Gary F. Krause

Developmental toxicity of fumonisin in Syrian hamsters

The effects of fumonisin on development of Syrian hamster fetuses were studied using fumonisin B1 and B2 extracted fromFusarium moniliforme corn-culture and purified fumonisin B1. A significant increase in litters with fetal deaths occurred with the high doses of purified (18 mg FB1/kg) and culture-extracted (18 mg FB1 plus 4.5 mg FB2) fumonisin. It is concluded that prenatal exposure to fumonisin on days 8 and 9 of gestation is detrimental to fetal hamster survivability but does not induce clinical maternal intoxication at these doses. Equivalent doses of fumonisin B1, whether from culture-extract or pure solution produced similar results.

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.

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.

Comparison of body composition measured by total body potassium and infrared interactance.

OBJECTIVE The purpose of this study was to find how closely a near infrared instrument (IRI), Futrex 5000, would compare to whole body counting (WBC) of potassium-40 (40K) in assessing body composition. DESIGN We measured lean body mass (LBM) and percent total body fat (PCF) in 177 males and 27 females by total body potassium (TBK) and by infrared interactance (IRI). TBK was assessed by 2 pi whole body counter (WBC) and IRI by Futrex (F) instrument. These subjects were measured for TBK and for IRI within 1 week of each other. RESULT A large mean difference (p < or = 0.001) was found between the results using the two instruments: IRI data for LBM were higher and PCF lower compared to TBK. CONCLUSION As shown by repeated TBK measurements over a 22-year period in these same volunteers, this technique is reliable. The IRI assessments did not come to a close fit with TBK.

Reproductive Characteristics in Sinclair Miniature Swine

Three hundred seventy one litter records collected between 1985 and 1993 from 156 Sinclair(S-1) miniature sows, a Hormel derived strain of miniature swine, were analyzed retrospectively and compared with previously published records representing 1950 to 1952 and 1963 to 1965. Effects of several variables, such as season and month of parturition, age of sow, parity and litter size, on reproductive parameters of Sinclair miniature swine were evaluated. Preovulatory follicular and ovulation rates were evaluated in 230 virgin Sinclair miniature gilts. Means ± SEM for litter size, number of liveborn, number of stillborn and litter size at weaning of Sinclair(S-1) miniature swine were 7.20 ±0.12, 6.57 ±0.12, 0.63 ± 0.06 and 5.75 ±0.12 piglets, respectively. From a total of 2436 liveborn piglets, 2133 (87.6%) were weaned. Litter size at birth was similar to that reported previously for this strain of swine; whereas, mean litter size at weaning increased from 4.7 piglets during 1963 to 1965 to 5.8 piglets in our study. Average birth weight decreased from 0.90 kg in 1950 to 1952 and 0.72 kg in 1963 to 1965 to 0.59 kg in our study. Reproductive variables that affected miniswine reproduction included month of parturition, age of sow, parity and litter size. Primiparous sows had the smallest litter size and lowest number of weaned piglets. Sows during their second and third parity or sows between 2 and 4 yr old had the best reproductive performances. Litter size and number of stillborn increased with parity and age of sow resulting in fewer piglets weaned in older sows. Litter size had a curvilinear effect on preweaning mortality with the highest mortality occurring in small and large litters. The overall preovulatory follicular and ovulation rates were 9.0 ± 0.4 and 7.5 ± 0.1, respectively. At 10.7, 20.5 and 27.0 mo, ovulation rates were 6.6, 7.9 and 8.1, respectively. Ovulation rate paralled litter size. Overall, the production efficiency of Sinclair miniswine has been stable or improved since 1950, all reproductive variables evaluated, except season, were found to have an effect on miniswine reproduction; ovulation rate of Sinclair(S-l) miniature swine increases until about 20 mo of age and levels off thereafter; the small litter size of Sinclair(S-l) miniature swine is related to the low preovulatory follicular rate.

Amino acid requirements of guinea pigs using chemically defined diets

At the University of Missouri in Columbia we have been studying the nutritional requirements of the guinea pig using chemically defined diets. The purpose of this longterm study has been to enhance the value of this species as an animal model for human research. This presentation includes the results of over twenty experiments, 22 days in duration and involving over 1500 guinea pigs from 3–6 weeks of age.