PubMed Health⌕ Search

Biomedical subjects

F Coignoul

Publications and source records attributed to F Coignoul.

32 records · Page 2Linked to original sources
PubMed1996

A morphometric and functional study of the toxicity of atmospheric ammonia in the extrathoracic airways in pigs.

The effects of atmospheric ammonia (NH3) on the nasal and tracheal mucosa of pigs were investigated by morphometric and functional methods. Pigs were exposed to four concentrations of NH3 [5 (control), 25, 50 and 100 ppm] for 6 days in a specially designed air-pollutant exposure chamber. Samples were taken from the turbinates and the trachea, and the respiratory mucosa was examined by light and scanning electron microscopy. Dose-response curves to carbachol and isoproterenol were constructed using isolated strips of tracheal smooth muscle, with or without epithelium. In pigs exposed to ammonia, considerable mucosal injuries were observed in the turbinates but not in the trachea. The number of neutrophils in the epithelial layer and in the lamina propria, and epithelial hyperplasia were closely and significantly correlated with the concentrations of ammonia (r = 0.894, p < 0.001; r = 0.727, P < 0.001; and r = 0.818, p < 0.001, respectively). Except for the lamina propria, all these changes were significant (p < 0.05) at ammonia concentrations as low as 25 ppm. The percentage of the surface of the turbinate mucosa that was ciliated tended to decrease with increasing ammonia concentration (r = 0.439, p < 0.082). Ammonia induced smooth-muscle hyperresponsiveness to carbachol with a close linear correlation between individual values of the carbachol-induced maximal effect and the NH3 concentrations (r = 0.526, p < 0.003). While mechanical destruction of the epithelium induced an increase in Emax in the control group, no difference was observed between the intact and denuded strips from animals exposed to ammonia. The response to isoproterenol was not influenced by ammonia. It was concluded that quantitative histological analysis of the inflammatory infiltration and epithelial hyperplasia in the turbinates is a useful tool for quantifying the effects of atmospheric pollutants in pigs; a 6-day exposure to ammonia induces nasal irritation and functional disturbances of the tracheal smooth-muscle contractions at concentrations as low as 25 ppm.

Adrenergic beta-Agonists↗
PubMed1996

Imprint and brush cytology in the diagnosis of canine intranasal tumours.

Fifty-four dogs with nasal tumours were included in this study. Based on histopathology 52 tumours were malignant (36 epithelial and 16 mesenchymal) and two were benign (one oncocytoma and one pleiomorphic adenoma). Malignancy was significantly more frequently diagnosed by imprint cytology (81 per cent of the cases) than by brush cytology (56 per cent). Brush cytology was a significantly more sensitive technique in epithelial than in mesenchymal tumours, while the sensitivity of imprint cytology was not affected by the histological type. Brush cytology determined an epithelial origin in 88 per cent of epithelial tumours, and imprint cytology in 90 per cent. In mesenchymal tumours, the scores were significantly lower, the histological type being determined in only 20 per cent and 50 per cent, using brush and imprint cytology, respectively.

Adenocarcinoma↗
PubMed1995

Image analysis evaluation of ploidy, S-phase fraction and nuclear area in canine mammary tumours.

Image analysis was used on cytocentrifuge preparations of Feulgen-stained nuclei extracted from formalin-fixed, paraffin wax-embedded tissues to determine ploidy (assessed by integrated optical density), S-phase fraction, and nuclear area of 90 canine mammary tumours (30 benign and 60 malignant). Only two lesions identified histologically as benign were aneuploid, suggesting potential malignancy. Of malignant tumours, 37% were aneuploid. No distinction based on ploidy could be made within benign or malignant groups, except for tubular adenocarcinomas of complex type, all of which were diploid. Mean S-phase fraction of malignant lesions (15.60%) was twice that of benign lesions (7.87%; P < 0.0001). The mean nuclear surface was significantly smaller in malignant lesions (70.62 microns2) than in benign counterparts (77.45 microns2; P < 0.05). No relation was found between a given tumour type and S-phase fraction or nuclear area within histologically malignant or benign tumour groups. Infiltration of lymphatics by neoplastic cells, known to indicate a poor prognosis, was associated with aneuploid lesions (mean DNA index > 1.25) and high S-phase fraction. The presence of necrosis and of a high number of mitoses was significantly associated with high S-phase fraction lesions.

Animals↗
PubMed1995

Comparison of argyrophilic nucleolar organizer regions by counting and image analysis in canine mammary tumors.

