Progress in a selective method for the determination of the acetaldehyde-derived DNA adducts by using HILIC-ESI-MS/MS

Acetaldehyde (AA), which is present in tobacco smoke, automobile exhaust gases and alcohol beverage, is a mutagen and carcinogen. AA reacts with 2'-deoxyguanosine (dG) in DNA to form N²-ethyl-dG (EtdG) and cyclic, 1, N²-propano-dG (CPrdG), which are considered to have a critical role in carcinogenesis induced by AA. In this study, we have developed a highly sensitive method for the quantitation of the two AA-derived DNA adducts by using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) in which hydrophilic interaction chromatography (HILIC) employing mobile phases of high organic solvent concentration was selected to improve the ionization efficiency in the ESI process. Fourteen times and 11 times larger peak areas for EtdG and CPrdG, respectively, in HILIC-ESI-MS/MS were obtained compared with those in reversed phase (RP)-LC-ESI-MS/MS. Furthermore, 6.9 times (for EtdG) and 2.4 times (for CPrdG) larger peak areas were also obtained as additional enhancement by varying additive compounds in the HILIC mobile phases from ammonium acetate to ammonium bicarbonate. In total, the enhancements in detected MS signal intensities by exchanging from the RP-LC system to the HILIC system are 97 times for EtdG and 26 times for CPrdG, respectively. Three commercially available HILIC columns with different polar functional groups were examined and sufficient separation between normal 2'-deoxynucleosides and the AA-derived DNA adducts was achieved by a carbamoyl-bonded HILIC column. Finally, we applied the established method to quantify EtdG and CPrdG in the damaged calf thymus DNA.

Endoscopic treatment outcomes of laterally spreading tumors with a skirt (with video)

BACKGROUND AND AIMS

A "skirt" is a slightly elevated flat lesion with wide pits occasionally observed at the margin of laterally spreading tumors (LSTs). However, the endoscopic treatment outcomes of LSTs with skirts have not been clarified. The aim of this study was to evaluate the endoscopic treatment outcomes of LSTs with skirts.

METHODS

Between February 2006 and March 2014, 996 LSTs were retrospectively examined to assess the clinicopathologic characteristics, procedure time, en bloc resection rate, R0 resection rate, adverse events, and local recurrence rate of endoscopic submucosal dissection (ESD) and of endoscopic resection.

RESULTS

Endoscopic treatment was performed in 35 cases of LSTs with skirts (ratio of ESD to endoscopic piecemeal mucosal resection [EPMR], 32:3) and 961 cases of LSTs without skirts (ratio of ESD to EMR to EPMR to polypectomy, 381:275:114:191). LSTs with a skirt were associated with a significantly higher recurrence rate (P < .01). In both ESD and EPMR, LSTs with a skirt were associated with a higher recurrence rate when compared with LSTs without a skirt (odds ratio, 12.7; P = .032, and odds ratio, 12.3; P = .061, respectively). Multivariate analysis demonstrated that the presence of the skirt and piecemeal resection were significant predictors of local recurrence.

CONCLUSIONS

LSTs with skirts had a significantly higher local recurrence rate after endoscopic treatment compared with LSTs without skirts, especially after EPMR. Therefore, ESD should be recommended as an endoscopic treatment for LSTs with skirts to minimize local recurrence.

Prospective trial of biodegradable stents for refractory benign esophageal strictures after curative treatment of esophageal cancer

BACKGROUND AND AIMS

Biodegradable stents are reportedly effective for refractory benign esophageal strictures; however, little is known about their use in patients with refractory stricture after endoscopic submucosal dissection (ESD) or chemoradiotherapy (CRT) for esophageal cancer. This study aimed to evaluate the effectiveness of biodegradable stents for these patients.

METHODS

Patients with refractory benign esophageal stricture with a dysphagia score (DS) of 2 or worse and for whom the passage of a standard size endoscope was not possible were eligible. The primary endpoint was the proportion of those who improved their DSs (% DS improved) at 12 weeks after stent placement, and the secondary endpoints were the proportion of those who improved their DSs at 24 weeks, dysphagia-free survival (DFS), and adverse events.

