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PubMed2005

Differential role of the accumbens Shell and Core subterritories in food-entrained rhythms of rats.

Restricted feeding schedules (RFS) entrain behavioral and physiological rhythms even in suprachiasmatic nucleus ablated animals, suggesting the existence of a food-entrained oscillator. The nucleus accumbens is an important structure for the expression of motivational behaviors and because its anatomical subterritories, Shell (Acc-Sh) and Core (Acc-Co) establish connections with different functional systems, they may participate in a differential way in food-entrainment. A first experiment, explored the role of Acc-Sh and Acc-Co in food-entrainment using the immunohistochemical detection of the protein c-Fos as a transcriptional activation marker. Experiment 2 tested the differential effect of Acc-Sh and Acc-Co, NMDA excitotoxic lesions. Lesioned rats were entrained to RFS and locomotor activity and free fatty acids (FFA) concentrations were evaluated. Results data show that in the Acc-Sh there is an increase of c-Fos immunoreactivity in food-entrained rats principally during feeding, whereas c-Fos expression in the Acc-Co region was increased during feeding and also anticipating mealtime. FFA were entrained in both lesioned groups, but the basal level was lower in Core-lesion rats. All rats exhibited food anticipatory activity (FAA). However, FAA was increased in Shell-lesioned animals and was almost abolished in the Core-lesion rats. These data indicate that the accumbens nucleus is involved with behavioral and metabolic food-entrainment, and that there is a differential role between both subregions.

Animals↗
PubMed1999

Solution structure of a new hypothalamic neuropeptide, human hypocretin-2/orexin-B.

Orexin-A and orexin-B (also called hypocretin-1 and hypocretin-2, respectively) are novel hypothalamic neuropeptides encoded by a single mRNA transcript; they stimulate food intake. We have determined the three-dimensional solution structure of human hypocretin-2/orexin-B using two-dimensional 1H-NMR data and dynamical simulated annealing calculations. On the basis of NOEs, 3JHNalpha coupling constants and hydrogen-deuterium exchange rates together with chemical shift indices, human hypocretin-2/orexin-B was deduced to consist of two alpha-helices connected with a short linker in both H2O and 30% trifluoroethanol solutions. The helical axis of helix I is oriented about 60-80 degrees relative to helix II. Hybrid distance geometry and simulated-annealing protocols were used to generate an ensemble of 30 structures with no constraint violations greater than 0.03 nm for distances and 3 degrees for angles. In addition, human hypocretin-2/orexin-B shares a similar secondary-structural motif with human neuropeptide Y. This result can form the basis for further study on ligand-receptor recognition of human orexin receptors.

Amino Acid Sequence↗
PubMed2005

Polyphenols in foods are more complex than often thought.

Dietary polyphenols show a great diversity of structures, ranging from rather simple molecules (monomers and oligomers) to polymers. Higher-molecular-weight structures (with molecular weights of > 500) are usually designated as tannins, which refers to their ability to interact with proteins. Among them, condensed tannins (proanthocyanidins) are particularly important because of their wide distribution in plants and their contributions to major food qualities. All phenolic compounds are highly unstable and rapidly transformed into various reaction products when the plant cells are damaged (for instance, during food processing), thus adding to the complexity of dietary polyphenol composition. The polyphenol composition of plant-derived foods and beverages depends on that of the raw material used but also on the extraction process and subsequent biochemical and chemical reactions of plant polyphenols. The occurrence of specific tannin-like compounds (ie, thearubigins and theaflavins) arising from enzymatic oxidation is well documented in black tea. Various chemical reactions involving anthocyanins and/or flavanols have been demonstrated to occur during red wine aging. Current knowledge regarding the reaction mechanisms involved in some of these processes and the structures of the resulting products is reviewed. Their effects on organoleptic and nutritional quality are also discussed.

