微波消融有效消融体积模型实验研究

针对微波消融治疗需要监测消融区域的温度变化状态和获取有效消融体积的问题,通过离体猪肝实验,分析了消融区域的温升规律并建立了微波消融有效消融体积的数学模型。共进行了112例离体猪肝实验,采用40~70 W的不同微波功率和300~600 s的不同作用时间进行微波消融。实验在70 W微波功率作用下,实时采集了距离微波消融针5、10、15、20 mm处的毁损区域温度,对采用不同微波功率和作用时间得到的有效消融区域的短径、长径及体积数据进行了分析,并利用1stopt软件进行拟合。结果显示,消融区域不同位置的升温速度不同,距离微波针5 mm位置的升温速度为20 mm处的10倍左右;得到了有效消融区域的短径、长径和体积有关微波功率和作用时间的离体组织数学模型。消融区域的温升状态监测和有效消融体积模型的建立,有助于优化微波消融的术前治疗计划和进行实时消融治疗的效果评估。     

基于动态生物组织参数的微波热消融仿真研究

本研究采用基于实验数据的以温度为自变量的动态组织参数,建立了临床常用微波针的仿真模型,并在仿真过程中循环更新组织参数值以实现微波消融过程的动态仿真计算。仿真结果表明该模型的计算结果与实验数据具有较高的一致性,消融区域大小和形状及温度变化与实验结果相吻合。因此,该方法建立的微波消融动态模型,为临床微波消融治疗的手术计划制定、治疗温度实时监控及疗效评估提供了新的依据。     

肝癌微波消融中热损伤参数分析

目的肝癌微波消融研究中,局部热损伤监测和消融仿真计算通常采用Arrhenius模型进行热损伤分析,该模型主要包括活化能Ea和频率因子A两个热损伤参数,然而现有肝脏热损伤参数缺少动力学特性和预测效果对比分析。方法本文采用Arrhenius模型从不同参数所描述的损伤速率和不同温度下的损伤进程方面阐述了其差别,并通过微波消融实验过程的温度数据分析了其对消融损伤的预测效果。结果分析数据表明,Ea(J/mol)和A(s^-1)分别为2.769×10^5和5.51×1041、2.577×10^5和7.39×10^39、1.200×10^5和4.016×10^17的3组参数较适用于消融边界处的损伤计算。结论本文对不同参数的对比有助于指导肝癌消融研究中合理选择热损伤参数进行热损伤分析,从而提高消融手术计划和术中疗效评估的准确性。     

碱金属热消融特性的超声图像纹理刻画

目的碱金属热消融方法为肿瘤微创治疗提供了一种有效手段,该疗法结合了热疗与化疗的双重优势,具有显著的临床实用价值,但在热疗过程中无创监测热凝固区,并在热消融后判别热凝固区进行疗效评估是此消融手术的一个关键。本文拟采用超声图像对热疗进行评估,并选取出变化较大的纹理特征参数作为疗效评估手段。方法首先采集碱金属消融后猪肉组织的B超图像与正常组织的B超图像,利用图像纹理特征分析方法,评估灰度直方图、灰度共生矩阵等19个参数,统计20例实验结果,获得消融后变化率较大的参数,作为组织是否热凝固的判断依据。结果统计数据表明,碱金属热消融前后图像纹理特征变化较大的有灰度直方图中的灰度均值、灰度标准差以及灰度共生矩阵中0°和45°的对比度等4个参数。超声图像纹理特征可间接反映碱金属热消融的效果,并可作为热凝固区的判别依据。当灰度值增大50%及以上、灰度标准差增加100%及以上、灰度共生矩阵中对比度增加30%及以上时,可判定此时组织为凝固组织。结论本文为碱金属热消融方法的疗效评估及实时监测提供了一种有效手段,可为该疗法的快速实用化提供参考。     

微波消融组织B超图像纹理特征参数与温度的相关性

组织温度的无创监测是微波消融技术应用中的一项难题,探讨利用B超图像纹理特征实现微波消融温度监测的可行性.通过微波消融离体猪肝实验,采集不同温度下的B超图像;在此基础上,分析数字减影图像的纹理特征参数(灰度直方图和灰度共生矩阵)与温度的相关性.实验结果表明:组织B超图像纹理参数随着温度变化而变化,在15～90℃范围内图像灰度均值、灰度熵、角二阶矩等与组织温度间具有近似线性关系;利用这种相关性,可实现肿瘤微波消融治疗中组织温度的无创检测.     

