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Biomedical subjects

R Masse

Publications and source records attributed to R Masse.

At least 109 records · Page 6Linked to original sources
PubMed1980

Mesothelioma induced by intrapleural injection of different types of fibres in rats; synergistic effect of other carcinogens.

Intrapleural injections of 20 mg of various mineral fibres were made to rats. Three types of fibres (chrysotile, crocidolite and glass fibres) were untreated; other chrysotile fibres were leached to different degrees. The results show that chrysotile is the most toxic of the three: animals died sooner and presented mesotheliomas earlier. With increased leaching, toxicity and carcinogenic effect decreased. Crocidolite is less toxic than untreated chrysotile but later produces as many mesotheliomas; with glass fibres, some mesotheliomas are observed. Small groups of animals were exposed to two types of irradiation before intrapleural injection of 2 mg of chrysotile. Whole-body irradiation was delivered to a third group of animals which were given asbestos-contaminated food. The paper analyses the synergistic action of these two insults.

Animals↗
PubMed1980

Experimental demonstration of the penetration of asbestos fibres into the gastrointestinal tract.

Evidence for a no-threshold concentration-effect relationship for many environmental carcinogens, and especially for asbestos fibres, has been substantiated. Thus, the risk for humans of low concentrations of fibres in the diet could be predicted if the absorption of fibres through the gut could be measured. In this study, the behaviour of ingested fibres (asbestos and attapulgite) has been investigated by the collection of lymph, as described by Bollman et al. (1948). Fibres were found to cross the gut wall and to circulate in the abdominal lymph at 2-24 hours after feeding. The kinetics of the fibre passage could be measured: 50% of the total load absorbed was found in the lymph within the first six hours. The greatest fibre passage was observed with long asbestos fibres, which reached 2.1 X 10(-4) of the ingested load. Selection of the longest fibres was observed when size distributions were compared in the lymph and in the diet. negative results were obtained consistently in controls and in some of the treated animals. Lymph collection was found to be the most appropriate method for detecting intestinal absorption.

Animals↗
PubMed1980

Biochemical and anatomical study of collagen and associated macromolecules in pulmonary panacinar emphysema and spontaneous pneumothorax.

In collagen content of four emphysematous lungs as defined by radiological, physiological and anatomical tests were studied. They were compared to three control lungs and five lungs removed from patients with relapsing pneumothorax (PNO). Morphologically, emphysematous lungs were characterized by patchy disorganization of collagen fibers, involving microfibrillar areas or elastoid laminae. Elastic fibers were at times found in plugs. Such abnormalities were also present, but less frequently in the PNO group. Biochemically, emphysematous lungs showed an increase of soluble proteins removed by CaCl2 extraction, which were associated with a decrease in insoluble proteins in extracted by TCA. Total hydroxyproline, expressed as a fraction of deoxyribonucleic acid (DNA) content, was not modified, but an increase of dialyzable and undialyzable fraction was observed in MEM medium. The PNO group showed the same modifications in terms of mean values, but individual results were more scattered. Results of in vitro 14C-proline incorporation did not show any modification of collagen biosynthesis, except in 2 emphysematous lungs. The results indicate that the PNO group is nearer to the emphysematous group than the controls. This suggests that patients with relapsing PNO may develop emphysema but it has to be further substantiated. The results here presented indicate that soluble hydroxyproline is an index either of abnormal synthesis or of excessive collagenolysis.

Collagen↗
PubMed1979

[Leukocyte migration toward the alveoli].

Migratory processes of leukocytes toward alveolus have been studied after intratracheal injection of aluminium or beryllium hydroxide. Migrating cells could only be observed during the first three days following the injection. Three migrating processes were pointed out and especially an emperipolesis phenomenon. This morphological observation and cytokinetic study of septal cells, exclude the existence of a precursor septal pool involved in a maturation process of alveolar macrophages.

Aluminum Hydroxide↗
PubMed1979

Experimental modifications induced by membrane oxygenators on lung ultrastructure in dogs and baboons.

Extracorporeal circulation with membrane oxygenator (E.C.M.O.) was performed in 6 dogs and 5 baboons during 4 to 57 hours. Examination of pulmonary samples showed progressive lesions in the two species: at the second hour of E.C., alteration of capillary endothelium, at the sixth, extensive lesions of all the lung structures, worsening later on. We discussed whether these lesions are related to the E.C.M.O., their reversibility and the questionable benefit of E.C.M.O. for management of respiratory distress syndrome.

Animals↗
PubMed1978

[Renewal of pulmonary insoluble collagen in the adult rat].

Study of polymeric pulmonary collagen in adult Rats showed that about 70% of collagen was renewed with a half-time equal to 525 days. This value is to be compared with the median life-span of this rat strain, 890 days. The remaining 30% of polymeric collagen is renewed with a shorter half time, about 30 days.

Age Factors↗
PubMed1977

Studies of bone and soft-tissue tumours induced in rats with radioactive cerium chloride.

A colloidal suspension of radioactive cerium chloride was inoculated into the hind legs of Sprague Dawley rats. Bone and soft-tissue tumours were induced at the site of inoculation in 77% of the animals. All bone tumours were osteogenic osteosarcomas. Soft tissue tumours were mostly malignant and were of various histological types, predominantly fibrosarcomas, haemangiopericytomas, angiosarcomas and rhabdomyosarcomas. A kinetic study showed that the doubling time (DT) of tumours was closely correlated with the anatomical site of tumour development: bone tumours had a DT of 17.4 +/- 4.3 days and malignant tumours which developed in soft tissues had a DT ranging from 7.4 to 8.4 days with the exception of two haemangiosarcomas which had a long DT of 17 +/- 0.6 days. Pulmonary metastases were frequent for osteosarcomas and tumours of vascular origin. This model of induction of bone and soft-tissue tumours in rats by injection of a colloidal suspension of radioactive cerium chloride offers the possibility of more comprehensive physiopathological and kinetic studies of these tumours and may constitute a good model for their human counterparts.

Animals↗