bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum-confined Stark effect in a single InGaN quantum dot under a lateral electric field
Authors: Robinson James W. , Rice James H. , Lee Kwan H. , Na Jong H. , Taylor Robert A. , Hasko David G. , Oliver Rachel A. , Kappers Menno J. , Humphreys Colin J. , Briggs G. Andrew D.
Published: May 2005

The effect of an externally applied lateral electric field upon an exciton confined in a single InGaN quantum dot is studied using microphotoluminescence spectroscopy. The quantum-confined Stark effect causes a shift in the exciton energy of more than 5 meV, accompanied by a reduction in the exciton oscillator strength. The shift has both linear and quadratic terms as a function of the applied field.
High-power continuous-wave midinfrared type-II “W” diode lasers
Authors: Canedy C. L. , Bewley W. W. , Lindle J. R. , Vurgaftman I. , Kim C. S. , Kim M. , Meyer J. R.
Published: May 2005

A type-II “W” diode laser with five quantum well periods and emitting at λ≈3.5μm operated in cw mode to T=218K. A second device produced more than 500mW of cw power at 80K. The threshold current density at T=78K was 31A∕cm2, and pulsed operation was observed to 317K. Improvements over previous single-stage devices for this wavelength range may be attributed in part to high growth quality and also to the incorporation of transition regions that smooth discontinuities in the conduction-band profile.
Resolvin E1, an endogenous lipid mediator derived from omega-3 eicosapentaenoic acid, protects against 2,4,6-trinitrobenzene sulfonic acid-induced colitis
Authors: Arita Makoto , Yoshida Masaru , Hong Song , Tjonahen Eric , Glickman Jonathan N. , Petasis Nicos A. , Blumberg Richard S. , Serhan Charles N.
Published: May 2005

Resolvin E1 (RvE1; 5
S
,12
R
,18
R
-trihydroxyeicosapentaenoic acid) is an antiinflammatory lipid mediator derived from omega-3 fatty acid eicosapentaenoic acid (EPA). At the local site of inflammation, aspirin treatment enhances EPA conversion to 18
R
-oxygenated products, including RvE1, which carry potent antiinflammatory signals. Here, we obtained evidence for reduced leukocyte infiltration in a mouse peritonitis model, where the administration of EPA and aspirin initiated the generation of RvE1 in the exudates. Similar results were obtained with the administration of synthetic RvE1, which blocked leukocyte infiltration. RvE1 also protected against the development of 2,4,6-trinitrobenzene sulfonic acid-induced colitis. The beneficial effect was reflected by increased survival rates, sustained body weight, improvement of histologic scores, reduced serum anti-2,4,6-trinitrobenzene sulfonic acid IgG, decreased leukocyte infiltration, and proinflammatory gene expression, including IL-12 p40, TNF-α, and inducible nitric oxide synthase. Thus, the endogenous lipid mediator RvE1 counter-regulates leukocyte-mediated tissue injury and proinflammatory gene expression. These findings show an endogenous mechanism that may underlie the beneficial actions of omega-3 EPA and provide targeted approaches for the treatment of intestinal inflammation.
AnN-ethyl-N-nitrosourea screen for genes involved in variegation in the mouse
Authors: Blewitt Marnie E. , Vickaryous Nicola K. , Hemley Sarah J. , Ashe Alyson , Bruxner Timothy J. , Preis Jost I. , Arkell Ruth , Whitelaw Emma
Published: May 2005

We have developed a sensitized screen to identify genes involved in gene silencing, using randomN-ethyl-N-nitrosourea mutagenesis on mice carrying a variegating GFP transgene. The dominant screen has produced six mutant lines, including both suppressors and enhancers of variegation. All are semidominant and five of the six are homozygous embryonic lethal. In one case, the homozygous lethality depends on sex: homozygous females die at midgestation and display abnormal DNA methylation of the X chromosome, whereas homozygous males are viable. Linkage analysis reveals that the mutations map to unique chromosomal locations. We have studied the effect of five of the mutations on expression of an endogenous allele known to be sensitive to epigenetic state,agouti viable yellow. In all cases, there is an effect on penetrance, and in most cases, parent of origin and sex-specific effects are detected. This screen has identified genes that are involved in epigenetic reprogramming of the genome, and the behavior of the mutant lines suggests a common mechanism between X inactivation and transgene and retrotransposon silencing. Our findings raise the possibility that the presence or absence of the X chromosome in mammals affects the establishment of the epigenetic state at autosomal loci by acting as a sink for proteins involved in gene silencing. The study demonstrates the power of sensitized screens in the mouse not only for the discovery of novel genes involved in a particular process but also for the elucidation of the biology of that process.
Human modification of global water vapor flows from the land surface
Authors: Gordon Line J. , Steffen Will , Jönsson Bror F. , Folke Carl , Falkenmark Malin , Johannessen Åse
Published: May 2005

