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Bone defects have always been an important cause of threat to human health, and artificial biomimetic bone repair replacement materials are currently one of the most effective and feasible solution approaches to treat bone damage. To develop artificial bone biomimetic materials, an in vitro biomimetic mineralization system must be constructed first to study in vitro biomimetic mineralization mechanism of natural bone matrix. Collagen is a template for mineralization, and its properties such as crosslinking degree, diameter, osmotic pressure, and surface charge can all directly affect mineralization progress. The biochemical and mechanical environments in which mineralization occurs are also quite distinct in their effects on mineralization process, particularly noncollagenous proteins and fluid shear stress (FSS). FSS is considered to be the main mechanical stimulation of bone tissues in micro-environment, which is of great significance to bone growth, repair and health maintenance. FSS at different levels and loading regimes has significant effects on transformation of amorphous calcium phosphate to bone apatite, self-assembly and directional alignment of collagen fibrils, and formation of hierarchical intrafibrillar mineralization. In this paper, the factors affecting collagen mineralization and their mechanism were summarized, with focus on regulation of FSS on collagen mineralization, and development direction in future was also prospected.
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This article aims to study the factors affecting the flexibility of the tip of an epidural anesthesia catheter. The flexibility of the tip of the epidural anesthesia catheter was tested with a softness tester from four aspects:raw materials, tip structure, tip processing technology, and the outer diameter of the catheter. Highly flexible and malleable polymer material with a smooth tip, the tip softening process and the proper outer diameter can effectively improve the tip flexibility of the epidural anesthesia catheter.
Subject(s)
Anesthesia, Epidural , Catheterization , Catheters , Epidural SpaceABSTRACT
Pancreaticoduodenectomy is the main treatment method for pancreatic head carcinoma and periampullary cancer,and is also the only possible cure way.With the development of minimally invasive surgery,laparoscopic pancreaticoduodenectomy has been widely carried out,it even has been the routine operation in some pancreatic surgery center.The traditional approach is still the main approach for laparoscopic pancreaticoduodenectomy.In recent years,the procedure of the artery approach with its advantages has been put forward and gradually developed in laparoscopic pancreaticoduodenectomy through the continuous study and exploration.On the basis of the early arterial approach,authors' center established an artery preferential disconnection procedure in laparoscopic pancreaticoduodenectomy,which has been named arterial first approach.In the clinical practices and studies,this procedure also represents its unique advantages.
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Objective To investigate the clinical value of arterial first approach in laparoscopic pancreaticoduodenectomy (LPD).Methods The retrospective cohort study was conducted.The clinicopathological data of 181 patients with pancreatic head and periampullay tumors who underwent LPD in the Affiliated Tongji Hospital of Huazhong University of Science and Technology between October 2014 and December 2016 were collected.Among 181 patients,96 using arterial first approach and 85 using traditional approach were respectively allocated into the experimental group and the control group.Surgery was applied to patients in the same doctors' team,and there were the same extent of surgical resection,range of lymph node dissection and digestive tract reconstruction.Observation indicators:(1) intraoperative situation;(2) postoperative situation;(3) followup and survival situations.Follow-up using outpatient examination and telephone interview was performed to detect the tumor-free survival up to February 2017.Measurement data with normal distribution were represented as x±s,and comparison between groups was analyzed using the t test.Measurement data with skewed distribution were described as M (range).Comparison of count data were analyzed using the chi-square test or Fisher exact probability.Results (1) Intraoperative situation:all the patients underwent successful LPD.Overall operation time and time of digestive tract reconstruction were respectively (268 ± 20) minutes,(33 ± 10) minutes in the experimental group and (285±25)minutes,(30± 17)minutes in the control group,with no statistically significant difference between 2 groups (t =8.529,2.741,P＞ 0.05).Time of tumor resection with superior mesenteric venous invasion were respectively (216± 13)minutes and (264±22)minutes in the experimental and control groups,with a statistically significant difference between the 2 groups (t=41.826,P＜0.05).Time of tumor resection without superior mesenteric venous invasion were respectively (224± 14) minutes and (215±21) minutes in the experimental and control groups,with no statistically significant difference between the 2 groups (t =7.423,P＞ 0.05).Volumes of intraoperative blood loss and blood transfusion were respectively (99± 16)mL,(1.3±0.8)U in the experimental group and (131±27)mL,(2.8±1.2)U in the control group,with statistically significant differences between the 2 groups (t =3.670,0.562,P＜ 0.05).Five and 8 patients had intraoperative blood transfusion in the experimental and control groups,showing no statistically significant difference between the 2 groups (x2=1.195,P＞0.05).(2) Postoperative situation:time of drainage tube removal and duration of hospital stay were respectively (5.8±2.4)days,(18.3±6.3) days in the experimental group and (6.3±3.6)days,(19.6±7.1) days in the control group,with no statistically significant difference between the 2 groups (t =0.498,1.305,P＞0.05).Eleven patients in the experimental group had postoperative early complications,including 8with grade A pancreatic fistula (4 combined with diarrhea,2 combined with biliary fistula,1 combined with delayed gastric emptying and 1 with single pancreatic fistula),3 with grade B pancreatic fistula (2 combined with intra-abdominal hemorrhage and 1 combined with intra-abdominal infection).One patient with intra-abdominal hemorrhage in the experimental group died after treatment failure.Twelve patients in the control group had postoperative early complications,including 6 with grade A pancreatic fistula (2 combined with biliary fistula,2 combined with delayed gastric emptying,1 combined with diarrhea,1 combined with digestive tract hemorrhage),3 with grade B pancreatic fistula and intra-abdominal hemorrhage (2 combined with infection,including 1 death) and 3 with diarrhea.Other patients with complications were cured by symptomatic and supportive treatment.There was no statistically significant difference in overall complications between the 2 groups (x2 =0.287,P＞0.05).Results of postoperative pathological examination showed that case with R0 resection was 93 and 76 in the experimental and control groups,with a statistically significant difference between the 2 groups (x2 =4.057,P＜0.05).(3) Follow-up and survival situations:179 patients were followed up for 2-28 months,with a median time of 14 months.Postoperative 6-month tumor-free survival rate was 92.7％ (89/96) and 88.2％(75/85) in the experimental and control groups,with no statistically significant difference between the 2 groups (x2=1.060,P＞0.05).Conclusion Arterial first approach in LPD could significantly shorten the time of tumor resection of patients with superior mesenteric artery invading pancreatic head and periampullay region,significantly reduce the volumes of intraoperative blood loss and blood transfusion,and increase the rate of R0 resection.
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PURPOSE: Tubulointerstitial hypoxia in the kidney is considered a hallmark of injury and a mediator of the progression of tubulointerstitial fibrosis. Hypoxia-inducible factor-1alpha (HIF-1alpha), a master transcription factor in cellular adaptation to hypoxia, regulates a wide variety of genes, some of which are closely associated with tissue fibrosis. The present study set out to characterize urinary HIF-1alpha expressions in patients with lupus nephritis (LN) and to explore whether urinary HIF-1alpha expressions are associated with histologic chronicity changes and renal function. MATERIALS AND METHODS: Urinary HIF-1alpha levels were measured by enzyme-linked immunosorbent assays in 42 patients with LN and in 30 healthy controls. Activity and chronicity indexes as well as tubular HIF-1alpha expressions were analyzed for each specimen. RESULTS: Urinary HIF-1alpha levels were higher in LN patients than in healthy controls (3.977+/-1.696 vs. 2.153+/-0.554 ng/mL, p0.05). CONCLUSION: Urinary HIF-1alpha levels were elevated in LN patients and were associated with histologic chronicity changes and renal function, indicating that HIF-1alpha might contribute to histologic chronicity in LN.