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PubMed1990

Light has a greater effect on direct bilirubin measured by the bilirubin oxidase method than by the diazo method.

We compared the effect of light on direct-reacting bilirubin (DBIL) measurement by the bilirubin oxidase (EC 1.3.3.5; BOX) method and by the Jendrassik-Gróf diazo method. DBIL concentrations determined by the BOX method in the sera of hyperbilirubinemic infants treated with phototherapy yielded falsely higher values than those by the direct diazo method. A similar tendency was noted when DBIL concentrations in infants' sera irradiated with light in vitro were determined by both methods, although by HPLC none of these sera had detectable DBIL (i.e., conjugated plus delta bilirubin). In general, DBIL concentrations after photoirradiation remained unchanged when measured by the diazo method, but significantly increased when the BOX method was used. Indeed, photoirradiation gave rise to material that acted like a photobilirubin product, which was oxidized at pH 3.7 and therefore was measured as DBIL. Such false increases in DBIL values generated by the BOX method may have clinical diagnostic implications in monitoring jaundiced neonates and in differentiating between physiological jaundice and incipient pathological jaundice.

Azo Compounds↗

PubMed1989

A new commercial method for the enzymatic determination of creatinine in serum and urine evaluated: comparison with a kinetic Jaffé method and isotope dilution-mass spectrometry.

We evaluated a new, simple, enzymatic kinetic method from Wako Chemicals GmbH in comparison with a kinetic Jaffé method by using isotope dilution-mass spectrometry (ID-MS) as a reference method. An ID-MS-calibrated serum standard was used. Both the enzymatic and the Jaffé method correlated well with ID-MS, except for sera with high concentrations of bilirubin. Ethyl acetoacetate, acetone, and glucose in serum interfered somewhat with the Jaffé method but not with the enzymatic method. We conclude that the present enzymatic method has merit as compared with a Jaffé method for routine work, but is more expensive.

Amidohydrolases↗

PubMed1989

[Clinical methods for evaluating infarct size and its anatomic correlations. Study carried out in 193 cases. III. Comparison of data on the evaluation of the infarct size using the QRS score and a method of maximal creatine kinase determination in the serum].

AIMS: To compare two methods concerning the clinical evaluation of infarct size--one using a QRS score, the other based on peak Ck values--applied to the same population. CONCEPT AND PLACE OF THE STUDY: to determine--based on previously established correlations between a QRS score and the anatomic total infarct size on one hand, and between the peak CK values and the anatomic recent infarct size on the other hand--which myocardial infarction subgroup constitutes the best indication for each method. The study took place in a Coronary Care Unit of a Central Hospital. MATERIAL AND METHODS: 193 patients who died successively of acute myocardial infarction through out 4 years were studied. After establishing the exclusion critéria, the QRS score was calculated according to the method of Selvester modified by Wagner, and peak CK values were evaluated. Infarct size, either recent or old, was determined by means of an anatomical method developed by the authors and based on Hackel's and Alonso's previous works. Correlations were established between data from each clinical method and those from the anatomical method. Several myocardial infarction subgroups were considered for comparison of the correlations found in each subset. RESULTS AND CONCLUSIONS: As long as QRS score was regarded, significant correlations were found between the evaluation by QRS score and anatomical infarct size in the subgroups of patients with severe pump failure, prior myocardial infarction, or total loss of ventricular muscle mass of at least 20 percent; however, a significant correlation was missing when the whole myocardial infarction group was taken into consideration. When peak CK value were considered, a weak significant correlation was found between the evaluation by enzyme determination and anatomical infarct size in the whole group of patients, but a stronger correlation was present in the subgroups of patients with survival longer than 24 hours, anterior wall myocardial infarction, free wall cardiac rupture, or first acute myocardial infarction. In conclusion the choice of the method to be used in the clinical evaluation of infarct size should take into account the type of population beeing studied, and follow the results obtained in different myocardial infarction subgroups as mentioned above.

Creatine Kinase↗

PubMed1989

[New method for preventing spinal headache (prophylactic blood patch method)].

