A multiple-stimuli-responsive drug-conjugated cross-linked micelles was prepared by radical copolymerization. The chemical structure, morphology, and size of the cross-linked micelles were characterized, and the drug loading of the micelle was calculated. The experimental results indicated that the hydrodynamic size of the drug-loaded micelles were about 100 nm, and the as prepared micelles could be degraded and swelled in presence of reducing glutathione (GSH). The low critical solution temperature (LCST) of the micelle was around 39.4℃. According to the experimental results, the micelles will shrink at temperature above the LCST. Subsequently, the accumulative drug release rate was up to 91.78% under acidic (pH 5.0), reductive (GSH 10 mmol/L) and high temperature (42.0℃) conditions mimicking the tumor microenvironment, while a relatively low release rate of 1.12% was observed without stimulation. The drug-conjugated cross-linked micelles showed a strong cell uptake behavior. In the cytotoxicity assay, the micelles exhibited effective anti-cancer activity and excellent biocompatibility. In brief, the experimental results show that the as-prepared drug-conjugated cross-linked micelle exhibits multiple stimuli-responsiveness, which holds great promise for anti-cancer drug delivery.
The temperature dependence of relative permittivity and conductivity of ex-vivo pig liver, lung and heart at 2 450 MHz was studied. The relative permittivity and conductivity of three kinds of biological tissues were measured by the open-end coaxial line method. The dielectric model was fitted according to the principle of least square method. The results showed that the relative permittivity and conductivity of pig liver, pig lung and pig heart decreased with the increase of tissue temperature from 20 to 80 ℃. The relative permittivity and conductivity models of pig liver, pig lung and pig heart were established to reflect the law of dielectric properties of biological tissue changing with temperature and provide a reference for the parameters setting of thermal ablation temperature field.
Objective To investigate the clinical efficacy and safety of coblation-assisted adenotonsillectomy for treatment of children with obstructive sleep apnea hypopnea syndrome (OSAHS). Methods From June 2007 to May 2008, after monitoring polysomnography (PSG) confirmed 82 cases of OSAHS in children aged 3 to 14 years, with an average age of 6.2 years old, the ENT CoblatorII surgical instrument made by Arthrocare in the US and one-time EVac 70 T amp; A segment was used under complete anesthesia to remove tonsils and(or)adenoid ablation. Polysomnography monitoring was used preoperatively and 6 months postoperatively to determine the therapeutic effect. Results No significant complications occurred among the children both during the operation and postoperatively. Patients were followed for 6 months, and a satisfactory effect was achieved. The lowest oxygen saturation (LSaO2) improved significantly (Plt;0.001); the apnea-hypopnea index (AHI) decreased significantly after the operation (Plt;0.001). In accordance with OSAHS diagnosis and efficacy evaluation standards, 45 patients were cured after 6 months, 21 patients showed an excellent effect, 10 patients showed a good effect, six patients had no effect, and the total effective rate was 92.6%. Conclusion Low-temperature coblation-assisted adenotonsillectomy has good clinical efficacy with a shortened surgical time, less intraoperative and postoperative blood loss, less postoperative pain, few complications, and a simple operation procedure. It can effectively expand the nasopharynx, oropharynx ventilation cross-sectional area, lift the upper airway obstruction, and can be especially suitable for surgical treatment of children with OSAHS.
ObjectiveTo manufacture a polycaprolactone (PCL)/type Ⅰ collagen (COL Ⅰ) tissue engineered meniscus scaffold (hereinafter referred to as PCL/COL Ⅰ meniscus scaffold) by three-dimensional (3D) printing with low temperature deposition technique and to study its physicochemical properties.MethodsFirst, the 15% PCL/4% COLⅠ composite solution and 15% PCL simple solution were prepared. Then, 15% PCL/4% COL Ⅰmeniscus scaffold and 15% PCL meniscal scaffold were prepared by using 3D printing with low temperature deposition techniques. The morphology and microstructure of the scaffolds were observed by gross observation and scanning electron microscope. The compression modulus and tensile modulus of the scaffolds were measured by biomechanical test. The components of the scaffolds were analyzed by Fourier transform infrared spectroscopy (FTIR). The contact angle of the scaffold surface was measured. The meniscus cells of rabbits were cultured with the two scaffold extracts and scaffolds, respectively. After cultured, the cell proliferations were detected by cell counting kit 8 (CCK-8), and the normal cultured cells were used as controls. Cell adhesion and growth of scaffold-cell complex were observed by scanning electron microscope.ResultsAccording to the gross and scanning electron microscope observations, two scaffolds had orientated 3D microstructures and pores, but the surface of the PCL/COLⅠ meniscus scaffold was rougher than the PCL meniscus scaffold. Biomechanical analysis showed that the tensile modulus and compression modulus of the PCL/COL Ⅰ meniscus scaffold were not significantly different from those of the PCL meniscus scaffold (P>0.05). FTIR analysis results showed that COL Ⅰ and PCL were successful mixed in PCL/ COL Ⅰ meniscus scaffolds. The contact angle of PCL/COLⅠ meniscus scaffold [(83.19±7.49)°] was significantly lower than that of PCL meniscus scaffold [(111.13±5.70)°] (t=6.638, P=0.000). The results of the CCK-8 assay indicated that with time, the number of cells cultured in two scaffold extracts showed an increasing trend, and there was no significant difference when compared with the control group (P>0.05). Scanning electron microscope observation showed that the cells attached on the PCL/ COL Ⅰ meniscus scaffold more than that on the PCL scaffold.ConclusionPCL/COLⅠmeniscus scaffolds are prepared by 3D printing with low temperature deposition technique, which has excellent physicochemical properties without cytotoxicity. PCL/COLⅠmeniscus scaffold is expected to be used as the material for meniscus tissue engineering.
