Repair of Sheep Metatarsus Defects by Using Tissue-engineering Technique

Tissue-engineering bone with porous β-tricalcium phosphate (β-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSC) was constructed and the effect of this composite on healing of segmental bone defects was investigated. 10-15 ml bone marrow aspirates were harvested from the iliac crest of sheep, and enriched for MSC by density gradient centrifugation over a Percoll cushion (1.073 g/ml). After cultured and proliferated, tissue-engineering bones were constructed with these cells seeded onto porous β-TCP, and then the constructs were implanted in 8 sheep left metatarsus defect (25 mm in length) as experimental group. Porous β-TCP only were implanted to bridge same size and position defects in 8 sheep as control group, and 25 mm segmental bone defects of left metatarsus were left empty in 4 sheep as blank group. Sheep were sacrificed on the 6th, 12th, and 24th week postoperatively and the implants samples were examined by radiograph, histology, and biomechanical test. The 4 sheep in blank group were sacrificed on the 24th week postoperatively. The results showed that new bone tissues were observed either radiographic or histologically at the defects of experimental group as early as 6th week postoperatively, but not in control group, and osteoid tissue, woven bone and lamellar bone occurred earlier than in control group in which the bone defects were repaired in “creep substitution” way, because of the new bone formed in direct manner without progression through a cartilaginous intermediate. At the 24th week, radiographs and biomechanical test revealed an almost complete repair of the defect of experimental group, only partly in control group. The bone defects in blank group were non-healing at the 24th week. It was concluded that engineering bones constructed with porous β-TCP and autologous MSC were capable of repairing segmental bone defects in sheep metatarsus beyond “creep substitution” way and making it healed earlier. Porous β-TCP being constituted with autologous MSC may be a good option in healing critical segmental bone defects in clinical practice and provide insight for future clinical repair of segmental defect.

Biomaterial and tissue-engineering strategies for the treatment of brain neurodegeneration

The incidence of neurodegenerative diseases is increasing due to changing age demographics and the incidence of sports-related traumatic brain injury is tending to increase over time.Currently approved medicines for neurodegenerative diseases only temporarily reduce the symptoms but cannot cure or delay disease progression.Cell transplantation strategies offer an alternative approach to facilitating central nervous system repair,but efficacy is limited by low in vivo survival rates of cells that are injected in suspension.Transplanting cells that are attached to or encapsulated within a suitable biomaterial construct has the advantage of enhancing cell survival in vivo.A variety of biomaterials have been used to make constructs in different types that included nanoparticles,nanotubes,microspheres,microscale fibrous scaffolds,as well as scaffolds made of gels and in the form of micro-columns.Among these,Tween 80-methoxy poly(ethylene glycol)-poly(lactic-co-glycolic acid)nanoparticles loaded with rhynchophylline had higher transport across a blood-brain barrier model and decreased cell death in an in vitro model of Alzheimer’s disease than rhynchophylline or untreated nanoparticles with rhynchophylline.In an in vitro model of Parkinson’s disease,trans-activating transcriptor bioconjugated with zwitterionic polymer poly(2-methacryoyloxyethyl phosphorylcholine)and protein-based nanoparticles loaded with non-Fe hemin had a similar protective ability as free non-Fe hemin.A positive effect on neuron survival in several in vivo models of Parkinson’s disease was associated with the use of biomaterial constructs such as trans-activating transcriptor bioconjugated with zwitterionic polymer poly(2-methacryoyloxyethyl phosphorylcholine)and protein-based nanoparticles loaded with non-Fe hemin,carbon nanotubes with olfactory bulb stem cells,poly(lactic-co-glycolic acid)microspheres with attached DI-MIAMI cells,ventral midbrain neurons mixed with short fibers of poly-(L-lactic acid)scaffolds and reacted with xyloglucan with/without glial-derived neurotrophic factor,ventral midbrain neurons mixed with Fmoc-DIKVAV hydrogel with/without glial-derived neurotrophic factor.Further studies with in vivo models of Alzheimer’s disease and Parkinson’s disease are warranted especially using transplantation of cells in agarose micro-columns with an inner lumen filled with an appropriate extracellular matrix material.

