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Biomedical subjects

J A Tur

Publications and source records attributed to J A Tur.

At least 19 recordsLinked to original sources
PubMed2006

Nutritional assessment of patients affected by porphyria variegata.

AIMS: To describe the nutritional status and dietary practices of patients affected by porphyria variegata, paying special attention to the consumption of nutrients that may help or hinder the condition, and to assess the compliance with prevalent nutritional recommendations. METHODS: Cross-sectional study. 24 individuals affected by porphyria variegata (16 females and 8 males; mean age 46.8 (SD 19.5) years) from the Balearic Islands (Spain) recruited through the Balearic Porphyria Association. Dietary questionnaires (7-day dietary record and a semi-quantitative food frequency questionnaire), socio-demographic, lifestyle and health status interviews and anthropometric measurements were carried out. RESULTS: According to current recommendations for the Spanish population and to specific recommendations for porphyria patients, the daily intake of saturated fat (13.2% of total energy), sugars (16.9% of total E), cholesterol (387 mg) and alcoholic beverages (1.1 servings per day) were too high whereas the consumption of total carbohydrates (43.5% of total E), vitamin E (69.5% of RDI), beta-carotene (63.1% of RDI) and vitamin D (42.4% of RDI) was lower than recommended. CONCLUSIONS: Dietary pattern observed among porphyria variegata patients was in line with current dietary trends in the Balearic Islands. Nutritional recommendations to these individuals for the management of porphyria are poorly met. It is necessary to translate these recommendations into food-based dietary guidelines based on prevailing dietary patterns.

Anthropometry↗
PubMed2006

Vitamin C supplementation influences the antioxidant response and nitric oxide handling of erythrocytes and lymphocytes to diving apnea.

OBJECTIVE: We have investigated the influence of vitamin C diet supplementation on the antioxidant response and nitrite levels in lymphocytes and erythrocytes during diving apnea. SUBJECTS: Seven male professional apnea divers participated in a double blind crossover study. Divers were randomly assigned to either vitamin C supplemented or placebo groups. The subjects did not take any other supplements than the ones provided for this study. INTERVENTION: One group was supplemented with vitamin C capsules (1 g per day) for 7 days while the other group took a placebo composed of lactose. The usual dietary habits of participants were assessed using a self-reported 7-days 24-h recall before the day of the study. Blood samples were taken under basal conditions, immediately after diving apnea for 4 h and after 1 h of recovery. RESULTS: Catalase activity increased in erythrocytes (23%) and superoxide dismutase increased in lymphocytes (35%) during the recovery only in the placebo group. Lymphocyte ascorbate levels increased in the supplemented group after diving (85%) and maintained high at recovery. Plasma nitrite levels increased about twofold in both groups during the recovery. Erythrocyte nitrite levels increased after diving (50%) and about twofold during the recovery in the supplemented group. Nitrite levels and iNOS levels in lymphocytes were higher in the placebo group than in the supplemented during the recovery. Erythrocyte carbonyl derivates were unchanged in all situations. CONCLUSIONS: Vitamin C supplementation influenced the antioxidant response and NO handling in erythrocytes and lymphocytes to the oxidative stress induced by hypoxia-reoxygenation.

Antioxidants↗
PubMed2005

Differential response of plasma and immune cell's vitamin E levels to physical activity and antioxidant vitamin supplementation.

