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PubMed1995

Domoic acid-induced neuronal degeneration in the primate forebrain revealed by degeneration specific histochemistry.

Domoic acid is a potent excitotoxin produced by diatoms which is subsequently passed along the marine food chain. Its chemical structure and toxicological properties are similar to kainic acid. Like kainic acid, exposure results in extensive hippocampal degeneration. The effect of domoic acid on other primate brain structures, however, is less resolved. In an attempt to clarify this issue, the present study applied a degeneration specific histochemical technique (de Olmos' cupric-silver method) to reveal degeneration within the brains of domoic acid-dosed cynomolgus monkeys. Degenerating neuronal cell bodies and terminals were found not only within the hippocampus, but also within a number of other 'limbic' structures including the entorhinal cortex, the subiculum, the piriform cortex, the lateral septum, and the dorsal lateral nucleus of the thalamus. Although the hippocampus is a component of the original limbic circuit of Papez, other components such as the mammillary bodies, the anterior nucleus of the thalamus and the cingulate cortex contained no degeneration, while a number of more recently documented efferent targets of the hippocampal formation revealed extensive degeneration. The pattern of degeneration generally correlated with those regions containing high densities of kainate receptors.

Animals↗

PubMed1994

The origins of parasitism in the platyhelminthes.

Symbiotic associations have arisen independently in several groups of the largely free-living turbellarians. Morphological adaptations of turbellarians to a symbiotic way of life include suckers and adhesive glands for attachment, elaborate systems of microvilli and other epidermal structures for absorption of food, glands for the formation of cysts, cocoons and cement material, and lack of a pharynx and intestine in some species. However, many species closely resemble their free-living relatives. Egg production is greatly increased at least in some species, and life cycles are always direct. Food of symbiotic turbellarians consists of host food and/or host tissue. Ectosymbiotes show fewer physiological adaptations than entosymbiotes. The major groups of parasitic Platyhelminthes (Trematoda Aspidogastrea, Trematoda Digenea, Monogenea, Udonellidea, Cestoda including Gyrocotylidea, Amphilinidea and Eucestoda), form one monophylum, the Neodermata, characterized by a neodermis (tegument) replacing the larval epidermis, epidermal cilia with a single horizontal rootlet, sensory receptors with electron-dense collars, spermatozoa with axonemes incorporated in the sperm body by proximodistal fusion, and protonephridial flame bulbs formed by two cells each contributing a row of longitudinal ribs to the filtration apparatus. The sister group of the Neodermata is unknown but is likely to be a large taxon including the Proseriata and some other turbellarian groups. Among the Neodermata, the Aspidogastrea is likely to be the most archaic group, as indicated by DNA studies, morphology, life cycles and physiology. Aspidogastreans can survive for many days or even weeks outside a host in simple media, they show little host specificity, and have an astonishingly complex nervous system and many types of sensory receptors, both in the larva and the adult. It is suggested that Aspidogastrea were originally parasites of molluscs (and possibly arthropods and other invertebrates) and that they are archaic forms which have remained at a stage where vertebrates represent facultative hosts or obligatory final hosts into which only the very last stages of the life cycle (maturation of the gonads) have been transferred. The complex life cycles of Digenea have evolved from the simple aspidogastrean ones by intercalation of multiplicative larval stages (sporocysts, rediae) in the mollusc host, and of cercarial stages ensuring dispersal to the now obligatory final host. Monogenea may have lost the molluscan host or evolved before the early neodermatans had acquired it. Cestoda either replaced the original molluscan with an arthropod host, retained an original arthropod host or evolved from an early neodermatan before molluscan hosts had been acquired, newly acquiring an arthropod host.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1985

Evolve II: a computer model of an evolving ecosystem.

The Evolve II program is a model of an ecosystem in which organisms are allowed to evolve. Organisms are subject to a changeable environment and competition from other organisms for a limited food supply. The gene structure may change through mutation. A feature of Evolve II is that the magnitude of phenotypic change resulting from mutation is itself a property of the gene. The system was studied under a number of environmental variation schemes. We report three significant findings. Two species (lineages with distinctly different survival strategies) evolved and coexisted in the same environmental conditions. Organisms developed a resistance to phenotypic change in response to mutation in slowly varying environments. However, traits which favor survival of the individual at the expense of reproduction could in some cases undergo phenotypic change in response to mutation despite the fact that this did not favor the survival of the offspring. This demonstrates that gene structures can evolve which are advantageous from the standpoint of the lineage, but not advantageous from the standpoint of individual offspring.

