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At least 1,153 records · Page 64Linked to original sources
PubMed2004

Effect of sucrose on the properties of caffeine adsorption layers at the air/solution interface.

Sweet and bitter tastes are known to be mediated by G-protein-coupled receptors. The relationship between the chemical structure of gustable molecules and their molecular organization in saliva (aqueous solution) near the surface of the tongue provides a useful tool for elucidating the mechanism of chemoreception. The interactions between stimulus and membrane receptors occur in an anisotropic system. They might be influenced by the molecular packing of gustable molecules within an aqueous solvent (saliva) close to the receptor protein. To investigate the molecular organization of a sweet molecule (sucrose), a bitter molecule (caffeine), and their mixture in an aqueous phase near a "wall", a hydrophobic phase, we modeled this using an air/liquid interface as an anisotropic system. The experimental (tensiometry and ellipsometry) data unambiguously show that caffeine molecules form an adsorption layer, whereas sucrose induces a desorption layer at the air/water interface. The adsorption of caffeine molecules at the air/water interface gradually increases with the volume concentration and is delayed when sucrose is added to the solution. Spectroscopic ellipsometry data show that caffeine in the adsorption layer has optical properties practically identical to those of the molecule in solution. The results are interpreted in terms of molecular association of caffeine with itself at the interface with and without sucrose in the subphase, using the theory of ideal gases.

Adsorption↗
PubMed1995

A taste of copper.

New structures of copper containing proteins with cupredoxin-like folds confirm earlier predictions, and reveal electron-transfer routes in cytochrome oxidase, while a new fold for amine-oxidase reveals a new use for copper in forming self-derived quino-cofactor.

Azurin↗
PubMed2006

Long-term voluntary consumption of MDMA and THC in rats is modified by individual and situational factors.

Factors influencing long-term voluntary intake of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) and Delta9-tetrahydrocannabinol (THC; cannabis) were studied in a rat model. Sixty-four male Wistar rats were given free choice for 49 weeks between (1) water and MDMA solution, (2) water and THC solution or (3) water, MDMA solution and THC solution. After the first experiences with the drugs, animals of both monodrug and polydrug group developed an individually stable pattern of MDMA consumption, whereas the individual predictability of THC consumption remained poor. While THC consumption was maintained for the whole experimental period, MDMA consumption decreased with time and was nearly ceased after 3-7 months. Intake of both drugs was adapted to social changes, with THC consumption being more sensitive to social changes than MDMA consumption. In the re-test after 4 months of abstinence, all animals ceased drug consumption when the drug solutions were adulterated with bitter tasting quinine. The results show that the rats had maintained a flexible mode of drug consumption and had not become addicted. Response to novelty of the rats in test trials before the start of drug supply correlated with later MDMA intake. In conclusion, although very low amounts of MDMA and/or THC were consumed, the findings that drug-experienced animals responded differentially to a stressor and that housing conditions influenced drug intake suggests that MDMA and THC can induce psychopharmacological effects in our long-term voluntary consumption paradigm.

Animals↗
PubMedDate not supplied

Influences on fruit and vegetable consumption by low-income black American adolescents.

OBJECTIVE: The purpose of this study was to identify personal, behavioral, and environmental factors influencing fruit and vegetable consumption among 10- to 13-year-old low-income black American youth in the lower Mississippi Delta region. Social Cognitive Theory, along with other theoretical constructs, guided focus group questions and analysis. DESIGN: A qualitative study using focus group methodology. SETTING: Enrichment program of a sports summer camp for low-income youth. PARTICIPANTS: Forty-two adolescents (21 female, 21 male) participated in 6 focus groups. MAIN OUTCOME MEASURES: Personal, behavioral, and environmental influences on fruit and vegetable consumption. ANALYSIS: Content analysis methods were used by 3 independent reviewers to identify themes within the focus group transcripts. Themes were summarized and then categorized into the 3 domains of Social Cognitive Theory. RESULTS: The major themes were taste, availability, extended family influence, visual proof of the benefits of fruit and vegetable consumption, and the need for gender-specific behavioral skills. CONCLUSIONS AND IMPLICATIONS: This formative research will aid in the development of a culturally relevant nutrition intervention for low-income black American adolescents in the lower Mississippi Delta region. The results indicate that this group is more likely to respond to interventions that use role models who can provide proof that fruit and vegetable consumption is related to improved health.

Adolescent↗
PubMed1986

Auditory spaciousness: some further psychoacoustic analyses.

