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At least 541 records · Page 30Linked to original sources
PubMed2006

Experimental manipulations of microbial food web interactions in a humic lake: shifting biological drivers of bacterial community structure.

A previous multiyear study observed correlations between bacterioplankton community composition (BCC) and abundance and the dynamics of phytoplankton populations and bacterivorous grazers in a humic lake. These observations generated hypotheses about the importance of trophic interactions (both top-down and bottom-up) for structuring bacterial communities in this lake, which were tested using two multifactorial food web manipulation experiments that separately manipulated the intensity of grazing and the composition of the phytoplankton community. Our results, combined with field observations, suggest that a hierarchy of drivers structures bacterial communities in this lake. While other studies have noted links between aggregate measures of phytoplankton and bacterioplankton communities, we demonstrate here correlations between succession of phytoplankton assemblages and BCC as assessed by automated ribosomal intergenic spacer analysis (ARISA). We used a novel approach linking community ARISA data to phylogenetic assignments from sequence analysis of 16S rRNA gene clone libraries to examine the responses of specific bacterial phylotypes to the experimental manipulations. The synchronous dynamics of these populations suggests that primary producers may mediate BCC and diversity through labile organic matter production, which evolves in quality and quantity during phytoplankton succession. Superimposed on this resource-mediated control of BCC are brief periods of intense bacterivory that impact bacterial abundance and composition.

Animals↗
PubMed1992

Nutrition and the quality of life: a measure for the outcome of nutritional intervention.?

The quality of life in old age is dependent on many resources and not just on health. Quality of life cannot be a measure for the outcome of nutritional interventions in old age. Risk patterns shift with advancing age and the outcome of a nutritional intervention may have to be evaluated under different circumstances. Although the impact of nutrition as a preventive measure decreases with age, the value of food intake for social structure, self-esteem, enjoyment, and situation awareness gradually increases.

Adaptation, Physiological↗
PubMed2000

Regulations on statements made for dietary supplements concerning the effect of the product on the structure or function of the body; partial stay of compliance. Food and Drug Administration, HHS. Final rule; partial stay of compliance.

The Food and Drug Administration (FDA) is announcing a partial stay of compliance for the final rule defining the types of statements that can be made concerning the effect of a dietary supplement on the structure or function of the body for certain dietary supplement products. Dietary supplement products that were labeled, or for which labeling had been printed, on or before January 6, 2000, the publication date of the final rule, are eligible for the stay. This action is in response to two petitions for stay and reconsideration.

Body Composition↗
PubMed2002

Australia's food regulations--challenges for public health advocacy.

OBJECTIVE: To illustrate current challenges to public health advocacy through examining the case of the development of food regulations in Australia. METHOD: To present a case study of the recent changes to the structures for the development of food regulations in Australia and aspects of the new Food Standards Code that have direct relevance to public health. RESULTS: Clear links between the policy setting structure and some types of public health advocacy strategies are made. CONCLUSIONS AND RECOMMENDATIONS: The challenge for public health advocacy is to ensure that professional associations as well as individual health professionals are cognisant of the environment within which public policy is developed, as well as being able to professionally comment on the content of public policy, for positive impacts on public health priorities to be achieved.

Australia↗
PubMed2000

Simple rules yield complex food webs.

Several of the most ambitious theories in ecology describe food webs that document the structure of strong and weak trophic links that is responsible for ecological dynamics among diverse assemblages of species. Early mechanism-based theory asserted that food webs have little omnivory and several properties that are independent of species richness. This theory was overturned by empirical studies that found food webs to be much more complex, but these studies did not provide mechanistic explanations for the complexity. Here we show that a remarkably simple model fills this scientific void by successfully predicting key structural properties of the most complex and comprehensive food webs in the primary literature. These properties include the fractions of species at top, intermediate and basal trophic levels, the means and variabilities of generality, vulnerability and food-chain length, and the degrees of cannibalism, omnivory, looping and trophic similarity. Using only two empirical parameters, species number and connectance, our 'niche model' extends the existing 'cascade model and improves its fit ten-fold by constraining species to consume a contiguous sequence of prey in a one-dimensional trophic niche.

Ecology↗
PubMed2005

Kimchi and soybean pastes are risk factors of gastric cancer.

