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A Piñeiro

Publications and source records attributed to A Piñeiro.

67 records · Page 4Linked to original sources
PubMed1982

Interactions of different albumins and animal sera with insolubilized Cibacron Blue, Evaluation of apparent affinity constants.

1. A high concentration Cibacron Blue-Sepharose derivative has been used to study the affinity chromatography of albumin from eight animal species. 2. The apparent affinity constants for albumin varies between 3.9 x 10(4) M-1 and 0.9 x 10(4) M-1, in the order: Human greater than rabbit greater than horse greater than pig = dog greater than bovine greater than rat greater than chicken. 3. Other serum proteins were also bound to the gel, particularly lipoproteins and alpha 2-macroglobulin.

Animals↗
PubMed1978

Isolation and properties of bovine colostral trypsin inhibitor.

The trypsin inhibitor of bovine colostrum was isolated by affinity chromatography, and impurities removed by trichloroacetic acid precipitation. The inhibitor showed electrophoretic microheterogeneity which was not due to sialic acid content. It inhibited bovine and rat trypsin, showed weak inhibition of bovine chymotrypsin and was inactive against rat chymotrypsin and bovine renin, kallikrein, thrombin and trypsinogen. The dynamics of secretion of the inhibitor in the first 8 milkings post-partum were very similar to those of colostral immunoglobulins.

Animals↗
PubMed1978

The effect of trypsin and chymotrypsin on the antibacterial activity of complement, antibodies, and lactoferrin and transferrin in bovine colostrum.

The effect of trypsin and chymotrypsin on antibacterial factors in bovine colostrum has been studied. Endogenous complement in colostrum was extremely sensitive to both enzymes. IgM was attacked by chymotrypsin but not by trypsin. Trypsin slowly attacked IgG1, causing loss of biological activity due to cleavage of both light and heavy chains. IgG1 was only very slightly attacked by chymotrypsin. Lactoferrin and transferrin in the iron-free state were both susceptible to proteolysis, but the iron saturated forms were more resistant and tended to give rise to stable iron-binding fragments.

Animals↗
PubMed1977

The effect of trypsin and chymotrypsin on the bactericidal activity and specific antibody activity of bovine colostrum.

Digestion of bovine colostral whey with trypsin or chymotrypsin caused a progressive loss of the complement-mediated bactericidal activity of naturally-occurring colostral antibodies of E. coli 0111. Bactericidal activity was associated primarily with IgG1 immunoglobulin and to a lesser extent with IgM. Chymotrypsin preferentially attacked IgM, destroying its antibacterial activity and producing an apparent decrease in its mol wt. Trypsin preferentially attacked IgG1, but loss of antibacterial activity was in this case not accompanied by a decrease in molecular weight. Using colostral whey with antiperoxidase activity it was shown that the kinetics of loss of specific antibody activity were similar to those of loss of bactericidal activity. It is therefore suggested that trypsin may cause a loss of specific antibody activity of colostral IgG1 without cleaving the immunoglobulin molecule.

Animals↗
PubMed1977

The effect of limited proteolysis by trypsin and chymotrypsin on bovine colostral IgG1.

Limited proteolysis of bovine colostral IgG1 by trypsin caused loss of specific antibody activity but column chromatography showed that relatively little cleavage into fragements had occurred. Polyacrlamide-agarose SDS electrophoresis of the 2-mercaptoethanol-treated digest revealed, however, that extensive cleavage of light chains had occurred even though most of the material before reduction had a mol. wt close to that of undigested IgG1. Although a Fab-type fragment was detected in the digest by immunoelectrophoresis it appeared to be only a minor component. Chymotrypsin had little effect upon either the structure or antibody activity of IgG1. These findings may explain the effect of trypsin and chymotrypsin on the bactericidal activity of colostral antibodies.

Animals↗
PubMed1976

The effect of trypsin on bovine transferrin and lactoferrin.