Psychoacoustic investigations have confirmed the known high correlation of auditory spaciousness and preference in concert-hall types of sound fields. Further, they have provided exploratory results which gave rise to the following interpretations: Auditory spaciousness is a multidimensional perceptual attribute, predominantly caused by early lateral reflections. Low-frequency reverberation may also contribute slightly, but is sensitive with respect to individual taste. All spectral components of early lateral reflections contribute to spaciousness. Spectral restriction of the reflections leads to less favorable judgments. Early lateral reflections which do not contain spectral components above about 3 kHz mainly create image expansion in the front-back direction, thus adding to the sense of envelopment of the listener. If components above about 3 kHz are present, image broadening is prominent. By means of a model of binaural signal processing which takes interaural arrival-time differences as well as interaural level differences into account, a quasiobjective measure of auditory spaciousness can be derived.

Adult↗
PubMed1989

Preparation and care of the area postrema-lesioned cat.

The area postrema (AP) is being widely studied to delineate its role in such varied functions as blood pressure regulation, conditioned taste aversion, water and energy balance, and radiation-induced emesis. This paper describes the preoperative preparation, surgical procedure, and postoperative care of cats kept long-term in which the AP was lesioned by electrocautery. A dorsal midline approach under gas anesthesia allowed access to selectively lesion the AP. Cats fully regained consciousness the same day and many became homeostatic within 24-48 h. Results of experiments using this model demonstrate the usefulness and effectiveness of the technique for model preparation.

Animals↗
PubMed2005

Youth attitudes and beliefs toward alternative tobacco products: cigars, bidis, and kreteks.

Youth use of cigars, bidis, and kreteks has spread as youth cigarette use has declined. This study investigates young people's attitudes toward and beliefs about these alternative tobacco products. The study used data from a convenience sample survey of 5,016 7th-through 12th-grade students in Massachusetts. The cigar attitudes receiving the highest endorsement levels were that cigars smell good and are something different to try, whereas the item receiving the lowest endorsement was that cigars give you a goodbuzz. The most endorsed bidi attitudes were that bid is look like joints and are something different to try. For kreteks, the most endorsed items were that kreteks smell good and are something different to try. Multivariate analyses found that reporting that these products tasted, smelled good, or were something different to try predicted use. Because the study was conducted with a convenience sample in one state, results do not necessarily generalize.

Adolescent↗
PubMed2001

Cavefish as a model system in evolutionary developmental biology.

The Mexican tetra Astyanax mexicanus has many of the favorable attributes that have made the zebrafish a model system in developmental biology. The existence of eyed surface (surface fish) and blind cave (cavefish) dwelling forms in Astyanax also provides an attractive system for studying the evolution of developmental mechanisms. The polarity of evolutionary changes and the environmental conditions leading to the cavefish phenotype are known with certainty, and several different cavefish populations have evolved constructive and regressive changes independently. The constructive changes include enhancement of the feeding apparatus (jaws, taste buds, and teeth) and the mechanosensory system of cranial neuromasts. The homeobox gene Prox 1, which is expressed in the expanded taste buds and cranial neuromasts, is one of the genes involved in the constructive changes in sensory organ development. The regressive changes include loss of pigmentation and eye degeneration. Although adult cavefish lack functional eyes, small eye primordia are formed during embryogenesis, which later arrest in development, degenerate, and sink into the orbit. Apoptosis and lens signaling to other eye parts, such as the cornea, iris, and retina, result in the arrest of eye development and ultimate optic degeneration. Accordingly, an eye with restored cornea, iris, and retinal photoreceptor cells is formed when a surface fish lens is transplanted into a cavefish optic cup, indicating that cavefish optic tissues have conserved the ability to respond to lens signaling. Genetic analysis indicates that multiple genes regulate eye degeneration, and molecular studies suggest that Pax6 may be one of the genes controlling cavefish eye degeneration. Further studies of the Astyanax system will contribute to our understanding of the evolution of developmental mechanisms in vertebrates.

Animals↗
PubMed2006

Modeling the secondary shelf life of ground roasted coffee.

This work was addressed to study the secondary shelf life of ground roasted coffee. To this purpose, fresh dark-roasted ground coffee samples were equilibrated at increasing water activity (aw) values up to 0.44 and stored at 30 degrees C for up to 1 month. To simulate home storage conditions, the headspace atmosphere was periodically perturbed by opening for a short time and then closing the packaging. The changes of some chemical and physicochemical indexes of coffee staling were studied, and sensory analysis was carried out to determine the end point of coffee acceptability. The results showed that the volatile compounds in the headspace are representative indexes of the quality depletion of roasted ground coffee during home usage. The sensory and instrumental results were used to develop a mathematical model allowing to simply and quickly calculate the secondary shelf life of coffee on the basis of its aw value at a given temperature.

