attributed to J C Reading.

45 records · Page 3Linked to original sources
PubMed1977

Airborne arsenic exposure and excretion of methylated arsenic compounds.

First void urine samples were collected from copper smelter workers exposed to inorganic arsenic and from unexposed controls. Arsenic compounds (As (III), As (V), methylarsonic acid and dimethylarsinic acid) in these samples were analyzed by selective volatilization as arsines with determination of arsenic by plasma excitation emission spectrometry. On the day preceding the urine sample collection a breathing zone measurement was made of respirable arsenic particulates for each subject. It was found that all of the subjects, including the controls excreted arsenic primarily as methylated species. Approximately 50% of the total arsenic was excreted as dimethylarsinic acid and 20% as methylarsonic acid. Slight differences in the proportion of various arsenic compounds were observed with varying levels of inorganic arsenic exposure. Amounts of arsenic species were all closely correlated with each other and with exposure. Irrespirable particulate exposures were measured on a subset of high exposure workers. Irrespirable arsenic was found to be more closely correlated with excretion of arsenic compounds than was respirable arsenic.

Adult↗
PubMed1976

Pulmonary effects of chronic exposure to airborne cadmium.

Workers chronically exposed to high concentrations of airborne cadmium showed a significantly decreased forced vital capacity relative to a low-exposure group and had Po2 values in the normal range, but at the extreme low end. They had no significant decrease in 1-sec forced expiratory volume or maximal mid-expiratory flow. Chest roentgenograms showed mild or moderate interstitial fibrosis in 29 per cent of the group exposed to cadmium. Collectively, these results suggest a mild fibrotic reaction associated with exposure to cadmium. A dose-response association was observed between forced vital capacity, expressed as per cent predicted, and both average urinary cadmium concentration (P less than 0.003; r=-0.53) and maximal urinary cadmium concentration (P less than 0.005; r=-0.51). Further, a dose-response relationship was found between the forced vital capacity and months of work in cadmium fume areas, but not for months of exposure to cadmium sulfate aerosol.

Air Pollutants↗
PubMed1976

Cadmium, lead, and copper blood levels in normal children.

Cadmium, lead, and copper levels were measured in duplicate whole blood samples from 60 apparently normal children, ranging in age from 2 months to 13 years, who were hospitalized for elective surgery. Metals were measured by atomic absorption spectroscopy after the samples were chemically oxidized and digested. Cadmium was concentrated by dithizone extraction before analysis. Blood cadmium averaged 0.66 mug/100 gm, with a standard deviation of 0.25. No samples had cadmium concentrations less than could be detectable. The average concentration of lead was 15.7 mug/100 gm with a standard deviation of 6.33. Copper averaged 123 mug/100 gm with a standard deviation of 35.5. Tolerance intervals were calculated for each metal in order to estimate the bounds of whole blood metal values in normal children. The intervals containing 95% of normal values with a probability of .95 were 0.22-1.70 mug Cd/100 gm, 0.87-30.5 mug Pb/100 gm, and 40.0-206 mug Cu/100 gm.

Adolescent↗
PubMed1975

The prognosis in aplastic anemia.

The biphasic shape of the survival curve of 99 patients with aplastic anemia suggested that there may be at least two subgroups of patients with this disease, one with a very short survival and another with a longer survival. Patients who survived for 4 mo or less after the first clinic visit (group A) were different from the patients who survived longer (group B) with respect to their modes of onset, sex, intervals from the onset of symptoms to first clinic visit, and initial hematologic values. These differences suggested that short survival could be predicted from data available at the first contact with the physician. From these measurements, a prognostic index could be calculated which was useful in identifying the patients in group A. Although this method of prognostication needs further testing, if validated, it may prove useful in selecting patients for therapeutic trials and could explain the divergent results in previous studies of androgen treatment of aplastic anemia. When our androgen-treated subjects were compared with subjects with a similar prognostic index who had not received androgens, a beneficial effect of androgen therapy on survival could not be demonstrated.

Anemia, Aplastic↗
PubMed1973

Validation of a "clearing" assay for milk lipoprotein lipase in agarose gel.

We have developed a simplified method for the quantitative assay of lipoprotein lipase in cow's milk based on the hydrolysis of a glyceride emulsion in semisolid agarose gel. The area of clearing produced thereby is a function of enzyme concentration. Absolute molar rates for unknown samples may be calculated if standards of known activity are used concurrently. The precision of the simplified assay compared favorably with a method based on titrimetric determination of the rate of free fatty acid release. A modified assay has been used to assess the potency of lipoproteins in lipoprotein lipase activation.

Animals↗
PubMedDate not supplied

Abnormal post-heparin lipolytic activity in obesity. A preliminary note.

Published data have suggested that hypertriglyceridemia in obesity may result from the combination of hepatic overproduction and diminished removal of triglyceride-rich lipoproteins. Diminished catabolism might be expected if tissue lipoprotein lipase activity were decreased, a finding which has been reported in biopsies of adipose tissue from obese subjects. Abnormalities in heparin-released triglyceride lipase activity (PHLA) in obesity have not been reported, however. We have examined the possibility that methods for the measurement of PHLA might have failed to reveal such a defect because of the disproportionality between plasma volume and increasing body mass in obesity. Since it is usual to administer heparin on the basis of body weight, higher plasma heparin levels would be achieved in obese individuals. We performed standard PHLA assays in lean and obese volunteers. In the obese, heparin levels were consistently higher than in lean individuals although PHLA values were similar in both. Thus, PHLA in obesity appeared to be inappropriate for the heparin levels attained in plasma. Pharmacokinetic studies suggest that a decrease in PHLA available for release by heparin rather than heparin insensitivity underlies this phenomenon.

Adult↗
PubMedDate not supplied

Implications of pregnancy for residents and their training programs.

This study investigated the implications of pregnancy on residents and their training programs and how programs have planned for pregnancy disruptions compared to other employers. We received questionnaires from 236 male and female residents and their families who had experienced at least one pregnancy during their training. Results for female residents were compared with working spouses of male residents. Approximately half of the female residents reported that their programs had formal leave policies compared to 70% of the working spouses. The average amount of leave taken by residents was considerably less than that taken by the spouse group. For both groups, 35% of all pregnancies were unplanned; 19% of these without benefit of birth control. Approximately 30% of both groups said they should have timed their pregnancies differently. Female residents were more likely to perceive their pregnancies as a stressful time. Despite this greater stress, female residents were equally as unlikely as spouses of male residents to miss work for pregnancy-related causes. This study supports the need for better planning for pregnancy during residency training.

Adult↗