搭桥术治疗DeBakey Ⅲ型主动脉夹层的流固耦合数值模拟

目的研究旁路搭桥转流术治疗DeBakey Ⅲ型主动脉夹层的力学机理,并探讨该术式的有效手术方案。方法构建升-腹搭桥和锁-腹搭桥前后通腔型式和盲腔型式的DeBakey Ⅲ型主动脉夹层个性化模型,利用计算流体力学的方法,在生理流动条件下进行流固耦合数值模拟。结果搭桥后假腔的血液流动速度、压力和血管壁位移分别平均下降38.86%、15.347 kPa和39.46%。结论搭桥手术是一种在特定情况下治疗DeBakey Ⅲ型主动脉夹层的有效手术方式,具有很好的临床应用前景。     

主动脉夹层及其移植管搭桥术的二维数值模拟

目的探讨搭桥术对主动脉夹层假腔内血流动力学参数的影响及该术式的治疗有效性。方法利用AutoCAD软件构建DeBakeyⅢ型主动脉夹层及其移植管搭桥术的理想化二维几何模型,然后利用ANSYS软件进行数值模拟,分析计算结果的血流动力学特性。结果在实施搭桥手术后,假腔内的血流速度与压力均小于实施搭桥手术前的值。结论利用旁路搭桥转流术可有效地降低主动脉弓的血压,减轻血流对夹层病变的冲击和压力。由此推之到其对防止夹层破裂,促进夹层局部病变愈合,是一种有效的手术方式。     

基于CT图像胸主动脉夹层与正常胸主动脉内血流动力学模拟对比分析

目的通过对基于CT图像的血流动力学数值模拟获得的患有降主动脉夹层与正常胸主动脉内的血流动力学参数的比较,分析主动脉夹层内血液流动状态与动脉夹层疾病的关系,为阐明主动脉夹层疾病的发病机制提供理论依据。方法患者A为46岁男性,胸主动脉正常;患者B为33岁女性,患有通腔型降主动脉夹层,即通腔形式的DeBakeyⅢ型主动脉夹层。CT图像为DICOM格式,层间距为0.5mm,每片图像的平面分辨率为512×512,像素大小为0.5mm。应用医学图像后处理软件对通过临床获得的CT二维医学图像数据进行处理重构,得到正常和患有降主动脉夹层的胸主动脉三维立体模型并转化为可用于模拟计算的计算机辅助设计（CAD）模型。应用计算流体力学（CFD）软件模拟胸主动脉内血流情况,获得相关血流动力学参数。结果计算出胸主动脉在心动周期内不同时刻的血流动力学参数。结论在心动周期内患有动脉夹层胸主动脉内血流情况较正常胸主动脉内血流情况更为复杂,表现为管壁压力变化较大、夹层开口处出现多个漩涡等现象,表明主动脉夹层内复杂血流情况与主动脉夹层疾病的发病机制存在一定的关系。     

杂交手术治疗累及弓部的主动脉夹层的临床研究

目的 探讨杂交手术治疗累及主动脉弓部的主动脉夹层的方法及疗效.方法 自2009年1月至2012年1月,成都军区总医院共对16例累及主动脉弓部的主动脉夹层患者完成了杂交手术治疗.其中男性11例,女性5例,年龄50～72岁[(56.3±7.1)岁].Stanford A型主动脉夹层(夹层起源于升主动脉)5例,B型夹层(夹层起源于降主动脉)11例,病变均累及主动脉弓,不适宜单独行腔内隔绝治疗.11例采用胸骨正中切口或加颈部切口行升主动脉至头臂动脉旁路移植,5例单纯颈部切口行头臂动脉间旁路移植,然后行股动脉切口逆行主动脉腔内覆膜支架植入.术后即刻行升主动脉造影,术后3个月、1年及2年随访CT资料,观察支架和人工血管通畅情况.结果 所有患者均成功完成血管旁路手术,并植入覆膜支架.术中血管造影证实支架植入定位准确,无明显内漏和移位.主动脉夹层真腔血流恢复正常,旁路血管血流通畅,围手术期无死亡和严重并发症发生.随访16例,随访时间3.0 ～ 48.0个月[(24.O±8.2)个月],所有患者均生存,并恢复正常生活.术后3个月和术后1年、2年复查主动脉增强CT示:支架无移位和内漏,支架内及人工血管旁路血流通畅,未见脑部和肢体的缺血征象.结论 累及弓部的主动脉夹层可根据受累的部位及程度采用不同的杂交手术方法,杂交手术治疗累及主动脉弓部的主动脉夹层安全、有效,能明显减轻患者的创伤和痛苦,该治疗方法扩大了介入覆膜支架腔内治疗的适应证,但远期疗效有待迸一步观察.     

