bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional capacity of adipose tissue in human obesity and hyperlipidaemia
Authors: Tremolieres J , Sautier CL , Carre L , Flament CL , Plumas B
Published: May 2005

1. Fifteen ‘constitutionally’ obese subjects, eleven hyperlipidaemic subjects of mixed-type and fourteen normal subjects were studied.

2. With a reduction in energy intake (range 3.3–4.2 MJ) for 21 d, there was no change in the levels of plasma total cholesterol (TC) and triglyceride (TG) of obese subjects, but the free fatty acid levels increased. However, in hyperlipidaemic subjects there was a reduction in levels of TC and TG with no increase in levels of free fatty acids.

3. There was a significant increase in the serum ketone levels of obese subjects but not in those of hyperlipidaemic subjects. The reduction of the respiratory quotient to a value of 0.7 was more rapid in the obese than in hyperlipidaemic subjects.

4. After administration of a fat load (0.5 g/kg gross body-weight) there was no change in plasma TG levels in obese subjects but there was an increase in those of normal subjects.

5. After administration of a glucose load (1 g/kg ideal body-weight) there was a significant reduction in plasma TG levels in obese subjects but no change in those of hyperlipidaemic subjects.

6. Hyperlipidaemic subjects eating their normal diet were found to have a hydroxybutyrate: acetoacetate ratio three- to fivefold that of obese and normal subjects.

7. These results suggest that obese subjects have an increased ability to store fatty acids, to mobilize them quickly and to generate fatty acid metabolites in the form of ketone bodies, while these same metabolic functions are reduced in hyperlipidaemic subjects.
Hepatic copper–and zinc-binding proteins in ruminants
Authors: Bremner I , Marshall R. B
Published: May 2005

1. A study has been made by gel-filtration techniques of the soluble copper- and zinc-binding proteins in livers from calves and sheep of widely differing Cu and Zn status.

2. Cu and Zn generally occurred together in three main fractions, with approximate molecular weights of > 75000, 35000 and 12000, and Zn also in one other fraction with molecular weight about 65000. The distribution of the metals between these fractions was variable and dependent on both the Cu and Zn status of the animals.

3. Zn was usually absent from the low-molecular-weight fraction in Zn-deficient or high-Cu livers, with Cu also being absent in the former instance.

4. The fraction with molecular weight of 35000 was tentatively identified as hepatocuprein. It generally accounted for only 4% of the total hepatic Cu except in Cu-deficient livers.

5. The possible relationship of these findings to the mutual antagonism between Cu and Zn is discussed.
The nutritive value of dried red clover as a supplement for perennial ryegrass hay
Authors: Mosley G.
Published: May 2005

1. A low-digestibility ryegrass hay was fed to sheep and the effect of supplementation with dried red clover on animal production and digestion was examined. Comparisons were made using other supplements containing (a) barley (isoenergetic with clover supplement), (b) barley and decorticated groundnut meal (isoenergetic and isonitrogenous with clover supplement), (c) barley, groundnut meal and mineral salts (containing an equivalent level of digestible energy, apparently digestible crude protein and minerals to those of the clover supplement).

2. Dry matter intake, digestibility of organic matter and live-weight gain were higher with clover supplemented hay than with hay alone, and the live-weight gain response to clover supplementation was comparable with the concentrate diet (supplement c), which supplied an equivalent level of digestible energy, crude protein and minerals.

3. The utilization of digestible energy for live-weight gain was significantly higher (P < 0.05) for clover than for hay, hay plus barley, and hay plus barley and groundnut meal. The utilization of the clover – hay mixture was similar to that of the hay plus concentrates and minerals and tended to be higher than that of the concentrate diet without minerals, although the difference was not significant (P < 0.05).

4. There was no significant difference between hay and clover diets in the proportions of volatile fatty acids found in the rumen, although there was a shift from acetate to butyrate production with the two diets containing groundnut meal.

5. The apparent digestibility of nitrogen for both hay and clover was low, but intake and retention was markedly increased with clover.

6. The intake and retention for all the minerals studied was better for the clover-supplemented hay and all-clover diets than for the hay diet, and the availability of sodium, potassium, magnesium, calcium and phosphorus was higher. The availability and retention of Na, K and Mg with the clover-supplemented hay diet were slightly lower than the mineral-supplemented diet, while those of Ca and P were higher.
Passage of protozoa and volatile fatty acids from the rumen of the sheep and from a continuous in vitro fermentation system
Authors: Weller R. A. , Pilgrim A. F.
Published: May 2005

1. A procedure for sampling digesta from within the omasal canal of sheep given a variety of roughage diets was used to enable comparison to be made of the composition of effluent from the reticulo-rumen with that of rumen fluid.

2. Concentrations of protozoa in effluents, relative to a soluble marker continuously infused intraruminally, were usually less than 20% of corresponding rumen fluid concentrations. It was estimated that the amount of protozoal nitrogen leaving the rumen represented less than 2% of dietary N.

3. Passage of volatile fatty acids (VFA) from the rumen in effluent was less than 75% of that indicated by rumen concentrations.

