雷帕霉素通过活化MAPK促进神经胶质瘤U87-MG细胞自噬

目的:探讨雷帕霉素(Rapa)对神经胶质瘤U87-MG细胞自噬的相关作用和机制。方法:用Rapa处理U87-MG细胞,分为正常对照(NC)组(0μmol/L Rapa)及Rapa各浓度组(1、2.5、5、10、20和40μmol/L Rapa),MTT实验检测细胞活性,软琼脂集落形成实验和平板集落形成实验检测细胞集落形成能力,Western blot法检测mTOR、p-mTOR、LC3-Ⅱ、beclin-1、p-S6、p70S6K、p-MAPK及GFAP蛋白水平的变化。结果:MTT实验结果显示,Rapa显著抑制U87-MG细胞的活力,并呈现剂量依赖性(P0.05)。软琼脂和平板集落形成实验结果显示,Rapa显著抑制U87-MG细胞集落形成数(P0.05)。Western blot结果显示,Rapa处理后mTOR及p-mTOR蛋白水平降低;自噬标志蛋白LC3-Ⅱ和beclin-1水平显著升高(P0.05);自噬相关信号通路分子p70S6K表达趋势呈抛物线轨迹,差异无统计学意义(P0.05);p-S6表达趋势与p70S6K相反,Rapa干预后p-S6表达显著降低,在40μmol/L Rapa干预后上升至NC组的水平;p-MAPK和GFAP水平显著增高(P0.05)。结论:Rapa通过激活MAPK促进细胞自噬,从而抑制U87-MG细胞增殖。     

氢氧化钠增强雷帕霉素抑制Tsc2缺失的小鼠胚胎成纤维细胞的增殖

目的研究氢氧化钠(NaOH)与雷帕霉素(Rapa)单独或联合处理对Tsc2基因缺失(Tsc2~(-/-))小鼠胚胎成纤维细胞的影响。方法将Tsc2~(-/-)细胞及其对照野生型(WT)细胞按照处理方式分为:对照组、NaOH处理组,Rapa处理组和NaOH+Rapa联合(Combo)处理组。采用MTT法检测细胞增殖能力;克隆形成实验检测细胞集落形成能力;流式细胞测量术检测细胞周期;免疫印迹法检测p-4EBP1、p-S6和S6蛋白表达水平。结果与对照组相比,NaOH组和Rapa组的Tsc2~(-/-)细胞均表现为增殖能力降低、克隆形成数减少(P0.05);仅Rapa组的Tsc2~(-/-)细胞G1期比例升高且p-S6和p-4EBP1的蛋白表达水平降低(P0.05)。与单独的NaOH组和Rapa组相比,Combo组的Tsc2~(-/-)细胞在增殖能力和克隆形成数量上呈进一步降低,G1期细胞的比例呈进一步升高(P0.05),p-S6和p-4EBP1的蛋白表达水平低于NaOH组(P0.05)。结论氢氧化钠(15μmol/L)能增强Rapa抑制Tsc2~(-/-)细胞增殖的效果。     

FK228和雷帕霉素协同促进人乳腺癌细胞凋亡和细胞周期阻滞

目的:探讨组蛋白去乙酰化酶抑制剂(histone deacetylase inhibitor,HDACi)FK228和哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,m TOR)特异性抑制剂雷帕霉素(rapamycin,Rapa)联合应用对体外人乳腺癌细胞株生长和凋亡的影响及其可能的分子机制。方法:以乳腺癌细胞系MDA-MB-435和MCF-7为研究对象,经不同浓度的FK228和雷帕霉素处理后,磺酰罗丹明B(SRB)比色法检测肿瘤细胞的生长抑制率,计算两药的联合指数;Western blotting检测乳腺癌细胞中凋亡相关蛋白、周期调控蛋白以及核酸相关蛋白的表达;流式细胞术检测细胞周期。结果:(1)FK228或雷帕霉素单独使用时均抑制肿瘤细胞生长,抑制率与时间、剂量呈正相关;当总抑制率为50%~70%时联合指数(CI)值小于1,提示两药联合应用具有协同效应;(2)联合用药后,凋亡蛋白表达较单药使用组明显升高(P0.05);同时,p-Akt蛋白表达下降,活化的caspase-3表达上调;(3)联合用药后,周期调控蛋白表达较单药使用组明显下降(P0.05),细胞周期阻滞在G2/M期;联合用药后出现更为显著的H2AX的磷酸化和H3的乙酰化(P0.05)。结论:FK228和雷帕霉素联合给药能协同促进人乳腺癌细胞凋亡和细胞周期阻滞,具有良好的抗肿瘤前景。     

