Characterization of digital dispersive spectrometers by low coherence interferometry

We propose a procedure to determine the spectral response of digital dispersive spectrometers without previous knowledge of any parameter of the system. The method consists of applying the Fourier transform spectroscopy technique to each pixel of the detection plane, a CCD camera, to obtain its individual spectral response. From this simple procedure, the system-point spread function and the effect of the finite pixel width are taken into account giving rise to a response matrix that fully characterizes the spectrometer. Using the response matrix information we find the resolving power of a given spectrometer, predict in advance its response to any virtual input spectrum and improve numerically the spectrometer's resolution. We consider that the presented approach could be useful in most spectroscopic branches such as in computational spectroscopy, optical coherence tomography, hyperspectral imaging, spectral interferometry and analytical chemistry, among others.

Molecular mechanisms by which white tea prevents oxidative stress

The flavonoid content of tea (Camellia sinensis) has beneficial properties in the prevention of diseases. However, the mechanisms by which white tea can protect against oxidative stress remain unclear. To shed light on this issue, rats were given distilled water (controls), 0.15 mg/day (dose 1) or 0.45 mg/day (dose 2) of solid tea extract/kg body weight for 12 months. All the animals received an injection of adriamycin (ADR; 10 mg/kg body weight), except half of the control group, which were given an injection of saline solution. The expression of the nuclear factor, E2-related factor 2 (Nrf2), NAD(P)H:quinone oxidoreductase 1 (Nqo1), glutathione S-transferase (Gst), haem oxygenase-1 (Ho1), catalase (Cat), superoxide dismutase (Sod) and glutathione reductase (Gr) in liver was analysed by real-time PCR, and the activity of catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR) was measured spectrophotometrically. ADR significantly increased the expression of Nrf2, Gst, Nqo1, Ho1, Cat, Sod and Gr with respect to the control levels and also increased the activity of CAT, SOD and GR. The intake of white tea increased in a higher degree the expression of Nrf2, Gst, Nqo1 and Ho1 in the tea + ADR group compared with the control group and C + ADR group. In addition, tea + ADR groups decreased the expression and activity of CAT, SOD and GR in a dose-dependent manner.

[Development of a current version of a software application for research and practice in human nutrition (GRUNUMUR 2.0)]

The aim of this paper is the description of a new version of the software application GRUNUMUR, a useful tool for human nutrition studies designed by the Nutrition Research Group from the Murcia University. Similar to the first, this second version offers the possibility to address different types of study: dietary habits (24 h recall, 7-days dietary record and Food Frequency Questionnaire), epidemiological, anthropometrical and clinical studies. The new version, called GRUNUMUR 2.0, compatible with the first one, has an online help system for all functions of the application, providing the user tasks, allows safe storage of a virtually unlimited number of results, in an orderly and organized way, you can retrieve it when required, through a system of backups and scheduled maintenance and unattended (tasks performed by a server), another advantage is its total accessibility, both from the university intranet (www.um.es) and from the internet, it works via Web Browser (http://senver.inf.um.es/esen), and finally, allows data to be exported to Excel for further processing with other applications as well as publishing reports in PDF, to deliver study participants if necessary. The new version has been validated by comparing the extracted results with those obtained from the other software with no significant differences for any of the variables analyzed. The application GRUNUMUR 2.0 is a tool improved, useful and reliable for addressing human nutrition studies.

Genetic testing of sperm donors for cystic fibrosis and spinal muscular atrophy: evaluation of clinical utility

OBJECTIVE

To evaluate the clinical utility of genetic testing for cystic fibrosis (CF) and spinal muscular atrophy (SMA) in sperm donors.

STUDY DESIGN

We studied the results of the genetic tests for CF and SMA applied to 372 sperm donor candidates. The CF carrier screening test analysed 32 mutations on the CFTR gene. Regarding SMA, the carrier test studied possible deletions of SMN1/2 by Multiplex Ligation-dependent Probe Amplification (MLPA) methodology.

RESULTS

The carrier frequency obtained was greater for SMA than for CF. After adjusting the results obtained for the sensitivity of the tests, and taking into account the prevalence of female carriers in our population, the probability of transmission of the disease to the child from a donor with a negative genetic test was about five times lower in the case of SMA than in CF, although this difference was not statistically significant. The number of donors needed to screen (NNS) to avoid the occurrence of a child being affected by CF and SMA in our population was similar in both cases (1591 vs. 1536).

CONCLUSIONS

This study demonstrates the need to include SMA among the diseases for which genetic screening is performed in the process of sperm donor selection. We believe that testing donors for SMA is as important and as useful as doing so for CF.

Nutrition and prevalence of undernutrition assessed by different diagnostic criteria in nursing homes for elderly people

BACKGROUND

Undernutrition is the state produced by the intake of insufficient energy, macronutrients or micronutrients. The present study aimed to assess the prevalence of undernutrition using 10 different diagnostic criteria described in the literature and to assess its association with energy intake in an institutionalised elderly population.

METHODS

The cross-sectional study included 213 subjects, aged 65-96 years (135 women and 78 men), who lived in seven nursing homes in the province of Murcia, on the Mediterranean coast of Spain. Dietary intake and anthropometric and biochemical parameters were assessed, and 10 different diagnostic criteria, taken from studies of elderly subjects similar to our population, were applied.

RESULTS

The mean dietary intakes appeared to cover the recommended dietary intake for a Spanish elderly population. However, only 58.2% of the studied subjects consumed 100% of the recommended dietary intake and 15.5% of the subjects had an energy intake below 80% of the recommended dietary intake. Depending on the criteria used for the diagnosis, the proportion of patients with undernutrition varied between 2% and 57%. When the relationship between undernourishment, as defined by the different methods and intake deficiency, was assessed, a statistically significant relationship was only found for five of the 10 diagnostic criteria assessed.

CONCLUSIONS

  Research needs to focus on the development and evaluation of specific nutritional assessment tools for application to older people aiming to improve the detection of those suffering (or who are at risk of suffering) undernutrition.

[Prevalence of malnutrition and influence of oral nutritional supplementation on nutritional status in institutionalized elderly]

BACKGROUND

Nutritional supplementation might be an effective strategy for improving the nutritional status and the quality of life of institutionalized fragile elderly.

OBJECTIVES

The prevalence of malnutrition and its relation with disease, and the influence of dietary supplementation by means of oral formulas on the nutritional status of elderly nursing home residents were assessed.

METHODS

Two studies were carried out, one a cross-sectional survey in 31 subjects and the other a longitudinal-sectional survey in 19 subjects, both groups living in a public nursing home in the city of Murcia (SE Spain). Body mass index (BMI), serum albumin concentration (ALB) and geriatric nutritional risk index (GNRI) were assessed as markers of potential malnutrition. Illnesses were ascertained from medical records.

RESULTS AND DISCUSSION

The prevalence of malnutrition of the total collective was high (39%), and especially in the fragile subjects (50%). The administration of oral nutritional supplements in the usual diet for 12 months significantly increased ALB and GNRI, and had no effect on body weigh and BMI. Jointly, these effects decreased the in the number of subjects at high nutritional risk and increased the number of subjects with a low or zero risk of malnutrition.

