ABSTRACT
Objective:To evaluate the effect of sodium bicarbonate Ringer′s solution on acute kidney injury(AKI) following laparoscopic hepatectomy in elderly patients.Methods:A total of 362 American Society of Anesthesiologists Physical Status classification Ⅱ or Ⅲ elderly patients, aged 65-79 yr, with body mass index of 18-28 kg/m 2, scheduled for elective laparoscopic hepatectomy, were divided into 2 groups( n=181 each) using a random number table method: bicarbonate Ringer′s solution group(BR group) and lactated Ringer′s solution group(LR group). Bicarbonate Ringer′s solution and lactated Ringer′s solution were intravenously infused in BR group and LR group, respectively. All operations were performed under general anesthesia combined with abdominal fascia block, and the methods of controlled low central venous pressure and intermittent hepatic inflow occlusion were applied to reduce intraoperative bleeding. Radial artery blood samples were collected for blood gas analysis at 5 min before anesthesia induction(T 0), 20 min after occluding liver hilus(T 1), 10 min after hepatectomy and hemostasis(T 2), at the end of surgery(T 3) and at postanesthesia care unit discharge(T 4), and lactate value(Lac) was recorded. Blood samples from cubital vein were collected on admission to hospital(T A) and at 24(T 24) and 48 h after operation(T 48) for determination of serum creatinine(Cr) concentrations. Doppler-based renal resistive index(RRI) was measured at T A, T 4, T 24 and T 48. The incidence of AKI was calculated within 48 h after operation according to the Kidney Disease: Improving Global Outcomes criteria in 2012 for Cr concentration. Adverse reactions(such as nausea and vomiting) and complications(such as incision infection) within 48 h after operation were recorded. Results:Compared with the baseline at T 0, Lac concentrations were significantly increased at T 1-4 in both groups( P<0.01). Cr concentrations were significantly increased at T 24 and T 48, and RRI was increased at T 4, T 24 and T 48 than at T A in both groups( P<0.01). Compared with group LR, the incidence of AKI within 48 h after operation, Lac concentrations at T 3, 4, Cr concentrations at T 24 and T 48, and RRI at T 4, T 24 and T 48 were significantly decreased in group BR( P<0.05 or 0.01). There was no significant difference in the incidence of nausea, vomiting, incision infection, delirium, bile leakage and pulmonary infection within 48 h after operation among the two groups( P>0.05). Conclusions:Sodium bicarbonate Ringer′s solution can decrease the development of AKI following laparoscopic hepatectomy in elderly patients.
ABSTRACT
Objective:To evaluate the effect of selective cerebral mild hypothermia on small ubiquitin-like modifier 2/3 (SUMO2/3) modification of dynamin-related protein 1 (Drp1) in a rat model of cerebral ischemia-reperfusion (I/R).Methods:Sixty clean-grade healthy male Sprague-Dawley rats, aged 6-8 weeks, weighing 240-260 g, were divided into 4 groups ( n=15 each) using a random number table method: sham operation group (S group), cerebral I/R group (I/R group), selective cerebral mild hypothermia group (HT group) and normal temperature group (NT group). The operation was performed under the monitoring of cerebral temperature and rectal temperature.Only the cervical blood vessels were exposed in S group, while focal cerebral I/R was induced by 2 h middle cerebral artery occlusion (MCAO) followed by 24 h reperfusion in anesthetized animals in the other three groups.In HT group and NT group, 4 and 37 ℃ normal saline was perfused through the left internal carotid artery at a rate of 80 ml·kg -1·h -1 for 15 min, respectively. Modified neurological severity score (mNSS) was assessed at 24 h of reperfusion. Then the rats were sacrificed under deep anesthesia, brains were removed, brain tissues were obtained for determination of the percentage of cerebral infarct size (by TTC staining), and the ischemic penumbra tissues in the cerebral cortex were removed for examination of the ultra-structural changes of mitochondria (with a transmission electron microscope) and for determination of the SUMO2/3 modification of Drp1 (by CO-IP), expression of total Drp1 (T-Drp1) and total cytochrome c (T-Cytc) (by Western blot), and expression of mitochondrial outer membrane Drp1 (M-Drp1) and cytoplasmic Cytc (C-Cytc) (by Western blot) after isolation of mitochondria and cytoplasm. Results:Compared with S group, the mNSS and percentage of cerebral infarct size were significantly increased, the expression of M-Drp1, T-Drp1, C-Cytc and T-Cytc was up-regulated, and SUMO2/3 modification of Drp1 in ischemic penumbra area was increased ( P<0.05), the fragmentation of mitochondria was aggravated, and cristae rupture and vacuolation were obvious in the other three groups. Compared with I/R group, the mNSS and percentage of cerebral infarct size were significantly decreased, the expression of M-Drp1, T-Drp1, C-Cytc and T-Cytc was down-regulated, SUMO2/3 modification of Drp1 was increased ( P<0.05), the fragmentation of mitochondria was significantly attenuated, and cristae rupture and vacuolation were weakened in HT group. There were no significant differences in these detection parameters between NT group and I/R group ( P>0.05). Conclusions:The mechanism by which selective cerebral mild hypothermia alleviates the cerebral I/R injury is related to increased SUMO2/3 modification of Drp1, decreased binding of Drp1 to mitochondrial outer membrane, and reduced mitochondrial excessive fission in rats.