超声引导微波消融对离体羊胸腺作用的实验研究

目的将微波消融应用于羊胸腺组织,固定消融功率,分析消融灶大小随消融时间变化的趋势,观察消融灶的大体及组织学变化,比较超声下气化范围和实际消融灶大小的关系。方法新鲜离体羊胸腺50个,羊胸腺最厚处约2~3 cm。根据消融时间不同分为4组,即30 s组、40 s组、50 s组、60 s组。在超声引导下,利用微波消融治疗仪(含冷循环装置)和发射段长5 mm、直径2 mm的电极,设置消融功率为40 W,对离体羊胸腺组织进行不同时间(30、40、50、60 s)的微波消融,测量气化区长径、消融灶长径及短径,并对消融灶行病理学检查。结果随着消融时间延长,气化区长径、消融灶长径、短径和消融灶体积均呈现增大趋势;气化区长径与消融灶长径呈线性相关(r=0.968,P0.05);在相同消融时间下,气化区长径小于消融灶长径(P0.05);消融灶质地变硬,边界清晰,光学显微镜下消融灶内胸腺组织形态失常,其内淋巴细胞难以辨认。结论微波消融羊胸腺组织时,固定微波消融功率,消融灶大小随消融时间延长而增大;所得消融灶长径明显大于超声下气化区长径,临床通过气化范围评估消融程度需要慎重。     

433MHz微波消融天线的设计与实验研究

目的针对915 MHz和2450 MHz微波在肝脏消融中穿透深度低及消融范围受限的问题,提出使用433 MHz微波用于恶性肝肿瘤的消融治疗,通过探索性研究和设计433 MHz频率的微波消融天线,探讨433 MHz微波消融系统对肝组织的消融效果。方法采用缝隙长度分别为18 mm、15 mm和15mm,缝隙间距为10 mm的尺寸设计天线。实时采集消融区域中4个不同旁开距离点的温度,并通过分析有效消融区域的横纵径数据,对所设计的微波天线进行有效评估。结果 433 MHz微波消融天线能形成类葫芦形的消融区域,不仅能有效扩大消融体积,而且能缩短最大横径形成的时间。结论 433 MHz微波消融天线有望应用于恶性肝肿瘤的微波热疗,为研究新频率段的适形微波消融方法提供重要参考。     

颅脑损伤脱水治疗近红外实时监测与评估研究

利用近红外光谱技术实时监测与评估大鼠颅脑损伤脱水治疗效果。采用Feeney’s自由落体法建立大鼠颅脑损伤模型,然后使用不同剂量甘露醇进行脱水治疗,并采集伤后及治疗过程中优化散射系数(μ′s)和颅内压(ICP)的值。结果显示,伤后1h大鼠脑组织发生水肿,伤后72h左右达到峰值,之后开始逐渐减小。注射甘露醇的治疗组μ′s与ICP值在给药后均下降,大剂量甘露醇(2g/kg)平均下降幅度大,平台期持续时间长,总体下降情况更为明显。由此我们得到结论:μ′s和ICP的变化趋势一致,可以代替ICP作为监测脑水肿的参数。     

基于CT的兔肺肿瘤微波消融的温度场研究

目的探索基于三维重建肺肿瘤的微波消融仿真方法,为个性化手术规划模型提供理论基础。方法首先利用Mimics三维重建软件将荷瘤兔CT图像重建成三维数字化模型,同时在COMSOL仿真软件中构建了微波天线模型和理想化肺模型,组成微波消融仿真几何模型。然后采用有限元仿真方法,固定消融功率为30W,设置组织热物性参数及边界条件计算肿瘤组织和肺组织温度场分布,分析得出合适的消融参数。结果成功建立了13.63 mm×11.31 mm的椭球状肺肿瘤的三维模型。基于电磁场与温度场的计算,可以得到肿瘤温度场和肺组织温度场的分布。在使用消融功率30 W/消融时间300 s时,可以使其温度场完全覆盖兔肺肿瘤并预留出安全的消融边界。结论根据个性化肿瘤CT可成功建立其三维肿瘤模型,应用于仿真研究之中可以从肿瘤组织和肺组织温度场分布得到合适的消融参数,该法对降低微波消融肺肿瘤手术难度、改善微波消融肺肿瘤手术效果有着重要意义。     

