The Open Clinical Chemistry Journal最新文献

{"title":"Inhibition of Horseradish Peroxidase (HRP) by a Nonhydrophobic Component of Urine: A Caution for Immunoassays","authors":"K. Campbell, M. LoPresti, W. Lukas","doi":"10.2174/1874241601407010001","DOIUrl":"https://doi.org/10.2174/1874241601407010001","url":null,"abstract":"Undiluted urine mixed directly with HRP suppresses generation of enzyme product to less than 80% of that seen in buffer controls. Incubating dilutions of various urine preparations with HRP immobilized on concanavalin A coated microtiter plates reveals that the source of urine or HRP, and the type of HRP substrate used have minimal effect on the degree of HRP suppression; only dilutions of urine greater than 8-fold with buffer produce HRP activities equivalent to those in buffer. Treating urine with charcoal or C18 silica only partially reverses the HRP suppression. Inhibition of HRP in competitive assays biases results to the high side and in noncompetive assays biases results to the low side. The present findings suggest analysts should avoid immunoassay protocols that allow direct contact between undiluted urine and HRP reporter conjugates and should be cautious with quantitative results previously reported from assays that used undiluted urine with HRP reporters.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124778764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of a Novel Polyclonal Antibody-Based Immunoassay for the Quantitation of Non-Albumin Urinary Proteins","authors":"W. Haigh, D. Guralski, L. Arrigo, J. Letsinger, Michele V. Clarke, R. MacIsaac, G. Jerums, D. L. Very","doi":"10.2174/1874241601306010001","DOIUrl":"https://doi.org/10.2174/1874241601306010001","url":null,"abstract":"Background:\u0000 Better diagnostic methods to detect urinary proteinuria or albuminuria, important indicators of\u0000diabetic kidney disease, are needed. Here, we describe the development and performance qualification of a new immunoassay\u0000for the quantitation of non-albumin urinary proteins of 20 to 90 kilodaltons.\u0000 Methods:\u0000 Urinary proteins, purified from pooled, 24-hour, diabetic urines, were immunoabsorbed to remove albumin,\u0000electrophoretically characterized, and identified by mass spectrometry. Sheep anti-urinary protein polyclonal antibodies\u0000were immunoabsorbed to remove albumin reactivity. Major immunoreactive specificities of the polyclonal antibody were\u0000identified by Western blot. A polyclonal antibody-based competitive immunoassay was developed and performanceevaluated.\u0000An unpaired t-test (α = 0.05) and a receiver-operating characteristic curve were used to evaluate the measurement\u0000of 24-hour urinary protein excretion rates in distinguishing between normal, proteinuric, and albuminuric samples.\u0000 Results:\u0000 Approximately 380 mg of urinary protein was purified from 6.0 g of total urinary proteins. Mass spectrometry\u0000identified more than 36 different proteins in the purified preparation. The anti-urinary protein polyclonal antibody possessed\u0000significant immunoreactivity towards transferrin, IgG chains, alpha-1-acid glycoprotein, zinc-alpha-2-glycoprotein,\u0000prostaglandin-H2-d-isomerase, and alpha-1-microglobulin. The competitive immunoassay exhibited excellent analytical\u0000and clinical performance. Measurement of urinary protein excretion rates could distinguish between normoproteinuric and\u0000proteinuric samples (p < 0.0001; area under the curve = 0.6900) and between normoalbuminuric and albuminuric samples\u0000(p < 0.0001; area under the curve = 0.8782).\u0000 Conclusion:\u0000 Measurement of urinary protein excretion rates using the urinary protein immunoassay is clinically equivalent\u0000to laboratory methods of quantitating total urinary protein or albumin in identifying proteinuria and albuminuria.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125741797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Calibrators for Clinical Measurements of Phosphorylated H2AX in Patient Cells by Flow Cytometry","authors":"Aida Muslimović, P. Johansson, U. Rüetschi, O. Hammarsten","doi":"10.2174/1874241601205010033","DOIUrl":"https://doi.org/10.2174/1874241601205010033","url":null,"abstract":"Agents that induce DNA double-strand breaks (DSBs), such as ionizing radiation, are frequently used in cancer therapy. H2AX is rapidly phosphorylated in response to DSBs and serves as a way to measure the extent of DSBs induced in patient cells. We have previously reported a flow cytometry-based method for measuring H2AX phosphorylation in pa- tient cells undergoing radiotherapy. To be able to implement measurement of H2AX phosphorylation in clinical practice, we have characterized calibrators for the flow cytometry analysis based on phosphopeptide-coated beads and fixed cells. The calibrator beads and fixed cells lost less than 11% of the signal after storage for 40 days under optimal conditions and were able to correct for day-to-day variation in method performance.