bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolic studies in rats of [75Se]selenomethionine and of 75Se incorporated in vivo into rabbit kidney
Authors: Thomson Christine D. , Stewart R. D. H , Robinson Marion F.
Published: May 2005

1. [75Se]selenomethionine was administered to four rabbits and after 4 d their kidneys were removed and homogenized. The long-term fate in rats of an oral dose of this kidney homogenate (RK-75Se) was compared with that of an oral dose of [75Se]selenomethionine mixed with unlabelled rabbit kidney homogenate.

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

3. Intestinal absorption of RK-75Se was 87%; that of [75Se]selenomethionine was 91%. Urinary excretion of absorbed RK-75Se was 13·3% and that of [75Se]selenomethionine was 7·6%, in the 1st week.

4. Whole-body retention of 75Se was greater for [75Se]selenomethione than for RK-75Se but after the 1st week decreased at a similar rate in both groups. Tissue distribution of retained 75Se was also similar in both groups.

5. The initial utilization of 75Se in rabbit kidney is different from that of [75Se]selenomethionine. However, after the 1st week 75Se from these sources appears to be metabolized similarly, suggesting that Se from both is ultimately incorporated into the same metabolic pool.
Seasonal and nutritional effects on serum proteins and urea concentration in the reindeer (Rangifer tarandus tarandus L.)
Authors: Hyvärinen H. , Helle T. , Väyrynen R. , Vayrynen P.
Published: May 2005

1. The effects of seasonal conditions and nutrition on serum proteins and serum urea concentrations were studied in female reindeer and reindeer calves in Finland. With the exception of one group in winter, the reindeer were roaming wild in the forests. This one group was kept in captivity, out of doors, on a comparatively high nutritional plane. One group lived wild during the winter in very poor nutritional conditions.

2. A very clear seasonal variation in the serum protein and urea concentration was found. The serum protein concentration was low in late winter and increased rapidly during the summer, being high in the autumn. The serum urea concentration was also low in the winter and high in the summer. In the autumn, however, the serum urea concentration was again low.

3. Changes in the serum protein concentration were normally associated with the serum globulins. Only in the very poor-nutrition group did the albumin content decrease significantly. As a result of the large changes in the concentration of serum globulins, there were also considerable changes in the albumin: globulin ratio.

4. The serum protein concentration was much lower in the reindeer calves than in the adult reindeer. The concentration of globulins in particular was much lower than in the adults.
The effect of retinol and retinoic acid on physiological and biochemical changes in retinol-deficient rats
Authors: Krause R. F. , Beamer K. C. , Mccormick A. M. , Canterbury R. J. , Tryfiates G. P.
Published: May 2005

1. The effects of retinol and retinoic acid supplementation of retinol-deficient rats were studied for a variety of metabolic processes shown to be affected by retinol deficiency.

2. Retinol-deficient rats were found to have decreased body-weight, liver and testes weights, a degeneration of testicular germinal cells, an increased incorporation of labelled choline into liver and testes phospholipids, an increased protein synthetic activity (in vitro) of liver ribosomes, an increased transfer-RNA methyltransferase activity in liver and a decreased activity in testes, an increased DNA content of testicular nuclei, and a decreased uptake of [3H]thymidine by testicular nuclear DNA.

3. In retinol-deficient rats supplemented for 8 weeks with retinol these changes were reversed, measurements returning to control levels.

4. In retinol-deficient rats supplemented for 8 weeks with retinoic acid all changes were reversed except those in the testes.

5. Testicular signs of retinol deficiency appeared to be delayed when retinoic acid was added to the retinol-deficient diet of weanling rats. This suggests a sparing action of retinoic acid on the rat's utilization of retinol.

6. Suggestions are offered as to why retinoic acid will support growth and development but not spermatogenesis in the rat.
The use of three dye-binding procedures for the assessment of heat damage to food proteins
Authors: Hurrell R. F. , Carpenter K. J.
Published: May 2005

1. A study has been made of pure proteins heated either alone or in contact with sugars, so as to cause a severe fall in their reactive lysine contents, and also of commercial protein concentrates.

2. For unheated materials, and for bovine plasma albumin and fat-extracted, dried chicken muscle severely heated in the absence of sugar, Acid Orange 12 binding values (mmol bound dye/kg crude protein (nitrogen × 6·25)) were close to the sum of total histidine, total arginine and reactive lysine contents (mmol/kg crude protein (N × 6·25)), which we have termed HARL values. The dye-binding values and the HARL values were reduced similarly by heat treatment.

3. For materials in which protein and glucose had reacted under mild conditions (37°), the dye-binding capacity with Acid Orange 12 was unchanged even though the HARL value of these materials was considerably reduced. When protein and glucose or sucrose were heated more severely, the dye-binding capacity was slightly lowered but not to the same extent as the reduction in the basic amino acids.

4. Animal feeding-stuffs, whether unheated, industrially processed or deliberately heated, appeared to react with Acid Orange 12 in the same way as the model systems (selected to represent three types of heat damage: ‘advanced’ and ‘early’ Maillard and protein–protein damage).

5. Remazol blue binding values and fluorodinitrobenzene (FDNB)-reactive lysine values were similarly reduced in materials that had been severely heated, either with or without added sugars; however, when protein and glucose had reacted under mild conditions the fall in Remazol blue binding was less than that in FDNB-reactive lysine.

