Risk factors associated with multiple and missed gastric neoplastic lesions after endoscopic resection: prospective study at a single institution in south Korea.

BACKGROUND/AIMS: Only a small part of visible gas tric mucosal lesion can be removed by endoscopic resection. This study is aimed to identify incidence rate and associated risk factors of multiple and missed gastric lesions, and proper timing of follow-up en doscopy. METHODOLOGY: Endoscopic surveillance was performed on 1 week, and 1, 6, 12 months af ter endoscopic resection. All multiple gastric lesions were divided into main and accessory lesions. The accessory lesions were subdivided into detected and missed lesions. RESULTS: Totally, 250 lesions of 215 patients were analyzed. There were 81 early gastric cancers, 50 high grade dysplasias and 119 low grade dysplasias. Thirty patients (14%) had multiple gastric neoplastic lesions, either adenoma or cancer, within 1 year follow-up after endoscopic resection. Old age, male gender and severe intestinal metaplasia were independent risk factors of multiple gastric lesions. Small size (≤ 1 cm) and flat morphology were major risk factors of missed lesion. Among 10 missed lesions, 9 (90%) could be detected within 6 month after resection. CONCLUSIONS: Old age, male gender, severe intestinal metaplasia were risk factors for multiple gastric lesions after endoscopic resection. Follow-up endoscopy is needed at least one time within six months after resection, with careful inspection of entire stomach.

Is the rate of postoperative complications following laparoscopy-assisted gastrectomy higher in elderly patients than in younger patients?

BACKGROUND: With an increase in life expectancy, very elderly patients are presenting with gastric cancer more commonly than ever. The present study retrospectively analyzed the surgical outcomes of laparoscopy-assisted gastrectomy for gastric cancer in the young, elderly, and very elderly age groups. METHODS: The study group consisted of 1,055 patients who underwent laparoscopy-assisted gastrectomy between February 2002 and December 2012. We divided these patients into three groups; group 1 (young age, <65 years), group 2 (elderly age, 65-74 years), and group 3 (very elderly age, ≥75 years). RESULTS: There were statistical differences in the rates of postoperative complications among the three groups (P = 0.008). However, when assessed according to the severity of postoperative complications based on the Clavien-Dindo classification, there was no statistical difference among the three groups (P = 0.562). CONCLUSIONS: Laparoscopy-assisted gastrectomy for gastric cancer can be performed in very elderly patients. In analyzing studies of elderly patients with postoperative complications following the procedure, not only should the rate of postoperative complications be taken into consideration, but also the severity of any postoperative complications.

Risk factors for duodenal stump leakage after gastrectomy for gastric cancer and management technique of stump leakage.

BACKGROUND/AIMS: The goal of this study was to elucidate the risk factors for duodenal stump leakage after gastrectomy for gastric cancer. In addition, the management of duodenal stump leakage is reviewed. METHODOLOGY: From January 2002 through December 2012, 1,195 patients with gastric cancer who underwent gastric R0 resection were enrolled in this study. The clinicopathologic features, postoperative outcomes (i.e., operation time, hospital stay, surgical procedures, method of duodenal stump closure, retrieved lymph nodes), and the risk factors of duodenal stump leakage were analyzed. RESULTS: Of the 1,195 patients, 13 patients (1.1%) suffered duodenal stump leakage. Most of the patients with duodenal stump leakage were male (92.3%). Nine patients underwent a subtotal gastrectomy with Billroth- II or Roux-en-Y anastomosis; the other four patients underwent a total gastrectomy with a Roux-en-Y anastomosis. There were two mortalities. With univariate and multivariate analysis, age was the most predictable factor for duodenal stump leakage (p= 0.034, p=0.044) CONCLUSIONS: Duodenal stump leakage was affected by the age. For older patients who undergo a radical gastrectomy for gastric cancer, the surgeon must pay meticulous attention to the transection and mobilization of the duodenum in order to prevent duodenal stump leakage.

The differences in clinicopathological features and prognosis among the subtypes of signet ring cell, mucinous, papillary, and lymphoepithelioma-like carcinoma in advanced gastric cancer.

