齿龈内阿米巴与口腔毛滴虫的研究进展

齿龈阿米巴（Entamoeba gingivalis）与口腔毛滴虫（Trichomonas tenax）是寄居人体口腔龈沟、龋齿和牙垢内的原虫。越来越多的流行病学调查及动物实验都间接或直接的证明了两种原虫与口腔疾病的密切关系。本文重点综述两种口腔原虫的形态学观察、人群中感染情况、致病机制、病原诊断方法和防治措施方面的研究进展，以期推动研究的进一步深入，为口腔疾病的治疗带来新的曙光。     

根除儿童口腔幽门螺杆菌预防胃内幽门螺杆菌感染的多中心研究

目的:探讨根除儿童口腔幽门螺杆菌（Hp）预防胃内Hp感染的可能性。方法:采用多中心前瞻随机研究，选取口腔Hp阳性但胃内Hp阴性的幼儿园儿童共计427例，随机分为使用“无幽梅”牙膏组与普通牙膏组，分别接受“无幽梅”牙膏和普通牙膏。疗程结束后，再次检测口腔Hp，将口腔Hp阳性及阴性患者各分为一组，1年后行C13呼气试验检查，分析两组患者胃内Hp感染情况。口腔Hp检测方法采用特异度及敏感度双高的套式PCR方法。结果:随访1年，口腔Hp阴性组胃内Hp感染率为0.51%，口腔Hp阳性组胃内Hp感染率为6.51%，两组统计差异具有显著性（P<0.01）。结论:儿童根除口腔Hp可以降低胃内Hp感染的发生。     

广东和云南部分地区艾滋病患者中隐孢子虫感染的调查分析

目的 了解艾滋病患者中隐孢子虫的感染状况.方法 收集广东和云南省部分地区艾滋病患者的粪便,采用改良的抗酸染色法和免疫荧光染色法检测隐孢子虫卵囊;并同时检测患者的CD4细胞计数.结果 212例艾滋病患者粪便标本中9例标本为阳性,感染率为4.25%.广东和云南的艾滋病患者隐孢子虫感染率分别为4.00%(5/126)和4.65%(4/86),两地之间差异无统计学意义(P＞0.05);稀便与软便中的隐孢子虫卵囊检出率分别为12.00%(3/25)和3.21%(6/187),其差异无统计学意义(校正χ2=2.31,P＞0.05);男性与女性艾滋病患者隐孢子虫感染率分别为5.07%(7/138)和2.70%(2/74),其差异无统计学意义(校正χ2=0.21,P＞0.05);50～59岁组隐孢子虫感染率高于30～39岁组的感染率(校正χ2=7.15,P＜0.01);接受抗病毒治疗组与未接受治疗组艾滋病患者隐孢子虫感染率分别为1.12%(2/179)和21.21%(7/33),两者差异有统计学意义(校正χ2=18.54,P=0.0000);艾滋病晚期,尤其是CD4细胞计数少于100个/μl的患者其发病率明显提高.结论 我国南方艾滋病患者中存在着隐孢子虫感染,但发病率明显低于国外报道;艾滋病患者的便形、性别及所处地区不能预示隐孢子虫感染率;抗病毒治疗能降低隐孢子虫病感染率,艾滋病患者的隐孢子虫感染多发生在疾病的终末期.     

富顺县某村级小学学生肠道线虫感染状况调查分析

目的 了解农村儿童肠道蠕虫感染状况,为制定防治措施提供依据.方法 采用加藤厚涂片(Kato)法对农村小学校学生粪便检查蠕虫卵,掌握其感染状况,并进行描述性分析.结果 共查河湾村小学生341名,查出蛔虫、钩虫、鞭虫三种肠道寄生虫,总阳性率48.09%;三种寄生虫感染男女间无显著性差异,三年级学生感染率(58.27%)明显高于一年级学生的感染率(35.05%),χ2=12.336,P<0.01;留守儿童感染率(56.99%)明显高于非留守儿童(37.42%),χ2=12.951,P<0.01.结论 肠道蠕虫防治工作的重点应放到农村村级小学,要特别重视留守儿童的肠道寄生虫防治.     