ABSTRACT
Objective:To investigate the effects of mild hypothermia on microglia polarization and janus kinase 2/signal transduction and transcriptional activation factor 3 (JAK2/STAT3) signaling pathway during cerebral ischemia-reperfusion (I/R) in rats.Methods:Forty-five clean-grade healthy male Sprague-Dawley rats, aged 8 weeks, weighing 260-280 g, were divided into 3 groups ( n=15 each) by the random number table method: sham operation group (S group), cerebral I/R group (I/R) and mild hypothermia group (H group). In I/R group and H group, cerebral I/R was induced by middle cerebral artery occlusion using a nylon thread in anesthetized animals, the nylon thread was removed to restore the perfusion after 2 h of occlusion, and the rectal temperature was maintained at 36-37 ℃ during the period. Group H was wiped with 75% alcohol for 3 h starting from the time point immediately after reperfusion, and the rectal temperature was maintained at 32-33℃. Modified neurological severity score (mNSS) was evaluated at 24 h of reperfusion. Animals were then sacrificed for determination of the cerebral infarct size (using TTC staining), expression of M1 marker inducible nitric oxide synthase (iNOS), M2 marker arginase 1(Arg-1), phosphorylated JAK2(p-JAK2)and phosphorylated STAT3(p-STAT3)(by Western blot), expression of iNOS mRNA and Arg-1 mRNA (by quantitative polymerase chain reaction), and contents of interleukin-6 (IL-6) and IL-10 (by enzyme-linked immunosorbent assay). Results:Compared with group S, mNSS and cerebral infarct size were significantly increased, the expression of iNOS, Arg-1 protein and mRNA in cerebral ischemic penumbral zone was up-regulated, and the p-JAK2/JAK2 ratio, p-STAT3/STAT3 ratio, and contents of IL-6 and IL-10 were increased in the other two groups ( P<0.05). Compared with I/R group, mNSS and cerebral infarct size were significantly decreased, the expression of iNOS protein and mRNA in cerebral ischemic penumbral zone was down-regulated, the expression of Arg-1 and mRNA was up-regulated, and the p-JAK2/JAK2 ratio, p-STAT3/STAT3 ratio and IL-6 content were decreased, and the IL-10 content was increased in group H ( P<0.05). Conclusions:Mild hypothermia can promote the polarization shift of microglia from M1 to M2 phenotype during cerebral I/R and inhibit the central inflammatory responses, and the mechanism may be related to inhibition of JAK2/STAT3 signaling pathway in rats.
ABSTRACT
Objective To propose a one-way fluid-structure interaction (FSI) method based on an idealized aortic dissection model, so as to analyze the hemodynamics and wall stress in the false lumen (FL) under the influence of multiple overlapping uncovered stents (MOUS). Methods Upon establishment of the numerical model, the models were divided into two categories according to whether the model involved FL perfused branch artery. The characteristics of hemodynamics and wall stress state in the post-operative scenarios were simulated under different surgical strategies. The wall stress state of the FL before and after thrombosis formation was also compared and analyzed. ResultsThe release process of the stents had little influence on wall stress of the FL. The high velocity and high wall shear stress (WSS) area in the FL could not be reduced by using the MOUS alone. If only the proximal entry tear was blocked with a covered stent-graft, the distal end would maintain a region of high flow rate and high WSS. The combination of covered stent-graft and MOUS would result in a region of low flow rate and low WSS, as well as reduced wall pressure and wall stress in the FL. Compared with the model with FL perfused branch arteries, the model without it was more likely to form a region of low flow rate and low WSS after surgery. However, blood pressure in the FL was relatively higher. The formation of thrombus in the FL could greatly reduce wall stress in the area covered by the thrombus. Conclusions The method proposed in this study can simultaneously investigate hemodynamics and wall stress characteristics of the FL, and provide support for studying mechanical mechanism of FL thrombolysis induced by MOUS and the post-operative aortic expansion.
