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PubMed1993

Quantitative analysis of the technetium-99m-DTPA captopril renogram: contribution of washout parameters to the diagnosis of renal artery stenosis.

Retrospective analysis of precaptopril and postcaptopril DTPA renograms from 88 hypertensive patients was performed to refine the quantitative criteria used to diagnose renal artery stenosis (RAS). Of the 88 patients, 45 had RAS and 43 had normal renal arteries at angiography. Using time-activity curves from the essential hypertensive group, diagnostic washout criteria for a positive DTPA renogram were developed. These were based on the 20 and 30 min/peak activity ratios in each kidney. When the washout criteria were retrospectively applied to patient data as a whole, sensitivity and specificity for RAS were 67% and 79%, respectively. When previously described uptake criteria, based on the time to peak activity in each kidney and the GFR ratio between the kidneys, were applied to the same data, sensitivity and specificity for RAS were 89% and 84%, respectively. Quantitative analysis of the DTPA renogram using the time to peak and GFR ratio was both sensitive and specific for RAS. Measurement of 20 and 30 min/peak renal activity ratios did not improve the accuracy of the test.

Angiography, Digital Subtraction↗

PubMed1985

Liquid chromatographic procedure for the quantitative analysis of megestrol acetate in human plasma.

A simple, sensitive, and reproducible high-performance liquid chromatographic (HPLC) procedure was developed for the quantitative analysis of megestrol acetate in human plasma. An internal standard, 2,3-diphenyl-1-indenone, was added to 0.5 mL of plasma followed by extraction with hexane. The residue remaining after evaporation of hexane was reconstituted in methanol and injected onto a mu-Bondapak C18 column. The column was eluted with acetonitrile:methanol:water:acetic acid (41:23:36:1), and the eluant was monitored at 280 nm. Megestrol acetate and the internal standard eluted at 6-7 and 12-14 min, respectively. The peak height ratio (megestrol acetate/internal standard) versus plasma concentration was linear over a range of 10-600 ng of megestrol acetate/mL of plasma, and the limit of detection was 5 ng/mL. The mean intra- and interassay accuracies were within 3% of the actual values. The mean intra- and interassay precision, as estimated by RSD, were 4 and 6%, respectively. Constituents in human plasma and megestrol, a possible degradation product, did not interfere in the assay. The procedure was applied to the analysis of plasma samples from subjects receiving 40 mg of Megace q.i.d.

Chromatography, High Pressure Liquid↗

PubMed1989

Quantitative analysis of amyloid fibril protein in systemic organs of patients with familial amyloidotic polyneuropathy.

The purpose of this study was to develop a quantitative method for variant transthyretin (also called prealbumin) in amyloid-laden tissues of familial amyloidotic polyneuropathy (FAP). The variant transthyretin was extracted by using 70% formic acid solution in which the protein was solubilized completely and rapidly. The quantity of the variant transthyretin was measured by a radioimmunoassay (RIA). An immunoreactive species detected in the tissues of FAP was confirmed to be the variant transthyretin by reverse-phase high-performance liquid chromatography. The quantity of the variant transthyretin in the thyroid gland of 2 FAP patients was 9.90 and 9.76 micrograms/mg tissue, and that of the kidney was 4.03 and 6.27 micrograms/mg tissue, respectively, while its quantity in the liver was only 0.15 and 0.12 microgram/mg tissue. We present here a quantitative analysis of the distribution and predominance of amyloid deposits in systemic organs of FAP.

Adult↗

PubMed1988

Quantitative analysis of immunological reactions on silicon surfaces by multiple-angle Brewster angle reflectometry.

An optical biosensing instrument has been developed for the quantitative analysis of immunological reactions on biochemically sensitized surfaces. It is based on the measurement of reflectance changes of polarized laser light incident on high refractive index substrates at angles close to the pseudo-Brewster angle. Multiple-angle Brewster angle reflectometry (MABAR) has been used to investigate the binding of anti-human serum albumin (a-HSA) to human serum albumin (HSA) coated silicon surfaces. The concentration dependence and reaction kinetics of antibody-antigen complex formation have been studied using red and green He-Ne laser light. A significant increase in sensitivity has been observed with green light.