4. A continuous, in vitro fermentation system was developed, in which outputs of protozoa were comparable with in vivo outputs.
The rate of adaptation of urea cycle enzymes, aminotransferases and glutamic dehydrogenase to changes in dietary protein intake
Authors: Das T. K. , Waterlow J. C.
Published: May 2005

1. Measurements were made, at 6 h intervals, of urinary nitrogen output and of the activity of some hepatic enzymes in the rat during adaptation from one level of dietary protein to another. The enzymes measured were arginase (EC3.5.3.1), argininosuccinate lyase (EC4.3.2.1), argininosuccinate synthetase (EC6.3.4.5), glutamate dehydrogenase (EC1.4.1.2) and alanine and aspartate aminotransferases (EC2.6.1.2 andEC2.6.1.1).

2. Completeness of urine collection, which was essential for these experiments, was checked by recovery of injected [131I]iodide.

3. When the dietary protein content was reduced from 135 to 45 g casein/kg, the urinary N output and the activities of the hepatic enzymes reached their new steady-state levels in 30 h. The reverse adaptation, from 45 to 135 g casein/kg, was also complete in 30 h.

4. The rate of change of enzyme activity and the final activity as percentage of initial activity were very similar for all six enzymes, suggesting a common control mechanism. The calculated half-lives of the enzymes were of the order of 7 h, which is very much shorter than those found by previous workers.

5. There was no simple relationship between the activity of the urea cycle enzymes and the amount of N excreted. When an equal amount of gelatin was substituted for casein the N output was doubled but there was no change in the activity of the liver enzymes.

6. The results suggest that the activity of the urea cycle enzymes depends in part on the amount of N available for excretion after the demands for synthesis have been met. The enzymes, however, appear to be present in excess so that an increased N load was not necessarily accompanied by an increase in enzyme activity.
Effects of the amount and type of food eaten on secretion from fundic abomasal pouches of sheep
Authors: McLeay L. M. , Titchen D. A.
Published: May 2005

1. The effects on gastric secretion of altering the amount and type of food eaten were examined in sheep with fundic abomasal pouches and in sheep which also had the antral region of the abomasum isolated into a pouch or removed (antrectomy). Secretion, which was continuous in all preparations, was collected over 24 h periods, and daily determinations of its acid and pepsin concentrations were made for periods of up to 10 weeks.

2. Experimental diets consisting of chaffed lucerne, meadow and wheaten hays were fed onad lib. or restricted regimens.

3. Raising and lowering the dry matter (DM) intakes of lucerne chaff increased and decreased respectively the volume, acidity and acid and pepsin outputs (volume x concentration of acid or pepsin) of fundic pouch secretion.

4. Increases of 27–64% in the amount of lucerne chaff eaten, after changing from restricted toad lib. feeding, were followed by increases in the volume (19–66%), acid concentration (4–10 mequiv. H+/l, 3–9%) and acid output (18–76%) of pouch secretion.

5. With DM intakes of mixed lucerne and wheaten chaffs between 88 and 107% of those of lucerne, the secretion from the pouches was reduced to 45–88% of the volume and 39–77% of the acid output observed with the lucerne diet. Acid concentration was least affected, being unchanged in one series of observations and decreased by, at the most, 13 mequiv. H+/l (12%) in another. Reverting to a diet of lucerne chaff reversed these effects: the volume was increased by 30–49%, acid concentration by 2–15 mequiv. H+/l (2–14%), acid output by 38–68% and pepsin output by 30–43% although the intake of DM was the same or 6% less than that on the wheaten chaff mixture.

6. Secretion was greater when animals ate lucerne chaff than when they ate meadow chaff.

7. The changes in secretion according to diet were obtained in animals with antral pouches and antrectomy as well as in those with only fundic pouches.

8. It is argued in discussion that the markedly different abomasal secretions on different diets arise from abomasal stimulation due to the nature rather than the amount of digesta entering it and that although the pyloric antrum contributes to these changes it is not essential for their occurrence.
Hardness of finger nails in well-nourished and malnourished populations
Authors: Robson J. R. K.
Published: May 2005

1. The Knoop test of hardness applied to samples of finger nails from 334 healthy and 147 malnourished individuals showed statistically significant differences in the mean hardness of the nails of the two groups.

2. The hardest nails were those of Filipino infants and children suffering from protein-energy deficiency. The softest nails were those of children in Guatemala recovering from protein-energy deficiency. Ranking of hardness appeared to be related to the severity and duration of protein-energy depletion.

3. In children up to 12 years of age, hardness did not appear to be influenced by the age, sex, and racial origins of individuals or the environmental conditions to which nail specimens were exposed.

4. Further studies are required to correlate hardness with clinical, biochemical and anthropometric measurements of nutritional status during protein-energy deprivation and during recovery. The causes of the differences in hardness need to be explored.
The relationship between serum urea levels and dietary nitrogen utilization in young men
Authors: Taylor Yvonne S. M. , Scrimshaw N. S. , Young V. R.
Published: May 2005

1. Results from metabolic balance studies in young adult men were examined for the relationships between the concentration of serum urea (SUN) and the efficiency of dietary nitrogen utilization. A total of 231 separate balance periods were included in the analysis. Net protein utilization (NPU) was used as an index of dietary protein quality.

2. Protein intake ranged from 0·27–0·73 g/kg body-weight per d in the various experiments. There was a highly significant negative correlation between NPU and urea levels. The relationship was: NPU = 1·23–0·029 × SUN (mmol/l) (r = −0·89).