一种可以避免血管再狭窄的双移植管搭桥方式的数值模拟

目的为改善冠状动脉旁路移植管的局部血流动力学,降低血管再狭窄的发生机率,研究一种可以避免血管再狭窄的双移植管搭桥方式。方法利用有限元分析方法,对传统模型和双移植管搭桥模型进行血流动力学模拟仿真,计算缝合区附近的流场、壁面切应力等血流动力学因素的分布情况。结果该双移植管搭桥具有较好的血流动力学分布,明显改善了主搭桥血管与冠状动脉缝合处的血流动力学参数,消除了该部位的涡流和流动停滞点,提高了底面的壁面切应力数值。在辅助搭桥血管与冠状动脉缝合处涡流区长度仅3 mm,与原主搭桥血管缝合处的涡流长度4.5 mm相比明显减小。辅助搭桥管分流了约36%的血液,只有约64%的血液流过了主搭桥管。结论该双移植管搭桥有助于减小内膜增生的发生机率。     

基于计算流体力学的Stanford B型主动脉夹层血流动力学分析

目的通过计算流体力学(computational fluid dynamics, CFD)分析Stanford B型夹层的血流动力学参数,从而有效全面评估疾病。方法基于1例复杂的Stanford B型主动脉夹层患者的增强CTA影像,构建三维模型和血流动力学的数值模拟研究,分析流场速度分布、夹层破口剖面速度分布以及壁面切应力。结果该病例在夹层入口、出口处的血液流速分别最高达到1.2、2 m/s,为进一步预测夹层破裂位置和评估夹层破裂风险提供依据。在夹层破口附近的假腔壁面形成明显的低壁面切应力区,与患者体内血栓位置相一致。结论 CFD能有效分析复杂主动脉夹层的血流动力学特征,获得主动脉弓部及其降主动脉的剪切力与主动脉夹层发生的相关性,有助于指导临床对主动脉进行功能学评估,进而预防疾病发生。     

基于ABAQUS的升主动脉置换术术后血流数值模拟

目的:为研究人工升主动脉置换术治疗Stanford A型主动脉夹层后的血流动力学规律,采集临床CT图像,构建术后个性化主动脉流场几何模型。基于计算流体动力学对其进行数值模拟,得到术后流域壁面压力分布和流速分布两个力学指标,从而分析术后流域规律。方法:采集术后CT图像DICOM文件并应用影像后处理软件MIMICS进行三维重构及优化获得几何模型,再将该流域模型导入网格划分软件进行CFD网格划分,最后将网格文件导入ABAQUS/CFD模块进行多周期瞬态模拟。结果:通过模拟计算,得到术后主动脉在心动周期不同时刻的血流动力学参数。结论:血流动力学参数与边界条件密切相关。主动脉内复杂流场环境与心血管疾病存在一定联系。数值模拟可为人工血管置换术后病情发展提供参考。     

