pH and Redox-Dual Sensitive Chitosan Nanoparticles Having Methyl Ester and Disulfide Linkages for Drug Targeting against Cholangiocarcinoma Cells.

The aim of this study is to prepare pH- and redox-sensitive nanoparticles for doxorubicin (DOX) delivery against DOX-resistant HuCC-T1 human cholangiocarcinoma (CCA) cells. For this purpose, L-histidine methyl ester (HIS) was attached to chitosan oligosaccharide (COS) via dithiodipropionic acid (abbreviated as ChitoHISss). DOX-incorporated nanoparticles of ChitoHISss conjugates were fabricated by a dialysis procedure. DOX-resistant HuCC-T1 cells were prepared by repetitive exposure of HuCC-T1 cells to DOX. ChitoHISss nanoparticles showed spherical morphology with a small diameter of less than 200 nm. The acid pH and glutathione (GSH) addition induced changes in the size distribution pattern of ChitoHISss nanoparticles from a narrow/monomodal distribution pattern to a wide/multimodal pattern and increased the fluorescence intensity of the nanoparticle solution. These results indicate that a physicochemical transition of nanoparticles can occur in an acidic pH or redox state. The more acidic the pH or the higher the GSH concentration the higher the drug release rate was, indicating that an acidic environment or higher redox states accelerated drug release from ChitoHISss nanoparticles. Whereas free DOX showed decreased anticancer activity at DOX-resistant HuCC-T1 cells, DOX-incorporated ChitoHISss nanoparticles showed dose-dependent anticancer activity. Intracellular delivery of DOX-incorporated ChitoHISss nanoparticles was relatively increased at an acidic pH and in the presence of GSH, indicating that DOX-incorporated ChitoHISss nanoparticles have superior acidic pH- and redox-sensitive behavior. In an in vivo tumor xenograft model, DOX-incorporated ChitoHISss nanoparticles were specifically delivered to tumor tissues and then efficiently inhibited tumor growth. We suggest that ChitoHISss nanoparticles are a promising candidate for treatment of CCA.

Reactive Oxygen Species-Sensitive Nanophotosensitizers of Methoxy Poly(ethylene glycol)-Chlorin e6/Phenyl Boronic Acid Pinacol Ester Conjugates Having Diselenide Linkages for Photodynamic Therapy of Cervical Cancer Cells.

The aim of this study is to fabricate nanophotosensitizers composed of methoxy poly(ethylene glycol) (mPEG), chlorin e6 (Ce6), and phenylboronic acid pinacol ester (PBAP) with diselenide linkages for reactive oxygen species (ROS)-sensitive photodynamic therapy (PDT) of cervical cancer cells. To fabricate nanophotosensitizers, Ce6 was conjugated with mPEG via selenocystamine linkage and then remaining carboxylic acid groups of Ce6 was attached to PBAP (mPEGseseCe6PBAP conjugates). Nanophotosensitizers of mPEGseseCe6PBAP conjugates were prepared by dialysis method. In transmission electron microscope (TEM) observation, nanophotosensitizers of mPEGseseCe6PBAP conjugates have spherical shapes and their diameters were less than 150 nm. The average diameter of mPEGseseCe6PBAP nanophotosensitizers was 92.7 ± 9.6 nm in particle size analysis. When H2O2 was added to the nanophotosensitizer solution, nanophotosensitizers were sensitively disintegrated according to the H2O2 concentration and then changed from monomodal distribution to multimodal distribution in particle size distribution. Furthermore, Ce6 release from nanophotosensitizers also increased according to the H2O2 concentration. When H2O2 was added to cell culture of HeLa human cervical cancer cells, intracellular Ce6 uptake of nanophotosensitizers were gradually increased according to the H2O2 concentration, indicating that nanophotosensitizers showed ROS-sensitive delivery of Ce6 against cancer cells.As well as free Ce6, nanophotosensitizers in the absence of light irradiation have low intrinsic cytotoxicity against RAW264.7 cells and HeLa cells. However, nanophotosensitizers induced cell death dose-dependently under light irradiation. Especially, nanophotosensitizers showed significantly higher ROS generation and phototoxicity against HeLa cells in vitro. When nanophotosensitizers were intravenously administered to animal tumor xenograft model of HeLa cells, tumor tissues revealed stronger fluorescence intensity than other tissues by light irradiation while absence of light irradiation induced relatively lower fluorescence intensity in tumor tissues, indicating that nanophotosensitizers have sensitivity against oxidative stress in tumor tissues. We suggest that nanophotosensitizers of mPEGseseCe6PBAP conjugates are promising vehicle for PDT of cervical cancer cells.