3. These results are considered in relation to the evaluation of protein quality in adult humans.
Concentrations of amino acids and urea in the plasma of the ruminating calf and estimation of the amino acid requirements
Authors: Williams A. P. , Smith R. H.
Published: May 2005

1. A study was made of factors affecting the plasma concentrations of free amino acids (PAA) and urea (PU) in calves receiving approximately equal daily amounts of concentrates (flaked maize and protein supplements) and straw, the former at 10.00 and 17.00 hours, the latter at 17.00 hours only.

2. For calves receiving a diet containing 20 g nitrogen/kg dry matter in which the protein supplement was decorticated, extracted groundnut meal (DCGM) (diet A) there were marked increases in PAA and PU about 1–2 h after a morning feed, then a fall in these values 2 h later to a level which was maintained for the next 3 h. No similar changes occurred after the evening feed. Samples taken 3 h after the morning feed were used in subsequent comparative experiments. There was much more variation between animals than within animals in total PAA, PU and the concentrations of most individual amino acids in these samples.

3. Total PAA and most individual amino acid concentrations were not appreciably affected when the DCGM intake was reduced to give 10 g N/kg dry matter in the diet (diet C), but PU was halved. When maize gluten replaced DCGM as the protein supplement at the higher N intake (diet B) then PU doubled, but again total PAA and most individual amino acid concentrations were little affected. Exceptions were arginine, which was halved, and leucine, which was doubled.

4. Infusions of more than 4·4 g L-methionine/d into the abomasums of calves (110–160 kg live weight) receiving diet A led to a marked increase in plasma methionine concentration. This was considered to correspond with the point at which methionine requirements were met. Using a chromic oxide marker to estimate flows of methionine and cystine from the rumen to the duodenum, it was calculated that under these conditions the methionine requirement was 9·8 g/d, with a cystine flow of 4·9 g/d. Similar calculations showed the corresponding value to be 7·5 g/d with a cystine flow of 2·8 g/d for calves receiving diet C.

5. Infusion of increasing levels of L-lysine into the abomasums of calves (110–160 kg live weight) receiving diet B led to a progressive increase in plasma lysine concentration. There was no consistent change in the rate of increase with increasing amounts infused. Estimated lysine requirement appeared therefore to be less than the flow of lysine from the rumen to the duodenum under these conditions (18·8 g/d).
The subcellular distribution of copper, zinc and iron in liver and kidney. Changes during copper deficiency in the rat
Authors: Alfaro Begoña , Heaton F. W.
Published: May 2005

1. The subcellular distribution of copper, zinc and iron was investigated in liver and kidney homogenates from Cu-deficient and control rats. The supernatant fraction contained most Cu and Zn in control animals, but the highest proportion of Fe was in the microsomal fraction.

2. Cu deficiency reduced the concentration of the metal in all fractions, but the depletion was most severe and developed most rapidly in the supernatant fraction, indicating that the soluble cytoplasm is the site of Cu storage in the cell. The Fe content of the liver increased during Cu deficiency with Fe being deposited preferentially in the mitochondria.

3. All the Cu and most of the Zn in liver and kidney supernatant fractions occurred in four protein-containing fractions that were of similar molecular weights in both organs. A fraction of molecular weight 30000 was primarily concerned with Cu storage in mature rats.

4. The reduction in liver Zn during Cu deficiency appeared to be the result of impaired intestinal absorption and it is suggested that a small amount of Cu facilitates the absorption of Zn.
Dietary fibre and sterol metabolism in the rat
Authors: Morgan B. , Heald Monique , Atkin Sandra D. , Green J. , Chain E. B.
Published: May 2005

1. Sterol metabolism was studied in rats fed on a semi-synthetic fibre-free diet and in rats fed on diets containing cellulose (200 or 100 g/kg) or sugar-cane fibre (bagasse) at the same levels.

2. Rats fed on the diets containing cellulose or bagasse produced significantly greater quantities of faeces than did rats fed on the fibre-free diet.

3. Rats given bagasse excreted more bile acid and more neutral sterol in their faeces than did rats fed on cellulose or on the fibre-free diet.

4. After 28 d, hepatic synthesis of cholesterol (from acetate) and cholesterol 7α-hydroxylase activity were significantly higher in animals fed on bagasse than in animals fed on the other two diets.

5. No significant differences in serum cholesterol levels were seen in rats fed on any of the three diets.

6. Food consumption was not substantially altered by the inclusion of bagasse or cellulose in the diets, although the efficiency of foodstuff utilization was generally lower.

7. Bagasse adsorbed substantial quantities of cholic acid in vitro, whereas cellulose did not. The lignin fraction prepared from bagasse contributed only slightly to the total bile acid-binding capacity of bagasse.

8. The results are discussed in the light of possible effects of dietary fibre on sterol metabolism in man.
Collagen metabolism in folic acid deficiency
Authors: Hautvast J. G. A. J. , Barnes M. J.
Published: May 2005

1. The effect of folic acid deficiency on collagen formation, with respect to the level of collagen-protein synthesis and the extent of collagen-proline hydroxylation, has been studied. A folic acid-free diet containing 10 g sulphasuxidine/kg was used to induce folate deficiency in young male rats. Animals were judged folic acid-deficient on the grounds of retardation of growth, characteristic haematological changes and the urinary excretion of formimino-L-glutamic acid.

