bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrophysiological correlates of reward prediction error recorded in the human prefrontal cortex
Authors: Oya Hiroyuki , Adolphs Ralph , Kawasaki Hiroto , Bechara Antoine , Damasio Antonio , Howard Matthew A.
Published: June 2005

Lesion and functional imaging studies have shown that the ventromedial prefrontal cortex is critically involved in the avoidance of risky choices. However, detailed descriptions of the mechanisms that underlie the establishment of such behaviors remain elusive, due in part to the spatial and temporal limitations of available research techniques. We investigated this issue by recording directly from prefrontal depth electrodes in a rare neurosurgical patient while he performed the Iowa Gambling Task, and we concurrently measured behavioral, autonomic, and electrophysiological responses. We found a robust alpha-band component of event-related potentials that reflected the mismatch between expected outcomes and actual outcomes in the task, correlating closely with the reward-related error obtained from a reinforcement learning model of the patient's choice behavior. The finding implicates this brain region in the acquisition of choice bias by means of a continuous updating of expectations about reward and punishment.
Phenotypic knockout of VEGF-R2 and Tie-2 with an intradiabody reduces tumor growth and angiogenesisin vivo
Authors: Jendreyko Nina , Popkov Mikhail , Rader Christoph , Barbas Carlos F.
Published: June 2005

The endothelial cell receptor-tyrosine kinases, VEGF receptor 2 (VEGF-R2) and Tie-2, and their ligands, vascular endothelial growth factor (VEGF) and angiopoietins 1 and 2, respectively, play key roles in tumor angiogenesis. Several studies suggest that the VEGF receptor pathway and the Tie-2 pathway are independent and essential mediators of angiogenesis, leading to the hypothesis that simultaneous interference with both pathways should result in additive effects on tumor growth. In this study, a human melanoma xenograft model (M21) was used to analyze the effects of simultaneous intradiabody depletion of vascular endothelial growth receptor-R2 and Tie-2 on tumor angiogenesis and tumor xenograft growth. The intradiabodies were expressed from recombinant adenovirus delivered through subtumoral injection. Blockade of both VEGF-R2 and Tie-2 pathways simultaneously or the VEGF receptor pathway alone resulted in a significant inhibition of tumor growth and tumor angiogenesis (92.2% and 74.4%, respectively). In addition, immunohistochemical staining of intradiabody-treated tumors demonstrated a decreased number of tumor-associated blood vessels versus control treatment. Previous studies with intrabodies had demonstrated that the Tie-2 receptor pathway was essential for tumor growth. The simultaneous blockade of the VEGF and Tie-2 pathways resulted in effective inhibition of tumor growth and demonstrated the potential of simultaneous targeting of multiple pathways as a therapeutic strategy.
Changes in lysosomal hydrolase activity associated with malnutrition in young rats
Authors: Roobol Anne , Alleyne G. A. O
Published: May 2005

1. Total lysosomal hydrolase activities were measured in liver, gastrocnemius muscle and plasma of malnourished and normal rats between 3 and 8 weeks of age.

2. Concurrently, the DNA and protein contents of the livers and muscles were determined.

3. Increased amounts of acid hydrolase activities were found to be associated with subnormal protein: DNA ratios in the tissues of malnourished rats.

4. It was concluded that lysosomal enzymes may be involved in protein catabolism during malnutrition.
The experimental production of vitamin B12deficiency in the baboon (Papio cynocephalus). A 2-year study
Authors: Siddons R. C
Published: May 2005

1. The development of vitamin B12deficiency, as indicated by the serum and liver vitamin B12levels and the excretion of methylmalonic acid, was studied over a 2-year period in baboons (Papio cynocephalus) given a diet deficient in vitamin B12. The effects of partial hepatectomy and the inclusion of either ampicillin or sodium propionate in the diet on the rate of development of the deficiency were also studied.

2. The baboons had previously been fed on a mainly vegetarian diet. Their serum vitamin B12levels were less than 100 ng/l and the mean liver vitamin B12concentration was 0·56 μ/g. Similar serum and liver vitamin B12levels were found in baboons given a purified diet supplemented with 1 μg vitamin B12/d, and marked increases in the serum and liver vitamin B12levels occurred when the daily intake was increased to 2 μg.

3. The serum vitamin B12levels decreased to less than 20 ng/l in all baboons given a vitamin B12-deficient diet.

4. The liver vitamin B12concentration also decreased in all baboons given a deficient diet. At 9 months the lowest levels (0·20 μ/g) were found in partially hepatectomized baboons but subsequently baboons given the diet containing ampicillin had the lowest levels (0·11 μ/g).

5. The excretion of methylmalonic acid after a valine load was found to be inversely related to the liver vitamin B12concentration. In the early part of the study, partially hepatectomized baboons excreted the highest amount but subsequently baboons given a diet containing ampicillin excreted the highest amount.

6. Increased formiminoglutamic acid excretion after a histidine load was observed in two baboons given a vitamin B12-deficient diet and in both baboons the liver folic acid concentration was low.

7. No haematological or neurological symptoms of the vitamin B12deficiency were observed.
Tissue pyridoxal phosphate concentration and pyridoxaminephosphate oxidase activity in riboflavin deficiency in rats and man
Authors: Lakshmi Ambale V. , Bamji M. S
Published: May 2005

1. Parenteral administration of pyridoxal 5′-phosphate (PALP) to riboflavin-deficient rats increased the non-FAD component of erythrocyte riboflavin.

2. Pyridoxaminephosphate oxidase (EC1.4.3.5) activity in the livers of riboflavin-deficient animals was only 15% of that of controls. PALP concentration in blood, liver and brain was not affected. Deficient animals had higher levels of pyridoxine in liver.

