Margaret A. Flynn

Total Body Potassium in Normal Children

Extract: Normative data for total body potassium on 462 children (232 boys and 230 girls) are presented. The regression of total body potassium on weight can be described as a straight line for males (grams K = 4.32 + 2.12 × weight) and two significantly different lines for females (grams K = −1.50 + 2.32 × weight for weight ≤ 30 kg, and grams K = 34.90 + 1.11 × weight for weight > 30 kg), with less potassium per kilogram for females weighing more than 30 kg. No sex-related difference is found between 12 and 30 kg. When the regression of total body potassium on height is examined, it is found that a logarithmic transformation of potassium values results in a similar pattern, with no sex-related differences between 100 and 135 cm and less potassium per centimeter in females over this height. For males, log K in grams = 1.761 + 0.0182 × cm of height; and for females, log Kin grams = 1.595 + 0.01942 × cm for height ≤ 135 cm, and log K in grams = 2.574 + 0.01215 × cm for height > 135 cm. The logarithmic transformation of K versus height is proposed as a standard because it reflects changes in slope associated with known physiologic and endocrinologic changes occurring with puberty and may be more sensitive than weight in predicting abnormal values in individual patients.Speculation: Since the regression of total body potassium on height appears to be a straight line common to both sexes 100–130 cm tall, with a diverging line indicating progressively less potassium per centimeter for females over 135 cm in height, these data were compared with available data for infants. The total body K values of infants between 50 and 80 cm in length appear to fall on a line with a steeper slope than values of children 100 to 135 cm tall. This observation suggests that, during the 1st year of life, increasing total body potassium per centimeter of length reflects maturation of body composition. Further extension of such observations to low birth weight infants might be expected to give information on their body composition.

Atherogenesis and the homocysteine-folate-cobalamin triad: do we need standardized analyses?

BACKGROUND Bioscientists, physicians and nutritionists are newly interested in the homocysteine-folate-cobalamin triad, in part because homocysteine may be important both in atherogenesis and thrombogenesis. Homocysteine imbalance may be an early marker for cobalamin disorders because cobalamin is a cofactor in remethylation of homocysteine to methionine. METHODS In 139 men and 32 women of similar mean age of 65 years, we measured markers which have been cited as risk for atherosclerosis: serum homocysteine, folate, total cobalamin, holotranscobalamin I and II, (TCI and TCII), total serum cholesterol (SCHOL), high density lipoprotein cholesterol (HDLC), triglycerides (STG) as well as red blood cell (RBC) folate, food records and body composition by whole body counting of potassium-forty (40K). RESULTS Statistical relationships among the data showed healthy women had lower mean serum homocysteine and their mean RBC folate and TCI and TCII were higher than men. Eighty-three subjects had TCII much lower than 60 pg/ml (subnormal), yet only 11 of these men and two women had total cobalamin < 200 pg/ml (abnormal). Fifty-two subjects with serum homocysteine greater than 17.5 nmol/ml had TCII less than 60 pg/ml, suggesting serum homocysteine may be a marker for early cobalamin negative balance. None of the subjects in the study had serum folate below abnormal values, i.e., less than 1.6 mg/ml. All subjects had RBC folate within normal range. Serum homocysteine showed inverse relationship with RBC folate and serum total cobalamin, TCI and TCII. CONCLUSIONS 1) importance of using serum holotranscobalamin TCI and TCII as markers of cobalamin deficiency, 2) necessity to use documented quantitative components of dietary intake if strong comparisons are to be made among quantitative values of serum or plasma homocysteine, folate, cobalamin, and nutrients in food intake.

Effects of cholesterol and fat modification of self-selected diets on serum lipids and their specific fatty acids in normocholesterolemic and hypercholesterolemic humans.

A 6-month crossover diet plan was employed to study the effects on human serum lipids of adding margarine or butter to otherwise self-selected diets that included two eggs daily. Two groups of subjects were studied: 51 free-living normocholesterolemic and 20 hypercholesterolemic (greater than 240 mg dl). Four-day diet records in each interval showed that subjects ate about 16% of total dietary fat as either butter or margarine. Blood samples taken every 6 weeks showed variable mean serum total cholesterol (SCHOL), high-density-lipoprotein cholesterol (HDL-C), and serum triglycerides (STG). The normocholesterolemic subjects who ate butter first had by 24 weeks mean SCHOL values equal to their entry values; those who ate margarine first had increased SCHOL values throughout the study. By the end of the study, the hypercholesterolemic subjects showed either no change or a slight decrease in both SCHOL and HDL-C values. Specific fatty acids were distributed differently in the serum fractions of triacylglycerol (TGFA), cholesteryl esters (CEFA), and phospholipids (PLFA). These distributions remained constant in both normocholesterolemic and hypercholesterolemic subjects regardless of the type and amount of fat consumed.