2. From isotope incorporation studies it was found that folic acid deficiency caused a marked impairment in collagen synthesis. It was shown, however, from the use of pair-fed control animals, that this was due in part to a reduced food intake accompanying the vitamin deficiency. The further reduction in synthesis in addition to that attributable to inanition was considered to arise from an involvement of folic acid in general protein synthesis, since it was found that the synthesis of elastin and non-collagenous skin proteins was similarly impaired.

3. Reduced synthesis of collagen was not considered attributable to lack of hydroxylation of peptidyl proline that may occur in ascorbic acid deficiency. Hydroxylation of collagen- and elastin-proline was only very slightly impaired in folic acid deficiency. It was concluded that, at least when ascorbic acid is present, folic acid is not directly essential for the hydroxylation, in vivo, of peptidyl proline. The results support the view that ascorbic acid participates direct, in vivo, in this hydroxylation rather than indirect by simply maintaining an adequate level of reduced folates. They do not, however, exclude the possibility, arising from the known ability of tetrahydrofolate to participate in the hydroxylation of collagen proline in vitro, that when both ascorbate and folate are present, the latter may, in some measure, share in the role of reducing agent in the hydroxylation of peptidyl proline in vivo.
Hydrolysis of the phytate of wheat flour during breadmaking
Authors: Daniels D. G. H. , Fisher N.
Published: May 2005

1. Differences in the extent of breakdown of phytate in wholemeal and white flours prepared from three wheats when the flours were made into bread using the three main UK commercial breadmaking processes were investigated.

2. The extent of breakdown (31–46% for wholemeal breads, 88–99% for white breads) was not proportional to the relative processing times involved (1–4 h). The importance of destruction of phytate in the oven is stressed.

3. The phytase (myo-inositol hexaphosphate phosphohydrolase.EC3.1.3.8) activities of the wholemeal flours and of the yeast were determined. Re-examination of some information in the literature enabled the relative importance of these activities, and of the various stages of breadmaking, in determining the extent of hydrolysis of phytate to be assessed.

4. Average values for the molar ratio, phytate: zinc, of 22:1 and 0.8:1 were calculated for wholemeal and white breads respectively. The nutritional significance of these results is discussed.
Zinc absorption in the rat
Authors: Jackson M. J. , Jones D. A. , Edwards R. H. T.
Published: May 2005

1. A method of studying zinc absorption in rats has been developed in which binding of radioactive Zn to the intestinal mucosa and absorption into the carcass was determined at different times after administration by stomach tube.

2. This technique has been used to evaluate different hypotheses concerning the control of Zn absorption and to examine the processes by which this occurs.

3. The proportion of radioactive Zn absorbed into the carcass was found to be dependent on the Zn status of the animals but that found within the small intestinal wall was independent of this, indicating the existence of two mechanisms of Zn absorption.

4. One of these two mechanisms has been shown to be induced by a low dietary Zn content while the other was shown to be insensitive to this. This latter mechanism predominated in rats of normal dietary Zn status and a study of the characteristics of this process indicated that the quantity of Zn absorbed was proportional to the dietary Zn content over the normal range of intake. This implies that normally Zn homeostasis in rats is achieved through variations in Zn excretion. The additional mechanism of Zn absorption only becomes fully active at levels of dietary Zn below 0.24 μmol/g diet.
A possible control of food intake during pregnancy in the rat
Authors: Morgan Brian , Winick Myron
Published: May 2005

1. Brain hypothalamic concentrations of serotonin and norepinephrine have been implicated in the control of food intake. During pregnancy and lactation a rat dam's food consumption is increased and so a study was performed to ascertain whether this was associated with changes in the hypothalamic content of serotonin and norepinephrine.

2. In the first experiment, forty-eight Sprague Dawley rat dams were given a diet containing 250 g casein/kg adlib. After 2 weeks, eight were killed and their hypothalamic analysed for the previously-mentioned neurotransmitters. The rest were mated and continued on the diet. On each of days 7, 14 and 20 of gestation, day 14 of lactation and 2 weeks after weaning of their pups a further eight dams were killed and their hypothalami assayed as described previously. Food intake was monitored throughout the experimental period.

3. The increased food intake of the dams during gestation and lactation increased to the same extent as elevations in hypothalamic norepinephrine content and depressions in serotonin content. After lactation food intake returned to pre-pregnancy levels as did the hypothalamic levels of norepinephrine and serotonin.

4. By using the same experimental design but limiting the increase in food intake in pregnancy and lactation to half the expected amount the same changes were found in hypothalamic norepinephrine and serotonin contents.

5. The possibility of hypothalamic neurotransmitter contents controlling food intake is discussed.
Digestion in the pig between 7 and 35 d of age 6. The digestion of hydrolyzed milk and soya-bean proteins
Authors: Leibholz Jane
Published: May 2005

1. Four pelleted diets were prepared containing milk or isolated soya-bean protein (ISP) as the major protein source. The milk and ISP were given either as intact proteins or partially (0·65) hydrolyzed with papain before feeding.