薄层CT多征象联合多平面重组诊断气管支气管结核

目的 观察薄层CT多征象联合多平面重组(MPR)诊断气管支气管结核(TBTB)的价值。方法 回顾性分析234例接受胸部薄层CT扫描的TBTB患者并行MPR,观察病变直接与间接表现;比较轴位平扫CT(直接观察法)与其联合MPR(联合观察法)的诊断效能。结果 直接观察法诊断TBTB的敏感度、特异度、阳性预测值、阴性预测值及准确率分别为38.88%(201/517)、98.13%(1 789/1 823)、85.53%(201/235)、84.99%(1 789/2 105)及85.04%(1 990/2 340),联合观察法上述各项分别为91.10%(471/517)、98.85%(1 802/1 823)、95.54%(471/493)、97.51%(1 802/1 848)及97.14%(2 273/2 340);2种方法间敏感度、阳性预测值、阴性预测值及准确率差异均有统计学意义(P均<0.001),而特异度差异无统计学意义(P>0.05)。结论 根据薄层CT多征象联合MPR可有效诊断TBTB。

瑞马唑仑复合艾司氯胺酮用于严重气管受压患者清醒气管插管1例

本文报道1例巨大甲状腺肿物致气管严重受压的老年患者的围术期气道管理。采用瑞马唑仑复合艾司氯胺酮镇静镇痛,在清醒镇静和充分表面麻醉下使用纤维支气管镜行气管插管,过程平稳,效果满意。瑞马唑仑复合艾司氯胺酮镇静镇痛为该类患者制定个体化麻醉管理方案提供了新的思路。

胎儿三血管气管切面动脉导管弓左侧血管的鉴别诊断

目的:探讨三血管气管切面(three-vessel trachea view, 3VT)动脉导管弓(ductus arteriosus arch,DAA)左侧血管的超声鉴别诊断流程、主要切面和鉴别要点。方法:回顾性分析我院胎儿心脏超声检查过程中,3VT切面于DAA左侧探及血管的胎儿34例。总结形成DAA左侧血管的疾病类型,归纳鉴别诊断的流程、主要切面和鉴别要点。所有病例均采用出生后新生儿心脏超声证实。结果:(1)根据形成3VT切面DAA左侧血管的病因,将研究对象分为五组:双侧上腔静脉组21例(bilateral superior vena cava, BSVC, 61.8%)、孤立性永存左上腔静脉组2例(isolated left superior vena cava, ILSVC, 5.9%)、左无名静脉弓下走行组3例(subaortic left brachiocephalic vein, SLBCV, 8.8%)、心上型肺静脉异位引流的垂直静脉组3例(vertical vein, VV, 8.8%)和动脉导管壁瘤样膨出组5例(aneurysm of ductus arteriosus, ADA,14.7%)。(2) BSVC鉴别要点是左上腔静脉回流至冠状静脉窦或左心房;ILSVC鉴别要点是仅探及左上腔静脉,右上腔静脉缺如;SLBCV鉴别要点是左无名静脉从主动脉弓下穿行;VV鉴别要点是VV血流方向为从下至上,背离心脏;ADA鉴别要点是动脉导管壁呈瘤样膨出,其频谱为动脉频谱。结论:胎儿3VT切面上DAA左侧血管的鉴别诊断包括BSVC、ILSVC、SLBCV、VV和ADA。超声医师掌握各个疾病的鉴别诊断流程和鉴别要点有助于提高对相关畸形的产前检出和诊断能力。

气管黏液表皮样癌误诊为气管异物1例

1临床资料患儿,男,5岁,因进食后呛咳、发现气管异物4 h于2022-06-17就诊于昆明市儿童医院。患儿家属代诉患儿进食鸡蛋时不慎误吸,随后出现频繁、剧烈呛咳,伴喘息。随即于当地医院就诊,行胸部CT示气管近隆突部2.2 cm处见0.9 cm×0.8 cm稍高密度影,考虑异物(图1A)。诊断为主气管异物梗阻,未行处理,由救护车送至我院ICU。查体:一般情况欠佳,双肺呼吸音粗,可闻及少许痰鸣音,未闻及哮鸣音。入院诊断:气管内异物、呼吸道感染。患儿入ICU后为防止烦躁加重气管异物位置变化,给予舒芬太尼、右美托咪定和丙泊酚持续镇静镇痛,给予头孢唑林钠、奥美拉唑以及地奈德和吸入用盐酸氨溴索雾化。

