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Biomedical subjects

M T Droy

Publications and source records attributed to M T Droy.

8 recordsLinked to original sources
PubMed1989

[Comparison of the effects of cicletanine and captopril on kidney and heart lesions in spontaneously hypertensive rats (SHR-SP)].

All studies carried out on stroke-prone spontaneously hypertensive rats (SHR-SP) have clearly demonstrated that cicletanine protects tissues and vessels. This effect has also been observed with captopril. However, the effectiveness of captopril seemed to be dependent on its blood pressure lowering effect, and this was not found with cicletanine in previous experimental studies on SHR-SP. In view of the difference in effectiveness between captopril and cicletanine as regards blood pressure, it was considered important to compare the two compounds in a similar blood pressure complex. In this study, the effects of cicletanine at two dosage levels (3.33 and 10 mg/kg/day) on the tissue and vascular lesions of SHR-SP were compared with those of captopril in doses of 1 mg/kg/day. Iffa Credo SHR-SP rats aged 7 weeks were divided into four groups of 12 animals each: 2 groups received cicletanine 3.33 and 10 mg/kg/day respectively, 1 group received captopril 1 mg/kg/day and 1 group served as control. Blood pressure was recorded once a week. After 44 days of treatment, all animals were killed and autopsied. A significant antihypertensive effect was observed with both captopril (p less than 0.001) and cicletanine 10 mg/kg (p less than 0.05). In doses of 3.33 mg/kg cicletanine induced only a very slight fall in blood pressure, not significantly different from controls. On the other hand, histological and ultrastructural examinations showed better preservation of tissues and, chiefly, vessels with cicletanine at the two dosage levels than with captopril 1 mg/kg.

Animals↗
PubMed1989

[Protective effect of cicletanine in hypertensive retinopathy. Evaluation of retinal function in the isolated retina].

In order to demonstrate functional impairments related to hypertensive retinopathy, we experimented on the isolated retina of spontaneously hypertensive rats (SHR-SP strain A3N Iffa Credo). We also used this experimental model to assess the protective effect of treatment with cicletanine, a new synthetic furopyridine compound. Treatment consisted of daily oral administration of either 50 or 100 mg/kg of cicletanine for 5 weeks. Retinal function was evaluated by recording the electroretinogram (ERG) obtained in response to light stimulation (300 lux, 1 ms) of the isolated retina maintained in survival by perfusion. The results indicate: (i) that ERG amplitude remains systematically lower in hypertensive rats than in normotensive rats and that in consequence retina survival is shortened; (ii) that in cicletanine-treated hypertensive rats ERG amplitude is significantly higher than in untreated hypertensive rats, the drug augmenting the duration of retina survival. Although cicletanine significantly improved the ERG amplitude obtained in hypertensive rats, this amplitude was still lower than in normotensive rats. These results are consistent with those of previous histological studies performed on the same of hypertensive rats, which demonstrated that impairments of retinal capillaries, photoreceptors and ganglion cells may have deleterious functional consequences for the visual process. Cicletanine is able to reduce these histological impairments, and the present study demonstrate that the drug can also significantly improve the ERG amplitude.

Animals↗
PubMed1989

[Effects of cicletanine on kidney lesions associated with age. Light and electron microscopy studies].

Aging laboratory animals constantly present with chronic progressive nephrosis. The purpose of this study was to investigate the protective effect of a chronic treatment with cicletanine in aging rats, notably as regards kidneys. Sixteen Wistar rats aged 26 months were divided into two groups: one group served as control, while the other received oral cicletanine 30 mg/kg/day. Blood pressure, weight and death rate were recorded. No rise of arterial pressure was observed in either group. The rats were killed on day 151, i.e. aged 31 months, after 5 months of treatment. All were autopsied and their kidneys, heart, lungs, liver, brain and eyes were removed for examination. Light microscopy of the renal tissue showed the lesions described in the chronic progressive nephrosis of the aging rat. These lesions were diffuse and pronounced in the control group and minimal in treated rats. The difference was confirmed by electron microscopy. The basal membrane of renal tubules was slightly thickened in the treated rats and two or three times thicker in control rats. Mitochondrial alterations were observed in the proximal tubules of controls but not in those of rats treated with cicletanine. Thus, after a 5-months treatment with cicletanine aging Wistar rats well known for their renal pathology were protected against kidney lesions in contrast with untreated rats.

Aging↗
PubMed1985

[Effects of oxygenated free radicals on the electrophysiological activity of the isolated retina of the rat].

Particularly rich in polyunsaturated fatty acids, the retina constitutes an excellent model for testing the functional consequences of membrane lipoperoxidation. The effects could be quantified by measuring the amplitude of the electroretinogram which represents the characteristic response of the retina to its physiological stimulus (light photons). The authors report results obtained on isolated rat retina maintained in survival by perfusion. The membrane lipid peroxidation is induced by the non enzymatic catalytic system (Fe2+ + ascorbate). In the presence of such a system, the amplitude of the b-wave of the electroretinogram rapidly decreases and the survival time is notably shortened. These results are discussed with regards to the mechanism generating the electroretinogram and the specific role played by the disk membrane and plasmic membrane of the rod outer segment. Finally, the authors test the radical scavenger properties of a Ginkgo biloba extract. The results indicate that such an extract develops an antiperoxidative effect probably connected with its flavonoid composition. With this extract the survival time of the isolated retina is significantly increased and this result could be related to the retinal cell membrane disorders observed in diabetes.

Animals↗
PubMed1982

[Regeneration of peripheral nerve (author's transl)].

The authors make an attempt of dating up our knowledge of the functions which interfere with the peripheral nerves regeneration after an injury by a traumatism or an another pathological cause. The lesion of a nerve fiber causes changes on the cellular body, on the distal segment and on the glial environment. The regeneration which is a physiological phenomenon, is conditioned by the importance of the injury and the location of the injury. The regeneration require an important increase of the protein synthesis, specially the cytoskeleton proteins. This cytoskeleton is essential for the maintenance of axonal transports which control the arrival of materials requested for the fiber growth and for its functional recovery.

Animals↗