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Biomedical subjects

M Keeney

Publications and source records attributed to M Keeney.

At least 55 records · Page 3Linked to original sources
PubMed1992

Lactation curves and effect of pup removal on milk fat of C57Bl/6J mice fed different diet fats.

Groups of C57Bl/6J mice, fed either a cis (C-Diet) or trans diet (T-Diet) were milked without preconditioning at 6, 8, 10 and 12 days postpartum. On day 10, groups of mice were also milked 4, 6 and 18 h after separation of the pups. Except for the 18-h separation, all T-Diet fed animals produced milk of lower fat content than did the C-Diet animals (P < 0.001) throughout the lactation period measured. In the C-Diet mice, the 6-h separation period resulted in a decrease (P < or = 0.03) in fat, but the diet-depressed milk fat of T-Diet animals was not decreased further until the 18-h separation period. Milk volume increased as lactation progressed and was greatly increased as a result of preconditioning (P < or = 0.001), even at 4 h of separation when fat was not reduced, and was always greater for T-Diet animals. Within diet groups, fatty acid composition was similar throughout the lactation period studied and was not affected by preconditioning except in the 18-h separation period, when de novo fatty acids were significantly reduced (P < or = 0.05). The data are consistent with the hypothesis that preconditioning results in lowered milk fat values and that preconditioning techniques can explain discrepancies in literature values for murine milk fat.

Animals↗
PubMed1991

Flow cytometric reticulocyte analysis using thiazole orange; clinical experience and technical limitations.

Flow cytometric (FCM) reticulocyte analysis using thiazole orange (TO) is becoming an increasingly popular method for routine quantification of reticulocytes. The methodology is accurate, cost-effective and shows a high correlation with manual techniques. We describe our experience with the clinical application of FCM reticulocyte analysis in a general hospital setting over a 20-month period with special emphasis on technical limitations.

Antineoplastic Agents↗
PubMed1990

The prognostic significance of tumor ploidy and pathology in adenocarcinoma of the esophagogastric junction.

Tumor DNA content has been advocated to be an important prognostic indicator in human malignancies. Paraffin-embedded specimens of 75 resected adenocarcinomas (AC) of the esophagogastric junction were studied by flow cytometric DNA analysis to determine whether tumor ploidy was a significant prognostic variable independent of stage and histologic grade of the tumor. Eighty-one percent of the tumors were aneuploid. More patients with aneuploid tumors had lymph node metastases than patients with diploid tumors (P = 0.007). Patients with aneuploid tumors had poorer 18-month disease-free and overall survival than patients with diploid tumors. Cox regression analysis demonstrated that the most important prognostic variables for predicting overall survival were lymph node status, depth of wall invasion, and tumor differentiation. Tumor ploidy was not an independent prognostic variable in predicting recurrent disease or death from AC of the esophagogastric junction. Tumor DNA content is valuable, however, as a marker for patients at increased risk of lymph node metastases, early recurrence, and poorer survival.

Adenocarcinoma↗
PubMed1990

Isomeric trans fatty acids in the U.S. diet.

Since actual consumption data for trans fatty acid (FA) intakes for the U.S. population do not exist, estimates of trans fatty acids (FAs) available in the U.S. food supply have been calculated from U.S. Department of Agriculture-Economic Research Service (USDA-ERS) fats and oils production figures and food disappearance data for fats and oils. Based on weighted averages for the trans levels in each fats and oils category, these estimates of trans FAs available in the U.S. food supply range from 12.5 to 15.2 g/person/day (average 13.3 +/- 1.1 g/person/day). Estimates of trans FA consumption have been calculated; these estimates predict a wide range from 1.6 to 38.7 g/person/day. These calculations are based on published estimates of trans FAs available in the total fat of 5-15%, and the total fat intake (range 31-258 g/person/day) of a representative sample of adults (ages 20-59) as determined by the Lipid Research Clinics (LRC). Using an equation based on a relationship between trans FAs in adipose tissue and dietary fat, an intake range of 0.7-28.7 g/person/day trans FAs for the same LRC fat consumption data can be predicted. Adipose tissue isomer profiles that indicate 90-95% of the trans FAs in the tissues comes from partially hydrogenated vegetable fats and oils allow us to predict a dietary intake range from 11.1 to 27.6 g/person/day trans FAs. The significance of these estimates to nutrition policy is discussed.

Dietary Fats↗
PubMed1990

Milk fat depression in C57Bl/6J mice consuming partially hydrogenated fat.

