Where is the optimal plane to mobilize the anterior rectal wall in female patients undergoing total mesorectal excision?

BACKGROUND Since Heald proposed the total mesorectal excision(TME)procedure,the prognosis of patients with rectal cancer has been significantly improved.But Heald did not specifically describe the anterior surgical plane in female patients.And the surgical plane for mobilizing the anterior rectal wall during TME surgery in female patients remains controversial.AIM To investigate the anatomy of the female pelvis and identify the optimal plane for mobilizing the anterior rectal wall.METHODS We retrospectively collected surgical procedure videos and clinical data of female patients diagnosed with middle or low rectal cancer who underwent the TME procedure between January 2020 and October 2022 across six hospitals.The patients were divided into two groups based on the surgical approach used to mobilize the anterior rectal wall:The experimental group was to open the peritoneum at the lowest point of the peritonea reflection and enter the plane for mobilizing,while the control group was cut at 0.5-1 cm above the peritoneal reflection and enter another plan.Then,we compared the preoperative and postoperative information between the two groups.We also dissected and observed ten adult female pelvises to analyze the anatomic structure and compare the entry plane between the two approaches.Finally,we researched the pathological structure between the rectum and the vagina.RESULTS Finally,77 cases that met the criteria were included in our study.Our observations revealed that the experimental group underwent a smooth procedure,entering the plane amidst the mesorectal fascia and adventitia of the vagina,whereas the control group entered the plane between the vaginal adventitia and muscle layers.Compared to the control group,the experimental group showed a significant decrease in intraoperative bleeding[22.5(19.5-50)mL vs 17(5-20)mL,P=0.01],as well as a shorter duration of hospitalization[9(7-11.25)d vs 7(6-10)d,P=0.03].Through the examination of surgical videos and cadaveric studies,we discovered that Denonvilliers'fascia is absent in females.Additionally,pathological sections further revealed the absence of Denonvilliers'fascia in females,with only loose connective tissue present between the mesorectal fascia and adventitia of the vagina.CONCLUSION The plane amidst the mesorectal fascia and vaginal adventitia is the optimal surgical plane to mobilize the anterior rectal wall for female patients undergoing the TME procedure.

Radiofrequency ablation of hepatocellular carcinoma sized> 3 and ≤ 5 cm: Is ablative margin of more than 1 cm justified?

AIM:To investigate whether an ablative margin(AM)>1.0 cm might reduce chance of recurrence for patients with hepatocellular carcinoma(HCC)tumors 3.1to 5.0 cm in size,compared with an AM of 0.5-1.0 cm.METHODS:From October 2005 to December 2012,936 consecutive patients with HCC who received radiofrequency ablation were screened.Of these,281 patients,each with a single primary HCC tumor of 3.1 to5.0 cm in size on its greatest diameter,were included in the study.Based on the AM width,we categorized patients into the 0.5-1.0 cm group and the>1.0 cm group.Local tumor progression(LTP)-free survival,intrahepatic distant recurrence(IDR)-free survival and overall survival(OS)rates were obtained using the Kaplan-Meier method.RESULTS:The 1-,2-,3-,4-,and 5-year LTP-free survival rates and IDR-free survival rates were significantly higher in the>1.0 cm group compared with the 0.5-1.0cm group(97.5%,86.3%,73.6%,49.5%and 26.4%vs 91.3%,78.4%,49.5%,27.8%,and 12.8%;95.1%,90.3%,77.0%,61.0%and 48.3%vs 95.2%,85.9%,62.6%,47.2%and 28.5%;P<0.05).The 1-,2-,3-,4-,and 5-year OS rates were 98.6%,91.5%,69.2%,56.0%and 42.2%,respectively,in the 0.5-1.0 cm group and 100%,98.9%,90.1%,68.7%and 57.4%,respectively,in the>1.0 cm group(P=0.010).There were no significant differences in complication rates between the two groups.Both univariate and multivariate analyses identified AM as an independent prognostic factor linked to LTP,IDR,and OS.CONCLUSION:For HCC tumors>3.0 cm and≤5.0cm,AM>1.0 cm could reduce chances of recurrence compared with AM of 0.5-1.0 cm,emphasizing the need for a more defensive strategy using AMs>1.0 cm for ablating HCC tumors of 3.1 to 5.0 cm.

Anisodamine accelerates spontaneous passage of single symptomatic bile duct stones ≤ 10 mm

AIM:To investigate the rate of spontaneous passage of single and symptomatic common bile duct(CBD)stones≤10 mm in diameter in 4 wk with or without a2-wk course of anisodamine.METHODS:A multicenter,randomized,placebocontrolled trial was undertaken.A total of 197 patients who met the inclusion criteria were enrolled.Ninetyseven patients were assigned randomly to the control group and the other 100 to the anisodamine group.The anisodamine group received intravenous infusions of anisodamine(10 mg every 8 h)for 2 wk.The control group received the same volume of 0.9%isotonic saline for 2 wk.Patients underwent imaging studies and liver-function tests every week for 4 wk.The rate of spontaneous passage of CBD stones was analyzed.RESULTS:The rate of spontaneous passage of CBD stones was significantly higher in the anisodamine group than that in the control group(47.0%vs 22.7%).Most(87.2%,41/47)stone passages in the anisodamine group occurred in the first 2 wk,and passages in the control group occurred at a comparable rate each week.Factors significantly increasing the possibility of spontaneous passage by univariate logistic regression analyses were stone diameter(<5 mm vs≥5 mm and≤10 mm)and anisodamine therapy.Multivariate logistic regression analyses revealed that these two factors were significantly associated with spontaneous passage.CONCLUSION:Two weeks of anisodamine administration can safely accelerate spontaneous passage of single and symptomatic CBD stones≤10 mm in diameter,especially for stones<5 mm.