3. Human subjects with lesions of the mouth responded to treatment with either riboflavin or pyridoxine.

4. PALP concentration of human blood was not affected by administration of riboflavin but was markedly increased by pyridoxine.

5. Erythrocyte glutathione reductase activity (EC1.6.4.2) in humans was increased andin vitrostimulation of the enzyme with FAD was decreased by treatment with riboflavin, but not by treatment with pyridoxine.
Critical evaluation of a method for estimating amino acid requirements for maintenance in the rat by measurement of the rate of14C-labelled amino acid oxidation in vivo
Authors: Neale R. J , Waterlow J. C
Published: May 2005

1. The object of the experiments was to estimate the maintenance requirements for lysine and leucine by a radioactive method. Rats were given a single dose of14C-labelled lysine or leucine and groups of animals were killed after 15, 20 and 30 d.

2. After 20 d the specific radioactivity (SR) of protein was approximately the same in liver, muscle and viscera; it was somewhat lower in skin. Once uniform SR is achieved, the rate of loss of radioactivity is a measure of the rate of endogenous loss of the amino acid.

3. The rate of loss between 20 and 30 d was measured in two ways: from the daily output of expired14CO2, and from the decrease, over the 10 d interval, of the total amount of radioactivity retained in the body.

4. For the first 15 d after administration of the labelled amino acid, all rats were given a low-protein or low-amino acid diet on which body-weight was maintained constant. For the second 15 d period some rats were kept on this diet; others were transferred either to a protein-free diet or to a diet lacking the specific amino acid (lysine or leucine) which had been administered in the labelled form.

5. The fractional rate of amino acid loss in the different experiments ranged from 1.5 to 3.5%/d, being greatest with the protein-free diet. The absolute rates of loss were calculated from measurements of the total lysine and leucine content of rats.

6. The best estimates of the rate of endogenous amino acid loss obtained in this way, expressed as mg/kg0.75per d were: lysine 136, leucine 80. These estimates are higher than most estimates of maintenance requirements obtained by growth or nitrogen balance methods and possible reasons for these discrepancies are discussed.
Hepatic copper–and zinc-binding proteins in ruminants
Authors: Bremner I , Marshall R. B
Published: May 2005

1. A metal-binding fraction with a molecular weight of about 12000 in calf and sheep liver has been characterized as a metallothionein-like protein.

2. The combined concentrations of copper and zinc in the fraction (as μg/g liver) are a direct function of liver Zn concentration.

3. The relative proportions of Cu and Zn in the fraction are dependent on the Cu: Zn ratio in the liver.

4. These findings may be relevant to the mutual interaction between Cu and Zn.
The development of the weanling rat during nutritionally - induced growth retardation and during early rehabilitation
Authors: McAnulty P. A. , Dickerson J. W. T.
Published: May 2005

1. Weanling (24-d-old) male rats were maintained at their body-weight for 1 month by restricting the intake of their normal diet. The animals were then rehabilitated for 0, 3, 7, 10 or 16 d. Control animals were given an unrestricted diet and some killed at the same body-weight as the experimental animals and others at the same age.

2. The forebrain, cerebellum, brain stem, heart, lungs, liver, spleen, kidneys, testes, and three sections of the alimentary tract were weighed, and DNA, RNA and protein contents were determined in the brain parts and liver.

3. During rehabilitation the weight of the body, corrected for the weight of the gut contents, showed a rapid gain between 7 and 10 d, which was synchronous with a rapid gain in weight of the testes.

4. The weight of the majority of organs relative to body-weight was maintained during both undernutrition and rehabilitation, the most marked exceptions being the stomach, which increased in relative weight during undernutrition, and maintained a high relative weight during rehabilitation, and the spleen, which lost weight during undernutrition, and on rehabilitation gained weight very rapidly to achieve a high relative weight.

5. The weight of the forebrain fell during undernutrition, due to a loss of water, and the weight of the brain stem rose. In the forebrain, DNA and the protein: DNA ratio were unchanged throughout, whereas a marked loss of RNA occurred during undernutrition, which was restored during rehabilitation.

6. The weight of the liver remained unchanged during undernutrition, despite increases in the amounts of DNA and protein. The amount of liver RNA decreased during undernutrition, but on rehabilitation showed an immediate and rapid increase. The variables measured in the liver were normal relative to body-weight, within 10 d of rehabilitation.

7. It is suggested that the growth occurring on rehabilitation is a balanced response to a single stimulus, partly mediated at the cellular level by RNA.
Lysozyme activity in plasma and leucocytes in malnourished children
Authors: Mohanram M. , Reddy Vinodini , Mishra S.
Published: May 2005

1. Lysozyme activity was estimated in plasma and leucocytes of twelve children suffering from kwashiorkor, thirteen children with ocular signs of vitamin A deficiency and ten apparently normal children acting as controls.

2. The results showed that the activity of lysozyme in leucocytes was significantly reduced in children with kwashiorkor and in vitamin A-deficient children. Following therapy, the levels of the enzyme in leucocytes were restored to normal.

3. The initial enzyme activity in the plasma of both groups of children did not differ significantly from the control value, and was not significantly changed after treatment.

4. It is suggested that the decreased activity of lysozyme is one of the factors responsible for diminished resistance to infection generally observed in malnourished children.
Digestion of grass lipids and pigments in the sheep rumen
Authors: Dawson R. M. C. , Hemington Norma
Published: May 2005

1. Digestion of grass lipids and pigments in the rumen of the sheep has been studied during starvation and following the administration of14C-labelled grass.