基于Unet+Attention的胸部CT影像支气管分割算法

目前肺气管分割中,由于CT图像灰度分布复杂,分割目标像素近似,易造成过分割;而且肺气管像素较少,难以得到更多目标特征,造成细小肺气管容易被忽略。针对这些难点,本研究提出结合Unet网络和注意力机制的肺气管分割算法,注意力机制使用的是关注通道域和空间域的卷积块注意力模型(CBAM),该模型提高了气管特征权重。在损失函数方面,针对原始数据中正负样本失衡的问题,引入focal loss损失函数,该函数对标准交叉熵损失函数进行了改进,使难分类样本在训练过程中得到更多关注;最后通过八连通域判断将孤立点去除,保留较大的几个连通域,即最后的肺气管部分。选用由合作医院提供的24组CT影像和43组CTA影像,共计26157张切片图像作为数据集,进行分割实验。结果表明,分割准确率能够达到0.86,过分割率和欠分割率均值为0.28和0.39。经过注意力模块和损失函数的消融实验,在改进前的准确率、过分割率和欠分割率分别为0.81、0.30、0.40,可见其分割效果均不如Unet+Attention方法。与其他常用方法在相同条件下进行比较后,在保证过分割率和欠分割率不变的情况下,所提出的算法得到了最高的准确率,较好地解决了细小气管分割不准确的问题。

1例小脑后下动脉瘤术后并发气道塌陷患者的护理

小脑后下动脉瘤属于后循环动脉瘤之一,包括从小脑后下动脉和椎动脉交界处发出的动脉所产生的动脉瘤,位置毗邻脑干和后组颅神经,瘤体多为非囊状。小脑后下动脉瘤的发生率低,由于特殊的解剖位置及瘤体形态,导致手术治疗难度较大,术后易产生多种严重并发症。临床上常见的手术治疗方式有开颅动脉瘤夹闭术、单纯血管内介入栓塞治疗、血管搭桥术。文章总结1例小脑后下动脉瘤介入栓塞术后并发气道塌陷患者的护理,主要包括气道塌陷高风险识别、气道塌陷的疾病观察及紧急抢救、气道置管期间集束化气道管理、术后拔除气管插管前的评估及护理、气管插管拔管后预见性护理及观察。患者经过积极的抢救和护理,病情好转,转康复医院继续治疗。

基于谱效关系的款冬花祛痰活性成分研究

目的:研究款冬花提取物的高效液相色谱指纹图谱与祛痰作用的谱效关系,筛选款冬花的祛痰活性成分。方法:采用高效液相色谱法建立款冬花提取物的指纹图谱并获得其化学成分含量信息,采用小鼠酚红排泌模型获得款冬花提取物的祛痰药效指标信息,采用偏最小二乘回归法对款冬花提取物的化学成分含量信息与祛痰药效指标信息进行谱效相关分析。结果:初步判断芦丁、异槲皮苷、绿原酸、新绿原酸、隐绿原酸、异绿原酸A、异绿原酸B、异绿原酸C及峰3成分、峰17成分构成款冬花的祛痰活性成分群。结论:款冬花的祛痰作用是多成分共同作用的结果。本研究结果可为关联药效的款冬花质量标准的建立提供参考。

雾化吸入艾司氯胺酮对全身麻醉气管插管患者术后咽喉痛的影响

目的探讨雾化吸入艾司氯胺酮对全身麻醉气管插管(全麻插管)患者术后咽喉痛(POST)的影响。方法选择择期在全麻插管仰卧位下行手术治疗的66例患者作为研究对象,采用随机数字表法将患者分为艾司氯胺酮组(S组)和对照组(C组),每组33例。S组接受艾司氯胺酮25 mg加生理盐水4 mL雾化吸入15 min,C组接受生理盐水5 mL雾化吸入15 min。比较两组患者雾化吸入前即刻、麻醉诱导前即刻、麻醉诱导后5 min、麻醉诱导后30 min、麻醉诱导后60 min、拔除气管导管时、出麻醉复苏室(PACU)时的平均动脉压(MAP)及心率,拔除气管导管后2 h、4 h、8 h、12 h、24 h的POST发生情况,以及不良反应发生情况。结果两组不同时间点MAP及心率差异均无统计学意义(P>0.05)。与雾化吸入前即刻比较,麻醉诱导后5 min、麻醉诱导后30 min、麻醉诱导后60 min、拔除气管导管时、出PACU时C组MAP降低,麻醉诱导前即刻、麻醉诱导后5 min、麻醉诱导后30 min、麻醉诱导后60 min、拔除气管导管时、出PACU时S组MAP及两组心率降低(P<0.05)。S组拔除气管导管后4 h、8 h、12 h、24 h的POST发生率及严重程度低于C组(P<0.05)。S组有1例患者出现恶心呕吐,C组有2例患者出现恶心呕吐,两组不良反应发生率差异无统计学意义(P>0.05)。结论麻醉前雾化吸入艾司氯胺酮可减少全麻插管患者POST的发生率,减轻POST的严重程度,且不良反应发生率低。

