1,721,022 research outputs found
Metabolic Fate of Partially Depolymerized Shark Chondroitin Sulfate in Man
No full textChondroitin sulfates and other glycosaminoglycans are administered as drugs to man by intravenous, intramuscular or oral routes. There are some studies on the pharmacokinetics of heparin, heparan sulfate and dermatan sulfate, whereas few data are available on the metabolic fate of chondroitin sulfate in man. Partially depolymerized chondroitin sulfate (mean mol. wt: 7.5 kd, range 5-10 kd) with a ratio of 1:3 between chondroitin-4-sulfate and chondroitin-6-sulfate has been administered as single administrations of 0.2 and 1.2 g by intramuscular and oral routes respectively to 10 healthy volunteers (5 males and 5 females), aging 25-53 years. After intramuscular administration the plasma level increased to a concentration peak at 90 min. The peak concentration, the elimination half-life and the apparent distribution volume were respectively 3.8 mcg/ml, 275 min and 0.40 ml/g. About 37% of the administered chondroitin sulfate is excreted in the urine during the first 24 h as high- and low-molecular-weight derivatives. After oral administration the concentration peak was observed at 240 min. The concentration at the peak, the elimination half-life and the apparent distribution volume were respectively 4.6 mcg/ml, 310 min and 0.44 ml/g. A peak of mono-, oligo- and polysaccharides with a molecular weight lower than 5 kd derived from partial digestion of exogenous chondroitin sulfate is also present in plasma. This study shows that about 10% and 20% of the orally administered drug is absorbed as high- and low-molecular-weight derivatives respectively. Comparison with the results obtained in experimental animals indicate that the metabolic fate of partially depolymerized chondroitin sulfate is similar in man and in experimental animals
Metabolizzazione della 4-Carbometossitiazolidina Cloridrato a Cisteina ad Opera di Espettorati ed Omogenati di Polmone Umani e sua Azione sulle Glicoproteine del Muco
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Recent Findings on the Regulatory Function of CoA and on the Normalizing Activity on Plasma Lipids of Exogenous CoA
No full textIn recent years many studies have shown that coenzyme A (CoA) is not only an acyl carrier coenzyme but it also has an important role in the regulation of metabolic functions and cell activities such as transport from the Golgi cisternae. This regulatory role is carried out by CoA, its precursor, catabolites and acylated derivatives. The acylation (myristylation and palmitylation) process of peptides and proteins dependent on CoA seems to be an important regulatory mechanism of cell activities. Furthermore exogenous CoA has been shown to decrease the triacylglycerols, cholesterol and Apo B of plasma lipoproteins in man. This regulatory mechanism acts either on VLDL synthesis and secretion or on their plasma clearance. CoA also protects cell-membrane and plasma lipoproteins against the peroxidative action of oxygen free-radicals
Absorption and Excretion in the Experimental Animal of a l4C-Ethylmaleimide Labelled Peptide Fraction of Bovine Factor VIII with Antihaemorrhagic Activity
No full textIn this study the absorption and excretion of a peptide fraction from bovine Factor VIII (Vueffe) with antihaemorrhagic activity were investigated in rats and rabbits. The results obtained suggest that the peptide fraction may be absorbed from the gastrointestinal tract through an active transport or a process of nonselective pinocytosis. The radioactivity elimination was rapid and almost complete within 24 h. In addition no difference was observed between single or repeated dosing in the pharmacokinetic parameters. The evidence following routes of administration shows the good bioavailability of this peptide fraction of low molecular weight and confirms the efficacy after oral administration at very low doses
Farmacocinetica, Biotrasformazione e Distribuzione di un Nuovo Antinfiammatorio non Steroideo
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Metabolic Fate of Exogenous Chondroitin Sulfate in the Experimental Animal
No full textAfter the administration of tritiated chondroitin sulfate (CS) by oral and intramuscular route, the distribution of radioactivity was investigated in two opportunist omnivorous animals, namely the rat and the dog. More than 70% of the orally administered radioactivity was absorbed. Independently of the administration route, radioactivity was mainly excreted through the urine. Plasma levels showed a rapid increase after oral administration, followed by a large plateau with a maximum at the 14th and 28th h in the rat and in the dog, respectively. A tropism of the radioactivity was observed towards glycosaminoglycan-rich tissues, such as joint cartilage. The analysis of the molecular weight of the radioactive material showed that compounds with a molecular weight corresponding to those of CS, poly-, oligo- and monosaccharides as well as of tritiated water, were present in the plasma, urine, synovial fluid and cartilage. The level of radioactive low molecular weight material, derived from the metabolism of CS and from the exchange reaction, increased with the time after administration. The high molecular weight fraction represented at least 10% of the orally administered CS
Antidyslipaemic Action and Role of CoA in Lipid Metabolism of Mitochondria and Peroxisomes
No full textOur study has evaluated the effect of the parenteral administration of CoA on the pattern of haematic lipids and on palmitate oxidation in liver mitochondria and peroxisomes of rats made hyperlipaemic with a high fat diet with or without CoA. Lipid fractions, total cholesterol, triacylglycerols, total lipids and nonesterified fatty acids (NEFA) were determined in blood. Palmitate oxidation was determined in liver peroxisomes and mitochondria incubated in modified Krebs-Henseleit solution with 100 microM 1-14C palmitate in the presence and absence of some cofactors. Our results show that in rats fed with a high fat diet there was an increase of all lipid fractions. The increase of all lipid components was lower in animals treated with CoA. In liver peroxisomes of rats fed with high fat diet an increase in palmitate oxidation, that is higher when CoA is parenterally administered, was observed. In addition, palmitate oxidation in mitochondria of rats treated with CoA reached values higher than those of control and of rats fed with a high fat diet without CoA
Effect of chain length and aldehydic function on some biological properties of parropolyenes
No full textParropolyenes, also called parroenes, parrodienes and psittacofulvines, are aldehydes costituted of an unsaturated chain ranging from 8 to 18 carbon atoms. These compounds have been isolated from the plumage of parrots and are also synthesized in the laboratory. Parropolyenes have antiproliferative and antioxidant activities. We investigated the effect of chain length and the role of aldehydic function of some parropolyenes by comparing their biological activities with those of their corresponding alcohols. Trans, trans-Δ2,4-hexadienal at a concentration of 100 μM significantly inhibited the growth of SH-SY5Y cells after 72 h of incubation. The corresponding alcohol was less effective. All-trans-Δ2,4,6-octatrienal and all-trans-Δ2,4,6,8,10-dodecapentaenal were more effective since significant inhibition of growth was observed at a concentration of 10 μM. Again, the corresponding alcohols were less effective. All-trans-Δ2,4,6-octatrienal and all-trans-Δ2,4,6,8,10-dodecapentaenal at 1 μM concentration protected 2-deoxyribose from degradation by ferrous ions. Trans, trans-Δ2,4-hexadienal at the same concentration does not show this protective effect. The protection increased with increasing parropolyene chain length. No significant difference was observed between aldehydes and their corresponding alcohols. Parropolyenes increased the rate of lysis of erythrocyte membrane in a lactoperoxidase-potassium iodide-hydrogen peroxide assay. The cytolytic effect increased with increasing parropolyene chain length. In this assay no difference was observed between aldehydes and alcohols. In all assays the effects were concentration dependent
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