伴冠心病的慢性牙周炎患者龈下茵斑中牙周致病菌的检测

目的 观察伴冠心病(coronary heart disease,CHD)的慢性牙周炎患者与慢性牙周炎患者(chronic periodontitis,cP)龈下菌斑中牙周致病菌的分布.方法 收集50例CP患者及50例CP合并CHD患者的龈下菌斑,提取细菌DNA以巢氏聚合酶链反应(nested polymerase chain reaction,Nested PCR)法检测菌斑中牙龈卟啉单胞菌(porphyromonas gingivalis,pg)、中间普氏菌(prevotella intermedia,Pi)、具核梭杆菌(fusobacterium nucleatum,Fn)、伴放线放线杆菌(actinobacillus actinomycetemcomitans,Aa)、福赛斯坦纳菌(tannerella forsythensis,Tf)、齿垢密螺旋体(treponema denficola,Td),并比较6种微生物在CP及CP合并CHD患者物龈下菌斑中的检出率.结果 CP组细菌检出率为:Pg 98%,Pi 92%,Fn 88%,Aa6%,Tf92%和Td98%;CP合并CHD组细菌检测出率为:Pg 100%,Pi 94%,Fn 80%,Aa 14%,Tf96%和Td98%,2组间6种牙周可疑致病菌检出率差别无统计学意义(P>0.05).结论 CP组及cP合并CHD组的龈下菌斑中6种牙周可疑致病菌的分布无明显差别.     

牙周手术治疗对猴Ⅲ度根分叉病变模型龈下菌斑中牙周致病微生物的影响

目的:纵向观察猴在自然状态下(Ⅲ度根分叉病变建立前),根分叉病变建立后牙周手术治疗前,以及手术治疗后6个月时,根分叉部位龈下菌斑中5种牙周可疑致病菌检出率的变化。方法:在猴下颌双侧第二前双尖牙、第一磨牙和第二磨牙制备慢性Ⅲ度根分叉病损后,行牙周手术治疗,3只猴共18个牙位。分别在自然状态下(Ⅲ度根分叉病变建立前),根分叉病变建立后牙周手术治疗前,以及手术治疗后6个月时,取根分叉部位(颊、舌侧)的龈下菌斑。每只猴每时间点有12个样本,3只猴36个菌斑样本,用16SrRNA为基础的PCR技术检测样本中5种牙周可疑致病菌:牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)、福赛坦氏菌(Tannerella forsythensis,Tf)、齿垢密螺旋体(Treponema dinticola,Td)、伴放线放线杆菌(Actinobacillus actinomycetemcomitans,Aa)和具核梭杆菌(Fuso-bacterium nucleatum,Fn)。结果:根分叉病变模型建立后,局部炎症明显,牙周手术后6个月根分叉区牙周组织有一定程度的修复,但局部炎症依然存在,Pg、Tf、Td和Fn的检出率均逐渐显著增加,分别从58.3%、69.4%至88.9%(P<0.01),从47.2%、69.4%至83.3%(P<0.01),从13.9%、36.1%至61.1%(P<0.01),从69.4%、91.7%至91.7%(P<0.05)。Aa的检出率3次取样变化不大(从25.9%、13.9%至33.3%)。同时检出3种以上微生物的检出率从38.9%、61.1%至83.3%(P<0.01),以及红色复合体(Pg+Tf+Td)的同时检出(从8.3%、27.8%至44.4%,P<0.01)也逐渐明显增加。根据术后6个月组织学有无炎症细胞浸润,分成8个感染牙位和10个未感染牙位,术后6个月感染位点与其根分叉病变建立后牙周手术治疗前的红色复合体检出率(87.5%,62.5%)明显高于根分叉病变建立前(0.0%,P<0.01)。虽然均高于非感染部位(60.0%,40.0%),但差异无统计学意义(P均>0.05)。结论:红色复合体(Pg、Tf和Td)在牙周炎的发生和发展中有着重要的作用,Fn则可能是龈下菌斑中的常驻菌,而Aa可能不是慢性牙周炎的主要致病微生物。     