CONCLUSION

The administration of oral nutritional supplements in the usual diet of this elderly collective is an effective clinical strategy in nutritional therapy.

Dietary self-selection of protein-unbalanced diets supplemented with three essential amino acids in Nile tilapia

Animals do not eat whatever food item they encounter, but choose different foods that best match their requirements. Fish exhibit such "nutritional wisdom" and adapt their feeding behaviour and food intake according to their needs and the nutritional properties of diets. In this paper, we tested the ability of Nile tilapia to select between diets with a balanced or unbalanced composition of essential amino acids. To this end, three different diets were prepared: a gelatine based diet (D(1)), a gelatine diet supplemented with three essential amino acids (EAA, l-tryptophane, l-methionine, l-threonine) (D(2)), and a diet containing only cellulose and the three crystalline EAA (D(3)). In addition, the putative role of both orosensorial factors (using pellets vs capsules) and social interactions (single vs groups of ten fish) was investigated. To this end, a total of 68 male tilapia of about 141±48 g (mean±S.D.) were challenged, individually or in groups, to select between D(1)vs D(2) using pellets dispensed by self-feeders (exp. 1). In another experiment (exp. 2), 11 individual fish were challenged to select encapsulated diets with non flavour or smell proprieties (D(1)vs D(2)), and in exp. 3 fish were challenged to self-supplementation in EAA (D(1)vs D(3)). The results showed the ability of tilapia to avoid the EAA-deficient diet, choosing 82.2% D(2) in the case of individual fish, and 80.8% D(2) in the case of fish groups. Dietary selection was not directly driven by the orosensorial characteristics of food, since tilapia sustained a higher preference for D(2) when fed with encapsulated diets. Finally, in exp. 3 tilapia self-supplemented the EAA deficiency by selecting a synchronised combination of D(1) and D(3) that matched their nutritional requirements. These findings highlighted the capacity of fish to make dietary selection based on the EAA content, which should be considered when discussing food intake regulation mechanisms, and diet formulation and supplementation with EAA.

Cambrian stalked echinoderms show unexpected plasticity of arm construction

Feeding arms carrying coelomic extensions of the theca are thought to be unique to crinoids among stemmed echinoderms. However, a new two-armed echinoderm from the earliest Middle Cambrian of Spain displays a highly unexpected morphology. X-ray microtomographic analysis of its arms shows they are polyplated in their proximal part with a dorsal series of uniserial elements enclosing a large coelomic lumen. Distally, the arm transforms into the more standard biserial structure of a blastozoan brachiole. Phylogenetic analysis demonstrates that this taxon lies basal to rhombiferans as sister-group to pleurocystitid and glyptocystitid blastozoans, drawing those clades deep into the Cambrian. We demonstrate that Cambrian echinoderms show surprising variability in the way their appendages are constructed, and that the appendages of at least some blastozoans arose as direct outgrowths of the body in much the same way as the arms of crinoids.

Dietary intake and iron status of institutionalized elderly people: relationship with different factors

OBJECTIVES

Aims of the study were to investigate iron status in institutionalized elderly subjects and to determine its association with different factors including: age, gender, body mass index, dietary intake, consumption of iron supplements, functional status and disease.

DESIGN

A cross-sectional study.

SETTING

Seven public nursing homes.

PARTICIPANTS

252 subjects, aged 65-96 years.

MEASUREMENTS

Food intake was assessed by a 4-day weighed-food record. Iron status indices were measured. Barthel' s Index was used to evaluate functional status. Illnesses were ascertained from medical records.

RESULTS

Anemia was found in 25.4% of subjects studied. Average dietary intakes fulfilled the amounts of Recommended Dietary Intake for Spanish elderly population, except for folate. A substantial percentage of subjects exhibited folate dietary deficit (89.2%). Mean (SD) BMI was 27.8 (6.4) kg/m2, and functional status 78.1 (26.5). Taking into account hematocrit, red blood cell count and serum iron concentration values, poor iron status was significantly more common in men (59.4, 61.4 and 16.8%, respectively) than in women (36.4, 36.4 and 6.0%, respectively). Hemoglobin concentration was positively associated with the energy and nutrient dietary intake, and negatively with age, BMI and functional status.

CONCLUSIONS

Based on World Health Organization criteria, anemia was found in 25.4% of elderly subjects studied. Iron deficiency seems to be the main cause of anemia, and chronic disease the second cause of anemia. Dietary intake is not one of the principal causes of anemia in the study population, except for folate intake.

[Strategies for improving nutritional value of the meals offered by public nursing homes for the elderly]

BACKGROUND

In developed countries, elderly people are considered a group of high risk for possible nutritional imbalances, particularly if they are institutionalized.

OBJECTIVES

In the present study, the nutritional value of the meals offered by public nursing homes for the elderly in province of Murcia (Spain) was assessed, to compare the results with Spanish recommendations and to propose possible strategies for improving the nutritional status of the residents.

METHODS

We studied 252 meals offered by six nursing homes, evaluating the energy and macronutrient contents, caloric profile, fat quality and cholesterol and fiber contents. The results were compared with Spanish recommendations for elderly people, and recommendations for a balanced and Mediterranean diet.

RESULTS AND DISCUSSION

The average energy content of the meals widely fulfilled the amounts of Recommended Dietary Intake for the elderly population. The caloric profile was adequate as regards proteins, low in carbohydrates and high in lipids. The fat quality was adequate, the cholesterol content was higher and the fiber content lower that the recommended amounts.

CONCLUSIONS

Among possible strategies to improve the nutritional value of the meals, could be a reduction in the fat and cholesterol contents and an increase in carbohydrate and fiber contents, by replacing some red meat dishes by legumes, bread and refined cereals by wholemeal foods, and fat full dairy products by low fat equivalents.

Dietary fructooligosaccharides and potential benefits on health

Fructooligosaccharides (FOS) are oligosaccharides that occur naturally in plants such as onion, chicory, garlic, asparagus, banana, artichoke, among many others. They are composed of linear chains of fructose units, linked by beta (2-1) bonds. The number of fructose units ranges from 2 to 60 and often terminate in a glucose unit. Dietary FOS are not hydrolyzed by small intestinal glycosidases and reach the cecum structurally unchanged. There, they are metabolized by the intestinal microflora to form short-chain carboxylic acids, L -lactate, CO(2), hydrogen and other metabolites. FOS have a number of interesting properties, including a low sweetness intensity; they are also calorie free, non-cariogenic and are considered as soluble dietary fibre. Furthermore, FOS have important beneficial physiological effects such as low carcinogenicity, a prebiotic effect, improved mineral absorption and decreased levels of serum cholesterol, triacylglycerols and phospholipids. Currently FOS are increasingly included in food products and infant formulas due to their prebiotic effect stimulate the growth of nonpathogenic intestinal microflora. Their consumption increases fecal bolus and the frequency of depositions, while a dose of 4-15 g/day given to healthy subjects will reduce constipation, considered one of the growing problems of modern society, and newborns during the first months of life.