Antibodies↗

PubMed1980

Quantitative analysis of oxepinac in human plasma, urine and saliva by gas chromatography--mass fragmentography.

A sensitive and specific method is described for the quantitative analysis of 6,11-dihydro-11-oxo-dibenz[b,e]oxepin-3-acetic acid (oxepinac) in human plasma, urine and saliva. Oxepinac and internal standard are extracted from acidified plasma, urine or saliva, converted to the corresponding n-propyl esters and analysed by gas chromatography--mass fragmentography using selected ion monitoring. The method is accurate and precise over the range 100 microgram/ml to 1.0 ng/ml. The method has been applied to the analysis of plasma, urine and saliva from healthy volunteers receiving therapeutic doses of oxepinac.

Acetates↗

PubMed1992

Quantitative analysis of human immunodeficiency virus type 1 antibody reactivity by western immunoblots: evaluation of relative antibody levels in seropositive individuals and mothers.

A quantitative analysis of antibody responses to human immunodeficiency virus type 1 (HIV-1) proteins using Western immunoblots and 125I-labeled protein A is reproducible and can be validated. The antibody levels obtained by Western immunoblots were compared with stoichiometric p24 radioimmunoassay over a wide range of antibody (correlation coefficient, .94; P less than .001). Antibody levels to gp160 and gp120 were validated using purified antigens. Analysis of antibody levels from 31 seropositive individuals revealed a statistically significant correlation between antibody levels to p24 and the other viral proteins except gp120. Anti-gag p24 antibody was strongly correlated with antibodies to other env products, specifically gp41 and gp160. Using the validated assay, HIV-1-infected mothers of infants were found to have highly variable levels of antibody to all viral proteins. Mothers of infected infants did not differ significantly from mothers of uninfected infants in antibody pattern or levels to any viral protein including gp120.

Adult↗

PubMed1986

Quantitative analysis of mouse tyrosinase by enzyme-linked immunosorbent assay.

A sensitive, specific, competitive enzyme-linked immunosorbent assay (ELISA) was developed for quantitative analysis of tyrosinase. Binding sites of anti-tyrosinase antibodies were competed for by purified tyrosinase adsorbed onto microtiter plates and a known (standard) or unknown (sample) amount of tyrosinase in solution. Adsorbed antibodies were detected by goat anti-rabbit IgG F(ab')2 labeled with peroxidase. A sensitivity range of 2.1 to 14 ng (30-200 fmol)/well was obtained. SDS was found to be the most suitable detergent for solubilizing the enzyme. Tyrosinase was extracted from B16 mouse melanoma and assayed by the ELISA. The tyrosinase content per mg melanoma protein was 505 +/- 106 (S.D.) ng. This assay is not only useful for measuring the content of normal tyrosinase in crude extracts but also is possibly applicable to detecting the unprocessed tyrosinases.

Animals↗

PubMed2005

Quantitative analysis of chaotic synchronization by means of coherence.

We use an index of chaotic synchronization based on the averaged coherence function for the quantitative analysis of the process of the complete synchronization loss in unidirectionally coupled oscillators and maps. We demonstrate that this value manifests different stages of the synchronization breaking. It is invariant to time delay and insensitive to small noise and distortions, which can influence the accessible signals at measurements. Peculiarities of the synchronization destruction in maps and oscillators are investigated.

Journal Article↗

PubMed2003

Quantitative analysis of collagen and elastic fibers in the transversalis fascia in direct and indirect inguinal hernia.

