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At least 685 records · Page 38Linked to original sources
PubMed1989

The hinge axis: evaluation of current arbitrary determination methods and a proposal for a new recording method.

A proposed arbitrary method of recording the hinge axis based on the correlation between the profile width of the face and the kinematic axis was compared with three commonly used arbitrary methods. The investigation was carried out on 51 individuals. The kinematic point was recorded by the use of a kinematic locator. The different points of emerging axes were photographed at a fixed distance by using a magnification photoapparatus. The proposed method showed a regular distribution around the kinematic axis. Furthermore, this method clearly illustrated that its highest concentration was in the posteriosuperior quarter around the true axis. The proposed technique was found to be more accurate than the other techniques.

Adult↗
PubMed1988

Comparison of an inductively coupled plasma-atomic emission spectrometry method for the determination of calcium, magnesium, sodium, potassium, copper and zinc with atomic absorption spectroscopy and flame photometry methods.

Serum calcium, magnesium, copper and zinc concentrations obtained from the analysis of 77 serum samples by inductively coupled plasma-atomic emission spectrometry (ICP-AES) are compared with the results obtained using atomic absorption spectroscopy (AAS). Similarly, serum sodium and potassium levels from the analysis of the same samples by ICP-AES are compared with the levels obtained by flame photometry. For each metal, we compare the results from both methods with a linear regression program that assumes error in both variables. The regression analysis shows that the ICP-AES method gives slightly higher calcium, copper, and zinc results and lower magnesium results than the AAS methods, and lower sodium and potassium results than the flame photometry method. Except for sodium, the correlation (r) between the results is very high (greater than or equal to 0.958), indicating that the ICP-AES results could be corrected to be equivalent to the atomic absorption or flame photometry results. The ICP-AES has the advantage of requiring less preparation and analysis time, and additional elements could be determined simultaneously in the same sample.

Blood Specimen Collection↗
PubMed1986

Elution-band relaxation method. A method to analyze isomerization kinetics by HPLC and application to protein denaturation-renaturation.

We present a novel method, the 'elution-band relaxation method', to analyze quantitatively reversible isomerization kinetics by elution chromatography, taking advantage of the high resolution and speed of high-performance liquid chromatography (HPLC). The kinetic information is obtained by measuring the first temporal moments of chromatograms of molecules undergoing isomerization and analyzing their dependence on the column length or flow rate. The major advantage of this method is that it is applicable to reactions as fast as the time of elution in HPLC, a speed which has not been attained previously in analysis of isomerization reactions based on the chromatographic property of molecules. We describe the method and report an experimental application to the denaturation-renaturation kinetics of bovine pancreatic ribonuclease A as an example.

Chromatography, High Pressure Liquid↗
PubMed1988

Comparison of the absolute calibration method with the method of standard addition for the determination of halothane in blood by gas chromatographic headspace analysis.

As long-term exposure to exhaled halothane can be a cause of hepatitis and/or damage to the liver, the determination of halothane in blood is important in clinical practice. Gas chromatographic headspace analysis appears to be the most successful method. In the present study, two methods of quantitative evaluation of the analysis were compared by statistical treatment and direct comparison. The absolute calibration method was found to be unsuitable since it yields entirely unreliable results. This is due to different contents of lipoid and other components in the blood of the normal population, and this influences the vapour phase concentration of halothane and results in different values for the slopes of calibration curves for different blood samples. The standard addition method gives reliable results.

Cholesterol↗
PubMed1990

Development of a laboratory robotic system for automated bioanalytical methods--I. The determination of theophylline in human plasma: a comparison between the robotized and manual method.

The quality of bioanalytical methods is often determined by the quality of sample preparation. Using a robot for sample treatment may give better results than manual sample preparation, since the robot lacks human behaviour and incidental errors that are part of it. The use of a laboratory robot has the additional advantage of giving each sample the same analytical history, resulting in better reproducibility. An automated method has been developed for the analysis of drugs in plasma using a laboratory robot. Theophylline was used as a probe drug. Sample preparation was automated with a Zymate II robot, followed by separation and quantitation on an HPLC-system. The robotic method showed a good correlation with the manual method, while sample throughput was doubled.

Chemistry, Clinical↗
PubMed2005

Comparison of the belly board device method and the distended bladder method for reducing irradiated small bowel volumes in preoperative radiotherapy of rectal cancer patients.

