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PubMed2003

Inhibitory effect of dibenzoylmethane on mutagenicity of food-derived heterocyclic amine mutagens.

Dibenzoylmethane (DBM), a structural analogue of curcumin (a bioactive phytochemical present in a widely used spice turmeric) was screened for its inhibitory effect against seven cooked food mutagens (heterocyclic amines): 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 3-amino-1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), in both TA98 and TA100 strains of Salmonella typhimurium using Ames Salmonella/reversion assay in the presence of Aroclor1254-induced rat liver S9 homogenate. DBM has been reported to antagonize the mutagenicity of several chemical carcinogens in vitro and has recently been shown to be even more effective than curcumin in suppressing the 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors in rats. But there are no reports regarding its antimutagenic properties against cooked food mutagens. Results of the present investigations clearly indicate that dibenzoylmethane is a very potent antimutagenic agent, that could effectively inhibit mutagenicity induced by all the tested cooked food mutagens in both the frame shift (TA98) as well as the base pair mutation sensitive (TA100) strains of S. typhimurium. These highly potent inhibitory effects of dibenzoylmethane against heterocyclic amines observed in our preliminary investigations strongly warrant further studies of its efficacy as a cancer chemopreventive agent.

Amines↗

PubMed1990

[Immunochemical analysis of structural changes in ovalbumin caused by heat: possible application to the quick control of food sterilization].

Bacteriological methods, to determine proper hygiene control for food for human consumption suffers from inordinate delay (1-4 days) in the methodology before an accurate answer can be given regarding the food safety. In contrast by immunochemistry results can be obtained in 15 to 30 minutes. As it is known that during heating processing protein structure is modified, a careful identification of epitopic changes by monoclonal antibodies could be of help. It was found that after heat treatment, ovalbumin structure modified depending upon the temperature of heating. Monoclonal antibodies were raised against either native or heat denatured ovalbumin. Such monoclonal antibodies bound to plastic can be used for the immunocapture of ovalbumin in solution which is then revealed by polyclonal antibodies. With five different monoclonal antibodies it was possible to identify either native ovalbumin or heat denatured ovalbumin between 50 degrees C and 65 degrees C or heat denatured ovalbumin between 85 degrees C and 100 degrees C. Work is in progress to recognize epitopes specific of temperature and time of heating.

Albumins↗

PubMed1992

Immunoassays of amphetamines: immunogen structure vs antibody specificity.

Various immunoassays have been developed for the detection of amphetamines. These have varying degrees of cross-reactivity to other drug and food components. Information on the immunogen structures used, and the specificities of the antibodies obtained, have allowed formulation of a "structure-specificity" pattern delineated on the basis of immunochemistry and stereochemistry. The 'structure-specificity' relationship should be useful to future developments of these immunoassays. Specifically, immunoassays intended to detect either amphetamine or methamphetamine with minimal cross-reaction, should employ immunogens with amphetamine (or methamphetamine) derivatized via the para position of the phenyl ring. Such assays should show minimal cross-reaction with other secondary (or tertiary) amines but should strongly cross-react with phenyl ring substituted analogs. On the other hand, assays intended for detection of both amphetamine and methamphetamine should employ amphetamine (rather than methamphetamine) derivatized via its amino group as an immunogen. Such assays should show minimal cross-reaction with other tertiary amines and phenyl-substituted amphetamine/methamphetamine.

Amphetamines↗

PubMed1997

Parallel medullary gustatospinal pathways in a catfish: possible neural substrates for taste-mediated food search.