Aging↗

PubMed1982

Lateral hypothalamic injection of bombesin decreases food intake in rats.

The effect of lateral hypothalamic injections of bombesin on feeding behavior was examined. Rats equipped with stainless steel cannulas directed toward the lateral hypothalamus received bilateral injections of bombesin prior to access to a liquid test diet after a 3 hr food deprivation. Bombesin in doses of 5 ng, 50 ng and 100 ng produced significant reductions in the size of the first meal. Injection of 50 ng of the biologically weak analogue [D-Trp8] bombesin had no effect. Injection of 5 ng or 50 ng of bombesin had no effect on deprivation-induced water intake, and injection of 50 ng of bombesin had no effect on body temperature. The food and water intake data and direct quantitative behavioral measures indicated that lateral hypothalamic injections of bombesin specifically reduced food intake. The structure-activity relationship for this effect was similar to those for other actions of bombesin. A bombesin-like peptide in the lateral hypothalamus or its receptors may play a role in postprandial satiety.

Animals↗

PubMed2005

Relationships between the Food Expectancy Questionnaire (FEQ) and the Food Frequency Questionnaire (FFQ).

The outcome expectancies of 250 respondents were examined using the Food Expectancy Questionnaire (FEQ), comparing expectancies about four different foods: fruit, vegetables, chocolate and sweets and plain biscuits. These expectancies were related to diet as assessed by a Food Frequency Questionnaire. As with alcohol expectancies [Jones, B. T., Corbin, W. & Fromme, K. (2001). A review of expectancy theory and alcohol consumption. Addiction, 96, 57-72], on which this research was modelled, positive and negative outcomes were the main factors for all foods, accounting jointly for between 33 and 40% of expectancy variance in factor analysis and predicting as much as 16% of the variance in relevant food intake measures by linear regression. Expected positive and negative outcomes of eating were predominantly immediate psychological after-effects, rather than including orosensory experiences, or longer-term effects on health or well-being. Other expectancies varied from food to food. FEQ expectancies for different foods have similar factor structure and were related to self-reported diet, the FEQ therefore shows promise as a means of modelling cognitions about eating.

Adolescent↗

PubMed2006

Nutritional disorders in the elderly.

Undernutrition is common in older people and has serious adverse effects. Weight loss and low body weight are key markers. Correctable causes, such as depression, are common and should be sought. Structured efforts to encourage food intake, together with nutritional supplements, often are of benefit. It is hoped that a better understanding of the underlying mechanisms will lead to targeted treatments. Overweight and obesity also are common in older people, and are associated with morbidity and impaired function. It is probably appropriate to recommend weight loss to obese older people who have associated comorbidities, particularly reduced mobility, but seldom, if ever, for increased weight alone.

Aged↗

PubMed1999

Cholesterol lowering with high-viscosity hydroxypropylmethylcellulose.

Hydroxypropylmethylcellulose (HPMC) is a food gum having several structural and functional properties in common with hypocholesterolemic soluble fibers. The safety and cholestero-lowering efficacy of HPMC, incorporated into a National Cholesterol Education Program Step I diet, was compared with placebo in patients with mild to moderate hypercholesterolemia. After an 8-week National Cholesterol Education Program Step I dietary lead-in phase, 160 patients with low-density lipoprotein (LDL) cholesterol between 130 and 200 mg/dl and triglycerides <300 mg/dl were randomized to placebo, 2.5, 5.0, or 7.5 g/day of HPMC for a 6-week treatment period. Patients returned to the clinic every 2 weeks for lipid measurements and safety assessments. HPMC significantly lowered total, LDL, and non-high-density lipoprotein (HDL) cholesterol. LDL cholesterol concentrations (average of weeks 4 and 6) decreased by 3.0% (4.9 mg/dl), 5.9% (10.3 mg/dl), 12.1% (20.4 mg/dl), and 11.7% (20.3 mg/dl) from baseline levels in the placebo and 2.5, 5.0, and 7.5 g/day HPMC treatment groups, respectively. Statistically significant (p<0.05) reductions in LDL cholesterol were observed in the 5.0 and 7.5 g/day HPMC groups compared with placebo and 2.5 g/day HPMC treatment groups. Total and non-HDL cholesterol responses paralleled those of LDL cholesterol. There were no significant differences between the treatment groups in HDL cholesterol or triglyceride responses, incidence of adverse experiences, or gastrointestinal-related adverse experiences. These results suggest that HPMC is a well-tolerated and effective adjunct to diet for lowering LDL cholesterol in patients with mild to moderate hypercholesterolemia.

