Aortic valve replacement after previous coronary artery bypass grafting: a case report.

We experienced a case of aortic valve replacement after previous coronary artery bypass grafting with patent bypass grafts. Based on the retrosternal anatomy assessed by preoperative angiography and thoracic computed tomography, aortic valve replacement was performed through a median resternotomy. After careful dissection of the right side of the heart and the ascending aorta, cardiopulmonary bypass was established with cannulation of the ascending aorta and bicaval venous cannulation. The patent bypass grafts were dissected only as required for clamping and were clamped during cardiac arrest. After aortic valve replacement, the patient was uneventfully weaned from cardiopulmonary bypass and had a good postoperative recovery. It is important that surgeons have a meticulous strategy for reducing the risks associated with operating on patients with patent bypass grafts. We report on the surgical management of patients undergoing aortic valve replacement after previous coronary artery bypass grafting, including careful planning during the first operation.

[Evaluation of high-sensitivity HBsAg quantitative assay for HBV genotype].

The clinical implication of the hepatitis B surface antigen (HBsAg) concentrations has been reported in HBV-infected patients during anti-viral treatment. HBV genotypes A and D are ubiquitous and scattered worldwide, especially northern America as well as Europe, whereas genotypes B and C are common in Asia. The aim of this study was to evaluate a new version of the Sysmex HBsAg quantitative kit based on Chemiluminescence Enzyme Immunoassay. Sera collected from 172 patients infected with any of the four major genotypes A to D (HBV/A, n = 18; B, n = 25; C, n = 84; D, n = 45), including the genotype D cases with weak reaction in the previous version of the kit. The new version of the kit having additional monoclonal antibody, showed improved sensitivity compared to the previous version as well as robust correlation with another quantitative HBsAg assay: the Abbot Architect. Observed during lamivudine therapy, increase in HBsAg and HBV DNA concentrations preceded the aminotransferase (ALT) elevation associated with drug-resistant HBV variant emergence (breakthrough hepatitis). In conclusion, reliability of the Sysmex HBsAg quantitative assay was confirmed for the four HBV genotypes common worldwide. Monitoring of serum HBsAg concentrations in addition to HBV DNA quantification, is helpful in evaluation of the response or resistance to anti-viral therapy.

[Evaluation of serum PIVKA-II by Lumipulse PrestoII assay].

Measurements of serum concentrations of Des-gamma-carboxy Prothrombin (PIVKA-II) are widely used for diagnosing hepatocellular carcinoma (HCC). Recently, in Lumipulsef assay, it was reported that antibodies against alkaline phosphatase (ALP) derived from anti bleeding sheets led false high values of PIVKA-II in the patients with HCC resection. To improve the previous issue, newly developed Lumipulse PrestoII assay was examined. (1) The assay was reliable and positively correlated with the previous assays (Lumipulse f and Picolumi, R = 0.997 and 0.994 (n=115), respectively). (2) Eleven cases, which had false high values of PIVKA-II by the Lumipulsef assay, were examined by the PrestoII assay with excess of inactive ALP. The false high values of 10 cases were improved, but only one was still high. False reactivity of this case was stronger than other cases, more effective adsorption was required. (3) Comparing the absorbent activity of inactive ALP among 6 different kinds, we found inactive ALP with much higher adsorbent activity. When this inactive ALP was applied to assay, false high values of PIVKA-II were improved in all 11 cases. In conclusion, the PrestoII assay, which applies the inactive ALP with high activity, is reliable and useful for clinical screening.

[Evaluation of hepatitis B virus genotyping EIA kit].

