bluuebunny/crossref_metadata_2025 huggingface dataset:
Resting naïve CD4
+
T cells are massively infected and eliminated by X4-tropic simian–human immunodeficiency viruses in macaques
Authors: Nishimura Yoshiaki , Brown Charles R. , Mattapallil Joseph J. , Igarashi Tatsuhiko , Buckler-White Alicia , Lafont Bernard A. P. , Hirsch Vanessa M. , Roederer Mario , Martin Malcolm A.
Published: May 2005

Unlike HIV-1 and simian immunodeficiency virus (SIV), which induce a slow, unrelenting loss of immune function spanning several years, highly pathogenic simian–human immunodeficiency viruses (SHIVs) induce a rapid, complete, and irreversible depletion of CD4
+
T lymphocytes in rhesus monkeys within weeks of infection, leading to death from immunodeficiency. We recently reported that, because these SHIVs exclusively use the CXCR4 coreceptor for cell entry, they target naïve CD4
+
T cells for depletion in infected monkeys, whereas SIVs, which use CCR5, not CXCR4, cause the selective loss of memory CD4
+
T lymphocytes
in vivo
. Here we show both by DNA PCR analyses and infectivity assays, using live sorted CD4
+
T lymphocyte subsets, that 30–90% of circulating naïve cells were productively infected by day 10 after inoculation. This result implies that direct cell killing, not bystander apoptosis, is responsible for the massive loss of CD4
+
T cells in the X4-tropic SHIV model. Furthermore, we directly demonstrate that >96% of virus producing cells did not express the Ki-67 proliferation marker on day 10 after inoculation using confocal microscopic analysis of lymph nodes samples. This finding is consistent with the prodigious levels of plasma viremia measured during acute X4-tropic SHIV infections of macaques being generated almost entirely by resting naïve CD4
+
T cells.
Microbes on the human vaginal epithelium
Authors: Hyman Richard W. , Fukushima Marilyn , Diamond Lisa , Kumm Jochen , Giudice Linda C. , Davis Ronald W.
Published: May 2005

Using solely a gene-based procedure, PCR amplification of the 16S ribosomal RNA gene coupled with very deep sequencing of the amplified products, the microbes on 20 human vaginal epithelia of healthy women have been identified and quantitated. The
Lactobacillus
content on these 20 healthy vaginal epithelia was highly variable, ranging from 0% to 100%. For four subjects,
Lactobacillus
was (virtually) the only bacterium detected. However, that
Lactobacillus
was far from clonal and was a mixture of species and strains. Eight subjects presented complex mixtures of
Lactobacillus
and other microbes. The remaining eight subjects had no
Lactobacillus
. Instead,
Bifidobacterium
,
Gardnerella
,
Prevotella
,
Pseudomonas
, or
Streptococcus
predominated.
Replaceable neurons and neurodegenerative disease share depressed
UCHL1
levels
Authors: Lombardino Anthony J. , Li Xiao-Ching , Hertel Moritz , Nottebohm Fernando
Published: May 2005

Might there be systematic differences in gene expression between neurons that undergo spontaneous replacement in the adult brain and those that do not? We first explored this possibility in the high vocal center (HVC) of male zebra finches by using a combination of neuronal tracers, laser capture microdissection, and RNA profiling. HVC has two kinds of projection neurons, one of which continues to be produced and replaced in adulthood. HVC neurons of the replaceable kind showed a consistent and robust underexpression of the deubiquitination gene ubiquitin carboxyl-terminal hydrolase (
UCHL1
) that is involved with protein degradation. Singing behavior, known to increase the survival of adult-born HVC neurons in birds, significantly up-regulated the levels of
UCHL1
in the replaceable neurons but not in their equally active nonreplaceable counterparts. We then looked in the mouse brain and found relatively low
UCHL1
expression in granule neurons of the hippocampus and olfactory bulb, two well characterized types of replaceable neurons in mammals. UCHL1 dysfunction has been associated with neurodegeneration in Parkinson's, Alzheimer's, and Huntington's disease patients. In all these instances, reduced UCHL1 function may jeopardize the survival of CNS neurons.
Synergistic effects of light-emitting probes and peptides for targeting and monitoring integrin expression
Authors: Achilefu Samuel , Bloch Sharon , Markiewicz Mary A. , Zhong Tuoxiu , Ye Yunpeng , Dorshow Richard B. , Chance Britton , Liang Kexian
Published: May 2005

Integrins mediate many biological processes, including tumor-induced angiogenesis and metastasis. The arginine–glycine–aspartic acid (RGD) peptide sequence is a common recognition motif by integrins in many proteins and small peptides. While evaluating a small library of RGD peptides for imaging αVβ3integrin (ABI)-positive tumor cell line (A549) by optical methods, we discovered that conjugating a presumably inactive linear hexapeptide GRDSPK with a near-infrared carbocyanine molecular probe (Cypate) yielded a previously undescribed bioactive ligand (Cyp-GRD) that targets ABI-positive tumors. MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay with A549 cells showed that Cyp-GRD was not cytotoxic up to 100 μM in cell culture. The compound was internalized by cells, and this internalization was blocked by coincubation with a cyclic RGD peptide (cyclo[RGDfV], f isd-phenylalanine) that binds ABI with high affinity.In vivo, Cyp-GRD selectively accumulated in tumors relative to surrounding normal tissues. Blocking studies with cyclo[RGDfV] inhibited thein vivouptake of Cyp-GRD, suggesting that both compounds target the same active site of the protein. A strong correlation between the Cyp-GRD peptide and mitochondrial NADH concentration suggests that the new molecule could also report on the metabolic status of cellsex vivo. Interestingly, neither a Cypate-labeled linear RGD peptide nor an111In-labeled DOTA-GRD conjugate was selectively retained in the tumor. These results clearly demonstrate the synergistic effects of Cypate and GRD peptide for molecular recognition of integrin expression and suggest the potential of using carbocyanines as optical scaffolds for designing biologically active molecules.
The influence of the microflora of the alimentary tract on protein digestion in the chick
Authors: Salter D. N. , Coates Marie E.
Published: May 2005