多层裸支架植入主动脉夹层的流固耦合数值模拟

目的提出一种基于理想几何的单向流固耦合计算方法,用于分析多层裸支架干预后主动脉夹层假腔内的血流动力学和假腔壁面应力特征。方法根据假腔是否累及分支动脉将模型分为两类,建立单向流固耦合仿真模型以考察流体域对固体域的影响。模拟不同手术策略干预下,术后假腔内的血流动力学和壁面应力状态,并对血栓形成前后的假腔壁面应力状态进行对比分析。结果忽略支架释放过程对假腔壁面应力的计算影响较小。仅用多层裸支架无法有效缩小假腔内的高流速、高壁面剪切力(wall shear stress,WSS)区域;仅用覆膜支架封堵近端入口,远端将维持高流速、高WSS区域;覆膜支架和多层裸支架联合使用会使假腔内出现最大范围的低流速和低WSS区域,最大程度降低假腔内的压力和壁面应力。与有分支动脉模型相比,无分支动脉模型术后更易形成低流速、低WSS区域,但其术后假腔内血压更高。假腔内血栓的形成可大幅降低血栓覆盖区域的壁面应力。结论所提出的计算方法可同时分析术后假腔内的血流动力学和壁面应力特征,为研究多层裸支架引发假腔血栓化及主动脉再膨大的力学机理提供支撑。     

腔内隔绝术在主动脉瘤外科治疗中的应用

目的：探讨腔内隔绝术治疗主动脉夹层动脉瘤、腹主动脉瘤的操作方法及近期疗效。方法：采用腔内隔绝术治疗主动脉夹层动脉瘤3例、腹主动脉瘤2例。结果：5例主动脉瘤腔内隔绝术均获得成功，术后3例主动脉夹层动脉瘤的假腔立刻消失，2例腹主动脉瘤瘤体成功隔绝。无支架移位；术中发生内漏1例，经及时处理后消失；2例术后出现移植后综合征，经对症处理后缓解。随访3-21个月，无移植物移位及器官缺血，假腔内见血栓形成。结论：腔内隔绝术治疗主动脉瘤创伤小．安全、恢复快，有着较好的近期效果。     

TOF个性化手术规划的血流动力学模拟

目的法洛四联症(tetralogy of Fallot,TOF)是出现在新生儿中一种常见的先天性心脏病,其初期治疗的关键是在主动脉和肺动脉之间建立人工侧支循环,本研究从血流动力学角度探讨升主动脉与右肺动脉吻合的手术方案对TOF治疗的有效性。方法采用计算流体力学的方法对TOF手术模型进行数值模拟,重点考察搭桥管径对手术效果的影响,并根据增流率、分流率、能量损失、压力分布、壁面切应力分布等血流动力学参数对手术方案进行评价。结果实施搭桥手术后,左、右肺动脉出口的血流量有不同程度的增加。结论升主动脉与右肺动脉吻合的搭桥方案,可以在一定程度上缓解肺动脉狭窄造成的血流供给不足。     

Renal dysplasia and asplenia in two sibs

A family is reported in which two sibs, one male and the other female, both died within 24 hours of birth with enlarged polycystic kidneys. Postmortem histology in the second child showed gross renal dysplasia. In both children the pancreas was enlarged, nodular and cystic but the liver appeared macroscopically normal. In the second child, histological examination confirmed pancreatic fibrosis with cystic dilation of ducts, but showed portal fibrosis with bile duct proliferation in the liver.
This combination of findings is very reminiscent of those in a girl and her brother reported by Ivemark et al. (1959). The children reported here also showed absence or hypoplasia of the spleen, cardiac anomalies and other features of the Ivemark syndrome (Ivemark 1955), a quite different, usually sporadic, congenital disorder. It is suggested that the children described here have a distinct lethal congenital disorder, probably inherited in an autosomal recessive manner.     

Schizophrenia in a North Swedish geographical isolate, 1900–1977. Epidemiology, genetics and biochemistry

Over 200 schizophrenic patients belonging to three major and interrelated pedigree complexes have been investigated over the past 30 years in a North Swedish geographically isolated population, presently numbering about 6,000. An intensive investigation of a number of biochemical correlates and genetic markers in a few selected families belonging to one of the major pedigrees has indicated new strategies for the current research program.
Schizophrenia, as defined operationally, is significantly associated with decreased activities of two enzymes (1) blood platelet monoamine oxidase, (2) plasma dopamine-β-hydroxylase, and (3) with the genetic marker Gc² (group specific antigen). Both enzymes are subject to genetic variation. A positive score for linkage between schizophrenia and low plasma DBH activity has been calculated, but, so far, available data are insufficient for discrimination between linkage and partial contribution of genetically controlled low plasma DBH to the pathogenesis of the disease. Alternatively, both mechanisms could be involved.
As a model for continued research, schizophrenia is explained as based on a double dominant-recessive genotype (Aabb), representing a vulnerability which in about 50 % of cases develops into clinical schizophrenia. It is suggested that the dominant mutation (A) operates on or affects MAO activity, and that the recessive genotype (bb) is instrumental in low variates of DBH activity and very likely such variates within the normal range of physiological variation. Moreover, it is suggested that the combined effects of MAO- and DBH-reduced efficiency on the metabolism of e.g. dopamine could be an essential pathogenic mechanism for the schizophrenic illness which is segregating in this population.     

