Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0040822 (tremor)
 18,428 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A convenient method was developed for determination of sulfathiazole (STZ) in Type C medicated swine feed by reversed-phase liquid chromatography (LC) with post-column derivatization. Addition of extractant solution (0.2N HCl and 1.5% diethylamine in 25% methanol) and an internal standard (IS), sulfamethylthiazole (SMZ), to 5 g sample was followed by mechanical shaking for 1 h. The extract was clarified by chilling, centrifugation, and filtering before injection onto a C18 reversed-phase column. The mobile phase components were 2% acetic acid and 1:1 acetonitrile-methanol (83 + 17%, v/v). Run time was about 20 min. Determination and, largely, the method's selectivity were based on detection at 450 nm of the derivative formed by the post-column reaction of dimethylaminobenzaldehyde with the primary amine of the analyte and IS. The IS, SMZ, differs from STZ by a single substituent methyl group, is stable, and is readily resolved from STZ. Although SMZ is not commercially available, it can be synthesized with relative ease from purchased reagents and will be supplied by the authors to interested laboratories. In single-laboratory validation, linearity was demonstrated over the range of 0.055-550 microg/mL, well beyond the target concentration of 5.5 microg/mL. The estimated limit of detection was 0.04 microg/mL; the calculated limit of quantitation was 0.13 microg/mL (feed concentration of 2.4 g/T or 2.7 mg/kg). Wet-spiking trials with a variety of swine feed matrixes showed recovery to be 100-102% for the intended concentration range, 50-200 g/T, with coefficient of variation (CV) < 2%. The method ruggedness was verified with an overall CV of 2.9%.
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PMID:Determination of sulfathiazole in type C medicated swine feed by reversed-phase liquid chromatography with post-column derivatization. 1450 17

A simple, very efficient method is presented for routine analysis of herbicide Krovar I (active components bromacil and diuron) in water and soil samples. Water samples were extracted by liquid-liquid extraction with dichloromethane (DCM) as extraction solvent. For soil samples two different extraction techniques were compared: microwave-assisted solvent extraction and a shaking technique using a platform shaker. Extracts were analyzed by high performance liquid chromatography using a water:methanol gradient. Liquid chromatography was coupled with atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) for quantification of bromacil and diuron. Optimization of the APCI-MS was done by using standards in the flow injection analysis mode (FIA). Method detection limit for liquid samples for bromacil is 0.04 microg L(-1) and for diuron 0.03 microg L(-1). Method detection limit for soil samples is 0.01 microg g(-1) dry weight for both compounds. Results of analysis of field samples of water and soil are also presented.
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PMID:Analysis of herbicide Krovar I by liquid chromatography with atmospheric pressure chemical ionization mass spectrometry. 1513 32

The performance of a commercially available microtiter plate ELISA kit for the determination of the neonicotinoid insecticide imidacloprid was evaluated for sensitivity, selectivity, influence of organic solvent used for extraction procedure, matrix interference originated from agricultural sample, accuracy, and method comparison with conventional HPLC analysis. The limit of detection for the kit (0.1 or 0.5 ng/mL) was determined. The working range (1-39 ng/mL) experimentally calculated on the basis of a criterion, which is determined as the range from I(20) to I(80), was comparable to that established by the manufacturer (1-50 ng/mL). The linearity of the standard curve based on the kit-assembled standard solutions agreed with the one based on the self-made standard solutions. Specificity studies indicate that the imidacloprid monoclonal antibody can readily distinguish the target compound from other structurally related neonicotinoid analogues and some metabolites, with the exception of clothianidin, the cross-reactivity of which was approximately 12%. To extract imidacloprid from an agricultural sample (apple) as simply and rapidly as possible, some extraction methods were examined. Consequently, the extraction method with hand-shaking for 5 min was the best among the examined methods. For the analysis of imidacloprid in apple samples, it was extracted directly with methanol and the extracts were diluted 10-fold (100-fold in the well) with water prior to ELISA analysis. No significant matrix interference was observed with the dilution factor. Recoveries of imidacloprid from fortified apple samples ranged from 87.7 to 112.0%. The results obtained with the ELISA kit correlated well with those by the reference method (conventional HPLC analysis) for apple samples (r > 0.998). These findings strongly indicate that the ELISA kit may be employed routinely for an on-site imidacloprid residue analysis of apple samples.
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PMID:Evaluation and validation of a commercially available enzyme-linked immunosorbent assay for the neonicotinoid insecticide imidacloprid in agricultural samples. 1513 10