BACKGROUND/AIMS: There are differing histologic subtypes of gastric cancer. We investigated the clinicopathological features and prognosis of: signet ring cell (SRC), mucinous (MGC), papillary (PGC), and lymphoepithelioma-like (LELC) carcinoma in advanced gastric cancer. METHODOLOGY: One hundred thirty six advanced gastric cancer patients, including 62 SRCs, 43 MGCs, 9 PGCs, and 22 LELCs, who underwent R0 gastrectomy between 2002 and 2013, were retrospectively evaluated. RESULTS: There were significant differences in several clinicopathological features. There were found to be statistical differences in postoperative outcomes in the type of gastrectomy and type of anastomosis (p<0.001 and p<0.001, respectively). In terms of overall survival analysis, there was no statistical survival difference among the subtypes of advanced gastric cancer (p=0.088). However, LELC had a better prognosis than the other groups. CONCLUSIONS: There were some differences in several of the clinicopathological features of the subtypes advanced gastric cancer. Although there were no statistical differences in survival, those with LELC showed a better prognosis than did the other groups. Therefore, the treatment of advanced gastric cancer should be individualized, and prognosis considered, according to the subtype.

Light shutter using dichroic-dye-doped long-pitch cholesteric liquid crystals.

We propose a light shutter device using dichroic-dye-doped liquid crystals (LCs) whose Bragg reflection wavelength is set to be infrared by controlling the pitch of cholesteric liquid crystals (ChLCs). A dye-doped long-pitch ChLC cell is switchable between the dark planar state and the transparent homeotropic state. It has the advantages of high transmittance, low operation voltage, and an easy fabrication process relative to previous LC light shutter devices. The proposed light shutter device is expected to achieve high visibility for transparent organic light-emitting diode displays and emerging smart windows, which can be used in airplanes, cars, and other similar applications.

Association between phosphorylated AMP-activated protein kinase and MAPK3/1 expression and prognosis for patients with gastric cancer.

OBJECTIVES: Phosphorylated AMP-activated protein kinase (pAMPK) plays a central role in cellular metabolic sensing and energy balance homeostasis, and interacts with various pathways [e.g., TP53, mTOR, NUAK2 (sucrose nonfermenting-like kinase), MAPK3/1 (ERK) and PDK]. Therefore, the present study analyzed the expression of pAMPK, NUAK2, MAPK3/1 and PDK-1 and their effect on the survival of patients with resected gastric cancer. METHODS: A total of 621 patients with gastric adenocarcinoma surgically resected with curative intent were enrolled in the study. Immunohistochemical staining for pAMPK, NUAK2, MAPK3/1 and PDK-1 was performed using tissue microarrays of surgical specimens of gastric cancer tissue. RESULTS: Positive pAMPK, NUAK2, MAPK3/1 and PDK-1 expression was observed in 379 (61.0%), 257 (41.4%), 327 (52.7%) and 67 (10.8%) cases, respectively. Multivariate survival analysis showed a significantly better survival for the patients with positive pAMPK or MAPK3/1 expression than for the patients with a negative expression [pAMPK: disease-free survival (DFS), hazard ratio (HR) = 0.750, 95% confidence interval (CI) = 0.568-0.970, p = 0.030; MAPK3/1: DFS, HR = 0.692, 95% CI = 0.720-0.974, p = 0.021), while NUAK2 or PDK-1 expression had no effect on survival. CONCLUSION: pAMPK or MAPK3/1 expression was found to be an independent prognostic marker for patients with resected gastric cancer.

Prognostic significance of neutrophil lymphocyte ratio and platelet lymphocyte ratio in advanced gastric cancer patients treated with FOLFOX chemotherapy.

