bluuebunny/crossref_metadata_2025 huggingface dataset:
Epidermal growth factor prevents prepartum luteolysis in the rat
Authors: Ribeiro M. L. , Aisemberg J. , Billi S. , Farina M. G. , Meiss R. , McCann S. , Rettori V. , Villalón M. , Franchi A. M.
Published: May 2005

We have previously reported that intrauterine (i/u) administration of epidermal growth factor (EGF 500 ng) on day (d) 21 of pregnancy delayed 19.0 ± 0.6 h the onset of labor. Progesterone (P) is secreted by ovarian corpora lutea (CL) throughout gestation in the rat. Prepartum CL regression due to increased uterine cyclooxygenase I and prostaglandin F
2α
results in P withdrawal followed by labor. The aims of the present work were (
i
) to study whether EGF delayed-onset of labor was mediated by a mechanism that prevented CL regression; (
ii
) to determine amniotic fluid (AF) EGF in pregnant rats. Rats on d21 of pregnancy received i/u EGF (500 ng) and were killed 0, 4, 8, 12, 24, and 48 h later. Control AF from rats on d13 and 18–22 of pregnancy was obtained. EGF decreased uterine prostaglandin F
2α
synthesis 8 h after treatment. Twelve hours after EGF injection, P reached its highest serum level and uterine cyclooxygenase I expression was undetectable. CL from rats killed 8 and 12 h after EGF were similar to those from rats on d13 of pregnancy, when serum P is maximum. EGF in AF increased throughout gestation, reached a maximum on d21, and decreased before the onset of labor. We suggest that the effect of EGF on the onset of labor was mediated by an early effect on the uterus that prevented prepartum CL regression.
A quantum mechanical polarizable force field for biomolecular interactions
Authors: Donchev A. G. , Ozrin V. D. , Subbotin M. V. , Tarasov O. V. , Tarasov V. I.
Published: May 2005

We introduce a quantum mechanical polarizable force field (QMPFF) fitted solely to QM data at the MP2/aTZ(-hp) level. Atomic charge density is modeled by point-charge nuclei and floating exponentially shaped electron clouds. The functional form of interaction energy parallels quantum mechanics by including electrostatic, exchange, induction, and dispersion terms. Separate fitting of each term to the counterpart calculated from high-quality QM data ensures high transferability of QMPFF parameters to different molecular environments, as well as accurate fit to a broad range of experimental data in both gas and liquid phases. QMPFF, which is much more efficient than
ab initio
QM, is optimized for the accurate simulation of biomolecular systems and the design of drugs.
ExsE, a secreted regulator of type III secretion genes in
Pseudomonas aeruginosa
Authors: Rietsch Arne , Vallet-Gely Isabelle , Dove Simon L. , Mekalanos John J.
Published: May 2005

Type III secretion systems are toxin delivery systems that are present in a large number of pathogens. A hallmark of all type III secretion systems studied to date is that expression of one or more of their components is induced upon cell contact. It has been proposed that this induction is controlled by a negative regulator that is itself secreted by means of the type III secretion machinery. Although candidate proteins for this negative regulator have been proposed in a number of systems, for the most part, a direct demonstration of their role in regulation is lacking. Here, we report the discovery of ExsE, a negative regulator of type III secretion gene expression in
Pseudomonas aeruginosa
. Deletion of
exsE
deregulates expression of the type III secretion genes. We provide evidence that ExsE is itself secreted by means of the type III secretion machinery and physically interacts with ExsC, a positive regulator of the type III secretion regulon. Taken together, these data demonstrate that ExsE is the secreted negative regulator that couples triggering of the type III secretion machinery to induction of the type III secretion genes.
Digestion of carbohydrates of hay in small ruminants
Authors: Porter P. , Singleton A. G.
Published: May 2005

1. An analytical scheme for the separation and identification of carbohydrates in food, duodenal contents and faeces of sheep is described.

2. This scheme was applied to three sheep and one goat given hay diets, and the quantities of carbohydrates disappearing from the rumen and intestine respectively were assessed by reference to faecal lignin. Results indicated that 95–100% of digestible cellulose and 96–99% of digestible pentosan disappeared from the rumen.

3. In an investigation of the microbial fraction of duodenal contents in the goat it was estimated that approximately 6 g carbohydrate passed to the duodenum per 24 h. Glucose accounted for a little over half of this amount.
The content of vitamin E in British diets
Authors: Smith C. L. , Kelleher J. , Losowsky M. S. , Morrish Nora
Published: May 2005

1. Analysis of whole daily diets of normal subjects and of diets prepared in hospital to resemble the home diets of ambulant hospital patients showed that the majority of diets in Britain have a vitamin E content less than the lowest recommended intake of 5 mg/d, despite being generally satisfactory in calorie, protein and fat contents.

2. Comparison of measured intake of vitamin E with the intake calculated from food tables showed that the use of such tables may be unreliable.

3. Analyses of selected representative foods and of duplicate whole diets showed that the variations between measured vitamin E content of diets and those calculated from tables may be largely due to the great variability of tocopherol concentration in apparently similar samples of food.
Fatty acid composition of liver lipids of young lambs
Authors: Noble R. C. , Steele W. , Moore J. H.
Published: May 2005

1. The changes in the lipid compositon of livers from lambs receiving either ewe's milk or a reconstituted low-fat milk powder have been studies during the first 8 d after birth.

