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Biomedical subjects

D Lombardo

Publications and source records attributed to D Lombardo.

At least 109 records · Page 6Linked to original sources
PubMed1980

Studies on the substrate specificity of a carboxyl ester hydrolase from human pancreatic juice. I. Action on carboxyl esters, glycerides and phospholipids.

Purified carboxyl ester hydrolase (carboxylic-ester hydrolase, EC 3.1.1.1) from human pancreatic juice was found to hydrolyze triacetin, methyl butyrate and glycerides solubilized by bile salts. It has no activity on substrate presented as emulsoin or monomolecular films. The human enzyme was found to deacylate phospholipids and lysophospholipids at different rates. The hydrolysis of short-chain phosphatidylcholines was dependent of substrate solubility and dioctanoyl phosphatidylcholine was deacylated with the highest rate. Long-chain phosphatidylcholines and lysophosphatidylcholines present in microsomal membranes were deacylated with very low rates, only lysophosphatidylcholine deacylation was faster. Evidence is presented that human carboxyl ester hydrolase is the lyophosphatidyl-choline-hydrolyzing enzyme corresponding to bovine lysophospholipase. Bile salts play an important part on the activity of human carboxyl ester hydrolase, in addition to the role of detergent that they have on insoluble substrates.

Bile Acids and Salts↗
PubMed1980

Studies on the substrate specificity of a carboxyl ester hydrolase from human pancreatic juice. II. Action on cholesterol esters and lipid-soluble vitamin esters.

Evidence is presented that human carboxyl ester hydrolase (carboxylic-ester hydrolase, EC 3.1.1.1) is able to hydrolyze cholesterol esters and lipid-soluble vitamins A, D-3 and E esters. Those activities require the presence of bile salts and the 3 alpha, 7 alpha-dihydroxylated bile salts have been found the most efficient activators. The results presented in this paper and in the preceding one suggest the existence of two sites of bile salts recognition. One site, specific of the 3 alpha, 7 alpha-hydroxyl group of cholanic acid would induce dimerization and activation of the enzyme. The other site, unspecific towards bile salts hydroxylation would be located at the active center and would be implicated in substrate recognition.

Bile Acids and Salts↗
PubMed1980

Esterification of cholesterol and lipid-soluble vitamins by human pancreatic carboxyl ester hydrolase.

Human pancreatic carboxyl ester hydrolase is shown to catalyse the esterification of cholesterol and lipid-soluble vitamins A, E and D3 with oleic acid. The acitivity requires the presence of bile salts, and the trihydroxylated or the 3 alpha, 7 alpha dihydroxylated bile salts are better activators than the 3 alpha, 12 alpha dihydroxylated bile salts. The hydrolyzing and synthetizing activities of human pancreatic carboxyl ester hydrolase are separated by a large pH range since the synthesis of cholesterol esters is optimal at pH 5.25 and the hydrolysis of cholesterol and vitamin E esters is optimal at pH 8.0. From the comparison of the catalytic constants determined for the hydrolyzing and synthetizing activities and from the pH dependence of the two activities, it appears that human carboxyl ester hydrolase plays an important part in the intestinal lumen. The role of the enzyme in the esterification of cholesterol and lipid-soluble vitamins is questionable.

Bile Acids and Salts↗
PubMed1978

Purification and characterization of a carboxyl ester hydrolase from human pancreatic juice.

A carboxyl ester hydrolase has been purified 20-fold from human pancreatic juice. It is a glycoprotein with a molecular weight of 100 000. It contains 9% neutral and amino carbohydrates and the amino acid composition is characterized by a high content of proline residue (12.7%). The enzyme catalyzes the hydrolysis of p-nitrophenylacetate and the activity increases in the presence of biliary salts; V is not modified but Km is decreased 10 times by addition of biliary salts. The enzyme migrates on Sephadex G-200 as a protein with a molecular weight of 300 000. This behaviour does not seem to be due to a polymerization but to a peculiar configuration of the enzyme.