Clinical significance of Hepatitis B virus(HBV) genotyping is increasingly recognized. The aim of this study was to evaluate reproducibility, accuracy, and sensitivity of an enzyme immunoassay (EIA) based HBV genotyping kit, which designed to discriminate between genotypes to A, B, C, or D by detecting genotype-specific epitopes in PreS2 region. Using the four genotypes panels, the EIA demonstrated complete inter and intra-assay genotyping reproducibility. Serum specimens had stable results after 8 days at 4 degrees C, or 10 cycles of freezing-thawing. In 91 samples that have been genotyped by DNA sequencing, 87(95.6%) were in complete accordance with EIA genotyping. Of examined 344 HBsAg-positive serum specimens, genotypes A, B, C and D were determined in 26 (7.6%), 62 (18.0%), 228 (66.3%), and 9 (2.6%) cases, respectively. Of 19 (5.5%) specimens unclassified by the EIA, 13 were found to have low titer of HBsAg concentration (< 3 IU/ml), and the other 5 had amino acid mutations or deletions within targeted PreS2 epitopes. The EIA allowed genotyping even in HBV DNA negative samples (96.2%). In conclusion, HBV genotype EIA is reliable, sensitive and easy assay for HBV genotyping. The assay would be useful for clinical use.

[Predicting sustained virological response in chronic hepatitis C patients treated with pegylated interferon and ribavirin using a novel highly sensitive Real-time detection PCR assay].

The Abbott Real Time HCV assay (lower limit of detection 12 IU/ml) was developed as a highly sensitive HCV RNA quantitative assay using real-time detection PCR(RTD-PCR). We assessed whether the new assay more effectively predicts sustained virological response (SVR) than conventional PCR (PCR) in 38 chronic hepatitis patients infected with HCV genotype 1b and treated with pegylated interferon alpha2b plus ribavirin. Sixteen patients reached SVR, 10 patients relapsed, 9 patients did not respond, 3 patients discontinued treatment. Positive predictive value (PPV) for SVR of undetectable HCV RNA at W4, 8, 12 by RTD-PCR and PCR was (100% vs. 100% at W4), (100% vs. 100% at W8), (83.3% vs. 72.7% at W12). HCV RNA undetectable at W12 had a higher PPV for SVR when measured by RTD-PCR than by conventional PCR.

[Clinical evaluation of a novel HBsAg quantitative assay].

The clinical implication of the hepatitis B surface antigen (HBsAg) concentrations in HBV-infected individuals remains unclear. The aim of this study was to evaluate a novel fully automated Chemiluminescence Enzyme Immunoassay (Sysmex HBsAg quantitative assay) by comparative measurements of the reference serum samples versus two independent commercial assays (Lumipulse f or Architect HBsAg QT). Furthermore, clinical usefulness was assessed for monitoring of the serum HBsAg levels during antiviral therapy. A dilution test using 5 reference-serum samples showed linear correlation curve in range from 0.03 to 2,360 IU/ml. The HBsAg was measured in total of 400 serum samples and 99.8% had consistent results between Sysmex and Lumipulse f. Additionally, a positive linear correlation was observed between Sysmex and Architect. To compare the Architect and Sysmex, both methods were applied to quantify the HBsAg in serum samples with different HBV genotypes/subgenotypes, as well as in serum contained HBV vaccine escape mutants (126S, 145R). Correlation between the methods was observed in results for escape mutants and common genotypes (A, B, C) in Japan. Observed during lamivudine therapy, an increase in HBsAg and HBV DNA concentrations preceded the aminotransferase (ALT) elevation associated with drug-resistant HBV variant emergence (breakthrough hepatitis). In conclusion, reliability of the Sysmex HBsAg quantitative assay was confirmed for all HBV genetic variants common in Japan. Monitoring of serum HBsAg concentrations in addition to HBV DNA quantification, is helpful in evaluation of the response to lamivudine treatment and diagnosis of the breakthrough hepatitis.

[False positive serum des-gamma-carboxy prothrombin after resection of hepatocellular carcinoma].