Chemical Phenomena↗
PubMed1989

Ingestion of environmentally contaminated Lake Ontario salmon by laboratory rats increases avoidance of unpredictable aversive nonreward and mild electric shock.

To determine what behavioral changes are caused by consumption of Lake Ontario salmon, a 30% diet of Lake Ontario or control Pacific Ocean salmon was fed to rats for 20 days. In Experiments 1 and 2 (preference-for-predictability E-maze test), rats fed Lake Ontario salmon developed a preference for predictable food rewards more quickly than did the control rats. In Experiments 3 (passive avoidance) and 4 (conditioned suppression), rats fed Lake Ontario salmon suppressed responding to food far more after the introduction of mild electric shocks than did control rats. All results supported the hypothesis that ingestion of Lake Ontario salmon, contaminated with polychlorinated biphenyls, mercury, lead, etc., increases the reactivity of rats to aversive events. The results were successfully simulated by DMOD, a mathematical model of learning, using the assumption that rats fed Lake Ontario salmon find unpredictable nonreward and mild shock more aversive.

Animals↗
PubMed1984

Dieting. Ideology versus physiology.

The author examines the phenomenon of dieting among the general public and among patients with weight problems. Setpoint and fiscal models are discussed and developmental programs, chemical regulators, endogenous and structural changes in the central nervous system, and sensory stimuli are detailed.

Adipose Tissue↗
PubMedDate not supplied

Dose linearity testing of intravenous cefpirome (HR 810), a novel cephalosporin derivate.

After intravenous injection of single doses of 0.25, 0.5, 1.0, 1.5 and 2.0 g of cefpirome (HR 810) to 46 healthy male volunteers in an open manner, concentrations of unchanged drug were estimated at various times in serum and urine, over 24 h and 48 h, respectively. Cefpirome concentrations were determined using both high pressure liquid chromatography (HPLC) and a microbiological assay. The measurements obtained were compared by linear distribution independent regression, and were found to be equivalent. A linear relationship between dose and AUC00 (r = 0.96) for both HPLC and microbiological assay was demonstrated for the doses tested (0.25 g to 2.0 g). The biological half-life (t1/2,beta) was determined by fitting a two-compartment open model to the data: t1/2,beta was about 2 h (HPLC, median values) and was not relevantly dose dependent. A general twice daily dosing will be recommended for the treatment of infections. Clinically relevant high concentrations of unchanged cefpirome were detected in urine already after the lowest dose (0.25 g) for about 12 h, and after the highest dose (2.0 g) for at least 24 h. General tolerance was good, only slight temporary taste disturbances immediately after injection were claimed by one volunteer after both 0.5 g and 1.0 g doses and by four volunteers receiving 2.0 g of cefpirome; however, no counter-measures were needed.

Adult↗
PubMed1985

Food intake control in birds.

The regulation of food intake has been a topic of intense investigation for several decades. Most investigators have used the rat in such studies while considerably fewer studies have been conducted using birds. Research concerned with the control of food intake in birds is discussed herein. In most instances, birds and mammals have similar control mechanisms. The alimentary tract and the liver are peripheral structures which function in the control of feeding in birds but much remains to be studied as to their role. Many brain loci, including the lateral hypothalamus, ventromedial hypothalamus, striatum and olfactory bulbs are also involved in controlling food intake. Studies with birds have revealed marked breed and line differences in the response to factors modulating food intake. The bird appears to provide an excellent model for studies designed to investigate how selection for growth can alter the mechanisms involved in food intake control.

Amino Acids↗
PubMed2004

Public health aspects of food fortification: a question of balance.

Micronutrient malnutrition is widespread throughout the world, with important health and economic consequences. Tools to address this situation include food fortification, supplementation and dietary diversification, each having different and complementary roles. Fortification (mandatory and voluntary) has been practised over several decades in Western countries as well as in developing countries. Iodised salt was introduced in the USA in 1924 to reduce severe I deficiency. In 1938 voluntary enrichment of flours and breads with niacin and Fe was initiated to reduce the incidence of pellagra and Fe-deficiency anaemia respectively. Micronutrient intakes in European countries appear to be generally adequate for most nutrients. However, a number of population subgroups are at higher risk of suboptimal intakes (below the lower reference nutrient intake) for some micronutrients, e.g. folate, Fe, Zn and Ca in children, adolescents and young women. Dietary surveys indicate that fortified foods play a role in mitigating such risks for several important nutrients. The number of foods suited to fortification are considerably limited by several factors, including technological properties (notably moisture, pH and O2 permeability), leading to unacceptable taste and appearance, as well as cost and consumer expectations. In countries in which voluntary fortification is widely practised micronutrient intakes are considerably below tolerable upper intake levels. Concerns about safety are addressed in relation to the potentially increased level or proportion of fortified foods (e.g. following potential EU legislation), for nutrients with relatively low tolerable upper intake levels and where the potential benefit and risks are in different subpopulations (e.g. folic acid). Recent models for assessing these issues are discussed.