1. The course of digestion of freeze-dried and heat-damaged egg albumen labelled with14C in all its constituent amino acids was compared in germ-free and conventional chicks. The albumen was given at a level of 10% in a test meal containing 28% protein. Samples of digesta were taken 5 h later and analysed for14C and nitrogenous constituents.

2. After administration of unheated albumen, 11% of the14C remained in the germ-free gut, compared with 23% in the conventional gut. The poorer digestibility of the heat-damaged albumen was shown by recovery of 42 and 47% of the14C from the gut of germ-free and conventional birds respectively.

3. With both diets there was a higher14C: nitrogen ratio in the contents of the lower gut of conventional birds. Most of the N remaining in the gut was composed of protein or the hydrolysis products of protein, the amounts of which tended to be higher in the germ-free environment; urea and uric acid formed only a small proportion of the total N. There was less urea and more uric acid in the lower gut and excreta of conventional chicks.

4. It was concluded that microbial activity did little to increase the availability of protein to the chick. However, its effect on the nitrogenous material in the lower part of the alimentary tract might result in low recovery of N in the faeces and thus lead to erroneously high estimates of protein quality in tests with conventional chicks.
Detection of early protein-calorie malnutrition (pre-kwashiorkor) in population groups
Authors: Prasanna H. A. , Desai B. L. M. , Narayana Rao M.
Published: May 2005

1. The heights and weights and the serum total protein concentration and ratio nonessential to essential amino acids (NEA:EA ratio) were determined in twenty-six Indian children, aged from 1·5 to 5 years, suffering from early protein-calorie malnutrition (pre-kwashiorkor children).

2. The heights and weights of the majority of the children approximated to 75–85% of the values for normal Indian children. The serum NEA:EA ratio of the children varied from 2·5 to 4·0. There was no correlation between this ratio and weight deficit. In healthy children of the same socio-economic group, the serum NEA:EA ratio varied from 1·5 to 2·1 with a mean of 1·7. The results show that the NEA:EA ratio may be useful as an index for the detection of pre-kwashiorkor conditions.

3. There was a significant (P< 0·05) negative correlation (r = −0·45) between serum albumin and NEA:EA ratio of the children. All the children showed consistently a significant increase in serum γ-globulin.
Copper and molybdenum in subcellular fractions of rat liver
Authors: Mills C. F. , Mitchell R. L.
Published: May 2005

1. Black-hooded weanling rats were given a copper-deficient diet or diets providing 3 ppm Cu with or without supplements containing combinations of molybdate, sulphate and sulphide salts to provide 35 ppm molybdenum and 2μg atoms sulphur/g. Changes in weight and blood haemoglobin concentration were studied during 48 d of treatment. The subcellular distribution of Cu and Mo in the liver was subsequently determined.

2. Rats fed on the Cu-deficient diet had a lower growth rate than animals receiving 3 ppm Cu and suffered a decline in blood haemoglobin concentration; Mo supplementation of the diet providing 3 ppm Cu produced similar adverse effects on growth but not on Hb. Effects of Mo on growth were exacerbated by a sulphide supplement which also decreased the rate of the gain in Hb concentration. This concentration of dietary sulphide was without effect when Mo was omitted from the diet.

3. The Cu-deficient diet decreased both the Cu concentration and proportion of total liver Cu in mitochondria + microsome and supernatant fractions of liver.

4. Mo-supplemented diets greatly increased both the Cu and Mo contents of all liver fractions. This phenomenon is considered in relation to previous suggestions that an unavailable Cu–Mo complex can form in tissues as a response to Mo accumulation.
The effect of drying and ensiling grass on its digestion in sheep
Authors: Beever D. E. , Thomson D. J. , Pfeffer E. , Armstrong D. G.
Published: May 2005

1. The effect of drying and ensiling ryegrass on the site of digestion of the energy andcarbohydrate fractions was studied in sheep fitted with rumen cannulas and re-entrant can-nulas in the proximal duodenum and terminal ileum.

2. The sheep were given fresh (frozen) grass, dried grass, wilted and unwilted silage pre-pared from herbage harvested from the same sward. The grass diets were offered twice dailyto each animal and paper impregnated with chromium sesquioxide was administered twicedaily into the rumen. Twenty-four hour collections of duodenal and ileal digesta, adjusted togive 100 yo recovery of Cr2O3, were analysed to determine the extent of digestion in the fore-stomachs, the small intestine and the caecum and colon.

