Circular RNAs (circRNAs) are a type of endogenous noncoding RNAs with covalently looped structures. Compared with other noncoding RNAs, circRNAs have the characteristics of stable structures, high abundance and tissue-specific expression. Recent studies have demonstrated that circRNAs can act as sponges, decoys and scaffolds for microRNAs and proteins, and play an important role in skin tumors. This review summarizes recent advances in the functions and mechanisms of action of circRNAs in common skin tumors, in order to understand the way in which they affect skin tumors, and to assess the value of further research on them.

Circular RNAs (circRNAs) are a type of endogenous noncoding RNAs with covalently looped structures. Compared with other noncoding RNAs, circRNAs have the characteristics of stable structures, high abundance and tissue-specific expression. Recent studies have demonstrated that circRNAs can act as sponges, decoys and scaffolds for microRNAs and proteins, and play an important role in skin tumors. This review summarizes recent advances in the functions and mechanisms of action of circRNAs in common skin tumors, in order to understand the way in which they affect skin tumors, and to assess the value of further research on them.

Objective:To investigate the clinical characteristics of choledocholithiasis com-bined with periampullary diverticulum and influencing factor for difficult cannulation of endoscopic retrograde cholangiopancreatography (ERCP).Methods:The retrospective case-control study was conducted. The clinical data of 1 920 patients who underwent ERCP for choledocholithiasis in 15 medical centers, including the First Hospital of Lanzhou University, et al, from July 2015 to December 2017 were collected. There were 915 males and 1 005 females, aged (63±16)years. Of 1 920 patients, there were 228 cases with periampullary diverticulum and 1 692 cases without periampullary diverticulum. Observation indicators: (1) clinical characteristics of patients with choledocholithiasis; (2) intraoperative and postoperative situations of patients undergoing ERCP for choledocholithiasis; (3) influencing factor analysis for difficult cannulation in patients undergoing ERCP for choledocholithiasis. Measurement data with normal distribution were represented as Mean±SD, and comparison between groups was conducted using the independent sample t test. Measurement data with skewed distribution were represented as M(range) or M( Q1, Q3), and com-parison between groups was conducted using the Wilcoxon rank sum test. Count data were described as absolute numbers or percentages, and comparison between groups was conducted using the chi-square test or Fisher exact probability. The Logistic regression model was used for univariate and multivariate analyses. Results:(1) Clinical characteristics of patients with choledocholithiasis. Age, body mass index, cases with complications as chronic obstructive pulmonary disease, diameter of common bile duct, cases with diameter of common bile duct as <8 mm, 8?12 mm, >12 mm, diameter of stone, cases with number of stones as single and multiple were (69±12)years, (23.3±3.0)kg/m 2, 16, (14±4)mm, 11, 95, 122, (12±4)mm, 89, 139 in patients with choledocholithiasis combined with periampullary diverticulum, versus (62±16)years, (23.8±2.8)kg/m 2, 67, (12±4)mm, 159, 892, 641, (10±4)mm, 817, 875 in patients with choledocholithiasis not combined with periampullary diver-ticulum, showing significant differences in the above indicators between the two groups ( t=?7.55, 2.45, χ2=4.54, t=?4.92, Z=4.66, t=?7.31, χ2=6.90, P<0.05). (2) Intraoperative and postoperative situations of patients