应用不同型号气管导管行气管插管对颅脑损伤患者拔管后误吸的影响研究

目的比较应用不同型号气管导管行气管插管(ETT)对颅脑损伤患者拔管后误吸的影响。方法前瞻性纳入2020-05—2021-06于郑州某三甲医院ICU收治的行ETT的颅脑损伤患者(行ETT已超过48 h)。插管24 h内按气管导管型号分为A组(≤7.0 mm)、B组(7.5 mm)和C组(≥8.0 mm)。拔管后6 h内,以纤维支气管镜检查所见,并取口腔和气管标本的量化值α淀粉酶及胃蛋白酶A作为生物学误吸标本,统计误吸发生情况。结果共纳入150例患者,每组50例。3组患者的临床资料差异无统计学意义(P>0.05)。拔管6 h后患者的α淀粉酶水平及胃蛋白酶A浓度为A组<B组<C组,差异有统计学意义(P<0.05);本研究所有患者的胃蛋白酶A均≤200 ng/mL,α淀粉酶≤3314UI/L。纤维支气管镜及生物标记物阳性率均为A组<B组<C组,差异有统计学意义(P<0.05)。纤维支气管镜阳性率≤生物学标本检出阳性率,各组胃蛋白酶检出阳性率均>α淀粉酶,差异有统计学意义(P<0.05)。结论对颅脑损伤患者应用较大型号气管导管行ETT与拔管后发生误吸风险相关;使用较小型号的气管导管可降低拔管后误吸的风险。

Prosthetic reconstruction of the trachea:A historical perspective

This review discusses the history of tracheal reconstruction; from early work to future challenges. The focus is primarily on prosthetic tracheal reconstruction in the form of intraluminal stents, patch repairs, circumferential repairs and replacement of the trachea. A historical perspective of materials used such as foreign materials, autografts, allografts, xenografts and techniques, along with their advantages and disadvantages, is provided.

Carcinoma ex pleomorphic adenoma of the trachea: A case report

BACKGROUND Carcinoma ex pleomorphic adenoma (CXPA) is defined as a malignant salivary gland tumor arising from a primary or recurrent pleomorphic adenoma.Only three cases of CXPA of the trachea have been reported in the literature.CASE SUMMARY We report a case of tracheal CXPA in a 55-year-old woman,who presented with a more than 3-mo history of progressive dyspnea.Computed tomography of the neck and thorax revealed an inhomogeneous,broad-based lesion arising from the tracheal wall on the right side.Endoscopy revealed a subglottic neoplasm causing up to 90% luminal stenosis.The tumor was resected using a highfrequency electrosurgical snare combined with argon plasma coagulation.Histopathology and immunohistochemistry revealed that the tumor was a CXPA of the trachea.CONCLUSION We report the fourth case of tracheal CXPA,and present the first instance of resection of CXPA using high-frequency electrosurgical snare and laser ablation.We also discuss the pathogenesis,diagnosis,histopathology,and systemic therapy of this rare disease.

