Letter to the editor: Suspected discrepancies due to inadequate quality of an in vitro analysis revealed by an in silico analysis.

The author's in vitro analysis results were compared with those of an in silico structure analysis of the relevant sequences obtained from the author's entire genome sequence data. It was speculated that the in silico results together with author's phylogenetic results demonstrate problems in the authors' published in vitro data, which were presumably due to an inadequate accuracy of an in vitro assay. It was fortuitously suggested that alignment images to an excess repeat structure of the same locus provide a improved speculation of a number of repeats and that accurate in vitro assays are expected to complementarily provide reliable insights in the era of whole genome sequencing.

Development of a transformer model for predicting the prognosis of patients with hepatocellular carcinoma after radiofrequency ablation.

INTRODUCTION: Radiofrequency ablation (RFA) is a widely accepted, minimally invasive treatment modality for patients with hepatocellular carcinoma (HCC). Accurate prognosis prediction is important to identify patients at high risk for cancer progression/recurrence after RFA. Recently, state-of-the-art transformer models showing improved performance over existing deep learning-based models have been developed in several fields. This study was aimed at developing and validating a transformer model to predict the overall survival in HCC patients with treated by RFA. METHODS: We enrolled a total of 1778 treatment-naïve HCC patients treated by RFA as the first-line treatment. We developed a transformer-based machine learning model to predict the overall survival in the HCC patients treated by RFA and compared its predictive performance with that of a deep learning-based model. Model performance was evaluated by determining the Harrel's c-index and validated externally by the split-sample method. RESULTS: The Harrel's c-index of the transformer-based model was 0.69, indicating its better discrimination performance than that of the deep learning model (Harrel's c-index, 0.60) in the external validation cohort. The transformer model showed a high discriminative ability for stratifying the external validation cohort into two or three different risk groups (p < 0.001 for both risk groupings). The model also enabled output of a personalized cumulative recurrence prediction curve for each patient. CONCLUSIONS: We developed a novel transformer model for personalized prediction of the overall survival in HCC patients after RFA treatment. The current model may offer a personalized survival prediction schema for patients with HCC undergoing RFA treatment.

Clinical utility of postablation liver tumor biopsy and possibility of gene mutation analysis.

AIM: Radiofrequency ablation (RFA) is regarded as a first-line treatment for hepatocellular carcinoma (HCC) at an early stage. When treated with RFA, tumor biopsy may not be performed due to the risk of neoplastic seeding. We previously revealed that the risk of neoplastic seeding is significantly reduced by performing biopsies after RFA. In this study, we investigated the possibility of pathological evaluation and gene mutation analysis of post-RFA tumor specimens. METHODS: Radiofrequency ablation was undertaken on diethylnitrosamine-induced mouse liver tumor, and tumor samples with or without RFA were subjected to whole exome sequencing. Post-RFA human liver tumor specimens were used for detection of TERT promoter mutations and pathological assessment. RESULTS: The average somatic mutation rate, sites of mutation, and small indels and base transition patterns were comparable between the nontreated and post-RFA tumors. We identified 684 sites of nonsynonymous somatic substitutions in the nontreated tumor and 704 sites of nonsynonymous somatic substitutions in the post-RFA tumor, with approximately 85% in common. In the human post-RFA samples, the TERT promoter mutations were successfully detected in 40% of the cases. Pathological evaluation was possible with post-RFA specimens, and in one case, the diagnosis of adenocarcinoma was made. CONCLUSION: Our findings suggest that post-RFA liver tumor biopsy is a useful and safe method for obtaining tumor samples that can be used for gene mutation analysis and for pathological assessment.

Steroid administration for ischemic complications after radiofrequency ablation: A retrospective study.

