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Modifications of local cerebral glucose utilization during circadian food-anticipatory activity.

Food-anticipatory activity that animals express before a daily timed meal is considered as the behavioral output of a feeding-entrainable oscillator whose functional neuroanatomy is still unknown. In order to identify the possible brain areas involved in that timing mechanism, we investigated local cerebral metabolic rate for glucose during food-anticipatory activity produced either by a 4-h daily access to food starting 4 h after light onset or by a hypocaloric feeding provided at the same time. Local cerebral metabolic rate for glucose measured by the labeled 2-[(14)C]-deoxyglucose technique was quantified in 40 structures. In both groups of food-restricted rats, three brain regions (the nucleus of the solitary tract, the cerebellar cortex and the medial preoptic area) showed a decrease in local cerebral metabolic rate for glucose, compared with control ad libitum animals. In addition, only one structure, the paraventricular thalamic nucleus, was affected by temporal restricted feeding, and not by hypocaloric feeding, compared with ad libitum rats. By contrast, three brain regions, i.e. the intergeniculate leaflets, the paraventricular hypothalamic and the arcuate nuclei, showed specifically metabolic decreases during anticipation of hypocaloric feeding, and not during anticipation of temporal restricted feeding, compared with the ad libitum group. Expression of food-anticipatory activity appears to be regulated by an integrated neural circuit of brainstem and hypothalamic pathways, with hypocaloric feeding involving more extensive forebrain areas than temporal restricted feeding.

Animals↗

Cereal seed storage proteins: structures, properties and role in grain utilization.

Storage proteins account for about 50% of the total protein in mature cereal grains and have important impacts on their nutritional quality for humans and livestock and on their functional properties in food processing. Current knowledge of the structures and properties of the prolamin and globulin storage proteins of cereals and their mechanisms of synthesis, trafficking and deposition in the developing grain is briefly reviewed here. The role of the gluten proteins of wheat in determining the quality of the grain for breadmaking and how their amount and composition can be manipulated leading to changes in dough mixing properties is also discussed.

Consensus Sequence↗

Reduction of food intake and weight gain by the ob protein requires a specific secondary structure and is reversible.

BACKGROUND: Obesity, the condition of excessive accumulation of fat is a poorly understood disorder and is a risk factor for type II diabetes, hypertension, and hyperlipidaemia. Recently, a putative mouse obese gene was cloned and its product, termed ob protein, was shown to be involved in the regulation of body weight. MATERIALS AND METHODS: Bacterial and insect cells were used for expression of recombinant mouse ob protein. Amino-terminal sequence analysis and site-directed mutagenesis were used to identify and characterize the mature form of ob protein. Genetically obese mice and wild-type rats were used to determine the biological activity of ob protein. RESULTS: Mouse ob protein is synthesized as a precursor molecule, the mature form of which was found in mouse serum. Biochemical analysis identified the processing site in the ob precursor molecule and an intramolecular disulfide bond in the mature form that is necessary for activity. Reduction of food intake and weight gain after administration of ob protein to genetically obese mice and wild-type rats is reversible. DISCUSSION: This study demonstrates that ob protein is a secreted satiety factor which regulates body weight and reduces food intake even in animals with no genetic body weight abnormalities. The failure of ob protein to effect these parameters in db/db mice supports the hypothesis that these mice are deficient in a signaling molecule that normally responds to the ob protein.

Amino Acid Sequence↗

Whole foods and increased dietary fibre improve blood glucose control in diabetic children.

In prescribing a diabetic diet more attention has traditionally been paid to the amount of dietary carbohydrate than to its type or structure. We have compared the effect on blood glucose of substituting unrefined, whole foods for refined, processed foods in liberal carbohydrate diets (50-55% of dietary energy) eaten by 10 diabetic children in a randomised crossover study. All measurements were made at home. The unrefined diet used whole foods (including) dried beans) supplying 60 g/day of dietary fibre. The refined diet used processed foods supplying 20 g/day of dietary fibre. Diets were isocaloric for carbohydrate, fat, and protein. Glycaemic control was assessed by daily urine analysis for glucose, home blood glucose measurements, glycosylated haemoglobin, and by a 24-hour profile of blood and urinary glucose carried out at home after 6 weeks on each diet. Glycaemic control was significantly better on the unrefined diet. On profile days mean blood glucose levels on the unrefined and refined diets respectively were: preprandial: 5.5 and 8.4 mmol/l; postprandial 8.5 and 12.2 mmol/l. The mean 24-hour urinary glucose excretion on the unrefined diet was 9.3 g and on the refined diet was 38.0 g. Six months after the study the children were eating appreciably more dietary fibre than before (mean increase 13.6 g/day). Attention to food type and structure can improve blood glucose control in diabetic children and should provide an acceptable and more rational basis for dietary prescription than one based on carbohydrate quantity alone.

