金属支架用于食管肿瘤局部热疗的温度场数值模拟

针对金属支架用于食管肿瘤的局部热疗进行生物传热分析,基于Pennes生物传热方程建立肿瘤组织三维传热模型,采用有限元法模拟计算肿瘤组织中的三维温度场,将数值模拟结果与实验数据比较,吻合较好,最大温度差值为0.7℃.讨论加热温度、血液灌注率和导热系数对温度分布的影响,以及金属支架各关键参数对组织温度的影响规律.结果表明,加热温度升高、血液灌注率降低及导热系数增加,都可提高肿瘤组织的温度,增大组织透热深度,如在加热温度分别为50及48°C时,加热中心组织温度将会相差1℃.支架的长度和直径对组织中的温度分布有较大影响,但支架网格大小对温度分布的影响不大.研究结果可为临床实验探究提供重要的理论依据.     

利用体表瞬变温度无损检测生物体温度依赖型热物性

作者提出一套可用于同时确定生物传热方程─Ｐｅｎｎｅｓ方程中随温度变化的导热系数Ｋ、导温系数ａ、血液灌注率Ｗｂ及代谢热产率Ｑｍ的新方法。文中主要讨论上述参数随温度呈一次方变化的情况，同时考虑空间和温度依赖问题等更复杂的情形亦可用此方法解决。在此基础上，作者发展了一种简单适用且完全无创的检测技术，采用Ｈｏｕｓｅｈｏｌｄｅｒ变换法求超定方程，获得导热率及灌注率关于温度变化的线性表式，结果与有关文献数据吻合。本方法可为研究生物传热学、热生理学以及实现肿瘤热疗中的实时监测打下一定的基础。     

基于热敏电阻探头加热的肿瘤热疗用生物传热模型验证方法

确定适用于特定组织的生物传热模型，对提高肿瘤热疗的效果有重要意义。提出一种新的生物传热模型验证方法。采用数值方法，分析了不同生物传热模型条件下，采用热敏电阻探头加热时，生物组织中温度响应的动态特征。结果表明：通过分析不同血液灌注率情况下组织的惰性时间、组织温度响应曲线是否存在交叉、组织中特定点的温度与热敏电阻探头温度之比的相对大小，可以确定生物组织所适用的生物传热模型。     

深部组织热物理参数的测量及其结果分析

本文阐述了用热干扰法测量机体组织热物性参数和灌注率的实现过程：把热敏电阻探头插入所需测量的组织，给热敏电阻供应电能使其温度升高达到预定值，所需电功率的大小与组织的热物性和血液灌注有关，通过建立热敏电阻珠和测量介质的耦合数学模型，得到计算导热率、扩散率和血液灌的表达式。本文首先用这种方法测量液体介质和离体介质的导热率来验证测量系统的准确性，然后用流动的液体模拟活体组织来测量流动介质的导热率和灌注率。实验结果表明：液体实验结果和离体实验结果与文献基本一致，流动液体的实验结果和我们的分析也完全吻合。     

生物体非均匀热物性测试方法及无损获取生物体皮下温度的近似变分解

本文提出了一套可用于同时测定生物传热方程Ｐｅｎｎｅｓ方程中随空间变化的导热系数Ｋ、血液灌注率Ｗｂ和代谢热产率ｑｍ以及导温系数α的新方法，从而克服了传统生物热物性测试技术中诸如只能测量常物性的Ｋ、Ｗｂ和α以及ｑｍ难以利用Ｐｅｎｎｅｓ方程测出的不足；文中超定方程采用Ｈｏｕｓｅｈｏｌｄｅｒ变换法求解。为了实现对深核体温的无创测取，本文进一步将变分原理引入强非线性生物传热方程的求解，获取了该问题的近似变分解。这些内容可为研究生物传热学、热生理学以及实现肿瘤热疗中的温度监控打下一定的基础。     

激光对生物组织热损伤的数学模拟研究

为了确定激光辐射作用下生物组织的热状态及其热损伤区的大小,本文基于ＶａｓｉｌｉｅｖＶ．Ｎ．＾〔１〕的建模思想,建立了生物组织热损伤的数学模型－－在数学上称之为多边界的Ｓｔｅｆａｎ问题,再将数值解与热损伤实验数据进行比较,结果说明该数学模型对激光外科有指导意义。     

肿瘤射频热疗比吸收率与温度场仿真及影响参数的研究

针对非侵入性射频热疗的SAR及瞬态温度分布进行了物理、数学建模和数值模拟计算。该模型能正确反映电磁波在生物组织内的衰减,在温度场模拟中考虑了血液灌流量随组织温度变化和肿瘤区低血液灌流的特点,使模拟结果更加符合临床实际。我们还对射频热疗电磁能量分布和温度分布的特点、特别是电磁波频率、血液灌流等因素对有效治疗深度的影响作了细致的分析和讨论。对指导射频热疗临床实践具有重要的指导意义。     

基于动物模型的磁感应热疗电磁场与温度场分布的研究

磁感应热疗技术的关键之一就是对肿瘤病变区的温度场分布作相对精确的控制。本研究首先利用AutoCAD三维设计软件构建出接近生物体的动物模型,设计出适用于小动物的磁感应热疗线圈装置,采用Pennes生物传热方程,研究了混合注射和血液灌注效应下温度场分布。结果表明,利用基于有限元的多物理场仿真软件COMSOL,可获得生物体与线圈装置的电磁场分布,可在肿瘤热疗区产生相对理想的温度场分布,其中正常组织体积损伤范围较小,约为0.8%,对于提高肿瘤磁感应热疗的临床安全性及磁感应热疗装置的制造有着指导意义。     

活体组织热物性参数实验及结果分析

利用自行研制的肝癌组织热物性参数和血液灌注率测量装置,以兔子为对象进行了活体实验。经过对实验数据的处理和分析,独创性地将活体兔肝的血液灌注率分为六个等级,为进一步的研究奠定了坚实的基础。     

肿瘤热疗无损测温方法的研究进展

肿瘤热疗(hyperthermia)是利用肿瘤组织对温度敏感性高于正常组织的性质,即人体正常细胞在42. 5～43℃下不会受到损伤,但大部分肿瘤细胞在该温度下会被诱导进入凋亡过程。临床上应用超声、微波或红外等作为加热源,加热并杀死肿瘤组织而使得正常组织基本不受损伤。但是对于如何精确测量肿瘤热疗的温度从而控制热疗剂量仍然是一个难题。本文综述了目前肿瘤热疗过程中电阻抗断层成像(ectrical impedance tomograph,EIT)测温、红外热图引导技术、微波辐射测温法、超声无损测温、磁共振成像测温(magnetic resonance imaging,MRI)等无损测温方法及其研究现状,展望了如何有效精确测量肿瘤热疗时的温度,为控制肿瘤热疗的热剂量提供参考,以期在不伤害正常组织的前提下,使肿瘤组织产生不可逆的损伤。     

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.     

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.     

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.     

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.