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PubMedDate not supplied

Total dietary fiber determined as neutral sugar residues, uronic acid residues, and Klason lignin (the Uppsala method): collaborative study.

A joint AOAC/American Association of Cereal Chemists (AACC) collaborative study was conducted to determine by the Uppsala method the dietary fiber content and its composition in various foods. The method includes preparation of a residue by treatment with thermostable alpha-amylase and amyloglucosidase and then ethanol precipitation of solubilized dietary fiber components while leaving low-molecular weight carbohydrates in solution. After acid hydrolysis of residue, neutral polysaccharide residues are determined as alditol acetates by gas-liquid chromatography, uronic acid residues are determined by colorimetry, and ash-free acid-insoluble residue (Klason lignin) is determined gravimetrically. Total dietary fiber, including enzyme-resistant starch, is calculated as the sum of nonstarch polysaccharide residues and Klason lignin. Nine laboratories completed the study, analyzing in duplicate 8 unknown dried products that included 4 cereal products, green peas, potato fiber, carrots, and apples. Total dietary fiber contents of products tested ranged from 4.6 to 84.3%, with an average RSDR value of 8.4% (range, 4.8-11.1%). Total neutral polysaccharide residues ranged from 3.8 to 64.1%, with an average RSDR value of 7.5% (range, 5.4-10.5%). Individual neutral sugars (rhamnose, arabinose, xylose, mannose, galactose, and glucose) and uronic acid residues present at more than 1% generally had good RSDR values (3.3-22.8%), whereas, as expected for Klason lignin, only the wheat bran sample with a high content (16%) had an excellent RSDR value (5.0%). The gas chromatographic-colorimetric-gravimetric method (Uppsala method) for determination of total dietary fiber (as neutral sugar residues, uronic acid residues, and Klason lignin) has been adopted first action by AOAC INTERNATIONAL.

Carbohydrates↗
PubMed1994

[Automatization of colorimetric serum zinc determination using the Bayer RA 1000 autoanalyzer].

A colorimetric method for the determination of zinc in serum was adapted for use with the Bayer RA 1000 autoanalyzer. Zinc is dissociated from proteins by guanidinium hydrochloride and complexed with 2-(5-bromo-2-pyridylazo)-5-(N-propyl-N- sulfopropylamino-)phenol (5-Br-PAPS). Precision (within-run CVs from 1.4 to 4.2%; between-run CVs from 3.5 to 8.1%), accuracy (93 to 103%) and detection limit (1.15 mumol/l) were sufficient for routine determinations. Moreover, results obtained with the proposed Bayer RA 1000 method were in good agreement with those obtained by flame atomic absorption spectrometry (FAAS) which could be considered the reference method. For 119 sera, the correlation coefficient r was found to be 0.958 and the regression line was as follows: serum zinc (RA 1000) = 0.96 serum zinc (FAAS) + 0.8 mumol/l. Moreover, 98% of the differences between colorimetry and FAAS were within the range Md +/- 1.96 SDd, where Md is the mean of the differences and SDd is the standard deviation of the differences.

Autoanalysis↗
PubMed1994

[Determination of total arsenic in food by borohydride reduction colorimetric method].

A method for determination of total arsenic in food by borohydride reduction colorimetry is presented. After samples' digestion, the arsenic is converted into trivalent arsenic by KI-thiourea under heating when the solution's acidity is more than 1.0mol/L. Trivalent arsenic is then reduced by sodium borohydride to arsine gas which can react with AgNO3 in absorbing solution to form a yellow substance whose maximum absorption wavelength is 400nm. The method was applied to the determination of total arsenic in grape wine, carp, dried shrimp, rice powder and lettuce, and the variation coefficients were 13.3%, 12.8%, 8.2%, 12.2% and 7.2%, respectively. The recoveries from dried shrimp, carp and rice powder were 98.0%-112.0%, 82.0%-98.8%, and 84.2%-115.0%, respectively. The method was also applied to the determination of arsenic in reference material rice powder NBS 1568 and the result, 0.37-0.43mg/kg, coincided with the given value 0.41 +/- 0.05mg/kg.

Animals↗
PubMedDate not supplied

[The determination of etatsizin in cadaveric material].

Methods for ethacizine isolation from cadaveric material by acetonitrile acidified with 10% oxalic acid to attain pH 2.0 followed by ether purification have been developed. Extraction photo-colorimetry using methyl orange was used for measurement of ethacizine isolated from cadaveric material.

