PubMed Health⌕ Search

Biomedical subjects

M Bourges

Publications and source records attributed to M Bourges.

At least 19 recordsLinked to original sources
PubMed1998

G2 accumulation and melanin overproduction in malignant melanocytes treated with a new nitrosourea.

Cystemustine (N'-(2-chloroethyl)-N-(2-(methylsulphonyl)ethyl)-N'-nitrosourea), a new anticancer chloroethylnitrosourea (CENU) is being tested in a phase II clinical trial of disseminated melanoma. The antitumour effect of this drug is mainly due to DNA damage in malignant melanocytes. Recently, we have shown that this damage can induce apoptosis in some melanoma cell lines. In others, apoptosis is not clearly observed, although there is a strong cytostatic effect. In this paper, we have characterized the cytological effect of cystemustine on murine malignant melanocytes (B16 cell line) which are resistant to apoptosis induced by this CENU. The results show that 3 days after cystemustine treatment, these melanocytes had accumulated in phase G2 of the cell cycle. There was then a strong morphological modification during a long cytostatic phase up to 30 days after treatment. During this cytostatic phase, there was uncontrolled DNA synthesis and marked swelling. Also, tyrosinase activity, melanin content and the number of mature melanosomes were greatly increased. These results suggest that when malignant melanocytes are not able to undergo apoptosis after treatment with CENU, they accumulate in G2 and this is followed by enhancement of melanogenesis.

Animals↗
PubMed1996

Histochemical and ultrastructural study of diffuse melanoderma after bone marrow transplantation.

Hyperpigmentation is a well-recognized feature of cutaneous graft-versus-host disease (GVHD), and is usually restricted to sites where lichenoid or sclerodermiform lesions have occurred. Since 1975, two of 745 patients treated by allogeneic bone marrow transplantation in our institution have developed diffuse melanoderma which differed considerably from the classic presentations. They both developed acute GVHD, then lichen planus-like chronic lesions and diffuse melanoderma. Histology of biopsies of the pigmented skin showed intense pigment deposition in the basal and suprabasal layers, and in dermal macrophages. On split-dopa, melanocyte counts were 98 and 93 per field, respectively. Electron microscopy showed melanocytes protruding into the dermis, and dark melanosomes in all epidermal layers and in macrophages. These findings were suggestive of post-inflammatory hyperpigmentation. In bone marrow recipients, de novo melanoderma is a rare event which could represent a feature of cutaneous GVHD in pigmented subjects.

Adolescent↗
PubMed1995

Calcitonin secretion, C cell differentiation and proliferation during the spontaneous development of murine medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC), a C cell neoplasm, synthesizes large amounts of calcitonin (CT), its biological marker. However, in some cases with a poor prognosis, MTC is associated with low basal CT levels owing to a decrease in the thyroid CT content. Using a murine model of human MTC, we studied the relationships between CT biosynthesis, C cell proliferation, and the circulating CT level during MTC progression. Cell proliferation was revealed by autoradiography of radioactive thymidine incorporation in dividing nuclei, after CT or CT mRNA detection by immunocytochemistry (ICC) or in situ hybridization (ISH). All rat thyroids showed a severe hyperplasia of C cells containing significant amounts of CT and CT mRNA, and a very low mitotic index. Tumours were found in 68% of the thyroids. In the strongly immunoreactive small nodules (ICC+), many labelled nuclei were observed. Subsequently some nodular cells, still containing detectable CT mRNA (ISH+), were not detected by immunocytochemistry (ICC-) owing to a dramatic decrease in secretory granules. Their mitotic index increased, and a rise of the basal CT plasma level was noted. These ISH+, ICC- tumour MTC cells represent a modified aggressive tumour C cell population exhibiting an increased ability to proliferate and were detected by the rise in the basal circulating CT level.

Animals↗
PubMed1994

[Evolutionary aspect of spinal ligaments in the human fetus].

Preliminary histological observations concerning interspinal ligament, at level T1 T2 and far the 14th, 24th and 37th post-ovulatory (P.O.) weeks, are presented here. In an histological, then biological context, these observation take place into an evolutive study of the muscular and ligamentous material of the human fetus spine. The paraffin included biopsy sections were examined after being colored with Mallory blue and picro-indigo-carmin chlorhydric orcein. After 14 weeks P.O., an heterogeneous structure appears with muscular, mixt and fibrous fascicules in a polygonal cellulo-fibrous network. After 24 weeks P.O., the structure is entirely fibrous, in a long, plexiform web. The evolution become more acute after 37 weeks P.O. After chlorhydric orcein coloration, no elastic fibers were observed in the collagen network, during the first two stages of observation cholorhydric orcein coloration, however, revealed a small quantity of them, 37 weeks after ovulation.

Biological Evolution↗
PubMed1990

Adhesion of enterotoxigenic Escherichia coli to the human colon carcinoma cell line Caco-2 in culture.