气冷却天线微波消融热场的实验研究

目的通过研究气冷却天线微波消融热场的特性，探索计算机模拟预测气冷却天线微波温度场的方法。方法在体模实验中精确布置测温点，获取微波温度场的温升规律，在Pennes生物传热方程的基础上，推导建立气冷却天线微波消融的热作用数学模型，对3种加热功率作用时间下热凝固范围和温度分布进行了模拟计算和预测。并在离体猪肝上进行校正检测。结果①3种功率下dT/dt分布各不相同，且后向温升大于前向；②离体猪肝实验时温升曲线及凝固范围实测值与模拟值均有较好的吻合性；③气冷却式微波天线可有效降低杆温，且后向未出现冷区。结论肝脏体模、离体猪肝实验证明，气冷却微波消融在低杆温状态下可以形成较理想的类球体凝固。     

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.     

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.     

The universal muscular chain reaction,muscle spasm,Torsions, ruptures and extravasations. Chameleons of pathology and some manifestations of simple muscular disorders

Most bodily functions require the coordinated actions of complementary and supplementary paired muscle groups. Where this essential muscular cooperation is lacking, hollow organs may burst and others become literally screwed up, giving rise to many similar spastic diseases such as Torticollis, Twisted ovarian cyst, Torsion of the Testis, Volvulus of the intestines, Varicose Veins, Megacolon, Aortamegaly, Scoliosis, Erb's Palsy, Peyronie's Disease, Main-en-Griffe, Undescended Foot (Pes Cavus), Talipes, Strabismus. Spasm is “panenepidemic” and unclassified examples of Torsion Dystonia and Dyskinesia really are as common as debt and taxes.     

Class II HLA in Georgia Caucasus Tbilisi Georgians and their Mediterranean ancestry: The Usko Mediterranean languages

Georgia (or Sakartvelo in its own language) is a South Caucasus Mts. country with its easternmost part is enigmatically named Iberia, like the Iberian Peninsula, which may refer to rivers “Kura” and “Ebro” or their valleys respectively. Most of their inhabitants speak Georgian which is included within Dene-Caucasian group and Usko-Mediterranean subgroup of languages. The latter includes Basque, Berber, ancient Iberian-Tartessian, Etruscan, Hittite, Minoan Lineal A and others. In the present paper, HLA class II -DRB1 and -DQB1 alleles has been studied and extended haplotypes calculated. Most frequent haplotypes are also of Mediterranean origin (i. e.: (A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*51)-DRB1*13:01-DQB1*06:03, or (A*24-B*35)-DRB1*01:01-DQB1*05:01) and DA genetic distances show that closest world populations to Georgians are Mediterraneans. Georgians also show common extended haplotypes ((A*02-B*51)-DRB1*11:01-DQB1*03:01, (A*02-B*13)-DRB1*07:01-DQB1*02:01 and (A*03-B*35)-DRB1*11:01-DQB1*03:01) with Svan people, a secluded population in North Georgia mountains. We can conclude that Georgians belong to a very old Mediterranean substratum according to both linguistics (Usko Mediterranean languages) and HLA genetics.     

