氯地滴眼液对家兔眼压及房角组织影响的研究

目的 观察氯地滴眼液对家兔眼压及房角组织影响。方法 用６０只家兔设实验和对照组,以含０．１７５％氯霉素和０．１５％地塞米松的氯地跟液滴眼,每日４次,生理盐水对照。于１／２、１、２、３月测眼压后处死家兔以电镜观察房角组织变化。结果 眼压和房角组织结构与对照组无明显差异。结论 临床应用氯地眼液３月内是安全的。     

Effects of 8-methoxypsoralen plus 365 nm UVA light on Candida albicans cells

Summary Candida (C.) albicans cells were exposed to 8-Methoxypsoralen (8-MOP) concentrations of 1.0 g/ml and 10.0 g/ml medium and irradiated with 365 nm light. The amount of energy emitted was 4.8 J/cm². Two divergent types of cell damage occured concerning yeast cell cytoplasm and cell wall. Two hours after exposure cytoplasmic changes involving mitochondria, which showed irregularities in shape, blurred appearance or loss of mitochondrial cristae and outer membrane were seen. The number of vacuoles was increased. The cytoplasm showed large electron transparent areas, the cytoplasmic membrane disappeared in some areas completely. Nucleus and nuclear envelope usually remained intact in early stages. 24h after exposure conspicuous cell wall alterations were observed in addition to cytoplasmic changes. Newly produced cell wall material formed ball-like protrusions or was adherent sickle-shaped to the cell wall. The investigations strongly suggest that the results found after 8-MOP-UVA treatment of C. albicans cells can not be interpreted in the sense of a general cytotoxic effect. Apparently it takes the form of a combination of events involving regressive and progressive alterations.     

The role of postischemic recirculation in the development of ischemic neuronal injury following complete cerebral ischemia

Summary The neuronal response to complete cerebral ischemia (CCI) of 5–15 min duration was evaluated at the light and electron microscopic level subsequent to postischemic recirculation periods of up to 60 min. Following postischemic reperfusion, the homogeneous neuronal changes characteristic of permanent CCI were modified into a heterogeneous pattern of selectively vulnerable neuronal responses. Four basic types of neuronal injury were represented within this heterogeneous neuronal population. The Type I neuronal response was most numerous and consisted of chromatin clumping, nucleolar condensation and a breakdown of polysomes. This response may represent a reversal of some of the neuronal changes observed after permanent CCI. In addition to the above changes, Type II neurons contained swollen mitochondria and Golgi saccules which appeared as microvacuoles under the light microscope. Type III neurons displayed varying degrees of neuronal shrinkage and numerous swollen mitochondria. Type IV neurons were markedly shrunken and electron-dense with few identifiable subcellular structures. The distribution of Type I neurons was random but the other neuronal responses occurred in selectively vulnerable brain regions. The number of Type II, III, and IV neurons increased with extended insult durations but were unaffected by the length of recirculation. Ten minutes of CCI represented the threshold for a significant increase in the number of severely altered neurons. These findings suggest that considerable neuronal injury may be present after 10–15 min of CCI, and the lack of a recirculation period following CCI appears to afford the brain parenchyma an extensive degree of structural protection.Supported by PHS Grant NS-12587     

Hexachlorophene and the central nervous system

Summary A study on hexachlorophene encephalopathy in mice and baboons is reported. By light microscopy, a severe spongiform lesion of the central nervous system (CNS) was localized in the white matter, without myelin breakdown or cellular reaction. By electron microscopy, the myelin alteration was characterized by wide intralamellar spaces or splitting developed in the intraperiod line of compact sheaths. The acute changes described were induced by administration of the drug by the digestive or cutancous routes at various dosage levels in an aqueous solution or in talcum powder. The toxic effects depended on the age of the animals, the survival times and the concentrations of hexachlorophene, i.e., 6%, 3%, and 0.5%. The findings are compared with previous reports on the neurotoxicity of hexachlorophene and other chemicals in humans and experimental animals. Hexachlorophene cannot be recommended for use in young infants because of its neurotoxicity in very low doses as demonstrated in the present report.     