A Cancer-Favoring, Engineered Vaccinia Virus for Cholangiocarcinoma.

While oncolytic vaccinia virus-based therapy has shown promising results for uncured patients with cancer, its effects on cholangiocarcinoma (CCA) remain unclear. Here, we evaluated the anti-cancer activity of the cancer-favoring oncolytic vaccinia virus (CVV), which was recognized as a promising therapy for stem cell-like colon cancer cells (SCCs) and metastatic hepatocellular carcinoma (HCC) in previous studies. CCA presents major challenges, such as clinical complexity, stem cell cancer characteristics, a high refractory rate, resistance to conventional therapy, and a dismal prognosis. In the present study, we confirmed the oncolytic activity of the CVV in CCA with a slightly alkaline microenvironment (pH 7-8), in which the CVV was stable and highly effective at infecting CCA. Taken together, our findings suggest that CVV-based therapy is highly suitable for the treatment of CCA.

Second-look endoscopy and factors associated with delayed bleeding after endoscopic submucosal dissection.

Endoscopic submucosal dissection (ESD) is a widely used procedure as curative treatment for superficial gastric neoplasms, including early gastric cancer without lymph node metastasis. However, ESD requires advanced endoscopic skill and there is a major concern regarding complications from bleeding. So far, extensive efforts have been made to develop strategies to reduce post-ESD bleeding. Use of proton pump inhibitors and coagulating exposed vessels on the ulcer floor after ESD are strategies known to reduce the risk of delayed bleeding. Second-look endoscopy (SLE) is also carried out to reduce delayed bleeding following ESD in many institutions. However, the incidence of bleeding still remains around 5%, and further measures are needed to reduce delayed bleeding after gastric ESD. Recently, three randomized studies indicated that routine SLE was unnecessary. Although routine SLE may not be recommended for all patients after gastric ESD, SLE might be an important tool for the prevention of the delayed bleeding in selected high-risk patients. Thus, the identification of the risk factors, such as large size of resected specimen and treatment with multiple antiplatelet medications, may help to further guide clinicians in deciding whether to perform SLE. Studies carried out on larger cohorts are necessary to clarify the efficacy of SLE after ESD in the prevention of post-ESD bleeding in potentially high-risk patients.

A comparative study of DA-9601 and misoprostol for prevention of NSAID-associated gastroduodenal injury in patients undergoing chronic NSAID treatment.

Misoprostol is reported to prevent non-steroidal anti-inflammatory drug (NSAID)-associated gastroduodenal complications. There is, however, limited information regarding the efficacy of DA-9601 in this context. We performed a comparative study on the relative efficacy of DA-9601 and misoprostol for prevention of NSAID-associated complications. In this multicenter, double-blinded, active-controlled, stratified randomized, parallel group, non-inferiority trial, 520 patients who were to be treated with an NSAID (aceclofenac, 100 mg, twice daily) over a 4-week period were randomly assigned to groups for coincidental treatment with DA-9601 (60 mg, thrice daily) (236 patients for full analysis) or misoprostol (200 µg, thrice daily) (242 patients for full analysis). [corrected]. The primary endpoint was the gastric protection rate, and secondary endpoints were the duodenal protection rate and ulcer incidence rate. Endpoints were assessed by endoscopy after the 4-week treatment period. Drug-related adverse effects, including gastrointestinal (GI) symptoms, were also compared. At week 4, the gastric protection rates with DA-9601 and misoprostol were 81.4 % (192/236) and 89.3 % (216/242), respectively. The difference between the groups was -14.2 %, indicating non-inferiority of DA-9601 to misoprostol. Adverse event rates were not different between the two groups; however, the total scores for GI symptoms before and after administration were significantly lower in the DA-9601 group than in the misoprostol group (-0.2 ± 2.8 vs 1.2 ± 3.2; p < 0.0001). DA-9601 is as effective as misoprostol in preventing NSAID-associated gastroduodenal complications, and has a superior adverse GI effect profile.

