Hirano bodies and related neuronal inclusions

Hirano bodies are bright eosinophilic intracytoplasmic inclusions which have a highly characteristic crystalloid fine structure. They occur preferentially in the neuronal processes of the CA1 area in Amnion's horn in a wide variety of conditions, especially amyotrophic lateral sclerosis and parkinsonism–dementia complex on Guam, Alzheimer's disease, Pick's disease and 'normal' elderly individuals. Hirano bodies contain epitopes of actin, actin–associated proteins, tau, middle molecular weight neurofilaments subunit and a C–terminal fragment of β-amyloid precursor protein. In addition to the CA1 area of Amnion's horn, they have also been identified in many other areas of the nervous system in humans and various experimental animals. Although usually observed in neurons. Hirano bodies may also be present in other cell types. It is the consensus that Hirano bodies in the pyramidal layer of CA1 originate largely from an age-related alteration of the microfilamentous system.     

体外膜肺对犬肺泡Ⅱ型上皮细胞系统超微结构的影响

目的：观察体外膜肺(ECMO)早期肺泡Ⅱ型上皮细胞(ATⅡ)及肺表面活性物质(PS)系统超微结构改变，探讨ECMO过程中ATⅡ功能变化，不断改良ECMO技术。方法：应用电子显微镜观察体外膜肺犬ATⅡ及PS系统超微结构。结果：ECMO组均可见PS层丧失连续、均匀绒状结构，脱落人肺泡腔或聚集成块现象或散落于肺泡腔内；可见ATⅡ板层小体减少、空泡形成，核变性、崩解；基底膜水肿、裸露，甚至断裂，炎性细胞渗出到肺泡腔。与对照组比较有显著差异，提示现有的ECMO治疗6h可引起肺泡Ⅱ型上皮细胞系统超微结构的改变。结论：现有的ECMO技术还有待改良。     

Anisotropic crystalline microstructures in dendritic arborizations of dried mid-cycle cervical mucus: surface morphology and crystallographic study.

Studies using scanning electron microscopic techniques permitted characterization of the nature and structure of the anisotropic elements present in dried preparations of mid-cycle cervical mucus. Sodium and potassium sulphates were located in the dehydrated matrix either isolated or bound to the dendrites. Depending on crystallization conditions, they appeared as well-formed individual crystals or as spherulites.     

正常大肠,癌旁粘膜及癌表面扫描电镜观察

本文应用扫描电子显微镜并结合组织学检查,对20例正常大肠粘膜,癌旁粘膜,不同组织类型的癌组织表面进行了观察。正常大肠粘膜的表面超微结构是隐窝分布均匀,排列整齐,覆盖着吸收细胞和杯状细胞。癌旁粘膜表面隐窝结构有不同程度的变形,杯状细胞增多、增大。癌组织表面癌细胞形态特征与深部组织学类型有一定联系,尤其是癌细胞排列不规则及表面微绒毛数量减少,反映了癌组织的分化程度。作者认为应用扫描电镜观察可作为判断大肠癌分化程度的参考指标。     

Abnormal prion protein is associated with changes of plasma membranes and endocytosis in bovine spongiform encephalopathy (BSE)-affected cattle brains

Aims: Transmissible spongiform encephalopathies (TSEs) or prion diseases are fatal neurodegenerative diseases of man and animals characterized by vacuolation and gliosis of neuropil and the accumulation of abnormal isoforms of a host protein known as prion protein (PrP). It is widely assumed that the abnormal isoforms of PrP (PrP^d, disease-specific form of PrP) are the proximate cause of neurodegeneration. Methods: To determine the nature of subcellular changes and their association with PrP^d we perfusion-fixed brains of eight bovine spongiform encephalopathy (BSE)-affected cows and three control cattle for immunogold electron microscopy at two different neuroanatomical sites. Results: All affected cattle presented plasma membrane alterations of dendrites and astrocytes that were labelled for PrP^d. PrP^d on membranes of dendrites and occasionally of neuronal perikarya was associated with abnormal endocytotic events, including bizarre coated pits and invagination of the plasma membrane. BSE-affected cattle also presented excess and abnormal multivesicular bodies, sometimes associated to the plasma membrane perturbations. In contrast, two TSE-specific lesions, vacuolation and rare tubulovesicular bodies, were not labelled for PrP^d as were a number of other nonspecific lesions, such as autophagy and dystrophic neurites. At least two different morphological pathways to vacuoles were recognized. Conclusions: When compared with other TSEs, these changes are common to those of sheep and rodent scrapie and shows that there are consistent membrane toxicity properties of PrP^d. This toxicity involves an aberration of endocytosis. However, it is by no means clear that the lesions are of sufficient severity to result in clinical deficits.     

原子力显微镜在DNA研究中的应用

目的探索原子力显微镜(AFM)研究DNA的分子结构的方法和优势。方法利用该显微镜对DNA分子进行扫描成像。结果AFM能够得到清晰分散的DNA图像，由于针尖的原因，其直径比理论值大。结论AFM在DNA表面结构研究巾的具有很大的优势。     

Evidence for rapid multipolar and slow unipolar production of human cellular and acellular cementum matrix with intrinsic fibers

The genesis of root cementum has been studied infrequently in animal models, e.g., in mice, rats and dogs, but rarely in the human. The present study was based on 8 premolars (4 maxillary and 4 mandibular, 7 first and 1 second) selected from a large collection of freshly extracted human teeth. All teeth were free of disease and presented with roots developed to about 50-80% of their length. After decalcification in EDTA, the apical half of the roots was divided axially into mesial and distal portions. The latter were subdivided into 4 slices cut in the corono-apical direction. These slices were Epon-embedded and cut for examination in the light- and transmission electron microscope. It was found that 2 basically different modes of cementum matrix production occurred at or near the advancing root edge. These 2 modes, i.e., the multipolar versus unipolar matrix production, resulted in either cellular (CIFC) or acellular intrinsic fibre cementum (AIFC). Both varieties did not contain fibres of Sharpey and were restricted to regions of the root usually covered with cellular mixed stratified cementum (CMSC). By comparison with recently published data on the rate of cementum apposition, it is suggested that the multipolar mode is a rapid form, whereas the unipolar mode is a slow-rate form of producing intrinsic fibre cementum.     

Electron-microscopic and morphometric investigation of the action of enkad on retinal photoreceptor cells of campbell rats with hereditary retinal degeneration

Laboratory of Cellular Differentiation, N. K. Kol'tsov Institute of Developmental Biology, Academy of Sciences of the USSR. Department of Pathological Anatomy and Histology, Helmholtz Research Institute of Eye Diseases. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 109, No. 5, pp. 504–506, May, 1990.     

Solitary rectal ulcer

Two cases of solitary rectal ulcer syndrome occurred in an 18-year-old woman and a 24-year-old man. Each had a history of bleeding on defecation, together with constipation alternating with diarrhea. In each case, a solitary rectal ulcer was noted by sigmoidoscopy and confirmed by both light and electron microscopic evaluations of biopsy material. Both clinical and pathologic features of these cases are compatible with classic rectal ulcer syndrome, which has been suggested to result from trauma followed by an ischemic event leading to fibrosis of the mucosa. Fibrosis in these two cases was confirmed by electron microscopy.