Amino Acids↗
PubMed1978

Two human trypsinogens. Purification, molecular properties, and N-terminal sequences.

The two human trypsinogens have been isolated from human pancreatic juice in a sufficient amount to study molecular and structural properties. The purification procedure included filtration on Sephadex G-100 followed by ion-exchange chromatography on DEAE-cellulose. The two trypsinogens represent 19% of total proteins of pancreatic juice. Trypsinogen 1, the major form, is present in a quantity twice that of trypsinogen 2, which is the most anionic protein in human pancreatic juice. The two proteins have partial immunological identity, close molecular weights (23 438 and 25 006 for trypsinogens 1 and 2, respectively) and similar amino acid compositions. The N-terminal sequences are the same for the first 9 residues: Ala-Pro-Phe-Asp4-Lys-Ile. The two proteins differ in the activation peptides released during the transformation to trypsins. Trypsinogen 2 liberates one octapeptide Ala-Pro-Phe-Asp4-Lys while trypsinogen 1 liberates two peptides, the same octapeptide and the pentapeptide (Asp)4-Lys.

Amino Acid Sequence↗
PubMed1977

[Necrosis of the pouch due to nontraumatic rupture of the pile during permanent endocardial electrostimulation].

Necrosis of the pouch containing the generator, due to non-traumatic breakage of the batteries, was observed in a patient with a permanent pacemaker, followed by rapid ingravescence. The cause of this complication is discussed. Chemical inflammation was noted soon after the pacemaker ceased to function. Initially this was similar to the not uncommon bacterial inflammation noted in such patients. Here, of course, the pacemaker usually continues to work, and its replacement is optional, whereas in the reported case is an emergency matter. In situations where tissue distress in the pouch is accompanied by inflammation, therefore, thought should be given to the possibility that, even if the batteries are still working, the cause may be chemical or electrochemical rather than septic, and than sudden breakdown of the generator may be expected.

Aged↗
PubMed1977

[The medico-social problem of rheumatic valve disease in Sicily].

The incidence of rheumatism and rheumatic valvulopathy in Sicily is assessed and the sites most commonly involved in the first and second attacks described. The medical aspects of te question are examined from several points of view: prophylaxis of sites, medical treatment personal and ambient hygiene, gradual defectiveness of the pump, associated diseases, etc. The concept of invalidity is viewed in terms of direct and associated anatomical damage and frank and potential invalidity (absolute or relative), the weight or assistance attributable to the family and the incidence of the local social environment in the question of finding work, etc. The basic criteria for surgery are noted. Care must be taken to preserve the few remaining structures. Mortality is still high and the incidence of heart disease is higher among rheumatic Sicilian children. Not enough is known about overcrowding, the schools attended by the poor, and the higher incidence in low-income classes. Failure to affront some of these features, determined as much by action (or its postponement) by government as by income, results in meaningless medicine, divorced from social reform and true the scientific spirit, a cover for special interests and a demonstration of profit factors wherein the commercialising relationship is increasingly evident.

Aortic Valve↗
PubMed1977

[Permanent endocardiac electrostimulation. Considerations on 511 implantations and reimplantations in 7 years of practice].

Permanent pacemakers were implanted and reimplanted in a total of 511 patients (mostly men) during a period of about 7 yr. Mean age was 67.9 yr. The cephalic route was used in nearly every case, with subclavicular implantation of the generator. Mean hospital stay was 7.6 days. Ventricular inhibition pacemakers were used in over 84% and fixed-frequency models in 7%. Mean pacemaker life was 24.1 months, with longer periods in the last months of the period of observation. The evaluation of battery run-down and recent and long-term complications is discussed, together with a particular type of decubitus of electrolytic origin. Hospital mortality was 2%. Survival was 91% at 1 yr and 54% at 6 yr. Emphasis is placed on the fact that subjects continue to be heart patients. Their well-being depends on psychological and general medical care, together with help from their, families and society, quite apart from cardiological attention.

Adult↗