bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of exercise and protein–energy supplements on body composition and muscle function in frail elderly individuals: a long-term controlled randomised study
Authors: Bonnefoy M. , Cornu C. , Normand S. , Boutitie F. , Bugnard F. , Rahmani A. , Lacour J. R. , Laville M.
Published: May 2003

Fighting against inactivity and inadequate nutritional intake are of utmost importance in the elderly. To our knowledge, the few studies which have been performed were conducted for only a short period and the results do not permit formal conclusions to be drawn. We therefore tried to fill this gap in our knowledge by determining whether an intervention combining an acceptable progressive exercise programme and nutritional supplements would be feasible for a long-term period in the very frail elderly, and would bring about concomitant benefits in body composition and muscle power. Accordingly, this exercise and nutritional combination was assessed in the frail elderly in a 9-month randomised trial with a factorial design. Fifty-seven elderly volunteers over 72 years, from sixteen retirement homes in Lyon, France participated in the study. Dietary supplements were compared with placebo, and physical exercise was compared with memory training. Main outcome measures were fat-free mass (FFM) and muscle power. FFM was determined by labelled water, and muscle power was measured by a leg-extensor machine. At 9 months, the compliance was 63 % for exercise sessions, and 54 % for nutritional supplements. In patients with dietary supplements, muscle power increased by 57 % at 3 months (P=0·03), and showed only a tendency at 9 months; although FFM increased by 2·7 % at 9 months, the difference was not significant (P=0·10). Exercise did not improve muscle power at 9 months, but improved functional tests (five-time-chair rise,P=0·01). BMI increased with supplements (+3·65 %), but decreased with placebo (−0·5 %) at 9 months (P=0·007). A long-term combined intervention is feasible in frail elderly individuals with a good rate of compliance. Nutritional supplements and exercise may improve muscle function. Despite no significant results on FFM, due to the limited number of volunteers, combined intervention should be suggested to counteract muscle weakness in the frail elderly.
Vitamin D in preventive medicine: are we ignoring the evidence?
Authors: Zittermann Armin
Published: May 2003

Vitamin D is metabolised by a hepatic 25-hydroxylase into 25-hydroxyvitamin D (25(OH)D) and by a renal 1α-hydroxylase into the vitamin D hormone calcitriol. Calcitriol receptors are present in more than thirty different tissues. Apart from the kidney, several tissues also possess the enzyme 1α-hydroxylase, which is able to use circulating 25(OH)D as a substrate. Serum levels of 25(OH)D are the best indicator to assess vitamin D deficiency, insufficiency, hypovitaminosis, adequacy, and toxicity. European children and young adults often have circulating 25(OH)D levels in the insufficiency range during wintertime. Elderly subjects have mean 25(OH)D levels in the insufficiency range throughout the year. In institutionalized subjects 25(OH)D levels are often in the deficiency range. There is now general agreement that a low vitamin D status is involved in the pathogenesis of osteoporosis. Moreover, vitamin D insufficiency can lead to a disturbed muscle function. Epidemiological data also indicate a low vitamin D status in tuberculosis, rheumatoid arthritis, multiple sclerosis, inflammatory bowel diseases, hypertension, and specific types of cancer. Some intervention trials have demonstrated that supplementation with vitamin D or its metabolites is able: (i) to reduce blood pressure in hypertensive patients; (ii) to improve blood glucose levels in diabetics; (iii) to improve symptoms of rheumatoid arthritis and multiple sclerosis. The oral dose necessary to achieve adequate serum 25(OH)D levels is probably much higher than the current recommendations of 5–15 μg/d.
Effect of smoking on erythorbic acid pharmacokinetics
Authors: Lykkesfeldt Jens , Bolbjerg Monica L. , Poulsen Henrik E.
Published: May 2003

Considerable evidence exists that smoking significantly lowers the concentration of plasma antioxidants. While for most antioxidants this effect appears to result mainly from altered dietary habits, ascorbic acid has recently been shown to be depleted by smoking per se. However, the direct cause of ascorbate depletion remains unclear. Erythorbic acid is a stereoisomer of ascorbic acid commonly used as antioxidant in foodstuffs and has the same redox properties as ascorbic acid. We therefore investigated if erythorbic acid could be used as a non-isotopic marker of smoking-induced oxidative stress. In a sample of smokers (n 10) and non-smokers (n 10), the pharmacokinetics of erythorbic acid were followed after a single oral dose (1 g) and subsequently, the effect of a 2-week ascorbic acid supplementation (0·5 g/d) on erythorbic acid kinetics was studied in a double-blind, placebo-controlled fashion. There were no significant effects of smoking or supplementation on relative bioavailability (difference in area under curve, AUC0-∞) of erythorbic acid (smokers 357 (SD 119), non-smokers 414 (SD 142) μmol·h/l; P=0·34). Time to reach maximum plasma concentration (Tmax) was significantly less in smokers (P=0·03). If the relative pharmacokinetics of erythorbic acid between smokers and non-smokers compares with those of AA, our present results do not suggest that altered pharmacokinetics is likely to play a major role in the ascorbic acid depletion consistently observed in smokers.
Effect of 4-coumaric and 3,4-dihydroxybenzoic acid on oxidative DNA damage in rat colonic mucosa
Authors: Guglielmi Francesco , Luceri Cristina , Giovannelli Lisa , Dolara Piero , Lodovici Maura
Published: May 2003