After spinal anesthesia, early ambulation frequently caused spinal headache. If the patient was discharged on the day of the operation, spinal headache occurred very frequently. With epidural anesthesia, if the dura was erroneously punctured with the needle, headache often occurred. In order to prevent spinal headache, we tried the Blood Patch Method during operation (Prophylactic Blood Patch Method). Epidural catheterization and spinal tap were simultaneously performed. The epidural catheter was threaded 3 cm cephalad in the epidural space. Five ml Venous blood of the patient was injected through the epidural catheter (Blood Patch Method). Epidural puncture was performed one spinal segment cephalad (A Method) or one spinal segment cauded (B Method) from the site of spinal puncture. The prophylactic Blood Patch Method was very effective in preventing spinal headache after the dural puncture. Especially B Method, in which blood was injected near the dural pore, was much more effective than A Method.

Anesthesia, Obstetrical↗

PubMed1987

[Evaluation of assay methods for isepamicin sulfate (HAPA-B) in body fluids. Bioassay, HPLC and EIA methods].

Assay methods including microbiological assay (bioassay), high performance liquid chromatography (HPLC) and enzyme immunoassay (EIA) for isepamicin sulfate (HAPA-B), a new aminoglycoside antibiotic, in body fluids were studied. The most suitable bioassay method was double layer agar-well method using Bacillus subtilis ATCC 6633 as the test organism on plate consisting of a seed-layer of nutrient agar at pH 8.0 and a base-layer of nutrient agar supplemented with 0.4% sodium chloride. Sensitivities in bioassay, HPLC and EIA methods for plasma concentration were 0.08 microgram/ml, 0.20 microgram/ml and 0.05 microgram/ml, respectively. Plasma and urinary concentrations after intramuscular administration of HAPA-B at the dose of 200 mg to healthy volunteers were measured with these 3 methods. The HPLC and the EIA methods yielded values which compared favorably to the bioassay method. Using the bioassay method, HAPA-B levels in human plasma and urine samples were found to be stable at least for 15 days at -20 degrees C.

Aminoglycosides↗

PubMed1988

Ten electrophoretic methods compared with a selected method for quantifying lactate dehydrogenase isoenzymes in serum.

Using the Selected Method of McKenzie and Henderson (Selected Methods Clin Chem 1983;10:59-67) as a reference method, we compared the performance of 10 commercially available methods for determination of lactate dehydrogenase (LD, EC 1.1.1.27) isoenzymes. Results were expressed as percentage of total LD activity, as determined with two different types of densitometers shown to have an average difference less than 1.4% for each isoenzyme. All methods gave generally comparable results, as judged by Bland-Altman plots and correlation analyses. However, in general, estimates by the commercial methods for LD-1, LD-2, and LD-3 were lower, and for LD-4 and LD-5 were higher than with the Selected Method. The overall CV was less than 20% for all methods and isoenzymes, except for LD-4 and LD-5 by the Beckman Paragon, Helena LD-VIS, Gel LDH, Gel PC, and Iso Dot, Gelman LDH Isozyme, and Sebia Hydragel assays, for which it was greater than 20%. Overall, accuracy was best with the Helena Iso Dot and LD-VIS assays, followed by the Corning LD Flur assay; accuracy was poorest with the Gelman LDH Isozyme, Sebia Hydragel, and Beckman Paragon assays.

Electrophoresis↗

PubMed1984

[The evaluation of anti-native dna antibodies. Comparison of two methods of dosage, study of reproducibility, and diagnostic value of each method].

The duplicatibility of dosing anti-native (double-stranded) DNA antibodies using Farr's radioimmunological method (RIE) and indirect immunofluorescence on Crithidia luciliae (IF-CL) has been demonstrated in the literature and from a multicenter study undertaken in 10 immunological laboratories. The duplicatibility of tests run at the same time and also between tests done at different intervals by RIE in our laboratory was better than that by IF-CL. The coefficients of maximum change were respectively 3% (variation in results during one run of the test), and 6% (variation in results between different runs of the test) for the RIE method and 34% (variation during one run) and 38% (variation between different runs) using the IF-CL method. This multicenter study showed that the duplicatibility of Farr's radioimmunological test was good among the different laboratories, only antibody levels near the upper limit of normal giving some discordant results were found in 91%, the discordant results being due to falsely-positive or falsely-negative tests, and sometimes also to the differing affinity of the anti-native DNA antibodies in the two methods. The sensitivity of both methods in making a diagnosis of systemic lupus erythematosus from the literature varies from 60 to 98% for the RIE method and from 44 to 98% for the IF-CL method. The predictive value of a positive test between these two methods varies from 65 to 100% depending on the series, which means that there are other conditions than systemic lupus erythematosus (SLE) (rheumatoid arthritis, Sjögren's syndrome, hepatitis...) where anti-native DNA antibodies can be found.

