ObjectiveTo investigate the effect of electrospun chitosan/polylactic acid (ch/PLA) nerve conduit for repairing peripheral nerve defect in rats. MethodsNerve conducts loaded with ch/PLA was made by the way of electrospun. The mechanical property, hydrophility, biocompatibility were tested, and the scanning electron microscope was used to observe the ultrastructure. The same experiments were also performed on pure PLA nerve conducts as a comparison. Then, 54 Sprague Dawley rats were divided into 3 groups randomly, 18 rats in each group. Firstly, the 10 mm defects in the right sciatic nerves were made in the rats and were respectively repaired with ch/PLA (group A), autografts (group B), and no implant (group C). At 4, 8, and 12 weeks after operation, general observations, sciatic functional index (SFI), electrophysiological evaluation, wet weight of gastrocnemius and soleus muscles, histological examination, immunohistological analysis, and transmission electron microscopy were performed to evaluate the effects. ResultsCompared with pure PLA nerve conducts, the addition of chitosan could improve the mechanical property, hydrophility, biocompatibility, and ultrastructure of the nerve conducts. At 4 weeks postoperatively, the regenerated nerve bridged the nerve defect in group A. The SFI improved gradually in both group A and group B, showing no significant difference (P>0.05). Compound muscle action potentials and nerve conduction velocity could be detected in both group A and group B at 8 and 12 weeks after operation, and significant improvements were shown in both groups (P<0.05). The wet weight and myocyte cross section of gastrocnemius and soleus muscles showed no significant difference between group A and group B (P>0.05), but there was significant difference when compared with group C (P<0.05) at 12 weeks postoperatively. Immunohistological analysis revealed that S-100 positive Schwann cells migrated in both group A and group B, and axon also regenerated by immunohistological staining for growth associated protein 43 and neurofilaments 160. Transmission electron microscopy showed no significant difference in the diameter of nerve fiber between group A and group B (P>0.05), but the thickness of myelin sheath in group A was significantly larger than that in group B (P<0.05). ConclusionThe electrospun ch/PLA nerve conduits can effectively promote the peripheral nerve regeneration, and may promise an alternative to nerve autograft for repairing peripheral nerve defect.
Objective To evaluate the significance of lactate dehydrogenase (LDH) as a predictor of in-hospital mortality in patients with acute aortic dissection(AAD). Methods We conducted a retrospective analysis of the clinical data of 445 AAD patients who were admitted to the Second Xiangya Hospital of Central South University and the Changsha Central Hospital from January 2014 to December 2017 within a time interval of ≤14 days from the onset of symptoms to hospital admission, including 353 males and 92 females with the age of 45-61 years. LDH levels were measured on admission and the endpoint was the all-cause mortality during hospitalization. Results During hospitalization, 86 patients died and 359 patients survived. Increased level of LDH was found in non-survivors compared with that in the survived [269.50 (220.57, 362.58) U/L vs. 238.00 (191.25, 289.15) U/L, P<0.001]. A nonlinear relationship between LDH levels and in-hospital mortality was observed. Using multivariable logistic analysis, we found that LDH was an independent predictor of in-hospital mortality in the patients with AAD [OR=1.002, 95% CI (1.001 to 1.014), P=0.006]. Furthermore, using receiver operating characteristic (ROC) analysis, we observed that the best threshold of LDH level was 280.70 U/L, and the area under the curve was 0.624 (95% CI 0.556 to 0.689). Conclusion LDH level on admission is an independent predictor of in-hospital mortality in patients with AAD.
