Improved rat liver decellularization by arterial perfusion under oscillating pressure conditions

One approach of regenerative medicine to generate functional hepatic tissue in vitro is decellularization and recellularization, and several protocols for the decellularization of livers of different species have been published. This appears to be the first report on rat liver decellularization by perfusion under oscillating pressure conditions, intending to optimize microperfusion and minimize damage to the ECM. Four decellularization protocols were compared: perfusion via the portal vein (PV) or the hepatic artery (HA), with (+P) or without (–P) oscillating pressure conditions. All rat livers (n = 24) were perfused with 1% Triton X‐100 and 1% sodium dodecyl sulphate, each for 90 min with a perfusion rate of 5 ml/min. Perfusion decellularization was observed macroscopically and the decellularized liver matrices were analysed by histology and biochemical analyses (e.g. levels of DNA, glycosaminoglycans and hepatocyte growth factor). Livers decellularized via the hepatic artery and under oscillating pressure showed a more homogeneous decellularization and less remaining DNA, compared with the livers of the other experimental groups. The novel decellularization method described is effective, quick (3 h) and gentle to the extracellular matrix and thus represents an improvement of existing methodology. Copyright © 2014 John Wiley & Sons, Ltd.     

Accurate measurement of intraarterial pressure through radial artery catheters in neonates

A technique is described for accurate measurement of intraarterial pressure through radial artery catheters in neonates. The technique, which can be used for short-term monitoring, uses cannulation of the radial artery with a 24-gauge Teflon catheter, connected by a Luer-Lok fitting to a threeway stopcock and a high-fidelity tip transducer. In vitro studies showed that the system is linear and the frequency response is flat (±3 dB) up to 50 Hz. The technique permits gathering of high-quality pressure data and can be used in the area of neonatal clinical research for short-term monitoring. It needs to be developed further before routine application in clinical practice can be recommended.     

A dynamic distention protocol for whole‐organ bladder decellularization: histological and biomechanical characterization of the acellular matrix

A combined physical–chemical protocol for whole full‐thickness bladder decellularization is proposed, based on organ cyclic distention through repeated infusion/withdrawal of the decellularization agents through the urethra. The dynamic decellularization was intended to enhance cell removal efficiency, facilitating the delivery of detergents within the inner layers of the tissue and the removal of cell debris. The use of mild chemical detergents (hypotonic solution and non‐ionic detergent) was employed to limit adverse effects upon matrix 3D ultrastructure. Inspection of the presence of residual DNA and RNA was carried out on decellularized matrices to verify effective cell removal. Histological investigation was focused on assessing the retention of adequate structural and functional components that regulate the biomechanical behaviour of the acellular tissue. Biomechanical properties were evaluated through uniaxial tensile loading tests of tissue strips and through ex vivo filling cystometry to evaluate the whole‐organ mechanical response to a physiological‐like loading state. According to our results, a dynamic decellularization protocol of 17 h duration with a 5 ml/min detergent infusion flow rate revealed higher DNA removal efficiency than standard static decellularization, resulting in residual DNA content < 50 ng/mg dry tissue weight. Furthermore, the collagen network and elastic fibres distribution were preserved in the acellular ECM, which exhibited suitable biomechanical properties in the perspective of its future use as an implant for bladder augmentation. Copyright © 2013 John Wiley & Sons, Ltd.     

Discrepancy of blood pressure between the brachial artery and radial artery

BACKGROUND:

In this study, we attempted to find the relations between blood pressure (BP) measured on the brachial artery (bBP) and BP assessed on the radial artery (rBP) in the right arm.

METHODS:

Three hundred and fifteen patients were enrolled in this study. Those who had peripheral vascular disease, wounds of arm skin or subcutaneous tissue infection were excluded. After a 15-minute equilibration and stabilization period after inducation of anesthesia, three bBP and rBP records were obtained sequentially using an oscillometric device with an adult cuff and infant cuff, respectively. Order for each BP was randomized.