The effect of 4-coumaric and 3,4-dihydroxybenzoic (protocatechuic) acid on the basal oxidative DNA damage of rat colonic mucosa in vivo was studied, relative to vitamin E. F344 rats were treated with 4-coumaric or protocatechuic acid mixed in the diet (25 or 50 mg/kg for 2 weeks). It was observed that 4-coumaric acid (50 mg/kg) significantly decreased the basal level of the oxidative damage assessed as 8-OH-2′-deoxyguanosine levels in DNA and by the comet assay. Moreover, it was found that vitamin E (10 mg/kg) had no effect on colonic mucosa oxidation damage, whereas at a higher dose (55 mg/kg) it actually enhanced oxidative stress. The effect of 4-coumaric acid (50 mg/kg) on the expression of some glutathione-related enzymes (glutathione-S-transferase (GST)-P, GST-M2, GST-M1, γ-glutamylcysteine synthetase, glutathione peroxidase (GSPX)1 and GSPX4) was also investigated at the level of the colonic mucosa. Only the expression of GST-M2 was significantly induced by 4-coumaric acid, while protocatechuic acid was inactive. The data suggest that 4-coumaric acid acts as an antioxidant in the colonic mucosa in vivo.
The occurrence and infection dynamics of Anisakis larvae in the black-scabbard fish, Aphanopus carbo, chub mackerel, Scomber japonicus, and oceanic horse mackerel, Trachurus picturatus from Madeira, Portugal
Authors: Costa G. , Pontes T. , Mattiucci S. , D'Amélio S.
Published: May 2003

Larval stages of Anisakis spp. (Nematoda: Anisakidae) were found encapsulated or free in the viscera and abdominal cavity of the black-scabbard fish, Aphanopus carbo, chub mackerel, Scomber japonicus and oceanic horse mackerel, Trachurus picturatus in Madeiran waters. The prevalence of infection reached 97.2% (n=142) for A. carbo, 69.5% (n=154) for S. japonicus and 62.5% (n=40) for T. picturatus. Considerable differences in parasite intensities between A. carbo and both S. japonicus and T. picturatus were found, with mean intensities up to 69.6 in A. carbo, while in the other two fish hosts the intensity reached only a maximum of 2.6. These differences were probably due to different feeding behaviours of the hosts. Intensities of Anisakis sp. in A. carbo were high irrespective of sex and season. No relationship between host length and prevalence of infection was observed for A. carbo, while for S. japonicus a weak positive significant relationship was found.
Potential interactions between metazoan parasites of the Mayan catfish Ariopsis assimilis and chemical pollution in Chetumal Bay, Mexico
Authors: Vidal-Martínez V.M. , Aguirre-Macedo M.L. , Noreña-Barroso E. , Gold-Bouchot G. , Caballero-Pinzón P.I.
Published: May 2003

The effect of pollutants on the intensity of infection of metazoan parasites in the Mayan catfish, Ariopsis assimilis was investigated. Data were collected on pollutants and metazoan parasites from 76 catfish from five localities in Chetumal Bay in October, 1996. Nineteen pollutants (pesticides, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs)) were found in the catfish livers. Heavy metal content was not determined. Nineteen metazoan parasite species were recovered. After controlling for fish length and sampling station, there was a significant negative linear relationship between the intensity of the larval digenean Mesostephanus appendiculatoides and 1,1,1,-trichloro-2,2-bis (4-chlorophenyl) ethane (DDT) concentrations. This negative relationship may be explained either by the effect of the pesticide on the mortality of (i) free-living larval forms, (ii) metacercariae in the fish, (iii) infected fish or (iv) intermediate host snails. There were significant differences between fish parasitized and not parasitized with M. appendiculatoides with respect to their DDT concentrations. There were also significant differences between the variances of the mean Clark's coefficient of condition values between catfish parasitized and not parasitized by M. appendiculatoides, with the variance of non-parasitized catfish being significantly larger. The results provided statistical evidence that DDT has a detrimental effect on M. appendiculatoides infection intensity. Furthermore, the significantly larger variance value of Clark's coefficient for non-parasitized fish suggested that DDT affects both the parasite and general host condition.
Immunity to Trichuris muris in the laboratory mouse
Authors: Else K.J. , deSchoolmeester M.L.
Published: May 2003

Of all the laboratory models of intestinal nematode infection, Trichuris muris in the mouse is arguably the most powerful. This is largely due to the fact that the ability to expel this parasite is strain dependent. Thus, most mouse strains readily expel T. muris. However certain mouse strains, and indeed some individuals within particular mouse strains, are unable to mount a protective immune response and harbour long term chronic infections. This unique model thus presents an opportunity to examine the immune events underlying both resistance to infection and persistent infection within the same host species, and in some cases, the same host strain.
Biological variation in Trichinella species and genotypes
Authors: Bolas-Fernández F.
Published: May 2003