Gas-liquid chromatography of fecal neutral steroids☆

Abstract A method is described for the analysis of fecal neutral steroids with a dual-column gas-liquid chromatography (GLC) system. After saponification of the fecal slurry, the neutral steroids were extracted with hexane. The GLC separation of the compounds and quantitation were achieved by simultaneous injection of the derivatized and underivatized aliquots of the extract onto dual columns under identical conditions. The neutral steroids of interest were then identified by matching the retention times with those of known standards, and identification was confirmed by use of an interfaced GLC high-resolution mass spectrometry system. The detection limit was 0.003 mg of steroid/g of fecal slurry. The precision of the method is illustrated by a relative standard deviation of 2–10% and a recovery of neutral steroids from 73–96%. The method was applied to the determination of fecal neutral steroids in a “High protein diet in colon cancer study”. A considerably larger level of coprostanone than of coprostanol was observed. Data on neutral steroids in fecal samples from subjects on different diets are the subject of a separate publication.

A Longitudinal Study of Total Body Potassium in Normal Breastfed and Bottle-fed Infants

Extract: In a previous publication we predicted that growth as measured by 40K is best described by comparison of the semilog function of total body potassium (TBK) vs. length with a slope that differs in infants from that of children aged 3–18 years. Data for 84 infants having three or more measurements during the first year of life attest to this hypothesis, with a regression line for TBK and length: loge K, g = −;0.265 + 0.04112 length in centimeters.Speculation: The increasing rate of 40K accumulation between birth and the age of 1–2 years is compatible with the hypothesis that changes of body composition from that of the neonate to that of the adult is a steady process and that it is completed by the time the infant reaches a length of about 90 cm. This process is independent of sex and initial feeding within the conditions of this study. Further methodology refinements will be needed to determine the events occurring in low birth weight infants. The role of protein-calorie malnutrition in this process warrants study.

Eggs, Serum Lipids, Emotional Stress, and Blood Pressure in Medical Students

Emotional stress that occurred as a result of anticipation and participation in final exams did not change mean serum total cholesterol or high density lipoprotein cholesterol significantly in 26 male students who had eaten two eggs daily while maintaining a controlled diet for 12 wk. These same men continued to maintain a controlled diet but abstained from eating eggs for 12 wk which resulted in a statistically significant lower total cholesterol level at the end of 6 wk and on the day of final exams at the end of 12 wk. Mean values for high-density lipoprotein cholesterol in abstainers were significantly reduced at the end of 6 wk, but did not change further by 12 wk. Mean serum triglycerides values were variable. Blood pressures were not changed significantly.

Excretion of creatine and creatinine in feces of man.

Summary To examine the effects of a high beef diet on the bacterial flora and chemical composition of feces, 10 healthy human adults were fed four diets in succession for 1 month each: a control diet, meatless diet, high beef diet, and a repeat control diet. As a part of the larger study, creatine and creatinine were measured in the food consumed and in the feces excreted. Food creatine concentration was 5- to 12 -fold greater than creatinine; food creatine and creatinine were increased 4- and 10-fold, respectively, in the high beef diet compared with the control diets. Fecal creatine concentration was significantly elevated during the high beef diet (1.3-fold) over that in the control diets, whereas fecal creatinine excretion was elevated with only the meatless diet. Thus, creatinine and creatinine are present in human feces, and dietary creatine has an incomplete absorption during consumption of high beef diets.

Body Composition of Negro and White Children

In order to further assess nutritional status of Negro and white children aged 4 and 5 whose hematological and serum protein values were within normal range, body composition studies were done. Total body potassium was measured by whole body counting of gamma emissions of naturally occurring radioactive potassium (40K) with a 2π liquid scintillation counter. Standard anthropometric measurements were also performed. Results show no statistically significant difference in total body potassium in the two groups, regardless of sex. There are fat differences.

A longitudinal study of total body potassium in normal children.

Extract: Most investigators studying changes in body composition during growth agree to the desirability of having longitudinal data. A group of 110 boys and 126 girls, studied annually for 4-5 years with 880 measurements of total body K in a 2π liquid scintillation whole body counter, had total body K vs. height and total body K vs. weight data that fit previously described regression lines.Speculation: Given an adequate diet and environment, children increase their total body K in a predictable amount in reference to skeletal growth.

The Effect of Oral Contraceptives on Total-Body Potassium

In an effort to delineate one facel of the effects of synthetic progestogens on basic intracellular and extracellular electrolyte and fluid distribution, total body potassium was calculated, after background counts, from the average of three two- minute counts of γ-emissions of naturally occurring; radioactive potassium (40K) by whole-body counting of two groups of women in the child- bearing age. Group 1 consisted of 42 women taking a constant dosage over a period of nine months to four years of several combinations of synthetic; steroids comprising antifertility agents commercially available. Group 2 had 39 women not taking these drugs. Results showed that total- body potassium was the same in each group. Studies have shown body potassium to correlate well with intracellular water. One can speculate from this study that intracellular water appears to be unaffected by antifertility agents.