2. Both galactolipids contained in chloroplasts are rapidly degraded, although mono-galactosyldiglycerides disappear faster than digalactosyldiglycerides. It was concluded that rumen micro-organisms are mainly responsible for this degradation, although grass itself also contains enzymes which can degrade galactolipids.

3. Rumen contents can degrade added14C-labelled mono- and digalactosyldiglycerides in vitro at a rate sufficient to account for the disappearance of galactolipids in the intact rumen. The initial enzyme attack is probably a successive deacylation to give monogalactosylglycerol and digalactosylglycerol.

4. Most of the chlorophyll pigments are rapidly converted into phaeophytins by loss of magnesium. A small proportion of chlorophyllaand more of chlorophyllbremains intact even after 24 h starvation. On the other hand, about half the phaeophytin undergoes further rapid decomposition to yield phylloerythrin.

5. Although the grass phospholipids are extensively degraded, β-carotenes and many non-polar compounds, e.g. steroids, appear to undergo little change in the rumen.
A technique for measuring the biological availability of copper of sheep, sing hypocupraemic ewes
Authors: Suttle N. F.
Published: May 2005

1. Ewes were made hypocupraemic by feeding a copper-deficient diet and the subsequent responses in plasma Cu obtained when Cu was added to the diet were used to assess the biological availability of the added Cu.

2. The uniformity of responses was investigated by repleting thirty-six ewes for 33 d on two occasions with a standard diet containing 5.0 mg Cu/kg dry matter (DM). The mean responses were 0.36 and 0.33 mg/l and the coefficient of variation was approximately 53% on each occasion. The marked individual differences were largely repeatable, the correlation coefficient (r) within individuals being 0.68 (P< 0.001).

3. A dose: response relationship was investigated by giving five groups of seven ewes diets containing 2.7, 4.2, 5.7, 7.2 or 8.7 mg Cu/kg DM for 33 d. Each increment in dietary Cu above 4.2 mg/kg significantly increased the response in plasma Cu. The relationship between plasma Cu response (y, mg/l) and Cu intake (x, mg/d) after 21 d wasy= 0.0871x−0.250 (r= 0.99; 3 df).

4. The source of individual variation was investigated by comparing the responses of three ‘slow’ and three ‘fast’ responding ewes from Expt 1 to Cu given as a continuous intravenous infusion at rates of 0.05–0.3 mg/d. The relationship between plasma Cu response (y) and infusion rate (x, mg/d) after 17 d, wasy= 2.135x–0.156 (r= 0.86;P< 0 .001). The regression coefficients for ‘slow’ and ‘fast’ responding ewes were similar, as was their metabolism of intravenous64Cu, suggesting that the individual differences were due to differences in absorption rather than in the metabolism of absorbed Cu. Faecal endogenous Cu excretion was estimated to be 0.127 ± 0.019 (mean ± SE) mg/d.

5. The relative responses to oral and intravenous Cu were used to estimate the true availability of dietary Cu; in one experiment it was 4.1% and for individual ewes in another experiment, availabilities ranged from 4.5 to 11.4%. The figures are compared with assessments by conventional techniques.

6. It is concluded that the repletion technique provides a sensitive means of assessing the availability of Cu in ruminant diets.
Social interactions among adult male rats after early undernutrition
Authors: Whatson T. S. , Smart J. L. , Dobbing J.
Published: May 2005

1. Developing rats were growth-retarded during gestation and the suckling period by underfeeding their mothers from mating. After weaning, all animals were fed ad lib.

2. At 18 weeks each male was paired with another male for 10 min on 4 consecutive days. Tests 1 and 2 were with males of like-treatment group and tests 3 and 4 with males of unlike-treatment group.

3. Pairs of previously undernourished rats boxed and fought more often than pairs of controls. In the mixed pairings of tests 3 and 4 the previously underfed animals initiated contact more frequently than did their control partners.

4. Evidently there is a lasting effect of early nutritional deprivation on inter-male social behaviour, especially when both of the animals interacting are of the previously undernourished type.
The effects of acute cold exposure and feeding on volatile fatty acid metabolism in the hind leg of the young ox
Authors: Bell A. W. , Gardner J. W. , Thompson G. E.
Published: May 2005

1. Young steers were fed either 20 or 4 h before exposure to a thermoneutral or a moderately cold environment. Measurements were made of total oxygen consumption (total VO2), respiratory quotient (RQ) and hind-leg blood flow (leg Q) and oxygen uptake (leg VO2). The arteriovenous difference in plasma concentrations of individual volatile fatty acids (VFA) across the leg was also measured. Net exchange and fractional uptake of VFA by the leg were calculated from these results.

2. Cold exposure doubled total VO2, significantly decreased the RQ and caused 3-fold and 10-fold increases in leg Q and leg VO2 respectively in both 4 h- and 20 h-fed steers. Arterial plasma concentrations of total VFA (which was more than 95 % acetate) and net leg uptake of VFA also significantly increased in both groups. Cold had no effect on the fractional uptake of VFA by the leg.

3. Feeding shortly before the experiment caused a significant increase in total VO2 in thermoneutrality only, and in RQ, arterial plasma VFA and net VFA uptake by the leg in both environments. There was a significant decrease in the fractional uptake of VFA by the leg.

4. Calculations suggest that although circulating acetate could, in theory, supply over 60 % of the energy required by the hind leg in the resting, fed animal, less than 30 % of the increased requirement of the shivering leg could be supplied by acetate during acute cold exposure, even shortly after feeding.
Characteristics of skeletal muscle growth and protein turnover in a fast-growing rat strain
Authors: Bates P. C. , Millward D. J.
Published: May 2005

1. Protein turnover and muscle composition has been studied in rat skeletal muscle throughout development in a relatively-fast-growing rat strain.