Interpenetrating polymer network (IPN) scaffolds of sodium hyaluronate and sodium alginate for chondrocyte culture.

In this study, porous sodium hyaluronic acid/sodium alginate (HA/SA) scaffold based on interpenetrating polymeric network (IPN) technique has been fabricated, where HA and SA were cross-linked with poly(ethylene glycol) diglycidyl ether (PEGDG) and calcium chloride, respectively. The mean pore size and the swelling ratio of fabricated scaffolds decreased, and the compressive strength increased as the content of SA increased in HA/SA IPN scaffold. Rabbit chondrocytes were seeded within the HA/SA IPN scaffolds, and then their proliferation as well as chondrogenic differentiation was examined. DNA contents observed from the chondrocytes cultured in the IPN scaffolds increased with time over 21 days, which demonstrated that the rabbit chondrocytes continued to proliferate in HA/SA scaffolds. Results of the 1,9-dimethylmethylene blue (DMMB) and p-dimethylaminobenzaldehyde (DMBA) assays showed that glycosaminoglycan (s-GAG) and collagen contents increased over culture period, indicating the chondrogenic differentiation in the scaffold. Reverse transcription-polymerase chain reaction (RT-PCR) results showed the expression of type II collagen, the main chondrogenic differentiation marker. The bands indicating mRNA expression of type II collagen increased with the culture period. These results demonstrated that the porous HA/SA IPN scaffolds were successfully prepared and could serve as an effective delivery system of the three-dimensional culture of chondrocytes.

The role of hedgehog signaling during gastric regeneration.

BACKGROUND: Hedgehog signaling plays critical roles during embryonic development. It is also involved in tissue regeneration and carcinogenesis in various adult tissues. Moreover, it regulates the maintenance of cancer stem cells and adult stem cells. Although hedgehog signaling is important in gastric carcinogenesis, its role in gastric regeneration has not been previously examined. In the present study, we evaluated the expression and roles of hedgehog signaling during gastric regeneration. METHODS: Gastric ulcers were induced by serosal application of an acetic acid solution in mice. Sham-operated mice served as controls. The proliferation of gastric progenitor cells was studied using bromodeoxyuridine (BrdU). The expression of hedgehog signaling molecules and the differentiation of gastric progenitor cells were examined by immunohistochemical staining and Western blotting. RESULTS: One day after the induction of gastric ulcer, the proliferation of gastric progenitor cells increased; however, the expression of hedgehog signaling molecules, including sonic hedgehog (Shh), Indian hedgehog (Ihh), desert hedgehog (Dhh), and patched (Ptch1) decreased at the ulcer margin. From 5 days after the induction of gastric ulcer, newly generated gastric glands and their differentiation were observed at the ulcer margin. The expression of hedgehog signaling molecules gradually increased in the newly generated gastric glands of the ulcer margin. Cyclopamine, a specific inhibitor of hedgehog signaling, significantly inhibited the differentiation of mucous cells and parietal cells during the gastric regeneration process. CONCLUSION: The above results suggest that hedgehog signaling is involved in the differentiation of gastric progenitor cells during the gastric ulcer repair process.

Detection of celiac ganglia with radial scanning endoscopic ultrasonography.