At present, the genus Trichinella comprises seven species of which five have encapsulated muscle larvae (T. spiralis, T. nativa, T. britovi, T. nelsoni and T. murrelli) and two do not (T. pseudospiralis and T. papuae) plus three genotypes of non-specific status (T6, T8 and T9). The diagnostic characteristics of these species are based on biological, biochemical and genetic criteria. Of biological significance is variation observed among species and isolates in parameters such as infectivity and immunogenicity. Infectivity of Trichinella species or isolates is determined, among other considerations, by the immune status of the host in response to species- or isolate-specific antigens. Common and particular antigens determine the extent of protective responses against homologous or heterologous challenge. The kinetics of isotype, cytokine and inflammatory responses against T. spiralis infections are isolate-dependent. Trichinella spiralis and T. pseudospiralis induce different dose-dependent T-cell polarizations in the early host response, with T. spiralis initially preferentially promoting Th1-type responses before switching to Th2 and T. pseudospiralis driving Th2-type responses from the outset.
Host–parasite interactions in rodent nematode infections
Authors: Mahida Y.R.
Published: May 2003

In rodents, Trichinella spiralis and Nippostrongylus brasiliensis infect the small intestine and Trichuris muris resides in the colon. The intestinal host response in these animals is characterized by changes in mucosal architecture and inflammation and is associated with worm expulsion. The requirement of T cell-mediated host response in worm expulsion has been demonstrated over many years. Subsequent studies have shown that Th2-type, but not Th1-type, responses mediate resistance to the nematodes. Investigations using neutralizing antibodies and genetically manipulated mice have characterized the contribution of individual Th2-type cytokines in not only worm expulsion, but also specific cellular changes that occur in the mucosa, such as alterations in epithelial phenotype and smooth muscle. There is also increasing appreciation of the contribution of non-bone marrow-derived cells in innate and adaptive host responses in these models.
The relative involvement of Th1 and Th2 associated immune responses in the expulsion of a primary infection of Heligmosomoides polygyrus in mice of differing response phenotype
Authors: Ben-Smith A. , Lammas D.A. , Behnke J.M.
Published: May 2003

T helper cell (Th1 and Th2) associated responses were examined following a primary infection with the gastrointestinal nematode Heligmosomoides polygyrus in five inbred strains of mice with different resistance phenotypes. Levels of (i) mast cell protease, (ii) specific IgE, (iii) nitric oxide and (iv) specific IgG2a, as markers of Th2 and Th1 associated responses, respectively, were determined in sera and intestinal fluids and correlated with worm burdens. The ‘fast’ responder (resistant) strains SWR and SJL produced strong Th2 and Th1 associated responses respectively in a mutually exclusive fashion. The F1 hybrid (SWR×SJL) F1, showed rapid expulsion of the parasite and expressed both intense Th1 and Th2 responses, suggesting synergism between Th1 and Th2 activity in these mice. The results indicate that both Th2 and Th1 responses operate in mice following a primary infection with H. polygyrus and that each Th response may be involved to a greater or lesser degree within certain strains. Resistance to H. polygyrus was found to correlate only to the intensity of either the gut-associated mastocytosis or nitric oxide production in these strains but not to either specific IgE or IgG2a titres. Chronic infections in the ‘slow’ response phenotype mouse strains CBA and C57BL/10, were associated with both poor Th2 and poor Th1-associated responses attributed to a general parasite-mediated immunosuppression of the host immune response to infection.
Responses of inbred mouse strains to infection with intestinal nematodes
Authors: Dehlawi M.S. , Goyal P.K.
Published: May 2003

Comparisons were made of the immune and inflammatory responses of four strains of inbred mice to infection with the intestinal nematodes Trichinella spiralis and Nippostrongylus brasiliensis to determine whether genetically determined ‘high responsiveness’ to infection, seen most clearly in intestinal responses, is independent of the parasite concerned and necessarily correlated with protection. The time course of infection was followed by counting adult worms at intervals after infection. Mucosal mast cells and Paneth cell numbers were determined as indices of the intestinal inflammatory response. Levels of IgG2a and IgG1 antibodies and of the cytokines IFN-γ and IL-5 released from in vitro-stimulated mesenteric node lymphocytes were measured to assess type 1 and type 2 responses. NIH and CBA mice were the most resistant to T. spiralis and N. brasiliensis respectively, resistance in each case being correlated with the most intense intestinal inflammatory responses. C57BL/10 (B10) and B10.BR were the least resistant to T. spiralis, but were as resistant as CBA to N. brasiliensis, despite their intestinal inflammatory responses to both parasites being much lower than the other two strains. Mice infected with T. spiralis made the expected switch from a type 1 (IFN-γ) to a type 2 (IL-5) response between days 2 and 8, and there were no significant differences in levels of these cytokines between the strains. In contrast, when infected with N. brasiliensis, CBA showed an IFN-γ response at day 4, all strains switching to IL-5 by day 8 and NIH mice releasing the greatest amount of IL-5. The results indicate that the ‘high responder’ phenotype to intestinal nematode infection is in part determined by host characteristics, but is also determined by the parasite concerned – seen most clearly by the differences between NIH and CBA when infected with T. spiralis and N. brasiliensis. The fact that ‘low responder’ B10 background mice were more resistant to N. brasiliensis than ‘high responder’ NIH implies that each parasite elicits a particular pattern of protective host responses, rather than parasites being differentially susceptible to the same response profile.
Causality or coincidence: may the slow disappearance of helminths be responsible for the imbalances in immune control mechanisms?
Authors: Palmas C. , Gabriele F. , Conchedda M. , Bortoletti G. , Ecca A.R.
Published: May 2003