三七总皂苷对神经胶质瘤细胞增殖、迁移及凋亡的影响

目的:探讨三七总皂苷(Panax notoginseng saponins,PNS)对神经胶质瘤U251和U87细胞增殖、迁移和凋亡的影响及其作用机制。方法:将U251和U87细胞各分为两组:对照(control)组和三七总皂苷(PNS)组。CCK-8检测细胞增殖水平;划痕实验检测细胞迁移能力;流式细胞仪检测细胞凋亡水平;Western Blot检测Caspase-3、Bax、Bcl-2、p-AKT、AKT、p-mTOR和mTOR的蛋白表达水平。结果:U251和U87细胞中的检测结果一致。与control组相比,PNS组的细胞增殖能力和迁移能力均显著下降(P0.05);细胞凋亡率显著升高(P0.05);Bcl-2的蛋白表达水平显著下调(P0.05),而Bax和Caspase-3的表达水平显著上调(P0.05);p-Akt和p-mTOR的蛋白表达水平下降,且差异具有显著性(P0.05)。结论:PNS能够抑制U251和U87细胞的增殖和迁移,促进细胞凋亡,这可能与PI3K-Akt-mTOR信号通路的抑制有关。     

MiR-429通过CRKL靶向作用对U87胶质瘤细胞增殖和凋亡的影响

目的研究miR-429对人U87胶质瘤细胞增殖和凋亡的影响及可能机制。方法培养人U87胶质瘤细胞,应用LipofectamineLTX试剂将pre-miR-429质粒载体以及anti-miR-429质粒载体分别稳定转染人U87胶质瘤细胞;应用Real-time-PCR验证转染效率;应用CCK-8试剂盒检测miR-429对人U87胶质瘤细胞增殖能力的影响;应用Real-time PCR和Western blot检测人U87胶质瘤细胞中接头蛋白CRKL(v-crk avian sarcoma virus CT10oncogene homolog-like,CRKL)的mRNA和蛋白表达含量变化;将CRKL分别转染至U87胶质瘤细胞和miR-429过表达的U87胶质瘤细胞,应用CCK-8试剂盒检测人U87胶质瘤细胞增殖,应用流式细胞仪检测细胞凋亡的变化,应用Western blot法检测凋亡相关蛋白caspase-3和Bcl-2的蛋白表达变化。结果与对照组相比,miR-429过表达显著抑制了人U87胶质瘤细胞增殖,明显诱导了凋亡发生,显著降低了CRKLmRNA和蛋白在人U87胶质瘤细胞的表达水平,caspase-3的表达水平显著上调,Bcl-2的表达水平显著降低。CRKL过表达显著增强了人U87胶质瘤细胞增殖能力并且抑制了细胞凋亡,caspase-3的表达水平显著下调,Bcl-2的表达水平显著增强;CRKL过表达有效阻断了miR-429上调caspase-3、降低Bcl-2的作用,有效阻断了miR-429抑制U87胶质瘤细胞增殖和诱导凋亡的作用。结论 MiR-429抑制CRKL从而降低人U87胶质瘤细胞的增殖能力,诱导细胞凋亡。     

黄芩素和U0126体外抗人乳腺癌的作用及机制研究

目的:探讨黄芩素和U0126体外对乳腺癌的作用及其机制。方法:用黄芩素、U0126单独处理以及二者联合处理人乳腺癌细胞株MCF-7细胞,采用CCK8检测细胞增殖变化;流式细胞术检测MCF-7细胞周期以及凋亡变化;显微镜观察细胞数量变化;TUNEL法检测细胞凋亡改变;划痕实验分析细胞迁移情况;Western blot实验检测细胞凋亡相关因子的蛋白水平变化,分析黄芩素与U0126对乳腺癌细胞的增殖、凋亡和迁移的影响。结果:黄芩素或U0126可抑制细胞的增殖且具有浓度依赖性(P0.05);黄芩素阻滞MCF-7细胞周期进入S期,增加G0~G1期细胞比例(P0.05),降低S期细胞比例(P0.05),诱导细胞凋亡(P0.05);降低ERK1/2和JNK蛋白的磷酸化水平和CyclinD 1的蛋白水平表达;黄芩素与U0126联合处理MCF-7细胞,与黄芩素单独处理组相比较,S期细胞比例明显降低(P0.05),细胞凋亡更加明显(P0.05),ERK1/2和JNK的磷酸化水平(P0.05)、CyclinD 1的蛋白表达量降低更加明显(P0.05);同时黄芩素可有效抑制人乳腺癌细胞株MCF-7细胞的迁移(P0.05)。结论:黄芩素和U0126通过降低ERK1/2、JNK的磷酸化水平表达,降低CyclinD 1的水平表达,有效抑制MCF-7细胞增殖和迁移,诱导MCF-7细胞凋亡并且二者具有协同作用。因此,黄芩素和U0126联合有望用于临床治疗乳腺癌。     