Adiponectin is associated with serum and adipose tissue fatty acid composition in rats

The objective of the present work is to analyse the relationships between changes in adiponectin and fatty acid composition in serum and adipose tissue in rats. Samples from serum and different adipose depots (periovarian, mesenteric and subcutaneous) were obtained from ageing rats (14- and 20-month-old) to determine fatty acid composition (gasliquid chromatography). In serum, insulin (radioimmunoassay) and adiponectin levels (enzyme-linked immunosorbent assay) were also measured, while adiponectin gene expression was analysed (real time-qPCR) in all fat depots. There were significant age-related reductions in adipose tissue saturated (SFA) and trans fatty acids and increases in monounsaturated fatty acids in parallel with diminished adiponectin expression in periovarian and mesenteric adipose tissue (p<0.05). Age-independent negative correlations were found between adiponectin gene expression in mesenteric adipose tissue and C12:0, C14:0 and C18:2 trans fatty acids (p<0.05). There was a positive association between serum adiponectin and adipose tissue oleic acid, while palmitoleic acid was negatively associated with adiponectin expression and positively correlated with insulin concentration. For the first time, positive relationships are reported between the proportion of n-6 polyunsaturated fatty acids (PUFA) in adipose tissue and adiponectin concentration and expression. In summary, adiponectin expression and serum levels are associated with fatty acid composition, with SFA, trans and palmitoleic fatty acids appearing as negative markers for adiponectin, and oleic acid and n-6 PUFA as positive ones. In addition, most associations were found in the visceral depots, highlighting the importance of visceral fat in the metabolic status.

Is soft drink consumption associated with body composition? A cross-sectional study in Spanish adolescents

OBJECTIVES

Published data about the association between the consumption of sweetened soft-drinks (SSD) and obesity in childhood are controversial and still inconsistent. In addition, data are lacking in the Spanish population. The purpose of this study was therefore, to explore the cross-sectional association between body composition-related parameters and SSD consumption in Spanish adolescents.

SUBJECTS AND METHODS

A representative sample of 1,523 adolescents (768 boys and 755 girls), with complete dietary data as well as anthropometric measurements, were included in this study. Weight, height, waist circumferences, and 6 skinfolds were measured, and BMI and percentage body fat were calculated. From a 24h dietary recall the subjects were grouped in 3 groups according to their SSD consumption: 1) Non-consumers (0 g of SSD consumption); 2) Moderate consumption (< 336 g/day of SSD, equivalent to the average SSD portion size); and 3) High consumption (> 336 g/day of SSD).

RESULTS

67% males and 75% females did not consume any SSD the day before the dietary recall interview. Males consumed more SSD than females. Regarding the association between SSD consumption and measures of obesity, no difference was observed between the three groups of SSD consumption in any of the anthropometric measurement, BMI or body fat.

CONCLUSION

As no association was present between SSD consumption and obesity in our cross-sectional study we suggest that dietary patterns and habits as well as lifestyle factors such as physical activity should be present when examining cross-sectional or longitudinal relationships with obesity. Multidisciplinary intervention studies are crucial when trying to develop solutions against the increasing obesity epidemic.

Insulin effect on adipose tissue (AT) adiponectin expression is regulated by the insulin resistance status of the patients

OBJECTIVE

The objective of the present study was to determine a possible depot-specific effect of insulin-stimulation on adiponectin gene expression in adipose tissue (AT) explants from subcutaneous and visceral AT. A secondary aim was to analyse the associations of adiponectin plasma levels, as well as control and insulin-stimulated gene expression levels with different features of the metabolic syndrome.

DESIGN

Visceral and subcutaneous AT biopsies were obtained from 20 subjects (10 men and 10 women) with morbid obesity. Metabolic syndrome and other clinical features were studied. Adiponectin expression from isolated adipocytes was measured both in control and after insulin-stimulation conditions by quantitative PCR.

RESULTS

Subcutaneous adipocytes expressed significantly higher amounts of adiponectin mRNA than visceral tissue (P = 0.027). Insulin increased adiponectin expression specifically in the omental tissue (P = 0.011). In these patients, waist : hip ratio was directly correlated with adiponectin expression in the visceral depot (r = 0.660; P = 0.014), while fasting glucose levels were inversely associated with adiponectin mRNA in the subcutaneous tissue (r =-0.604; P = 0.022). Adiponectin expression after addition of insulin was positively correlated with some metabolic risk factors (cholesterol, LDL-cholesterol, insulin, C-peptide). Interestingly, local insulin induced an up-regulation of adiponectin expression in the AT of those patients with higher metabolic syndrome disturbances.

CONCLUSIONS

Our results clearly demonstrate that insulin exerts a stimulating effect on adiponectin gene expression in a depot-specific manner. The AT response to insulin stimulus depends on the physiopathological situation, being higher in those individuals with impaired insulin-sensitivity and lipid metabolism.

Anthropometric indexes for visceral fat estimation in overweight/obese women attending to age and menopausal status

The objective of the present study was to assess the usefulness and accuracy of different anthropometric measurements in the diagnosis of abdominal visceral obesity in overweight/obese women attending to age and menopausal status. The secondary objective was to evaluate the usefulness of waist circumference (WC) in two different sites. Different anthropometric indicators were assessed in 55 overweight/obese women (n=22 premenopausal, n=33 postmenopausal; BMI > 25 kg/m(2)) and compared with computed tomography measurements of abdominal visceral adipose tissue (VA) performed as a single scan at L4-L5. Our results show that VA significantly differs between both groups of women. Waist2-hip ratio (W2HR) was significantly correlated to VA in both groups of women. After multiple regression analysis, sagittal diameter was an independent parameter to predict VA. However, no significant differences were obtained in this diameter between both groups. None of the waist circumferences were significantly associated to VA. Moreover, the two sites of WC were statistically different. In conclusion, waist-to-hip ratio, measured immediately above the iliac crest (W2HR) seems to be the more appropriated anthropometric index for the estimation of visceral fat in women, independently of age. Although sagittal diameter is a fine parameter to predict visceral fat area, it is not adequate to discriminate between women of different age or menopausal status. In contrast with previous findings, waist circumferences do not seem to be useful for predicting VA.

Cortisol secretary pattern and glucocorticoid feedback sensitivity in women from a Mediterranean area: relationship with anthropometric characteristics, dietary intake and plasma fatty acid profile

BACKGROUND

Chronic stress is associated with a dysfunctional hypothalamic-pituitary-adrenal (HPA) axis consisting on disturbances on the cortisol response and lipid metabolism.

OBJECTIVE

To evaluate the HPA axis activity in women from a Mediterranean area, comparing three different measurements: daily cortisol secretory variability, postprandial cortisol secretion and glucocorticoid feedback sensitivity. In addition, HPA axis disturbance is correlated with dietary habits and plasma fatty acid profiles.

