脑死亡对巴马小型猪心脏结构与功能的影响及其机制的实验研究

目的： 探讨脑死亡状态对巴马小型猪心脏结构与功能的影响及蛋白激酶C (PKC)在其发生机制中的作用。方法: 巴马小型猪10只，随机分为脑死亡组与对照组，每组5只。应用改进的缓慢间断颅内加压法建立脑死亡模型，对照组仅开颅麻醉维持。于脑死亡后6、12和24 h检测血清中肌钙蛋白Ｔ(cTnT)、IL-1β、IL-6及TNF-α水平，24 h开胸取心肌组织，HE染色观察心脏组织结构变化，电镜观察心脏超微结构变化，免疫组化染色观察PKC-α蛋白表达，RT-PCR法检测PKC-α mRNA表达。结果: （1）心肌组织学变化：脑死亡后24 h可见心肌结构改变，光镜下见心内膜下片状出血，心肌溶解，断裂；电镜下见线粒体水肿，肌纤维模糊融合，嵴部分消失，膜部分融合。（2）血清cTnT变化：脑死亡组血清cTnT自脑死亡后6 h开始升高，并随时间延长而逐渐升高；各时点两组相比脑死亡组明显高于对照组（P<0.05）。（3）炎症介质变化：脑死亡组IL-1β、IL-6、TNF-α水平自6 h开始升高，并随时间延长而逐渐升高；各时点两组相比脑死亡组明显高于对照组（P<0.05）。（4）心肌细胞中PKC-α mRNA及其蛋白水平的变化：脑死亡组PKC-α mRNA及其蛋白表达水平均明显高于对照组（P<0.05）。结论: 脑死亡导致巴马小型猪心脏结构与功能的损伤，炎症介质水平升高；脑死亡时心脏PKC-α 表达水平升高。PKC-α的活化可能参与了脑死亡状态下心脏的损伤过程。     

浅低温体外循环围术期血清炎症介质的变化

目的 探讨浅低温体外循环围术期炎症介质的释放规律。方法 按入选标准筛选先天性心脏病患者24例，均采用浅低温体外循环心脏直视术，用酶联免疫吸附法测定患者术前（T1）、CPB30min（T2）、CPB结束后2h（T3）、12h（T4）、24h（T5）各时间点血清IL-6、IL-8、IL-10的浓度。结果 所有患者血清IL-6、IL-8、IL-10浓度在CPB开始后均升高（P〈0，01），于术后2h（T3）逐渐达高峰，术后12h（T4）逐渐下降，术后24h（T5）虽仍高于术前（T1）水平，但较高峰时（T3）已明显下降。结论 浅低温CPB术后患者血清IL-6、IL-8、IL-10浓度逐渐升高．术后2h达高峰．并于24h内恢复接近正常水平。     

肾上腺素对内毒素致大鼠炎症性肝损害的保护作用

目的 探讨肾上腺素（Epi）对内毒素（脂多糖，LPS）致大鼠炎症性肝损害的保护作用及其作用机制。方法 50只SD大鼠随机分为5组（每组各10只）：对照组：静脉滴注生理盐水2．4mL·kg^-1·h^-1；LPS组：静脉注射LPS6mg·kg^-1后，静脉滴注生理盐水2．4mL·kg^-1·h^-1；低、中和高剂量Epi组：静脉注射LPS6mg·kg^-1后，分别静脉滴注Epi0．12、0．3和0．6μg·kg^-1·min^-1。在LPS注射前、注射后2和6h3个时点取血，检测血清ALT、AST、TNF-α、IL-1β和IL-10水平，并在6h时点观察肝脏的组织病理学改变。结果 LPS组注射LPS后2、6h血清AST和ALT水平较对照组显著升高。同时血清TNF-α、IL-1β和IL-10水平亦较对照组显著升高（P〈0．05）。病理检查结果示：LPS组肝窦扩张、充血，局灶性肝细胞坏死。高剂量Epi可显著降低血清AST和ALT水平，减轻肝脏病理损伤，并显著可降低TNF-α水平和升高IL-10水平（1）8LPS组，P均〈0．05），但对IL-1β水平无影响。中、低剂量Epi对LPS致炎症性肝损害无明显保护作用。结论 Epi可通过抗炎作用减轻LPS诱导的炎症性肝损害。     