The iron-saturated and iron-free (apo) forms of bovine transferrin and lactoferrin were digested with trypsin and the digests analysed by column chromatography and electrophoresis. Both of the iron-saturated proteins were more resistant to proteolysis than the corresponding apoproteins, and iron-transferrin was more resistant than iron-lactoferrin. Digestion of iron-transferrin yielded two iron-binding fragments with molecular weights of 32 000 and 38 500 whereas apotransferrin yielded only the larger fragment. In digests of lactoferrin, up to five different fragments with molecular weights ranging from 25 000 to 52 700 were detected, there being no obvious qualitative difference between digests of iron-lactoferrin and apolactoferrin. The susceptibility of apolactoferrin to tryptic digestion was only slightly reduced when apolactoferrin was complexed with beta-lactoglobulin, suggesting that complex-formation is not a mechanism for protecting lactoferrin against intestinal degradation. There was no immunological cross reaction between bovine transferrin or its digestion products against anti-lactoferrin antiserum, or vice-versa.

Animals↗
PubMed1976

An immunoenzymatic method for improving the sensitivity of antigen measurement by electroimmunodiffusion techniques. Application to the quantification of human alpha-fetoprotein.

A double antibody technique of electroimmunodiffusion, which uses glucose oxidase-labelled sheep antibodies to rabbit immunoglobulins as second antibody, is described. Primary antigen-antibody reaction is carried out with a rabbit antiserum by electroimmundiffusion. The glucose oxidase-labelled immunoreagent, being of general application, can serve for the quantification of different antigens and is here used for measurement of low levels of human alpha-fetoprotein. Reproducible results in the range of 50-800 ng/ml were obtained with a variation coefficient of 5 to 10%.

Animals↗
PubMed1975

Trypsin inhibitor from cow colostrum. Isolation, electrophoretic characterization and immunologic properties.

Trypsin inhibitor from cow colostrum has been purified by affinity chromatography of colostral proteins on insolubilized trypsin. The method described compares favourably, in both simplicity and yield, with previous methods developed for the isolation of this inhibitor. Gel electrophoresis followed by characterization of antitrypsin activity allows the demonstration of four molecular forms of bovine colostral trypsin inhibitor in both crude colostral whey and purified preparations of the inhibitor. Immunoelectrophoresis of each of these materials with antisera specific for this inhibitor reveals a single precipitation line of broad anodic mobility. By immunodiffusion tests, the precipitation lines in preparations of purified inhibitor and colostral whey appear immunologically identical. In contrast, absence of crossed reactivity was observed between bovine colostral trypsin inhibitor and trypsin inhibitors of bovine serum. This strongly suggests the high specificity of this inhibitor as a colostral and milk constituent.

Animals↗
PubMedDate not supplied

160Thr mutation in the rhodopsin gene associated with retinitis pigmentosa.

Mutations in the rhodopsin gene were studied in 23 unrelated Spanish patients with sporadic retinitis pigmentosa (RP). A codon 160 Thr C-->A transition was found in 4 of the 23 patients vs. none of the 159 controls (p < 0.001) suggesting that this mutation may be an informative marker in RP.

Exons↗
PubMedDate not supplied

Specific uptake of alpha-fetoprotein and albumin by rat Morris 7777 hepatoma cells.

Alpha-fetoprotein (AFP) is a major globulin of embryonic plasma and a physiological carrier of unesterified fatty acids. In the present work, we have characterized the interaction of AFP and albumin, a major serum protein of adult mammals which presents numerous biochemical analogies with AFP, with the plasma membrane of the rat Morris 7777 hepatoma cells. Time course analysis of the uptake of AFP and albumin by these cells showed a saturable profile at 4 degrees C and 37 degrees C. Saturable binding of 125I-AFP or 125I-albumin were observed when the concentration of these proteins increased (ranging from 0.3 to 4.5 microM). The Hill and Scatchard analysis revealed the existence of binding sites in the surface of hepatoma cells, with a k'd = 2.2 x 10(-6) M (2.9 x 10(6) sites/cell) in the case of AFP and a k'd = 4.5 x 10(-6) M (3.9 x 10(6) sites/cell) in the case of albumin. 125I-AFP and 125I-albumin bound to the cells were completely displaced in the presence of a 200-fold excess of unlabeled AFP or albumin, respectively, suggesting that these interactions were specific. We have observed crossed competition between AFP and albumin for their respective binding sites; no such crossed competition was observed when an excess of unlabeled transferrin was added. Pulse-chase experiments showed that about 50% of the AFP and 75% of the albumin taken up by the cells were released undegraded into the medium after 1 h. Cytochemical studies performed with covalent conjugates of AFP, albumin and transferrin with horseradish peroxidase have shown that AFP and albumin entered the cells via a vesicular system. This intracellular pathway is different from that of transferrin, a plasma protein whose internalization mediated by specific receptors via coated pits has been reported in other cells. The results presented here suggest that AFP and albumin interact with sites in the membrane of hepatoma cells, probably physically related, and then they are transported inside the cells by a mechanism different from that described for transferrin.

