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At least 649 records · Page 36Linked to original sources
PubMed1986

[Toxicity of oxygen, free radicals and defense mechanisms].

Oxygen is essential for the life of aerobic organisms as the terminal acceptor of electrons. Due to its high affinity for lone electrons it fosters radicular reactions and opposes recombinations of radicals after rupture of covalent linkages. Lipoperoxidation processes then occur, attacking the cellular membranes. These radicular reactions are at the origin of many pathological phenomena. A complex arsenal of endogenous protective agents is normally present in all cells to face up to the danger of lone electron structures in oxygenated media. Food and natural or synthetic pharmacological agents compensate for the deficiencies.

Aerobiosis↗
PubMedDate not supplied

Superparamagnetic particles as an MRI contrast agent for the gastrointestinal tract.

Non-biodegradable superparamagnetic particles containing magnetite were evaluated as a potential contrast agent for the gastrointestinal tract. The particles were administered to pigs perorally either suspended in water or mixed with food. The gastrointestinal tract structures were excellently depicted through a lowered signal intensity of their content in both T1 and T2 weighted images. Relatively large volumes with low particle concentration seemed to give a good contrast agent distribution, especially when the administration was extended over a period of time. Problems with artefacts and blurring in the images caused by a too high local concentration of the contrast agent should also be minimized by using low particle concentrations.

Animals↗
PubMed1979

An electron microscopic study of intra-erythrocytic stages of Babesia bovis in the brain capillaries of infected splenectomized calves.

Splenectomized vaccine donor calves undergoing primary reactions to Babesia bovis infections may develop cerebral babesiosis which leads to death if not treated in time. A brain biopsy was performed on an artificially-infected animal showing nervous symptoms and the tissue was immediately processed for electron microscopic examination. Virtually every erythrocyte in the brain capillaries sectioned was infected with B. bovis. Intra-erythrocytic merozoites, trophozoites and dividing trophozoites were indentified. Important features of the piriform merozoites included a reduced apical complex consisting of the anterior polar ring, microtubules, rhoptries and micronemes. Unidentified membrane-bound bodies, mostly spherical in shape, were observed anterior to the nucleus. The trophozoites showed very little structural differentiation and no food vacuoles or micropores could be detected. Each trophozoite produced 2 identical merozoites and the parent cell became totally incorporated in the daughter merozoites in the multiplication process. Projections were seen radiating from the surface of infected erythrocytes which appeared to adhere to other surfaces on contact. This probably resulted in the sludging of infected erythrocytes in the capillaries. The latter observations coincide with those described for Babesia argentina.

Animals↗
PubMedDate not supplied

[Effect of food with a high content of sunflower oil on the structure of vascular wall of rats on a low-protein diet].

It has been shown in experiments on rats fed a low-protein diet (5% according to the caloric value) that sunflower oil introduced into the diet in a high amount (50% according to the caloric value) does not exert any protective effect on the wall of the blood vessels (aorta, coronary and intrarenal arteries). The animals develop moderately marked morphological alterations similar to those seen in feeding a low-protein diet with high butter content. These alterations can be described as follows: the elastic fibers of the intima and media lose the tinctorial properties and elasticity; they swell and branch in some places; the destruction sites demonstrate the clusters of neutral and acid mucopolysaccharides.

Animals↗
PubMedDate not supplied

[Changes in lipid metabolic indices in children with chronic kidney diseases under the influence of diet therapy].

Variations in lipid metabolism were studied in 20 children with chronic glomerulonephritis (CGN) associated with the nephrotic syndrome and 14 children with chronic renal insufficiency given protein deficient therapeutic diets. Suggestive abnormalities of lipid metabolism involved hyperlipidemia, hypercholesterinemia and hypertriglyceridemia (more sharply pronounced in patients with CGN associated with the nephrotic syndrome) as well as hyperlipoproteidemia, chiefly of types IY and IIB. Disproportions in lipoproteid spectra of the plasma towards increase in atherogenous beta- and pre-beta-lipoproteids are characteristic for patients of both groups but sharply pronounced in CRI. These patients also show a reduced metabolization efficacy coefficient (MEC) of essential fatty acids of food to the lipid structures of erythrocyte membranes. As a results of the treatment the lipid metabolism returned to normal in most patients with CGN and in part of the patients with CRI. In order to raise the efficacy of therapeutic diets during normalization of lipid metabolism in CRI it is recommended that the fat and carbohydrate components of the diet may be changed qualitatively with due regard for the types of hyperlipoproteidemia.

