不同方法制备脱细胞猪主动脉瓣膜支架的组织结构

背景：理想的脱细胞方法要求既能完全去除供体细胞,降低免疫原性,又能保留天然瓣膜的胶原纤维、弹力纤维等细胞外基质成分,以保持足够的机械强度。 目的：采用不同洗剂制备脱细胞猪主动脉瓣膜支架,对比其组织结构,探讨最为有效的脱细胞瓣膜支架制备方法。 方法：20个新鲜猪主动脉瓣膜随机分为新鲜对照组、去污剂组、酶消化组和去污剂-酶消化组,后3组分别使用Triton X-100、胰蛋白酶以及二者联合的方法制备脱细胞瓣膜支架,对比支架大体形态、苏木精-伊红染色、Mallory-Heidenhain染色和电镜下超微结构的不同。 结果与结论：经脱细胞处理后,去污剂组瓣叶柔软、光滑,苏木精-伊红染色少量核物质存留、纤维排列规整,Mallory-Heidenhain染色胶原纤维和弹性纤维相交错,电镜下呈波浪状排列、原纤维横纹清楚;酶消化组瓣叶局部塌陷,苏木精伊红染色细胞完全去除、纤维排列较紊乱,Mallory-Heidenhain染色胶原纤维和弹性纤维呈网状排列,电镜下纤维部分断裂、原纤维横纹存在;去污剂-酶消化组瓣叶柔软、光滑,苏木精伊红染色细胞完全去除、纤维完整,Mallory-Heidenhain染色胶原纤维和弹性纤维平行排列,电镜下纤维完好,但排列稀疏,原纤维横纹清晰。说明3种方法均可有效去除供体细胞,保持纤维结构相对完整,在完全清除供体细胞并保持纤维支架完整性方面,Triton X-100联合胰蛋白酶的方法更为有效。     

4种肺脏全器官脱细胞支架制备方法的比较

目的分别采用4种不同的方法灌注大鼠肺脏,采集灌注后肺组织大体形态;采取5种不同的染色方法比较脱细胞后肺组织的变化,筛选出较优的脱细胞方法。方法选择SD大鼠12只,雌雄不限,鼠龄8～9周,体质量200～300 g。随机分成4组[3-[(3-胆酰胺丙基)二甲氨基]丙磺酸内盐(CHAPS)组、乙二胺四乙酸二钠盐(EDTA-2Na)组、十二烷基硫酸钠(SDS)组、冻/融组],每组3只。取出整个大鼠肺,用设定的灌注系统采用0.9%氯化钠溶液(生理盐水)适当冲洗其上血液。采用下述脱细胞方法制备:CHAPS组用浓度8 mmol/L CHAPS灌注,EDTA-2Na组用浓度25 mmol/L EDTA-2Na灌注,SDS组用0.1%SDS灌注,冻/融组先冻融后再用0.1%SDS灌注,灌注完毕后均采用0.9%氯化钠溶液200 m L灌注冲洗,最后对脱细胞肺基质分别进行大体形态拍照、苏木精-伊红(HE)染色、弹性纤维(EVG)染色、masson染色、COL-Ⅰ免疫组织化学染色、COL-Ⅲ免疫组织化学染色。结果 CHAPS组肺组织大体形态最为透明;HE染色可见EDTA-2Na组仍残留较多细胞核成分,其余组未见明显的细胞核成分;各组脱细胞后,肺基质构成的肺泡、细支气管等支架结构基本完整。EVG染色可见SDS组和CHAPS组染色较淡,但是SDS组对微结构破坏较大,CHAPS组肺基质保留较完整;COL-Ⅰ免疫组织化学染色可见CHAPS组肺基质保留较其他组完好;COL-Ⅲ免疫组织化学染色可见:SDS组和冻/融组较CHAPS组染色较深,COL-Ⅲ保留较多,且SDS组同冻/融组深浅无明显差别。masson染色可见:CHAPS组和冻/融组肺胶原纤维保留较完整,SDS组肺胶原纤维破坏较大。结论浓度8 mmol/L CHAPS灌注方法是一种较好的制备肺脏脱细胞支架的方法。     

