中国HIV感染长期不进展者CD4+CD25+Foxp3+调节性T细胞变化研究

目的 对中国HIV感染长期不进展者(LTNP)CD4+CD25+Foxp3+调节性T细胞水平及其与疾病进展相关性进行研究,探讨CD4+CD25+Foxp3+ 调节性T细胞在LTNP保护机制中发挥的作用.方法 选取74名HIV-1感染者(LTNP、典型进展HIV组、AIDS组)及16名健康对照,应用流式细胞仪胞内染色技术在单细胞水平检测CD4+CD25+Foxp3+调节性T细胞表达水平,分析其与CD4+ T细胞数量、病毒载量、淋巴细胞活化、凋亡水平的相关性.结果 中国HIV感染LTNP CD4+CD25+Foxp3+ T细胞百分率明显低于典型进展HIV、AIDS组及健康对照组(P<0.05).HIV/AIDS患者CD4+CD25+Foxp3+ T细胞百分率与CD4+ T细胞显著负相关(r=-0.509,P<0.001),与病毒载量明显正相关(r=0.414,P<0.01),与CD4、CD8+ T细胞表面CD38、CD95表达水平明显正相关(P<0.05),与CD4、CD8+ T细胞表面HLA-DR表达无显著相关性.结论 中国HIV感染LTNP CD4+CD25+Foxp3+ 调节性T细胞百分率明显低于典型进展者,提示调节性T细胞与LTNP保护机制相关.     

HIV感染者CD4~+T细胞TIGIT受体及其配体CD155表达情况研究

目的研究人类免疫缺陷病毒(human immunodeficiency virus,HIV)未治疗感染者CD4~+T细胞表面TIGIT受体及其配体CD155表达的情况。方法选取24例未经高效抗逆转录病毒治疗的HIV感染者和20例HIV抗体阴性健康对照(HIVnegative normal control,NC),用流式细胞仪检测受试对象外周血CD4~+T细胞表面TIGIT受体及其相关配体CD155的表达情况。结果未治疗HIV感染者CD4~+T细胞TIGIT受体表达百分数较健康人组表达明显增高(P0.000 1),并且与CD4~+T细胞绝对计数呈负相关(r=-0.444 1,P=0.029 7)。在未治疗HIV感染者中,CD4~+T细胞计数350/μl组CD4~+T细胞TIGIT表达百分数明显低于CD4~+T细胞计数≤350/μl组(P=0.029 2);病毒载量10~5/ml组CD4~+T细胞TIGIT表达百分数明显高于病毒载量≤10~5/ml组(P=0.015 5)。未治疗HIV感染者CD4~+T细胞表面CD155表达百分数与健康人组相比明显增高(P=0.004 2),且与病毒载量呈正相关(r=0.467 7,P=0.021 2),其中病毒载量10~5/ml组CD4~+T细胞CD155表达百分数明显高于病毒载量≤10~5/ml组(P0.000 1)。结论未治疗HIV感染者CD4~+T细胞TIGIT受体及其配体CD155表达百分数明显升高,且与CD+4绝对计数及病毒载量存在关联性,可为HIV患者的治疗和预后评估提供重要科学依据。     

无症状期HIV感染者CD4+和CD8+T细胞计数与病毒载量的关系

艾滋病是由人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染所导致的以免疫系统功能缺陷为特征的慢性高致死率传染病.CD4+T细胞是HIV损害的主要靶细胞,HIV可引起CD4+T淋巴细胞进行性丢失与功能受限[1-2].在HIV感染早期,CD8+T细胞增多并通过分泌各种细胞因子杀死被病毒感染的靶细胞,其高表达与病毒量载量呈正相关[3],而随着疾病进展,CD8+T细胞会消耗性减少.CD4+T细胞、CD8+T细胞计数与病毒载量的相关性一直为研究者关注[4-6].本研究检测了无症状期感染者,外周血CD4+T细胞和CD8+T细胞计数与病毒载量并分析它们的相关性.     