6. For the model materials, binding with cresol red was, in general, higher for heated samples but the results showed no correlation with FDNB-reactive lysine values. For meat and groundnut meals, changes in values after heat treatment were smaller than those that have been reported for soya-bean meals.
Anthropometric measurements and amounts of body fat and serum cholesterol in samples of three Nigerian populations
Authors: Watson R. S. , Etta K. M.
Published: May 2005

1. Skinfold thicknesses, arm circumferences, heights, weights and serum cholesterol levels were determined in ninety-one university students, 207 soldiers and 102 out-patients, all male subjects. Some of these measurements were used to determine the amount of body fat, Quetelet's index and mid-arm muscle circumference

2. Quetelet's indices and body-fat values obtained were similar to previously reported values for lean or moderately built males

3. Serum cholesterol levels were generally low, with means ranging from 3·98 mmol/1 for 18- to 29-year-old students to 5·19 mmol/l for 40- to 69-year-old out-patients

4. The mean values for triceps skinfold thickness, the amount of body fat and serum cholesterol levels for healthy adults obtained in this study are probably normal for northern Nigerian populations

5. There was a significant correlation between the amount of body fat and values for triceps and subscapular skinfold thicknesses, Quetelet's index and body-weight for all adults. The correlation between muscle circumference and the amount of body fat was significant for all subjects except adult soldiers.
Concentrations of amino acids and urea in the plasma of the preruminant 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 liquid diets

2. When calves were given whole milk (approximately 0·05 kg/kg live weight) at 10·00 and 17·00 hours there were marked decreases in PAA and slight decreases in PU for about 3–4 h after the morning feed. Both PAA and PU thereafter increased slightly and then remained constant for the next 10 h. In subsequent comparative experiments samples were taken 3 h after the morning feed. The variation in plasma methionine, isoleucine, leucine, phenylalanine, tyrosine and total PAA was apparently greater between than within animals

3. In calves transferred from a diet of whole milk to one consisting of diluted whole milk supplemented with appropriate nutrients, including amino acids, but deficient in methionine, PU increased markedly and plasma methionine decreased

4. Two calves (50–60 kg live weight) given the latter diet supplemented to give an intake of more than 4·5 g L-methionine/d together with 0·3 g cystine/d showed marked increases in plasma methionine. This was considered to correspond with the point at which methionine requirements were met and that under these conditions the methionine requirement for these calves (mean value ± SE) was 4·5 ± 0·2 g/d. In the same two calves PU decreased markedly with increasing levels of methionine supplementation up to 3·9 g/d and the estimated methionine requirement (mean value ± SE) was 3·9 ± 0·4 g/d.
The effect of pelleting on the voluntary intake and digestibility of leaf and stem fractions of three grasses
Authors: Laredo M. A. , Minson D. J.
Published: May 2005

1. Leaf is eaten in greater quantities than stem of similar digestibility. To determine whether this difference is caused by physical or chemical factors, leaf and stem fractions from Digitaria decumbens, Chloris gayana and Setaria splendida were fed ad lib. to sheep in the chopped and pelleted forms. Pellets were made from leaf and stem which had been ground through a screen with 3 mm holes. All sheep received a protein and mineral supplement

2. Voluntary intake of chopped leaf was 34% higher than that of the chopped stem fraction (40·3 and 30·0 g/kg body-weight0·75 respectively, P < 0·01) although dry matter digestibility ratios were similar (0·478 and 0·450 respectively, P > 0·05). The higher intake of leaf was associated with a larger surface area (13400 and 5200 mm2/g for chopped leaf and stem respectively), lower bulk density (60 and 180 kg/m3 respectively) and lower neutral-detergent fibre (706 and 724 g/kg respectively), acid-detergent fibre (383 and 413 g/kg respectively) and lignin (42 and 59 g/kg respectively) contents. Chopped leaf was retained in the reticulo-rumen for a shorter time than the stem fraction (19·9 and 26·4 h respectively)

3. Grinding and pelleting increased the voluntary intake of the leaf fraction by 88% and the stem fraction by 60%. This increased voluntary intake caused by grinding and pelleting was not accompanied by any significant changes in the chemical composition of the diet. Grinding and pelleting reduced the time that the food was retained in the reticulo-rumen and this change appeared sufficient to account for the observed increases in voluntary intake

4. It was concluded that the higher intake of the leaf fraction of grasses is caused by differences in retention time of food in the reticulo-rumen. These differences in retention time are caused by differences in physical properties and not chemical composition.
The subcellular localization of administered N-acetylneuraminic acid in the brains of well-fed and protein restricted rats
Authors: Morgan Brian L. G. , Winick Myron
Published: May 2005

1. This study investigated the subcellular localization of injected N-acetylneuraminic acid (NeuNAc) in brain. Forty pregnant rats were distributed into four groups. Two groups were given a 200 g casein/kg diel and the other two groups a 100 g casein/kg diet throughout gestation. One group from each of the low- and high-protein groups were given their respective diets for the first 11 d of lactation. On day 12 of lactation, 2·5 μCi [14]NeuNAc/kg body-weight were injected intraperitoneally into their pups. After 1 h the pups were killed, their brains removed and subjected to subcellular fractionation. On day 16 of lactation the other two groups were similarly treated.

2. In all groups of animals 80% of the [14C]NeuNAc incorporated into the brains was found in the synaptosomalfraction and the remainder distributed among the other subcellular fractions in proportion to their total NeuNA ccontent.