Transplantation of tissue-engineered human corneal epithelium in limbal stem cell deficiency rabbit models

AIM: To evaluate the biological functions of tissue-engineered human corneal epithelium (TE-HCEP) by corneal transplantation in limbal stem cell deficiency (LSCD) rabbit models. METHODS: TE-HCEPs were reconstructed with DiI-labeled untransfected HCEP cells and denuded amniotic membrane (dAM) in air-liquid interface culture, and their morphology and structure were characterized by hematoxylin-eosin (HE) staining of paraffin-sections, immunohistochemistry and electron microscopy. LSCD models were established by mechanical and alcohol treatment of the left eyes of New Zealand white rabbits, and their eyes were transplanted with TE-HCEPs with dAM surface outside by lamellar keratoplasty (LKP). Corneal transparency, neovascularization, thickness, and epithelial integrality of both traumatic and post transplantation eyes were checked once a week by slit-lamp corneal microscopy, a corneal pachymeter, and periodic acid-Schiff (PAS) staining. At day 120 post surgery, the rabbits in each group were sacrificed and their corneas were examined by DiI label observation, HE staining, immunohistochemistry and electron microscopy. RESULTS: After cultured for 5 days on dAM, HCEP cells, maintaining keratin 3 expression, reconstructed a 6-7 layer TE-HCEP with normal morphology and structure. The traumatic rabbit corneas, entirely opaque, conjunctivalized and with invaded blood vessels, were used as LSCD models for TE-HCEP transplantation. After transplantation, obvious edema was not found in TE-HCEP-transplanted corneas which became more and more transparent, the invaded blood vessels reduced gradually throughout the monitoring period. The corneas decreased to normal thickness on day 25, while those of dAM eyes were over 575 mu m in thickness during the monitoring period. A 45 layer of epithelium consisting of TE-HCEP originated cells attached tightly to the anterior surface of stroma was reconstructed 120 days after TE-HCEP transplantation, which was similar to the normal control eye in morphology and structure. In contrast, intense corneal edema, turbid, invaded blood vessels were found in dAM eyes, and no multilayer epithelium was found but only a few scattered conjunctiva-like cells appeared. CONCLUSION: The TE-HCEP, with similar morphology and structure to those of innate HCEP, could reconstruct a multilayer corneal epithelium with normal functions in restoring corneal transparency and thickness of LSCD rabbits after transplantation. It may be a promising HCEP equivalent for clinical therapy of corneal epithelial disorders.

In vitro reconstruction and characterization of tissue-engineered human corneal epithelium with seeder cells from an untransfected human corneal epithelial cell line

AIM: To demonstrate the morphology and structure of in vitro reconstructed tissue-engineered human corneal epithelium (TE-HCEP) with seeder cells from an untransfected HCEP cell line. METHODS: The TE-HCEPs were reconstructed in vitro with seeder cells from an untransfected HCEP cell line, and scaffold carriers of denuded amniotic membrane (dAM) in air-liquid interface culture for 3, 5, 7 and 9 days, respectively. The specimens were examined with hematoxylin-eosin (HE) staining of paraffin-section, immunocytochemical staining, scanning and transmission electron microscopy. RESULTS: During in vitro reconstruction of TE-HCEP, HCEP cells formed a 3-4, 6-7 and 8-10 layers of an HCEP-like structure on dAMs in air-liquid interface culture for 3, 5 and 7 days, respectively. But the cells deceased to 5-6 layers and the structure of straified epithelium became loose at day 9. And the cells maintained positive expression of marker proteins (keratin 3 and keratin 12), cell-junction proteins (zonula occludens-1, E-cadherin, connexin 43 and integrin beta 1) and membrane transport protein of Na+-K+ ATPase. The HCEP cells in TE-HCEP were rich in microvilli on apical surface and established numerous cell-cell and cell-dAM junctions at day 5. CONCLUSION: The morphology and structure of the reconstructed TE-HCEP were similar to those of HCEP in vivo. The HCEP cells in the reconstructed TE-HCEP maintained the properties of HCEP cells, including abilities of forming intercellular and cell-extracellular matrix junctions and abilities of performing membrane transportation. The untransfected HCEP cells and dAMs could promisingly be used in reconstruction HCEP equivalent for clinical corneal epithelium transplantation.

