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PubMedDate not supplied

Gas chromatographic method for putrescine and cadaverine in canned tuna and mahimahi and fluorometric method for histamine (minor modification of AOAC Official Method 977.13): collaborative study.

A collaborative study was conducted to test a modification to the AOAC fluorometric method for histamine (AOAC Official Method 977.13) that substitutes 75% methanol as the extracting solvent. All other steps remain unchanged. The extracts prepared with 75% methanol were also used to collaboratively test a gas chromatographic (GC) method for determination of putrescine and cadaverine in seafood. In the GC method, the extracted diamines are converted to fluorinated derivatives, the reaction mixtures are passed through solid-phase extraction columns, and the derivatives are quantitated by electron capture GC after separation on an OV-225 column. Fourteen laboratories using the GC method for putrescine and cadaverine and 16 laboratories using the fluorometric method for histamine analyzed 14 canned tuna and raw mahimahi (including blind duplicates and a spike) containing 0.2-2.6 ppm putrescine, 0.6-9.1 ppm cadaverine, and 0.6-154 ppm histamine. At the 5 ppm level, recoveries ranged from 71 to 102% for putrescine and 77 to 112% for cadaverine; the respective repeatability relative standard deviations (RSDr) were 5.2 and 15%, and the respective reproducibility relative standard deviations (RSDR) were 8.8 and 18%. At the 50 ppm level, histamine recoveries ranged from 84 to 125%, RSDr was 3.6%, and RSDR was 9.4%. The GC method for determination of putrescine in canned tuna and cadaverine in canned tuna and mahimahi has been adopted first action by AOAC INTERNATIONAL, and the AOAC Official Method 977.13, Histamine in Seafood, Fluorometric Method, has been modified.

Animals↗
PubMed1998

[Methods of evaluating SPECT images: the usefulness of the Matsuda's method by the Patlak plot method in children].

Single photon emission computed tomography (SPECT) is a tool to study cerebral blood flow (CBF) kinetics. There are three methods of evaluating SPECT images: visual, semi-quantitative (evaluation of the radioactivity ratio of the cerebral region to the cerebellum [R/CE] or to the thalamus [R/TH]) and quantitative (Matsuda's method by Patlak plot method using 99m Tc-hexamethylpropylene amine oxime radionuclide angiography). We evaluated SPECT images by the quantitative method in 14 patients with neurological disorders and examined the correlation of the results to those obtained by the semi-quantitative method. There was no significant correlation between the R/CE or R/TH ratio and regional CBF except two regions. The evaluation by the semi-quantitative method may have been inappropriate, probably because the cerebellar or thalamic blood flow was not constant in each case. Evaluation by the quantitative method, on the other hand, seemed to be useful not only for the comparison of CBF among normal subjects, but also in the demonstration of progressive changes of CBF in the same case. The Matsuda's method by the Patlak plot method is suitable for examination of children, since it dose not require aortic blood sampling.

Adolescent↗
PubMed1998

Comparison of 2 toothbrushing methods for efficacy in supragingival plaque removal. The Toothpick method and the Bass method.

Plaque removing efficacy was compared between a new toothbrushing method named the Toothpick method and the Bass method. 20 male university dental students participated in the study, which consisted of 2 experiments. Prior to each experiment, all subjects were asked to abstain from all oral hygiene procedures for 48 h. In Exp. I, plaque-removing efficacy was assessed after each participant's mouth had been professionally brushed by a dentist. In this experiment, 2 quadrants were brushed professionally using the Toothpick method, and the remaining 2 quadrants were brushed using the Bass method. The brushing time amounted to a total of 2 min per mouth. In Exp. II, the subjects brushed their own teeth after receiving toothbrushing instruction. A blind examiner assessed dental plaque using a modification of the Quigley and Hein index at 6 sites around each tooth. Toothbrushing using the Toothpick method was found to remove significantly more plaque from proximal tooth surfaces than brushing using the Bass method.

Adult↗
PubMed2004

Comparison of a membrane surface adhesion recovery method with an IMS method for use in a polymerase chain reaction method to detect Escherichia coli O157:H7 in minced beef.