脱细胞基质软骨支架的制备

背景：脱细胞基质材料去除了天然材料中的细胞成分,保留了基质成分,有效降低了天然材料的免疫原性,同时能够保持材料的机械强度。 目的：拟利用洗脱方法去除兔肋软骨中的细胞基质,制备天然生物支架材料。 方法：取新西兰大白兔肋软骨,清除周围组织后随机分组处理,以未经处理的肋软骨作为正常对照组;48 h处理组以去污剂-酶化学消化48 h;96 h处理组以去污剂-酶化学消化96 h,3组均通过苏木精-伊红染色及电镜观察脱细胞效果。同时收集诱导第7天的兔骨髓间充质干细胞3×109 L-1,与同种异体肋软骨脱细胞基质体外复合培养,于第3,7天取复合物行电镜观察细胞在脱细胞基质表面的黏附生长情况。 结果与结论：新鲜肋软骨标本每个软骨陷窝内均有排列紧密的二三个软骨细胞,去污剂-酶化学消化后软骨陷窝内的细胞逐渐脱失,至消化处理96 h后,软骨陷窝内的细胞完全脱失。共培养第3天时,脱细胞基质表面有大量骨髓间充质干细胞分布,细胞为多角形,有伪足伸出,锚定在基质表面,部分区域可见细胞在基质表面增殖分裂;第7天时,脱细胞基质表面大部分均为细胞覆盖,细胞呈扁平状,有多个足突充分伸展,细胞之间互相连接,分泌大量细胞外基质沉积在基质表面,呈冰霜样改变,表明制备的脱细胞基质具有良好的细胞相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

灌注法制备全肾脏脱细胞基质支架的体内生物相容性

背景：应用灌注法制备的大鼠全肾脏脱细胞基质支架具有良好的体外细胞相容性,但其体内生物相容性尚不明确。 目的：应用灌注法制备大鼠全肾脏脱细胞基质支架,检测其体内生物相容性。 方法：应用灌注法制备Wistar大鼠全肾脏脱细胞基质支架,进行以下实验：①急性毒性实验：在小鼠腹腔分别注射全肾脏脱细胞基质支架浸提液、生理盐水及苯酚。②溶血实验：将抗凝新西兰兔血分别与全肾脏脱细胞基质支架浸提液、生理盐水及蒸馏水混合。③热源实验：向新西兰兔耳缘静脉注射全肾脏脱细胞基质支架浸提液。④内皮刺激实验：在新西兰兔皮下注射全肾脏脱细胞基质支架浸提液,观察有无皮肤刺激反应。⑤皮下植入实验：将全肾脏脱细胞基质支架埋入新西兰兔背部皮下。 结果与结论：全灌注法制备的Wistar大鼠全肾脏脱细胞基质支架无细胞残留,未引起全身毒性反应、急性溶血反应、热源反应及皮肤刺激反应,植入兔体内具有良好的组织相容性。说明大鼠全肾脏脱细胞基质材料在动物体内具有很好的生物相容性。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

人去表皮真皮细胞活性及组织结构特征(英文)

背景:研究证实,去表皮的真皮可以作为真皮替代物,在其上接种角质形成细胞后形成表皮结构。但有关真皮替代物细胞生物活性、组织结构特点及基底膜成分分析的研究报道较少。目的:观察人去表皮真皮细胞活性及组织结构特征。方法:将健康成人皮瓣用56℃PBS溶液处理以去除表皮,用液氮连续冻融处理去除真皮中细胞成分,获得去表皮真皮。以组织块培养法观察去表皮真皮细胞活性。以苏木精染色检测去表皮真皮细胞核,以波形蛋白免疫组化检测去表皮真皮成纤维细胞成分。以PAS染色及Ⅳ型胶原免疫组化检测基底膜及其成分。以VG染色检测去表皮真皮胶原纤维,Weigert染色检测弹力纤维,VG与Weigert双染色检测胶原纤维及弹力纤维,透射及扫描电镜观察去表皮真皮超微结构。结果与结论:用组织块培养方法培养的去表皮真皮2周无细胞生长。苏木精-伊红染色显示去表皮真皮中无细胞核、波形蛋白免疫组化显示去表皮真皮中无波形蛋白表达。VG染色显示去表皮真皮胶原纤维染成玫瑰红色,Weigert染色显示去表皮真皮弹力纤维染成紫黑色,双染色进一步显示胶原纤维与弹力纤维均匀排列。去表皮真皮表面及附属器残留部位PAS反应强阳性,Ⅳ型胶原表达明显。透射及扫描电镜下观察到去表皮真皮中胶原﹑弹力纤维交错排列,间有孔隙,相互交织成网。去表皮真皮无活细胞成分,真皮基质表面及附属器管腔壁仍保留糖原﹑Ⅳ型胶原等基底膜成分,真皮基质中富含胶原及弹力纤维,是一种类似在体真皮的三维胶原基质。     

