微观吸引作用对DNA膜弹性性质的影响

目的研究高价盐下微观吸引作用对DNA膜弹性性质的影响。方法采用Kornyshev静电拉链模型描述高价盐下DNA链间的相互作用势能;采用思想实验法和宏观连续介质弹性杆模型,预测单向应力状态下DNA膜的应力-应变关系、预应力和弹性模量。结果在给定封装条件下,DNA膜具有拉伸预应力和负的弹性模量,预应力为-1.52～1.17 MPa,弹性模量为-4.2～64 MPa。结论与单价盐下的情形不同,随着封装密度和盐浓度的变化,高价盐作用下微观吸引作用使得DNA膜弹性性能展现出非单调的变化,而且拉压弹性性能明显不同,拉伸预应力和压缩预应力以及正负弹性模量会出现转换。研究结果有助于进一步理解病毒复制的机制,并为基因检测和基因治疗提供参考。     

DNA吸附膜热膨胀系数对环境条件的依赖性

目的研究基底上DNA吸附膜热膨胀系数对环境条件的依赖性。方法将DNA吸附分子视为有预应变的宏观连续介质薄膜,建立了DNA膜-基底等效层合梁模型,预测温度载荷作用下DNA-微悬臂梁挠度;采用Parsegian经验势描述DNA吸附膜的介观自由能,利用DNA液晶-基底多尺度挠度模型、思想实验法和等效变形法,建立DNA吸附膜微观结构与其宏观力学性能的跨尺度关系,预测基底上DNA吸附膜的热膨胀系数。结果在给定离子强度条件下,双链DNA吸附膜的热膨胀系数为(0.3~8.05)×10^-4/K,单链DNA吸附膜的热膨胀系数为(1.28~9.33)×10^-4/K。结论在微观作用竞争中起主导作用的构型熵变化决定了DNA吸附膜热膨胀系数对环境条件的依赖性;随着温度或离子浓度或DNA种植密度的增加,DNA膜热膨胀系数减小。研究结果对于基因检测及其调控具有指导意义,并为组织工程中组织器官的性能评估提供参考。     

PIKK调控DNA双链断裂修复的研究进展

生物体细胞基因组完整性受到诸多因素的威胁,包括DNA复制过程中DNA碱基错配、化学物质产生的碱基加合物(adduct formation)和交叉链(cross-links)、紫外线诱导的碱基损伤、电离辐射导致的DNA单链或双链断裂等。DNA双链断裂(DNAdouble-strand break,DSB)被认为是细胞毒性最强的DNA损伤。     

抗双链DNA抗体（dsDNA抗体）检测及临床应用

目的：探讨抗双链DNA抗体(dsDNA抗体)检测在系统性红斑狼疮(SLE)诊断中的意义。方法酶联免疫吸附法联合间接免疫荧光发检测抗双链DNA抗体(dsDNA抗体)。结果 SLE组、其他风湿病组和健康对照组抗双链DNA抗体水平比较,差异均有统计学意义(<0.05)。。抗双链DNA抗体(dsDNA抗体)ELISA方法检测灵敏度为88.5%,特异性为96.6%;抗双链DNA抗体(dsDNA抗体)ELISA方法检测灵敏度为89.6%,特异性为97.7%。结论两种实验方法检测抗双链DNA抗体,有利于诊断和治疗SLE。     

