Search results for "Isoenzyme"
showing 10 items of 247 documents
Association of low 25-hydroxyvitamin D concentrations with elevated parathyroid hormone concentrations and low cortical bone density in early puberta…
2003
Background: Very few studies have evaluated both parathyroid hormone (PTH) and 25-hydroxyvitamin D [25(OH)D] and their effects on bone mass in children. Objective: We studied the associations of serum 25(OH)D and intact PTH (iPTH) with bone mineral content (BMC) and bone mineral density (BMD) at different bone sites and the relation between serum 25(OH)D and iPTH in early pubertal and prepubertal Finnish girls. Design: The subjects were 10‐12-y-old girls (n = 193) at Tanner stage 1 or 2, who reported a mean (± SD) dietary calcium intake of 733 ± 288 mg/d. 25(OH)D, iPTH, tartrate-resistant acid phosphatase 5b (TRAP 5b), urinary calcium excretion, BMC, areal BMD, and volumetric BMD were asses…
Human Upcyte Hepatocytes: Characterization of the Hepatic Phenotype and Evaluation for Acute and Long-Term Hepatotoxicity Routine Testing
2016
The capacity of human hepatic cell-based models to predict hepatotoxicity depends on the functional performance of cells. The major limitations of human hepatocytes include the scarce availability and rapid loss of the hepatic phenotype. Hepatoma cells are readily available and easy to handle, but are metabolically poor compared with hepatocytes. Recently developed human upcyte hepatocytes offer the advantage of combining many features of primary hepatocytes with the unlimited availability of hepatoma cells. We analyzed the phenotype of upcyte hepatocytes comparatively with HepG2 cells and adult primary human hepatocytes to characterize their functional features as a differentiated hepatic …
Ribonuclease H levels in herpes simplex virus-infected cells.
1980
Two forms of ribonuclease H (RNase H) have been identified both in uninfected and Herpes Simplex virus (HSV-)infected BHK cells. Identical RNase H species were detected in control- as well as in infected cells. RNase H I and II have not been found to be associated both with host cell DNA polymerase alpha and beta and HSV-induced DNA polymerase. Infection of BHK cells with HSV type 1 does not lead to a pronounced alteration of RNase H II activity but to an increase (3-fold) of the extractable RNase H I activity. RNase H I activity increases to a maximum between 8-10 hours p.i.; the bulk of HSV-DNA synthesis occurs between 6-8 hours p.i. From these experiments we draw the preliminary conclusi…
Isolation and characterization of a chlorogenic acid esterase from Aspergillus niger.
1980
Abstract The isolation and characterization of a specific chlorogenic acid esterase is described. The enzyme activity is measured by determination of the hydrolysis product caffeic acid. The enzyme had been concentrated by means of ultrafiltration and column-chromatography. The pH- and temperature optimum were 6.5 and 45 °C respectively. Divalent cations were not required for the enzyme activity. As other esterases, this enzyme is inhibited by di-isopropyl-phosphorofluoridate. The Km-value is 0.70 mᴍ chlorogenic acid, the molecular weight 240000. The described enzyme is specific for chlorogenic acid. On the other hand a typical unspecific esterase like the pig liver esterases does not split…
Serum TRACP 5b Is a Useful Marker for Monitoring Alendronate Treatment: Comparison With Other Markers of Bone Turnover
2005
We studied clinical performance of serum TRACP 5b and other bone turnover markers, including S-CTX, U-DPD, S-PINP, S-BALP, and S-OC, for monitoring alendronate treatment. TRACP 5b had higher clinical sensitivity, area under the ROC curve, and signal-to-noise ratio than the other markers. INTRODUCTION: The purpose of this study was to compare the clinical performance of serum TRACP 5b (S-TRACP5b) with that of other markers of bone turnover in the monitoring of alendronate treatment. MATERIALS AND METHODS: This double-blinded study included 148 healthy postmenopausal women that were randomly assigned into two groups: one receiving 5 mg alendronate daily (n=75) and the other receiving placebo …