2. Muscle growth involved an increase in the total DNA and in the DNA-unit size as indicated by protein: DNA. As a result of the latter increase together with no change in RNA: DNA, the RNA concentration fell throughout development.

3. Rates of protein synthesis measured in vivo by the continuous intravenous infusion method fell throughout development from 15.6%/d at 25 d to 4.46%/d at 320 d, and these changes reflected mainly the fall in RNA concentration, since there was no marked change in the rate of protein synthesis per unit RNA.

4. The rate of protein degradation, measured as the difference between rates of protein synthesis and growth, fell from 9.82%/d at 25 d to 4.46%/d at 320 d.

5. When these changes in protein turnover throughout development are compared with measurements made previously in a slow-growing strain it would appear that the faster growth was achieved as a result of increased efficiency of protein synthesis (defined as net synthesis: over-all synthesis) and this occurred mainly because of lower rate of protein degradation.
Characteristics of the rumen proteolysis of fraction I (18S) leaf protein from lucerne (Medicago sativa L)
Authors: Nugent J. H. A. , Mangan J. L.
Published: May 2005

1. The rate of proteolysis of fraction 1 (18S) leaf protein in the rumen of sheep and cattle was affected by diet and the rate on fresh lucerne (Medicago sativa L) was three to nine times the rate on a hay + concentrate diet.

2. Simultaneous rumen fermentations in vivo and in an artificial rumen showed that the rates of proteolysis of fraction I in vitro was approximately 80% of the rates in sheep.

3. Using 14C uniformly-labelled fraction I protein at low concentrations, proteolysis exhibited 1st-order kinetics. Over a wide range of protein concentrations the velocity v. substrate concentration curve showed Michaelis–Menten characteristics typical of an enzyme-catalysed reaction. With rumen fluid from a hay + concentrate-fed sheep the maximum velocity was 2.6 mg protein nitrogen/1 per min and the Michaelis constant was 75 mg nitrogen/1.

4. Rapid adsorption of 14C-labelled fraction I protein onto bacterial cells preceded proteolysis.

5. Sucrose-density-gradient analysis showed initial incorporation of 14C from protein into rumen bacteria followed by partial transfer to rumen protozoa.

6. No peptides were detected during proteoiysis showing that the rate-limiting step occurred during the initial stages of proteolysis. Only small amounts of free amino acids were released except for leucine, isoleucine, valine and ornithine, which showed significantly increased levels.

7. Volatile fatty acids were the main 14C-labelied end products and were rapidly produced in descending concentrations: acetate > propionate > 3-methyl + 2-methyl butyrate > butyrate > isobutyrate > valerate.
Utilization of amino acid analogues in diets of young turkeys
Authors: Parsons C. M. , Potter L. M.
Published: May 2005

1. The relative potencies of three lysine, one tryptophan and six methionine analogues to their corresponding L-amino acids were determined.

2. Male poults, 9 d of age, were used in five 14 d experiments. Experimental diets were formed by adding increasing levels of an amino acid (L-isomer) or its analogues to a basal diet deficient in the test amino acid. Multiple-regression analyses of body-weight gainv. level of added or amount of consumed amino acid supplement were computed. Relative potencies of the analogues were calculated using the slope-ratio technique.

3. Type of independent variable used in the regression analyses did not significantly affect relative potency values.

4. From regression analyses with level of added amino acid supplement as the independent variable, relative potencies (with 95% confidence intervals) on a molar basis of each analogue as a percentage of the respective amino acid were: hydroxymethyl-L-tryptophan monohydrate 9 (−12, 22), DL-methionine sulphone 3 (−68, 36), DL-methionine hydantoin −10 (−63, 29), L-cystine 8 (−31. 40), DL-methionine sulphoxide 59 (24, 95) and 46 (18, 74), oleoyl-DL-methionine 77 (37, 138), methionine hydroxy analogue calcium 93 (65, 128), dicocoyl-L-lysine 23 (5, 41). bis-hydroxymethyl-L-lysine-calcium 69 (54, 82) and 41 (−1, 80), mono-hydroxymethyl-L-lysine-calcium 89(77, 101) and 99(65, 134).

5. The first four analogues appeared to have little or no amino acid activity. DL-methionine sulphoxide, dicocoyl-L-lysine, and bis-hydroxymethyl-L-lysine-calcium were partially active. Relative potencies of oleoyl-DL-methionine, methionine hydroxy analogue calcium, and mono-hydroxytmethyl-L-lysine-calcium were not significantly different from those of their corresponding amino acids.
Zinc transport proteins in plasma
Authors: Chesters J. K. , Will Marie
Published: May 2005

1. Both albumin and transferrin have been suggested as carriers of zinc in plasma. Their relative importance in Zn transport was therefore investigated as a preliminary to a study of the rates of passage of Zn through plasma.

2. The apparent log stability constant for Zn binding to human apotransferrin at pH 7·4 was estimated to be approximately 5·9 which is substantially lower than previous reports of 7·0 for the corresponding value for Zn binding to albumin (Giroux & Henkin, 1972).

3. When the relative abilities of human albumin and apotransferrin to compete for Zn with low-molecular-weight chelators were compared at the same relative concentrations of these proteins as are found in plasma, albumin retained substantially more Zn than transferrin.

4. It seems likely that albumin acts as the major transport protein for Zn in plasma of most species, Zn also being present firmly bound to α2-macroglobulin.