模拟高原缺氧环境对家兔慢性牙周炎龈下菌群种类分布的影响

目的模拟高原缺氧环境,构建兔牙周炎动物模型,研究其龈下菌斑中的主要牙周致病菌与平原组的差异。方法选取清洁级家兔40只完全随机设计分成4组:平原实验组、平原对照组、高原实验组、高原对照组各10只,实验组采用正畸结扎丝结扎双下颌前牙,并给予高糖饮食;高原组置模拟海拔5 000 m的低压氧舱,每天缺氧23 h,持续饲养8周。8周后提取龈下菌斑基因组DNA,用PCR扩增细菌16S rDNA片段方法检测标本中6种牙周炎致病菌包括牙龈卟啉单胞菌(Dorhyromonas gingivalis,Pg)、福赛斯坦纳菌(Bacterides forsythus,Bf)、伴放线放线杆菌(Actinobacillus actinomycetem-comitans,Aa)、中间普氏菌(Prevotella intermedia,Pi)、具核梭杆菌(Fusobacterium nucleatum,Fn)和齿垢密螺旋体(Trepone-ma denticola,Td)的检出率。结果与平原实验组相比,高原实验组的牙龈出血指数、菌斑指数和牙周袋深度均有统计学差异(P<0.05)。牙周可疑致病菌Pg、Bf、Aa、Pi、Fn和Td在高原实验组和平原实验组都可检出,其中高原实验组Fn的检出率80%高于平原实验组20%(P<0.05);平原实验组Pi的检出率70%高于高原实验组15%(P<0.05)。结论高原低氧环境是牙周炎加重的主要原因,Fn与高原牙周炎病变程度加重有一定关系。     

2型糖尿病患者血糖控制对种植体龈沟牙周致病菌的影响

目的: 观察2型糖尿病患者的血糖控制对种植体龈沟牙周致病菌的影响。方法: 收集接受种植牙手术的106例2型糖尿病伴牙周炎的患者,按糖化血红蛋白（HbA1c）值分为HbA1c<8%组（48例）和HbA1c≥8%组（58例）。比较两组患者的年龄、HbA1c比例、菌斑指数、牙周探诊深度。采集入选牙位的龈下菌斑,采用聚合酶链式反应（PCR）检测6种可疑牙周致病菌数量并统计检出率;分析龈下病菌感染与HbA1c的相关性。结果： HbA1c≥8%组患者龈沟出血指数、探诊深度、福塞坦氏菌、中间普氏菌和具核梭杆菌数量和检出率均明显高于HbA1c<8%组（P均<0.05）;牙龈卟啉单胞菌、福塞坦氏菌和具核梭杆菌与患者HbA1c呈正相关（P<0.05）,中间普氏菌与HbA1c呈负相关（P<0.05）。 结论： 糖尿病患者的血糖水平与种植体龈下牙周致病菌菌群的繁殖有相关性。     

早产低体重儿与母亲唾液中牙周致病菌的关系

目的:分析早产低体重儿(preterm low birth weight,PLBW)母亲唾液中主要牙周致病菌,即牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)、福赛坦氏菌(Tannerella forsythia,Tf)、齿垢密螺旋体(Treponema denticola,Td)检出水平及母亲牙周临床状况,探讨母亲牙周炎致病菌与早产低体重儿发生的关系。方法:选取北京4所医院产后1～1.5年的母亲110人,PLBW组母亲72人,21～39岁,正常出生体重组(normal birth weight,NBW)母亲38人,23～38岁。收集唾液样本,记录探诊深度(probing depth,PD)、菌斑指数(plaque index,PLI)、出血指数(bleeding in-dex,BI)及临床附着丧失(clinical attachment loss,CAL)。用PCR方法检测唾液中的Pg、Tf、Td;根据Pg、Tf、Td检出与否分为Pg、Tf、Td阳性和阴性组。结果:(1)PLBW组和NBW组牙周临床指标及Pg、Tf、Td检出率:PLBW组和NBW组CAL分别为0.18(0.00,4.97)mm、0.08(0.00,1.81)mm,两组间差异有统计学意义(P<0.05);Pg检出率分别为94.4%和78.9%,两组间差异有统计学意义(P<0.05);Tf检出率分别为84.7%和94.7%,Td检出率分别为86.1%和89.5%,两组间差异均无统计学意义。(2)Pg、Tf和Td阳性组与阴性组间牙周临床指标、新生儿体重及孕周:Pg阳性组与阴性组间CAL[2.25(0.54,4.00)mm、1.44(0.63,3.80)mm]、PD[(2.47±0.43)mm、(1.94±0.39)mm]、PLI(1.80±0.44、1.36±0.34)、新生儿体重[(2 482.95±813.17)g、(3 425.00±1 024.36)g]差异均有统计学意义(P<0.05);Tf阳性组与阴性组间CAL[0.14(0.00,4.9)mm、0.03(0.00,0.44)mm]、PD[(2.44±0.46)mm、(2.17±0.38)mm]差异有统计学意义(P<0.05);Td阳性组和阴性组间PD[(2.44±0.46)mm、(2.14±0.43)mm]和BI(2.31±0.86、1.83±0.68)差异有统计学意义(P<0.05)。结论:Pg、Tf和Td在两组母亲唾液中检出水平较高,Pg可能与低体重儿发生有关。     