Nicotinamide overload may play a role in the development of type 2 diabetes

AIM： To investigate whether nicotinamide overload plays a role in type 2 diabetes. METHODS： Nicotinamide metabolic patterns of 14 diabetic and 14 non-diabetic subjects were compared using HPLC. Cumulative effects of nicotinamide and N^1-methylnicotinamide on glucose metabolism, plasma HzO2 levels and tissue nicotinamide adenine dinucleotide （NAD） contents of adult Sprague-Dawley rats were observed. The role of human sweat glands and rat skin in nicotinamide metabolism was investigated using sauna and burn injury, respectively. RESULTS： Diabetic subjects had significantly higher plasma N^1-methylnicotinamide levels 5 h after a 100-mg nicotinamide load than the non-diabetic subjects （0.89 ± 0.13 μmol/L vs 0.6 ± 0.13 μmol/L, P 〈 0.001）. Cumulative doses of nicotinamide （2 g/kg） significantly increased rat plasma Nl-methylnicotinamide concentrations associated with severe insulin resistance, which was mimicked by Nl-methy-Inicotinamide. Moreover, cumulative exposure to N^1- methylnicotinamide （2 g/kg） markedly reduced rat muscle and liver NAD contents and erythrocyte NAD/ NADH ratio, and increased plasma H2O2 levels. Decrease in NAD/NADH ratio and increase in H2O2 generation were also observed in human erythrocytes after exposure to N^1-methylnicotinamide in vitro. Sweating eliminated excessive nicotinamide （5.3-fold increase in sweat nicotinamide concentration 1 h after a 100-mg nicotinamide load）. Skin damage or aldehyde oxidase inhibition with tamoxifen or olanzapine, both being notorious for impairing glucose tolerance, delayed N^1- methylnicotinamide clearance. CONCLUSION： These findings suggest that nicotinamide overload, which induced an increase in plasma N^1- methylnicotinamide, associated with oxidative stress and insulin resistance, plays a role in type 2 diabetes.

Shape Optimization of Pressure Vessel Head Based on the Super-ellipse Equation

This paper studies optimal shape design of pressure vessel head subject to internal uniform pressure.The optimization aims at minimizing its maximum stress while the volume of the vessel head remains no less than the standard ellipsoidal head.Super-ellipse curve is selected to describe the middle surface shape of the vessel head because it represents a large family of curves with only two or three parameters and makes the design and manufacture easy.The performance of different elements and element sizes of FEM modeling is carefully studied in view of computational cost,accuracy and noises of von Mises stress.The response surface of the maximum stress vs.shape design parameters is approximated by a Kriging surrogate model with EI criterion for sampling adding,based on the parameter optimization which is carried out to search the optimal shape.Finally,it is shown by numerical comparison that the super-ellipsoidal head is better than the standard ellipsoidal head and the other vessel heads in the literature.

Temperature dependence in tensile properties and deformation behavior of GH4169 alloy

The effect of temperature on the tensile properties and deformation mechanism of GH4169 alloy has been systematically studied over a wide range of room temperature(RT)to 1000℃.The results indicate that the stress–strain curve of the alloy shows serrations at 200–600℃,and the character of the serrations changes from type A to type B and then to type C at different temperatures.The ultimate tensile strength of the alloy decreases gradually from RT to 600℃.The yield strength decreases slowly from RT to 700℃ but decreases rapidly above 800℃.Transmission electron microscopy analysis relieves that the primary deformation mechanism of the alloy below 500℃ is Orowan bypass mechanism.At temperatures between 600 and 700℃,the coordinated deformation of twins and cross-slip of dislocations are activated.The transformation of\upgamma^{\prime\prime}phase toδphase above 650℃ will decrease the strength.The primary deformation mechanism above 800℃ transforms into the repeated shearing of\upgamma^{\prime\prime}by dislocations to form multiple stacking faults.Recrystallized grains were observed above 800℃,and continuous dynamic recrystallization and discontinuous dynamic recrystallization were observed.The stress concentration caused by Nb-rich carbides is the cause of intracrystalline crack nucleation.At 700℃,grain boundary crack sprouting is caused by the combined effect of slip band impact on grain boundaries and grain boundary dislocation plugging.The relationship between the serrated flow behavior and the deformation mechanism has been discussed based on the experimental results.

Thermoelectric transport properties of Pb-Sn-Te-Se system

IV-VI compounds are considered as promising thermoelectric materials, and high thermoelectric performance was achieved in IV-VI solid solutions. In this work, the thermoelectric properties of Pb-Sn-Te-Se-based solid solutions were systematically investigated. Among these solid solutions, it is found that a figure of merit （ZT） peak value of 1.0 at 873 K can be obtained in （PbTe）0.5（SnTe）o.5, on account of the combination of superior electrical properties in SnTe and low thermal conductivity in PbTe. Furthermore, we investigated and summarized the thermoelectric transport properties and proposed the thermoelectric performance maps for the IV- VI solid solutions in Pb-Sn-Te-Se system. This comprehensive investigation on Pb-Sn-Te-Se-based solid solutions can effectively guide and scan thermoelectric performance for a given unknown composition and enhance the thermoelectric properties in IV-VI compounds.