In this study, enrichment procedures and two recovery methods, a membrane surface adhesion technique and an immunomagnetic separation (IMS), were compared for use in conjunction with a multiplex polymerase chain reaction (PCR) method with a view to describing a fast (24 h) and economical test for detection of Escherichia coli O157:H7 in meat samples. The study showed no significant difference between three different enrichment media (BHI, E. coli (E.C.) broth+novobiocin, modified tryptone soya broth (mTSB)+novobiocin) or two incubation temperatures (37 or 41.5 degrees C) for growth of E. coli O157:H7 in minced beef. Minced beef samples inoculated with E. coli O157:H7 at 40 cfu g(-1) were incubated at 37 degrees C for 16 h in E.C. broth+novobiocin reaching numbers of (log(10)7.82-8.70). E. coli O157:H7 were recovered by attachment to polycarbonate membranes immersed in the enriched cultures for 15 min or by immunomagnetic separation. Subsequent treatment of recovered membranes or IMS beads with lysis buffer and phenol/chloroform/isoamyl alcohol was used to extract the DNA from the extracted E. coli O157:H7 cells. The results show when E. coli O157:H7 was present at high levels in the enriched meat sample (log(10)9.6-7.5 cfu ml(-1); >16-h enrichment), the membrane and IMS techniques recovered similar levels of the pathogen and the microorganism was detectable by PCR using both methods. At lower levels of E. coli O157:H7 (log(10)6.4), only the IMS method could recover the pathogen but at levels below this neither method could recover sufficient numbers of the pathogens to allow detection. The conclusion of the study is that with sufficient enrichment time (16 h) the membrane surface adhesion membrane extraction method used in combination with multiplex PCR has the potential for a rapid and economical detection method.

Animals↗
PubMed1988

Evaluation of several creatinine methods in search of a suitable secondary reference method: report from the subcommittee on reference method for creatinine, Nordic Society for Clinical Chemistry.

Several methods for creatinine have been examined by the subcommittee on reference method for creatinine. These include the use of picric acid to precipitate proteins followed by alkalization, or the use of alkaline picrate after protein precipitation and adsorption to Fuller's earth. The first approach was not found to be suitable as a reference method since it was susceptible to matrix effects, fluctuations in temperature and wavelengths. The second approach was less sensitive to these effects but showed variations with different batches of Fuller's earth. The method using high performance liquid chromatography (HPLC) had poor precision, probably because endogenous compounds co-eluted either with creatinine or with the internal standard. The enzymatic method based on the determination of hydrogen peroxide had good accuracy and precision. However, the main disadvantage is that the method is sold as a kit and detailed specifications concerning all the ingredients are not available to permit independent studies using the basic components.

Chromatography, High Pressure Liquid↗
PubMed2006

[Studies on the correlation of the method currently used by the Japanese Society for Medical Mycology and its modified method with the NCCLS M27-A2 microdilution method for azole susceptibility testing of Candida species].

To evaluate the currently used Japanese Society for Medical Mycology (JSMM) method for testing the azole susceptibility of yeasts, the activities of fluconazole and itraconazole were tested against recently collected clinical isolates of Candida spp. (n=946) and compared with the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 microdilution reference method. Favorable correlation with the M27-A2 method was not seen for isolates of C. albicans, C. tropicalis or other Candida spp., particularly their trailing-growth isolates. However, the degree of correlation and agreement of MIC values were markedly improved when testing was performed by the modified JSMM method in which the end-point to be read was changed from IC80 (for the current JSMM method) to IC50. These results suggest that there is an urgent need to revise the current JSMM method.

Azoles↗
PubMed1978

[Comparison of two methods of antibiotic sensitivity tests: gel diffusion and automatic method using ABAC apparatus. I. Variation and dispersion of the two methods (author's transl)].

The authors studied comparatively the sensitivity of 3 bacterial strains (P. Aeruginosa and two E. coli) with regard to antibiotics using an automatic method (ABAC) compared with a gel diffusion technic with impregnated disks. Each strain was tested by both methods 50 to 55 times. The diffusion method was easily reproducible with an average standard deviation of 2.23 mm. Its results were in agreement compared with the average diameter of measurements in 93.3% of cases. The automatic method gave results which agreed together in 95.7% of cases. It is thus reproducible. If one compares it with the results of the diffusion method, considered here as the reference method, we obtained the same response in 86.3% of cases. In 13.7% there was disagreement in interpretation (in most cases, the strain found intermediate in gel diffusion was considered sensitive on autoanalysis).

Anti-Bacterial Agents↗
PubMed1994

[Reestimation of aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio based on JSCC consensus method--changes of criteria for a differential diagnosis of hepatic disorders following the alteration from Karmen method to JSCC method].

We estimated clinical criteria of aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio that is measured by the consensus method of JSCC (Japan Society of Clinical Chemistry) for serum AST and ALT. The JSCC consensus method is closely correlated with both IFCC (International Federation of Clinical Chemistry) recommended method without pyridoxal phosphate and Karmen method recommended by the expert panel of liver function tests in Japanese Society of Gastroenterology. The slopes of the regression line is estimated to be 1.00 and 0.87 respectively. We propose that the decision making value of AST/ALT ratio to differentiate several types of liver diseases should be set to 0.87 measured by JSCC consensus method, instead of 1.0 measured by Karmen method.

