The Effect of Hyperbaric Oxygen Therapy on Rectal Ulcers after Argon Plasma Coagulation

Chronic radiation proctitis usually develops 3 months after therapy. Despite the lack of standard guidelines regarding treatment, argon plasma coagulation is often a safe and effective endoscopic therapy. However, rectal ulcers are a common complication after argon plasma coagulation. Nevertheless, most patients are asymptomatic and do not require additional monitoring or treatment. We report a case of an argon plasma coagulation-induced ulcer with relevant symptoms and refractory to medical treatment. The patient was treated with hyperbaric oxygen therapy and had complete resolution of the rectal ulcer. Hyperbaric oxygen therapy has shown efficacy in severe chronic proctitis and radiation-induced rectal ulcers, but no clinical report has ever been published on using hyperbaric oxygen therapy for ulcers after argon plasma coagulation. In this case, hyperbaric oxygen therapy was an effective alternative option and can be considered in patients with refractory argon plasma coagulation-induced rectal ulcers.

Endoscopic Submucosal Dissection of Gastric Superficial Lesions: Predictors for Time of Procedure in a Portuguese Center

BACKGROUND

Endoscopic submucosal dissection (ESD), an endoscopic technique used for treatment of gastric superficial lesions, has been gaining importance on western countries. Procedural times have an impact on various outcomes.

AIM

To define which factors from patients, lesions and procedure can predict longer procedural times.

METHODS

In a cohort of 127 lesions resected by ESD with IT-knife, after using needle-knife for submucosal layer access, by experienced gastroenterologists, characteristics from the patient (age, gender, presence of co-morbidities, usage and suspension of anti-platelet drugs and general physical condition), lesion (size, histopathological diagnosis at biopsy, location, macroscopic type and submucosal invasion) and procedure (adverse events) were retrospectively analyzed for its impact on time of procedure. Univariate and multivariate analysis were performed.

RESULTS

Lesions larger than 20 mm (p < 0.001), on the upper third of the stomach (p = 0.035) and with an ASA score of 3 (p = 0.031) were considered influential factors for a longer procedure time and specifically for a time of procedure longer than 90 min. Existence of intra-procedure adverse events was also a predictor for a procedure time >90 min. Lesion's size >20 mm and location in the upper third were independently associated with a procedure time longer than 90 min (OR 4.91 [95%CI 2.29-10.50] and OR 18.26 [95%CI 2.02-164.78], respectively).

CONCLUSION

The time of procedure of ESD for gastric superficial lesions is influenced by size of lesion (>20 mm) and location (upper third of stomach), which predict a time longer than 90 min. This can be useful for better management of workflow, operation, training of teams and anesthesic procedures.

Long-term follow-up after endoscopic resection of gastric superficial neoplastic lesions in Portugal

BACKGROUND AND STUDY AIMS

Although endoscopic resection for the treatment of gastric superficial neoplastic lesions is an established first-line treatment in Eastern countries, its role has yet to be considered in Western guidelines, mostly due to a lack of long-term studies. The aim of this study was to describe long-term outcomes for endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) in the treatment of gastric neoplasias in Portugal.

PATIENTS AND METHODS

This was a single-center, retrospective, cohort study between March 2003 and April 2013. A total of 162 consecutive patients with 195 gastric superficial neoplasias underwent EMR (n = 54) or ESD (n = 141) and were followed up for a median of 3.2 years.

RESULTS

Resection was feasible in 97 %, with en bloc and R0 resection rates of 85 % (94 % ESD vs. 61 % EMR; P = 0.001) and 81 % (91 % ESD vs. 54 % EMR; P < 0.001), respectively. The recurrence rate was 7 %, and recurrence was associated with Rx/R1 resection irrespective of resection technique (OR 5.8; 95 % confidence interval 3.9 - 8.8). The long-term curative resection rate was 86 % after one procedure and 91 % after two procedures. Adverse events were observed in 13 % of cases: 8 % bleeding and 2 % of perforations (EMR = ESD). Surgery was performed in 7 %: 6 % after noncurative endoscopic resection and 1 % due to complications. Metachronous lesion detection rate was 1 % - 1.5 % per patient year. Cancer-specific survival rate was 100 % at follow-up.

CONCLUSIONS

For the first time in a Western country, results are reported to be similar to those in Eastern countries. Endoscopic resection, particularly ESD, is a highly effective treatment for gastric superficial lesions, without compromising cancer survival. Endoscopic resection should also be considered as first-line treatment for gastric neoplasias in Western countries.

The learning curve for narrow-band imaging in the diagnosis of precancerous gastric lesions by using Web-based video

BACKGROUND

A simplified narrow-band imaging (NBI) endoscopy classification of gastric precancerous and cancerous lesions was derived and validated in a multicenter study. This classification comes with the need for dissemination through adequate training.