RESULTS:

The bBP was significantly lower than the rBP (P<0.05). The difference between the two values varied from 13 to 18 mmHg in systolic BP (SBP), diastolic BP (DBP) and mean blood pressure (MAP) respectively. And the rBP was positively correlated with the bBP (r=0.872, 0.754, 0.765; P<0.001, <0.001, <0.001; SBP, DBP, MAP, respectively).

CONCLUSION:

The bBP value can be evaluated by the noninvasive measurements of rBP using an appropriate cuff in clinical practice.KEY WORDS: Blood pressure, Brachial artery, Radial artery, Correlation, Linear regression     

患者右侧桡动脉与肱动脉无创血压值的关系

目的 研究患者右侧桡动脉(B)与肱动脉无创血压值(R)的关系.方法 随机选择全麻下手术前的患者295例,年龄(47±16)岁,男:女比例为149∶146,身高(163 ±8) cm,体质量(61.2±7.8)kg.排除主动脉或外周血管疾病、右臂外伤或感染等情况者.待其生命体征平稳后分别采用成人袖带及儿童袖带测量其右上肢肱动脉与桡动脉血压无创血压值,并记录为收缩压(SBP)/舒张压(DBP)及平均压(MAP).用SPSS 16.0统计软件进行数据分析,肱、桡动脉血压相关性分析采用线性回归法,各区间的桡、肱动脉差值的比较采用单因素方差分析,各区间两两比较采用SNK-q法.结果 成人袖带所测右上臂肱动脉血压明显低于儿童袖带所测右前臂桡动脉血压,它们之间具有显著的线性相关性[r =0.841 (SBP)、0.808 (DBP)、0.833 (MAP),均P＜0.01].肱、桡SBP、DBP和MBP之间的差值为13～18 mm Hg(1 mmHg=0.133 kPa).结论 选择儿童袖带测量患者桡动脉血压可较好的反映肱动脉血压值的变化.     

利用周期性静水压在水力聚焦生物反应器中构建组织工程软骨

目的探讨在水力聚焦生物反应器(HFB)中加载周期性静水压构建组织工程软骨。方法分离培养兔关节软骨细胞并接种到PLGA支架上,细胞支架复合物分为加载周期性静水压的实验组和不加压的对照组,加压组的条件为:频率0.1Hz,压力0~200 kPa,每天加压8 h,两组均在HFB生物反应器中培养2周,利用免疫组织化学、RT-PCR、生物化学等方法观察周期性静水压对HFB生物反应器中构建的组织工程软骨的影响。结果免疫组织化学显示加压组的Ⅱ型胶原和甲苯胺蓝的染色面积明显大于对照组(P<0.001)。RT-PCR显示加压组的Ⅱ型胶原、聚合素的表达高于对照组(P<0.001),但Ⅰ型胶原的表达低于对照组(P<0.05)。生物化学定量检测显示加压组的总胶原和糖胺多糖(GAG)的含量显著高于对照组(P<0.001)。结论周期性静水压对HFB生物反应器中构建的组织工程软骨具有显著的促进促进作用,并且稳定了软骨细胞的表型。     

Optimizing the decellularization process of human maxillofacial muscles for facial reconstruction using a detergent‐only approach

Trauma, congenital diseases, and cancer resection cause muscle deformities of the human facial muscle. Muscle defects are either treated with local or distal flaps if direct closure is not possible. However, such surgical interventions are limited by donor morbidity and limited tissue availability. Decellularized scaffolds provide alternative strategies for replacing and restoring missing facial muscle by creating scaffolds that mimic the native tissue. This study aimed to develop a protocol to decellularize human zygomaticus major muscle (ZMM) and masseter muscle (MM). Three protocols were assessed including a detergent‐only treatment (DOT), detergent‐enzymatic treatment (DET) protocol, and a third nondetergent nonenzymatic treatment protocol. Scaffolds were then characterized via histological, immunofluorescent, and quantitative techniques to assess which protocol provided optimal decellularization and maintenance of the extracellular matrix (ECM). The results demonstrated three cycles of DOT protocol consisting of 2% sodium dodecyl sulfate for 4 hr was optimal for decellularization for both ZMM and MM. After three cycles, DNA content was significantly reduced compared with native ZMM and MM (p < .05) with preservation of collagen and glycosaminoglycan content and ECM on histological analysis. DET and nondetergent nonenzymatic treatment protocols were unsuccessful in decellularizing the ZMM and MM with residual DNA content after four cycles and caused ECM disruption on histological analysis. All protocols did not impair the mechanical properties and supported human fibroblast growth. In conclusion, the DOT protocol is effective in producing human decellularized muscle scaffolds that maintain the ECM. Further investigation of detergent only decellurization techniques should be explored as a first step to create effective scaffolds for muscle tissue engineering.     

