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Biomedical subjects

V K Mazo

Publications and source records attributed to V K Mazo.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

[Characteristics of food anaphylactic reactions to proteins and protein preparations in guinea pigs with different duration of hexenal-induced sleep].

The state of guinea pig sensitization was studied in the direct test in vivo by induction of active food anaphylaxis (FA). The animals were orally sensitized with food allergens: chick ovalbumin (OVA), bovine serum albumin, and protein preparations N 1 and N 2 (PP N 1 and N 2). In guinea pigs with null hexenal-induced sleep (NHS) and long hexenal-induced sleep (LHS), 40 min, the duration of HS is reliably reproduced in repeated testing. The intensity of FA reactions in guinea pigs with NHS was less manifested than in the animals with LHS with both food allergens. Significantly higher allergenic properties of PP N 2 were expressed in the animals with LHS. It was shown that varying anaphylactic sensitivity of guinea pigs in the above groups was not related with different permeability of the gastrointestinal tract of these animals for OVA macromolecules. Possibilities of metabolic validation of increasing anaphylactic sensitivity of guinea pigs with LHS have been considered.

Anaphylaxis↗
PubMedDate not supplied

[Effect of an unbalanced food ration on induction and course of alloxan diabetes in rats].

Wistar rats were kept on a synthetic ration with different percentage of proteins (18, 9 and 50%) for 2 weeks. Then they were given subcutaneous injections of alloxan at a dose of 200 micrograms/kg of body mass. In some animals glycemia was established on the 7th day after the first administration of alloxan, in others--on the 3rd day after repeated administration of alloxan at a dose of 150 micrograms/kg of body mass. The animals were decapitated on the 14th and 30th day after establishing a hyperglycemic condition. Lethality percentage, a degree of glycemia, and at the end of the experiment insulinemia, body mass indices, indices for some organs were evaluated. A ration with an optimum and high content of protein was shown to decrease lethality percentage, reducing risks developing of a hyperglycemic condition, caused by alloxan. A ration with a high content of protein decreased a degree of severity of a diabetic condition, caused by alloxan.

Animals↗
PubMedDate not supplied

[The effect of cow's milk and its hydrolysates on the metabolism of 17-hydroxycorticosteroids and the functional state of the gastrointestinal tract in guinea pigs].

Two groups of noninbred male guinea pigs (initial bw 250-300 g) received test rations in which 50% of standard ration protein were substituted for milk protein (P 20/80) and its enzymatic hydrolysate (H 20/80). The influence of P 20/80 and H 20/80 on some parameters of the gastro-intestinal tract (GIT) barrier function and 17-OCS metabolism was studied. The action of H 20/80 as compared to P 20/80 was expressed in the intensified excretion of free fraction of 17-OCS and glucuronides. The content of hydroxylated glucocorticoids increased in both fractions. At the same time elevated total proteolytic activity in the gastric mucosa and a tendency to decreased GIT permeability for chicken ovalbumin macromolecules were observed in animals that received H 20/80. It has been suggested that enzymatic hydrolysates of food proteins influence endocrine regulation of metabolic processes.

17-Hydroxycorticosteroids↗
PubMedDate not supplied

[Characteristics of peptide preparations obtained during enzymatic hydrolysis and ultrafiltration of milk proteins for use in specialized nutrition products].

+Ultrafiltrated bovine milk proteins with whey protein/casein ratios 20/80, 60/40 and 97/3 were subjected to pancreatin hydrolysis, and the hydrolysates obtained were fractionated to high- and low-molecular weight (LMW) fractions by means of ultrafiltration. The preparations obtained were characterized according to routine physico-chemical indices, amino-nitrogen content, amino acids score, molecular weight distribution, and concentration of precipitating milk antigens. The capacity of LMW fractions for inducing oral anaphylactic sensitization in guinea pig and for changing its susceptibility to histamine LD50 was studied. The conclusion has been made that LMW preparations with whey/casein ratios 20/80 and 60/40 could be effectively used in specialized formulae intended for nutrition of allergic children and adults, nursing women, and also for enteral nutrition.

Adult↗
PubMedDate not supplied

[The effect of the increased absorption of food protein antigens from the intestines on the development of sensitization in guinea pigs].