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133044003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of a Sensitive Copeptin Assay for Clinical Measurement","authors":"D. Terzic, A. S. Johansson-Fällgren, O. Ragnarsson, J. Goetze, O. Hammarsten","doi":"10.2174/1874241601205010021","DOIUrl":"https://doi.org/10.2174/1874241601205010021","url":null,"abstract":"Background: Copeptin, a marker of vasopressin production, has been introduced for earlier diagnosis of acute myocardial infarction and other clinical emergencies. We evaluated the analytical performance of a new generation co- peptin assay in an inter-laboratory trial. Methods: Precision, linearity range, carry-over contamination, the limit of blank and an inter-laboratory comparison trial for the copeptin US KRYPTOR assay were performed on the B·R·A·H·M·S KRYPTOR compact PLUS. Results: The intra-assay imprecision (CVs) was 12.6-2.2% and total imprecision over five days was 12.3-4.3% between 3.1 and 18.2 pmol/L. The assay had excellent linearity between 7-222 pmol/L. The limit of blank was 2.5 pmol/L and the limit of detection was 3.2 pmol/L, but was dependent on the analyte-free material used. No significant difference between sample type, such as serum or different types of plasma or reagent lots, was noted. The copeptin results remained un- changed upon five repeated freeze-thaw cycles. A set of patient samples with a mean copeptin concentration of 2.1-61 pmol/L run at two separate sites showed close correlation (r 2 =0.99, slope=1.01, intercept=0.35), indicating comparable re- sults across laboratories. Conclusion: The new ultrasensitive copeptin KRYPTOR assay shows excellent inter-lab precision, opening up the possi- bility for international guidelines to exclude acute myocardial infarction.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"486 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133045217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paradoxes and Pitfalls of Interleukin-33 in Atherosclerosis","authors":"P. Kuneš, Z. Holubcová, M. Kolácková, J. Krejsek","doi":"10.2174/1874241601205010013","DOIUrl":"https://doi.org/10.2174/1874241601205010013","url":null,"abstract":"Atherosclerosis is definitely considered as an inflammatory/immunopathological disease. The long-standing low-grade inflammation is focused on the components of the vessel wall. Initially, this inflammation was assumed to be driven by the pro-inflammatory Th1 cellular and cytokine immune responses. On the basis of accumulating knowledge, however, this view has been specified to include the Th17/Th1 axis which underlies most immunopathological diseases accompanied by sterile inflammation. On the other hand, an anti-inflammatory Th2 cellular and cytokine immune re- sponse attempts to dampen these unfavorable reactions which terminate in full-blown atherosclerosis. Interleukin-33, the novel member of the IL-1 cytokine superfamily, was suggested to take part in the anti-atherogenic response by mediating the Th1-to-Th2 switch of the immune reactions. However, IL-33 is a multifaceted mediator with both pro- and anti- inflammatory activities. IL-33 presents both an extracellular (cytokine-like) and a nuclear-bound (transcription factor-like) form, each of them performing distinct activities of their own. This review article summarizes latest data relevant to IL- 33´s role in atherosclerosis, underscoring the paradoxes and pitfalls of laboratory findings and their extrapolation to live organisms including humans.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117039409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Serum Levels of Mature Brain-Derived Neurotrophic Factor (BDNF) and Its Precursor proBDNF in Healthy Subjects","authors":"Taisuke Yoshida, Masatomo Ishikawa, M. Iyo, K. Hashimoto","doi":"10.2174/1874241601205010007","DOIUrl":"https://doi.org/10.2174/1874241601205010007","url":null,"abstract":"BACKGROUND: Accumulating evidence points to the brain-derived neurotrophic factor (BDNF) as a bio- marker for neuropsychiatric diseases, such as major depression. Mature BDNF is synthesized from its precursor form, proBDNF. Although BDNF levels in human blood can be measured using commercially available human BDNF