Adolescent↗

Pathway: a dynamic food-chain model to predict radionuclide ingestion after fallout deposition.

This manuscript describes the structure and basis for parameter values of a computerized food-chain transport model for radionuclides. The model, called "PATHWAY," estimates the time-integrated ingestion intake by humans of 20 radionuclides after a single deposition from the atmosphere to the landscape. The model solves a set of linear, coupled differential equations to estimate the inventories and concentrations of radionuclides in soil, vegetation, animal tissues and animal products as a function of time following deposition. Dynamic processes in the model include foliar interception, weathering and absorption; plant growth, uptake, harvest and senescence; soil resuspension, percolation, leaching and tillage; radioactive decay; and livestock ingestion, absorption and excretion. Human dietary data are included to permit calculation of time-dependent radionuclide ingestion rates, which are then numerically integrated. The model considers seasonal changes in the biomass of vegetation and animal diets, as well as specific plowing and crop-harvest dates; thus the integrated radionuclide intakes by humans are dependent on the seasonal timing of deposition. The agricultural data base represents the arid and semi-arid regions of the western United States. The foliar deposition parameters apply to regional fallout out to a few hundred miles from nuclear detonations at the Nevada Test Site. With modification, the model could be applied to chronic or other acute releases, providing the ground deposition in Bq m-2 could be estimated. The output of PATHWAY (Bq ingested per Bq m-2 deposited) may be multiplied by the deposition and a dose conversion factor (Gy Bq-1) to yield an organ-specific dose estimate. The model may be run deterministically to yield single estimates or stochastically ("Monte-Carlo" mode) to provide distributional output that reflects uncertainty in the output due to uncertainty in parameters. Tests of the predictive accuracy are briefly described and work published to date on validation trials is cited.

Animals↗

Genetic diversity of Listeria monocytogenes recovered from infected persons and pork, seafood and dairy products on retail sale in France during 2000 and 2001.

Growth of the food-borne human pathogen Listeria monocytogenes to large numbers in ready-to-eat food products greatly increases the risk of disease for susceptible consumers. A better knowledge of the population structure of L. monocytogenes present in retailed food could allow better prevention strategies to be developed. We present the analysis of 450 L. monocytogenes isolates, 179 responsible for sporadic human cases of listeriosis and 271 isolated from foods collected from retailers. All isolates were investigated by multiplex PCR (food isolates), allowing serovar predictions, or serotyped (human isolates), and DNA macrorestriction patterns were determined. Isolates from different sources were significantly differently distributed into PCR groups. PCR group IIa, corresponding to serovars 1/2a and 3a, was predominant in food isolates (58%; OR=3.19; P<1 x 10(-7)). A larger proportion of human isolates belonged to PCR group IVb, corresponding to serovars 4b, 4d and 4e (44%; OR=5.69; P<1 x 10(-7)). DNA macrorestriction pattern analysis of PCR group IIa isolates showed that isolates from pork products had a very low diversity (ID=0.905) whereas isolates from humans were more diverse (ID=0.976). Furthermore, 78% of the pork product isolates belonging to PCR group IIa exhibited only two AscI profiles, a(1) and a(2), which were very similar (94%). DNA array analysis of representative isolates showed that isolates with a(1) and a(2) profiles constitute a homogeneous population, whereas isolates exhibiting non a(1)-a(2) profiles are more diverse. Six of the isolates with a(1) and a(2) profiles were selected and investigated for their gene content using a DNA array. With respect to 295 strains present in our data collection, a specific pattern of the presence and absence of 15 genes was identified. Five are predicted to encode internalins and cell surface proteins, and eight of the genes were missing in this group. They code for cell surface proteins, transcriptional regulators, an acylase, a sugar phosphorylase and proteins of unknown functions. The ability of strains to multiply in different niches may be determined by the presence or absence of these genes.