Taste and tactile fibers in the facial nerve of catfish innervate extraoral taste buds and terminate somatotopically in the facial lobe (FL)-a medullary structure crucial for gustatory-mediated food search. The present study was performed to determine the neural linkages between the gustatory input and the spinal motor output. Spinal injections of horseradish peroxidase (HRP) label spinopetal cells in the octaval nuclei, the nucleus of the medial longitudinal fasciculus, and reticulospinal neurons (Rsps) in the brainstem medial reticular formation (RF), including the Mauthner cell. A somatotopically organized, direct faciospinal system originating from superficial cells scattered in the lateral lobule of the facial lobe (ll) is also labeled. The brainstem reticulospinal cells are segmentally organized into 14 clusters within eight segments of the reticular formation and includes one cluster (RS5) directly ventral to the FL. Injections of HRP or fluorescent tracers into the medial lobule of the FL label a facioreticular projection terminating around the Rsps of RS5. DiI injections into this area of the RF retrogradely label deeply situated bipolar neurons, especially in the medial and intermediate lobules of the FL. Electrophysiological recordings in and around RS5 show units with large receptive fields and with responses to chemical and tactile stimulation. The FL projects to the spinal cord via two pathways: (1) a topographically organized direct faciospinal pathway, and (2) an indirect facioreticulospinal pathway in which reticular neurons process and integrate gustatory information before influencing spinal circuitry for motor control during food search.

Animals↗

PubMed2000

[Effect of pretreatment on the measurement of folate in foods].

In order to measure the content of folate in foods accurately, to hydrolyze and extract folate in foods with suitable pretreatment is necessary because folate in foods is always in polyglutamate structure. The pretreatment of samples including hydrolysis with phosphate buffer(0.05 mol/L, pH 6.8) once or twice, with chick pancreatin, protease and/or amylase, and a combining of trienzyme methods was compared and discussed. A microbiological method with lactobacillus casei was used. A high result of folate in foods could be obtained when extracting folate enriched samples or vegetables with phosphate buffer once or twice respectively, or hydrolyzing "extracted oral liquids" with chick pancreatin, or when extracting samples rich in protein and/or starch with trienzyme. The RSD of interassay and intrassay were 6.5%-9.9% and 3.5%-14.1% respectively, and the recovery rate was 86.8%-106.8%.

Animals↗

PubMed1986

Chemistry of mutagens and carcinogens in broiled food.

From a chemical point of view, the following subjects are important areas in studies on mutagens and carcinogens in broiled foods. In addition to heterocyclic amines which need microsomal activation, the structural elucidation of more labile direct-acting mutagens is necessary. It is known that there are still various unknown minor mutagens in broiled foods. Although the structural characterization of such compounds is more difficult, it is important since they might be hazardous in spite of their low mutagenicity. A more feasible and easier method for quantitative analysis of mutagens, in addition to HPLC and GC/MS methods presently employed, must be developed. The mechanism of formation of mutagens by broiling of food should be studied. An effective chemical method to prevent formation of mutagens or to destroy them, once formed, should be developed.

Carcinogens↗

PubMed2003

Empowered women, social networks and the contribution of qualitative research: broadening our understanding of underlying causes for food and nutrition insecurity.

OBJECTIVE: To investigate underlying causes for food and nutrition insecurity in black South African households and to gain understanding of the factors contributing to better nutrition security, with emphasis on household organisation, gender and intra-household dynamics and social networks. DESIGN, SETTING AND SUBJECTS: Within a larger cross-sectional survey that investigated the impact of urbanisation on the health of black South Africans, 166 people, mostly women, were interviewed on household food security. Methods used were structured face-to-face interviews, in-depth interviews, observation, interviews with key informants and a sociodemographic questionnaire. Information was collected from 1998 to 2000 in 15 rural and urban areas of the North West Province, South Africa. RESULTS: Three-quarters of households in this sample are chronically food-insecure. Families are disrupted, due to migrant work, poverty and increasing societal violence, and half of households are female-headed. Certain categories of female-headed households and households based on partnership relationships, despite more limited resources, achieve a better or an equal economic status and better nutrition security than those households led by men, with the latter often being considered an economic liability. The reliance on and fostering of social ties and networks appear to be of central significance. CONCLUSION: Gender and intra-household relations, as well as social networks and income from informal sector activities, are often not uncovered by conventional statistical methods. Qualitative research can reveal the unexpected and furthermore empowers people, as their voices are heard.

Adult↗

PubMed2003

Comparison of enterococcal populations in animals, humans, and the environment--a European study.