The dominant diseases of modernized societies as omega-3 essential fatty acid deficiency syndrome: Substrate beriberi

About 1900, modern food selection and processing caused widespread $\text{epidemics}$ of the B vitamin deficiency diseases of beriberi and pellagra which, for genetic reasons, often expressed as different diseases ranging from bowel and heart disease to dermatoses and psychoses. But the B vitamins merely help convert essential fatty acids (EFA) into the prostaglandin (PG) tissue regulators and it now turns out that, through hydrogenation, milling and selection of w3-poor southern foods, we have also been systematically depleting, by as much as 90%, a newly discovered trace Nordic EFA (w3) of special importance to primates and sole precursor of the PG3(4) series, even as a concurrent fiber deficiency increases body demand for EFA. Since substrate EFA is processed by many B vitamin catalysts, an EFA deficiency will mimic a $\text{panh}$ypovitaminosis B, i.e., a mixture of $\text{substrate}$ beriberi and $\text{substrate}$ pellagra resembling vitamin beriberi and pellagra but exhibiting as even more diverse $\text{endemic}$ disease. This would consitute a second stage of the Modern Malnutrition and explain why some workers now hold the dominant diseases of modermized societies to be new, nutritionally based, pellagraform yet lipid-related and to range, once again, from heart disease to psychosis. It is an assumption that our dominant diseases are unrelated to each other or are merely revealed by our diagnostic acumen and therapeutic success; and that hydrogenating millions of tons of food oils annually, to destroy the rancidity producing w3-EFA, is safe for $\text{primates}$. Extensive beriberiform disease is reported here in 32 typical cases taken from medical practice which responds strikingly to linseed oil supplements (60% w3-EFA) in confirmation of identical results in Capuchins.     

What will studies of Fulani individuals naturally exposed to malaria teach us about protective immunity to malaria?

There are an estimated over 200 million yearly cases of malaria worldwide. Despite concerted international effort to combat the disease, it still causes approximately half a million deaths every year, the majority of which are young children with Plasmodium falciparum infection in sub-Saharan Africa. Successes are largely attributed to malaria prevention strategies, such as insecticide-treated mosquito nets and indoor spraying, as well as improved access to existing treatments. One important hurdle to new approaches for the treatment and prevention of malaria is our limited understanding of the biology of Plasmodium infection and its complex interaction with the immune system of its human host. Therefore, the elimination of malaria in Africa not only relies on existing tools to reduce malaria burden, but also requires fundamental research to develop innovative approaches. Here, we summarize our discoveries from investigations of ethnic groups of West Africa who have different susceptibility to malaria.     

'Very sore nights and days': the child's experience of illness in early modern England, c.1580-1720

Sick children were ubiquitous in early modern England, and yet they have received very little attention from historians. Taking the elusive perspective of the child, this article explores the physical, emotional, and spiritual experience of illness in England between approximately 1580 and 1720. What was it like being ill and suffering pain? How did the young respond emotionally to the anticipation of death? It is argued that children’s experiences were characterised by profound ambivalence: illness could be terrifying and distressing, but also a source of emotional and spiritual fulfilment and joy. This interpretation challenges the common assumption amongst medical historians that the experiences of early modern patients were utterly miserable. It also sheds light on children’s emotional feelings for their parents, a subject often overlooked in the historiography of childhood. The primary sources used in this article include diaries, autobiographies, letters, the biographies of pious children, printed possession cases, doctors’ casebooks, and theological treatises concerning the afterlife.     