Neurofibrillary tangles and Lewy bodies in the locus ceruleus neurons of the aged brain

Summary The presence of Lewy body and neurofibrillary tangle in the locus ceruleus neurons of aged brain is described. Ultrastructural study revealed that in some Lewy bodies the presence of twisted tubules or paired helical filaments amongst the filaments of the Lewy body. A quantitative analysis of serial sections of locus ceruleus from aged brain, incidences of the Lewy body and neurofibrillary change were 0.07% (9/11,515) and 6.6% (15/11,515), respectively. The incidence of neurons containing both structures was 0.008% (1/11,515).     

Experimental vaccinia virus meningoencephalitis in adult albino mice: Virological,light microscopic and ultrastructural studies

Summary Adult NMRI mice were inoculated intracerebrally with 1.5–5×10² pfu of the neurovirulent strain Ma1 of vaccinia virus. The animals usually became diseased on day 3 and died on day 5 or 6 p.i. Infectivity assay studies on the mouse brains yielded a steeply rising viral titer comparable with that exhibited by several other so-called neurovaccinia strains after intracerebral inoculation. Histological studies revealed a patchy leptomeningitis most apparent over the basal brain surface. Mononuclear elements of varied size were the most common infiltrate cells in the meningitic lesions. These often showed a pronounced hemorrhagic and necrotizing character. In some places, the cellular infiltrates within the subarachnoid space extended along the perforating vessels into the superficial cerebral cortex. By electron microscopy, all essential stages of virus morphogenesis including the discharge of mature virions could be seen in numerous mononuclear phagocytes and adventitial cells. In contrast to this, no unequivocal neuroectodermal cell showed morphologic evidence of productive viral infection. Likewise, no endothelia or vascular myocytes were encountered which contained newly formed virus particles. However, alterations of the walls of blood vessels and signs of disturbed vascular permeability were a frequent finding in the meningeal foci of inflammation as well as in and around the track left by the inoculating needle. Another ultrastructural feature of the meningitic lesions was the widespread occurrence of degenerating or disintegrating infiltrate cells both infected and uninfected ones.The virologic and morphologic findings observed in this model of experimental vaccinia virus meningo-encephalitis are discussed with regard to data previously published by other authors. The propensity of strain Ma1 of vaccinia virus (and most probably of other so-called neurovaccinia strains) for replication in mesenchymal cells in particularly emphasized.     

The ultrastructure of the extracellular phase of bone as observed in frozen thin sections

Summary The fine structure of the extracellular phase of avian medullary bone and embryonic chick femur was examined in thin sections prepared by ultracryotomy and ultramicroincineration. Since contact with solutions was completely avoided, little or no loss or dislocation of mineral constituents could occur. Amorphous bone mineral (ABM) was present in two forms: as 15–30 nm spheres and as a structure-free haze. Removal of all organic material by low temperature ashing left the ABM intact. Crystals were usually associated with the ABM. In newly ossifying regions clusters or nodules of randomly oriented crystals and ABM appeared to coalesce when they reached approximately 1 m in diameter. In highly calcified regions crystals appeared to be oriented along collagen fibers. ABM did not appear to be associated with collagen. Unmineralized collagen was visible in osteoid after staining with dry OsO₄ vapor and it appeared to be diverted around nodules. Structures which resembled matrix vesicles were present. Selected area electron diffraction patterns indicated the presence of hydroxyapatite.     

