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At least 1,099 records · Page 61Linked to original sources
PubMed1999

[Fluocinonide Reference Standard (Control 981) of National Institute of Health Sciences].

The raw material of fluocinonide was examined for preparation of the "Fluocinonide Reference Standard (Control 981)". The analytical data obtained were: UV spectrum, lambda max of 237.4 nm; IR spectrum, same as that of the Fluocinonide Reference Standard (Control 841); optical rotation, [alpha]20(D) = + 84.4 degree, thin-layer chromatography, one impurity detected; high-performance liquid chromatography, three impurities detected and total amount estimated to be about 0.20%; loss on drying, 0.15%; assay by HPLC, 99.6% Based on the above results, the raw material was authorized as the Fluocinonide Reference Standard (Control 981) of the National Institute of Health Sciences.

Fluocinonide↗
PubMed1999

[Panorama of the investigation on carotenoids in Brasil: perspectives and needs].

During the last two decades Brazil has produced more than 80 scientific papers on carotenoids, most of which dealing with food composition, development of analytical methodology and the factors that influence composition. Varietal differences, agricultural practices, climate and stage of maturity, as well as food storage, processing and preparation are the main influencing factors. Studies on bioavailability and the functions and actions in health have also been carried out and are expanding. Recently, interest has grown on the degradation of carotenoids with the production of either desirable or undesirable aroma/flavor in foods. For the future, analytical and compositional studies should continue to enlarge the basis for agronomic, nutritional, medical and biotechnological projects. It is fundamental that the quality of analytical data continues to receive top priority, for this can mean the difference between reliable and confounding results, regardless of the sub-area of application.

Animals↗
PubMed2000

Nonparametric evaluation of birth cohort trends in disease rates.

BACKGROUND: Although interpretation of age-period-cohort analyses is complicated by the non-identifiability of maximum likelihood estimates, changes in the slope of the birth-cohort effect curve are identifiable and have potential aetiologic significance. METHODS: A nonparametric test for a change in the slope of the birth-cohort trend has been developed. The test is a generalisation of the sign test and is based on permutational distributions. A method for identifying interactions between age and calendar-period effects is also presented. RESULTS: The nonparametric method is shown to be powerful in detecting changes in the slope of the birth-cohort trend, although its power can be reduced considerably by calendar-period patterns of risk. The method identifies a previously unidentified decrease in the birth-cohort risk of lung-cancer mortality from 1912 to 1919, which appears to reflect a reduction in the initiation of smoking by young men at the beginning of the Great Depression (1930s). The method also detects an interaction between age and calendar period in leukemia mortality rates, reflecting the better response of children to chemotherapy. CONCLUSION: The proposed nonparametric method provides a data analytic approach, which is a useful adjunct to log-linear Poisson analysis of age-period-cohort models, either in the initial model building stage, or in the final interpretation stage.

Adult↗
PubMed2000

[Therapeutic inhibition of platelets in a acute coronary syndrome and in coronary intervention: mechanisms and clinical results].

Platelets play a crucial role in the pathogenesis of atherosclerosis and especially in the final ischemic consequences such as acute coronary syndromes. Furthermore, platelets are central mediators of acute or subacute complications of coronary interventions. Therefore, therapeutic inhibition of platelet function is of major interest in cardiology. The following review describes three different therapeutic strategies for platelet inhibition and provides a representative overview on the clinical results of studies based on these strategies. First, the mechanism of acetylsalicylic acid is described and the strong meta-analytic data demonstrating a convincing positive clinical effect is discussed. Second, the mode of action of the thienopyridines is described and initial clinical results are discussed. Third, the inhibition of the platelet integrin receptor GP IIb/IIIa is described as a potent way to block the final common pathway of platelet stimulation. The structural description of GP IIb/IIIa is followed by a structural classification of the available GP IIb/IIIa inhibitors. Clinical studies, meanwhile including several thousands of patients, are discussed based on representative examples. Finally, unresolved issues regarding the various GP IIb/IIIa inhibitors, such as differences in receptor affinity and specificity, intrinsic activation and GP IIb/IIIa inhibitor induced thrombocytopenia are, discussed.

Abciximab↗
PubMed1975

Some aspects of specimen collection and stability in trace element analysis of body fluids.