Alanine Transaminase↗
PubMed2003

Perugia urodynamic method of analysis (PUMA): a new advanced method of urodynamic analysis applied clinically and compared with other advanced methods.

AIMS: The aim of this study is to compare PUMA curves with different pathologic conditions causing bladder dysfunction in 158 men and 83 women. METHODS: PUMA results in terms of bladder outlet obstruction and detrusor contractility were compared in 92 men with benign prostatic hypertrophy (BPH) and p(ves) congruent with p(det) (i.e., p(abd) congruent with 0) with the results of the urodynamics operator's opinion, the provisional International Continence Society method, Abrams and Griffith's diagram, urethral resistence factor (URA), Schäfer's diagram, and Watt factor. PUMA curves correlated reliably with different pathologic conditions such as obstructive BPH, orthotopic bladder, cystocele, the neurological bladder, and bladder diverticulum. Statistical analysis indicated excellent agreement between PUMA and URA; agreement with other methods was good in cases of obstruction and nonobstruction. In doubtful cases, as diagnosed by standard methods, PUMA agreed only with the Abrams and Griffith's diagram. PUMA and Wmax were in good agreement on detrusor con traction force. Agreement between PUMA and Schäfer's diagram was excellent for patients with detrusor hypercontractility and good for patients with detrusor hypocontractility and normocontractility. PUMA is the only method applicable to women. It is easy to perform. When integrated with other diagnostic tests, it provides realistic data for diagnosis, medical or surgical therapy, and outcome.

Adult↗
PubMed1993

Direct and indirect methods for the quantification of leg volume: comparison between water displacement volumetry, the disk model method and the frustum sign model method, using the correlation coefficient and the limits of agreement.

Volume changes can be measured either directly by water-displacement volumetry or by various indirect methods in which calculation of the volume is based on circumference measurements. The aim of the present study was to determine the most appropriate indirect method for lower leg volume calculation using water displacement volumetry as a 'golden standard'. For 20 male volunteers, age range: 20-35 years, the volume of both lower legs was determined directly by water-displacement volumetry, and indirectly by the frustum sign model method and the disc model method. Calculation of the correlation coefficient and the limits of agreement showed that water-displacement volumetry and the disc model method are interchangeable (r = +0.99, mean +/- 2s = -45 +/- 78 ml), whereas this does not hold for the frustum sign model (r = +0.93, mean +/- 2s = 521 +/- 238 ml). In the clinical situation volume measurement can be valuable for monitoring of the severity of oedema or haematoma occurrence after surgery or severe trauma. This non-invasive diagnostic aid may be a valuable adjuvant means of diagnosis for several volume dependent disorders of the extremities.

Adult↗
PubMed2001

Julia sets for the super-Newton method, Cauchy's method, and Halley's method.

We study numerically and dynamically three cubically convergent iterative root-finding algorithms, namely Cauchy's method, the super-Newton method, and Halley's method. Using the concept of a universal Julia set (motivated by the results of McMullen), we establish that these algorithms converge when applied to any quadratic with distinct roots. We give examples showing the existence of attracting periodic orbits not associated to a root for the super-Newton method and Halley's method applied to cubic polynomials. We include computer plots showing the dynamic structure for each algorithm applied to a variety of polynomials. (c) 2001 American Institute of Physics.

Journal Article↗
PubMed1994

Comparison of two methods of storing breast fine needle aspirates (FNAs) using oestrogen receptor immunocytochemical assay as a method of evaluating the storage methods.

Two methods of storing fine needle aspirates were compared in 14 patients with breast cancer. The methods of storage were: (1) as a Cytospin slide prepared immediately from the aspirated material and stored at -80 degrees C; (2) as a suspension of cells in tissue culture medium, stored at -80 degrees C. The effect of storage on the cells was assessed by means of an oestrogen receptor immunocytochemical assay (ER-ICA). An ER positivity of 100% was obtained by ER-ICA staining of cells after storage method 1, whilst all of the specimens stored by method 2 were ER-negative. The data demonstrate that cells stored in tissue culture medium at -80 degrees C are not suitable for ER measurement. The storage method of choice for specimens intended for ERICA is as a Cytospin slide. The ER status of cells deposited on Cytospin slides prepared immediately and stored at -80 degrees C for 2 years could be demonstrated despite the delay in processing the specimen.