A simple and cost-effective method using thin-layer chromatography for the determination of the mycotoxin fumonisin B1 in maize is described. The analytical method consisted of the extraction of ground maize by shaking with methanol/water (75:25) for 60 min and clean-up of the resultant extract by means of strong anion exchange solid-phase extraction. The purified residue, formed by evaporation of the elution solvent, was reacted with fluorescamine and the fumonisin B1-derivative was separated by reversed-phase thin-layer chromatography using a developing solution of methanol/aqueous 4% potassium chloride (70:30). The derivatized FB1 was readily visualized as a greenish-yellow spot under long wavelength ultraviolet light and quantified by visual comparison with a set of similarly derivatized standards in the range 20-300 ng FB1 spotted on plate. Based on visual comparison, levels down to 0.5 mg kg(-1) were successfully estimated. The method was collaboratively studied in 14 laboratories using four duplicate maize meal samples (including a blank) and a spiked sample for determination of recovery. No significant difference was observed between mean FB1 levels by high-performance liquid chromatography or thin-layer chromatography. Based on within-laboratory relative standard deviations of 27.1-41.7% and between-laboratory relative standard deviations of 35.0-63.3%, the method can be considered semiquantitative. The mean recovery achieved by participants at a spiking level of 2.00 mg kg(-1) was 74.5%.
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PMID:Determination of the mycotoxin fumonisin B1 in maize by reversed-phase thin-layer chromatography: a collaborative study. 1520 51

Liquid chromatography (LC) with diode array ultraviolet absorbance (DAD UV) detection is used for the simultaneous determination of the fungicide maneb and its main metabolites (ethylenethiourea--ETU, ethylenebis (isothiocyanate) sulfide--EBIS, and ethyleneurea--EU) in tomatoes. The identity of EBIS, one of the main UV degradation products of maneb, was verified by both DAD UV detection and mass spectrometry. The analytes were extracted three times with 3 mL of 1:1:1 acetonitrile-dichloromethane-chloroform by 2 min of mechanical shaking and separated on a C-18 column by gradient elution with an acetonitrile-methanol-aqueous 100mM sodium dodecylsulfate (SDS) mixture. The quantification limits of 0.45, 0.04, and 0.35 mg kg(-1) obtained for maneb, ETU, and EU, respectively, show that the proposed method is suitable for their determination in tomatoes.
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PMID:Simultaneous determination of maneb and its main metabolites in tomatoes by liquid chromatography using diode array ultraviolet absorbance detection. 1533 96

Preparations from comfrey (Symphytum officinale and S. x uplandicum) root and leaf contain varying levels of the hepatotoxic pyrrolizidine alkaloids (PAs). Reference compounds for comfrey are not commercially available, and there is currently no rapid extraction or analytical method capable of determining low levels in raw materials or as adulterants in commercially available extracts. A solid-phase extraction (SPE) method was developed using an Ergosil cleanup column that specifically binds the PAs. With this method, powdered comfrey root was extracted by sonication and shaking with basic chloroform. The extract was applied to the cleanup column under vacuum, washed with 2 mL acetone-chloroform (8 + 2, v/v) followed by 2 mL petroleum ether to remove excess chloroform. The column was dried under vacuum, and the PAs were eluted with 2 successive 1 mL aliquots methanol. Percent recoveries of the PAs following Ergosil SPE had an overall average of 96.8%, with RSD of 3.8% over a range of 1.0 to 25.0 g extracted in 100 mL. Average precision of the method (n = 3 over 4 extraction concentrations) gave an overall RSD of 6.0% for the 5 alkaloids, with a range of 0.8% (5 g in 100 mL) to 11.2% (25 g in 100 mL). Recovery optimization testing showed that 1.0 g comfrey root extracted in 100 mL yielded the greatest recovery (% dry weight) of the PAs, with an extraction efficiency and accuracy of 94.2%, and RSD of 1.7% (n = 9). The unique properties of the Ergosil cleanup column provide rapid sample cleanup, volume reduction, and concentration of PAs from comfrey extracts, and allow the eluant to be analyzed directly by traditional chromatographic methods.
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PMID:A rapid cleanup method for the isolation and concentration of pyrrolizidine alkaloids in comfrey root. 1549 60

The cDNA of N-terminal extracellular domain of human leukemia inhibitory factor receptor a-subunit (gp190) ,which encoded soluble gp190 (sgp190) ,was cloned into the methylotrophic yeast Pichia pastoris secreted expression vector pPIC9K. The linearized plasmid sgp190-pPIC9K was then integrated with GS115 genome by spheroplasts transformation. MD medium and PCR method were used for screening positive transformants. The transformants (His+ Mut+) containing multi-copy gene insertion were selected with increasing concentration of antibiotic G418 and induced by 0.5% methanol in shaking flask to express sgp190. The sgp190 expressed level could reach up to 26% of total proteins in culture supernatant. SDS-PAGE and Western blotting analysis showed that the molecular weight of sgp190 is about 125 kD and could be specifically recognized by polyclonal antibodies against human sgp190,which indicated good antigenicity of this secreted expressed protein. Biological activity assay showed that purified sgp190 could inhibit the effect of LIF on hCG biosynthesis of cytotrophoblast in vitro.
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PMID:Expression of human soluble gp190 in yeast Pichia pastoris. 1565 68

