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Biomedical subjects

M Baslé

Publications and source records attributed to M Baslé.

12 recordsLinked to original sources
PubMed2000

Activation of the Jak/Stat signal transduction pathway in GH-treated rat osteoblast-like cells in culture.

In this study, activation of the Jak/Stat signaling pathway was followed upon growth hormone (GH) stimulation, using the rat osteosarcoma cell-line UMR-106.01 that expresses high affinity GH receptors. The results show a GH-induced and sustained phosphorylation of Jak2 and Stat5 on tyrosine residues. The tyrosine phosphorylation status of Jak2 was increased in a dose-dependent manner. In contrast to Jak2, tyrosine phosphorylation of Stat5, also elicited at 42 ng/ml GH, remained unchanged when GH concentration was raised up to 4200 ng/ml. DNA binding activity of Stat5 was also observed in response to GH. However, GH was unable to cause transactivation of reporter gene constructs harboring Stat5 binding sites (the GHREII from the rat spi 2.1 gene promoter, and the LHRE from the rat beta-casein gene promoter), except in cells transiently transfected with either Stat5 cDNAs or the rat GHR cDNA. Altogether the results suggest that UMR-106.01 cells exhibit original features of the GH-dependent Jak/Stat signaling pathway.

Animals↗
PubMed2000

Syndecan-2 is involved in the mitogenic activity and signaling of granulocyte-macrophage colony-stimulating factor in osteoblasts.

We previously showed that granulocyte-macrophage colony-stimulating factor (GM-CSF) binds to heparan sulfate proteoglycans expressed at the surface of osteoblastic cells and that the mitogenic activity of this cytokine is dependent on the presence of fully sulfated proteoglycans. In this study, we determined if GM-CSF interacts with syndecans, a family of cell surface heparan sulfate proteoglycans. Human primary osteoblasts were found to express syndecan-2 and -4 but few syndecan-1 transcripts and proteins. Recombinant human GM-CSF coupled to biotin was found to bind to syndecan-2. Immunocytochemical transmission electron microscope analysis showed co-localization of syndecan-2 and GM-CSF at the cell membrane surface. Syndecan-2 also co-localized at the cell surface and co-immunoprecipitated with the GM-CSF receptor alpha chain, suggesting a strong interaction between the cytokine, its receptor, and syndecan-2. Phosphorylation of tyrosine residues in syndecan-2 associated with the alpha chain of the GM-CSF receptor was increased after cell stimulation by GM-CSF. Antisense oligonucleotides that reduced specifically the expression of syndecan-2 inhibited the mitogenic activity of GM-CSF and the activation of extracellular signal-regulated kinase-1 induced by the cytokine. Our results indicate functional interactions between syndecan-2 and GM-CSF in osteoblasts, and we propose that syndecan-2 plays a role as a co-receptor for this cytokine.

Base Sequence↗
PubMed2000

Gastric mucosal surface in cirrhosis evaluated by magnifying endoscopy and scanning electronic microscopy.

BACKGROUND AND STUDY AIMS: Gastric mucosa may have several tiny patterns in portal hypertension. In this prospective study, we used magnifying endoscopy and scanning electron microscopy (SEM) to better characterize the morphology of gastric mucosa in patients with cirrhosis, and we evaluated the diagnostic accuracy of magnifying endoscopy. PATIENTS AND METHODS: Videotapes of gastric mucosal patterns from 39 cirrhotic patients and 20 control patients were blindly evaluated by the same observer using magnifying endoscopy (magnification x 25) and conventional endoscopy. SEM was performed in 12 other patients. The basic anatomical entities of the gastric architecture on conventional endoscopy were the gastric area in control patients and the mosaic pattern in patients with cirrhosis. RESULTS: With regard to the prevalence of endoscopic patterns in the antrum, the mosaic pattern was more frequent in cirrhotic patients. In the body, the mosaic pattern, white spots, and red marks were significantly more frequent in cirrhotic patients, whereas gastric areas were more frequent in control patients. Concerning the contributions of the techniques, significantly more gastric areas were identified by magnifying endoscopy than by conventional endoscopy. However, in multivariate analysis, only conventional endoscopy with esophageal varices had significant independent diagnostic accuracy for cirrhosis, and magnifying endoscopy of mucosal signs did not add any significant information. SEM did not improve discrimination between control and cirrhotic patients. CONCLUSIONS: Magnifying endoscopy provides more details of the mucosa, thus improving the delineation of gastric mucosal morphology. However, magnifying endoscopy has little clinical value in cirrhosis since it does not improve on the accuracy of conventional endoscopy for the diagnosis of cirrhosis.