Adult↗

PubMed2003

Time to eat: the relationship between the number of people eating and meal duration in three lunch settings.

We conducted an observational study of customers in three different types of lunch settings: a worksite cafeteria, a fast-food restaurant, and a moderately priced restaurant, and assessed the relationship between meal duration and the number of people eating at each table (group size). Results suggest a significant positive correlation between group size and meal duration, collapsing over eating settings. Analysis of variance yielded significant main effects of both eating setting and of group size, indicating that meal durations were longest in the moderately priced restaurant and shortest in the fast-food restaurant. An interaction between group size and eating setting indicates that the magnitude of the group size effect on meal duration differed in the different situations, with the effect of group size on duration being smallest, but still significant, in the fast-food setting compared with the other two settings.

Eating↗

PubMed1996

Clinical characteristics and diagnostic delay of head and neck cancer: results from a prospective study in Belgium.

A prospective study of head and neck cancer patients was started to gather information about topographic and clinical characteristics of head and neck cancer, alcohol and nicotine abuse and the delay in diagnosis. More than half of the patients consulted our institution with an advanced stage of disease. As was expected, we found a positive association between the size of the tumour and the clinical stage of the neck. Concerning nicotine and alcohol abuse, our results support the hypothesis that tobacco smoking is more strongly associated with lesions in sites heavily exposed to inhaled smoke, whereas alcohol consumption has a stronger effect on structures belonging to the 'food channel' and reservoir systems. We found no association between delay and tumour stage at diagnosis, but a statistically significant correlation was found between the delay and the tumour site. This leads us to conclude that the tumour stage is determined mostly by the biology of the tumour.

Adult↗

PubMed2000

Polyphenolic composition of raisins.

The polyphenolics of raisins were extracted, separated by HPLC, and characterized by their UV-vis spectra, and their concentrations measured. Color measurements and browning indices were also determined. Samples (n = 20) included sun-dried, dipped, and golden raisins. Comparisons were also made with fresh and frozen Thompson Seedless grapes. Golden raisins (which are treated with SO(2)) had the highest amount of hydroxycinnamic acids and the highest lightness values. In comparison with fresh grapes, percent losses of the two major hydroxycinnamics (caftaric and coutaric acids) in sun-dried, dipped, and golden raisins were on the order of 90%. Flavonols were not influenced by processing as much as hydroxycinnamics, while procyanidins and flavan-3-ols were completely degraded in all raisin samples. Formation of hydroxymethylfurfural and loss of amino acids in sun-dried and dipped raisins are ascribed to Maillard browning reactions.

Chromatography, High Pressure Liquid↗

PubMed2001

Reaction of tryptophan with carbohydrates: mechanistic studies on the formation of carbohydrate-derived beta-carbolines.

Numerous carbohydrate-derived beta-carbolines have been identified for the first time in model reactions of tryptophan with glucose and ribose, as well as in food samples. Extending these structural studies, we performed detailed investigations to elucidate the corresponding intermediates and formation pathway of these alkaloids. Degradation experiments with purified tryptophan glycoconjugates established that only glyco-tetrahydro-beta-carboline-3-carboxylic acids, and not the N-glycosides nor the C-glycoconjugates represented the direct precursors of carbohydrate-derived beta-carbolines. In addition, the significance of the oxidative decarboxylation reaction as the initial step for formation of 1-substituted beta-carbolines was proven. Finally, the stereochemistry of the carbohydrate-derived side chain was studied by means of CD spectroscopy and HPLC-CD experiments. These detailed stereochemical analyses yielded experimental evidence for the racemization steps required for formation of the carbohydrate-derived harman alkaloids and confirmed the proposed reaction pathway.

Carbohydrates↗

PubMedDate not supplied

Retention of memory traces in rats subjected to 10 minutes of clinical death.