广西猕猴房室结的形态学特征

目的探讨猴房室结的形态学特征,比较物种之间的生物学差异。方法取4例广西猕猴房室结区域,石蜡包埋,连续切片,分别用HE染色、Van Gieson染色和间苯二酚品红液染色,光镜观察其房室结的形态学特征和组织结构。结果猴房室结呈前后长的三角体状。左侧紧贴中心纤维体,右侧有胶原纤维和心房肌覆盖。向前延续为房室束。房室结内存在少量起搏细胞、Purkinje细胞和大量移行细胞。细胞间质内含量有大量胶原纤维和丰富的弹性纤维,两者交织成网。结论广西猕猴房室结的形态较人和其他动物相似,细胞成分较成年人典型,间质内胶原纤维和大量弹力纤维丰富。     

脱细胞猪膀胱支架的构建

文题释义： 脱细胞：生物移植或修补材料制备过程中常用到脱细胞方法,脱细胞能很好的保留组织的成分,降低移植或修补后的免疫原性,同时保持良好的机械性能,在临床上得到较为广泛的应用。 猪膀胱支架：利用不同的脱细胞方法去除猪膀胱组织中的细胞后制备为猪膀胱支架,既保留了细胞外基质的完整性,又可以降低移植后排斥反应,为进一步的对组织工程支架材料的研究奠定了可行的基础。 背景：膀胱修补术是目前临床上治疗膀胱缺损的主要方法之一,同源性组织因各种因素的影响来源较少,组织工程膀胱脱细胞基质受到人们越来越多的关注。猪膀胱脱细胞外基质来源广泛,具备天然的细胞外支架结构,成为组织工程膀胱替代材料研究的热点。 目的：研究脱细胞猪膀胱作为组织工程支架材料的可行性。 方法：取新鲜的猪膀胱,联合液氮冻融、十二烷基硫酸钠、胰蛋白酶脱细胞方法制猪膀胱无细胞基质。按不同脱细胞方法分组：①正常对照组：不做任何处理;②实验组：0.6%胰蛋白酶+5%十二烷基硫酸钠(pH 8.0);③脱细胞对照组：分别用0.75%胰蛋白酶(pH 8.0)、1%胰蛋白酶(pH 8.0)、5%十二烷基硫酸钠(pH 7.6)或10%十二烷基硫酸钠(pH 7.6)处理。通过苏木精-伊红染色和VG染色、DNA定量、α-Gal抗原检测,观察猪膀胱脱细胞效果。 结果与结论：苏木精-伊红染色显示实验组猪膀胱细胞成分已基本去除;VG染色显示实验组完整保留了猪膀胱组织的细胞外基质成分;实验组的DNA残留量仅为(49.84±30.13) μg/g,显著低于几个脱细胞对照组(P < 0.05);同时其α-Gal抗原残留也明显低于脱细胞对照组。提示：应用0.6%胰蛋白酶+5%十二烷基硫酸钠处理猪膀胱,在完整保留猪膀胱组织细胞外基质的同时,可有效去除其细胞成分,为构建脱细胞猪膀胱支架提供一定参考价值。 ORCID: 0000-0003-1004-7390(李芹) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

