Resection depth and layer of underwater versus conventional endoscopic mucosal resection of intermediate-sized colorectal polyps: A pilot study.

Background and study aims Curability of colorectal tumors is associated with resection depth and layer in endoscopic resection. Underwater endoscopic mucosal resection (UEMR) has not undergone sufficient histopathological evaluation. We conducted a pilot study to compare the effectiveness, including resection depth and layer, of UEMR and conventional endoscopic mucosal resection (CEMR). Patients and methods This study was a single-center, retrospective study. Patients with colorectal lesions were treated by UEMR or CEMR between January 2018 and March 2020. Eligible patients were selected from included patients in a 1:1 ratio using propensity score matching. We compared the resection depth and layer and treatment results between the UEMR and CEMR groups. Results We evaluated 55 patients undergoing UEMR and 291 patients undergoing CEMR. Using propensity score matching, we analyzed 54 lesions in each group. The proportion of specimens containing submucosal tissue was 100 % in both groups. The median thickness of the submucosal tissue was significantly greater in the CEMR group than in the UEMR group [1235 µm (95 % confidence interval [CI], 1020-1530 µm) vs. 950 µm (95 % CI, 830-1090 µm), respectively]. However, vertical margins were negative in all lesions in both groups. Conclusions Our findings suggest that the median thickness of submucosal tissue in the UEMR group was about 1,000 µm. Even though the resection depth achieved with UEMR was more superficial than that achieved with CEMR, UEMR may be a treatment option, especially for colorectal lesions ≤ 20 mm in diameter without suspicious findings of submucosal deeply invasive cancer.

Organ accumulation and carcinogenicity of highly dispersed multi-walled carbon nanotubes administered intravenously in transgenic rasH2 mice.

PURPOSE: Multiwalled carbon nanotubes (MWCNTs) have been known to enter the circulatory system via the lungs from inhalation exposure; however, its carcinogenicity and subsequent accumulation in other organs have not been adequately reported in the literature. Moreover, the safety of MWCNTs as a biomaterial has remained a matter of debate, particularly when the material enters the circulatory system. To address these problems, we used carcinogenic rasH2 transgenic mice to intravenously administer highly dispersed MWCNTs and to evaluate their carcinogenicity and accumulation in the organs. METHODS: Two types of MWCNTs (thin- and thick-MWCNTs) were intravenously administered at a high dose (approximately 0.7 mg per kg body weight) and low dose (approximately 0.07 mg per kg body weight). RESULTS: MWCNTs showed pancreatic accumulation in 3.2% of mice administered with MWCNTs, but there was no accumulation in other organs. In addition, there was no significant difference in the incidence of tumor among the four MWCNTs-administered groups compared to the vehicle group without MWCNTs administration. Blood tests revealed elevated levels in mean red blood cell volume and mean red blood cell hemoglobin level for the MWCNTs-administered group, in addition to an increase in eotaxin. CONCLUSION: The present study demonstrated that the use of current technology to sufficiently disperse MWCNTs resulted in minimal organ accumulation with no evidence of carcinogenicity.

A three-dimensional block structure consisting exclusively of carbon nanotubes serving as bone regeneration scaffold and as bone defect filler.

Many recent studies have been conducted to assess the ability of composite materials containing carbon nanotubes (CNTs) with high bone affinity to serve as scaffolds in bone regenerative medicine. These studies have demonstrated that CNTs can effectively induce bone formation. However, no studies have investigated the usefulness of scaffolds consisting exclusively of CNTs in bone regenerative medicine. We built a three-dimensional block entity with maximized mechanical strength from multi-walled CNTs (MWCNT blocks) and evaluated their efficacy as scaffold material for bone repair. When MWCNT blocks containing recombinant human bone morphogenetic protein-2 (rhBMP-2) were implanted in mouse muscle, ectopic bone was formed in direct contact with the blocks. Their bone marrow densities were comparable to those of PET-reinforced collagen sheets with rhBMP-2. On day 1 and day 3, MC3T3-E1 preosteoblasts were attached to the scaffold surface of MWCNT blocks than that of PET-reinforced collagen sheets. They also showed a maximum compression strength comparable to that of cortical bone. Our MWCNT blocks are expected to serve as bone defect filler and scaffold material for bone regeneration.

Wtip is required for proepicardial organ specification and cardiac left/right asymmetry in zebrafish.