Studies of the effects of 10-min clinical death in mongrel rats, induced by complete circulatory arrest, on the mechanisms of memory, showed that the content of already formed memories ("what to do?"), i.e., the structure of a food-procuring habit, motivational activity, and the level of organization of behavior, was completely retained 12 days after resuscitation regardless of how many traces were formed before the experimental procedure. Transient changes seen after clinical death mainly affected the process of performing the habit ("how to do it?"): there was a decrease in the ability to work, along with degradation of performance parameters such as readiness, mobilization activity, and the stability with which memory traces were performed. The rate of recovery of these aspects depended on the initial level of conditioned reflex activity in the rats: the higher this level, the more rapidly the performance parameters returned to the baseline level. It is suggested that these disturbances in the process of reproduction were non-specific in nature and could be due to the post-operative hyperexcitability of the animals.

Animals↗

PubMed2004

Why were polysaccharides necessary?

The main idea of this paper is that the primordial soup may be modelled by food systems whose structure-property relationship is based on non-specific interactions between denatured biopolymers. According to the proposed hypothesis, polysaccharides were the first biopolymers that decreased concentration of salts in the primordial soup, 'compatibilised' and drove the joint evolution of proto-biopolymers. Synthesis of macromolecules within the polysaccharide-rich medium could have resulted in phase separation of the primordial soup and concentration of the polypeptides and nucleic acids in the dispersed phase particles. The concentration of proto-biopolymer mixtures favoured their cross-linking in hybrid supermacromolecules of conjugates. The cross-linking of proto-biopolymers could occur by hydrophobic, electrostatic interactions, H-bonds due to freezing aqueous mixed biopolymer dispersions and/or by covalent bonds due to the Maillard reaction. Cross-linking could have increased the local concentration of chemically different proto-biopolymers, fixed their relative positions and made their interactions reproducible. Attractive-repulsive interactions between cross-linked proto-biopolymer chains could develop pairing of the monomer units, improved chemical stability (against hydrolysis) and led to their mutual catalytic activity and coding. Conjugates could probably evolve to the first self-reproduced entities and then to specialized cellular organelles. Phase separation of the primordial soup with concentration of conjugates in the dispersed particles has probably resulted in proto-cells.

Biopolymers↗

PubMedDate not supplied

Bioactivation of zearalenone by porcine hepatic biotransformation.

Zearalenone (ZEA) is a resorcylic acid lactone derivative produced by various Fusarium species that are widely found in food and feeds. The structure of zearalenone is flexible enough to allow a conformation able to bind to mammalian oestrogen receptors, where it acts as an agonist. Using oestrogen-dependent Human Breast Cancer (MCF-7) cells, the oestrogenic activity of zearalenone and its derivatives were compared using 17 beta-oestradiol as a positive control. The results obtained demonstrate that the oestrogenic potency of ZEA derivatives could be ranked in the following order: alpha-zearalenol > alpha-zearalanol > zearalenone > beta-zearalenol. Since pigs have been reported to be among the most sensitive animal species, biotransformation studies with pig liver subcellular fractions were conducted. These studies indicated that alpha-zearalenol is the main hepatic metabolite of zearalenone in pigs, and it is assumed that 3 alpha- and 3 beta-hydroxysteroid dehydrogeneases are involved in the hepatic biotransformation, since the formation of alpha-zearalenol and beta-zearalenol could be inhibited by prototypic substrates for either enzyme. The bioactivation of ZEA into the more active alpha-zearalenol seems to provide a possible explanation for the observed high sensitivity of pigs towards feeding-stuffs contaminated with the mycotoxin.

Animals↗

PubMed2006

Climate change, parasitism and the structure of intertidal ecosystems.

Evidence is accumulating rapidly showing that temperature and other climatic variables are driving many ecological processes. At the same time, recent research has highlighted the role of parasitism in the dynamics of animal populations and the structure of animal communities. Here, the likely interactions between climate change and parasitism are discussed in the context of intertidal ecosystems. Firstly, using the soft-sediment intertidal communities of Otago Harbour, New Zealand, as a case study, parasites are shown to be ubiquitous components of intertidal communities, found in practically all major animal species in the system. With the help of specific examples from Otago Harbour, it is demonstrated that parasites can regulate host population density, influence the diversity of the entire benthic community, and affect the structure of the intertidal food web. Secondly, we document the extreme sensitivity of cercarial production in parasitic trematodes to increases in temperature, and discuss how global warming could lead to enhanced trematode infections. Thirdly, the results of a simulation model are used to argue that parasite-mediated local extinctions of intertidal animals are a likely outcome of global warming. Specifically, the model predicts that following a temperature increase of less than 4 degrees C, populations of the amphipod Corophium volutator, a hugely abundant tube-building amphipod on the mudflats of the Danish Wadden Sea, are likely to crash repeatedly due to mortality induced by microphallid trematodes. The available evidence indicates that climate-mediated changes in local parasite abundance will have significant repercussions for intertidal ecosystems. On the bright side, the marked effects of even slight increases in temperature on cercarial production in trematodes could form the basis for monitoring programmes, with these sensitive parasites providing early warning signals of the environmental impacts of global warming.