Analyses for trace elements in biological fluids are uniquely susceptible to extreme errors unless special precautions are taken during collection, storage, and analysis. The integrity of the specimen may be compromised before it is analyzed, by contamination during collection and processing or by attenuation of the analyte concentration during storage. If this happens, determined values are not valid even though the method of analysis is extremely sensitive and highly accurate. Obstacles to obtaining precise and accurate analytical data arising from these factors are discussed. We consider control procedures applicable at all stages for ascertaining the sources of error and eliminating them.

Body Fluids↗
PubMed2001

An ideal trial to test differential onset of antidepressant effect.

Although various published clinical studies have suggested that some antidepressants may have a more rapid onset of therapeutic effect than others, none of these trials was adequately designed to measure differential time to onset of effect. Thus, existing data do not support claims that one drug reduces the symptoms of depression faster than another. In this article, we propose a study that would be ideal for measuring comparative onset of antidepressant effect. The key features of this ideal trial include (1) a prospective definition of early onset of action, (2) increased frequency of assessment, (3) a data-analytic approach capable of capturing the dynamic nature of symptomatic change, and (4) various strategies to minimize bias and heterogeneity of response.

Antidepressive Agents↗
PubMed1975

Cryptococcus laurentii cell envelope glycoprotein. Evidence for separate oligosaccharide side chains of different composition and structure.

Particulate enzyme preparations of the fungus imperfectus Cryptococcus laurentii catalyze transfer of mannosyl and galactosyl residues from GDP-[14C]mannose and UDP-[3H]-galactose to the same endogenous acceptor. After solubilization with pronase, the major portion of both labels is retarded on Sepharose columns and forms a symmetrical peak, in which 14C and 3H coincide. Label also coincides with endogenous protein and carbohydrate. Both labels bind to Sepharose-Concanavalin A (Con A) and are eluted with alpha-methylglucoside. After beta elimination with NaOH-NaBH4 only 14C label retains binding to Sepharose-Con A; 3H label representing (6-O-alpha-galactosyl)10-O-beta-galactosyl-O-mannitol as previously reported (Raizada, M. K., Kloepfer, H. G., Schutzbach, J. S., and Ankel, H. (1974) J. Biol. Chem. 249, 6080-6086) no longer binds. The [14C]mannose-containing material after beta elimination yields a pentasaccharide and a trisaccharide. Similar penta- and trisaccharides can be isolated following beta elimination of particulate preparations of the organism after pronase treatment. Analytical data suggest that the structure of the isolated pentasaccharides corresponds to that of a pentasaccharide previously synthesized de novo using cell-free enzyme preparations of the organism: 2-O-alpha-mannosyl-6-O-alpha-mannosyl-3-O-alpha-mannosyl-(2-O-beta-xylosyl)-O-mannose (Schutzbach, J. S., Raizada, M. K., and Ankel, H. (1974) J. Biol. Chem. 249, 2953-2958). The trisaccharide has the structure 2-O-alpha-mannosyl-2-O-alpha-mannosyl-O-mannitol. The data are consistent with a glycoprotein structure in which these three types of oligosaccharides are bound to a common polypeptide core through O-glycosidic linkages to threonyl and seryl residues.

Cell Membrane↗
PubMedDate not supplied

[Inflammatory pseudotumor: differential diagnosis of tumors of the 4th ventricle].

INTRODUCTION: An inflammatory pseudotumour is a condition of unknown origin and inflammatory nature. It is rarely found in the CNS. We report a case of inflammatory pseudotumour localized to the IV ventricle and review the clinical characteristics of previously reported cases in order to outline the clinical profile of this condition. CLINICAL CASE: A 40 year old man was admitted to hospital complaining of a subacute condition involving difficulty in speaking and in moving his right arm and leg. On examination he had ocular deviation on initial gaze, a complete right Horner's syndrome, right supranuclear facial palsy, dyssynergy-asymmetry on the right finger-nose test and a dissociated sensitivity disorder of the left arm. On MR of the brain there was a space occupying lesion, nodular in form and fixed to the roof of the fourth ventricle. The histopathological report on the specimen removed by surgery stated it to be an inflammatory pseudotumour. On a MEDLINE search for reported cases of inflammatory pseudotumour of the CNS, 27 were found since 1967. Four cases, including ours, involved masses growing into the interior of the fourth ventricle. CONCLUSIONS: Inflammatory pseudotumour of the CNS is a condition affecting young adults, with a slight male predominance and some association with clinical and analytical data suggesting autoimmune dysfunction. The intraventricular site, particularly within the fourth ventricle, is relatively common (4/28) and is usually associated with clinical features of dysfunction of the posterior fossa and/or intracranial hypertension. We consider that inflammatory pseudotumour should be included in the differential diagnosis of tumours of the fourth ventricle.