牙周炎患者唾液和龈下菌斑3种厌氧微生物的检测

目的：分析不同类型牙周炎患者唾液和集合龈下菌斑中3种厌氧微生物（包括牙龈卟啉单胞菌、福赛坦氏菌和齿垢密螺旋体）的检出率,并探讨唾液中3种微生物的存在状况与牙周临床指标的关系。方法：收集50例侵袭性牙周炎（aggressive periodontitis, AgP）、48例慢性牙周炎（chronic periodontitis, CP）患者和25例非牙周炎者的非刺激性唾液和集合龈下菌斑,应用PCR技术检测两种样本中的牙龈卟啉单胞菌、福赛坦氏菌和齿垢密螺旋体。结果：3种微生物在AgP组、CP组唾液和龈下菌斑中的检出率均显著高于非牙周炎组（P<0.01）。牙龈卟啉单胞菌在龈下菌斑和唾液中的检出率分别为：AgP组100% vs 100%,CP组93.8% vs 93.8%,非牙周炎组为32% vs 48%。福赛坦氏菌在龈下菌斑和唾液中的检出率为：AgP组96% vs 88%,CP组97.9% vs 89.6%,非牙周炎组为32% vs 24%。齿垢密螺旋体在龈下菌斑和唾液中的检出率为：AgP组94% vs 86%,CP组89.6% vs 70.8%,非牙周炎组12% vs 16%。3种微生物在同一患者两种样本检测结果的一致性均较高。唾液中存在3种微生物均与牙龈出血指数密切相关,其中牙龈卟啉单胞菌的OR值高达13.5。结论：牙龈卟啉单胞菌、福赛坦氏菌和齿垢密螺旋体广泛存在于AgP和CP患者的唾液和龈下菌斑中。唾液中牙龈卟啉单胞菌、福赛坦氏菌和齿垢密螺旋体的检出状况与牙周临床指标密切相关,唾液样本可以用于口腔内牙龈卟啉单胞菌、福赛坦氏菌和齿垢密螺旋体的检测。     

动脉粥样硬化斑块中牙周可疑致病微生物的检测

目的：检测动脉粥样硬化斑块中是否存在牙周致病菌。方法：共选取在手术过程中剥离的、已有动脉粥样硬化改变的动脉内膜标本10例,采用PCR扩增16S rDNA (16S ribosomal DNA)片段的方法,检测7种牙周可疑致病菌,包括牙龈卟啉单胞菌（Porphyromonas gingivalis, Pg）、福赛坦菌（Tannerella forsythia, Tf）、伴放线聚生杆菌（Aggregatibacter actinomycetemcomitans, Aa）、中间普氏菌（Prevotella intermedia, Pi）、变黑普氏菌(Prevotella nigrescen, Pn)、牙密螺旋体（Treponema denticola, Td）及直肠弯曲菌（Campylobacter rectus,Cr）。结果：10例标本中有3例检测出了牙周可疑致病菌,3例样本均检出了Pg,这3例中有1例同时检出了Tf,另1例同时检出了Pn;其余7例标本未检出相关牙周致病菌。结论：动脉粥样硬化斑块样本中检出了部分牙周可疑致病菌,为牙周炎与动脉粥样硬化之间可能存在联系提供了初步证据。     