OBJECTIVE: To assess the differential response of plasma, lymphocyte and neutrophil vitamin E levels to high-intensity physical activity and to vitamin C and E supplementation. SUBJECTS: In all, 14 male trained amateur runners (32-36 y old) were randomly divided in two groups (supplemented and placebo), and participated in a half marathon race. The subjects did not take any other supplements than the ones provided for this study. INTERVENTION: Vitamin C (152 mg/day) and E (50 mg/day) supplementation was administrated to athletes for a month, using a new almond-based isotonic and energetic beverage (supplemented group). The usual dietary habits of participants were assessed using a self-reported 7-day 24-h recall before the day of the study. To avoid the beverage influence, nonenriched vitamin C and E almond-based isotonic and energetic beverage was given to the placebo group. After 1 month, subjects participated in a half marathon race (21 km run). Vitamin E concentration was determined in plasma, neutrophils and lymphocytes before and immediately after the race, and 3 h after finishing the race. RESULTS: Daily energy intake and caloric profile of supplemented and placebo group were not different except for vitamin C and E supplementation. Vitamin supplementation and exercise had no effect on vitamins E levels in plasma. The exercise significantly (P<0.05) increased the lymphocyte vitamin E concentration both in the placebo (+119%) and supplemented groups (+128%), and neutrophil vitamin E content in the supplemented group (+88%). These levels remained significantly (P<0.05) high after the short recovery. After exercise, vitamin E levels in lymphocytes and neutrophils of supplemented subjects were practically twice the levels before exercise, whereas neutrophil vitamin E content of the placebo group was close to those in plasma. CONCLUSION: After endurance exercise, lymphocytes increased their vitamin E content in the supplemented and placebo subjects whereas this trend in neutrophils was just observed in the supplemented group. The determination of vitamin E content in lymphocytes and neutrophils after exercise is a useful tool to assess the functional status of vitamin E.

Adult↗
PubMed2005

Pre-exercise antioxidant enzyme activities determine the antioxidant enzyme erythrocyte response to exercise.

Free radical production increases during exercise and oxidative damage occurs in several tissues. We examined the effects of three different exercise tests on the pattern of change of erythrocyte enzyme antioxidant activities. The tests were a short maximal exercise test, a submaximal prolonged exercise test and a cycling stage during competition. The participants were amateur and professional cyclists with different training statuses and different basal erythrocyte antioxidant enzyme activities. The maximal test produced no changes in the erythrocyte antioxidant enzyme activities of amateur sportsmen. The submaximal test, performed at 80% of maximal oxygen uptake, decreased erythrocyte catalase (12%), glutathione peroxidase determined with H2O2 (14%) and glutathione reductase (16%); superoxide dismutase activity increased by about 25%. The cycling stage performed by professional cyclists increased erythrocyte catalase (29%) and glutathione reductase (10%) activities. The in vivo changes in glutathione reductase activity were confirmed by in vitro measurements: hydrogen peroxide decreased and the presence of catalase increased the activity of this enzyme. In conclusion, we suggest that the different erythrocyte antioxidant enzyme responses to diverse exercise tests can be explained by the effects of hydrogen peroxide and the superoxide anion on the antioxidant enzyme activities in erythrocytes.

Adult↗
PubMed2003

Olive oil and the Mediterranean diet: beyond the rhetoric.

OBJECTIVE: The purpose of this study was to analyze the association of food, nutrient and energy intakes with olive oil consumption in Spain. DESIGN: Cross-sectional study by face-to-face interview. SETTING: Population-based random sample derived from the Catalan Nutrition Survey. SUBJECTS: In total, 1600 individuals between 18 and 60 y of age. INTERVENTION: Two 24-h recalls were administered to measure food and nutrient intakes. Food consumption and nutrient intakes were analyzed comparing the highest and lowest quartiles of olive oil consumption. RESULTS: Those with the highest consumption of olive oil (greater than 13.5% of total calories, fourth quartile) consumed less cereal, baked goods, whole milk, sausages, candy, fruit juice and soft drinks, but more fish, eggs, vegetables and added fats, as compared to those with the lowest olive oil consumption (less than 6.8% of total calories, first quartile). The group with the greatest olive oil consumption also demonstrated high total fat intake, although saturated fats showed a lower percentage of total energy intake. Vitamin intake was more adequate in those with the highest consumption of olive oil. CONCLUSION: Olive oil is a key contributor to the healthy aspects attributed to the Mediterranean diet, and as such, nutritional objectives in Mediterranean countries should address reducing saturated fats, without modifying quantities of olive oil.

Adolescent↗
PubMed2002

Diet supplementation with vitamin E, vitamin C and beta-carotene cocktail enhances basal neutrophil antioxidant enzymes in athletes.