RESULTS

Eighteen patients (men:women, 15:3; median age, 72 years; range, 53-80) were enrolled. Twelve patients improved their DS at 12 weeks (% DS improved, 66.7%; 90% CI, 44.6%-84.4%). Also, 8 of 11 patients (72.7%) after esophagectomy, 4 of 6 patients (66.7%) after ESD, and 3 of 4 patients (75%) after CRT improved at 12 weeks. Three patients who were treated with esophagectomy maintained their DS improvement at 24 weeks (% DS improved, 16.7%; 95% CI, 3.6%-41.4%). The median DFS was 14.1 weeks (95% CI, 13.0-19.0). One patient who had ESD and CRT developed an esophagobronchial fistula 3 months after stent placement.

CONCLUSIONS

Biodegradable stents are effective and tolerable for refractory benign esophageal strictures after treatment for esophageal cancer; however, long-term efficacy was limited, especially after ESD or CRT. (Clinical trial registration number: UMIN000008054.).

Detectability of colorectal neoplastic lesions using a novel endoscopic system with blue laser imaging: a multicenter randomized controlled trial

BACKGROUND AND AIMS

Most studies have not reported an improvement in the detection of adenomas with the use of image-enhanced colonoscopy methods, possibly because of the darkness of the images. To overcome this limitation, a new-generation endoscopic system has been developed. This system has 2 blue-laser imaging (BLI) observation modes. The BLI observation was set to BLI-bright mode to detect lesions. We aimed to evaluate the efficacy of BLI in detecting lesions.

METHODS

This study was designed as a randomized controlled trial with participants from 8 institutions. We enrolled patients aged ≥40 years. The participants were randomly assigned to 2 groups: observation by using white-light imaging (WLI) with a conventional xenon light source (WLI group) or observation by using BLI-bright mode with a laser light source (BLI group). All of the detected lesions were resected or had a biopsy taken for histopathologic analysis. The primary outcome was the mean number of adenomas per patient (MAP) that were detected per procedure.

RESULTS

The WLI and BLI groups consisted of 474 and 489 patients, respectively. The MAP was significantly higher in the BLI group than in the WLI group (mean ± standard deviation [SD] WLI 1.01 ± 1.36, BLI 1.27 ± 1.73; P = .008). Adenoma detection rate in the BLI group was not significantly higher than in the WLI group. Observation times differed significantly, with BLI (9.48 minutes) being longer than WLI (8.42; P < .001). The mean (± SD) number of polyps per patient was significantly higher in the BLI group compared with the WLI group (WLI 1.43 ± 1.64, BLI 1.84 ± 2.09; P = .001).

CONCLUSIONS

A newly developed system that uses BLI improves the detection of adenomatous lesions compared with WLI. (Clinical trial registration number: UMIN 000014555.).

Alcohol abstinence and risk assessment for second esophageal cancer in Japanese men after mucosectomy for early esophageal cancer

BACKGROUND

Alcohol consumption combined with inactive aldehyde dehydrogenase-2 (ALDH2) and the presence of multiple esophageal Lugol-voiding lesions (LVLs; dysplasia) are strong predictors for multiple development of esophageal squamous cell carcinoma (ESCC) in East Asians. We invented a health risk appraisal (HRA) model for predicting the risk of ESCC based on drinking, smoking, dietary habits, and alcohol flushing, i.e., past or present facial flushing after drinking a glass of beer, a surrogate marker for inactive ALDH2.

METHODS

Prospective follow-up examinations (median follow-up time, 50.3 months) were performed in 278 Japanese men after endoscopic mucosectomy for early ESCC (UMIN Clinical Trials Registry ID: UMIN000001676).

RESULTS

Sixty-four subjects developed metachronous ESCC. A receiver operating characteristic curve showed that HRA scores ≥12 best predicted the development of metachronous ESCC. The ESCC detection rate per 100 person-years was 9.8 in the high-HRA-score group (n = 104) and 4.5 in the low-HRA-score group (n = 174), and the risk of development of metachronous ESCC was higher in the high-HRA-score group than in the low-HRA-score group (adjusted hazard ratio: 2.00 [95% CI: 1.12-3.30]). Multiple LVLs was a very strong predictor of the development of metachronous SCC, but high HRA scores predicted it independently. The cumulative incidences of metachronous ESCC decreased after drinking cessation in the high-HRA-score drinker group (adjusted hazard ratio: 0.37 [0.14-0.97]).

CONCLUSIONS

Both the HRA model that included alcohol flushing and the multiple LVL grade predicted the development of metachronous ESCC in Japanese men after endoscopic mucosectomy for ESCC. Drinking cessation in the high-HRA-score drinker group reduced the rate of metachronous ESCC.

