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F Plenat

Publications and source records attributed to F Plenat.

At least 37 records · Page 2Linked to original sources
PubMed1992

Mechanism for the recruitment of macrophages to cancer site. In vivo concentration gradient of monocyte chemotactic activity.

BACKGROUND: Tumor stroma is characterized by the development of new blood vessels, an inflammatory cell infiltration, and a fibrotic reaction. The inflammatory component of tumor stroma plays an important role in the modulation of tumor expansion. In this respect, macrophages constitute a major part of the inflammatory cell infiltration and can exert cytotoxic activity against tumor cells. The accumulation of macrophages in the vicinity of the tumor suggests their recruitment from circulating blood monocytes through the local release of chemotactic factors for monocytes. METHODS: To detect the existence of a concentration gradient of monocyte chemotactic activity (MCA) between the tumor vicinity and blood vessels, malignant pleural effusions defined by the local presence of cancer cells were evaluated for quantification of MCA. RESULTS: Unlike nonmalignant pleural effusions, malignant pleural effusions were characterized by the presence of increased levels of MCA, and in lung adenocarcinoma (a cancer with high inflammatory cell infiltration), pleural levels of MCA were significantly greater than in small cell lung carcinoma (a cancer with low inflammatory cell reaction). An MCA concentration gradient between pleural fluid and plasma was present in malignant effusions because pleural MCA levels in all cancer types were significantly greater than MCA levels in the plasma of the same patients. CONCLUSIONS: Thus, an increased local level of MCA is a feature of cancers with high inflammatory cell infiltration, and the presence of an in vivo concentration gradient of MCA suggests the direct role of this biologic activity in recruiting blood monocytes to the cancer site.

Adenocarcinoma↗
PubMed1992

Host-donor interactions in healing of human split-thickness skin grafts onto nude mice: in situ hybridization, immunohistochemical, and histochemical studies.

The behavior of host and donor cell lines in human split-thickness skin grafts onto nude mice was studied by in situ hybridization (ISH) using genomic DNAs as probes, and immunohistochemically with species-specific or cross-species specific antibodies, at different stages ranging from day 3 to more than 1 year following grafting. Changes in the graft vascular and interstitial extracellular matrix were also assessed using species-specific or cross-species specific antibodies to human or murine type I, III, and IV collagens. Finally, transplant reinnervation was investigated using antibodies to various nerve cytoplasmic antigens and the thiocholine method to demonstrate acetylcholinesterase. Using these methods we were able to show the following: (1) the graft epidermis that is not replaced by mouse keratinocytes is progressively colonized by recipient Langerhans cells (LCs); (2) revascularization of the grafts begins soon by inoculation of the graft vessels with the host microcirculatory bed, and mouse endothelial cells growing into preexisting human capillary tubes produce a new basement membrane, prior to the replacement of the original one; (3) within 3-5 days following grafting, mouse fibroblasts migrate into the graft dermis. The density of the human and murine fibroblast populations then progressively increases. Characterization of the interstitial collagens identifies both human and murine type I and III collagens. Production of type III collagens decreases during the progression of fibrogenesis while human type I collagen becomes the predominant matrix protein; (4) transplant reinnervation is deficient, and neurites growing into severed graft nerve trunks were never detected.

Animals↗
PubMed1992

Parenteral administration of trypsin triggers lung emphysema.

Eight weeks after a single intravenous injection of trypsin, more than half of 26 treated rats showed pulmonary emphysema, as demonstrated by a significant increase of the mean linear intercept (MLI = 107 microns) in comparison with 11 controls (69 +/- 15 microns) (mean +/- SD). As observed 56 days after the injection, the intraperitoneal administration of trypsin (24 rats) also leads to lung emphysema (MLI = 101-106 microns), as does endotracheal instillation of elastase (13 rats), (MLI = 108 microns). The intraperitoneal administration of trypsin in animals constitutes a model close to human pathology with which lung alterations in acute pancreatitis may be studied. Having no elastolytic properties, trypsin cannot directly induce emphysema. The observation of a pulmonary leucostasis in eight rats sacrificed early after the trypsin injection suggested that leucocyte trapping and activation are important for the genesis of this trypsin-triggered emphysema.

Acute Disease↗
PubMed1991

Presence of platelet-derived growth factor in normal and fibrotic lung is specifically associated with interstitial macrophages, while both interstitial macrophages and alveolar epithelial cells express the c-sis proto-oncogene.