Anti-Arrhythmia Agents↗
PubMed1994

Influence of thiofedrine on platelet aggregation, intraplatelet cyclic cAMP and malondialdehyde in rats.

Platelet aggregation and cyclic adenosine monophosphate (cAMP) production were studied by turbidimetry and competitive protein binding assay, respectively, in rats. Thiofedrine (Thi) significantly inhibited adenosine diphosphate (ADP)-induced and thrombin-induced platelet aggregation in vitro, with IC50 values of 0.56 and 0.16 mmol/l, respectively. In vivo, Thi 1.25-5.0 mg/kg i.v. significantly inhibited ADP-induced platelet aggregation at rate of 17.1-40.3%. Thi caused a dose-dependent increase in cAMP levels in rat washed platelets. Malondialdehyde (MDA) levels in rat platelets were measured by colorimetry. Thi had an inhibitory effect on thrombin-induced platelet MDA production. The results suggest that the antiaggregatory action of Thi may be related to metabolism of arachidonic acid (AA) and elevation of cAMP levels.

Adenosine Diphosphate↗
PubMed1994

[Automated simultaneous measurements of activity and antigenicity of plasma antithrombin III].

Plasma antithrombin III activity and concentration were measured simultaneously on COBAS MIRA-S by colorimetry using a synthetic substrate and by immunoturbidimetry, respectively, in normal subjects (n = 30), in patients with liver disease (n = 37), and in those with thrombosis (n = 76). The activity/concentration ratio of plasma antithrombin III, in which concentration was represented as the ratio to the mean concentration for normal, was evaluated in each group. Results showed that the ratio was significantly lower in patients with liver diseases (0.76 +/- 0.18, mean +/- SD, p < 0.01) and in thrombotic patients (0.89 +/- 0.18, p < 0.01) than that in normal (1.07 +/- 0.06), demonstrating the predominance of antithrombin III molecules with low activity in the former groups. This simple and rapid (< 10 min) method is applicable for detecting such the constitutional change in plasma antithrombin III.

Adult↗
PubMed1993

[Evaluation of DNA-DNA hybridization method for identification of mycobacteria using a colorimetric microplate kit].

DNA-DNA hybridization was applied for identification of mycobacteria and developed as a kit "microplate hybridization kit" (refers to MPHD) by Kobayashi Pharmaceutical Co. We received test samples of the microplates from the company and examined them for their and reliability using 180 mycobacterial strains of 21 species kept in our laboratory. The results of identification by MPHD were 100% identical to those of biochemical identification in the type or reference strains of mycobacteria, showing good reliability of MPHD method. Among clinical isolates, there were six M. tuberculosis strains which did not show typical characteristics for M. tuberculosis, i.e., niacin test negative or nitrate reduction weak positive, but all of these were identified as M. tuberculosis complex by MPHD method. Some strains from clinical isolates showed difference in identification between MPHD and biochemical methods: M. avium complex, identified biochemically were divided into M. avium and M. intracellulare by MPHD, M. fortuitum complex by biochemical identification were distinguished as M. fortuitum and M. chelonae by MPHD. Further, M. chelonae were separated into M. chelonae subsp. chelonae and M. chelonae subsp. abscessus by MPHD. M. peregrinum has been considered as a synonym of M. fortuitum, but we could distinguish M. peregrinum from M. fortuitum clearly by MPHD method. Thus, it is suggested that M. peregrinum and M. fortuitum are different species. Keys for getting reliable results using the MPHD kit are: (1) appropriate amount of bacteria for use, (2) purification of DNA, (3) enough deproteinization, and (4) appropriate timing to read colorimetry measurement of the plate.

Colorimetry↗
PubMed1995

Chemiluminescent and colorimetric enzymatic assays for the detection of PCR-amplified Salmonella sp. products in microplates.

To improve Salmonella detection, we developed nonradioactive hybridization assays of amplified products from pure Salmonella cultures. Biotin-labeled PCR products were trapped by internal probes covalently bound to CovaLink-NH MicroWells and detected by colorimetric or chemiluminescent enzymatic reactions. The sensitivities of colorimetric assays using peroxidase and alkaline phosphatase were similar to those obtained with an ethidium bromide-stained agarose gel; both procedures allow the detection of 50 Salmonella cells. Chemiluminescence was 10-fold more sensitive than colorimetry.