小白菊内酯增强PKC抑制剂诱导的人胃肠道间质瘤细胞系凋亡

目的探讨小白菊内酯(PTL)及蛋白激酶C抑制剂(PKC抑制剂)对人胃肠道间质瘤(GIST)细胞增殖和凋亡的影响及其机制。方法人GIST细胞系进行体外培养,用MTT法测GIST细胞增殖抑制率;用流式细胞技术检测GIST细胞的早期凋亡率;Western blot法检测GRP78与GADD153内质网应激相关蛋白的表达。实验分为对照组、PTL组、PKC抑制剂组及PTL和PKC抑制剂联合用药组。结果 PTL和PKC抑制剂联合用药对1)GIST细胞的抑制作用明显高于单独用药组(P0.05);2)GIST细胞的早期凋亡率明显高于单独用药组(P0.05);3)内质网应激相关蛋白GRP78与GADD153的表达明显高于单独用药组(P0.05)。结论 PTL和PKC抑制剂联合用药促进GIST细胞凋亡,其机制与内质网应激途径介导的凋亡有关。     

沉默环状RNA BACH2抑制胶质瘤细胞的恶性生物学行为

目的 检测环状RNA(circular RNA)BACH2在胶质瘤组织和胶质瘤细胞U87中的表达水平,探讨其对U87细胞增殖、迁移、侵袭、凋亡的影响.方法 26例胶质瘤患者术中取肿瘤标本,应用实时PCR方法检测circBACH2在胶质瘤组织和U87细胞的表达.转染circBACH2沉默质粒载体后,CCK-8方法检测U87细胞增殖,Transwell小室方法检测U87细胞的迁移及侵袭,流式细胞仪检测U87细胞的凋亡.结果 circBACH2在胶质瘤组织和U87细胞中高表达(P＜0.01).circBACH2沉默可以抑制U87细胞的增殖、迁移和侵袭能力,促进凋亡(P＜0.01).结论 circBACH2在胶质瘤组织和U87细胞中表达上调,促进U87细胞增殖、迁移和侵袭,抑制细胞凋亡.     

雷帕霉素减轻氧糖剥夺对SH-SY5Y细胞的损伤

目的:观察雷帕霉素(Rapa)对氧糖剥夺(OGD)的人神经母细胞瘤SH-SY5Y细胞的影响,并探讨自噬在其中的作用。方法:SH-SY5Y细胞随机分为4组:正常对照组(常规培养,不进行OGD处理)、Rapa组、OGD组(无糖培养基、1%O_2的三气培养箱内孵育细胞12 h)和Rapa+OGD组。进行形态学观察;MTT法检测细胞活力;乳酸脱氢酶(LDH)漏出率判断细胞损伤的程度;caspase-3活性检测试剂盒检测酶活性;原位末端标记(TUNEL)法检测凋亡水平;Western blot法检测凋亡相关蛋白Bax和Bcl-2、自噬标志蛋白LC3B-Ⅱ及自噬调控蛋白beclin-1的表达。结果:与OGD组相比,Rapa+OGD组的细胞存活率明显升高(P0.05),LDH漏出率及caspase-3酶活性明显降低(P0.05)。TUNEL染色观察结果显示,与OGD组相比,Rapa+OGD组的细胞凋亡明显减少(P0.05);Western blot实验结果显示Rapa+OGD组的Bcl-2、beclin-1及LC3B-Ⅱ蛋白的表达水平显著高于OGD组(P0.05),而Bax蛋白水平明显低于OGD组(P0.05)。结论:Rapa对OGD损伤的SH-SY5Y细胞具有保护作用,其机制可能与上调beclin-1蛋白、激活自噬有关。     

敲低STAT3基因可下调存活蛋白(survivin)水平促进U87MG胶质瘤细胞凋亡

目的探讨信号转导子与转录激活子3(STAT3)特异性小干扰RNA(siRNA)对U87MG胶质瘤细胞的促凋亡作用及其作用机制。方法体外培养U87MG胶质瘤细胞,利用MTT法观察si STAT3质粒对细胞增殖的影响,通过流式细胞术及吖啶橙染色观察其对细胞凋亡影响,反转录PCR和Western blot法检测下调STAT3对存活蛋白(survivin)的调控效应。结果 si STAT3质粒可明显抑制U87MG胶质瘤细胞增殖,敲低STAT3可明显促进胶质瘤细胞凋亡,下调STAT3水平可明显降低survivin mRNA和蛋白水平。结论敲低U87MG细胞STAT3可下调survivn水平、促进胶质瘤细胞凋亡。     

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.     

'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 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.     

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.