3. Total digestibility of the gross energy was similar for the fresh grass, dried grass andwilted silage diets (67·4,68·1 and67·5 %)but higher for the unwilted silage (72·0 %, P < 0·01).There was an increased flow of energy into the small intestine when the sheep were given driedgrass and unwilted silage. The proportion of the apparently digested energy lost within thesmall intestine was greater when the dried grass was given (302 yo) than when the fresh grasswas given (23·6 yo).

4. Drying or ensiling of wilted material affected digestion neither in the entire alimentarytract nor in the different sections of the tract, of some carbohydrate fractions. About 97 yo ofthe digested water-soluble carbohydrate, over 90 yo of the digested cellulose and over 70 yo ofthe digested hemicellulose were digested before reaching the small intestine. The increasedamount of energy entering the duodenum of the sheep given the dried grass was notaccounted for by changes in the fate of these carbohydrate fractions in the digestive tract. Withunwilted silage, digestibilities of the cellulose and hemicellulose fractions were higher, andlower proportions of the digested carbohydrates were lost before the small intestine.
Ammonia in the large intestine of herbivores
Authors: Hecker J. F.
Published: May 2005

1. The object was toinvestigate the importance of urea a source of ammonia in the large intestine of herbivores. Urea was present in small intestinal contents of slaughtered horses in concentrations similar to those in blood but, in the small intestine of salughtered sheep, the urea was less than in blooc.

2. There was little ammonia in small intestinal contents of slaughtered horses but consider-able ammonia was present in small intestinal contents of slaughtered sheep. The ammonia in small intestinal contents of the slaughtered sheep was probably formed from urea, as ileal con-tents taken from a sheep with an ileal cannula contained considerable urea and little ammonia.

3. The ammonia concentration in caecal contents of sheep was related to the concentration of urea in blood except when ileal contents were prevented from entering the caecum.

4. Ileal digesta of sheep contained more free amino nitrogen than did caecal digesta.

5. Ammonia was absorbed more rapidly than water from the caecum of sheep. The rate of absorption was related to the concentration of ammonia in the caecum.
An attempt to estimate total body fat and protein in malnourished children
Authors: Halliday D.
Published: May 2005

1. An attempt was made to measure body volume and body fat in malnourished children using the same closed-circuit apparatus for both determinations. If these measurements were sufficiently accurate, they would enable total body protein to be calculated.

2. A helium dilution technique was used to estimate the volume of the child. Although highly reproducible measurements were obrained for the volume of inanimate objects by this techinque, the results with children were erratic.

3. The fat stores of the child were determind by measuring the amount of cyclopropane (C2H4) which would dissolve in the body. This technique gave acceptable answers with marasmic children who have little subcutaneous fat, but with obese children equilibrium could not be obtained in an acceptably short period of time. It is not practicable to calculate the equilibrium concentration by extrapolation of the uptake curve in obese children.
Growth hormone in infant malnutrition: the arginine test in marasmus and kwashiorkor
Authors: Beas F. , Contreras I. , Maccioni A. , Arenas Sara
Published: May 2005

1. Experiments in children and in animals seem to demonstrate that in marasmic malnutrition there is a reduction in the secretion of growth hormone. To study this problem the fasting, resting plasma concentrations of growth hormone were determined, before, and 45 and 60 min after, stimulation with an intravenous dose of arginine, in six infants with marasmus, in six infants with kwashiorkor and in five normal infants.

2. The values of plasma growth hormone (4·5 ± 0·97 ng/ml) in marasmic infants were significantly (P < 0·001) lower than those of the controls (7·8 ± 2·6 ng/ml), and responded little to stimulation with arginine (5·1 and 5·8 ng/ml at 45 and 60 min respectively), in contrast to those in the control group, which rose to 16·4 and 14·6 ng/ml. In children with kwashiorkor the values were very variable, but generally high, and showed little response (25·6 ± 13·3 before and 25·0 ± 17·6 and 14·2 ± 5·3 ng/ml at 45 and 60 min after stimulation respectively).

3. These results demonstrate that the responses of the hypophysis to deprivation of calories and protein (marasmus) and to protein deprivation (kwashiorkor) are different: in marasmus there is a progressive adaptation, with low secretion and poor reaction to stimulation, whereas in kwashiorkor the process is acute with high basal values of plasma growth hormone.
The distribution of copper, zinc and manganese in various regions of the brain and in other tissues of children with protein-calorie malnutrition
Authors: Lehmann B. H. , Hansen J. D. L. , Warren P. J.
Published: May 2005

1. The distribution of copper, zinc and manganese in seven regions of the brain, liver, heart, muscle from the abdominal wall, and skin of children was determined by means of atomic absorption spectrophotometry.

2. The results showed significantly lower levels of Cu, Zn and Mn in livers of children with kwashiorkor compared with control subjects. The concentrations of these three elements were higher in livers of children with marasmus than in livers of children suffering from kwashiorkor and not significantly different from those of control subjects.

3. The Cu concentration in muscle obtained from the abdominal wall of subjects with kwashiorkor and the Mn concentration in heart muscle of all groups with protein-calorie malnutrition were significantly lower than the respective values for the control group.

4. There was no significant difference between Cu, Zn or Mn concentration in brain tissues of control subjects and in those with protein-calorie malnutrition.
The measurement of exchangeable potassium in living pigs and its relation to body composition
Authors: Fuller M. F. , Houseman R. A. , Cadenhead A.
Published: May 2005

1. Twenty pigs were reared to a weight of 90 kg on various dietary regimens so that their lipid content varied from 16 to 38%;. They were injected intravenously with ~ 400 μCi of 42KCl. The animals were killed ~ 28 h after injection and their contents of water, lipid, sodium and potassium were determined.