经皮桡动脉与股动脉穿刺冠状动脉介入术后的护理观察

目的比较经桡动脉和股动脉穿刺冠状动脉介入术后的并发症发生情况,并分析相应的护理措施。方法选择220例经皮冠状动脉成形术患者分成对照组（经股动脉穿刺）和观察组（经桡动脉穿刺）各110例,比较2组患者治疗并发症的发生情况并总结相应护理措施。结果观察组患者住院时间和住院费用均显著优于对照组患者,差异具有统计学意义（P＜0.05）; 观察组患者局部小水肿、局部大水肿、迷走神经反射、假性动脉瘤、动静脉瘘、局部感染、肢体水肿以及不适反应等并发症的发生率均显著低于对照组患者（P＜0.05）。结论与经股动脉穿刺相比,经桡动脉穿刺的术后并发症发生率较低,且能在一定程度上缩短住院时间和减轻患者经济负担,因此更值得临床推广应用。     

经皮桡动脉行冠状动脉造影护理体会

目的探讨经桡动脉行冠状动脉造影患者的观察和护理。方法分析经桡动脉穿刺行冠状动脉造影的226例患者,男139例,女87例,年龄39~86岁,手术均顺利完成。结果通过观察穿刺处有无渗血、血肿、桡动脉搏动情况、肢端血运情况等护理措施,减少并发症的发生,本组患者中无1例发生手部缺血性坏死或其他并发症。结论经桡动脉行冠状动脉造影术,创伤小,并发症少,患者不需严格卧床,舒适度好,护理方便,节省费用,患者易于接受。     

颞浅动脉与桡动脉有创血压监测在婴幼儿中的应用效果比较

目的 比较经颞浅动脉、桡动脉行有创血压监测在婴幼儿中的应用效果.方法 随机抽取40例病重婴幼儿,每例分别行同侧颞浅动脉与桡动脉穿刺置管监测血压,比较2条动脉一次穿刺成功率、动脉置管成功的平均耗时、拨管后按压时间及置管期间的并发症.结果 颞浅动脉一次穿刺置管成功率显著高于桡动脉,两组比较差异有统计学意义(x2=12.17...     

休克患者股动脉和桡动脉监测有创血压的比较

目的 比较桡动脉和股动脉的平均动脉压在休克患者中是否可以互相替代以及血管活性药物对监测的影响.方法 选取67例有临床指征需行有创动脉压监测的休克患者,分为高剂量血管活性药组和低剂量血管活性药组.同时经股动脉和桡动脉进行有创动脉压监测并记录.结果 桡动脉平均动脉压比股动脉高（3±4）mm Hg,组间比较差异无统计学意义（P＞0.05）.结论 股动脉和桡动脉测量平均动脉压的数据可以互换.即使是接受大剂量血管活性药物的危重患者,进行股动脉穿刺并非是必需的.     