AIM: This case-control study investigated the effects of kimchi, soybean paste, fresh vegetables, nonfermented alliums, nonfermented seafood, nonfermented soybean foods, and the genetic polymorphisms of some metabolic enzymes on the risk of gastric cancer in Koreans. METHODS: We studied 421 gastric cancer patients and 632 age- and sex-matched controls. Subjects completed a structured questionnaire regarding their food intake pattern. Polymorphisms of cytochrome P450 1A1 (CYP1A1), cytochrome P450 2E1 (CYP2E1), glutathione S-transferase mu 1 (GSTM1), glutathione S-transferase theta 1 (GSTT1) and aldehyde dehydrogenase 2 (ALDH2) were investigated. RESULTS: A decreased risk of gastric cancer was noted among people with high consumption of nonfermented alliums and nonfermented seafood. On the other hand, consumption of kimchi, and soybean pastes was associated with increased risk of gastric cancer. Individuals with the CYP1A1 Ile/Val or Val/Val genotype showed a significantly increased risk for gastric cancer. Increased intake of kimchi or soybean pastes was a significant risk factor for the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the GSTM1 non-null, the GSTT1 non-null, or the ALDH2 *1/*1 genotype. In addition, eating soybean pastes was associated with the increased risk of gastric cancer in individuals with the GSTM1 null type. Nonfermented alliums were significant in individuals with the CYP1A1 Ile/Ile, the CYP2E1 c1/c2 or c2/c2, the GSTT1 null, the GSTT1 non-null, or the ALDH2 *1/*2 or *2/*2 genotype, nonfermented seafood was those with the CYP1A1 Ile/Ile, the CYP2E1 c1/c1, the ALDH2 *1/*1 genotype or any type of GSTM1 or GSTT1. In homogeneity tests, the odds ratios of eating kimchi for gastric cancer according to the GSTM1 or GSTT1 genotype were not homogeneous. CONCLUSION: Kimchi, soybean pastes, and the CYP1A1 Ile/Val or Val/Val are risk factors, and nonfermented seafood and alliums are protective factors against gastric cancer in Koreans. Salt or some chemicals contained in kimchi and soybean pastes, which are increased by fermentation, would play important roles in the carcinogenesis of stomach cancer. Polymorphisms of the CYP1A1, CYP2E1, GSTM1, GSTT1, and ALDH2 genes could modify the effects of some environmental factors on the risk of gastric cancer.

Adult↗
PubMed2000

Optimal intraguild foraging and population stability.

This article explores effects of adaptive intraguild predation on species coexistence and community structure in three species' food webs. Two Lotka-Volterra models that assume a trade-off between competition and predation strength are considered in detail. The first model does not explicitly model resource dynamics and is considered with both nonadaptive and adaptive intraguild predation; in the latter case predators choose their diet in order to maximize their instantaneous population growth rate. The second model includes resource population dynamics. Effects of adaptive intraguild predation on the community structure along a gradient in environment productivity are analyzed and compared with some experimental results of protist food webs. Conditions under which intraguild predation is adaptive are discussed for both models. It is proved that if intraguild predators are perfect optimizers then intraguild predation should decrease with increasing environmental productivity and adaptive intraguild predation is a stabilizing factor provided environmental productivity is high enough.

Adaptation, Biological↗
PubMed2003

Adherence practices among people living with HIV.

This paper offers a critique of patient-deficit models of adherence by examining the articulation of dosing schedules and food prohibitions with the structure of everyday lives. Interviews with 31 men and 4 women taking HAART show that doses associated with regular daily life events are most consistently taken, but many individuals rework official dosing guidelines around timing and food consumption. Barriers to adherence often arise from conflicting demands imposed by work schedules, different medications, food prohibitions, and even outright discrimination as in the case of US immigration policy. Adherence may be the outcome of compromises made in an effort to solve contradictory demands, and may be situational and related to the qualities of particular drugs, as much as to personality traits. Autobiographical narratives that give order to one's sense of self provide foundations upon which adherence decision making occurs. Finally, perceptions of drug effectiveness may lead to self-reinforcing adherence practices.

Activities of Daily Living↗
PubMed1992

Chronic upper abdominal pain: site and radiation in various structural and functional disorders and the effect of various foods.