Adult↗
PubMed2001

Determination and multivariate statistical analysis of biochemical responses to environmental contaminants in feral freshwater fish Leuciscus cephalus, L.

Modulations of 11 prospective biochemical markers of impacts of aquatic pollutants in liver tissue of chub (Leuciscus cephalus), caught at several sampling sites of a river with various pollution types and rates, were matched against analytical data of concentrations of organochlorine compounds, polycyclic aromatic hydrocarbons (PAHs), and heavy metals. Multivariate principal component analysis (PCA) of the field data showed general patterns of biochemical responses to different types of pollutants and relationships among the biomarkers. Cytochrome P4501A-dependent 7-ethoxyresorufin O-deethylase (EROD) activity, inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin and structurally related planar compounds, was strongly enhanced in the more contaminated areas. Compared with polychlorinated aromatic hydrocarbons, PAHs did not contribute so significantly to EROD induction. Testosterone 6 beta- and 16 alpha-hydroxylase activities, as an expression of the cytochrome P4503A27, were slightly increased at several sites but were significantly decreased in samples from some heavily polluted areas. Recently, these activities have been suggested as potential biomarkers of exposure to contaminants that do not induce cytochrome P4501A. In this study, their inhibition or induction was not associated with a specific class of monitored contaminants, and selectivities of these modulations are still to be investigated. Similar modulations of the prospective biochemical indicators of oxidative stress, including microsomal glutathione S-transferase activity, cytosolic glutathione S-transferase with ethacrynic acid, and glutathione reductase, were demonstrated by PCA. The pattern of the modulations of the microsomal nicotinamide adenine dinucleotide phosphate (NADPH)-dependent lipid peroxidation in vitro differed from the responses of the rest of oxidative stress parameters at some sampling sites. Further biochemical markers of oxidative stress under study, including in vivo lipid peroxidation, in vitro production of reactive oxygen species, and the concentration of metallothioneins did not correlate well with the concentrations of the contaminants. Principal component analysis demonstrated that the EROD activity, glutathione-dependent enzymes, and Fe(II)-enhanced lipid peroxidation formed a suitable battery of biomarkers of exposure.

Animals↗
PubMed2001

[Amperometric detection in the determination of drugs by non-separating flow methods--flow injection analysis and sequential injection analysis].

The present review dealing with the use of various electrochemical detection systems in flow methods of analysis of drugs (such as FIA and SIA techniques). The review covers the period of 1988 to 1998 and involves 78 references. The drugs determined are arranged according to the functional groups undergoing electrochemical transformation; for all the analytes data on the detection conditions, detection limits and ranges of quantitation are included. Advantages and drawbacks of amperometric detection of drugs in flow systems are discussed.

Electrochemistry↗
PubMed2001

Monitoring river sediments contaminated predominantly with polyaromatic hydrocarbons by chemical and in vitro bioassay techniques.