Intestinal infection continues to be a problem worldwide and helminths, which currently infect billions of individuals, are primary culprits. The major burden of disease falls on the populations of developing countries, given that over the last four to five decades helminth infections are disappearing in industrialized societies. In developing countries, a major source of immunomodulatory signals in post-natal life are parasites, particularly helminths, which, unlike most bacteria and viruses, selectively stimulate Th2 function. Helminths and their eggs are probably the most potent stimulators of mucosal Th2 responses. Responses elicited by worms can modulate immune reactions to other parasites, bacterial, viral infections and several unrelated diseases. Bacterial and protozoal infections may also protect against atopy and asthma, through the induction of the Th1 regulatory responses. Today, people in developed countries often live in ultra-hygienic environments, avoiding exposure to viruses, bacteria, ectoparasites and endoparasites, particularly helminths. Perhaps failure to acquire worms and experience mucosal Th2 conditioning predisposes to unrelated diseases. In contrast to this hypothesis it has also been suggested that Th2 responses can make the host more susceptible to other important diseases and to contribute to the spread of them.
Fibre and water binding
Authors: Chaplin Martin F.
Published: May 2003

The range of interactions between fibre and water and the consequential properties of the bound water are modelled and examined. Dietary fibre may interact with water by means of polar and hydrophobic interactions, hydrogen bonding and enclosure. The results of these interactions vary with the flexibility of the fibre surface. When the fibre is insoluble or junction zones are formed, this may result in profound changes in the surrounding water. Such interactions are capable of affecting the structuring and solvation properties of water well away from the immediate surfaces involved. In particular, the specific properties of water enclosed by dietary fibre are examined, an area of investigation previously receiving scant attention. The way this enclosure may affect the properties of water is exemplified by modelling the colon to show how fibre may exert a beneficial action by the preferential partitioning of hydrophobic carcinogens. Unfermented dietary fibre has a tendency to form low-density expanded water that acts as a preferential solvent for hydrophobic molecules when compared with the less-structured denser water within the much more hydrophilic mucus layer.
Influences of probiotic bacteria on organic acid production by pig caecal bacteriain vitro
Authors: Sakata Takashi , Kojima Taichi , Fujieda Masatoshi , Takahashi Masanori , Michibata Takashi
Published: May 2003

The mechanism of action of probiotics is largely unknown. A potential mechanism should be to increase the production of short-chain fatty acids (SCFA), known modulators of gut functions, by the bacterial ecosystem in the large intestine. The present paper reviews our recent studies in which the capacity of probiotic bacteria to increase the production of SCFA by pig caecal bacteria was investigated using batch-culture and continuous-culture techniques. All four commercial probiotic preparations and three strains of probiotic bacteria dose-dependently accelerated the net production of SCFA, succinic acid and lactic acid without changing the acid profile, and slowed the net production of NH4. Effects on organic acid production did not vary among different probiotic species. Neither probiotic preparations nor probiotic bacteria affected the organic acid production from glucose, gastric mucin, starch or lactose, or organic acids produced:added saccharide. Glucose abolished these effects of probiotic preparations. However, the capacity of probiotics to increase SCFA production was not modified by gastric mucin, starch or lactose. These results indicate that probiotic bacteria increase SCFA production by accelerating the breakdown of carbohydrates that are resistant to indigenous bacteria, and suggest that the concept of prebiotics in terms of SCFA production as a measure of probiotic function is arguable.
Molecular weight, tertiary structure, water binding and colon behaviour of ispaghula husk fibre
Authors: Al-Assaf Saphwan , Phillips Glyn O. , Williams Peter A. , Takigami Shoji , Dettmar Peter , Havler Michael
Published: May 2003

Molecular variables, using aqueous and alkaline extracts, of the polysaccharide from ispaghula husk (IH) were examined using gel-permeation chromatography linked to multi-angle laser light scattering. Progressive extraction can yield a component with a molecular weight (MW) value up to about 7×106 Da, and gels, which accompany the extraction, have MW ranging from 10–20× 106 Da. To mimic the polysaccharide degradation, particularly in the colon, the solid IH was degraded progressively using ionising radiation. A chain break occurs every 7.5 kGy in NaOH and every 15 kGy in water. The solid-state matrix is opened by the radiation to yield increased visco-elasticity of the aqueous extracts at critical radiation doses, before further degradation occurs after about 12 kGy. Differential scanning calorimetry is used to study the mechanism of interaction of water with IH. The first water to be taken up is non-freezing water and represents about twelve water molecules/disaccharide unit of the polysaccharide. As the water content is increased, the water becomes bound to the polysaccharide and freezes and melts at a temperature different from free water. This water is thermodynamically distinguishable from free water. It forms amorphous ice on cooling which crystallises exothermically and subsequently melts endothermically. Saturation occurs at a water content of 2–3 g water/g polymer, showing that about 60% of the water in the system is ‘bound’. The most surprising conclusion is that despite the fact that the IH swells in water to form a solid and stiff gel, the greater part of that water in the gel is still free and behaves like liquid water.
Why whole grains are protective: biological mechanisms
Authors: Slavin Joanne
Published: May 2003