It is well documented that human modification of the hydrological cycle has profoundly affected the flow of liquid water across the Earth's land surface. Alteration of water vapor flows through land-use changes has received comparatively less attention, despite compelling evidence that such alteration can influence the functioning of the Earth System. We show that deforestation is as large a driving force as irrigation in terms of changes in the hydrological cycle. Deforestation has decreased global vapor flows from land by 4% (3,000 km
3
/yr), a decrease that is quantitatively as large as the increased vapor flow caused by irrigation (2,600 km
3
/yr). Although the net change in global vapor flows is close to zero, the spatial distributions of deforestation and irrigation are different, leading to major regional transformations of vapor-flow patterns. We analyze these changes in the light of future land-use-change projections that suggest widespread deforestation in sub-Saharan Africa and intensification of agricultural production in the Asian monsoon region. Furthermore, significant modification of vapor flows in the lands around the Indian Ocean basin will increase the risk for changes in the behavior of the Asian monsoon system. This analysis suggests that the need to increase food production in one region may affect the capability to increase food production in another. At the scale of the Earth as a whole, our results emphasize the need for climate models to take land-use change, in both land cover and irrigation, into account.
The importance of weak absorption features in promoting tropospheric radical production
Authors: Matthews Jamie , Sinha Amitabha , Francisco Joseph S.
Published: May 2005

Atmospheric field measurement and modeling studies have long noted discrepancies between observation and predictions of OH and HO
2
concentrations in the atmosphere. Novel photochemical mechanisms have been proposed to explain these differences. Although inclusion of these additional sources improves agreement, they are unable to fully account for the observations. We report and demonstrate the importance of weak electronic absorption features, normally ignored or not measured, in contributing to significant OH radical production. Experiments on methyl hydroperoxide, a prototypical organic peroxide in large abundance in the troposphere, highlights how photochemistry in the neglected electronic absorption tail makes an important addition to the tropospheric OH budget. The present results underscore the need to measure absorption cross sections for atmospheric molecules over a wider dynamic range, especially over the wavelength regions where the solar flux is high, to fully quantitate their contributions to atmospheric photochemistry.
CD147 is a regulatory subunit of the γ-secretase complex in Alzheimer's disease amyloid β-peptide production
Authors: Zhou Shuxia , Zhou Hua , Walian Peter J. , Jap Bing K.
Published: May 2005

γ-Secretase is a membrane protein complex that cleaves the β-amyloid precursor protein (APP) within the transmembrane region, after prior processing by β-secretase, producing amyloid β-peptides Aβ
40
and Aβ
42
. Errant production of Aβ-peptides that substantially increases Aβ
42
production has been associated with the formation of amyloid plaques in Alzheimer's disease patients. Biophysical and genetic studies indicate that presenilin-1, which contains the proteolytic active site, and three other membrane proteins [nicastrin, anterior pharynx defective-1 (APH-1), and presenilin enhancer-2 (PEN-2)] are required to form the core of the active γ-secretase complex. Here, we report the purification of the native γ-secretase complexes from HeLa cell membranes and the identification of an additional γ-secretase complex subunit, CD147, a transmembrane glycoprotein with two Ig-like domains. The presence of this subunit as an integral part of the complex itself was confirmed through coimmunoprecipitation studies of the purified protein from HeLa cells and of solubilized complexes from other cell lines such as neural cell HCN-1A and HEK293. Depletion of CD147 by RNA interference was found to increase the production of Aβ peptides without changing the expression level of the other γ-secretase components or APP substrates whereas CD147 overexpression had no statistically significant effect on Aβ-peptide production, other γ-secretase components or APP substrates, indicating that the presence of the CD147 subunit within the γ-secretase complex down-modulates the production of Aβ-peptides.
The effect of the chemical composition of maize plant lignin on the digestibility of maize stalk in the rumen of cattle
Authors: Cymbaluk Nadia F. , Gordon A. J. , Neudoerffer T. S.
Published: May 2005

1. Digestibility of maize stalk from Troyer Reid (Tr) maize and its isogenic mutant (bm1) was studied by suspending nylon bags containing ground tissue in the rumen of a fistulated steer. The animal was given a grass hay–concentrate (5:3) diet or a maize silage–grass hay–concentrate (4:1:3) diet.

2. The digestibility of the organic matter of the mutant maize stalk was greater than that of the normal maize stalk.

3. Adaptation of the rumen to maize silage increased the organic-matter digestibility of the maize stalk.

4. Lignin content was determined by two methods, namely organic matter insoluble in 72% sulphuric acid (method of the Association of Official Agricultural Chemists, 1960) (AOAC-lignin) and the organic matter lost from the ligno-cellulose complex (represented by acid-detergent fibre) by oxidation with potassium permanganate. The AOAC-lignin concentration was twice the permanganate-lignin concentration, but the amount of lignin estimated by both methods showed a significant negative relation to organic-matter digestibility. The AOAC-lignin concentration was greater in Tr than in bm1 maize but the permanganate-lignin concentration in Tr was slightly lower than in bm1.

5. There was an irregular relationship between the amount of lignin extractable with dimethylformamide (DMF) and digestibility of organic matter due to the solution of some of the DMF-lignin during digestion. The loss of lignin was greater from the mutant maize stalk tissue than from the parent maize stalk tissue.

6. The chemical composition of DMF-lignin determined by analysis showed a significant correlation between the syringealdehyde, p-hydroxybenzaldehyde and vanillin concentrations, and digestibility of organic matter.

7. Higher concentrations of both phenolic aldehydes and acids were found in the less digestible Tr material than in the bm1 stalk tissue.
Rate of passage of digesta in sheep
Authors: Grovum W. L , Williams V. J
Published: May 2005

1. Sheep given 400 and 1200 g lucerne chaff/d in equal hourly meals were infused continuously with the complex51Cr EDTA into the rumen for 5 d and then slaughtered. The retention times of51Cr EDTA along the small intestine and the apparent quantities of water absorbed in the small and large intestines were calculated.