二氧化锆全瓷冠与钴铬合金烤瓷冠在上颌前牙修复中的应用效果及其对病原菌的影响比较

目的 探讨二氧化锆全瓷冠与钴铬合金烤瓷冠在上颌前牙修复中的应用效果及其对病原菌的影响。方法 选取2019年1月—2020年6月在河北省眼科医院口腔科就诊的80例（80颗）上颌前牙缺损患者为研究对象,并随机分为对照组和观察组,每组40例。对照组采用钴铬合金烤瓷冠修复,观察组采用二氧化锆全瓷冠修复。12个月后,观察两组修复效果,牙龈炎症、出血情况,龈下菌斑标本病原菌检出情况及患者满意度。结果 修复12个月后,观察组较对照组边缘密合度好,修复体颜色与邻牙一致性好,继发龋少（P <0.05）。观察组较对照组牙龈炎症轻（P <0.05）。观察组较对照组牙龈出血少,牙周探诊深度浅（P <0.05）。观察组龈下菌斑标本牙龈卟啉单胞菌、具核梭形杆菌、福赛坦氏菌、伴放线放线杆菌检出率较对照组低（P <0.05）。观察组满意度较对照组高（P <0.05）。结论 相较于钴铬合金烤瓷冠修复,二氧化锆全瓷冠用于上颌前牙修复效果较好,对患者牙周组织及口腔内环境影响较小,有利于提升患者满意度。     

Endothelial progenitor cell transplantation ameliorates elastin breakdown in a Kawasaki disease mouse model

Background  Coronary artery damage from Kawasaki disease (KD) is closely linked to the dysfunction of endothelial progenitor cells (EPCs). The aim of the present study was to evaluate the therapeutic effect of EPCs transplantation in KD model.

Methods  Lactobacillus casei cell wall extract (LCWE)-induced KD model in C57BL/6 mice was established. The model mice were injected intravenously with bone marrow-derived in vitro expanded EPCs. Histological evaluation, number of circulating EPCs and the function of bone marrow EPCs were examined at day 56.

Results  Inflammation was found around the coronary artery of the model mice after 14 days, Elastin breakdown was observed after 56 days. CM-Dil labeled EPCs incorporated into vessel repairing foci was found. At day 56, the number of peripheral EPCs in the KD model group was lower than in EPCs transplanted and control group. The functional index of bone marrow EPCs from the KD model group decreased in proliferation, adhesion and migration. Increased number of circulating EPCs and improved function were observed on the EPCs transplanted group compared with model group.

Conclusion  Exogenously administered EPCs, which represent a novel strategy could prevent the dysfunction of EPCs, accelerate the repair of coronary artery endothelium lesion and decrease the occurrence of aneurysm.

     

Virus profile in children with acute respiratory infections with various severities in Beijing, China

Background Acute respiratory infection （ARI） is one of the most common infectious diseases in infants and young children globally.This study aimed to determine the virus profile in children with ARI presenting with different severities.Methods Clinical specimens collected from children with ARI in Beijing from September 2010 to March 2011 were investigated for 18 respiratory viruses using an xTAG Respiratory Viral Panel Fast （RVP Fast） assay.The Pearson chisquare analysis was used to identify statistical significance.Results Of 270 cases from three groups of ARI patients,including Out-patients,In-patients and patients in the intensive care unit （ICU）,viruses were detected in 176 （65.2％） specimens with the RVP Fast assay.The viral detection rate from the Out-patients group （50.0％） was significantly lower than that from the In-patients （71.1％） and ICU-patients （74.4％） groups.The virus distribution was different between the Out-patients group and the other hospitalized groups,while the virus detection rate and distribution characteristics were similar between the In-patients and ICU-patients groups.The coinfection rates of the Out-patients group,the In-patients group,and the ICU-patients group were 15.6％,50.0％ and 35.8％,respectively.In addition to respiratory syncytial virus （RSV） and adenovirus （ADV）,human rhinovirus （HRV） was frequently detected from children with serious illnesses,followed by human metapneumovirus （hMPV）,human bocavirus （HBoV） and coronaviruses.Parainfluenza virus 3 （PIV3） was detected in children with lower respiratory illness,but rarely from those with serious illnesses in the ICU-patient group.Conclusion In addition to so-called common respiratory viruses,virus detection in children with ARI should include those thoucht to be uncommon respiratory viruses,especially when there are severe ARI-related clinical illnesses.     

