Stephen T. Koury

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We have used in situ hybridization to determine the localization and distribution of cells expressing the erythropoietin (EPO) gene in kidneys of rats exposed to reduced oxygen tensions to characterize the control of renal EPO formation during hypoxic hypoxia. Animals were subjected to severe hypoxia (7.5% O2) for 4, 8 and 32 hours to assess changes related(More)
Spectrin-like proteins are found in a wide variety of non-erythroid cells where they generally occur in the cell cortex near the plasma membrane. To determine the intracellular distribution of alpha-spectrin (alpha-fodrin) in lymphocytes, we have developed an immunoperoxidase method to localize this protein at the ultrastructural level. Of considerable(More)
We have used murine splenic erythrolasts infected with the anemia-inducing strain of Friend virus (FVA cells), as an in vitro model to study cytoskeletal elements during erythroid maturation and enucleation. FVA cells are capable of enucleating in suspension culture in vitro, indicating that associations with an extracellular matrix or accessory cells are(More)
BACKGROUND Paraoxonase 1 (PON1) phenotype is a better predictor of atherosclerosis risk than are PON1 genetic polymorphisms alone. Larger studies are required to determine the role of PON1 and there is a need for standardized PON1 assays between laboratories. METHODS We have adapted 5 enzyme kinetic assays for high-throughput automated analysis of PON1(More)
In situ hybridization was used to localize the cells that produce erythropoietin (EP) in anemic murine kidneys. Kidneys from anemic and nonanemic mice were fixed and processed for paraffin embedding. Sections were hybridized with a 35S-labeled RNA probe complementary to mRNA coding for EP. An uncommon, but specific type of cell was intensely labeled in the(More)
Fibrosis is a common pathological feature observed in muscle from patients with Duchenne muscular dystrophy (DMD). In the dystrophic (mdx) mouse model of DMD, the diaphragm is more severely affected than other skeletal muscles. The level of transforming growth factor-beta1 (TGF-beta1), an inflammatory cytokine, is significantly elevated in mdx diaphragm.(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)
In situ hybridization using antisense RNA probes was used to localize cells that produce erythropoietin (EPO) in the livers of anemic transgenic mice expressing the human EPO gene and in livers of anemic nontransgenic mice. In transgenic mice bled from a hematocrit of 55% to one of 10%, hepatocytes surrounding central veins synthesized large amounts of(More)
Synthesis of erythropoietin, the primary humoral regulator of erythropoiesis, in liver and kidney is inducible by anemia or hypoxia. Analysis of human erythropoietin gene expression in transgenic mice revealed that sequences located 6-14 kilobases 5' to the gene direct expression to the kidney, whereas sequences within the immediate 3'-flanking region(More)
The cellular origins of erythropoietin were investigated in the rat using a probe derived from a cloned rat erythropoietin cDNA. In anaemic-hypoxic rat liver, in situ hybridization detected erythropoietin mRNA primarily in hepatocytes and less frequently in nonparenchymal sinusoidal or perisinusoidal liver cells. An RNase protection assay was used to(More)