Hypo- und Hypermagnesämie aus kardiologischer Sicht

Zusammenfassung Eine Reihe pathologischer Zustände bedingen Magnesiummangel. Zustände mit Hypermagnesämie sind ebenfalls bekannt, doch wesentlich seltener. Für den Kardiologen beachtenswert ist, daß unter Therapie mit bestimmten Diuretica bei Herzinsuffizienz, bei Herzinfarkt, Kardiomyopathie, Digitalisintoxikation und bestimmten Herzrhythmusstörungen Hypomagnesämie beobachtet wurde. Leider kann in der klinischen Routine nur ein extracelluläres Magnesiumdefizit durch Serumbestimmungen gemessen werden; über Magnesiummangel einzelner Organe kann nichts ausgesagt werden. Hinweise für Magnesiummangel geben aber neben der Messung des Serumspiegels Anamnese, klinischer Befund, bestimmte EKG-Veränderungen wie auch evtl. Hypokalämie, ein Zustand, bei dem sich oft — besonders bei Aldosteronismus — parallele Veränderungen zeigten.Tierexperimente deuten darauf hin, daß infarktähnliche Läsionen unter Magnesiummangel entstehen, doch ob Herzinfarkt beim Menschen durch Magnesiummangel ausgelöst werden kann, ist noch ungeklärt. In Leichenherzen zeigte sich im Infarktgebiet neben Calciumakkumulation signifikanter Magnesiumverlust, wobei unklar blieb, ob sich Ursache oder Folge des Infarktes widerspiegelten. Falls ein ursächlicher Zusammenhang besteht, ist er im Myokardstoffwechsel selbst zu suchen, wie bei der Alkoholkardiomyopathie, wo myokardialer Magnesiummangel zumindest als pathogenetischer Teilfaktor anerkannt wird. Andererseits versucht man aber auch Beziehungen zwischen Atherosklerose, Blutgerinnung und Hypomagnesämie herzustellen, in der Meinung, daß Magnesiummangel auch über den coronaren Pathomechanismus des Herzinfarktes wirken könnte. Sicher scheint, daß gewisse EKG-Veränderungen und Herzrhythmusstörungen durch einen irritierten Magnesiumhaushalt bedingt sein können, da sie bei Gabe bzw. Entzug von Magnesium verschwinden. Daß Magnesiummangel die Glykosidtoleranz verringert, wird tierexperimentell bestätigt. Unter Hypomagnesämie bewirkt Acetylstrophanthidin eher und länger Rhythmusstörungen als ohne, außerdem lassen diese sich durch Magnesiumgaben eliminieren. Da in gewissen Fällen spontane und digitalisinduzierte Herzrythmusstörungen durch Magnesiuminjektionen beseitigt wurden, scheint Magnesium als Therapeuticum angebracht. Einsatz verschiedener Magnesiumsalze bei Angina pectoris, degenerativen Herzerkrankungen und Herzinsuffizienz ohne geprüften und offensichtlich gestörten Magnesiumhaushalt ist fragwürdig, weil keine eindeutigen klinischen Erfolgsbeweise vorliegen. Immerhin mag es aber larvierte, durch Serumbestimmungen nicht erfaßbare Mangelzustände geben. Allgemein erscheint es aus kardiologischer Sicht ratsam, den Magnesiumhaushalt zu überwachen und in entsprechenden Fällen auszugleichen, um möglichen Myokardläsionen oder fatalen Herzrhythmusstörungen entgegenzuwirken.     

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.     

Environmental risk factors and their role in the management of atopic dermatitis

Introduction: The etiology of atopic dermatitis (AD) is multifactorial with interaction between genetics, immune and environmental factors.

Areas covered: We review the role of prenatal exposures, irritants and pruritogens, pathogens, climate factors, including temperature, humidity, ultraviolet radiation, outdoor and indoor air pollutants, tobacco smoke exposure, water hardness, urban vs. rural living, diet, breastfeeding, probiotics and prebiotics on AD.

Expert commentary: The increased global prevalence of AD cannot be attributed to genetics alone, suggesting that evolving environmental exposures may trigger and/or flare disease in predisposed individuals. There is a complex interplay between different environmental factors, including individual use of personal care products and exposure to climate, pollution, food and other exogenous factors. Understanding these complex risk factors is crucial to developing targeted interventions to prevent the disease in millions. Moreover, patients require counseling on optimal regimens for minimization of exposure to irritants and pruritogens and other harmful exposures.     

Functional role of fertility α2

Fertility α₂-microglobulin is one of the main proteins expressed between the late lutein phase of the menstrual cycle and the first gestation trimester. It is produced by endometrial secretory glandular epithelium and decidual membrane. It is believed to be involved in the preparation to gestation, conception, normal development of the fetoplacental system, and initiation of labor. The immunomodulating, effect of fertility α₂-microglobulin and its possible involvement in the regulation of fertilization by blocking the spermatozoon reaction with the ovocyte lucid membrane were demonstratedin vitro. The data of structural analysis (appurtenance to lipocalines and unique pattern of N-glycosylation) and analysis of the spatial and temporal parameters of the expression in connection with other events in the organism within the same system of coordinates propated us to investigate the probability of realization of other, so far unknown functions of α₂-microglobulin. The probable mechanisms of realization of the immunomodulating function are analyzed. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 10, pp. 364–373, October 1998