Evaluation of the Abbott Investigational Use Only RealTime Hepatitis C Virus (HCV) Assay and Comparison to the Roche TaqMan HCV Analyte-Specific Reagent Assay

The accurate and sensitive measurement of hepatitis C virus (HCV) RNA is essential for the clinical management and treatment of infected patients and as a research tool for studying the biology of HCV infection. We evaluated the linearity, reproducibility, precision, limit of detection, and concordance of viral genotype quantitation of the Abbott investigational use only RealTime HCV (RealTime) assay using the Abbott m2000 platform and compared the results to those of the Roche TaqMan Analyte-Specific Reagent (TaqMan) and Bayer Versant HCV bDNA 3.0 assay. Comparison of 216 samples analyzed by RealTime and TaqMan assays produced the following Deming regression equation: RealTime = 0.940 (TaqMan) + 0.175 log₁₀ HCV RNA IU/ml. The average difference between the assays was 0.143 log₁₀ RNA IU/ml and was consistent across RealTime''s dynamic range of nearly 7 log₁₀ HCV RNA IU/ml. There was no significant difference between genotypes among these samples. The limit of detection using eight replicates of the World Health Organization HCV standard was determined to be 7.74 HCV RNA IU/ml by probit analysis. Replicate measurements of commercial genotype panels were significantly higher than TaqMan measurements for most samples and showed that the RealTime assay is able to detect all genotypes with no bias. Additionally, we showed that the amplicon generated by the widely used Roche COBAS Amplicor Hepatitis C Virus Test, version 2.0, can act as a template in the RealTime assay, but potential cross-contamination could be mitigated by treatment with uracil-N-glycosylase. In conclusion, the RealTime assay accurately measured HCV viral loads over a broad dynamic range, with no significant genotype bias.Methods for accurate quantitation of serum and plasma hepatitis C virus (HCV) RNA levels have become key tools both for understanding the biology of HCV infection and for the clinical management of patients under treatment. The ability to predict likelihood of response to combination interferon/ribavirin therapy by assessing rates of HCV viral load decline has provided a more individualized treatment algorithm that can identify nonresponsive patients early in treatment, sparing them significant morbidity and cost. New algorithms that examine the kinetics of HCV viral decline provide an even more refined tool for management and complement the information provided by HCV genotype determination. Finally, HCV viral kinetics data are essential for the understanding of new therapeutics such as the class of protease inhibitors. For all applications, accurate quantitation of all HCV types over a broad dynamic range is critical. The advent of real-time PCR methods provides a powerful tool for a broad dynamic range of quantitation of viruses; however, targets such as HCV require careful assay design to avoid errors due to sequence variations intrinsic to RNA viruses.Abbott Molecular, Inc. (Des Plaines, IL), recently released the m2000 system and tests for human immunodeficiency virus type 1, HCV, and chlamydia/gonorrhea (Chlamydia trachomatis/Neisseria gonorrhea) in the European Union with Conformité Européene-marked certification, and the system was recently approved for human immunodeficiency virus type 1 by the U.S. Food and Drug Administration. The m2000 system consists of an eight-channel liquid handling platform (the m2000sp) for performing automated nucleic acid extraction and PCR preparation and of a real-time PCR platform (the m2000rt) for detection and quantification. We used the m2000 system to evaluate the sensitivity, reproducibility, linearity, and concordance of viral genotype quantitation of the Abbott Molecular investigational use only (IUO) RealTime HCV (RealTime) assay and compared aspects of its performance to the Roche TaqMan Analyte-Specific Reagent (ASR) (TaqMan) (Roche Molecular Systems, Inc., Branchburg, NJ) and Bayer Versant HCV bDNA 3.0 (bDNA) assay. In addition, we examined the potential for contamination by the Roche COBAS Amplicor Hepatitis C Virus Test, version 2.0 (Amplicor) (Roche Molecular Systems, Inc., Branchburg, NJ) and TaqMan amplicons and the effect of uracil-N-glycosylase (UNG) treatment in mitigating contamination from these widely used tests.     

