Abstract：
BACKGROUND:Astilbin is a flavonoid isolated from the rhizome of Smilax glabra. In a previous study, we revealed its unique immunosuppressive activity, a selective inhibition against activated T lymphocytes. This characteristic of astilbin is beneficial for the treatment of human immune diseases. METHODS:We incubated astilbin with rat liver microsomal/cytosolic fractions and isolated the metabolite of astilbin, which was fully characterized by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy. We administered astilbin orally via a gastric tube to rats at 0.22 mmol/kg and collected whole blood samples after 30 min and urine samples after 0 to 12 h. We applied HPLC and liquid chromatography/MS to measure the metabolite in the samples, and we assayed cytokine expression by reverse-transcription PCR. RESULTS:After incubation of astilbin with rat liver microsomal/cytosolic fractions, we detected a new metabolite of astilbin and isolated it from the culture solution. We characterized this metabolite by MS and NMR techniques as 3'-O-methylated astilbin. We detected the metabolite in both blood and urine samples after oral administration of astilbin, and the metabolite inhibited picryl chloride-induced ear swelling in mice and suppressed the expression of tumor necrosis factor-alpha and interferon-gamma, similarly to astilbin. CONCLUSION:This is the first identification of 3'-O-methylastilbin as a new flavonoid, as well as an active metabolite of astilbin in vivo, and is helpful for studying the kinetics of astilbin and its clinical applications.
journal_name
Clin Chemjournal_title
Clinical chemistryauthors
Guo J,Qian F,Li J,Xu Q,Chen Tdoi
10.1373/clinchem.2006.077297subject
Has Abstractpub_date
2007-03-01 00:00:00pages
465-71issue
3eissn
0009-9147issn
1530-8561pii
clinchem.2006.077297journal_volume
53pub_type
杂志文章abstract：BACKGROUND:Little is known about lipoprotein(a) [Lp(a)] as a predictor of vascular events among ethnic Chinese. We prospectively investigated the association of Lp(a) with cardiovascular disease and all-cause death in a community-based cohort. METHODS:We conducted a community-based prospective cohort study of 3484 par...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2007.090969
更新日期：2008-02-01 00:00:00
abstract：:Changes in values for myoglobin, total creatine kinase (EC 2.7.3.2), and creatine kinase B-subunit in the serum of patients with thyroid disease are compared with values for these during the 24-h after myocardial infarction. Concentrations of all three of these muscle-derived proteins were significantly higher than no...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-01-01 00:00:00
abstract：:Determination of the concentration of erythrocyte folate by means of competitive protein binding assay critically depends on the extraction procedure applied. Results will be influenced by variable factors such as the in vitro age of the blood samples, the degree of hemolysis, the presence of ascorbic acid, and the pH...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1976-07-01 00:00:00
abstract：BACKGROUND:Patients with trophoblastic diseases produce ordinary and irregular forms of human chorionic gonadotropin (hCG; e.g., nicked hCG, hCG missing the beta-subunit C-terminal segment, hyperglycosylated hCG, and free beta subunit) that are recognized to differing extents by automated immunometric hCG (or hCG beta)...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2001-02-01 00:00:00
abstract：:The IFCC-recommended procedure for aspartate aminotransferase (EC 2.6.1.1) was adapted to the centrifugal analyzer and evaluated during five years. The main hindrance to widespread use of the recommended method is the need for pre-incubation with pyridoxal phosphate. The present method includes a 10-min pre-incubation...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1981-01-01 00:00:00
abstract：:We measured the concentration of carboxyhemoglobin (HbCO) in blood samples from 32 neonates by spectrophotometry (IL282 CO-Oximeter) and gas chromatography, finding a strong positive correlation (r = 0.89) between the concentration of fetal hemoglobin (Hb F) and HbCO as measured by spectrophotometry, but not by gas ch...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-05-01 00:00:00
abstract：:Since 1991, the Ontario Laboratory Proficiency Testing Program has assessed the analytical performance of creatine kinase (CK; EC 2.7.3.2) isoenzyme-2, using fresh human serum supplemented with purified human CK isoenzymes. In Ontario, the 142 laboratories licensed to analyze CK-2 use a variety of methods: electrophor...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1994-02-01 00:00:00