AIM: The aim of this study was to evaluate the effects of steroids on ischemic complications after radiofrequency ablation. METHODS: A total of 58 patients with ischemic complications were divided into two groups according to corticosteroid use or non-use. RESULTS: A total of 13 patients who were administered steroids had a shorter duration of fever than those who were not administered steroids (median 6.0 vs. 2.0 days; p < 0.001). Linear regression analysis showed that steroid administration was associated with a reduction of 3.9 days in the duration of fever (p = 0.008). CONCLUSIONS: Steroid administration for ischemic complications after radiofrequency ablation may reduce the risk of fatal outcomes by blocking systemic inflammatory reactions.

Improved prognosis of hepatitis C-related hepatocellular carcinoma in the era of direct-acting antivirals.

The prognostic impact of direct-acting antivirals (DAAs) on patients with hepatitis C-related hepatocellular carcinoma (C-HCC) is still unclear. This study aimed to evaluate the prognosis of C-HCC in the DAA era. We enrolled 1237 consecutive patients with treatment-naive C-HCC who underwent radical radiofrequency ablation between 1999 and 2019. We also enrolled 350 patients with nonviral HCC as controls. We divided these patients into three groups according to the year of initial treatment: 1999-2005 (cohort 1), 2006-2013 (cohort 2), and 2014-2019 (cohort 3). The use of antiviral agents and their effect in patients with C-HCC was investigated. Overall survival was evaluated for each cohort using the Kaplan-Meier method and a multivariable Cox proportional hazards regression model. Sustained virologic response (SVR) was achieved in 52 (10%), 157 (26%), and 102 (74%) patients with C-HCC in cohorts 1-3, respectively. The 3- and 5-year survival rates of patients with C-HCC were 82% and 59% in cohort 1; 80% and 64% in cohort 2; and 86% and 78% in cohort 3, respectively (p = 0.003). Multivariable analysis adjusted for age, liver function, and tumor extension showed that the prognosis of C-HCC improved in cohort 3 compared to cohort 1 (adjusted hazard ratio [aHR], 0.49; 95% confidence interval [CI], 0.32-0.73; p < 0.001), whereas the prognosis of nonviral HCC did not improve significantly (aHR, 0.96; 95% CI, 0.59-1.57; p = 0.88). The prognosis of C-HCC drastically improved with the advent of DAAs.

Clinical study of modulated electro-hyperthermia for advanced metastatic breast cancer.

Modulated electro-hyperthermia (mEHT) is a new treatment modality developed to overcome the problems associated with traditional hyperthermia; mEHT uses a precise impedance-matched system and modulated radiofrequency current flow to malignant tumors. It selects the malignant cells based on their biophysical differences, due to their high metabolic rate, individual (autonomic) behavior and membrane status. The aim of the present study was to report the outcomes of mEHT in the treatment of advanced breast cancer. mEHT was examined in 10 patients with advanced metastatic breast cancer and recurrent disease, who were considered incurable by standard therapy protocols. Of the 10 patients, partial response was achieved in 3, disease stability in 3, and progressive disease in 4; however, their quality of life was improved based on their subjective reports. No adverse effects were observed in any of the 10 patients. The present study demonstrated the feasibility of mEHT as a possible therapy for advanced breast cancer cases when standard therapies fail. Moreover, mEHT had no side effects and may be combined with various treatments for long-term therapy.

Mediastinoscopic salvage esophagectomy for recurrent esophageal squamous cell carcinoma after definitive chemoradiotherapy in a previously pneumonectomized patient.

We herein report a case of mediastinoscopic salvage esophagectomy for recurrent esophageal squamous cell carcinoma after definitive chemoradiotherapy in a previously pneumonectomized patient. A 66-year-old man with a medical history of left-sided pneumonectomy for lung cancer was diagnosed with local recurrence of lower esophageal squamous cell carcinoma (cT3N0M0 cStage II) 9 years after definitive chemoradiotherapy. The mediastinoscopic cervical approach and laparoscopic transhiatal approach were combined, and the thoracic esophagus was safely mobilized to separate the esophagus from the stump of the left bronchus and to divide dense adhesions between the esophagus and fibrotic tissue at the site of the previous left mediastinal pleural resection. The esophagectomy was uneventful and followed by reconstruction with a gastric conduit via the retrosternal route. The pathological diagnosis was esophageal squamous cell carcinoma (pT3-AD, pN1, M0, pStage III), indicating R0 resection. Even as salvage surgery, mediastinoscopic esophagectomy is a safe and curative treatment strategy for esophageal cancer patients who have previously undergone pneumonectomy.