2. The apparent quantities of water absorbed for the 400 and 1200 g food intakes were 5844 and 13110 ml/d in the small intestine and 2101 and 8520 ml/d in the large intestine respectively.

3. The mean total retention times of51Cr EDTA in the small intestine were 136 and 91 min for the sheep given 400 and 1200 g/d respectively. The marker was retained up to seventeen times longer in the ileal than in the duodenal or proximal jejunal segments.
Effect of an adequate-protein diet after a low-protein diet on protein catabolism in growing rats
Authors: Horie Yoshimitsu , Ashida Kiyoshi
Published: May 2005

1. Metabolic alterations related to protein catabolism were studied in rats in transitional states induced by changing from a low-protein (LP) (50 g casein/kg) diet to a high-protein (HP) (250 g casein/kg) diet.

2. Twenty-four hours after the diet was changed, the rats showed a more rapid increase in live-weight gain than controls that had been fed on the HP diet throughout. On the 5th day after the diet change, their increase in body-weight had returned almost to the control rate. Food and therefore nitrogen intakes on the 1st and 5th days after the change in diet were the same as those of the controls. It seems likely therefore that the initial high rate of live-weight gain is an indication of a metabolic adaptation which occurred on the LP diet and which did not fully return to normal until the 5th day after the change of diet.

3. N balance was higher 24 h after the change in diet than in the controls, owing to a reduction in total urinary N and in urea excretion, but when measured on the 5th day it was similar in both groups.

4. Carcass N determination showed that, after 7 d on the LP diet total-, trichloroacetic acid (TCA)-soluble- and TCA-insoluble-N contents (in terms of mg/g rat) were all slightly lower than control values but they had almost returned to normal 5 d after the diet change. There was a significant increase in the TCA-soluble-N content after 24 h on the HP diet to a value greater than the control value.

5. Proteolysis was measured in vitro by incubation of liver slices and diaphragms under anaerobic conditions. With liver slices it was significantly lower 24 h after the diet change than in control rats. On the 5th day it was significantly higher than 24 h after the diet change but had not quite reached the control level. In the diaphragm, proteolysis was also lower 1 d after the diet change, and had not increased at all by the 5th day.

6. Ureogenesis in the liver was reduced significantly 24 h after the diet change and it had almost returned to the control level on the 5th day. On the other hand, arginase (L-arginine amidinohydrolase;EC3·5·3·1) activity was significantly lower 24 h after the diet change and did return completely to the control level on the 5th day.

7. These results show that the initial increased N balance and reduced N excretion were due to enzymic adaptation to the LP diet, the reduced N excretion being attributable to reduction in hepatic urea production.
Degradation of riboflavin by alimentary bacteria of the ruminant and man: production of 7,8-dimethyl-10-carboxymethylisoalloxazine
Authors: West D. W. , Oiven E. C.
Published: May 2005

1. A new product of the bacterial degradation of riboflavin has been isolated from fermentations in vitro of mixtures of either rumen bacteria or caecal bacteria with excess of the vitamin.

2. This product has been identified as 7,8-dimethyl-10-carboxymethylisoalloxazine and has also been shown to occur in the urine of ruminants and man.

3. The bacterial formation of this compound is compared with the bacterial formation of other isoalloxazines previously identified in similar incubation mixtures, and is discussed in relation to the factors influencing the mode of degradation of riboflavin.
Metabolism of riboflavin:reduction of 7,s-dimethyl-10-formylmethylisoalloxazine by an enzyme in liver
Authors: West D. W. , Owen E. C.
Published: May 2005

1. The riboflavin metabolite, 7,8-dimethyl-10-formylmethylisoalloxazine, has been shown to be reduced to the corresponding alcohol, 7,8-dimethyl-10-(2′-hydroxyethyl)isoalloxazine, by an enzyme present in the soluble fraction of liver and kidney.

2. The enzyme is present in these organs in a number of species but is especially prevalent in the tissues of ruminants. It appears to be different from the normal hepatic alcohol dehydrogenase in that it uses NADPH rather than NADH as cofactor.
Notes on a deamination method proposed for determining ‘chemically available lysine’ of proteins
Authors: Allison R. M. , Laird W. M. , Synge R. L. M.
Published: May 2005

1. Details of a chemical method, using acetic acid and sodium nitrite, for determining ‘available lysine’ in plant materials are given. An analytical procedure was used which distinguished lysine from ornithine; the latter was liable to arise in the course of the deamination and hydrolysis procedure.

2. The experimentally determined ‘available lysine’ contents of various samples of leaf-protein concentrates showed significant positive correlations with previously reported values for their biological value and true digestibility. ‘Available lysine’correlated significantly with total lysine liberated by direct acid hydrolysis.
Relationships between copper, zinc and iron in the plasma, soft tissues and skeleton of the rat during Cu deficiency
Authors: Alfaro Begona , Heaton F. W.
Published: May 2005

1. The effect of dietary copper deficiency on the distribution of Cu, zinc and iron between plasma, various soft tissues and bone was investigated in weanling male rats.

2. The concentration of Cu decreased in plasma, liver, kidney and femur, and the concentration in plasma correlated with that in all three organs. The total amount of Cu in the liver was reduced over the whole depletion period and a net loss from kidney also occurred over a shorter period, indicating that liver and, to a lesser extent, kidney both provide a mobilizable reserve of Cu.