Exercise increases oxygen consumption and causes a disturbance of intracellular pro-oxidant-antioxidant homeostasis. Few data are available as to the cumulative effects of exercise on the antioxidant defenses of the neutrophil. We studied the effects of 90 days' supplementation with placebo or an antioxidant cocktail of vitamin E (500 mg/day) and beta-carotene (30 mg/day) and the last 15 days also with vitamin C (1 g/day) on sportsmen's basal neutrophil antioxidant defenses. We analyzed the activities of catalase, glutathione peroxidase, glutathione reductase and the activities and levels of superoxide dismutase, glutathione and glutathione disulfide in neutrophils purified from antecubital vein blood of sportsmen before and after diet supplementation. Plasma vitamin E, beta-carotene and vitamin C concentrations in the antioxidant-supplemented group were approximately 1.6, 10, and 1.2 times higher respectively than those of the placebo group. The antioxidant-supplemented group presented a significantly higher glutathione versus glutathione disulfide ratio in neutrophils (about 20%) than the placebo one. Antioxidant supplementation enhances the antioxidant enzyme activity of superoxide dismutase and catalase in neutrophils.

Adult↗
PubMed2001

Vitamins in Spanish food patterns: the eVe Study.

OBJECTIVE: To describe vitamin intakes in Spanish food patterns, identify groups at risk for inadequacy and determine conditioning factors that may influence this situation. DESIGN: Pooled-analysis of eight cross-sectional regional nutrition surveys. SUBJECTS: Ten thousand two hundred and eight free-living subjects (4728 men, 5480 women) aged 25-60 years. Respondents of population nutritional surveys carried out in eight Spanish regions (Alicante, Andalucia, Balearic Islands, Canary Islands, Catalunya, Galicia, Madrid and Basque Country) from 1990 to 1998. The samples were pooled together and weighted to build a national random sample. METHODS: Dietary assessment by means of repeated 24-hour recall using photograph models to estimate portion size. Adjusted data for intra-individual variation were used to estimate the prevalence of inadequate intake. A Diet Quality Score (DQS) was computed considering the risk for inadequate intake for folate, vitamin C, vitamin A and vitamin E. DQS scores vary between 0 (good) and 4 (very poor). Influence of lifestyle (smoking, alcohol consumption and physical activity) was considered as well. RESULTS: Inadequate intakes (<2/3 Recommended Dietary Intake) were estimated in more than 10% of the sample for riboflavin (in men), folate (in women), vitamin C, vitamin A, vitamin D and vitamin E. More than 35% of the sample had diets classified as poor quality or very poor quality. Factors identified to have an influence on a poor-quality diet were old age, low education level and low socio-economical level. A sedentary lifestyle, smoking, usual consumption of alcohol and being overweight were conditioning factors for a poor-quality diet as well. CONCLUSION: Results from The eVe Study suggest that a high proportion of the Spanish population has inadequate intakes for at least one nutrient and nearly 50% should adjust their usual food pattern towards a more nutrient-dense, healthier diet.

Adult↗
PubMed1998

Effect of atrial natriuretic peptide on alpha-methyl-D-glucoside intestinal active uptake in rats.

In vivo, atrial natriuretic peptide (ANP) inhibits water and sodium absorption by the intestine. In addition, ANP inhibits glucose (re)absorption at the level of both the intestine and kidney. ANP also decreases sodium absorption in the rat small intestine in vitro, but only if glucose is present on the luminal side of the tissue. These findings suggest that ANP inhibits the sodium-glucose cotransporter (SGLT) of enterocytes. In the present study the inhibitory effect of 1 microM ANP on SGLT1 in rat small intestine and colon was tested. For this purpose, the apparent kinetic constants of SGLT1 were determined using radioactive alpha-methyl-D-glucoside (alpha-MG), a non-metabolizable glucose analogue that selectively serves the luminal Na+-dependent intestinal uptake, but not the serosal-facilitated diffusion sugar carrier. In both tissues, incubation with ANP increased Km without modifying the Vmax. In addition, Vmax in the small intestine was found to be higher than in the colon. The evidence presented here suggests that ANP, through its second messenger, may be a competitive inhibitor of SGLT1. Since SGLT1 is also expressed in the brush-border membrane of the renal proximal tubule, we suggest that this peptide might regulate the hydro-saline balance at intestinal and proximal tubular nephron levels.

Animals↗
PubMed1996

Kinetic constants of alpha-methyl-D-glucoside transport in the chick small intestine during perinatal development.