PURPOSE: To determine the most effective method to reduce the irradiated small bowel volume when using a belly board device (BBD), a distended bladder (DB), or both in patients with rectal cancer undergoing preoperative pelvic radiotherapy (RT). METHODS AND MATERIALS: The study involved 20 patients with rectal cancer who were scheduled to receive preoperative pelvic RT. Patients were asked to empty their bladders and then drink 300 mL of water 2 h before the treatment planning computed tomographic (CT) scan. To identify the small bowel, an oral contrast solution (450 mL) was given 1 h before the CT scan. Two sets of transverse images were taken at 1-cm-thickness intervals with patients in the prone position with or without the BBD. After voiding, two additional sets of CT scans were obtained in prone positions with or without BBD. The conventional three-field treatment plan, composed of a 6-MV photon posterior-anterior field and 15-MV photon opposed lateral fields with wedges of 45 degrees, was made using a three-dimensional treatment planning system. The beam weights of the three-field plan were equal. The volume of irradiated small bowel was calculated for doses between 10% and 100% of the prescribed dose at 10% intervals. For each 10% dose increment, the effect of the BBD and the DB on the irradiated volume was analyzed using Kruskal-Wallis, Wilcoxon signed rank, and Wilcoxon rank-sum tests. RESULTS: All patients underwent four sets of CT scan under the conditions of four different methods as follows: Group I = empty bladder without the use of belly board; Group II = empty bladder with the use of belly board; Group III = distended bladder without the use of belly board; Group IV = distended bladder with the use of belly board. We found that the volume of irradiated small bowel decreased in the order of Group I, Group II, Group III, and Group IV at all dose levels (p < 0.05). Compared with Group I, the mean volume reduction rate (reduced volume) of irradiated small bowel in Group II varied between 14.5% and 65.4% (15.5-80.4 cm(3)), in Group III it varied between 48.1% and 82.0% (21.6-163.1 cm(3)), and in Group IV between 51.4% and 96.4% (28.6-167.1 cm(3)). CONCLUSIONS: The DB was more effective than the BBD for reducing the volume of irradiated small bowel in rectal cancer patients receiving pelvic RT. The combination of the BBD and DB showed an additive effect and was the most effective method for reducing the irradiated small bowel volume.

Adult↗
PubMed2006

Potential of a simple solid-phase extraction method coupled to analytical and bioanalytical methods for an improved determination of microcystins in algal samples.

Artemia assays and protein phosphatase assays are commonly used for the screening of microcystins (MCs) in algal samples instead of the standard mouse toxicity assay. However, it has been shown that their results are often biased because of the matrix effects. To eliminate the possible interferences in the algal matrices, a new solid-phase extraction (SPE) method using silica gel as a sorbent was developed and evaluated. Results show that this SPE method could not only reduce the toxicity of the Microcystis samples towards brine shrimp by 50-80% but also eliminate 90-100% of the endogenous phosphatase activity from Spirulina and Chlorella samples, thus improving the determination of microcystins in algal samples using either of the two bioanalytical methods. The application of this SPE method as an off-line cleanup for high-performance liquid chromatography (HPLC) with UV detection is also described in this study. After SPE, the HPLC chromatograms of Microcystis samples have clear baselines that have no interferences with the analyte peaks.

Animals↗
PubMed1980

Comparison of manual methods of determination of albumin in human cerebrospinal fluid by the bromcresol green and immuno-precipitation methods.

Simultaneous determinations of albumin concentrations in human cerebrospinal fluid were made by three different manual methods: bromcresol green dye-binding technique of Doumas et al., a modification of the latter with color measurement shortly after the addition of dye as proposed by Ingwersen and Raabo and finally by an immuno-precipitation technique. Results obtained by the immuno-precipitation method correlated significantly with the dye-binding method of Doumas et al., (r = 0.93) and the procedure of Ingmersen and Raabo (r = 0.94). Data from the two dye-binding techniques correlated significantly with one another also (r = 0.98). However, the immuno-precipitation technique gives albumin values lower than the dye-binding procedures. The latter presumably estimates other proteins which can also bind bromcresol green. The data corroborates the conclusions of earlier investigators that immuno-precipitation method is more specific for albumin assays.

Adult↗
PubMed2003

The rate of ectopic pregnancy for 24,589 quinacrine sterilization (QS) users compared to users of other methods and no method in 4 provinces in Vietnam, 1994-1996.

