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Biomedical subjects

V K Mazo

Publications and source records attributed to V K Mazo.

At least 91 records · Page 5Linked to original sources
PubMedDate not supplied

[Quantitative evaluation of the absorption of intact protein macromolecules and their large fragments from the gastro-intestinal tract into internal organs].

Basing on the literature data and their own findings, the authors assume that for the summary estimation of absorption of protein antigens, simultaneous assay of their content in the portal blood and lymph would be most correct. The method of dissociation with 8M urea of complexes, formed by blood serum proteins and tissues with low-molecular products of protein splitting, has been proposed for the quantitative estimation of exogenous high-molecular compounds that completely lost antigenic determinants of their initial protein.

Animals↗
PubMedDate not supplied

[Breakdown of the soluble soybean antigen in the digestive tract of adult rats].

Adult male Wistar rats received intragastrically a protein mixture containing 3H-labeled reserve protein of soy beans (PSB), the soy protein isolate 500-E of Ralston Purina Co (USA) being chosen as a protein source. Immunoreactive and TCA-precipitable 3H-PSB was determined in the stomach and small bowel content, 20 and 60 minutes after the administration. The experiment showed more complete inactivation of soy antigen as compared to chick ovalbumin (the authors' data), bovine serum albumin, chick ovomucoid and Kunitz trypsin inhibitor (the literature data). Basing on the results obtained, it is suggested that the soy reserve protein possesses low allergenic properties.

Animals↗
PubMedDate not supplied

[Organ distribution of bovine serum albumin administered intragastrically in the rat].

Radioimmunoassay was employed to examine distribution of antigenic structures of bovine serum albumin (BSA), absorbed by the gastrointestinal tract, in the blood serum and organs of intact rats. It was shown that 3 h after administering 3H-BSA an appreciable amount of its antigenic structures could be identified in the blood serum, liver, spleen, and carcass of the animals. The total amount of antigenic determinants of BSA which got into the internal environment of the body from the intestine amounted to about 0.2% of the dose administered. The highest specific content of antigenic structures of BSA supplied via the intestinal barrier was detected in the spleen.

Animals↗
PubMedDate not supplied

[Assessment of the in vitro digestibility of dietary proteins and of the degree of the breakdown of their antigenic structures by using polyenzyme systems].

A comparative assessment was made of the digestion of bovine serum albumin (BSA), chicken ovalbumin (OVA), and casein by means of the gastric juice--duodenal contents floccular gel structures (FGS) system and a four-enzymic system including trypsin, chymotrypsin, peptidase, and bacterial protease preparations. Decomposition of the BSA and OVA antigenic structures with the use of the two systems was also studied. Significant differences in BSA and OVA digestion by the gastric juice--FGS system were detected both with respect to amino nitrogen content and to the degree of their antigenic structure decomposition, whereas no such differences were observed when the four-enzymic system was used. The systems most accurately simulating the 'proteolytic conveyer' conditions of the gastrointestinal tract are preferable for the studies. The developed method is recommended for use in comparative assessment of the nutrient protein sensitizing properties.

Animals↗
PubMedDate not supplied

[Isolation of renin from human kidneys].

Isolation and partial purification of renin from human kidney was carried out as follows: defatting of the homogenized kidney; extraction with methyl cellosolve; chromatography on DEAE cellulose; affinity chromatography using immobilized pepstain. Activity of the preparation obtained was 0.1 GU/mg of protein. The preparation of human renin might be used for measurement of renin activity in blood of patients.

Angiotensinogen↗
PubMedDate not supplied

[Permeability of gastrointestinal barrier in rats for bovine serum albumin].