DESIGN

The participants were 41 women born during the first 6 months of 1960 and living in a Mediterranean area (Murcia, Spain). They were of normal weight, with a waist circumference of 80.5 +/- 9.3 cm. Their salivary cortisol levels, 7-day dietary record and plasma fatty acid profile were evaluated. Daily cortisol variability and postlunch cortisol secretion were recorded and a dexamethasone suppression test is performed in order to detect possible HPA disturbance.

RESULTS

Both the methods used for HPA axis evaluation were positively correlated (r = 0.448, P = 0.004). Subjects with normal diurnal curves (high cortisol variability) showed significantly higher cortisol values in the morning and postprandial cortisol secretion than women with pathological curves (medium and low variability). Cortisol variability was inversely correlated with waist circumference (r = -0.312, P = 0.047), suggesting that a disturbed HPA axis response may lead to an android pattern of body fat distribution. Dietary fat and saturated fatty acid intake were lower in the high cortisol variability group, while monounsaturated fatty acid intake was higher (P < 0.05). No major differences were reported in plasma fatty acid profile.

CONCLUSIONS

A disturbed HPA axis is associated with abdominal fat distribution and a higher content of fat and saturated fatty acids in the diet. Women who chose a dietary pattern closer to the Mediterranean diet, with high monounsaturated fatty acid intake, showed lower levels on HPA axis disturbance.

Relationship between fat cell size and number and fatty acid composition in adipose tissue from different fat depots in overweight/obese humans

OBJECTIVE

To evaluate the body fat distribution and fat cell size and number in an overweight/obese population from both genders, and to determine the possible relationship between fat cell data from three different adipose tissue localizations (subcutaneous (SA), perivisceral and omental) and adipose tissue composition and dietary fatty acid.

DESIGN

The sample consisted of 84 overweight/obese patients (29 men and 55 women) who have undergone abdominal surgery. The adipocyte size and total fat cell number was studied. Fat cell data were related with anthropometric, adipose tissue and subject's habitual diet fatty acid composition.

MEASUREMENTS

Fat cell size was measured according to a Sjöström method from the three adipose depots. Total fat cell number was also calculated. The fatty acid composition of adipose tissue was examined by gas chromatography. The subjects diet was studied by a 7 days dietary record.

RESULTS

Our data showed a negative relationship between the adipocyte size and the n-6 and n-3 fatty acids content of the SA adipose tissue (r=-0.286, P=0,040; r=-0.300, P=0.030) respectively, and the n-6 in the omental depots (r=-0.407, P=0.049) in the total population. Positive associations with the total of saturated (r=0.357, P=0.045) and negative (r=-0.544, P=0.001) with the n-9 fatty acids were observed when the relationship between the adipocyte number and the fatty acid composition of the different anatomical fat regions was studied. Dietary fatty acids composition positively correlated with fat cell size for the myristic acid (14:0) in men in the visceral depot (r=0.822, P=0.023), and for the saturated fatty acids (SFAs) in women in the omental depot (r=0.486, P=0.035).

CONCLUSION

In the present study, for the first time in humans we found that n-3 and n-6 fatty acids are related to a reduced adipocyte size according to the depot localization. In contrast, adipose tissue and dietary SFAs significantly correlated with an increase in fat cell size and number. No significant associations were found between n-9 acids content and adipocyte size. However, n-9 adipose tissue fatty acids content was inversely associated with fat cell number showing that this type of fatty acid could limit hyperplasia in obese populations. The differences observed in the three different regions, perivisceral, omental and SA fat, indicate that this population adipose tissue have depot-specific differences.

[Multivalent informatics application for studies of the nutritional status of the population. Assessment of food intake]

The aim of the study is the presentation and validation of a computer program, GRUNUMUR, designed for nutritional evaluation studies in great population groups, and to describe some of the results obtained after the application of this working tool. This program includes he following types of studies: a) dietary study; b) food habits study; c) anthropometric study and d) clinical study. The main advantage of GRUNUMUR is the possibility of being periodically actualized without any important software knowledge, and to be opened to the introduction of new data bases. The software program GRUNUMUR Is one more of the multiple programs described in the literature. However, once validated, this tool has the particularity of being developed after an important experience in the nutritional field and only with a scientific purpose. The result is a reliable tool, which facilitates nutrition research.

Adiposity and dietary intake in cardiovascular risk in an obese population from a Mediterranean area

The aim of the study was to determine the particular relevance of android fat distribution and dietary intake in cardiovascular risk in an obese Mediterranean population with high intake of monounsaturated fatty acids (MUFA) and to compare the findings with those from normal-weight subjects. For the study, 193 subjects aged 25-60 were selected: 118 obese (BMI > or = 27 kg/m2), and 75 normal-weight (BMI < 25 kg/m2). Cardiovascular risk factors including hypertension, dyslipidaemia, glucose intolerance and insulin resistance were assessed. Nutrient intake and body fat distribution were determined. Results show that MUFA were highly consumed in the total population (21% of total energy). The obese population was normolipidemic and normoinsulinemic. However, cardiovascular risk factors (CVRF) were significantly higher than in normal-weight (P < 0.05). Obese subjects derived a greater percentage of their energy intake from total fat and lower from carbohydrates and saturated fats (P < 0.05). BMI and waist-hip ratio positively correlated with fat percentage of total energy intake and with MUFA (g/100 g fatty acids) in men, indicating that the excess of fat intake in obesity is due to a larger consumption of olive oil. CVRF were significantly and positively associated to waist circumference and WHR, both in obese and in normal-weight subjects. In conclusion, not only obesity but also android fat in normal-weight subjects are important factors in cardiovascular disease even in the Mediterranean population, with a high intake of MUFA, where these factors seem to be more relevant to cardiovascular risk than dietary composition.

Effect of protein hydrolysis on the dialysability of amino acids and minerals in infant formulas

The objectives of this study were to evaluate the dialysed quantities of amino acids and minerals (calcium, phosphorus, magnesium, iron and zinc) in two types of infant formulas, one with a basis of native cow milk proteins and the other highly hydrolysed, to evaluate the possible application of Miller's in vitro method in amino acid and mineral availability studies. The percentage of dialysis differed between proteins. The hydrolysis treatment applied to the proteins significantly increased the dialysis percentage of almost all the amino acids. The dialysability of all the minerals was statistically greater in the formula made with a basis of hydrolysed proteins. Miller's method was seen to be of use for showing the effect which the hydrolysis treatment has on the availability of amino acids. Despite its limitations of having to be carried out in vitro, the study suggests that the nutritional value in relation with amino acids, minerals and trace elements differs between the both types of formulas.

Body fat distribution in pre-and post-menopausal women: metabolic and anthropometric variables

BACKGROUND

Abdominal obesity is associated with coronary risk although the causality is not well established.

OBJECTIVE

To compare body fat distribution and metabolic variables in obese pre- and post- menopausal women.