Animals↗

Bioactive proteins and peptides from food sources. Applications of bioprocesses used in isolation and recovery.

There are many examples of biologically active food proteins, with physiological significance beyond the pure nutritional requirements that concern available nitrogen for normal growth and maintenance. Moreover, there are many physiologically active peptides, derived by protease activity from various food protein sources; however, relationships between structural properties and functional activities have not been completely elucidated. Many bioactive peptides have in common structural properties that include a relatively short peptide residue length (e.g. 2-9 amino acids), possessing hydrophobic amino acid residues in addition to proline, lysine or arginine groups. Bioactive peptides are also resistant to the action of digestion peptidases. Antihypertensive peptides, known as Angiotensin I converting enzyme (ACE) inhibitors have been derived from milk, corn and fish protein sources. Peptides with opioid activities are derived from wheat gluten or casein, following digestion with pepsin. Exorphins, or opioid peptides derived from food proteins such as wheat and milk (e.g. exogenous sources) have similar structure to endogenous opioid peptides, with a tyrosine residue located at the amino terminal or bioactive site. Immunomodulatory peptides derived from tryptic hydrolysates of rice and soybean proteins act to stimulate superoxide anions (reactive oxygen species-ROS), which triggers non-specific immune defense systems. Antioxidant properties that prevent peroxidation of essential fatty acids have also been shown for peptides derived from milk proteins. The addition of a Leu or Pro residue to the N-terminus of a His-His, dipeptide will enhance antioxidant activity and facilitate further synergy with non-peptide antioxidants (e.g. BHT). We also show herein, that the tryptic digests of casein yielding caseinophosphopeptides exhibits both hydrophilic and lipophilic antioxidant activity due to both metal ion sequestering and quenching of ROS. The separation and purification of bioactive peptides which will involve development of automated and continuous systems is an important field for Food chemists. Much effort has been given to develop selective column chromatography methods that can replace batch methods of salting out, or using solvent extraction to isolate and purify bioactive peptides. Advances here will enable recovery of bioactive peptides with minimal destruction thus enabling utilization by returning these active peptides to functional food or specific nutraceutical applications.

Adjuvants, Immunologic↗

A study of phagocytosis in the ameba Chaos chaos.

The process of phagocytosis was investigated by observing the interactions between the ameba Chaos chaos and its prey (Paramecium aurelia), by studying food cup formation in the living cell, and by studying the fine structure of the newly formed cup using electron microscopy of serial sections. The cytoplasm surrounding the food cup was found to contain structures not seen elsewhere in the ameba. The results are discussed in relation to the mechanisms which operate during food cup formation.

Eukaryota↗

Food restriction induces in vivo ventricular dysfunction in spontaneously hypertensive rats without impairment of in vitro myocardial contractility.

Cardiac structures, function, and myocardial contractility are affected by food restriction (FR). There are few experiments associating undernutrition with hypertension. The aim of the present study was to analyze the effects of FR on the cardiac response to hypertension in a genetic model of hypertension, the spontaneously hypertensive rat (SHR). Five-month-old SHR were fed a control or a calorie-restricted diet for 90 days. Global left ventricle (LV) systolic function was evaluated in vivo by transthoracic echocardiogram and myocardial contractility and diastolic function were assessed in vitro in an isovolumetrically beating isolated heart (Langendorff preparation). FR reduced LV systolic function (control (mean +/- SD): 58.9 +/- 8.2; FR: 50.8 +/- 4.8%, N = 14, P < 0.05). Myocardial contractility was preserved when assessed by the +dP/dt (control: 3493 +/- 379; FR: 3555 +/- 211 mmHg/s, P > 0.05), and developed pressure (in vitro) at diastolic pressure of zero (control: 152 +/- 16; FR: 149 +/- 15 mmHg, N = 9, P > 0.05) and 25 mmHg (control: 155 +/- 9; FR: 150 +/- 10 mmHg, N = 9, P > 0.05). FR also induced eccentric ventricular remodeling, and reduced myocardial elasticity (control: 10.9 +/- 1.6; FR: 9.2 +/- 0.9%, N = 9, P < 0.05) and LV compliance (control: 82.6 +/- 16.5; FR: 68.2 +/- 9.1%, N = 9, P < 0.05). We conclude that FR causes systolic ventricular dysfunction without in vitro change in myocardial contractility and diastolic dysfunction probably due to a reduction in myocardial elasticity.