Adult guinea pigs received intragastrically chicken egg ovalbumin (OA), its absorption into the blood was evaluated by radioimmunoassay, and 21 days later the degree of sensitization was estimated by active anaphylactic shock reaction and by the level of circulating specific antibodies. It was shown that the increased permeability of the gastrointestinal tract barrier to OA macromolecules led to a rise in the humoral immune response and anaphylaxis aggravation in the animals. Similar dependence was not observed when the heterologous antigen-bovine serum albumin was used to test the permeability. It has been suggested that the raised uptake of undigested food protein intensifies the possibility of alimentary hypersensitivity development.

Anaphylaxis↗
PubMedDate not supplied

[An experimental evaluation of the hypoallergenic action of fat constituents for specialized therapeutic products].

The influence of fatty compositions with varying proportions of polyunsaturated fatty acids (PUFA) omega-6 and omega-3 on the manifestation severity of anaphylaxis to ovalbumin (OVA), whole pasteurized cow milk (WPCM), and sensitivity to histamine LD50 were investigated in male guinea pigs. Hypoallergenic effect to OVA and WPCM, decreased sensitivity to to histamine LD50 were manifested in the animals which received the fatty composition with a high ratio of omega-6 and omega-3 PUFA (24, 20). A correlation was established between the hypoallergenic action of the fatty composition and the content of medium- and long-chain saturated fatty acids in this composition. The results obtained have been considered with respect to the characteristics of the immunomodulatory effects of PUFA omega-6, omega-3 and saturated fatty acids.

Anaphylaxis↗
PubMedDate not supplied

[An immunochemical analysis of enzymatic hydrolysates of milk and soy proteins intended for the production of specialized nutritional products].

The capacities of immunoelectrophoresis in identification and assay of antigenic protein in enzymatic hydrolysates of milk and soya have been evaluated. The hydrolysates obtained under the action of pancreatin and protosubtilin were studied in milk protein concentrates "Dialact" and casezit and soya protein isolate "Adrex". Two-dimensional immunoelectrophoresis according to Clarke and Freeman was used to analyze the antigenic component spectrum in the samples. It has been shown that beta-lactoglobulin, as compared to other milk proteins, is most resistant to pancreatin-induced proteolysis in vitro. Pancreatin-induced proteolysis has been shown to be useful for trypsin inhibitor inactivation in soya protein isolate. It was demonstrated that immunoelectrophoresis could be used for complex evaluation of protein hydrolysates intended for manufacturing specialized foodstuffs.

Antigens↗
PubMedDate not supplied

[A comparative experimental evaluation of the potential allergenicity of milk proteins and their hydrolysates obtained by different technological means].

Some samples of cow milk proteins and enzymatic hydrolysates prepared on their basis were investigated in experiments on male guinea pigs to elucidate their sensitizing properties and influence on sensitivity to histamine LD50. The data obtained are discussed with respect to a possible modulation of allergic reactions by the products of incomplete enzymatic proteolysis.

Allergens↗
PubMedDate not supplied

[Various features of the initial stages of assimilation of isotope-labelled dipeptide].

Tritium-labeled dipeptide Gly-Leu was administered to noninbred guinea pigs by intracardiac injections, and to Wistar rats--intra-intestinally, through a specially implanted catheter. It was found that after intravenous and intraintestinal administration of isotope-labeled dipeptide the "low-molecular label" was bound by serum proteins. Dissociation of the complexes "low-molecular label"--serum protein in 8 M solution of urea has evidenced a predominantly reversible character of interaction between the low-molecular ligand and protein macromolecule. The results obtained should be taken into consideration during assay of protein absorption from gastro-intestinal tract of laboratory animals.

Animals↗
PubMedDate not supplied

[Binding of 3H-alanine and 125I-diiodotyrosine with serum proteins in vitro and in vivo].

Considerable amount of complexes, formed after binding of 3H-alanine and 125I-diiodotyrosine with blood serum proteins in vivo and in vitro was found to dissociate as a result of gel filtration on microcolumns of Sephadex G-25 in presence of 8 M urea. The phenomenon observed may be considered among possible reasons responsible for overestimation of the adsorption rate of food proteins antigens in gastrointestinal tract of experimental animals.