DESIGN

The study was conducted in 55 obese female subjects (22 pre- and 33 post- menopausal) with body mass indices (BMI) from 27 to 35 Kg/m2. Body fat distribution was measured using waist and hip circumference and computerized tomography. Hormones such as estradiol, testosterone, androstenedione, dehydroepiandrosterone-sulfate, as well as plasma lipids such as triglycerides, total cholesterol, high density lipoprotein, low density lipoprotein, apoproteins A and B, were also determined.

RESULTS

No significant differences were found between the two groups in BMI, percentage of body fat, waist circumference, triceps, biceps, suprailiac and abdominal skinfolds. Hip circumference, subscapular skinfold and subcutaneous abdominal adipose tissue area were significantly lower, and waist-hip ratio, visceral area and visceral to subcutaneous area ratios significantly higher in post- menopausal women (P < 0.05). As was expected, basal plasma estrogens, and dehydroepiandrosterone-sulfate, were significantly higher in pre-menopausal women. When comparing plasma lipids, blood cholesterol and low density lipoprotein, values were significantly higher in the post-menopausal group (P < 0.05).

CONCLUSIONS

Our data suggest that body fat distribution changes according to menopausal status, with central obesity more pronounced in post- menopausal women. Metabolic abnormalities are related more to visceral adipose tissue and estrogen plasma levels than to BMI.

Interrelationship between serum lipid profile, serum hormones and other components of the metabolic syndrome

The aim of the present study was to investigate the association between the serum lipid profile and components of the metabolic syndrome, such as central obesity (anthropometric, computed tomography and fat cell data), insulin, sex-hormone-binding-globulin (SHBG) and different hormones influencing this important syndrome, e.g. sex steroids, leptin and tumor necrosis factor-alpha (TNF-alpha). The sample consisted of 85 obese patients (30 men and 55 women) who had undergone abdominal surgery. Fasting serum lipids were analysed, as well as anthropometric and computed tomography data, perivisceral and subcutaneous fat cell size and serum glucose and hormones. Abdominal fat revealed itself as an important correlator of the adverse changes in plasma lipoprotein levels, the waist-to-hip-ratio and waist-to-thigh-ratio being the best morphological correlators in men and women, respectively. Intra-abdominal fat (VA) correlated significantly and positively to perivisceral fat cell size in women, while no correlation was found between subcutaneous fat accumulation (SA) and adipocyte size in both genders. Perivisceral fat cell size showed the greatest number of correlations with the adverse plasma lipid profile compared to that in the subcutaneous depot. SHBG and sex steroids showed a negative correlation with serum lipids considered a cardiovascular risk. In contrast, TNF-alpha and C-peptide were inversely correlated with potential protector lipids. In conclusion, abdominal obesity, adipocyte hypertrophy from visceral fat, serum TNF-alpha and C-peptide seem to be the best correlators of the lipoprotein disturbance characteristic of the metabolic syndrome, whereas SHBG and sex steroids could play a protective role regarding the lipid profile associated to this syndrome.

Effects of intense exercise training on rainbow trout growth, body composition and metabolic responses

Cultured fish are bound to experience a variety of potentially stressful situations. In principle, stress may be reduced by adapting fish to intense exercise. This article addresses the effects of chase-induced intense exercise training on rainbow trout. Training reduced fish growth and worsened their nutritional use of food, but had no effect on food intake, biometry or body composition, indicating that a significant fraction of the diet's energy was being used for exercising rather than growth. Regarding metabolic responses, training significantly counterbalanced lactate, glucose and cortisol plasma concentration increases induced by intense exercise, while completely abolishing that of plasmatic proteins. These data suggest that this type of training adversely affects fish growth and food conversion, whereas it improves their metabolic response capacity and reduces the stress component of forced exercise.

Influence of dietary protein type and iron source on the absorption of amino acids and minerals

The apparent digestibility coefficient (ADC) of amino acids and the balance of minerals (calcium, phosphorus, magnesium and iron) has been determined in rats fed four diets differing in the protein type (casein or soy protein) and iron source (ferrous sulphate or lactate) in order to study the possible interactions of these nutrients. The availability of amino acids, especially essential amino acids, was greater in the diet made with animal protein (casein). The iron source also affected the absorption of most amino acids in all the diets assayed with ferrous sulphate being greater. The balance of iron, magnesium and phosphorus was higher in the diets containing animal protein. The retention of calcium and magnesium was significantly greater when ferrous sulphate was used as iron source. These results demonstrate the important interaction between amino acids and minerals and between the minerals themselves, which must be carefully studied when selecting different types of protein or mineral sources in human or animal nutrition.

Dietary trans fatty acids in early life: a review

Trans fatty acids are unsaturated fatty acids with at least a double trans configuration, resulting in a more rigid molecule close to a saturated fatty acid. These appear in dairy fat because of ruminal activity, and in hydrogenated oils; margarines, shortenings and baked goods contain relatively high levels of trans fatty acids. These fatty acids can be incorporated into both fetal and adult tissues, although the transfer rate through the placenta continues to be a contradictory subject. In preterm infants and healthy term babies, trans isomers have been inversely correlated to infantile birth weight. However, in multigenerational studies using animals, there is no correlation between birth weight, growth, and dietary trans fatty acids. Maternal milk reflects precisely the daily dietary intake of trans fatty acids, from 2% to 5% of the total fatty acids in human milk. The level of linoleic acid in human milk is increased by a high trans diet, but long-chain polyunsaturated fatty acids remain mostly unaffected. Likewise, infant tissues incorporate trans fatty acids from maternal milk, raising the level of linoleic acid and relatively decreasing arachidonic and docosahexaenoic acids. This suggests an inhibitory effect of trans fatty acid on liver Delta-6 fatty-acid desaturase activity. As opposed to blood and liver, the brain appears to be protected from the trans fatty-acid accumulation in experimental animals, but no data have yet been reported for human newborns. Further investigations in humans are needed to definitively establish the potential physiological consequences of trans fatty-acid intake during the neonatal period.

Site-specific differences in the fatty acid composition of abdominal adipose tissue in an obese population from a Mediterranean area: relation with dietary fatty acids, plasma lipid profile, serum insulin, and central obesity

BACKGROUND

Abdominal obesity is associated with coronary risk, although causality is not well established.

OBJECTIVE

In an obese Mediterranean population, we measured the fatty acid composition of adipose tissue, its relation with dietary fatty acids and central fat deposition, and its influence on plasma lipids and insulin.

DESIGN

Adipose tissue samples were obtained from 84 obese patients (29 men, 55 women) aged 30-70 y (body mass index, in kg/m(2): 27-35). We measured concentrations of insulin and lipids in plasma and fatty acids in subcutaneous, omental, and perivisceral fat. Dietary fatty acid intake was assessed with a 7-d diet record.