重庆市城市与农村儿童蛲虫感染流行特征分析

目的了解重庆市城市与农村地区儿童的蛲虫流行特征。方法选择重庆市城区和农村各1个区县作为调查点,每个调查点按东、西、南、北、中抽取1个乡镇（街道）,每个乡镇（街道）抽取150名3～12岁儿童,每个点750名以上。采用圆底试管透明胶纸肛拭法,定性检查蛲虫卵。分析比较城市和农村地区儿童蛲虫感染率差异。结果重庆市儿童蛲虫感染率为6.85%,城市（2.14%）低于农村地区（12.13%）（χ2=62.14,P〈0.01）。城市及农村儿童的性别间比较,蛲虫感染率差异无统计学意义（χ2城市=0.21,χ2农村=1.32,P均〉0.05）;同一性别间,城市与农村间比较,差异均有统计学意义（P均〈0.01）。城市、农村不同年龄组间儿童感染率比较差异有统计学意义（χ2城市=12.65,χ2农村=34.22,P均〈0.01）;在同一年龄组间比较,除11～岁组外,其他年龄组间比较,差异均有统计学意义（P均〈0.01）。城市各个年龄段儿童蛲虫感染率变动不大（χ2趋势=0.89,P〉0.05）;农村儿童感染率趋势随年龄的增加而降低（χ2趋势=3.36,P〈0.01）。结论重庆市城市与农村儿童蛲虫感染具有不同特征,应针对不同地区、不同人群采取适宜的防治措施。     

胆囊良恶性病变组织中HMGA2和CD9表达及意义

目的 研究胆囊良恶性病变组织中HMGA2和CD9表达水平及其临床病理意义.方法 108例胆囊腺癌、46例癌旁组织、15例腺瘤和35例慢性胆囊炎手术切除标本常规制作石蜡包埋切片, HMGA2和CD9染色方法为EnVision免疫组化法.结果 胆囊腺癌HMGA2表达阳性率明显高于癌旁组织(χ2=16.13,P<0.01)、腺瘤性息肉(χ2=8.19,P<0.01)和慢性胆囊炎(χ2=21.41,P<0.01); 胆囊腺癌CD9表达阳性率明显低于癌旁组织(χ2=8.76,P<0.01)、腺瘤性息肉(χ2=3.96,P<0.05)和慢性胆囊炎(χ2=14.31,P<0.01);HMGA2表达阳性和(或)CD9表达阴性的良性病例的胆囊上皮均呈中至重度不典型增生.高分化、肿块最大径<2 cm、无淋巴结转移、未侵犯周围组织的病例HMGA2表达阳性率明显低于低分化、肿块最大径≥2 cm、淋巴结转移和侵犯周围组织的病例(P<0.05或P<0.01);高分化腺癌、肿块最大径<2 cm、无淋巴结转移和未侵犯周围组织的病例CD9表达阳性率明显高于低分化腺癌、肿块最大径≥2 cm、淋巴结转移和侵犯周围组织病例(P<0.05或P<0.01).经Kaplan-Meier生存分析发现HMGA2表达阳性病例术后生存期明显低于阴性表达病例(P=0.020),但CD9表达阳性病例术后生存期明显高于阴性表达病例(P=0.019);Cox多变量回归分析显示HMGA2阳性表达和(或)CD9表达阴性是反映胆囊腺癌预后不良的一个重要指标.结论 HMGA2和CD9表达与胆囊腺癌发生、临床生物学行为及预后有密切关系.     

生物活性玻璃抑制酸蚀后不同时间牙釉质的刷牙磨损

背景：生物活性玻璃具有良好的生物相容性,并具有优异的促进牙齿再矿化和抗酸蚀效果。 目的：比较生物活性玻璃牙膏和含氟牙膏对牙釉质酸蚀后不同时间点刷牙磨损的影响。 方法：制备56个牛牙釉质片,树脂包埋并暴露大小约6 mm×6 mm的釉质平面,表面制备沟槽并充填银汞合金,磨平抛光后随机均分为7组,模拟酸性饮食后刷牙的过程,其中6组分别用普通牙膏、含氟牙膏、生物活性玻璃牙膏在雪碧酸蚀后即刻和酸蚀后30 min两个时间点以牙刷磨刷,另1组不酸蚀,只用普通牙膏磨刷,为无酸蚀对照组,过程循环60次。以银汞合金为参照,用激光共聚焦显微镜观察各组样本磨刷后的表面磨损量。 结果与结论：酸蚀后刷牙各组磨损量明显高于无酸蚀对照组(P < 0.05)。在酸蚀后同一时间刷牙条件下,生物活性玻璃牙膏组磨损量均低于含氟牙膏组(P < 0.05);使用同种牙膏条件下,牙齿酸蚀后唾液浸泡30 min后刷牙组的磨损量均低于酸蚀后即刻组(P < 0.05)。说明应用生物活性玻璃牙膏在酸性饮食30 min后刷牙,可有效减少刷牙对酸蚀牙釉质的磨损。  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     