The objectives of the present study were to generate knowledge of enterococcal populations in the food chain, by studying the population structure (in measures of abundance and diversity) among enterococci in different geographical regions and in different parts of the food chain, as well as the similarities between different enterococcal populations. Altogether, 2868 samples were collected from humans (healthy and hospitalised individuals and clinical isolates), animals (slaughterhouse carcasses and farm animals), and the environment (pig farms, sewage, and surface water) in four European countries-Sweden, Denmark, UK, and Spain. The samples were characterised with regard to presence and numbers of enterococci, and eight (for faecal samples) or 24 (for environmental samples) isolates per sample were phenotyped and preliminarily identified with the PhP-RF system. In total, more than 20,000 isolates were typed. A majority of the samples (77%) showed the presence of presumed enterococci. The diversities of enterococci in environmental samples were generally high, and also faecal samples normally showed presence of more than one enterococcal strain. The most common species found were Enterococcus faecium (33%), E. faecalis (29%), and E. hirae (24%), but different enterococcal populations differed in their species distribution. Clinical isolates, hospitalised patients, and hospital sewage in Sweden showed a clear dominance of E. faecalis (80%, 57%, and 54%, respectively) whereas healthy individuals and urban sewage contained less E. faecalis (39% and 40%, respectively). The species distribution among isolates from slaughterhouses varied between animal species and also between countries, but E. faecalis seemed to be mainly associated with broiler, and E. hirae with cattle and pigs. The results from the study have indicated a simplified method to study the diversity of bacterial populations. Instead of collecting many samples and analysing one or a few isolates per sample, it is possible to collect fewer samples and analyse several isolates per sample. Both approaches yielded similar information on the diversity of the populations. Another useful information was that since samples from hospital sewage, urban sewage, and manure contained enterococcal populations that reflected those in faecal samples of hospitalised patients, healthy humans, and animals, respectively, such samples may be used as pooled faecal samples and may replace cumbersome samplings from many individuals.

Animals↗

PubMed2004

[Junk food consumption and child nutrition. Nutritional anthropological analysis].

The increasing consumption of junk food and snacks in Chile in recent years and its association with marketing strategies and prevalent diseases, is reviewed. In the context of world economy, junk food is a global phenomenon. The availability of junk food and snacks at low prices and marketing has triggered an evolution of consumption of foods that require neither the structure nor the preparation of a formal meal. Many studies have suggested that the increase in snack consumption is associated with an increase in obesity, tooth decay and other chronic diseases among children and adolescents. The hypothesis suggests a link between the pattern of snack consumption and an increase increase in the energy density of food consumed, a decrease in satiety, passive over consumption, and an increase in obesity. Between 1977 and 1996, the contribution: of snacks to daily energy intake among children between 2 and 5 years increased by 30% in the United States. In each age group in Chile the frequency of non-transmissible chronic diseases is increasing due primarily to a westernized diet that is high in fat, cholesterol, sodium, and sugar and a sedentary lifestyle. Education about junk food consumption and healthy eating habits in the family, starling since childbirth and public policies about healthy lifestyles should be strengthened.

Anthropology↗

PubMed2004

Oxyntomodulin and glucagon-like peptide-1 differentially regulate murine food intake and energy expenditure.