3. Animals in galvanized cages developed Cu deficiency more rapidly than similar rats in stainless-steel cages owing to Zn aggravating the depletion. Zn accumulated in the liver and femur of Cu deficient rats, particularly when they were housed in galvanized cages.

4. Cu-deficient animals accumulated Fe in the liver, but had reduced concentrations in plasma, kidney and spleen. The hypertrophy of the heart and bone-marrow observed in Cu-deficient rats appeared to be secondary to the anaemia resulting from this impaired mobilization of hepatic Fe.
Short-term effects of feeding rats with glucose syrup fractions and dextrose
Authors: Birch G. G. , Etheridge I. J. , Green L. F.
Published: May 2005

1. Young female Wistar rats were fed for 18 d on diets containing dextrose, 43 dextrose equivalent (DE) glucose syrup, fractions of 43 DE glucose syrup of high and low molecular weight or sucrose.

2. All rats gained weight and showed no gross external abnormalities or significant dental caries scores.

3. The concentrations of cholesterol, triglycerides, free fatty acids and glucose were determined in samples of liver and serum. Generally, these values tended to increase with increasing molecular weight of dietary carbohydrate in the order dextrose, glucose syrup fraction of low molecular weight, and glucose syrup fraction of high molecular weight.

4. Rats given the high-molecular weight glucose syrup fraction were found to have caecums twice the normal size.
Lesions produced by copper deficiency in neonate and older rats
Authors: Hall G. A. , Howell J. McC.
Published: May 2005

1. Three groups of rats of different mean weights were given a diet of milk treated with hydrogen sulphide and supplemented with copper-free minerals and vitamins. Also divided into three groups of similar weights were rats given the same diet supplemented with 500 μg Cu/week and stock rats which were given a commercial diet.

2. In a second experiment eight adult female rats were given the Cu-deficient diet for 2 weeks before mating and during pregnancy, and in a third experiment were mated and immediately after mating were given the Cu-deficient diet or the Cu-supplemented diet.

3. Cu deficiency reduced the growth rate of younger rats but had a much less marked effect on the weight of more mature rats. Achromotrichia appeared at 5 weeks; diarrhoea, with the faeces frequently containing undigested blood, and subcutaneous oedema were terminal changes. Deaths occurred in the youngest group of rats after 9 weeks and later in heavier, older rats.

4. Histological changes were seen in livers, spleens, testes and epididymes but not in blood vessels or bones.

5. Pups were not born to mothers given the deficient diet before mating, and the pups from mothers given the deficient diet only during pregnancy were born dead or showed congenital abnormalities.

6. Foetal and liver Cu concentrations for the various groups of animals are given.

7. Maintenance of the foetus appears to be the biological process most susceptible to Cu deficiency in the rat.
The composition of chinchilla milk
Authors: Volcani R. , Zisling Kivka , Sklan D. , Nitzan Zafrira
Published: May 2005

1. The composition of the milk ofChinchilla chinchilla chinchillawas determined throughout lactation in twenty-eight chinchillas. The amino acid pattern of the protein and the fatty acid composition of the milk were determined, and the effect of three different diets on the milk composition was studied.

2. The milk contained (g/kg): 64–80 protein, 108–156 fat, 17 lactose and 10 ash.

3. Paper and polyacrilamide gel electrophoresis showed four additional protein fractions that are not apparent in bovine milk protein.
The effect of a low-fat maternal diet on neonatal rats
Authors: Sinclair A. J. , Crawford M. A.
Published: May 2005

1. Rats were raised on a low-fat diet containing 6 g fat/kg. Females of the second generation were bred and only 11% of their pups survived to weaning age compared with a 66% survival for control pups. Pups were killed 8–12 h after birth and their tissues were analysed.

2. Pups in the low-fat group had smaller body, brain and liver weights than control pups; the lipid contents of body, brain and liver were also significantly less.

3. In the liver triglycerides from the control group the C20and C22polyenoic fatty acids constituted 33% of the total fatty acids. The liver triglyceride concentration in the low-fat group was lower and the concentration of the long-chain polyenoic fatty acids in this fraction was 20% of the control value. The milk fatty acids from the low-fat group contained only 33% as much of the C18to C22polyenoic fatty acids compared with the control group.

4. In the brain lipids from the low-fat group, changes in the fatty acid composition were less marked than in the liver lipids. In these experiments there were only small amounts of 20:3ω9 in the tissue lipids; the ratio to 20:4ω6 was less than 1.

5. These changes are discussed in relation to the influence of dietary lipids on tissue growth especially of lipid-rich tissues such as the brain.
The metabolism of some folates in the rat
Authors: Beavon J. R. G. , Blair J. A.
Published: May 2005

1. A number of folates labelled with 14C were administered orally to rats, at various doses, and urinary, faecal and hepatic folates examined.

2. 10-Formylpteroylmonoglutamic acid (10CHO—PGA) entered the folate pool very slowly, and is thought to be relatively ineffective in nutrition.

3. 10-Formyl[2-14C]tetrahydrofolic acid (10CHO—[2-14C]THF) entered the folate pool very rapidly. 5-Methyl[2-14C]tetrahydrofolate (5CH3—[2-14C]THF) was the major urinary folate.