Flavonoids↗
PubMed1991

Serum cholesterol increase in a middle-aged male industrial population during ten years (1976-1986) and general food consumption changes in Czechoslovakia.

The authors evaluate the coronary risk factor changes in middle-aged men from the point of view of changed nutritional habits of the whole population (yearly per capita consumption of different food). They compared 3,754 men aged 40-50 years when screened in 1976-77 (Skoda I Study) and 568 men aged 40-50 years when screened in 1986-88 (Skoda II Study). During the 10-year period, a significant decrease of smoking habits was observed, hypertension prevalence remained unchanged and hypercholesterolaemia prevalence increased significantly. The estimated yearly per capita consumption of meat and fat remained unchanged in the years 1975-1985, however, the structure of consumption revealed a gradual change towards food containing high amounts of animal fat. Education efforts during the 10-year period (1976-1986) led to a decrease in smoking habits in middle-aged men leaving hypertension control unchanged. The observed increase of cholesterol levels may be attributed to inappropriate nutritional habits gradually worsening in the whole population probably due to a socio-economic depression.

Adult↗
PubMed2002

Isopod gut microflora parameters as endpoints in toxicity studies.

Terrestrial isopods Porcellio scaber (Crustacea) were fed for five weeks on food contaminated by 250, 500, or 1,000 microg of Cd/g or for 10 d on diets with 50 or 250 microg Cd/g food. In both experiments, fecal production rate and colony forming units (CFUs) in the guts were determined. In addition, at the end of 10 d, each distinct colony morphotype obtained in gut samples was purified and characterized. Isolates were separated into 25 groups based on morphological and biochemical characteristics. These bacterial groups were used as units for calculating Shannon equitability indices (J) for each gut. The relative frequencies of the 25 bacterial units were determined in both cadmium groups (50 or 250 microg Cd/g food) and in the control. Cadmium-induced perturbations observed in the gut microbial communities were (1) increased number of morphologically distinct bacterial isolates in the group fed low-cadmium-dosed food (50 microg Cd/g) and reduced number of morphologically distinct bacterial isolates in the group fed high-cadmium-dosed food (250 microg Cd/g) compared with the control, (2) increased or decreased relative frequencies of almost all 25 bacterial units provoked by cadmium-contaminated food, (3) time-dependent increased numbers of gut CFUs in cadmium-fed animals (dose dependence was not observed), and (4) significant changes in community structure described by Shannon equitability indices at lower levels of food contamination (50 microg Cd/g) only. Gut microflora parameters are proposed as additional endpoints in the standardized single-species toxicity test with the terrestrial isopod P. scaber as a means of increasing the ecological relevance of the results.

Administration, Oral↗
PubMed1996

Food choice: a conceptual model of the process.

Interviews examining the food choice process were conducted with 29 adults, primarily individuals making grocery store food choice decisions, who were sampled for their diversity. These people were asked about how they chose foods when shopping and in other settings, and what influenced their choices. Verbatim transcripts of the interviews were analysed using qualitative methods that included constant comparison, concept mapping, and case summaries, and a conceptual food choice process model was developed. Data from the interviews are presented to illustrate the structure of this conceptual model. People's life course experiences affected major influences on food choice that included ideals, personal factors, resources, social contexts and the food context. These influences informed the development of personal systems for making food choices that incorporated value negotiations and behavioral strategies. Value negotiations weighed sensory perceptions, monetary considerations, health and nutrition beliefs and concerns, convenience, social relationships and quality of food choice decisions. Strategies employed to simplify the food choice process developed over time. The conceptual food choice process model represents the rich and complex bases of food practices, and provides a theoretical framework for research and practice in nutrition.

Adult↗
PubMed1993

Dietary supplementation: the case for placebo-controlled trials.

