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Biomedical subjects

A Bertelli

Publications and source records attributed to A Bertelli.

At least 127 records · Page 7Linked to original sources
PubMed1983

Mast cell histamine release induced by doxorubicin and the inhibitory effect of fructose 1,6-diphosphate.

Doxorubicin (DXR) (10(-4) mol/l) causes histamine release from isolated rat mast cells. At lower doses (range 10(-8) mol/l-10(-5) mol/l) the drug failed to evoke secretion. In the 10(-5) mol/l-10(-4) mol/l range there is a significant decrease of the ATP intracellular levels. Fructose 1,6-diphosphate (FDP) produced a sharp increase of the ATP content of the DXR treated cells. In particular, FDP pretreatment inhibited the DXR stimulated histamine release.

Adenosine Triphosphate↗
PubMed1983

Distribution of inhaled mercury (203Hg) in various organs.

Mercury and its derivatives have long been known to be toxic for the brain and other organs in both animals and man. The distribution of inhaled radioactive mercury (203Hg) in body tissues of rats and mice was investigated by means of a micro-autoradiographic technique. Animals were exposed to 203Hg vapours 6 h daily for 10 days, and then sacrificed at different times after the last exposure. Whole-body autoradiograms showed significant uptake of labelled mercury by the kidney, brain, myocardium, intestine and liver, in decreasing order. Micro-autoradiography demonstrated selective localization of 203Hg in the cytoplasm and processes of neurons, whereas little radioactivity was found in the glial cells of the gray and white matter. High levels of 203Hg were detected in nuclei of the cerebellum, midbrain, pons and medulla, in the Purkinje cells of the cerebellar cortex, and in the epithelium of the ependyma and choroid plexus. In the lung, radioactivity appeared to be confined to the erythrocytes of small blood vessels, which may be the carriers of this metal to the brain. In the liver, ingested but not inhaled radioactivity was concentrated in the reticulo-endothelium. In the kidney, proximal and distal convoluted tubules, but not the medulla or the glomeruli, took up large amounts of inhaled 203Hg. Mercury is distributed to many organs in addition to the brain. It may be transported by circulating red blood cells and it concentrates in the cytoplasm of parenchymal cells.

Animals↗
PubMed1983

The pharmacokinetics of clofoctol in healthy neonates and adults studied by an original HPLC technique.

The pharmacokinetics of clofoctol [(tetramethyl-1,1,3,3,butyl)-4-(dichloro-2,4-benzyl)-2-hydroxy-1-benzene ] was investigated in six healthy newborns and compared with the kinetic parameters of the drug in six healthy adults. The concentration of the drug in plasma was measured by means of an original sensitive HPLC technique. In both neonates and adults treated rectally with clofoctol, the plasmatic peak occurred at the 30th min, although the maximal peak of adults was significantly lower. Kel and T1/2 exhibited a similar pattern, whereas the AUC was about 5 times higher in newborns. The present findings suggest that clofoctol is well absorbed rectally. The higher plasmatic levels of clofoctol in neonates may result from their lower degree of hepatic metabolic activity.

Adult↗
PubMed1983

Pharmacokinetics and bioavailability of metergoline in healthy volunteers after single i.v. and oral administration.

Concentrations of unchanged metergoline and its main metabolite, 1-demethylmetergoline, were measured by HPLC and fluorescence detector in the plasma of 13 healthy male volunteers. The subjects received on various occasions the following single-dose metergoline treatments: 4 mg by i.v. infusion (n = 7), 8 mg orally as aqueous solution (n = 7) and 8 mg orally as two different formulations of film-coated tablets (Formulation A, n = 12; Formulation B, n = 12). The mean plasma t 1/2 of metergoline and of 1-demethylmetergoline were about 50 min and 100 min, respectively, independent of the route of administration. A considerable first-pass effect was evident from the data, with about 75% of metergoline being metabolized by the liver before reaching the systemic circulation. However, the availability of the drug in terms of 1-demethylmetergoline was similar for the i.v. and oral routes of administration indicating a complete absorption of the solution from the gastrointestinal tract. Very low plasma levels of another metabolite (12-hydroxymetergoline) were detected in some patients. The bioavailability of film-coated tablets in Formulation B was slightly better than for Formulation A with regard to both relative absorption (A vs B = 82%) and lower interpatient variation. Compared with oral solution, the absorption of Formulation B was slightly slower but practically complete.

Administration, Oral↗
PubMed1981

D-penicillamine induced changes on rat mast cell cyclic GMP levels.

The cGMP accumulation in rat serosal mast cells was measured after cell treatment with D-penicillamine, a sulphydryl containing compound. Preincubating the cells with increasing doses of the drug causes a decrease of basal level of the nucleotide. In cells activated with the degranulating agent 48/80 there is a sharp increase in cGMP intracellular levels. D-Penicillamine prevents the nucleotide accumulation caused by compound 48/80, decreasing even the steady-state level in activated cells. The effect on cGMP metabolism does not correspond to an inhibition of histamine release.