BACKGROUND: Several inflammatory response materials could be used for prediction of prognosis of cancer patients. The neutrophil lymphocyte ratio (NLR), and the platelet lymphocyte ratio (PLR) have been introduced for prognostic scoring system in various cancers. The objective of this study was to determine whether the NLR or the PLR would predict the clinical outcomes in advanced gastric cancer patients treated with oxaliplatin/ 5-fluorouracil (FOLFOX). METHODS: The study population consisted of 174 advanced gastric cancer patients. Patients were treated with 85 mg/m2 of oxaliplatin as a 2-h infusion at day 1 plus 20 mg/m2 of leucovorin over 10 min, followed by 5-FU bolus 400 mg/m2 and 22-h continuous infusion of 600 mg/m2 at days 1-2. Treatment was repeated in 2-week intervals. The NLR and PLR were calculated from complete blood counts in laboratory test before and after first cycle of chemotherapy. RESULTS: NLR was a useful prognostic biomarker for predicting inferior overall survival (OS) (p = 0.005), but was not associated with progression free survival (PFS) (p = 0.461). The normalization of NLR after one cycle of chemotherapy was found to be in association with significant improvement in PFS (5.3 months vs. 2.4 months, p < 0.001), and OS (11.9 months vs. 4.6 months, p < 0.001). The normalization of PLR was also associated with longer PFS (5.6 months vs. 3.4 months, p = 0.006), and OS (16.9 months vs. 10.9 months, p = 0.002). In multivariate analysis, changes in NLR were associated with PFS (Hazard ratio (HR): 2.297, 95% confidence interval (CI): 1.429-3.693, p = 0.001). The NLR, (HR: 0.245, 95% CI: 0.092-0.633, p = 0.004), PLR (HR: 0.347, 95% CI: 0.142-0.847, p = 0.020), changes in NLR (HR: 2.468, 95% CI: 1.567-3.886, p < 0.001), and changes in PLR (HR: 1.473, 95% CI: 1.038-2.090, p = 0.030) were independent prognostic markers for OS. CONCLUSION: This study demonstrates that NLR, PLR, and changes in NLR or PLR are independent prognostic factor for OS in patients with advanced gastric cancer treated with chemotherapy. These specific factors may also help in identifying the patients, who are more sensitive to FOLFOX regimen.

In-plane switching of vertically aligned negative liquid crystals for high transmittance and wide viewing angle.

We propose a method for in-plane switching of vertically aligned negative liquid crystals (LCs) for high transmittance and wide viewing angle. By applying an in-plane electric field using a double-layered electrode structure, LC molecules can be rotated by the vertical as well as the in-plane components of the applied field over the entire region so that high transmittance can be achieved. The threshold voltage difference can be obtained simply by varying the electrode structure, which can reduce the off-axis gamma shift in a multidomain vertical alignment LC cell.

Is laparoscopy-assisted total gastrectomy feasible for the treatment of gastric cancer? A case-matched study.

BACKGROUND: The aim of this study was to clarify the short- and long-term outcomes of laparoscopy-assisted total gastrectomy (LATG) for gastric cancer compared to conventional open total gastrectomy (COTG) with a case-control study. METHODS: Between January 2002 and December 2010, a series of 264 patients with gastric cancer underwent R0 total gastrectomy (61 LATG patients and 203 COTG patients). Age, gender, and pathological stage were matched by propensity scoring, and 120 patients (60 LATG and 60 COTG) were selected for analysis. RESULTS: There were no significant differences in the clinicopathological features between the two groups. Regarding postoperative outcomes, first flatus time was significantly shorter in the LATG group than in the COTG group (p < 0.001), while operation time was significantly longer in the LATG group than in the COTG group (p < 0.001). Postoperative complications occurred in 5 cases (8.3%) of the LATG group and in 11 cases (18.3%) of the COTG group (p = 0.178). There were two recurrences in the LATG group and three recurrences in the COTG group. There was no significant difference in the 5-year survival rate between the two groups (p = 0.667). CONCLUSIONS: LATG for gastric cancer may be both feasible and efficient compared to COTG for experienced laparoscopic surgeons. This study is valuable for a prospective randomized controlled trial of LATG for gastric cancer in a larger number of patients.

Amorphous ITZO-Based Selector Device for Memristor Crossbar Array.

