摘要:

The digestive utilization of dietary proteins at different sites along the digestive tract and the effects of their ingestion on the function of the digestive tract (secretion of endogenous proteins, development of microflora) can be inferred from the proportions of dietary, endogenous or microbial proteins. A first approach was to examine the proportions of some characteristic amino acids. A more accurate interpretation could be made by studying the additional undigested protein provided by the ingestion of an ‘experimental’ diet whose composition was calculated, for example, with regard to the undigested protein obtained with a very digestible diet (milk in the calf). These interpretations were often insufficient and did not extract all of the possible information. Thus, more global methods with statistical criterions had to be used. Some allowed two proteins (correlation and linear regression, average relative difference, χ2) to be compared. Others made it possible to take many proteins into consideration (factorial correspondence analysis). Finally, examples were given to seek the respective proportions of many proteins in a complex mixture or to estimate the most probable amino acid composition of the ‘microbial + endogenous’ proteins which escaped digestion in the small intestine. These various approaches have been discussed, with examples taken from our experimental results obtained in the preruminant calf, to show their advantages and limitations. In any case, the quality of the interpretation depends on the quality of the available results on the amino acid composition of endogenous, microbial and undigested dietary

ISSN:0250-6807    

DOI:10.1159/000176720

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Maltitol is found to be enzymatically hydrolyzed by the small intestinal mucosa of man, rat, and rabbit and metabolized by everted sacs of rabbit intestine at a moderate rate. On in vivo perfusion of maltitol (15.3 µmol/min) through the small intestine, 19% of the sugar alcohol is digested by gnotobiotic rats. 120 min after stomach intubation of gnotobiotic rats, only 31% of the ingested maltitol is found in the ileum. A daily application of 35 g maltitol to 4 human beings does not influence the parameters of well-being, compatibility and fecal state. It is concluded that maltitol will be digested and utilized by man, rat, and rabbit

ISSN:0250-6807    

DOI:10.1159/000176721

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

There is a significant difference in plasma levels of the free fatty acids (FFA) in habitual coffee drinkers compared with a control group of non-coffee and decaffeinated-coffee drinkers. A significant difference in FFA levels between males and females was found under the same conditions of coffee consumption, in non-coffee drinkers and in decaffeinated-coffee drinkers.

ISSN:0250-6807    

DOI:10.1159/000176722

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

After infusion of sodium D(-)L(+)-lactate in healthy man the clearance of the D(-)-isomer from blood was 70% of that of the L(+)-isomer. Utilisation of L(+)-lactate may have been inhibited by the presence of the D(-)-isomer. The changes in blood pyruvate concentration and ketone body ratio were compatible with mitochondrial oxidation of D(-)-lactate to pyruvate. After infusion of a D(-)L(+)-lactate racemic mixture, the renal excretion of the D(-)-isomer was much greater than that of the L(+)-isomer, although peak blood concentrations of the L(+) were higher than those of the D(-)-isomer. After infusion of sodium L(+)-lactate, the renal excretion of D(-)-lactate increased 7 times, although no D(-)-lactate could be detected in the blood or in the sodium L(+)-lactate infused.

ISSN:0250-6807    

DOI:10.1159/000176723

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The concentration of manganese in the hair of normal newborn infants was found to increase significantly from 0.19 µg/g at birth to 0.965 µg/g at 6 weeks of age and 0.685 µg/g at 4 months when they were fed infant formula. There was an insignificant increase to 0.330 µg/g at age 4 months in breast-fed infants. After this age there was a slow decline in hair manganese to 0.268 µg/g in normal children at age 8 years and 0.434 in learning disabled (hyperactive) children. This is the third study reporting elevated hair manganese in learning disabled chil

ISSN:0250-6807    

DOI:10.1159/000176724

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The effects of a vitamin A-deficient diet and the subsequent supplementation with retinoic acid (10µg/g dry diet) on serum thyroid hormones in rats were studied. In vitamin A-deficient animals there are increased levels of thyroxine and triiodothyronine and changes in serum transport of these hormones. Retinoic acid was able to restitute both levels and serum transport of hormones as in control rats

ISSN:0250-6807    

DOI:10.1159/000176725

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Aim of this investigation was to correlate basal beta cell function and insulin sensitivity in healthy man. A group of 10 healthy subjects with normal body weight and glucose tolerance was studied. Insulin sensitivity was assessed by glucose disappearance rate after insulin injection (0.1 IU/kg body weight). Beta cell secretion rate was estimated by the evaluating of fasting C peptide circulating levels. A positive and significant relationship was observed between fasting C peptide concentrations and coefficients of insulin sensitivity (r = 0.694, p < 0.05). We conclude that in healthy man basal beta cell secretion rate plays an important role in determining the peripheral sensitivity to insulin. In particular, hormone sensitivity is directly proportional to pancreatic hormone production in basal condition.

