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Biomedical subjects

R Noack

Publications and source records attributed to R Noack.

At least 55 records · Page 3Linked to original sources
PubMed1985

[Comparative studies on the enzymatic absorption of protein hydrolysates in the small intestines of the rat. 3. The absorption of trypsin, thermitatic and trypsin thermitatic wheat gluten hydrolysates in comparison with equimolar mixtures of free amino acids].

Tryptic, thermitatic, and tryptic-thermitatic wheat-gluten hydrolyzates as well as their equimolar amino-acid mixture were perfused through proximal and distal parts of the intestine (10 cm length) of non-narcotized rats. The total amino-acid concentration of the perfused solution was 50 mM. The tryptic hydrolyzate showed a significantly lower absorption of nitrogen and total amino acids than the amino-acid mixture. Both the supplied forms were very different as to their absorption pattern of the amino acids. The high variability of the percental absorption of the individual amino acids of the tryptic hydrolyzate results in a high coefficient of variation. The absorption of nitrogen and total amino acids from thermitatic and tryptic-thermitatic hydrolyzates is equal to that from the amino-acid mixture. In a peptidic form glutamic acid is more rapidly absorbed from the two hydrolyzates, and methionine from the tryptic-thermitatic hydrolyzate in both the intestinal parts. As to alanine and glycine this concerns only the distal intestinal part for both the hydrolyzates. There are no differences between the absorption patterns of the two hydrolyzates but in comparison with the amino-acid mixture and the tryptic hydrolyzate differences were evident. The coefficients of variation of both the hydrolyzates are significantly lower as compared to those of the tryptic hydrolyzate and the amino-acid mixture. All forms of supply are more rapidly absorbed in the distal than in the proximal part of the intestine.

Amino Acids↗
PubMed1985

[Comparative studies on the enzymatic absorption of protein hydrolysates in the small intestine of the rat. 3. The absorption trypsins thermatatic and trypsin-thermatatic hydrolysates of a fava bean protein isolate compared to an equimolar mixture of free amino acids].

Tryptic, thermitatic, and tryptic-thermitatic Faba bean protein hydrolyzates as well as their equimolar mixture of amino acids were perfused through proximal and distal parts of the intestine (10 cm length) of non-narcotized rats. The total amino-acid concentration of the perfused solution was 50 mM. The absorption of nitrogen and total amino acids from the tryptic and tryptic-thermitatic hydrolyzates was lower than that from the amino-acid mixture, the absorption from the thermitatic hydrolyzate was in accordance with that from the amino-acid mixture. The absorption pattern of the amino acids which preferably undergo a peptidic absorption is similar with the three hydrolyzates: in the proximal intestinal part this concerns glutamic acid and serine, in the distal intestinal part--methionine, alanine, glycin, and serine. The absorption pattern of the amino acids is different between the three hydrolyzates and the amino-acid mixture. Between the absorption pattern of the amino acids from the three hydrolyzates little differences were evident only in the proximal intestinal part. The coefficients of variation of the tryptic-thermitatic hydrolyzates are in accordance with those of the amino-acid mixture, whereas that of the thermitatic hydrolyzates is significantly lower. In the distal intestinal part all supplied forms are more rapidly absorbed than in the proximal part of the intestine.

Amino Acids↗
PubMed1985

[Comparative study of the absorption of enzymatic protein hydrolysates in the small intestine of the rat. 2. The absorption of tryptic, thermitatic and tryptic-thermitatic casein hydrolysates compared with the equimolar composition of free amino acids].

Tryptic, thermitatic, and tryptic-thermitatic casein hydrolyzates as well as their equimolar amino-acid mixture were perfused through proximal and distal parts of the intestine (10 cm length) of nonanaesthesized rats. The total amino-acid concentration of the perfused solution was 50 mM. The absorption of nitrogen and total amino acids respectively did not reveal significant absorption advantages in favour of the hydrolyzates. In contrast to this, some peptidic bound amino acids of these hydrolyzates show a significantly better absorption as compared to free amino acids. At this, dependences of the kind of hydrolyzate and the part of the intestine are evident. Glutamic acid, e.g. is generally more rapidly absorbed when peptidic bound; methionine is more rapidly absorbed only from the thermitatic and tryptic-thermitatic hydrolyzates, and alanine and glycin only in the distal part of the intestine. Independent of the amino acid or peptide substrate the total absorption of all the amino acids is higher in the distal part of the intestine. The comparison concerning the ranking order of the single amino-acid absorption rates shows in the two parts of the intestine distinct differences between the amino-acid mixtures and the enzymatic hydrolyzates. The lowest differences were found between the thermitatic and the tryptic-thermitatic hydrolyzate. Both of them have approximately the same degrees of hydrolysis (30 and 35%, respectively). The variability of the amino-acid absorption from the three casein hydrolyzates is lower in comparison with the amino-acid mixture. The tryptic-thermitatic hydrolyzates have the lowest coefficients of variability.

Amino Acids↗
PubMed1984

Diet-induced thermogenesis in man: thermic effects of single proteins, carbohydrates and fats depending on their energy amount.

The diet-induced thermogenesis of 12 healthy males of normal body weight was measured by means of indirect calorimetry over 6 h after test meals of 1, 2 or 4 MJ protein (white egg, gelatin, casein), carbohydrate (starch, hydrolyzed starch) or fat (sunflower oil, butter). The totals of the thermic responses proved to be dependent on the type of nutrient supplied as much as on its quantity. The effect of 1 MJ protein was at least three times as large as that of an isocaloric carbohydrate supply. The investigated dietary fats produced no evident thermic response. The doubling of the energy intake of either casein or hydrolyzed starch led to the approximate doubling of the thermic effect.