The specific activity of plasma reached equilibrium 10–12 h after injection, that of urine not until 20 h after.

Losses of activity in urine, faeces and gut contents in the 24 h after injection amounted to 3·1, 0·3 and 1·5% of the injected dose, respectively.

Total body K was more accurately estimated from urine specific activity than from plasma specific activity.

Exchangeable K, estimated from urine specific activity Ke(u), was highly correlated with the weight of fat-free tissue (r = 0·93), the residual standard deviation of the regression being 1·8 kg fat-free tissue.

Percentage extractable fat was equally well correlated with Ke(u) (r = −0·92).
The effect of age and level of dietary calcium intake on calcium metabolism in sheep
Authors: Braithwaite G. D. , Riazuddin Sh.
Published: May 2005

1. A combination of balance and isotope techniques has been used to study the effects of age and dietary calcium content on Ca metabolism in forty-two wether sheep.

2. The amount of Ca absorbed by young growing animals varied significantly with intake. The percentage of the dietary Ca absorbed, however, remained unchanged. In older animals the amount of Ca absorbed was not altered by changes in intake, but decreased slightly with age.

3. Retention of Ca was directly related to the amount of Ca absorbed and was independent of age or breed. Furthermore, nearly all the Ca absorbed above the minimum mean amount required for maintenance was retained.

4. Faecal endogenous loss of Ca also was related to the amount of Ca absorbed. Values for faecal endogenous Ca were much lower than those used in the calculation of dietary require-ments by the Agricultural Research Council (1965).

5. Urinary Ca excretion was variable, and was not related to age or changes in dietary Ca intake.

6. Increased absorption of Ca in young growing animals was accompanied by a decreased rate of bone resorption, but the rate of bone accretion remained unchanged. Changes in dietary Ca in older animals had no effect on either of these two processes. Results indicate that bone resorption is the main pathway governing Ca homoeostasis. Both the rates of Ca accretion into bone and resorption from bone decreased with age.

7. Neither the rapidly exchangeable Ca pool (P) nor the slowly exchangeable bone pool (E) was altered by changes in dietary intake in young or mature animals. Both, however, decreased in size with age.

8. The size of the slowly exchangeable pool (E) was directly related to the rate of Ca accretion into bone. 9. The results were used to calculate dietary Ca requirements of sheep gaining weight at different rates, and these values have been compared with values recommended by the Agricultural Research Council (1965).
Plasma and blood volume studies in malnourished Iraqi children
Authors: Shakir A. , Hindawi A. Y. , El-Bedri A. L.
Published: May 2005

1. The plasma and blood volumes of twenty-eight Iraqi children were measured. Twenty-four of them were malnourished in varying degrees and four were normal children who acted as controls. None of the children was anaemic.

2. There was an increase in the plasma and blood volumes per unit body-weight correlating with the degree of malnourishment (P< 0·001).

3. There was little variation in the values for plasma and blood volumes when calculated per unit body length; the values were less constant when calculated per unit body surface.

4. The effect of age on the plasma and blood volumes per unit body-weight was less than the effect of the degree of malnutrition.

5. There was no correlation between the plasma volume of malnourished children and their corrected venous haematocrit, if children with severe anaemia were excluded.
The effects of different dietary contents of protein on amino acid and glucose production and on the contribution of amino acids to gluconeogenesis in sheep
Authors: Reilly P. E. B. , Ford E. J. H.
Published: May 2005

1. Free amino acid entry rates, rates of portal uptake of amino acids and rates of glucose synthesis from amino acids have been measured during the continuous intravenous infusion of [U-14C]-labelled mixed amino acids in six sheep receiving diets that supplied different amounts of protein.

2. In four of these sheep and in one other, total rates of glucose production have been measured using continuous intravenous infusions of [U-14C]-labelled glucose.

3. A signiiicant correlation was found between total amino acid entry rate ( Y mg/min.kg) and daily protein intake ( X g/kg):Y= 2·14+ 1·38X (r = 0·878, 0·02 > P > 0·01).

4. A significant correlation was found between the rate of absorption of amino acids into the portal system ( Y mg/min.kg) and the daily protein intake ( X g/kg):Y= 0·58 + 0·58X (r = 0·884, 0·02 > P > 0·01).

5. A highly significant correlation was found between total glucose production rates (Ymglmin. kg) and daily protein intake ( X g/kg): and daily protein intake ( X g/kg): Y = 2.14+ 1.38X (r = 0·878, 0·02 > P > 0·01).Y= 0·375f0·702X (r = 0·866, 0·005 > P > 0·001).

6. The mean proportional contribution to total amino acid entry made by portal absorption was 33·5 f 1·8 yo (six animals).

7. A significant correlation was found between the rate of glucose production from amino acids (Ymg/min.kg) and the rate of entry of amino acids ( X mg/min.kg):Y= 0-189X-0·414 ( r = 0·84, 0·01 > P > 0·005).

