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The mitochondrial enzyme 25-hydroxyvitamin D 3-1␣-hydroxylase (1␣-hydroxylase) plays an important role in calcium homeostasis by catalyzing synthesis of the active form of vitamin D, 1,25-dihydroxyvi-tamin D 3 , in the kidney. However, enzyme activity assays indicate that 1␣-hydroxylase is also expressed in a variety of extrarenal tissues ; recent cloning(More)
Parathyroid hormone-related peptide (PTHrP) and the parathyroid hormone/parathyroid hormone-related peptide (PTH/PTHrP) receptor are important developmental regulators of cell growth and differentiation in some organs. In lung, both the peptide and the receptor are expressed early in development and in alveolar cells in adults. In adult alveolar cells,(More)
Baboons from some families have a higher concentration of plasma high density lipoproteins (HDL) on a chow diet and accumulate large HDL (HDL1) when challenged with a high cholesterol and high saturated fat (HCHF) diet. HDL1 from high HDL1 animals contained more (1.5-fold) cholesteryl ester than HDL (HDL2 + HDL3) from high or low HDL1 animals. HDL from high(More)
T1alpha, a differentiation gene of lung alveolar epithelial type I cells, is developmentally regulated and encodes an apical membrane protein of unknown function. Morphological differentiation of type I cells to form the air-blood barrier starts in the last few days of gestation and continues postnatally. Although T1alpha is expressed in the foregut(More)
The transcription factor Sp1 plays an important regulatory role in transactivation of the lung type I cell differentiation gene T1alpha. Like other lung cells, type I cells may encounter changes in oxygen concentration during the lifetime of the organism. We found that exposure of mice to hyperoxia rapidly increases expression of T1alpha and other type I(More)
Fluid-filled lumina of fetal rat lungs contain lamellar bodies (LBs) as well as tubular myelin (TM), both of which are thought to be stores of phospholipid-rich pulmonary surfactant. The alveolar epithelium is believed to secrete LBs, but neither the origin nor the mechanism of TM formation is entirely certain. The main objective of this study was to(More)
The main objective of this study was to determine the pathways by which horseradish peroxidase (HRP) can cross the endothelium of muscle capillaries. Specimens of mouse diaphragm were fixed for cytochemical analysis at various intervals after intervenous injection of 0.5 mg HRP, at 4 min after intervenous injection of varied amounts of HRP, and at 4 min(More)
In the lung, caveolin-1 is expressed in both type I alveolar epithelial and endothelial cells where it is hypothesized to modulate molecular signaling activities and progression of tumorigenesis. Developmentally, caveolin-1alpha is expressed in fetal lung endothelial, but not epithelial, cells; in adult lung, both cell types express caveolin-1alpha. To test(More)
In this study we attempted to identify a morphologic counterpart of the small pore of muscle capillaries. The existence of such a pore has been postulated by physiologists to explain the permeability of muscle capillaries to small macromolecules. We injected mice intravenously with microperoxidase (MP) and fixed specimens of diaphragm at intervals of 0-250(More)