Epidemiological studies find that whole-grain intake is protective against cancer, cardiovascular disease, diabetes and obesity. Potential mechanisms for this protection are diverse since whole grains are rich in nutrients and phytochemicals. First, whole grains are concentrated sources of dietary fibre, resistant starch and oligosaccharides, carbohydrates that escape digestion in the small intestine and are fermented in the gut, producing short-chain fatty acids (SCFA). SCFA lower colonic pH, serve as an energy source for the colonocytes and may alter blood lipids. These improvements in the gut environment may provide immune protection beyond the gut. Second, whole grains are rich in antioxidants, including trace minerals and phenolic compounds, and these compounds have been linked to disease prevention. Additionally, whole grains mediate insulin and glucose responses. Although lower glycaemic load and glycaemic index have been linked to diabetes and obesity, risk of cancers such as colon and breast cancer have also been linked to high intake of readily-available carbohydrate. Finally, whole grains contain many other compounds that may protect against chronic disease. These compunds include phytate, phyto-oestrogens such as lignan, plant stanols and sterols, and vitamins and minerals. As a consequence of the traditional models of conducting nutrition studies on isolated nutrients, few studies exist on the biological effects of increased whole-grain intake. The few whole-grain feeding studies that are available show improvements in biomarkers with whole-grain consumption, such as weight loss, blood lipid improvement and antioxidant protection.
Oligosaccharides: state of the art
Authors: Delzenne N. M.
Published: May 2003

Oligosaccharides, consisting of a mixture of hexose oligomers with a variable extent of polymerisation, are food products with interesting nutritional properties. They may be naturally present in food, mostly in fruits, vegetables or grains, or produced by biosynthesis from natural sugars or polysaccharides and added to food products because of their nutritional properties or organoleptic characteristics. The dietary intake of oligosaccharides is difficult to estimate, but it may reach 3–13 g/d per person (for fructo-oligosaccharides), depending on the population. The extent of resistance to enzymic reactions occurring in the upper part of the gastrointestinal tract allows oligosaccharides to become ‘colonic nutrients’, as some intestinal bacterial species express specific hydrolases and are able to convert oligosaccharides into short-chain fatty acids (acetate, lactate, propionate, butyrate) and/or gases by fermentation. Oligosaccharides that selectively promote some interesting bacterial species (e.g. lactobacilli, bifidobacteria), and thus equilibrate intestinal microflora, are now termed prebiotics. The pattern of short-chain fatty acid production in the caeco-colon, as well as the prebiotic effect, if demonstrated, are dynamic processes that vary with the type of oligosaccharide (e.g. extent of polymerisation, nature of hexose moieties), the duration of the treatment, the initial composition of flora or the diet in which they are incorporated. Experimental data obtainedin vitroandin vivoin animals, and also recent data obtained in human subjects, support the involvement of dietary oligosaccharides in physiological processes in the different intestinal cell types (e.g. mucins production, cell division, immune cells function, ionic transport) and also outside the gastrointestinal tract (e.g. hormone production, lipid and carbohydrates metabolism). The present paper gives an overview of the future development of oligosaccharides, newly recognised as dietary fibre.
Importance of processing for physico-chemical and physiological properties of dietary fibre
Authors: Margareta E. , Nyman G.-L.
Published: May 2003

There is considerable loss of DM during wet heat treatment of vegetables, leading to an increase in dietary fibre. Correction for the loss of DM indicates that the effects on total dietary fibre are minor. There is, however, depolymerization of the dietary fibre polysaccharides. The degradation is related to the severity of the heat treatment. Souring, freezing and mild microwave treatment have no effects. The viscosity is in general related to the extent of polymerisation. Microwave treatment has different effects on various cultivars of green beans, and the addition of salt (NaCl and CaCl2) to the boiling water changes the physico-chemical properties of soluble fibre in carrots, depending on the cation. The higher viscosity of the soluble fibre in raw carrots may partly explain the lower glucose and hormonal responses observed in healthy subjects when compared with blanched and microwave-cooked carrots. In studies on rats the amount of butyric acid in the distal colon has been shown to be higher with dietary components containing high amounts of resistant starch. Further, the fermentability is lower and the butyric acid concentration higher with composite foods than with the corresponding purified fibre fractions. In human studies the faecal concentration of butyric acid has been shown to increase in patients with ulcerative colitis when β-glucan-enriched oat bran (20 g fibre) is added to the diet for 12 weeks. Also, an improvement of symptoms was reported.
Dietary fibre in infancy and childhood
Authors: Edwards C. A. , Parrett A. M.
Published: May 2003