Adult↗
PubMed1993

[Migratory algodystrophy of the lower limbs involving the foot and complicated by two fatigue fractures. An histological bone study].

A 62 year old male developed transient osteoporosis algodystrophy successively in several sites of the lower limbs (8 episodes of involvement of one or two sites over an 8-year period) three years after surgery for a chromophobic pituitary adenoma. Two stress fractures developed, during the sixth and seventh years, respectively, in bones previously affected by osteoporosis. A biopsy specimen from the distal tibia showed thin bone trabeculae and reduced cellular activity. The only etiologic factor was the patient's psychological profile characterized by anxiety and introversion.

Bone and Bones↗
PubMed1988

Influence of blood calcium on calcitonin receptors in isolated chick osteoclasts.

Isolated osteoclasts obtained from young chickens fed a normal (+Ca) or deficient (-Ca) calcium and vitamin D diet for 3 weeks, were studied for their ability to bind salmon calcitonin (sCT). Osteoclasts obtained from -Ca chickens, when incubated with 0.1 mumol sCT/l, doubled cyclic (c)AMP production and retracted from a glass support, as observed by scanning electron microscopy. The presence of receptors was also demonstrated by autoradiography and competition analysis of 125I-labelled sCT binding. The number of receptors per cell was 0.9 +/- 0.1 x 10(4). In contrast, osteoclasts obtained from +Ca chickens did not increase cAMP production and did not retract in the presence of 0.1 mumol sCT/l. No specific binding of 125I-labelled sCT could be demonstrated on these osteoclasts. Plasma levels of calcium and calcitonin were measured in +Ca and -Ca chickens. The plasma concentration of calcium was markedly lower at 3 weeks in -Ca than in +Ca chickens. The plasma concentration of calcitonin was decreased in -Ca chickens compared with +Ca chickens at the first week and kept decreasing during the 3 weeks. These results strongly support the hypothesis that calcium and vitamin D intake regulate plasma calcitonin levels in chickens, and that calcitonin receptors can be detected on chicken osteoclasts only when blood calcium is decreased by a diet deficient in calcium and vitamin D.

Animals↗
PubMed1983

[Paget's bone disease. Preliminary serological study].

A serological study has been carried out in Paget's bone disease where the etiology still remains uncertain. Previous work on patients with the disease revealed specific osteoclast inclusions that could be linked to the presence of a virus of the paramyxovirus group. Conventional methods for exploring humoral immunity reveal no great differences in the concentration of antibodies against the various viral strains tested on sera from 46 patients with Paget's bone disease and from 46 paired controls. The viral origin of Paget's bone disease is reconsidered in the light of the results obtained. The eventuality of sub-threshold viral infection and the possible action of incomplete or defective virus leading to the chronic nature of the disease are discussed.

Aged↗
PubMed1983

[Paget's bone disease. Preliminary serological study].

A serological study has been carried out in Paget's bone disease where the etiology still remains uncertain. Previous work on patients with the disease revealed specific osteoclast inclusions that could be linked to the presence of a virus of the paramyxovirus group. Conventional methods for exploring humoral immunity reveal no great differences in the concentration of antibodies against the various viral strains tested on sera from 46 patients with Paget's bone disease and from 46 paired controls. The viral origin of Paget's bone disease is reconsidered in the light of the results obtained. The eventuality of sub-threshold viral infection and the possible action of incomplete or defective virus leading to the chronic nature of the disease are discussed.

Aged↗
PubMed1976

Osteoclast ultrastructure in Paget's disease.

The ultrastructural study of osteoclasts in biopsies from 12 patients with Paget's disease reveals several cytological anomalies. In Particular, nuclear inclusions, consisting essentially of striated filaments about 150 A in diameter, often organized in bundles and sometimes in paracrystalline arrays, appear to be specific to the disease. Morphologically, the inclusions are remarkably similar to those observed in various cases of viral attack, and the hypothesis of the action of a possible external agent in Paget's disease cannot be ruled out.

Cell Nucleus↗