8. The best approximation of the proportion of glucose derived from amino acids was 28·16 f 5·1 % (six animals).

9. The specific radioactivities of amino acids in liver, kidney and muscle did not approach those found in plasma during infusions of [U-14C]-labelled mixed amino acids of up to 6·75 h.
The effects of vitamin E and training on physiological function and athletic performance in adolescent swimmers
Authors: Sharman I. M. , Down M. G. , Sen R. N.
Published: May 2005

1. Two experimental groups, each of thirteen boarding schoolboys, were given either 400 mg α-tocopheryl acetate or placeboes daily in addition to their normal diet during training in swimming and various athletic activities over a period of 6 weeks. Evaluation of the experimental treatments was made from tests of anthropometric status, cardiorespiratory efficiency and motor fitness and performance, which were administered at the beginning and end of the experimental period.

2. Whereas training significantly improved physiological function and performance in both groups (P < 0·05), vitamin E did not.
Metabolism of heat-damaged proteins in the rat
Authors: Ford J. E. , Shorrock C.
Published: May 2005

1. Freeze-dried cod muscle and casein were subjected to various conditions of heat treat-ment. Diets containing the different products, or the unheated materials, were given to a group of four adult male rats during successive 48 h periods, and urine was collected during the second 24 h of each 48 h period. A further collection of urine was made from the rats after they had been given protein isolated from heated skim-milk powder. The content and amino acid composition of the ‘peptide’ and ‘free amino acids’ in the urines were determined.

2. Heat damage to the cod-fillet protein increased the total urinary excretion of peptide-bound amino acids, from 18·6 to 48·8 µmol/rat.d. The composition of the peptide also changed, and in particular there was a marked increase in lysine, from 2·98 to 20·30 µmol %. Three amino acids - lysine, aspartic acid and glutamic acid - together comprised nearly 70 % of the total amino acid residues. There was a corresponding increase in urinary excretion of free amino acids, from 53·7 to I 14·4 µmol/rat.d. The combined losses of lysine in urinary peptide and free amino acids were 1·5 % of the total lysine ingested, as against 0·3 % for the unheated cod fillet.

3. The effects of similar heat treatment of casein on the composition of the urinary peptide and free amino acids were less marked. There was no increase in total urinary peptide excretion and there was a smaller increase in the lysine content of the peptide.

4. In urine of rats given protein isolated from heated skim-milk powder, the peptide hydro-lysate was rich in lysine and in furosine, which together comprised 41 mol % of the total amino acid composition. These compounds were presumably formed, together with a smaller quantity of pyridosine, from lysine-carbohydrate complex in the urine. It is probable that, as compared with free lysine, the lysine-carbohydrate complex was absorbed relatively in-efficiently from the rat intestine.

5. The findings are discussed in relation to the wider question of the metabolism of the ‚unavailable peptide’ that is released in the course of digestion of heat-damaged protein.
Interrelationships between riboflavin and dietary energy and protein utilization in growing chicks
Authors: Chou S. T. , Sell J. L. , Kondra P. A.
Published: May 2005

1. Reduced intake of energy or protein per se decreased riboflavin requirement of the chicks under restricted feeding regimens.

2. In severe riboflavin deficiency (2·26 mg/kg diet), efficiency of utilization of both energy and protein was decreased significantly under ad lib. conditions of feeding.

3. Efficiency of utilization of energy (but not protein) was decreased significantly in border-line riboflavin deficiency (3·02 mg/kg diet), when chicks were fed ad lib.

4. Efficiency of protein utilization was decreased significantly in severe riboflavin deficiency when chicks received an energy-restricted diet supplying 80, 70 or 60 yo of the energy intake of the controls.

5. Neither energy nor protein utilization was affected by riboflavin deficiency when both energy and protein were restricted to 70 yo of that consumed by chicks fed ad lib. However, the riboflavin deficiency produced characteristic deficiency symptoms, namely heterophilia, curled-toe paralysis, and reduction in concentration of liver riboflavin.
Evaluation of nitrogen metabolites as indices of nitrogen utilization in sheep given frozen and dry mature herbages
Authors: Egan A. R. , Kellaway R. C.
Published: May 2005

1. Twenty herbages at different stages of maturity containing from 0·77 to 5·23 g nitrogen/100 g organic matter were harvested, and green herbages were rapidly frozen and stored at - 1·5°. Each herbage was offered at levels approximating to ad lib. to a group of three sheep, individually penned. Intake, digestion and retention of N were studied during a 10 d collec-tion period after a 9 d preliminary period.

2. General regressions relating apparently digested N (NA, g/d), urinary N excretion (UN, g/d) and retention of N (NR, g/d) to N intake (NI, g/d) were established: NA= 0·88NI-3·25 (±1·14; SEb= ±O·013); UN = 2·48+0·35 NI+O·0049 NI2(±3·09; SEb1, =±0·156; SEb2= ±0·003); NR = 0·25 NI- 1·92 (±2·40; SEb= ·o·029). These equations accounted for 99% of the variability in N apparently digested, 86% of the variability in urinary N excreted, and 63 % of the variability in N retained.

3. Concentrations of ammonia and trichloroacetic-acid-precipitable N in the reticulo-ruminal digesta and of urea and a-amino-N in plasma were determined immediately before feeding, and at I and 4 h after feeding. Relationships between concentrations of metabolites in the reticulo-ruminal digesta and in plasma, and N intake, N apparently digested, urinary N output and retained N were examined. Estimates of urinary N loss and of retained N based upon metabolite concentrations at individual sampling times were characterized by high residual variabilities. Error terms were in some instances reduced significantly when both thebasal (before feeding) metabolite concentrations and the increments in metabolite concentra-tions after feeding were included in the one equation. The best relationships, based on plasma urea concentrations, accounted for only 74 % of variability in urinary N output.