2. At birth the phospholipid and unesterified fatty acid fractions constituted the major proportion of the liver lipids. In the lambs on the artificial diet the relative concentration of the phospholipid fraction increased and there were corresponding decreases in the relative concentrations of all the other fractions, whereas in the naturally fed lambs the relative concentration of the phospholipids remained similar to that found in the livers at birth.

3. In the liver lipids at birth there were only low concentration of the C18polyunsaturated fatty acids, althoughts there were appreciable concentrations of the higher C20and C22polyunsaturated fatty acids.

4. After birth there was a large increase in the concentration of the C18polyunsaturated fatty acids in the livers of the lambs on the natural diet and a decrease in the 20:3ω9:20:4ω6 (triene:tetraene) ratio. In the lambs receiving the artificial diet the concentration of the C18polyunsaturated fatty acids and the trience:tetraene ration remained similar to that observed at birth.

5. These changes are discussed in relationship to the metabolism of the essential fatty acid in monogastric animals.
Relative palatability to sheep of straw, hay and dried grass
Authors: Greenhalgh J. F. D. , Reid G. W.
Published: May 2005

1. In the first of two experiments four sheep were fed on dried grass and oat straw in the following combination: (1)straw eaten to appetite and an equal quantity given via a rumen fistula, (2)straw eaten and grass by fistula, (3)grass eaten and straw by fistula, (4)grass eaten and grass by fistula. Mean daily dry-matter intakes (g/kg metabolic live weight, W0·75) for the four treatments respectively were: 13·3, 23·2, 47·8 and 59·4. Dry-matter digestibility coefficients (%) were 37·2, 53·1, 53·3 and 71·3. Changing the digestibility of the diet without changing the component eaten (1 v.2; 3v.4) had a large effect on intake, but changing the component eaten without changing digestibility (2v. 3) caused a twofold change in intake. The latter result implied a difference in palatability between the feeds.

2. The quantities of digesta in the rumen, determined by removal before and after feeding, were generally twice as great for treatments 3 and 4 as for 1 and 2. There were corresponding differences between treatments in the rates of passage of stained particles of feed and of chromic oxide.

3. In the second experiment the treatments were the same except that meadow hay replaced oat straw. Mean daily dry-matter intakes (g/kg W0·75) were 41·7, 55·1, 59·9 and 68·7 for treatment 1 to 4 respectively, and digestibility coefficient were 54·0, 61·3, 62·3 and 72·0. In this experiment there appeared to be only a small difference in the palatability of the feed.
The effect of the absence of rumen ciliate protozoa on growing lambs fed on a roughage–concentrate diet
Authors: Eadie J. Margaret , Gill J. C.
Published: May 2005

1. Lambs were removed form their dams at 2 d of age, and at 5 weeks of age eitht of one group were incoulated with a mixed rumen ciliate and seven in a second group were maintained ciliate-free throughout the 61 weeks of the experiment. Performance of the groups was compared when given a 2:1 roughage:concentrate diet as a set ration and withad lib.roughage.

2. Mixed ciliate populations developed in all faunated lambs and average-sized populations were maintained. Large numbers of flagellate protozoa developed in the ciliate-free animals after flagellates had been introduced into the building with the ciliate-free animals after flagellates had been introduced into the building with the ciliate inoculum.

3. Higher numbers of rumen bacteria were found in the ciliate-free group.

4. Only between the 14th and 21st weeks was there a significant different between groups in weight gain and this was infavour of the faunated group. The only significant different in body measurements was greater girth in the ciliate-free lambs.

5. Only minor differences were found between the groups in calorimetric trials, digestibility and nitrogen balanes. There were no differences between groups in concentration of total protein N and soluble sugar in the rumen. The ammonis concentration was significantly higher in the faunated group.

6. The concentrations of total rumen volatile fatty acids (VFA) were higher in the faunated group. Differences, between groups, in proportions of VFA were attributed to the activity of the rumen bacteria rather than the ciliatesper se.

7. No differences between groups were found in the concentrations of blood sugar and haemoglobin.

8. It was concluded that the changes due to the presence of rumen ciliates were not great enough to be reflected in animal performance under the conditions of this experiment.
An assessment of the nutritive value of a maize-soya mixture, ‘Soy-Ogi’, as a weaning food in Nigeria
Authors: Akinrele I. A. , Edwards Charity C. A.
Published: May 2005

1. Sour maize pap fortified with soya (Soy-Ogi), developed at the Federal Institute of Industrial Research, Oshodi, Nigeria has been evaluated chemically for its nutrient composition, biologically for protein quality and toxicity, and therapeutically on patients with kwashiorkor.

2. The indications are that it is a complete protein food suitable for feeding to children after weaning, and it compares favourably and economically with milk foods.

3. It was successfully used to restore normal health to children suffering from kwashiorkor.
Individual variation in fructose metabolism in man
Authors: Cook G. C. , Jacobson Janice
Published: May 2005

1. Constant intravenous (3 h) infusions of a fructose solution were given on a rate for body-weight basis (0·6 g/kg per h) to thirty patients who had no evidence of diabetes mellitus or liver disease. Concentrations of blood fructose, pyruvate and lactate formed a plateau during the last 1–1·5 h of the infusion period.

