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Biomedical subjects

E J Calabrese

Publications and source records attributed to E J Calabrese.

At least 127 records · Page 7Linked to original sources
PubMed1986

Predictive models for human glucose-6-phosphate dehydrogenase deficiency.

The present paper has discussed available test systems for determination of the response of G-6-PD-deficient human erythrocytes to environmental agents. The limitations and advantages of each model have been examined, and the results of research using each model have been presented. The future development of suitable animal models or in vitro test systems may rely on advances in fields such as genetics and biochemistry. Genetic engineering may allow researchers to develop cells with a genetic deficiency of G-6-PD. These deficient cells could then be used to simulate human G-6-PD-deficient erythrocyte responses to various agents. Advances in biochemistry, in areas such as metabolism and enzymology, may also have an impact on future test systems. Due to the fact that present model systems are limited and their predictions often unreliable, the establishment of safe environmental health standards will depend upon advances in modern science and the converging of developments from various disciplines.

Animals↗
PubMed1985

Ozone-induced inhibition of theophylline elimination in rabbits: effect of age and sex.

The effect of age and sex on the elimination of theophylline in New Zealand White rabbits was investigated following exposure to 0.3 ppm of ozone (O3) for 3.75 hr/day over 5 consecutive days. Animals were given air alone 5 to 7 days before and after the 5 days of O3 exposure. The elimination half-life of theophylline was significantly (p = 0.004) prolonged on Days 1 and 5 of O3 exposure in the rabbits greater than 2 years old, with no effect being seen in those 3 to 4 months old. No O3-induced change was seen in the apparent volume of distribution to account for the observed change in theophylline elimination half-life. The female rabbit in particular demonstrated this age-related effect; while in the male, variability prevented the observed difference from reaching significance. The results indicated inhibition of theophylline elimination by O3 in the rabbit depends on age and sex.

Aging↗
PubMed1985

Uncertainty factors and interindividual variation.

Human variation in response to environmental agents appears often greater than a factor of 10, sometimes even up to several orders of magnitude. However, the vast majority of people studied to date respond within a factor of 10. The implications of these findings for the current use of uncertainty factors in regulatory toxicology is discussed.

Acetylation↗
PubMed1985

The Massachusetts Blood Pressure Study, Part 1. Elevated levels of sodium in drinking water and blood pressure levels in children.

Continuing epidemiologic studies at the University of Massachusetts have examined the hypothesis that elevated levels of sodium (Na) in drinking water contribute to elevations of blood pressure (BP). Comparing tenth graders from a town with 107 mg Na/L in the drinking water to those from a town with 8 mg Na/L revealed statistically significant and medically important higher BP distributions among the high Na town students relative to their low Na town peers for both systolic and diastolic BP in both boys and girls. The differences were upheld when potentially confounding factors, including dietary Na intake and other water factors occurring differentially in the two water supplies, were controlled in the analysis. A replication study among third graders in the same communities showed similar results.

Adolescent↗
PubMed1985

The Massachusetts Blood Pressure Study, Part 2. Modestly elevated levels of sodium in drinking water and blood pressure levels in high school students.

The blood pressure (BP) of tenth grade students from a town with 42 mg Na/L in drinking water was compared to that of comparable tenth grade students in a geographically contiguous community with 6 mg Na/L. No statistically significant difference occurred in mean BP between the two communities for males and females for diastolic BP and male systolic BP. However, the low sodium community females displayed a significantly higher BP (p less than 0.05) of 1.6 mmHg. Analysis of covariance for potentially confounding variables did not significantly alter the initial findings. In summary, an average of 36 mg Na/L higher Na levels in the drinking water was not associated with an increase in BP levels in tenth grade students.

Adolescent↗
PubMed1985

The Massachusetts Blood Pressure Study, Part 3. Experimental reduction of sodium in drinking water: effects on blood pressure.

An experimental bottled water study assessed the effect on blood pressure of lowering Na concentration in the water of some of the high sodium community fourth graders. For three months, trios of children matched by sex, school, and baseline BP each used different water for all cooking and drinking purposes, with BP monitored bi-weekly. Pupils were randomly allocated to the three water conditions: high sodium water bottled from their own community distribution system, low sodium water bottled from the distribution system of the comparison community with sodium added to the level of the high sodium community water and low sodium water bottled from the distribution system of the low sodium community but with no sodium added. The results indicate that BP levels among the girls but not boys on the low sodium water exhibited marked decreases in BP over the test period when compared to the other two groups.