Prognostic significance of KLF4 expression in gastric cancer.

To understand the roles of pluripotent stem cell-inducing genes in gastric cancer, the expression of Krüppel-like factor 4 (KLF4), Nanog, octamer-binding transcription factor 4 (Oct4), avian myelocytomatosis viral oncogene homolog (c-Myc) and sex-determining region Y-box 2 (SOX2) was examined using the newly developed gastric carcinoma tissue microarray. The associations between the immunohistochemical expression levels of the pluripotency-inducing factors and the clinicopathological data of 108 patients with gastric cancer were analyzed. No associations were identified between the expression levels of the five pluripotency-inducing factors and the tumor-node-metastasis (TNM) classification or clinicopathological characteristics of the patients. In addition, multivariate analysis revealed no association of Nanog, Oct4, SOX2 or c-Myc with the prognosis of the gastric cancer patients; however, low expression of KLF4 was determined to be an independent negative prognostic factor (P=0.0331), particularly in patients who underwent R0 resection (TNM stages 2 and 3; P=0.0048). In summary, low KLF4 expression was found to be negatively associated with overall survival, and may therefore be a useful prognostic marker in gastric cancer patients.

KLF4 and NANOG are prognostic biomarkers for triple-negative breast cancer.

BACKGROUND: Prognosis of breast cancer patients has been reported to depend on the expression of induced pluripotent stem (iPS) cell-inducing factors: KLF4 and NANOG. However, the relationship between KLF4 or NANOG expression in each breast cancer subtype and the life prognosis has not been elucidated. METHOD: KLF4 and NANOG expression levels were evaluated in 208 patients using a newly developed tissue microarray (TMA). In vitro, siRNA against klf4 (siKLF4) was transfected in TNBC cell line MDA-MB-231, and the expression of KLF4 was inhibited. RESULTS: Triple-negative breast cancer (TNBC) patients in KLF4 high-expression (upper) group had more favorable overall survival (OS) and disease-free survival (DFS) rates than KLF4 lower group (p = 0.0453 and p = 0.0427). In contrast, patients in the NANOG upper group had significantly poorer prognosis than lower group in TNBC breast cancer subtypes (p < 0.0001). Multivariate analysis showed that KLF4 (p = 0.0313), NANOG (p = 0.0002), and TNM stage (p = 0.0001) are mutually independent prognostic factors. It was also shown that the proliferation and invasion ability of siKLF4-induced TNBC cells were up-regulated significantly. CONCLUSION: Our findings suggested that KLF4 and NANOG expression levels were favorable prognostic factors for TNBC patients. KLF4 also had an ability to inhibit the proliferation and invasion of TNBC.

A new method for insertion of long intestinal tube for small bowel obstruction: Nonendoscopic over-the-wire method via short nasogastric tube.

It is often difficult to insert a long intestinal tube (LT) in patients with small bowel obstruction (SBO). We developed a novel technique for inserting an LT without endoscopy called nonendoscopic over-the-wire method via short nasogastric tube (NEWSt). We evaluated the efficacy and safety of NEWSt.We performed a retrospective study of patients who underwent LT insertion for SBO without any indications of strangulation with either NEWSt (n = 16) or endoscopy (n = 17) between November 2011 and February 2015 at our hospital. Univariate analysis was used to assess the success rate of LT placement beyond the duodenojejunal flexure, time required for the procedure, clinical outcomes, and adverse events.The success rate was 100% in both groups. Procedure time was numerically, but not statistically, shorter in the NEWSt group compared with the endoscopy group (24 ±â€Š13 vs 30 ±â€Š13 min; P = 0.174). There were no statistically significant differences between the 2 groups in terms of surgery rate (31% vs 12%; P = 0.225), fasting period (11.3 ±â€Š6.3 vs 9.9 ±â€Š4.5 days; P = 0.482), hospital stay (26.4 ±â€Š22.1 vs 18.7 ±â€Š7.0 days; P = 0.194), and recurrence rate (19% vs 24%; P = 1.0). No serious adverse event was observed in the NEWSt group, whereas serious aspiration pneumonia was observed in 2 patients after LT insertion in the endoscopy group.Without endoscopy, NEWSt enabled the high success rate and the short procedure time for the LT insertion. Prospective, randomized controlled trials are needed.