OBJECTIVE

To address the learning curve of this classification by endoscopists with differing expertise and to assess the feasibility of a YouTube-based learning program to disseminate it.

DESIGN

Prospective study.

SETTING

Five centers.

PARTICIPANTS

Six gastroenterologists (3 trainees, 3 fully trained endoscopists [FTs]).

INTERVENTIONS

Twenty tests provided through a Web-based program containing 10 randomly ordered NBI videos of gastric mucosa were taken. Feedback was sent 7 days after every test submission.

MAIN OUTCOME MEASUREMENTS

Measures of accuracy of the NBI classification throughout the time.

RESULTS

From the first to the last 50 videos, a learning curve was observed with a 10% increase in global accuracy, for both trainees (from 64% to 74%) and FTs (from 56% to 65%). After 200 videos, sensitivity and specificity of 80% and higher for intestinal metaplasia were observed in half the participants, and a specificity for dysplasia greater than 95%, along with a relevant likelihood ratio for a positive result of 7 to 28 and likelihood ratio for a negative result of 0.21 to 0.82, were achieved by all of the participants. No constant learning curve was observed for the identification of Helicobacter pylori gastritis and sensitivity to dysplasia. The trainees had better results in all of the parameters, except specificity for dysplasia, compared with the FTs. Globally, participants agreed that the program's structure was adequate, except on the feedback, which should have consisted of a more detailed explanation of each answer.

LIMITATIONS

No formal sample size estimate.

CONCLUSION

A Web-based learning program could be used to teach and disseminate classifications in the endoscopy field. In this study, an NBI classification for gastric mucosal features seems to be easily learned for the identification of gastric preneoplastic lesions.

Creation of genome-wide protein expression libraries using random activation of gene expression

Here we report the use of random activation of gene expression (RAGE) to create genome-wide protein expression libraries. RAGE libraries containing only 5 x 10(6) individual clones were found to express every gene tested, including genes that are normally silent in the parent cell line. Furthermore, endogenous genes were activated at similar frequencies and expressed at similar levels within RAGE libraries created from multiple human cell lines, demonstrating that RAGE libraries are inherently normalized. Pools of RAGE clones were used to isolate 19,547 human gene clusters, approximately 53% of which were novel when tested against public databases of expressed sequence tag (EST) and complementary DNA (cDNA). Isolation of individual clones confirmed that the activated endogenous genes can be expressed at high levels to produce biologically active proteins. The properties of RAGE libraries and RAGE expression clones are well suited for a number of biotechnological applications including gene discovery, protein characterization, drug development, and protein manufacturing.

Cytotoxicity and mutagenicity of frameshift-inducing agent ICR191 in mismatch repair-deficient colon cancer cells

BACKGROUND

Deficiency of DNA mismatch repair is a common feature of cancers exhibiting instability of microsatellite DNA sequences. Cancers with microsatellite instability are recognizable by their high rate of spontaneous frameshift mutations within microsatellite sequences, their resistance to killing by cytotoxic agents, and their localization to specific tissues, e.g., the proximal colon and stomach. We hypothesized that the mismatch repair deficiency of these cancers would make them vulnerable to environmental or chemical frameshift-inducing agents. This study was undertaken to test whether exogenous frameshift-inducing agents selectively induce mutations in mismatch repair-deficient cells of mutagen-exposed tissues like the colon and whether cytotoxic doses of these agents would preferentially kill those cells.

METHODS

Cytotoxicity of the acridine mutagen 6-chloro-9-[3-(2-chloroethylamino)propylamino]-2-methoxy-acridine (ICR191), a DNA frameshift inducer, was determined in the mismatch repair-deficient human colon carcinoma cell line HCT116 versus the repair-reconstituted derivative HCT116+C3. Vulnerability to the mutagenic effects of ICR191 was determined by transfection of HCT116 or HCT116+C3 cells with a frameshift reporter vector, followed by treatment of the cells with ICR191. Alternatively, the reporter vector was reacted ex vivo with ICR191, and the derivatized vector was then transfected into HCT116 or HCT116+C3 cells.

RESULTS

ICR191 proved to be fivefold to 10-fold more potent in inducing mutations in mismatch repair-deficient HCT116 cells than in mismatch repair-proficient HCT116+C3 cells. Moreover, at cytotoxic doses of ICR191, repair-deficient HCT116 cells proved to be fivefold more vulnerable to killing than did HCT116+C3 cells.

CONCLUSIONS

Frameshift-inducing mutagens can selectively induce mutations in mismatch repair-deficient cells versus mismatch repair-proficient cells. Environmental exposures may, therefore, favor development of cancers with microsatellite instability in tissues like the gut. Frameshift-inducing agents can, however, also preferentially kill mismatch repair-deficient cancer cells and, thus, may be promising as model therapeutic compounds.