Biopsy, Needle↗
PubMed1996

Calibration of the Ektachem Amylase method using human reference materials and the Phadebas Blue Starch method as an interim reference method.

In a multilaboratory study a consensus was established to calibrate the Ektachem Amylase method to reproduce the results of the Phadebas Blue Starch method. The calibration graph has a slope = 3.39 and intercept = 25. For the Ektachem Amylase method the reaction-rate ratio between salivary and pancreatic amylase was calculated to be 0.89, relative to that of the Phadebas Blue Starch method. A calibration value for the Nordic Amylase Calibrator to be used on Ektachem analysers was determined to be close to 469 U l-1 for the current batch. However, since the difference from the stated value of 460 U l-1 is negligible, the authors recommend the use of the stated value for this and future batches of the Nordic Amylase Calibrator. An error of around 10% introduced by the presence of salivary amylase is comparable to the methods accepted by the Scandinavian Committee on Enzymes. Introduction of a consensus calibration reduced the interlaboratory variation by up to 40% at all levels.

Amylases↗
PubMed2006

Comparative analysis of a modified ecolite method, the colicomplete method, and a most-probable-number method for detecting Escherichia coli in orange juice.

The Ecolite High Volume Juice (HVJ) presence-absence method for a 10-ml juice sample was compared with the U.S. Food and Drug Administration Bacteriological Analytical Manual most-probable-number (MPN) method for analysis of artificially contaminated orange juices. Samples were added to Ecolite-HVJ medium and incubated at 35 degrees C for 24 to 48 h. Fluorescent blue results were positive for glucuronidase- and galactosidase-producing microorganisms, specifically indicative of about 94% of Escherichia coli strains. Four strains of E. coli were added to juices at concentrations of 0.21 to 6.8 CFU/ ml. Mixtures of enteric bacteria (Enterobacter plus Klebsiella, Citrobacter plus Proteus, or Hafnia plus Citrobacter plus Enterobacter) were added to simulate background flora. Three orange juice types were evaluated (n = 10) with and without the addition of the E. coli strains. Ecolite-HVJ produced 90 of 90 (10 of 10 samples of three juice types, each inoculated with three different E. coli strains) positive (blue-fluorescent) results with artificially contaminated E. coli that had MPN concentrations of <0.3 to 9.3 CFU/ml. Ten of 30 E. coli ATCC 11229 samples with MPN concentrations of <0.3 CFU/ml were identified as positive with Ecolite-HVJ. Isolated colonies recovered from positive Ecolite-HVJ samples were confirmed biochemically as E. coli. Thirty (10 samples each of three juice types) negative (not fluorescent) results were obtained for samples contaminated with only enteric bacteria and for uninoculated control samples. A juice manufacturer evaluated citrus juice production with both the Ecolite-HVJ and Colicomplete methods and recorded identical negative results for 95 20-ml samples and identical positive results for 5 20-ml samples artificially contaminated with E. coli. The Ecolite-HVJ method requires no preenrichment and subsequent transfer steps, which makes it a simple and easy method for use by juice producers.

Beverages↗
PubMed1983

[Methods and their evaluation for the estimation of vitamin B6 levels in man. 5. Serum pyridoxal-5-phosphate determination: method and comparison of methods].

Methods and Their Evaluation to Estimate the Vitamin B6-Status in Human Subjects. V. S-PLP-Determination: Method and Comparison of Methods. A method to determine the plasma pyridoxal 5-phosphate (PLP) basing on the enzymatic decarboxylation of 1-14C-l-tyrosine and the measurement of the radio-active 14CO2 is described. Its efficiency is discussed in comparison with other methods. High specificity, precision, accuracy, and sensitivity are demonstrated. The developed equipment allows to analyse a great number of samples and minimizes the risk of radio-active contamination. The commercial apoenzyme preparations are different in quality and require purification. Apoenzyme lots with high genuine content of PLP are useless. Storage tests at 4 degrees C, -18 degrees C, and -196 degrees C show stability of the samples for one day, 30 days, and at least 10 weeks.

Carbon Radioisotopes↗
PubMed1980

[Method of determination of proteins with Coomassie brilliant blue G 250. I. General characteristics and comparative analysis with the biuret method and Lowry's method].

Bradford (1977) described a new sensitive easy rapid method for protein assay, depending on colour change of the stain Coomassie Brilliant Blue G 250. In this study Bradford's method was compared with the Lowry et al. 91951) and biuret methods. Coomassie method appears to be as sensitive as Lowry, as simple as biuret. Another advantage is a very short time of performing.

Methods↗