undergoing ERCP for choledocholithiasis. The balloon expansion diameter, cases with intraoperative bleeding, cases with hemorrhage management of submucosal injection, hemostatic clip, spray hemostasis, electrocoagulation hemostasis and other treatment, cases with endoscopic plastic stent placement, cases with endoscopic nasal bile duct drainage, cases with mechanical lithotripsy, cases with stone complete clearing, cases with difficult cannulation, cases with delayed intubation, cases undergoing >5 times of cannulation attempts, cannulation time, X-ray exposure time, operation time were 10.0(range, 8.5?12.0)mm, 56, 6, 5, 43, 1, 1, 52, 177, 67, 201, 74, 38, 74, (7.4±3.1)minutes, (6±3)minutes, (46±19)minutes in patients with choledocholithiasis combined with periampullary diverticulum, versus 9.0(range, 8.0?11.0)mm, 243, 35, 14, 109, 73, 12, 230, 1 457, 167, 1 565, 395, 171, 395, (6.6±2.9)minutes, (6±5)minutes, (41±17)minutes in patients with choledocholithiasis not combined with periampullary diverticulum, showing significant differences in the above indicators between the two groups ( Z=6.31, χ2=15.90, 26.02, 13.61, 11.40, 71.51, 5.12, 9.04, 8.92, 9.04, t=?3.89, 2.67, ?3.61, P<0.05). (3) Influencing factor analysis for difficult cannulation in patients undergoing ERCP for choledocholithiasis. Results of multivariate analysis showed total bilirubin >30 umol/L, number of stones >1, combined with periampullary diverticulum were indepen-dent risk factors for difficult cannulation in patients with periampullary diverticulum who underwent ERCP for choledocholithiasis ( odds ratio=1.31, 1.48, 1.44, 95% confidence interval as 1.06?1.61, 1.20?1.84, 1.06?1.95, P<0.05). Results of further analysis showed that, of 1 920 patients undergoing ERCP for choledocholithiasis, the incidence of postoperative pancreatitis was 17.271%(81/469) and 8.132%(118/1 451) in the 469 cases with difficult cannulation and 1 451 cases without difficult cannula-tion, respectively, showing a significant difference between them ( χ2=31.86, P<0.05). In the 1 692 patients with choledocholithiasis not combined with periampullary diverticulum, the incidence of postopera-tive pancreatitis was 17.722%(70/395) and 8.250%(107/1 297) in 395 cases with difficult cannula-tion and 1 297 cases without difficult cannulation, respectively, showing a significant difference between them ( χ2=29.00, P<0.05). In the 228 patients with choledocholithiasis combined with peri-ampullary diverticulum, the incidence of postoperative pancreatitis was 14.865%(11/74) and 7.143%(11/154) in 74 cases with difficult cannulation and 154 cases without difficult cannulation, respectively, showing no significant difference between them ( χ2=3.42, P>0.05). Conclusions:Compared with patients with choledocholithiasis not combined with periampullary divertioulum, periampullary divertioulum often occurs in choledocholithiasis patients of elderly and low body mass index. The proportion of chronic obstructive pulmonary disease is high in choledocholithiasis patients with periampullary diverticulum, and the diameter of stone is large, the number of stone is more in these patients. Combined with periampullary diverticulum will increase the difficult of cannulation and the ratio of patient with mechanical lithotripsy, and reduce the ratio of patient with stone complete clearing without increasing postoperative complications of choledocholithiasis patients undergoing ERCP. Total bilirubin >30 μmol/L, number of stones >1, combined with periampullary diverticulum are independent risk factors for difficult cannulation in patients of periampullary diverticulum who underwent ERCP for choledocholithiasis.