There is very little evidence for the effects of dietary fibre in young children and current dietary guidelines are based on assumptions and data extrapolated from studies in adults. The first years of life may be critical for the establishment of a healthy colonic microflora, as well as good eating habits. The lack of clear and well-founded guidelines for the intake of dietary fibre in childhood may hinder both factors. The fears that a high-fibre diet in children <5 years of age will lead to growth faltering and mineral imbalance are not well supported in the literature, especially for children in the developed world. Indeed, with the rising levels of obesity, fibre intake may be of benefit in reducing energy intake. A low-fibre diet may also be implicated in the aetiology of childhood constipation and appendicitis. The latest proposals for the definition of dietary fibre include oligosaccharides, which may act as prebiotics. There are potential health benefits of including oligosaccharides in the diets of infants and children, but more research is needed to consider the long-term effects. The immature intestine of the infant may also result in a greater amount of starch entering the colon during weaning, and this starch would now be considered dietary fibre under the new definitions. Much new research is needed to allow adequate recommendations for the intake of dietary fibre in childhood based on data collected in appropriate age-groups.
Whole grain consumption and weight gain: a review of the epidemiological evidence, potential mechanisms and opportunities for future research
Authors: Pauline Koh-Banerjee , Rimm Eric B.
Published: May 2003

The epidemiological data that directly examine whole grainv. refined grain intake in relation to weight gain are sparse. However, recently reported studies offer insight into the potential role that whole grains may play in body-weight regulation due to the effects that the components of whole grains have on hormonal factors, satiety and satiation. In both clinical trials and observational studies the intake of whole-grain foods was inversely associated with plasma biomarkers of obesity, including insulin, C-peptide and leptin concentrations. Whole-grain foods tend to have low glycaemic index values, resulting in lower postprandial glucose responses and insulin demand. High insulin levels may promote obesity by altering adipose tissue physiology and by enhancing appetite. The fibre content of whole grains may also affect the secretion of gut hormones, independent of glycaemic response, that may act as satiety factors. Future studies may examine whether whole grain intake is directly related to body weight, and whether the associations are primarily driven by components of the grain, including dietary fibre, bran or germ.
Can resistant starch and/or aspirin prevent the development of coloi neoplasia? The Concerted Action Polyp Prevention (CAPP) 1 Study
Authors: Mathers John C. , Mickleburgh Ian , Chapman Pam C. , Bishop D. Tim , Burn John
Published: May 2003

Loss of function of the adenomatous polyposis coli (APC) tumour suppressor gene through truncating mutations or other means is an early event in most colo-rectal cancer (CRC). The AFC gene encodes a large multifunctional protein that plays key roles in several cellular processes, including the wnt signalling pathway where an intact APC protein is essential for down regulation of β-catenin. The APC protein also plays a role in regulation of cell proliferation, differentiation, apoptosis, cell-cell adhesion, cell migration and chromosomal stability during mitosis. Acquisition of a non-functional APC gene can occur by inheritance (in the disease familial adenomatous polyposis (FAP)) or by a sporadic event in a somatic cell. Whilst there is strong epidemiological evidence that variation in diet is a major determinant of variation in CRC incidence, conventional adenoma recurrence trials in sporadic cases of the disease have been relatively unsuccessful in identifying potentially protective food components. Since the genetic basis of CRC in FAP and in sporadic CRC is similar, intervention trials in FAP gene carriers provide an attractive strategy for investigation of potential chemo-preventive agents, since smaller numbers of subjects and shorter time frames are needed. The Concerted Action Polyp Prevention (CAPP) 1 Study is using a 2×2 factorial design to test the efficacy of resistant starch (30 g raw potato starch-Hylon VII (1:1, w/w)/d) and aspirin (600 mg/d) in suppressing colo-rectal adenoma formation in young subjects with FAP. Biopsies of macroscopically-normal rectal mucosa are also being collected for assay of putative biomarkers of CRC risk.
Primary structure of arabinoxylans of ispaghula husk and wheat bran.
Authors: Edwards Sandra , Chaplin Martin F. , Blackwood Anne D. , Dettmar Peter W.
Published: May 2003

he primary structures of ispaghula husk and wheat bran were investigated in order to determine how and why these fibres are among the most beneficial dietary fibres. To this end, the polysaccharide preparations have been subjected to enzymic hydrolysis and methylation analysis. The results have shown ispaghula husk and wheat bran to be very-highly-branched arabinoxylans consisting of linear Β-D-→l(4)-linked xylopyranose →Xylp) backbones to which a-L-arabinofuranose →Araf) units are attached as side residues via α-→1(3) and a-→l(2) linkages. Other substituents identified as present in wheat bran include Β-D-glucuronic acid attached via the C→O)-2 position, and arabinose oligomers, consisting of two or more arabinofuranosyl residues linked via 1–2, 1–3, and 1–4 linkages. Ispaghula-husk arabinoxylan is more complex having additional side residues which include a-D-glucuronopyranose →GalAp)-→l→2(-linked-α-L-rhamnopyranose-(1→4)-β-D-Xylp, α-D-GalA/>-→l→3(-linked-a-L-Araf-→1)4(-p-D-Xylp, and <x-L-Araf-→1→3(-linked-p-D-Xylp-→1→4(-β-D-Xylp. The beneficial effects of increased faecal bulk and water-holding capacity are undoubtedly related to the structures of the arabinoxylans, with differences in their efficacy to treat various functional bowel disorders due to their specific structural features
Whole grain health claims in the USA and other efforts to increase whole-grain consumption
Authors: Marquart Len , Wiemer Kathryn L. , Jones Julie M. , Jacob Brenda
Published: May 2003