Measurements of serum concentrations of des-gamma-carboxy-prothrombin (PIVKA-II) are widely used for diagnosing hepatocellular carcinoma (HCC). Recently, when we evaluated the correlation of PIVKA-II between two commercially available PIVKA-II immunoassay kits (Lumipulse f vs. Picolumi) to introduce it in our hospital, false high values of PIVKA-II were observed in Lumipulse assay. Four(4%) of 100 serum samples showed false high values, and all of them were obtained from patients less than 2 month after curative resection of HCC. Examining additional 7 patients with HCC resection, serum samples from the 5 patients had the same trend. To elucidate the non-specific reaction by Lumipulse assay which utilized alkaline phosphatase (ALP) enzymatic reaction, inhibition assays by various absorbents such as inactive ALP and IgM antibodies were performed. Excess of inactive ALP reduced the high values of PIVKA-II. Note that anti-bleeding sheets (fibrinogen combined drug), which included bovine thrombin, were directly attached on liver of all patients with HCC resection in this study. As the sheets also contaminate ALP and probably produce IgM antibodies to ALP, the IgM may cross-react with anti-PIVKA-II antibodies directly. Taken together, it was suggested that produced antibodies against ALP derived from anti-bleeding sheets led false high values of PIVKA-II in the patients with HCC resection.

[Fundamental and clinical evaluation of hepatitis B virus core-related antigen assay by LUMIPULSE f].

A sensitive chemiluminescence enzyme immunoassay (CLEIA) has been developed for hepatitis B virus (HBV) core-related antigens (HBcrAg) detection. The HBcrAg is designated as the precore/core gene products including HBeAg. The aim of this study is to evaluate reproducibility of HBcrAg and correlation with HBV-DNA in serum using the automatic LUMIPULSE f to estimate an assay suitable for general laboratory use. In this study, we demonstrated that HBcrAg assay had highly intra-assay reproducible [coefficients of variation(CVs); 2.8-5.2%] and inter-assay reproducible [CVs; 3.9-9.1%]. When the cutoff value was tentatively set at 1 kU/ml, all healthy controls (HBsAg/HBV-DNA negative; n=100) and anti-HCV antibody-positive (n=50) sera were identified as negative. The assay showed a detection limit of 0.5 kU/ml using four serially diluted HBV high-titer sera, indicating higher sensitivity than HBV-DNA (transcription-mediated amplification). The HBcrAg concentration correlated positively with serum HBV-DNA (n=125, r = 0.860, p < 0.0001) regardless of HBeAg, although the HBcrAg levels were higher in HBeAg-positive group than in HBeAg-negative group. In the natural course of HBV infection, the HBcrAg concentration usually changed in accordance with HBV-DNA levels, however during lamivudine therapy the change of HBcrAg was more gradual than that of HBV-DNA. In conclusion, HBcrAg concentration provides a reflection of HBV virus load equivalent to HBV-DNA level, and the assay therefore offers a simple method for monitoring hepatitis B patients.

High stability of enzyme immunoassay for hepatitis C virus core antigen-evaluation before and after incubation at room temperature.

Hepatitis C virus (HCV) RNA is thought to be less stable than HCV core antigen (HCV-Ag), however there have been few studies on comparing the stability of HCV-Ag with that of HCV-RNA in vitro. The aim of this study is to evaluate serial levels of HCV-Ag and HCV-RNA in serum before and after incubation at 4 or 25 degrees C for 7 days to estimate an assay suitable for general laboratory use. In this study, we demonstrate that HCV-Ag levels are highly reproducible (coefficients of variation (CVs); 0.89-6.92%) and stable (84.8% of the initial level) with incubation of even 25 degrees C for 7 days, whereas HCV-RNA levels are much less reproducible (CVs; 9.13-29.66%) and decrease dramatically (15.1% of the initial level) after incubation, particularly at 25 degrees C. The measurement of the HCV-Ag level was found to be suitable for HCV quantification with serum samples stored either at 4 degrees C or under unknown conditions. Additionally, it successfully eliminated inhibitors such as heparin from plasma and could be applied to a variety of clinical specimens. Our data suggest the significance of measuring the HCV-Ag level during clinical management independently of the HCV-RNA level, particularly because of its high stability.