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Biomedical subjects

R Masse

Publications and source records attributed to R Masse.

At least 91 records · Page 5Linked to original sources
PubMed1983

Acute effects of intratracheal administration of platelet-activating factor in baboons.

The bronchomotor effect of intratracheal administration of PAF-acether (60 micrograms X kg -1) was investigated in 37 curarized baboons mechanically ventilated with constant volume and frequency. PAF-acether caused an immediate bronchoconstriction as assessed by a marked increase in peak inspiratory pressure with no change in static pulmonary compliance and chest X-rays. There was a concomitant fall in arterial PO2 and a significant increase in ventilated unperfused lung zones. A decrease of circulating platelets and leucocytes was also observed. Local anesthesia with lidocaine and atropine did not prevent PAF-acether-induced bronchoconstriction although both markedly reduced the bronchial response to histamine. Albuterol significantly reduced the bronchial response to PAF-acether. Pretreatment with aspirin (80 mg X kg -1 iv) did not prevent the bronchoconstriction caused by PAF-acether, and intravenous or intratracheal arachidonic acid caused no bronchial response. Thus the role of cyclooxygenase metabolites of arachidonic acid in PAF-acether-induced bronchoconstriction is unlikely. In conclusion, an acute bronchoconstriction probably not triggered by stimulation of irritant receptors of the airways and associated with aggregation of platelet takes place subsequent to intratracheal administration of PAF-acether. These data suggest that PAF-acether might play a role in the pathogenesis of human asthma.

Anesthesia, Local↗
PubMed1982

[Accidental localized vaccinia. A report of six recent cases (author's transl)].

Vaccination against smallpox should be discontinued in all countries except for individuals with a high risk of exposure (WHO, 1980). Since this vaccination is performed less and less often, one must expect complications to occur, the etiology of which may not be recognized. This course of events leads the authors to point out the difficulties in diagnosis and therapy of localized accidental vaccinia encountered in six patients hospitalized in Brest (1971-1979). Diagnosis is considered if the patient himself, or a person he came in contact with, was recently vaccinated. Diagnosis should always be established by virology. Such accidents can be avoided by a faultless vaccination technique and by giving sufficient information to the inoculated subject or to his relatives.

Adolescent↗
PubMed1982

Increased content of neutrosoluble collagen and dialyzable hydroxyproline in panacinar emphysema and spontaneous pneumothorax.

Hydroxyproline transfer to an incubation medium was studied in ten emphysematous, nine relapsing pneumothorax, and eight control samples surgically removed from 2 females and 25 males, ranging in age from 17 to 69 years. Total hydroxyproline in the lung pieces, expressed as a fraction of DNA, was not modified. A large increase of dialyzable and nondialyzable hydroxyproline fraction was observed in the incubation medium of biopsies from emphysema dn pneumothorax groups. Although the pneumothorax group had average values between controls and emphysema, some pneumothorax patients exhibited very high content of soluble hydroxyproline, suggesting a common pattern between some relapsing pneumothorax and emphysema. These findings could not be due to extracellular degradation during the processing of the samples since the results were not affected by the presence of protease inhibitors. These observations suggest that individuals with emphysema and pneumothrax have abnormalities in lung collagen structure and/or biosynthesis resulting in increased degradation of this macromolecule.

Adolescent↗
PubMed1982

[Measurement of leukocyte accumulation in the capillaries in the lesser circulation of the rat: extraction of cells and characterization of enrichment in monocytes].

We have performed a qualitative and quantitative study of leucocytes in lung alveolar capillaries. This population is not an artefact induced by experimental procedure because the same population is observed after instant cardiac arrest. About 30% of these leucocytes can be extracted by perfusion, the extracted population being representative of the whole one present in capillaries. The experimental procedure used allow to collect 100.10(6) leucocytes per animal 15.10(6) of which are monocytes easily obtained as a purified population. From these results lung capillaries contain at least as many leucocytes as the whole circulating blood and 5 times more monocytes.

Animals↗
PubMed1981

Bronchoconstriction induced by intratracheal administration of platelet-activating factor (PAF-acether) in baboons.

Intratracheal administration of PAF-acether (60 microgram.kg-1) was performed in six premedicated, curarized and mechanically ventilated baboons. Whereas intratracheal administration of an equal amount of solvent (200 microliter of 80 degrees alcohol in 2 ml of saline) caused no measurable changes in lung mechanics, administration of PAF-acether caused an almost immediate bronchoconstriction that was spontaneously reversible within about 30 min. The concomitant fall in platelet count in peripheral blood and reduction of perfusion of ventilated lung territories estimated from the alveolar-arterial difference in CO2 tension provide circumstantial evidence that PAF-acether also caused aggregation of platelets in the lung microcirculation. In keeping with the release of PAF-acether by human alveolar macrophages, our findings suggest that this mediator may play a role in human asthma.

Airway Resistance↗
PubMed1981

Mesotheliomas in rats following inoculation with acid-leached chrysotile asbestos and other mineral fibres.