Animals↗

A randomized controlled trial of a physician-directed treatment program for low-income patients with high blood cholesterol: the Southeast Cholesterol Project.

OBJECTIVE: To assess the effectiveness of a cholesterol-lowering intervention designed to facilitate the management of hypercholesterolemia by primary care clinicians. DESIGN: Randomized controlled trial, with randomization of clinician-patient groups. SETTING: Twenty-one community and rural health centers in North Carolina and Virginia. PARTICIPANTS: Primary care clinicians (n = 42, 71% physicians) and the patients they enrolled with high cholesterol (n = 372). Twenty-two clinicians were randomized to give the special intervention (184 patients) and 20 to give usual care (188 patients). Two thirds of participating patients were women, 40% were African American, and 11% were Native American. INTERVENTION: A 90-minute tutorial to train clinicians how to use a structured assessment and treatment program (Food for Heart Program) consisting of a brief dietary assessment and three 5- to 10-minute dietary counseling sessions given by the primary care clinician, referral to a local dietitian if the low-density lipoprotein cholesterol (LDL-C) remained elevated at 4-month follow-up, and a prompt for the clinician to consider lipid-lowering medication based on the LDL-C at 7-month follow-up. MAIN OUTCOME MEASURES: Changes in total and LDL cholesterol at 4-month follow-up and averaged over a 1-year follow-up period (4-, 7-, and 12-month follow-up). RESULTS: At 4-month follow-up, total cholesterol decreased 0.33 mmol/L (12.6 mg/dL) in the intervention group and 0.21 mmol/L (8.3 mg/dL) in the control group: the difference was 0.11 mmol/L (4.2 mg/dL) (90% confidence interval [CI], -0.02 to 0.24 mmol/L [-0.7 to 9.1 mg/dL]). The average reduction during the 1-year follow-up period was 0.09 mmol/L (3.6 mg/dL) greater in the intervention group (90% CI, -0.01 to 0.19 mmol/L [-0.3 to 7.5 mg/dL]). Eight percent of intervention patients were taking lipid-lowering medication at follow-up visits compared with 15% of control patients. In a subgroup analysis restricted to the 89% of returnees who were not taking lipid-lowering medication, the reduction in total cholesterol at 4-month follow-up was 0.14 mmol/L (5.5 mg/dL) greater in the intervention group (95% CI, 0.01 to 0.28 mmol/L [0.3 to 10.7 mg/dL]); averaged over 1 year, it was 0.14 mmol/L (5.3 mg/dL) greater (95% CI, 0.03 to 0.24 mmol/L [1.2 to 9.4 mg/dL]). Changes in LDL-C were similar. CONCLUSIONS: Total cholesterol and LDL-C decreased more in the intervention group than in the control group. Overall, the difference in lipid reduction between groups was modest and of borderline statistical significance; among participants who did not take lipid-lowering medication during follow-up, the difference in lipid reduction between groups was larger. We conclude that primary care clinicians can be trained to give a cholesterol-lowering intervention to low-income patients that results in modest, short-term reductions in total cholesterol and LDL-C.

Cholesterol, LDL↗

Maillard glycation of beta-lactoglobulin induces conformation changes.