Child↗
PubMed1996

[An outline of chloro-organic compound toxicology].

Chloroorganic compounds, typified by the chlorinated aliphatic and aromatic hydrocarbons, especially biphenyls, naphthalenes, dibenzo-p-dioxins, dibenzofuranes and azo/xy/benzenes are, or were, manufactured as commercial products /the chlorinated biphenyls and naphtalenes/, and occur only as contaminants in commercial products /the chlorinated dibenzo- p-dioxins, dibenzofurans, and azo/xy/benzenes/. They have all become widespread in the environment. The chemical stability and lipophilicity of these compounds, and their resistance to degradation results in their persistence in the environment and concentration in the food chains. Their chemical structures are similar, i.e. they are approximate isostereomers. They act by the common receptor-mediated mechanism and produce similar toxic responses, although they vary greatly in potency. All classes of chloroorganic compounds have produced incidents of intoxication of industrial workers, the general population, and farm or wild animals. Chlorinated aromatic hydrocarbons elicit a numerous toxic effects which include body weight loss, thymic atrophy, immunotoxicity, hepatotoxicity and porphyria, chloracne and another dermal lesions, tissue-specific hypo- and hyperplastic responses, teratogenicity, reproductive toxicity, and carcinogenesis.

Animals↗
PubMedDate not supplied

[Effect of the quality characteristics of the fatty component of the diet on the fatty acid makeup of the erythrocytic and thrombocytic membranes in healthy persons].

Practically healthy males received rations in which principal sources of fat in the descending order were butter, sunflower and mustard oil. The influence of qualitative properties of the ration's fat on the lipids metabolism in the plasma and the coefficient of the metabolization effectiveness of essential fatty acids (CEM) of the food into the membranes lipids was studied. The CEM was calculated by studying the fatty acids composition of the erythrocytes and thrombocytes stroma. Inclusion in the ration of butter alone, raised the cholesterol level, a fall of the plasma phospholipids level and a significant drop of the CEM. Substitution of sunflower oil for butter led to normalization of these figures. Mustard oil had no effect. Changes in the CEM of the erythrocytes stroma proceeded slowly, significant differences having been discovered only after 6 weeks of the butter consumption. The thrombocytes CEM changed quickly, a stable fatty acids composition of thrombocytes with this ration being established by the end of the 2nd week. The qualitative properties of the ration's fat exercise a sufficiently strong influence on the effective metabolization of fatty acids in the food into the lipid structures of the erythrocytes and thrombocytes membranes in a healthy subject, it being characterized by the CEM changes.

Adult↗
PubMed2003

[Allergies associated with both food and pollen].

Recent progress in understanding structural relationships between allergens has allowed their classification into molecular families. Proteins belonging to a molecular family often show some degree of IgE cross-reactivity. These cross-reactions can lead to a clinical association like birch-apple syndrome whose basis is a sensitization to a PR-10 protein (birch pollen Bet v 1) and then oral symptoms in contact to apple Mal d 1, another PR-10 family member. Food allergens implicated into pollen-food allergy syndromes differ from those linked to crustacea or milk cross-allergies: they seem unable to sensitize the patient through oral route. As a result, they most often induce weaker clinical reactions than complete allergens like those present in shrimp or cow milk. Numerous molecular families have been isolated from pollens. PR-10 and profilins have a well established role in inducing clinical reactions to food like fruits and vegetables. Some molecular families need more studies to delineate their true impact on pollen-driven food reactions: polygalacturonases, pectate lyases, isoflavone reductases, thaumatin-like, cyclophilins.... Others are found in pollen but not in eaten products: 2-EF-hand calcium binding proteins, beta expansins,... Lipid transfer proteins (LTP) are widespread plant food allergens (e.g. in peach): these proteins seem able to directly sensitize the patient through oral route. But recent data have suggested a possible additional effect of some LTP present in pollens (mugwort, olive, pellitory).