The carcinogenicity of untreated UICC chrysotile A, of acid (oxalic and hydrochloric)-leached UICC chrysotile A, of crocidolite and of JM 104 glass fibres has been studied by intrapleural injection into rats. This experiment, carried out on 304 animals, demonstrated that when more than 80% of the Mg had been leached from chrysotile fibres by either hydrochloric or oxalic acid, the proportion of pleural mesotheliomas was either nil or dramatically lower than that obtained with untreated chrysotile. The carcinogenic effect of crocidolite was higher than that of 43.7% oxalic acid-leached chrysotile. The proportion of mesotheliomas observed in animals injected with JM 104 glass fibres was similar to that in animals injected with fibres from which 63.8% had been leached with oxalic acid. These results indicate that with regard to the induction of pleural carcinogenicity by chrysotile fibres, not only size characteristics but also parameters such as chemical composition and physiochemical properties must intervene.

Animals↗
PubMed1981

[Renewal of bronchial and pulmonary cells: a comprehensive review of recent information (author's transl)].

In the bronchi, the ultrastructural findings allow a schema to be established of proliferation-differentiation of basal cells, undifferentiated cells and mucus cells. In the bronchioles, the Clara cells or an immediate progenitor seem at the same time to play the role of stem cell for ciliated cells, mucus cells and brush cells. Same observations suggest that the bronchial and bronchiolar stem cells may produce neuro-secretary cells; the increase in neuro-secretary cells is a common enough phenomenon under the influence of numerous stimuli. No evidence of neuro-secretory cells dividing was observed. The histology and the kinetics of the cell population of bronchus associated lymphoid tissue (BALT) are reviewed. In the parenchyma, the role of the pneumocyte in restoring epithelial cells to high concentrations of oxygen is also discussed. Throughout the literature and also in the authors' experience, attention is drawn to the lack of correlation between the inflammation cell septal infiltrate and the endo-alveolar population. The cytokinetics of the alveolar macrophages (MA) are reviewed and recent findings discussed, including the absence of maintained cell division of the MA, the recruitment of young cells, the heterogenous distribution in the tissues of actively mitotic macrophages and the role of chemotactic factors.

Aluminum↗
PubMed1981

[Two cases of skin pigmentation in association with minocycline therapy (author's transl)].

Report of two cases of skin pigmentation during minocycline therapy. Examination showed confluent blue-gray oval patches on the anterior part of the legs, occurring after ingestion of respectively 12 g and 100 g of minocycline. Microscopic examination of each case was identical and showed two lesions: increase in the amount of melanine deposition in the basal layer of the epidermis; presence of brown-black pigment at all the level of the dermis but specially near the sweet glands. This pigment was strongly positive with Perls' stain. Electron microscopic examination showed a finely granular pigment exclusively intracellular in dermis fibroblast and macrophage. This pigment seemed to contain mainly hemodiderine.

Hemosiderin↗
PubMed1981

Characterization of a major natural killer activity in rat lungs.

A high level of antitumoral cytotoxicity was observed in the lymphoid population extracted by perfusion from lung capillaries. The in vitro cytotoxicity against tumor cells was demonstrated with the murine lymphoma YAC-1 cells or with the syngeneic P 77 rat lung fibrohistiocytoma cells. It was demonstrated that this cytotoxic activity had the characteristics of natural killer activity. At the same effector to target ratio the efficiency of this population was higher than in blood or spleen. Since the total number of lymphoid cells arrested in the capillary of the lungs is very high the lungs seemed an immunologically privileged site. A close relationship was observed between this activity in vitro and the rapid elimination in vivo of same tumor cells trapped in lungs (more than 99% after 24 hours).

Animals↗
PubMed1980

Malignant bone tumours induced by a local injection of colloidal radioactive 144Cerium in rats as a model for human osteosarcomas.

Lung metastases were observed in 80% to 85% of rats bearing advanced malignant bone tumours (osteogenic osteosarcomas and angiosarcomas). These tumours were induced in 2-month-old Sprague-Dawley rats by inoculation of a colloidal suspension of radioactive cerium (144Ce) into the hind leg, in close contact to the bones of the knee joint. Twenty-eight rats were killed or died spontaneously shortly after detection of palpable tumours at the site of injection: the incidence of lung metastases was 73.3% and 53.8%, respectively, for osteogenic sarcomas and angiosarcomas, showing that most lung metastases are present at the time of diagnosis of the primary tumour. Tumour-cell kinetic parameters were studied in 49 rats bearing tumours following intraperitoneal injection of [3H]thymidine. The labelling index (LI) of the primary tumours was significantly lower in advanced tumours (7.2% for osteosarcomas and 10.1% for angiosarcomas) than than in tumors examined at the time of detection (12.2% and 13.5%, respectively). Mitotic indices (MI) of all tumours were less than 1%. From the curve of the percentage of labelled mitoses (PLM) at different times after [3H]thymidine injection, Ts (6.5 h) and TG2 (1.75 h) were determined. TC and TG1 were also evaluated (18 h and 9.25 h, respectively). These results show that malignant bone tumours induced in rats with 144Ce may be a good model for human osteosarcomas and may be useful in studying the numerous problems in the therapy of malignant bone tumours in man.

Animals↗
PubMed1980

Bone tumours induced in rats with radioactive cerium.

A technique is described for the induction of metastasizing bone tumours in rats by local inoculation of 144cerium. Bone sarcomas develop in 90% of the animals and 74% of these had lung metastases. The tumours can be easily cultured and maintained by serial transplantations. Preliminary data of clinical, histological and kinetic characteristics of these bone tumours are given.

Animals↗