A study was made of the permeability of the gastrointestinal barrier of intact adult rats for bovine serum albumin (BSA) labeled with 3H during antigen administration into an isolated loop of the proximal jejunum and intragastric administration via a probe. The content of the tritium label was determined in the peripheral blood serum and liver cytoplasm obtained upon homogenate centrifugation. The content of the BSA antigenic determinants in biological fluids was determined by immunosorption. In addition, the presence of high-molecular peptides precipitated with trichloroacetic acid was also assayed in the fluids. It was demonstrated that an immunologically significant amount of BSA penetrated the internal medium of the body whatever the route of administration. In all the cases the content of BSA in the liver cytoplasm was significantly higher than in the blood serum. A considerable part of radioactivity falls within the high-molecular peptides. It is inferred that the liver plays the principal role in the deposition and catabolism of foreign antigenic structures.

Animals↗
PubMedDate not supplied

[Comparison of the resistance during proteolysis of the antigenic structure of bovine serum albumin, chicken ovalbumin and their carbohydrate-modified forms].

A study was made of the effect of Maillard reaction between epsilon-amino groups of proteins and sugar carbonyl groups on the resistance of protein antigens (AG) to proteolysis in model systems and in the course of digestion and absorption in the gastrointestinal tract of adult rats. It was found that in vitro pepsin and trypsin inactivate antigenic determinants of bovine serum albumin (BSA) modified by carbohydrate less readily than those of basic protein. At the same time in the course of studying the cleavage and absorption of 3H-proteins and their glucose derivatives in the rat body, lack of a significant stabilization of modified BSA and ovalbumin as compared with non-modified ones was discovered. The discrepancy of the data derived in vitro and in vivo is likely to be related to the inadequacy of the available enzymatic models with regard to real conditions of digestion in the gastrointestinal tract.

Animals↗
PubMedDate not supplied

[Breakdown of dietary proteins in the gastrointestinal tract of the adult rat].

Adult rats were examined for the time course of inactivation of antigenic determinants of tritium-labeled bovine serum albumin (BSA) or chicken ovalbumin administered intragastrically. Immunoreactive protein in the perfusates was determined according to the amount of the radioactive label retained by the immunosorbent. Antigenic determinants of protein disintegrated very rapidly after protein penetrated the gastrointestinal tract. Within 20 minutes after administration their amount did not exceed 12% of the dose administered. BSA disintegrated more rapidly than ovalbumin. At the same time after 20, 60 and 180 min an insignificant amount (about 1%) of immunoreactive protein penetrated the distal part of the small and large intestines. The amount of high-molecular fragments in all the parts of the gastrointestinal tract exceeded the discovered amount of immunoreactive protein. The data obtained indicate that a small amount of foreign food antigens is capable of overcoming the barrier of the cavitary proteolysis and of reaching those parts of the intestine where they can be absorbed in the intact form.

Animals↗
PubMedDate not supplied

[Effect of trypsin inhibitor on the proteolysis of chicken ovalbumin in the rat gastrointestinal system].

The authors studied the effect of soybean trypsin inhibitor (SBTI) on the preservation of antigenic determinants of chicken ovalbumin (OVA) in different parts of the gastrointestinal tract of adult rats given both proteins at a time. Predetermined the activity of trypsin in the small intestinal contents of rats given protein mixtures containing SBTI for 20 and 40 minutes. Marked inhibition of trypsin activity was observed during both time intervals. Protein structures of OVA that maintained the initial antigenicity were assayed by the immunofluorescent technique. It was found that following 20 minutes the integrity of antigenic determinants of OVA during feeding with SBTI mixtures was significantly higher in both parts of the small intestine, Meanwhile after one hour there were significant differences in the indicators in the distal portion and in the small intestine on the whole. The authors discuss the possibility of the effect of SBTI introduced with a protein mixture on the penetration of "intact" or partially decomposed protein with preserved antigenic properties into the internal medium of the body.

Animals↗
PubMedDate not supplied

[Trypsin and chymotrypsin distribution between the fractions of the duodenal contents and the parietal mucosal deposits].

