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Biomedical subjects

B Gosselin

Publications and source records attributed to B Gosselin.

At least 55 records · Page 3Linked to original sources
PubMed1999

Infection with Toxoplasma gondii RH and Prugniaud strains in mice, rats and nude rats: kinetics of infection in blood and tissues related to pathology in acute and chronic infection.

Since mice and rats are the most studied models of experimental toxoplasmosis, the aim of this work was to analyze the outcome of Toxoplasma infection in mice, rats and congenitally athymic nude rats; for this purpose, the parasitic load in different organs and the anatomic-pathological characteristics of infection were investigated in these animals. The data obtained after infection with two different strains and stages of Toxoplasma gondii (RH tachyzoites and Prugniaud cysts) concerned the following organs: brain, mesenteric lymph nodes, blood, spleen, heart, lungs, diaphragm and liver. In Fischer rats, the infection with either the Prugniaud or the RH strains displayed similar characteristics: after a peak in the parasite load, a complete disappearance of parasites was observed, except in the brain of Prugniaud strain-infected rats where toxoplasmas were evidenced throughout the experiment. In OF1 mice, where infection by the RH tachyzoites was lethal, infection with the Prugniaud strain led to survival; the parasitic burden peaked in the different organs and was then undetectable, except in the brain where toxoplasmas were still present during the chronic phase. Like mice, nude rats did not survive to the RH infection. Interestingly, for all the animals the observed histopathological changes in the infected organs, although more or less obvious in the acute phase, were not very severe in almost all cases. For instance, mice, although more susceptible to infection than rats, did not present more severe lesions. They consisted in a discrete inflammation with some focal areas of necrosis in some organs such as brain, liver and heart. Our results support the assumption that rats and nude rats constitute interesting experimental models relevant to either human acute toxoplasmosis, chronic toxoplasmosis, or disseminated toxoplasmosis in AIDS patients.

Acute Disease↗
PubMed1999

[Pneumothorax revealing cystic adenomatoid malformation of the lung in a 13 year old child].

CASE REPORT: A 13 year old boy had a seven day history of chest pain and dyspnea. His right hemithorax was immobile with abolished breathing sounds. Initial chest X-ray revealed a right tension pneumothorax. A chest tube was inserted and the right lung re-expanded. However, despite two intrapleural injections of tetracyclin, the pneumothorax reappeared. Lung CT scan showed an intraparechymal cyst in the posterior part of the right upper lobe. Lobectomy was performed and histological study confirmed the diagnosis of type I cystic adenomatoid malformation of the lung. Two months after surgery, clinical and radiological examinations were normal. CONCLUSION: Spontaneous pneumothorax, as the initial manifestation of cystic adenomatoid malformation of the lung, is rare (three cases reported in children beyond the neonatal period, and two in adults). CT scan features correlate well with the pathologic features. Because of the risk of recurrent pulmonary infections and malignancy change, removal of the cystic lesions is advisable.

Adolescent↗
PubMed1999

Developmental mucin gene expression in the human respiratory tract.

The epithelial surface of the respiratory tract is coated with a protective film of mucus secreted by epithelial goblet and submucosal gland cells. Histology of the airway mucosa and composition of secretions during the second trimester of fetal life are known to differ from the normal adult in that these secretions show similarities with those of hypersecretory disorders. To provide information regarding cell-specific expression of mucin genes and their relation to developmental patterns of epithelial cytodifferentiation, we studied the expression of eight different mucin genes (MUC1-MUC4, MUC5AC, MUC5B, MUC6, MUC7) in human embryonic and fetal respiratory tract using in situ hybridization. These investigations demonstrated that MUC4 is the earliest gene expressed in the foregut at 6.5 wk, followed by MUC1 and MUC2 from 9. 5 wk of gestation in trachea, bronchi, epithelial tubules, and terminal sacs before epithelial cytodifferentiation. In contrast, MUC5AC, MUC5B, and MUC7 are expressed at later gestational ages concomitant with epithelial cytodifferentiation. During this developmental stage, MUC1 and MUC4 mRNAs are located in goblet and ciliated cells, whereas MUC2 mRNAs are located in basal and goblet cells. MUC5AC expression is confined to goblet cells. In the submucosal glands, MUC2 mRNAs are located in both mucous and serous cells, whereas MUC5B and MUC7 mRNAs are expressed in mucous and in serous cells, respectively. These data suggest distinct developmental roles for MUC1, MUC2, MUC4, MUC5AC, MUC5B, and MUC7 in the elongation, branching, and epithelial cytodifferentiation of the respiratory tract during ontogenesis. Distinct patterns of mucin gene expression are also likely to play an important role in regulating appropriate epithelial cell proliferation and cytodifferentiation in adult airway mucosa as it is indicated by aberrant expression in hypersecretory disorders.