4. In multiple regressions a significant portion of the variability in urinary N output and in retained N which was not accounted for by N intake could be accounted for by inclusion of metabolite values.

5. The concentration of urea in plasma was the most effective basis for prediction of N utilization. However, no prediction equation accounted for more than 90% of the total variabilityin N output, and no equation accounted for more than 71 % of the total variability in N retention. The feasibility of developing techniques for examination of efficiency of N utilization by a particular class of animal, based upon digesta and plasma metabolite con-centrations is discussed.
Nutritional aspects of amino acid metabolism
Authors: Bloxam D. L.
Published: May 2005

1. Experiments were done to find whether the rat liver can be maintained in a satisfactory condition when perfused with oxygenated Krebs-Ringer bicarbonate buffer without added protein or red cells.

2. The condition and preformance of the liver in this system were assessed from measurements made to ascertain its general condition or viability, its basal characteristics and its response to added substrates.

3. It was found that the rapid flow-rate of the medium through the livers and the efficient oxygenation of the medium ensured that enough oxygen was available for the livers to deal with large quantities of added lactate.

4. The potassium concentrations in the livers and the rates of alanine aminotransferase (EC2.6.1.6) from the cells during perfusion, and the water content after perfusion showed that the livers were not grossly damaged and that they did not deteriorate measurably for up to 3 h of perfusion.

5. Liver oxygen consumption, ATP concentrations, lactate and pyruvate concentrations and ratios, and rates of urea and glucose synthesis and bile secretion, all in perfusions without added substrate, were either similar to measurements by other workers from livers perfused withmedia containingred cells and protein or were reasonable extrapolations from availabledata.

6. The rates of glucose production from lactate, and urea and glucose output from amino acids indicated that the liver responds adequately to added substrates.

7. Measurements of amino acid concentrations in perfusate indicated that the livers of rats starved for 18–20 h regulated the amino acids to characteristic levels, by overall output or uptake, except for valine, leucine and isoleucine which were continuously given out into the medium. The results suggest that in vivo there is a general flow of most of the amino acids from extrahepatic tissues to the liver during fasting, while valine, leucine and isoleucine flow from liver to extrahepatic tissues.

8. When pentobarbitone sodium (Nembutal) was used as the anaesthetic for removal of the liver from the donor rat, the rates of urea and glucose output in perfusions without added substrates were lower than when halothane (Fluothane) was used, indicating that pentobarbitone has an inhibitory effect on these measures of liver function during the subsequent perfusion.
The effect of the type of feeding on weight gain and illnesses in infants
Authors: Dugdale A. E.
Published: May 2005

1. The effects of breast-feeding and artificial feeding have been analysed for a group 250 infants from lower socio-economic, urban families in Kuala Lumpur, Malaysia.

2. The factors considered were the ethnic group, the sex of the infant, the size and income the family and the type of milk fed. No infant in the study was given ‘non-milk’ feeds before the age of 40 weeks.

3. The effects of these factors on the weight gains and the number of reported illnesses up to the age of 40 weeks have been analysed.

4. At no time in the first 40 weeks did breast-fed infants gain weight significantly more rapidly than artificially fed infants. After the age of 20 weeks, artificially fed infants gained significantly more weight than breast-fed infants.

5. The type of feeding had no statistically significant effect on the frequency of minor respira-tory or alimentary illnesses.

6. In this community, the welfare of the family often depends on the earnings of the mother, who has to make the choice between breast-feeding and paid employment. In the group studied, breast-feeding appears to offer no advantages over artificial feeding. The principle guiding the Maternal and Child Health staff when advising the mother should be the welfare of the whole family.
The functioning of the oesophageal groove reflex and comparison of the performance of lambs fed individually and in groups
Authors: Lawlor M. J. , Hopkins S. P. , Kealy J. K.
Published: May 2005

1. Two experiments involving 106 lambs were conducted to study the functioning of the oesophageal groove reflex in lambs sucking from either individual feeders or from a bulk dispenser. The effects on the performance of lambs given either a high-protein or a low-protein creep feed in conjunction with either a ewe's milk substitute, Ewelac, or a homogenate of calcium caseinate, Casilan, were studied. Two milk substitutes, one with a long and one with a short clotting time were compared in terms of their effects on the incidence of diarrhoea.

2. The location of the liquid feeds in the stomach was studied radiologically.

3. In both experiments the sucking behaviour of the lambs was closely related to thefunctioning of the oesophageal groove reflex and performance of the lambs. In the first experi-ment the milk substitute consistently entered the abomasum in seven of the ten individually fed lambs and in twelve of the twenty-two group-fed lambs. The corresponding figures for the second experiment were twenty-two of the twenty-four individually fed and thirty-four of the fifty group-fed lambs.

4. When the milk substitute entered the abomasum it always did so throughout the fattening period even in those instances where the milk had been withheld for 1 month.

5. Poor sucking, low milk consumption and the entry of the milk into the rumen resulted in very poor performance by the lambs. Such lambs demonstrated a non-specific unthriftiness similar to the ‘tail enders’ sometimes observed with lambs reared with ewes.

6. Continued feeding with either the milk substitute or casein homogenate with a low-protein creep feed did not improve performance.