Objective To conduct a systematic review on the Electrocardiogram (ECG) changes in the workers exposed to high temperatures by means of meta-analysis.Methods The retrospective cohort studies on the relationship between high temperature and ECG abnormalities published from 1990 to May 2009 were searched in CNKI, VIP, WanFang database and CBM database. The literatures meeting the inclusive criteria were selected, the quality was assessed, the data were extracted, and the meta-analyses were conducted with RevMan 4.2.2 software. Results A total of 20 studies were included. The results of meta-analyses showed: the ECG abnormality rate of the high-temperature group was obviously superior to that of the control group with significant difference (OR=2.76, 95%CI 2.37 to 3.20, Plt;0.000 01). The high-temperature severely affected left ventricular hypertrophy (OR=3.49, 95%CI 2.83 to 4.31, Plt;0.000 01), sinus bradycardia (OR=2.83, 95%CI 2.33 to 3.43, Plt;0.000 01), and changes in ST-T segment (OR=2.63, 95%CI 1.48 to 4.68, P=0.000 10), which indicated that the abnormal changes of ECG, such as left ventricular hypertrophy, sinus tachycardia, sinus bradycardia, and changes in ST-T segment could be the sensitive indexes to monitor cardiovascular disease of workers exposed to high-temperature. Conclusion The incidence of ECG abnormalities caused by high-temperature operation is obviously superior to that of the control group, so it is required to strengthen the health monitoring and labor protection for the workers exposed to high temperature.
This paper aims to explore the thermal feelings of different cover materials effect on wheelchair cushion comfortableness, and to build a mathematical model for motorized wheelchair cushion comfortableness. By measuring temperature and humidity between the contact face of motorized wheelchair cushion and human body as well as the setting posture adjustment time while cushion cover materials are nylon cloth, leather, fishnets cloth. At the same time, each volunteer took a questionnaire about the comfort of different cushion cover materials. Results showed that fishnets cloth was most comfortable, leather was worst, while nylon cloth was in between the two. The experimental objective data were consistent with the subjective data. We built a back propagation (BP) neural network mathematical model for motorized wheelchair cushion comfortableness. This study will provide objective reference to motorized wheelchair for the designers and users.
ObjectiveTo systematically review the efficacy and safety of intravascular cooling versus surface cooling for induced mild hypothermia on the prognosis of patients with cardiac arrest (CA) after resuscitation.MethodsPubMed, EMbase, The Cochrane Library, CNKI and WanFang Data databases were electronically searched to collect cohort studies and randomized controlled trials (RCTs) about the efficacy and safety of intravascular cooling versus surface cooling for CA patients after resuscitation from inception to July 2019. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by using Stata 13.0 software.ResultsA total of 9 cohort studies and 3 RCTs involving 2 104 patients were included. The results of meta-analysis showed that: the rate of good neurological function was significantly higher (OR=1.45, 95%CI 1.18 to 1.78, P<0.001) and the induction time was significantly shorter (SMD=?1.35, 95%CI ?2.34 to ?0.36, P=0.008) in the intravascular cooling group, but there was no statistical difference in mortality between two groups (OR=0.84, 95%CI 0.70 to 1.00, P=0.053). In terms of complications related to mild hypothermia, the rate of excessive hypothermia (OR=0.27, 95%CI 0.18 to 0.41, P<0.001) and arrhythmia (OR=0.60, 95%CI 0.40 to 0.89, P=0.012) was significantly lower in the patients treated with intravascular cooling, but the incidence of coagulopathy was higher (OR=1.61, 95%CI 1.05 to 2.49, P=0.03). There was no statistical difference in the incidence of pneumonia between two groups (OR=1.20, 95%CI 0.94 to 1.53, P=0.147).ConclusionCurrent evidence shows that intravascular cooling has significant neurological protection for patients with CA compared with surface cooling since it can decrease the induction time and the rate of excessive hypothermia and arrhythmia, but it may have a negative effect on the coagulation function. Due to the limited quality and quantity of the included studies, more high-quality studies are needed to verify the above conclusion.