Bridging sciatic nerve gap using tissue-engineered nerves constructed with neural tissue-committed stem cells derived from bone marrow

BACKGROUND： Schwann cells are the most commonly used cells for tissue-engineered nerves. However, autologous Schwann cells are of limited use in a clinical context, and allogeneic Schwann cells induce immunological rejections. Cells that do not induce immunological rejections and that are relatively easy to acquire are urgently needed for transplantation. OBJECTIVE： To bridge sciatic nerve defects using tissue engineered nerves constructed with neural tissue-committed stem cells （NTCSCs） derived from bone marrow; to observe morphology and function of rat nerves following bridging; to determine the effect of autologous nerve transplantation, which serves as the gold standard for evaluating efficacy of tissue-engineered nerves. DESIGN, TIME AND SETTING： This randomized, controlled, animal experiment was performed in the Anatomical Laboratory and Biomedical Institute of the Second Military Medical University of Chinese PLA between September 2004 and April 2006. MATERIALS： Five Sprague Dawley rats, aged 1 month and weighing 100-150 g, were used for cell culture. Sixty Sprague Dawley rats aged 3 months and weighing 220-250 g, were used to establish neurological defect models. Nestin, neuron-specific enolase （NSE）, glial fibrillary acidic protein （GFAP）, and S-100 antibodies were provided by Santa Cruz Biotechnology, Inc., USA. Acellular nerve grafts were derived from dogs. METHODS： All rats, each with 1-cm gap created in the right sciatic nerve, were randomly assigned to three groups. Each group comprised 20 rats. Autograft nerve transplantation group： the severed 1-cm length nerve segment was reverted, but with the two ends exchanged; the proximal segment was sutured to the distal sciatic nerve stump and the distal segment to the proximal stump. Blank nerve scaffold transplantation group： a 1-cm length acellular nerve graft was used to bridge the sciatic nerve gap. NTCSC engineered nerve transplantation group： a 1-cm length acellular nerve graft, in which NTCSCs were inoculated, was used to bridge the sciatic nerve gap. MAIN OUTCOME MEASURES： Following surgery, sciatic nerve functional index and electrophysiology functions were evaluated for nerve conduction function, including conduction latency, conduction velocity, and action potential peak. Horseradish peroxidase （HRP, 20%） was injected into the gastrocnemius muscle to retrogradely label the 1-4 and L5 nerve ganglions, as well as neurons in the anterior horn of the spinal cord, in the three groups. Positive expression of nestin, NSE, GFAP, and S-100 were determined using an immunofluorescence double-labeling method. RESULTS： NTCSCs differentiated into neuronal-like cells and glial-like cells within 12 weeks after NTCSC engineered nerve transplantation. HRP retrograde tracing displayed a large amount of HRP-labeled neurons in I-45 nerve ganglions, as well as the anterior horn of the spinal cord, in both the autograft nerve transplantation and the NTCSC engineered nerve transplantation groups. However, few HRP-labeled neurons were detected in the blank nerve scaffold transplantation group. Nerve bridges in the autograft nerve transplantation and NTCSC engineered nerve transplantation groups exhibited similar morphology to normal nerves. Neither fractures or broken nerve bridges nor neuromas were found after bridging the sciatic nerve gap with NTCSCs-inoculated acellular nerve graft, indicating repair. Conduction latency, action potential, and conduction velocity in the NTCSC engineered nerve transplantation group were identical to the autograft nerve transplantation group （P 〉 0.05）, but significantly different from the blank nerve scaffold transplantation group （P 〈 0.05）. CONCLUSION＂ NTCSC tissue-engineered nerves were able to repair injured nerves and facilitated restoration of nerve conduction function, similar to autograft nerve transplantation. ＂

A Laminar Flow Model for Mucous Gel Transport in a Cough Machine Simulating Trachea: Effect of Surfactant as a Sol Phase Layer

In this paper, a planar three layer quasisteady laminar flow model is proposed in a cough machine which simulates mucous gel transport in model trachea due to mild forced expiration. The flow is governed by the time dependent pressure gradient generated in trachea due to mild forced expiration. Mucous gel is represented by a viscoelastic Voigt element whereas sol phase fluid and air are considered as Newtonian fluids. For fixed airflow rate, it is shown that when the viscosity of mucous gel is small, mucous gel transport decreases as the elastic modulus increases. However, elastic modulus has negligible effect on large gel viscosity. It is also shown that for fixed airflow rate and fixed airway dimension, mucous gel transport increases with the thickness of sol phase fluid and this increase is further enhanced as the viscosity of sol phase fluid decreases. The effect of surfactant is studied by considering sol phase as surfactant layer which causes slip at the wall and interface of sol phase and mucous gel. It is found that in the presence of surfactant mucous gel transport is enhanced.