5. In porcine plasma or serum however, there were three major Zn-binding proteins, two of which were probably albumin and α2-macroglobulin. The nature of the third component remains unknown but it appeared to have a molecular weight of between 100000–140000, it was precipitated by 2·2 M-ammonium sulphate and by 150 gpolyethylene glycol/l.

6. There were no significant differences in Zn distribution in plasma of porcine blood obtained from the aorta, the posterior vena cava or from the hepatic portal vein but use of heparin as an anticoagulant altered the normal pattern of distribution of Zn in plasma.
A vailability to pigs of amino acids in cereal grains
Authors: Taverner M. R. , Hume I. D. , Farrell D. J.
Published: May 2005

1. Endogenous levels of amino acids in ileal digests were determined as the output from pigs given protein-free diets and by extrapolation to zero intake of linear regressions of ileal amino acid outputv. dietary amino acid intake. The protein-free diets included 0 or 50 g cellulose/kg and extrapolations were made from two series of four diets which contained graded levels of wheat or barley as the only source of protein. Within each series, dietary fibre level (mg/g) was maintained at approximately 140 or 190 neutral-detergent fibre (NDF) respectively. Endogenous amino acid levels in faeces were also determined.

2. Endogenous amino acid output in faeces was linearly related to dietary fibre level; endogenous ileal output increased with dietary fibre up to approximately 100 mg NDF/g, after which endogenous output no longer increased.

3. The amino acid composition of endogenous ileal protein varied little among levels of output and among different experiments. The composition appears to be determined by the predominance of mucin protein, the slow absorption of some amino acids and the methods commonly used to measure output. The very high levels of proline and glycine in ileal digesta seemed characteristic only of protein-free and low-protein diets.

4. The amino acid composition of endogenous faecal protein also varied little among different estimates, but was considerably different from that of endogenous ileal protein. Furthermore, the similarity of bacterial and faecal proteins suggested that much of the endogenous faecal protein was of bacterial origin.
The digestion by cattle of grass silage made with formic acid and formic acid–formaldehyde
Authors: Thompson D. J. , Beever D. E. , Lonsdale C. R. , Haines M. J. , Cammell S. B. , Austin A. R.
Published: May 2005

1. A primary growth crop of perennial ryegrass (Lolium perenneL., cv. S23) was partially wilted and ensiled after the application of eitherformic acid–water (1:3, w/v; 7.1 1/t fresh herbage; control diet C) or formic acid–formaldehyde (1:1, w/w; 8·81/t fresh herbage; formaldehyde treated diet F) which supplied 50gHCHO/kg crude protein (nitrogen (N) × 6·25). The two silages were fed separately and a third diet comprising formaldehyde-treated silage, supplemented with urea (20 g/kg dry matter dm) at the time of feeding was also examined (dietFU).

2. The three diets were fed at a level of 16 g dm/kg live weight to six 3- to six-month-old cattle fitted with rumen and re-entrant duodenal cannulas in two 3 × 3 LatinSquare experiments, and measurements were made of the digestion of energy, carbohydrateand N.

3. The formaldehyde-treated silage had a lower content of fermentation acids and ammoma-N and a higher content of water-soluble carbohydrate and total amino acids. The apparent digestibility of organic matter, energy and N were depressed (P < 0·05, P < 0·05 and P < 0·01 respectively) by treatment with formaldehyde, but cellulose and neutral-detergent fibre digestibility were unaffected.

4. Within the rumen the digestion of organic matter, cellulose and neutral-detergent fibre were unaffected by formaldehyde treatment or supplementation with urea. Microbial protein synthesis in the rumen was similar for the three diets (average 131 g/kg apparently digested organic matter in the rumen).

5. The application of formic acid-formaldehyde increased (P < 0·05) the amount of food protein escaping degradation in the rumen (4·76 diet C, 6·89 diet F; 7·07 diet FU g/kg protein intake). The contribution of amino acidsof dietary origin al the duodenum increased (P < 0·05) from 50 (diet C) to 80 (diet F) and 82 (diet FU) g/kg DM intake, and the flow of total amino acids at the duodenum was 33% higher (P < 0·001) in cattle fed formic acid–form aldehyde silage diets compared withthe control silage due to the reduction in degradation of protein at ensiling and in therumen.
The digestive capacity of the caecum-colon and the value of the nitrogen absorbed from the hind gut for protein synthesis in pigs
Authors: Just A. , Jørgensen H. , Fernández J. A.
Published: May 2005

1. The aim of the investigation was to study the effects of lysine, methionine, crude protein, a complete balanced diet, maize starch and potato starch infused continuously into the caecum on the digeslibilly of the nutrients, urinary nitrogen excretion and N balance in the presence of a normal or a depressed (modified) microflora.

2. The effects of the infused nutrients on digestibility differed when diets supplemented with antibiotics were compared with unsupplemented diets.

3. Infused lysine improved the digestibility of crude protein (0·004/g lysine), crude fibre (0·01/g lysine), gross energy (0·003/g lysine) and lysine (0·03g lysine) when the diets were not supplemented with antibiotics.

Infused lysine, methionine and crude protein seemed to be of very little value for protein synthesis in the pigs, as the effects on N balance, although positive, were very small.

5. Despite the fact that a part of the infused lysine passed through the caecum-colon and into the faeces intact, the effect on N balance was negligible, indicating that the ability to absorb amino acids through the gut wall in the caecum-colon was very poor.

