Minerals and blood pressure

The mineral elements sodium, potassium, calcium and magnesium play a central role in the normal regulation of blood pressure. In particular, these mineral elements have important interrelationships in the control of arterial resistance. These elements, especially sodium and potassium, also regulate the fluid balance of the body and, hence, influence the cardiac output. Evidence shows that the present levels of intake of mineral elements are not optimum for maintaining normal blood pressure but predispose to the development of arterial hypertension. Research results suggest that without sodium chloride (common salt) and other sodium compounds being added to the diet arterial hypertension would be virtually non existent. Moreover, blood pressure would not rise with age. In communities with a high consumption of added sodium, a high intake of potassium and, possibly, magnesium seem to protect against the development of arterial hypertension and the rise of blood pressure with age. A marked reduction of sodium intake is effective in treating even severe hypertension. A moderate restriction of sodium intake or an increase in potassium intake exert remarkable antihypertensive effects, at least in some hypertensive patients. Magnesium and possibly also calcium supplements may be effective in reducing blood pressure in some hypertensives. In hypertensive patients treated with drugs sodium restriction and potassium and magnesium supplementation enhance the therapeutic effect, reduce the number and dosage, and lessen the adverse effects of prescribed antihypertensive drugs. Hence, a fall in sodium consumption and increases in potassium and magnesium consumption are useful in preventing and treating arterial hypertension.     

Screening recommendations for the elderly.

BACKGROUND. Studies have documented the potential contributions of preventive health care programs. Yet little is known about which screening tests should be included in public health programs for older persons. This study offers recommendations regarding these tests. METHODS. The recommendations come from synthesizing the findings of the US Preventive Services Task Force, the literature, and the consensus of experts in geriatrics, gerontology, and health policy research. The literature was evaluated to identify methodologically sound studies of the prevalence of selected disorders and benefits and availability of screening procedures for those disorders. Experts from various fields specializing in the care of the elderly formed panels to assist in evaluating the literature and providing further information from gerontological and public health perspectives. RESULTS. We recommend vision testing for refractive error; inspection of the skin surface for fungal infection and skin cancer, drug eruptions, and xerosis; a history for symptoms of xerosis; audiometric testing for presbycusis; surveys for hearing loss; otoscopic inspection for cerumen impaction; dental examination for caries; measurement of blood pressure for hypertension; and breast examination and mammography for cancer. CONCLUSIONS. Our study suggests that these screening procedures are useful for public health screening programs. More information is needed on the effects of screening services on the health and functioning of older persons.     

Involving patients in do not resuscitate (DNR) decisions: an old issue raising its ugly head.

A recent paper in this journal (1) suggests that involving terminally ill patients in choices concerned with Cardio-Pulmonary Resuscitation (CPR) produces 'psychological pain' and therefore is ill-advised. Such a claim rests on anecdotal observations made by the authors. In this paper I suggest that drawing conclusions in ethics, no less than in science, requires a rigorous framework and cannot be relegated to personal observation of a few cases. The paper concludes by suggesting that patients, if we acknowledge their valid interest in making their own choices, must themselves be allowed to make a prior choice about choosing. Those who may not wish to choose may properly be relieved of this burden and may allow another to choose for them. Routinely allowing others to make choices for competent adults, however, is likely to decrease communication with the dying patient and to introduce an atmosphere of suspicion and fear and to exclude the competent patient from his/her rightful place in the community.     

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.