Adolescent↗
PubMed1985

The Massachusetts Blood Pressure Study, Part 4. Modest sodium supplementation and blood pressure change in boarding school girls.

Based upon the results of the earlier work, a sodium supplement study was designed and carried out at a private boarding school. Two hundred and sixteen 9th-12th grade girls were randomly assigned to one of three groups while continuing to eat their regular meals at the dining commons. All participating students took two capsules, under supervision, both mid-morning and subsequent to the evening meal. One group received placebos at both times, one group received 2 G of salt in the morning and a placebo in the evening, and the final group received a placebo in the morning and 2 G of salt in the evening. One week of baseline data and eight weeks of follow-up data were collected twice weekly for BP, pulse, 24-hour urine specimen, and stress of daily events. Repeated measures analysis of variance failed to detect a significant difference in change in systolic and diastolic BP between groups. Extensive analysis of other variables did not uncover any negative confounding or interaction. Drop out rates were very low and compliance rates very high. The urinalysis clearly demonstrated that the Na excretion in the two supplement groups was similar and significantly elevated over the placebo group, thus documenting the high Na supplement compliance rates.

Adolescent↗
PubMed1985

Health implications of a 5 mm Hg increase in blood pressure.

The health implications of a mean increase in blood pressure on the order of 5 mm Hg among young persons are explored primarily from a public health point of view. After an overview of the epidemiologic behavior of human blood pressure is provided, the phenomenon of "tracking" of blood pressure is examined as is the possible relationship between the rate of blood pressure change over time and the initial value. In the last part of the paper, the community benefits of lowering the average blood pressure 5 mm Hg (in terms of number of heart attacks prevented) are estimated under several simplifying assumptions.

Adolescent↗
PubMed1985

Does exposure to environmental pollutants increase the need for vitamin C?

Using ascorbic acid as a model, this paper proposes that the concept of the RDA should be broadened to take into account the effects of ubiquitous pollutants on human health, a factor not specifically incorporated in RDA derivations. It is now widely accepted that ascorbic acid nutritional status markedly affects the toxicity and/or carcinogenicity of greater than 50 pollutants, many of which are ubiquitous in the air, water, and food environments. At the present time, the data do not warrant changing the ascorbic acid RDA in light of the knowledge of pollutant interactions.

Air Pollutants, Occupational↗
PubMed1984

The effects of di- and trichloroacetic acid on sheep erythrocytes: an animal model with a glucose-6-phosphate dehydrogenase deficiency.

Erythrocytes of Dorset sheep, an animal model with an erythrocyte glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, responded in a dose-dependent manner to the oxidant stress of di- and trichloroacetic acids (DCA and TCA) as measured by increases in methemoglobin (METHB) and decreases in glutathione (GSH). Given the fact that TCA and DCA are now being found in community drinking water supplies at levels greater than 100 micrograms/liter, there is a need to further investigate their effects on biological systems, including those with a compromised ability to deal with oxidant stress (e.g., G-6-PD-deficient erythrocytes).

Acetates↗
PubMed1984

Does chloroform exposure while showering pose a serious public health concern?

The problem of organic chemicals in drinking water has been well known since 1974-1975 when the National Organics Reconnaissance Survey (NORS) and the National Organics Monitoring Survey (NOMS) showed that drinking water contaminated by organics could be found throughout the nation. Of special concern are the trihalomethanes (THMs) one of which, chloroform, is a suspected human carcinogen, and has been proven to be carcinogenic in test animals. In addition to chloroform exposure from drinking water, inhalation of chloroform from air while showering may constitute an additional source of exposure. Since the EPA has not included exposure to airborne chloroform in their risk-assessment calculations, the actual cancer risk to the population due to chloroform in drinking water may be significantly higher than the EPA estimated. It is suggested that a major research effort be directed at the determination of airborne chloroform levels in the domestic shower environment. Effort should also be made to determine what variables affect the magnitude of the chloroform levels if present. Once these variables are known it may be possible to educate the public about the potential hazard and ways to eliminate or reduce it.

Air Pollutants↗
PubMed1984

Environmental validation of the homocystine theory of arteriosclerosis.

It has been proposed that elevated concentrations of homocystine in vascular tissue could cause arterial damage leading to arteriosclerosis. This theory is indirectly supported by research in the area of environmental toxicology, which has revealed that carbon monoxide and carbon disulfide, agents whose prolonged exposure is known to result in the development of arteriosclerotic changes, induced vitamin B6 deficiency states which predictably lead to a homocystinuria-like state. Such information provides strong indirect support of the controversial homocystine theory of arteriosclerosis.

Adult↗