Does Magnifying Narrow-Band Imaging or Magnifying Chromoendoscopy Help Experienced Endoscopists Assess Invasion Depth of Large Sessile and Flat Polyps?

Background

Distinguishing deep submucosa (SM) from superficial SM cancer in large sessile and flat colorectal polyps (>2 cm) is crucial in making the most appropriate therapeutic decision. We evaluated the additional role of magnifying narrow-band imaging (NBI) and magnifying chromoendoscopy (MCE) in assessing the depth of invasion in large sessile and flat polyps in comparison to morphological evaluation performed by experienced endoscopists.

Methods

From May 2011 to December 2011, a total of 85 large sessile and flat polyps were analyzed. Endoscopic features of the polyps were independently evaluated by experienced endoscopists. Subsequently, the polyps were observed using magnifying NBI and MCE.

Results

A total of 58 intramucosal lesions and 27 SM cancers (five superficial and 22 deep) were identified. The diagnostic accuracy of the experienced endoscopists, NBI, and MCE were 92.9, 90.6, and 89.4 %, respectively, for deep SM cancer. In combination with NBI or MCE, the diagnostic accuracy of the experienced endoscopists did not change significantly for deep SM cancer, with an accuracy of 95.3 % for both NBI and MCE.

Conclusions

Conventional colonoscopy can differentiate superficial from deep SM cancers with an accuracy of as high as 92.9 % in large sessile and flat polyps. Further diagnostic strategies are required in order to precisely assess the depth of invasion, especially in large colorectal polyps.     

Low Prevalence of Microsatellite Instability in Interval Gastric Cancers

Background and Aim

Esophagogastroduodenoscopy (EGD) is recommended at 2-year intervals in countries with a high prevalence of gastric cancer. The aim of this study was to determine whether interval gastric cancers that develop within 2 years of a previous complete screening are associated with microsatellite instability (MSI).

Methods

Newly diagnosed gastric cancer patients who had undergone gastrectomy were included. Of these 459 patients, 177 were classified as interval gastric cancer since they were diagnosed within 2 years of a previous EGD. Noninterval gastric cancer patients were subclassified into 65 patients who underwent previous EGD between the past 2 and 10 years and 217 patients without EGD during the last 10 years. Analysis for MSI was conducted using two mononucleotide and three dinucleotide markers.

Results

MSI was found more frequently in noninterval gastric cancers than in interval gastric cancers (p = 0.009). Interval gastric cancers were associated with a higher prevalence of early gastric cancer (p = 0.006), smaller size (p < 0.001), and lower TNM stages (p = 0.006). On logistic regression analysis, noninterval gastric cancers were related to MSI (p = 0.010) and larger size (≥4 cm) (p = 0.009). Subjects with interval gastric cancer showed better survival than those with noninterval gastric cancer (p = 0.006).

Conclusions

During a 2-year screening interval, noninterval gastric cancers tend to be larger, more advanced, and associated with MSI. Biannual EGD screening is effective for detecting small gastric cancers at an early stage, but is not useful in detecting gastric cancers with MSI.     

Effect of Follow-Up Endoscopy on the Outcomes of Patients with Inflammatory Bowel Disease

Background

Little is known about the role of follow-up endoscopy in patients with inflammatory bowel disease (IBD).

Aim

The present study aimed to evaluate whether repeated endoscopies would be beneficial in improving outcomes of patients with IBD.

Methods

Patients who had been initially confirmed to have IBD at two tertiary hospitals in Korea were regularly followed and included in this study. The clinical impact as assessed by the presence or absence of a change in management after endoscopy and cumulative hospitalization rate was compared between two groups classified according to the presence or absence of indications.

Results

A total of 188 patients with IBD were enrolled [69 patients with Crohn’s disease (CD) and 119 with ulcerative colitis (UC)]. Of these patients, 130 underwent follow-up endoscopy (48 with CD and 82 with UC). The rate of management change was significantly higher in the group with indications for follow-up endoscopy (p = 0.001 in CD and <0.001 in UC). The presence of any indications for follow-up endoscopy was found to be a significant predictor of hospitalization risk in patients with UC (p = 0.015), but not in those with CD. However, there was no significant difference in cumulative hospitalization hazard with respect to treatment change in patients without any endoscopic indications (p = 0.561 in CD and 0.423 in UC).

