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Amniotic fluid analysis of microvillar enzymes, including alkaline phosphatase (ALP) total activity and ALP isoenzymes, has been widely experimented with and used for the prenatal diagnosis of cystic fibrosis in the second trimester of gestation. Since the development of cystic fibrosis molecular
A monoclonal antibody (AAP-1), specific for the intestinal isoenzyme of alkaline phosphatase (ALP), has been used to develop an immunoassay for amniotic fluid samples. Values in the immunoassay correlated closely with those obtained by direct determination of phenylalanine-inhibitable ALP. A panel
Second-trimester amniotic fluid contains two major alkaline phosphatase (ALP) isoenzymes, one susceptible to inhibition by phenylalanine and the other to inhibition by homoarginine. The proportions of these isoenzymes are constant between 15 and 21 weeks of gestation. In pregnancies where the fetus
Utilizing their differential susceptibilities to inhibitors and heat, we determined the amounts of the placental, liver, and fetal-intestinal isoenzyme forms of alkaline phosphatase in 143 samples of normal amniotic fluid obtained at 14 to 18 weeks' gestation (1). For reliable results, it was
The membrane glycoprotein enzyme, alkaline phosphatase was induced in cultured human fibroblasts by dibutyryl cyclic AMP, sodium butyrate, the serum glycoprotein fetuin, the Tamm-Horsfall urinary glycoprotein, and by a number of inhibitors of DNA synthesis. The uninduced basal enzyme activity
Some cystic fibrosis transmembrane conductance regulator (CFTR) mutations, such as G551D, result in a correctly localized Cl- channel at the cell apical membrane, albeit with markedly reduced function. Patch-clamp studies have indicated that both phosphatase inhibitors and
cAMP-dependent phosphorylation activates the cystic fibrosis transmembrane conductance regulator (CFTR) in epithelia. However, the protein phosphatase (PP) that dephosphorylates and inactivates CFTR in airway and intestinal epithelia, two major sites of disease, is not certain. We found that in
The specific activities of alpha-D-mannosidase, beta-glucuronidase, beta-D-fucosidase, acid and alkaline phosphatase were studied in meconium from infants with cystic fibrosis (CF) and control subjects. The study revealed significant variations in the specific activity of the enzymes except for acid
Cystic fibrosis transmembrane conductance regulator (CFTR) chloride channels are rapidly deactivated by a membrane-bound phosphatase activity. The efficiency of this regulation suggests CFTR and protein phosphatases may be associated within a regulatory complex. In this paper we test that
Alkaline phosphatase (ALP) activities were compared in fibroblasts from three cystic fibrosis patients and two normal controls after culturing the cells in normal growth medium and in medium containing Tamm-Horsfall glycoprotein, isoproterenol, and theophylline. No consistent alterations in ALP
Cystic fibrosis transmembrane conductance regulator (CFTR) is a regulated Cl- channel; in secretory epithelia, it is located in the apical membrane where it regulates transepithelial Cl- secretion. Previous studies have shown that cAMP-dependent protein kinase (PKA) can phosphorylate and activate
The high-Mr isoenzyme of alkaline phosphatase (AP, EC 3.1.3.1), a highly sensitive index to cholestasis, was measured by liquid chromatography in 45 patients with cystic fibrosis. Results of serum tests for liver dysfunction--including gamma-glutamyltransferase, aspartate aminotransferase, alanine
A direct interaction of the regulatory domain (R domain) of the cystic fibrosis transmembrane conductance regulator protein (CFTR) with PR65, a regulatory subunit of the protein phosphatase 2A (PP2A), was shown in yeast two hybrid, pull-down and co-immunoprecipitation experiments. The R domain could
Microvillar enzymes (disaccharidases, alkaline phosphatase, and gamma-glutamyltransferase) were assayed in amniotic fluid from pregnancies with normal and abnormal fetuses to determine their specificity and reliability for the prenatal detection of intestinal obstructions and cystic fibrosis. All
It is confirmed that the level of alkaline phosphatase in fibroblasts derived from cystic fibrosis patients can be induced many-fold by growing the cells in the presence of Tamm-Horsfall glycoprotein. It is further shown that normal fibroblasts produce a "CF corrective factor" which markedly