In response to the 1990 Nutrition Labeling and Education Act, the Food and Drug Administration approved seven health claims that addressed the relationship between broad food categories and risk of certain chronic diseases. These claims are based on scientific consensus that includes epidemiological, animal and clinical research. The Food and Drug Administration also established a process to petition for new health claims that address substance-disease relationships supported by adequate scientific and specific regulatory requirements. The whole grain-cancer and heart disease authoritative statement health claim approved in July 1999 followed a completely different process mandated by the Food and Drug Administration Modernization Act of 1997. It is based on an authoritative statement made by a government body that represents scientific consensus and is supported by other scientific agencies and organizations. The scientific basis for the claim published inDiet and Healthreflects a comprehensive and deliberative review of epidemiological, animal and human studies by the National Academy of Sciences Committee on Diet and Health. Health claims used on whole-grain products can attract the attention of health-conscious consumers and are important tools in communicating health messages. However, the US public consumes substantially fewer whole-grain servings than recommended by US dietary guidance. Reasons given by consumers for not purchasing whole-grain foods include colour, price, softness, texture, moisture content and taste. Developing tastier value-added whole-grain foods along with simple coordinated messages from industry, the scientific community, public health experts and government will help consumers identify, purchase and consume more whole-grain products.
Are seed dormancy and persistence in soil related?
Authors: Thompson Ken , Ceriani Roberta M. , Bakker Jan P. , Bekker Renée M.
Published: May 2003

There is confusion in the ecological literature between seed dormancy and persistence in soil. Some ecologists seem to assume that dormancy is necessary for persistence, while others imply that dormancy and persistence are virtually synonymous. Here, we show that there is no close relationship between dormancy and persistence and, incidentally, that conventional methods of investigating soil seed banks underestimate the persistence of species with dormant seeds. The confusion appears to arise from the concept of ‘enforced dormancy’, which is not genuinely dormancy at all, and would be eliminated if ecologists adopted the definition of dormancy employed by physiologists. Dormancy is a characteristic of the seed, not of the environment, the degree of which defines the conditions required to make the seed germinate.
Comparisons of soil seed bank classification systems
Authors: Csontos Péter , Tamás Júlia
Published: May 2003

Since 1969, ten soil seed bank classification systems have been published. Among these systems, the number of recognized seed bank categories varies from three to twelve. Seed longevity is the main factor used for distinguishing categories, but dormancy and germination types are also important. Systems considering relatively few seed bank categories have been the most commonly proposed in contemporary plant ecology. In contrast, systems involving high numbers of categories have received limited interest because the detailed ecological knowledge of individual species required for their successful categorization is usually missing. A comprehensive table on the main features of seed bank classification systems is provided.
The cell cycle and seed germination
Authors: Vázquez-Ramos Jorge M. , de la Paz Sánchez María
Published: May 2003

The cell cycle is the series of molecular events that allows cells to duplicate and segregate their chromosomes to form new cells. The finding that a protein kinase, the product of the yeastcdc2gene, was fundamental in the regulation of the G2/M and G1/S transitions, associated with unstable proteins named cyclins, opened a very exciting and dynamic research area. The number of gene products that participate in the development and regulation of the cell cycle may be in the hundreds, and there is a high degree of conservation in protein sequences and regulatory pathways among eukaryotes. Although there are clear differences between plants and animals in cell structure, organization, growth, development and differentiation, the same types of proteins and very similar regulatory pathways seem to exist. Seed germination appears to be an excellent model system for studying the cell cycle in plants. Imbibition will reactivate meristematic cells – most initially with a G1DNA content – into the cell cycle in preparation for seedling establishment. Early events include a thorough survey of DNA status, since the drying process and seed storage conditions reduce chromosomal integrity. The initiation of cell cycle events leading to G1and S phases, and of the germination process itself, may depend on a G1checkpoint control. Most, if not all, cell cycle proteins appear to be already present in unimbibed embryos, although there is evidence of protein turnover in the early hours, suggesting the need forde novoprotein synthesis. Regulation also may occur at the level of protein modification, because existing G1, S and G2cell cycle proteins appear to be activated at precise times during germination. Thus, cell cycle control during seed germination may be exerted at multiple levels; however, knowledge of cell cycle events and their importance for germination is still scarce and fragmentary, and different species may have developed unique control mechanisms, more suited to specific germination characteristics and habitat.
Cell cycle and germination of fresh, dried and deteriorated sugarbeet seeds as indicators of optimal harvest time
Authors: Śliwińska Elwira
Published: May 2003