Evaluation of cellular purine transport and metabolism in the Caco-2 cell using comprehensive high-performance liquid chromatography method for analysis of purines

Using Caco-2 cells and our previously developed high-performance liquid chromatography method for quantification of purine bases, nucleosides, and nucleotides, we evaluated cellular purine transport and uptake. The analytes were separated using YMC-Triart C18 column with gradient elution. We used Caco-2 cells as intestinal model cells and monitored purine transport across a monolayer for 2 h. The degree of change of purine concentrations in the permeate was very slight; however, it was possible to simultaneously determine these parameters for all purines because of our method's high sensitivity. In the present study, the purine bases (adenine, guanine, hypoxanthine, and xanthine) showed a relatively high permeability as compared with the nucleosides (adenosine, guanosine, inosine, and xanthosine). Increased concentration of metabolites in the permeate was also observed following the addition of purines. In a cell uptake assay, both the cell culture medium (extracellular) and the cells extracted from Caco-2 with acetonitrile:water (7:3) (intracellular) were measured. The additional nucleoside did not increase significantly within the cells. On the other hand, we observed that nucleotide, such as ATP, increased in the cell in a time-dependent manner following the addition of nucleoside. The additional nucleosides were considered to be rather recycled via the salvage pathway than metabolized to purine bases and/or uric acid in the cell. Such differences might have affected the increase in the serum uric acid levels depending on purine form.

Urinary excretion of uric acid, allantoin, and 8-OH-Deoxyguanosine in uricase-knockout mice

Although uricase-knockout (Uox KO) mice are reported to develop uric acid (UA) nephropathy, those that mature without severe nephropathy could be useful for research into purine metabolism in humans. In this study, we measured the urinary excretion of creatinine, UA, allantoin, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) collected from Uox KO mice housed in metabolic cages. UA and allantoin were determined using liquid chromatography-mass spectrometry and creatinine and 8-OHdG were measured with a commercial kit. Uox KO mice excreted significantly higher levels of UA than wild-type mice (C57BL/6), while the excretion of allantoin was significantly lower. Urinary allantoin was detected in Uox KO mice despite a lack of uricase, which is the same as in humans. In contrast to the elevated levels of UA, the daily excretion of 8-OHdG, an oxidative stress marker, was lower in Uox KO mice. UA is thought to act as an anti-oxidizing agent in humans; thus, these results show that Uox KO mice are potential animal models for research into human purine metabolism.

Evaluation of purine utilization by Lactobacillus gasseri strains with potential to decrease the absorption of food-derived purines in the human intestine

It is well accepted that frequent and heavy intake of purine-rich foods causes elevation of serum uric acid levels, which is a risk factor of hyperuricemia. Reducing intestinal absorption of dietary purines may attenuate the elevation of serum uric acid levels and exacerbation of hyperuricemia. This reduction may be achieved by the ingestion of lactic acid bacteria that take up purines in the intestine. In this study, we investigated the degree of uptake and utilization of purines of three lactobacilli strains. Among them, Lactobacillus gasseri PA-3 (PA-3) showed the greatest incorporation of ¹⁴C-adenine. PA-3 also incorporated ¹⁴C-adenosine and ¹⁴C-AMP. Additionally, using defined growth medium, PA-3 demonstrated greater proliferation in the presence of these purines than in their absence. Although further investigation is required, ingestion of PA-3 may lower serum uric acid levels by reducing intestinal absorption of purines in humans.

Clinical impact of surveillance for head and neck cancer in patients with esophageal squamous cell carcinoma

AIM

To evaluate the clinical impact of surveillance for head and neck (HN) region with narrow band imaging (NBI) in patients with esophageal squamous cell carcinoma (ESCC).

METHODS

Since 2006, we introduced the surveillance for HN region using NBI for all patients with ESCC before treatment, and each follow-up. The patients with newly diagnosed stage I to III ESCC were enrolled and classified into two groups as follows: Group A (no surveillance for HN region); between 1992 and 2000), and Group B (surveillance for HN region with NBI; between 2006 and 2008). We comparatively evaluated the detection rate of superficial head and neck squamous cell carcinoma (HNSCC), and the serious events due to metachronous advanced HNSCC during the follow-up.