abstract：BACKGROUND:Cyclosporin A (CsA) is commonly measured by immunoassay techniques that have a limited analytical range. The consequence of this is that low CsA concentrations that may be clinically significant are difficult to measure and that high concentrations require sample dilution, which introduces error and increase...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2002-01-01 00:00:00
abstract：:Intra-erythrocytic pH, ATP concentrations, and 2,3-diphosphoglycerate relaxation times were studied in living erythrocytes by "high-resolution" 31P NMR spectroscopy to assess homeostasis within the cells. In uremic patients, intra-erythrocytic pH is significantly decreased before hemodialysis, but is corrected equally...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1987-01-01 00:00:00
abstract：:We describe a radioassay for cobalamin (vitamin B12) in human serum or plasma that requires no boiling or other pretreatment of the sample. Normal chicken serum covalently coupled to magnetizable particles is used as the binding agent. The assay is performed at pH 12.9, at which pH all cobalamin in human serum is rele...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1981-02-01 00:00:00
abstract：:We describe the development of a stable reference material for prostatic acid phosphatase, derived from human prostatic tissue and human seminal fluid. The enzyme was purified by an L-tartramic acid affinity-chromatography technique. Two-dimensional electrophoresis revealed essentially no contaminating proteins, and s...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-08-01 00:00:00
abstract：:In this fluorometric assay for phospholipase A2 (EC 3.1.1.4) in serum we use the fluorescent phospholipid analog 1-octacosanyl-2-(pyren-1-yl)hexanoyl-sn-glycero-3-phosphatid yl monomethyl ester as substrate. The optimized conditions are: 28 mumol of the substrate per liter of Tris buffer (20 mmol/L, pH 7.4). The hydro...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1985-05-01 00:00:00
abstract：:We evaluated a new, simple, enzymatic kinetic method from Wako Chemicals GmbH in comparison with a kinetic Jaffé method by using isotope dilution-mass spectrometry (ID-MS) as a reference method. An ID-MS-calibrated serum standard was used. Both the enzymatic and the Jaffé method correlated well with ID-MS, except for ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1989-05-01 00:00:00
abstract：BACKGROUND:Because cyclosporin A (CsA) and glucocorticoids inhibit the production of interleukin-2 (IL-2) and other cytokines, quantitative analysis of cytokine mRNA might constitute a pharmacodynamic measure for immunosuppressive drug effects. We investigated whether immunosuppressive drugs influence cytokine mRNA exp...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2002-12-01 00:00:00
abstract：BACKGROUND:Coffee consumption has been associated with several risk factors for coronary heart disease, including increased cholesterol, increased blood pressure, and increased plasma total homocysteine (tHcy). tHcy is determined by several B-vitamins. However, reports about the association between coffee intake and B-...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2008.103465
更新日期：2008-09-01 00:00:00
abstract：BACKGROUND:Paraoxonase may protect lipoproteins and cell membranes from peroxidation, and alterations in the activity of this enzyme have been associated with some chronic diseases. Serum paraoxonase appears to be mainly under genetic control, but some studies suggest that environmental factors may also modulate its ac...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/49.9.1491
更新日期：2003-09-01 00:00:00
abstract：BACKGROUND:The current diagnosis and monitoring of bladder cancer are heavily reliant on cystoscopy, an invasive and costly procedure. Previous efforts in urine-based detection of bladder cancer focused on targeted approaches that are predicated on the tumor expressing specific aberrations. We aimed to noninvasively de...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1373/clinchem.2018.301341
更新日期：2019-07-01 00:00:00
abstract：:We compared five ion-selective electrodes (ISEs; AVL 985S, Baxter Lytening 2Z, Beckman EL-ISE, Ciba-Corning 654 Na/K/Li, and Nova CRT 11) and a colorimetric method (Ektachem) for determination of lithium with flame atomic absorption and atomic emission spectroscopy. We evaluated precision, recovery, interference by dr...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1994-06-01 00:00:00
abstract：:Immunoradiometric analysis has made it possible to measure ferritin reliably in serum. The determination is a sensitive means of assessing body iron because concentrations of ferritin closely parallel the body's reticuloendothelial iron stores. The information provided is similar to that obtained from bone-marrow aspi...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1980-01-01 00:00:00