RESULTS

The population studied was normolipidemic and normoinsulinemic. There were important differences in fatty acid composition between tissue sites: saturated fatty acids were higher and monounsaturated fatty acids were lower in perivisceral than in subcutaneous fat (P < 0.05). Significant correlations were found for oleic, linoleic, alpha-linolenic, and total n-6 polyunsaturated fatty acids between the subject's habitual diet and adipose tissue composition. Oleic and n-3 fatty acids from adipose regions were negatively correlated with apolipoprotein B and triacylglycerols; adipose tissue 22:1n-9, 20:2n-6, stearic acid, and eicosapentaenoic acid were positively correlated with HDL and apolipoprotein A; and adipose tissue myristic acid was negatively correlated with apolipoprotein A (P < 0.05). Central obesity was positively associated with n-6 polyunsaturated fatty acids and inversely associated with monounsaturated fatty acids and n-3 polyunsaturated fatty acids in adipose tissue (P < 0.05).

CONCLUSION

The differences found in the composition and metabolism of perivisceral, omental, and subcutaneous fats may indicate that their atherogenic capacities also differ.

[In vitro availability of minerals in infant foods with different protein source]

As the result of the digestion process, it is produced at gastrointestinal level interactions between proteins-minerals and minerals-minerals that might modify the bioavailability of the nutrients initially designed for an adequate nutrition in infant formulas. The aim of the present study is to compare the in vitro availability of some minerals and trace elements (calcium, phosphorus, magnesium, iron and zinc) in infant formulas of initiation elaborated with different protein sources: formulas based on cow milk protein (whey-casein) versus vegetal protein (soy-based infant formulas). Also, for evaluating the effects of the different mineral supplementation in the availability of minerals, it was used infant formulas from two different manufacturers. Milk-protein based infant formulas showed for both manufacturers higher dialysis percentage (%) of phosphorus and zinc than the soy-protein based formulas. The availability of iron in the soy formula of the manufacturer A lowered significantly (P < 0.05) respect to the whey-casein based formula (9.6 +/- 2.3 versus 4.6 +/- 0.8), but not respect to the whey-casein formula of manufacturer B (9.6 +/- 1.1 versus 9.0 +/- 0.7), which might be due to the lowest proportion of phytic acid in this last commercial formula. Dialysability of all the minerals analysed from soy-protein based formulas showed significant differences depending on the manufacturer. The purification processes of the soy protein have a high repercussion in the mineral availability of soy-based infant formulas. It could be more interesting to use soy proteins more purified, with low level of phytic acid, in the elaboration of soy infants formulas, than the supplementation them with high amounts of minerals.

Usefulness of procalcitonin and C-reactive protein rapid tests for the management of children with urinary tract infection

BACKGROUND

Urinary tract infection (UTI) is a common problem in children. Because clinical findings and commonly used blood indices are nonspecific, the distinction between lower and upper urinary tract infection cannot be made easily in this population. However, this distinction is important because renal infection can induce parenchymal scarring. The objective of this study was to determine the accuracy of procalcitonin (PCT) compared with C-reactive protein (CRP) rapid tests to predict renal involvement in children with febrile UTI.

METHODS

PCT and CRP were measured in the blood of children admitted to the emergency room with fever, signs and symptoms of urinary tract infection and/or a positive urine dipstick analysis. Renal parenchymal involvement was assessed by a 99mTc-labeled dimercaptosuccinic acid renal scan in the acute phase of infection in all children. Sensitivity, specificity and likelihood ratios were determined for both tests.

RESULTS

Fifty-four children with a proven urinary tract infection were enrolled: 63% had renal involvement; and 37% had infection restricted to the lower urinary tract. No difference was found for age, sex and total white blood cell count between the groups. The calculated likelihood ratios of procalcitonin and C-reactive protein rapid tests were between 3.8 and 7 and 1.5 and 2.8, respectively. A positive PCT value predicted renal involvement in 87 to 92% of children with febrile UTI, compared with 44 to 83% using CRP values.

CONCLUSIONS

A rapid determination of procalcitonin concentration could be useful for the management of children with febrile UTI in the emergency room.

Salvage of avascular bone from frostbite with free tissue transfer

Traditional management of frostbite injury of the hands and fingers has been to allow demarcation to occur between viable and nonviable tissues, corresponding to the level of amputation required. In this case report, phalangeal length in mummified digits was maintained with free tissue transfer followed by evidence of bony revascularization on bone scan. Rather than waiting for tissue demarcation to occur, the authors propose that consideration be given to debridement of soft tissues in the frostbitten fingers followed by free tissue transfer to salvage length and function in the digital bony skeleton.

Endocrine, metabolic and nutritional factors in obesity and their relative significance as studied by factor analysis

OBJECTIVE

To evaluate different aspects of obesity, such as body fat distribution, plasma hormone and lipid profiles, adipose tissue composition and dietary intake in an obese population in order to identify the most important factors that contribute to obesity.

DESIGN

Eighty-five obese subjects, 30 men and 55 women (age, 30-70 y; body mass index (BMI), 27-35 kg/m2), were studied using anthropometric measurements, computed tomography, adipose tissue composition, serum hormone and lipid profiles and nutritional evaluations. To determine to what extent individual factors contributed to the general process of obesity, the data were subjected to a factor analysis.

RESULTS

Three patterns of anthropometric and computed tomography data emerged that accounted for 69% of the variance. Factor 1 defined abdominal obesity and explained 30% of the total variance, factor 2 (gynoid obesity) accounted for 26%; and factor 3 (subcutaneous fat) explained 13% of the total variance. When other factors associated with obesity, such as lipid profile, hormonal profile and fat composition, were introduced, obesity itself, especially abdominal obesity, remained the principal factor, accounting for 23% of total variability. All factors were of secondary importance when dietary characteristics were introduced. In the overall factor analysis, more than 40% of the variability in obesity was related to dietary habits, particularly fat intake, followed by energy and saturated fatty acids intake.

CONCLUSION

Even though obesity is a multifactorial phenomenon, the results suggest that dietary intake, especially fat intake, is the most important factor contributing to obesity. Secondary factors include endocrine and metabolic factors.

[Colonization by Ureaplasma urealyticum and chronic lung disease in premature newborn infants under 32 weeks of gestation]

Colonization of the respiratory tract of premature newborn infants by genital mycoplasma is suspected to be associated with chronic lung disease.

METHODS AND PATIENTS

We prospectively determined the prevalence of genital mycoplasma colonization with nasopharyngeal or endotracheal culture in preterm neonates younger than 32 weeks gestation and its possible association with the development of chronic lung disease in a prospective study.

RESULTS

Fifty-nine infants were enrolled and 11 (19%) were colonized with Ureaplasma urealyticum. In the subgroup of 45 ventilated infants, seven of seven U. urealyticum-positive infants developed chronic pulmonary disease versus ten of 38 (26%) of U. urealyticum-negative infants (relative risk [RR] = 3.8; 95% confidence interval [CI] 2.2 to 6.5, P < 0.001). U. urealyticum-colonized infants had a lower median birth weight (760 vs 1,083 g, P = 0.04), a lower gestational age (26 vs 28 weeks, P = 0.03), and a higher incidence of symptomatic patent ductus arteriosus (P = 0.03). These potential confounding factors may partially explain the association between U. urealyticum and chronic pulmonary disease. However, this association remained statistically significant when the analysis was restricted to infants with birth weight of 1,000 g or less (RR = 2.3; 95% CI 1.3 to 4, P = 0.02) or to infants with a patent ductus arteriosus (RR = 2; 95% CI 1.3 to 3.1, P = 0.02).