Pain site and radiation and the effect of various foods were studied prospectively in a consecutive series of patients with chronic upper abdominal pain. Patients followed for less than one year were excluded unless peptic ulcer or abdominal malignancy had been diagnosed or laparotomy had been carried out. A total of 632 patients were eligible for the first study and 431 for the second. Gastric ulcer pain was more likely to be left hypochondrial (17%) compared with pain from duodenal ulcer (4%) or from all other conditions (5%). It was less likely to be epigastric (54%) compared with duodenal ulcer pain (75%). Oesophageal pain was more likely to be both retrosternal and epigastric (25%) compared with non-oesophageal pain (2%). Radiation to the back was more common in peptic ulcer (31%) and biliary pain (35%) compared with functional pain (20%). Pain precipitation by fatty foods was commoner in biliary disease (40%) than in duodenal ulcer (11%), peptic ulcer (9%), or non-ulcer dyspepsia (19%). Orange, alcohol, and coffee precipitated pain more frequently in duodenal ulcer (41%, 50%, and 43% respectively) than in biliary disease (17%, 0%, and 14% respectively). Chilli precipitated pain in one quarter to one half of subjects regardless of diagnosis. Approximately one tenth of all subjects avoided chilli, curry, coffee, and tea because of medical or other advice.

Abdominal Pain↗
PubMed2004

[Risk factors and etiological structure of children's cross-allergic reactions to food products].

Authors of article have recently analyzed the frequency of prevalence and risk factors of cross-reactivity to foodstuffs among 239 children of Abakan in the age of from 6 months till 15 years with skin, respiratory and combined manifestation of atopy. It was proved that risk factors of development of cross-reactivity to food among children of the first years of life are hereditary predisposition to allergic diseases (77.8%) and early introductions of supplemental feeding (44%). Among children older then 7 years pollen sensitization (62%) which preceded the development of cross allergic reactions between separate foodstuffs reaches up to 73.7%, between pollen and foodstuff up to 79% and between epidermal and food up to 10.1%.

Adolescent↗
PubMed1997

[Important cross-reactive allergens].

Food allergy in adults is mainly due to cross-reactivity between inhalative and food allergens. IgE antibodies are induced against aero-allergens, which recognize a structurally similar component in certain foods. Not all patients with such food allergies have clinical symptoms of pollinosis, although a sensitization to the inducing aero-allergens is always found. Dependent on the main allergen, namely Bet v 1 or Bet v 2, different symptoms can be observed. Bet v 1 mainly causes mild symptoms localized around the area of the oropharynx (oral allergy syndrome). It is mainly caused by apples, cherries, peaches and plums, but can also be observed with other allergens which cause generalized symptoms. Sensitization to Bet v 2 is commonly associated with more generalized symptoms, in particular urticaria and angioedema (mugwort/celery syndrome). Recently, new cross-reactivities have been detected based on latex sensitivity or housedust mite sensitivity. Latex allergy can cause food allergy to avocado, banana and chestnut, housedust mite allergens to crustacea and snails. Knowledge of these cross-reactivities is important for the clinician, since the majority of food allergies are caused by such cross-reactive IgE-antibodies. Further characterization of these allergens may open up ways of inducing tolerance to these substances.

Allergens↗
PubMed2000

Evaluating whether velar lobe size indicates food limitation among larvae of the marine gastropod Crepidula fornicata.

Disproportionately large feeding structures have been used to infer food limitation in some marine invertebrate larvae, but few studies have investigated whether other factors alter larval morphology in similar ways. In this study, larvae of Crepidula fornicata were reared either at five different food concentrations of Isochrysis galbana (clone T-ISO) at a single temperature (22 degrees C) (Experiments I and II); or on three different phytoplankton species (Isochrysis galbana, Dunaliella tertiolecta, and Pavlova lutheri) at both high and low concentrations at a single temperature (22 degrees C) (Experiment III); or at high and low concentrations of Isochrysis galbana at four different temperatures between 16 and 25 degrees C (Experiment IV). Shell lengths and velar lobe dimensions were determined for individual larvae at intervals to monitor relative rates of velar and shell growth. In addition (Experiment V), fast growing and slow growing larvae in Experiment I were examined separately to determine whether velar lobes developed at similar rates (relative to shell growth) for fast and slow growing larvae within individual cultures. In general, velar lobes grew significantly larger, relative to shell length, when larvae were reared at low food concentrations (P<0.0001); for larvae of similar shell length, the velar lobes of those fed 1x10(4) cells ml(-1) were on average 17.7% larger than those of larvae fed 18x10(4) cells ml(-1) of T-ISO. In contrast, larvae fed different phytoplankton species at equivalently high food concentrations did not differ in relative velum size (P=0.2666), even though shell growth rates differed significantly for larvae raised on the different diets, indicating substantial variation in food quality. We also found that relative rates of velum and shell growth differed among fast and slow growing individuals within treatments. Temperature had no significant effect on relative rates of velar and shell growth within the 16-25 degrees C range tested (P=0.121), but may have altered the relationship between food concentration and relative velar growth. These results indicate that dramatically reduced food concentration induces disproportionate growth in the velar lobes of C. fornicata, but that interpretation of data from field-collected individuals of this species will be made difficult by the potentially confounding effects of temperature, food quality, and differences in individual growth potential. Assessments of food limitation using morphological measurements for field-collected larvae will need to be supplemented with other indicators before convincing conclusions about the extent of food limitation in C. fornicata can be drawn.