Adult↗
PubMed1999

[Biotin-rich pseudoherpetic intranuclear inclusions. A diagnostic pitfall].

Biotin-rich pseudoherpetic nuclear inclusions may be observed in endometrial epithelial cells during pregnancy, post-partum or in association with choriocarcinoma. They may be observed in tumor cells in a few papillary carcinomas of the thyroid gland in young women. These inclusions may be responsible for false diagnoses of herpesvirus infection at morphological and immunocytochemical examination. They may be responsible for false positives in immunocytochemistry and in situ hybridization.

Biotin↗
PubMed1999

[Serous papillary cystadenocarcinoma of the recto-vaginal septum: a rare primary localization].

A primary serous papillary cystadenocarcinoma of the rectovaginal septum was diagnosed in a 35-year-old woman. There were invasive microfoci in peritoneum and lymph node micrometastasis as well as a small superficial non invasive tumor focus in the left ovary. Diagnosis was based on morphological, immunohistochemical and ultrastructural features of tumor tissue. The patient had surgery and post-operative chemotherapy. Progression of peritoneal disease was found six months after surgery. In this very rare location of serous carcinoma, tumor might have developed from peritoneal inclusions in the rectovaginal septum.

Adult↗
PubMed1998

[Lymph node tuberculosis in France in non-immunosuppressed adults: current pathology].

PURPOSE: Lymph node tuberculosis is more frequent in Africa or in HIV-infected patients. METHODS: We review results that were obtained in 18 patients with lymph node tuberculosis but without infection by HIV. Eight French native patients (mean age: 69 years) and ten African patients (mean age: 32.5 years) were included into the study. RESULTS: Of the 18 patients, 14 had exclusively hematopoietic localizations, two with medullar involvement and two with either liver or spleen involvement. Normal erythrocyte sedimentation rate was found in two out of 18 cases and normal C-reactive protein levels in seven out of 17 cases. Lymph node biopsy revealed lesions typically associated with tuberculosis in 12 out of 14 patients, two of them had no necrosis. Inflammatory syndrome was inconstant, tuberculin test sometimes negative. A favorable outcome was seen in all cases after 6, 12 or 18 months of treatment, depending on clinical appreciation. CONCLUSION: Tuberculous lymphadenopathy in non-HIV-infected patients may occur without inflammatory syndrome, with sometimes negative tuberculin test and without lymph node necrosis.

Adult↗
PubMed1998

Intramural injection of biodegradable microspheres as a local drug-delivery system to inhibit neointimal thickening in a rabbit model of balloon angioplasty.

Restenosis remains the major limitation of coronary angioplasty. The objective of this study was to develop microspheres able to be delivered at the angioplasty site for long-term drug release and to test their effects in a model of balloon angioplasty. Polylactic-co-glycolide acid microspheres (5-10 microm in diameter) were prepared by using an oil-in-water emulsion-solvent evaporation method. In vitro experiments with hydrocortisone-loaded microspheres revealed a hydrocortisone release for 4 weeks. We studied the in vivo effect of injection of microspheres into the arterial wall of New Zealand White rabbits by using a perforated balloon. Deep penetration of microspheres in the arterial wall was documented immediately after angioplasty. Intimal hyperplasia was assessed in iliac arteries 4 weeks after angioplasty. The morphometric analysis was performed in four groups of animals; the first group was subjected only to conventional angioplasty (control, n = 10), whereas the other three groups after conventional angioplasty were received perforated balloon angioplasty with saline (n = 10), microspheres (n = 10), or hydrocortisone-loaded microspheres (n = 7). Intramural injection of saline did not induce greater intimal hyperplasia compared with control (0.17 +/- 0.03 vs. 0.18 +/- 0.03 mm2, respectively). Microspheres injection was associated with a trend toward a greater degree of intimal hyperplasia that did not reach statistical significance. Hydrocortisone-loaded microspheres were associated with a significant reduction in intimal hyperplasia compared with unloaded microspheres (0.16 +/- 0.02 vs. 0.26 +/- 0.03 mm2, respectively). The polylactic-co-glycolide acid microspheres are well tolerated, easily injected into the arterial wall, and the increase of intimal hyperplasia is easily inhibited by release of hydrocortisone for 4 weeks after initial injury.

Angioplasty, Balloon↗
PubMed1998

Mucin gene expression in human embryonic and fetal intestine.