CONCLUSION

Colonization with U. urealyticum in ventilated preterm neonates younger than 32 weeks gestation is a significant risk factor of developing chronic pulmonary disease.

Anthropometric, computed tomography and fat cell data in an obese population: relationship with insulin, leptin, tumor necrosis factor-alpha, sex hormone-binding globulin and sex hormones

OBJECTIVE

To correlate anthropometric, computed tomography and fat cell data from abdominal regions with the levels of serum insulin, C-peptide, leptin, tumor necrosis factor-alpha (TNF-alpha), testosterone, 17beta-estradiol, androstenedione, dehydroepiandrosterone sulphate (DHEA-S) and sex hormone-binding globulin (SHBG).

DESIGN AND METHODS

The sample consisted of 84 obese patients (29 men, 22 premenopausal women and 33 postmenopausal women) who had undergone abdominal surgery. Weight, height, percentage of body fat by skinfolds, waist, hip and thigh circumferences, sagittal and coronal diameters, visceral and subcutaneous area, serum hormones and fat cell data were studied.

RESULTS AND CONCLUSIONS

Premenopausal women showed the lowest values in most abdominal distribution parameters, although, depending on the waist circumference criteria at the umbilicus level perimeter (W1) or midway between lower rib margin and iliac crest perimeter (W2), the population was classified differently, as gynoid or android. Although there were no differences in fat cell size between genders, gynoid women had smaller and more numerous fat cells than the android type. Perivisceral fat cell size was significantly smaller than subcutaneous fat cell size. In women, central obesity was significantly correlated with an increase in serum insulin, leptin, TNF-alpha, testosterone and androstenedione levels, and a decrease in 17beta-estradiol and DHEA-S, while in men significant correlations were positive with insulin and negative with testosterone and androstenedione. Fat cell size was positively correlated with serum levels of leptin, insulin, DHEA-S, androstenedione and inversely correlated with SHBG. These data indicate that hormones seem to interact not only with body fat distribution but also with fat cell size. This interaction differs between genders and between the different abdominal adipose tissue regions.

Self-design of fish diets by means of self-feeders: validation of procedures

In this paper, we show the results from four different experiments in which sea bass, maintained under laboratory conditions, could choose between two or three different diets through self-feeders, which gradually increased the complexity and potential range of selection, to design their own diet in accordance with their requirements. At first, sea bass were allowed to select between two complete diets differing in the proportion of protein (52-58%): this showed their capacity to distinguish between two diets made of the same ingredients. Next, two incomplete diets, containing a fixed amount of protein (56%) and lacking either fat or carbohydrate, were made available. Three mixed diets made up of pairs of macronutrients (protein-carbohydrate, protein-fat or fat-carbohydrate) were tested in the next experiment and, finally, three diets containing only one macronutrient (protein fat or carbohydrate) were made available to fish. Taking into account selection made by the fish in the first three experiments, in which macronutrient selection was statistically different, protein was the main macronutrient chosen by fish (278.15 kJ/kgBW/day, on average), followed by fat and carbohydrate (162.85 and 64.56 kJ/kgBW/day, respectively). In conclusion, the results reveal the ability of sea bass to select an appropriate diet from experimental diets containing two or three macronutrients and suggest that the proposed methodology is a powerful tool for studying the differing nutritional needs of different species of fish.

Dietary trans fatty acids affect the essential fatty-acid concentration of rat milk

Increasing efforts have been made to determine the distribution and concentration of trans fatty acids in milk, due to the importance of lipids in infant growth and development. In general, trans fatty acid concentration of milk reflects trans fatty acid intake, but insufficient data are available to assess the effects of dietary trans fatty acids on maternal milk. Thus, controlled studies are needed to establish whether there is a dose-response relationship and whether trans fatty acids could affect the concentration of essential fatty acids (EFA), long-chain polyunsaturated fatty acids (PUFA) and the (n-6)/(n-3) ratio in milk. Three groups of six rats each were fed for 10 wk one of three diets differing in trans fatty acid concentration (Control, 0 mol/100 mol; high trans concentration (H), 14.5 mol/100 mol; very high trans concentration (VH), 30 mol/100 mol), but containing the same proportions of linoleic and alpha-linolenic acids and a ratio of 18:2(n-6)/18:3(n-3) of about 7:1. Trans fatty acids were incorporated into maternal milk in a dose-dependent manner. In addition, rats fed trans isomers had greater linoleic acid levels than controls. The proportion of alpha-linolenic acid in milk was lower in the VH group, and the (n-6)/(n-3) cis PUFA ratio in milk of the VH group was greater than that in controls. Total long-chain PUFA levels did not differ among groups. These results suggest that high intakes of trans fatty acids affect the EFA concentration but not that of long-chain PUFA of rat milk, provided that EFA are supplied in sufficient amounts.

Dietary intake in adolescents from south-east Spain and its relationship with physical activity

Dietary intake (energy, macronutrients and micronutrients) and its possible relationship with levels of physical activity were studied in an adolescent group consisting of 142 boys and 197 girls aged between 14-18 years, from the region of Murcia. A continuous, 7 day dietetic register was used, and the population was stratified by physical activity (low, medium and high) and by sex. Results show an excess of energy in the diets of the male group, concurring with tricipital fold measurements, which were higher than the mean value for the Spanish adolescent population. A significant negative relationship was found (P < 0.05) between levels of physical activity and body fat content in the female group. Lipid excess and carbohydrates deficit were the principal dietetic imbalances found. Micronutrient deficits were observed in vitamin E, iron, zinc and magnesium. Although the study does not reveal significant differences in the alimentary habits of active and sedentary adolescents, the beneficial effects of exercise can be considered to partly compensate the dietetic imbalances found.

Difference in dietary intake and activity level between normal-weight and overweight or obese adolescents

BACKGROUND

To investigate the prevalence of overweight and obesity in an adolescent group representative of a rural Mediterranean area and to determine possible associations with energy and nutrient intakes and levels of physical exercise.

METHODS

A representative sample of adolescents was drawn from the secondary school of Torre Pacheco (Murcia), a rural Mediterranean area located in the southeast of Spain. The population selected (331 adolescents aged 14-18 years), was divided into two groups: normal-weight subjects with a body mass index less than 23 kg/m2 and overweight or obese subjects with a body mass index of 23 kg/m2 or more. Weight, height, abdominal and hip perimeters, triceps skinfold, and upper arm circumference were measured. A prospective 7-consecutive-days food record and physical activity questionnaire were completed.