Performance characteristics of the COBAS Amplicor Hepatitis C Virus (HCV) Monitor, Version 2.0, International Unit assay and the National Genetics Institute HCV Superquant assay

The COBAS Amplicor Hepatitis C Virus (HCV) Monitor assay, version 2.0, which reports in international units per milliliter, was compared to the assay reported in copies per milliliter by analyzing dilution series and clinical plasma samples by both methods. In addition, the Amplicor international unit assay was compared to the National Genetics Institute HCV Superquant assay. The dilution series ranged from <100 to 5,000,000 HCV RNA copies/ml and consisted of 32 points, assayed in triplicate in each assay. Thirty clinical samples ranging from 1,000 to 1,000,000 HCV RNA copies/ml were assayed in duplicate. Deming regression analysis comparing the Amplicor HCV RNA international units-per-milliliter and copies-per-milliliter assays was calculated as follows: (Amplicor international units per milliliter) = 1.030(Amplicor copies per milliliter) - 0.392; R(2) = 0.981; n = 28; S(y/x) (standard error of the estimate) = 0.129. The linearity of the Amplicor international units-per-milliliter assay was as follows: observed = 0.886(expected) + 0.437; R(2) = 0.983; n = 30. The linearity of the Superquant assay was as follows: observed= 0.918 (expected) + 0.436; R(2) = 0.986; n = 32. Deming regression analysis comparing the Amplicor and Superquant assays was calculated as follows: Superquant = 1.066(Amplicor) - 0.0197; R(2) = 0.908; S(y/x) = 0.308; n = 28. The Amplicor and Superquant assays were linear through the range of 600 to 600,000 IU of HCV RNA/ml and approximately 300 to 5,000,000 HCV RNA copies/ml, respectively. The narrow range of the Amplicor assay means that some samples will require dilution and retesting for accurate quantification above 600,000 IU of HCV RNA/ml. The Amplicor and Superquant assays agreed well within the range of 600 to 600,000 IU of HCV RNA/ml (approximately 1,000 to approximately 1,000,000 HCV RNA copies/ml). Overall, the Amplicor and Superquant assays agree well, and results obtained in one assay could be expected to compare well with results from the other when reported in copies per milliliter.     

Prevalence of IgG autoantibody against F-actin in patients suspected of having autoimmune or acute viral hepatitis

Our objectives in this study were to compare results obtained by an enzyme immunoassay (EIA) for F-actin antibody (FAA) immunoglobulin G (IgG) to those determined by an indirect fluorescent antibody (IFA) assay for smooth muscle antibody (SMA) IgG, and to determine the prevalence of FAA in patient sera having serologic evidence of acute viral hepatitis. Sera from 415 patients suspected of having autoimmune hepatitis (AIH), 208 patients suspected of having acute viral hepatitis A, B, or C, and 100 healthy blood donors (HBD) were included in the study. Only one of 100 HBD showed low levels (20-30 Units) of F-actin IgG. In patients suspected of having AIH, the prevalence of FAA increased as SMA titers increased and all sera with SMA titers of >or=1:160 were FAA-positive. In contrast, there were many sera with negative (<1:20) or low (1:20-1:40) SMA titers that contained moderate to high levels (>30 Units) of FAA; many exceeding 80 Units. Moreover, 51.4% of these sera were also positive for anti-nuclear antibody (ANA), which is also utilized in diagnosing type 1 AIH. FAA was detected in 25% of viral hepatitis antibody-positive sera, with the majority (59.3%) containing low levels, and all were ANA-negative.     