3. These results suggest that NeuNAc exerts its effects on behaviour via the synaptic membrane.
A method to measure the water-holding properties of dietary fibre using suction pressure
Authors: Robertson J. A. , Eastwood M. A.
Published: May 2005

1. Water-holding capacity (WHC) of dietary fibre is usually considered as the amount of water held but the manner in which water is held by the fibre matrix may be more relevant in understanding the role of fibre in nutrition.

2. A method used to determine WHC under physiological conditions has been adapted to determine how strongly water is held by fibre. Solutions of compounds, such as polyethylene glycol, of known osmotic potential are used to generate a suction pressure across a dialysis membrane containing a fibre sample. The WHC at each suction pressure can then be determined.

3. The method can be applied to water-soluble and water-insoluble sources of fibre. Fibre sources studied included potato fibre concentrate, bran and gum arabic.

4. Results are comparable to other similar systems of WHC measurement for gels and suggest that vegetable fibre has water-holding properties more akin to a true gel than bran. Bran has very poor water-holding properties.

5. Differences in WHC between fibre sources are more apparent if WHC is considered as fibre concentration (g fibre/g water).

6. Differences in the water-holding properties could be important in determining fibre activity in the gut.
Riboflavin deficiency in man: effects on haemoglobin and reduced glutathione in erythrocytes of different ages
Authors: Powers Hilary J. , Thurnham D. I.
Published: May 2005

1. Erythrocytes (RBC) from control and marginally riboflavin-deficient subjects were fractionated into nine fractions using a discrete density gradient.

2. Glutathione reductase (NAD(P)H: glutathione oxidoreductase;EC1.6.4.2) activity and aspartate aminotransferase (EC2.6.1.1) activity (with and without the appropriate co-enzymes) reduced glutathione, methaemoglobin, sulphaemoglobin and oxyhaemoglobin and susceptibility to peroxide were measured in RBC in the different fractions.

3. Glutathione reductase and aspartate aminotransferase activities and concentrations of reduced glutathione and oxyhaemoglobin all declined with age, while melhaemoglobin, sulphaemoglobin and susceptibility to peroxide increased with age.

4. The only significant differences noted in the RBC from marginally-riboflavin-deficient subjects by comparison with controls, were lower glutathione reductase activities and higher concentrations of methaemoglobin.

5. The role of riboflavin in those sytems controlling RBC integrity is discussed.
Guar bread: acceptability and efficacy combined. Studies on blood glucose, serum insulin and satiety in normal subjects
Authors: Ellis P. R. , Apling E. C. , Leeds A. R. , Bolster N. R.
Published: May 2005

1. Bread alone and supplemented with guar gum at three levels (50, 100 and 150 g/kg) was given to eleven non-diabetic subjects, and blood glucose and serum insulin were determined preprandialy, and at 30 min and 60 min after commencement of the meal. The satiating effect, up to 120 min, of the guar bread and its acceptability to the same group of normal volunteers was also studied.

2. No significant differences in blood glucose were observed between control and guar breads at 30 min and 60 min, apart from 100 g guar/kg bread at 30 min (P < 0·05). A significant difference in serum insulin was indicated between: control and 50 (P < 0·02) and 150 (P < 0·02) guar/kg breads at 30 min; control and 50 (P < 0·05), 100 (P < 0·001) and 150 (P < 0·05) guar/ke breads at 60 min.

3. There were no significant differences in the satiety scores for control and guar breads. Significant increases in satiety attributed to 150 g guar/kg bread were found when compared to: 50 g guar/kg bread immediately after eating (P < 0·05), 100 g guar/kg bread at 60 min (P < 0·02) and 50 and 100 g guar/kg breads at 120min (both P < 0·05).

4. There was a positive correlation between hedonic score and relative replacement of guar (r 0·62, P < 0·001, n 44) and from the regression line it was found that 50 and 100 g guar/kg breads produced hedonic scores close to a neutral response of 5, whereas 150 g guar/kg bread at a predictive score of 6·3 appeared to be unacceptable to our subjects.

5. Guar bread at the 100 g/kg level (59 g guar/kg bread) reduced the serum insulin by 48% at 60 min and is found to be an acceptable food product at this level of incorporation. However, more information is required to demonstrate the possible satiating potential of guar bread.
The effect of type and level of protein, fibre and starch on nitrogen excretion patterns in rats
Authors: Beames R. M. , Eggum B. O.
Published: May 2005

1. Three series of nitrogen balance experiments were performed with growing rats to test the effect of type and level of protein, fibre and starch on N excretion patterns. The design involved eighteen treatments in a 3×3×2 factorial experiment with five rats per dietary treatment. The eighteen treatments resulted from a combination of three protein treatments, three fibre treatments and two starch treatments. Protein treatments consisted of onelevel (15 g N/kg DM) of casein fortified with methionine, a protein of high digestibility, and two levels (15 and 20 g N/kg DM) of autoclaved brown beans (Phaseolus vulgaris), a protein source of low digestibility. The fibre treatments were two levels of cellulose powder and one level of barley hulls. The two starch treatments were autoclaved potato starch and autoclaved and raw potato starch (1:1, w/w).