An attempt has been made to assay the distribution of the typical representatives of pancreatic enzymes such as trypsin and chymotrypsin between dense and liquid fractions of the duodenal contents on an empty stomach and parietal mucous overlaps. The mass of the dense fraction being formed and specific activity of the enzymes under study are affected depending on the duodenal contents pH (4.5, 4.0, 3.5). Within the pH ranges indicated, specific activity of trypsin expressed in per cent of the total enzyme activity in the duodenal contents changed from 2-41 to 79-97%. It has been also shown that sorption of the enzymes is possible as well on the structures of the parietal mucous overlaps. A definite correlation has been demonstrated to exist between the activity of the enzymes under study in mucous overlaps and duodenal contents. Thus, the content of two endopeptidases of the pancreatic origin has been measured in the dense fraction of the duodenal contents on an empty stomach and mucous overlaps which are regarded as potential zones of heterophasic digestion in the intestinal cavity.

Animals↗
PubMedDate not supplied

[Preservation of the enzyme activity of horseradish peroxidase administered into the gastrointestinal tract of adult dogs and rats].

Enzymatic activity of horse radish peroxidase administered to the gastrointestinal tract of adult dogs and rats was assessed. It was discovered that in adult dogs, 30% of the protein reached the distal parts of the small intestine in a non-splitted form. As early as two hours after administering horse radish peroxidase over 15% of active enzyme was detectable in the gastrointestinal tract of adult rats. 0.5% of non-splitted enzyme was found in the rat large intestine.

Animals↗
PubMedDate not supplied

[Absorption of protein antigens in the gastrointestinal system of rats and guinea pigs].

The permeability of the gastrointestinal tract of adult rats for 3H-labeled bovine serum albumin (BSA) and 3H-chick albumin (CA) were studied and compared during intragastric administration via a tube. The content of structures with antigenicity of initial proteins was measured in the peripheral blood serum and salt liver extract obtained on homogenate centrifugation. It was found that CA, as compared with BSA, was capable to penetrate the gastrointestinal barrier in a greater amount and to preserve its initial antigenicity, which correlated with a higher resistance to acid denaturation and proteolysis. The permeability of gastrointestinal tract for CA was also examined in rats and guinea-pigs. It was demonstrated that the content of structures having antigenicity of initial CA in the blood serum and liver of rats was significantly higher than in guinea-pigs. It is concluded that this fact is related to the differences in the organization and functioning of the gastrointestinal tract in different animals.

Absorption↗
PubMedDate not supplied

[Effect of Maillard protein modification on protein resistance to hydrolysis by digestive proteinases].

A study was made of the influence of the Maillard reaction in proteins on their digestibility by pepsin, trypsin, and chymotrypsin. The model substrates were obtained by heating bovine serum albumin (BSA) and beta-lactoglobulin (BLG) with glucose for the preset period of time at 50 degree C. The rate of proteolysis by alkaline proteolytic enzymes was measured by the autotitration technique, whereas pepsin activity was determined by fluorometry. An evidence was obtained that digestibility by trypsin and chymotrypsin of BLG-glycose decreased, while the amount of protein bound carbohydrate increased. In the case of BSA, the incubation with glucose led at first to an insignificant lowering of digestibility by these two enzymes whereupon the protein resistance decreased. Thermal processing of both BLG and BSA in the absence of glucose led to a distinct growth of digestibility as compared to the native forms of proteins. As to pepsin, the authors failed to find any decrease in the digestibility of the Maillard compounds. It was revealed that the Maillard reaction in proteins had different effects on digestibility of different protein substrates by different proteolytic enzymes.

Allergens↗
PubMedDate not supplied

[Isolation and purification of angiotensinogen from swine and sheep plasma].

Angiotensinogen (a substrate of renin) was isolated from pig and sheep blood plasma. Content of angiotensinogen was estimated in the preparations obtained by an indirect biological method, which was based on estimation of an increase in blood pressure in rats, caused by angiotensin, liberated from angiotensinogen during incubation with renin. The preparation, obtained by ammonium sulphate fractionation of pig blood plasma, contained 0.4% of angiotensinogen. Angiotensinogen was also isolated from sheep blood plasma using ammonium sulphate fractionation, DEAE-Sephadex chromatography and gel filtration through Sephadex G-100; this preparation contained 10-13% of angiotensinogen.

Angiotensinogen↗