Seungun Lee

Endoscopic ultrasound-guided versus conventional transmural drainage for pancreatic pseudocysts: a prospective randomized trial

BACKGROUND AND STUDY AIMS Although endoscopic ultrasound (EUS)-guided transmural drainage (EUD) is preferred over conventional transmural drainage (CTD) of pancreatic pseudocysts by endoscopy in many centers, its superiority with respect to technical success and clinical outcome has not yet been demonstrated in a prospective randomized trial. We conducted this prospective randomized trial to compare the technical success and clinical outcomes of EUD and CTD in treating pancreatic pseudocysts. PATIENTS AND METHODS A total of 60 consecutive patients with pancreatic pseudocysts were randomly divided into two groups to undergo either EUD (n = 31) or CTD (n = 29) of pancreatic pseudocysts. The technical success rate, complications, and short-term and long-term results were prospectively evaluated. RESULTS The rate of technical success of the drainage was higher for EUD (94 %, 29/31) than for CTD (72 %, 21/29; P = 0.039) in intention-to-treat analysis. In cases where CTD failed (n = 8), because the pseudocysts were nonbulging, a crossover was made to EUD, which was successfully performed in all these patients. Complications occurred in 7 % of the EUD and 10 % of the CTD group ( P = 0.67). During short-term follow-up, pseudocyst resolution was achieved in 97 % (28/29) in the EUD group and in 91 % (19/21) in the CTD group ( P = 0.565). Long-term results analyzed on a per-protocol basis showed no significant difference in clinical outcomes between EUD (89 %, 33/37) and CTD (86 %, 18/21, P = 0.696). CONCLUSIONS We found that EUD and CTD can both be considered first-line methods of endoscopic transmural drainage of bulging pseudocysts, whereas EUD should be preferred for nonbulging pseudocysts.

NK and NK-like T-cell lymphoma in extranasal sites: a comparative clinicopathological study according to site and EBV status.

Aims:  To analyse the clinicopathological findings of extranasal CD56+ cytotoxic T‐ or NK‐cell lymphomas in different organs and to compare Epstein–Barr virus (EBV)+ and EBV– lymphoma of non‐blastoid cytomorphology.

Outcomes of endoscopic transpapillary gallbladder stenting for symptomatic gallbladder diseases: a multicenter prospective follow-up study*

BACKGROUND AND STUDY AIMS Endoscopic transpapillary gallbladder drainage for symptomatic gallbladder disease is a safe and effective bridge therapy in patients at high risk for surgery or who have terminal liver disease and are awaiting transplantation. However, there are few reports on long-term results in terms of stent patency and clinical course. Our study was designed to investigate the long-term patency and clinical course after endoscopic transpapillary gallbladder stenting (ETGS) in patients with symptomatic gallbladder disease. PATIENTS AND METHODS A total of 29 patients who were unsuitable for cholecystectomy underwent ETGS from June 2006 to March 2010 using a 7-Fr double-pigtail stent between the gallbladder and the duodenum. Their clinical progress, adverse events, and stent patency after ETGS were recorded prospectively in two tertiary referral centers. RESULTS Technically, ETGS was successful in 23 (79.3%) of the 29 patients. The mean procedure time was 22.4 ± 11.5 min. Postprocedure adverse events were mild pancreatitis (8.7%) and cholestasis (8.7%), all of which resolved with conservative management. During the follow-up period (median 586 days, range 11-1403 days), 20 patients were analyzed as per protocol, and scheduled follow-up was performed. Late adverse events developed in four patients (20%), including distal migration (n = 2), cholangitis (n = 1), and recurrent biliary pain (n = 1). The remaining 16 patients were followed for more than 12 months (nine patients were followed for more than 24 months). Median stent patency was 760 days, as determined by the Kaplan-Meier method. CONCLUSIONS As a primary therapy, ETGS is technically feasible and effective in patients who are unsuitable for cholecystectomy. ETGS may also provide long-term stent patency without the need for scheduled stent exchanges.

Expression and prognostic implications of cell cycle regulatory molecules, p16, p21, p27, p14 and p53 in germinal centre and non‐germinal centre B‐like diffuse large B‐cell lymphomas

Aims : To evaluate the different expression patterns and the prognostic significance of cell cycle regulatory molecules in diffuse large B‐cell lymphomas (DLBCLs) of germinal centre (GC) and non‐GC phenotypes.

