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ABSTRACT: A precolumn derivatization-high performance liquid chromatographic method for the determination of homocysteine (Hcy) in plasma was established. Tris (2-carboxyethyl) phosphine hydrochloride (TCEP) and N-(1-pyrenyl) maleimide (NPM) were used as the reduced reagent and derivatization reagent, respectively. The separation was carried out on an Agilent Hypersil C-18 column (250 mm x 4.0 mm, 5 microm) in gradient elution mode. The mobile phase consisted of A (15 mmol/L sodium acetate solution), B (acetonitrile) and C (300 mL water containing 1 mL acetic acid and 1 mL phosphoric acid). The eluate was monitored by the fluorescence detector at an excitation wavelength of 330 nm and an emission wavelength of 380 nm. The mean recovery of Hcy was (102.08 +/- 4.94)%. The linear range was from 0.500 micromol/L to 100 micromol/L, with a detection limit of 0.016 micromol/L. The intra-day and inter-day relative standard deviations (RSDs) for Hcy were less than 5%. Seven plasma samples of patients with hypertension and seven plasma samples of healthy controls were tested, and the results demonstrated that the Hcy in the plasma from the hypertension group was significantly different from that of the control group (p < 0.05). The developed method is simple, fast, accurate, and suitable for clinical measurement.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 06/2012; 30(6):613-7.
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ABSTRACT: To investigate the frequency and type of both chromosomal abnormalities and Y chromosome microdeletions and analyze their association with defective spermatogenesis in Chinese infertile men.
This is a single center study. Karyotyping using G-banding and screening for Y chromosome microdeletion by multiplex polymerase chain reaction(PCR)were performed in 200 controls and 1,333 infertile men, including 945 patients with non-obstructive azoospermia and 388 patients with severe oligozoospermia.
Out of 1,333 infertile patients, 154(11.55%) presented chromosomal abnormalities. Of these, 139 of 945 (14.71%) were from the azoospermic and 15 of 388 (3.87%) from the severe oligozoospermic patient groups. The incidence of sex chromosomal abnormalities in men with azoospermia was 11.53% compared with 1.03% in men with severe oligozoospermia (P < 0.01). Also 144 of 1,333(10.80%) patients presented Y chromosome microdeletions. The incidence of azoospermia factor(AZF) microdeletion was 11.75% and 8.51% in patients with azoospermia and severe oligozoospermia respectively. Deletion of AZFc was the most common and deletions in AZFa or AZFab or AZFabc were found in azoospermic men. In addition, 34 patients had chromosomal abnormalities among the 144 patients with Y chromosome microdeletions. No chromosomal abnormality and microdeletion in AZF region were detected in controls.
There was a high incidence (19.80%) of chromosomal abnormalities and Y chromosomal microdeletions in Chinese infertile males with azoospermia or severe oligozoospermia. These findings strongly suggest that genetic screening should be advised to infertile men before starting assisted reproductive treatments.
Journal of Assisted Reproduction and Genetics 03/2012; 29(6):521-7. · 1.84 Impact Factor
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Min Ding,
Feng He,
Thomas W Hudyma,
Xiaofan Zheng,
Michael A Poss,
John F Kadow,
Brett R Beno,
Karen L Rigat,
Ying-Kai Wang,
Robert A Fridell,
Julie A Lemm,
Dike Qiu,
Mengping Liu,
Stacey Voss,
Lenore A Pelosi,
Susan B Roberts,
Min Gao,
Jay Knipe,
Robert G Gentles
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ABSTRACT: Presented here are initial structure-activity relationship (SAR) studies on a series of novel heteroaryl fused tetracyclic indole-based inhibitors of the hepatitis C viral polymerase, NS5B. The introduction of alternative heterocyclic moieties into the indolo-fused inhibitor class significantly expands the reported SAR and resulted in the identification of pyridino analogs, typified by compounds 44 and 45 that displayed excellent potency against the NS5B polymerase of both HCV 1a and HCV 1b genotypes.
Bioorganic & medicinal chemistry letters 03/2012; 22(8):2866-71. · 2.65 Impact Factor
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ABSTRACT: A high performance liquid chromatographic (HPLC) method with programmed wavelength ultraviolet (UV) detection was established to simultaneously determine tryptophan (Trp) and its key metabolites kynurenine (Kyn) and 5-hydroxytryptamine (5-HT). A BDS-Hypersil-C8 column (150 mm x 4.6 mm, 5 microm) was used for the analysis at 25 degrees C. The separation was carried out with the mobile phase consisting of 10 mmol/L sodium acetate-acetic acid (pH 4. 5) and acetonitrile (94: 6, v/v) using theophylline as internal standard (IS) at a flow rate of 0.6 mL/min. The eluates were monitored by the programmed wavelength UV detection at 360 nm for Kyn and IS, 220 nm for 5-HT and 302 nm for Trp. The mean recoveries were in the range of 87% to 113%. The linearities were from 3.97 to 400 micromol/L for Trp, 0.421 to 20.2 micromol/L for Kyn and 4.36 to 980.5 nmol/L for 5-HT. The detection limits were 0.134 micromol/L for Trp, 0.016 micromol/L for Kyn and 2.03 nmol/L for 5-HT. Fifteen plasma samples of patients with depression and fifteen plasma samples of healthy controls were tested, and the results demonstrated that the metabolism of Trp in the plasma from the depression group was significantly different from that of the control group.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 05/2011; 29(5):435-8.