PURPOSE: Our previous studies demonstrated structural and quantitative age-related changes of the elastic fibers in transversalis fascia, which may play a role in inguinal hernia formation. To verify whether there were differences in the extracellular matrix between direct and indirect inguinal hernia, we studied the amount of collagen and elastic fibers in the transversalis fascia of 36 male patients with indirect inguinal hernia and 21 with direct inguinal hernia. MATERIAL AND METHODS: Transversalis fascia fragments were obtained during surgical intervention and underwent histological quantitative analysis of collagen by colorimetry and analysis of elastic fibers by histomorphometry. RESULTS: We demonstrated significantly lower amounts of collagen and higher amounts of elastic fibers in transversalis fascia from patients with direct inguinal hernia compared to indirect inguinal hernia patients. The transversalis fascia from direct inguinal hernia patients showed structural changes of the mature and elaunin elastic fibers, which are responsible for elasticity, and lower density of oxytalan elastic fibers, which are responsible for resistance. These changes promoted loss of resiliency of the transversalis fascia. CONCLUSION: These results improve our understanding of the participation of the extracellular matrix in the genesis of direct inguinal hernia, suggesting a relationship with genetic defects of the elastic fiber and collagen synthesis.

Adult↗

PubMed2001

[Nondestructive quantitative analysis of Paracetamoli powder pharmaceutical by artificial neural network and near-infrared spectroscopy].

The application of artificial neural network for pharmaceutical nondestructive quantitative analysis were investigated. Real data set from near infrared reflectance spectra of Paracetamoli powder pharmaceutical were used to build up artificial network to predict unknown samples. The parameters affecting network were discussed. A new network evaluation criterion, the degree of approximation, was employed. Owing to good nonlinear multivariate calibration nature of ANN, the predicted results was reliable.

Acetaminophen↗

PubMed1981

Quantitative analysis of the numerical and lateral distribution of intramembrane particles in freeze-fractured biological membranes.

An improved method is presented for a quantitative analysis of freeze-fractured biological membranes. The analysis provides the numerical distribution of intramembrane particles (IMP) as a function of their diameter and a measure for the lateral IMP-distribution as a function of the IMP-diameter in terms that allow a statistical comparison between different replicas. In analyzing the lateral IMP-distribution a distinction between random, aggregative and dispersive distributions can be made for different IMP-diameter classes. Such an analysis makes the interpretation of the ultrastructural appearance of biological membranes possible in terms of the dynamic behavior of the represented membrane components. The method is demonstrated by comparing the structure of the plasma membrane of synchronized neuroblastoma cells after glutaraldehyde and formaldehyde fixation at pH 6.0.

Animals↗

PubMed2002

An evaluation of a four-channel multiplexed electrospray tandem mass spectrometry for higher throughput quantitative analysis.

A four-channel multiplexed electrospray inlet system (MUX) coupled to a triple quadrupole mass spectrometer was investigated as a higher throughput approach to quantitative analysis. Four discrete samples may be simultaneously analyzed by virtue of a rotating sampler with a concomitant 4-fold increase in analytical throughput. Although absolute sensitivity was reduced using the MUX interface compared with analysis using traditional single electrospray interface, reproducibility of response was shown to be comparable. Source robustness was established for the analysis of both aqueous drug standards and drugs in biological media, and linearity of response for a test compound, diazepam, was demonstrated over 2 orders of magnitude. Analyte-dependent response differences were exhibited between the four channels of the interface, and this led to the overall conclusion that samples to be compared quantitatively must be analyzed through the same sprayer. In addition, each channel must be independently calibrated to afford true quantification. Should a deuterated internal standard be employed, however, quantitative comparisons can be made across channels. An HPLC pumping system providing individual back-pressure regulation to each channel was shown to provide adequate chromatography even in the event of a channel blockage. Furthermore, following multiple injections of biological samples onto the MUX interface, an eluent flow diversion was integrated into the first part of each analytical run. This served to prevent source fouling, and thus, no detrimental effects to response reproducibility or sensitivity were observed.

Clozapine↗

PubMed1997

Quantitative analysis of mu and delta opioid receptor gene expression in rat brain and peripheral ganglia using competitive polymerase chain reaction.