ELISA kits, due to limited specificity of the BDNF antibody, these kits are unable to distinguish between proBDNF and mature BDNF. In this study, we measured serum levels of proBDNF and mature BDNF in healthy subjects, using human proBDNF and BDNF ELISA kits, respectively. METHODS: Serum levels of proBDNF and mature BDNF in healthy subjects (n = 40) were measured using the sand- wich human proBDNF and BDNF ELISA kits. RESULTS: In healthy subjects, serum levels of mature BDNF were 23.71 ± 5.61 ng/mL (mean ± S.D., n=40). Serum levels of proBDNF in healthy subjects were 7.58 ± 7.68 ng/mL (mean ± S.D., n=25). However in 15 subjects, serum lev- els of proBDNF were less than the minimum detectable concentration (0.5 ng/mL) of the kit. CONCLUSIONS: This study shows that serum levels of proBDNF and mature BDNF are measurable using either the commercially available human proBDNF or BDNF ELISA kits, although the sensitivity of proBDNF kit was unaccepta- bly low. These ELISA kits may be useful for measuring proBDNF and mature BDNF in the body fluids of patients with neuropsychiatric, cardiovascular and other diseases.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"8 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113931394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of the Inhibition of Mitochondrial Creatine Kinase Activity on the Clinical Diagnosis of Suspected Acute Myocardial Infarction","authors":"M. Maekawa, Aya Sugiura, K. Iwahara, Y. Sakai, Kouji Kishi","doi":"10.2174/1874241601205010001","DOIUrl":"https://doi.org/10.2174/1874241601205010001","url":null,"abstract":"Background: Creatine kinase isoenzyme MB (CK-MB) activity using the immunoinhibition method has been measured in clinical laboratories. However, the presence of mitochondrial CK (MtCK) abnormally increases CK-MB ac- tivity when measured using the conventional method, which can lead to misdiagnosis of acute myocardial infarction (AMI). A new CK-MB activity assay kit that can inhibit MtCK activity was recently developed; here, we describe the per- formance of this kit. Methods: The analytical performance of this new kit was investigated using 338 samples, and the correlation between re- sults obtained using the new and conventional kits were analyzed. Results: A good correlation (r > 0.993) was found between results obtained using the new and conventional kits in the sera from patients with obvious AMI (n = 91). However, a poor correlation exists between results obtained using the new and conventional kits in samples from patients without AMI. Electrophoretic CK isoenzyme analysis confirmed that the ap- pearance of MtCK in nearly all samples from patients with malignant tumors makes poor correlation. Conclusion: Inhibiting MtCK activity is important for diagnosing AMI. The new method may provide a more accurate value of CK-MB activity for clinical use.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114502665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comparison of Two Immunoassays for Analysing Plasma 25-hydroxyvitamin D","authors":"K. Sarafin, N. Hidiroglou, S. Brooks","doi":"10.2174/1874241601104010045","DOIUrl":"https://doi.org/10.2174/1874241601104010045","url":null,"abstract":"A total of 1628 human plasma samples from Cycle 1 of the Canadian Health Measures Survey were assayed for total 25-hydroxyvitamin D using the DiaSorin RIA method and the Diasorin \"LIAISON 25 OH Vitamin D Total\" method. Bland-Altman comparison showed an average bias of 4.8 ± 16.7 nmol/L (6.3%: P<0.001) with the LIAISON method giv- ing higher values. The relationship was investigated using linear and Deming regression. Linear regression gave: LIAISON = RIA*(0.87 ± 0.02) + (13.3 ± 1.2) (mean ± SE) and weighted Deming regression (constant CV) gave: LIAISON = RIA*(1.14 ± 0.02) - (4.2 ± 1.2). The significant deviations from a slope of unity and the significant non-zero intercepts were further investigated using non-linear regression. Quadratic regression gave: LIAISON = RIA 2 * (-0.0025 ± 0.0005) + RIA*(1.211 ± 0.07) + (2.9 ± 2.5). The intercept was not significantly different from 0. The quadratic equation significantly decreased the residual sum of squares (P<0.0001) indicating this model better described the relationship. Non-linearity was apparent at RIA 25-hydroxyvitamin D � 110 nmol/L, where the relationship was described by: LIAISON = 97.5339 + 0.1388*RIA (r 2 = 0.0039; N.S.). However, removing points RIA � 110 nmol/L did not substan- tially alter the regression parameters. Comparing the analytical imprecision with the total random regression error (Sy/x) suggested that sample-related effects were not present. It is recommended that cross-over analysis between these two methods include points from all parts of the range of interest to elucidate the complete nature of the relationship.