6. Crude protein, a complete balanced diet, maize starch and potato starch infused into the caecum were digested almost as well as if they had been given orally, thus demonstrating the large digestive capacity of the caecum-colon.
Class II phosphoinositide 3-kinase defines a novel signaling pathway in cell migration
Authors: Maffucci Tania , Cooke Frank T. , Foster Fiona M. , Traer Colin J. , Fry Michael J. , Falasca Marco
Published: June 2005

The lipid products of phosphoinositide 3-kinase (PI3K) are involved in many cellular responses such as proliferation, migration, and survival. Disregulation of PI3K-activated pathways is implicated in different diseases including cancer and diabetes. Among the three classes of PI3Ks, class I is the best characterized, whereas class II has received increasing attention only recently and the precise role of these isoforms is unclear. Similarly, the role of phosphatidylinositol-3-phosphate (PtdIns-3-P) as an intracellular second messenger is only just beginning to be appreciated. Here, we show that lysophosphatidic acid (LPA) stimulates the production of PtdIns-3-P through activation of a class II PI3K (PI3K-C2β). Both PtdIns-3-P and PI3K-C2β are involved in LPA-mediated cell migration. This study is the first identification of PtdIns-3-P and PI3K-C2β as downstream effectors in LPA signaling and demonstration of an intracellular role for a class II PI3K. Defining this novel PI3K-C2β–PtdIns-3-P signaling pathway may help clarify the process of cell migration and may shed new light on PI3K-mediated intracellular events.
Cilia and the cell cycle?
Authors: Quarmby Lynne M. , Parker Jeremy D.K.
Published: June 2005

A recent convergence of data indicating a relationship between cilia and proliferative diseases, such as polycystic kidney disease, has revived the long-standing enigma of the reciprocal regulatory relationship between cilia and the cell cycle. Multiple signaling pathways are localized to cilia in mammalian cells, and some proteins have been shown to act both in the cilium and in cell cycle regulation. Work from the unicellular alga Chlamydomonas is providing novel insights as to how cilia and the cell cycle are coordinately regulated.
Osteopontin is a hematopoietic stem cell niche component that negatively regulates stem cell pool size
Authors: Stier Sebastian , Ko Yon , Forkert Randolf , Lutz Christoph , Neuhaus Thomas , Grünewald Elisabeth , Cheng Tao , Dombkowski David , Calvi Laura M. , Rittling Susan R. , Scadden David T.
Published: June 2005

Stem cells reside in a specialized niche that regulates their abundance and fate. Components of the niche have generally been defined in terms of cells and signaling pathways. We define a role for a matrix glycoprotein, osteopontin (OPN), as a constraining factor on hematopoietic stem cells within the bone marrow microenvironment. Osteoblasts that participate in the niche produce varying amounts of OPN in response to stimulation. Using studies that combine OPN-deficient mice and exogenous OPN, we demonstrate that OPN modifies primitive hematopoietic cell number and function in a stem cell–nonautonomous manner. The OPN-null microenvironment was sufficient to increase the number of stem cells associated with increased stromal Jagged1 and Angiopoietin-1 expression and reduced primitive hematopoietic cell apoptosis. The activation of the stem cell microenvironment with parathyroid hormone induced a superphysiologic increase in stem cells in the absence of OPN. Therefore, OPN is a negative regulatory element of the stem cell niche that limits the size of the stem cell pool and may provide a mechanism for restricting excess stem cell expansion under conditions of niche stimulation.
New insights on human T cell development by quantitative T cell receptor gene rearrangement studies and gene expression profiling
Authors: Dik Willem A. , Pike-Overzet Karin , Weerkamp Floor , de Ridder Dick , de Haas Edwin F.E. , Baert Miranda R.M. , van der Spek Peter , Koster Esther E.L. , Reinders Marcel J.T. , van Dongen Jacques J.M. , Langerak Anton W. , Staal Frank J.T.
Published: June 2005

To gain more insight into initiation and regulation of T cell receptor (TCR) gene rearrangement during human T cell development, we analyzed TCR gene rearrangements by quantitative PCR analysis in nine consecutive T cell developmental stages, including CD34+ lin− cord blood cells as a reference. The same stages were used for gene expression profiling using DNA microarrays. We show that TCR loci rearrange in a highly ordered way (TCRD-TCRG-TCRB-TCRA) and that the initiating Dδ2-Dδ3 rearrangement occurs at the most immature CD34+CD38−CD1a− stage. TCRB rearrangement starts at the CD34+CD38+CD1a− stage and complete in-frame TCRB rearrangements were first detected in the immature single positive stage. TCRB rearrangement data together with the PTCRA (pTα) expression pattern show that human TCRβ-selection occurs at the CD34+CD38+CD1a+ stage. By combining the TCR rearrangement data with gene expression data, we identified candidate factors for the initiation/regulation of TCR recombination. Our data demonstrate that a number of key events occur earlier than assumed previously; therefore, human T cell development is much more similar to murine T cell development than reported before.
In situ characterization of CD4+ T cell behavior in mucosal and systemic lymphoid tissues during the induction of oral priming and tolerance
Authors: Zinselmeyer Bernd H. , Dempster John , Gurney Alison M. , Wokosin David , Miller Mark , Ho Hsiang , Millington Owain R. , Smith Karen M. , Rush Catherine M. , Parker Ian , Cahalan Michael , Brewer James M. , Garside Paul
Published: June 2005