Extracts of sediment samples collected from the Morava River and its tributaries (Czech Republic) were examined for mutagenic, dioxin-like, and estrogenic activities. Moreover, the human leukemic HL-60 cell line was tested as a potential model for the detection of effects of environmental contaminants on cell proliferation and differentiation processes. Analytical data indicate that the sediments were contaminated predominantly with polycyclic aromatic hydrocarbons (PAHs) and phthalate esters. The sums of concentrations of 16 U.S. Environmental Protection Agency priority PAHs ranged from 0.8 to 13.2 micrograms/g and those of phthalates reached up to 3,000 ng/g, while only low levels of chlorinated hydrocarbons were found. The main goal of the present study was to determine effects of PAH prevalence on in vitro bioassays, with special emphasis on dioxin-like activity. The dioxin-like activity was tested using a reporter gene assay based on chemical-activated luciferase expression (the CALUX assay). Significant dioxin-like activity (2.6-40.1 micrograms/g benzo[a]pyrene equivalents and 5.9-48.2 ng/g 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents) was detected in all samples, and the results obtained with various exposure times or with both crude and PAH-deprived extracts indicate that the response was probably caused almost exclusively by the presence of high concentrations of PAHs. This corresponds with results of chemical analyses and indicates that various exposure times would allow a discrimination between dioxin-like activities of persistent compounds and easily metabolized aryl hydrocarbon (Ah) receptor inducers. Only sediment extracts containing the highest concentrations of PAHs were mutagenic, as determined by the umu assay. Estrogenic activity was found in several samples (4.75-22.61 pg/g estradiol equivalents) using cells stably transfected with an estrogen-responsive element linked to a luciferase promoter. Noncytotoxic doses of extracts had no effects on HL-60 cell proliferation, while two of the tested crude extracts significantly enhanced their all-trans retinoic acid-induced differentiation. These activities were not associated with phthalate esters and/or PAHs. Our results indicate that cellular and biochemical in vitro assays based on various specific modes of action may yield data complementary to results of mutagenicity tests and that they could be useful in environmental risk assessment. High levels of PAHs are apparently associated with dioxin-like and mutagenic activities rather than with estrogenic activity.

Biological Assay↗
PubMedDate not supplied

[Detection of the cholinesterase inhibitor tacrine and its main metabolites].

Tacrine, a cholinesterase inhibitor for symptomatic treatment of minor to moderate dementia, and its primary metabolites 1-hydroxy-tacrine and 4-hydroxy-tacrine were studied by means of thin-layer chromatography, UV spectroscopy and gas-chromatography/mass spectroscopy. The analytical data (corrected hRf values, UV spectra in solution as well as reflectance spectra, high-pressure liquid chromatography data, GC retention indices and EI mass spectra) including various derivatization methods are described.

Biotransformation↗
PubMed2000

[Thiamine Hydrochloride Solution Reference Standard (Control 991) of National Institute of Health Sciences].

The raw material of thiamine hydrochloride solution was examined for preparation of the "Thiamine Hydrochloride Solution Reference Standard (Control 991)". The analytical data obtained were: assay by HPLC, 101.0%; spectrophotometric assay, 100.4%. Based on the above results, the raw material was authorized as the Thiamine Hydrochloride Solution Reference Standard (Control 991) of the National Institute of Health Sciences.

Government Agencies↗
PubMed2000

[Tocopherol Acetate Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of tocopherol acetate was examined for the preparation of the "Tocopherol Acetate Reference Standard (Control 001)". Analytical data obtained were: IR spectrum, same as that of the Tocopherol Acetate Reference Standard (Control 974); specific absorbance, E/cm% (284 nm) = 43.7; thin-layer chromatography, no impurities were detected until 50 micrograms of the loaded raw material; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.6%; assay by HPLC, 101.7%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 001).

Chromatography, High Pressure Liquid↗
PubMed2000

[Tocopherol Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of tocopherol was tested for the preparation of "Tocopherol Reference Standard (Control 991)". Analytical data obtained were: IR spectrum, same as the Tocopherol Reference Standard (Control 941); specific absorbance, E/cm% (292 nm) = 72.9; thin-layer chromatography, no impurities were detected until 50.0 micrograms; high-performance liquid chromatography (HPLC), trace amounts of five impurities were detected and the total amount was estimated to be less than 1.4%; assay by HPLC, 99.9%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Standard (Control 991).

Chromatography, High Pressure Liquid↗
PubMed2000

[Prednisolone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material for prednisolone sodium phosphate was examined for the preparation of the "Prednisolone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: pH, 7.9; optical rotation, [alpha]D20 = +98.0 degrees; UV spectrum, lambda max of 248 nm and specific absorbance in ethanol at 248 nm = 306.7; IR spectrum, same as that of the Prednisolone Sodium Phosphate Reference Standard (Control 892); thin-layer chromatography, five impurities were detected at 200 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 3.7%; residual solvent, 0.0% (ethanol) and 0.0% (hexane); loss on drying, 2.7%. Based on the above results, the raw material was authorized as the Prednisolone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

Chromatography, High Pressure Liquid↗