Mice of the C57Bl/6J strain were maintained on diets in which the unsaturated fatty acids were all cis fatty acids (CFA) or a mixture of CFA and trans fatty acids (TFA). The fats used were mixtures of corn oil, olive oil, cocoa butter, margarine and shortening blended to yield similar fatty acid compositions, except for the ratio of the CFA to TFA and the percentage of linoleic acid (EFA). Regardless of the level of fat (20 or 40 energy %) or the level of EFA (2 to 12 energy %), diets with TFA decreased the percentage of fat in mouse milk. When lactating females raised on the CFA diets were crossed to the TFA diets, TFA appeared in the milk at 12 h postcross, and within 4 d postcross the percent of milk fat was decreased to levels similar to that of nursing females raised continuously on the TFA diets. Conversely, lactating females crossed from TFA to CFA diets produced milk with percentage fat values and fatty acid compositions that approached those seen in nursing females fed the CFA diets continuously. The possible involvement of TFA in the classical milk fat depression phenomenon in ruminants and its potential relevance in human lactation are discussed.

Animals↗
PubMed1987

Analysis of positional isomers of monounsaturated fatty acids by high performance liquid chromatography of 2,4-dinitrophenylhydrazones of reduced ozonides.

A method is described for quantifying the positional isomers in monounsaturated fatty acid methyl ester (FAME) fractions. The procedure involves the preparation of 2,4-dinitrophenylhydrazones (DNPH) of the fragments generated during reductive ozonolysis of FAME, class isolation of the aldehyde and aldehyde ester DNPH, and separation of the aldehyde ester derivatives by high performance liquid chromatography (HPLC). The high extinction coefficient of the DNPH provides for a sensitive assay which is linear for a large range of components over a concentration range of 0.075-5 nmol/component, and the stability of the DNPH permits the independent analysis of the aldehyde and aldehyde ester fragments generated during reductive ozonolysis. The reductive ozonolysis-DNPH-HPLC method developed is as sensitive, reproducible, and accurate as reductive ozonolysis-gas-liquid chromatography and does not suffer from some of the drawbacks of the classical procedure.

Chromatography, High Pressure Liquid↗
PubMed1983

Serum uric acid, inorganic phosphorus, and glutamic-oxalacetic transaminase and blood pressure in carbohydrate-sensitive adults consuming three different levels of sucrose.

12 men and 12 women, classified as carbohydrate-sensitive on the basis of an exaggerated insulin response to a sucrose load, consumed diets containing either 5, 18, or 33% sucrose in a crossover design. The diets simulated the average American diet and consisted of identical natural and processed foods with the exception of a patty. The patty provided the experimental levels of sucrose; the difference was made up by starch. Each level of sucrose was consumed for a 6-week period. Subject body weights were maintained. Fasting serum uric acid and inorganic phosphorus increased as the level of dietary sucrose increased. Diastolic blood pressure was significantly higher when subjects were on the 33% sucrose diet as compared to the 5 and 18% diets. Serum glutamic-oxalacetic transaminase was not affected by diet. In tolerance tests after a sucrose load (2 g/kg body weight), the uric acid response was higher after the 18 and 33% sucrose diets than after the 5% sucrose diet. Serum inorganic phosphorus, which increased significantly with each level of dietary sucrose, decreased following the sucrose load. These results indicate that carbohydrate-sensitive individuals may be affected adversely by the level of sucrose commonly found in the Westernized diet. Since elevated serum uric acid and blood pressure have been identified as risk factors in degenerative diseases, this study suggests that carbohydrate-sensitive individuals should limit their sucrose consumption.

Adult↗
PubMed1981

Serum insulin and glucose in hyperinsulinemic subjects fed three different levels of sucrose.

Twenty-four adult men and women, classified as carbohydrate-sensitive on the basis of an exaggerated insulin response to a sucrose load, consumed diets containing 5, 18, and 33% of calories as sucrose for 6 wk each in a cross-over design. The diets contained identical natural and processed foods except for a patty containing 2, 15, or 30% of the calories as sucrose at the expense of wheat starch. Carbohydrate, fat, and protein provided 44, 42, and 14% of the calories, respectively. Of total calories, 25% were consumed at breakfast and 75% at dinner. Initial body weights of the subjects were essentially maintained. Fasting serum insulin levels increased with the sucrose content of the diet and were significantly higher in men than in women. Mean fasting glucose was significantly higher on either 18 or 33% sucrose than on 5% sucrose. The sucrose content of the diet did not affect fasting serum glucagon. When compared to the insulin response to a sucrose load (2 g/kg body weight) after consuming the 5% sucrose diet, serum insulin was significantly higher at 1 h after the 18% sucrose diet and at 0.5, 1, 2, and 3 h after the 33% sucrose diet. Except after 2 h, the glucose response was significantly greater after the 18 and 33% sucrose diets than after the 5% sucrose diet. These results indicate that sucrose intake by carbohydrate-sensitive individuals, even at levels approximating the average United States intake, can produce undesirable changes in several parameters associated with glucose tolerance.