Angiogenesis in tissue-engineered nerves evaluated objectively using MICROFIL perfusion and micro-CT scanning

Angiogenesis is a key process in regenerative medicine generally, as well as in the specific field of nerve regeneration. However, no convenient and objective method for evaluating the angiogenesis of tissue-engineered nerves has been reported. In this study, tissue-engineered nerves were constructed in vitro using Schwann cells differentiated from rat skin-derived precursors as supporting cells and chitosan nerve conduits combined with silk fibroin fibers as scaffolds to bridge 10-mm sciatic nerve defects in rats. Four weeks after surgery, three-dimensional blood vessel reconstructions were made through MICROFIL perfusion and micro-CT scanning, and parameter analysis of the tissue-engineered nerves was performed. New blood vessels grew into the tissue-engineered nerves from three main directions： the proximal end, the distal end, and the middle. The parameter analysis of the three-dimensional blood vessel images yielded several parameters, including the number, diameter, connection, and spatial distribution of blood vessels. The new blood vessels were mainly capillaries and microvessels, with diameters ranging from 9 to 301 μm. The blood vessels with diameters from 27 to 155 μm accounted for 82.84% of the new vessels. The microvessels in the tissue-engineered nerves implanted in vivo were relatively well-identified using the MICROFIL perfusion and micro-CT scanning method, which allows the evaluation and comparison of differences and changes of angiogenesis in tissue-engineered nerves implanted in vivo.

Tracheal relaxation of five medicinal plants used in Mexico for the treatment of several diseases

Objective:To assess the relaxant effect of several organic extracts obtained from Agastache mexicana(A.mexicana),Cochlospermum vitifolium(C.vitifolium),Cordia morelosana(C.morelosana),Lepechinia caulescens(L.caulescens)and Talauma mexicana(71 mexicana)used in Mexican traditional medicine for the treatment of several diseases.Methods:Extracts were obtained by maceration at room temperature using hexane,dicliloromethane and methanol for each plant material.The organic extracts were evaluated ex vivo to determine their relaxant activity on the contractions induced by carbaehol(cholinergic receptor agonist,1μmol/L in isolated rat tracheal rings.Results:A total of 15 extracts were evaluated(three for each species).All test samples showed significant relaxant effect,in a concentration-dependent manner,on the contractions induced by 1μmol/L carbachol,with exception of extracts from C.morelosana.Active extracts were less potent than theophylline[phosphodiesterase inhibitor,EC_(50):(28.79±0.82)μg/mL]that was used as positive control.Concentration-response curves revealed that the extracts with more significant effects were dichloromethanic extracts of T.mexhxma[E_(max):(103.03±3.32)%and EC_(50):(159.39±3.72)μg/mL)and C.vitifolium[Emax:(106.58±2.42)%and EC_(50):(219.54±7.61)μg/mL].Finally,hexanic and dichloromethanic extracts from A.mexicana were fully effective but less potent than T.mexicana,and C.vitifolium.Conclusions:Less polar extracts obtained from A.mexicana,71 mexicana and C.vitifolium exhibited greater relaxant effect on tracheal rat rings,which allows us to suggest them as sources for the isolation of bioactive molecules with potential therapeutic value in the treatment of asthma.

Regeneration and Differentiation of Hamster Tracheal Epithelium Used Anti--Brdu Monoclonal Antibody After Mechanical Injury

The ventral quadrant of the tracheal epithelium of the hamster,about one fourth of tracheal mucosa, was denuded by a venous needle reformed.The stains were made with HE, PAS, and PAS-anti Brdu immunohis-tochemic technique. At the 0 h circumference cell number (CCN) was 927. 25.From 6 h post injured the viable cells changed in shapes and migrated from themargin to wound site. By 24 h the wound area was completely covered by a sin-gle layer of non-ciliated flattened cells, then an expotential increassing in cellregeneration occured in wound site by 48 h. The CCN had been restored to thelevel of control (1373), and the proliferative cell, composed of polygonal epi-dermoid metaplasia, 3～4 layers and reached a peak (338.8). The secretoryand ciliated cells appeared gradually from 72 h post injury, the epithelium re-stored to the normal epithelial architecture by one week post injury. In our pre-sent study either in control and non-injured epithelium or in all stages of woundsite about 70% of the Brdu positive cells contained small or confluent PAS posi-tive granules were observed. This fact indicated that secretory cells play a im-portant role in proliferation after mechanical injury and maintaining the normaltracheal pseudostratified epithelium.