Diagnostic utility of small-caliber and conventional endoscopes for gastric cancer and analysis of endoscopic false-negative gastric cancers

AIM: To analyze the diagnostic utility of a small-caliber endoscope(SC-E) and clinicopathological features of false-negative gastric cancers(FN-GCs). METHODS: A total of 21638 esophagogastroduodenoscopy(EGD) gastric cancer(GC) screening examinations were analyzed. Secondary endoscopic examinations(n = 3352) were excluded because most secondary examinations tended to be included in the conventional endoscopy(C-E) group. Detection rates of GCs and FN-GCs were compared between SC-E and C-E groups. FN-GC was defined as GC performed with EGD within the past 3 years without GC detection. Macroscopic types, histopathological characteristics and locations of FN-GCs were compared with firstly foundgastric cancers(FF-GCs) in detail. RESULTS: SC-E cases(n = 6657) and C-E cases(n = 11644), a total of 18301 cases, were analyzed. GCs were detected in 16(0.24%) SC-E cases and 40 C-E(0.34%) cases(P = 0.23) and there were 4 FN-GCs(0.06%) in SC-E and 13(0.11%) in C-E(P = 0.27), with no significant difference. FN-GCs/GCs ratio between SC-E and C-E groups was not significantly different(P = 0.75). The comparison of endoscopic macroscopic types of FN-GCs tended to be a less advanced type(P = 0.02). Histopathologically, 70.6% of FN-GCs were differentiated and 29.4% undifferentiated type. On the other hand, 43.0% of FF-GCs were differentiated and 53.8% undifferentiated type, so FN-GCs tended to be more differentiated type(P = 0.048). CONCLUSION: The diagnostic utility of SC-E for the detection of GCs and FN-GCs was not inferior to that of C-E. Careful observation for superficially depressed type lesions in the upper lesser curvature region is needed to decrease FN-GCs.

IN VIVO EFFECT OF HEPARIN PRETREATMENT OF SMALL-CALIBER DECELLULARIZED XENOGRAFT

Objective To develop a new vascular xenograft and to compare the in vivo behavior of thrombogenicity and intimal hyperplasia in the heparin-treated and the non-heparin-treated decellularized xenografts.Methods Canine common carotid arteries were decellularized by enzymatic and detergent extraction procedures.Then a part of decellularized vascular grafts were covalently linked with heparin.Xenografts with(n=24)and without(n=24)heparin treatment were implanted in rabbits' left and right carotid artery respectively as bypass grafts.Graft patency were checked by Duplex ultrasonography at 3 and 6 months after implantation.Twelve rabbits were euthanized randomly at 3 and 6 months respectively and bilateral grafts were explanted.Histological examination and immunohistochemical staining were performed to observe the vascular remodeling.The efficiency of heparin release was demonstrated with toluidine blue staining.HE staining and micrograph analysis system were used for valuating the intima hyperplasia(IH)of bilateral grafts.Results During implantation,thrombosis rate was 4% in the heparin-treated xenografts and 25% in the non-heparin-treated xenografts after 3 weeks(P<0.05).After 6 months,it was 8% versus 58% respectively(P<0.01).Both xenografts of two groups harvested at the end of 3 or 6 months showed a satisfactory cellular reconstruction of either smooth muscle cells or endothelial cells.Intimal hyperplasia in the heparin-treated vascular was less than in the non-heparin treated xenografts.In addition,intimal hyperplasia was liable to appear close to the proximal and distal anastomotic stoma.Toluidine blue staining demonstrated that heparin was slowly released during 6 months.Conclusion This study provides a new strategy to develop a small-caliber vascular xenograft through enzymatic-detergent extraction and heparin treatment.Heparin treatment of the decellularized xenograft is helpful for improving bypass graft patency and reducing intimal hyperplasia.If there was no thrombus,bilateral bypass grafts will undergo a vessel remodeling procedure.Canine common carotid artery treated by detergent and enzymatic extraction and heparin treatment may be used as a new small-caliber vascular xenograft.

Effect of swirling flow on platelet concentration distribution in small-caliber artificial grafts and end-to-end anastomoses

Platelet concentration near the blood vessel wall is one of the major factors in the adhesion of platelets to the wall.In our previous studies,it was found that swirling flows could suppress platelet adhesion in small-caliber artificial grafts and end-to-end anastomoses.In order to better understand the beneficial effect of the swirling flow,we numerically analyzed the near-wall concentration distribution of platelets in a straight tube and a sudden tubular expansion tube under both swirling flow and normal flow conditions.The numerical models were created based on our previous experimental studies.The simulation results revealed that when compared with the normal flow,the swirling flow could significantly reduce the near-wall concentration of platelets in both the straight tube and the expansion tube.The present numerical study therefore indicates that the reduction in platelet adhesion under swirling flow conditions in small-caliber arterial grafts,or in end-to-end anastomoses as observed in our previous experimental study,was possibly through a mechanism of platelet transport,in which the swirling flow reduced the near-wall concentration of platelets.

On the effect of pitch and yaw angles in oblique impacts of smallcaliber projectiles

A terminal ballistic analysis of the effects of 7.62 mm × 51 AP P80 rounds on inclined high-strength armor steel plates is the focus of the presented study.The findings of an instrumented ballistic testing combined with 3D advanced numerical simulations performed using the IMPETUS Afea? software yielded the conclusions.The experimental verification proved that slight differences in the pitch-andyaw angles of a projectile upon an impact caused different damage types to the projectile’s core.The residual velocities predicted numerically were close to the experimental values and the calculated core deviations were in satisfactory agreement with the experimental results.An extended matrix of the core deviation angles with combinations of pitch-and-yaw upon impact angles was subsequently built on the basis of the numerical study.The presented experimental and numerical investigation examined thoroughly the influence of the initial pitch and yaw angles on the after-perforation projectile’s performance.

An experiment evaluating how the tiny mass eccentricities in spinstabilized projectiles affect the position of impact points

This study investigates and quantifies some possible sources affecting the position of impact points of small caliber spin-stabilized projectiles(such as 12.7 mm bullets).A comparative experiment utilizing the control variable method was designed to figure out the influence of tiny eccentric centroids on the projectiles.The study critically analyzes data obtained from characteristic parameter measurements and precision trials.It also combines Sobol’s algorithm with an artificial intelligence algorithmdAdaptive Neuro-Fuzzy Inference Systems(ANFIS)ein order to conduct global sensitivity analysis and determine which parameters were most influential.The results indicate that the impact points of projectiles with an entry angle of 0°deflected to the left to that of projectiles with an entry angle of 90°.The difference of the mean coordinates of impact points was about 12.61 cm at a target range of 200 m.Variance analysis indicated that the entry angleei.e.the initial position of mass eccentricityehad a notable influence.After global sensitivity analysis,the significance of the effect of mass eccentricity was confirmed again and the most influential factors were determined to be the axial moment and transverse moment of inertia(Izz Iyy),the mass of a projectile(m),the distance between nose and center of mass along the symmetry axis for a projectile(Lm),and the eccentric distance of the centroid(Lr).The results imply that the control scheme by means of modifying mass center(moving mass or mass eccentricity)is promising for designing small-caliber spin-stabilized projectiles.