OBJECTIVE: To determine the rates of ectopic pregnancy with the use of quinacrine sterilization (QS) compared to other methods and no method (non-users). METHODS: Four provinces were selected for their above average numbers of women who had undergone QS: Nam Dinh, Nam Ha, Hai Duong and Hung Yen. Case histories related to surgical treatment of all ectopic pregnancies in these 4 provinces from 1994 through 1996 were collected from all hospitals by researchers from the Ministry of Health in June 1997. Using a questionnaire designed for this study, 120 physicians interviewed every woman in her home who had had an ectopic pregnancy during this period. If deceased, a family member was consulted. All interviews were completed in September 1998. The numbers of users of each method and nonusers were calculated from service statistics and demographic data. RESULTS: Based on 2,551,355 woman-years of exposure, the rate of ectopic pregnancy among users per 1000 woman-years was calculated to be: 0.26 with QS; 0.42 with surgical sterilization (TL) and IUD; 0.45 with the Pill; 0.50 with condoms; 0.78 relying on withdrawal; and 1.18 among non-users. CONCLUSION: Ectopic pregnancy rates for QS, TL, IUD and the Pill were similar and much lower than the rate for non-users of contraception.

Adolescent↗
PubMed1998

Continuous particle size distribution analysis with dynamic light scattering. MAXAMPER: a regularization method using the maximum amplitude for the average error and the Lagrange's multipliers method.

This work deals with a new method to evaluate the scattered light intensity distributions with particle size by means of photon correlation spectroscopy. Basically, the data analysis consists in: 1) To find the least squares solution (L2 norm), and 2) To find the solution that is not significantly different from the least squares solution (within a certain significance level) that simultaneously minimizes the sum of the modulus of the residuals (L1 norm). A simple procedure is achieved by using the Lagrange's multipliers method. The two aspects that debilitate CONTIN (a rather empirical regularization based on the continuity of the distributions and the non-suitable use of the Fisher's F test) are prevented in this work, granting more meaningful results. The method was applied to simulated curves, in several typical situations (mono-modal and bi-modal, narrow and broad distributions). The quality of the results is better for narrower mono-modal distributions and bi-modal distributions having well separated peaks, as expected. Latex beads (nanospheres) having 114 nm in diameter were used to test the method in experimental conditions. MAXAMPER better reproduces monodispersed distribution profiles than CONTIN and the first moments of the distributions are in agreement with the expected value in most of the analysis.

Algorithms↗
PubMed2000

Occurrence of pathogenic Yersinia enterocolitica in Norwegian pork products determined by a PCR method and a traditional culturing method.

From October 1997 to April 1998, a survey was conducted to assess the occurrence of pathogenic Yersinia enterocolitica in Norwegian pork products, using a traditional culturing method and a PCR assay. A total of 300 pork samples was examined. Five slaughterhouses in the Norwegian Meat Cooperative were represented with 249 samples and another 51 samples were obtained from retail outlets in the city of Oslo. Using the NMKL method, Y. enterocolitica 0:3 was isolated from six (2%) of the samples, while the PCR method indicated presence of pathogenic Y. enterocolitica in 50 (17%) of the samples. The results indicate that a reduction has occurred in the prevalence of pathogenic Y. enterocolitica in Norwegian pork products, as compared to a previous Norwegian study conducted in 1988-1989. The study also highlights the need for further development and improvement of methods applied for the detection of pathogenic Y. enterocolitica in foods.

Animals↗
PubMed2002

A combination of an extrapolation method and a benchmark method to develop quantitative health targets for Japan.

The aim of the present study was to propose a methodology to formulate quantitative health targets which combined an extrapolation method and a benchmark method, and to estimate the targets for mortality rates (Mb) for selected causes of death by the year 2010 in Japan. Using the extrapolation method, based on the nationwide Mt from 1988 to 1997, the Mt in 2010 was predicted using a regression model. Using the benchmark method, the paired-mean of the age-adjusted mortality rates (Mts) of the top five prefectures among 47 prefectures was calculated as the benchmark. Combining the predicted mortality and the benchmark mortality, year 2010 targets were determined. As a results year 2010 targets as percentages compared with Mt in 1997 for cancer at all sites, stomach cancer, lung cancer, colo-rectal cancer, liver cancer and stroke were estimated to be 93, 52, 94, 102, 53 and 52% for males, and 84, 43, 86, 82, 60, and 45%, for females, respectively. The methodology presented in this article could be used as a standard procedure to formulate realistic quantified health targets, which can be adopted to develop health policies in nations, regions and communities.

Benchmarking↗
PubMed1985

Improved direct injection method and extractive methylation method for determination of valproic acid in serum by gas chromatography.