Adult↗

PubMed1981

Analytical methods for sulfonamides in foods and feeds. II. Performance characteristics of sulfonamide methods.

Important factors in interpretation of methods for sulfonamides in tissues are value of the blank, use or omission of recovery factors, and precision of the methods. For determining sulfonamide in tissues, no interlaboratory collaborative studies have been performed to provide reproducibility parameters. By assuming comparability with other tissue residue methods at equivalent concentrations, it may be anticipated that the coefficient of variation within-laboratories of the Bratton-Marshall method is about 15% at concentrations of a fraction of a part per million. It is estimated that the limit of reliable measurement of the Bratton-Marshall method is about 0.2 ppm, varying with the individual laboratory. This value is higher than the tolerance it is intended to enforce. Obviously, the method in this case has been stretched beyond its original claimed capabilities. This method also has high blanks and low recoveries. Assignment of sufficient resources to the solution of the problem by regulatory agencies has resulted in methods capable of handling the sulfonamide residue problem at 0.1 ppm.

Animal Feed↗

PubMed1995

[A study of rCBF measurement with autoradiography (ARG) method using N-isopropyl-p-[123I]iodoamphetamine (IMP) and SPECT--comparison of rCBF values between look-up table (TLU) and ARG methods, and evaluation of venous blood samplings as a substitute for arterial blood sampling].

Regional cerebral blood flow (rCBF) values obtained by the TLU method with two 123I-IMP SPECT scans and one point arterial blood sampling and rCBF obtained by the ARG method with one 123I-IMP SPECT scan and fixed distribution volume (Vd) values were compared in 17 cases. A case with post ischemic hyperperfusion or luxury perfusion was not observed in our cases. The correlation coefficients between rCBF values and Vd values obtained by the TLU method were 0.49 (p < 0.001) in 184 ROI without hypoactive areas on the early image, and 0.61 (p < 0.001) in 207 ROI with hypoactive areas, respectively. A high rCBF value with a low Vd value was not observed in any region. Mean Vd value was 44.0 +/- 7.0 (mean +/- SD) in all regions. The correlation coefficients between rCBF values using the TLU method and those using the ARG method with Vd fixed at 44 and 50 were also 0.98. Error of the rCBF value was larger in the region of high rCBF, however, noticeable error of the rCBF value was not observed in the ARG method. The ARG method is more convenient for quantifying rCBF. Venous blood radioactivity at 10 min after 123I-IMP infusion was smaller than arterial blood radioactivity, and the blood activity in the distal vein was larger than that in the proximal vein. The ratio of venous blood activity to arterial blood activity was 0.92 +/- 0.04 (mean +/- SD) at the back of the hand, however, the ratio was a variant in each case. Arterial sampling was thought to be a reliable method to obtain more stable and precise rCBF.

Aged↗

PubMed1993

Candidate reference methods for determining target values for cholesterol, creatinine, uric acid, and glucose in external quality assessment and internal accuracy control. I. Method setup.

In Germany, the target values for External Quality Assessment (EQA) and internal accuracy control are determined by Reference Methods for several analytes, including cholesterol, creatinine, uric acid, and glucose. We present candidate Reference Methods for these compounds, based on isotope dilution-gas chromatography--mass spectrometry methods that have been developed at INSTAND, one of the two official Germany EQA reference institutions. Each Reference Method target value is calculated from six independent measurements performed on three different days. The mean method CVs ranged from 0.66% for glucose to 0.96% for creatinine. The inaccuracy (bias) of the methods is < 0.7%, as compared with the Standard Reference Material 909 of the National Institute of Standards and Technology. The maximum total error of a Reference Method value, including the 95% confidence interval and systematic errors, is < 2.3%. The presented candidate Reference Methods have been successfully used to set target values in the German EQA scheme and the internal accuracy control of routine laboratories.

Blood Glucose↗

PubMed1996

[The significance of free-type PSA and complex-type PSA in patients with prostatic carcinoma--the characteristics of ACS-PSA method compared with that of Delfia- and Eiken-PSA method].