4. 5-Formyl[2-14C]tetrahydrofolic acid (5CHO—[2-14C]THF) entered the folate pool only to a small extent. 5CHO—[2-14C]THF, given intravenously, produced no urinary 5CH3—[2-14C]THF in the first 6 h.

5. 10-Methylidyne[2-14C]tetrahydrofolic acid was metabolized to an extent which was dependant on the dose. At doses of 3 and 30 μg/kg body-weight, 5CH3—[2-14C]THF represented 5·4 and 20% respectively of urinary folates and for 10CHO—[2-14]PGA, the values were 16% of total urinary folates after the higher dose, and 78·5% after the lower dose.

6. Results obtained for the metabolism of 5CH3—THF varied depending on the position of the labelling: 514CH3–THF gave no labelled urinary folate, the methyl group being lost rapidly. When 5CH3—[2-14C]THF was given, it appeared as the major urinary folate.

7. Folates found in the liver after oral administration of labelled folates were identified by thin-layer chromatography; only folate monoglutamates were identified.
Ascorbic acid and long-term anticonvulsant therapy in children
Authors: Dawson K. P. , Duncan Anne
Published: May 2005

1. Forty-eight children, who were long-term hospital patients, were investigated to assess their leucocyte ascorbic acid status.

2. Twenty-nine children had been receiving long-term anticonvulsant therapy, and these children did not have a significantly lower level of ascorbic acid than the untreated group, which did not have epilepsy.

3. The ascorbic acid levels of all subjects were low and seventeen had levels between 7·3 and 16·0 μg/108 white blood cells.
The effect of different feeds, including those containing soya-bean products, on the passage of digesta from the abomasum of the preruminant calf
Authors: Smith R. H. , Sissons J. W.
Published: May 2005

1. The effects of various factors on rates of flow and composition of digesta leaving the abomasum of preruminant calves were studied. The possible relation of some of these effects to the development of serum antibodies to certain dietary constituents has also been examined. Two situations were distinguished: (a) unsensitized responses, shown by calves receiving milk protein or soya-bean products for the first one or two occasions; (b) sensitized responses, shown by calves receiving certain soya-bean products, after a number of these feeds had been given.

2. For unsensitized calves, the rate of flow of total digesta from the abomasum was greater in the first few hours after a feed consisting of a mineral solution was given, than after cow's milk was given. This difference was apparently due to differences in the composition of digesta entering the duodenum. Total digesta flows after giving synthetic milk feeds, prepared from different protein sources, were similar to those after cow's milk was given.

3. For sensitized calves, rates of flow of total digesta from the abomasum were greatly affected by the nature of the protein source used in the diet. Soya-bean flour (heated or unheated) generally caused inhibition of flow for some hours after feeding; a soya-bean protein isolate (isoelectric) had a similar but smaller effect, but a soya-bean concentrate (prepared by alcohol extraction of a soya-bean flour) and milk protein had little or no effect. The inhibition, believed to be a sign of more general disorders, appeared to be caused by a factor entering the duodenum which induced a change in the way in which the calf responded, probably as the result of a gastrointestinal allergy.

4. Calves given soya-bean flour or a soya-bean protein isolate (isoelectric) in their diets for several weeks, showed respectively high and low titres of serum antibodies to an antigen prepared from soya-bean flour. Calves given alcohol-extracted soya-bean concentrate had no similar antibodies.

5. In addition to variations in total digesta flow, dietary nitrogen compounds were held up in the abomasum to different extents after different feeds. After a whole-milk feed or a synthetic feed prepared from casein, a slow, steady release of N occurred over at least 9 h. N hold-up after giving soya-bean-containing feeds was slight for the soya-bean flour, but extremely marked for the soya-bean protein isolate (isoelectric). The latter hold-up was followed after several hours by a rapid outflow of N from the abomasum.
The absorption of iron, with or without supplements of single amino acids and of ascorbic acid, in healthy and Fe-deficient children
Authors: El-Hawary M. F. S. , El-Shobaki F. A. , Kholeif T. , Sakr R. , El-Bassoussy M.
Published: May 2005

1. Studies were done on the effect of ascorbic acid and five amino acids (histidine, cystine, cysteine, valine and glutamic acid) on intestinal iron absorption in a group of ninety Egyptian infants and young children, of which fifty-seven were healthy controls and thirty-three were suffering from Fe-deficiency anaemia.

2. Supplements tested promoted Fe absorption in healthy controls in the following order: valine > histidine > ascorbic acid. Cysteine, glutamic acid and cystine were found to have no significant effect.

3. Supplementation with valine, ascorbic acid and histidine also increased intestinal Fe absorption in anaemic subjects, but to a lesser extent than in controls.

4. Supplementation of haematinic therapy with these compounds is recommended. Their use is also suggested to improve the availability of the Fe content of everyday diets.
An abnormality of the bone marrow associated with vitamin E deficiency in sheep
Authors: Kimber R. J. , Allen Shirley H.
Published: May 2005

1. Sheep fed on a maintenance ration of wheaten-hay chaff or of wheaten-hay chaff–lucerne-hay chaff (1:1, w/w) became deficient or incipiently deficient in vitamin E.

2. Degenerative changes were observed in bone marrow and muscle, and liver function was impaired in some animals. These abnormalities were not influenced by the vitamin B12status of the animals or by a shortage of cobalt in the rumen.

