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Biomedical subjects

R J Royer

Publications and source records attributed to R J Royer.

107 records · Page 6Linked to original sources
PubMedDate not supplied

[Evaluation of venotropic drugs by venous gas plethysmography. A study of procyanidolic oligomers (author's transl)].

Venous tone in the lower limbs can be measured by venous occlusion gas plethysmography before and after giving venotropic drugs. Four groups, each of which included ten patients with widespread varicose veins, were given different medications. Each patient was studied by plethysmography during the first five hours following drug ingestion. In untreated controls, venous tone decreased during rest. A reference drug was uneffective. Increase in venous tone induced by 150 mg of procyanidolic oligomers was comparable to that which followed ingestion of a high dose of hamamelis-hydrastis mixture.

Benzopyrans↗
PubMedDate not supplied

[Toxicity and pharmacokinetics of zirconium oxychloride in mice and rats].

The experimental toxicity of zirconium compounds is examined in the Mouse (acute toxicity) and in the Rat (short time toxicity). The absorption, the distribution and the elimination of zirconium are evaluated by zirconium cation assay in some biological fluids and tissues. After a single oral dose, zirconium oxyd is not toxic, zirconium oxychlorure slightly toxic and zirconium chlorure moderately toxic. At certain concentrations, cerebral and pulmonary disorders are observed, particularly with zirconium chlorure. In considering molar toxicity, the studied zirconium compounds are more toxic than certain aluminium salts mentioned in the literature. The zirconium oxychlorure doesn't influence the growth curve after iterative administrations (0.23 g zirconium/kg/day). Only a weak fraction of administered zirconium is absorbed and is electively fixed in the ovaries, in a lesser degree in the lung and the bone. In the ovary the zirconium induces vascular variation (hypervascularization) which appear one month after the end of the treatment. The absorbed zirconium is eliminated by the urinary tract. The fecal elimination can be essentially explained by an important quantity of non absorbed zirconium.

Animals↗
PubMedDate not supplied

[Stereoselective protein binding of non-steroidal anti-inflammatory agents. Pharmacological implications].

Non steroidal anti-inflammatory drugs (NSAIDs) contain a chiral carbon alpha to carboxyl function. Except for naproxen, chiral NSAIDs are marketed for clinical use as racemate, ie an equimolar mixture of the two enantiomers R(-) and S(+). However, in vitro studies have shown that the anti-inflammatory activity exists almost solely in the S form. The unbound fraction is able to diffuse into tissues and to reach sites of action. It represents also the pharmacological active form. Stereoselective protein binding studies carried out at various concentrations of NSAIDs and albumin are used to evaluate the free fraction of the active enantiomer. Two optical isomers do not interact in the same manner with proteins and this binding stereoselectivity depends on NSAID and experimental conditions. Thus, it seems difficult to predict the in vivo free concentration of each enantiomer and protein binding experiments should be achieved taking into account the physiopathological parameters which influence this biological process. This enantioselectivity is determinant for the pharmacokinetic properties and could be responsible of the parameters variation obtained for each enantiomer. It could explain the variability in response to NSAIDs too. In fact, the anti-inflammatory effect is directly function of the free concentration of the S isomer. To correlate the NSAID dose with its activity, it should be better to determine this free fraction in the site of action, in particular in the synovial fluid. But the clinical response, as for example the antalgic effect, remains very far from the pharmacological activity, ie the cyclooxygenase inhibition.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMedDate not supplied

Adverse drug reactions with fluoroquinolones.

The French system of drug surveillance has analysed the notifications of adverse drug reactions (ADRs) to fluoroquinolones since they were launched. Their frequency ranges from 1/15,000 to 1/208,000 case per days of treatment. Cutaneous diseases and tendon disorders predominate in France whereas cutaneous effects and neuropsychiatric disorders are predominant in the UK; tendon disorders take up only the 5th position. Among the most unexpected ADRs are the following: -shock represents 33 of the anaphylaxis reactions which range from 1/5.6 x 10(6) to 1/4.4 x 10(5) case per days of treatment. -acute renal failure is rare: one case/80,000 patients treated by ciprofloxacin to 1/320,000 by norfloxacin. The pathophysiology is not well known. Tendon ruptures represent 81 cases for 921 notifications of tendon disorders which are related in decreasing order to pefloxacin 1/23,130 case per days of treatment, ofloxacin, norfloxacin and ciprofloxacin 1/779,600 case per days of treatment. Age and corticosteroids increase the risk of tendon rupture.

Adverse Drug Reaction Reporting Systems↗