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ABSTRACT: To develop a reliable HPLC method for the simultaneous determination of plasma tryptophan, kynurenine and 5-hydroxytryptamine to analyze tryptophan metabolism.
Separation was carried out on a C8 column with the mobile phase composed of acetate buffer (pH 4.5) and acetonitrile using theophylline as internal standard. The eluates were monitored by ultraviolet detection with programmed wavelength.
Analysis was achieved in less than 8.0min. The limits of quantification were 3.97μmol/L, 4.36nmol/L and 0.421μmol/L for tryptophan, 5-hydroxytryptamine and kynurenine, respectively. Reproducibility and recovery were satisfactory. Twenty healthy adults and 20 uremic patients undergoing hemodialysis were analyzed using the present method. Tryptophan metabolism was found to be disturbed in uremic patients and was improved obviously after hemodialysis.
The developed HPLC method is simple, reliable and suitable for monitoring tryptophan metabolism in uremic patients undergoing hemodialysis.
Clinical biochemistry 02/2011; 44(2-3):226-30. · 2.02 Impact Factor
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ABSTRACT: We here report a rapid, sensitive, selective and label-free fluorescence detection method for cysteine (Cys). The conformation of mercury-specific DNA (MSD) changes from a random coil form to a hairpin structure in the presence of Hg2+ due to the formation of a thymine-Hg2+ -thymine (T-Hg2+ -T) complex. Cys can selectively coordinate with Hg2+ and extract it from the thymine-Hg2+ -thymine complex. The hairpin structure dehybridizes and the fluorescence intensity of Sybr Green I (SG) decreases upon addition of Cys because SG efficiently discriminates mercury-specific DNA and mercury-specific DNA/Hg2+ complex. The detection can be finished within 5 min with high sensitivity and selectivity. In addition, we can obtain variable dynamic ranges for Cys by changing the concentration of MSD/Hg2+.
Sensors 01/2011; 11(11):10187-96. · 1.74 Impact Factor
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ABSTRACT: In order to understand the tryptophan catabolism in acute and chronic hepatitis B patients, we quantitatively analyzed plasma kynurenine and tryptophan simultaneously by high performance liquid chromatography with programmed wavelength ultraviolet detection.
A new and specific high performance liquid chromatography method to simultaneously measure plasma kynurenine and tryptophan with programmed wavelength ultraviolet detection using 3-nitro-tyrosine as internal standard was elaborated. Thirty patients were recruited (10 patients with acute HBV, 10 with chronic HBV and 10 healthy subjects).
The retention times of kynurenine and tryptophan were 2.9 min and 4.4 min, respectively. For kynurenine, the assay was linear from 0.442 micromol/l to 18.3 micromol/l. For tryptophan, the linearity was from 3.67 to 470 micromol/l. The detection limits were 0.014 micromol/l for Kyn and 0.122 micromol/l for Trp, respectively. Its precision and recovery are satisfactory. In this study we found that the kynurenine per tryptophan ratio of acute group is higher than control group and chronic group.
The method is simple, fast, accurate, and suitable for applicability to clinical measurement.
Clinica chimica acta; international journal of clinical chemistry 05/2009; 405(1-2):94-6. · 2.54 Impact Factor
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ABSTRACT: A simple, fast, sensitive and specific high-performance liquid chromatography (HPLC) method is developed for simultaneous determination of kynurenine (Kyn) and tryptophan (Trp) with ultraviolet (UV) detection setting programmed wavelength. The separation was carried out on an Agilent Hypersil ODS column (125 mm x 4.0 mm, 5 microm) in less than 6 min and the eluate was monitored by the programmed wavelength detection setting at 360 nm from 0 min to 4 min for Kyn, and at 278 nm from 4 min to 6 min for Trp in a single run with UV detector. The linearities of the method were from 0.20 micromol/L to 21.2 micromol/L for Kyn and 2.25-678.0 micromol/L for Trp, and the detection limits were 0.028 micromol/L for Kyn and 0.053 micromol/L for Trp, respectively. Satisfactory precisions and recoveries were obtained by this method. The assay was employed to analyze plasma samples of children patients with Kawasaki disease (KD). The result showed great difference between Kawasaki disease and control group.
Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 05/2009; 877(16-17):1678-82. · 2.78 Impact Factor