胞外聚合物葡聚糖和DNA对粪肠球菌根管生物膜形成的影响

目的 研究胞外多糖和胞外DNA对粪肠球菌在人牙本质片上黏附并形成生物膜过程中的作用.方法 制备牙本质片,分成葡聚糖酶(Dextranase)组、DNA酶(DNaseI)组和对照组,体外培养获得粪肠球菌的牙本质生物膜标本.采用活菌菌落计数法、激光共聚焦扫描显微镜结合COMSTAT软件分析胞外聚合物对牙本质黏附菌量和生物膜三维结构的影响.结果 相同生物膜膜龄,Dextranase组和DNaseI组粪肠球菌牙本质黏附菌量均少于对照组,差异具有统计学意义(P＜0.05),其中1 h黏附菌量分别下降至对照组的15.61%、18.39%.激光共聚焦显微镜观察到Dextranase和DNaseI对粪肠球菌牙本质生物膜的形成有影响,处理后生物膜结构松散,生物量、底层覆盖率及平均厚度均下降,具有统计学意义(P＜0.0167),其中生物量由(3.95±0.09)μm3/μm2下降至(0.36±0.08)μm3/μm2、(1.05±0.06)μm3/μm2.DNaseI对成熟牙本质生物膜产生显著降解作用,而Dextranase对成熟牙本质生物膜作用不明显.结论 胞外多糖和胞外DNA是粪肠球菌生物膜的重要成分,对其初始黏附和生物膜三维结构起重要作用.     

血管组织工程生物支架材料细胞生物相容性实验研究

目的采用新方法研究天然生物支架材料胶原/透明质酸膜,明胶海绵的细胞相容性。方法应用WST-1法测定平滑肌细胞与材料的粘附率,增殖力,^3H-TDR掺入法测定DNA合成率,BrdU细胞标记免疫组化鉴定,分析组织工程生物支架材料的细胞相容性。结果WST-1法测定,^3H-TDR掺入法测定DNA合成率,BrdU细胞标记结果表明：胶原/透明质酸膜与平滑肌细胞的粘附率最高,细胞的增殖和代谢状况较好,明胶海绵较低。结论应用WST-1法测定,^3H-TDR掺入法测定DNA合成率,BrdU细胞标记方法研究细胞相容性方法简便可行;天然复合生物材料胶原/透明质酸膜具有较理想的细胞相容性。     

基于错配识别蛋白MutS的高特异性的单碱基错配核酸检测方法

目的建立一种基于错配识别蛋白的高特异性核酸检测方法。方法利用蛋白质体外表达和纯化技术获取MutS,并对MutS的错配识别特性进行测定;利用MutS-RCA检测体系对2个碱基错配的不同DNA片段进行检测。结果 MutS蛋白能够有效区分开互补双链和非互补双链DNA,能够稳定结合在非互补双链DNA上,基于MutS的高特异性的单碱基错配核酸检测方法取得了良好的特异性。结论 MutS-RCA检测体系提高了单碱基错配核酸检测的特异性。     

电活性生物膜促进大鼠的体内成骨北大核心

背景:课题组前期研究发现,极化聚偏氟乙烯-三氟乙烯生物膜体外具有调控成骨细胞增殖分化的作用,然而其体内促进骨缺损愈合的作用尚未明确。目的:建立大鼠下颌骨临界骨缺损的动物模型,评价极化聚偏氟乙烯-三氟乙烯在体内促进骨缺损愈合的作用。方法:采用流延法制备聚偏氟乙烯-三氟乙烯生物膜,经由电晕极化处理后使其获得良好且稳定的压电性能,表征极化前后生物膜的物理化学性能、电学性能与生物相容性。在18只Wistar大鼠双侧下颌角制备直径4 mm的临界全厚骨缺损,随机分为3组(n=6),实验组植入极化生物膜,对照组植入未极化生物膜,空白对照组不做处理,术后4,8周取材,采用Micro-CT扫描分析各组的骨形成量,采用组织染色观察各组骨形成情况。实验方案经南方医科大学动物实验伦理委员会批准,伦理批件号:第00225515号。结果与结论:①聚偏氟乙烯-三氟乙烯生物膜极化后的表面形貌、水接触角、弹性模量及最大拉伸强度无明显变化,电学常数为-10 pc/N,表面电势为-83 mV;②细胞增殖-毒性检测结果显示,极化生物膜促进了骨髓间充质干细胞的增殖,未对细胞产生毒性反应;③术后4,8周的Micro-CT结果显示,实验组骨缺损区骨形成量显著高于对照组、空白对照组(P<0.05);④术后4,8周的苏木精-伊红染色显示,实验组骨组织愈合速度与质量明显优于对照组、空白对照组;⑤术后4,8周的免疫组化染色显示,实验组骨缺损区的Runx2表达高于对照组、空白对照组(P<0.05);⑥结果表明,极化生物膜具有良好的理化性能、生物相容性与体内促成骨性能。     