2. The inclusion of raw potato starch reduced true protein digestibility markedly when the protein source was casein, but the corresponding biological values were increased significantly with this treatment. This strongly indicated a movement of urea from the blood to the intestines. This assumption was also supported by significantly lower blood urea concentrations in animals given raw starch. The influence of raw starch on true protein digestibility was, however, significantly less when cellulose and barley hulls were included. This is probably due to reduced transit time from fibre inclusion. The nature of the gut contents also supported this hypothesis.

3. The inclusion of raw potato starch when brown beans were the source of protein had much less effect on true protein digestibility and biological value than when casein was the protein source. This was probably due to the low digestibility of DM and protein in this food leaving sufficient energy and protein for maximum microbial growth. The inclusion of fibre also had little effect on N excretion patterns with the brown-bean diets.

4. An increase in the level of brown bean inclusion reduced true protein digestibility only on the diets containing raw starch whereas the biological value was consistently reduced regardless of starch treatment. The lower biological values were associated with significantly higher blood urea concentrations. Increasing the level of brown bean inclusion also resulted in higher fresh weights of caecum, colon and contents.

5. The present work proves that, through dietary manipulation, it is possible to affect nitrogen excretion patterns in rats.
The effect of dietary fibre sources on aflatoxicosis in the weanling male rat
Authors: Frape D. L. , Wayman B. J. , Tuck Mary G.
Published: May 2005

1. Two experiments with male weanling rats were conducted in which they received individually and restrictedly either a basal semi-purified diet containing starch as the principal carbohydrate or the same diet to which mixed aflatoxins were added in quantities providing from 0·13 to 0·4 mg aflatoxin B1 /kg diet. Various natural ingredients, or semi-purified sources of dietary fibre were substituted for a portion of the starch in the basal diet containing aflaloxin. The diets were fed for 13–14 weeks after which the rats were given ad lib. a commercial rodent diet until they were killed at 109 weeks of age.

2. Two further experiments were conducted in which twenty-four rats in each experimentreceived the basal diet plus aflatoxin, or diets in which a portion of the starch was replaced by gum arabic or by wheat offal. After 13 or more weeksthe absorption, retention and excretion of 14C-labelled aflaloxin B1 was measured in each rat.

3. The addition of gum arabic or wheat bran to the diet decreased the effects of the toxin in the first two experiments, but as measured by several characteristics, only wheat
bran provided an effect which persisted during the period when neither it nor the toxin was given. The effects included an apparent reduction in tumour incidence. The change in the content of starch in the basal diet, occurring as a consequence of adding the test ingredients is also considered to be an associated cause of the effects observed

4. In comparison to starch, wheat offal increased the total 14C in the faeces and the proportion of the total found during the first 48 h after dosing. Rats receiving starch excreted more 14C in their urine and retained more 14C in their livers. The differences between gum arabic and starch were not significant as measured by 14C excretion and retention. Liver size as a proportion of carcass weight was less in rats receiving wheat offal or gum arabic, and rats receiving wheat offal had a lower incidence of fat-loaded hepatocytes.

5. The interaction of dietary toxins, or drugs, with the ingredient composition of diet may affect animal response even when the diets are adequate and similar in nutrient composition. This may be of significance both in drug-safety studies and in animal production.
Silage intake, rumination and pseudo-rumination activity in sheep studied by radiography and jaw movement recordings
Authors: Deswysen A. G. , Ehrlein H. J.
Published: May 2005

1. The eating and ruminating activity of four rams given long-chopped silagead lib. in two daily meals was studied by jaw movement recordings. The events of rumination and pseudo-rumination were observed by fluoroscopy and by cineradiography.

2. The rate of eating was highest at the beginning of the main meal and then declined gradually.

3. The silage intake level was low.

4. The swallowed silage did not accumulate at the cardiac region but was forced into the dorsal sac of the rumen by the contractions of the reticulum and cranial sac of the rumen. For regurgitation the solid particles had to return via the ventral and cranial sac of the rumen into the reticulum.

5. Liquid reticular contents with floating solid particles were aspirated into the oesophagus during the maximum of the regurgitation contraction of the reticulum.

6. The rumination activity during the day presented a high proportion of pseudo-rumination cycles whereas during the night the rumination became progressively normal.

7. Pseudo-rumination was caused by delayed return of the fibrous silage particles into the reticulum. Thus in pseudo-rumination the regurgitated material consisted predominantly of fluid containing only a small quantity of solid particles.

8. The results explain why long-chopped silage intake is associated with pseudo-rumination, a lower breakdown of particles and a waste of digestion time.
Effects of cobalt deficiency in pregnant and post-parturient ewes and their lambs
Authors: Duncan W. R. H. , Morrison E. Rona , Garton G. A.
Published: May 2005

1. Two groups of ewes were fed on a cobalt-deficient diet throughout pregnancy; one group (group A) was given the diet from the beginning of pregnancy, whilst the other (group B) received the diet for 16 weeks before mating. The ewes in group A continued to receive the diet for 12 weeks post-partum.

2. The vitamin B12 content of serum was estimated on three occasions before parturition and, for group A ewes, at 12 weeks post partum. Urinary concentration of methylmalonic acid was also determined at intervals before the lambs were born.

3. Serum values for vitamin B12 indicated that the ewes in both groups were depleted of the vitamin, though those in group B were more severely affected, as was evidenced by the high incidence of perinatal mortality among the lambs born to these ewes. Perinatal mortality appeared to be associated with abnormally-high values for urinary concentration of methylmalonic acid.