A simple but very effective sample preparation method is discussed for a matrix or drug-in-adhesive type of transdermal drug delivery system (TDS). The method is a one-step extraction using a methanol/water solvent system. Because of the unique design and physical property of the delivery system, special considerations were taken in selection of sample solvent, sample container and extraction enhancement device. The main focus of the article is on method optimization using experimental designs. A Plackett-Burman design was used to screen multiple method factors including extraction solvent strength, extraction solvent volume, shaking speed of a reciprocating shaker, and shaking time. Later, two of the factors were studied in more details using a 4 x 5 general factorial design. From the experimental results, the so-called main effects plots and interaction plots were generated using a statistical software. The plots are helpful in choosing the method conditions.
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PMID:Sample preparation optimization for assay of active pharmaceutical ingredients in a transdermal drug delivery system using experimental designs. 1574 Sep 9

The capsid protein (VP60) gene of RHDV was subcloned into the Pichia expressin vector pPICZ B to express the VP60 protein intracellularly. The recombinant plasmid was initially transformed into a E. coli strain TOP10 F'. After verification of the construct by sequencing, the recombinant plasmid was linearized by Sac I in the 5' AOX1 region and then transformed into Pichia pastoris strain GS115 using the Pichia EasyComp Kit. After selecting and verifing for the insertion of VP60 gene in the genome, two clones of Pichia transformants were select for expression test. The recombinant clones were first inoculate with BMGY in baffled flask at 28-30 degrees C in a shaking incubator (250-300 r/min) until culture reaches an OD600 = 2-6, then resuspend the cell pellet to an OD6oo of 1.0 in BMMY medium to induce expression for 5 days by methanol at a concentration of 0.5% in a 1 liter baffled flask covered with 2 layers of sterile gauze. Collect the cell pellets and break it by acid-washed 0.5 mm glass beads. The expression of recombinant Pichia strains was detected by SDS-PAGE and Western analysis with a polyclonal serum which showed a specific protein band of 60kD. Theses results indicates that the recombinant VP60 produced in Pichia was antigenically similar to the viral polypeptide. Electron microscopic observation of the recombinant Pichia-derived protein revealed the presence of virus-like particles similar in size and appearance to native virus capsids. In the haemagglutination test, the recombinant VLPs, like the native RHDV, also agglutinated human blood type O erythrocytes and could be inhibited by the anti-RHDV polyclonal serum.
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PMID:[Expression of capsid gene of Chinese isolate of rabbit hemorrhagic disease virus in Pichia pastoris]. 1585 43

Tetracaine hydrochloride (TH) is nominated as the prohibited ingredients in cosmetics in Japanese Pharmaceutical Affairs Act. So the analytical method for TH was investigated by HPLC. After adding 5 ml of TH solution at 10 microg/ml and 2 ml of salicylic acid solution at 75 microg/ml as the internal standard to 0.5 g of the lotion, the mixture was made up to 10 ml with a mixture of water and methanol (1:1) as the testing solution. Milky lotion was procedured as follows: After adding 5 ml of TH solution at 10 microg/ml and 2 ml of internal standard solution to 0.5 g of the milky lotion, the mixture was made up to 10 ml with a mixture of water and methanol (1:1). Two milliliter of this mixture was placed into a centrifuging tube with a cap and 2 ml of hexane was added. After shaking vigorously and centrifuging, the lower layer was used as the testing solution. In the case of the cream, the other procedures were used: 0.5 g of cream was placed into a 10-ml volumetric flask and 1 ml of tetrahydrofuran was added. After dissolving, the mixture of methanol and water (1:1) was added to make up 10.0 ml. Two milliliter of this mixture was placed into a centrifuging tube with a cap and 2.0 ml of hexane was added. After shaking vigorously and centrifuging, the lower layer was used as the testing solution. The testing solution of 20 microl was analyzed by HPLC using the ODS column (CAPCELL PAK C18 column, 4.6 x 250 mm), the mixture of acetonitrile and 50 mmol/l phosphate buffer(pH 2.0)(7:3) and the detection wavelength of 303 nm. The working curves from 0.5 to 6.0 microg/ml showed a linear line between the concentrations of TH and the peak area ratio. There was no interference of peak of TH from the lotion, milky lotion and cream.
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PMID:[Studies for analyzing prohibited ingredients such as tetracaine hydrochloride in cosmetics]. 1594 Sep


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