ObjectiveTo explore the independent factors related to clinical severe events in community acquired pneumonia patients and to find out a simple, effective and more accurate prediction method.MethodsConsecutive patients admitted to our hospital from August 2018 to July 2019 were enrolled in this retrospective study. The endpoint was the occurrence of severe events defined as a condition as follows intensive care unit admission, the need for mechanical ventilation or vasoactive drugs, or 30-day mortality during hospitalization. The patients were divided into severe event group and non-severe event group, and general clinical data were compared between two groups. Multivariate logistic regression analysis was performed to identify the independent predictors of adverse outcomes. Receiver operating characteristic (ROC) curve was constructed to calculate and compare the area under curve (AUC) of different prediction methods.ResultsA total of 410 patients were enrolled, 96 (23.4%) of whom experienced clinical severe events. Age (OR: 1.035, 95%CI: 1.012 - 1.059, P=0.003), high-density lipoprotein (OR: 0.266, 95%CI: 0.088 - 0.802, P=0.019) and lactate dehydrogenase (OR: 1.006, 95%CI: 1.004 - 1.059, P<0.001) levels on admission were independent factors associated with clinical severe events in CAP patients. The AUCs in the prediction of clinical severe events were 0.744 (95%CI: 0.699 - 0.785, P=0.028) and 0.814 (95%CI: 0.772 - 0.850, P=0.025) for CURB65 and PSI respectively. CURB65-LH, combining CURB65, HDL and LDH simultaneously, had the largest AUC of 0.843 (95%CI: 0.804 - 0.876, P=0.022) among these prediction methods and its sensitivity (69.8%) and specificity (81.5%) were higher than that of CURB65 (61.5% and 76.1%) respectively.ConclusionCURB65-LH is a simple, effective and more accurate prediction method of clinical severe events in CAP patients, which not only has higher sensitivity and specificity, but also significantly improves the predictive value when compared with CURB65.
ObjectiveTo explore the effect of silk fibroin/poly(L-lactic acid-co-e-caprolactone) [SF/P(LLA-CL)] nanofibrous scaffold on tendon-bone healing of rabbits.MethodsSF/P(LLA-CL) nanofibrous scaffold was fabricated by electrospinning methods. The morphology of the scaffold was observed by scanning electron microscope (SEM). Pre-osteoblasts MC3T3-E1 cells were seeded on the scaffold and cultured for 1, 3, and 5 days. Cell adhesion and proliferation were also observed by SEM. Meanwhile, twenty-four New Zealand white rabbits were randomly divided into the autogenous tendon group (control group) and the autogenous tendon wrapped with SF/P(LLA-CL) scaffold group (experimental group), with twelve rabbits in each group. An extra-articular model was established, the effect was evaluated by histological examination and mechanical testing.ResultsThe morphology of SF/P(LLA-CL) nanofibrous scaffold was random, with a diameter of (219.4±66.5) nm. SEM showed that the MC3T3-E1 cells seeded on the scaffold were in the normal shape, growing well, and proliferating with time course. The results of histological examination showed that inflammatory cells infltrated into the graft-host bone interface at 6 weeks after operation in both groups. Besides, the width of interface showed no significant difference between groups. At 12 weeks after operation, protruding new bone tissue could be observed at the interface in the experimental group, while scar tissue but no new bone tissue could be seen at the interface in the control group. Mechanical testing showed that there was no significant difference in the failure load and the stiffness between groups at 6 weeks after operation (P>0.05). The failure load and the stiffness in the experimental group were significantly higher than those in the control group at 12 weeks after operation (P<0.05).ConclusionThe SF/P(LLA-CL) nanofibrous scaffold has good cell biocompatibility and can effectively promote tendon-bone healing, thus providing new method for modifying graft for ACL reconstruction in the clinical practice.