Normal lung structure is maintained by the presence of mesenchymal cells and their extracellular matrix products. The slow normal turnover of these cells is disrupted in fibrotic disorders, resulting in the in situ accumulation of mesenchymal cells and their extracellular matrix leading to a progressive alveolar wall thickening. Idiopathic pulmonary fibrosis (IPF) is a chronic fibrotic disorder of the lung characterized by a diffuse interstitial and intra-alveolar inflammation dominated by macrophages and polymorphonuclear neutrophils. Evaluation of alveolar macrophages (AM) obtained by bronchoalveolar lavage has previously shown that AM from normal individuals spontaneously release small amounts of platelet-derived growth factor (PDGF), a chemotactic and growth factor for mesenchymal cells, whereas AM from IPF patients spontaneously release increased amounts of biologically active PDGF, suggesting its involvement in mesenchymal cell accumulation. However, other cells such as endothelial cells and vascular smooth muscle cells can also release PDGF in vitro. In order to specify PDGF location in lung parenchyma, open lung biopsies from normal individuals and IPF patients were examined by immunohistochemistry using an anti-PDGF antibody and by in situ hybridization using PDGF A-chain and B-chain gene probes. In normal as well as in fibrotic lung, PDGF was only present in relation with interstitial macrophages but not with any other inflammatory cells or mesenchymal cells. Furthermore, the percentage of PDGF-positive macrophages in IPF was 3-fold increased in comparison to normal lung. In addition, the percentage of PDGF-positive macrophages was the same in fibrotic and nonfibrotic areas of IPF lungs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Experimental emphysema following intravenous injection of trypsin].

The injection of trypsin provokes a decrease of the circulating antiproteases. Its effect on an elastase-induced emphysema is negligible. Paradoxically, emphysema is quantitatively demonstrated in rats treated with trypsin alone: an influx of polymorphonuclear leucocytes into the lung is observed during the acute phase of experiment.

Animals↗
PubMed1990

[In situ hybridization: principles, methods and applications].

In situ hybridization is used to localize DNA or RNA sequences in tissue sections, single cells or chromosome preparations. The preparation and labeling of probes and the main steps of the technique are described and discussed together with its main applications.

Base Sequence↗
PubMed1989

[Man-nude mouse tissue chimera: characterization of cell population by in situ hybridization].

In situ hybridization with biotinated probes to total genomic DNAs as well as to the sequences ALu was performed on 13 cutaneous and 19 tumoral human grafts into nude mice. The dermis of cutaneous grafts is progressively overgrown by murine fibroblasts. Primary revascularization took place by development of anastomoses between the human and murine capillary beds. Well-differentiated human neurilemnal sheaths persisted in the grafts until the 6th month. Murine mononuclear cells, resembling Langerhans cells, penetrated the human epidermis. The cells of the fibrous capsules that enclosed the tumors were of mouse origin. Finally, transplantation of human tumors to mice resulted in the replacement of the endothelial and fibroblastic stromal human components by their murine counterparts.

Animals↗
PubMed1988

Intra and juxtavagal paraganglia: a topographical, histochemical, and ultrastructural study in the human.

The topographical, ultrastructural, and histochemical features of 23 human vagal paraganglia were analyzed. Nineteen of the 23 paraganglia were found in previously unreported sites; 18 of the 19 were in the cervical part of the nerve, between the carotid bifurcation and the superior thoraco-cervical inlet, and one paraganglion was located in the retrothyroidal part of the left inferior laryngeal nerve. The results of ultrastructural studies (2 cases), the histochemical and formaldehyde-induced-fluorescence studies (3 cases), and specific acetylcholinesterase activity (one case) demonstrate that these structures fulfill many of the modern criteria for paraganglionic tissue. In addition to paraganglia, single, isolated neurons or true micro-ganglia were always found along the trunk and branches of the vagus nerve when multiple sections were examined.

Adolescent↗
PubMed1988

Demonstration of glucose-6-phosphatase and peroxisomal catalase activity by ultrastructural cytochemistry in oval cells from livers of carcinogen-treated rats.