The kinetic parameters of alpha-methyl-D-glucoside (alpha Glc1Me) have been determined in the small intestine in order to establish developmental and regional changes in the apical transport in embryos and newly hatched chicks. Results show that the apparent Michaelis constant (Km) values did not change during the period studied in each region of the small intestine. However, the ileum showed a smaller Km than that of the duodenum and jejunum, indicating an increase of the affinity of the carrier in the distal portion of the intestine and a significant contribution of the ileum to overall sugar absorption in the perinatal period. There were important changes in the diffusional component and in the mediated transport system capacity during this period, as well as in the different regions of the intestine. Significant increases in the maximal rate of transport (Vmax) were observed in all regions during the embryonic period until the second day after hatching, followed by a decline during the first week. During all the period studied, Vmax values from the jejunum were significantly greater than those from both the duodenum and the ileum at every age studied showing that the jejunum is the segment that is best suited for Na(+)-mediated uptake. Such changes which occur when the need for nutrients for rapid development are at their highest are not solely a result of diet composition, but rather in accordance with a genetic programme.

Animals↗
PubMed1996

Effect of dietary fatty acids on jejunal and ileal oleic acid uptake by rat brush border membrane vesicles.

To test the effect of dietary fatty acids on fatty acid uptake, the influx kinetics of a representative long-chain fatty acid, 3H-oleic acid, in both the jejunum and ileum of rats has been studied using brush border membrane vesicles (BBMV). Animals were fed with semipurified diets containing 5 g fat/100 g diet, as corn oil (control group), safflower oil (unsaturated group) and coconut oil hydrogenated (saturated group). With increasing unbound oleate concentration in the medium, the three dietary groups showed saturable kinetics in both jejunal and ileal BBMV (controls: Vmax = 0.15 +/- 0.01 nmol x mg protein-1 x 5 min-1 and Km = 136 +/- 29.1 nmol for jejunum, and Vmax = 0.23 +/- 0.03 nmol x mg protein-1 x 5 min-1 and Km = 196 +/- 50.3 nmol for ileum; unsaturated: Vmax = 0.28 +/- 0.05 nmol x mg protein-1 x 5 min-1 and Km = 242.7 +/- 91.8 nmol for jejunum, and Vmax = 1.29 +/- 0.06 nmol x mg protein-1 x 5 min-1 and Km = 509.8 +/- 97.5 nmol for ileum; saturated: Vmax = 0.03 +/- 0.01 nmol x mg protein-1 x 5 min-1 and Km = 124.5 +/- 72.6 nmol for jejunum, and Vmax = 0.04 +/- 0.01 nmol x mg protein -1.5 min-1 and Km = 205.6 +/- 85.3 nmol for ileum). These results support the theory that feeding an isocaloric diet containing only unsaturated fatty acids enhanced oleic acid uptake, and feeding an isocaloric diet containing only saturated fatty acids decreased oleic acid uptake. The results obtained in the present work also show the adaptative ability of jejunum and ileum to the type of dietary fat.

Animals↗
PubMed1996

Oleic acid uptake by jejunal and ileal rat brush border membrane vesicles.

In previous works, a membrane fatty acid transport system has been identified in brush border membrane vesicles, but no different intestinal regions were considered in these studies. To test the existence of a proximal-to-distal gradient of fat absorption along the small intestine, transmembrane influx kinetics of a representative long-chain fatty acid, 3H-oleic acid, in both jejunum and ileum of rat has been studied using brush border membrane vesicles (BBMV). With increasing concentration of unbound oleate in the medium, both jejunal and ileal BBMV showed saturable uptake kinetics (Vmax = 0.15 +/- 0.01 nmol.mg protein-1 x 5 min-1 and Km = 136 +/- 29.1 nmol for jejunum, and Vmax = 0.23 +/- 0.03 nmol.mg protein-1 x 5 min1 and Km = 196 +/- 50.3 nmol for ileum). These results support the hypothesis that oleic acid uptake occurs via a carrier-mediated transport mechanism in both jejunum and ileum. Furthermore, the existence of a proximal-to-distal gradient for fat absorption was apparent with a higher density of transport units (Vmax) in ileum compared to jejunum.

Animals↗
PubMed1996

Changes in intestinal alpha-methyl-D-glucoside uptake due to pregnancy and lactation in rats.