Objective:To explore the application value of flexible endoscopy and rigid endoscopy in the clinical examination of chronic sinus tract wounds with different shapes.Methods:A retrospective observational study was conducted. From January 1 to December 23, 2019, a total of 46 patients with chronic sinus tract wounds, who met the inclusion criteria were admitted to the Wound Healing Center of Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, including 23 males and 23 females, aged 18-81 (48±21) years. On admission, computer tomography (CT) imaging and three-dimensional reconstruction were performed to examine the shapes of wound sinus tract and classify the wounds, with the lengths of wound sinus tract by CT imaging examination (hereinafter referred to as reference lengths) recorded. The lengths of wound sinus tract were examined and measured by rigid endoscopy and flexible endoscopy. The wounds with and without obviously curved sinus tract were classified into curve group and linear group respectively, and the deviation rates between the lengths of wound sinus tract measured by flexible endoscopy or rigid endoscopy and the reference lengths (hereinafter referred to as deviation rates of lengths) in each group were calculated. The difference between the deviation rates of lengths examined by flexible endoscopy and rigid endoscopy and the differences between the above two and the deviation rate of reference lengths (0) in each group were compared. Data were statistically analyzed with paired sample t test and Wilcoxon signed rank sum test. Results:CT imaging and three-dimensional reconstruction showed that there were 4 types of wound sinus tract, including tubular (36/46), lamellar (4/46), club-mallet (4/46), and irregular (2/46) shape. Tubular wounds were further divided into type I (23/36), type L (4/36), and type Y (9/36). Wounds with type I tubular, lamellar, and club-mallet sinus tract were classified into linear group (31/46), while those with type Y tubular, type L tubular, and irregular sinus tract were classified into curve group (15/46). In linear group, the deviation rates of lengths examined and measured by rigid endoscopy and flexible endoscopy were 0. In curve group, the deviation rate of lengths examined and measured by flexible endoscopy was 0 (0, 0.58%), which was significantly lower than 41.18% (31.68%, 48.41%) examined and measured by rigid endoscopy, Z=-3.408, P<0.01; the deviation rate of lengths examined and measured by rigid endoscopy (40±19)% was significantly higher than the deviation rate of reference lengths ( t=8.343, P<0.01), while the deviation rate of the lengths examined and measured by flexible endoscopy was similar to the deviation rate of reference lengths ( Z=-1.342, P>0.05). Conclusions:Compared with rigid endoscopy, flexible endoscopy can observe the internal characteristics of chronic sinus tract wounds in a wider range in the clinical examination of this kind of wound, especially for the exploration of curved chronic sinus tract wounds. The promotion of this method will be conducive to the diagnosis and treatment of chronic sinus tract wounds.

Objective: To explore the advantages of endoscopy combined with contrast fistulography in the clinical diagnosis and treatment of chronic wound with sinus tract adjacent to body cavity. Methods: Thirty-two patients (14 males and 18 females, aged 17 to 87 years) of chronic wounds with sinus tracts adjacent to body cavity, who underwent endoscopy combined with contrast fistulography (CT or magnetic resonance imaging) for the diagnosis and treatment in the Outpatient Department of Wound Healing Center of our hospital from October 2017 to March 2019, were enrolled in the study. Their diagnosis and treatment results were retrospectively analyzed. The following data were calculated. (1) The incidence rates of sinus wound involving body cavity or fistula. (2) The detection rates of sinus wound involving body cavity detected by routine examination and by endoscopy combined with contrast fistulography. (3) The detection rate of pathological features at deep part of wound by routine examination and by endoscopy combined with contrast fistulography. (4) The proportion of patients who benefited from routine examination and from endoscopy combined with contrast fistulography. Data were processed with paired chi-square test and Fisher′s exact probability test. Results: (1) The incidence rate of sinus wound involving body cavity was 43.75% (14/32); the incidence rate of fistula was 0. (2) The detection rate of sinus wound involving body cavity detected by endoscopy combined with contrast fistulography was 43.75% (14/32), which was obviously higher than that by routine examination [12.50% (4/32), χ²=32.0, P<0.01]. (3) The detection rate of pathological features at deep part of wound by endoscopy combined with contrast fistulography was 37.50% (12/32), which was obviously higher than that by routine examination (0, P<0.01). (4) The proportion of patients who benefited from endoscopy combined with contrast fistulography was 71.43% (20/28), which was obviously higher than that from routine examination [12.50% (4/32), χ²=21.6, P<0.01]. Conclusions Compared with routine examination, endoscopy combined with contrast fistulography is more accurate in detecting chronic wound with sinus tract adjacent to body cavity. The diagnosis and treatment of chronic wound with sinus tract adjacent to the body cavity can benefit from this joint examination.