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Biomedical subjects

E Ia Stan

Publications and source records attributed to E Ia Stan.

At least 19 recordsLinked to original sources
PubMed2003

[Effect of casein phosphopeptides on bioavailability of the alimentary minerals].

Caseinophosphopeptides (CPPs) are phosphorylated casein-derived peptides which possess the ability to bind and solubilise minerals, such as Ca2+. The high bioavailability of Ca2+ fram milk and dairy products has been attributed to the production of CPPs which are produced following digestion of casein by the action of gastrointestinal proteinases. CPPs, which appear to be resistant to extensive proteolytic degradation, accumulate in the distal small intestine where they are purported to play a role in enhancing the passive absorption of Ca2+ and other trace elements. A recent human feeding tral reported improved Ca2+ and Zn2+ absorption following CPPs incorporation into food. This review summarises the production, characterization and potential applications of CPPs.

Biological Availability↗
PubMed1991

[Effects of an inhibitor of gastric secretion from k-casein on micro-lymphocirculation in the mesentery of the small intestine and intestinal motility in rats].

The casein inhibitor of gastric secretion, when applied to the mesentery of anesthetized rat at doses 0.01-10.0 micrograms in 0.1 ml activated the lymph flow due to enhanced contraction of lymphatic microvascular wall and valves. Moreover, casein inhibitor administrated intraintestinally at doses 5 mg in 0.5 ml on rat keep its lymphotropic activity.

Animals↗
PubMed1987

[The role of the adenylate cyclase system in the inhibition of gastric secretion by products of limited hydrolysis of kappa-casein].

The influence of the peptide inhibiting gastric acid secretion and derived from kappa-casein on the levels of cAMP, cGMP and adenylate cyclase activity of rat gastric mucosa was studied. Intravenous peptide preparation administration failed to alter cyclic nucleotide levels. The revealed decrease of adenylate cyclase activity was due to the presence of calcium in the investigated peptide preparation. It was assumed that cyclase system of the rat gastric mucosa cells were not involved in the inhibition of gastric acid secretion by the peptide preparations under study.

Adenylyl Cyclases↗
PubMed1986

[Mechanism of inhibition of acid secretion into the stomach by peptides of kappa-casein].

The inhibitory effect of peptides formed in a reaction of limited proteolysis on stimulated gastric acid secretion was studied in rats as well as the changes of gastrin level in the blood serum and antral gastric mucosa. The acid secretion decreased after intraluminal administration of the peptide by 51% in the rat isolated stomach, and gastrin level decreased by 8.3% in the blood serum. The mechanism of action of peptide derived from K-casein was discussed.

Animals↗
PubMed1986

[Amino acid composition and biological action of a peptide bioregulator from bovine k-casein].

Peptide material has been first isolated from k-casein pepsin hydrolysate. Its subcutaneous injection to hungry animals induced high amplitude (250-350 mV) and high frequency (16-20 Hz) oscillations of electrical potentials usually observed in food satiety and cholecystokinin administration. The peptide reduced respiratory and to a lesser extent heart rate. Its effect is temporary eliminated by naloxone. According to an aminogram, the peptide is a fragment of para-k-casein. A neurotropic peptide effect is connected with satiety regulation and milk consumption in the postnatal period.

Amino Acids↗
PubMed1983

[Effect of kappa-casein glycomacropeptide on gastrointestinal motility in dogs].

Glycomacropeptide, which provoked a significant inhibition of food motility of the stomach fundus on intravenous injection to dogs in a dose of 10 mg, was isolated from the products of restricted pepsin proteolysis of cow kappa-casein with the aid of gel chromatography on Sephadex G-25 and G-10. Glycomacropeptide administered on an empty stomach produced cyclic-repetitive vomiting. Physiological action of glycomacropeptide (inhibition of gastric secretion and motility) may play an important role in the preservation of biologically active milk proteins and peptides in the gastrointestinal tract of the newborn.

Animals↗
PubMed1982

[In vivo formation from rat milk proteins of a peptide inhibitor of gastric secretion].

A peptide fraction was isolated from the gastric content of 10-day-old suckling rats by Sephadex G-25 and G-10 chromatography. Intravenous injection of peptide (15 mg) had a powerful inhibitory action on gastric secretion of dogs with Pavlov pouches. It is assumed that this fraction is formed from rat casein and inhibits gastric secretion in the newborn, reducing rat milk proteolysis.

Animals↗
PubMedDate not supplied

[Chemical composition of casein glycomacropeptide components].