Allergens↗
PubMed1985

The time-structure of the anorectic effect of satietin.

The influence of anorectic doses of satietin, calcitonin, fenfluramine and amphetamine on the amount of food eaten, on the time elapsed before taking the first tablet (latency) and on the time-structure of food intake during a one hour feeding session, divided into four 15-minute periods, was measured in rats after one day starvation with a pellet-detecting eatometer. In contrast to fenfluramine, amphetamine significantly increased the time elapsed before taking the first tablet, indicating the stimulation of a satiety mechanism by fenfluramine and the inhibition of a feeding mechanism by amphetamine. In this test satietin and calcitonin acted like fenfluramine. The time-course of food intake was significantly different in the amphetamine and fenfluramine-treated animals, the latter ate more during the first 15-minute period. Satietin and calcitonin acted like fenfluramine in this test, too. The results are consistent with the view that satietin acts by activating a satiety mechanism.

Amphetamine↗
PubMed2005

A framework for measuring costs to society of IgE-mediated food allergy.

Both immunoglobulin E (IgE)-mediated food allergy and food intolerance can lead to many changes in personal behaviour and health care resource use which have important economic consequences. These costs will impact directly, indirectly and intangibly on both individuals and society in general. It is important to measure the cost of illness (COI) of food allergy as a first step in developing and evaluating measures to reduce and control the burden of illness. This paper outlines a framework for assessing COI of food allergy from different viewpoints. It offers a structure for identifying the different cost impacts on allergic and nonallergic consumers, food producers and society as a whole, and for scoping, measurement and valuation of relevant costs. Within this structure, the existing literature is reviewed. This review illustrates the lack of information and clear methodology for assessing costs of food allergy. The paper concludes that there is a need for a more structured research programme to generate data essential for future evaluations of procedures and technologies for the diagnosis, treatment and management of food allergy.

Cost of Illness↗
PubMed1996

Spontaneous use of matching visual cues during foraging by long-tailed macaques (Macaca fascicularis).

A social group of 38 captive-born Macaca fascicularis was confined to a holding cage while food was placed in an outdoor enclosure next to a structure (e.g., stone, tree) that varied across trials. After the group was released and obtained the food, animals inspected other structures similar to the baited structure more quickly and more often than they inspected equally conspicuous nonmatching structures. Animals also varied their search according to the quality of food, remembered the exact location of food on the previous trial, and discriminated sharply between locations where other macaques found or did not find food. Use of visual cues by experimentally naive macaques seems far more efficient than would be expected from many prior laboratory studies but is consistent with wild macaque foraging behavior.

Animals↗
PubMed2004

Timed hypocaloric food restriction alters the synthesis and expression of vasopressin and vasoactive intestinal peptide in the suprachiasmatic nucleus.

In mammals, the main circadian pacemaker is located in the suprachiasmatic nucleus (SCN) and its most potent synchronizer is the daily variation of the intensity of light. However, other nonphotic cues, such as timed food restriction, can induce changes in the circadian rhythms, leading also to the appearance of a food-entrained oscillator. The present study was designed to establish if the alterations of the circadian rhythms induced by timed hypocaloric food restriction are accompanied by structural changes in the SCN. Two groups of adult rats, both maintained on 12-h light/12-h dark cycles, were used; in one group, animals had permanent free access to food, whereas in the other they were subjected to a restricted hypocaloric early morning feeding during 7 months. Using stereological techniques and in situ hybridization, we have examined the structure of the SCN and the synthesis and expression of vasopressin (AVP) and vasoactive intestinal peptide (VIP). The volume of the SCN and the total number of neurons did not vary between the two groups. However, the total number of AVP- and VIP-immunoreactive neurons and the AVP and VIP mRNA levels were significantly decreased in timed hypocaloric food-restricted animals. The results indicate that timed hypocaloric food restriction has led to changes of AVP and VIP content of the neurons. They furthermore suggest the existence of a coupling between the food-entrainable oscillator and the light-entrainable pacemaker.

Animals↗
PubMed2005

Metabolite analysis in positron emission tomography studies: examples from food sciences.