猪脑死亡模型建立及建立过程中血压、心率变化

目的采用改进的缓慢间断颅内加压法建立猪脑死亡模型，观察建立过程中血压、心率变化。方法长白猪12头，随机分为对照组（C组）和脑死亡组（B组），每组6头。C组维持麻醉24h，仅行开颅术并颅内放置Foley气囊导管，不建立脑死亡模型；B组应用改进的缓慢间断颅内加压法建立脑死亡模型，通过呼吸、循环支持维持猪脑死亡状态24h。监测2组动物在实验过程中平均动脉压（mean artery pressure，MAP）、心率（heart rate，HR）变化。结果B组6头猪均成功建立脑死亡模型。经Foley气囊导管缓慢间断颅内加压后，B组动物血压、心率缓慢下降后骤然升高，呼吸频率减慢、呼吸幅度加深，平均峰值动脉压和平均峰值心率与颅内加压前MAP、HR比较，差异有统计学意义；脑死亡后6、12和24h，B组猪MAP和HR与C组比较，差异有统计学意义。结论应用改进的缓慢间断颅内加压法可成功制作猪脑死亡模型，经有效的呼吸和循环支持，能稳定地维持猪脑死亡状态24h，为进一步研究脑死亡状态下猪肝脏形态和功能变化提供了坚实基础。     

对脂多糖攻击小鼠血及肝IL-6和TNF-α含量的影响

目的：研究重组人白细胞介素-10（rhIL-10）对脂多糖（LPS）诱导的血、肝IL-6和TNF-α炎症介质含量变化的影响。 方法： 小鼠腹腔注射LPS建立炎症模型，并同时静脉注射不同剂量的rhIL-10，ELISA法测定12 h、24 h、48 h和72 h肝组织和血清IL-6和TNF-α的含量。 结果： 注射rhIL-10后12 h，肝组织和血清IL-6、TNF-α水平开始下调，24-48 h抑制作用最明显（P＜0.05），72 h后抑制作用减弱，且呈剂量效应关系。 结论： 利用基因工程技术制备的重组人白细胞介素10（rhIL-10）显著下调肝组织和血清IL-6和TNF-α的水平。     

实验性巴马小型猪脑死亡判定标准的初步探索

脑死亡作为移植物延迟性功能恢复和慢性失功的潜在影响因素,对移植器官的损伤有待于深入研究。这就要求建立稳定的脑死亡实验模型,并制定客观性强、简便易行的脑死亡判定标准。本实验拟利用巴马小型猪的脑死亡模型,初步探讨动物实验脑死亡的判定标准。1材料与方法1.1实验动物和分组:第三军医大学实验动物中心提供的健康巴马小型猪31头,随机分为:脑死亡组(B组,n=26),建立脑死亡模型并维持24h;对照组(C组,n=5),持续麻醉维持24h,不建立脑死亡模型。1.2脑死亡模型的建立和维持:经缓慢间断颅内加压法建立巴马小型猪脑死亡模型[1],多道生理记录仪…     

高血压对急性心肌梗死患者血清IL-1β、IL-6及IL-8水平的影响

为探讨高血压对急性心肌梗死（AMI）患者血清白介素-1β（IL-1β）、白介素-6（IL-6）及白介素-8（IL-8）的影响。AMI患者67例,根据高血压病史分为非高血压组37例,高血压组30例,对照组28名,采用ELISA测定各组患者入院第24h、第14d及对照组的血清IL-1β、IL-6及IL-8水平。结果表明非高血压组患者的炎性因子水平于AMI发病第24h显著高于对照组（P〈0．001）,发病第14天炎症因子水平与对照组相比无显著性差异,高血压组患者AMI发病第24h、第14d血清炎症因子水平均显著高于非高血压组和对照组（P〈0．001）。结果显示,IL-1β、IL-6及IL-8参与了AMI的发病,但高血压对炎性因子的升高起到了关键作用。     

钩藤碱降低内毒素血症小鼠死亡率的机制研究

目的： 观察钩藤碱对内毒素血症小鼠死亡率及器宫损伤的影响，并探讨其作用机制。方法: 雄性小鼠随机分为对照组、脂多糖（LPS）组、钩藤碱（Rhy）防治组和Rhy对照组，分别予以生理盐水、Rhy皮下注射，1 time/d，连续3 d，第3 d皮下注射后1 h，腹腔注射生理盐水或LPS（20 mg/kg）。观察各组小鼠的死亡率，肺、小肠组织病理改变；测定注射LPS后12 h各组肺湿/干重比值 (W/D)及血清丙氨酸氨基转移酶（ALT）、门冬氨酸氨基转移酶（AST）、尿素氮（BUN）和肌酐（Cr）的水平；用酶联免疫吸附法（ELISA）测定血清肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）及白细胞介素-10（IL-10）的含量，用硝酸还原酶法试剂盒测定血清一氧化氮（NO）的含量。进一步复制盲肠结扎穿孔的脓毒症模型， 观察钩藤碱对脓毒症小鼠生存率的影响。结果: LPS攻击后24 h小鼠的生存率明显低于对照组，8、16 mg/kg的钩藤碱防治组小鼠生存率高于LPS组。但钩藤碱并不能降低CLP小鼠的死亡率，而且，8 mg/kg钩藤碱治疗组小鼠的死亡率反而高于CLP小鼠的死亡率。LPS攻击后12 h病理检查发现LPS组小鼠肺及小肠组织均有严重的炎症表现；肺W/D、血清ALT、AST、BUN、Cr水平显著高于对照组；LPS攻击后2 h血清TNF-α、IL-1β及IL-10含量及8 h血清NO水平显著高于对照组。LPS攻击后12 h， Rhy防治组肺及小肠组织损伤无明显改善；肺W/D、血清ALT、AST、BUN、Cr水平与LPS组比较无显著差异；LPS攻击后2 h血清TNF-α水平显著低于LPS组，但2 h血清IL-1β及IL-10含量及8 h血清NO水平与LPS组比较无显著差异。结论: 钩藤碱能降低内毒素血症小鼠的死亡率，但不能降低脓毒症小鼠的死亡率，抑制TNF-α的生成可能是钩藤碱降低内毒素血症小鼠死亡率的机制之一。     