2. Although the numbers were small, the individual pyruvate and lactate concentrations at plateau varied greatly and assumed a bi-modal distribution, suggesting two distinct groups. The group to show a lower pyruvate and lactate rise (group A) contained more males of a lower age and more patients who had ischaemic cardiac disease than the other group (B); none of these differences was, however, statistically significant. The fructose concentrations at plateau were not significantly different between the groups. Serum triglyceride glycerol concentration during the infusions rose markedly in three patients in group A but in none in group B. Minor changes in concentration of blood glucose, insulin, inorganic phosphate and uric acid during the infusions were not significantly different between the groups and did not fall into a bi-modal pattern.

3. Constant intravenous (3 h) infusions of 0.15M-sodiurn lactate at the same infusion rate in eight of the patients (four from group A and four from group B) did not produce a significant difference in the blood lactate concentrations at plateau between patients from the two groups.

4. These results reflect qualitative differences in fructose metabolism in the patients studied. The difference in pyruvate and lactate production may be associated with total carbohydrate intake. However, the bi-modal distribution strongly suggests a genetically determined difference in metabolism between the two groups.
Hardness of human nail as an index of nutritional status: a preliminary communication
Authors: Robson J. R. K. , El-Tahawi H. D.
Published: May 2005

1. The Knoop test of hardness of materials has been used to test the hardness of human nail.

2. The range of hardness of nails was found to be small in healthy persons and large in malnourished children.

3. Nails from malnourished children were in general much harder than those from healthy persons. The nails of a small group of three children became softer while they were recovering from malnutrition.
Determination of the energy expenditure of penned and grazing sheep from estimates of carbon dioxide entry rate
Authors: Corbett J. L. , Farrell D. J. , Leng R. A. , McClymont G. L. , Young B. A.
Published: May 2005

1. NaH14CO3, was infused at a constant rate either subcutaneously or intraperitoneally into sheep kept in a uniform environment and consuming a standard amount of food each hour. After 3 h of infusion the specific radioactivity (SR) of COe obtained by acidification of samples of blood taken from the right atrium showed no significant change with time until after 22 h when the infusions were stopped.

2. Entry rates of COa (I/h) in sheep were estimated from the ratio of rate of infusion of14CO2, as NaH14C08(µCi/h) to the SR of CO2(µCi/l) in samples of jugular venous blood, urine and exhaled gas taken after infusions had been in progress for at least 3 h. Concurrently, rates of energy expenditure were calculated from the gaseous exchanges over periods of 60–90 min which were determined for grazing sheep by use of re-entrant tracheal cannulation and meter-ing and analysis of exhaled gas, or for housed sheep by measurement in respiration chambers.

3. Significant positive relationships were found between entry rate, the independent variable, and the contemporary energy expenditure. Equations obtained for grazing sheep were not significantly different from those obtained for other, housed, sheep when both groups were infused subcutaneously and COz for assay of radioactivity was obtained in all instances from blood, or in all instances from urine.

4. With subcutaneous infusion the equation relating energy expenditure to entry rate estimated from the SR of urinary COa differed significantly from that where entry rate was derived from radioactivity assays of blood or exhaled CO2. There was also a significant differ-ence between two equations where entry rates were determined from the SR of blood CO2but route of infusion was in the one instance intravenous and in the other was sub-cutaneous. Reasons for the differences between equations are discussed.

5. Changes in the rates of energy expenditure of sheep effected by intermittent exercise on a treadmill were reflected in changes in CO2entry rates. Values for the energy cost of hori-zontal locomotion by the sheep were derived from the entry rates and were similar in magni-tude to those reported by other workers.

6. I t is suggested that the method of determining energy expenditure from COz entry rate may be adapted for use on many species of animal in a variety of environments.
Nutritive value of the winged bean (Psophocarpus palustrisDesv.)
Authors: Černý K. , Kordylas Maud , Pospíšil F. , Švábenský O. , Zajíc B.
Published: May 2005

1. The winged bean (Psophocarpus palustris Desv.) has been grown successfully for several seasons, on an experimental basis, in the forest belt of Ghana, where earlier attempts to grow the soya bean had proved unsatisfactory.

2. Although botanically different, the composition of the dry seeds was found to be very similar to that of the soya bean, containing 37·3% protein, 18·1% fat, 13·9 ppm thiamin and 1·8 ppm riboflavin. The oil of the seeds contained 125·9 mg tocopherol (γ + β) per 100 g. The amino acid composition of the protein was very similar to that of the soya bean, with methionine as the first-limiting amino acid. The content of unsaturated fatty acids and that of poly-unsaturated essential fatty acids were satisfactory.

Active trypsin inhibitor found in the raw seeds could be destroyed satisfactorily by moist heat. No urease activity was detected.

The protein efficiency ratio (PER) and net protein utilization (NPU) of the beans determined with rats, were superior to those of groundnuts. The supplementary value of the protein was shown by mixing two parts of the winged bean and three parts of maize flour. When adjusted to either 10% or 16% protein, the PER values of these mixtures were similar to those of skim milk. At the 16% protein level, addition of skim milk or 0·3% DL-methionine to this mixture produced only an insignificant improvement in PER value.

The pleasant, sweet taste even when in the raw state is one of the advantages of the winged bean. Although, it is a climber, and should be staked, its cultivation on a small scale in selected areas of Ghana is recommended.
Movements of the stomach compartments of a young bull during sucking
Authors: Kay* R. N. B. , Ruckebusch Y.
Published: May 2005

1. Gastric motility was studied in a young bull and two sheep which had retained their sucking behaviour. Pressure tracings or electromyograms were recorded from all compart-ments of the stomach.