There are a variety of ways in which we learn about the relationship of diet to cancer prevention or cancer etiology in humans. Epidemiologic studies provide the basis for many of our hypotheses, while animal studies provide opportunities to try out more specific models. However, only human clinical trials can adequately test these concepts and identify which food compounds are related to cancer prevention. Further, clinical trials can provide opportunities to examine underlying mechanisms. Clinical trials in the area of diet and cancer prevention have largely been of two types: single (or dual) nutrients (purified, in high-dose pills) tested in double-blind placebo-controlled trials, and randomized dietary interventions, using education of the subjects to achieve broad scale dietary change. This paper argues for an intermediate form of clinical trial, using a food-based supplement in a randomized double-blind placebo-controlled design. This model is particularly appropriate for studying food components such as fiber for which the activity may rely on higher order structure.

Clinical Trials as Topic↗
PubMed2003

The evolutionarily conserved gonadotropin-releasing hormone II modifies food intake.

GnRH is an evolutionarily conserved peptide of which there are multiple structural variants. One form, GnRH II, is the most widespread in vertebrates, but its primary function remains unclear. In female musk shrews, administration of GnRH II, but not GnRH I, reinstates mating behavior previously inhibited by food restriction. Because this finding suggests that the function of GnRH II may be linked to energetic status, we tested whether GnRH II directly affects food intake. Adult female musk shrews were maintained on ad libitum feeding or food restricted for 48 h, after which they were infused centrally with GnRH I (1 microg), GnRH II (1 microg), or saline. Food intake was recorded 90 min, and 3, 6, 24, and 48 h after infusion. GnRH II administration, but not saline or GnRH I, reduced 24-h food intake in ad libitum animals. Short-term food intake (90 min and 3 h) of both ad libitum and underfed shrews receiving GnRH II was also reduced by as much as 33%, relative to the food intake of saline-infused controls. GnRH I infusion did not affect short-term food intake differently than saline infusion in shrews fed ad libitum. In underfed females, GnRH I had an effect on short-term food intake that was intermediate to saline and GnRH II. We conclude that, in addition to its permissive role in regulating reproduction, GnRH II may also modulate food intake in mammals. Because GnRH II is present in primate brain, it may also serve a similar function in humans.

Animals↗
PubMedDate not supplied

The Nuer Nutrition Education Program: breaking down cultural barriers.

Very little is known about the Nuer culture, partly because of its widely misunderstood language and because of the mixture of its people with the other tribes in Africa, according to Evans-Pritchard). However, it is known that the Nuer women's roles in the family seem to be centered around cooking duties. In the Nuer culture, no work is considered degrading, and the women know and accept their domestic duties. During the summer of 1996, a pilot project was conducted as an attempt to help Nuer refugee women of Des Moines, Iowa, incorporate nutritional concepts and American food preparation techniques into their existing methods of food preparation. The barriers faced involved the Nuer women's unfamiliarity with American foods and household items and their inability to read and understand English. Cultural issues and barriers were overcome when the health educator was willing to take the time to gain the trust and respect of the Nuer people. Structured interviews indicated an increase in knowledge of American foods and cooking skills. This education program in no way meant to replace traditional Nuer cooking methods; rather, it acted as a way to adjust to life in the United States.

Acculturation↗
PubMed1996

Computer model of a bovine type I collagen microfibril.

Collagens are a family of structural proteins of the extracellular matrix. The fibril-forming collagens are the major structural proteins of skin, cartilage, bone, blood vessel walls and internal organs. In addition to biological function, the collagens provide natural structural frameworks that are utilized in the medical, food and leather industries. Many schemes for the organization of type I collagen into triple helices, microfibrils and fibrils have been proposed during the past 30 years. Here, the development of a molecular model of a bovine type I collagen "Smith' microfibril is described. In cross-section, this model exhibits a symmetrical, pentagonal grouping of five triple helices. The model comprises 15 polypeptide chains having 315 residues each. This model is large enough to allow a comparison of its gross structural features with images of stained collagen obtained by electron microscopy, yet small enough to be manipulated on a minicomputer or work-station. The model is useful for (among others) studies of structure-function relationships in collagen, exploring folding pathways, predicting the efficacy of potential crosslinking agents or chemical modifications, and designing synthetic collagen-like materials or modifications for specific applications.