BACKGROUND: The intestinal epithelium is covered by a continuous layer of mucus which is secreted by well differentiated epithelial cells. Disregulation of the expression of mucins has been reported to have possible implications in the neoplastic process which affects intestinal mucosae. It is well known that preneoplastic and neoplastic tissues can express fetal phenotypic characteristics. AIMS: To assess whether the expression of mucin genes in the intestinal tract is linked to the stage of cellular differentiation and tissue development, by studying the expression of six mucin genes in human fetal small intestine and colon, and also adult tissues. METHODS: In situ hybridisation was used to study mRNA expression of MUC2, MUC3, MUC4, MUC5B, MUC5AC, and MUC6 in 32 human embryos and fetuses (6.5-27 weeks gestation). Normal adult mucosae were used as controls. RESULTS: Three mucin genes, MUC2, MUC4, and MUC5AC, were differently expressed in fetal intestine compared with expression in normal adults. CONCLUSION: These differences in mucin gene expression suggest a possible regulatory role for these products in intestinal epithelial cell differentiation.

Adult↗
PubMed1998

[Ovarian mucinous tumor of gastric and intestinal type associated with Peutz-Jeghers syndrome: in situ hybridization study of apomucin gene transcripts].

Occurrence of mucinous tumors is favored by Peutz-Jeghers syndrome (PJS). A case of bilateral ovarian mucinous tumor associated with ovarian mature teratoma occurring in a 22-year-old woman with PJS was reported. Tumor cells included 5 cell types: tall columnar mucinous pale cells with neutral mucins; goblet cells with acidic nonsulfated mucins; non mucinous columnar cells; mucinous cuboidal cells lining small glands; endocrine cells. Expression of the MUC2, MUC3, MUC5AC and MUC6 genes was demonstrated by in situ hybridization according to cell type. Some atypia and numerous mitotic figures were observed in basal glands. Diagnosis was ovarian borderline mucinous tumor with gastric and intestinal phenotype associated with PJS.

Adenocarcinoma, Mucinous↗
PubMed1998

[Importance of the study of the expression of MIB-1 (Ki-67) for the diagnosis of endocervical glandular lesions].

The morphological criteria for the diagnosis of endocervical atypia and dysplasia are variably defined. Diagnosis is difficult. MIB-1 (Ki-67) cell proliferation-associated antigen was detected retrospectively by immunohistochemistry in 230 cervical cone specimens. The percentage of MIB-1 positive cells was 1 to 25% (median 2%) and limited to small hot spots in normal and subnormal glands (140 cases). It was 1 to 30% (median 4%) in endometrioid metaplasia and microglandular hyperplasia (55 cases); 30 to 60 (median 40%) and limited to 1-3 glands in atypia (24 cases); 45 to 60% (median 50%) and diffusely distributed in dysplasia (5 cases). In situ (3 cases) and invasive (3 cases) adenocarcinomas were characterized by a high% (> 60) of MIB-1 positive cells.

Adenocarcinoma↗
PubMed1997

Effects of N omega-nitro-L-arginine methyl ester on the endotoxin-induced disseminated intravascular coagulation in porcine septic shock.

OBJECTIVES: Nitric oxide is known to prevent platelet aggregation and clot formation. Inhibitors of nitric oxide synthase might promote or enhance endotoxin disseminated intravascular coagulation. The present study was designed to evaluate the effects of the arginine analog, N omega-nitro-L-arginine methyl ester (L-NAME), on the endotoxin-induced disseminated intravascular coagulation in a porcine model of septic shock. DESIGN: Prospective, comparative, experimental study. SETTING: Laboratory at a large university hospital. SUBJECTS: Sixteen female piglets, weighing 20 to 28 kg. INTERVENTIONS: Three groups of animals were studied: a control group (n = 6); a lipopolysaccharide (LPS)-treated group (n = 5) receiving Escherichia coli endotoxin (5 micrograms/kg/min over 30 mins); and an LPS + L-NAME group (n = 5) receiving endotoxin and, 1 hr after, a bolus of L-NAME (25 mg/kg). MEASUREMENTS AND MAIN RESULTS: Hemodynamic changes, usual coagulation parameters, and plasma concentrations of thrombin-antithrombin complexes, antithrombin III activity (At III), tissue plasminogen activator, plasminogen activator inhibitor type 1, and von Willebrand factor were measured at baseline, and at 30, 60, 90, 120, 180, 240, and 300 mins. After euthanasia or death, lungs and kidneys were withdrawn for histologic study. The extent of microvascular thrombosis was assessed by a semiquantitative disseminated intravascular coagulation score. In both septic endotoxin group, administration of LPS resulted in hemodynamic changes typical of severe septic shock, with disseminated intravascular coagulation and histologic changes characterized by adult respiratory distress syndrome and kidney microthrombosis. L-NAME administration normalized mean arterial pressure with a dramatic increase in systemic vascular resistances and a marked decrease in cardiac index. The changes in usual coagulation parameters, AT III, tissue plasminogen activator, and plasminogen-activator inhibitor type 1 concentrations were not different between both septic groups. However, in the LPS + L-NAME group, thrombin-antithrombin complexes and von Willebrand factor were higher and associated with a higher histologic disseminated intravascular coagulation score. CONCLUSION: In this model of endotoxin septic shock, L-NAME administration resulted in histologic and coagulation changes consistent with an increased activation of intravascular coagulation.