2. During the sucking of milk or water reticulum contractions either became more fre-quent but weak, or ceased altogether. After sucking, or after the introduction of fluid directly into the abomasum, reticulum contractions slowed down but retained their strength. The rumen and omasum were more fully inhibited than the reticulum.

3. It is concluded that the inhibitory response to sucking has two phases, a cephalic phase dependent upon the eagerness of sucking which mainly influences the strength of the contractions of the forestomach, and an abomasal phase dependent on the degree of distension of the abomasum which mainly affects the frequency of the contractions.
The nutrition of the veal calf
Authors: Roy J. H. B. , Stobo I. J. F. , Gaston Helen J. , Ganderton P. , Shotton Susan M. , Thompson S. Y.
Published: May 2005

1. Eighteen bull calves, comprising twelve Ayrshires, three Friesians and three Jerseys were reared from birth to a slaughter weight equivalent to 22 % of mature cow weight of the breed.

2. All the calves were given a milk substitute diet ad lib. in two feeds daily. Six of the calves received this diet alone and the remaining twelve calves were offered roughage ad lib. from I week of age, either as meadow hay or as barley straw. The calf-house was maintained at a mean temperature of 23' and a mean relative humidity of 62 %.

3. The mean total intake of meadow hay and barley straw over the experimental period of about 12 weeks was 3.0 kg and 0.4 kg respectively. Only three calves were consuming any meadow hay and only two calves any barley straw at 7 weeks of age.

4. The roughage consumed had no effect on the incidence of diarrhoea, on dry-matter intake from milk or on live-weight gain. All the calves offered meadow hay had lung lesions at slaughter. Severity of lung lesions in the Jersey and Friesian calves combined, but not in the Ayrshires, tended to be inversely related to the relative humidity to which they were exposed.

5. Dressed carcass weight and killing out percentage tended to be lower for the calves offered meadow hay. There was a highly significant inverse relationship between total intake of hay and killing out percentage. Perirenal fat depositionin relation to carcass weight was significantly lower and carotenoid content of the fat significantly higher for the calves offered the meadow hay. Skin weight per unit of slaughter weight 0.78 or carcass weight OJ* was significantly greater for the calves given the milk substitute diet only.

6. It is concluded that the calf shows very little desire to eat roughage when given a good- quality milk substitute diet ad lib. and that, even when the amounts of roughage consumed are small, this has a deleterious effect on carcass quality.
Proposal to use time spent chewing as an index of the extent to which diets for ruminants possess the physical property of fibrousness characteristic of roughages
Authors: Balch C. C.
Published: May 2005

1. Previous publications by the author and his colleagues have provided extensive records, and additional ruminating behaviour of cows receiving a wide range of diets. These recoreds, and additional unpublished records, have been used to justify a proposed index of the physical property of fibrousness, or roughage, in diets for ruminants.

2. It is proposed that the total time spent by ruminants in chewing their food, during eating and during ruminating, should be the basis of the basis of the roughage index

3. Experssion of the roughage index as total time spent chewing per kg dietary dry matter largely eliminates differences resulting from variation in the amount of food consumed, and differences resulting from the time of access to the food.

4. Examples of the proposed roughasge index are given. The values range from 145 to 191 min/Kg dry matter for oat straw ot under 20 min/kg dry matter for diets of concentrates or of finely ground herbages; hays and silages tend to fall in the region of 90–110 min/kg dry matter. Values for the indx increase with dietary proportaions of hay or straw.
The retention of ascorbic acid by guinea-pig tissues
Authors: Hughes R. E. , Hurley R. J. , Jones P. R.
Published: May 2005

1. Male and female guinea-pigs with high tissue concentrations of L-xyloascorbic acid (ascorbic acid, AA) and male guinea-pigs with high tissue concentrations of D-araboascorbic acid (isoascorbic acid, isoAA) were given a scorbutogenic diet and the rates of depletino from various tissues were measured fro both isomers.

2. The loss of AA from the brain and eye lens was considerably less rapid than the loss from the adrenal glands, spleen and aqueous humour. After 14nd on the AA-free diet the AA concentrations in the brain and eye lens were 24 and 27% respectively of the initial concentrations; the corresponding values for the aqueous humour, adrenal glands and spleen were 3,4 and 5%. There was no apparent sex difference in the rate of loss of AA.

3. The loss of isoAA was much more rapid than that of AA in the spleen, adrenal glands and aqueous humour; in the brain and eye lens the depletion patterns of the two isomers were similar.
The effect of tertiary branched-chain carboxylic acids on the energy metabolism of sheep
Authors: Clapperton J. L. , Czerkawski J. W.
Published: May 2005

1. The introduction of certain tertiary branched-chain carboxylic acids into the rumen of sheep, either by continuous infusion or by direct incorporation of the acids in the concentrate food mixture, had no effect on the oxygen consumption or carbon dioxide production of the sheep. Methane production was depressed, the extent of the depression increasing with the molecular weight of the carboxylic acid.

2. There was a small decrease in the apparent digestibility of the food and a small increase in urinary energy output.

3. There was no significant increase in the metabolizable energy intake of the sheep. There was, however, a small increase in the amount of energy stored in the body. This small increase was about 84 % of the gross energy of the branched-chain acids added.

4. It is concluded that any practical advantage to be gained from the addition of branched-chain carboxylic acids to the diet of ruminants remains unproven.
Body iron and its distribution between haem and non-haem fractions in the suckling rat
Authors: Leslie A. J. , Kaldor I.
Published: May 2005

1. Total body iron and some of its subfractions, i.e. haem iron, non-haem iron and ferritin iron, as well as ferritin were measured in groups of newborn rats and of rats aged 4,15 and 24 d.