2. The diets were given ad lib. to thirty-two pigs from 7–28 d of age. The pigs were slaughtered at 28 d of age.

3. Weight gains, food conversion ratios and nitrogen balances of pigs given diets containing milk protein were better than those of diets containing ISP (231 g/d, 0·80 and 11·5 g/d compared to 209 g/d, 0·88 and 9·00 g/d respectively)

4. Partial hydrolysis of proteins before feeding did not affect the performance of the pigs.

5. Apparent digestibilities of N before the ileum and in the whole tract were 0·78 and 0.94 for the pigs given the ISP diets and 0·86 and 0·97 for the pigs given the milk-protein diets.

6. Retention time of ISP diets in the whole digestive tract was 1475 min and that of the milk-protein diets was 1089min.

7. pH of digesta in the stomach was 5·0–5·3 for all diets and increased to 6·9–7.1 in the ileum.

8. There were no differences in flows of total N and protein N to the ileum and lower digestive tract between the pigs given the intact- and hydrolyzed-protein diets.

9. Apparent absorptions of N in the stomach, duodenum and jejenum were greater in the pigs given diets containing hydrolyzed proteins than in those given diets containing the intact proteins.

10. Flows of total N and protein N to the ileum tract were greater when the pigs were given the ISP diets than when they were given the milk-protein diets.

11. Hydrolysis of proteins before feeding resulted in a reduced trypsin and chymotrypsin activity in the duodenum and pancreas.

12. Retention of dietary N in the carcass was greater in pigs given the milk-protein diets (0·79) than in those given the ISP diets (0·68).
An attempt to distinguish between the direct and indirect effects, in the laying domestic fowl, of added dietary copper sulphate
Authors: Stevenson Mary H. , Jackson N.
Published: May 2005

1. An experiment is reported in which the effects of giving copper sulphate-supplemented diets and control unsupplemented pair-fed diets to laying hens were compared.

2. The level of food intake significantly adversely affected mean body-weight, egg number, egg weight, liver, kidney, oviduct and ovary weights. Gizzard weight/kg body-weight was significantly increased both with decreasing levels of food intake and increased CuSO4supplementation.

3. There was evidence of a depressing effect of CuSO4per seon egg production and possibly on oviduct and ovary weight.

4. Liver lipid concentration was significantly decreased with decreasing levels of food intake and the results also suggest a depressing effect of CuSO4.

5. The Cu concentrations and total contents in liver and kidneys were significantly increased by dietary added CuSO4. Liver and kidney Zn and Fe concentrations were increased with decreasing levels of food intake rather than by CuSO4. addition.
Utilization of free lysine by growing pigs
Authors: Batterham E. S. , Murison R. D.
Published: May 2005

1. The results of nine estimates of the efficiency of utilization of supplements of free lysine by growing pigs fed once daily and reported by Batterham (1974) and Batterham & O'Neill (1978) were re-analysed using carcass rather than live-weight values as the criteria of response.

2. The efficiency of utilization of free lysine with once daily feeding relative to frequent feeding was 0·53 using carcass gain as the criterion of response (P < 0·001), and 0·56 using food conversion efficiency on a carcass basis (P < 0·001). These estimates were lower than estimates of 0·67 using live-weight gain (P < 0·01) and 0·77 using food conversion ratio on a live-weight basis (P < 0·05).

3. The results indicate that current estimates of the lysine requirements of pigs that are based on responses to supplements of free lysine under once daily feeding regimens may be 10–30% over-estimated, as a result of incomplete utilization of the free lysine.
Essential fatty acid deficiency and evidence for arachidonate synthesis in the cat
Authors: Sinclair A. J. , Slattery W. , McLean J. G. , Monger E. A.
Published: May 2005

1. There is controversy regarding the capacity of the cat to convert 18:2ω6 to 20:4ω6 and the ability of the essential fatty acid (EFA)-deficient cat to produce 20:3ω9.

2. This paper reports the isolation and identification of 20: 3ω9 from kidney phospholipids of EFA-deficient cats.

3. The results suggest that the cat is capable of limited synthesis of 20:4ω6 using a Δ5- and Δ8-desaturase.
Acetate supply and utilization by the tissues of sheep in vivo
Authors: Pethick D. W. , Lindsay D. B. , Barker P. J. , Northrop A. J.
Published: May 2005

1. The supply and utilisation of acetate has been estimated simultaneously in the whole animal and tissues of sheep using a combination of isotope-dilution and arteriovenous-difference techniques. Animals were made alloxandiabetic and acetate metabolism was compared when stabilized to normal metabolite levels with insulin (ITA sheep) and when food and insulin had been withdrawn for 36 h (fasted, diabetic sheep).

2. Acetate was simultaneously produced and utilized by all tissues. The exogenous (or gut) supply of acetate was the most important determinant of circulating acetate level. Endogenous acetate was produced mainly in the liver; 77 and 94% in fasted, diabetic and ITA sheep respectively. The production of endogenous acetate remained fairly constant and was not related to ketogenesis, which supports the idea that circulating acetate is largely a product of fermentation. The liver, gut and muscle utilized 17, 25 and 54% respectively (96% total) of the acetate entry rate in ITA sheep; a similar percentage utilization was found in fasted, diabetic sheep.

3. Acetate is largely oxidized to carbon dioxide in the gut and muscles of sheep and may account for 30–40% of their oxidative metabolism. This figure is similar to that for the whole animal. The total acetate taken up by the liver could account for 30% of the oxygen consumption; however, the liver may not directly oxidize all the utilized acetate.