BACKGROUND & AIMS: Gut-derived peptides including ghrelin, cholecystokinin (CCK), peptide YY (PYY), glucagon-like peptide (GLP-1), and GLP-2 exert overlapping actions on energy homeostasis through defined G-protein-coupled receptors (GPCRs). The proglucagon-derived peptide (PGDP) oxyntomodulin (OXM) is cosecreted with GLP-1 and inhibits feeding in rodents and humans; however, a distinct receptor for OXM has not been identified. METHODS: We examined the mechanisms mediating oxyntomodulin action using stable cell lines expressing specific PGDP receptors in vitro and both wild-type and knockout mice in vivo. RESULTS: OXM activates signaling pathways in cells through glucagon or GLP-1 receptors (GLP-1R) but transiently inhibits food intake in vivo exclusively through the GLP-1R. Both OXM and the GLP-1R agonist exendin-4 (Ex-4) activated neuronal c-fos expression in the paraventricular nucleus of the hypothalamus, the area postrema, and the nucleus of the solitary tract following intraperitoneal (i.p.) injection. However, OXM transiently inhibited food intake in wild-type mice following intracerebroventricular (i.c.v.) but not i.p. administration, whereas Ex-4 produced a more potent and sustained inhibition of food intake following both i.c.v. and i.p. administration. The anorectic effects of OXM were preserved in Gcgr(-/-) mice but abolished in GLP-1R(-/-) mice. Although central Ex-4 and OXM inhibited feeding via a GLP-1R-dependent mechanism, Ex-4 but not OXM reduced VO2 and respiratory quotient in wild-type mice. CONCLUSIONS: These findings demonstrate that structurally distinct PGDPs differentially regulate food intake and energy expenditure by interacting with a GLP-1R-dependent pathway. Hence ligand-specific activation of a common GLP-1R increases the complexity of gut-central nervous system pathways regulating energy homeostasis and metabolic expenditure.

Amino Acid Sequence↗

PubMed2007

Nectar and pollen feeding by insect herbivores and implications for multitrophic interactions.

Among herbivorous insects with a complete metamorphosis the larval and adult stages usually differ considerably in their nutritional requirements and food ecology. Often, feeding on plant structural tissue is restricted to the larval stage, whereas the adult stage feeds primarily or exclusively on plant-provided food supplements such as nectar and pollen. Research on herbivore nutritional ecology has largely been divided along these lines. Most studies focus on actual herbivory by larval stages, while nectar and pollen feeding by adult herbivores has been addressed mainly in the light of plant-pollinator interactions. Only recently have we started to realize that the two phenomena are closely interlinked and that nectar and pollen feeding by adult herbivores can have a strong impact on plant-herbivore interactions. Here we address this largely ignored aspect of multitrophic level interactions and discuss its wide-ranging implications.

Animals↗

PubMed1991

In vivo structure activity study supports the existence of heterogeneous neuropeptide Y receptors.

The purpose of the present study was to examine relationships between structure and activity of the peptide for stimulating food intake and decreasing body temperature in rats. Various NPY fragments and structural analogs were administered intracerebroventricularly in several doses (2.5-160 micrograms) and their effects on feeding and body temperature evaluated and compared. Globally, results indicate that the C-terminal portion of the peptide is responsible for both central effects of NPY. However, the distributions of potencies of the various fragments and analogs for increasing food intake and decreasing body temperature were clearly different. The most salient difference was that deletion of the N-terminal residue Tyr1 of NPY resulted in a five-fold loss in the potency for decreasing rectal temperature, whereas NPY2-36 was relatively more potent than the native peptide to increase food intake in animals. These results suggest that the purported receptors mediating the effect of NPY on food intake are different than those responsible for the influence of the peptide on body temperature. The results of the present in vivo work are discussed in relation to those obtained in previous in vitro studies.

Animals↗

PubMed2000

Intracerebroventricular injection of murine leptin enhances the postprandial metabolic rate in the rat.

Energy balance is achieved by means of a concomitant control of both food intake and energy expenditure. Leptin, synthesized in the adipose tissue, acts on brain structures and lowers body weight by inhibiting food intake and in parallel by enhancing energy expenditure i.e. metabolism or one of its components. Recording distinctly these components allowed us to assess the effect of an acute intracerebroventricular injection of leptin on both feeding pattern and background metabolism (i.e. energy expenditure free from the part of locomotor activity), respiratory quotient, feeding-related metabolism and locomotor activity-related metabolism. Leptin injection to Sprague-Dawley male rats induced an inhibition of feeding that began 90 min after the treatment and lasted 1 h before to return to the control feeding pattern level. Considering this late behavioral effect, it appeared that leptin may act during the postprandial period so that we recorded the different metabolic parameters following a 3 g calibrated meal itself preceded by leptin vs. artificial cerebrospinal fluid injection. Postprandial respiratory quotient was rapidly lowered in leptin-treated animals and subsequent background metabolism increased for 6 h. Thus it appeared that leptin increased the duration of the postprandial metabolic rate via the recruitment of endogenous fat stores. Enhancement in the thermic effect of food may be the reason for feeding behavior inhibition to be delayed.