Cancellous bone in the anterior part of the iliac crest

Summary Calcified tissue in the iliac crest and the adjoining ala of the ilium was investigated by scanning electron micrographs of thick, polished sections from which the marrow had been removed. Some quantitative properties of the trabeculae and of the marrow spaces were obtained from measurements on the images of the polished surfaces. Most of the cortex of the crest was porous, about 25% void, of varying thickness, intruding into the cancellous space in some regions. A structure containing about 35% by volume of bone was found at and near the anterior superior spine. Compact bone of normal appearance began as thin medial and proximal sheets below the crest, and thickened until at 20–30 mm it was substantial. The cancellous bone contained by these structures was varied. Two main zones were distinguished, whose junction ran from just below the anterior superior spine to the lower portion of the iliac fossa. In the lateral zone, adjacent to the crest, there were arch-like structures, commencing from the medial and proximal walls, and meeting, or even crossing, near the centre. The medial zone was distinguished by large marrow cavities and strongly orientated trabeculae. The relative volume of bone was similar in the two zones, falling from a maximum of 15–20% to about 5% in the regions of the anterior inferior spine and the iliac fossa. The average width of the trabeculae was significantly greater in the medial than in the lateral zone (W _b (m)0.16 mm, W_b(l)0.12 mm). Inclusions of very heavily constructed trabeculae, having average widths of about 0.35 mm, were found in both zones.     

Dynamic aspects of peripheral nerve changes in progressive neural muscular atrophy

Summary Serial nerve biopsies were performed at an early, and at an advanced stage of the disease in 2 patients with progressive neural muscular atrophy. The early biopsy showed a complete loss of the large diameter and thickly myelinated fibres, as well as an expansion of the endoneurial interstitium in both cases. Myelinated and unmyelinated fibres exhibited axonal degeneration in all biopsies occasionally. Onion bulb formation, a typical feature of peripheral neuropathy in neural muscular atrophy, was found to be prominent only in the latter biopsies. As regards the formal pathogenesis of hypertrophic neuropathy in neural muscular atrophy, axonal dystrophy and interstitial changes of the endoneurium were regarded as primary phenomena, demyelination and onion bulb formation as secondary. A possible causal relation between axonal dystrophy and interstitial changes, observed in these cases, is discussed in the light of the present literature.

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Zusammenfassung Bei 2 Patienten mit progressiver neuraler Muskelatrophie wurden Nervenbiopsien jeweils in einem frühen und in einem fortgeschrittenerem Stadium der Erkrankung entnommen und verglichen. In beiden Fällen zeigten bereits die frühen Biopsien ein völliges Fehlen der großkalibrigen, dickbemarkten Axone. Ebenfalls als frühe Veränderung wurde eine Erweiterung des endoneuralen Interstitiums festgestellt. Eine geringe Anzahl der vorhandenen bemarkten und unbemarkten Axone in allen Biopsien wies degenerative Veränderungen auf. Die für die progressive neurale Muskelatrophie typische Zwiebelschalenbildung der Schwannschen Zellen — möglicherweise eine Reaktion auf wiederholte De-und Remyelinisierungsvorgänge um dystrophische Axone — trat erst in den späteren Biopsien deutlicher hervor. Hinsichtlich der formalen Genese der hypertrophischen Neuropathie bei neuraler Muskelatrophie sind nach diesen Beobachtungen axonale Dystrophie und interstitielle Veränderungen des Endoneuriums als primäre Entmarkung und Zwiebelschalenbildung als sekundäre Phänomene zu betrachten. Die Möglichkeit einer kausalen Beziehung zwischen axonaler Dystrophie und interstitiellen Veränderungen wird an Hand der vorliegenden Befunde und Literatur diskutiert.

     

The effect of grinding of human dentine examined by X-ray diffraction, infrared spectroscopy, and electron microscopy

Analysis of human dentine by infrared spectrophotometry suggests that ball-grinding may result in damage of the apatite crystallites. The present study includes further assessments of this effect by X-ray diffraction, infrared spectroscopy, and electron microscopy. Each of three coarse-ground dentine samples (Group I) was divided into three portions of 30 mg. One of these portions was ball-ground for approximately 1 min (Group II), the second portion for 6 min (Group III), and the third portion for 23 min (Group IV). The 002 reflection showed line broadening, most marked from Group II to III. Electron microscopy showed a gradual change in crystallite appearance with increased grinding, most pronounced from Group II to III. These observations indicate that by prolonged grinding a limit is approached where no further changes in the crystallites occur. Electron microscopy also indicated that fracture of the crystallites might have occurred. This was probably accompanied by strains in the lattice. The infrared spectra indicated that no breakdown of the apatite structure had occurred during the entire grinding.