Glycation by the Maillard reaction is an ubiquitous reaction of condensation of a reducing sugar with amino groups of proteins, which products could improve the functional and/or biological properties for food and non-food uses. It can induce structural modifications in proteins, modifying their properties. The aim of this work was to investigate the association behavior and the conformational changes of beta-lactoglobulin (BLG) after its glycation by the Maillard reaction with several alimentary sugars (arabinose, galactose, glucose, lactose, rhamnose and ribose). Protein samples were heated in the presence or in the absence (heated control) of different sugars during 3 days at 60 degrees C. Glycation induced oligomerization of BLG monomers. Depending on the reactivity of the sugar, the population of produced oligomers showed smaller or greater heterogeneity in molecular masses. Analysis of modified BLG by circular dichroism and by its susceptibility to pepsinolysis showed that the conditions of heating used did not significantly alter the conformation of BLG. Heating of BLG in presence of sugars induced only minor structural modification, when using the less reactive sugars such as lactose and rhamnose. It was, however, at the origin of major three-dimensional destructuring in the case of the more reactive sugars such as arabinose and ribose. Pepsinolysis of glycated BLG did not affect about 62 and 35% of the protein molecules modified with lactose or rhamnose, and arabinose or ribose, respectively. The increase of susceptibility of glycated BLG to pepsinolysis could be related to the alteration of the conformation of the protein when glycation was performed with highly reactive sugars, as observed by circular dichroism and calorimetry analysis.

Carbohydrates↗

The toxicity of behenyl alcohol. II. Reproduction studies in rats and rabbits.

Behenyl alcohol is a saturated 22-carbon, long-chain aliphatic alcohol, which has potential for use in foods as an oil-structuring and -solidifying agent in fats. Previously completed studies with behenyl alcohol indicated an absence of mutagenic or genotoxic potential. In addition, subchronic toxicity studies in rats and dogs reported no adverse effects following gross and histopathological examinations. Compound-related effects were limited to the observation of pale feces in dogs treated with high doses of behenyl alcohol, and were attributable to unabsorbed behenyl alcohol. The reproductive effects of behenyl alcohol were investigated in a fertility and reproduction study, and an embryonic development study in rats and rabbits, respectively. No evidence of maternal or fetal toxicity was observed in either study. Behenyl alcohol demonstrated no effects on the fertility or reproduction of rats dosed up to 1000 mg/kg body weight. Similarly, behenyl alcohol had no reproductive effects on rabbits treated with doses up to 2000 mg/kg body weight. The observation of pale feces was the only compound-related effect reported, limited to rabbits treated with 2000 mg behenyl alcohol/kg body weight. Based on these findings, there is no evidence to suggest that behenyl alcohol is teratogenic or embryotoxic.

Abnormalities, Drug-Induced↗

Acute pesticide morbidity and mortality: California.

The California Pesticide Illness Surveillance Program collects, investigates, abstracts, and records reports received from physicians. A minority of the reports are received through the county health officers who are notified by physicians under a state requirement for reporting pesticide-caused conditions. Most of the cases are identified by review of workers' compensation records. All the cases identified are investigated by the agricultural commissioners of the counties where exposure occurred. The investigation reports are reviewed and abstracted by staff of the Worker Health and Safety Branch of the California Department of Pesticide Regulation, California Environmental Protection Agency (Cal/EPA). The crucial determination is assessment of the degree of relationship between the exposure and subsequent disease: definite, probable, possible, unlikely, or unrelated. In most years, the number of cases investigated has been between 2,500 and 3,000. Excluding antimicrobials, the number of cases found after investigation to have a definite, probable, or possible relationship with pesticide exposure has ranged from 970 (in 1989) to 1,372 (in 1988). Cases involving antimicrobials rarely were reported prior to 1987. In that year, surveillance staff began reviewing workers' compensation records personally, with the specific goal of identifying antimicrobial cases. Since then, antimicrobials have been found to account for 746-813 cases annually, primarily involving splashes and squirts to the eye and inhalation of fumes or vapors. Numbers of case reports from agricultural situations have varied irregularly, driven by small numbers of episodes concerning multiple individuals. Variability in numbers of cases involving the skin has depended almost entirely on variation in numbers of field worker dermatitis. The most common situation for field worker dermatitis has been summer work in table grapes grown in the southern San Joaquin valley. In the two years since reentry intervals for the acaricide propargite were lengthened, there have been no more major clusters of field worker dermatitis. Although the cases collected by the surveillance program are predominantly occupational, because of dependence on workers' compensation for case identification, most recorded deaths are nonoccupational. Nonoccupational fatalities include suicides, mistaken ingestion of pesticides (especially if stored in food containers), and entry into structures being fumigated. Occupational deaths are less common and more varied. The circumstances of each reported occupational death are summarized above.