ABSTRACT
Objective To simulate the interaction between the stent graft (SG) and the aortic wall with finite element (FE) analysis by considering the influence of residual stress field, so as to study the stent influence on stress distributions of the aortic wall. Methods The three-dimensional (3D) residual stress field was generated in an idealized bi-layered thick-wall aortic model via a stress-driven anisotropic growth model by reducing the transmural stress gradient. Upon virtually deploying the SG, the stress on the aortic wall was calculated. Results The 3D residual stress field, corresponding to an opening angle of 117.5°, was shown to reduce the transmural stress gradient in both the circumferential and axial directions. The maximum stress was found at the contact area between aortic wall and wave peak of the stent. At 20% oversize ratio of the stent, the maximum stresses on the aortic wall in circumferential and axial direction were 412 and 132 kPa, respectively, while the in-plane shear stresses σrθ and σrz were both 78 kPa. Under residual stress, the maximum radial, circumferential and axial stresses were decreased by 14.9%, 40.5% and 33.8%, respectively, while the maximum shear stresses σrθ ，σrz，σθz were reduced by 2.5%, 7.1% and 27%, respectively. With the increase of oversize ratio from 10% to 20%, the maximum radial, circumferential and axial stresses were increased by 316%, 129% and 41%, respectively, while the maximum shear stresses σrθ ，σrz，σθz were increased by 661%, 450% and 466%, respectively. Conclusions The residual stress can effectively reduce the transmural stress gradient. Both the residual stress and the oversize ratio of the stent play an important role in modulating the wall stress distribution and the maximum stress.
ABSTRACT
Objective The finite element method was used to analyze the effect of height of bone graft on adjacent segment stress after anterior cervical decompression and fusion.Methods One healthy adult male was included in this study.A detailed,geometrically accurate three-dimensional cervical spine model had been successfully developed from computed tomography (CT) scanning of a healthy adult male.A pure moment of 1.0 N· m was applied in different directions on the upper endplate of C3 to simulate flexion,extension,left-right lateral bending,and left-right axial rotation.We did biomechanical experiment with goat cervical specimens in terms of the moment-rotation responses.The finite element (FE) model was compared and validated with the experimental data.The relevant data in the literature was also applied for comparison and validation.To construct the post-surgery model,we turned the property of disk annulus and disk nucleus into that of the cancellous bone at C4-5.The internal fixation systems were also implanted.We changed the height of bone graft in C4-5 to be 90％,150％,175％ and 200％ of the height between C4-5 pre-surgery.The finite element models were built to simulate the post-surgery scenarios with different bone graft height,respectively.A stress analysis was conducted on the bone graft and adjacent disks.Results Under different height of bone graft,the maximum yon Mises stress on C3-4 showed when the height of bone graft was 200％.The values were 0.99 MPa,0.85 MPa,0.91 MPa and 0.89 MPa in different loading condition.The values at 150％ of the height between C4-5 pre-surgery were only 81％,73％,80％ and 87％ of the values at 200％.For C5-6,the maximum yon Mises stress were 0.77 MPa,0.83 MPa,0.91 MPa and 0.81 MPa,observed at the height of bone graft was 175％ except extension.The values at 150％ of the height between C4-5 pre-surgery were only 76％,93％,86％ and 78％ of the biggest values.With regard to C4-5,the biggest yon Mises stress was 1.25 MPa,1.77 MPa,1.75 MPa and 1.81 MPa.It was observed when the height of bone graft was 200％ of the height between C4-5 pre-surgery.The values were smallest under height of 150％ of the height between C4-5 pre-surgery.The smallest values were 63％,63％,75％ and 52％ of the biggest values.The higher the bone graft was,the bigger the maximum von Mises stress on bone graft.In a word,it seems that the smallest stress was observed when the bone graft height was 150％.Concltusion The height of bone graft makes an important difference on the stress of adjacent segment after anterior cervical decompression and fusion.150％ of the height between C4-5 presurgery was proper bone graft height.In this case,the stress on the adjacent segments intervertebral disc is smaller.The probability of adjacent segments degeneration is smaller.