Wilm's tumor 1 interacting protein (Wtip) was identified as an interacting partner of Wilm's tumor protein (WT1) in a yeast two-hybrid screen. WT1 is expressed in the proepicardial organ (PE) of the heart, and mouse and zebrafish wt1 knockout models appear to lack the PE. Wtip's role in the heart remains unexplored. In the present study, we demonstrate that wtip expression is identical in wt1a­, tcf21­, and tbx18­positive PE cells, and that Wtip protein localizes to the basal body of PE cells. We present the first genetic evidence that Wtip signaling in conjunction with WT1 is essential for PE specification in the zebrafish heart. By overexpressing wtip mRNA, we observed ectopic expression of PE markers in the cardiac and pharyngeal arch regions. Furthermore, wtip knockdown embryos showed perturbed cardiac looping and lacked the atrioventricular (AV) boundary. However, the chamber­specific markers amhc and vmhc were unaffected. Interestingly, knockdown of wtip disrupts early left­right (LR) asymmetry. Our studies uncover new roles for Wtip regulating PE cell specification and early LR asymmetry, and suggest that the PE may exert non­autonomous effects on heart looping and AV morphogenesis. The presence of cilia in the PE, and localization of Wtip in the basal body of ciliated cells, raises the possibility of cilia-mediated PE signaling in the embryonic heart.

Specific biological responses of the synovial membrane to carbon nanotubes.

Biological evaluation of carbon nanotubes (CNTs) is typically performed in the lung or abdominal cavity; however, biological reactions to CNTs are predicted to be markedly different in other tissues. In applications of CNTs as reinforcement for artificial joints and drug delivery systems, including their use in bone regeneration, the intra-articular synovial membrane makes contact with the CNTs. Herein, we analyzed the reaction of the synovial membrane with multiwalled CNTs (MWCNTs). Injection of MWCNTs into rat knee joints revealed their dose-dependent incorporation into deep synovial membranes and the formation of granulation tissue, without long-term inflammation. MWCNTs were incorporated into human fibroblast-like synoviocytes (HFLSs), with less cytotoxicity than that observed in macrophages (RAW264 cells). Moreover, MWCNTs inhibited the release of cytokines and chemokines from HFLSs. The reaction of the synovial membrane with MWCNTs differed from that observed in other tissues; thus, detailed biological evaluation at each target site is necessary for clinical applications.

Biological responses according to the shape and size of carbon nanotubes in BEAS-2B and MESO-1 cells.

This study aimed to investigate the influence of the shape and size of multi-walled carbon nanotubes (MWCNTs) and cup-stacked carbon nanotubes (CSCNTs) on biological responses in vitro. Three types of MWCNTs - VGCF(®)-X, VGCF(®)-S, and VGCF(®) (vapor grown carbon fibers; with diameters of 15, 80, and 150 nm, respectively) - and three CSCNTs of different lengths (CS-L, 20-80 µm; CS-S, 0.5-20 µm; and CS-M, of intermediate length) were tested. Human bronchial epithelial (BEAS-2B) and malignant pleural mesothelioma cells were exposed to the CNTs (1-50 µg/mL), and cell viability, permeability, uptake, total reactive oxygen species/superoxide production, and intracellular acidity were measured. CSCNTs were less toxic than MWCNTs in both cell types over a 24-hour exposure period. The cytotoxicity of endocytosed MWCNTs varied according to cell type/size, while that of CSCNTs depended on tube length irrespective of cell type. CNT diameter and length influenced cell aggregation and injury extent. Intracellular acidity increased independently of lysosomal activity along with the number of vacuoles in BEAS-2B cells exposed for 24 hours to either CNT (concentration, 10 µg/mL). However, total reactive oxygen species/superoxide generation did not contribute to cytotoxicity. The results demonstrate that CSCNTs could be suitable for biological applications and that CNT shape and size can have differential effects depending on cell type, which can be exploited in the development of highly specialized, biocompatible CNTs.

Culture medium type affects endocytosis of multi-walled carbon nanotubes in BEAS-2B cells and subsequent biological response.

We examined the cytotoxicity of multi-walled carbon nanotubes (MWCNTs) and the resulting cytokine secretion in BEAS-2B cells or normal human bronchial epithelial cells (HBEpCs) in two types of culture media (Ham's F12 containing 10% FBS [Ham's F12] and serum-free growth medium [SFGM]). Cellular uptake of MWCNT was observed by fluorescent microscopy and analyzed using flow cytometry. Moreover, we evaluated whether MWCNT uptake was suppressed by 2 types of endocytosis inhibitors. We found that BEAS-2B cells cultured in Ham's F12 and HBEpCs cultured in SFGM showed similar biological responses, but BEAS-2B cells cultured in SFGM did not internalize MWCNTs, and the 50% inhibitory concentration value, i.e., the cytotoxicity, was increased by more than 10-fold. MWCNT uptake was suppressed by a clathrin-mediated endocytosis inhibitor and a caveolae-mediated endocytosis inhibitor in BEAS-2B cells cultured in Ham's F12 and HBEpCs cultured in SFGM. In conclusion, we suggest that BEAS-2B cells cultured in a medium containing serum should be used for the safety evaluation of nanomaterials as a model of normal human bronchial epithelial cells. However, the culture medium composition may affect the proteins that are expressed on the cytoplasmic membrane, which may influence the biological response to MWCNTs.