Primary and revision efficacy of cross-wired metallic stents for endoscopic bilateral stent-in-stent placement in malignant hilar biliary strictures

BACKGROUND AND STUDY AIMS Endoscopic bilateral drainage for inoperable malignant hilar biliary strictures (HBS) using metal stents is considered to be technically difficult. Furthermore, endoscopic revision of bilateral stenting after occlusion can be challenging. This study was performed to evaluate the long-term efficacy of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents in high-grade malignant HBS and planned endoscopic bilateral revision. PATIENTS AND METHODS A total of 84 patients with inoperable high-grade malignant HBS were enrolled from three academic tertiary referral centers. Two cross-wired metal stents were inserted using a bilateral stent-in-stent placement method. Bilateral endoscopic revision was also performed during follow-up using either identical metal stents or plastic stents. The main outcome measurements were technical and functional success, complications, stent patency, and endoscopic revision efficacy. RESULTS The technical and clinical success rates of endoscopic bilateral stent-in-stent placement of cross-wired metallic stents were 95.2% (80/84) and 92.9% (78/84), respectively. Median patency (range) and survival were 238 days (10-429) and 256 days (10-1130), respectively. Obstruction of primary bilateral stents occurred in 30.8% (24/78) of patients with functionally successful stent placement. The technical and clinical success rates of planned bilateral endoscopic revision for occluded stents were 83.3% (20/24) and 79.2% (19/24), respectively. For revision, bilateral metallic stents were placed in 11 patients (55.0%); the remaining patients received plastic stents. CONCLUSIONS Palliative endoscopic bilateral stent-in-stent placement of cross-wired metallic stents was effective in patients with inoperable HBS. Revision endoscopic bilateral stenting may be feasible and successful in cases where the primary deployed metal stents are occluded.

Mesenchymal stem cells protect against the tissue fibrosis of ketamine-induced cystitis in rat bladder

Abuse of the hallucinogenic drug ketamine promotes the development of lower urinary tract symptoms that resemble interstitial cystitis. The pathophysiology of ketamine-induced cystitis (KC) is largely unknown and effective therapies are lacking. Here, using a KC rat model, we show the therapeutic effects of human umbilical cord-blood (UCB)-derived mesenchymal stem cells (MSCs). Daily injection of ketamine to Sprague-Dawley rats for 2-weeks resulted in defective bladder function, indicated by irregular voiding frequency, increased maximum contraction pressure, and decreased intercontraction intervals and bladder capacity. KC bladders were characterized by severe mast-cell infiltration, tissue fibrosis, apoptosis, upregulation of transforming growth factor-β signaling related genes, and phosphorylation of Smad2 and Smad3 proteins. A single administration of MSCs (1 × 106) into bladder tissue not only significantly ameliorated the aforementioned bladder voiding parameters, but also reversed the characteristic histological and gene-expression alterations of KC bladder. Treatment with the antifibrotic compound N-acetylcysteine also alleviated the symptoms and pathological characteristics of KC bladder, indicating that the antifibrotic capacity of MSC therapy underlies its benefits. Thus, this study for the first-time shows that MSC therapy might help to cure KC by protecting against tissue fibrosis in a KC animal model and provides a foundation for clinical trials of MSC therapy.

Histopathological characteristics of interstitial cystitis/bladder pain syndrome without Hunner lesion

To assess the distinct histopathological characteristics and their clinical significance between non‐Hunner‐type and Hunner‐type interstitial cystitis (IC)/bladder pain syndrome (BPS).

Is the rate of post-ERCP pancreatitis not reduced by guide-wire cannulation?

