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PubMed1998

Prostatic cancer: role of color Doppler imaging in transrectal sonography.

OBJECTIVE: The aim of this study was to assess the roles of transrectal color Doppler and gray-scale sonography in revealing prostatic cancer, using biopsy as the reference standard. SUBJECTS AND METHODS: Two hundred fifty-six patients referred for urologic studies underwent transrectal sonography using gray-scale and color Doppler scanning. All abnormal areas shown on gray-scale or color Doppler sonography or both were targeted and biopsies were performed. The patients also underwent random sextant biopsies. All biopsies were individually correlated with histopathologic findings and all results were analyzed. RESULTS: Cancer was found on biopsy in 100 patients (39%), and equivocal sonographic results or prostatic intraepithelial neoplasia was found in 22 other patients (9%). In 16 of the patients in whom cancer was detected, the tumors were correctly revealed only with color Doppler sonography. These 16 patients had a mean Gleason score of 6.4 (range, 5-8). Biopsy findings in these 16 patients showed eight patients with extensive lesions, three with moderate lesions, and five with minimal lesions. However, in nine other patients with cancer (9% of cancers detected), both gray-scale and color Doppler sonography failed to reveal lesions that were found on sextant biopsy. An analysis showed that, although highly sensitive, color Doppler sonography was somewhat less specific than gray-scale sonography. CONCLUSION: Color Doppler sonography should become a routine part of transrectal sonography of the prostate gland to improve detection and targeting of lesions. The practice of performing random sextant biopsies should also continue.

Biopsy↗
PubMed2004

[Characterization method for metallothioneins by reversed-phase liquid chromatography coupled with electrospray ionization mass spectrometry].

Mammalian metallothioneins (MTs) usually have two major isoforms, MT-1 and MT-2, existing in tissues because of the genetic polymorphism. Metallothionein isoforms and sub-isoforms were characterized with a hyphenated technique of reversed-phase liquid chromatography (RPLC) coupled with electrospray ionization mass spectrometry (ESI-MS). The MT-isoform separation was carried out using a C8 narrow-bore column Vydac C8 (250 mm x 2.1 mm i.d., 5 microm, 30 nm). Buffer A was 5 mmol/L ammonium acetate in water (pH 6.0) and buffer B was 5 mmol/L ammonium acetate in methanol-water (1:1, v/v) (pH 6.0). A linear gradient elution was used by increasing buffer B from 10% to 37.5% within 40 min. The flow rate was set at 0.20 mL/min. The tentative formulas of MT isoforms and subisoforms were interpreted with the measured masses at the vicinity of apexes in total ion current chromatogram of ESI-MS and the reference data reported previously. The method was validated with the standard reference materials of MT-1 and MT-2. The results indicated that many MT species interpreted were in good agreement with the reference data reported. The MT sample from rabbit liver was measured with the established method. The results, of which the apo-MT was used by acidification of the sample for simplifying the mass spectra, showed that there were species of MT isoforms and subisoforms in rabbit livers.

Animals↗
PubMed2006

New methods in the assessment of diagnostic procedures.

In many countries diagnostic tests compose a growing part of healthcare costs, although there are very low standards for their use and for diagnostic studies and evaluations. Reference standards often do not exist. Diagnostic research needs careful consideration of the clinical situation, and should take into account that diagnosis is a multivariable process. Various study designs to evaluate diagnostic procedures are presented.

Diagnostic Techniques and Procedures↗
PubMedDate not supplied

Capillary microhematocrit measurement as a screening test for anemia in children.

The spectrophotometric measurement of hemoglobin performed with a well standardized instrument using venous blood is widely accepted as a reference standard for anemia. In developed countries automated electronic counters are used instead. However, this method of determining anemia is not practical for screening in developing countries as it requires special skill or expensive equipment to obtain the specimen or to perform the test. The primary objective of this study was to determine the feasibility of using capillary microhematocrit measurement as a screening test for anemia. The 104 patients examined ranged in age from 6 months to 6 years; 65 were males and 36 females. Sixty one of the 104 cases (58.7%) were below 2 years of age and the other 43 cases (41.5%) were older than 2 years. Hemoglobin values ranged from 2.7-13.5 g/dl and capillary microhematocrit ranged from 9-41%. Analysis of the result showed a significant correlation between the capillary microhematocrit values and the capillary hemoglobin values (r = 0.99 and p less than 0.001). The sensitivity of the microhematocrit method for detecting anemia was 91.11% and the specificity was 89.83%. The predictive value for a normal (negative) microhematocrit was 92.98% and the predictive value for a low (positive) microhematocrit was 87.23%. We conclude from this study that the capillary microhematocrit measurement method can be appropriately used as a screening test for anemia.

