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)

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

Vitamin A acid (VAA) was firstly dissolved in chloroform, and then the organic solution containing the samples was mixed with silver sol at the desired concentration. After sufficient shaking, collect SERS spectra of VAA with silver sol layer solution. The attribution of the peaks was illustrated by comparing SERS spectra with NR (Normal Raman) spectra, and the mechanism and orientation of adsorption were also discussed according to the peaks which was absent in NR spectrum but observed in SERS spectrum. To verify the feasibility of the method for the quantitative analysis, SER spectra at different concentration of VAA were collected. The intensities measured with the band at 1583 cm(-1) were plotted as a function of concentration. It was found that an effective limit for the detection of VAA could be as low as to 1.0 x 10(-7) mol x L(-1), the calibration curve was linear in the range from 1.0 x 10(-6)-5 x 10(-5) mol x L(-1). The proposed method has the potential to quantitative assay of the drugs having SERS effects but undissolvable in water.
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PMID:[SERS spectra of vitamin A acid in silver solution]. 1576 81

Two compounds showing self-inhibitory action during germination of aeciospores of the comandra blister rust fungus (Cronartium comandrae Pk.) were extracted from these aeciospores by shaking with 0.2 M NH(4)HCO(3) (pH 7.8) for 4 h. One of these, the germination self inhibitor (D. A. Eppstein and F. H. Tainter, Phytopathology 66:1395-1397, 1976), was removed from the ammonium bicarbonate buffer by using chloroform. The water layer which remained contained a substance which, at ca. 10 M concentration, had no apparent effect on germ tube emergence but which inhibited normal germ tube growth. Linear germ tube growth ceased or a dendritic or vesicular pattern of growth resulted, depending on the concentration of inhibitor added to extracted germinating spores. The germ tube growth inhibitor appears to be a peptide with a molecular weight of ca. 2,000.
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PMID:Germ Tube Growth Inhibitor from Cronartium comandrae Aeciospores. 1634 35

A protocol for direct extraction of mRNA from soil samples was developed. Soil samples (10 g) were washed twice with 120 mM phosphate buffer (pH 5.2). The lysis of cells, fixation of RNA, and hydrolysis of DNA were achieved by vigorously shaking the washed soil in a 4 M guanidine thiocyanate solution containing 25 mM sodium citrate, 0.5% sarcosyl, and 0.1 M 2-mercaptoethanol. The pH of the homogenized mixture was adjusted with 2 M sodium acetate (pH 4.0); the mRNA was then extracted with phenol and chloroform. Total RNA was precipitated with isopropanol. This method extracts up to 17 mug of total RNA per g (wet weight) of soil containing 8.0 x 10 cells of Pseudomonas aeruginosa PU21, and mRNA has been detected in 160-ng total RNA fractions. This method has been used for the detection of mRNA transcribed from specific biodegradative genes, including the nah and mer operons, in contaminated soils. This extraction method can be completed within a few hours and has tremendous potential for ecological studies of in situ gene expression among soil microbiotas.
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PMID:Rapid method for direct extraction of mRNA from seeded soils. 1634 41

The high-performance liquid chromatography with electrochemical detection (HPLC-EC) of six anthracycline antibiotics is described. All the compounds of interest may be analysed using a reversed-phase column (ODS Hypersil or Zorbax ODS) and a mobile phase consisting of acetonitrile-isopropanol-0.1 M phosphate buffer (pH 4.5). The use of short columns (7.5 cm) allowed short analysis times and improved sensitivity, such that detection limits of between 1 and 2 ng ml(-1) could be achieved. Sample preparation involved an alkaline extraction into chloroform, followed by a back extraction into acid solution. Final clean-up of the samples is achieved by shaking the final acidic extract with an organic solvent. The precision of the assay for the compounds studied ranges between 1.22 and 6.46% and the accuracy ranges between 94.5 and 106.0%. The analytical methodology developed is applied to the clinical pharmacokinetics of 4'-deoxydoxorubicin. The correlation between plasma levels found by HPLC-EC and those found by HPLC with fluorescence detection is excellent (r(2) = 0.990).
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PMID:High-performance liquid chromatography of anthracycline antibiotics with electrochemical detection. Application to the clinical pharmacokinetics of 4'-deoxydoxorubicin. 1686 44