Competitive polymerase chain reaction assays following reverse transcription have been developed for quantitative analysis of delta and mu opioid receptor gene expression. The assay was used to obtain quantitative measurements of mu and delta opioid receptor expression levels in different brain regions and sensory and sympathetic ganglia in the rat. The assays provide accurate estimates of the relative levels of receptor messenger RNAs by the inclusion in the assays of known amounts of internal standards with the same sequence, except for a small deletion, as the target complementary DNA. The amplification products of target and competitor can be distinguished by size, and their amounts measured by densitometry. Expression of mu and delta opioid receptor messenger RNAs in different regions of the rat brain, somatic and visceral sensory and sympathetic ganglia was investigated using this method. In the brain the highest density of delta receptor messenger RNA was detected in the olfactory bulb, followed by the striatum. The mu receptor was expressed at highest levels in the midbrain-hypothalamic region. All the sensory ganglia studied expressed both mu and delta opioid receptor messenger RNAs. In the nodose ganglion we observed the highest level of mu receptor messenger RNA of any structure studied; in the trigeminal ganglion the level was about 10 times lower than that in the nodose ganglion. Among the dorsal root ganglia, mu receptor messenger RNA density was highest in the lumbar region, followed by the thoracic and cervical regions. The sympathetic superior cervical ganglion expressed a very low level of mu message. Delta receptor messenger RNA was detected only in the sensory ganglia, at levels that were considerably lower than in the striatum. The reverse transcription polymerase chain reaction assay is quantitatively reliable for comparison of messenger RNA levels between different RNA extracts, and sensitive enough to permit the detection and assay of mu and delta opioid receptor gene expression in a single pair of sensory or autonomic ganglia from the rat.

Animals↗

PubMed2004

On-line coupling of supercritical CO2 extraction with reversed-phase liquid chromatography for the quantitative analysis of analytes in aqueous matrices.

The first report of on-line coupled supercritical fluid extraction (SFE) with reversed-phase liquid chromatography for the quantitative analysis of analytes in aqueous matrices is described. Two commercial systems (e.g. SFE and HPLC) were connected via a single six-port injection valve. By using water to eliminate residual decompressed CO2 gas in the solid-phase extraction trap, quantitative extraction and transfer were achieved for the target analytes (progesterone, phenanthrene, and pyrene) spiked in water, as well as in real samples (urine and environmental water). During each extraction, no restrictor plugging was realized. Extraction temperature and pressure were optimized. Different amounts of salt were added to the aqueous matrix to enhance ionic strength and thus extraction efficiency. Methanol and 2-propanol were used as CO2 modifiers. Compared with dynamically mixing modifier with the CO2 extraction fluid, pre-spiking the same amount of modifier in the extraction vessel enhanced the recovery approximately 30% for progesterone, phenanthrene, and pyrene due to a "co-extraction effect".

Carbon Dioxide↗

PubMedDate not supplied

Quantitative analysis of HLA-B27 by flow cytometry using CD3 gating in seronegative spondylarthropathies.

OBJECTIVE: To investigate the relationship in patients with spondylarthropathies (SpA) between the clinical features of the disease and quantitative flow cytometric expression of HLA-B27 by CD3 gating. METHODS: We performed quantitative analysis of HLA-B27 antigen by flow cytometry using CD3 gating in 61 patients with seronegative and HLA-B27 positive SpA. The patients included 29 with ankylosing spondy-litis (AS), 29 with undifferentiated spondylarthropathy (uSpA), and 3 with reactive arthritis (ReA). In addition, we compared the fluorescence intensity of HLA-B27 with the clinical characteristics of the patients. RESULTS: The fluorescence intensity of HLA-B27 was significantly higher in patients with AS than in patients with other SpAs (220.5 +/- 13.7% vs 182.8 +/- 11.7%, p = 0.04). However, there were no demonstrable correlations between the quantitative expression of B27 and clinical features such as age, disease duration, results of the Schober test, chest expansion, the WBC count, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). There was also no difference in the quantitative expression of HLA-B27 based on the presence or absence of uveitis, peripheral arthritis or enthesopathy. However, multiple regression analysis showed that age, disease duration and CRP were independent factors influencing the quantitative expression of HLA-B27 in SpA (beta = 0.568, 0.546, -0.437 and p = 0.006, 0.02, 0.04, respectively). CONCLUSIONS: Our data suggest that the quantitative expression of HLA-B27 may be related to some of the clinical features in patients with SpA.