2. Iron accumulated in the rats throughout suckling, with slightly more going into the haem than into the non-haem fraction.

3. Per unit body-weight, haem iron was maintained well throughout the study period but total body iron and non-haem iron were both significantly diminished at 15 d.

4. Within the non-haem fraction, ferritin iron was severely diminished at both 15 and 24 d, but the non-ferritin portion of non-haem iron was increased.

5. The results were interpreted in terms of the relationship between the growth of body mass and the supply of iron to the young animal.
Digestion of concentrates in sheep
Authors: Ørskov E. R. , Fraser C. , McDonald I.
Published: May 2005

1. The effect of the extent of ruminal fermentation of starch on the postruminal digestion of starch and protein was investigated in sheep, differences in rumen fermentation being obtained by giving diets based on barley, maize, or maize plus sodium chloride. The mean percentages of starch (α-linked glucose polymers) fermented in the rumen wert 91, 79 and 78 respectively with these diets, but there was considerable variability, particularly with the maize diets.

2. When large amounts of starch escaped fermentation in the rumen, substantial quantities passed the terminal ileum and were mostly fermented in the large intestine; the greatest amount of starch found in the faeces was 2 % of intake.

3. A decrease in the extent of rumen fermentation of starch was associated with a decrease in the concentration of crude protein and of diaminopimelic acid (DAPA) in the abomasal fluid, but there was no difference in quantity of crude protein disappearing from the small intestine. The concentration of DAPA was greater with the barley diet than with the maize diet, indicating that more dietary protein, originating from maize than from barley, escaped the rumen un-degraded. This conclusion was supported by a greater similarity between the amino acid composition of the abomasal fluid and the diet when maize was given.
Level of food intake and the passage of markers and nitrogen along the alimentary tract of sheep
Authors: Weller R. A. , Pilgrim A. F. , Gray F. V. , Taylor M. N. , Weller R. A. , Reid C. S. W.
Published: May 2005

1. The relative rates of passage of polyethylene glycol (PEG) and lignin through the alimentary tracts of sheep were examined through the ratio of these two markers in the fodder and in the contents of various segments of the gut. A much faster turnover of PEG than of lignin in the stomach compartments suggested that samples from these organs could not be representative of the digesta flowing through them. Average PEG:lignin ratios in the small and large intestines were close to the ratio in the fodder, indicating that sampling from the duo-denum in the living animal could possibly yield material representative of that flowing from the stomach to the small intestine. Similar results were obtained for high and low levels of fodder intake.

2. A procedure was developed for automatic sampling from the duodenum for prolonged periods, and the material collected was shown to be representative of digesta flow. Simpler methods of sampling from the duodenum were shown to be liable to relatively large errors.

3. The amount of nitrogen reaching the duodenum in sheep given lucerne hay pellets was found to be equivalent to practically 100 % of the dietary N, whether the intake of fodder was 600 g/d or 1500 g/d.
Use of the constant infusion technique for measuring rates of protein synthesis in the New Zealand White rabbit
Authors: Nicholas G. A. , Lobley G. E. , Harris C. I.
Published: May 2005

1.

To study the potential of the constant-infusion technique for measuring rates of protein synthesis in New Zealand White rabbits, animals were infused for up to 6 h with radioactively-labelled tyrosine.

2.

Labelled tyrosine from plasma and tissues was isolated from labelled metabolites by ion-exchange chromatography.

3.

Analysis of serial blood and muscle biopsy samples removed under anaesthesia showed that the specific radioactivity (SR) of the free tyrosine pools reached an approximately constant value within 2 h.

4.

Certain commercial preparations of L-[side-chain 2,3-3H]tyrosine were contaminated with 300 mg radioactive D-tyrosine/g. The D-isomer appeared to enter the muscle intracellular pool.

5.

In constant-infusion experiments L-[3H]tyrosine could replace the uniformly-14C-labelled L-isomer for the determination of rates of protein synthesis in muscle. L-[side-chain 2,3-3H]tyrosine may not be suitable for use as a precursor for measuring rates of liver protein synthesis.

6.

Evidence is presented that the precursor of liver protein synthesis may not be well defined by the SR for free tyrosine of the homogenate.

7.

The technique was used to measure the rates of protein synthesis in adult rabbits. The rates of protein synthesis in liver and muscle were measured and from measurements of tyrosine flux the mean rate of whole-body protein synthesis was calculated as 13.8 g/kg per d.
Effect of dietary protein level on some key enzymes of the tryptophan-NAD pathway
Authors: Satyanarayana U. , Narasinga Rao B. S.
Published: May 2005

1.

Six groups of rats were given diets containing protein at three levels (SO, 100 and 200 g/kg), with and without nicotinic acid. After 4 weeks on these diets some key enzymes of the tryptophan and nicotinic acid-NAD pathway, liver nicotinamide nucleotide concentration, and urinary metabolites of tryptophan and nicotinic acid were studied.

2.

Liver nicotinamide nucleotide levels were lower in rats given the diet with 50 g protein/kg as compared to those in rats given diets with 100 and 200 g protein/kg. The addition of nicotinic acid to the diet resulted in a significant increase in the levels of nicotinamide nucleotides only in rats given 50 g protein/kg diet but not in those given either 100 or 200 g protein/kg diet.