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130369924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Oxidative Stress of Hyperhomocysteinemia Results from Reduced Bioavailability of Sulfur-Containing Reductants","authors":"Y. Ingenbleek","doi":"10.2174/1874241601104010034","DOIUrl":"https://doi.org/10.2174/1874241601104010034","url":null,"abstract":"Vegetarian subjects consuming subnormal amounts of methionine (Met) are characterized by subclinical pro- tein malnutrition causing reduction in size of their lean body mass (LBM) best identified by the serial measurement of plasma transthyretin (TTR). As a result, the transsulfuration pathway is depressed at cystathionine-� -synthase (CS) level triggering the upstream sequestration of homocysteine (Hcy) in biological fluids and promoting its conversion to Met. Maintenance of beneficial Met homeostasis is counterpoised by the drop of cysteine (Cys) and glutathione (GSH) values downstream to CS causing in turn declining generation of hydrogen sulfide (H2S) from enzymatic sources. The biogene- sis of H2S via non-enzymatic reduction is further inhibited in areas where earth's crust is depleted in elemental sulfur (S8) and sulfate oxyanions. Combination of subclinical malnutrition and S8-deficiency thus maximizes the defective produc- tion of Cys, GSH and H2S reductants, explaining persistence of unabated oxidative burden. The clinical entity increases the risk of developing cardiovascular diseases (CVD) and stroke in underprivileged plant-eating populations regardless of Framingham criteria and vitamin-B status. Although unrecognized up to now, the nutritional disorder is one of the com- monest worldwide, reaching top prevalence in populated regions of Southeastern Asia. Increased risk of hyperhomocys- teinemia and oxidative stress may also affect individuals suffering from intestinal malabsorption or westernized communi- ties having adopted vegan dietary lifestyles.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129340869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Decreased Levels of Serum Brain-Derived Neurotrophic Factor in Male Pediatric Patients with Depression","authors":"Tsuyoshi Sasaki, T. Niitsu, T. Hashimoto, N. Kanahara, A. Shiina, T. Hasegawa, H. Kimura, M. Ishikawa, Junko Tone, A. Yamauchi, Yutaka Hosoda, M. Kunou, Junpei Takahashi, T. Ishima, Yuko Fujita, M. Nakazato, K. Hashimoto, M. Iyo","doi":"10.2174/1874241601104010028","DOIUrl":"https://doi.org/10.2174/1874241601104010028","url":null,"abstract":"Background: Brain-derived neurotrophic factor (BDNF) plays an important role in the pathophysiology of ma- jor depressive disorder (MDD). Several meta-analyses have shown decreased serum levels of BDNF in adult patients with MDD, but there has been no report on the serum levels of BDNF in pediatric patients with depression. In this study, we investigated whether serum levels of BDNF are altered in pediatric patients with depression. Methods: We measured serum BDNF levels in the following four groups: male pediatric patients with depression (n = 13), female pediatric patients with depression (n = 17), and age-matched normal control subjects (n = 10 for Male, n=12 for Female). Patients were evaluated using the Children's Depression Rating Scale Revised (CDRS-R). Serum levels of BDNF were measured with the sandwich ELISA method. Results: Serum levels (6.97 ± 3.69 ng/mL (mean ± SD)) of BDNF in male pediatric patients with depression were signifi- cantly (p=0.019) lower than those (10.67 ± 3.11 ng/mL) in the male control group. However, there was no difference be- tween the female pediatric patients with depression (9.29 ± 4.61 ng/mL) and the female control group (10.21 ± 4.79 ng/mL). Furthermore, there was no correlation between serum levels of BDNF and CDRS-R scores in the pediatric pa- tients with depression. Interestingly, there was a significant negative correlation (r = -0.683, p=0.010) between the serum BDNF levels and the duration of illness in male, but not female, pediatric patients with depression. Conclusions: This study suggests that low BDNF levels may play a role in the pathophysiology of male pediatric patients with depression.","PeriodicalId":112973,"journal":{"name":"The Open Clinical Chemistry Journal","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2011-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129513238","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}