Amino Acid Sequence↗
PubMed2006

Delayed effects of larval predation risk and food quality on anuran juvenile performance.

Metamorphosis can disrupt the correlation structure between juvenile and adult traits, thus allowing relatively independent evolution in contrasting environments. We used a multiple experimental approach to investigate how diet quality and larval predation risk affected the rates of growth and development in painted frogs (Discoglossus galganoi), and how these changes influence post-metamorphic performance. A high-energy diet entailed growth advantages only if predation risk did not constrain energy acquisition, whereas diet quality affected primarily the extension of the larval period. Predation risk influenced juvenile shape, most likely via the effects on growth and differentiation rates. Juvenile frogs emerging from predator environments had shorter legs and longer bodies than those from the nonpredator tanks. However, these morphological changes did not translate into differences in relative jumping performance. Neither size-adjusted lipid storage nor fluctuating asymmetry was significantly influenced by food quality or predation risk. Our data suggest that the post-metamorphic costs of predator avoidance during the larval phase are mostly a consequence of small size at metamorphosis.

Animals↗
PubMed1987

A comparison of the effects of phenylpropanolamine, d-amphetamine and d-norpseudoephedrine on open-field locomotion and food intake in the rat.

d,l-Norephedrine (PPA) is available as an over-the-counter appetite suppressant and nasal decongestant in the U.S.A. The pseudoisomer d-norpseudoephedrine, is available as an appetite suppressant in Europe, and has been isolated as one of the stimulatory components (cathine) of the Khat plant. Some authors have misidentified cathine as PPA and this confusion in the literature has resulted. PPA and d-norpseudoephedrine possess significantly different pharmacological properties despite having identical structural formulae. Anorectic activity was determined in a food-deprived rat model. PPA and d-norpseudoephedrine were approximately one-tenth as potent as d-amphetamine with all compounds producing a dose-dependent decrease in food intake. Locomotor activity in an open-field apparatus was determined as an index of CNS stimulation. Male Sprague-Dawley rats treated with d-norpseudoephedrine, in doses between 10 and 50 mg/kg, exhibited significantly increased locomotor scores compared to saline (control) treated animals, an increase similar to that caused by 2 mg/kg d-amphetamine. PPA (5-50 mg/kg) failed to increase locomotion significantly. These results indicate that although each compound tested decreased food intake in a dose-dependent fashion, significant differences in open-field locomotion do exist between PPA, d-norpseudoephedrine, and d-amphetamine. Stereoisomeric compounds, although structurally similar, frequently have different pharmacological effects. Thus extreme care must be taken to properly identify these compounds in the literature.

Animals↗
PubMed2006

Lack of immunogenicity of ice structuring protein type III HPLC12 preparation administered by the oral route to human volunteers.

Before a novel protein can be used in foods, its potential allergenicity must be assessed. In this study, healthy volunteers consumed ice structuring protein (ISP) Type III preparation or a control material 5 days a week for a total of 8 weeks. General measures of health were recorded during the study, and the immunogenicity of the protein was assessed by monitoring the levels of IgG and IgE antibodies specific for ISP Type III. The participants remained in good health throughout the study and during the 4 week follow-up period. No IgG or IgE antibodies specific for ISP Type III were detected in the blood of the participants. Investigations of immunogenicity in man have not been previously applied in the context of safety evaluation and they do not form part of the regimens proposed for the evaluation of protein allergenicity. Consequently no standardised protocols exist for such studies, nor any background against which to interpret the results. Nevertheless, the absence of an immune response using a protocol which could have been expected to result in a response with a strongly immunogenic protein, confirms the conclusions of earlier published work, and attests to the lack of allergenicity of ISP Type III preparation.