4. The over-all conclusion from this study is that acetate is largely of dietary origin and the major factor determining its rate of utilization is the arterial concentration.
Measurement of zinc flux through plasma in normal and endotoxin-stressed pigs and the effects of Zn supplementation during stress
Authors: Chesters J. K. , Will Marie
Published: May 2005

1. The rates of transport of zinc through plasma have been investigated in normal and endotoxin-stressed pigs.

2.65Zn added to porcine plasma in vitro rapidly equilibrated with the Zn originally present.

3.65Zn bound to albumin and injected intravascularly into pigs rapidly equilibrated with two kinetically distinguishable pools. The first of these pools was mainly associated with the plasma but was significantly larger than the plasma volume and substantially so in Zn-deficient pigs. The second pool appeared to represent a summation of the rapidly-exchangeable Zn within the extravascular tissues.

4. In non-stressed animals, the flux of Zn from the plasma of Zn-deficient pigs was only half that in Zn-supplemented animals.

5. Administration of endotoxin reduced the plasma Zn concentration of Zn-supplemented pigs but not of Zn-deficient animals. The fractional turnover rates of Zn were not altered in either of the two pools following endotoxin.

6. At 10 h after giving endotoxin neither the Zn content of the two pools nor the flux of Zn through them differed significantly between Zn-deficient and control pigs.

7. Intravascular infusion of Zn at a rate which essentially prevented the usual depression in plasma Zn concentration following endotoxin failed to alleviate the effects of endotoxin on Zn-supplemented pigs.

8. The reduction in plasma Zn concentration following endotoxin stress appears to be a normal physiological response which is not indicative of an increased metabolic requirement for Zn.
Effect of monensin on the fermentation of basal rations in the Rumen Simulation Technique (Rusitec)
Authors: Wallace R. J. , Czerkawski J. W. , Breckenridge Grace
Published: May 2005

1. A long-term experiment was made with the Rumen Simulation Technique (Rusitec), in which the fermentation of a mixed ration of hay (1Og/d) and bruised barley (5g/d) was compared with the fermentation of the same diet in the presence of 2, 10 and 50 mg monensin/d.

2. Monensin depressed the production of acetic and butyric acids, markedly increased the production of propionic acid and virtually eliminated the production of isovaleric acid. The production of methane was decreased in the presence of monensin, but this decrease could be accounted for entirely by the changes in the production of volatile fatty acids and redistribution of metabolic hydrogen.

3. The digestibility of dry matter (DM) in the rations declined in the presence of monensin. Determinations of the rates of digestion showed that the digestion of the readily-fermented food in the initial stages was not affected by monensin, but that at 24 h digestion had been inhibited by monensin. The inhibition was due entirely to its effect on the digestion of the fibrous components. Digestion of non-fibrous material was not affected.

4. The efficiency of microbial growth, expressed as g dry weight/mol ATP formed (YATP) and in terms of dm digested, tended to be increased by monensin. This however occurred only at high, non-practical doses.

5. Urease (EC3.5.1.5) was induced by the addition of urea to the fermentation, but monensin had no effect on urease activity. Although monensin increased the activity of protease in washed suspensions, more food protein apparently escaped degradation. This may have been due to decreased deaminative activity.

6. Monensin altered the mircroscopic appearance of the fermentation fluid, and changed the activity of some enzymes in sonicated extracts, including alkaline phosphatase (EC3.1.3.1), acetate kinase (EC2.7.2.1) and succinate dehydrogenase (EC1.3.9.1). These results are discussed in terms of known sensitivities of rumen microbes to monensin and their contribution to the fermentation as a whole.
Availability to pigs of amino acids in cereal grains
Authors: Taverner M. R. , Hume I. D. , Farrell D. J.
Published: May 2005

1. Pigs prepared with re-entrant ileal cannulas were used to determine the ileal availability of amino acids in nine cereal grains including five wheats, sorghum (Sorghum vulgare Pers.), maize, barley and Triticale.

2. The average true availability of amino acids in these grains was 0·88 but there were consistent differences in availability among amino acids. Generally, lysine and threonine were among the least available amino acids while glutamic acid and arginine were among the most available amino acids in cereal protein.

3. There was as much variation in amino acid availability within a grain species (wheat) as among the other grains.
Availability to pigs of amino acids in cereal grains
Authors: Taverner M. R. , Farrell D. J.
Published: May 2005

1. Availability values for amino acids in nine cereal grains determined by faecal analyses with pigs and by the Silcock available lysine test (Roachet al.1967) and an in vitro digestibility assay were compared with ileal availability values for the same grains determined with pigs by Taverneret al.(1981b).

2. There was a significant canonical correlation of ileal and faecal availability values. On average, apparent faecal availability of the indispensable amino acids was 4·2% greater than apparent ileal availability, but the difference was up to 12·6% for threonine. Furthermore, the difference appeared to increase as the digestibility of the grain decreased.

3. Silcock available-lysine values for the cereal grains were unrelated to the lysine truly absorbed by the pig.

4. There were close relationships of ileal protein and lysine availability values on nitrogen digestibility determined by an in vitro assay using pronase enzyme.
Availability to pigs of amino acids in cereal grains
Authors: Taverner M. R. , Farrell D. J.
Published: May 2005

1. Protein digestibility and lysine availability were determined in a range of grain samples using an in vitro digestibility assay calibrated with ileal digestibility values.

