Michel Le Hir

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This report deals with the distribution, morphology and specific topical relationships of bone-marrow-derived cells (free cells) in the spinal meninges and dorsal root ganglia of the normal rat. The morphology of these cells has been studied by transmission and scanning electron microscopy. Cells expressing the major histocompatibility complex (MHC) class(More)
Fibrosis is considered as a central factor in the loss of renal function in chronic kidney diseases. The origin of fibroblasts and myofibroblasts that accumulate in the interstitium of the diseased kidney is still a matter of debate. It has been shown that accumulation of myofibroblasts in inflamed and fibrotic kidneys is associated with upregulation of(More)
A monoclonal antibody IgG, has been raised against ecto-5′-nucleotidase purified from rat kidney homogenate. The specificity of the antibody was verified by immunoprecipitation. The distribution of the corresponding antigen in the rat kidney was studied by immunocytochemistry (FITC and PAP technique) in 1 μm thick cryostat sections. The antibody reacted(More)
Ecto-5′-nucleotidase is anchored at the outer surface of cell membranes and thus its reaction product adenosine is released into the extracellular space. Extracellular adenosine displays via specific receptors a wide range of physiological effects in heart. There are discrepancies in the literature concerning the distribution of ecto-5′-nucleotidase in(More)
In the kidney a striking parallel exists between the expression of ecto-5′-nucleotidase and of erythropoietin by renal fibroblasts. It was therefore hypothesized that the expression of ecto-5′-nucleotidase in fibroblasts might be controlled by oxygen tension. In order to test this hypothesis, we examined the distribution of the enzyme in a tissue which(More)
The kidney is the main site of erythropoietin (EPO) formation. Oxygen sensing in the kidney itself plays a major role in the control of EPO synthesis. By in situ hybridization it has been established that the EPO-producing cells are situated in the interstitium of the cortical labyrinth, but they have not been precisely identified. Morphological findings(More)
The activities of enzymes of the tricarboxylic acid cycle were measured in order to compare the respiratory capacity in different parts of the nephron of the rat. Oxoglutarate dehydrogenase, citrate synthase and isocitrate dehydrogenase were assayed in single nephron segments dissected out of freeze-dried cryostat sections. The activities of the three(More)
We searched for morphological evidence to support the hypothesis that stem cells are responsible for renal tubular cell proliferation. The rationale of the study was that if proliferation relies on progenitors, mitotically active cells should be less differentiated than their neighbors. As the retention of the thymidine analog BrdU has been the only(More)
The transport of adenosine into brush border membrane vesicles from rat kidney is demonstrated. A first, rapid stage of transport is completed by 20 s. It is stimulated by a gradient of sodium. The effect of the concentration of adenosine in the low micromolar range on the initial rate of uptake indicates a saturability. An apparent Km of 1.48 μM and a Vmax(More)