Matrix-assisted laser desorption/ionization time of flight mass spectrometry in the genetic basis of systemic lupus erythematosus and the complicating kidney injury

Background It is necessary to develop some innovative methods to reveal and discover the novel (SLE)-related protein molecules.In the present study,matrix-assisted laser desorption/ionization time of f...     

Adjacent segment disease after anterior cervical decompression and fusion: analysis of risk factors on X-ray and magnetic resonance imaging

Background Adjacent segment disease （ASD） is common after cervical fusion.The aim of this study was to evaluate the risk factors for ASD on X-ray and magnetic resonance imaging （MRI）.Methods Patients included in this study had received revision surgeries after developing symptomatic ASD following anterior decompression and fusion.A control group that had not developed ASD was matched 1：1 by follow-up time and fusion segments.Plate-to-disc distances （PDDs）,developmental cervical canal stenosis on X-ray,cervical disc degeneration grading,and cervical disc bulge impingements on preoperative MRI were measured and compared between the ASD group and the control group.Results Thirty-four patients with complete radiographic data were included in the ASD group.The causative segments of ASD included nine cases of C3-4,18 cases of C4-5,three cases of C5-6,and four cases of C6-7.The ASD occurred at the upper adjacent segments in 26 patients and at the lower adjacent segments in eight patients.PDD distributions were similar between the ASD group and the control group.Developmental cervical canal stenosis was a risk factor for ASD,with an odd ratio value of 2.88.Preoperative cervical disc degenerations on MRI were similar between the ASD group and the control group.In the upper-level ASD group,the disc bulge impingement was （19.7±9.7）％,which was significantly higher than that of the control group of （11.8±4.8）％.Conclusions ASD was more likely to develop above the index level of fusion.Developmental cervical canal stenosis and greater disc bulge impingement may be risk factors for the development of ASD.     

牙周致病菌和致龋菌对羟基磷灰石的附着能力

目的研究牙周致病菌和致龋菌对羟基磷灰石(HA)的附着能力。方法将与牙周病和龋病发生密切相关的6种国际参考标准菌株(牙龈卟啉单胞菌、伴放线放线杆菌、具核梭杆菌、变形链球菌、血链球菌、黏性放线菌),分别接种于模拟口腔环境的改良MD-300恒化器中培养,1 h后分离培养HA表面附着的细菌,检测各菌种对HA的附着能力及其相互作用。结果检测菌种中,血链球菌对HA的附着能力最强,其他依次为黏性放线菌、变形链球菌、伴放线放线杆菌、具核梭杆菌和牙龈卟啉单胞菌。血链球菌和黏性放线菌均能增强牙周致病菌对HA的附着能力,变形链球菌降低牙龈卟啉单胞菌的附着能力;所有牙周致病菌均降低血链球菌对HA的附着能力,而对变形链球菌和黏性放线菌无明显影响。结论牙周致病菌对HA的附着能力明显弱于致龋菌,其借助早期定植菌成为牙周生态系的优势菌和牙周病的主要病原菌。     

Platelet function monitoring guided antiplatelet therapy in patients receiving high-risk coronary interventions