HIV感染者外周血CD4+ CD25+ Foxp3+/CD127low/-调节性T细胞表达水平对疾病进展的影响

目的:探讨HIV感染者外周血中CD4+ CD25+Foxp3+调节性T细胞(Treg)、CD4+ CD25+ CD127low/-Treg的水平及其与其他免疫指标的关系.方法:采集68例未经抗HIV治疗的HIV/AIDS患者(长期不进展组即LTNP组29例、典型进展的HIV感染组27例、AIDS组12例)及20例健康成人的外周抗凝全血,经免疫荧光染色,应用流式细胞仪分析CD4+T细胞、CD8+T细胞、NK细胞及CD4+CD25+Foxp3+/CD127low/-Treg的含量,并进行统计学分析.结果:除CD8+T细胞外,HIV/AIDS患者外周血中CD4+T细胞、NK细胞、CD4 +/CD8+结果均明显低于健康对照组(P＜0.05);随着疾病的进展,LTNP组、HIV组、AIDS组CD4+T细胞百分比、绝对值计数,CD8+T细胞绝对计数,NK细胞绝对计数,CD4 +/CD8+比值逐渐下降,而CD8+T细胞百分比逐渐上升.对CD4+ CD25+ Foxp3+ Treg与CD4+ CD25+CD127low/-Treg百分含量、绝对计数进行多重比较发现,各组间CD4+ CD25+ Foxp3+ Treg与CD4-CD25+ CD127low/-Treg所占CD4+T细胞百分含量的差异均有统计学意义(P＜0.05),并且随着疾病的发展,CD4+ CD25+ Foxp3+/CD127low/ Treg细胞百分含量逐渐上升,LTNP组与健康对照组之间、HIV组和AIDS组之间CD4+ CD25+Foxp3+/CD127low/ Treg绝对计数差异无统计学意义(P＞0.05),其余各组间的差异均有统计学意义(P＜0.05),并且随着疾病的发展,CD4+ CD25+ Foxp3-/CD127low/-Treg绝对计数逐渐下降.结论:CD4+ CD25+ Foxp3 +/CD127low/-Treg在HIV持续感染的免疫发病机制中有一定作用.     

外周血纯真、记忆性CD8~+T细胞数量与中国HIV/AIDS患者疾病进程的相关性研究

目的:研究不同疾病进展阶段的中国HIV/AIDS患者外周血CD8+T细胞亚群的数量变化,以探讨各亚群与HIV感染疾病进展的相关性。方法:首先应用多参数(CD45RA、CCR7、CD28)流式细胞术圈定幼稚(nave)CD8+T细胞和记忆性(memory)CD8+T细胞(包括TCM、TEM-1及TEM-2),随后测定58例不同疾病进展阶段HIV/AIDS患者和20例健康对照者外周血各CD8+T细胞亚群的绝对数量和占CD8+T细胞的百分比,分析其与病毒载量、CD4+T细胞数量的相关性。结果:HIV/AIDS患者与健康对照相比,nave CD8+T细胞百分比和绝对值均显著减少,memory CD8+T细胞百分比和绝对值均显著升高(P0.05)。在memoryCD8+T细胞各亚群中,效应型(effector memory T cells,TEM)-1百分比显著升高(P0.05)。HIV感染缓慢进展(slow progressor,SP)组、HIV组及AIDS组中,nave CD8+T细胞百分比和绝对值均依次下降,AIDS组、HIV组显著低于SP组(P0.05),memory CD8+T细胞绝对值依次下降,各组间的下降均有显著性差异(P0.05)。在memory CD8+T细胞各亚群中,TEM-1百分比依次升高,AIDS组显著高于SP组(P0.05);TEM-2百分比及绝对值依次下降,AIDS组显著低于SP组(P0.05)。相关性分析发现,nave CD8+T细胞与CD4+T细胞显著正相关(P0.01),与HIV病毒载量显著负相关(P0.01);中央型(central memory T cells,TCM)和TEM-2型memory CD8+T细胞与CD4+T细胞显著正相关(P0.01)。结论:Nave、memory CD8+T细胞数量与HIV疾病进展显著相关。     

中国HIV感染长期不进展者T细胞表面IL-7受体表达研究

目的:了解中国HIV感染长期不进展者(Long-Term Non-Progressor,LTNP)T细胞表面IL-7(Interleukin-7,IL-7)受体的表达,分析其与疾病进展的关系。方法:收集LTNP组、HIV组、AIDS组及健康对照组(每组各20例)的抗凝全血,用流式细胞仪检测IL-7受体的表达,并分析IL-7受体表达与血浆中IL-7水平的相关性。结果:LTNP组CD4+T、CD8+T、中枢记忆T细胞(Central memory T cells,Tcm)、效应记忆性T细胞(Effector memory T cells,Tem)表面IL-7受体表达水平明显高于无症状HIV感染组(HIV组)、AIDS病人组(AIDS组)(P<0.05),LTNP组初始T细胞(Na ve T cells,Na ve)、终末分化效应记忆型T细胞(Terminallydifferentiated effector memory T cells,Tem/td)表面IL-7受体表达水平与HIV组、AIDS组间差异无统计学意义。HIV/AIDS患者IL-7受体在CD4+T和CD8+T细胞上表达的百分率与血浆IL-7水平呈明显负相关(P<0.05),与CD4+T细胞数量呈明显的正相关(P<0.05),与病毒载量呈明显负相关(P<0.05)。结论:外周血T细胞表面IL-7受体表达与HIV疾病进展密切相关,LTNP组T细胞保持较高水平的IL-7受体表达,可能是保护因素之一。     