Adult↗
PubMed1984

[Absorption of enzymatic protein hydrolysates and equimolar amino acid mixtures in the perfused small intestine of the rat].

Casein, wheat gluten or field-bean protein isolate (vicia faba) was hydrolyzed enzymatically by trypsin or thermitase (proteinase from Thermoactinomyces vulgaris). The degree of splitting of the protein peptide bounds was, resp., 18% or 30% for casein, 8% or 30% for wheat gluten and 16% or 29% for the field-bean protein isolate. The peptide pattern of the protein hydrolysates was measured by gel chromatography. The absorption of the enzymatic protein hydrolysates was compared with the absorption of the equimolar mixtures of free amino acids by perfusion of the distal or proximal part of the small intestine of nonanaesthesized rats. The absorption was measured on the basis of the amino acid disappearance from the perfused part of the small intestine and expressed as absorption of the total amino acids, of each single amino acid and as coefficient of variation of amino acid absorption. There are no differences in the total amino acid absorption of the tryptic casein hydrolysate and the three thermitatic protein hydrolysates compared with their corresponding mixtures of free amino acids. The absorption is decreased in case of larger oligopeptides. Their preceding mucosal hydrolysis is slower than the absorption of the splitting products. This is true for tryptic hydrolysates of wheat gluten and field-bean protein. The absorption patterns of the single amino acids are different for protein hydrolysates compared with their equimolar mixtures of amino acids in case of a same total absorption, too. The coefficient of variation is low (more equal amino acid absorption) in hydrolysates consisting of a homogeneous mixture of low molecular weight peptides. It is more increased in mixtures of free amino acids or in hydrolysates containing longer-chain peptides.

Animals↗
PubMed1983

[Field bean protein diet in hypercholesteremia].

The lipid-lowering effects of Vicia faba protein are well-known only from animal experiments. According to these studies Vicia faba protein is the most powerful cholesterol-lowering agents among vegetable proteins. Therefore we examined these effects in a group of patients with hypercholesterolemia (HLP type IIa). We observed a cholesterol-reducing efficacy of the Vicia faba protein comparable with those under soy protein diets.

Adult↗
PubMed1982

[Effect of long-time supply of medium-chain triglycerides on postprandial lipid metabolism and fatty acid pattern of membrane lipids in rats].

To characterize the effect of long-term supply medium-chain triglycerides on the lipid metabolism, the authors determined under postprandial conditions the ratio between the ketone body concentrations in the blood and the liver, the in vitro fatty-acid synthesis in the liver and the adipose tissue, the plasma and liver lipids and the fatty-acid and phospholipid spectra of the plasma and the erythrocytic, thrombocytic and liver mitochondrial membranes, in rats after 9 weeks on an isoenergetic diet containing 12% of medium-chain triglycerides or lard. The long-term supply of medium-chain triglycerides induced a 3-fold increase of the fatty-acid synthesis in the liver and the fatty tissue. In contrast to this, no differences in the concentrations of acetacetate and beta-hydroxybutyrate were detected in the liver and the adipose tissue. The triglyceride and cholesterol contents in the liver were significantly reduced. In spite of the increase of palmitic acid proportion as the end product of the de novo fatty-acid synthesis in the plasma lipids and the erythrocytic membrane, the proportion of essential fatty acids in the membrane lipids under study was not affected; the simultaneous supply of 3% of sunflower oil meets the requirements for essential fatty acids.

Adipose Tissue↗
PubMed1982

In vivo incorporation of C14-1-acetate into liver and plasma lipids of postnatally overfed rats.

Postnatal overnutrition due to breeding of rats in small nests (4 pups per dam) leads to distinct metabolic changes in later life stages even in conditions of ad libitum feeding. At an age of 5 months rats from small nests differ from those of large nests (14 pups per dam) in a significant higher level of liver triglycerides and cholesterol esters, whereas changes in plasma lipids concern only the increased cholesterol ester fraction. The relative distribution of in vivo incorporated C14-1-acetate into liver lipids shows a higher moiety in the triglyceride fraction of animals from small nests but no changes of the relative distribution of activity among lipid fractions of plasma. These changes of lipid metabolism are discussed in relation to the development of an obese state of postnatally overfed animals.

Acetates↗
PubMed1981

Action of sucrose polyesters on lipid metabolism in rats.

The action of sucrose polyesters (SPE) as undigestible fat-like compounds on lipid metabolism of growing rats was studied. Over a period of 4 weeks the animals were fed a semi-synthetic diet containing 6% of SPE with or without reduction of dietary fat. The substitution of dietary fats by SPE or the additional supply of SPE led to an increase of fecal lipid and cholesterol excretion, which was accompanied by a significant stimulation of in vitro cholesterol synthesis of the liver and by a significant reduction of liver cholesterol. The serum cholesterol level, however, was not affected, whereas the level of triglycerides both in serum and liver was significantly reduced to about 40% of that found in control animals.

Animals↗
PubMed1981

[Importance of hormone regulation systems to pork quality].

Separately and simultaneously occurring disorders in thyroid and adrenal functional circuits were recorded from 218 land race pigs, 01 line, in several experiments, in the GDR. No detrimental impact on post mortem pork quality was found to have been caused by disorders in each one of the two circuits separately, but measurable defects were established, following malfunction of both circuits. Also studied were consequences of disorders on the hormonal and cardiovascular systems as well as on fattening and slaughter performance.

Animals↗