Animals↗
PubMed1997

Bronchial arteries in the pig before and after permanent pulmonary artery occlusion.

RATIONALE AND OBJECTIVES: The authors study the bronchial arteries in the adult pig before and after pulmonary artery occlusion. METHODS: The bronchial artery anatomy was analyzed on postmortem aortograms in six pigs in group 1. In 20 animals in group 2, the left diaphragmatic lobar pulmonary artery (DLPA) was proximally (n = 12), medially (n = 5), or distally (n = 3) occluded via angiographic procedures; an unintentional embolization of coils in the right DLPA led to an incomplete pulmonary arterial occlusion. Eight to 12 weeks later, postmortem bronchial angiograms and pathologic studies were performed systematically in group 2. RESULTS: Outcomes in group 1 were: (A) a common trunk to the right and left bronchial arteries found in five animals, and (B) bronchopulmonary anastomoses found in the five lungs optimally injected. Outcomes in group 2 were: (A) the absence of pulmonary infarct and the development of a collateral bronchial supply were constant in the left lung; (B) the left DLPAs were patent beyond the coils and opacified via bronchopulmonary anastomoses; (C) dilated subpleural bronchial arteries were constant in the interlobular septa of the lung parenchyma devoid of pulmonary arterial perfusion; (D) the right bronchial arteries were normal after incomplete pulmonary artery occlusion. CONCLUSIONS: Because of an anastomosed dual circulation, the pig is a reliable experimental model for interventional and surgical procedures.

Animals↗
PubMed1997

MCP-1 secretion in lung from nonsmoking patients with coal worker's pneumoconiosis.

Exposure to coal dust leads to the development of coal worker's pneumoconiosis (CWP), a disease associated with an accumulation of macrophages in the lower respiratory tract. Mechanisms controlling monocyte recruitment are still poorly understood. Since monocyte chemoattractant protein-1 (MCP-1) is recognized as a potent chemotactic factor for blood monocytes, we analysed the presence of MCP-1 in the pulmonary compartment of patients with CWP. Bronchoalveolar lavage fluid (BALF) from 16 nonsmoking control subjects and 27 nonsmoking CWP patients (16 with simple pneumoconiosis (SP) and 11 with progressive massive fibrosis (PMF)) was analysed. Alveolar macrophages (AMs) were purified by adherence and BALF was concentrated tenfold by lyophilization. MCP-1 was measured in BALF and in 3 h AM supernatants using a sandwich enzyme-linked immunosorbent assay (ELISA). The localization of MCP-1 in lung tissue was determined by immunohistochemistry on tissue sections from three patients with CWP and two control subjects. MCP-1 levels were significantly higher in concentrated BALF from patients with SP or PMF (median 370 and 555 pg x mL-1, respectively) than in those from control subjects (median 11 pg x mL-1) (p<0.001). Released MCP-1 in AM supernatants was enhanced in patients with CWP (median 83 pg x mL-1) but compared to controls (median 41 pg x mL-1) this level did not reach significance. Although significantly increased, AM counts in BALF from patients with CWP did not correlate with MCP-1 levels. MCP-1 levels in BALF correlated with MCP-1 levels in AM supernatants (p=0.47; p<0.02). In control lung specimens, MCP-1 was expressed by a few AMs, type II pneumocytes and perivascular smooth muscle cells. CWP sections were characterized by an increased number of AMs and mainly by the presence of fibroblasts (in the myogenic area of fibrotic lesions) and hyperplastic type II pneumocytes, which were strongly immunostained for MCP-1. Our data demonstrate that: 1) patients with coal worker's pneumoconiosis have a marked pulmonary overproduction of monocyte chemoattractant protein-1; and 2) in addition to alveolar macrophages, fibroblasts (probably myofibroblasts) and hyperplastic type II pneumocytes may also be responsible for this increased level of monocyte chemoattractant protein-1 in coal worker's pneumoconiosis.

Aged↗