Animals↗

PubMed1983

Anorexia after adrenalectomy in gold thioglucose-treated obese mice.

The effects of adrenalectomy on food intake, weight gain, plasma glucose, and corticosterone levels were investigated in normal untreated controls and gold thioglucose-(GTG) treated hyperphagic obese mice. Adrenalectomy of normal untreated mice was followed by a transient reduction in food intake and body weight with a return, after approximately 7 days, to levels which paralleled those of untreated sham-operated mice. Plasma corticosterone levels were significantly depressed in all untreated adrenalectomized mice. Plasma glucose levels were not affected by adrenalectomy. In sharp contrast to the response of untreated adrenalectomized mice, adrenalectomy of GTG-treated hyperphagic obese mice was followed by a sudden and persistent drop in food intake (anorexia) and body weight. These mice were unable to maintain their body weight. Despite this condition, the mice did not appear to be physically debilitated until a short time (6-12 h) before their death which was preceded by a period of severe hypoglycemia. These findings indicate that the hyperphagia and weight gain of GTG-treated obese mice is dependent on adrenal hormones. The anorexia after adrenalectomy of GTG-treated hyperphagic obese mice may be the result of a direct dependence of central or peripheral structures involved in the regulation of food intake on adrenal hormones. Alternatively, these structures may be affected by the action of metabolites or hormones which arise as a consequence of adrenal insufficiency.

Adrenalectomy↗

PubMed1988

Synthesis and mutagenic activity of nitro-imidazoarenes. A study on the mechanism of the genotoxicity of heterocyclic arylamines and nitroarenes.

A series of nitro-imidazoarenes (nitro-IAs) were synthesized from the corresponding amino-imidazoarenes (amino-IAs). These two classes of compounds are structurally related to the potent food mutagen and carcinogen, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). The mutagenic activities of the nitro-IAs were assayed in the Salmonella typhimurium frameshift tester strains TA98, TA98/1,8-DNP6 and TA98NR without use of extracellular metabolization. Nitro-IQ, the nitro counterpart of IQ, was two times more mutagenic than IQ. In general, the mutagenic activities of the nitro-IAs varied over 50,000-fold. The relationships between the chemical structures and mutagenic activities are identical with those previously reported for the corresponding amino-IAs: the methyl group on the imidazole ring and the quinoline-nitrogen were found to be required for potent mutagenic activity. The reductive activation of the nitro-IAs is not carried out primarily by the 'classical' nitroreductase of Salmonella which is defective in TA98NR. The O-acetyltransferase defective in TA98/1,8-DNP6 is required for the efficient production of the ultimate mutagens of the nitro-IAs. The interchangeability of the structure-activity relationships of the nitro-IAs and amino-IAs reflects a basic similarity of the mechanisms of the mutagenicity of the two classes of compounds. It is likely that N-hydroxy compounds are proximate metabolites common to the nitro-IAs and amino-IAs; they are further activated by an acetyl-CoA-dependent O-acetyltransferase of Salmonella. It is very likely a property of the ultimate mutagen, possibly a nitrenium ion, which governs the mutagenic potency of the different nitro- and amino-IAs and thus determines the structure-activity relationships.

4-Nitroquinoline-1-oxide↗

PubMed2001

Swim-trained rats have greater bone mass, density, strength, and dynamics.

Weight-bearing exercise is traditionally recommended for improving bone health in postmenopausal women. Effects of swim exercise were studied as an alternative to weight-bearing exercise in ovariectomized rats. Rats in a swim group (Sw, n = 8) swam for 12 wk, 5 days/wk for 60 min per session. A control group (Con, n = 9) engaged in no structured exercise. Femurs were analyzed for bone mineral density and for bone mineral content by dual energy X-ray absorptiometry, biomechanical properties by three-point bending (Instron), and bone structure and formation by histomorphometry. Food intake did not differ among groups. Final body weights were significantly lower in Sw compared with Con (P < 0.05). Swimmers had significantly greater femoral shaft bone mineral density and content (P < 0.05) compared with Con. Femurs of the Sw group had greater mechanical properties (P < 0.05) compared with Con. Histomorphometric data were significantly better in the Sw group compared with Con after the 12-wk intervention (P < 0.05). In conclusion, data from this study demonstrate some beneficial effects of swim exercise on bone structure, turnover, and strength.