Solvent extraction is a very powerful purification step in the preparation of VAQTA, a highly purified, inactivated hepatitis A vaccine. Extraction of an aqueous product-containing protein solution with chloroform through vigorous shaking causes irreversible denaturation of contaminant proteins at the interface. However, the hepatitis A virus (HAV) remains viable and soluble in the aqueous phase. Because three phases (air, aqueous, and organic) are involved, and the mixing is carried out in individual bottles, there is very little theory available to characterize this process, so it must be studied experimentally. This extraction step was characterized by following the removal of a specific impurity from the aqueous phase as a representative marker for the degree of protein precipitation. These experiments led to the identification and optimization of the important variables controlling the extraction step. They were found to be mixing time and size of vessel, with longer mixing times resulting in higher purity and larger bottle size leading to faster kinetics of impurity removal. These parameters are most likely related to solvent/aqueous interfacial area and the resulting shear due to shaking. We conclude that, to scale up this type of mixing, the kinetics of impurity removal need to be determined experimentally for the systems and equipment under consideration.
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PMID:Optimization and scale-up of solvent extraction in purification of hepatitis A virus (VAQTA). 1863 12

The yellow W(V) thiocyanate complex is formed by shaking sodium tungstate solution in 0.2-0.8M potassium thiocyanate and 4-5M hydrochloric acid, with mercury. It is extracted with 2% tribenzylamine solution in chloroform and measured at 410 nm. U, Ti, V, Cr, Fe, Co, Ni, Mn, Al, Pb, Sn, Bi, Pd, Sb and Cu do not interfere. Pt and Mo in amount equal to that of tungsten give errors of up to 0.4 and 2% respectively. The sensitivity is 0.013 mug ml and Beer's law is obeyed up to 24 mug ml .
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PMID:Spectrophotometric determination of tungsten with thiocyanate. 1896 26

A new method is proposed for collecting traces of nickel from aqueous solution by precipitation as the alpha-furildioxime complex and adsorption of this onto microcrystalline naphthalene. The precipitate is collected, dried, and dissolved in chloroform, and the nickel is determined spectrophotometrically at 438 nm. The linear calibration range is 2-35 mug/10 ml. The molar absorptivity is 1.6 x 10(4) l. mole(-1). cm(-1). The main advantage is that the nickel is collected quantitatively after only a few seconds'shaking. The effect of varying pH, amount of reagent, naphthalene or buffer, shaking and standing time, and interferences have been investigated.
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PMID:Spectrophotometric determination of nickel after separation by adsorption of its alpha-furildioxime complex on naphthalene. 1896 60

A simple, rapid and sensitive method has been worked out for spectrophotometric determination of macro and micro amounts of alumina in ceramic raw materials and finished products, including glasses. The method is based on the extraction of aluminum oxinate into chloroform after masking of titanium with chromotropic acid and of iron with ascorbic acid and 1,10-phenanthroline or ferrocyanide at pH 5.2. The absorbance is measured at 385 nm. Interference by Cu, Zn, Cd, Ni and Co, when present, is overcome by stripping them as cyanide complexes by shaking the chloroform extract with potassium cyanide solution. Zr is masked with quinalizarin sulphonic acid and fluoride with BeSO(4).
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PMID:Extraction spectrophotometric method for determination of aluminium in silicates. 1896 58

A method for the extraction-spectrophotometric determination of palladium with 3,4,4a,5-tetrahydro-3,3,4a-trimethyl-7-(substituted)-pyrimido(1,6-a)benzimidazole-1-thiol (PBT) is described. PBT-Pd(II) complex is extracted from an acidic aqueous solution (0.01-0.5M HClO(4)) into a chloroform layer. The absorbance is measured at 438 nm and the molar absorptivity found to be 1.033 x 10(4)M(-1) cm(-1). The complex system conforms to Beer's law over the range 1.9-28.5 mug/ml palladium(II). The effects of pH (2-6), HClO(4) concentration, PBT concentration and shaking time were studied. The ratio of metal ion to ligand molecules in the coloured complex was found to be 1:4. The tolerance limit for many metals have been determined. Finally, the method has been applied successfully to the determination of palladium in synthetic mixtures and in the standard palladium carbon powder (palladium catalyst).
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PMID:Extraction and spectrophotometric determination of Pd(II) with 3,4,4a,5-tetrahydro-3,3,4a-trimethyl-7-(substituted)-pyrimido(1,6-a)-benzimidazole-1-thiol (PBT). 1896 44


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