Modifications in plasma cholesterol and apolipoproteins of hypercholesterolaemic rats induced by ethanol-soluble factors of Vicia faba.

High-fat-high-cholesterol diets containing casein or a Vicia faba bean (faba bean) protein concentrate as the protein source were given to rats for 5 weeks. When the faba bean protein concentrate or its ethanol extract was present in the diet, a marked decrease was found in the level of circulating cholesterol associated with the lower-density lipoproteins (very-low-, intermediate- and low-density lipoproteins) compared with the level found on the diets containing casein or the faba bean protein concentrate deprived of ethanol-soluble factors. Alterations in apoprotein pattern were detected after the different dietary treatments. In particular, apoA-I appeared in an unusual form with electrophoretic mobility faster than normal in all lipoprotein fractions after feeding the diets that did not lower plasma cholesterol. When the diets contained the faba bean protein concentrate or its ethanol extract, the apoA-I disappeared from the lower-density lipoproteins but its normal form and the unusual one were apparent in the high-density lipoproteins. A moderate increase in faecal excretion of acidic steroids was found after feeding the diets containing the ethanol-soluble factors, irrespective of the protein source. The results are discussed in relation to the presence of saponin and polyunsaturated lecithin in the ethanol extract of the faba bean protein concentrate.

Effect of factors of favism on the protein and lipid components of rat erythrocyte membrane.

Erythrocytes prepared from riboflavin- and tocopherol-deficient (RT-) and from control rats were used to investigate the mechanism of oxidative hemolysis by the factors of favism. RT- erythrocytes have a defense system against the oxidative stress which is blocked either where regeneration of GSH occurs or the scavenging of the radicals from the membrane is prevented. The oxidative factors used were isouramil, divicine and diamide. When RT- erythrocytes were treated with isouramil, GSH decreased to undetectable levels and was not regenerated. Complete hemolysis occurred, but no oxidation of SH groups of membrane proteins or formation of spectrin polymers was detected. A similar effect was observed with diamide. However, SH groups of membrane proteins were completely oxidized and spectrin polymers were formed. Extensive lipid peroxidation was also detected together with a 30% fall in the arachidonic acid level. Control erythrocytes treated with either isouramil or diamide were not hemolyzed. When treated with isouramil, after a fall in the first few minutes, the GSH level was completely regenerated after 20 min. Incubation with diamide caused extensive oxidation of SH groups of membrane proteins and formation of spectrin polymers. No lipid peroxidation was detected after treatment with isouramil, but the same decrease of arachidonic acid occurred as in RT- erythrocytes. These results support the hypothesis that oxidative hemolysis by the factors of favism is caused by uncontrolled peroxidation of membrane lipids.

Evaluation of protein quality: comparison of single-point and multi-point assays.

The quality of different protein sources having a wide spectrum of potential biological values has been assessed with multi-point and singly-point assays on growing Sprague-Dawley rats weighing 60 g. Values obtained with multi-point assays, expressed goth as absolute and relative values, were well correlated irrespective of the response parameter, i.e. as absolute and relative values, were well correlated irrespective of the response parameter, i.e. body weight change, body water or body nitrogen (r = 0.980). Single-point assay values based on body nitrogen content were also well correlated with the multi-point assays, but some discrepancies were noted for what assays based on body weight change was concerned. The modification of body protein concentration, in particular of rats fed the protein-free diet, was the main cause of these discrepancies. The problem of reference protein, when protein quality was expressed as relative value, was also discussed.

Long-term protein deficiency in adult rats : Effects on different proteins of a sympathetic ganglion.

The superior cervical ganglia (SCG) of adult rats were examined for total protein, LDH and TOH activity, and S-100 and tubulin content after 30 days of a proteinfree diet. After the depletion period, significantly lower values in all these parameters, in comparison with those in animals of the same age fed the complete diet, were found. The difference between the resistance of SCG and that of CNS to protein deficiency is discussed.

[A study of N/H2O ratios in Sprague-Dawley rats under variable conditions and its use for routine NPU determinations (author's transl)]. / Osservazioni sul comportamento del rapporto N/H2O in ratti del ceppo Sprague-Dawley: applicazione nella determinazione della utilizzazione proteica netta (NPU)

Nitrogen to body-water ratios were determined in a colony of rats of the Sprague-Dawley strain in order to investigate variations under variable conditions of age and diet. The study was conducted in order to verify the accuracy of body Nitrogen calculation from body-water determinations for the given colony under different experimental conditions. Only male animals were studied. The effect of age was studied for the intevals of 21, 28, 31, 42, 51, 84, and 126 days. N/H2O ratios were shown to increase exponentially with age within the range taken in consideration. Separate regression equations are given for 21 to 31 and for 31 to 51 day old animals relating the N/H2O ratio with age. The relationship between quality and quantity of protein of diets and the N/H2O ratio was investigated in 21 to 31 day old animals only. The N/H2O ratio was significantly higher in the animals fed the protein-free diet and diets with NPU less than 40. For these groups the factor 4.12 was obtained. Animals fed diets with NPU's ranging between 50 and 80 gave a factor of 3.94. For diets with NPU ranging from 50 to 80, the variation of the dietary protein level between 10 and 18% did not appear to influence the N/H2O ratio. NPU values calculated from analitically determined body Nitrogen were compared with NPU value calculated from body Nitrogen estimated using the established N/H2O ratios. The two sets of values are in good agreement supporting the use of the short-cut method for routine NPU determinations, given the appropriate factors are applied. It is recommended that such factors be experimentally determined for each own colony of rats.

[Serum free aminoacid levels in a group of hyperuricemic subjects from the Aosta Valley (author's transl)]. / Il quadro degli aminoacidi liberi del siero in un gruppo di soggetti iperuricemici anziani della Valle d'Aosta

The behavior of serum free aminoacids has been analyzed in a group of 31 hyperuricemic subjects and in a control group of 26 normal subjects. In the hyperuricemic males it has been observed a remarkable decrease of glycine and arginine values, while in the hyperuricemic females it has been noted a decrease in serum glycine and serine. The results are discussed.

Effects of litter size on protein, choline acetyltransferase (cat), and dopamine-beta-hydroxylase (DBH) of a mouse sympathetic ganglion.

Litters of 5, 10 and 17 pups were formed at birth. At 7, 14, 21, 28 and 60 days after birth mice were weighed and the cervical superior ganglia were examined for total protein and for CAT and DBH activities. At each age, the parameters examined were fitted into regression lines on the reciprocal of the litter size (L.S.R.); a highly positive correlation was found at each age between body weight and L.S.R., with maximum differences at weaning (day 21) followed by partial recovery after ad libitum feeding until day 60. A positive correlation was also found for total ganglion protein at days 21 and 28, with recovery practically completed at day 60. For CAT activity a positive correlation with L.S.R. appeared at day 14, with increasing coefficient and significance in later periods, until day 60. The temporal pattern of DBH activity for the 5-pup litter showed a peak at day 21, followed by a 35% decrease at day 28, with a steady level until day 60. A similar trend was observed for the 10- and 17-pup litters, but the peak occurred at day 28. Significant differences were found as early as day 7 between the 5- and the 17-pup litters, the maximum differences in the 3 experimental conditions being found at weaning, with a high and significant correlation coefficient, which persisted at day 60. Thus, the biochemical development and maturation of both presynaptic cholinergic nerve terminals and postsynaptic adrenergic neurones was evidently affected by the itter size during the suckling period, with persistent effects.