Absorptiometry, Photon↗

PubMed1995

Nutritional status and food security: winter nutrition monitoring in Sarajevo 1993-1994.

OBJECTIVE: To monitor nutritional status and food security throughout the winter of 1993-1994 in order to provide early warning of any deterioration, identify the nutritionally vulnerable and so enable humanitarian agencies to respond appropriately. DESIGN: Four different household groups were prospectively followed: residents, refugees in collective centres, refugees in private accommodation and elderly living alone (either residents or refugees). Four local communities were purposively selected and two collective centres were randomly selected. Households were randomly selected within each community and collective centre. An additional sample of all elderly inhabitants of the old people's home were nutritionally assessed only. SETTING: Monitoring was implemented in the besieged city of Sarajevo. SUBJECTS: 143 households with 90 children (< 18 years), 230 adults (18-59 years), and 94 elderly (60 + years) members, and 40 elderly inhabitants of the old people's home were monitored. INTERVENTIONS: Every month from December 1993 to March 1994, information on household food security was collected through structured questionnaires. All subjects were weighed and their heights measured. Weight for age Z scores in children (six months to 12 years) and body mass index (BMI) in adults and the elderly were calculated. RESULTS: While the nutritional status of adults and children consistently remained normal, high levels of undernutrition were detected among the elderly ranging from 16% to 21% (BMI < 18.5). Between December 1993 and February 1994, adults lost an average of 260 grams in weight (paired t test p = 0.005). Indicators of household food security (food stocks per person, market food prices and access to food aid) showed negative trends during the same time period. CONCLUSIONS: Whilst there was no nutritional disaster in Sarajevo over the winter 1993-1994, there were signs that capacity to cope was weakening in some groups. The elderly were identified as the most nutritionally vulnerable due to sickness, cold, stress and problems related to food preparation. The most food insecure group were refugees in collective centres who were highly dependent on food aid, were less likely to have relatives outside Sarajevo to support them, had fewer possessions to sell and were least likely to have gardens.

Adolescent↗

PubMedDate not supplied

Neural sites and pathways regulating food intake in birds: a comparative analysis to mammalian systems.

The paper reviews hypotheses explaining the regulation of food intake in mammals that have addressed specific anatomical structures in the brain. An hypothesis, poikilostasis, is introduced to describe multiple, homeostatic states whereby the regulation of metabolism and feeding occur in birds. Examples are given for both wild and domestic avian species, illustrating dynamic shifts in homeostasis responsible for the changes in body weights that are seen during the course of an annual cycle or by a particular strain of bird. The following neural structures are reviewed as each has been shown to affect food intake in birds or in mammals: ventromedial hypothalamic nucleus (n.), lateral hypothalamic area, paraventricular hypothalamic n., n. tractus solitarius and area postrema, amygdala, parabrachial n., arcuate n. and bed n. of the stria terminalis. Two neural pathways are described which have been proposed to regulate feeding. The trigeminal sensorimotor pathway is the most complete neural pathway characterized for this behavior and encompasses the mechanics of pecking, grasping and mandibulating food particles from the tip of the bill to the back of the buccal cavity. A second pathway, the visceral forebrain system (VFS), affects feeding by regulating metabolism and the balance of the autonomic nervous system. Wild, migratory birds are shown to exhibit marked changes in body weight which are hypothesized to occur due to shifts in balance between the sympathetic and parasympathetic nervous systems. Domestic avian species, selected for a rapid growth rate, are shown to display a dominance of the parasympathetic nervous system. The VFS is the neural system proposed to effect poikilostasis by altering the steady state of the autonomic nervous system in aves and perhaps is applicable to other classes of vertebrates as well.

Animals↗