Oval cells isolated from livers of carcinogen-treated rats have morphologic and biochemical features of immature hepatocytes but seem to lack glucose-6-phosphatase (G6Pase) activity. The authors reinvestigated this question using histochemical methods for visualization of G6Pase activity by light and electron microscopy and the polyene antibiotic filipin to facilitate the penetration of the substrate. Oval cells that proliferate in the liver of animals receiving a carcinogenic diet (choline-deficient, containing 0.05% ethionine) contained G6Pase activity; 50-60% of nonparenchymal epithelial cells isolated from these livers by centrifugal elutriation contained G6Pase activity; and oval cell cultures displayed intense G6Pase activity at confluence but did not have detectable enzyme activity during exponential growth. These results and the demonstration that clofibrate induces peroxisomal proliferation in cultured oval cells strengthen the view that oval cells (or some subpopulation of cells in this compartment) are part of the hepatocyte lineage.

Animals↗
PubMed1987

About one case of vertebral chondroblastoma.

The authors report the case of a 9-year-old child which suffered from a chondroblastoma of the cervical spine. He had clinical signs of superior mediastinum compression with inflammation of the respiratory upper air-way. Surgery was performed. Diagnosis was established by the pathologist. The recurrence one year later was treated again by surgery and also by radiotherapy. Another recurrence four years later was fatal. The difficulties of the diagnosis and the appearance of recurrences in some cases of chondroblastoma are reviewed in the literature.

Cervical Vertebrae↗
PubMed1987

Spinal involvement in alveolar echinococcosis: assessment of two cases.

Two cases of spinal involvement in alveolar echinococcosis are reported. Conventional radiographs showed bone lysis and spondylitis; computed tomographic scans showed detail of local spread to the ribs, other vertebrae, and soft tissues. Differential diagnosis, which includes other infections and hydatidosis, is difficult, and the diagnosis may be suggested by evidence of a primary hepatic focus, geographic propensity to the infection, and laboratory findings.

Aged↗
PubMed1987

[Histo-immunolocalization of human and murine type I and III collagens in human cancers grafted to congenital athymic mice].

Seven human carcinomas and five sarcomas are microsurgically grafted to the nude mouse. We demonstrate with antibodies to human and murin Type I and III collagens that the capsule of the grafted human tumors and the intratumoral perivascular collagen are always of murin origin. Mouse Type I and III collagens take progressively the place of their human counterparts in the extracellular matrix of carcinoma. In contrast the intratumoral collagens of sarcomas are ever of human nature. The murin collagen, probably induced by the tumors, is perhaps one of the factors which prevents in the nude mouse the metastasis of the human grafted tumors.

Animals↗
PubMed1984

Resection followed by vascularized bone autograft in patients with possible recurrence of malignant bone tumors after conservative treatment.

In conservative treatment of malignant bone tumors, assessment of the local condition is difficult. The radiological changes seen in the irradiated tumor and the frequent occurrence of pathological fractures at this site may give rise to the fear that the tumor has relapsed. Resection of the whole of the involved bone is the best way to assure adequate local control but the extent of the bone defect and the bad local conditions secondary to irradiation make reconstruction hazardous. In two patients (one with Ewing's sarcoma of the femur and one with osteogenic sarcoma of the humerus) the authors used a free, vascularized fibular graft for the reconstruction having obtained consolidation of the limb after resection of the irradiated tumor, with preservation of its function. The encouraging results obtained have suggested a conservative attitude as primary treatment of specific malignant bone tumors.

Adolescent↗
PubMed1984

[Acute edema of the lung in eclampsia].

In 6 cases of eclampsia in the course of pre and post-partum, we could observe neurological disorders associated with acute pulmonary oedema with acute respiratory distress occurring 5 to 72 hours after the first convulsive crisis. Hemodynamic check-up provided various results: 3 cases corresponded to A.P.O resulting from a lesion, with normal capillary pressure. In 3 other cases, there was hemodynamic oedema (overloading with high flow and hypervolemia in one case, myocardial incompetence with hypovolemia in an other case revealed by test filling in a third case). There were clinical signs of left ventricular failure in 4 case. Post-mortem investigations (5 cases) revealed unimportant ultrastructural alterations of myocardium only in 2 cases. Pulmonary histopathological investigations (5 cases) were the investigations carried out in case of oedema resulting from lesions with interstitial and alveolar oedema, hyaline membranes, alteration of pneumocytes, and intra-capillary thrombi. Mendelson's syndrome which was always discussed could be eliminated. The syndrome of respiratory distress was certainly connected with more or less generalized microcirculatory disorders (microembolism with hyperpermeability) connected with hemostasis disorders and cerebral manifestations.

Acute Disease↗