Adjuvants, Immunologic↗
PubMed2001

Antioxidant mechanism of carnosic acid: structural identification of two oxidation products.

To determine the antioxidant mechanism of food phenolics against the oxidation of food components, the reaction of carnosic acid, an antioxidative constituent of the popular herbs sage and rosemary, was investigated in the presence of ethyl linoleate and the radical oxidation initiator 2,2'-azobis(2,4-dimethylvaleronitrile). During this process, carnosic acid was oxidized to an o-quinone and a hydroxy p-quinone, the chemical structures of which were confirmed by physical and chemical techniques. From a quantitative time course analysis of the production of these quinones, an antioxidant mechanism of carnosic acid is proposed, consisting of the oxidative coupling reaction with the peroxyl radical at the 12- or 14-position of carnosic acid and subsequent degradation reactions.

Abietanes↗
PubMed1990

Changes in food consumption patterns in Bahrain.

Changes in food consumption in Bahrain can be identified particularly in the second half of seventies with the wake of oil boom. The consumption of traditional foods such as fish and dates have declined, while that of processed foods, fat, eggs, meat, poultry and milk products have risen. The daily per capita intake of animal protein and fat have increased at the expense of carbohydrates. Some factors responsible for this change are increasing income and literacy, food price fluctuations, food subsidy policy, the influence of immigrant food habits, influence of mass media and the changing structure of households. The change in dietary intake has associated with change in health and nutritional problems in the country.

Bahrain↗
PubMedDate not supplied

[The bilateral interaction of the hypothalamus, amygdala and neocortex at different stages in conditioned reflex acquisition].

By averaged evoked potentials of the symmetric points of the cat's auditory cortex (Al), hypothalamus (Hl) and amygdala (Abl) in response to a sound was determined the character of the two-way interaction (Spearman coefficient of correlation) between the structures before and at different stages of instrumental food-procuring conditioning. Individual character of co-tuning of Al, Hl, and Abl as well as the emotional state connected with adaptation of an animal were found to be reflected in the correlation of evoked activity of the structures. Conditioning led to a formation of close interconnections between the structures eliminating individual peculiarities of correlation. Stabilization of the response was accompanied by a weakening of the interconnections between the cortex and the subcortical structures, internal symmetrical co-tuning of Al, Hl and Abl being unchanged.

Acoustic Stimulation↗
PubMed1998

Diet influences development of the pig (Sus scrofa) intestine during the first 6 hours after birth.

Structural and functional responses of the intestine to colostrum, milk replacer, oral electrolyte solution and food deprivation were examined during the first 6 h after birth in pigs. Total intestinal weight, surface area and mucosal mass were highest (P < 0.05) in pigs fed colostrum. The other diet groups did not differ, except that food-deprived pigs had lower surface area than the other groups. Feeding colostrum was associated with higher mucosal protein content (P < 0.05). Total intestinal brush border membrane protein content of pigs fed milk replacer, oral electrolyte solution and food-deprived pigs were 61, 44 and 56%, respectively, of those fed colostrum (P < 0.05). Pigs fed colostrum had higher total mucosal maltase activities than those that were food deprived, and total brush border membrane activities were higher than in those fed oral electrolyte solution. Total intestinal brush border membrane aminooligopeptidase activity was higher in pigs fed colostrum than in those given oral electrolyte solution or deprived of food, but total intestinal homogenate activities did not differ among groups. Diet influenced lactase activity only in the mid-region, and sucrase was not responsive to diet. Intestinal glucose transport capacity by intact intestinal tissues did not differ among diet groups. The ability of brush border membrane vesicles to actively accumulate glucose was lost when pigs were fed colostrum and milk replacer, but not when fed oral electrolyte solution or deprived of food. Our findings reveal how diet during the first 6 h after birth influences the structure and functional characteristics of the intestine. The responses vary between brush border membrane proteins and intestinal regions, and appear to differ from those described for older animals.

Animals↗