Background Large-scale clinical trials have shown that routine monitoring of the platelet function in patients after percutanous coronary intervention （PCI） is not necessary. However, it is still unclear whether patients received high-risk PCI would benefit from a therapy which is guided by a selective platelet function monitoring. This explanatory study sought to assess the benefit of a therapy guided by platelet function monitoring for these patients. Methods Acute coronary syndrome （ACS） patients （n=384） who received high-risk, complex PCI were randomized into two groups. PCI in the two types of lesions described below was defined as high-risk, complex PCI： lesions that could result in severe clinical outcomes if stent thrombosis occurred or lesions at high risk for stent thrombosis. The patients in the conventionally treated group received standard dual antiplatelet therapy. The patients in the platelet function monitoring guided group received an antiplated therapy guided by a modified thromboelastography （TEG） platelet mapping： If inhibition of platelet aggregation （IPA） induced by arachidonic acid （AA） was less than 50% the aspirin dosage was raised to 200 mg/d; if IPA induced by adenosine diphosphate （ADP） was less than 30% the clopidogrel dosage was raised to 150 mg/d, for three months. The primary efficacy endpoint was a composite of myocardial infarction, emergency target vessel revascularization （eTVR）, stent thrombosis, and death in six months. Results This study included 384 patients; 191 and 193 in the conventionally treated group and platelet function monitoring guided group, respectively. No significant differences were observed in the baseline clinical characteristics and interventional data between the two groups. In the platelet function monitoring guided group, the mean IPA induced by AA and ADP were （69.2＋24.5）% （range, 4.8% to 100.0%） and （51.4＋29.8）% （range, 0.2% to 100.0%）, respectively. The AA- induced IPA of forty-three （22.2%）     

Pathogenic analysis in different types of orthopedic implant infections

Background Diversity of orthopedic infections with various local environments affects the pattern and prevalence of pathogens.It is not well-characterized whether different pathogens have different propensity to cause different types of orthopedic infections.We aimed to investigate the frequency of different pathogens derived from orthopedic infections,and determine the relationship between the prevalence of clinical isolates and the type of orthopedic implants,especially focusing on staphylococci.Methods From January 2006 to December 2011,orthopedic infections were identified retrospectively from clinical microbiology laboratory and orthopedic medical records.The sources of orthopedic infections were divided into two main groups：those associated with implants and those not associated with implants.Implants-associated infections were further subdivided into five subgroups：arthroplasty,internal fixation,external fixation,internal and external fixation,and others.We analyzed microbiological spectrum in different groups and subgroups.Antibiotic susceptibility of staphylococci was analyzed.Results Only coagulase-negative staphylococci （CoNS） was significantly more likely to be associated with implantsassociated infections （P=0.029）.The overall pathogens prevalence of arthroplasty was significantly different from other subgroups （P 〈0.05）.65% isolates from external fixation was Gram-negative bacteria.Some percentage （55%） of S.aureus and （83%） CoNS were resistant to methicillin.No resistance to glycopeptide was seen in all of staphylococci.Conclusions Staphylococcus aureus was the most frequent isolates in orthopedic infections but was not associated with the presence or absence of implants.Only CoNS was implants-associated,especially for arthroplasty infection.Cefazolin alone is not enough for orthopedic surgery prophylaxis in settings with a high prevalence of methicillin-resistant staphylococci.     

HLA-G expression in the peripheral blood of live kidney transplant recipients

Background The human leukocyte antigen-G (HLA-G) has been considered to be an important tolerogeneic molecule playing an essential role in maternal-fetal tolerance, upregulated in the context of transplantation, malignancy, and inflammation, and has been correlated with various clinical outcomes. The aim of this study was to investigate the clinical relevance of the expression of membrane HLA-G (mHLA-G), intracellular HLA-G (iHLA-G), and soluble HLA-G (sHLA-G) in the peripheral blood of live kidney transplant recipients.

Methods We compared the expression of the three HLA-G isoforms in three groups, healthy donors (n=20), recipients with acute rejection (n=19), and functioning transplants (n=30). Flow cytometry was used to detect the expression of mHLA-G and iHLA-G in the T lymphocytes of peripheral blood from subjects in the three groups. Enzyme-linked immunosorbent assays were used to detect sHLA-G in the plasma from the three groups.