Animals↗
PubMedDate not supplied

[Plasmatic and erythrocytic zinc and copper levels in critically ill patients on parenteral nutrition and their relationship with formulas content: preliminary study].

OBJECTIVES: To study in severe patients that required parenteral nutrition the relationship between Zn and Cu amounts present in formulas, the clinical course and changes in some biochemical parameters (plasmatic and erythrocytic Zn and Cu levels) during the parenteral nutrition therapy. PATIENTS AND METHODOLOGY: Five adult severe patients were studied, submitted to major abdominal surgery, and that required parenteral nutrition. Determinations were done for: 1) Zinc and copper in parenteral formulas; 2) in patients, at the beginning (T0) and at the end (Tf) of treatment, in erythrocytes: zinc (Zn-E) and cupper (Cu-E); in plasma, zinc (Zn-Pl) and in serum, cupper (Cu-S). Zinc and cupper were determined by means of atomic absorbance spectrometry. RESULTS: mean +/- standard deviation values and ranges (between brackets) were: parenteral formulas (microg/g): zinc: 0.6 +/- 1.1 (2.2 - 7.0); Cupper: 2.4 +/- 0.7 (0.5-3.7). Biochemical parameters: at T0 (n = 5): Zn-E (microg/mL): 21.6 +/- 10.0 (13.6-36.1); Zn-Pl (microg/dL): 88 +/- 72 (29-205); Cu-E (microg/dL): 113 +/- 22 (60-102); Cu-E (microg/dL): 139 +/- 29 (106 +/- 156); Cu-S (microg/dL): 172 +/- 20 (158-195). Individual values compared to reference ones (normal individual from Buenos Aires with adequate nutrition) indicated that the three patients with favorable course normalized Zn-Pl and Zn-E levels. However, Cu-S increased in the three cases and Cu-E in two of them. CONCLUSIONS: These results make clear that in the studied patients Zinc levels in parenteral formulas would be adequate to prevent deficiency while Copper levels could be too high.

Adult↗
PubMedDate not supplied

Bactericidal and haemolytic activity of complement in bovine colostrum and serum: effect of proteolytic enzymes and ethylene glycol tetraacetic acid (EGTA).

Bovine colostral whey (CW) possessed heat-labile bactericidal activity against an enteropathogenic serum-susceptible strain of Escherichia coli. Activity was readily destroyed by trypsin or rat pancreatic juice, and less readily by chymotrypsin. Loss of activity due to trypsin, but not by chymotrypsin, could be prevented by addition of excess bovine colostral trypsin inhibitor. A second enteropathogenic strain of E. coli was killed by CW only if exogenous complement was added. This activity was maintained, however, even if the complement was heated 56 degrees C during 15 min. CW possessed only very weak haemolytic activity against sensitised rabbit erythrocytes, but could augment the haemolytic titre of bovine serum and could partially restore haemolytic activity to heat-inactivated bovine serum. These observations indicate that low but significant amounts of complement may occur in bovine colostrum. Sequestration of Ca++ by EGTA abolished all bactericidal and haemolytic activity in CW, and reduced but did not completely abolish these activities in bovine serum or in CW + exogenous complement. The activity of colostral complement therefore appears to be mediated entirely by the classical pathway whereas the alternate pathway may play some part in the bactericidal and haemolytic activities of bovine serum or of CW + exogenous complement.

Calcium↗