Objective To study the influence of in vitro force-vascularization on in vivo vascularization of porous polylactic glycolic acid copolymer(PLGA) scaffolds with internal network channels (PPSINC). Methods After the in vitro forcevascula ization of PPSINCs covered with microvessel endothelial cells (MVEC) of mice, they were divided into two groups: the force-vascularization group (group A) and the control group with only PSINCs (group B). All the PPSINCs were planted in the mesentery of 12 mice for 2 and 4 weeks, the PPSINCs were cut out, the vascular ization of PPSINCs was investigated by histology and immunohistochemistry, and the vascularization area of the histologic section of the PPSINCswas measured with the computer-assistant image analysis system. Result After the in vitro forcevascularization of PPSINCs, the MVEC of the mice sticking on the channel wall could be seen. After the scaffold was im planted into the mice for 2 weeks, the vascularization area of the histologic section of PPSINCs (VA) in group A (2 260.91±242.35 μm2) was compared with that in group B (823.64±81.29 μm2)，and the difference was sig nificant in statistics（P＜0.01).The VA for 4 weeks in group A (17 284.36 ±72.67 μm2) was compared with that in group B (17 041.14±81.51 μm2), and the difference was not significant in statistics（P＞0.05）.The area of the actin positivestaining (AA) in the histologi c section of PPSINCs for 2 weeks’ implantation in group A (565.22±60.58 μm2) was compared with that in group B (205.91±16.25 μm2), and the difference was signi ficant in statistics（P＜0.01). After the implantation for 4 weeks, the VA in group A (4 321.09±19.82 μm2) was compared with group B (4 260.28±27.17 μm2), and the difference was not significant in statistics（P＞0.05）. Conclusion The PPSINC is a good simple scaffold model of vasculariazation. The in vitro force-vascularization can increase the in vivo vascularization of PPSINCs in the early stage.
Objective To investigate the correlation between the initial arterial blood lactic acid and Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ score in trauma patients and its value in prognosis. Methods From August 1st 2015 to July 31st 2016, the clinical data of trauma patients treated in Department of Emergency were analyzed retrospectively. All patients were divided into survival group and death group by observing 28-day prognosis. We compared the relationship between the initial blood lactate level and APACHEⅡ score, and analyzed the relationship between the above indexes and the prognosis of the patients. Results A total of 743 patients were enrolled, with692 in survival group and 51 in death group.The APACHEⅡ score and initial blood lactate level in the survival group [(9.93±4.62) points, (2.02±1.44) mmol/L] were significantly lower than those in the death group [(22.84±7.26) points, (4.60±3.69) mmol/L] with significant differences (t=18.20, 9.77; P<0.01). The APACHEⅡ score and the mortality rate of patients with lactic acid level >4 mmol/L were significantly higher than those of patients with lactic acid of 2-4 mmol/L and <2 mmol/L; the differences were significant (P<0.05). The blood lactate and mortality in patients with APACHEⅡ score >20 were significantly higher than those in the patients with ≤10 and 11-20; the differences were significant (P<0.05). There was a significant positive correlation between initial blood lactate level and APACHEⅡ score (r=0.426, P<0.01). Conclusions The initial blood lactate level and APACHEⅡ score of trauma patients are correlated with the severity of injury and mortality. Both of the increase of initial blood lactic acid level and APACHEⅡ score suggest the risk of death in trauma patients.
ObjectiveTo investigate the influences of lactic acid (LA), the final degradation product of polylactic acid (PLA) on the prol iferation and osteoblastic phenotype of osteoblast-l ike cells so as to provide theoretical basis for bone tissue engineering. MethodsRos17/2.8 osteoblast-l ike cells were harvested and divided into 3 groups. In groups A and B, the cells were cultured with the medium containing 4, 8, 16, 22, and 27 mmol/L L-LA and D, L-LA, respectively. In group C, the cells were cultured with normal medium (pH7.4). The cell prol iferation was determined with MTT method after 1, 3, and 5 days. The relative growth ratio (RGR) was calculated, and the cytotoxicity was evaluated according to national standard of China. In addition, the alkal ine phosphatase (ALP) activity of cells cultured with medium containing 4 mmol/L L-LA (group A), 4 mmol/ L D, L-LA (group B), and normal medium (group C) after 1 and 5 days were detected with ALP kits, and the relative ALP ratio (RAR) was calculated; after 21 days, the calcium nodules were tested with von Kossa staining method, and were quantitatively analyzed. ResultsWhen LA concentration was 4 mmol/L, the mean RGR of both groups A and B were all above 80%, and the cytotoxic grades were grade 0 or 1, which meant non-cytotoxicity. When LA concentration was 8 mmol/L and 16 mmol/ L, groups A and B showed cytotoxicity after 5 days and 3 days, respectively. When LA concentration was above 22 mmol/L, cell prol iferations of groups A and B were inhibited evidently after 1-day culture. At each LA concentration, RGR of group A was significantly higher than that of group B at the same culture time (P<0.05) except those at 4 mmol/L after 1-day and 3-day culture. After 1 day, the RAR of group A was significantly higher than that of group B on 1 day (144.1%±3.2% vs. 115.2%±9.8%, P<0.05) and on 5 days (129.6%±9.8% vs. 78.2%±6.9%, P<0.05). The results of von Kossa staining showed that the black gobbets in group A were obviously more than those of groups B and C. The staining area of group A (91.2%±8.2%) was significantly higher than that of groups B (50.3%±7.9%) and C (54.2%±8.6%) (P<0.05). ConclusionThe concentration and composition of LA have significant effects on the cell proliferation and osteoblastic phenotype of osteoblast-l ike cells.