Two techniques for evaluating argyrophilic nucleolar organizer regions (AgNOR) were compared on 74 canine mammary tumors to discriminate between benign and malignant lesions. For each lesion, direct counting of AgNOR on at least 100 cell nuclei was compared with area, perimeter, and integrated optical density AgNOR dot values determined by image analysis. Significant differences between benign and malignant tumors were observed with both methods; however, lesions determined as aggressive or proliferative by histologic evaluation were only singled out by image analysis measurements. Image analysis, in our hands, was a reliable, precise, and convenient technique to characterize malignancy in canine mammary tumors.

Animals↗
PubMed1993

Immunohistochemical identification of myoepithelial, epithelial, and connective tissue cells in canine mammary tumors.

Fifty-eight formalin-fixed paraffin-embedded canine mammary tumors, 19 malignant and 39 benign, were used in this study. Tumors were obtained from dogs submitted for surgical resection of lesions at private veterinary practices in Brussels or from the surgery unit of the Faculty of Veterinary Medicine, University of Liège. Immunohistochemical evaluation was performed, using monoclonal antibodies directed against keratins 8-18 and 19, vimentin, desmin, and alpha-actin and polyclonal antibodies directed against high-molecular-weight keratins and S-100 protein. The main cell types, epithelial, myoepithelial, and connective, were identified, and myoepithelial cells represented the major component of most tumors, both benign and malignant. Myoepithelial cells had five patterns: resting and proliferative suprabasal cells, spindle and star-shaped interstitial cells, and cartilage. Reactivity to keratin 19, vimentin, alpha-actin, and S-100 protein suggested a progressive transformation from resting cells to cartilage. Epithelial cell reactivities were limited to keratins; only keratinized cells were positive for polyclonal keratins. Myofibroblasts were positive for both vimentin and alpha-actin, and connective tissue cells were positive for vimentin. Myoepithelial cells appeared to be the major component of carcinomas, justifying reevaluation and simplification of histomorphologic classifications, with a "pleomorphic carcinoma" group including all carcinomas except squamous, mucinous, and comedo carcinomas. Immunohistochemical evaluation, in addition to routine hematoxylin and eosin histopathologic evaluation is recommended for precise classification of canine mammary tumors.

Actins↗
PubMed1990

[Alveolar macrophages of sheep: purification and identification].

Broncho-alveolar lavages of sheep lungs were performed for alveolar macrophage identification and purification. The total number of harvested cells was 1.5 x 10(8) cells per 600 ml fluid lavage, with a mean of 2.48 x 10(5) cells/ml. Cell viability was 97.14%. Alveolar macrophages represented 78% of cells harvested. Separation was carried out by adherence to plastic flasks followed by Percoll centrifugation. The best results (purity of macrophage population and cell viability) was obtained with Percoll solution and NaCl 1.5 mol.l-1 with a density of 1.033 and 1.050. Identification was carried out by the non specific esterase staining method. In conclusion, broncho-alveolar lavage of isolated sheep lung is a simple and reliable method of respiratory tract cell collection.

Animals↗
PubMed1989

Experimental infection of bulls with a genital isolate of bovine herpesvirus-4 and reactivation of latent virus with dexamethasone.

Five 13- to 18-month old Belgian Blue bulls were used in this experiment. Four bulls (Nos. 2, 3, 4 and 5) were inoculated intratesticularly with 10(5) plaque-forming units of bovine herpesvirus-4 (BHV-4) in each testicle (Day 0). The challenge BHV-4 strain was previously isolated from testicle cells of a bull exhibiting orchitis and azoospermia. The fifth bull (No. 1) was used as a control and received the same volume of uninfected cell culture supernatant. For 5 days, beginning on Day 51 post-infection, two bulls (Nos. 4 and 5) and the control bull (No. 1) received 0.1 mg kg-1 of dexamethasone. Unilateral castrations were then performed at regular intervals for viral examination. Treatment with dexamethasone reactivated latent BHV-4, but no clinical signs were observed in treated bulls until the end of the experiment (Day 93). Only Bull 3 showed conjunctivitis and temporary azoospermia. The virus was recovered from various samples showing that: (i) BHV-4 can be present in a latent state in the testicles and mononuclear blood cells; (ii) dexamethasone reactivates the virus; (iii) the virus is excreted by nasal and ocular routes. Each infected bull seroconverted and a booster antibody response appeared after dexamethasone treatment as shown by immunofluorescence. Neutralizing antibodies were detected in each bull by complement-dependent neutralization test with titres higher than those obtained by a classical neutralization test. No booster response of neutralizing antibodies was observed after dexamethasone treatment. The antigenically relevant envelope BHV-4 proteins were identified by Western blotting using sera samples from the animals. DNA restriction endonuclease profiles of viruses reisolated after primary infection and reactivation showed only small differences.

Animals↗
PubMed1989

Eurytrema coelomaticum infection in bovines in an abattoir in south Brazil.