Conclusions

Follow-up endoscopy might not have a significant impact on the overall clinical course and outcomes in patients with IBD. However, the presence of endoscopic indications predicts a poor clinical outcome in UC.     

Evaluation of pulmonary toxicity of benzalkonium chloride and triethylene glycol mixtures using in vitro and in vivo systems

Benzalkonium chloride (BAC) is a widely used disinfectant/preservative, and respiratory exposure to this compound has been reported to be highly toxic. Spray‐form household products have been known to contain BAC together with triethylene glycol (TEG) in their solutions. The purpose of this study was to estimate the toxicity of BAC and TEG mixtures to pulmonary organs using in vitro and in vivo experiments. Human alveolar epithelial (A549) cells incubated with BAC (1‐10 μg/mL) for 24 hours showed significant cytotoxicity, while TEG (up to 1000 μg/mL) did not affect cell viability. However, TEG in combination with BAC aggravated cell damage and inhibited colony formation as compared to BAC alone. TEG also exacerbated BAC‐promoted production of reactive oxygen species (ROS) and reduction of glutathione (GSH) level in A549 cells. However, pretreatment of the cells with N‐acetylcysteine (NAC) alleviated the cytotoxicity, indicating oxidative stress could be a mechanism of the toxicity. Quantification of intracellular BAC by LC/MS/MS showed that cellular distribution/absorption of BAC was enhanced in A549 cells when it was exposed together with TEG. Intratracheal instillation of BAC (400 μg/kg) in rats was toxic to the pulmonary tissues while that of TEG (up to 1000 μg/kg) did not show any harmful effect. A combination of nontoxic doses of BAC (200 μg/kg) and TEG (1000 μg/kg) promoted significant lung injury in rats, as shown by increased protein content and lactate dehydrogenase (LDH) activity in bronchoalveolar lavage fluids (BALF). Moreover, BAC/TEG mixture recruited inflammatory cells, polymorphonuclear leukocytes (PMNs), in terminal bronchioles and elevated cytokine levels, tumor necrosis factor α (TNF‐α), and interleukin 6 (IL‐6) in BALF. These results suggest that TEG can potentiate BAC‐induced pulmonary toxicity and inflammation, and thus respiratory exposure to the air mist from spray‐form products containing this chemical combination is potentially harmful to humans.     

Renal elasticity and perfusion changes associated with fibrosis on ultrasonography in a rabbit model of obstructive uropathy

To evaluate elasticity and perfusion change associated with fibrosis in a rabbit model of unilateral ureter obstruction using shear wave elastography (SWE) and contrast-enhanced ultrasonography (CEUS). Complete unilateral ureter obstruction by ligation was performed in the left kidney of 15 rabbits. Renal elasticity on SWE and perfusion change on CEUS at the renal cortex were measured before and after the operation. Histopathological renal fibrosis was quantified by the stained area ratio with Masson trichrome and Picrosirius red using ImageJ analysis. Renal elasticity and perfusion values were compared by the Mann-Whitney U test and Proc Mixed as a function of time. Spearman’s correlation was used to analyze differences between imaging values and fibrosis. The duration of imaging follow-up was up to 49 days, with interval imaging performed 1–3 times. Renal elasticity values were higher in obstructed kidneys compared to contralateral kidneys (31.0 kPa vs 16.4 kPa, p < 0.001) and increased according to postoperative time (0.46 kPa/day). With respect to renal fibrosis, SWE values were positively correlated with Masson trichrome (ρ = 0.651, p < 0.001) and Picrosirius red (ρ = 0.514, p = 0.007). Among CEUS parameters, mean transit time was negatively correlated with renal fibrosis by Masson trichrome (ρ = − 0.639, p = 0.001) and Picrosirius red (ρ = − 0.625, p = 0.001). Rise time and time to peak were positively correlated with renal fibrosis. Obstructive uropathy resulted in changes to both renal elasticity and perfusion. Renal fibrosis was moderately associated with increased renal cortical stiffness and both delayed and decreased cortical perfusion. • Obstructive uropathy causes changes in elasticity and perfusion in a rabbit model. • Renal fibrosis from obstructive uropathy increases renal cortical stiffness, and both delay and decrease cortical perfusion.