Adolescent↗

PubMed1998

A new HPLC-based method for the quantitative analysis of inner stratum corneum lipids with special reference to the free fatty acid fraction.

The inner stratum corneum is likely to represent the location of the intact skin barrier, unperturbed by degradation processes. In our studies of the physical skin barrier a new high-performance liquid chromatography (HPLC)-based method was developed for the quantitative analysis of lipids of the inner stratum corneum. All main lipid classes were separated and quantitated by HPLC/light scattering detection (LSD) and the free fatty acid fraction was further analysed by gas-liquid chromatography (GLC). Mass spectrometry (MS) was used for peak identification and flame ionization detection (FID) for quantitation. Special attention was paid to the free fatty acid fraction since unsaturated free fatty acids may exert a key function in the regulation of the skin barrier properties by shifting the physical equilibrium of the multilamellar lipid bilayer system towards a noncrystalline state. Our results indicated that the endogenous free fatty acid fraction of the stratum corneum barrier lipids in essence exclusively consisted of saturated long-chain free fatty acids. This fraction was characterized as a very stable population (low interindividual peak variation) dominated by saturated lignoceric acid (C24:0, 39 molar%) and hexacosanoic acid (C26:0, 23 molar%). In addition, trace amounts of very long-chain (C32-C36) saturated and monounsaturated free fatty acids were detected in human forearm inner stratum corneum. Our analysis method gives highly accurate and precise quantitative information on the relative composition of all major lipid species present in the skin barrier. Such data will eventually permit skin barrier model systems to be created which will allow a more detailed analysis of the physical nature of the human skin barrier.

2-Propanol↗

PubMed2003

Quantitative analysis of bilobalide and ginkgolides from Ginkgo biloba leaves and Ginkgo products using (1)H-NMR.

1H-NMR spectrometry was applied to the quantitative analysis of the bilobalide, ginkgolides A, B, and C in Ginkgo biloba leaves and six kinds of commercial Ginkgo products without any chromatographic purification. The experiment was performed by the analysis of each singlet H-12, which were well separated in the range of delta 6.0-7.0 in the (1)H-NMR spectrum. However, the H-12 protons of bilobalide and ginkgolides may have overlapped with H-6 or H-8 protons of the Ginkgo flavonoids. Therefore, the optimum (1)H-NMR solvent for the analysis of the compound was selected through the evaluation of solvent effects on the resolution of these signals from the compounds. Acetone-d(6)-benzene-d(6) (50 : 50) was found to be the best one among the solvents evaluated. The quantity of the compounds was calculated by the relative ratio of the intensity of each compound to the known amount of internal standard (25 microgram), phloroglucinol. This method allows rapid and simple quantitation of underivatized bilobalide and ginkgolides in 5 min without any pre-purification steps.

Cyclopentanes↗

PubMed2006

Quantitative analysis of free fatty acids in rat plasma using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with meso-tetrakis porphyrin as matrix.

Quantitative analysis of free fatty acids was achieved using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with a meso-tetrakis porphyrin matrix. Cesium acetate was employed as a cationizing agent. The MALDI signal was reproducible and dominated by cesiated cesium carboxylates [RCOOCs + Cs]+. The addition of two Cs ions resulted in a mass shift of 264.8 Da for each fatty acid and greatly reduced background peaks. A linear relationship between fatty acid concentration and corresponding fatty acid to internal standard peak intensity ratio was observed for three representative fatty acids analyzed across a concentration range from 4.40 to 150 microM, with correlation coefficients between 0.986 and 0.987. The application of this method was demonstrated with the analysis of free fatty acids in nonfasted and fasted rat plasmas. A total of eight free fatty acids (14:0, 16:0, 16:1, 17:0, 18:0, 18:1, 18:2, and 20:4) were detected. The relative peak height ratios of the fatty acids to the internal standard allow quantitative measurements of the free fatty acids. It was shown that the levels of free fatty acids were higher in fasted rats than in rats in a nonfasted state. This method is simple, sensitive, and fast. Thus, it provides an appealing tool for the analysis of free fatty acids or other low-molecular weight compounds during drug discovery and/or development.

Acetates↗