摘要:

Earlier studies have demonstrated that the Buffalo strain rat may have a defect in the process of methylneogenesis or lack the methyl-transfer enzyme system in the liver involved in methionine biosynthesis. The results of this study demonstrate that the enzyme systems responsible for methionine formation are present in the Buffalo rat and that these systems respond to ethanol feeding in a manner similar to that already shown in the Sprague-Dawley animal. These findings suggest that the previously described defect in methionine metabolism of the Buffalo rat may lie within the mechanism of methylneogenesis.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720356

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

The purpose of this study was to determine if supplementing total parenteral nutrition (TPN) with lipids or the branched chain amino acids (BCAA) leucine, isoleucine, and valine influences nitrogen balance in the injured patient. Four TPN study solutions were used, with each patient receiving two of the solutions for 4 days each. Group A received solutions consisting of 19% and 44% BCAA, with nonnitrogen calories supplied by 100% carbohydrate. Group B received a 7:3 carbohydrate-to-lipid ratio of nonnitrogen calories as a fuel source. Neither BCAA supplementation nor varying fuel substrates promoted a difference in nitrogen retention. The added cost of BCAA supplementation, along with the lack of an effect upon nitrogen accretion, indicates that greater benefits must be demonstrated before widespread use of BCAA supplementation can be recommended in the injured patient.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720357

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

There is growing recognition of the value of changing tissue fatty acid patterns in their own right as coronary risk factors. To examine the effects of a conventional nutritional program on plasma triglyceride (TG), cholesterol ester, and phospholipid fatty acid patterns, a group of 20 hyperlipidemic men and a control group (n = 6) of normolipidemic men were followed for 6 months. As an index of change in energy balance in the hyperlipidemic men, body mass index decreased from 26.5 to 24.4 kg m-2 (an 8% decrease) at 6 months. Saturated fat intake fell from 46.7 to 25.3 g/day (a 46% decrease). Dietary polyunsaturated:saturated fat ratio (P:S) rose from 0.38 and to 0.70 (an 84% increase) at the 6-month review. Ethanol intake fell from 18 to 15 g/day (a 17% decrease). Changes in plasma fatty acid (FA) patterns were found in TG, cholesterol ester, and phospholipid fractions at the 6-week to 3-month period, and these changes were maintained at 6 months. Of the factors possibly contributory to plasma FA pattern change in these men, dietary FA intake underwent the greatest percentage shift and therefore probably makes an important contribution to the change. It was of interest that fatty acid patterns in plasma neutral lipids (triglyceride, cholesterol ester, and phospholipid) significantly predicted body mass index and serum total cholesterol, triglyceride, and high-density-lipoprotein cholesterol.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720358

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

Hypomagnesemia is a common clinical finding in hospitalized patients and can cause hypocalcemia, cardiac arrhythmias, muscular weakness, and hypokalemia. Hypomagnesemia usually implies cellular magnesium (Mg) depletion, but stress and some clinical conditions which raise serum catecholamine concentrations may lower serum Mg (sMg) concentrations. To help investigate the mechanism and degree of the effect of catecholamines on sMg concentration, we gave intravenous epinephrine (0.1 microgram/kg/min) to 12 normal volunteers for 2 hours. The sMg concentration fell from 1.86 +/−0.04 mg/dl to 1.63 +/−0.05 mg/dl (mean +/−SEM, p less than 0.01). Pre-infusion intracellular free Mg (Mg++) in red blood cells (RBC) as measured by nuclear magnetic resonance spectrophotometry (NMR) was 171 +/−7.6 microM and did not differ significantly from post-infusion RBC Mg++, 186 +/−12.6 microM. Total blood mononuclear cell Mg content and urine Mg excretion also did not change. These data suggest that epinephrine has a small but significant effect on the lowering of sMg concentrations. Endogenous catecholamine release during stress or acute illness may therefore contribute to the hypomagnesemia seen in acutely ill patients. Our data also suggest that hypomagnesemia seen under conditions of acute stress may not always imply depleted tissue Mg stores. As no absolute change in cellular Mg or in urinary Mg excretion was demonstrated, acute intracellular shifts of Mg into blood cells and/or urinary Mg losses may not account for the hypomagnesemia. The prevalence and clinical consequences of stress hypomagnesemia require further investigation.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720359