Journal Article↗
PubMed2005

Body size in ecological networks.

Body size determines a host of species traits that can affect the structure and dynamics of food webs, and other ecological networks, across multiple scales of organization. Measuring body size provides a relatively simple means of encapsulating and condensing a large amount of the biological information embedded within an ecological network. Recently, important advances have been made by incorporating body size into theoretical models that explore food web stability, the patterning of energy fluxes, and responses to perturbations. Because metabolic constraints underpin body-size scaling relationships, metabolic theory offers a potentially useful new framework within which to develop novel models to describe the structure and functioning of ecological networks and to assess the probable consequences of biodiversity change.

Journal Article↗
PubMed1995

Interactions between food components and drugs. Part 3. Interactions between pectin and propranolol.

Bioavailability of drugs can be affected distinctly by interactions with food components. Effects of structural parameters of the soluble dietary fiber pectin on lipid-membrane transport of propranolol (1) was investigated in vitro using a two-compartment model with a dodecanol-collodium membrane at pH 7.2 and 37 degrees C. Starting from practically fully esterified citrus pectin two series of defined and in their structural parameters gradually varied pectins were prepared. In presence of pectins with a blockwise distribution of free COOH-groups the portion of permeated 1 is significantly diminished with a decreasing degree of esterification (DE). On the other hand, only in the smallest DE pectins having statistically distributed free COOH-groups seemed to affect the transport rate of 1. The viscosity of the tested pectins possessed no significant influence on the passage of 1.

Biological Availability↗
PubMed2005

Consumer food safety knowledge, practices, and demographic differences: findings from a meta-analysis.

Risk communication and consumer education to promote safer handling of food can be the best way of managing the risk of foodborne illness at the consumer end of the food chain. Thus, an understanding of the overall status of food handling knowledge and practices is needed. Although traditional qualitative reviews can be used for combining information from several studies on specific food handling behaviors, a structured approach of meta-analysis can be more advantageous in a holistic assessment. We combined findings from 20 studies using meta-analysis methods to estimate percentages of consumers engaging in risky behaviors, such as consumption of raw food, poor hygiene, and cross-contamination, separated by various demographic categories. We estimated standard errors to reflect sampling error and between-study random variation. Then we evaluated the statistical significance of differences in behaviors across demographic categories and across behavioral measures. There were considerable differences in behaviors across demographic categories, possibly because of socioeconomic and cultural differences. For example, compared with women, men reported greater consumption of raw or undercooked foods, poorer hygiene, poorer practices to prevent cross-contamination, and less safe defrosting practices. Mid-age adults consumed more raw food (except milk) than did young adults and seniors. High-income individuals reported greater consumption of raw foods, less knowledge of hygiene, and poorer cross-contamination practices. The highest raw ground beef and egg consumption and the poorest hygiene and cross-contamination practices were found in the U.S. Mountain region. Meta-analysis was useful for identifying important data gaps and demographic groups with risky behaviors, and this information can be used to prioritize further research.

Adolescent↗
PubMed2002

Variables influencing food perception reviewed for consumer-oriented product development.

Consumer wishes have to be translated into product characteristics to implement consumer-oriented product development. Before this step can be made, insight in food-related behavior and perception of consumers is necessary to make the right, useful, and successful translation. Food choice behavior and consumers' perception are studied in many disciplines. Models of food behavior and preferences therefore were studied from a multidisciplinary perspective. Nearly all models structure the determinants related to the person, the food, and the environment. Consequently, the overview of models was used as a basis to structure the variables influencing food perception into a model for consumer-oriented product development. To this new model, referred to as food perception model, other variables like time and place as part of consumption moment were added. These are important variables influencing consumers' perception, and therefore of increasing importance to consumer-oriented product development nowadays. In further research, the presented food perception model is used as a tool to implement successful consumer-oriented product development.

Choice Behavior↗