abstract：:We coupled a kinetic procedure to a selective inhibiting method for determining amylase isoenzymes in biological samples, using 4-nitrophenylmaltopentaoside plus 4-nitrophenylmaltohexaoside as substrate and a wheat-germ selective inhibitor with the Gilford S-III spectrophotometer. On plotting remaining amylase activit...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-08-01 00:00:00
abstract：:We report the kinetics of the reactions of unconjugated bilirubin and conjugated bilirubin with p-diazobenzene sulfonic acid in aqueous media. Our studies confirm that each reaction proceeds in two steps and that the second step is catalyzed by sulfanilic acid. In the presence of an excess of p-diazobenzenesulfonic ac...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1978-10-01 00:00:00
abstract：:The commonly used methods of assessing the precision of the automated leukocyte differential have certain drawbacks that affect the validity and comparability of results. In the present report, we introduce a procedure based on building precision profiles from a large number of within-run imprecision experiments. The ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1996-07-01 00:00:00
abstract：:We have developed a succinyldicholine-based assay for serum cholinesterase (EC 3.1.1.8) to help establish whether patients with suspected sensitivity to drugs of this type have enzyme abnormalities that cannot be detected by conventional laboratory techniques. Although the method discriminates between cholinesterase a...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1986-08-01 00:00:00
abstract：:Human myocardial creatine kinase isoenzyme MM is present as a single form in tissue, but upon its release into plasma two additional forms, with faster anodal migration, are apparent on polyacrylamide electrophoresis. We designate the three forms as MM3, MM2, and MM1 in increasing order of anodal mobility. When tissue...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1984-05-01 00:00:00
abstract：:We describe a ratio gas-chromatographic method for determination of cortisol production rate by measuring the isotope dilution of urinary cortisol metabolites. The method was calibrated by analyzing [3H]tetrahydrocortisol and [3H]tetrahydrocortisone of known specific activities. Results are reasonably well reproducibl...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1977-03-01 00:00:00
abstract：BACKGROUND:Atherosclerosis is a systemic disease with focal rupture of vulnerable plaque responsible for major clinical events. Several population-based studies indicate an association between lipoprotein-associated phospholipase A2 (Lp-PLA2) and cardiovascular events. Lp-PLA2 is emerging as a biomarker that may be a p...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：10.1373/clinchem.2006.070672
更新日期：2006-09-01 00:00:00
abstract：:A modified agarose electrophoretic system for the separation of alkaline phosphatase (ALP, EC 3.1.3.1) isoenzymes is described. Bone, liver, high-molecular-mass, and intestinal ALP are separated with high reproducibility. The sensitivity of the agarose system is superior to cellulose acetate in detecting high-Mr ALP. ...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：1988-09-01 00:00:00
abstract：BACKGROUND:The analysis of red cell folate (RCF) depends on complete hemolysis of erythrocytes, and it is assumed that complete hemolysis is achieved by 10-fold dilution of whole blood with hypotonic solutions of 10 g/L ascorbic acid/ascorbate. This report challenges this assumption. METHODS:The conventional method of...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：
更新日期：2000-12-01 00:00:00
abstract：BACKGROUND:An accelerated stability model based on the Arrhenius Equation can be used to estimate stability of diagnostic reagents. Here we review 3 examples in which the model does not accurately predict the stability of diagnostic reagents. METHODS:We prepared several pilot lots of quality controls materials contain...
journal_title：Clinical chemistry
pub_type： 杂志文章
doi：10.1093/clinchem/hvaa282
更新日期：2020-12-04 00:00:00
abstract：:Major discoveries have been made in the past few years on the structure and mode of biosynthesis of serum albumin. The complete amino acid sequence of this protein has been determined, and its covalent structure shown to be a single peptide chain grouped into a series of nine disulfide-bonded loops. These loops appear...
journal_title：Clinical chemistry
pub_type： 杂志文章,评审
doi：
更新日期：1977-01-01 00:00:00