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

Motor abnormalities have been observed in every species made vitamin B6 deficient, and have been detected and quantified early in vitamin B6 deficiency in young adult female Long-Evans rats with hind leg gait analysis. Our objective was to determine if hind leg gait analysis could be used to detect vitamin B6 deficiency in weanling (3 weeks) and aged (23 months) Fischer 344 male rats. Rats (n = 10 per group) were fed: the control diet ad libitum (AL-CON); the control diet devoid of added pyridoxine hydrochloride (DEF); or the control diet pair-fed to DEF (PF-CON). At 10 weeks, plasma pyridoxal phosphate concentration confirmed deficiency in both age groups. Gait abnormalities were detected in the absence of gross motor disturbances in both aged and weanling DEF rats at 2-3 weeks. Width of step was significantly reduced (16%, p less than 0.003) in DEF aged rats compared to AL- and PF-CON. This pattern of response was similar to that reported previously in young adult rats. In weanling rats, pair feeding alone reduced mean width of step (+/- SEM) by 25% compared to ad libitum feeding (2.7 +/−0.1 vs 3.6 +/−0.1 cm for PF- vs AL-CON, respectively, p less than 0.05). In DEF weanling rats, width (3.0 +/−0.1 cm) was increased compared to PF-CON (11%, p less than 0.05) but decreased compared to AL-CON (16%, p less than 0.05). Width of step was significantly altered early in B6 deficiency in rats of different ages and strains and in both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720360

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

To provide further insight into the possible role of selenium in cardiovascular disease, we examined the relationship between cardiovascular risk factors, some nutritional parameters, and short- and long-term selenium status. A total of 82 healthy Dutch volunteers, 59 men and 23 women, aged 40-75 years, were studied. Means and standard deviations of selenium parameters were: plasma selenium 106.4 +/−23.7 micrograms/L, erythrocyte selenium 0.59 +/−0.19 microgram/g Hb, toenail selenium 0.78 +/−0.17 ppm, and erythrocyte glutathione peroxidase activity 28.0 +/−8.1 U/g Hb. No association was found between selenium status and gender, age, serum total-, LDL-, and HDL-cholesterol, systolic and diastolic blood pressure, alcohol intake, and body mass index. A significantly lower plasma selenium level was observed among smokers compared to nonsmokers (101.0 micrograms/L, SE = 3.9 vs 112.0 micrograms/L, SE = 3.6, p = 0.04). A significant negative association was found between erythrocyte selenium and serum levels of vitamin A and ferritin. No relevant relationship was observed between selenium status and serum fatty acid composition, vitamin E, vitamin B6, and iron. Apart from an association between smoking and short-term selenium status, we found no indications that a possible effect of selenium on cardiovascular disease may operate through the known risk factors.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720361

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

The purpose of this research was to measure nutrient intake, body fat, [estimated from seven skinfolds: chest, axilla, triceps, subscapular, abdominal, suprailiac, and thigh (Jackson and Pollock, 1985)], total cholesterol (TC), HDL-cholesterol (HDL-C), HDL2-C, and HDL3-C of 19 male and 8 female bodybuilders competing in the National Physique Committee's USA Bodybuilding Championships (Raleigh, NC, April 1988). Casual blood samples and anthropometric data were collected 18 hours prior to competition, whereas 7-day diet records were completed 1 week prior to competition. Only 11 males and 2 females provided blood samples. Competitors were not tested for steroid use. These data are unique because the measurements were collected on site at the competition. Data are presented as means and standard deviations. Estimated body fat for males (6.0 +/−1.8%) and females (9.8 +/−1.5%) was quite low. Blood lipids (mg%) for males (TC = 187 +/−11, HDL-C = 37 +/−6, HDL2-C = 13 +/−4, and HDL3-C = 24 +/−4) were not indicative of increased coronary heart disease (CHD) risk. Data for the 2 females (TC = 190, 205; HDL-C = 56, 56; HDL2-C = 22, 8; and HDL3-C = 34, 48) could only be evaluated on an individual basis. Body fat was significantly correlated with HDL-C (r = 0.63; p = 0.04) and HDL3-C (r = 0.65; p = 0.03), but not TC nor HDL2-C. Of the dietary variables, only saturated fat was significantly correlated with HDL2-C (r = 0.60; p = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720362