2. Mean(± SE) values predicted for nitrogen digestibility were 0·92±0·011 in wheat and 0·88±0·021 in barley, and the predicted lysine availability in wheat was 0·86±0·021.

3. Chemical and physical characteristics of the grains were determined and those most closely associated with protein digestibility for wheat were the contents of hemicellulose, neutral-detergent fibre, the bulk density, and to a lesser extent, N and acid-detergent fibre contents. These relationships were used to determine prediction equations for the available lysine content of wheat.
Doxorubicin Requires the Sequential Activation of Caspase-2, Protein Kinase Cδ, and c-Jun NH2-terminal Kinase to Induce Apoptosis
Authors: Panaretakis Theocharis , Laane Edward , Pokrovskaja Katja , Björklund Ann-Charlotte , Moustakas Aristidis , Zhivotovsky Boris , Heyman Mats , Shoshan Maria C. , Grandér Dan
Published: May 2005

Here, we identified caspase-2, protein kinase C (PKC)δ, and c-Jun NH2-terminal kinase (JNK) as key components of the doxorubicin-induced apoptotic cascade. Using cells stably transfected with an antisense construct for caspase-2 (AS2) as well as a chemical caspase-2 inhibitor, we demonstrate that caspase-2 is required in doxorubicin-induced apoptosis. We also identified PKCδ as a novel caspase-2 substrate. PKCδ was cleaved/activated in a caspase-2–dependent manner after doxorubicin treatment both in cells and in vitro. PKCδ is furthermore required for efficient doxorubicin-induced apoptosis because its chemical inhibition as well as adenoviral expression of a kinase dead (KD) mutant of PKCδ severely attenuated doxorubicin-induced apoptosis. Furthermore, PKCδ and JNK inhibition show that PKCδ lies upstream of JNK in doxorubicin-induced death. Jnk-deficient mouse embryo fibroblasts (MEFs) were highly resistant to doxorubicin compared with wild type (WT), as were WT Jurkat cells treated with SP600125, further supporting the importance of JNK in doxorubicin-induced apoptosis. Chemical inhibitors for PKCδ and JNK do not synergize and do not function in doxorubicin-treated AS2 cells. Caspase-2, PKCδ, and JNK were furthermore implicated in doxorubicin-induced apoptosis of primary acute lymphoblastic leukemia blasts. The data thus support a sequential model involving caspase-2, PKCδ, and JNK signaling in response to doxorubicin, leading to the activation of Bak and execution of apoptosis.
Trypanosoma cruziPosttranscriptionally Up-Regulates and Exploits Cellular FLIP for Inhibition of Death-inducing Signal
Authors: Hashimoto Muneaki , Nakajima-Shimada Junko , Aoki Takashi
Published: May 2005

Intracellular persistence of the protozoan parasite, Trypanosoma cruzi, is an aggravating cause of Chagas' disease, involving that the protozoan infection specifically inhibits death receptor-mediated apoptosis of host cells. Here we demonstrate that the parasite dramatically up-regulates cellular FLICE inhibitory protein (c-FLIP), the only known mammalian inhibitor specific for death receptor signaling, in infected cells by an unusual, posttranscriptional stabilization of the short-lived protein. We also show that c-FLIP is accumulated in T. cruzi–infected mouse heart muscle cells in vivo. Stimulation of death receptor Fas in infected cells induces recruitment of c-FLIP to block the procaspase-8 activation at the most upstream caspase cascade. c-FLIP knock-down with a small interfering RNA significantly restores Fas-mediated apoptosis in infected cells. Taken together, our findings indicate that T. cruzi posttranscriptionally up-regulates and exploits host c-FLIP for the inhibition of death-inducing signal, a mechanism that may allow parasites to persist in host cells.
DYRK1A Enhances the Mitogen-activated Protein Kinase Cascade in PC12 Cells by Forming a Complex with Ras, B-Raf, and MEK1
Authors: Kelly Paul A. , Rahmani Zohra
Published: May 2005

Dual-specificity tyrosine-phosphorylated and regulated kinase 1A (Dyrk1A) is the human homologue of the Drosophila mnb (minibrain) gene. In Drosophila, mnb is involved in postembryonic neurogenesis. In human, DYRK1A maps within the Down syndrome critical region of chromosome 21 and is overexpressed in Down syndrome embryonic brain. Despite its potential involvement in the neurobiological alterations observed in Down syndrome patients, the biological functions of the serine/threonine kinase DYRK1A have not been identified yet. Here, we report that DYRK1A overexpression potentiates nerve growth factor (NGF)-mediated PC12 neuronal differentiation by up-regulating the Ras/MAP kinase signaling pathway independently of its kinase activity. Furthermore, we show that DYRK1A prolongs the kinetics of ERK activation by interacting with Ras, B-Raf, and MEK1 to facilitate the formation of a Ras/B-Raf/MEK1 multiprotein complex. These data indicate that DYRK1A may play a critical role in Ras-dependent transducing signals that are required for promoting or maintaining neuronal differentiation and suggest that overexpression of DYRK1A may contribute to the neurological abnormalities observed in Down syndrome patients.
Stat3 Is Required for Full Neoplastic Transformation by the Simian Virus 40 Large Tumor Antigen
Authors: Vultur Adina , Arulanandam Rozanne , Turkson James , Niu Guilian , Jove Richard , Raptis Leda
Published: May 2005