Animals↗
PubMed1981

The pharmacokinetics of two erythromycin esters in plasma and in saliva following oral administration in humans.

An improved highly sensitive fluorimetric methods has been employed to measure plasma and saliva levels of erythromycin propionate and stearate in eight healthy volunteers following a single oral dose of 7.5 mg/kg. The plasma curves exhibited a mean half-life of 5.22 +/- s. e. m., 0.86 h-1 for the propionate and 2.97 +/- 0.22 h-1 for the stearate. Peak levels were reached at the 2nd h (4.07 +/- 0.29 microgram/ml for the propionate; 2.15 +/- 0.14 microgram/ml for the stearate). The area under the total plasma concentration curve was about 3-fold higher in the case of propionate. The concentration in saliva was about 20% of the corresponding concentration in plasma for the propionate and about 25% for the stearate. A significant positive correlation was observed between plasma and saliva levels for both macrolides.

Administration, Oral↗
PubMed1979

Polymyxin B-induced oedema in hind paw of the rat as an assay for antiinflammatory drugs.

A method is presented for measuring the volume of the oedema induced by intraplantar infection of polymyxin B, a polyenic antibiotic, in the hind paw of the rat. Peak values of the oedema reached the maximum within 30 min to 1 h after injecting the drug and decreased with time until the 24th h, when it had almost disappeared. The phlogogenic effect of polymyxin B seems to be related to that induced by serotonin and histamine, rather than to the reaction provoked by carrageenin or prostaglandins. The oedema was inhibited by pretreating the animals p.o. with both steroidal and non-steroidal antiinflammatory agents. The inhibitory effect of antiinflammatory drugs was found to be dose-dependent.

Animals↗
PubMed1979

Activity of tolmetin on levels of cyclic nucleotides in experimental pleurisy.

Experimental pleurisy induced in rats with an intrapleural injection of 0.2 ml of 2% acetic acid, was used to test the effect of some non-steroidal anti-inflammatory drugs. During the acute phlogistic reaction there is a variation of the cAMP/cGMP ratio, with a sharp increase of the cGMP concentration and a parallel decrease of the cAMP level in the exudate. Indometacin and 1-methyl-5-p-toluoylpyrrole-2-acetic acid (tolmetin, Tolectin), two non-steroidal anti-inflammatory drugs, injected intrapleurally 1 h before the acetic acid injection were able to reduce the inflammatory response, affecting the cAMP and cGMP ratio. That is there is an increase of the cAMP level and a decrease of the cGMP level.

Acetates↗
PubMed1977

Effects of dibenzothioline and silymarin on the dry weight of isolated hepatocytes of rats acutely poisoned with phalloidin and alpha-amanitin.

The protective action of dibenzothioline and silymarin in the acute intoxication by phalloidin and alpha-amanitin has been studied on the basis of their ability to attenuate changes in dry mass distribution and class-pattern of the hepatocytes, as evaluated by microinterferometry. Protective agents were given to male rats 30 min before toxin, and the animals were sacrificed 3.0 h later. Both dibenzothioline and silymarin markedly counteract the toxic action of phalloidin and alpha-amanitin on the hepatocyte population, as revealed by a substantial prevention (a) of the striking displacement of hepatocytes in the intervals among the classes as regards phalloidin poisoning, and (b) of the number decrease of hepatocyte classes due to disappearance of the heaviest ones, of the shift of hepatocytes to the lighter classes, of the appearance of very light cells, of the displacement of hepatocytes into the class intervals and of the decrease in nuclear dry mass as regards alpha-amanitin. It is suggested that dibenzothioline and silymarin exert their protective action by a non-specific stabilization of the cell membrane.

Amanitins↗
PubMed1976

[Effect of silymarin on the total dry mass of hepatocytes inacute poisoning by phalloidin and alpha-amanitine (author's transl)].

The effects of silymarin on the total dry mass and class pattern of rat hepatocytes have been studied during acute poisoning by phalloidin and alpha-amanitine. Phalloidin (2/5 of the LD50) after 3 h causes a marked change in the hepatocyte class pattern due to a displacement of a high percentage of cells in the intervals among classes, while the cell dry mass increases slightly. alpha-Amanitine (1/4 or 1/2 of the LD50) after 3 h causes a decrease in the number of classes of hepatocytes due to a disappearance of the heavier ones, a displacement of cells in the intervals among classes, an appearance of very light cells, and a decrease by about 25% in the mean dry mass of the hepatocytes. Silymarin, administered 30 min before poisoning, prevents all the changes due to 2/5 of the LD50 of phalloidin and to 1/4 of the LD50 of alpha-amanitine, and strongly reduces the effects of 1/2 of the LD50 of alpha-amanitine. The effects of alpha-amanitine and phalloidin and the protective action of silymarin on the dry mass and class pattern of hepatocytes are discussed.

Amanitins↗