肝移植术后早期桡动脉与股动脉有创血压的差异研究

目的探讨肝移植术后早期患者桡动脉与股动脉有创血压监测的差异性。方法选择2015年1月至2015年12月间我院重症医学科收治的肝移植术后患者22例,对肝移植术后入ICU当时至术后1天内8个时间点,同步进行桡动脉和股动脉有创血压监测。根据股动脉收缩压水平分为3组:A组,收缩压(systolic blood pressure,SBP)90~140 mm Hg(1 mm Hg=0.133 k Pa);B组,SBP140 mm Hg;C组,SBP90 mm Hg,测量桡动脉与股动脉有创血压的差值。结果当股动脉收缩压在正常范围内,股动脉与桡动脉的收缩压、舒张压及平均动脉压无明显差异,差异无统计学意义(P0.05);当股动脉收缩压90 mm Hg时,股动脉的收缩压及平均动脉压明显高于桡动脉压,差异有统计学意义(P0.05);当股动脉收缩压140 mm Hg时,股动脉收缩压明显小于桡动脉,差异有统计学意义(P0.05)。结论肝移植术后患者早期低血压及高血压状态下,桡动脉与股动脉有创血压存在较大差异,低血压状态下桡动脉血压监测易低估患者实际血压水平,而高血压状态下表现为高估患者血压水平。     

不同穿刺点行超声引导下桡动脉穿刺测压在心脏手术中的应用效果

目的探讨不同穿刺点行超声引导下桡动脉穿刺测压在心脏手术中的应用效果。方法选取在宝鸡市中心医院进行心脏外科手术的50例患者,随机分为试验组(25例,桡骨茎突近心端2~3 cm处为穿刺点)和对照组(25例,桡骨茎突内侧动脉搏动最强处为穿刺点)。比较两组患者的超声定位情况、桡动脉穿刺情况及并发症发生情况。结果两组的超声定位时间、一次穿刺成功率、穿刺失败率比较,差异均无统计学意义(P>0.05)。试验组的穿刺点处桡动脉距皮肤垂直距离明显长于对照组(P<0.05)。试验组穿刺部位渗血与肿胀、导管打折或阻塞及需要再次穿刺发生率均明显低于对照组(P<0.05)。结论超声引导下桡动脉穿刺时,将心脏手术的穿刺点定为桡骨茎突近心端2~3cm处具有众多优势,值得临床推广应用。     

Frequency response evaluation of radial artery catheter-manometer systems: Sinusoidal frequency analysis versus flush method

It is well recognized that catheter-manometer systems significantly distort direct radial artery pressure measurements. Sinusoidal frequency analysis and the flush method of assessing the degree of distortion caused by the monitoring system were compared to determine whether these two methods agree in the estimation of natural frequency and damping coefficient. The frequency response of 30 radial artery catheter-manometer systems used for intensive-care unit patients was measured by the flush method and sinusoidal frequency analysis. The monitoring system consisted of a 20-gauge cannula, 150-cm pressure tubing, two plastic stopcocks, a continuous infusion device with fast flush valve, an American Edwards dome, a Hewlett-Packard quartz transducer, and a Hewlett-Packard blood pressure amplifier. Sinusoidal frequency analysis demonstrated second-order underdamped response for all 30 catheter-manometer systems. No secondary resonance peaks were observed up to a frequency of 200 Hz. The measured frequency response demonstrated that the average catheter-manometer system in use in our intensive care unit would cause significant distortion of the radial artery pressure, with the mean natural frequency (fn) of 14.7 ± 3.7 Hz and the mean damping coefficient () of 0.24 ± 0.07. Although the 30 monitoring systems had identical configurations and visible bubbles were carefully removed, a wide range of frequency responses was found (fn=10.2 to 25.3; =0.15 to 0.44). Linear regression analysis demonstrated excellent correlation (r=0.96) for the natural frequency measured by the flush method and sinusoidal frequency analysis. Linear regression for the damping coefficient, on the other hand, demonstrated poor correlation (r=–0.24) for the two measurement methods. Four of the 30 catheter-manometer systems exhibited overdamped behavior by the flush method; sinusoidal frequency analysis demonstrated an underdamped response. The difference in damping coefficient measurements between the two techniques occurs because sinusoidal frequency analysis does not include the effect of the cannula within the radial artery. Because of the position of the tip, this effect can significantly influence the damping coefficient. Since there is a wide variation in responses for debubbled identical systems, it is necessary to test each individual monitoring system used to determine its frequency response. The flush method is more reliable than sinusoidal frequency analysis since it includes the effect of the intraarterial cannula.     