Anemia↗
PubMed1990

Effect of serum lyophilization on the rate constants of enzymatic methods for measuring cholesterol.

We determined the equilibrium absorbances and rate constants for two enzymatic methods, aca (DuPont) and RA-1000 (Technicon), used in determining cholesterol in reconstituted lyophilized serum. The lyophilized materials included two serum pools, three control materials, a College of American Pathologists' survey material, and Standard Reference Material no. 909. We calibrated the reagents with aca standards for cholesterol (DuPont). The difference in the mean concentrations of cholesterol (aca - RA-1000) was -0.09 g/L overall and was not statistically significant by analysis of variance. The mean rate constant for all materials was 0.23 min-1 for the aca and 1.42 min-1 for the RA-1000, significantly different (P less than 0.001). Lyophilization causes lower results for the aca method than for the Ra-1000, because the reaction rate for the aca method is slower and has not reached equilibrium when the final absorbance reading is made.

Cholesterol↗
PubMed1986

A tissue culture assay for diphtheria toxicity testing.

A tissue culture assay system in microtitre plates using a Vero cell line has been compared with the traditional guinea pig skin reaction test to detect residual toxicity during the diphtheria toxin detoxification procedure. A standard batch of untreated diphtheria toxin was used as a reference standard in each of the assays. The tissue culture assay proved to be sensitive, specific, economical and reproducible and offers an alternative to the use of guinea pigs in testing for any residual toxicity in diphtheria toxoid samples.

Animals↗
PubMed1998

Appropriate imaging before carotid endarterectomy.

The question of which imaging method to use before performing carotid endarterectomy is a common and practical issue confronted by vascular surgeons. The imaging modalities of duplex ultrasonography, angiography, computed tomography (CT) and magnetic resonance angiography (MRA) have all been used in the preoperative assessment of the patient scheduled for carotid endarterectomy. This article focuses on these 4 modalities, with particular emphasis on the advantages and disadvantages of duplex ultrasonography versus angiography. The emergence of duplex ultrasonography as the sole preoperative imaging test has generated controversy among vascular surgeons and other specialists who deal with patients with carotid artery disease. Angiography, which has been the "gold standard" imaging test in the past and has been the reference standard in the large, randomized controlled trials, imposes a small but definite risk of stroke and death. Duplex ultrasonography can be used as the sole preoperative imaging test on a selective basis, provided that there is institutional validation and ongoing quality assurance. Although MRA is not widely available, the combination of MRA and duplex ultrasonography can provide similar diagnostic accuracy to angiography in some institutions. Routine CT appears to be unnecessary but is useful in certain circumstances.

Carotid Stenosis↗
PubMedDate not supplied

Instrumental neutron activation analysis of biological samples.

The elemental compositions of 18 biological reference materials have been processed, for 14 stepped combinations of irradiation/decay/counting times, by the INAA Advance Prediction Computer Program. The 18 materials studied include 11 plant materials, 5 animal materials, and 2 other biological materials. Of these 18 materials, 14 are NBS Standard Reference Materials and four are IAEA reference materials. Overall, the results show that a mean of 52% of the input elements can be determined to a relative standard deviation of +/- 10% or better by reactor flux (thermal plus epithermal) INAA.

Animals↗
PubMed1996

[Standardization of the methods of lipid determination according to WHO in the regional project of prevention of cardiovascular diseases in Friuli-Venezia Giulia].