Adolescent↗
PubMedDate not supplied

Development of an instrument to assess predisposing, enabling, and reinforcing constructs associated with fat intake behaviors of low-income mothers.

OBJECTIVE: To establish reliability and construct and discriminant validity of selected factors adapted from the Health and Taste Attitudes Questionnaire developed in Finland and the Food Choice Questionnaire developed in England for use with low-income mothers in the United States. DESIGN: Cross-sectional. SETTING: Head Start and the Special Supplemental Nutrition Program for Women, Infants and Children sites in south-central Wisconsin. PARTICIPANTS: A convenience sample of 211 nonpregnant non-Hispanic black and white women. VARIABLES MEASURED: Predisposing, enabling, and reinforcing constructs of the PRECEDE-PROCEED model. ANALYSIS: Factor analyses. RESULTS: After modification, the resulting measurement models of predisposing, enabling, and reinforcing constructs demonstrated good reliability and construct and discriminant validity. These models showed excellent model fit (chi-square/df range 1.5-2.0, root mean square error of approximate range.05-.07, non-normed fit index range.97-1.0, comparative fit index range.98-1.0, incremental fit index range.98-1.0), with all factor loadings significant (P <.001). Items previously developed with European adults demonstrated different pattern structures in predisposing and enabling constructs but the same structures for reinforcing construct when applied to low-income mothers in the United States. CONCLUSION AND IMPLICATION: This modified instrument provides a tool for researchers and educators to further explore factors affecting fat intake behaviors in low-income mothers.

Adolescent↗
PubMed1997

Structure and dynamic studies by NMR of the potent sweet protein monellin and a non-sweet analog. Evidence on the importance of residue AspB7 for sweet taste.

Monellin, an intensely sweet protein and a non-sweet analog in which the AspB7 in monellin has been replaced with AbuB7 were studied by NMR. The results of our investigations show that the 3-dimensional structure of these two proteins are very similar indicating that the lack of the beta-carboxyl group in the AbuB7 analog is responsible for the loss of sweet potency. Selectively labeled monellin was prepared by solid-phase peptide synthesis by incorporating 15N-labeled amino acids into 10 key positions including AspB7. The internal mobility of these 10 key residues in monellin was estimated by the method of model-free analyses and our NMR studies show that AspB7 is the most flexible of these 10 residues. The flexibility of the AspB7 side chain may be important for receptor binding.

Amino Acid Sequence↗
PubMed2003

Medical colleges' involvement in the RNTCP: current status.

To widen access and improving the quality of TB services, involvement of medical colleges and their hospitals is paramount. The role of medical college professors in TB control as opinion leaders and role models for practising physician and as teachers imparting knowledge and skills and shaping the attitude of medical students cannot be underestimated. There is a pressing need for all medical schools to advocate DOTS and through this strategy provide the best opportunity for cure of patients. Priority activities to be undertaken by medical colleges are: (1) Training and teaching of RNTCP. (2) Service delivery of the RNTCP. (3) Advocacy of the RNTCP. (4) Operational research. A National Tast Force is being constituted comprising representatives from the zonal nodal centers, Central TB Institutes, and Central TB Division. With the establishment of zonal nodal centres and task forces at the different levels, it is envisaged that the movement will gain further momentum.

Communicable Disease Control↗
PubMed2002

Cocaine-induced suppression of saccharin intake: a model of drug-induced devaluation of natural rewards.

In Experiment 1, water-deprived Sprague-Dawley rats were given 5 min access to saccharin. This tube retracted, an empty tube advanced, and the rats were given 1 hr to lick the empty tube on a fixed-ratio 10 lick contingency to self-administer saline or cocaine (0.33 mg/infusion) via an intravenous catheter. The results showed that rats avoided intake of saccharin after saccharin-cocaine pairings and that greater avoidance of the gustatory cue was associated with greater cocaine self-administration. In Experiment 2, a similar dose-response function was obtained with either the empty tube or a lever as the operant. In Experiment 3, avoidance of the saccharin cue and the propensity to self-administer cocaine were maintained after at least 1 month of abstinence. As such, this paradigm may be useful as a model of cue-induced craving and drug-induced devaluation of natural rewards.

Administration, Oral↗