Evaluation of platelet‐rich plasma and hydrostatic pressure regarding cell differentiation in nucleus pulposus tissue engineering

Generation of a biological nucleus pulposus (NP) replacement by tissue engineering appears to be a promising approach for the therapy of early stages of intervertebral disc degeneration. Thereby, autologous mesenchymal stem cells (MSCs) represent an attractive cell source compared to cells of the NP that are already altered in their phenotype due to degenerative processes. This study compares the influence of 3D pellet culture and alginate beads, as well as that of different media compositions, by the addition of human platelet‐rich plasma (PRP) or transforming growth factor (TGF‐β₁) in interaction with hydrostatic pressure on chondrogenic differentiation of human MSCs compared to NP cells. We found that gene expression of the chondrogenic markers aggrecan, collagen type 2 and collagen type 1 and Sox9 was considerably lower in cells cultivated with PRP compared to TGF‐β₁. Immunohistology confirmed this result at protein level in pellet culture. Additionally, the pellet culture system was found to be more suitable than alginate beads. A positive influence of hydrostatic pressure could only be shown for individual donors. In summary, in comparison to TGF‐β₁, human PRP did not induce adequate chondrogenic differentiation for both culture systems and cell types used. The mixture of growth factors in PRP promoted proliferation rather than chondrogenic differentiation. Based on these results, an application of PRP in human NP tissue‐engineering approaches cannot be recommended. Copyright © 2011 John Wiley & Sons, Ltd.     

Vascular tissue engineering of small‐diameter blood vessels: reviewing the electrospinning approach

Vascular tissue engineering is a relevant research field aimed at elaborating and proposing innovative solutions to overcome the drawbacks related to the use of conventional blood vessel substitutes, especially referring to small‐diameter grafts. For this aim, electrospinning can be regarded as a valuable technique to produce novel scaffolds with several functional characteristics that can be usefully tailored for the application discussed here. The reproduction of the natural extracellular matrix obtained by processing bioresorbable polymers, either functionalized or not, is driving the biomedical research towards technical solutions that can lead to an actual therapeutic improvement. In this context, this paper reviews those studies focused on the selection of suitable biomaterials for vascular applications, their microstructure, the cell response to polymeric fibres and the strategies considered so far to modify and therefore enhance the performance of final electrospun scaffolds. Copyright © 2013 John Wiley & Sons, Ltd.     

Brachial artery pulse pressure and common carotid artery diameter: mutually independent associations with mortality in subjects with a recent history of impaired glucose tolerance

BACKGROUND: Decreased large artery function, as reflected by increased brachial artery pulse pressure and increased carotid artery diameter and stiffness, may contribute to the increased mortality risk that is observed in subjects with impaired glucose tolerance. We therefore investigated the association between brachial artery pulse pressure and carotid artery diameter and stiffness, which are estimates of central artery stiffness and arterial remodelling, respectively, and mortality in subjects with a recent history of impaired glucose tolerance. DESIGN: A prospective, population-based cohort study. We measured brachial artery pulse pressure by oscillometric blood pressure measurements, and common carotid artery diameter and distensibility and compliance coefficients by ultrasound in 140 subjects with a recent history of impaired glucose tolerance. During a median 6.6-year follow-up, 16 subjects died. RESULTS: Brachial artery pulse pressure and common carotid artery diameter were positively related to all-cause mortality [hazard ratios per standard deviation, 1.7 (1.2-2.5) and 2.1 (1.3-3.3), respectively]. Results were similar after adjustment for gender, age, waist-to-hip ratio, body mass index, total cholesterol concentration, pre-existent cardiovascular disease, and hypertension, and after additional mutual adjustment. Common carotid artery distensibility and compliance coefficients were not statistically significantly associated with mortality. CONCLUSIONS: Among subjects with a recent history of impaired glucose tolerance, brachial artery pulse pressure and common carotid artery diameter are independently associated with mortality risk. Stiffness of the central arteries may explain the association between pulse pressure and mortality risk. The association between carotid diameter and mortality risk is more likely to reflect arterial remodelling in response to atherosclerosis than that in response to increased local stiffness.     