Objective To explore the effect of NaOH on the surface morphology of three-dimensional (3D) printed poly-L-lactic acid (PLLA) mesh scaffolds. Methods The 3D printed PLLA mesh scaffolds were prepared by fused deposition molding technology, then the scaffold surfaces were etched with the NaOH solution. The concentrations of NaOH solution were 0.01, 0.1, 0.5, 1.0, and 3.0 mol/L, and the treatment time was 1, 3, 6, 9, and 12 hours, respectively. There were a total of 25 concentration and time combinations. After treatment, the microstructure, energy spectrum, roughness, hydrophilicity, compressive strength, as well as cell adhesion and proliferation of the scaffolds were observed. The untreated scaffolds were used as a normal control. Results 3D printed PLLA mesh scaffolds were successfully prepared by using fused deposition molding technology. After NaOH etching treatment, a rough or micro porous structure was constructed on the surface of the scaffold, and with the increase of NaOH concentration and treatment time, the size and density of the pores increased. The characterization of the scaffolds by energy dispersive spectroscopy showed that the crystal contains two elements, Na and O. The surface roughness of NaOH treated scaffolds significantly increased (P<0.05) and the contact angle significantly decreased (P<0.05) compared to untreated scaffolds. There was no significant difference in compressive strength between the untreated scaffolds and treated scaffolds under conditions of 0.1 mol/L/12 h and 1.0 mol/L/3 h (P>0.05), while the compression strength of the other treated scaffolds were significantly lower than that of the untreated scaffolds (P<0.05). After co-culturing the cells with the scaffold, NaOH treatment resulted in an increase in the number of cells on the surface of the scaffold and the spreading area of individual cells, and more synapses extending from adherent cells. Conclusion NaOH treatment is beneficial for increasing the surface hydrophilicity and cell adhesion of 3D printed PLLA mesh scaffolds.
ObjectiveTo assess the predictive abilities of postoperative regional oxygen saturation (rSO2) measured by near-infrared spectroscopy (NIRS) and lactate level for early postoperative outcome in children undergoing congenital heart disease surgery.MethodsA total of 73 children (43 males, 30 females, mean age of 91±18 days) undergoing cardiovascular surgery were enrolled from December 2016 to September 2017. The 73 children were divided into an early poor outcome group and a without poor outcome group. Binary logistic regression method was used to determine the independent factors of predicting early poor outcome. Receiver operating characteristic curve was used to identify the optimal cutoff values.ResultsThe early poor outcome rate was 47%. By regression analyses, nadir splanchnic rSO2 values, peak lactate level were 2 independent factors of predicting poor outcome. For nadir splanchnic rSO2 alone, the area under the ROC curve for poor outcome were 0.897. For peak lactate alone, the area under the ROC curve for poor outcome was 0.867. After combination of nadir splanchnic rSO2 and peak lactate, the area under the ROC curve for poor outcome increased to 0.944 (P<0.05).ConclusionCombining the parameter of nadir splanchnic rSO2 and peak lactate during the first postoperatively 24 hours yielded to a more accurate predictive ability for early outcome in children undergoing congenital cardiac surgery.