RESULTS

Overweight boys and girls had an apparently lower energy intake (P = 0.001 and P = 0.042, respectively), and carbohydrate intake (P = 0.000, P = 0.032) than their normal-weight counterparts, but they tended to underreport more often. Overweight boys derived a greater percentage of their energy from fat (P = 0.049) and less from carbohydrate (P = 0.016) than their normal-weight counterparts. Among girls, the percentage of energy derived from fat increased with body mass index (r = 0.210, P = 0.008), whereas fiber intake decreased (r = -0.145; P = 0.041). Overweight and obesity were negatively related to physical activity level only among boys (P = 0.033).

CONCLUSION

There is a high prevalence of overweight and obesity in the adolescent population studied (48.2% in boys and 30.7% in girls). The study shows an association between overweight and obesity and nutrient intake and activity level.

Dietary trans fatty acids affect docosahexaenoic acid concentrations in plasma and liver but not brain of pregnant and fetal rats

The aim of the present study was to investigate the maternal-fetal transport, incorporation, and effects on liver delta-6 fatty-acid desaturase activity of dietary trans fatty acids in pregnant rats. Three groups of six rats each were fed three experimental diets containing approximately 0%, 15%, and 30% of trans fatty acids but containing the same proportion of linoleic (18:2 n-6) and a-linolenic (18:3 n-3) acids for 10 wk. On d 20 of pregnancy, the animals from each group were killed. We determined the fatty acid profiles in plasma, brain, and liver microsomes of pregnant rats, as well as in placenta and fetal liver and brain. No changes were found in the number of fetuses of the pregnant rats. Trans fatty acids were incorporated in high concentrations in placenta and in maternal and fetal tissues, except brain, strongly elevating the linoleic acid proportion and lowering that of docosahexaenoic acid. The delta-6 fatty-acid desaturase activity in the liver microsomes of the pregnant rats was inhibited by trans isomers. In conclusion, high intakes of trans fatty acids partially inhibit liver delta-6 fatty-acid desaturase in pregnant rats, which may explain, in part, the low concentrations of docosahexaenoic acid in pregnant and fetal tissues. However, the fatty acid composition of both fetal and pregnant rat brain remains mostly unaffected regardless of the dietary trans fatty acid content.

Influence of exercise on plasma and muscle free amino acids in trained rainbow trout

Variations in the concentration of free amino acids in the muscle and plasma of trout submitted to 5 minutes of intense exercise have been studied. The responses of untrained fish and those trained performing the same type of exercise twice daily for 28 days are compared. Total amino acid concentrations in muscle tend to diminish after intense exercise. Significant decreases are observed in muscle content of alanine, beta-alanine, isoleucine and ornithine. Plasma amino acids tend to increase after exercise with significant differences in glutamate, GABA, methionine and NH4+. The small variations due to intense exercise suggest that the amino acids are mobilised. Training led to a decrease in total amino acid concentration in plasma but not in muscle, where levels of aspartate and ornithine increased. This suggests a metabolic adaptation to exercise, with amino acid level retention in the muscle.

Food entrainment to 4-h T cycles in rats kept under constant lighting conditions

The effect of 4-h feeding cycles on the feeding pattern of rats kept under constant light and constant darkness, was analysed. In both cases, the scheduled pattern of food-approach behavior elicited dissociation of the feeding activity into several components associated to the feeding times (CAFT), which coexisted with the previous circadian free-running rhythms. In LL rats and in the rest phase of DD animals, the CAFT was characterized by an increased number of food approaches confined exclusively to the period of food availability, with poor anticipatory activity. However, in the active phase of some DD rats, CAFT included an additional anticipatory activity. The interaction between the CAFT and the free-running rhythms involved modulation of the CAFT, depending on the free-running periodicity. After termination of the feeding-restriction schedule, some DD and LL animals retained the CAFT for at least 3 days. However, when the access to food was blocked 10 days after ending the restricted schedule, rats did not show any feeding activity associated to the previous feeding times. A spontaneous feeding pattern similar to that imposed by the previous feeding schedule emerged immediately after food deprivation in two of the DD animals. Although these results are compatible with the existence of a food-entrainable pacemaker, the existence of a multioscillatory light-entrainable pacemaker with some oscillators entrained by food pulses and others free-running may explain our results.

Food-entrained feeding and locomotor circadian rhythms in rats under different lighting conditions

It has been suggested that two endogenous timekeeping systems, a light-entrainable pacemaker (LEP) and a food-entrainable pacemaker (FEP), control circadian rhythms. To understand the function and interaction between these two mechanisms better, we studied two behavioral circadian rhythmicities, feeding and locomotor activity, in rats exposed to two conflicting zeitgebers, food restriction and light-dark cycles. For this, the food approaches and wheel-running activity of rats kept under light-dark (LD) 12:12, constant darkness (DD), or constant light (LL) conditions and subjected to different scheduled feeding patterns were continuously recorded. To facilitate comparison of the results obtained under the different lighting conditions, the period of the feeding cycles was set in all three cases about 1h less than the light-entrained or free-running circadian rhythms. The results showed that, depending on the lighting conditions, some components of the feeding and wheel-running circadian rhythms could be entrained by food pulses, while others retained their free-running or light-entrained state. Under LD, food pulses had little influence on the light-entrained feeding and locomotor rhythms. Under DD, relative coordination between free-running and food-associated rhythms may appear. In both cases, the feeding activity associated with the food pulses could be divided into a prominent phase-dependent peak of activity within the period of food availability and another afterward. Wheel-running activity mainly followed the food pulses. Under LL conditions, the food-entrained activity consisted mainly of feeding and wheel-running anticipatory activity. The results provide new evidence that lighting conditions influence the establishment and persistence of food-entrained circadian rhythms in rats. The existence of two coupled pacemakers, LEP and FEP, or a multioscillatory LEP may both explain our experimental results.

Annual rhythms of demand-feeding activity in sea bass: evidence of a seasonal phase inversion of the diel feeding pattern

Seasonal changes in the phasing of diel feeding rhythms were investigated in sea bass held under natural conditions. Demand-feeding behavior was continuously monitored over a complete annual cycle in 10 groups of 15 fish maintained in an outdoors laboratory subjected to natural fluctuations of photoperiod (from 9.5h to 15h) and water temperature (from 13.2 degrees C to 27.4 degrees C). A double seasonal phase inversion was detected in all groups: fish that were diurnal in summer and in autumn changed to nocturnal in winter and returned to being diurnal in spring. Diurnal sea bass displayed a positive and stable phase relationship between the peak of the feeding phase and the daily acrophase of water temperature (phi l = 0.72h +/- 0.33h) and between the peak of the feeding phase and sunset (phi s = 2.94h +/- 0.53h), but both phi l and phi s became negative when sea bass shifted to nocturnalism in winter. The percentage of diurnal feeding behavior peaked in June (94.1%) and dropped in February (29.1%), following a cyclic dynamic modulated by both monthly photoperiod and water temperature. These results contribute to better understanding of the dual phasing behavior of sea bass, which exhibits diurnal or nocturnal behavior according to the time of the year so that flexibility in phasing may be advantageous for the fish to cope with seasonal changes in their environment.