Objective
To systematically review the efficacy of maternal body temperature preservation during caesarean section.
Methods
Databases including PubMed, EMbase, The Cochrane Library (Issue 2, 2015), WanFang Data, CBM and CNKI were searched from inception to July 2015 to collect randomized controlled trials (RCTs) of body temperature preservation in patients with caesarean delivery. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was performed using RevMan5.3 software.
Results
A total of 15 RCTs involving 1 331 patients were included. The results of meta-analysis showed that patients in the temperature preservation group had a smaller body temperature variation (MD= –0.22, 95%CI –0.32 to –0.13, P < 0.000?01) and a lower incidence of shivering (RR=0.53, 95%CI 0.42 to 0.67, P < 0.000?01) than patients in the control group. There were no statistical differences between the two groups in blood loss (MD= –13.77, 95%CI –33.95 to 6.42, P=0.18) and newborn Apgar score (MD=0.12, 95%CI –0.37 to 0.6, P=0.64).
Conclusions
Current evidence shows that body temperature preservation measures can better protect patients with caesarean delivery. Specifically, body temperature preservation measures could reduce patients’ body temperature variation and incidence of shivering but had no effect on blood loss and newborn Apgar score. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify the above conclusion.
Patch clamp is a technique that can measure weak current in the level of picoampere (pA). It has been widely used for cellular electrophysiological recording in fundamental medical researches, such as membrane potential and ion channel currents recording, etc. In order to obtain accurate measurement results, both the resistance and capacitance of the pipette are required to be compensated. Capacitance compensations are composed of slow and fast capacitance compensation. The slow compensation is determined by the lipid bilayer of cell membrane, and its magnitude usually ranges from a few picofarads (pF) to a few microfarads (μF), depending on the cell size. The fast capacitance is formed by the distributed capacitance of the glass pipette, wires and solution, mostly ranging in a few picofarads. After the pipette sucks the cells in the solution, the positions of the glass pipette and wire have been determined, and only taking once compensation for slow and fast capacitance will meet the recording requirements. However, when the study needs to deal with the temperature characteristics, it is still necessary to make a recognition on the temperature characteristic of the capacitance. We found that the time constant of fast capacitance discharge changed with increasing temperature of bath solution when we studied the photothermal effect on cell membrane by patch clamp. Based on this phenomenon, we proposed an equivalent circuit to calculate the temperature-dependent parameters. Experimental results showed that the fast capacitance increased in a positive rate of 0.04 pF/℃, while the pipette resistance decreased. The fine data analysis demonstrated that the temperature rises of bath solution determined the kinetics of the fast capacitance mainly by changing the inner solution resistance of the glass pipette. This result will provide a good reference for the fine temperature characteristic study related to cellular electrophysiology based on patch clamp technique.
Objective To evaluate which is better method zymogen or low temperature frozen in removing vascular endothelial cell so as to lay a foundation for creating a kind of brace which is not to be rejected and the same as own blood vessel. Methods Fresh and not damaged umbilical blood vessel was collected from natural labour women, human umbilical blood vessel was remove carefully from normal foetus, then was put into disinfectant at 37℃ for 24 hours. They were divided into 3 groups:normal group(NG),zymogen group(ZG) and low temperature frozen group(LG). ZG: 0.1% collagenⅡ enzyme was addedin umbilical blood vessel and closed the both sides and the vascular endothelialcell was removed in 37℃ water. LG:Umbilical blood vessel was put into liquidnitrogen for 24 hours after frozened step by step, and then it was put into 37℃ water for 30-60 s and the vascular endothelial cells were washed away by normal saline. NG:Umbilical blood vessel was kept into 4℃ Kerb’s liquid. The bacteria were culturedin each group. The samples were stained by HE,elastic fiber and collagen fiberwere observed by light and scanning electron microscope. The difference of compliance was compared. Human leukocyte antigen ABC(HLA-ABC) and HLA-DR were observed by immunohistochemical method and the expression of antigen of umbilical blood vessel was analysed. Results In LG, umbilical vascular endothelial cells were removed completely; artery showed vertical smooth muscle and vein showed elastic membrane. InZG, umbilical vascular endothelial cells were removed completely after 20 minutes;artery showed vertical smooth muscle cells and vein showed lower endothelial layer. The vascular compliance in LG was higher than that in NG, and the latter was also higher than that in ZG,but showing no significant differences (Pgt;0.05). The compliance of umbilical vein was 2-3 times as much asthat of umbilical artery.The expression of HLA-ABC and HLA-DR in LG andZG were lower than that in NG, showing significant differences (Plt;0.01). Conclusion Low temperature frozen methodand zymogen method(0.1% collagen Ⅱ enzyme for 20 min) can remove vascular endothelial cells of human umbilical blood vessel completely.Low temperature frozenmethod was better than zymogen method.