3. Plasma ascorbic acid levels may not have been optimum, and folic acid may not have been fully utilized by some sheep.

4. Liver function responded fairly rapidly to α-tocopheryl acetate, but skeletal muscle had not returned to normal after 28 weeks of treatment. A variable trend towards normal cellularity was found in bone marrow following supplementation with α-tocopheryl acetate.

5. A secondary deficiency or, alternatively, inefficient excretion or metabolism of a toxic material, may occur in vitamin E deficiency as a result of degenerative changes in the absorptive or excretory areas of the intestinal tract and be responsible for the bone marrow abnormality.
Effect of different regimens of early malnutrition on behavioural development and adult avoidance learning in Swiss white mice
Authors: Bush Maureen , Leathwood P. D.
Published: May 2005

1. The effects of perinatal malnutrition on behavioural development and adult shuttle-box avoidance performance were studied in Swiss white mice.

2. Mice were malnourished (a) from the 7th day of gestation until birth, (b) from birth until weaning, or (c) during both gestation and the sucking period.

3. Pups born of protein-restricted mothers had reduced birth weights, retarded development and poor adult avoidance performance, even if reared from birth by well-nourished mothers.

4. Postnatal malnutrition, induced either by restricting maternal diet or by rearing in large litters, retarded development during the second half of lactation and lowered subsequent adult avoidance performance.
Effects of ingestion of organic selenium in adapted and non-adapted rats
Authors: Jaffe W. G. , Mondragon Cristina
Published: May 2005

1. Rats were given moderate-selenium (4·5 mg/kg) or low-Se (0·5 mg/kg) diets during gestation and lactation. Their young were given diets with high (10 mg/kg), moderate or low Se contents from weaning, and groups of rats were killed at intervals during the 14-week experimental period.

2. Compared with young rats which received the low-Se diet, those which received the moderate- or high-Se diets had a high incidence of liver lesions and there were changes in liver Se content, haemoglobin concentration, packed cell volume, prothrombin activity, fibrinogen content, spleen weight, body water and serum glutamic–oxaloacetic and glutamic–pyruvic transaminase (L-aspartate: 2-oxoglutarate aminotransferase; EC 2.6.I.I and L-alanine: 2-oxoglutarate aminotransferase; EC 2.6.I.2 respectively) and alkaline phosphatase (EC 3.I.3.I) activities. In those rats which received the high-Se diet the changes were more pronounced than in those which received the moderate-Se diet.

3. In young rats from dams given moderate-Se diets, which were themselves given the moderate-Se diet, the liver Se content decreased continuously, whereas rats given the same diet but from dams which had received the low-Se diet, the liver Se content increased continuously. There was a slight improvement of symptoms of Se toxicity in all groups by the 5th week of the experimental period.

4. The results suggest that there was an adaptation to chronic Se intake.
Effects of live weight and energy intake on nitrogen balance and total N requirements of lambs
Authors: Black J. L. , Griffiths D. A.
Published: May 2005

1. Results of 298 nitrogen balance studies from experiments with male cross-bred lambs, ranging in weight from 3 to 38 kg, which had been either fasted, or fed entirely on liquid diets of varying protein content at various energy intakes up to ad lib. intake, were used to quantitatively describe the effects of the amount and quality of absorbed protein, energy intake and live weight on N balance and total N requirement of lambs.

2. When N intake was less than the amount required, N balance was independent of energy intake, but linearly related to absorbed N and metabolic body-weight (live weight0·75). In the fitted relationship, the coefficient of absorbed N was shown to be an estimate of the biological value of absorbed protein and the coefficient of metabolic body-weight was an estimate of the loss of endogenous N in both urine and faeces. For the milk-based diets used in the experiment biological value was 0·72 and the total endogenous N loss in urine and faeces was 148 mg N/kg0·75 per d.

3. When N intake was in excess of the amount required, N balance in lambs of a constant live weight increased linearly with metabolizable energy (ME) intake, at a rate that decreased with increasing live weight. Similarly at constant ME intake, N balance was a curvilinear decreasing function of metabolic body-weight. When N balance was expressed per unit metabolic body-weight, it was constant for lambs of all weights when ME intake was about 0·23 MJ/kg0·75 per d, but it decreased linearly with increasing metabolic body-weight for ME intakes above this level.

4. N balance of fasted lambs was several times less than predicted by either of the relationships established for fed animals, and was found to be linearly related to metabolic body-weight.

5. The effects of energy intake and live weight on the total N requirement of lambs were determined. When total N requirement was expressed per unit of energy intake, it was found to be constant at 0·9 g N/MJ ME for all lambs irrespective of live weight when ME intake was 0·23 MJ/kg0·7 per d. However, as ME intake/unit metabolic body-weight was raised above this level, N requirement/unit ME intake increased for lambs weighing less than c. 23 kg, but decreased for heavier animals.
Vitamin B12 nutrition and metabolism in the baboon (Papio cynocephalus)
Authors: Siddons R. C. , Jacob Fredericka
Published: May 2005

1. Measurement of the vitamin B12 content of baboon tissues showed that the liver contained the highest concentration, followed by the pituitary, kidney, heart, spleen and pancreas.

2. The dietary vitamin B12 requirement of the baboon for the maintenance of satisfactory body stores was between 1 and 2 μg/d.

3. Satisfactory liver vitamin B12 stores were invariably associated with serum levels above 125 pg/ml, whereas liver levels were usually low when the serum level was below 50 pg/ml.