Alkaline Phosphatase↗
PubMed1996

Sequential microenzymatic assay of cholesterol, triglycerides, and phospholipids in a single aliquot.

The assay of multiple analytes in a single aliquot can be advantageous from both measurement and economic standpoints. The objective of this study was to develop a simple and sensitive microenzymatic method for the determination of three biologically important lipids. Triglycerides (as glycerol), phospholipids (as choline), and total cholesterol (as unesterified cholesterol) were assayed, in that order, by sequential addition of sample, reagents, and microbial enzymes directly into a single microtiter plate well, accompanied by continuous monitoring of a common reporter reaction in which hydrogen peroxide is quantified either by colorimetry with 4-aminoantipyrine and 3-hydroxy-2,4,6-triiodobenzoic acid or by ultraviolet fluorometry with p-hydroxyphenylacetic acid. The detection limit of the method is in the subnanomole mass range for all three lipids. Results obtained with either fluorescence or colored endpoints were in excellent agreement with alternative individual chemical and enzymatic procedures.

Animals↗
PubMed1977

Quantitative determination of thiourea in citrus fruits.

A quantitative method for thiourea determination in orange peels is proposed, with direct reflectance spectrometric measurements on chromatoplates. Thiourea is separated on a silica gel plate with methanol-chloroform (10 + 90), and the spots are characterized with 2,6-dichloroquinone chloroimide; this colorimetric reaction is unstable, so thiourea is quantitated on the chromatogram by direct ultraviolet reflectance spectrometric measurements at 240 nm. Comparison between this method and the AOAC colorimetric method shows interferences and higher results in the colorimetric assay. By slightly modifying the extraction technique, such as purifying the extract on an alumina column, it is possible to decrease these interferences and to avoid erroneous results with the AOAC colorimetric method. For both methods, colorimetry in solution and reflectometry on chromatoplates, applied after the proposed extraction technique, the sensitivity is about 1 ppm and the reliabilities are similar.

Citrus↗
PubMed1996

Colorimetric ELISA measurement of specific mRNA on immobilized-oligonucleotide-coated microtiter plates by reverse transcription with biotinylated mononucleotides.

In this study, alpha-globin mRNA was captured on plastic plates to which alpha-globin-specific oligonucleotides had been covalently immobilized; the captured mRNA was immediately reverse-transcribed into cDNA in the presence of biotinylated dUTP. Addition of alkaline phosphatase-conjugated streptavidin to react with the biotin was followed by addition of substrate (p-nitrophenyl phosphate), and the resulting colorimetric development was measured at 405 nm. Because multiple biotin molecules are incorporated into cDNA during reverse transcription, and because synthesized cDNA is more stable than mRNA, we could successfully quantify by conventional colorimetry the amount of alpha-globin mRNA on the plate within a linear range of 100 pg to 10 ng. This is more sensitive than conventional Northern blotting. Therefore, the present method may be applicable to measurements of specific mRNAs in various test materials.

Animals↗
PubMedDate not supplied

Comparative study of colorimetric and fully automated enzyme-linked immunoassay system for rapid screening of Listeria spp. in foods.

Two enzyme-linked immunoassay (ELISA) systems for rapid screening of Listeria spp. were compared for their use in analysis of spiked foods regulated by the U.S. Food and Drug Administration. The Tecra Listeria kit is a 48 h visual ELISA that detects Listeria spp. through colorimetry. It has been approved for first action by AOAC INTERNATIONAL. The Vitek immunodiagnostic assay system for Listeria (VIDAS LIS) is a fully automated 48 h ELISA that detects Listeria spp. by immunofluorescence. Fifty-two food samples were artificially contaminated with high (11-42 colony-forming units [cfu]/25 g food) and low (2-8 cfu/25 g food) levels of L. monocytogenes and screened by the 2 protocols. Unspiked samples were also assayed as negative controls. Six unspiked samples were found positive for Listeria spp. by both methods: 3 were identified as L. monocytogenes and 3 as L. innocua by official methods. Both ELISA methods detected all spiked samples. One unspiked sample was assayed positive by Tecra and negative by VIDAS LIS. No Listeria spp. were recovered when the sample was tested by the conventional method. No interference due to background fluorescence of food matrixes was observed in the VIDAS LIS method. Results suggest a modified VIDAS LIS preenrichment medium may be used in place of the VIDAS standard medium in the protocol.