4. Analysis of liver lipids and adipose tissue triacylglycerols of some of the vitamin B12-deprived lambs which died before, or within 1 d of, birth showed that, compared with the corresponding tissues of control lambs, these lipids contained unusually high proportions of odd-numbered fatty acids (mostly 15:0, 17:0 and 19:0). This observation is discussed in relation to the likelihood that, in vitmain B12-deprived lambs, propionate becomes available as a primer unit for fatty acid synthesis when the metabolism of its carboxylation product, methylmalonic acid, is impaired due to partlal lack of a vitamin B12-containing enzyme system.
Glutathione peroxidase activity and erythrocyte stability in calves differing in selenium and vitamin E status
Authors: Siddons R. C. , Mills C. F.
Published: May 2005

1. Glutathione peroxidase activity (EC1.11.1.9) and erythrocyte stability were measured in Friesian bull calves which were given for 36 weeks semi-purified diets either adequate or low in selenium or vitamin E or both.

2. Dietary Se or vitamin E content had no effect on growth rate and haematological vaiues. None of the calves exhibited clinical deficiency symptoms and serum aspartate amino transferase (EC 2.6.1.1) and creatine phosphokinase (EC 2.7.3.2) activities remained normal. Heart and skeletal muscles of all calves appeared macroscopically and microscopically normal at autopsy.

3. Glutathione peroxidase activity in plasma, blood and other tissues, except the testis, was significantly lower in calves receiving low dietary Se but was independent of dietary vitamin E content.

4. Plasma vitamin E levels decreased rapidly and to very low levels in calves given low vitamin E diets irrespective of the Se content of the diet.

5. A low dietary vitamin E intake increased the susceptibility of erythrocytes to auto- and peroxidative haemolysis whereas a low Se intake in the presence of adequate vitamin E did not. However, erythrocytes from calves receiving low Se and low vitamin E were more susceptible to peroxidative haemolysis than erythrocytes from calves receiving low vitamin E and adequate Se. The effect of dietary vitamin E content on osmotic haemolysis induced by hypotonic saline was variable.

6. The results suggest that measurement of blood glutathione peroxidase activity and the susceptibility of erythrocytes to auto- or peroxidative haemolysis could be used for the differential diagnosis of subclinical Se and vitamin E deficiency in ruminants.
Protein synthesis in tissues of growing lambs
Authors: Davis S. R. , Barry T. N. , Hughson G. A.
Published: May 2005

1. The fractional rate of protein synthesis (FSR) in tissues of nine growing lambs (4–5 months of age) was estimated following continuous infusion of L-[4,5–3H]leucine for a period of 7 h. Minimum and upper estimates of FSR were obtained assuming that the specific radioactivity (SRA) of leucine in blood plasma and tissue homogenate respectively defined that of leucyl tRNA.

2. Mean upper estimates of tissue protein FSR (/d) were skin 0·35, longissimus dorsi muscle 0·05, biceps femoris muscle 0·04, liver 0·54, rumen 0·79, cardiac muscle 0·09. Minimum estimates of tissue protein FSR ranged from 0·03 (muscle) to 0·15 (liver).

3. Plasma leucine flux was closely related to body protein content and dietary leucine absorption (r0·94).

4. The rate of whole-body protein synthesis (WBS) derived from plasma leucine flux corrected for oxidation and localized recycling of leucine into protein was similar to that calculated from the sum of daily protein synthesis in individual tissues using the upper estimate of FSR, i.e. 610 g/dv. 581 g/d.

5. The estimate of WBS derived from plasma leucine flux directly (241 g/d) was similar to that calculated from the sum of minimum estimates of daily protein synthesis in individual tissues (214 g/d).

6. The ratio, intracellular leucine SRA:plasma leucine SRA tended to increase with increasing dietary leucine absorption in all tissues although these factors were only significantly correlated (P< 0·05) in cardiac muscle, skin and rumen. Such relationships suggest an increased exchange of plasma leucine with intracellular leucine with increased food intake.

7. It was estimated that the energy cost of protein synthesis accounted for approximately 42% of daily heat production.
The effect of dietary protein source and saponins on serum lipids and the excretion of bile acids and neutral sterols in rabbits
Authors: Pathirana Chitra , Gibney M. J. , Taylor T. G.
Published: May 2005

1. Four groups of six rabbits were given purified diets in which the dietary variables were protein source (isolated soya-bean protein or cow's-milk protein) with or without saponin supplementation (10 g/kg).

2. Rabbits given soya-based diets showed significantly lower serum concentrations of triglyceride and cholesterol (P< 0·01). The latter changes were confined to the cholesterol fractions of β-lipoproteins.

3. These changes in serum cholesterol were associated with a significantly increased excretion of acid and neutral sterols in animals given soya-bean protein.

4. There was no evidence to suggest that the effect of dietary protein source on serum lipids and the excretion of total and individual sterols was influenced by saponin supplementation.

5. These results do not support the hypothesis that the hypocholesterolaemia associated with plant proteins is due to the presence of saponins.
Changes in the composition of digesta during passage through the small intestines of steers
Authors: McAllan A. B.
Published: May 2005

1. Dry matter (DM), organic matter (OM), nitrogenous constituents, carbohydrate constituents and pH were estimated in digesta taken from eight different sites in the small intestines of slaughtered steers given different diets. Amounts of constituents passing different sites were compared using cellulose as a non-digestibte marker.