4. Increased methylmalonic acid (MMA) excretion after a valine load occurred when the liver vitamin B12 level was less than 0·40 μg/g. L- and DL-valine were approximately equally effective as precursors of MMA, whereas sodium propionate, whether given orally or intra-peritoneally, was less effective.

5. The distribution of radioactivity along the wall of the intestinal tract after an oral dose of [57Co]cyanocobalamin suggested that the distal half of the small intestine was the main site of vitamin B12 absorption. However, the utilization of vitamin B12 put direct into the middle part of the small intestine was much lower than that of an oral dose.

6. The unsaturated vitamin B12-binding capacity of baboon serum was not related to the serum vitamin B12 level. There was a significant difference between the unsaturated vitamin B12-binding capacities of the two subspecies of baboon (Papio cynocephalus cynocephalus and P. cynocephalus anubis) studied.
Metabolism of propionate in the tissues of the sheep gut
Authors: Weeks T. E. C. , Webster A. J. F.
Published: May 2005

1. The extent of propionate metabolism during absorption from the gut and the amounts of L-lactate formed and glucose utilized by the portal-drained viscera were determined in conscious sheep from measurements of portal venous blood flow and portal venous and aortic metabolite concentrations. The sheep were fasted overnight and given primed continuous intraruminal infusions of volatile fatty acids (VFA) at two rates, supplying propionate at 40·0 and 79·9 mmol/h. Measurements were made during the 5th and 6th hours of the infusion, when rumen liquor VFA concentrations were constant.

2. The rate of L-lactate formation by the portal-drained viscera was not affected by the VFA infusions and accounted for approximately 15 % of the probable total lactate entry rate.

3. Considerable amounts of glucose were taken up by the portal-drained viscera, amounting to approximately 35 % of the probable glucose entry rate. If this glucose was metabolized through the glycolytic pathway, this would at all times have accounted for the amounts of L-lactate formed.

4. Portal venous blood flow was positively correlated with VFA infusion rates and with the net amount of propionate appearing in the portal blood.

5. It is concluded that although propionate may be metabolized by the rumen epithelium, the unique pathway of L-lactate formation from propionate is of limited quantitative significance to the animal, although it may be of importance to the rumen epithelium itself.
The influence of essential fatty acids and food restriction on the specific activities of hepatic lipogenic and glutamate-metabolizing enzymes in the laying hen
Authors: Balnave D.
Published: May 2005

1. Extended feeding of an essential fatty acid (EFA)-deficient diet to laying hens increased liver size and liver lipid concentration.

2. The specific activities of hepatic lipogenic and glutamate-metabolizing enzymes were increased by feeding the EFA-deficient diet.

3. Restriction of daily food intake to 75 % ofad lib. intake did not affect the response to dietary fat concentration.

4. Hepatic enzyme activities in hens fed on restricted amounts of food and killed just before, or after, the normal daily feeding time indicated no reduced capacity for lipogenesis at the earlier time.
A relationship between the molar proportion of propionic acid and the clearance rate of the liquid phase in the rumen of the sheep
Authors: Hodgson J. C. , Thomas P. C.
Published: May 2005

1. Four rumen-cannulated sheep were given a forage mixture (F) of chopped hay–ground, pelleted, dried grass (92:8, w/w) and two concentrate mixtures (C and S) of ground barley–ground hay–flaked maize (46:24:30 and 56:24:20, by wt respectively) in twenty-four hourly meals each day. Each of the diets was offered in successive periods of 16 d to give a feeding sequence F–S–C–S for one pair of sheep and C–S–F–S for the other pair.

2. The average composition (mol/100 mol) of the mixture of short-chain fatty acids, acetic, propionic and butyric, in the rumen was respectively 70·1, 18·5 and 7·5 with diet F, and 55·8, 24·8 and 13·6 with diet C. With diet S, the pattern of fermentation varied both between animals and in the same animal for different periods having either ‘high’(28–39 mol/100 mol) or ‘low’(16–21 mol/100 mol) proportions of propionic acid. On average when diet S followed diet F there was less propionic acid in the fermentation mixture than when diet S followed diet C (59·3 acetic, 22·2 propionic and 14·I butyric as compared with 52·7, 29·4 and 13·I respectively) but this trend was not significant and there was evidence of interactions between the feeding sequences and the individual sheep.

3. The mean concentrations of ammonia, sodium, potassium and chloride were similar for all diets but the pH and concentrations of calcium, magnesium and phosphorus tended to be higher and the buffering capacity lower for diet F than for diets C or S. In animals receiving diet S there was no relationship between the concentrations of minerals, the pH or buffering capacity and the pattern of fermentation except for ammonia, the concentration of which was high when the molar proportion of propionic acid was low.

4. Rumen volume, outflow rate and clearance rate, determined using polyethylene glycol, were higher for diet F than for diets C and S but within each diet, particularly for diet S, values varied considerably between sheep and between periods.

5. There was evidence of an interrelationship between the molar proportion of propionic acid in the fermentation products and the clearance rate, which indicated that the clearance rate may be an important factor influencing the pattern of fermentation in the rumen.
Energy balance and metabolic rate in preterm infants fed with standard and high-energy formulas
Authors: Brooke O.G.
Published: May 2005

1. Energy balances were performed on sixteen low birth weight preterm infants over 7–10 d periods on a standard low-solute infant formula (2600 kJ/l), and on four high-energy formulas, providing different energy densities up to 3760 kJ/l. In two of the high-energy formulas the additional fat energy was provided by peanut oil, and in the other two by medium chain triglycerides (MCT). Anthropometric measurements and metabolic rate (MR) determinations were made during the balance periods.