BACKGROUND/AIMS: It has been recently reported that celiac ganglia can be identified by linear-array endoscopic ultrasonography (EUS). Still, there has been no report on the detection rate of celiac ganglia with radial scanning EUS. The aim of this study was to evaluate the detection rate of celiac ganglia by radial scanning echoendoscopy during a routine examination. METHODS: We prospectively enrolled 57 consecutive patients (23 men, 34 women; mean age 54 years, range 21-78 years) who were referred for EUS examination from September 2006 to December 2006. EUS was performed using a radial scanning echoendoscope. The size, location and EUS appearance of the celiac ganglia were recorded for each patient. RESULTS: Celiac ganglia were identified in 51 out of 57 patients (89.4%). They were identified at the left side of the celiac trunk and aorta and between the celiac artery and the left adrenal gland. They appeared as hypoechoic, oblong or lobulated structures, often with an irregular edge, and they often contained a hyperechoic focus or strand. The mean size was 18 mm by 4 mm. Structures corresponding to the visualized celiac ganglia were retrospectively identified on CT scans in 33 among the 37 patients (89.2%). CONCLUSIONS: The results of this study showed that celiac ganglia could be identified, with radial scanning EUS, in the majority of subjects.

Toward understanding the mechanism of nonlinear optical characteristics of PbTe thin film for nano-optical memory.

An experimental study is conducted toward understanding the mechanism of nonlinear optical properties of PbTe thin film that were demonstrated potentially usable for nano-optical memory based on super-resolution technology. By way of a real time optical-electrical characterization of a PbTe thin film device, it is found that absorption coefficient decreases with increasing laser power, accompanied by increase in carrier concentration. From z-scan measurements, nonlinear optical coefficient due to a long pulse (1 micros) z-scan is found nearly 3 order of magnitude higher than the one due to a short pulse (30 ps) z-scan when input energy density is relatively comparable. Conceivably, these experimental findings call for a physical model that is able to account for the prevailing role of a thermal contribution within the framework of absorption saturation by band filling. We speculate that the absorption saturation might be enhanced dramatically by making various indirect interband transitions possible via participation of phonons in a photonic excitation process.

Endoscopic grading of atrophic gastritis is inversely associated with gastroesophageal reflux and gastropharyngeal reflux.

BACKGROUND: Reflux esophagitis is inversely associated with the presence of atrophic gastritis, and endoscopic grading of atrophic gastritis correlates with histological evaluation. The aim of this study was to investigate the association of the endoscopic grade of atrophic gastritis with gastroesophageal and gastropharyngeal reflux. METHODS: A total of 627 patients, who underwent endoscopy and ambulatory 24-hour dual-probe pH monitoring, were included in this study. The grade of atrophic gastritis was endoscopically classified into 2 types with the atrophic pattern system: the closed-type (C-type) and the open-type (O-type). We compared the findings from endoscopy and ambulatory pH monitoring for these 2 types. RESULTS: The O-type was significantly associated with a lower prevalence of reflux esophagitis (p = 0.001). All variables showing gastroesophageal reflux in the distal probe were significantly lower in the O-type than in the C-type (p < 0.05). Similarly for the proximal probe, all variables, except the supine time of pH < 4, were significantly lower in the O-type than in the C-type (p < 0.05). The frequency of gastroesophageal reflux disease and gastropharyngeal reflux disease was in significantly lower in the O-type than in the C-type (p < 0.001, p = 0.012, respectively). CONCLUSIONS: Endoscopic grading of atrophic gastritis is easy and is inversely associated with gastroesophageal and gastropharyngeal reflux.

Adult intussusception caused by cystic lymphangioma of the colon: a rare case report.

We experienced a case of intussusception caused by cys- tic lymphangioma of the colon in a 32 years old female who was admitted to our hospital for the chief complaint of bloody stool. In the colonoscopic examination, cystic mass with stalk which had smooth mucosal surface was noted at the descending colon. Abdominal ultrasonography and computed tomography revealed left colon intussusception with a multilocular cystic tumor as a leading point. Emergent operation was performed. On the histopathologic examination, the cystically dilated spaces lined by endothelium and septated by fibrous septa were present. The pathological diagnosis was cystic lymphangioma of the colon. Although intussusception due to lymphangioma in an adult are rare, it should be taken into consideration that it is possible diagnosis.