We read with great interest the paper on the role of guide−wire cannulation with regard to post−ERCP pancreatitis (PEP) by Bailey et al. [1]. To date, the results for guide−wire cannulation in the prevention of PEP are conflicting [2 ± 4]; Bailey et al. carried out a neat prospective random− ized trial on this issue. In their study [1], interestingly, guide−wire cannulation im− proved the primary success rate for bili− ary cannulation during ERCP but did not reduce the incidence of PEP, compared with conventional contrast cannulation. However, regarding the results for guide− wire cannulation and PEP, we are con− cerned about a methodological issue. This study was a crossover trial: if the en− doscopist failed to cannulate with the randomized technique, then crossover to the other arm (guide−wire or contrast) oc− curred. Ultimately a substantial propor− tion of the enrolled patients (17.4%, 72 of 413) were crossed over. The crossover de− sign may be useful for the evaluation of successful cannulation rates using guide wire or contrast, as in the study of Katsi− nelos et al. [5] in the same issue of Endos− copy, but with regard to post−ERCP pan− creatitis, however, the crossover could mix the results for the two arms with re− gard to PEP. Theoretically, where the pa− tient has been crossed over, guide−wire cannulation following contrast injection could show a higher PEP rate because of the contrast injection part of the proce− dure, while contrast injection following guide−wire cannulation could show a lower PEP rate because of the guide wire cannulation. In addition, pancreatic stents were placed twice as frequently in the contrast arm compared with the guide−wire arm. Given these issues, therefore, it may be a premature conclu− sion that guide−wire cannulation can not reduce the rate of PEP. According to our own and other prospective randomized trials [2, 3, 6], a guide−wire cannulation performed by a single operator is asso− ciated with a low PEP rate. More refined methodology may be needed to clarify the role of guide−wire cannulation in the prevention of PEP.

Improved efficacy and in vivo cellular properties of human embryonic stem cell derivative in a preclinical model of bladder pain syndrome

Interstitial cystitis/bladder pain syndrome (IC/BPS) is an intractable disease characterized by severe pelvic pain and urinary frequency. Mesenchymal stem cell (MSC) therapy is a promising approach to treat incurable IC/BPS. Here, we show greater therapeutic efficacy of human embryonic stem cell (hESC)-derived multipotent stem cells (M-MSCs) than adult bone-marrow (BM)-derived counterparts for treating IC/BPS and also monitor long-term safety and in vivo properties of transplanted M-MSCs in living animals. Controlled hESC differentiation and isolation procedures resulted in pure M-MSCs displaying typical MSC behavior. In a hydrochloric-acid instillation-induced IC/BPS animal model, a single local injection of M-MSCs ameliorated bladder symptoms of IC/BPS with superior efficacy compared to BM-derived MSCs in ameliorating bladder voiding function and histological injuries including urothelium denudation, mast-cell infiltration, tissue fibrosis, apoptosis, and visceral hypersensitivity. Little adverse outcomes such as abnormal growth, tumorigenesis, or immune-mediated transplant rejection were observed over 12-months post-injection. Intravital confocal fluorescence imaging tracked the persistence of the transplanted cells over 6-months in living animals. The infused M-MSCs differentiated into multiple cell types and gradually integrated into vascular-like structures. The present study provides the first evidence for improved therapeutic efficacy, long-term safety, and in vivo distribution and cellular properties of hESC derivatives in preclinical models of IC/BPS.

Interobserver reproducibility of cervical lymph node measurements at CT in patients with head and neck squamous cell carcinoma

AIM To determine the interobserver reproducibility of measuring cervical lymph nodes at computed tomography (CT) in patients with head and neck squamous cell carcinoma (HNSCC) and to investigate the influence of finding extracapsular spread (ECS) at CT on measurement reliability. MATERIALS AND METHODS The institutional review board approved the study protocol, and informed consent was obtained. A total of 146 patients with 224 suspicious lymph nodes underwent CT before treatment. Two observers independently measured the diameters (minimal axial, maximum axial, and maximum longitudinal diameter) and assessed the ECS using CT. The greatest diameter was defined as the largest among the three measured diameters. Interobserver variability was determined by the within-subject coefficient of variation, and interobserver agreement was determined by the intraclass correlation coefficient (ICC). RESULTS The within-subject coefficients of variation were 7.8%, 7.6%, and 11.4% for the minimal axial, maximum axial, and greatest diameters, respectively. The ICC values for interobserver agreement were excellent for all diameter measurements (i.e., ICC >0.9). Minimum and maximum axial diameter measurements were statistically more reliable than the greatest diameter measurement (p=0.008 and p=0.0001, respectively). The presence of ECS on CT does not significantly affect the reliability of lymph node diameter measurements (p>0.05). CONCLUSION Lymph node diameter measurement on CT is a highly reproducible and robust method. Additionally, imaging features of ECS do not affect reliability. Therefore, the measurement of lymph node diameter can be confidently performed in daily clinical practice or clinical trials.