Enterotoxigenic Escherichia coli (ETEC) strains possessing colonization factor antigen I (CFA/I), CFA/II, CFA/III, and antigen 2230 were tested for their ability to adhere to the following cell lines: HeLa, HEp-2, HRT 18, Hutu 80, MDBK, MDCK, Vero, and Caco-2. ETEC strains adhered only to the Caco-2 cell line. Irrespective of the known adhesive factors, the ETEC strains that adhered to the brush border of human enterocytes also adhered to the Caco-2 cell line. The negative variants, which were cured of the plasmid encoding the adhesive factor, did not adhere. Adhesion of ETEC strains no longer occurred when the Caco-2 cells were pretreated with the homologous colonization factor antigen or when the bacterial cells were pretreated with homologous antibodies raised against the adhesive factors. This indicates that this adhesion is specific and that a different receptor exists for each type of adhesion factor. Electron micrographs of cross sections of the monolayer showed that the adhesion of ETEC strains to the brush border microvilli does not induce any lesion. Therefore, the Caco-2 cell line behaves in the same way as human enterocytes do.

Antigens, Bacterial↗
PubMed1989

A simplified method of tissue processing for immunostaining with good preservation of antigens and morphology.

A simple and rapid method of tissue processing has been developed for immunostaining. Human and murine tissues were fixed in a PVA solution, diluted in a special buffer and embedded in paraffin or stored in a stock solution before preparing frozen sections. By indirect immunofluorescence, several antigens (collagen isotypes, laminin and fibronectin) were better demonstrated in the samples processed by the present method than with frozen or deparaffinized sections. In addition, this method allows a histological preservation quite identical to that seen in classical histology.

Animals↗
PubMed1988

Eosinophilic cellulitis (Wells' syndrome): ultrastructural study of a case with circulating immune complexes.

A 42-year-old woman was observed during 3 bouts of eosinophilic cellulitis over a 6-year-period. Skin biopsies were taken at each relapse and processed for histological, immunofluorescent and ultrastructural studies. Histologically the eosinophilic infiltrate extended to the deep dermis and the subcutaneous fat. High levels of circulating immune complexes, and complement and IgG deposits around the vessels were detected for as long as the cutaneous lesions lasted. Under the electron microscope eosinophils were numerous, half of them degranulated and some granules had a double cristal core. No injury to the vessel walls was observed. The 3 recurrences occurred respectively after lincomycin, nesdonal, acetyl salicylic acid and pholcodin ingestion and responded to sulfone and steroid therapy.

Adult↗
PubMed1985

Biomechanical properties of spinal ligaments and a histological study of the supraspinal ligament in traction.

This paper reports the results of a biomechanical study of 43 human spinal ligaments from fresh cadavers and living subjects. Tensile tests were performed with an original testing machine. The tension load and relaxation were applied at the same constant slow rate (1 mm min-1) on entire ligaments. In order to avoid ligament injuries, fixation in the apparatus was on the bone held in clamps specifically designed for each bone, never the ligament itself or its bony attachments. All the load-deformation curves had a sigmoid shape and during load-unload cycles ligaments exhibited elastic properties. This was particularly evident for the ligamentum flavum. The intertransverse posterior longitudinal ligament and the ligamentum flavum were the most resistant. The elongation-tension curve pattern may be explained by the microscopic architectural change that was studied in supraspinous ligament.

Adult↗
PubMed1985

Subcutaneous sclerosis with fasciitis and eosinophilia after phytonadione injections.

We treated a case of subcutaneous sclerosis after phytonadione injections (Texier's disease) that was noteworthy for two associated features: sclerosis with inflammatory infiltrate in the fascia, and blood eosinophilia. A peculiar type of cutaneous sclerosis after phytonadione injections was described in 1972. The sclerosis in that case was first confined to the buttocks, progressively extended to both thighs, and slowly resolved. In the 38 reported cases, neither sclerosis of the fascia nor blood eosinophilia was observed.

Drug Eruptions↗
PubMed1985

[Pulmonary lesions following bone marrow graft. Study of 35 cases].

Lung biopsy of 35 patients with interstitial pneumonitis following bone marrow transplantation (BMT) have been studied histologically, ultrastructurally and by immunofluorescence. Among infectious diseases, cytomegaloviruses (CMV) are the more frequently found, whereas Pneumocystis carinii infections are more frequently found in immunocompromised hosts without BMT. CMV infections are related to severe chronic graft-versus-host disease in allogenic or mismatched BMT. Hemorrhagic pulmonary oedema and vascular damage might be the consequence of high doses of cyclosporin A or of disseminated intravascular coagulation. Granulomatous and fibrosing lesions corresponded in 2 cases to an eosinophilic pneumonitis and in 11 cases to an "idiopathic" diffuse interstitial pneumonitis. 2 patients had concomitant diffuse lung fibrosis, sclerotic plaques of the skin and Sjögren-like syndrome. The pulmonary and cutaneous scleroses had common features in the types of collagen and in the composition of the infiltrate. Both fibroses might result from a common pathogenic mechanism related to an immunologic conflict between the lymphocytes of the graft and the cells from the host tissues.