In the era of digital transformation, a memristor and memristive circuit can provide an advanced computer architecture that efficiently processes a vast quantity of data. With the unique characteristic of memristor, a memristive crossbar array has been utilized for realization of nonvolatile memory, logic-in-memory circuit, and neuromorphic system. However, the crossbar array architecture suffers from leakage of current, known as the sneak current, which causes a cross-talk interference problem between adjacent memristor devices, leading to an unavoidable operational error and high power consumption. Here, we present an amorphous In-Sn-Zn-O (a-ITZO) oxide semiconductor-based selector device to address the sneak current issue. The a-ITZO-selector device is realized with the back-to-back Schottky diode with nonlinear current-voltage (I-V) characteristics. Its nonlinearity is dependent on the oxygen plasma treatment process which can suppress the surface electron accumulation layer arising on the a-ITZO surface. The a-ITZO-selector device shows reliable characteristics against electrical stress and high temperature. In addition, the selector device allows for a stable read margin over 1 Mbit of memristor crossbar array. The findings may offer a feasible solution for the development of a high-density memristor crossbar array.

A 5 year analysis of readmissions after radical subtotal gastrectomy for early gastric cancer.

BACKGROUND: Many patients and surgeons have become interested in the quality of life after surgery for early gastric cancer. However, no reports on readmission rates for gastrectomy patients have been published, even if readmission greatly affects the patient's quality of life. METHODS: In 530 consecutive early gastric cancer patients who underwent radical subtotal gastrectomy, we determined the incidence, cause, timing, type of treatment, and risk factors for readmission after discharge, and compared the readmission and nonreadmission groups with respect to clinicopathologic features and postoperative outcomes. RESULTS: Overall, the 5 year and 1 month readmission rates after radical subtotal gastrectomy for early gastric cancer were 13.0% (69 of 530) and 7.5% (40 of 530), respectively. The most common cause for readmission was delayed gastric emptying (17 cases). Among a total of 82 readmissions, 34 patients (41.5%) were readmitted within 2 weeks of surgery. The type of treatment for 82 readmissions included 55 conservative therapies, 15 radiologic or endoscopic interventions, and 12 repeat laparotomies. No significant differences were detected in the clinicopathologic feature and postoperative outcomes between the two groups. The initial hospital stay remained significantly associated with readmission based on multivariate analysis. CONCLUSIONS: Readmission rate at 1 month after radical subtotal gastrectomy is lower than that after major bowel surgery. Unusual postoperative recovery in a patient with vague symptoms should be managed with greater care before discharge. After subtotal gastrectomy for early gastric cancer, prevention of readmission can improve the patient's quality of life.

Dual mode switching of cholesteric liquid crystal device with three-terminal electrode structure.

We propose a cholesteric liquid crystal device with a three-terminal electrode structure that can be operated in both the dynamic and the bistable modes. Fast switching (less than 5 ms) between the planar and the in-plane-field-induced states can be realized by applying an in-plane electric field, and conventional bistable switching between the planar and focal conic states can be realized by applying a vertical electric field.

Ultrafast switching of randomly-aligned nematic liquid crystals.

We propose an ultrafast nematic liquid crystal (LC) device without alignment layers, where both the dark and bright states can be realized by applying an electric field. A vertical electric field is applied to vertically align the LCs for the dark state, whereas an in-plane electric field is applied to homogeneously align the LCs for the bright state. We achieved a total response time of less than 3 ms in the proposed device. This device may contribute, not only to a significant improvement of the switching speed in liquid crystal devices, but also to the simplification of the device fabrication by the omission of the alignment layer coating and the rubbing process.

Anastomosis by use of compression anastomosis ring (CAR™ 27) in laparoscopic surgery for left-sided colonic tumor.