California↗

[Body weight regulation through the central nervous system. The development of a pathogenetically based adiposity therapy].

The last decade witnessed a dramatic increase in knowledge concerning regulation of body weight and obesity. According to recent concepts constancy of body weight is a side product of regulatory events which ensure constant glucose fluxes to the brain. Within these control systems glucocorticoids and melanocortins play a fundamental role at several sites. The melanocortin neurons in the arcuate nucleus of the hypothalamus are important mediators of the feedback effects of leptin and insulin. Glucocorticoid and mineralocorticoid receptors in hippocampal neurons are crucial, as they define the balance between glucose allocation processes and food intake. Thereby, the hippocampal structures determine the setpoint for body weight regulation. A modulation of these brain structures by intranasal administration of melanocortin and inhisulin has been shown to reduce body weight and body fat mass in humans. So the manipulation of weight-regulating centers in the brain opens a novel approach to a pathogenetically based treatment of obesity.

Administration, Intranasal↗

Regeneration of tactile lamellar corpuscles of the rat after postnatal freeze injury.

Tactile lamellar corpuscles were studied after freeze injury of rat toe pads under normal conditions and following permanent denervation in 1- to 65-day-old animals. In the innervated skin, digital corpuscles redifferentiated in all age groups examined during development and maturation. Characteristic of the reinnervated skin was a great diversity in the shape and size of newly formed corpuscles. Small corpuscles with only 1-3 lamellae around their terminals and well-developed corpuscles of about normal size with up to 15 lamellae were sometimes found within the same sample of skin. The regenerated corpuscles were reduced in number; they reappeared in only 50% of dermal papillae in the toe pads after freeze injury in 7-week-old rats, compared with approximately 100% of dermal papillae that contained lamellar corpuscles in normal toe-pad skin. In denervated toes, occasional corpuscular lamellar structures appeared first after freeze injury applied to 34-day-old rats. In the toe pads denervated and injured by freezing in 42- and 49-day-old rats, lamellar structures redifferentiated in about 10% of the papillae, and in 23.5% after freeze injury applied to 2-month-old rats. Unsatisfactory preservation of basal laminae at the former sites of the corpuscles and in the acellular peripheral nerve stumps, and/or insufficient migration of Schwann cells, may be responsible for the absence or abortive regeneration of lamellar structures in denervated skin of food pads after freeze injury in young rats.

Animals↗

Striatal influence on ingestive behaviour in the cat.

In freely moving cats with chronically implanted electrodes an analysis was made of the effects on feeding behaviour of low-frequency long-duration stimulation of the caudate nucleus, the substantia nigra and the globus pallidus. In all 3 structures a significant reduction of food intake was observed and in the pallidus this reached the point of a complete block of feeding. The effects were always limited to the period of stimulation. At the end of stimulation the animals recovered and took in food quantities equal to those of controls. The results are interpreted on the basis of reciprocal connections between the basal ganglia and the hypothalamus; the role of the striatum on the selection of certain movements and its possible involvement in behaviour is also discussed.

Animals↗

Toxicology then and now.

A review of the history of the evolution of the science of toxicology from the original concepts of Paracelsus through the early development of analytical chemistry and its contributions to the detection of toxic substances in foods and drugs as these have led to modern regulatory rules for public protection is presented. The legal actions taken to protect against adulteration of food prior to the early steps by the U.S. Department of Agriculture that concluded with the passage of the 1906 Food and Drug Act are systematically documented. The history is reviewed of the Food and Drug Administration's role in the use of animal toxicity studies to develop reasonable criteria for safety of foods and drugs for man. Modern concepts of molecular distribution, metabolism, and excretion of substances in the animal body are discussed as these impinge on the so-called "protection index." The legal and often litigious controversies over the claimed carcinogenicity of chemical substances is documented with comments on the Delaney dilemma and the role of in vitro tests in toxicology. The review concludes with a discussion of the hazards of use of stochastic mathematical models to assess carcinogenicity and suggests that the criteria employed in the report of the Scientific Committee of the Food Safety Council are properly structured to give a contemporary evaluation of all the currently available data. References give documentation of events over the past 200 years that explain the present state of toxicology as a discipline.

Europe↗