We studied the clinical significance of free-type prostate specific antigen (PSA) and bound-type PSA in serum of the patients with prostatic carcinoma and benign prostatic hypertrophy. The levels of PSA, gamma-seminoprotein and prostatic acid phosphatase (PAP) in 17 healthy adult males, 20 patients with benign prostatic hypertrophy and 23 patients with prostatic carcinoma were measured by ACS-PSA, Delfia and Eiken-PSA method. The levels of PSA in serum from prostatic carcinoma patients was significantly elevated as compared with that from benign prostatic hypertrophy. Linear regression analysis of the data showed that, although overall correlations were well, different assays gave different PSA concentrations. We have studied the forms of PSA in serum by gel filtration technique and measured PSA levels in each fractions using three methods. Moreover, the characteristics of ACS-PSA method was compared with that of Delfia and Eiken-PSA method. Two peaks of PSA were detected on the elution profiles from three prostatic carcinoma patients sera. Those were estimated complex-type PSA (90kDa) and free-type PSA (30kDa). The complex-type PSA fractions detected by ACS-PSA method were almost identical with that detected by Delfia-PSA method, while free-type PSA fractions detected by ACS-PSA method were greater quantity than those by Delfia and Eiken method. Many factors were contributory to the difference between the assay kits on serum complex-type PSA and free-type PSA levels. The present results suggest that there are some quantitative differences in the immunorecognition of complex-type PSA and free-type PSA between the assay kits.

Adult↗

PubMedDate not supplied

[Individualized monitoring of the therapy with gentamycin using pharmacokinetic methods. Which method to choose?].

Gentamicin has an excellent cost/efficacy ratio for gram negative infections treatment. Its use is often limited in clinical practice by its narrow safety margins and a high incidence of toxicity. Gentamicin related nephrotoxicity is a major adverse effect, mostly in patients with other concomitant potential risk factors. As many other Authors we have found in our Internal Medicine Service during 1992 a gentamicin related nephrotoxicity incidence of 22.5%. Various empiric methods and nomograms have shown a significant incidence of error in predicting individualized gentamicin dosage regimens. Pharmacokinetics methods have demonstrated much better results regarding efficacy and toxicity. The aim of this prospective study carried out during 1993-1994 was to individualize by pharmacokinetics methods dosage regimens of gentamicin in patients with one or more concomitant risk factors of nephrotoxicity. The purpose of pharmacokinetics dosage regimens has been to achieve trough serum concentrations of gentamicin in therapeutics range-0.5 to 2 micrograms/ml-on the first 24 to 48 hours of treatment, and the maintenance in this range during all the treatment, avoiding both toxic and under therapeutic levels. The incidence of gentamicin related nephrotoxicity has been evaluated in this population. Twenty patients were studied: 18 males and 2 females aged 59.6 years (19 to 85). All had one or more potential risk factors for nephrotoxicity-65 years or more: 13, previous renal failure: 6, other nephrotoxic drugs: 10, diuretics: 4, dehydration: 5, congestive heart failure: 5, diabetes: 3, hypertension: 3. For the first 10 patients gentamicin dosage regimens have been determined by Sawchuk-Zaske pharmacokinetics method and for the subsequent 10 patients by Bayesian method. The two subpopulations had no significant differences regarding mean age, sex and potential risk factors for nephrotoxicity. Results of Sawchuk-Zaske method: 53 trough gentamicin serum concentration were obtained; 86.8% were within the therapeutic range, 7.5% were toxic and 5.7% were under therapeutic. Results of Bayesian method: 44 determinations of gentamicin through concentrations were obtained; 86.3% within therapeutic range, 2.4% were toxic and 11.3% were under therapeutic. A great variability in pharmacokinetic patient's profile has been found and explains the great variability of individualized dosage regimens of gentamicin (30 to 320 mg/day). No patients had gentamicin related nephrotoxicity. Both pharmacokinetics methods lead to a efficient and save employment of gentamicin in patients with previous renal failure and other potential risk factors for nephrotoxicity.

Adult↗

PubMed1997

[Comparison of the DNA-GEN Probe PACE 2 method and the LCR method for the detection of Chlamydia trachomatis in the female genital tract].

OBJECTIVE: Comparison of two methods of so-called rapid assessment of Chlamydia trachomatis in the urogenital system, i.e. the hybridization method GEN-Probe PACE 2 and the amplification LCR (ligase chain reaction) method. In 1995-1996 the authors made a screening examination to detect Chlamydiae in the urogenital tract by means of the hybridization method GEN-Probe PACE 2 and the amplification LCR method in selected groups of patients of the Second Gynaecological and Obstetric Clinic, First Faculty Hospital, Prague. The methods were evaluated as to their sensitivity. The examinations of the samples were made in the serological laboratory of the First Dermatological Clinic of the First Faculty Hospital Charles University, Prague. The amplification method is twice as sensitive as the hybridization method.