Alanine↗
PubMedDate not supplied

[Complex experimental assessment of potential allergenicity of various isolates of soy proteins].

The complex evaluation was carried out of potential allergenicity of three soya protein specimens - IPS, IPS-1 and IPS-2 manufactured by Ardex R, USA, which were attended for employment as protein component of specialized infant formulae. The content of total protein, amino-nitrogen, peptide fractions of molecular weight below 9000 D, precipitating protein antigens, trypsin inhibitor, was studied in the specimens. The apparent digestibility was measured by a multienzymatic system in vitro. The allergenicity of isolates was compared by means of histamine LD50 resistance test in guinea pigs and also by the reaction of active anaphylactic shock (AAS). The evidences have been obtained that IPS specimen containing the lowest levels of trypsin inhibitor and small peptide levels is characterized by the lowest sensitizing activity in AAS and simultaneously decreases the animals' resistance to histamine in the highest degree. Apparent digestibility of all the three specimens did not differ significantly. A conclusion has been made that the evaluation is necessary of infant hypoallergenic formulae components by a complex of independent experimental data.

Animals↗
PubMedDate not supplied

[Food sensitization of guinea pigs with enzymatic hydrolysates of milk whey proteins].

Adult guinea pigs received intragastrically solutions of milk whey protein concentrate (CWPM), its enzymatic hydrolysate (HWPM) and peptide fraction (PF) obtained by means of HWPM ultrafiltration. Milk protein antigen content of CWPM, HWPM and PF was preliminary characterized with two-dimensional and rocket immunoelectrophoresis. Undigested beta-lactoglobulin (beta LG) absorbed from the gut, was measured three hours after the administration by means of competitive radioimmunoassay. Administration of proteins was repeated twice with daily intervals. Twenty one days later the levels of circulating anti-beta LG antibodies were measured by Farr's method and then the reaction of active anaphylactic shock was triggered by intravenous infusion of whole skimmed milk. It was established that while antigens including beta LG content decreased in the rank of CWPM-HWPM-PF the absorption of beta LG into the blood serum and the violence of acute anaphylaxis decreased also. The largest level of specific antibodies to beta LG was detected in animals that received the hydrolized protein the fact being connected with the presence of aggregated beta LG in this preparation. The employment of ultrafiltration of enzymatic hydrolyzate leads to elimination of the majority of noninactivated antigens from the filtrate, consequence of this being the low level of animal sensitization by this preparation. It has been concluded that ultrafiltration technology has good advances in manufacturing hypoallergenic milk formulae.

Animals↗
PubMedDate not supplied

[Tolerogenic effect of ovalbumin digestion products forming in the gastrointestinal tract of rats].

The authors studied the tolerogenic effect of ovalbumin digestion products absorbed into the blood from the gastrointestinal tract of rats and injected intravenously into mice 24 hours before immunization of these animals with native protein. The preparation is a fraction with a molecular mass of no less than 6,000 daltons obtained by gel filtration of blood serum of ovalbumin fed rats on a column with Sephadex G-25. The titer of antibodies to ovalbumin determined by the passive hemagglutination test reduced on the 14th and 20th days after parenteral immunization with native ovalbumin.

Animals↗
PubMedDate not supplied

[Absorption and the immune response to ovalbumin administered by various methods in the dogs].

Absorption and immune response to ovalbumin (OA) were studied in chronic experiments on dogs after intraenteral administration (5 dogs) and feeding (3 dogs) with non-boiled hen eggs. A modified concurrent radioimmunoassay was used to estimate the blood serum content of OA antigenic structures and antibodies to them. In 7 out of 8 dogs the antigen was detected in blood already after the first intraenteral administration or feeding. It was established that absorption of OA antigenic structures was more intensive after intraenteral administration than after feeding with hen eggs. Antibodies to OA were detected in blood on day 15 in case of intraenteral administration and on day 20 when the animals were fed with eggs. The blood antibody titre to OA in dogs receiving ovalbumin by intraenteral route was 10-fold higher as compared to that in dogs fed with hen eggs. The data obtained evidence a high potential risk of the body sensitization to food protein during intraenteral food administration, as it happens, for example, in tube intraenteral feeding.

Administration, Oral↗