早期胰岛素泵注对脓毒症大鼠肝损害的影响

目的探讨早期胰岛素泵注对脂多糖（LPS）致大鼠脓毒症模型肝损害的保护作用。方法24只SD大鼠随机分为LPS＋生理盐水组、LPS＋胰岛素组和生理盐水对照组,各组均为8只。各组大鼠在实验前1d行右颈外静脉置管术。LPS＋生理盐水组腹腔注射LPS10mg·kg^-1,同时持续静脉泵注生理盐水1mL·h^-1;LPS＋胰岛素组腹腔注射LPS10mg·kg^-1,同时持续静脉泵注胰岛素生理盐水溶液1mL·h^-1（胰岛素用量为0．25U·kg^-1·h^-1）。生理盐水对照组腹腔注射生理盐水10mg·kg^-1,同时持续静脉泵注生理盐水1mL·h^-1。测定各组腹腔注射LPS或生理盐水前和注射后2、6、12、24h的血糖水平,检测各组腹腔注射LPS或生理盐水后2、6h的血清TNF-α、IL-6水平及24h的血清ALT和AST水平,并观察各组腹腔注射LPS或生理盐水后24h的肝脏组织病理学改变。结果LPS＋生理盐水组在腹腔注射LPS后各采样时间点,血糖水平较生理盐水对照组均显著升高（P〈0．05）。注射LPS或生理盐水后2和6h,LPS＋生理盐水组血清TNF-α和IL-6水平显著高于生理盐水对照组（P〈0．05）。注射LPS或生理盐水后24h,LPS＋生理盐水组血清ALT和AST水平均较生理盐水对照组显著升高（P〈0．05）。LPS＋胰岛素组注射LPS后各采样时间点血糖、TNF-α、IL-6、ALT及AST水平均显著低于LPS＋生理盐水组（P〈0．05）,LPS＋生理盐水组肝脏病理学检查示局灶性肝细胞坏死,炎性细胞浸润,小叶间静脉充血扩张;LPS＋胰岛素组肝脏病理学改变较LPS＋生理盐水组明显减轻。结论早期胰岛素静脉泵注可通过抗炎和降低应激性高血糖作用减轻LPS诱导的肝损害。     

β-榄香烯对CLP诱导的脓毒症大鼠肝损伤的保护作用

目的：探讨β-榄香烯在盲肠结扎穿孔（CLP）诱导的脓毒症大鼠肝功能和炎症损伤中的保护作用。方法：50只Wistar大鼠分为健康对照组、模型组、模型+β-榄香烯25 mg/kg组、模型+β-榄香烯50 mg/kg组、模型+β-榄香烯100 mg/kg组。ELISA测定各组大鼠血清中天冬氨酸氨基转移酶（AST）、谷氨酸氨基转移酶（ALT）、高密度脂蛋白（HDL）、低密度脂蛋白（LDL）、三酰甘油（TG）水平;HE染色观察肝脏病理损伤;Western blot检测肝组织中cleaved cas9、cleaved cas3蛋白表达水平,ELISA检测血清和肝组织中iNOS和IL-10含量,Western blot和免疫组化检测NF-κB P65蛋白表达水平。结果：与健康对照组相比,模型组大鼠血清中AST、ALT、LDL、TG水平升高,HDL水平降低（P<0.05）,肝脏病理损伤严重,cleaved cas9、cleaved cas3蛋白表达水平升高,血清和肝组织中iNOS和IL-10含量增多,p-P65/P65水平升高（P<0.05）。与模型组相比,25 mg/kg β-榄香烯给药...     

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.