RESULTS

A total 561 patients (group A: 254, group B: 307) were enrolled. Synchronous superficial HNSCC was detected in 1 patient (0.3%) in group A, and in 12 (3.9%) in group B (P = 0.008). During the follow up period, metachronous HNSCC were detected in 10 patients (3.9%) in group A and in 30 patients (9.8%) in group B (P = 0.008). All metachronous lesions in group B were early stage, and 26 patients underwent local resection, however, 6 of 10 patients (60%) in group A lost their laryngeal function and died with metachronous HNSCC.

CONCLUSION

Surveillance for the HN region by using NBI endoscopy increase the detection rate of early HNSCC in patients with ESCC, and led to decrease serious events related to advanced metachronous HNSCC.

Predictive factors of residual tumor for the patients with non-curative resection after endoscopic submucosal dissection for early gastric cancer

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Background: Endoscopic submucosal dissection (ESD) is commonly performed for the patients who diagnosed with early gastric cancer. Although additional gastrectomy is recommended for the patients with non-curative ESD in the points of potential risk of residual tumor, many cases have neither lymph node (LN) metastasis nor local residual tumor in surgical specimens. Clinically, it can be difficult to decide whether to perform additional surgery according to patients’ conditions. This study aimed to analyze the clinicopathological features of patients who underwent additional gastrectomy as well as to detect the predictive factors for residual tumor after non-curative ESD. Methods: The patients who underwent additional gastrectomy after non-curative ESD in our institution from January 2005 to August 2016 were retrospectively reviewed. The incidence rates of LN metastasis or local residual tumor were calculated, and furthermore the predictive factors for these outcomes were estimated. Results: 211 patients were enrolled in this study. Pathological examination after additional surgery revealed LN metastasis in 18 patients (8.5%) and local residual tumor in 26 patients (12.3%). Multivariable analysis revealed that lymphatic invasion ( p< 0.0001, odds ratio = 15.6), vascular invasion ( p= 0.042, odds ratio = 3.92) and macroscopic findings (flat/elevated type) ( p= 0.03, odds ratio = 3.53) are predictors for lymph node metastasis. All of the patients without LN metastasis revealed no lymphovascular invasion. Positive vertical margin ( p= 0.0045, odds ratio = 4.17) and horizontal margin ( p= 0.0002, odds ratio = 6.6) were predictors for local residual tumor. Conclusions: The risk of residual tumor can be estimated based on histopathology of ESD. Patients without lymphovascular invasion appear to be a low risk subpopulation for LN metastasis.

Risk factors for intraoperative perforation during endoscopic submucosal dissection of superficial esophageal squamous cell carcinoma

AIM

To identify the risk factors and clarify the subsequent clinical courses.

METHODS

This study retrospectively analyzed consecutive patients with esophageal squamous cell carcinoma (ESCC) treated using endoscopic submucosal dissection (ESD) between April 2008 and October 2012. We divided the ESCC lesions into perforation cases and non-perforation cases, and compared characteristics and endoscopic findings between the two groups. "Intraoperative perforation" was defined as the detection of a perforation site during ESD and the presence of mediastinal emphysema.

RESULTS

In total, 147 patients with 156 ESCC lesions were treated by ESD. Intraoperative perforation was recorded for nine lesions (5.8%) from nine patients. Multivariate analysis identified mucosal deficiency larger than 75% of the circumference of the esophagus as an independent risk factor for intraoperative perforation (OR = 7.37, 95%CI: 1.45-37.4, P = 0.016). The predominant site of perforation was the left wall [6/9 (67%)]. Six of nine perforation sites were successfully closed by clips during the procedures. Two of nine cases required drainage for pleural effusions; however, all nine cases recovered with conservative treatment and without surgical intervention. At the median follow up of 42 mo after ESD, no cases of local recurrence or distant organ metastasis had been observed.

CONCLUSION

This study suggests that mucosal deficiency larger than 75% of the luminal circumference is a risk factor for intraoperative perforation during ESD for ESCC.

Pharmacokinetic evaluation of intrapleural perfusion with hyperthermic chemotherapy using cisplatin in patients with malignant pleural effusion

OBJECTIVES

Malignant pleural effusion (MPE) has a poor prognosis. Most patients are treated with tube thoracostomy and sclerotherapy, although its success rate is around 64%. We have investigated intrapleural perfusion with hyperthermic chemotherapy (IPHC) using cisplatin in a study with a pharmacokinetic evaluation.