Adult↗

PubMed1998

The regional Monte Carlo method: a dose calculation method based on accuracy requirement.

In this work we propose the regional Monte Carlo (RMC) method of dose calculation. This method combines the Monte Carlo (MC) algorithm and a non-MC algorithm (such as the convolution method) for optimal speed and accuracy in dose calculation for both photon and electron beams and for various irradiation and patient geometries. For specific regions in the geometry where high accuracy is required but difficult to obtain with analytical or empirical calculations, such as critical organs surrounded by complicated inhomogeneities, the MC algorithm is used. For regions with simple geometries, or where a high degree of dose accuracy is not critical, the non-MC algorithm is used to increase speed. There are two aspects of the RMC method. The first one involves determining critical regions and boundaries, and the other involves the actual implementation and mixing of the two computational algorithms. Two examples of different geometries are used to illustrate the different ways to apply the RMC method. The possibility to extend the method to more complicated geometries and inhomogeneities, as well as the ability of the method to incorporate different calculation algorithms, are also discussed.

Algorithms↗

PubMed1989

[Studies on the method of measurement of odorants dissolved in water--the simplified head space method].

An improved and simplified Head Space Method was devised for measurement of the concentration of odorants dissolved in waste water, and this method was examined to determine whether it was applicable for this purpose or not. This method is taken into consideration the variableness of liquid concentration and of gas pressure resulting from the volatilization of odorants and aqueous vapor to the atmosphere. By this method, the constants of hydrogen sulfide, dimethylsulfide and trimethylamine were measured under various temperatures and pHs. As a result of comparison with the measured values obtained by the Stripping Method and those from the heretofore used Head Space Method, this method appeared to be fairly applicable.

Hydrogen-Ion Concentration↗

PubMed1992

[Comparative study of single-point method and multipoint method in the measurement of estrogen receptor and progesterone receptor in breast cancer].

A comparative study of estrogen receptor (ER) and progesterone receptor (PgR) by single-point method and multi-point method in dextran coated charcoal assay (DCC) was carried out in 50 and 47 cases of breast cancer, respectively. Taking 10 fmol/mg protein as the positive value, the conformation rate of both methods in ER measurement was 96.0% (48/50) with r = 0.978 by linear regression analysis (P less than 0.001). In PgR measurement, the conformation rate of both methods was 95.7% with r = 0.988 (P less than 0.001). Statistically, the difference between single-point method and multi-point method in the ER and PgR measurements was not significant (P greater than 0.5) both in rank-sum test and in paired t-test. The authors suggest that ER and PgR of breast cancer samples be measured with single-point method for its simplicity and less tumor tissue required.

Breast Neoplasms↗

PubMedDate not supplied

Evaluation of three methods for measurement of femoral neck anteversion. Femoral neck anteversion, definition, measuring methods and errors.

A variety of methods exist for determining femoral neck anteversion. There is, however, no consistent definition or reference method by which the correctness of the measurements can be determined. In this report the precision of a specific definition of femoral neck anteversion is estimated by means of a reference method. Three different radiologic measuring methods based on fundamentally different principles are evaluated by comparison with this reference. It is concluded that: 1) The Dunlap/Rippstein method can be recommended as the standard method. 2) Computed tomography may have substantial sources of error. 3) Methods based on arbitrary projections have poor precision.

Femur Neck↗

PubMed1976

[The fecal flora of man. IV. Communication: Comparison of the newly developed method with the old conventional method for the analysis of intestinal flora (author's transl)].

The results of 42 fecal flora analysis of healthy adult men were compared by using a newly developed method and an old conventional method. Statistical estimate indicate, that with the new method the total counts and the counts of bifidobacteria, catenabacteria (eubacteria and anaerobic lactobacilli), peptostreptococci, and clostridia (except Cl. perfringens) as well as the occurences of peptostreptococci and spirillaceae were significant higher than with the use of the old method. On the other hand the counts and occurences of bifidobacteria, veillonellae, Cl. perfringens, Megasphaerae and aerobes were similar with both method. With the new method the total counts of feces of healthy adult men nubmered 1-2 X 10(11) per g wet weight, and fastidious anaerobes, such as bacteroides, catenabacteria and peptostreptococci, were always occurred as predominant flora. The results suggest that the conventional anaerobic jar method is inadequate for the isolation of fastidiuos anaerobes and indicate that the use of modified medium 10 in combination with strict anaerobic technique is necessary for the analysis of fecal flora.

Adult↗