BACKGROUND: The recognition of dyslipidemias as a major modifiable risk factor for atherosclerosis and coronary heart disease underlines the need to obtain precise and accurate assay results of plasma lipids. Today the use of automatic laboratory methods and of internal quality control favours the precision of the results but does not guarantee accuracy. The efficiency of a laboratory can be ensured by a standardization programme, systematically monitoring precision and accuracy by means of independent internal and external quality control, international reference standards (e.g. those of CDC-NHLBI and WHO) and protocols to identify and reduce the errors due to biological variability and pre-analytical factors. After the foundation of the Regional Project for Prevention of Cardiovascular Diseases in Friuli-Venezia Giulia, a lipid standardization programme was set-up, covering the 20 chemico-clinical laboratories of the Region. The programme was directed by the International WHO-MONICA-Lipid Reference Centres of Prague-Udine. METHODS: During the years 1993-1994, three sets of lyophilized human serum samples were dispatched to each laboratory for the blind evaluation of total cholesterol, triglycerides and HDL-cholesterol. The samples were obtained by the combination of three serum pools at least at different lipid concentration. The first set included 20 samples to be tested in 5 weeks, the second set included 30 samples to be tested in 8 weeks and the third set included 21 samples to be tested in 9 weeks. The assay results were sent to the Prague-Udine WHO-MONICA Centres where they were computerized and evaluated, particularly considering precision for each set, estimated by the variation coefficient (i.e. standard deviation/mean value of the measurements per cent) and accuracy (the bias was computed as mean of the measurement minus the reference value/reference value per cent). RESULTS: In the three assay series for total cholesterol, almost all the laboratories showed the variation co-efficient (precision) to be less than the WHO-MONICA limit of 3.7% (for a cholesterol level of 250 mg) (Tab. II) and in 8 cases out of 20, less than the CDC limit of 3%; the accuracy bias was less than the WHO-MONICA limit of 5% in 17 laboratories out of 20 and less than the CDC limit of 3% in 11 cases out of 20. For the HDL-cholesterol standardization programme the reference values were based upon the phosphotungstate method. However, the pools were also controlled by the other precipitation methods used in the 20 participating laboratories: 11 laboratories worked within the WHO-MONICA limits of precision and accuracy (respectively 6.5% and 7.5%) in at least two of the three sets. Concerning triglycerides, the regional laboratories showed a greater variability and, though most of the variation coefficients were within the WHO-MONICA limit of 5%, half of the accuracy biases were greater than the limit of 10%. The bias of the measurement average of all the laboratories was excellent for total and HDL-cholesterol, not quite good but acceptable for triglycerides. Laboratory performance improved progressively from the first to the last set, on more than one occasion. CONCLUSIONS: The lipid standardization experience carried out in the framework of the Regional Project for Prevention of Cardiovascular Disease demonstrates that it is possible to set up a wide and co-ordinated collaboration with laboratories of an entire region with positive and improving results. For this global quality control system, the resource allocated is limited but widely rewarded by the community benefits in terms of assay reliability and savings at medical care level, basic research and population studies.

Cardiovascular Diseases↗
PubMed1972

The partial thromboplastin (cephalin) time test.

Nine partial thromboplastin (cephalin) reagents have been compared in a parallel investigation of groups of patients on ;long-term' anticoagulants, a group with moderate haemophilia, and patients on heparin infusion. Results with the seven commercial reagents and a human cephalin extract have been correlated with those of a specially prepared and standardized reference preparation of human brain origin. The comparison was similar in principle to that of the prothrombin time thromboplastin standardization using the British Comparative Thromboplastin (BCT). Results, which for comparative purposes were expressed as ratio of patients' cephalin times to control cephalin times, varied greatly in all three groups. In the oral anticoagulant group some of the commercial reagents were particularly insensitive to the ;intrinsic' clotting defect. The correlation between the ;standardized preparation' and the other reagents was not good and the use of a reference cephalin material for quality control of cephalin time tests does not appear promising. In moderate haemophilia the commercial reagents were either relatively poor at picking out the clotting defect compared with the ;standardized preparation' or gave such a bad endpoint that the results were not dependable. The poor endpoint also limited the dependability of the results of all but the ;standardized preparation' and two of the commercial reagents in controlling heparin administration. In view of these standardization difficulties, which cannot apparently be resolved by the use of reference material, there is need for bulk, routine supplies of a sensitive, standardized cephalin reagent giving good reproducible endpoints. The method for the provision of such material in a recently introduced national supply scheme is described.

Blood Coagulation Tests↗
PubMedDate not supplied

A new preconcentration and separation method for flame atomic absorption spectrometric determinations of some trace metal ions on a Diaion HP-20 column.