METHODS

Patients with MPE, performance status of 0-1, possibility of good lung expansion and Cr<1.2mg/dL were treated with IPHC. The circuit was filled with 2000mL of normal saline containing cisplatin at a dose of 80mg/m². Under video-assisted thoracoscopic surgery, the thoracic cavity was filled and perfused at a speed of approximately 1L/min at a temperature of 43°C for 1h. Perfusion solution and plasma samples were periodically collected, and concentrations of protein-unbound (free) platinum, which was the active derivative of cisplatin, and total platinum were determined by flameless atomic absorption spectrometry.

RESULTS

Twenty patients with MPE (8 lung cancers, 7 mesotheliomas, and 5 others) were enrolled in this study. Rate of free platinum concentration relative to total platinum concentration in perfusion solution after 1hr IPHC at 43°C was 61.1±12.9%. Area under curve (AUC) of free platinum in the pleural space was calculated to be 26.3μg/mLxh, resulting in complete control of pleural effusion for 3 months after IHPC in all cases (95% confidence interval: 83-100%). While, absorption rate of total platinum from the pleural space was 33.8±17.0% (27.4±13.6mg/m²), and the maximum concentration of total platinum in serum was low, 0.66±0.31μg/mL, resulting in controllable side effects; grade 1 renal toxicity: 6 patients, grade 1 emesis: 7 patients.

CONCLUSIONS

IPHC with cisplatin showed favorable pharmacokinetic profiles for an optional treatment to control malignant pleural effusion.

Adenocarcinoma arising from heterotopic gastric mucosa in the cervical esophagus and upper thoracic esophagus: two case reports and literature review

Primary adenocarcinoma arising from heterotopic gastric mucosa (HGM) is rare and the clinicopathological characteristics are not well known. We present two cases of esophageal adenocarcinoma arising from HGM with a review of a case series. Case 1 was a 78-year-old woman who underwent a periodic medical examination without complaining of any symptoms. Preoperative evaluation suggested esophageal adenocarcinoma arising from the HGM. The patient was treated with endoscopic submucosal dissection. Definitive pathological diagnosis confirmed adenocarcinoma arising from the HGM. Case 2 was a 70-year-old man who underwent a medical examination after complaining of dysphagia. Preoperative diagnosis suggested esophageal adenocarcinoma; however, its origin was unclear. The patient was treated with surgical resection. Definitive pathological diagnosis revealed adenocarcinoma arising from the HGM. In this article, the authors report the clinicopathological features of esophageal adenocarcinoma arising from HGM that were collected from a literature review and our cases.

Prophylactic steroid administration for strictures after endoscopic resection of large superficial esophageal squamous cell carcinoma

Background and study aims: One of the major complications after endoscopic resection (ER) for large superficial esophageal squamous cell carcinoma (ESCC) is benign esophageal stricture, which can reduce quality of life even if ESCC achieves a cure without organ resection. Recently, steroid administration has been reported as a prophylactic treatment to prevent esophageal strictures. This retrospective study evaluated the stricture rate according to the different width of mucosal defects due to ER and compared it to that seen with prophylactic steroid administration. Patients and methods: Between June 2007 and December 2013, we enrolled patients with ESCC who had 3/4 or larger circumferential mucosal defects due to ER. In December 2009, steroid injections (triamcinolone acetonide 50 mg) into the ulcer bed due to ER were introduced. Beginning in November 2012, we commenced oral steroid administration (prednisolone 30 mg/day, tapered gradually for 8 weeks) in addition to steroid injection. Patients were classified into 3 groups according to the width of mucosal defect after ER (Group A, ≥ 3/4 and < 7/8; Group B, ≥ 7/8 and less than the entire circumference; and Group C, the entire circumference). We retrospectively evaluated the stricture rate by comparing no treatment, steroid injection, or steroid injection followed by oral steroid according to the width of mucosal defect. Results: A total of 115 patients met the selection criteria. In Group B, no treatment had a significantly higher stricture rate (100 %, vs. steroid injection: 56 % P = 0.015; vs steroid injection followed by oral steroid: 20 % P < 0.001). Conversely, in Group C, the stricture rate was high, regardless of treatment (no treatment: 100 %; steroid injection: 100 %; steroid injection followed by oral steroid: 71 %). Conclusions: Although prophylactic steroid administration is effective to prevent strictures for 7/8 circumference or larger mucosal defects, it is ineffective for whole-circumference defects. Further investigation is required.