Two simple methods for the determination of valproic acid in serum by gas chromatography are described. One is a direct injection method. To the serum sample are added an acetonitrile solution including an internal standard and hydrochloric acid. The sample is deproteinized and after centrifugation valproic acid in the supernatant is measured in the free form by direct injection into the gas chromatograph. The other is an extractive methylation method. To the serum sample are added an internal standard solution and a counter-ion solution, and the mixture is extracted into methylene chloride containing methyl iodide. Valproic acid is extracted into methylene chloride and simultaneously the methylation reaction proceeds. After centrifugation, an aliquot of the lower layer without evaporation is injected into the gas chromatograph. Both methods have been applied successfully to monitoring routine serum levels of valproic acid.

Chromatography, Gas↗
PubMed1998

Multi-residue method for non-steroidal anti-inflammatory drugs in plasma using high-performance liquid chromatography-photodiode-array detection. Method description and comprehensive in-house validation.

A multi-residue high-performance liquid chromatography (HPLC) method with photodiode-array detection is presented for the determination of 12 non-steroidal anti-inflammatory drugs (NSAIDs) in plasma. This method has been validated under the consideration of actual alpha- and beta-errors according to an in-house validation concept based on a fractional factorial experiment. A wide range of matrices and other influencing factors have been included in the validation experiment. In order to assess the method's performance the power curve, which demonstrates the detection power of the analytical method, was computed and CCalpha and CCbeta values were calculated.

Animals↗
PubMed1999

Evaluation of the H-point standard additions method (HPSAM) and the generalized H-point standard additions method (GHPSAM) for the UV-analysis of two-component mixtures.

The H-point standard additions method (HPSAM) and two versions of the generalized H-point standard additions method (GHPSAM) are evaluated for the UV-analysis of two-component mixtures. Synthetic mixtures of anhydrous caffeine and phenazone as well as of atovaquone and proguanil hydrochloride were used. Furthermore, the method was applied to pharmaceutical formulations that contain these compounds as active drug substances. This paper shows both the difficulties that are related to the methods and the conditions by which acceptable results can be obtained.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Comparison of the susceptibility testing of clinical isolates of Mycobacterium tuberculosis by the XTT colorimetric method and the NCCLS standards method.

The susceptibility or resistance of clinical isolates of Mycobacterium tuberculosis were determined by a method incorporating the 2,3-bis(2-methoxy-4-nitro-5-sulphophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and compared with results obtained by the National Committee for Clinical Laboratory Standards approved standard method (M24-T2). One hundred percent of all isolates demonstrated agreement between the susceptibility and resistance to isoniazid, rifampicin, and ethambutol obtained by the two methods, suggesting that the XTT-based method could provide a useful means for the rapid determination of antimycobacterial susceptibility of clinical isolates of M. tuberculosis.

Antitubercular Agents↗
PubMedDate not supplied

Automatic particle pickup method using a neural network has high accuracy by applying an initial weight derived from eigenimages: a new reference free method for single-particle analysis.

The single-particle analysis is a structure-determining method for electron microscope (EM) images which does not require crystal. In this method, the projections are picked up and averaged by the images of similar Euler angles to improve the signal to noise ratio, and then create a 3-D reconstruction. The selection of a large number of particles from the cryo-EM micrographs is a pre-requisite for obtaining a high resolution. To pickup a low-contrast cryo-EM protein image, we have recently found that a three-layer pyramidal-type neural network is successful in detecting such a faint image, which had been difficult to detect by other methods. The connection weights between the input and hidden layers, which work as a matching filter, have revealed that they reflect characters of the particle projections in the training data. The images stored in terms of the connection weights were complex, more similar to the eigenimages which are created by the principal component analysis of the learning images rather than to the averages of the particle projections. When we set the initial learning weights according to the eigenimages in advance, the learning period was able to be shortened to less than half the time of the NN whose initial weights had been set randomly. Further, the pickup accuracy increased from 90 to 98%, and a combination of the matching filters were found to work as an integrated matching filter there. The integrated filters were amazingly similar to averaged projections and can be used directly as references for further two-dimensional averaging. Therefore, this research also presents a brand-new reference-free method for single-particle analysis.

Animals↗
PubMed1983

A minimal apparatus method for counting bacteria: comparison with reference method in surveying beef carcasses at three commercial abattoirs.

In two surveys of three commercial abattoirs a minimal apparatus method for making bacterial counts, the "loop-tile' method, detected the same trends in bacterial numbers on beef carcasses as the ISO reference method applied to the same samples. Both methods showed the carcasses from one abattoir, that with an export license, to carry consistently higher numbers of bacteria, and one of the four sites sampled on each carcass to be consistently dirtier than the other three.

Abattoirs↗