A preconcentration/separation method for determination of Cr(III), Cd(II), Bi(III) and Co(II) has been proposed. The analytes were adsorbed on a column filled Diaion HP-20 resin as metal-8-hydroxiquinoline complexes and desorbed from the column by using 10 ml of 1M HNO3 in acetone. The influences of some analytical parameters such as pH, amounts of oxine, type of eluent etc on the recoveries of chromium, cadmium, bismuth and cobalt were discussed. Effects of the various alkaline salts on the recoveries of the investigated ions were also examined. The method was applied for the determination of Cr(III), Cd(II), Bi(III) and Co(II) contents of table salt samples, some chemical grade alkaline salts produced in Turkey and a stream sediment standard reference material sample (GBW 07309) with satisfactory results (recoveries > 95%, relative standard deviations < 9%). The limit of detection for analyte ions (3s, N = 20) was between 23-305 ng/g.

Environmental Monitoring↗
PubMed2006

Strategies for plasma proteomic profiling of cancers.

Despite a voluminous literature on potential protein biomarkers and a compelling need for diagnostic tests based on biomarkers to detect cancers at much earlier, more treatable stages, progress has been limited. New methods and new instruments for analysis of differences in gene expression, gene methylation, and proteomics are being employed to try to accelerate the discovery phase. Given the heterogeneity of tumor mechanisms and the limitations of analytical methods, it is likely that a variety of strategies will be needed and will be complementary. That is the basis of this review of proteomic approaches. This article adopts a systems biology view, starting with mRNA transcripts in tumors and cultured tumor cells to detect mRNA overexpression, some of which will be correlated with protein overexpression. Some of those proteins may be secreted or released into proximal biofluids and plasma. Detection of low-abundance tumor proteins in the complex and dynamic mixture that is plasma requires combinations of increasingly powerful technologies. The biological amplification of protein signals through the immune system offers autoantibodies as potential biomarkers. Higher abundance proteins, including acute-phase reactants, may have practical value, especially if the proteins are modified as part of the cancer processes. Low molecular weight proteins, fragments, and peptides may offer complementary biomarkers. Promising biomarker candidates must be confirmed in independent studies. Then they must be submitted to higher-throughput methods practical for large-scale validation studies and, hopefully, for clinical and epidemiological applications. Standardized operating procedures for specimen handling, design and use of various reference standards, care to avoid bias and confounding, and guidelines for reporting findings and contributing datasets should enhance the prospects for predictive proteomic profiling of people at risk for cancers.

Biomarkers, Tumor↗
PubMed2000

Testicular volume in Japanese boys up to the age of 15 years.

UNLABELLED: Previous studies have indicated that Japanese children grow and mature significantly faster than Caucasian children, thus calling for a separate reference standard for each skeletal and sexual maturity index. To establish normal reference values for testicular volume in Japanese boys, we studied from 1985 to 1995, 900 healthy male children of 0 to 15 years of age for medical history, physical examination, height, weight, sitting height, and head circumference measurements, Tanner sex maturity stage, and testicular size. The testicular volume was determined using a Prader orchidometer by the same observer (N.M.). Based on these data, we established the cross-sectional percentile growth curves (90th, 50th, 10th percentiles) for testicular volume of Japanese boys. The testicular volume of 3 ml was attained at 9.3 years of age (90th percentile), 11.0 years of age (50th percentile), and 12.1 years of age (10th percentile), respectively. CONCLUSION: Swelling of the testis in Japanese children begins approximately 1 year earlier than in Swiss children in accordance with the earlier skeletal maturation in Japanese children.

Adolescent↗
PubMed1990

Immunochemical investigation of allergens from Rhizopus nigricans.