Seeds of sugar beet (Beta vulgarisL.) were collected at weekly intervals from 3 weeks before to 1 week after commercial harvest time, dried and stored at room temperature (18–22°C). Laboratory germination tests and flow cytometric analyses were performed immediately after harvest (fresh seeds) and five times at weekly intervals during storage (dry seeds). After 6 months of storage, seeds were exposed to a controlled deterioration treatment (CD). The proportion of G2nuclei in the embryo was constant in the fresh seeds, regardless of their maturity. It decreased, however, after drying and CD, especially in those seeds harvested before maturation drying had commenced. The proportion of endosperm cells in the seed decreased with maturation, and a further decrease was observed after drying and CD. These observations suggest that nuclei with a higher nuclear DNA content were more sensitive to water stress caused by premature desiccation and to deterioration than nuclei with a lower DNA content. Fresh seeds exhibited some germination, but this increased after drying, suggesting that desiccation induced a switch from the developmental to the germination mode. Germination percentages were the highest in dry seeds collected at the commercial harvest time and a week after. This high germinability coincided with the highest proportion of G2cells in the embryo. It is concluded that flow cytometry provides information about the status of sugarbeet seed maturation, seed quality and storage potential, and can be used for estimation of optimal harvest time.
Distinct expression patterns of β-1,3-glucanases and chitinases during the germination of Solanaceous seeds
Authors: Petruzzelli Luciana , Müller Kerstin , Hermann Katrin , Leubner-Metzger Gerhard
Published: May 2003

The expression patterns of β-1,3-glucanases (βGlu) and chitinases (Chn) were investigated during the seed germination of members of theCestroideae(threeNicotianaspecies,Petunia hybrida) and theSolanoideae(Capsicum annuum,Physalis peruviana) subgroups of Solanaceous species. Rupture of the micropylar testa (seed coat) and rupture of the micropylar endosperm, i.e. radicle emergence, were distinct and temporally separate events during the germination ofCestroideae-type seeds. βGlu accumulation in imbibedCestroideae-type seeds, occurring after testa rupture but prior to endosperm rupture, was inhibited by abscisic acid (ABA) and promoted by gibberellins (GA) and light, in strict association with germination, and appeared to be caused by transcriptional regulation of the class I βGlu genes. The micropylar cap ofSolanoideae-type seeds does not allow a distinction between testa and endosperm rupture, but βGlu accumulation occurred prior to radicle emergence of pepper andP. peruvianaseeds. ABA inhibited endosperm rupture and βGlu accumulation in the micropylar cap of pepper seeds. In contrast to tomato, βGlu accumulation in pepper seeds was not only confined to the micropylar cap, was due to distinct, tissue-specific βGlu isoforms, and was not accompanied by Chn accumulation. In conclusion, ABA inhibition of germination and βGlu accumulation in the micropylar endosperm appears to be a widespread event during the seed germination of Solanaceous species. In contrast, accumulation of Chn and distinct βGlu isoforms in the embryo, prior to germination, appears to be a species-specific phenomenon within theSolanaceae. In addition, a post-germination co-induction of βGlu and Chn in the root of the emerged seedling was found in endospermic and non-endospermic species and could represent an evolutionarily conserved event during dicot seedling development.
Acquisition of desiccation tolerance in developing oil palm (Elaeis guineensis Jacq.) embryos in planta and in vitro in relation to sugar content
Authors: Aberlenc-Bertossi Frédérique , Chabrillange Nathalie , Corbineau Françoise , Duval Yves
Published: May 2003

Relationships between desiccation tolerance and dry matter, water and sugar contents were studied throughout the development of oil palm (Elaeis guineensis Jacq.) zygotic embryos and in immature embryos cultured on a sucrose-enriched medium. Embryo dry weight during in planta development increased between 80 and 140 d after pollination (DAP) and was then stable until maturity. Embryos underwent dehydration until 120 DAP, but their moisture content remained high at maturity (c. 2 g H2O g-1 DW). Desiccation tolerance was acquired between 83 and 104 DAP, and was positively correlated with embryo age and dry weight, and negatively correlated with initial water content during this period. Sucrose, the main soluble sugar present throughout embryo development, accounted for an average of 24% of the dry weight. Glucose and fructose contents decreased to less than 1 mg g-1 DW in embryos at maturity. At 117 DAP, as embryos became tolerant to desiccation, the monosaccharides/sucrose ratio fell to 0.015 and raffinose was detected. Stachyose appeared later in 147-day-old embryos and accumulated until shedding. In vitro culture of immature embryos in the presence of high sucrose concentrations (350 and 700 mM) resulted in an increase in their dry weight and a decrease in their water content, and induced the acquisition of desiccation tolerance. Under these conditions, sucrose accumulated in embryos to 30–40% on a dry weight basis, but neither raffinose nor stachyose was detected. Acquisition of desiccation tolerance by oil palm immature embryos was associated both in planta and in vitro with an accumulation of dry matter, a reduction of moisture content, and a fall in the monosaccharides/sucrose ratio. In planta, survival to dehydration was also related with the deposition of oligosaccharides whereas in vitro, it was related with high sucrose accumulation. The role of sugars in the acquisition of desiccation tolerance in oil palm embryos is discussed.