Adolescent↗
PubMed1984

Immunohistologic and ultrastructural study of the sclerotic skin in chronic graft-versus-host disease in man.

Thirteen skin biopsies were performed on 8 patients at different stages of skin sclerosis in chronic graft-versus-host disease (GVHD). On the same skin biopsies an immunostaining with antibodies directed against Types I and III procollagen, Types I, III, IV, V collagen, and laminin, and an ultrastructural study were performed. Alterations were observed at the dermal-epidermal junction and in the superficial dermis with a large deposit on Type III procollagen in the incipient scleroses and of Type I procollagen in the oldest ones. In this sclerotic superficial dermis, collagen fibers of irregular diameter were associated with mast cells and active fibroblasts, macrophages, and lymphocytes in close contact. The skin sclerosis in chronic GVHD might be considered a form of cutaneous fibrosis with features of excessive tissue repair related to an immunologic reaction between lymphocytes of the graft and tissue host cells.

Adolescent↗
PubMed1983

[Refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreatic dysfunction. Study of a new case].

The case of an infant with bone marrow dysfunction and exocrine pancreatic deficiency is reported. Bone marrow dysfunction presented at birth, with a refractory sideroblastic anemia later associated with neutropenia and thrombocytopenia. Erythroid and myeloid precursors had a marked cytoplasm vacuolization and very poor in vitro growth. The exocrine pancreatic deficiency was shown by the pancreozymin-secretin stimulation test and by the study of fat digestion. This case report is different from Shwachman's syndrome, but similar to a syndrome of unknown etiology, recently described by Pearson in 4 children. The normality of immune investigations and of the culture of T lymphocyte precursors, in our patient, shows that the bone marrow dysfunction spares the lymphoid lineage. The simultaneous occurrence of bone marrow and pancreatic cells dysfunction suggests either a process acquired during embryonic life, or a gene mutation with pleiotropic effects.

Anemia, Sideroblastic↗
PubMed1981

Eosinophilic fasciitis. Ultrastructural study of an early biopsied case.

A 55-year-old women with eosinophilic fasciitis was biopsied 8 weeks after the onset of her illness. Under the electron microscope the changes were almost exclusively located in the fascia with many active fibroblasts, accumulation of protocollagen fibrils (10-50 A diameter), elastic fibre remodelling and numerous degranulating mast cells. The inflammatory infiltrate was dense and mostly composed of lymphocytes and plasma cells, with 16% eosinophils. The connective tissue changes may be part of a healing process following microinjury of the fascia. However, large numbers of lymphocytes and plasma cells are unusual in the healing process and are more common in the cellular reaction of morphea. Nevertheless, the absence of macrophages in subcutaneous fat, together with large number of eosinophils in the fascia may be considered to be distinctive features of eosinophilic fasciitis.

Biopsy↗
PubMed1981

The lichen planus like and sclerotic phases of the graft versus host disease in man: an ultrastructural study of six cases.

Skin biopsies from 6 patients with chronic graft-versus-host disease (GVHD) were studied ultrastructurally. The 6 patients experienced an early lichenoid phase 65-135 days after the graft and 3 of them progressed to a late sclerotic phase 200-340 days after the grafting Damage to the basal membrane and to the keratinocytes of the basal layer and low spinous layers, and presence of epidermal regenerative cells were features common to the lichenoid phase of chronic GVHD and idiopathic lichen planus. The late sclerotic phase of GVHD with persistence of basal cell injury, normal periodicity and structure of the collagen fibres and numerous active fibroblasts in the upper third of the dermis were findings that distinguished GVHD from scleroderma. Satellite cell necrosis, i.e. lymphocyte satellites of necrotic keratinocyte, was observed in the two phases of chronic GVHD. Thus at the ultrastructural level the early phase of chronic GVHD mimics lichen planus, but the late sclerotic phase is distinct from scleroderma.

Adult↗
PubMed1981

[Ultrastructural similarities between the planus-like reaction of the graft versus host disease and the idiopathic lichen planus (author's transl)].

An ultrastructural study was performed on skin biopsies of eight patients with lichenoid eruption of chronic graft-versus-host disease (GVHD). The lichenoid eruption is similar to idiopathic lichen planus with the injury of the basal cells, the distribution of the numerous colloid bodies, and the presence of regenerative cells. Lymphocytes satellites of injured keratinocytes were observed in those lichenoid eruptions, as well as in the acute phase of GVHD. The numerous mast cells in the lichenoid eruption of GVHD may be related to the connective tissue changes of the patients progressing to a late sclerotic phase of chronic GVHD.

Adult↗