Molecular typing and genetic characterization of Mycobacterium avium subsp. hominissuis isolates from humans and swine in Japan.

Mycobacterium avium subsp. hominissuis (MAH) causes disease in both humans and swine; however, the genetic variations in MAH isolates are unclear. The aim of this study was to elucidate the genetic variations in MAH isolates from humans and swine in Japan. We analysed the 16S-23S rDNA internal transcribed spacer (ITS) sequence and variable number of tandem repeats (VNTRs) using the Mycobacterium avium tandem repeat loci, prevalence of ISMav6 and clarithromycin resistance for MAH isolates from patients with pulmonary MAC (pMAC) disease (n=69), and HIV-seropositive and blood culture-positive (HIV-MAC) patients (n=28) and swine (n=23). In the minimum spanning tree based on VNTR analysis, swine MAC isolates belonged to a cluster distinguishable from that of human pMAC isolates. Isolates from HIV-MAC were scattered throughout both clusters. The three major distinct sequevars, Mav-A, Mav-B and Mav-F, were determined according to 16S-23S rDNA ITS sequence analysis in addition to three new sequevars, Mav-Q, Mav-R and Mav-S. Mav-A and Mav-F comprised the majority of human pMAC strains; in contrast, Mav-B predominated in swine isolates. Distribution of ITS sequevars in the minimum spanning tree based on VNTR analysis showed similar clusters of isolates from different origins, i.e. human pMAC, HIV-MAC and swine. These results, together with ISMav6 possession and clarithromycin resistance, revealed the genetic diversity of MAH strains recovered from humans and swine. Molecular epidemiology and genetic characterization in the present study showed the distinctive genetic evolutionary lineage of MAH strains isolated from human pMAC diseases and swine.

ASSOCIATION BETWEEN A pMAH135 PLASMID AND THE PROGRESSION OF PULMONARY DISEASE CAUSED BY MYCOBACTERIUM AVIUM.

BACKGROUND: Pulmonary disease caused by nontuberculous mycobacteria has a variable clinical course. Although this is possibly the result of not only host factors, but also bacterial factors, many questions remain to be answered regarding these manifestations. METHODS: To assess the relationship between the progression of pulmonary Mycobacterium avium disease and bacterial factors we performed variable number tandem repeats (VNTR) typing analysis of M. avium tandem repeats (MATR) in M. avium isolates from 46 patients with different clinical courses, and furthermore, examined the association between disease progression and a pMAH135 plasmid derived from M. avium. RESULTS: In patients whose treatment was initiated because of worsenedchest radiograph findings and/or clinical symptoms within 18 months after being diagnosed with pulmonary M. avium disease, the detection rate of 6 genes located in pMAH135 was 35.3-47.1% for 17 isolates. However, in untreated patients with a stable condition, these rates were 10.3-13.8% in 29 isolates. MATR-VNTR typing analysis showed that isolates from patients with worsened disease and those with stable disease are clustered differently. In cluster III, the number of isolates from patients with worsened disease was higher than that from patients with stable disease (p = 0.019), and furthermore, the number of isolates carrying pMAH135 genes was higher than that not carrying pMAH135 genes (p ≤ 0.001). CONCLUSION: These results indicate an association between the progression of pulmonary M. avium disease and pMAH135. The presence of pMAH135 genes might be a useful prognostic indicator for pulmonary M. avium disease and may serve as one criterion for treatment initiation.