The behavior of antigen-specific CD4+ T lymphocytes during initial exposure to antigen probably influences their decision to become primed or tolerized, but this has not been examined directly in vivo. We have therefore tracked such cells in real time, in situ during the induction of oral priming versus oral tolerance. There were marked contrasts with respect to rate and type of movement and clustering between naive T cells and those exposed to antigen in immunogenic or tolerogenic forms. However, the major difference when comparing tolerized and primed T cells was that the latter formed larger and longer-lived clusters within mucosal and peripheral lymph nodes. This is the first comparison of the behavior of antigen-specific CD4+ T cells in situ in mucosal and systemic lymphoid tissues during the induction of priming versus tolerance in a physiologically relevant model in vivo.
Ethanol Modulates the VR-1 Variant Amiloride-insensitive Salt Taste Receptor. I. Effect on TRC Volume and Na+ Flux
Authors: Lyall Vijay , Heck Gerard L. , Phan Tam-Hao T. , Mummalaneni Shobha , Malik Shahbaz A. , Vinnikova Anna K. , DeSimone John A.
Published: June 2005

The effect of ethanol on the amiloride- and benzamil (Bz)-insensitive salt taste receptor was investigated by the measurement of intracellular Na+ activity ([Na+]i) in polarized rat fungiform taste receptor cells (TRCs) using fluorescence imaging and by chorda tympani (CT) taste nerve recordings. CT responses were monitored during lingual stimulation with ethanol solutions containing NaCl or KCl. CT responses were recorded in the presence of Bz (a specific blocker of the epithelial Na+ channel [ENaC]) or the vanilloid receptor-1 (VR-1) antagonists capsazepine or SB-366791, which also block the Bz-insensitive salt taste receptor, a VR-1 variant. CT responses were recorded at 23°C or 42°C (a temperature at which the VR-1 variant salt taste receptor activity is maximally enhanced). In the absence of permeable cations, ethanol induced a transient decrease in TRC volume, and stimulating the tongue with ethanol solutions without added salt elicited only transient phasic CT responses that were insensitive to elevated temperature or SB-366791. Preshrinking TRCs in vivo with hypertonic mannitol (0.5 M) attenuated the magnitude of the phasic CT response, indicating that in the absence of mineral salts, transient phasic CT responses are related to the ethanol-induced osmotic shrinkage of TRCs. In the presence of mineral salts, ethanol increased the Bz-insensitive apical cation flux in TRCs without a change in cell volume, increased transepithelial electrical resistance across the tongue, and elicited CT responses that were similar to salt responses, consisting of both a transient phasic component and a sustained tonic component. Ethanol increased the Bz-insensitive NaCl CT response. This effect was further enhanced by elevating the temperature from 23°C to 42°C, and was blocked by SB-366791. We conclude that in the presence of mineral salts, ethanol modulates the Bz-insensitive VR-1 variant salt taste receptor.
The Frequency of Calcium Oscillations Induced by 5-HT, ACH, and KCl Determine the Contraction of Smooth Muscle Cells of Intrapulmonary Bronchioles
Authors: Perez Jose F. , Sanderson Michael J.
Published: June 2005

Increased resistance of airways or blood vessels within the lung is associated with asthma or pulmonary hypertension and results from contraction of smooth muscle cells (SMCs). To study the mechanisms regulating these contractions, we developed a mouse lung slice preparation containing bronchioles and arterioles and used phase-contrast and confocal microscopy to correlate the contractile responses with changes in [Ca2+]i of the SMCs. The airways are the focus of this study. The agonists, 5-hydroxytrypamine (5-HT) and acetylcholine (ACH) induced a concentration-dependent contraction of the airways. High concentrations of KCl induced twitching of the airway SMCs but had little effect on airway size. 5-HT and ACH induced asynchronous oscillations in [Ca2+]i that propagated as Ca2+ waves within the airway SMCs. The frequency of the Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained airway contraction. In the absence of extracellular Ca2+ or in the presence of Ni2+, the frequency of the Ca2+ oscillations declined and the airway relaxed. By contrast, KCl induced low frequency Ca2+ oscillations that were associated with SMC twitching. Each KCl-induced Ca2+ oscillation consisted of a large Ca2+ wave that was preceded by multiple localized Ca2+ transients. KCl-induced responses were resistant to neurotransmitter blockers but were abolished by Ni2+ or nifedipine and the absence of extracellular Ca2+. Caffeine abolished the contractile effects of 5-HT, ACH, and KCl. These results indicate that (a) 5-HT and ACH induce airway SMC contraction by initiating Ca2+ oscillations, (b) KCl induces Ca2+ transients and twitching by overloading and releasing Ca2+ from intracellular stores, (c) a sustained, Ni2+-sensitive, influx of Ca2+ mediates the refilling of stores to maintain Ca2+ oscillations and, in turn, SMC contraction, and (d) the magnitude of sustained airway SMC contraction is regulated by the frequency of Ca2+ oscillations.
The Contraction of Smooth Muscle Cells of Intrapulmonary Arterioles Is Determined by the Frequency of Ca2+ Oscillations Induced by 5-HT and KCl
Authors: Perez Jose F. , Sanderson Michael J.
Published: June 2005

