Radium-226 dose to a boy from playing on mill tailings

Two boys born in September 1949 played on uranium mill tailings from about ages 8 to 12. One of these boys was diagnosed as having leukemia at age 15.5. The 226Ra body burden of the survivor was measured at age 38. The whole-body 226Ra content measured by counting in vivo was 0 +/- 17 Bq and independently by Rn breath analysis as 4.3 +/- 2.1 Bq. At the same time, a control subject with no known exposure to 226Ra, matched in age, height, and weight, was also measured. The whole-body content was estimated as 4 +/- 15 Bq and independently by Rn breath analysis as 5.5 +/- 3.7 Bq. The body burden of the control subject was not significantly different from that of the exposed person. The radiation dose to the marrow-free skeleton assuming a constant 226Ra:Ca ratio since birth was 0.49 and 1.33 mGy at ages 14 and 38, respectively. The radiation dose to the marrow-free skeleton assuming 226Ra intake only between ages 8 to 12 was 1.4 and 2.8 mGy at ages 14 and 38, respectively. The best estimate is the mean of these two estimates: 0.9 and 2.1 mGy at ages 14 and 38, respectively. The alpha-particle dose to the red marrow from 226Ra and its decay products was 0.05 mGy at age 14 and 0.10 mGy at age 38. Since no excess was found for the radium dial painters whose doses were much higher, the induction of leukemia by doses of this magnitude would seem quite unlikely.     

Copper uptake and transfer to the mouse fetus during pregnancy

Accumulation of 64Cu in the 14-d mouse fetus was measured following intravenous injection of the dam with 64CuHis2. Concentration of 64Cu in the placenta increased rapidly over the first 4 h, thereafter remaining constant. Transfer to the fetus was linear over 48 h with little evidence of storage in the liver. Maternal serum levels decreased initially, concurrently with increased 64Cu levels in the maternal liver, but did not subsequently increase. Immediately following injection, as much as 40% of the radioactivity was in the nonalbumin fraction, and approximately 37% of that fraction (18% of total) was greater than 30,000 molecular weight. After 24 h, up to 60% of the 64Cu was still found in the albumin peak. The data suggest that the fetus can obtain its Cu from maternal ceruloplasmin but does not exclude the possibility that transfer occurs from the exchangeable (albumin/amino acid) Cu pool of the maternal plasma. In a second experiment, mice at different stages of gestation were injected with 64Cu and killed 4 h later. Total Cu levels and 64Cu uptake into the maternal tissues or into the placenta did not change with increasing gestation. Both total Cu and 64Cu uptake in the fetus and fetal liver increased to a maximum on d 16. Levels in the liver decreased thereafter to term, whereas levels in the rest of the fetus remained approximately constant. The pattern was similar whether the results were expressed per organ or per gram of fresh weight.(ABSTRACT TRUNCATED AT 250 WORDS)     

Weight loss in women participating in a randomized trial of low-fat diets

We examined weight changes over 1 and 2 y in 303 women enrolled in a low-fat dietary-intervention trial. Participants were randomly assigned to an intervention group that received intensive instruction in maintaining a low-fat diet or to a control group. After 1 y intervention-group women had decreased fat intake by 45.3 g (from 39.2% to 21.6% energy from fat) and weight by 3.1 kg (all P less than 0.0001); control-group women decreased fat intake by 8.8 g (from 38.9% to 37.3% energy from fat) and weight by 0.4 kg. In both univariate analyses and multivariate models, weight loss was more strongly associated with change in percent energy from fat than with change in total energy intake. These data, which are consistent with both epidemiologic and clinical studies, suggest that body adiposity is a function both of energy balance and the proportion of energy derived from fat.     