3.

Liver tryptophan oxygenase (EC1.13.1.12) activity increased with increasing dietary protein level. Nicotinic acid in the diet had no effect on its activity.

4.

Quinolinate phosphoribosyltransferase (EC2.4.2.a) activity in liver was inversely related to dietary protein level, and nicotinic acid in the diet had no effect on its activity.

5.

Liver nicotinate phosphoribosyltransferase (EC2.4.2.11) activity and kidney picolinate carboxylase (EC4.1.1.45) activity were not altered either by dietary protein level or nicotinic acid in the diet.

6.

The addition of nicotinic acid to the diet resulted in increased excretion of W-methylnicotinamide at all dietary protein levels.

7.

The inverse relationship between protein level in the diet and liver quinolinate phosphoribosyltransferase activity, the rate-limiting enzyme of the tryptophan-NAD pathway suggests that the efficiency of conversion of tryptophan to NAD is related to protein level in the diet, the efficiency decreasing with an increase in the level of dietary protein.
The effect of dietary calcium on the activity of 25-hydroxycholecalciferol-l-hydroxylase and Ca absorption in vitamin D-replete chicks
Authors: Swaminathan R. , Sommerville Barbara A. , Care A. D.
Published: May 2005

1.

As most of the studies on the regulation of renal 25-hydroxycholecalciferol-1-hydroxylase (25-HCC-1-hydroxylase) activity have been done in marginally-vitamin D-defieient animals and as it is known that vitamin D administration suppresses the specific activity of the 25-HCC-1-hydroxylase, it was decided to study the effect of dietary calcium on the activity of 25-HCC-1-hydroxylase and on Ca absorption in vitamin Dreplete chicks.

2.

Chicks, 10 d old, were given diets differing in their Ca contents (65 nmol cholecalciferol/kg diet) for 10 d and the activity of 25-HCC-1-hydroxylase in kidney homogenates, Ca absorption from the duodenum, Cabinding protein (CaBP) activity in the duodenal mucosa and plasma Ca and phosphate concentrations were all determined.

3.

The CaBP activity and the efficiency of Ca absorption both decreased with increasing dietary intake of Ca. Ca absorption and CaBP activity were significantly correlated (r0.995,P< 0.01).

4.

The activity of 25-HCC-1-hydroxylase decreased as the dietary level of Ca increased and was significantly correlated with Ca absorption (r0.900, P < 005). The plasma Ca concentration and the activity of 25-HCC-1-hydroxylase were inversely related (r-0.940,P< 0.01).

5.

It is concluded that in the vitamin D-replete chick the efficiency of duodenal Ca absorption is regulated by the renal 25-HCC-1-hydroxylase activity via production of 1,25-dihydroxycholecalciferol and CaBP synthesis.
Distribution of copper and zinc in the liver of the developing sheep foetus
Authors: Bremner I. , Williams R. B. , Young B. W.
Published: May 2005

1.

A study has been made of the copper- and zinc-binding proteins in the livers from sheep foetuses of 80-142 d gestational age.

2.

Metallothionein was found to constitute the major Zn-binding component in the cytosol at all times and to be identical to Zn-thionein from adult sheep liver.

3.

Zn also occurred in two fractions, not normally found in sheep liver, with approximate molecular weights of 28000 and 47000. The relative proportions of these were age-dependent.

4.

Between 15 and 35 % of the hepatic Cu, corresponding to most of the Cu in the cytosol, also occurred in the metallothionein-containing fraction.
The effect of dietary copper sulphate on laying performance, nutrient intake and tissue copper and iron levels of the mature, laying, domestic fowl
Authors: Jackson N.
Published: May 2005

1.

A cereal-based diet containing 16 mg copper/kg was fed ad lib. to a group of laying hens for 35 d. Five other groups were given this control diet to which was added 120, 240, 480, 960 and 1920 mg Cu/kg (as copper sulphate).

2.

Records were kept of daily food intake, water intake and egg production.

3.

After 35 d the hens were slaughtered and blood haemoglobin, packed cell volume, Cu and aspartate aminotransferase (EC2.6.1.1) levels assayed. Liver, oviduct, kidney and breast muscle Cu and iron concentrations were measured.

4.

Food and water intakes were depressed by the two highest levels of dietary Cu and water intake was increased by the diet with 240 mg added Cu/kg. Both food and water intake showed a quadratic relationship with the level of added dietary Cu.

5.

Body-weight loss was increased by the addition of Cu and showed a significant linear relationship with the concentration of added Cu in the diet. Liver and oviduct weights were depressed at the two highest levels of Cu addition.

6.

Liver and oviduct Cu and Fe concentrations were significantly increased by high dietary Cu and mean total liver and kidney Cu and Fe showed an increase although for the liver this was not statistically significant.
Determination of rumen microbial growth in vitro from32P-labelled phosphate incorporation
Authors: Van Nevel C. J. , Demeyer D. I.
Published: May 2005

1.

The extracellular phosphate pool in incubations of rumen fluid or washed cell suspensions of mixed rumen bacteria (WCS) was labelled with32P. From the constant extracellular phosphate pool specific activity and the amount of radioactivity incorporated during incubation, the amount of P incorporated in the microbial fraction was calculated. From the value for nitrogen: P determined in microbial matter, the amount of N incorporated was calculated as a measure of microbial growth.

2.