PURPOSE: The safety and efficacy of the compression anastomosis ring (CAR™ 27) had been demonstrated by animal studies. This study was designed to evaluate clinical validity of the CAR™ 27 anastomosis in laparoscopic surgery for patients with left-sided colonic neoplasm. METHODS: Intracorporeal anastomosis using the CAR™ 27 (CAR group) was performed in 66 patients (male 35; median age, 64.5 years), and short-term results were compared with consecutive 116 patients (male 70; median age, 64 years) where the anastomosis was constructed by double stapling technique using a circular stapler for the same indications (stapled group). RESULTS: There were no statistically significant differences between the two groups in terms of gender, age, and distribution of pathologic lesion. The laparoscopic procedures, pathologic diagnosis/stage, and length of operation time and postoperative hospital stay were comparable between the two groups. Conversion rate in the CAR and stapled group was 3% and 6%, respectively. There was no surgical mortality in either group. No intraoperative complications associated with the CAR™ 27 anastomosis were encountered. One patient in the CAR group was complicated by anastomotic leakage and none in the stapled group (p = 0.36). There was intestinal obstruction in two patients, in whom one required re-operation for entrapped small bowel adhesions within pelvis. No patient in either group showed symptomatic anastomotic stricture. CONCLUSIONS: The anastomosis using the CAR™ 27 is an innovative technique. The CAR™ 27 anastomosis in patients undergoing laparoscopic colectomy for left-sided colonic tumor proved to be a safe and efficacious alternative to the standard double stapling technique.

Fascin expression is related to poor survival in gastric cancer.

Fascin is an actin-binding protein that provides mechanical support and cell motility, and involves cancer cell metastasis. We investigated fascin protein expression in gastric cancer and assessed their relationship with clinicopathologic parameters and survival rates. In addition, we researched galectin-3 protein expression to study fascin action mechanisms. We performed immunohistochemisty with fascin and galectin-3 antibodies in 471 gastric carcinomas, using tissue microarrays. Fascin was positive in 14.9% (70/471) of the samples, and fascin expression was related to worse survival rates (P < 0.001), high clinical stage (P < 0.001), high T stage (P < 0.001), nodal metastasis (P < 0.001), lymphovascular invasion (P= 0.001) and the intestinal type of Lauren classification (P= 0.015). Galectin-3 protein expression was positive in 83.9% (395/471) of the samples and was reversely correlated with fascin protein expression (P= 0.020). Galectin-3 expression was related to low clinical stage (P < 0.001), but not to survival rates in multivariate analysis. In multivariate analysis, fascin expression was related to worse survival rates (HR = 1.56, P= 0.036), and can be an independent poor prognostic factor in gastric cancer.

Long memory retention time and high contrast ratio in a tristate liquid crystal display device.

We propose a method to obtain long memory retention time and high contrast ratio in a tristate liquid crystal display device. The proposed device has three unique liquid crystal (LC) states that are known as splay, π twist, and bend, with different operating schemes for the two modes of operation, which are the memory (M) mode or dynamic (D) mode. A form of selective vertical or horizontal switching changes the optically compensated π twist LC as a common black state in both the M and D modes into a bend LC state for the D mode or into the splay LC state for the M mode, respectively.

Comparative analysis of five-year survival results of laparoscopy-assisted gastrectomy versus open gastrectomy for advanced gastric cancer: a case-control study using a propensity score method.

BACKGROUND: The aim of this study was to investigate the surgical and oncologic outcomes of laparoscopy-assisted gastrectomy (LAG) and open gastrectomy (OG) for advanced gastric cancer (AGC) using the case-control method with a sufficient follow-up period. PATIENTS AND METHODS: The authors retrospectively analyzed 89 patients who underwent LAG and 345 patients who underwent OG for AGC between August 1999 and June 2007. A total of 176 matched cases were included in the final analysis. RESULTS: Except for tumor size and reconstruction, there were no statistically significant differences in the clinicopathological parameters between the two groups. Although operation time was significantly longer for LAG than OG (228.3 vs. 183.6 min, p < 0.0001), first flatus time and postoperative hospital stay without complications were significantly shorter in the LAG group (3.2 vs. 3.7 days, p < 0.0001; 7.0 vs. 10.4 days, p < 0.0001, respectively). Operation-related complications occurred in 7 cases (8.0%) in both groups. 13 patients (14.8%) in the LAG group and 15 patients (17.1%) in the OG group had recurrence. There was no statistically significant difference in the 5-year and disease-free survival rates between LAG and OG. CONCLUSIONS: LAG for AGC might be considered to be a minimally invasive surgery in some selected cases, although a well-designed prospective study comparing LAG with OG for AGC is needed.