Alteration in pH and addition of urea (final concentration 3 M) did not affect the electrophoretic and chromatographic separation of glycomacropeptide. At the same time, urea (5 M) distinctly increased an amount of beta-component in separation by free electrophoresis. Sedimentation constant SO2OW and molecular weight of glycomacropeptide were equal to 1.35 S and 13000, respectively. Both fractions of glycomacropeptide had similar amino acid composition and contained phosphorus (0.4%). The variations were observed in the carbohydrate components of the molecules. The heavy component contained 5-fold higher concentration of sialic acids (9.7-9.6%), 2-fold higher concentration of galactose (13%) and acetyl galactosamine (5.0-4.0%) as compared with the beta-component (3.1-0.9%, 7.5% and 2.5%, respectively). These alterations in carbohydrate component of glycomacropeptide were suggested to affect the polymeric conformation of the molecule.

Caseins↗
PubMedDate not supplied

[Inhibiting action of glycomacropeptide on stomach secretion induced by various humoral stimulants].

Tests staged on dogs demonstrated the action of GMP to differ depending upon the nature of the gastric secretion stimulant actually used. The inhibition of the gastric juice secretion occurring against the background of multiple introduction of histamine or gastrin tetrapeptide amide was quite spectacular: the secretion dropped down to zero and the action was more prolonged than following administration of pentagastrin with which the secretion was not inhibited to such a sharp degree and the effect of GMP was less protracted. The mechanism of the GMP action of the gastric secretion and the causes of described differences require further investigations.

Animals↗
PubMedDate not supplied

[Comparative evaluation of bovine serum albumin and ovalbumin proteolysis in the small intestine of rat pups on artificial feeding].

Relationship between the type of protein digestion in gastrointestinal tract and coefficient of protein efficiency (CPE) was studied after artificial feeding of 15-21 days-old rats using milk substitutes. Distinctly low level of CPE was observed after rapid transfer of blood serum albumin (BSA) along the gastrointestinal tract accompanied by the protein intensive proteolysis. On the other hand, a considerable retardation of ovalbumin in intestine and the low rate of its proteolysis resulted in high efficiency of the protein consumption. Thus, a long-term transfer of protein in gastrointestinal tract is of paramount importance for its effective consumption at the early neonatal period. Therefore ovalbumin may be a better component in the protein complex of the milk substitutes as compared with BSA. Caseins, which are coagulated in stomach simultaneously with formation of peptides, affecting actively the functions of gastrointestinal tract, appear to maintain the most suitable for neonates rate of digestion and absorption of proteins, responsible for highly effective consumption of a protein mixture including casein. The most intensive digestion and absorption of the milk protein substitutes occurred in the middle and distal sections of small intestine. Cavital digestion of proteins was shown to be incomplete in spite of its relatively high efficiency.

Animals↗
PubMedDate not supplied

[A peptide bioregulator from bovine kappa-casein].

A number of peptides were isolated from pepsin hydrolyzate of cow k-casein by means of gel filtration on Sephadex G-50 and Biogel P-2, Dowex WX2 ion exchange chromatography in the pH step-wise gradient and dialysis using Sephadex G-10. The peptide material, after intravenous administration at a dose of 20 micrograms/kg of body mass, developed on electroencephalograms of various brain structures of starved rabbits the high amplitude, high frequent oscillations of electric potential corresponding to the effect of food satiation or to the action of cholecystokinin. Analysis of amino acid composition showed that the peptide fraction appears to be a fragment of para-k-casein moiety localized near one of Tyr residues containing in the protein molecule. Physiological effect of the peptide fraction was apparently related to regulation of satiation sense.

Amino Acids↗
PubMedDate not supplied

[Isolation, amino acid composition and type of action of gastric secretion inhibitors derived from k-casein].

Yield of an inhibitor of gastric secretion and its activity were increased after additional step of the k-casein purification as well as a result of increase in the enzyme/substrate ratio at the step of enzymatic hydrolysis and of substitution of the filtrate dialysis by extraction with ether. Amino acid analysis of the gel chromatographic fractions of inhibitor demonstrated the presence of para-k-casein fragments in its molecule. As shown by kinetics of inhibitory action the preparation included two inhibitors of gastric secretion. The inhibitor I exhibited its effect immediately after administration and increased the latent period of the gastric acidification. The effect of the inhibitor II was manifested with in 1.5-2 hrs after administration. The preparation isolated may be a useful drug in treatment of gastroduodenal impairments caused by hyperacidic states.

Amino Acids↗