The allergenic proteins of mould, Rhizopus nigricans extract (RNE) were identified and characterized by crossed immunoelectrophoresis (CIE), thin-layer isoelectrofocusing (TLIEF) and RAST inhibition. CIE revealed that the extract contained at least 31 distinct antigens. On TLIEF the extract resolved into 22 bands in pI 3.5-6.8. Two important allergens, Rhiz IIIb and VIb were purified by a combination of ammonium sulfate precipitation, anion exchange chromatography on DEAE-Sephadex column and gel filtration. Twenty and 12 micrograms of Rhiz IIIb and Rhiz VIb were sufficient to give 50% RAST inhibition as against 43 micrograms of crude RNE. Rhiz IIIb and Rhiz VIb were found to be glycoproteins with molecular weights of 12,400 daltons and 14,200 daltons, respectively. Rhiz IIIb was found to be homogeneous on polyacrylamide gel electrophoresis (PAGE) and TLIEF with a pI of 4.8, while Rhiz VIb gave a single band on PAGE and resolved into two Coomassie blue stained bands with pI 3.6 and 3.8. It was possible to separate the components of RNE on fast protein liquid chromatography (FPLC) using an anion exchanger Mono Q column. The identification and characterization of the antigenic and allergenic proteins in the extract will be useful in standardization of RNE and in preparation of an in-house reference standard.

Allergens↗
PubMed2005

Plasmodium ovale: parasite and disease.

Humans are infected by four recognized species of malaria parasites. The last of these to be recognized and described is Plasmodium ovale. Like the other malaria parasites of primates, this parasite is only transmitted via the bites of infected Anopheles mosquitoes. The prepatent period in the human ranges from 12 to 20 days. Some forms in the liver have delayed development, and relapse may occur after periods of up to 4 years after infection. The developmental cycle in the blood lasts approximately 49 h. An examination of records from induced infections indicated that there were an average of 10.3 fever episodes of > or = 101 degrees F and 4.5 fever episodes of > or = 104 degrees F. Mean maximum parasite levels were 6,944/microl for sporozoite-induced infections and 7,310/microl for trophozoite-induced infections. Exoerythrocytic stages have been demonstrated in the liver of humans, chimpanzees, and Saimiri monkeys following injection of sporozoites. Many different Anopheles species have been shown to be susceptible to infection with P. ovale, including A. gambiae, A. atroparvus, A. dirus, A. freeborni, A. albimanus, A. quadrimaculatus, A. stephensi, A. maculatus, A. subpictus, and A. farauti. An enzyme-linked immunosorbent assay has been developed to detect mosquitoes infected with P. ovale using a monoclonal antibody directed against the circumsporozoite protein. Plasmodium ovale is primarily distributed throughout sub-Saharan Africa. It has also been reported from numerous islands in the western Pacific. In more recent years, there have been reports of its distribution on the Asian mainland. Whether or not it will become a major public health problem there remains to be seen. The diagnosis of P. ovale is based primarily on the characteristics of the blood stages and its differentiation from P. vivax. The sometimes elliptical shape of the infected erythrocyte is often diagnostic when combined with other, subtler differences in morphology. The advent of molecular techniques, primarily PCR, has made diagnostic confirmation possible. The development of techniques for the long-term frozen preservation of malaria parasites has allowed the development diagnostic reference standards for P. ovale. Infections in chimpanzees are used to provide reference and diagnostic material for serologic and molecular studies because this parasite has not been shown to develop in other nonhuman primates, nor has it adapted to in vitro culture. There is no evidence to suggest that P. ovale is closely related phylogenetically to any other of the primate malaria parasites that have been examined.

Animals↗
PubMed2006

Accuracy of stepping-table lower extremity MR angiography with dual-level bolus timing and separate calf acquisition: hybrid peripheral MR angiography.

PURPOSE: To retrospectively evaluate the accuracy of hybrid peripheral magnetic resonance (MR) angiography by using conventional digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: This retrospective study protocol received approval from the Office of Sponsored Research at Northwestern University, which included review by the Office for the Protection of Research Subjects. Informed consent was waived for this HIPAA-compliant study. One hundred twenty-one consecutive patients (67 men: mean age, 66 years +/- 12 [standard deviation]; 54 women: mean age, 69 years +/- 14), who were referred for evaluation of peripheral vascular disease, underwent peripheral contrast material-enhanced MR angiography. By using a hybrid technique, two independent timing measurements were performed in the pelvis and calves followed by MR angiography of the calves and, subsequently, a pelvis-thigh stepping-table acquisition. Images were evaluated for extent of disease, on the basis of degree of stenosis; for venous contamination, on the basis of venous signal intensity; and for diagnostic quality, on the basis of diagnostic confidence of the observer. DSA correlation of the extent of vascular disease was available in 45 of these patients, which was used to evaluate the diagnostic power of the hybrid technique. RESULTS: For detection of stenosis greater than 50%, the hybrid technique had 95% sensitivity (P < .05), 95% specificity (P < .05), and 95% accuracy (P < .05). There was no significant venous contamination in any of the examinations performed with this technique. CONCLUSION: The hybrid peripheral MR angiography technique provides diagnostic-quality examinations and virtually eliminates venous contamination.