基因修饰牙龈成纤维细胞及脱细胞真皮基质制备牙周组织工程复合物

背景：前期研究发现人血小板源性生长因子B基因转染的牙龈成纤维细胞能够在体外快速增殖,且能够向胞外分泌血小板源性生长因子BB蛋白。目的：了解人血小板源性生长因子B基因修饰牙龈成纤维细胞植入脱细胞真皮基质后,在体内形成牙周组织工程化复合物的能力。方法：将人血小板源性生长因子B基因转染与未转染的Beagle犬牙龈成纤维细胞分别接种于脱细胞真皮基质上,观察细胞在脱细胞真皮基质上的生长情况。将人血小板源性生长因子B基因转染犬牙龈成纤维细胞-脱细胞真皮基质复合物(实验组)、犬牙龈成纤维细胞-脱细胞真皮基质复合物(对照组)及脱细胞真皮基质(空白组)分别植入裸鼠背部皮下,植入后2,4,8周,取背部标本进行组织学观察。结果与结论：人血小板源性生长因子B基因转染与未转染的犬牙龈成纤维细胞均能在脱细胞真皮基质上良好生长。植入后8周,空白组周围的细胞大面积进入脱细胞真皮基质内,部分脱细胞真皮基质出现完全自体化,尽管细胞进入较多,但新生成的胶原纤维较少,细胞只是占据原有的胶原支架生长;对照组开始出现大面积新生胶原纤维,脱细胞真皮基质上原有的胶原纤维逐步被新生的胶原替代,但原有的胶原结构得到保留;实验组出现大面积完全矿化,可见沿原有胶原支架排列的矿化颗粒。表明接种人血小板源性生长因子B基因修饰牙龈成纤维细胞的脱细胞真皮基质在体内获得了成骨性能。 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

NaOH消蚀法制备胎儿脱细胞真皮基质的研究

目的：探索NaOH消蚀法对胎儿真皮基质的成分及其形态结构的影响。方法：使用NaOH消蚀法制备胎儿皮肤的脱细胞真皮基质(ADM)，应用组织化学和免疫组织化学染色方法检测细胞的余留及细胞外基质成分的破坏情况，应用扫描电镜观察ADM的构筑。结果：NaOH消蚀处理16h即可去除真皮细胞成分。制备的ADM韧性好，勿需戊二醛交联。弹性纤维的含量有所减少而胶原纤维形态完整，排列正常，保留了基本的真皮构筑。HLA—DR呈阴性，Fibronectin(FN)呈弱阳性，Laminin(LN)和Ⅳ型胶原均呈阴性。结论：NaOH消蚀法简易经济，去除细胞成分较彻底，所制备的ADM韧性好，胶原纤维形态完整，排列正常，但对基膜的成分及结构破坏较重。     

珊瑚羟基磷灰石与异体脱细胞真皮基质联合修复牙根尖周组织缺损

背景：慢性根尖周炎症导致根尖周骨质破坏及缺损并不少见,若不能及时消除炎症终止骨吸收和牙龈组织的破坏,修复根尖周组织缺损,最终将导致牙丧失。脱细胞真皮基质和珊瑚羟基磷灰石在动物实验中常用于修复牙周损伤。目的：评价异体脱细胞真皮基质与珊瑚羟基磷灰石两种材料联合修复根尖周组织缺损的临床疗效。方法：选择76例慢性根尖周炎患者作为研究对象,患者等分为实验组和对照组。实验组患者采用异体脱细胞基质与珊瑚羟基磷灰石联合修复根尖周组织缺损;对照组患者不植入任何材料。2组患者均行根尖切除及根尖倒充。修复后1周及6,12个月复诊,通过临床症状和 X 射线片检查评价修复效果。结果与结论：修复1个月后,实验组患者异体脱细胞真皮基质全部存活,因修整瘘管口周围炎性的肉芽组织导致的牙龈组织缺损已经愈合。在修复12个月后,实验组患者的修复有效率明显高于对照组(P < 0.05)。实验组患者修复6个月后骨缺损区阴影基本消失,珊瑚羟基磷灰石颗粒间的透射影减小,出现有一定致密度的影像,提示有新骨长入;12个月后珊瑚羟基磷灰石颗粒密度已接近正常的骨组织密度,与正常骨组织之间有密度移行改变,逐渐与牙槽骨形成骨融合。异体脱细胞基质与珊瑚羟基磷灰石的生物相容性良好。提示异体脱细胞真皮基质与珊瑚羟基磷灰石联合修复根尖周组织缺损具有良好的临床疗效。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

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.