Adipose tissue fatty acid composition and its relations to diet and plasma lipid concentrations in hemodialysis patients

Adipose tissue fatty acid composition, serum lipid profile, and dietary intake of 37 patients on maintenance hemodialysis were studied. In August 1982, 1984, and 1986, analyses were carried out in 15 normotriglyceridemic (NTG) and 22 hypertriglyceridemic (HTG; type IV hyperlipidemia) patients. No correlations were found between dietary intake of polyunsaturated fatty acids (PUFAs), ratio of polyunsaturated to saturated fatty acids (P-S ratio), and carbohydrate content on the one hand and serum lipid concentrations on the other in the two groups. Adipose tissue linolenic acid correlated negatively with serum cholesterol in both groups. Strong correlations were found between dietary intake of PUFAs and adipose tissue linoleic acid content, between PUFAs and the double-bond index, between P-S ratio and adipose tissue linoleic acid content, and between P-S ratio and the double-bond index. No significant differences in dietary intake or adipose tissue fatty acid composition were observed between NTG and HTG patients. Thus, no evidence was found for exogenous dietary influences on serum lipid concentrations. The adipose tissue linoleic acid content did reflect the dietary intake of PUFAs.     

Nonabsorbable marker and single, random stool samples used for measuring intestinal absorption of macronutrients in infants and children

To measure intestinal absorption by using a single, random stool sample, polyethylene glycol (PEG), 1 g/d, and a constant diet were given to healthy infants, with a constant PEG-to-macronutrient ratio. After 10 d equilibration, apparent intestinal absorption of macronutrients was estimated from a standard 3-d metabolic balance and compared with that estimated by using the ratio of PEG to macronutrients in a single random sample of feces. Correlation coefficients for this comparison were 0.649, 0.715, and 0.924 for nitrogen, carbohydrate, and fat, respectively. Additionally, apparent intestinal absorptions estimated from two separate consecutive 3-d metabolic-balance studies were compared, showing correlation coefficients of 0.106, 0.653, and 0.463 for nitrogen, carbohydrate, and fat, respectively. The random sample-marker technique appears to be acceptable for measuring apparent absorption of macronutrients and is at least as accurate as a standard 3-d metabolic-balance study.     

Relative effects of diarrhea, fever, and dietary energy intake on weight gain in rural Bangladeshi children

Quantitative studies of morbidity, food intake, and somatic growth were done prospectively during 14 mo for 70 children aged 5-18 mo in two Bangladeshi villages. When random-effect regression models were used, monthly changes in weight were inversely related to proportions of days in the month with fever and diarrhea and positively related to energy intake per kilogram body weight. Interestingly, weight changes did not vary with age in this interval. Estimates indicate that increasing energy intakes to the recommended World Health Organization level would have a significantly greater effect on weight gain than would the elimination of diarrhea and fever. With energy at recommended intake and diarrhea and fever prevalence as found in US children, weight gain is predicted to be near that of the international reference population. Therefore, interventions aimed at improving dietary intake may be as important as infection-control programs for improving growth of children in poor developing nations.     

Ethics: responsible scientific conduct

Body composition and measures of obesity were evaluated in 59 subjects with myelomeningocele (MMC), aged 0.3-29 y, by anthropometry and measures of body cell mass (BCM) and intra- and extracellular water (ICW and ECW), derived from total body potassium and deuterium-isotope dilution; these results were compared with reference data. Body composition was normal in preambulatory children with MMC. Beyond ages 3-4 y there was significant depletion of BCM and total body water, with maldistribution of water (increased ECW and decreased ICW) and increased percentage body fat above that expected for age and sex. These findings were more pronounced in females and in those with high lesions, and were less pronounced in those who remained ambulatory. These changes may result in metabolic and nutritional maladaption during stress. The relation of BCM, total body water depletion and increased ECW to decreasing ambulatory activity suggests that early nutritional and mobility programs warrant further study.     

An experiment in medical education. A critical analysis using traditional criteria

In 1984, in addition to its standard traditional curriculum, Rush Medical College (Chicago, Ill) developed a Socratic problem-based method of teaching basic science material called the alternative curriculum. As part of an evaluation of this new curriculum, students in the two curricula were compared using three traditional measurements: (1) test scores from the National Board of Medical Examiners, Part I; (2) test scores from the National Board of Medical Examiners, Part II; and (3) performance on an oral examination. Alternative curriculum students did not differ significantly from their traditional curriculum classmates on National Board of Medical Examiners, Part I and Part II total scores, although their subset scores on Part I did tend to be lower, reaching significance in one subset area. Differences in performance favoring the traditional curriculum were primarily seen in the early years of the program. Alternative curriculum students in the class matriculated in 1987 scored significantly higher in three of five categories on the oral examination.