7. The clotting time of the milk substitute did not appear to influence the incidence of diarrhoea among the lambs.
Metabolic studies in rats of 75Se incorporated in vivo into fish muscle
Authors: Richold Margaret , Robinson Marion F. , Stewart R. D. H.
Published: May 2005

1.

[75Se]selenite or [75Selenomethionine was injected into the coelomic cavity of fish. After 2 d or 14 d the muscle portion of the fish was removed and homogenized. The long-term fate in rats of an oral dose of each labelled homogenate was compared with that of an oral dose of [75Se]selenite or [75Se]selenomethionine mixed with unlabelled fish homogenate.

2.

Urinary and faecal radioactivity were measured during the 1st week and whole-body radioactivity was determined for 10 weeks. Rats were killed at weekly intervals for 4 weeks for analysis of tissue distribution of 75Se.

3.

Intestinal absorption of 75Se given as labelled fish homogenate was less complete than that of 75Se mixed with unlabelled homogenate, and the absorption of 75Se from the 14d-labelled fish homogenate derived from [75Se]selenite was less complete than that of 75Se from the other labelled homogenates.

4.

Urinary excretion of absorbed 75Se in the first 7 d was in the range 5-8 % absorbed dose and was slightly greater in the rats given 75Se as selenite or derived from selenite than in those given 75Se as selenomethionine or derived from selenomethionine. Endogenous faecal excretion of absorbed Se was similar in all groups, as also were tissue distribution of retained 75Se and long-term whole-body turnover rate.

5.

The results of these studies are compared with those of earlier studies of the metabolism in rats of [75Selenomethionine, [75Se]selenite, [75Sejselenocystine and 75Se incorporated in vivo into rabbit kidney. There were differences in the initial utilization of 75Se from these various sources but after the 1st week 75Se from all sources appeared to be metabolized similarly, suggesting that for rats dietary Se of all forms is ultimately incorporated into the same metabolic pool.
Serum proteinase inhibitors and other serum proteins in protein-energy malnutrition
Authors: Schelp F. P. , Migasena P. , Pongpaew Praneet , Schreurs W. H. P. , Supawan Venus
Published: May 2005

1.

The concentrations of serum protein albumin, prealbumin and transferrin were determined in twentyeight cases of protein-energy malnutrition (PEM) with infection, together with the levels of serum proteinase inhibitors (PI), α1-antitrypsin (AT), α1-antichymotrypsin (Ach), α2-macroglobulin (α2M) and inter-α-trypsin inhibitor (IαI).

2.

Albumin, prealbumin and transferrin concentrations, as well as the levels of PI, IαI and α2M were found to be lower in cases of PEM associated with infection than the corresponding values for a group of healthy Thai preschool children and a group of newborn Thai children, but despite starvation AT and Ach values generally were increased.

3.

The results provide support for the hypothesis that PI, especially AT and Ach might limit the synthesis of albumin, prealbumin and transferrin in PEM associated with infection, via the inhibition of the mobilization of body's own protein.
Daily intakes of manganese, copper, zinc and cadmium by New Zealand women
Authors: Guthrie Barbara E. , Robinson Marion F.
Published: May 2005

1.

A total of 179 duplicate diets were collected by twenty-three women consuming their habitual diet. Twelve of the subjects were living in a residential hall for students, the others were living in their own homes or in flats. Collection periods varied from 3 to 21 d.

2.

Average daily intakes were: manganese 2.7 mg; copper 1.5 mg for diets not containing liver, 7.6 mg for fifteen diets containing liver; zinc 10.0 mg; cadmium 21μg for diets not containing liver, 27μg for fifteen diets containing liver.

3.

The intakes were compared with values for adults from other countries and with current recommended dietary allowances or estimated minimum requirements. Mn intakes were typical for non-vegetarian Western diets. Cu and Zn intakes may have been marginally low. The intakes of Cd were low.

4.

Daily intakes of protein (71 g), fat (83 g), carbohydrate (224 g) and energy (8.1 MJ) from 129 of the diets were similar to recent values obtained for New Zealand women.

5.

Subjects living in the residential hall had higher intakes of all nutrients than subjects living in their own homes or flats.
The effects of various forms of gastrointestinal cannulation on digestive measurements in sheep
Authors: MacRae J. C. , Wilson S.
Published: May 2005

1.

There was little difference in digestive (voluntary food intake, dry matter digestibility and nitrogen balance) and blood measurements (venous concentrations of corticosteroids, serum aspartate aminotransferase (EC2.6.1.1), protein-bound iodine, urea and glucose) of intact sheep (eight animals) and of sheep prepared with rumen cannulas (sixteen animals) and subsequently with either simple 'T-shaped' (eight animals) or re-entrant cannulas (eight animals) at the duodenum and ileum, when fedad lib.a chopped, medium-quality-hay ration.

2.

Wool growth rates of the intact sheep were similar to those in sheep with rumen cannulas and with rumen cannulas plus simple 'T-shaped' cannulas, but higher (P < 0-01) than those with rumen cannulas plus re-entrant cannulas.

3.

When the sheep were subsequently given a restricted intake (800 g/d) of dried grass, retention times of solid- and liquid-phase digesta markers in the rumen and caecum were similar in all sheep.

4.

The use of the different preparations in digestive physiology studies is discussed.
Polyamines and their biosynthetic decarboxylases in various tissues of the young rat during undernutrition
Authors: McAnulty P. A. , Williams J. P. G.
Published: May 2005

1.