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

Several studies suggest that beta-carotene reduces the risk of some cancers. Except for its function as an antioxidant, the effect of this vitamin on mammalian cells remains poorly defined. This study was performed to show whether beta-carotene treatment of murine B-16 melanoma cells in culture induces differentiation and alters the adenylate cyclase (AC) system. The AC system mediates the action of agents which regulate cell differentiation and transformation. Results showed that beta-carotene treatment for a period of 24 hours or more caused morphological differentiation without changing the level of melanin, and reduced basal and melanocyte-stimulated hormone (MSH)-, sodium fluoride (NaF)-, and forskolin-stimulated AC activity in vitro. Retinol, a metabolite of beta-carotene, inhibited growth without morphological differentiation and reduced basal and MSH- and NaF-stimulated AC activity. However, butylated hydroxyanisole, a lipid-soluble antioxidant, also reduced growth without morphological differentiation, but it failed to alter basal or MSH-stimulated AC activity. The present and previous studies show that the AC system represents a common site where some antitumor-promoting vitamins (beta-carotene, retinol, retinoic acid, and alpha-tocopheryl succinate) act.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720363

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

Several metabolic changes characteristic of the acute-phase response were examined in healthy men and women following a single 1 g dose of ascorbic acid. Utilizing a placebo-controlled, double-blind protocol, oral body temperatures were recorded in rested, fasted subjects (0900 hr) prior to the consumption of 1 g L-ascorbic acid or placebo (n = 10/group). Temperatures were recorded hourly for the next 8 hours, and again the next morning in the rested, fasted state (0900 hr). Blood samples, collected at 0, 4, and 24 hours post-dose, were analyzed for plasma ascorbate, iron, and zinc. Mean oral body temperature was significantly elevated 2 hours post-dose in the experimental subjects compared to controls (+0.7 degrees F, p = 0.03). In the vitamin-dosed subjects, mean plasma ascorbate rose 32% over the control value after 4 hours (1.11 +/−0.08 and 0.84 +/−0.06 mg/100 ml, ns). Serum iron levels were similar in the two groups at 0 and 4 hours post-dose, but at 24 hours post-dose mean serum iron of the vitamin-dosed subjects fell to 73% of that recorded for the control subjects (77 +/−8 and 105 +/−10 micrograms/100 ml, p = 0.04). Plasma zinc levels were similar for both groups at 0, 4, and 24 hours post-dose. These data indicate that ascorbate administration, at a level commonly supplemented in the US diet, elicits several host metabolic responses similar to those observed following exposure to infectious or inflammatory agents. These metabolic changes are most likely due to the reducing potential of the vitamin and may factor in the reported prophylactic success of vitamin C supplementation.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720364

出版商:Routledge    

年代:1990

数据来源: Taylor

摘要:

The effect of a moderate magnesium (Mg) deficiency on coronary arteries of 61 swine, fed various levels of vitamin D3, was studied by light and electron microscopy. The effect of subnormal Mg intake on vitamin D3-induced intimal lesions of the arteries showed a trend towards increased damage. The degree of cell degeneration and intimal thickening, which was induced by high vitamin D intakes, was as great in swine whose diet was low in Mg and moderately high in vitamin D as it was in those on twice as much vitamin D. Also, the degree of arterial calcification was intensified by inadequate Mg intake at the two higher vitamin D intakes. Present findings indicate that suboptimal dietary Mg, in combination with an excess of vitamin D, has an additive effect in the initiation of ultrastructural changes in the coronary arteries. Extension of the study is indicated to ascertain the extent to which further reduction of Mg intake can potentiate vitamin-D-induced coronary lesions.

ISSN:0731-5724    

DOI:10.1080/07315724.1990.10720365

出版商:Routledge    

年代:1990

数据来源: Taylor