Animals↗

PubMed1983

Effect of dietary modification on the enhanced uptake of cholesterol in diabetic rats.

Previous studies have demonstrated an enhanced intestinal uptake (Jd) of nutrients in diabetes mellitus in the rat, and the present studies were undertaken to determine the effect of dietary modifications on the Jd of cholesterol. In control rats, cholesterol Jd was highest in animals fed a low cholesterol diet, and lowest in those fed a high protein diet. Cholesterol Jd was highest in diabetic animals fed a high carbohydrate diet. Cholesterol Jd was higher in diabetic than in control rats only when they were fed the high carbohydrate diet; cholesterol Jd was similar in diabetic and control animals fed a high cholesterol, high protein, or low protein diet, and was lower in diabetic than control rats fed a low cholesterol diet. These changes in cholesterol Jd were not explained by differences in parameters of intestinal structure, weight gain, or food consumption. Thus the differences in cholesterol Jd observed between diabetic and control animals may be modified by varying the composition of the diet, and avoiding a high carbohydrate diet prevents the enhanced Jd of cholesterol in drug-induced diabetes mellitus.

Animals↗

PubMed1998

Effect of a stearic acid-rich, structured triacylglycerol on plasma lipid concentrations.

BACKGROUND: Structured lipids are being incorporated into foods to reduce their energy value. One such lipid is rich in stearic acid. OBJECTIVE: The objective of this study was to compare the effects on plasma lipids of a stearic acid-rich triacylglycerol and a fat rich in palmitic acid in hypercholesterolemic subjects. DESIGN: Fifteen subjects with an average plasma cholesterol concentration of 6.13 +/- 0.80 mmol/L initially ate a low-fat diet for 2 wk (run-in period), followed in random order and blinded fashion by 2 high-fat diets (for 5 wk each) containing foods derived from margarines rich either in palmitic acid or in the structured, stearic acid-rich triacylglycerol. RESULTS: Plasma cholesterol concentrations with the low-fat, the stearic acid-rich, and the palmitic acid-rich diets were not significantly different (5.35 +/- 0.83, 5.41 +/- 0.78, and 5.52 +/- 0.68 mmol/L, respectively) but were significantly lower (P < 0.001) than those measured during the habitual diet period (ie, 2 wk before the study began). Neither HDL cholesterol nor plasma triacylglycerol differed significantly among the 3 study diets. CONCLUSION: A similar increase in the intake of stearic and palmitic acids (differing by approximately 5% of total energy) to ensure a high fat intake resulted in plasma total and LDL-cholesterol concentrations that did not differ significantly from concentrations measured during a period of low-fat intake.

Cholesterol↗

PubMed2004

Bioethical considerations in animal production.

The Western Coordinating Committee-204 (WCC-204) on animal bioethics is a multistate research committee that was formed through the cooperation of several university and government personnel having diverse backgrounds. The WCC-204 is pleased to provide this symposium to Poultry Science Association (PSA) members and invite their participation in the committee. Generic objectives of the committee include facilitation of dialogue to improve our understanding of complex ethical issues related to animal production and utilization by humans, to encourage research and educational programs in this area, and to create a means for critical analysis of the animal sciences professions. The basis for philosophical discussions and religious implications of bioethical discussions that create profound differences of opinion between people is discussed. The various and often underappreciated contributions of society to the structure of our current food production system, and society's approach to change (taking marketplace responsibility for demands vs. regulations), are briefly discussed. Several factors that may contribute to the creation of conflicts and misunderstandings are listed. Speakers will discuss the WCC-204 organization, the need to define where there is agreement between opposing entities, education of students and others through contemporary issues classes, and global issues related to animal well-being.

Agriculture↗