Perforation of intramural gastric metastasis during preoperative chemotherapy in a patient with thoracic esophageal squamous cell carcinoma.

INTRODUCTION: Perforation of intramural metastasis to the stomach (IMS) from esophageal cancer during chemotherapy has not been reported. PRESENTATION OF CASE: A 68-year-old male consulted our hospital due to appetite loss. He was diagnosed with advanced esophageal squamous cell carcinoma in the lower thoracic esophagus along with a large IMS in the upper stomach. The patient received preoperative chemotherapy of docetaxel, cisplatin, and 5-fluorouracil (DCF). During the second cycle of DCF, he had upper abdominal pain and was diagnosed with gastric perforation. Omental implantation repair for the perforation, peritoneal drainage, tube-gastrostomy, and tube-jejunostomy were performed. At 24 days after emergency surgery, he underwent thoracoscopic radical esophagectomy with total gastrectomy and reconstruction with colonic interposition. Pathological findings in the esophagus demonstrated complete replacement of the tumor by fibrosis. The gastric tumor was replaced by scar tissue with multinucleated giant cells along with a small amount of viable cancer cells. The patient was alive and healthy at 14 months after the radical operation, without tumor recurrence. DISCUSSION: The gastric perforation occurred due to rapid regression of the IMS which had involved the whole gastric wall before chemotherapy. Close monitoring to detect rapid tumor shrinkage during chemotherapy in patients with IMS may be warranted. A two-step operation was proposed to achieve safe curative treatment in patients with perforation of IMS during preoperative chemotherapy. CONCLUSION: We describe the first reported case of a patient with esophageal squamous cell carcinoma who showed perforation of IMS during preoperative chemotherapy.

A patient with paroxysmal nocturnal hemoglobinuria being treated with eculizumab who underwent laparoscopic cholecystectomy: report of a case.

Paroxysmal nocturnal hemoglobinuria (PNH) is acquired hemolytic anemia characterized by symptoms such as anemia and hemoglobinuria. In recent years, eculizumab as an anti-complement (C5) monoclonal antibody has been used for PNH and shown to have marked effects. We performed laparoscopic cholecystectomy in a patient with PNH being treated with eculizumab, and could avoid the risk of perioperative hemolysis and thrombosis. [Patient] The patient was a 48-year-old female who had developed PNH when she was 39 years old. At the age of 46 years, eculizumab administration was initiated once every 2 weeks. During the administration period, neither the progression of anemia nor hemoglobinuria was observed. In March 2013, gallstones were detected, and she was referred to our hospital for surgery. Eculizumab was administered 10 days before surgery, and laparoscopic cholecystectomy was performed in May 2013. After the operation, for the prevention of thrombosis, elastic stockings and a foot pump were used without anticoagulant administration. After the operation, neither the progression of anemia nor hemoglobinuria was observed. On postoperative day 5, eculizumab was administered as planned, and she showed a favorable general condition and was discharged. [Discussion] Perioperative care in PNH patients was conventionally considered to involve a high risk of developing anemia, thrombosis, or infection. However, after the advent of eculizumab, the control of the symptoms of PNH became possible in many patients. In this patient with PNH being treated with eculizumab, safe perioperative management was possible without the development of complications.

Characterization of a novel plasmid, pMAH135, from Mycobacterium avium subsp. hominissuis.

