Biomedical subjects

A M del Pozo

Publications and source records attributed to A M del Pozo.

7 recordsLinked to original sources

PubMed1992

Chronic ethanol abuse and membrane fluidity changes in liver disease.

The long-term effect of ethanol on human red cell membrane fluidity was studied, by fluorescence polarization with 1,6-diphenyl-1,3,5-hexatriene as a probe, in 11 healthy subjects, 9 chronic alcoholics without evidence of liver disease, 12 chronic alcoholics with biopsy-proven alcoholic liver disease and 9 abstemious patients with chronic active liver disease, most of them cirrhosis of the liver. Fluorescence polarization values were not significantly different in the two groups without liver disease. Patients with alcoholic and non-alcoholic liver disease showed higher fluorescence polarization values than patients without liver disease. These changes correlated with the severity of liver dysfunction and were not related to alcohol consumption. In conclusion, the decrease in fluidity of the erythrocyte membrane in alcoholic patients with chronic liver disease, is related to liver dysfunction but not to chronic ethanol ingestion. Changes in membrane fluidity in chronic alcoholics are found only in the presence of liver disease.

Adult↗

PubMed1986

Binding of 1-anilinonaphthalene-8-sulfonic acid to type I collagen.

The existence of a hydrophobic cluster on the COOH-telopeptides of type I collagen has been observed by studies on the binding of 1-anilinonaphthalene-8-sulfonic acid (ANS) to this protein. Collagen contains one binding site for the fluorescent probe. This hydrophobic cluster remains after pepsin digestion thus indicating that it is formed by the undegraded portions of the COOH-extrahelical ends of the protein. Energy transfer from tyrosine to ANS has been observed. The triple helix of collagen does not bind ANS.

Anilino Naphthalenesulfonates↗

PubMed1985

Interaction of type I collagen with sepiolite (magnesium silicate).

Type I collagen from calf skin interacts with magnesium silicate (sepiolite) resulting in a collagen-clay complex which is separated by centrifugation. The interaction primarily occurs with high molecular weight aggregates of the protein as indicated by the fact that collagen from the skin of lathyritic rats interacts to a lesser extent. Thus, when calf skin collagen is fully retained, 45% of protein from lathyritic animals remains in solution. Monomeric forms of collagen remain soluble after short periods of interaction with sepiolite; at 5 minutes, 34% of the calf skin collagen preparation is recovered in apparently monomeric form. In contrast protein-protein interaction produces the complete retention of the total collagen with longer periods of time.

Animals↗

PubMed1983

[Energy metabolism of Ehrlich ascites cancer cells].

Cell respiration (CR) and glycolysis (GL) are the main sources cell energy, since along their metabolic pathways ATP is produced. Expressed as microM/100 mg/h, normal cells produce 63 by CR, 0.2 by aerobic GL, and 9.37 by anaerobic GL, while cancer cells produce 35 by CR, 18 by aerobic GL, and 29 by anaerobic GL. The ascites fluid from EAC increases the anaerobic GL to 38, while it does not change the aerobic GL to 7 and diminishes the CR to 26. Insulin produces a lowering of CR to 26, aerobic GL to 26 and anaerobic GL to 22. Glucose inhibits CR and stimulates GL. Ribose does not modify CR and inhibits GL. Mannose inhibits both CR and GL. Ribonuclease increases GL in the presence of glucose but not of ribose. Glucose-phosphate and ribose-phosphate have no action because they do not enter into the cell. Expressed as QLN2/100 mg, the main localization of GL is the cytosol (480), but it is significant in the nucleus (170), and diminishes in microsomes (100) and mitochondria (52). Mitochondria inhibit the cytosol glycolytic activity when they are either in the usual proportion they have in the cell or in a higher proportion. It is curious the observation that a diminution of the relative concentration of mitochondria with regard to cytosol (1/100 to 1/1000) produces a marked increase of GL. The addition of nuclear fraction stabilizes the cytosol-mitochondria complex and modifies the metabolic pathway of the CO2 that is produced during the GL.

Animals↗

PubMed1982

[Method of isolation of cancer-associated and cancer-specific antigens].

Several biological and biochemical techniques are combined to get the isolation of tumor-specific and tumor-associated antigens (TSA and TAA). Specific antisera to plasma membrane TSA and TAA from the mouse Ehrlich ascites cancer (EAC) cells are induced by selective immunization of immunologic chimera rabbits to normal mouse antigens. The specific anti-cancer immunosera are absorbed with normal antigens to remove any possible residual normal antigens. The antibodies to TSA and TAA are purified by several cycles of discontinuous ascending chromatography in dextran gel particles, and used as a ligand for affinity chromatography in cyanide bromide-activated agarose gel. The material offered to the column consists of EAC cell plasma membrane fragments solubilized by ultrasonic waves, and isolated by discontinuous sucrose density gradient centrifugation. The marked cytotoxicity inhibition of antisera to EAC cells obtained by the TSA and TAA eluted from the affinity chromatography column, and the great immunogenicity of TSA and TAA in EAC-bearing animals show the existence of potent specific rejection antigens (TSRA and TARA) among the obtained TSA and TAA. The amount of TSA and TAA isolated from the EAC cell plasma membrane is 6 ng/10(6) cells, representing 1 part per 43,000 of the cell proteins.

Animals↗

PubMed1982

[Immunogenicity of cancer-associated and cancer-specific antigens].

The immunogenicity and anti-tumor activity of tumor-specific and tumor-associated antigens (TSA and TAA) isolated from the Ehrlich ascites cancer (EAC) cell plasma membrane is assayed, and compared with the action of several crude antigenic preparations. Control animals die 26 days after the EAC cells inoculation. Crude antigenic preparations produce a delay of EAC development, but all the animals finally die. The purified TSA and TAA are active at very small amounts, and inhibit completely and permanently the tumor development. The procedure shows a new approach to cancer specific active immunotherapy.

Animals↗

PubMed1982

Pigeon egg white lysozyme. Purification, structural and enzymic characterization.

Lysozyme from pigeon egg white has been purified by ion exchange chromatography and gel filtration. The overall yield of the purification procedure is 65%. The specific activity of the enzyme is 15 000 units/mg. The influence of pH and ionic strength on the lytic activity of the protein, as well as its thermal stability, have been studied. The molecular weight, secondary structure estimation, amino acid composition, NH2- and COOH-terminal sequence of the protein are also reported. The pigeon enzyme has been classified as a chicken type lysozyme (lysozyme c) according to the obtained results.

Amino Acids↗