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M Marois

Publications and source records attributed to M Marois.

114 records · Page 7Linked to original sources
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[Comparative action of an impeded estrogen, zeranol, and estradiol on some receptors in the female rat (author's transl)].

We have studied the estrogenic action of zeranol and have compared it to the action of estradiol on the uterus--the vagina, the mammary gland and the pituitary gland of the pre-pubescent, castrated female before the opening of the vagina. The weakest dose at which estradiol is active is 0.1 microgram injected for a period of three days : it is capable of opening the vagina on the fourth or fifth day and of developping the uterine glands to the maximum : injected over a period of ten days it provokes a hypertrophy of the pituitary gland : only the mammary gland reacts exclusively to doses other than physiological ones. The estrogenic action of zeranol is weak : 1 mg administered orally for three days is necessary in order to reproduce the same effects of 0,1 microgram of estradiol on the opening and the keratinisation of the vagina and on the stimulation of the uterine epithelium ; its efficacy is greater on the uterine glands (250 micrograms is equivalent to 0.1 microgram) and on the pituitary gland (500 microgram reproduce the hypertrophy provoked by 0,1 microgram). The doses administered are by 100 g of body weight. The uterine glands are more sensitive to stimulation by the estrogens employed (estradiol, zeranol) than is the uterine epithelium. The study of the relation between the estrogenic dose and the response of the uterine weight shows that the gradient of the curve is weaker with zeranol than with estradiol. This observation shows that zeranol behaves as an impeded estrogen.

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[On preclotting of woven Dacron vascular prostheses (author's transl)].

The role and the clinical value of common protocols of preclotting for a woven Dacron vascular prosthesis have been investigated. A comparative study of blood loss was carried out for Standard Woven De Bakey protheses inserted in a specially constructed extracorporeal blood circuit with canine models. The system detected transport of blood across the wall of the prostheses. These measurements were supplemented by gravimetric assessment of blood clot density and scanning electronmicroscopy examination of the internal surfaces of the prostheses. The pre-operative protocols investigated included : absence of pre-treatment, precoagulation with anticoagulant-free blood and various techniques using heparinized blood subsequent to an initial blood contact (modified method of Sauvage). The effect of using heparinized animals was also investigated. Leakages in unclotted prostheses could be reduced almost five fold by any precoagulation technique. Heparinization did not cause a significant increase in leakage and considerably improved the quality of the newly deposited blood product lining on the prostheses which consisted almost entirely of fibrin and eliminated any embolization.

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PubMedDate not supplied

[Glutaraldehyde - fixed human umbilical cord vein as a small diameter arterial substitute. Experimentation on the monkey].

Autologous saphenous veins, the preferred substitute material for aorto-coronary, femoro-popliteal and femoro-tibial by-pass, are usable in only 70% of individuals in need of such procedures. The development of small diameter substitute arteries is therefore essential to broaden the pool of patients who could benefit from this class of cardiovascular surgery. Existing substitutes, however, present major difficulties and have had limited success. In this laboratory, an attempt has been made to develop a vessel of 3 millimetres or less in diameter derived from human umbilical cord processed in glutaraldehyde. This substitute can be stored in 45% ethanol or dessicated by critical point drying. This device had been implanted as a segment of abdominal aorta in eight primates (Macaca fascicularis). Preliminary results are disappointing. The indicate that retention of a patency for more than a year post-implantation is difficultly achievable and that connective tissue hyperplasia leading to occlusion at the anastomoses is a major problem. Similar but larger diameter by-passes in the order of 6-8 millimetres should be investigated in greater detail, in order to better establish the "in-vivo" behavior of this class of tissue prosthesis. This would address the more fundamental issues pertaining to the clinical usefulness of fixed biological tissue by-pass devices.

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