单双相抑郁障碍住院患者临床特点比较

目的探讨双相抑郁和复发性抑郁住院患者的临床特征及相关因素。方法回顾性分析1999年到2001年我院诊断情感障碍住院病人506例,比较双相抑郁107例和复发性抑郁399例人口学资料、病程、诊断及疗效等变量。结果复发性抑郁组女性比例高于双相抑郁组(268/399比54/107,χ2=10.17,P<0.01);复发性抑郁组以往多次抑郁发作史低于双相抑郁组(41.4%/57%,χ2=8.4,P<0.01),病程短于双相抑郁组(58.8±4.5/96.3±9.6,t=-3.77,P<0.01),首次抑郁年龄大于双相抑郁组(41.7±0.8/29.4±1.4,t=6.95,P<0.01),首次抗抑郁治疗有效率大于双相抑郁组(81.3%/57%,χ2=95.2,P<0.01),复发抑郁组同一次病程首次诊断符合率高于双相抑郁组(97%/31.8%,χ2=324.4,P<0.01),双相抑郁组中61.7%(66/107)首次诊断为抑郁起病年龄20岁左右者发生双相抑郁概率明显大于60岁以后起病者(OR=2.45)。病程5年以上发生双相抑郁概率大于病程短于1年者(OR=2.75),首次抗抑郁疗效差出现双相抑郁概率大于首次抗抑郁疗效好者(OR=3.18)。双相抑郁组同一次病程61.7%首次诊断抑郁障碍。结论首发抑郁的年龄、病程、首次抗抑郁效果与出现双相抑郁的概率有关。首发抑郁年龄越早,病程越长,首次抗抑郁疗效越差,发生双相抑郁概率越大。2/3双相抑郁首次诊断复发性抑郁。     

子宫颈鳞状细胞癌中MCM5和p16~(INK4A)的表达及其意义

目的探讨HPV 16感染的子宫颈癌中MCM5与p16~(INK4A)表达及其意义。方法采用RT-PCR及免疫组化SABC法检测HPV 16感染正常子宫颈、子宫颈上皮内病变(cervical intraepithelial neoplasia,CIN)包括CIN 1与CIN 2~3及子宫颈鳞状细胞癌中MCM5、p16~(INK4A)的mRNA及蛋白表达,并分析其临床意义。结果 MCM5、p16~(INK4A)mRNA在子宫颈癌组织中表达均明显高于正常组织(χ~2=-6.589,P0.001;χ~2=-4.349,P0.001);且随子宫颈病变程度的升高逐渐增加,差异有显著性(χ~2=57.141,P0.001;χ~2=47.628,P0.01);子宫颈癌中MCM5 mRNA的表达与临床分期、病理分级有关,Ⅰa~Ⅰb期明显低于Ⅱa~Ⅱb期(χ~2=-4.93,P0.01),其表达随病理分级降低而降低(χ~2=-4.017,P0.01);子宫颈癌中p16~(INK4A)mRNA表达随病理分级的降低而降低(χ~2=8.560,P0.01);MCM5、p16~(INK4A)mRNA在子宫颈鳞状细胞癌中表达最明显;MCM5和p16~(INK4A)蛋白表达呈正相关(r=0.497)。结论子宫颈癌中MCM5和p16~(INK4A)高表达,MCM5可较好的反应子宫颈的恶性增生,与p16~(INK4A)联合检测对完善CIN分级及预后的判断意义重大。     

心理干预对抑郁症患者复发因素的影响

目的探讨心理干预对抑郁症患者复发因素的影响。方法将85例抑郁症患者随机分为干预组(药物 心理干预)及对照组(单纯药物治疗),分别于入组前及1年后进行SDS、HAMD、MMPI、P300电位测定。结果心理干预后干预组SDS(35.4±5.3)、HAMD(17.5±3.1)量表分明显低于对照组(41.7±6.1,F=4.1,21.1±5.5,F=4.2,P<0.05);干预组MMPI中F、Hs、D、Hy、Pd、Pt、Ma量表分明显低于对照组(F=3.9-7.7,P<0.01或P<0.05);干预组P300电位中N2、P3潜伏期较对照组明显缩短、P3波幅较对照组明显升高(P<0.01或P<0.05);干预后干预组的再次复发率(17.8%)明显低于对照组(47.5%,χ2=14.38,P<0.01)。结论心理干预配合药物治疗对抑郁症患者的情绪、人格及认知等复发因素具有积极的意义。     

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.