Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “PROTEINS/effects”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1956

Experimental production of gross atherosclerosis in the rat.

Gross atherosclerosis was produced in the rat by feeding purified diets containing cholesterol, sodium cholate, and thiouracil for periods up to 363 days. In a few weeks a marked increase of the serum cholesterol and beta lipoproteins as well as of the liver lipides was observed. Lesions visible in the gross were found on the intimal surfaces of the vessels of all 46 animals examined. These were most prominent in the heart valves and aortic arch. The earliest lesions, which were seen at 31 days, required Sudan staining for gross demonstration. Older lesions were visible without staining. Microscopic coronary artery lesions were present and in one instance were accompanied by massive myocardial infarction. Vascular lesions were characterized by medial and intimal lipide infiltration and cellular intimal plaque formation. In a part of this study the protein level of the diet was altered at the expense of sucrose. The hypercholesteremic response among the rats varied according to the dietary protein level. The lowest response was observed among those animals receiving the highest level of dietary protein. A difference, however, in the severity and extent of the arterial lesions among these relatively small groups of rats could not be established under these experimental conditions. In all these experiments a close correlation existed between the serum cholesterol levels and beta lipoproteins of the S(f)20-100 range.

Animals↗
PubMed1958

Effect of dietary proteins and amino acids on the susceptibility of mice to bacterial infections.

Groups of young albino mice were fed continuously four different types of diets and were compared with regard to (1) rate of weight gain; (2) resistance to experimental bacterial infections. The protein content of the four diets was as follows: (a) pellets: a minimum of 21 per cent "crude" protein (according to the manufacturer); (b) diet 20 C: 20 per cent casein; (c) diet 8 C: 8 per cent casein; (d) diet 8 C + AA: 8 per cent casein supplemented with 12 per cent of a mixture of essential amino acids. All diets provided an adequate supply of minerals and vitamins. They were administered ad lib. Three strains of pathogens virulent for mice were used for the infection tests, namely: Staphylococcus aureus, Mycobacterium fortuitum, and Mycobacterium tuberculosis bovis. The bacteria were injected by the intravenous route. The experimental regimens were begun at different times before infection, and were continued until death of the animal, or until termination of the experiment. It was found that mice on the 8 C diet exhibited much greater susceptibility to infection than did mice on the 20 C diet; mice receiving pellets were intermediate between these two groups. The infection-enhancing effect of the 8 C diet could be entirely corrected by amino acid supplementation (diet 8 C + AA). Indeed, mice fed diet 8 C + AA proved the most resistant to infection. The fact that animals fed pellets (which contain a minimum of 21 per cent protein) consistently died faster following infection than did animals fed diets 20 C or 8 C + AA suggests that qualitative characteristics of the protein in the regimen are as important as the quantity of protein fed in determining susceptibility to infection. The differences in susceptibility exhibited by the mice on the four experimental diets were the same whatever the species of bacterial pathogen used for the infection test, the size of the infective dose, and the duration of the disease. There was no apparent relation between the effects of the diets on the weight curves of the animals, and on resistance to infection. Mice on diet 8 C (which were most susceptible) gained weight as rapidly as those on 20 C and more rapidly than those fed 8 C + AA (which were most resistant). All the tests reported in the present paper were carried out with young mice, which were placed on experimental diets within 1 to 2 weeks after weaning. Preliminary experiments suggest that the relation between dietary factors and susceptibility to infection was more difficult to bring out in older animals. There was evidence also that this relation was most apparent during the first weeks that the animals were fed the experimental diets, and became less striking after several weeks.

Amino Acids↗
PubMed1959

Plasma protein turnover and tissue exchange; influence of dietary protein and protein depletion.

The rate of plasma protein turnover is more rapid in dogs receiving adequate dietary protein than when a diet devoid of protein is fed. Both albumin and combined globulins are involved in this change. The difference in turnover is reflected in a total protein half-life of 4.8 days with protein feeding versus 7.8 days without protein in the diet and in the metabolism of 1.0 and 0.65 gm. per kilogram of body weight per day on the respective diets. Additions of dietary protein from 10 to 30 per cent caused no further increase in the rate of plasma protein turnover. With protein depletion due to plasmapheresis and a very low protein diet there is evidence of reduced protein metabolism as indicated by nitrogen retention as well as a reduction in total plasma protein breakdown and interchange of isotope between plasma and tissue proteins. Following introduction of labeled plasma protein into the circulation the net amount of isotope transferred to tissues has been computed from the difference between total plasma protein breakdown and combined C(14) excretion in urine and expired air. In animals receiving adequate dietary protein, tissue transfer amounts to 70 per cent of the total lost from the plasma proteins each day while the percentage rises to 85 in depleted dogs deprived of protein. In dogs with both plasma and tissue proteins labeled it can be estimated that, under conditions of protein feeding, an amount of C(14) approximately equal to that lost from the plasma must recycle to account for the observed decrease in Apparent plasma protein turnover rate, (t(1/2) of 15 versus 5 days). Without protein in the diet the isotope contribution of the tissues to the maintenance of plasma protein levels must be as great as or greater than that transferred in the opposite direction.

Animals↗