Mycobacterium avium complex (MAC) causes mainly two types of disease. The first is disseminated disease in immunocompromised hosts, such as individuals infected by human immunodeficiency virus (HIV). The second is pulmonary disease in individuals without systemic immunosuppression, and the incidence of this type is increasing worldwide. M. avium subsp. hominissuis, a component of MAC, causes infection in pigs as well as in humans. Many aspects of the different modes of M. avium infection and its host specificity remain unclear. Here, we report the characteristics and complete sequence of a novel plasmid, designated pMAH135, derived from M. avium strain TH135 in an HIV-negative patient with pulmonary MAC disease. The pMAH135 plasmid consists of 194,711 nucleotides with an average G + C content of 66.5% and encodes 164 coding sequences (CDSs). This plasmid was unique in terms of its homology to other mycobacterial plasmids. Interestingly, it contains CDSs with sequence homology to mycobactin biosynthesis proteins and type VII secretion system-related proteins, which are involved in the pathogenicity of mycobacteria. It also contains putative conserved domains of the multidrug efflux transporter. Screening of isolates from humans and pigs for genes located on pMAH135 revealed that the detection rate of these genes was higher in clinical isolates from pulmonary MAC disease patients than in those from HIV-positive patients, whereas the genes were almost entirely absent in isolates from pigs. Moreover, variable number tandem repeats typing analysis showed that isolates carrying pMAH135 genes are grouped in a specific cluster. Collectively, the pMAH135 plasmid contains genes associated with M. avium's pathogenicity and resistance to antimicrobial agents. The results of this study suggest that pMAH135 influence not only the pathological manifestations of MAC disease, but also the host specificity of MAC infection.

MicroRNA-203 inhibits the progression of esophageal squamous cell carcinoma with restored epithelial tissue architecture in vivo.

MicroRNA (miR)-203 has been shown to induce squamous differentiation of epidermal stem cells through the suppression of p63. The aim of this study was to assess the tumor suppressor effect of miR-203 in esophageal squamous cell carcinoma (ESCC) with focus on the regulation of the cell fate decisions and organization of tumor tissue architecture in vivo. Our investigation establishing stable clones from ESCC cell lines with induced miR-203 expression resulted in significant growth inhibition in a mouse xenograft model. Small foci were observed in xenograft tumors with stratified squamous differentiation in conjunction with restored baso-apical polarity. The expression of the basement membrane protein laminine was localized at the center of the foci and the basal cell marker p75NTR was expressed in the innermost layer. The expression of ki67 and p63 was co-localized at the center layers, while involucrin was expressed in the outer layers. Flow cytometry revealed that the p75NTR-positive cells expressing p63 and Bmi1 were well maintained, while the expression of p63 was suppressed in the p75NTR-negative cells. Our cDNA microarray analysis demonstrated the upregulation of genes involved in regulating tissue architecture, such as BMP-4 and ZO-1 in the mir-203 transfectant. Investigation using surgically removed ESCC specimens revealed that the expression of miR-203 significantly correlated with a favorable prognosis. These results demonstrated that miR-203 regulated both basal and supra-basal cell components to induce differentiation with restored epithelial tissue architecture, leading to significant tumor growth inhibition in vivo. Those results suggest the use of miR-203 as a novel therapeutic and diagnostic target in patients with ESCC.

[A case of locally advanced pancreatic cancer successfully resected after gemcitabine+S-1 therapy].

A 6 1-year-old man who was admitted to our hospital because of obstructive jaundice. He was diagnosed with locally advanced cancer of the pancreatic head on computed tomography. Gemcitabine (1,000 mg/m² on days 8 and 15, every 21 days) + S-1 (6 0 mg/m² on day 1-15, every 21 days) chemotherapy was administered because the tumor had invaded the common hepatic artery and portal vein. The tumor was reduced following 9 months of chemotherapy. Thus, subtotal stomach- preserving pancreaticoduodenectomy (SSPPD)was performed. The histopathological findings indicated no invasion of the cancer into the surrounding tissues. No recurrence has occurred 7 months after surgery. Neoadjuvant chemotherapy is important for effective treatment of locally advanced pancreatic cancer.

Comparative genome analysis of Mycobacterium avium revealed genetic diversity in strains that cause pulmonary and disseminated disease.