Long term survival results for gastric GIST: is laparoscopic surgery for large gastric GIST feasible?

BACKGROUND: Recently, laparoscopic resection for relatively small sized gastric gastrointestinal stromal tumors (GISTs) has been widely accepted as minimally invasive surgery. However, no report on the long-term safety and efficacy of this surgery for large sized gastric GISTs has been published to date. METHODS: Between July 1998 and January 2011, 104 consecutive patients who underwent resection for gastric GISTs were enrolled in this retrospective study. We assessed the clinicopathological characteristics, postoperative outcomes, patient survival, and tumor recurrence. RESULTS: Of the 104 patients with gastric GISTs who were included in the study, there were 47 males and 57 females whose mean age was 59.8 years. Sixty-four patients (61.5%) had symptoms associated with tumor. Ten patients included in the group 1, 49 in the group 2, 15 in the group 3a, 9 in the group 5, 14 in the group 6a, and 7 in the group 6b. There was one minor complication and no mortalities. Recurrence was noted in 5 patients, with a median follow-up period of 49.3 months (range, 8.4 to 164.4). The 5-year overall and disease free survival rates of 104 patients were 98.6% and 94.8%, respectively. When comparing large tumor (5-10 cm) between laparoscopic and open surgery, there were statistically differences in age, tumor size, tumor location, and length of hospitalization. There were no statistical differences in the 5-year survival rate between laparoscopic and open surgery for large tumor (5-10cm). CONCLUSION: Laparoscopic surgery is feasible and effective as an oncologic treatment of gastric GISTs. Moreover, laparoscopic surgery can be an acceptable alternative to open methods for gastric GISTs of size bigger than 5 cm.

Early experience of laparoscopic resection and comparison with open surgery for gastric gastrointestinal stromal tumor: a multicenter retrospective study.

The advantages of laparoscopic resection over open surgery in the treatment of gastric gastrointestinal stromal tumor (GIST) are not conclusive. This study aimed to evaluate the postoperative and oncologic outcome of laparoscopic resection for gastric GIST, compared to open surgery. We retrospectively reviewed the prospectively collected database of 1019 patients with gastric GIST after surgical resection at 13 Korean and 2 Japanese institutions. The surgical and oncologic outcomes were compared between laparoscopic and open group, through 1:1 propensity score matching (PSM). The laparoscopic group (N = 318) had a lower rate of overall complications (3.5% vs. 7.9%, P = 0.024) and wound complications (0.6% vs. 3.1%, P = 0.037), shorter hospitalization days (6.68 ± 4.99 vs. 8.79 ± 6.50, P < 0.001) than the open group (N = 318). The superiority of the laparoscopic approach was also demonstrated in patients with tumors larger than 5 cm, and at unfavorable locations. The recurrence-free survival was not different between the two groups, regardless of tumor size, locational favorableness, and risk classifications. Cox regression analysis revealed that tumor size larger than 5 cm, higher mitotic count, R1 resection, and tumor rupture during surgery were independent risk factors for recurrence. Laparoscopic surgery provides lower rates of complications and shorter hospitalizations for patients with gastric GIST than open surgery.

Single cell-gap transflective liquid crystal device created by controlling the pretilt angle using a liquid crystalline reactive monomer.

We present a single cell-gap transflective liquid crystal (LC) device using a homogeneous alignment polyimide (H-PI) mixed with a liquid crystalline reactive monomer that is able to vertically align the LC. We obtain two different pretilt angles in each pixel through the region by region control of the UV exposure time. The smaller pretilt angle is used to obtain a half-wave phase retardation for the transmissive part, whereas the larger pretilt angle is used to obtain a quarter-wave phase retardation for the reflective part.