Résumé
Various quinolones have varied effects on the preservative activity of blood cells. Nalidixic acid causes hemolysis in G-6PD deficient patients where as ofloxacin has been found to possess preservative action of WBCs. The present study was undertaken to see the effect of various fluoroquinolones on RBC membrane. The effect of quinolones like ciprofloxacin, ofloxacin and norfloxacin and nalidixic acid in the dose of 5 micrograms/ml was studied on dapsone induced, in vitro hemolysis of rabbit RBC, using the osmotic fragility test. The mean corpusular fragility (MCF) with various agents were as follows: (mean +/- SE) saline; 5.23 +/- 0.21; dapsone, 6.57 +/- 0.23; ofloxacin, 3.81 +/- 0.13; ofloxacin and dapsone, 5.13 +/- 0.11; nalidixic acid, 6.28 +/- 0.16; nalidixic acid and dapsone, 6.65 +/- 0.13; ciprofloxacin, 3.52 +/- 0.22; ciprofloxacin and dapsone, 4.80 +/- 0.2; norfloxacin, 1.97 +/- 0.23; norfloxacin and dapsone, 4.27 +/- 0.20. The MCF data and shift of the osmotic fragility curves (to the left) show that dapsone induced erythrolysis is significantly protected by ciprofloxacin, ofloxacin and norfloxacin but not by nalidixic acid.
Sujets)
Animaux , Dapsone/toxicité , Hémolyse/effets des médicaments et des substances chimiques , Fragilité osmotique/effets des médicaments et des substances chimiques , Quinolinone/pharmacologie , LapinsRésumé
Pharmacokinetics of lithium was studied in 60 manic-depressive patients after an initial dose of 900 mg, in serial blood samples for 24 h. The values (mean +/- SD) obtained were peak serum Li concentration 0.81 +/- 0.18 mEq/l; time to peak 2.57 +/- 0.87 h; total Li clearance 33.2 +/- 15.5 ml/min; volume of distribution 0.62 +/- 0.26 l/kg; elimination rate constant 0.0514 +/- 0.02 h; area under serum concentration-time curve 16.41 +/- 11.41 mEq/1 h; serum half life 15.34 +/- 6.06 h. Thereafter, the applicability of various dose prediction methods was evaluated vis-a-vis the actual doses needed to attain steady state serum lithium concentration of 0.6-1.2 mEq/l in 46 patients. The method based on body weight was not found suitable. A nomographic method predicted higher doses in 27 patients, while Zetin's mathematical model predicted dose was in the range of +/- 150 mg of the actual dose in 21 patients. A method for predicting maintenance dose based on 24 h serum lithium level and body weight is suggested.
Sujets)
Adulte , Trouble bipolaire/métabolisme , Relation dose-effet des médicaments , Femelle , Humains , Lithium/sang , Mâle , Adulte d'âge moyen , Modèles biologiquesSujets)
Aconitine/administration et posologie , Aconitum/analogues et dérivés , Animaux , Troubles du rythme cardiaque/induit chimiquement , Pression sanguine/effets des médicaments et des substances chimiques , Cimétidine/pharmacologie , Chiens , Coeur/effets des médicaments et des substances chimiques , Rythme cardiaque/effets des médicaments et des substances chimiques , Injections ventriculaires , Propranolol/pharmacologie , Mépyramine/pharmacologie , Récepteurs histaminergiques/physiologieSujets)
Animaux , Bradycardie/induit chimiquement , Encéphale/effets des médicaments et des substances chimiques , Digoxine/toxicité , Chiens , Femelle , Rythme cardiaque/effets des médicaments et des substances chimiques , Mâle , Récepteurs cholinergiques/physiologie , Récepteurs histaminergiques/physiologie , Tachycardie/induit chimiquementSujets)
Aminopyridines/pharmacologie , Animaux , Fonction auriculaire , Cimétidine/pharmacologie , Femelle , Guanidines/pharmacologie , Cochons d'Inde , Coeur/physiologie , Atrium du coeur/effets des médicaments et des substances chimiques , Rythme cardiaque/effets des médicaments et des substances chimiques , Mâle , Mépyramine/pharmacologie , Récepteurs histaminergiques/physiologie , Récepteur histaminergique H1/physiologie , Récepteur histaminergique H2/physiologie , TempératureRésumé
Hydrocortisone (HC) injection in rabbits induced eosinopoenia (reduction in absolute eosinophil count) which could be successfully abolished by beta--adrenoceptor antagonists, a propranolol, sotalol, practolol and H 35/25 but not by alpha--adrenoceptor antagonist, phenoxybenzamine. Reserpine per se produced eosinopoenia followed by eosinophilia. However, reserpine pretreatment failed to abolish HC-induced eosinopoenia. It is suggested that the eosinopoenia is mediated through beta--adrenoceptors, which could not be differentiated into beta 1/beta 2--adrenoceptor subtypes as has been possible for other beta-adrenoceptor mediated responses.
Sujets)
Animaux , Granulocytes éosinophiles/effets des médicaments et des substances chimiques , Femelle , Hydrocortisone/antagonistes et inhibiteurs , Numération des leucocytes , Leucopénie/sang , Mâle , Lapins , Réserpine/pharmacologie , Sympatholytiques/pharmacologie , Facteurs tempsRésumé
Interaction of insulin with beta-adrenoceptor antagonists was studied in conscious rabbits. Propranolol and metoprolol did not modify the peak of insulin hypoglycaemia but delayed its recovery. Practolol, sotalol and 1-INPEA enhanced the peak effect and delayed the recovery of insulin-induced hypoglycaemia. H 35/25 and d-INPEA did not modify insulin hypoglycaemia. The beta-blockers did not produce significant hypoglycaemia per se. Since sotalol, 1-INPEA (specific beta-adrenoceptor antagonists devoid of local anaesthetic activity); practolol and metoprolol (selective cardiac beta-1 adrenoceptor antagonists) enhanced hypoglycaemic action of insulin and H 35/25 (a selective beta-2 adrenoceptor antagonist) failed to affect it, it seems that selective beta-adrenoceptor blockade (similar to cardiac beta-1 adrenoceptors) mediates enhancement of insulin hypoglycaemia. Caution should, therefore, be exercised in administering beta-adrenoceptor antagonists and insulin together. A reduction in the dose of insulin may be necessary.