2. Amounts of the different constituents entering the small intestines varied with the type of diet given but the patterns of removal of each constituent were similar regardless of diet.

3. DM and OM were removed uniformly down the length of the small intestines. Net digestibilities of 0·62 and 0·63 for DM and OM respectively of the amounts measured in segment 1 digesta (first 3 m post-pylorus) were found at the terminal ileum. DM and OM contents of segment 1 digesta were 5 and 8% higher respectively than in abomasal digesta. Significantly smaller amounts of digesta were found in the proximal quarter of the small intestines than in more distal sections. There was a 10% addition of water to digesta in segment 1 compared with abomasal digesta. Of the water entering the small intestines a net 65% was absorbed therein, most absorption occurring in the first half.

4. Ammonia nitrogen was removed uniformly down the length of the small intestines to a net extent of 75% of that in segment 1 digesta. There was an apparent increase of approximately 18% in the total N (TN) content of segment 1 digesta compared with abomasal digesta. There was an approximate net removal of 80% of the TN measured in segment 1 digesta during passage down the small intestines. Over 95% of the digestible TN was removed in the section of tract between 3 and 15 m from the pylorus. Net removal of nucleic acid N (NA–N) up to the distal ileum was 78% of that in segment 1 digesta, most removal occurred in the proximal quarter of the small intestine. Little or no net loss of diaminopimelic acid–N (DAP–N) occurred in the small intestine.

5. Of the carbohydrates entering the small intestines, there was little or no removal of rhamnose, arabinose or xylose. Net removal of ribose, mannose, galactose and ‘starch’ glucose up to the distal ileum was 82, 76, 54 and 70% respectively of the amounts found in segment 1 digesta. All disappeared uniformly down the length of the small intestine.
The excretion of selenium in bile and urine of steers: the influence of form and amount of Se salt
Authors: Symonds H. W. , Mather Denise L. , Vagg M. J.
Published: May 2005

1. The excretion of 75Se and stable Se in bile and urine was measured in four steers during 6 h after intravenous injections of 75Se as either selenite or selenate containing either 5 or 5000 μg carrier Se.

2. When 5000 μg Se were given, the rate of urinary excretion and plasma clearance of 75Se was similar for both salts. Approximately 23% was excreted in urine and plasma clearance was triexponential, the mean half-life (t½) of the successive components, α, β and γ, being 2·3, 15·2 and 465 min respectively. The amount of 75Se excreted in bile was small; 1·94% of the 75SeO32− and 0·86% of the 75SeO42− dose.

3. When 5 μg Se were given the plasma clearance of 75Se was initially biexponential but the entry of 75Se-labelled protein from the liver caused an increase in plasma radioactivity after 30–40 min. The effect was most marked after 5 μg 75SeO32− when plasma 75Se radioactivity returned to 60% of the activity present at 2 min. Values for t½ of the two components of clearance for 75SeO32− and 75SeO42− were respectively α 2·6 and 2·5 min, and β 15·9 and 36·6 min. Similar amounts of 75Se appeared in bile (0·2% of the dose) after injections of either salt but much less 75Se was excreted in urine after 75SeO32− (6%) than after 75SeO42− (37%).

4. At low dosage rates (5 μg) Se is more readily incorporated into tissues from SeO32− than from SeO42−.
Availability of lysine in protein concentrates as determined by the slope-ratio assay with chicks and comparisons with rat, pig and chemical assays
Authors: Major E. J. , Batterham E. S.
Published: May 2005

1. A slope-ratio assay was developed to determine the availability of lysine in protein concentrates for chicks, Two protein concentrates were assessed per assay, using three levels of incorporation into the basal diet.

2. Availability of lysine, expressed as a proportion of total lysine in five protein concentrates was: cottonseed meal 0·83, fish meal 1·00, meat-and-bone meal 0·86, soya-bean meal 0·93, sunflower meal 1·01.

3. The five protein concentrates had previously been assayed for available lysine with slope-ratio assays for pies and rats (Batterham et al. 1979; Batterharn et al. 1981), There was little relationship between the results for chicks and those for pigs and rats. For pigs, availability estimates ranged from 0·43 for cottonseed meal to 0·89 for fish meal. For rats, availability estimates ranged from 0·49 for sunflower meal to 1·04 for fish meal.

4. The results for chicks were in closer agreement with values obtained using the Silcock available-lysine assay (Roach et al. 1967) and the direct 1-fluoro-2,4-dinitrobenzene procedure (Carpenter, 1960). By contrast, there was litlle relationship between the chemical tests and results for pigs or rats.
Protein metabolism in growing lambs fed on fresh ryegrass (Lolium perenne)–clover (Trifolium repens) pasture ad lib. 1. Protein and energy deposition in response to abomasal infusion of casein and methionine
Authors: Barry T. N.
Published: May 2005

1. Male lambs that had been born in autumn and wintered on forage diets were cannulated in the abomasum, confined indoors in individual pens, and fed on fresh primary growth ryegrass (Lolium perenne) – clover (Trifolium repens) pasture ad lib, for a 12-week period during spring. Mean diet organic matter digestibility (OMD) was 0/76, nitrogen content 29 g/kg dry matter (DM) and metabolizable energy (ME) content 11.1 MJ/kg DM. Thirteen lambs were infused into the abomasum with 44 g sodium caseinate +0/5 g L-methionine/d and 12 lambs were similarly infused with equivalent amounts of inorganic sodium and phosphorus. Initial live weight was 16/5 kg.