ISSN:0250-6807    

DOI:10.1159/000176726

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

The role which two proteolytic enzymes (cathepsin D, CD and calcium-activated protease, CAP) might play in the early anabolic and subsequent catabolic phases of skeletal muscle protein metabolism was investigated in rats fed normal and protein-deficient (50 g/kg) diets. Enzyme measurements were performed on crude homogenate and subcellular fractions of mixed thigh muscle. In normal pregnancy there was no evidence that the changes in muscle protein mass which occurred were assisted by changes in the activities of CD or CAP. CAP activity was, however, reduced throughout protein-deficient pregnancy. Electron micrographs of gastrocnemius muscle samples taken on day 21 of pregnancy suggested increased lysosome numbers in the protein-deficient animals. However, the specific activity of CD in the muscle microsomal-mitochondrial fraction from these animals showed decreased specific activity. Thus, neither CD nor CAP play any major role in releasing amino acids from maternal skeletal muscle for placental and fetal use during protein deficiency. Changes in CAP activity in early pregnancy may indirectly help to protect the fetus from protein deficiency by allowing maternal protein mass to accumulate early in pregnancy for catabolism and use at a later stage.

ISSN:0250-6807    

DOI:10.1159/000176727

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Sweet lupines are presently being cultivated at the Experimental Station in Gorbea (Chile). Four cultivars, Lupinus albus cv Astra, L. albus cv Multolupa, Lupinus luteus cv Aurea and Lupinus angustifolius, were examined for the chemical composition of whole and dehulled seeds and testa. Whole seeds contain 34–35% protein. The varieties of L. albus contain 13 % oil. L. luteus and L. angustifolius contain about 5 % ether extract. Crude fiber ranged from 11 to 17 % in the whole seed. Unsaturated fatty acids, especially oleic and lin-oleic, make up about 80% of total fatty acids. The alkaloid content of the seed was 0.02%. The amino acid composition of the protein indicated that the main deficiency corresponds to the sulfur-containing amino acids, i.e. methionine + cystine. The protein efficiency ratio values for L. albus cv Multolupa was 1.08 and 2.50 for casein. Supplementation with DL-methionine at 0.1, 0.2, 0.3 and 0.4% of the diet significantly increased the basal value from 1.08 to 2.14, for the supplemented diet with 0.1% (p < 0.01). Higher levels of supplementation did not cause significant increases in the protein efficiency ratio. Apparent protein digestibility for the rat was 75 % for unsupplemented lupine. This value increased to about 79 % (p < 0.01) for the supplemented diets (casein 88.7%

ISSN:0250-6807    

DOI:10.1159/000176728

出版商:S. Karger AG    

年代:1983

数据来源: Karger

摘要:

Changes in concentrations of blood lead, cholesterol, tnacylglycerols, GOT and GPT enzymes, phosphorus, proteins, plasma calcium and magnesium, and erythrocyte magnesium were studied for 25 weeks in 4 groups of 6 rabbits each receiving different diets: I (controls), II (water with 9.66 µmol/l of lead), III (atherogenic) and IV (atherogenic + 9.66 µmol/l of lead). Differences observed, with respect to the diets, for lead, cholesterol, enzymes, proteins and erythrocyte magnesium were evident from the 42nd day on. Low lead doses raised the levels of cholesterol and tnacylglycerols in group II, whereas triacylglycerols were lower in the plasma of group IV in comparison with group III and were accumulated in the aorta. The elevation of enzymes in groups III and IV indicated heart and liver dysfunctions. There was a significant drop in erythrocyte magnesium in groups III and IV, which was especially marked in the latter group, with an interaction between the two diet

ISSN:0250-6807    

DOI:10.1159/000176729

出版商:S. Karger AG    

年代:1983

数据来源: Karger