To investigate the role of Stat3 (signal transducer and activator of transcription-3) in neoplastic transformation by the Large Tumor antigen of Simian Virus 40 (TAg), murine fibroblasts were rendered deficient in Stat3 activity through expression of a Stat3-specific siRNA or a Cre-loxP recombination system. The results demonstrate that growth rate, formation of foci overgrowing a monolayer of normal cells and colony formation in soft agar were dramatically reduced in Stat3-deficient cells. In addition, TAg expression led to increased Stat3 tyrosine phosphorylation, DNA binding, and transcriptional activity, suggesting that Stat3 is required for TAg-mediated neoplasia. Stat3 activation was prevented by blocking the binding of TAg to pRb (retinoblastoma-susceptibility gene product), whereas genetic ablation of pRb increased Stat3 activity, suggesting that pRb inactivation by TAg might be responsible for the observed Stat3 activation. Stat3 activation by TAg was suppressed after inhibition of c-Src, JAKs or the insulin-like growth factor receptor. On the other hand, targeted disruption of the Fer kinase or pharmacological inhibition of Abl had no effect. Inhibition of Src activity led to Stat3 down-regulation as well as apoptosis of sparsely growing, TAg-transformed cells. However, Src inhibition was relatively ineffective in confluent cells, consistent with previous results indicating that cell to cell adhesion activates Stat3 by a Src-independent mechanism. Direct Stat3 inhibition on the other hand induced apoptosis very effectively in confluent cells, which could have significant therapeutic implications. Taken together, our results suggest that Stat3 is an important component of a pathway emanating from TAg and leading to neoplastic conversion.
Actin Filament Bundles inDrosophilaWing Hairs: Hairs and Bristles Use Different Strategies for Assembly
Authors: Guild Gregory M. , Connelly Patricia S. , Ruggiero Linda , Vranich Kelly A. , Tilney Lewis G.
Published: May 2005

Actin filament bundles can shape cellular extensions into dramatically different forms. We examined cytoskeleton formation during wing hair morphogenesis using both confocal and electron microscopy. Hairs elongate with linear kinetics (∼1 μm/h) over the course of ∼18 h. The resulting structure is vividly asymmetric and shaped like a rose thorn—elongated in the distal direction, curved in two dimensions with an oval base and a round tip. High-resolution analysis shows that the cytoskeleton forms from microvilli-like pimples that project actin filaments into the cytoplasm. These filaments become cross-linked into bundles by the sequential use of three cross-bridges: villin, forked and fascin. Genetic loss of each cross-bridge affects cell shape. Filament bundles associate together, with no lateral membrane attachments, into a cone of overlapping bundles that matures into an oval base by the asymmetric addition of bundles on the distal side. In contrast, the long bristle cell extension is supported by equally long (up to 400 μm) filament bundles assembled together by end-to-end grafting of shorter modules. Thus, bristle and hair cells use microvilli and cross-bridges to generate the common raw material of actin filament bundles but employ different strategies to assemble these into vastly different shapes.
Duverger's Hypothesis, the Run-Off Rule, and Electoral Competition
Authors: Callander Steven
Published: May 2005

I analyze a model of electoral competition with entry under the run-off rule. I consider both two- and multiple-party systems. The principal result is that two-party systems may prove stable under the run-off rule: I show that a continuum of equilibria exists in which only two parties enter and subsequent entry is deterred. This finding conflicts with the accepted wisdom on the run-off rule encapsulated by Duverger's Hypothesis. The results of the model are then reconciled with Duverger's Hypothesis and a more precise formulation is proposed.
Analysis of power law and log law velocity profiles in the overlap region of a turbulent wall jet
Authors: Afzal Noor
Published: May 2005

The two-dimensional turbulent wall jet on a flat surface without free stream is analysed at a large Reynolds number, using the method of matched asymptotic expansions. The open mean equations of the turbulent boundary layer are analysed in the wall and wake layers by the method of matched asymptotic expansions and the results are matched by the Izakson–Millikan–Kolmogorov hypothesis. In the overlap region, the outer wake layer is governed by the velocity defect law (based onUm, the maximum velocity) and the inner layer by the law of the wall. It is shown that the overlap region possesses a non-unique solution, where the power law region simultaneously exists along with the log law region. Analysis of the power law and log law solutions in the overlap region leads to self-consistent relations, where the power law index,α, is of the order of the non-dimensional friction velocity and the power law multiplication constant,C, is of the order of the inverse of the non-dimensional friction velocity. The lowest order wake layer equation has been closed with generalized gradient transport model and a closed form solution is obtained. A comparison of the theory with experimental data is presented.
Structure of the Bloch wall in multilayers
Authors: García-Cervera Carlos J
Published: May 2005

We present an analysis of the structure of Bloch walls in layered magnetic materials in the context of micromagnetics. We have obtained the
Γ
-limit of a one-dimensional reduction of the Landau–Lifshitz energy for a double layer in several asymptotic regimes. As a result, the optimal energy, the core length and the optimal shape of the Bloch wall have been determined. The effects of the interlayer spacing and the film thickness are studied. A comparison between the structure of the Bloch and Néel walls in multilayers is carried out. We illustrate all our findings by numerically minimizing the one-dimensional energy.