Male weanling rats were maintained at a constant body-weight by feeding them reduced amounts of the normal diet for various periods up to 4 weeks. Control male rats were allowed free access to the normal diet and some were killed at the beginning of the experiment and others at the same ages as the experimental rats.

2.

After killing by cervical dislocation the rats had their liver, quadriceps muscles and spleen removed. The tissues were weighed and the activities of the enzymes ornithine decarboxylase (ODC; EC 4.1.1.17) and 5-adenosylmethionine decarboxylase (SAMD; EC 4.1.1.50) assayed in each tissue. In the liver the content of the polyamines (spermidine and spermine) and putrescine was also measured.

3.

The liver and quadriceps muscles showed an over-all maintenance of weight during undernutrition, but the spleen lost weight during the first 7 d of undernutrition and then remained constant. The weight of the liver increased by approximately 50 % following the daily maintenance feed, but returned to its prefeeding value by 24 h after feeding.

4.

During the first 7 d of undernutrition ODC activity decreased in all three tissues, and remained fairly constant thereafter. In the liver there were marked increases in the activity of ODC during the first 4 h after the daily feed, but the activity then decreased to prefeeding values. SAMD activity tended to remain normal in the liver, decreased initially and then returned to normal in the quadriceps muscles, and remained normal initially and then decreased in the spleen. Hepatic SAMD activity showed no consistent response to the daily feed, but quadriceps SAMD activity increased significantly between 1 and 8 h after feeding.

5.

Hepatic putrescine content remained constant during undernutrition whilst spermine increased slightly and was then maintained above normal for liver size. Hepatic spermidine content decreased initially and then remained constant. Putrescine increased slightly in response to the daily feed and spermidine increased considerably. Spermine content was unaffected by the daily feed.

6.

It is suggested that the response of polyamine synthesis in the various tissues is primarily dependent upon the way in which nutrients are made available to the tissues. The maintenance of spermine content in the liver at the expense of spermidine may be related to differential changes in the nucleic acids.
The production of renal calcinosis by magnesium deficiency in rainbow trout (Salmo gairdneri)
Authors: Cowey C. B. , Knox D. , Adron J. W. , George S. , Pirie B.
Published: May 2005

1.

Replicate groups of rainbow trout (Salmo gairdneri) were given one of five experimental diets (diets 1-5) for 16 weeks. The diets contained different amounts of calcium, phosphorus and magnesium and were prepared so that there were three levels of Ca (g/kg): 14 (diet 1), 26 (diets 2 and 3) and 40 (diets 4 and 5), Ca:P being approximately 1:1 in all diets. Diets 1, 2 and 4 had basal Mg levels (not more than 0.063 g/kg) whereas diets 3 and 5 contained supplementary Mg (1.0 g/kg).

2.

Weight gains of the trout given diets containing supplementary Mg were twice those of trout given diets with basal levels of Mg. At both dietary Mg concentrations weight gain was unaffected by the dietary Ca level.

3.

Serum Mg levels were significantly reduced in those trout given diets without supplementary Mg. The serum Ca level in those trout given the lowest concentration of Ca in their diet (14 g/kg, diet 1) was significantly greater than in those given higher amounts of Ca in their diets. Serum P levels were not significantly different with any of the experimental diets.

4.

The renal Ca concentration was increased in trout given diet 3 (26 g Ca/kg; basal Mg levels). No further increase in renal Ca concentration occurred in trout given diet 5 (40 g Ca/kg; basal Mg levels). With diets containing supplementary Mg renal Ca levels were increased at a dietary Ca level of 40 g/kg but not at a dietary Ca level of 26 g/kg. Renal Mg and P concentrations were not significantly different between any of the dietary treatments.

5.

Renal calculi were demonstrated by light and electron microscopy in tubules of those trout given diets 3 and 5 (basal Mg; 26 and 40 g Ca/kg respectively). Electron-probe micro-analysis showed that these calculi contained or comprised tricalcium phosphate.

6.

The skeletal muscle of Mg-deficient trout contained significantly more sodium than that of normal trout. It is suggested that this is indicative of an increase in extracellular fluid in the muscle of Mg-deficient trout.
Experimental protein and energy deficiencies: effects on brain free amino acid composition in rats
Authors: Kaladhar M. , Rao B. S. Narasinga
Published: May 2005

1.

The effects of protein-energy malnutrition on brain free amino acids of acidic and neutral groups were investigated in experimental rats.

2.

Severe energy restriction did not modify the free amino acid composition of the brain while protein deficiency affected certain amino acids of the brain in opposite directions. Significant decreases in the levels of aspartic acid, threonine and tyrosine were observed in the protein-deficient rats.

3.

These changes in brain amino acids appear to be specific to protein deficiency and not affected by energy deficiency.
The susceptibility of suckling lambs to zinc toxicity
Authors: Davies N. T. , Soliman H. S. , Corrigall W. , Flett A.
Published: May 2005

1.

Suckling lambs maintained for 4 weeks on a milk-substitute diet containing 407 g Toprina yeast/kg dry matter of diet exhibited poor growth, low appetite and extensive renal damage.

2.

The batch of yeast used contained 2065 mg zinc/kg.

3.

The kidneys of lambs offered a milk diet supplemented with the same Zn content as the yeast-fed diet (32.1 mg Zn/1000 kJ) were similarly affected.