2. The twenty-five treatment lambs were slaughtered at the end of the experiment, and thirteen similar lambs were slaughtered when the experiment commenced. Body composition was determined and rates of protein, fat and energy deposition were calculated using comparative slaughter procedures.

3. Voluntary herbage DOM intakes tended to be slightly greater for control than protein-infused lambs, but calculated ME intakes including that infused as amino acids were similar for the two groups. Live-weight gains were 79 and 99 g/d for control and protein-infused lambs respectively (P < 0/05) and corresponding values for carcass gain: live-weight gain were 0/44 and 0/50 (P < 0/01), Wool growth was markedly increased by the amino acid infusion.

4. Carcass and whole body protein content was increased 10 g/kg by the protein infusion (P < 0/01) and fat content depressed approximately 25 g/kg (P < 0/05). Rates of protein deposition in both carcass and wool-free whole body were markedly increased by protein infusion, and total deposition including wool was 12.6 and 21.0 g/d for control and protein-infused lambs (P < 0/001). Energy deposited in protein as a proportion of total energy deposition was 0/27 and 0/41 for control and protein-infused lambs (P < 0/001), but total energy retention and the efficiency of utilization of ME for growth did not differ between the two groups of lambs.

5. It was estimated that 60 and 100 g total amino acids/d were absorbed from the small intestine in the control and protein-infused lambs respectively, corresponding to 0.16 and 0/25 of total ME intake. It was concluded that absorption of protein from the small intestine was limiting protein deposition in the growing lambs fed on fresh ryegrass-based spring pasture in this study. Absorption of cystine+methionine was specifically shown to be limiting. However, the protein deficiency was not a major factor in the low value for the efficiency of utilization of ME for growth for this diet (0/30).
Influences of dietary sucrose and urea on transfer of endogenous urea to the rumen of sheep and numbers of epithelial bacteria
Authors: Kennedy P. M. , Clarke R. T. J. , Milligan L. P.
Published: May 2005

1. The rates of transfer of plasma urea to the rumen of six sheep given brome grass (Bromus inermis) pellets alone or with supplements of sucrose or urea were determined using [14C]urea and14C-labelled sodium bicarbonate infusions during three periods.

2. The sheep were slaughtered after the third period and samples of rumen epithelium were taken for assessment of numbers of adherent bacteria.

3. Maximum transfer (0·31 g nitrogen/h) of urea to the rumen was observed for sheep given supplements of 150 g sucrose/d plus 20 g urea/d. Maximum clearance of plasma urea to the rumen (rate of urea transfer to the rumen per unit plasma urea concentration, 5·8 1/h) was observed for sheep given 300 g sucrose/d.

4. Urea clearance to the rumen was negatively related to rumen ammonia concentration; the slope of the relationship was increased with each addition of sucrose to the diet.

5. Numbers of facultative bacteria adherent to the rumen epithelium were increased by urea and sucrose supplements.

6. The results are discussed in relation to a hypothesis which relates the ureolytic capability of the bacteria adherent to the rumen epithelium to the control of the rate of transfer of urea into the rumen.
The absorption and secretion of calcium in the gastrointestinal tract of germ-free and conventional chicks
Authors: Palmer Maureen F. , Rolls B. A.
Published: May 2005

1. The uptake, transport and secretion of calcium into the gastrointestinal tract of germ-free (GF) and conventional (CV) chicks was determined by a variety of in vivo and in vitro techniques using45Ca as a marker following a standard fast-feed regimen.

2. Following an oral dose of Ca in conscious chicks, the transit time of digesta in the GF birds was appreciably faster than in the CV controls.

3. Although the proportion of the Ca dose absorbed was similar in both groups of chicks, the accumulation of Ca in the intestinal wall was much greater in CV birds. Distribution of the labelled Ca in plasma and bone was similar in both groups.

4. Following intravenous Ca injection in conscious chicks the Ca secretion into the intestinal lumen was similar in both groups, but the amount appearing in the gut wall was appreciably greater in CV chicks.

5. There were regional differences in the ability of the gut to absorb Ca. There was a tendency for Ca uptake to be greater in the GF chicks but only in the proximal ileum did this approach significance.

6. When the Ca was confined to an intestinal loop the uptake/g tissue was similar in the proximal ileum of both groups but significantly greater in the distal ileum of the GF group. Uptake/10 mm gut was similar in both groups at both the proximal and the distal site.