Blood Glucose↗
PubMed1981

Comments on the effects of dietary trans-fatty acids in humans.

Papers presented at this Workshop report clues which suggest further research on the role of dietary fat in the etiology of some forms of cancer. The research has not yet yielded information which can be used to make responsible dietary recommendations to the public. The suggestion that dietary animal fats are associated with "fat-related" cancers is not well documented. Virtually all of the increase in fat consumption in the United States during the 20th century has been due to vegetable fats. Many of these vegetable oils are partially hydrogenated, resulting in the accumulation of significant amounts of trans-fatty acids in such products as margarines and shortenings. It is suggested that more research attention should be given to the effects of dietary trans-fatty acids on animal physiology.

Diet↗
PubMed1978

Dietary fat and cancer trends--a critique.

Recent speculation concerning the relationship of dietary fat and cancer causation is challenged. Correlations between increase in per capita dietary fat intake and cancer mortality over a 60-year period show significant positive correlations for total fat and vegetable fat, and negative or no correlation for animal fat. The significant positive correlation for vegetable fat could not always be explained by the effects of total unsaturated components; individual unsaturated components, such as oleic or linoleic fatty acids; or the saturated component; but could be explained by the trans fatty acid component.

Animals↗
PubMed1973

Sodium and other inorganic growth requirements of bacteroides amylophilus.

Bacteroides amylophilus has growth requirements for Na(+), PO(4) (3-), K(+), and small quantities of Mg(2+). No requirement could be shown for Ca(2+) in media previously found growth-yield-limiting for Bacteroides succinogenes. Deletion of Co(2+), Mn(2+), Cl(-), or SO(4) (2-) did not affect growth. Quantitative studies indicate that Na(+), K(+), and PO(4) (3-) have differing effects on the growth of B. amylophilus. A concentration of sodium and potassium ions affects both growth rate and growth yield, whereas a phosphate concentration markedly affects growth yield, but affects growth rate only slightly, if at all. The sodium requirement of B. amylophilus is absolute. It cannot be replaced by K(+), Li(+), Rb(+), or Cs(+). The latter three monovalent cations are toxic to B. amylophilus if supplied to the organism at Na(+)-replacing concentrations. K(+) is inactive at similar concentrations. The K(+) requirement of B. amylophilus may be satisfied by Rb(+). The concentration of Na(+) required by B. amylophilus for abundant growth suggests that B. amylophilus should be considered a slightly halophilic organism. The results suggest that Na(+) may be a more frequent requirement among terrestial bacteria obtained from relatively low-salt environments than has been previously believed.

Animals↗
PubMed1969

Effects of carbon dioxide on growth and maltose fermentation by Bacteroides amylophilus.

The requirement of carbon dioxide for growth of Bacteroides amylophilus is quantitatively similar to that of certain other rumen bacteria. Carbon dioxide could be replaced by bicarbonate, but not by formate or certain amino acids. Label from (14)CO(2) was incorporated into the succinate produced during maltose fermentation by B. amylophilus, and during glucose fermentation by B. ruminicola, and during cellobiose fermentation by B. succinogenes. All of the incorporated label could be associated with the carboxyl function of the molecule. The depression in radioactivity per micromole of carbon in the succinate formed from the fermentation of uniformly labeled (14)C-maltose by B. amylophilus was greater than would be expected if all of the succinate formed was produced via a direct CO(2) fixation pathway(s) involving phosphoenolpyruvate or pyruvate; the radioactivity per micromole of carbon suggests that as much as 60% of the total succinate results from a pathway(s) involving direct CO(2) fixation. Maltose fermentation by B. amylophilus was dependent upon CO(2) concentration, but CO(2) concentration could not be shown to influence either the fermentation end-product ratios or the proportion of total succinate formed attributable to CO(2) fixation.

Amino Acids↗