In Vitro Construction of Large-scale DNA Libraries from Fragments Containing Random Regions using Deoxyinosine-containing Oligonucleotides and Endonuclease V.

Efficient and precise construction of DNA libraries is a fundamental starting point for directed evolution of polypeptides. Recently, several in vitro selection methods have been reported that do not rely on cells for protein expression, where peptide libraries in the order of 1013 species are used for in vitro affinity selection. To maximize their potential, simple yet versatile construction of DNA libraries from several fragments containing random regions without bacterial transformation is essential. To address this issue, we herein propose a novel DNA construction methodology based on the use of polymerase chain reaction (PCR) primers containing a single deoxyinosine (I) residue near their 5' end. Treatment of the PCR products with endonuclease V generates 3' overhangs with customized lengths and sequences, which can be ligated accurately and efficiently with other fragments having exactly complementary overhangs. As a proof of concept, we constructed an artificial gene library of single-domain antibodies from four DNA fragments.

[The impact of direct-acting antiviral therapy on the diagnosis of hepatitis-C virus-associated hepatocellular carcinoma].

Since the introduction of direct-acting antiviral (DAA)-based combination therapies in September 2014 for patients with chronic hepatitis-C (CH-C), numerous patients have been diagnosed with hepatitis-C virus (HCV)-associated hepatocellular carcinomas (HCCs) during the screening performed prior to DAA therapy. The present study was conducted on the antiviral therapy for CH-C in two phases:i) the interferon (IFN) phase between January 2011 and August 2014 and ii) the DAA phase between September 2014 and September 2016. During the DAA phase, HCCs were detected in eight patients who were referred to our hospital for anti-HCV therapy. In contrast, HCCs were detected in only two patients during the IFN phase. The number of patients with newly detected HCC in the DAA phase (20.5%) who were referred for the anti-HCV therapy was significantly higher than that in the IFN phase (1.7%). Owing to the high efficacy and safety of the DAA therapy, the number of patients referred to our hospital for anti-HCV therapy increased from 40.5 persons/year in the IFN phase to 80.3 persons/year in the DAA phase. The average ages of patients in the DAA and IFN phases were 68 and 61 years, respectively. The increase in the number of patients with newly detected HCC referred for the anti-HCV therapy in the DAA phase could be attributed to the increase in the number of referred patients for anti-HCV therapy and the aging of these patients in the DAA phase. All the eight patients with newly detected HCC who were referred for anti-HCV therapy in the DAA phase received curative treatments. The median age, rate of liver cirrhosis, and median tumor size of the patients were 69 years, 13%, and 16mm. Therefore, the findings of this study indicate that DAA therapies not only eradicate HCV infection but also contribute to the early diagnosis of HCC by encouraging the HCV-infected patients to visit hospitals and by promoting active network between hepatologists and family physicians.

Serum pepsinogen levels can quantify the risk of development of metachronous gastric cancer after endoscopic resection.

We have previously reported that serum pepsinogen (PG) can quantify the level of gastric mucosal atrophy, and that H. pylori eradication reduces cancer development in subjects with mild atrophy identified by serum PG levels. The aim of this study was to elucidate the predictive ability of serum PG levels for the development of metachronous gastric cancer (MGC) after endoscopic resection (ER) of primary cancer in association with H. pylori eradication. A retrospective chart review was performed, and 330 patients who underwent ER for initial early gastric cancer were enrolled. Presence or absence of H. pylori, serum PG levels, and endoscopic atrophy at ER were evaluated. H. pylori eradication was performed at the patient's request after ER. The incidence of MGC in these patients was analyzed. Of 330 patients, 47 developed MGC. Endoscopic extensive atrophy was observed more frequently in patients with MGC (p = 0.001). Although PG I or PG II alone did not significantly differ according to development of MGC, the proportion of PG I/II ≤ 3.0, which is one of the criteria of PG test-positive, was significantly higher in patients with MGC (83 vs. 69%, p = 0.04). H. pylori eradication after ER did not affect MGC development (p = 0.2). On multivariate analysis, serum PG I/II ratio ≤ 3.3 was significantly associated with the development of MGC (hazard ratio: 3.66, 95% confidence interval: 1.47-12.25, p = 0.004). The risk of MGC after ER could be quantitatively predicted by the PG I/II ratio regardless of H. pylori status.

Severe enteropathy caused by α-heavy chain disease lacking detectable M-proteins.

A 57-year-old Japanese man was admitted to our hospital with diarrhea, weight loss and malabsorption. Due to a high serum IgA level, we suspected α-heavy chain disease (α-HCD). However, no monoclonal IgA was detected on protein electrophoresis or immunofixation. Immunohistochemical staining of intestinal biopsy specimens showed proliferation of CD138(+)IgA(+) cells, compatible with a diagnosis of α-HCD. Most α-HCD patients exhibit M-proteins in the serum on electrophoresis or immunoelectrophoresis; however, some patients lack detectable M-proteins, similar to our patient. Therefore, when α-HCD is suspected based on the clinical features, immunohistochemistry is required to make a diagnosis.