Incorporation of soluble non-protein-N in incubations devoid of substrate protein was 50 and 80 % of the values obtained using the isotope method for rumen fluid and WCS respectively. It is suggested that results obtained using the former method reflect 'net growth' of micro-organisms which is the result of simultaneous growth and degradation. The isotope method measures 'total growth', as isotope incorporation is not affected by degradation of non-growing cells.

3.

Incorporation of32P in P-containing microbial components (mainly nucleic acids) was compared with net synthesis of these components in incubations of WCS. The results showed different specific rates of synthesis and degradation for all components studied. It is concluded that the composition of microbial matter changed during growth.

4.

When N incorporation, calculated from results obtained using the isotope method in incubations with rumen fluid, was compared with the amount of carbohydrate substrate fermented and the type of fermentation, values between 18.3 and 44.6 g N incorporated/kg of organic matter fermented were obtained. Low values were associated with large proportions of the substrate being fermented to lactate and the use of glucose instead of disaccharides as substrate. Part of the variation could also be attributed to differences in incubation period, reflected in different proportions of polysaccharide formed.

5.

The use of isotopes for determination of rumen microbial growth in vitro is critically discussed.
Reasons why hypoalbuminaemia may or may not appear in protein-energy malnutrition
Authors: Coward W. A. , Whitehead R. G. , Lunn P. G.
Published: May 2005

1.

Investigations have been carried out in experimentally-malnourished rats in an attempt to explain the reasons for the development of the two main forms of protein-energy malnutrition in children, kwashiorkor and marasmus.

2.

Isoenergetic diets with values for protein: energy (P:E) of 0.21 (control diet; C) 0.032 (low-protein diet; LP) and 0.005 (very-low-protein diet; VLP) were fed to groups of twenty-six rats eitherad lib.or in restricted amounts from 5 weeks of age. Rats were killed at the start of the experiment and 1, 2 and 3 or 4 weeks later. Estimations were made of plasma albumin, insulin, corticosterone and amino acid concentrations and of the total protein content of the gastrocnemius muscles and liver.

3.

Rats given diet LPad lib.gained weight slowly and by week 1 plasma albumin concentration was slightly reduced. Rats given diet VLPad lib.gradually lost weight and plasma albumin concentrations decreased continuously.

4.

In contrast the major effect of dietary restriction during the first 2 weeks of the experiment was to maintain plasma albumin concentrations at normal values, irrespective of the diet given.

5.

At later stages, however, when the ‘restricted’ animals had become very severely wasted, albumin concentrations decreased rapidly to values approaching those found in rats given diet VLPad lib.

6.

When diets LP and VLP were givenad lib.body protein was proportionally distributed in favour of muscle rather than liver. For ‘restricted’ rats the reverse was true, at least up to the time when plasma albumin concentration began to decrease.

7.

Plasma corticosterone concentrations increased and insulin concentrations decreased when diets LP and VLP were fed in both anad lib.and a ‘restricted’ regimen but the effects were significantly greater in the latter situation.

8.

Ad lib.feeding of diets LP and VLP produced a distorted plasma amino acid pattern resembling that of kwashiorkor, but although dietary restriction resulted in a decrease in total amino acid concentration, the plasma concentration ratio, non-essential amino acids:essential amino acids was virtually unaffected.

9.

It was concluded that whilst the lower the protein concentration in the diet the greater is the extent of hypoalbuminaemia which develops, dietary restriction with an increase in plasma glucocorticoid concentration and body-wasting can initially delay the development of the hypoalbuminaemia. However, in the final stages of wasting which ensue, low plasma albumin concentrations can appear because of a failure of the mechanisms which had earlier been able to preserve them at normal levels. It is possible that these two separate and distinct routes to hypoalbuminaemia observed in this study may have parallels in human situations in developing countries.
The influence of α-linolenic acid (18: 3ω3) on the metabolism of γ-linolenic acid (18: 3ω6) in the rat
Authors: Hassam A. G.
Published: May 2005

1.

Essential fatty acid-deficient rats were fed γ-linolenic acid (18:3ω6) at 2 % dietary energy and α-linolenic acid (18:3ω3) at 0, 1.6, 2.8 and 4.0 % of the dietary energy.

2.

18:3ω3 at 1.6% apparently inhibits the synthesis of the C20 and C22 ω6 long-chain polyunsaturated fatty acids (ω6 LC-PUFA) metabolized from 18:3ω6.

3.

However, increasing the dietary levels of 18:3ω3 from 1.6 to 4.0% has no further influence.

4.

The results suggest that dietary 18:3ω6 is an efficient precursor for the ω6 LC-PUFA synthesis even in the presence of 18:3ω3.
Dry matter and nitrogen in the duodenal contents of growing pigs: a discrepancy explained
Authors: Low A. G. , Zebrowska Teresa
Published: May 2005

1.

Discrepancies between the results obtained from experiments on pigs with re-entrant duodenal cannulas have been investigated with reference to diet, cannula site and collection procedure.

2.

The results obtained from a sealed automatic collection system were different from those obtained from an open manual method and it was concluded that the maintenance of gut intra-luminal pressure in the automatic system was the causative factor.
Fractional flux rates ofNτ-methylhistidine in skin and gastrointestine: the contribution of these tissues to urinary excretion ofNτ-methylhistidine in the rat
Authors: Nishizawa N. , Noguchi T. , Hareyama S. , Funabiki R.
Published: May 2005

1.

Fractional flux rates ofNτ-methylhistidine (3-methylhistidine; Me-His) of skin and gastrointestine were measured by administering [methyl-3H]methionine to rats.