Economic burden of comorbidities in patients with psoriasis is substantial

Background Psoriasis is frequently associated with comorbidities. Objective To estimate the incremental economic burden associated with comorbidities in patients with psoriasis, accounting for psoriasis severity. Methods Patients continuously enrolled ≥ 6 months after a randomly selected psoriasis diagnosis date were selected from the Ingenix Impact National Managed Care Database (1999–2004). Comorbidities identified during the 6‐month study included: psoriatic arthritis, cardiovascular disease, depression, diabetes, hyperlipidemia, hypertension, obesity, cerebrovascular diseases and peripheral vascular disease. Resource utilization and costs during the 6‐month follow‐up period were compared for patients with ≥ 1 comorbidity vs. those without and for patients with a specific comorbidity vs. those without. Adjusted incidence rate ratios (IRRs) and odds ratios (ORs) were estimated for resource utilization using negative binomial and logistic regression models, respectively. Adjusted incremental costs associated with comorbidities were reported using general linear models with log‐link and gamma distributions or two‐part models. Models controlled for age, sex and psoriasis severity. Results A total of 114 512 patients were included; 51% had ≥ 1 comorbidity. Hyperlipidemia (27%) and hypertension (25%) were most prevalent. Patients with comorbidities were more likely to experience urgent care [OR (95% confidence interval (CI)) = 1.58 (1.51–1.65)] than patients without comorbidities. They also had significantly greater hospitalization rates [IRR (95% CI) = 2.27 (2.13–2.42)] and outpatient visits [IRR (95% CI) = 1.53 (1.52–1.55)]. Compared with patients who did not have comorbidities, patients with comorbidities incurred $2184 (P < 0.001) greater total costs. Conclusion Comorbidities present a significant economic burden in patients with psoriasis.     

白三烯拮抗剂ONO-1078对化学物质诱导大鼠皮肤微血管渗漏的抑制作用

大鼠皮内注射组胺、辣椒素和甲醛诱导皮肤微血管渗漏,白三烯拮抗剂ONO-1078剂量依赖性抑制这一反应,ID₅₀分别为1.98,1.78,2.23mg·kg^-1。与扑尔敏相比,对组胺的作用较弱,对辣椒素和甲醛的作用较强,地塞米松的作用强于ONOl078和扑尔敏。ONO-l078还抑制LTD4的作用,对大剂量组胺、缓激肽和P物质无明显作用。ONO-l078的作用可能与抑制感觉神经肽释放有关。     

速激肽NK-1受体拮抗剂SR-140333对抗原引起致敏大鼠气道高反应性的影响

为观察速激肽NK-1受体拮抗剂SR-140333对抗原攻击引起的致敏大鼠气道高反应性的影响,测定了致敏大鼠在抗原攻击前后的基础呼吸频率,对MCh的反应性及支气管-肺泡灌洗液中的白细胞数量。实验结果显示,致敏大鼠吸入OA后6h基础呼吸频率增加,并显著增加乙酰甲胆碱(MCh)的反应性、MCh的-logPC₃₀值和支气管-肺泡灌洗液中的白细胞数量。ip速激肽NK-1受体拮抗剂SR-140333(0.1mg·kg^-1)或地塞米松(0.5mg·kg^-1),可明显抑制上述反应,小剂量SR-140333(0.01mg·kg^-1)仅有部分抑制作用。结果提示抗原攻击可引起致敏大鼠气道高反应性和气道炎症,速激肽NK-1受体拮抗剂可抑制这些反应。     

速激肽NK-1受体拮抗剂SR-140333对抗原引起致敏大鼠气道高反应性的影响

为观察速激肽ＮＫ１受体拮抗剂ＳＲ１４０３３３对抗原攻击引起的致敏大鼠气道高反应性的影响，测定了致敏大鼠在抗原攻击前后的基础呼吸频率，对ＭＣｈ的反应性及支气管肺泡灌洗液中的白细胞数量。实验结果显示，致敏大鼠吸入ＯＡ后６ｈ基础呼吸频率增加，并显著增加乙酰甲胆碱（ＭＣｈ）的反应性、ＭＣｈ的－ｌｏｇＰＣ３０值和支气管肺泡灌洗液中的白细胞数量。ｉｐ速激肽ＮＫ１受体拮抗剂ＳＲ１４０３３３（０１ｍｇ·ｋｇ－１）或地塞米松（０５ｍｇ·ｋｇ－１），可明显抑制上述反应，小剂量ＳＲ１４０３３３（００１ｍｇ·ｋｇ－１）仅有部分抑制作用。结果提示抗原攻击可引起致敏大鼠气道高反应性和气道炎症，速激肽ＮＫ１受体拮抗剂可抑制这些反应