右下肺动脉直径联合肺动脉压力值在肺心病的诊断价值

目的探讨右下肺动脉直径联合肺动脉压力值在肺心病诊断中的应用价值。方法随机选取我院2014年6月~2016年5月49例确诊肺心病患者为肺心病组;以同期收治的诊断为慢性阻塞性肺疾病的31例患者为COPD组;以及无心肺疾病的30例就诊患者为对照组。分别使用CT测量上述各组的右下肺动脉直径,心脏彩超测量肺动脉压力,比较各组的指标变化,并分析各指标与肺心病病程的关系。结果随着肺心病病程的进展,右下肺动脉直径增大;对照组和肺心病组的主肺动脉直径及肺动脉压力值差异有统计学意义;肺心病组与COPD组、对照组组间的右下肺动脉直径/肺动脉压力值比较,差异均有统计学意义。结论右下肺动脉直径/肺动脉压力值变化与肺心病病程进展程度有关, 右下肺动脉直径/肺动脉压力值是诊断肺心病及其进程的CT监测指标。     

Development and evaluation of axially aligned nanofibres for blood vessel tissue engineering

Biodegradable polymers have been extensively used as scaffolds to regenerate lost tissues. The geometry of the three‐dimensional (3D) scaffolds has an influence on the cellular behaviour. In this study, we have developed 3D‐scaffolds of axially aligned nanofibres of poly(lactic acid) (PLA), poly(caprolactone) (PCL) and PLA:CL (50:50) with diameters in the range 100–400 nm, internal diameter 4 mm, length 4 cm and wall thickness 0.2 mm, by using a dynamic collector. PCL and PLA:CL nanofibres were significantly less hydrophobic than PLA nanofibres. The porosity of PCL (16.23 ± 9.88%) and PLA:CL nanofibres (14.77 ± 3.41%) were comparable, while PLA (6.57 ± 1.54%) nanofibres had lower porosity. The tensile strength and Young's modulus of PLA was significantly lower than PCL and PLA:CL nanofibres and the suture retention strengths of all three scaffolds were comparable. After 4 weeks, the molecular weight of PLA nanofibres was reduced by 53% compared to 44% and 41% for PCL and the PLA:CL nanofibres, respectively. However, the PLA:CL nanofibres maintained their structural integrity even after 28 days. Platelet adhesion studies showed that PCL nanofibres had least tendency to be thrombogenic, while PLA:CL blend nanofibres were highly thrombogenic. Further, in vitro responses such as cell adhesion, proliferation and gene expression of human umbilical vascular endothelial cells (HUVECs) were evaluated. After 6 days of culture, the surfaces of all the three scaffolds were completely covered with cells. Our results demonstrate that expression levels of elastin, angiopoietin, laminin‐4α and ‐5α were upregulated in PCL and PLA:CL nanofibres without the addition of any exogenous factors. Copyright © 2012 John Wiley & Sons, Ltd.     

动脉压迫止血带ZXD-2用于经桡动脉冠状动脉介入术后的效果观察

目的探讨对经桡动脉行冠状动脉介入治疗术后采用动脉压迫止血带ZXD-2加压包扎的效果。方法将300例经桡动脉进行冠状动脉介入术的患者随机分为观察组和对照组各150例。观察组采用动脉压迫止血带ZXD-2加压包扎法,对照组采用弹力胶布加压包扎法,比较两组加压包扎止血的效果。结果2组患者均未出现手部缺血;观察组局部血肿的发生率低于对照组,但差异无统计学意义（P〉0．05）;观察组手指发绀或肿胀、手部胀痛、患者舒适度及SpO：值的变化与对照组相比,差异有统计学意义（P〈0．01）。结论经桡动脉冠状动脉介入术后采用动脉压迫止血带ZXD-2加压包扎止血效果好、并发症低,患者痛苦少、舒适度高,临床应用安全,能够提高医务人员工作效率。