7. It is suggested that the absence of a microbial load does not affect the ability of the enterocyte to absorb Ca but the subsequent removal of the absorbed load from the intestinal wall is appreciably slower in the CV group.
The Complex Interplay between the Neck and Hinge Domains in Kinesin-1 Dimerization and Motor Activity
Authors: Bathe Friederike , Hahlen Katrin , Dombi Renate , Driller Lucia , Schliwa Manfred , Woehlke Guenther
Published: May 2005

Kinesin-1 dimerizes via the coiled-coil neck domain. In contrast to animal kinesins, neck dimerization of the fungal kinesin-1 NcKin requires additional residues from the hinge. Using chimeric constructs containing or lacking fungal-specific elements, the proximal part of the hinge was shown to stabilize the neck coiled-coil conformation in a complex manner. The conserved fungal kinesin hinge residue W384 caused neck coiled-coil formation in a chimeric NcKin construct, including parts of the human kinesin-1 stalk. The stabilizing effect was retained in a NcKinW384F mutant, suggesting important π -stacking interactions. Without the stalk, W384 was not sufficient to induce coiled-coil formation, indicating that W384 is part of a cluster of several residues required for neck coiled-coil folding. A W384-less chimera of NcKin and human kinesin possessed a non–coiled-coil neck conformation and showed inhibited activity that could be reactivated when artificial interstrand disulfide bonds were used to stabilize the neck coiled-coil conformation. On the basis of yeast two-hybrid data, we propose that the proximal hinge can bind kinesin's cargo-free tail domain and causes inactivation of kinesin by disrupting the neck coiled-coil conformation.
Understanding Interaction Models: Improving Empirical Analyses
Authors: Brambor Thomas , Clark William Roberts , Golder Matt
Published: May 2005

Multiplicative interaction models are common in the quantitative political science literature. This is so for good reason. Institutional arguments frequently imply that the relationship between political inputs and outcomes varies depending on the institutional context. Models of strategic interaction typically produce conditional hypotheses as well. Although conditional hypotheses are ubiquitous in political science and multiplicative interaction models have been found to capture their intuition quite well, a survey of the top three political science journals from 1998 to 2002 suggests that the execution of these models is often flawed and inferential errors are common. We believe that considerable progress in our understanding of the political world can occur if scholars follow the simple checklist of dos and don'ts for using multiplicative interaction models presented in this article. Only 10% of the articles in our survey followed the checklist.
Epidermolysis Bullosa Simplex Associated With Muscular Dystrophy and Cardiac Involvement
Authors: Celik Canan , Uysal Hilmi , Heper Aylin Okcu , Karaoglan Belgin
Published: May 2005

We report a new clinical variant of epidermolysis bullosa simplex with muscular dystrophy (EBS-MD) that was associated with cardiac involvement. A 33-year-old patient had atrial fibrillation, pericardial effusion, and hypokinetic left ventricular cardiac walls. The muscle biopsy material revealed diffuse endomysial fibrosis and small atrophic muscle fibers with rounded contours. A positive desmin expression with abnormal localization in the subsarcolemmal groups was observed. We concluded that patients with EBS-MD should be investigated carefully when there are associated cardiac findings.
Direct isolation and identification of promoters in the human genome
Authors: Kim Tae Hoon , Barrera Leah O. , Qu Chunxu , Van Calcar Sara , Trinklein Nathan D. , Cooper Sara J. , Luna Rosa M. , Glass Christopher K. , Rosenfeld Michael G. , Myers Richard M. , Ren Bing
Published: May 2005

Transcriptional regulatory elements play essential roles in gene expression during animal development and cellular response to environmental signals, but our knowledge of these regions in the human genome is limited despite the availability of the complete genome sequence. Promoters mark the start of every transcript and are an important class of regulatory elements. A large, complex protein structure known as the pre-initiation complex (PIC) is assembled on all active promoters, and the presence of these proteins distinguishes promoters from other sequences in the genome. Using components of the PIC as tags, we isolated promoters directly from human cells as protein-DNA complexes and identified the resulting DNA sequences using genomic tiling microarrays. Our experiments in four human cell lines uncovered 252 PIC-binding sites in 44 semirandomly selected human genomic regions comprising 1% (30 megabase pairs) of the human genome. Nearly 72% of the identified fragments overlap or immediately flank 5′ ends of known cDNA sequences, while the remainder is found in other genomic regions that likely harbor putative promoters of unannotated transcripts. Indeed, molecular analysis of the RNA isolated from one cell line uncovered transcripts initiated from over half of the putative promoter fragments, and transient transfection assays revealed promoter activity for a significant proportion of fragments when they were fused to a luciferase reporter gene. These results demonstrate the specificity of a genome-wide analysis method for mapping transcriptional regulatory elements and also indicate that a small, yet significant number of human genes remains to be discovered.
Identification of genomic features using microsyntenies of domains: Domain teams
Authors: Pasek Sophie , Bergeron Anne , Risler Jean-Loup , Louis Alexandra , Ollivier Emmanuelle , Raffinot Mathieu
Published: May 2005

The detection, across several genomes, of local conservation of gene content and proximity considerably helps the prediction of features of interest, such as gene fusions or physical and functional interactions. Here, we want to process realistic models of chromosomes, in which genes (or genomic segments of several genes) can be duplicated within a chromosome, or be absent from some other chromosome(s). Our approach adopts the technique of temporarily forgetting genes and working directly with protein “domains” such as those found in Pfam. This allows the detection of strings of domains that are conserved in their content, but not necessarily in their order, which we refer to as domain teams. The prominent feature of the method is that it relaxes the rigidity of the orthology criterion and avoids many of the pitfalls of gene-families identification methods, often hampered by multidomain proteins or low levels of sequence similarity. This approach, that allows both inter- and intrachromosomal comparisons, proves to be more sensitive than the classical methods based on pairwise sequence comparisons, particularly in the simultaneous treatment of many species. The automated and fast detection of domain teams, together with its increased sensitivity at identifying segments of identical (protein-coding) gene contents as well as gene fusions, should prove a useful complement to other existing methods.