[A case of multiple metastases breast cancer controlled using S-1 as third-line chemotherapy].

A 42-year-old female underwent surgery for cancer of the left breast (T3N2M0) in February 2003, and FEC 70, followed by CMF, was administered as adjuvant therapy. In January 2009, second-line chemotherapy with weekly paclitaxel therapy was started after multiple pleural and bone metastatic lesions had been found. Despite this treatment, she required radiation therapy for the growth of bone metastatic lesions. As paclitaxel apparently had no useful effect on the lesions, S-1 chemotherapy, given as third-line therapy starting in December 2009, was considered useful for disease control without progression demonstrated by PET evaluation.

Anastomotic suture line recurrence of early rectal carcinomas that had been resected by laparoscopic surgery.

We report herein a case of a 64-year-old woman found to have anastomotic suture line recurrence of an early rectal carcinoma. The patient had undergone laparoscopy-assisted low anterior rectal resection for an early rectal carcinoma 2 years before the anastomotic site recurrence. A follow-up colonoscopy revealed an elevated lesion on the anastomotic suture line. The diagnosis of adenocarcinoma was confirmed by biopsy. The patient underwent a resection of the remnant rectum. Histological examination of the resected specimen showed that the anastomotic site recurrence might have been caused by intraluminal implantation from the primary rectal cancer. We speculate that intraluminal implantation might be caused by insufficient intraoperative rectal irrigation because of limited access often encountered in laparoscopic surgery. We propose that it is necessary to devise a method with which to perform sufficient intraoperative rectal irrigation in laparoscopic surgery for rectal carcinoma.

Giant peritoneal loose body in the pelvic cavity: report of a case.

This report describes a giant peritoneal loose body in the pelvic cavity. A 63-year-old man who was asymptomatic underwent a routine medical examination, which revealed a tumor in the pelvic space. Computed tomography and magnetic resonance imaging showed a smooth-surfaced mass with two marked calcifications in the central position. Preoperatively, we suspected a calcified leiomyoma originating from the wall of the sigmoid colon; however, at laparoscopic surgery we extracted a hard, egg-shaped mass 5 cm in diameter, with detached appendices epiploicae. Histological examination revealed that this peritoneal loose body was made up of thick layers of fibrous tissue with a few cellular components, and necrotic fat tissue in the central position. Small peritoneal loose bodies are occasionally found during laparotomy or autopsy, but such a large one is very unusual.

Gene expression screening using a cDNA macroarray to clarify the mechanisms of peritoneal dissemination of pancreatic cancer.

PURPOSE: Pancreatic cancer is associated with the poorest prognosis of any digestive cancer due to the high incidence of peritoneal dissemination, which is the cause of death in most cases. To determine the mechanisms of peritoneal dissemination in pancreatic cancer, we established a mouse model of high peritoneal dissemination. METHODS: A novel highly peritoneal-disseminating cell line was established from the human pancreatic cancer cell line; CAPAN-1. The new cell line, CAPAN-1P4a, was established from CAPAN-1 by repeated in vivo selection (four times) of the tumor cell line. To clarify the candidate genes implicated in peritoneal dissemination of pancreatic cancer, global gene expression screening was done using a cDNA macroarray. RESULTS: CAPAN-1P4a cells showed 100% metastasis 3 weeks after injection and high reproducibility in the inoculated mice. Twenty-seven genes were upregulated and 14 genes were downregulated in CAPAN-1P4a cells compared with CAPAN-1 cells. The genes differentially expressed in the two cell lines were included as tumor suppressor/apoptosis genes, regulatory transcription factor, membrane receptors, cell adhesion protein, membrane receptors, and so on. CONCLUSIONS: Our established CAPAN-1P4a model offers a new means of conducting global gene expression analysis of pancreatic cancer cells with peritoneal dissemination and it has the potential to provide new insights into the mechanism of peritoneal dissemination in human pancreatic cancer.

A new liver metastatic and peritoneal dissemination model established from the same human pancreatic cancer cell line: analysis using cDNA macroarray.