Substances of various chemical structures can be labelled with appropriate positron emitting isotopes and applied as tracer compounds in PET examinations. Using dynamic data acquisition protocols, time-activity curves of radioactivity uptake in organs can be derived and the measurements of tissue tracer concentrations can be translated into quantitative values of tissue function. However, analysis of metabolites of these tracers regarding their nature and distribution in the living organism is an essential need for the quantitative analysis of PET measurements. In addition, metabolite analysis contributes to the interpretation of the images obtained as well as to the identification of pathological changes in metabolic pathways. This paper reports on representative examples of radiolabelled compounds which might be of importance in food science (e.g., amino acids, polyphenols, and model compounds for advanced glycation end products (AGEs)). Typical procedures of analysis (radio-HPLC, radio-TLC) including pre-analytical sample preparation are described. Specific challenges of the method, e.g., trace amounts of radiolabelled compounds and the influence of the often very short half-lives of positron-emitting nuclides used are highlighted. Representative results of analyses of plasma, urine, and tissue samples are presented and discussed in terms of the metabolic fate of the tracers.

Amino Acids↗
PubMed1996

IgE binding to a new cross-reactive structure: a 35 kDa protein in birch pollen, exotic fruit and other plant foods.

Food allergies in birch pollen allergic patients have been shown to be due to cross-reactivities of specific IgE antibodies which are directed against birch pollen allergens with related proteins in fruit, nuts and vegetables. We identified a new cross-reactive structure of 35 kDa in birch pollen and some plant food extracts by Enzyme Allergosorbent Test (EAST) and immunoblot inhibition studies. The 35 kDa birch pollen protein is a minor allergen to which approximately 10-15% of birch pollen allergic individuals have specific IgE. Our data demonstrate that there is cross-reactivity of this protein with proteins of comparable size from lychee, mango, banana, orange, apple, pear and carrot. While the 35 kDa protein is immunologically independent of the major birch pollen allergen Bet v 1, we also observed IgE binding to a 34 kDa structure which appears to be a Bet v 1 dimer.

Adult↗
PubMed1996

Comparison of aquatic food chains using nitrogen isotopes.

Recent studies have shown the utility of delta(15)N to model trophic structure and contaminant bioaccumulation in aquatic food webs. However, cross-system comparisons in delta(15)N can be complicated by differences in delta(15)N at the base of the food chain. Such baseline variation in delta(15)N is difficult to resolve using plankton because of the large temporal variability in the delta(15)N of small organisms that have fast nitrogen turnover. Comparisons using large primary consumers, which have stable tissue isotopic signatures because of their slower nitrogen turnover, show that delta(15)N increases markedly with the human population density in the lake watershed. This shift in delta(15)N likely reflects the high delta(15)N of human sewage. Correcting for this baseline variation in delta(15)N, we report that, contrary to expectations based on previous food-web analysis, the food chains leading up to fish varied by about only one trophic level among the 40 lakes studied. Our results also suggest that the delta(15)N signatures of nitrogen at the base of the food chain will provide a useful tool in the assessment of anthropogenic nutrient inputs.

Animals↗
PubMed1975

Action of gastrin on gastrointestinal structure and function.

In previous communications we have reported using the rat fed by total parenteral nutrition to examine the effects of the absence of food from the gut on functional and structural parameters of the gastrointestinal tract. In the current study three groups of animals were fed parenterally; one received a continuous infusion of pentagastrin equal to about one-half the D50 for acid secretion, another received a comparable infusion of histamine, and a third group was given only the liquid diet. These animals were compared to orally fed sham operated controls. The parenterally fed animals had significantly lower levels of antral and serum gastrin. When compared to whole body weight, the weights of the oxyntic gland area of the stomach, the pancreas, and the small intestine were significantly lower. In addition, the total and specific activities of the disaccharidase enzymes were significantly reduced. Pentagastrin prevented both the decreases in weights of the gastrointestinal tissues and the decreases in dissaccharidase activity. Histamine was without effect. We conclude that pentagastrin prevents the changes in gastrointestinal structure and function caused by the absence of food from the gut and that the trophic action of gastrin is necessary for the maintenance of the functional and structural integrity of the gastrointestinal tract.

Animals↗