夫西地酸钠联合利福平对表皮葡萄球菌体外培养生物膜的作用

背景：表皮葡萄球菌是材料植入后感染的主要病原体,致病机制是在材料表面形成生物膜,生物膜形成后,单一用药抑制其细菌生长的效果较差。 目的：建立表皮葡萄球菌生物膜体外模型,观察夫西地酸钠联合利福平对表皮葡萄球菌体外培养生物膜的作用。 方法：体外培养生物膜,微量肉汤稀释法检测最低抑菌浓度,将低于最低抑菌浓度的夫西地酸钠和利福平单独或联合使用作用于表皮葡萄球菌早期与成熟期生物膜,观察其对表皮葡萄球菌早期和成熟生物膜的影响。 结果与结论：夫西地酸钠和利福平均可抑制表皮葡萄球菌的黏附和生物膜的形成,对早期及成熟期生物膜内细菌有杀菌效应,二者联合应用后疗效明显优于单独应用(P < 0.05)。提示夫西地酸钠联合利福平可明显抑制抑制表皮葡萄球菌的黏附和生物膜的形成,对早期及成熟期表皮葡萄球菌-生物膜有破坏作用,具有明显杀菌活性,是治疗细菌生物被膜相关感染的良好选择。     

经阴道超声对早孕胚胎绒毛细胞DNA及超微结构的影响

目的研究经阴道超声照射对早期妊娠妇女胚胎的安全性.方法应用经阴道超声照射早孕妇女子宫内的胚囊组织,照射时间长短不同,24h后采取绒毛组织,测定绒毛细胞DNA单链断裂和双链断裂及观察绒毛细胞的超微结构.结果经阴道超声照射5min以内,DNA单链断裂及双链断裂无增加.绒毛出现程度不同的形态学改变.照射10min以上,DNA单链断裂和双链断裂增加.微绒毛扭曲,个别出现断裂、丢失现象,胞质内空泡化明显,粗面内质网扩张.结论对早孕妇女应避免经阴道超声检查,宜采用经腹超声且不超过10min.     

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 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.     

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.     

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.     

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.     

HLA genes in Amerindians from Mexico San Vicente Tancuayalab Teenek/Huastecos

Huastecos or Teenek Amerindians are presently living at North East Mexico (San Luis Potosi State). They have probably one of the most ancient culture of Mexico and Central America together with Mayas and Olmec groups with which also show close relationships. Proximity to Atlantic Ocean/Mexican Gulf originated that Spaniards had very early contact with them at about 1519 CE or before. In the present paper we have aimed to study HLA gene profile which may be useful for HLA and disease epidemiology and transplant programs in Teeneks. HLA-DRB1*04:07, -DRB1*14:06 and -DRB1*04:11 have been found in high frequency like in other Amerindian groups. High frequency typical Amerindians HLA extended haplotypes have been found, such as A*02-B*35-DRB1*04:07-DQB1*03:02; A*68-B*39-DRB1*04:07-DQB1*03:02 and A*02-B*39-DRB1*04:07-DQB1*03:02; also new haplotypes have been described, like A*02-B*52-DRB1*04:11-DQB1*03:02, A*68-B*35-DRB1*14:02-DQB1*03:01 and A*68-B*40-DRB1*16:02-DQB1*03:01. Genetic proximity is observed not only to linguistically close Mayans, but also to Mazatecans, Mixtecans and Zapotecans, who speak an altogether different languages; it shows once more that genes and languages do not correlate. This population was greatly diminished after European contact between 1500 and 1600 years CE; in fact, North and South America First Inhabitants population was brought from 80 down to 8 million people because of diseases (i.e.: measles, smallpox or influenza), slavery and war.     

'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.