Adult↗
PubMed2000

Colonic masses: detection with MR colonography.

PURPOSE: To assess magnetic resonance (MR) colonography as a method for detection of colorectal masses, with conventional colonoscopy as the reference standard. MATERIALS AND METHODS: MR colonography was performed in 132 patients referred for colonoscopy because of the possible presence of a mass. After rectal filling with a gadopentetate dimeglumine and water enema, T1-weighted three-dimensional gradient-echo MR studies were acquired with the patient in the prone and supine positions. Water-sensitive single-shot fast spin-echo MR images were also obtained. Surface-rendered virtual endoscopic endoluminal views, orthogonal sections in three planes, and water-sensitive MR images were interactively assessed for presence of colorectal masses by two radiologists. RESULTS: MR colonography was well tolerated without sedation or analgesia. MR image quality was sufficient for diagnosis in 127 (96%) patients. Most small (</=5-mm-diameter) masses were overlooked at MR colonography, but 19 of 31 6-10-mm lesions and 26 of 27 large (>10-mm) lesions were correctly identified. For these large masses, MR colonography had a sensitivity of 93%, specificity of 99%, positive predictive value of 92%, and negative predictive value of 98% for detection of masses. CONCLUSION: MR colonography is a promising modality for help in detecting colorectal mass lesions larger than 10 mm in diameter.

Administration, Rectal↗
PubMed2001

Determination of beryllium and selenium in human urine and of selenium in human serum by graphite-furnace atomic absorption spectrophotometry.

For human urine beryllium (Be), each sample (500 microl) was diluted (1+1) with Nash reagent (containing 0.2% (v/v) acetylacetone and 2.0 M ammonium acetate buffer at pH 6.0) and then a 20-microl volume of Triton X-100 (0.4%, v/v) aqueous solution was added. An aliquot (10 microl) of the diluted urine mixture was introduced into a graphite cuvette and was atomized according to a temperature program. The method detection limit (MDL, 3sigma) for Be was 0.37 microg/l in the undiluted urine sample and the calibration graph was linear up to 65.0 microg/l. Calibration graphs were prepared by the standard addition method. Accuracies of 98.6-102% were obtained when testing standard reference material (SRM 2670) freeze dried human urine samples. Precision (relative standard deviation, RSD) for urine Be was < or = 2.3% (withinrun, n = 5) and was < or = 3.0% (between-run, n = 3). For human urine and serum selenium (Se), samples (100 microl) were diluted with HNO3 (0.2%, v/v) to make a (1+1) dilution for urine analysis or a (1+4) dilution for serum analysis. An additional aliquot (10 microl) of Triton X-100 (0.1%, v/v) was added to each 200 microl of (1+1) diluted urine (or 20 microl of the Triton X-100 was added to each 500 microl of (1+4) diluted serum) sample. After the diluted sample mixture (10 microl) was introduced into a graphite cuvette, the corresponding chemical modifier (10 microl, containing Ni2+ + Pd + NH4NO3 in HNO3 (0.2%, v/v)) was added to it and the mixture was atomized. The MDL (3sigma) for Se in urine and in serum was 4.4 and 21.4 microg/l in undiluted sample, respectively, and the calibration graphs were linear up to 150 and 400 microg/l. Accuracies of urine Se were 98.9 - 99.4% by testing SRM 2670 (NIST) urine standards with RSD (between-run, n = 3) within 2.9%; and that of serum Se was 97.2% when testing a certified second-generation human serum (No. 29, #664) with RSD (between-run, n = 3) of 1.4%. The proposed method can be applied easily, directly, and accurately to the measurement of Be and Se in real samples (including six urine Se and four serum Se from patients of Blackfoot Disease in Taiwan).

Beryllium↗