Guidelines for the Validation and Use of Immunoassays for Determination of Introduced Proteins in Biotechnology Enhanced Crops and Derived Food Ingredients

Recent advancements in agricultural biotechnology have created a need for analytical techniques to determine introduced proteins in crops enhanced through modern biotechnology techniques. These proteins are expressed in plant tissues and may be present in food ingredients. Immunoassays are ideally suited for protein detection and may be used as both quantitative and threshold methods. Microplate ELISA and lateral flow devices are two of the most commonly used immunoassay formats for agricultural biotechnology applications. This paper provides general background information and a discussion of criteria for the validation and application of immunochemical methods to the analysis of proteins introduced into plants and food ingredients using biotechnology methods. It is the result of a collaborative effort of members of the Analytical Environmental Immunochemical Consortium. This collaborative effort represents the combined expertise of several organizations to reach consensus on establishing guidelines for the validation and use of immunoassays. Further, the paper offers developers and users a consistent approach to adopting the technology as well as aid in producing accurate and meaningful results.     

Ultracryotomy: development and application (with examples from the yeast cytology) (author's transl)

The preparation steps usually necessary for obtaining ultrathin frozen sections of biological material (chemical prefixation, enclosing, cryoprotective treatment, freezing, sectioning, and post-staining the sections for transmission electron microscopy) are submitted to a critical analysis. The application of cryo-ultramicrotomy, in particularly for cytochemical purposes, is reviewed. Fundamental considerations of chemical prefixation and poststaining are supported by examples from yeast cytology. Furthermore, the efficiency of the cryo-ultramicrotomy (electron optical resolution of ultrastructural details) is demonstrated on yeast cells and protoplasts.     

HLA in North Colombia Chimila Amerindians

HLA-A,-B,-C,-DRB1 and -DQB1 alleles have been studied in Chimila Amerindians from Sabana de San Angel (North Colombian Coast) by using high resolution molecular typing. A frequent extended haplotype was found:HLA-A*24:02-B*51:10-C*15:02-BRB1*04:07-DQB1*03:02 (28.7%) which has also been described in Amerinndian Mayos Mexican population (Mexico, California Gulf, Pacific Ocean). Other haplotypes had already been found in Amerindians from Mexico (Pacific and Atlantic Coast), Peru (highlands and Amazon Basin), Bolivia and North USA. A geographic pattern according to HLA allele or haplotype frequencies is lacking in Amerindians, as already known. Also, five new extended haplotypes were found in Chimila Amerindians. Their HLA-A*24:02 high frequencies characteristic is shared with aboriginal populations of Taiwan; also, HLA-C*01:02 high frequencies are found in New Zealand Maoris, New Caledonians and Kimberly Aborigines from Australia. Finally, this study may show a model of evolutionary factors acting and rising one HLA allele frequency (-A*24:02), but not in others that belong to the same or different HLA loci.     

The universal muscular chamber. A basic unit of the genitourinary, cardiovascular, gastro-intestinal, skeletal, cutaneous, respiratory and other systems, endocameral hypertension; and spasm, the key to their idiopathic diseases and arthropathies

Starting with the integument, we see many organs are contractile sacs or multiples thereof, which tubes or bags constitute the major part of the entire body. Recognition of this basic unit and its characteristics sheds new light, individually and collectively, on many disorders previously considered unrelated. Muscular tears and perforations develop in the walls of these chambers, being no way peculiar to those organs, wherein, hydrochloric acid occurs. So, it is not necessary to explain the absence of excessive acid from patients who exhibit holes in the gastric, uterine, aortic, duodenal, rectal, pulmonary, retina, and other walls. Muscle, not acid is the great common factor relating idiopathic disorders in the gastrointestinal tract to each other and to similar diseases in other systems. When the units are linked together, the lesions tend to appear as arthropathies, i.e. at the joints. Rephrasing common-place observations, frees us from conventional, conceptual cul-de-sacs. An observation is only as good as its interpretation, so all possibilities must be considered, otherwise, we will remain blinded by our misconceptions.