Increased resistance of the small blood vessels within the lungs is associated with pulmonary hypertension and results from a decrease in size induced by the contraction of their smooth muscle cells (SMCs). To study the mechanisms that regulate the contraction of intrapulmonary arteriole SMCs, the contractile and Ca2+ responses of the arteriole SMCs to 5-hydroxytrypamine (5-HT) and KCl were observed with phase-contrast and scanning confocal microscopy in thin lung slices cut from mouse lungs stiffened with agarose and gelatin. 5-HT induced a concentration-dependent contraction of the arterioles. Increasing concentrations of extracellular KCl induced transient contractions in the SMCs and a reduction in the arteriole luminal size. 5-HT induced oscillations in [Ca2+]i within the SMCs, and the frequency of these Ca2+ oscillations was dependent on the agonist concentration and correlated with the extent of sustained arteriole contraction. By contrast, KCl induced Ca2+ oscillations that occurred with low frequencies and were preceded by small, localized transient Ca2+ events. The 5-HT–induced Ca2+ oscillations and contractions occurred in the absence of extracellular Ca2+ and were resistant to Ni2+ and nifedipine but were abolished by caffeine. KCl-induced Ca2+ oscillations and contractions were abolished by the absence of extracellular Ca2+ and the presence of Ni2+, nifedipine, and caffeine. Arteriole contraction was induced or abolished by a 5-HT2–specific agonist or antagonist, respectively. These results indicate that 5-HT, acting via 5-HT2 receptors, induces arteriole contraction by initiating Ca2+ oscillations and that KCl induces contraction via Ca2+ transients resulting from the overfilling of internal Ca2+ stores. We hypothesize that the magnitude of the sustained intrapulmonary SMC contraction is determined by the frequency of Ca2+ oscillations and also by the relaxation rate of the SMC.
Phosphorylation of Phosphoprotein Enriched in Astrocytes (PEA-15) Regulates Extracellular Signal-regulated Kinase-dependent Transcription and Cell Proliferation
Authors: Krueger Joseph , Chou Fan-Li , Glading Angela , Schaefer Erik , Ginsberg Mark H.
Published: May 2005

Cell cycle progression is dependent on the nuclear localization and transcriptional effects of activated extracellular signal-regulated kinase (ERK)1 and ERK2 mitogen-activated protein (MAP) kinases (ERK1/2). Phosphoprotein enriched in astrocytes (PEA-15) binds ERK1/2 and inhibits their nuclear localization, thus blocking cell proliferation. Here, we report that phosphorylation of PEA-15 blocks its interaction with ERK1/2 in vitro and in vivo and that phosphorylation of both Ser104and Ser116is required for this effect. Using phosphomimetic and nonphosphorylatable mutants of PEA-15, we found that PEA-15 phosphorylation abrogates its capacity to block the nuclear localization and transcriptional activities of ERK1/2; this phosphorylation therefore enables the proliferation of cells that express high levels of PEA-15. Additionally, we report that PEA-15 phosphorylation can modulate nontranscriptional activities of ERK1/2, such as the modulation of the affinity of integrin adhesion receptors. Finally, we used a novel anti-phospho-specific PEA-15 antibody to establish that PEA-15 is phosphorylated in situ in normal mammary epithelium. These results define a novel posttranslational mechanism for controlling the subcellular localization of ERK1/2 and for specifying the output of MAP kinase signaling.
Inhibition of the Transforming Growth Factor β (TGFβ) Pathway by Interleukin-1β Is Mediated through TGFβ-activated Kinase 1 Phosphorylation of SMAD3
Authors: Benus Germaine F.J.D. , Wierenga Albertus T.J. , de Gorter David J.J. , Schuringa Jan Jacob , van Bennekum Ariëtte M. , Drenth-Diephuis Loes , Vellenga Edo , Eggen Bart J.L.
Published: May 2005

Transforming growth factor β is the prototype of a large family of secreted factors that regulate multiple biological processes. In the immune system, TGFβ acts as an anti-inflammatory and immunosuppressive molecule, whereas the cytokine interleukin (IL)-1β is a crucial mediator of inflammatory responses and induces proinflammatory genes and acute phase proteins. Here, we present evidence for the existence of a direct inhibitory interaction between the IL-1β and TGFβ signaling cascades that is not dependent on IL-1β–induced SMAD7 expression. IL-1β and its downstream mediator TAK1 inhibit SMAD3-mediated TGFβ target gene activation, whereas SMAD3 nuclear translocation and DNA binding in response to TGFβ are not affected. IL-1β transiently induces association between TAK1 and the MAD homology 2 domain of SMAD3, resulting in SMAD3 phosphorylation. Furthermore, IL-1β alleviates the inhibitory effect of TGFβ on in vitro hematopoietic myeloid colony formation. In conclusion, our data provide evidence for the existence of a direct inhibitory effect of the IL-1β-TAK1 pathway on SMAD3-mediated TGFβ signaling, resulting in reduced TGFβ target gene activation and restored proliferation of hematopoietic progenitors.
Lowe Syndrome Protein OCRL1 Interacts with Clathrin and Regulates Protein Trafficking between Endosomes and the Trans-Golgi Network
Authors: Choudhury Rawshan , Diao Aipo , Zhang Fang , Eisenberg Evan , Saint-Pol Agnes , Williams Catrin , Konstantakopoulos Athanasios , Lucocq John , Johannes Ludger , Rabouille Catherine , Greene Lois E. , Lowe Martin
Published: May 2005

Oculocerebrorenal syndrome of Lowe is caused by mutation of OCRL1, a phosphatidylinositol 4,5-bisphosphate 5-phosphatase localized at the Golgi apparatus. The cellular role of OCRL1 is unknown, and consequently the mechanism by which loss of OCRL1 function leads to disease is ill defined. Here, we show that OCRL1 is associated with clathrin-coated transport intermediates operating between the trans-Golgi network (TGN) and endosomes. OCRL1 interacts directly with clathrin heavy chain and promotes clathrin assembly in vitro. Interaction with clathrin is not, however, required for membrane association of OCRL1. Overexpression of OCRL1 results in redistribution of clathrin and the cation-independent mannose 6-phosphate receptor (CI-MPR) to enlarged endosomal structures that are defective in retrograde trafficking to the TGN. Depletion of cellular OCRL1 also causes partial redistribution of a CI-MPR reporter to early endosomes. These findings suggest a role for OCRL1 in clathrin-mediated trafficking of proteins from endosomes to the TGN and that defects in this pathway might contribute to the Lowe syndrome phenotype.