慢性乙型肝炎病毒感染者CD8~+T细胞Toll样受体2表达增强

目的测定未经抗病毒治疗的慢性乙型肝炎病毒(HBV)感染者CD8~+T细胞中Toll样受体2(TLR2)的水平,探索TLR2在慢性HBV感染者CD8~+T细胞中的表达的情况。方法采用实时荧光定量PCR检测40例样本的血清HBV载量,分为高病毒载量组(HBV DNA1×104拷贝/m L)、低病毒载量组(HBV DNA1×104拷贝/m L),19例志愿者作为健康对照组;分离外周血单个核细胞,流式细胞术检测CD8~+T淋巴细胞亚群中TLR2和CD38、HLA-DR、CD95、程序性死亡蛋白1(PD-1)的表达,并分析TLR2表达情况及与它们之间的相关性。结果低病毒载量组与高病毒载量组CD8~+T细胞TLR2的表达较健康对照组高,低病毒载量组CD8~+T细胞TLR2表达高于高病毒载量组;相关性分析结果显示CD8~+T细胞亚群中TLR2和CD38、HLA-DR、CD95、PD-1表达缺乏相关性。结论 HBV感染者CD8~+T淋巴细胞TLR2的表达增强。     

HIV-1感染疾病缓慢进展者CD8+T淋巴细胞非细胞毒性免疫应答作用的研究

目的 探讨HIV-1感染疾病缓慢进展者CD8+T淋巴细胞非细胞毒性抗病毒应答功能(CNAR)的变化.方法 应用密度梯度离心法、免疫磁珠法纯化健康人CD4+T淋巴细胞和HIV感染者CD8+T淋巴细胞,用HIV毒株SF-33感染健康人CD4+T淋巴细胞,并加入不同疾病进程HIV感染者CD8+T淋巴细胞共培养,收集培养上清,应用ELISA方法测定上清中HIV-1 p24含量.结果 我们研究发现缓慢进展组(slow progressors,SP)、HIV典型进展组(typical progressors,TP)、健康对照组及AIDS组中CNAR功能依次下降(89%>77%>73%>61%),各组间的下降差异均有统计学意义(P<0.05);在HIV感染者中,CNAR功能与CD4+T细胞绝对计数呈显著正相关;与病毒载量无显著相关性.结论 CNAR功能对HIV感染疾病不进展可能具有保护作用.     

免疫调控受体PD-1和TIGIT在HIV感染者/HIV患者CD3~+CD4~-T细胞表达研究

深入了解免疫调控受体程序性死亡分子1(programmed death 1,PD-1)和T细胞免疫球蛋白及免疫酪氨酸样抑制基序(T cell immunoglobulin and ITIM domain,TIGIT)在人类免疫缺陷病毒(human immunodeficiency virus,HIV)感染者/HIV患者外周血CD3~+CD4~-T细胞的表达情况及其与疾病进展的关系。用流式细胞仪检测24例未治疗的HIV感染者/HIV患者外周血CD3~+CD4~-T细胞表面PD-1和TIGIT的表达百分比、CD4+T细胞绝对值计数,实时荧光定量PCR检测HIV病毒载量,并与20例HIV抗体阴性者表达情况比较(HIV-negative normal control,NC)。结果发现HIV感染者/HIV患者CD3~+CD4~-T细胞表面TIGIT受体表达百分数较健康对照组明显增高(P0.000 1),与CD4+T细胞绝对计数呈负相关(r=-0.450 4,P=0.027 1),与病毒载量呈正相关(r=0.621 4,P=0.001 2);HIV感染者CD3~+CD4~-T细胞PD-1受体表达百分数较健康对照组明显增高(P0.000 1),与CD4+T细胞绝对计数呈负相关(r=-0.455,P=0.0255);PD-1和TIGIT共表达的CD3~+CD4~-T细胞百分数在HIV感染者/HIV患者中表达明显增高(P0.000 1)。HIV感染机体后,CD3~+CD4~-T细胞PD-1受体和TIGIT受体表达百分数均明显增高,且与HIV疾病进展密切相关。     

病毒载量和T淋巴细胞计数在HIV感染者临床治疗疗效观察中的应用

目的 研究病毒载量检测和CD4^ 计数在评价人类免疫缺陷病毒(HIV)感染者疗效中的应用效果。方法 对HIV感染者临床病例73例进行了实验室和临床观察，其中包括6例鸡尾酒治疗病例、36例中药试验性治疗病例及31例未进行治疗的感染者。主要实验室指标包括血浆病毒载量及T淋巴细胞亚群计数。结果 在进行治疗后3个月时联合治疗组的病毒载量明显低于其他两组，并且在其后保持在很低的水平，CD4^ 计数水平明显高于其他两组并在其后持续升高。在整个观察期间，中药治疗组的病毒载量检测和CD4^ 计数水平与未治疗组差异无显著性，但在临床症状观察中中药治疗组较未治疗组有明显改善。结论 病毒载量检测和CD4^ 计数试验是评价抗HIV治疗疗效的有效方法。     

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.