Putative role of nitric oxide synthase isoforms in the changes of nitric oxide concentration in rat brain cortex and cerebellum following sevoflurane…
2005
We have previously observed an increase in nitric oxide (NO) content in rat brain cortex following halothane, sevoflurane or isoflurane anaesthesia. This study was undertaken in order to determine whether isoform-specific nitric oxide synthase (NOS) inhibitors and inducers could modify these increases in NO contents. Rats were subjected to isoflurane and sevoflurane anaesthesia with concomitant administration of neuronal nitric oxide synthase (nNOS) inhibitor 7-Nitro-indazole (7-NI), inducible nitric oxide synthase (iNOS) inhibitor 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT) or lipopolysaccharide. NO concentration in different organs was measured by electron paramagnetic resonance (E…
Effects of a low-frequency sound wave therapy programme on functional capacity, blood circulation and bone metabolism in frail old men and women
2009
Objective: To evaluate the effects of a low-frequency sound wave therapy programme on functional capacity, blood circulation and bone metabolism of the frail elderly. Design: Single-blind, randomized, controlled trial. Setting: Two senior service centres. Subjects: Forty-nine volunteers (14 males and 35 females) aged 62—93 years with up to 12 diagnosed diseases were allocated in either the intervention group (n = 30) or control group (n = 19). Intervention: The intervention group underwent sound wave therapy, 3—5 times a week for 30 minutes per session over a period of 6 months. The control group received no intervention. Main measurements: Blood pressure, functional capacity, mobility, bo…
Toxicological implications of enzymatic control of reactive metabolites.
1990
Many foreign compounds are transformed into reactive metabolites, which may produce genotoxic effects by chemically altering critical biomolecules. Reactive metabolites are under the control of activating, inactivating and precursor sequestering enzymes. Such enzymes are under the long-term control of induction and repression, as well as the short-term control of post-translational modification and low molecular weight activators or inhibitors. In addition, the efficiency of these enzyme systems in preventing reactive metabolite-mediated toxicity is directed by their subcellular compartmentalization and isoenzymic multiplicity. Extrapolation from toxicological test systems to the human req…
Activation of the plant plasma membrane H+ -ATPase. Is there a direct interaction between lysophosphatidylcholine and the C-terminal part of the enzy…
1996
The antagonistic effects of the fungal toxin beticolin-1 and of L-alpha-lysophosphatidylcholine (lysoPC) were investigated on the plasma membrane H+-ATPase of the plant Arabidopsis thaliana (isoform 2) expressed in yeast, using both wild-type enzyme (AHA2) and C-terminal truncated enzyme (aha2delta92). Phosphohydrolytic activities of both enzymes were inhibited by beticolin-1, with very similar 50% inhibitory concentrations, indicating that the toxin action does not involve the C-terminal located autoinhibitory domain of the proton pump. Egg lysoPC, a compound that activates the H+-ATPase by a mechanism involving the C-terminal part of the protein, was found to be able to reverse the inhibi…
Synthesis and Evaluation of a Novel Series of Pyrrolizine Derivatives as Dual Cyclooxygenase-1 and 5-Lipoxygenase Inhibitors
1997
The aim of our study was to investigate structure activity relationship following the replacement of the 6-phenyl substituent at the 6,7-diaryl-2,3-dihydropyrrolizine template by various heteroaromatic residues. In this context we developed a new, efficient, and highly sensitive test method for the screening of dual cyclooxygenase-1 (COX-1) and 5-lipoxygenase (5-LOX) inhibitors. We used human platelets as a source of COX-1 and human PMNLs as a source of 5-LOX. Both cell types were isolated from the same volume of blood. PGE2 and LTB4 respectively were determined by highly selective and sensitive ELISA kits, using monoclonal antibodies. For a single determination at most 0.5 mL whole blood i…