Results There were no significant differences in mHLA-G and intracellular HLA-G among the three groups, but the sHLA-G plasma level was higher in the functioning group than in the acute rejection or healthy group. We found a subset of CD4+HLA-G+ and CD8+HLA-G+ T lymphocytes with low rates of mHLA-G expression in the peripheral blood of kidney transplantation recipients. Intracellular expression of HLA-G was detected in T lymphocytes. However, there was no correlation between acute rejection and the mHLA-G or intracellular HLA-G expression.

Conclusion sHLA-G was the major isoform in the peripheral blood of live kidney transplant recipients and high sHLA-G levels were associated with allograft acceptance.

     

Short-term safety and efficacy of the biodegradable iron stent in mini-swine coronary arteries

Background To overcome the drawbacks of permanent years. The bioabsorbable polymer vascular scaffold （BVS） stents, biodegradable stents have been studied in recent was the first bioabsorbable stent to undergo clinical trials, demonstrating safety and feasibility in the ABSORB studies. Iron can potentially serve as the biomatedal for biodegradable stents. This study aimed to assess the short4erm safety and efficacy of a biodegradable iron stent in mini-swine coronary arteries. Methods Eight iron stents and eight cobalt chromium alloy （VISION） control stents were randomly implanted into the LAD and RCA of eight healthy mini-swine, respectively. Two stents of the same metal base were implanted into one animal. At 28 days the animals were sacrificed after coronary angiography, and histopathological examinations were performed. Results Histomorphometric measurements showed that mean neointimal thickness （（0.46±0.17） mm vs. （0.45±0.18） mm, P=0.878）, neointimal area （（2.55±0.91） mm2 vs. （3.04±1.15） mm2, P=0.360） and percentage of area stenosis （（44.50±11.40）% vs. （46.00±17.95）%, P=0.845） were not significantly different between the iron stents and VISION stents. There was no inflammation, thrombosis or necrosis in either group. The scanning electron microscopy （SEM） intimal injury scores （0.75±1.04 vs. 0.88±0.99, P=0.809） and number of proliferating cell nuclear antigen （PCNA） positive staining cells were not significantly different between the two groups. The percentage of neointimal coverage by SEM examination was numerically higher in iron stents than in VISION stents （（84.38±14.50）% vs. （65.00±22.04）%, P=0.057）, but the difference was not statistically significant. Iron staining in the tissue surrounding the iron stents at 28 days was positive and the vascular wall adjacent to the iron stent had a brownish tinge, consistent with iron degradation. No abnormal histopathological changes were detected in coronary arteries or major organs. Conclusions The biodegradable iron stent has good biocompatibility and short-term safety and efficacy in the mini- swine coronary artery. Corrosion of iron stents is observed at four weeks and no signs of organ toxicity related to iron degradation were noted.     

Reconstruction of segmental bone defects in the rabbit ulna using periosteum encapsulated mesenchymal stem cells-loaded poly(lactic-co-glycolic acid) scaffolds

Background  Repair of large bone defects remains a challenge for clinicians. The present study investigated the ability of mesenchymal stem cells (MSCs) and/or periosteum-loaded poly(lactic-co-glycolic acid) (PLGA) to promote new bone formation within rabbit ulnar segmental bone defects.

Methods  Rabbit bone marrow-derived MSCs (passage 3) were seeded onto porous PLGA scaffolds. Forty segmental bone defects, each 15 mm in length, were created in the rabbit ulna, from which periosteum was obtained. Bone defects were treated with either PLGA alone (group A), PLGA + MSCs (group B), periosteum-wrapped PLGA (group C) or periosteum-wrapped PLGA/MSCs (group D). At 6 and 12 weeks post-surgery, samples were detected by gross observation, radiological examination (X-ray and micro-CT) and histological analyses.

Results  Group D, comprising both periosteum and MSCs, showed better bone quality, higher X-ray scores and a greater amount of bone volume compared with the other three groups at each time point (P <0.05). No significant differences in radiological scores and amount of bone volume were found between groups B and C (P >0.05), both of which were significantly higher than group A (P <0.05). 

Conclusions  Implanted MSCs combined with periosteum have a synergistic effect on segmental bone regeneration and that periosteum plays a critical role in the process. Fabrication of angiogenic and osteogenic cellular constructs or tissue-engineered periosteum will have broad applications in bone tissue engineering.