To elucidate the mechanisms of metastasis, we established two sublines HPC-1H5 with a highly liver metastatic cell line and HPC-1P5a with a highly peritoneal disseminating cell line, which were sequentially selected from the parental pancreatic cancer cell line HPC-1. Using these three cell lines, we investigated several biological properties and mRNA levels of differentially-expressed genes involved in cancer metastasis by cDNA macroarray. Microscopic findings for the three cell lines were the same. The tumorigenicity, in vitro growth ability, motile activity, adhesive activity and the production of IL-8 of metastatic sublines were higher than those of parental HPC-1 cells. Particularly, HPC-1H5 cells showed clearly higher levels of IL-8 expression and tumors of HPC-1H5 cells grew faster and bigger than those of HPC-1P5a cells. In cDNA macroarray analysis of HPC-1H5 cells, 22 genes were up-regulated and 44 genes were down-regulated compared with parental HPC-1 cells. In HPC-1P5a cells, 9 genes were up-regulated and 28 genes were down-regulated compared with parental HPC-1 cells. This study provides a demonstration of global gene expression analysis of pancreatic cancer cells with liver metastasis and peritoneal dissemination. Furthermore, our results provide a new insight into the study of liver metastasis and peritoneal dissemination of human pancreatic cancer.

Malignant melanoma of the anorectum: report of four cases.

Four cases of anorectal malignant melanoma are reported in this paper. All patients underwent an abdominoperineal resection with lymph node dissection for a curative operation and received postoperative chemotherapy with dacarbazine, ranimustine, and vincristine, either with or without interferon-beta. One of these patients has been observed for more than 6 years postoperatively without any evidence of recurrence. The other three patients had advanced diseases at the time of diagnosis, and died within 3 years after operation. The prognosis of anorectal malignant melanoma is considered to be directly related to tumor size and depth. Therefore, a staging system and treatments based on the tumor size and depth (or thickness) are needed.

Transanal repair of rectourethral fistula after a radical retropubic prostatectomy: report of a case.

Rectourethral fistula occurred in a 64-year-old man after a radical prostatectomy. Despite conservative treatment the fistula did not close spontaneously. Eleven months after the original prostatectomy, an operation was performed. We chose the Latzko technique with slight modifications as follows. The patient was placed in the prone jackknife position. The fistula was found at a site about 6.0 cm from the anal verge. An elliptical area of rectal mucosa was incised about 1.5 cm from the fistulous orifice and subsequently the rectal mucosa was denuded. The submucosa was dissected above the fistula about 2.0 cm from the edge of the incision. The fistula was then closed with one layer of side-by-side absorbable 2-0 polyglactin sutures. The dissected rectal mucosal flap was brought down over the fistula and sutured in one layer to the distal edge of the rectal muscularis propria through the mucosa with 3-0 polyglactin sutures. On postoperative day 21 a retrograde urethrogram was made and it showed no leakage of urine via the rectum. This procedure is a simple, effective, and minimally morbid technique for the repair of rectourethral fistula after a radical prostatectomy, although it is only useful for the treatment of low rectourethral fistulas.

A novel nude mouse model of liver metastasis and peritoneal dissemination from the same human pancreatic cancer line.

INTRODUCTION: Recently, several mice models have been used for investigating cancer metastasis. However, there are no metastatic and peritoneal dominated variants from the same parental cell line. AIM AND METHODOLOGY: To elucidate the mechanisms of metastasis, we established highly liver metastatic and peritoneal disseminated models in nude mice, and then characterized several factors related to metastasis in these cells. We established a series of well-characterized sublines that showed metastatic potentials to different organ sites of nude mice. Two sublines were selected sequentially from the parental pancreatic cancer cell line, HPC-4, resulting in a highly liver metastatic cell line, HPC-4H4, and a highly peritoneal disseminated cell line, HPC-4P4a. Using these three cell lines, we investigated several biologic properties and mRNA levels of differentially expressed genes involved in cancer metastasis. RESULTS: The tumorigenicity, the motile activity, and the adhesive activity of metastatic sublines were higher than those of parental HPC-4 cells. Macroscopic and microscopic findings and the DNA ploidy pattern were the same among the three cell lines. In addition, HPC-4H4 cells expressed clearly higher levels of vascular endothelial growth factor and IL-8 expression than did HPC-4P4a cells. In fluorescence-activated cell sorter analysis of adhesion molecules, the expression of integrin-alpha2 was enhanced in HPC-4 cells, integrin-alphavbeta5 was enhanced in HPC-4H4 cells, and integrin-alpha3 was enhanced in HPC-4P4a cells. Osteopontin, vascular endothelial growth factor, and hepatocyte growth factor were among the genes that were upregulated in HPC-4H4 cells compared with HPC-4P4a cells. HPC-4P4a cells did not metastasize to the liver by intrasplenic injection. Conversely, HPC-4H4 cells metastasized remarkably to the peritoneum by intraabdominal injection. CONCLUSION: These sublines are the first reported liver metastatic and peritoneal disseminated models derived from the same parental cell lines. The results of our study suggest that the process of hematogenous metastasis is not the same as that of peritoneal dissemination.