Two and a half per cent of the 200 bovines examined in an abattoir in South Brazil had pancreatic gross lesions associated with Eurytrema coelomaticum infection. The lesions were mainly subacute periductular pancreatitis and the accompanying alterations in the adjacent parenchyma. Relevant literature is reviewed and compared with the results of the present study.

Animals↗
PubMed1984

Calcium in the turkey yolk sac during late development and postembryonic involution.

Yolk sacs (YS) were examined by gross, histochemical, and electron microscopic techniques from incubation day 12 to 10 days of age. Weights were maximal at 22 days of incubation and declined markedly thereafter; by 7 days of age, the yolk was completely absorbed. Endodermal cells of YS epithelium were highly polar with nuclei, mitochondria, and glycogen in basal areas and lipid globules and intralysosomal yolk granules near luminal surfaces. Yolk laminar spherules were first seen at day 16 of incubation. They increased progressively with incubation and disappeared rapidly after hatching. Spherules stained for calcium, glycosaminoglycans, and alkaline phosphatase in late incubation and were considered calcium storage structures. Histochemical evidence of intracellular calcium loading of yolk matrix (from 18 days of incubation until 5 days of age) suggested a specific calcium transport function of YS epithelium.

Aging↗
PubMed1979

Canine hemorrhagic enteritis: detection of viral particles by electron microscopy.

At necropsy, several dogs which died showing symptoms of hemorrhagic diarrhea, had significant lesions of the mucosa that were found especially in the duodenum and upper part of the small bowel. Study of ultrathin sections from the diseased mucosa revealed particles resembling parvoviruses in altered nuclei of cells of the intestinal crypts. Electron microscopic examination of intestinal contents by negative staining has shown the presence of many viral particles which have a diameter of 24 nm and whose profile is consistent with an icosahedral shape. These virions float at a density of 1.43 g/cm3 in cesium chloride and agglutinate rhesus monkey and swine red blood cells at 4 degrees C. A possible etiological role is discussed. This virus is compared with the minute virus of canines and the Feline Panleukopenia virus.

Animals↗
PubMedDate not supplied

Enzyme-histochemical detection of a chymase-like proteinase within bovine mucosal and connective tissue mast cells.

The presence of chymase-like proteinase in bovine mast cells was investigated by an enzyme-histochemical technique (naphthol-AS-D-chloroacetate as substrate) in normal skin, primary bronchus, lung and duodenum. The counts and distribution of chymase-positive and toluidine blue-positive mast cells were compared by means of successive staining. Mast cells with chymase-like activity were detected in all areas, but their proportion was greater in connective than mucosal tissues, with the exception of the skin. These results contrast with those obtained in rodents, in which chymase-like proteinases are detected in all tissues and also in all mast cells. Bovine mast cells are closer to those of human beings, in which chymase-containing mast cells predominate in connective tissues, including skin. The results suggest that more than one chymase subset is present, at least in duodenum. The possible occurrence of dual-specific chymase mast cells, as in other ruminants, is discussed.

Animals↗
PubMedDate not supplied

Pathological findings in two fin whales (Balaenoptera physalus) with evidence of morbillivirus infection.

Two immature female fin whales stranded on the Belgian and French coastlines, were examined post mortem. The main gross findings were massive parasitic infestation, associated with a large thrombus in one whale, and severe emaciation. Microscopical investigations revealed multinucleated syncytia with large intranuclear inclusion bodies in various tissues, and positive immunolabelling for morbillivirus antigens. Other evidence of morbillivirus infection was provided by the demonstration of specific viral structures in syncytia and in cell cultures, and the detection of neutralizing antibodies to canine distemper virus. To the authors>> knowledge, this is the first firm report of morbillivirus infection in baleen whales.

Animals↗
PubMedDate not supplied

Bronchopulmonary and disseminated granulomatous disease associated with Aspergillus fumigatus and Candida species infection in a golden retriever.

A seven-year-old, female golden retriever was referred for a paroxysmal, chronic cough and dyspnea, dysphagia, facial pruritus, anterior uveitis, and deteriorating general condition. A severe, mixed interstitial and alveolar pattern, with poorly defined amorphous lesions, was seen on thoracic radiographs. Multiple, whitish nodules disseminated on the hyperemic respiratory mucosa were noted on bronchoscopy. Escherichia coli and Aspergillus fumigatus were cultured from the bronchoalveolar lavage. Granulomatous lesions in numerous organs were identified during necropsy, and Aspergillus fumigatus and Candida spp. were cultured from lung and kidney tissues. Microscopic granulomatous lesions were compatible with mycotic infection; however fungal organisms were not observed.

Animals↗