2. Mean energy retention on the standard formula was 66% of the intake and declined to below 50% on the two feeds providing the highest energy. Extensive energy balance data on the standard formula are available for reference.

3. Net absorption of dietary energy increased on all the high-energy formulas, rising from 362 kJ/kg per d on the standard formula to 453 kJ/kg per d on the highest energy-formula (P< 0.001). There was no advantage in using MCT.

4. Net absorption of dietary energy improved with advancing maturity, irrespective of the formula.

5. In spite of the increased dietary energy retention, there was no increase in growth rate during periods of feeding with the high-energy formulas.

6. Fasting and postprandial MR increased by 10.4 and 12.8% respectively on the highest energy feeds.

7. It is concluded that, at least in the short term, this type of high-energy feeding increases MR at the expense of growth and thus is probably of no advantage to the infant.
Studies on copper and cobalt in dairy calves
Authors: Maro J. K. , Kategile J. A. , Hvidsten H.
Published: May 2005

1. Studies on the effect of supplementing copper and cobalt were conducted in 4- to 10-month-old dairy calves during successive indoor and outdoor feeding periods on conserved forges and fresh pastures respectively.

2. No significant differences in live-weight gains or serum Cu were recorded during the indoor period of 40 d.

3. Both live-weight gains and serum Cu were significantly elevated (P< 0.05) by Cu supplementation during the following grazing period of 70 d.

4. Supplementation with Co alone had no effect on any of the measurements taken, but it had an additive effect on weight gains to Cu supplementation during the grazing period.

5. It is concluded that Cu deficiency at marginal level is prevalent in the Mbeya area of Tanzania and that this is due to low Cu and high molybdenum in herbage.
The effect of restricted grazing on the fatty acid composition of ovine rnilk fat during early lactation
Authors: Payne E. , Rattray P. V.
Published: May 2005

1. The fatty acid composition of milk fat of Coopworth sheep offered varying pasture allowances has been determined after 1, 14 and 35 d of lactation. Differences in fatty acids occurred, particularly between 1 and 14 d, with a major increase in C18:0 whilst C16:0, C14:0 and C18:3 showed decreases.

2. When pasture allowances were restricted there were decreases in the short-chain fatty acids from C6 to C14 and an increase in C18:1 as has been observed previously for cattle. The C18:1:C10 value is a convenient measure of these changes and can be determined more rapidly than determining all the lower fatty acids.

3. The increased demand for milk resulting from suckling twin lambs caused an increase in C18:1 and decreases in C10 and C12 due to an increased utilization of body reserves.

4. The level of linoleic acid was much greater than has been previously observed in sheep given hay and contributes to the rapid rise in linoleic acid levels in lambs born under grazing conditions.
Metabolic effects of a low-magnesium diet in pigs
Authors: Nuoranne P. J. , Raunio R. P. , Saukko P. , Karppanen H.
Published: May 2005

1. Pigs were fed on semi-purified food. The magnesium content of the experimental diet was 1·0 and that of the control diet 1·9 g/kg.

2. In the low-Mg group serum triglycerides and blood lactate values were increased and base excess and standard bicarbonate values were decreased, indicating metabolic acidosis.

3. A significant positive dependence was found between blood pH and serum Mg:Ca value as well as between blood pH and serum Mg, and also between body temperature and blood lactate values in the low-Mg group. None of these dependences was significant in the control group with magnesium acetate supplementation in the food.

4. No specific histopathological changes were found in heart, liver or kidney of the experimental animals.

5. The results indicate that an increase in serum triglycerides does not need to depend on the amount or quality of food fat.

6. The present study shows that, in pigs, a low-Mg diet may cause metabolic disturbances in instances when the food Mg content is distinctly higher than the normal values recommended by the (UK) Agricultural Research Council (1966) and (US) National Research Council (1968).
Variations through the day of hepatic and muscular cathepsin A (carboxypeptidase A;EC3.4.12.2), C (dipeptidyl peptidase;EC3.4.14.1) and D (endopeptidase D;EC3.4.23.5) activities and fee amino acids of blood in rats: influence of feeding schedule
Authors: Arnal Christiane Obled M. , Valin C.
Published: May 2005

1. Growing rats were fed eitherad lib.or with six (equal) meals offered every 4 h (form 10.00 hours). Rats of each group were killed at intervals of 4 h begining at 11.00 hours. Activities of cathepsin A (carboxy-peptidase A;EC3.4. 12. 2), C (dipeptidyl peptidase;EC3.4.14.1) and D (endopeptidase DEC3.4.23.5) were measured in liver and muscle homogenates and free amino acids in blood were determined.

2. In the rats fedad lib.activities of carboxypeptidase A and endopeptidase D in liber and muscle showed significant variation, with maximum activity in the light period. In general, meal-feeding only caused minor differences in cathepsin activities; although significant differences occurred for carboxypeptidase A. For the latter enzyme a peak in activity occurred in the dark as well as in the light period.

3. Irrespective of the feeding schedule, the lower concentration of free essential amino acids of blood occurred generally during the night period. With the controlled-feeding schedule there is an increase of essential amino acids and a slight decrease of non-essential amino acids of blood.