2.

The results showed that the contribution of these tissues to urinary excretion of Me-His was at least 16.6 %. This means that when fractional catabolic rates of myosin and actin were estimated from urinary excretion of Me-His, the part of Me-His derived from skin and gastrointestine should not be neglected.
Metabolic effects of a mixed and a high-carbohydrate low-fat diet in man, measured over 24 h in a respiration chamber
Authors: Hurni M. , Burnand B. , Pittet PH. , Jequier E.
Published: May 2005

1. The relation between dietary carbohydrate:lipid ratio and the fuel mixture oxidized during 24 h was investigated in eleven healthy volunteers (six females, and five males) in a respiration chamber. Values of the fuel mixture oxidized were estimated by continuous indirect calorimetry and urinary nitrogen measurements.

2. The subjects were first given a mixed diet for 7 d and spent the last 24 h of the 7 d period in a respiration chamber for continuous gas-exchange measurement. The fuels oxidized during 2·5 h of moderate exercise were also measured in the respiration chamber. After an interval of 2 weeks from the end of the mixed-diet period, the same subjects were given an isoenergetic high-carbohydrate low-fat diet for 7 d, and the same experimental regimen was repeated.

3. Dietary composition markedly influenced the fuel mixture oxidized during 24 h and this effect was still present 12 h after the last meal in the postabsorptive state. However, the diets had no influence on the substrates oxidized above resting levels during exercise. With both diets, the 24 h energy balance was slightly negative and the energy deficit was covered by lipid oxidation.

4. With the high-carbohydrate low-fat diet, the energy expenditure during sleep was found to be higher than that with the mixed diet.

5. It is concluded that: (a) the composition of the diet did not influence the fuel mixture utilized for moderate exercise, (b) the energy deficit calculated for a 24 h period was compensated by lipid oxidation irrespective of the carbohydrate content of the diet, (c) energy expenditure during sleep was found to be higher with the high-carbohydrate low-fat diet than with the mixed diet.
Effect of dietary vicine and vitamin E supplementation on the productive performance of growing and laying chickens
Authors: Muduuli David S. , Marquardt Ronald R. , Guenter Wilhelm
Published: May 2005

1. Experiments were conducted to study the effects of dietary vicine (2, 6-diamino-4, 5 dihydroxy pyrimidine-5 (β-D-glucopyranoside)) and supplemental vitamin E on the performance of laying hens and growing chicks.

2. Chicks fed on diets that contained vicine had similar growth rates but slightly higher levels of spontaneous haemolysis of erythrocytes than birds fed on a control diet.

3. Vicine when fed to laying hens had a very dramatic effect. It depressed food consumption, egg weight, fertility and hatchability of eggs, packed cell volume and erythrocyte haemoglobin levels and led to increased liver weights, liver glutathione levels, liver and plasma lipid levels, plasma lipid peroxide levels and erythrocyte haemolysis in vitro. Liver protein and plasma vitamin E:lipid levels were not altered. Vitamin E supplementation slightly increased egg weights, markedly improved fertility and hatchability of eggs and lowered liver weights and lipid levels but did not affect the other factors examined.

4. It is concluded that vicine which was isolated from faba beans (Vicia fabaL.) has a marked influence on the metabolism of the laying hen and only a slight effect on the growing chick. Vicine or its metabolites or both cause peroxidation of cellular components which result in abnormal lipid transport or synthesis or both, increased fragility of erythrocytes, and reduced fertility. These effects are overcome to varying extents by supplemental vitamin E.
Effects of dietary phosphorus and calcium on the intestinal absorption of Ca in sheep
Authors: Abdel-Hafeez H. M. , Mañas-Almendros M. , Ross R. , Care A. D. , Marshall D. H.
Published: May 2005

1. Wether sheep were used, some of which were prepared with a Thiry-Vella loop of jejunum. The long-term use of these loops was ensured by regular perfusion with fresh nutrient solution.

2. The net calcium absorption rale from a Thiry-Vella loop of jejunum increased with increasing intraluminal Ca concentration and was increased by the addition of 1 α-hydroxy-cholecalciferol (3μg/l) to the loop fluid.

3. When the diet of sheep was changed from one which was normal in Ca to a diet low in Ca there was an increase in the efficiency of net Ca absorption from the jejunal loop. This dietary change was accompanied by an increase in the circulating concentration of 1,25-dihydroxy-cholecalciferol (1.25(OH)2D3).

4. An intravenous infusion of the Ca chelating agent EDTA increased the efficiency of net Ca absorption from the jejunal loop. The use of47Ca demonstrated that this reflected an increase in the true absorption rate of Ca.

5. Dietary phosphorus deficiency reduced the efficiency of intestinal Ca absorption and was associated with a reduction in the plasma concentration of 1,25(OH)2D3.
Association of methanogenic bacteria with ovine rumen ciliates
Authors: Stumm C. K. , Gijzen H. J. , Vogels G. D.
Published: May 2005

1. The frequency of association between methanogenic bacteria and ovine rumen ciliates was studied in the rumen fluid of a fistulated sheep.

2. A period of fasting and flushing of the rumen content with nitrogen resulted in a relatively high association, whereas the intake of food and flushing with hydrogen caused a detachment of the methanogenic bacteria from the ciliates.

3. The changes in the frequency of association can be correlated with the relative attribution to the H2production by hydrogenogenic bacteria and rumen ciliates.