Uptake of alpha-methyl-D-glucoside, a nonmetabolizable glucose analogue, by everted intestinal sleeves was studied in virgin, pregnant and lactating rats. The animals showed an increase in jejunal and ileal tissue mass, mucosal mass, nominal surface area, and enzymatic activities. No changes were observed in the carrier affinity throughout the breeding stages. Nevertheless there was a significant increase in glucose carrier density (Vmax) per unit of length of jejunum and ileum in pregnant and lactating animals. Integrating the results obtained, and increased overall ability to transport hexoses by nonspecific adaptation can be observed in breeding stages.

Animals↗
PubMed1994

Disaccharidase activities in pregnant and lactating rats.

The changes in intestinal disaccharidase activities in pregnancy and lactation could be explained as a result of an adaptation to the energy demands of each reproductive stage. To examine these changes, disaccharidase activities (lactase, sucrase, maltase, and trehalase) were measured in the jejunum and ileum of virgin, pregnant and lactating Wistar rats. Minor changes in disaccharidase activities were observed in pregnancy, whereas an increase of disaccharidase activities per small intestine length normalized to body mass was observed in lactation.

Animals↗
PubMed1994

Morphological adaptive changes of small intestinal tract regions due to pregnancy and lactation in rats.

In order to know the adaptive changes of small intestine regions (duodenum, and proximal, medial and distal jejunum-ileum) due to the reproductive stage (virgin, pregnancy and lactation), the weight, mucosal proportion, mucosal DNA and protein contents and protein/DNA ratio in female Wistar rats were measured. Pregnancy induces hypertrophy of the proximal half of the small intestine (duodenum and proximal jejunum-ileum), whereas lactation induces hyperplasia in all small intestinal regions and also hypertrophy but only in the duodenum.

Animals↗
PubMed1992

Dietary effects upon calcium oxalate urolithiasis risk.

An animal model involving rats fed with different diets (high protein, high carbohydrate, high lipid, high fiber and control balanced diet) was used to evaluate the dietary effects on the main oxalocalcic urolithogenic parameters. It was found that the inhibitory factors that prevent calcium oxalate stone formation (citrate and magnesium) were clearly more favorable in the group of rats fed with a balanced diet. However, factors favouring the heterogeneous calcium phosphate nucleation were also found in the balanced diet. On the other hand, factors facilitating the heterogeneous uric acid nucleation were found in rats treated with high protein, high lipid, high carbohydrate and high fiber diets. In conclusion it seems that the balanced diet appears to be the less lithogenic one.

Animals↗
PubMed1992

Effect of "Rosa Canina" infusion and magnesium on the urinary risk factors of calcium oxalate urolithiasis.

The effects on the calcium oxalate urolithiasis urinary risk factors of "Rosa Canina", in herb infusion form, and magnesium chloride have been studied using female Wistar rats under balanced dietary conditions. No significant effects on the volume of liquids drunk or on creatinine, phosphate, and oxalate urinary concentrations and excretions were observed. The herb infusion did not cause any diuretic effect. Calciuria decreased and citraturia increased when taking the herb infusion, and vice versa when taking magnesium chloride. Magnesium chloride decreased the urinary pH value, but this effect was not observed when magnesium chloride was administered with herb infusion. In conclusion, the same beneficial effects of the studied infusion herb on calcium oxalate urolithiasis urinary risk factors can be clearly detected. An interesting fact is that it seems that some possible effects depend on dietary components, thus, i.e., an increase in the urinary pH was only detected when the intake of the herb infusion was studied in a magnesium chloride-supplemented diet.

Animals↗
PubMed1991

Effect of cafeteria diet on the gastrointestinal transit and emptying in the rat.

1. When gastrointestinal transit and emptying of intraluminal contents were studied using a radioactive tracer marker [( 14C]PEG-4000), the fastest gastric transit and the slowest overall transit time were observed in female Wistar rats (1-3 months old) after they were fed a cafeteria diet (a hypercaloric diet). 2. The small intestine length of cafeteria fed rats was higher than lean rats, whereas the stomach and large bowel length showed no difference between cafeteria and lean rats. 3. A state of mild obesity was obtained after rats were fed a cafeteria diet. This obesity was demonstrated by the highest body weight and the highest gain of white adipose tissue in rats fed a cafeteria diet.

Animals↗