Mycobacterium avium complex (MAC) infection causes disseminated disease in immunocompromised hosts, such as human immunodeficiency virus (HIV)-positive patients, and pulmonary disease in persons without systemic immunosuppression, which has been increasing in many countries. In Japan, the incidence of pulmonary MAC disease caused by M. avium is about 7 times higher than that caused by M. intracellulare. To explore the bacterial factors that affect the pathological state of MAC disease caused by M. avium, we determined the complete genome sequence of the previously unreported M. avium subsp. hominissuis strain TH135 isolated from a HIV-negative patient with pulmonary MAC disease and compared it with the known genomic sequence of M. avium strain 104 derived from an acquired immunodeficiency syndrome patient with MAC disease. The genome of strain TH135 consists of a 4,951,217-bp circular chromosome with 4,636 coding sequences. Comparative analysis revealed that 4,012 genes are shared between the two strains, and strains TH135 and 104 have 624 and 1,108 unique genes, respectively. Many strain-specific regions including virulence-associated genes were found in genomes of both strains, and except for some regions, the G+C content in the specific regions was low compared with the mean G+C content of the corresponding chromosome. Screening of clinical isolates for genes located in the strain-specific regions revealed that the detection rates of strain TH135-specific genes were relatively high in specimens isolated from pulmonary MAC disease patients, while, those of strain 104-specific genes were relatively high in those from HIV-positive patients. Collectively, M. avium strains that cause pulmonary and disseminated disease possess genetically distinct features, and it suggests that the acquisition of specific genes during strain evolution has played an important role in the pathological manifestations of MAC disease.

[Extensive genetic analysis of clinical tuberculosis isolates and analysis of host factors to evaluate rapid development of multidrug resistance during initial treatment].

INTRODUCTION: In this study, we aimed at determining the cause of resistance to tuberculosis treatment by performing genetic analyses of bacteria obtained from a patient who developed multidrug-resistant tuberculosis (MDR-TB) during the initial course of treatment for tuberculosis. METHODS: Specimens obtained before and after the development of MDR-TB were subjected to spoligotyping, drug-resistance gene analysis, and variable-number tandem repeat (VNTR) typing. The patient's clinical background was also reviewed. RESULTS: After the development of resistance, the bacterial genome had changed with regard to only 1 mutation: S531L in the rpoB gene. Spoligotyping revealed that the genotype was that of the Beijing strain. VNTR typing confirmed all 35 loci. Review of the patient's clinical background showed that diabetes mellitus was present as a complication. DISCUSSION: There was no evidence of reinfection or polyclonal infection. The strain belonged to a sublineage of the Beijing genotype that is a common precipitating cause of MDR-TB due to this genotype. The patient had diabetes mellitus and was thus vulnerable to the development of resistance. Factors associated with both the host and bacteria, therefore, contributed to the development of resistance in this case, which seemed to result in the rapid development of MDR-TB.

Polymeric microfluidic devices exhibiting sufficient capture of cancer cell line for isolation of circulating tumor cells.

Here, we developed polymeric microfluidic devices for the isolation of circulating tumor cells. The devices, with more than 30,000 microposts in the channel, were produced successfully by a UV light-curing process lasting 3 min. The device surface was coated with anti-epithelial cell adhesion molecule antibody by just contacting the antibody solution, and a flow system including the device was established to send a cell suspension through it. We carried out flow tests for evaluation of the device's ability to capture tumor cells using an esophageal cancer cell line, KYSE220, dispersed in phosphate-buffered saline or mononuclear cell separation from whole blood. After the suspension flowed through the chip, many cells were seen to be captured on the microposts coated with the antibody, whereas there were few cells in the device without the antibody. Owing to the transparency of the device, we could observe the intact and the stained cells captured on the microposts by transmitted light microscopy and phase contrast microscopy, in addition to fluorescent microscopy, which required fluorescence labeling. Cell capture efficiencies (i.e., recovery rates of the flowing cancer cells by capture with the microfluidic device) were measured. The resulting values were 0.88 and 0.95 for cell suspension in phosphate-buffered saline, and 0.85 for the suspension in the mononuclear cell separation, suggesting the sufficiency of this device for the isolation of circulating tumor cells. Therefore, our device may be useful for research and treatments that rely on investigation of circulating tumor cells in the blood of cancer patients.