Autoanalysis↗
PubMedDate not supplied

[A new property of aspirin and other salicylates. Their capacity for radical generation at the expense of chelating-oxidizing action on iron cations].

It was demonstrated that salicylic acid, by binding ions of ferrous iron, induces its oxidation to the oxide form by molecular oxygen with generation of active forms of oxygen. Salicylic acid may therefore form stable ferrosalicylic complexes only with iron oxide, in which case the affinity of salicylic acid for iron oxide is higher than that of o-phenanthroline and lower than that of EDTA. In the presence of ascorbate in the system with salicylic acid and iron ions continuous radical formation may take place due to alternating cycles of oxidation-reduction iron ions through the combined effect of salicylic acid and ascorbate on them. The initial salicylic acid content in commercial aspirin preparations and its intensive formation at pH values close to the physiological parameters were determined by colorimetry and the inner standard method. After incubation of aspirin preparations at pH close to the physiological values, accelerated oxidation of ferrous iron with formation of active oxygen forms was recorded, which was evidently due to salicylic acid produced as the result of aspirin breakdown under such conditions.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Objective evaluation of Papanicolaou staining.

OBJECTIVE: To evaluate the color of cytoplasm stained by Papanicolaou staining quantitatively. STUDY DESIGN: Cytoplasm photographed under the same conditions was measured for spectral reflection by colorimetry, and the color of the cytoplasm was shown by the L*a*b* color specification. RESULTS: This method enabled us to specify the color of cytoplasm, which was classified in light green, eosin and orangeophilic. CONCLUSION: The variation in the color of cytoplasm by different staining methods was quantified and related to the dyes absorbed by the cytoplasm.

Colorimetry↗
PubMedDate not supplied

Color attributes and accuracy of Vita-based manufacturers' shade guides.

The shades of several tooth-colored restoratives are now keyed to the Vita Lumin shade guide. The purpose of this study was to determine whether manufacturers' shade guides had color attributes that were similar to the Vita Lumin guide to which they are supposedly keyed. The overall color accuracy between the different guides was also compared via colorimetry. Results showed that none of the manufacturers' shade tabs evaluated had all L*, a*, and b* values that were identical to their respective Vita shade tabs. For the shades evaluated, manufacturers' tabs were generally darker than their corresponding Vita shade tabs. When shade guides were compared, the color accuracy of Z100 and Fuji II LC shade guides was significantly better than that of Durafill VS and TPH. Dyract's shade guide was the most accurate and was significantly better than the shade guides of Fuji II LC, Durafill VS, and TPH. The accuracy of manufacturers' shade guides was not consistently product dependent but was shade dependent.

Analysis of Variance↗
PubMed1999

Comparative study of a modified competitive RT-PCR and Amplicor HCV monitor assays for quantitation of hepatitis C virus RNA in serum.

A modified competitive RT-PCR (mcRT-PCR) to measure HCV RNA in serum and the Amplicor HCV Monitor assay were compared. For mcRT-PCR, the RNA extracted was retrotranscribed and coamplified in one step with a known amount of a DNA internal control (IC). Digoxigenin-labeled amplified products were hybridized to specific HCV DNA and IC-DNA probes and quantified by colorimetry. HCV RNA concentration was calculated by plotting the ratio of HCV/IC ODs against a calibration curve. Multiple samples were analyzed in the same round and tedious titration of each sample with a competitor was unnecessary. The mcRT-PCR assay was linear from 6 x 10(3) to 6 x 10(7) copies/ml, whereas Amplicor was linear up to 1-2 x 10(6) copies/ml. HCV RNA was measured in samples from 75 carriers. There was agreement between both methods in type 1 infections but not in type 2 or type 3 infections, in which the values measured by Amplicor were, on average, 15 times lower than those measured by the mcRT-PCR. HCV RNA measured by Amplicor was higher in type 1 infections than in type 2 or 3 infections, but no differences were found when viral load was assessed by mcRT-PCR. The binding efficiency of the Amplicor-probe was greater for type 1 than for types 2 or 3, suggesting Amplicor underestimates the viral load in the latter types. In contrast, the mcRT-PCR is not affected by genotype-related variation of HCV. This study suggests that mcRT-PCR assay is reliable for sensitive and accurate measurement of HCV RNA over a broad range of values independently of the HCV genotype.

Genotype↗