Schwannian crystalline-like inclusions bodies (Fardeau-Engel bodies) revisited in peripheral neuropathies

In 1969, Fardeau and Engel described polygonal organelles containing crystalline-like structures located in the Schwann cell cytoplasm of unmyelinated fibers. Such inclusions were reported in various conditions, mainly with axonal lesions. They were also reported in a few cases of peripheral neuropathy associated with primary mitochondriopathy. Although they are surrounded by a double membrane, their mitochondrial origin is not definitely proven. Their significance remains obscure but they deserve to be better known as Fardeau-Engel bodies, so as not to be mistaken with mitochondrial crystalline inclusions, which are frequently observed in patients with ragged-red fibers in muscle.     

Lymphatic endothelium isolation,characterization and long term culture

Using a collagenase trypsin-EDTA treatment, we have been able to successfully isolate and grow primary cultures of the lymphatic endothelium (LEC) that were subcultured, frozen for storage, subsequently thawed with good recovery and growth, and serially subcultured. The morphological features of cultured LEC were consistent with that observed for the endothelium of intact lymphatic vessels. A prominent feature of growing cultures was the appearance of large vacuoles in the perinuclear region of the cytoplasm, which became filled with fluid and cell debris engulfed from the culture medium. The basal cell surface lacked a well defined basal lamina and anchoring filaments were observed extending from the basal plasmalemmal surface into the underlying substratum. LEC in cultures were also positive for Factor VIII-related antigen. However, specific granules, characteristic of Weibel-Palade bodies were not observed in ultrathin sections of confluent cultures. F-actin was identified in LEC cultures using fluorescein phalloidin, and in confluent cultures actin filaments were located at the periphery of the cell as a continuous circumferential thin band and short filamentous bundles in the central part of the cell. By using heparin and endothelial cell growth supplement in the culture medium we have been able to grow stable cultures of lymphatic endothelial cells that could be maintained when serially subcultured for over two years. These LEC cultures provide an in vitro model for investigating the function and biochemical properties of the lymphatic endothelium. © 1993 Wiley-Liss, Inc.     

Intracytoplasmic eosinophilic inclusions in the neurons of the central nervous system

Summary This study reports the histological, ultrastructural, and immunocytochemical characteristics of intracytoplasmic eosinophilic inclusion bodies occurring in various types of neurons of the human central nervous system. By light microscopy, the inclusions were brightly eosinophilic, slightly birefringent, and sharply demarcated; they were found in the thalamus in 92% of the cases, in the substantia nigra in 88%, in the locus coeruleus in 45%, and rarely in the spinal cord. Ultrastructurally, the inclusions were composed of assemblies of parallel, alternating dark and light rectilinear profiles. The dark profiles corresponded to thin filaments (microfilaments) that measured 5.5–6.0 nm in diameter. A second set of dense lines crisscrossed the first at right angles. In sections perpendicular to their long axis, the filaments were distributed in a tetragonal lattice pattern in which individual elements occupied the angles of a square. Immunocytochemical preparations for actin were negative. Due to their high rate of occurrence in nonpathological brains, it is thought that the inclusions represent a normal but as yet unidentified cytoplasmic organelle.     

Retinal changes induced by treatment with vincristine and vinblastine

The mitosis-inhibiting Vinca-alkaloids vincristine sulphate and vinblastine sulphate were injected into the vitreous body. This treatment resulted in ultrastructural changes in the retina within an hour. The retinal nerve cells showed a marked increase in the number of cell organelles, including the 100 Å filaments found in their perikarya. The microtubules disappeared and crystalloid structures appeared within an hour. The axons became distended by accumulated cell organelles, usually surrounding a crystalloid. The synaptic bodies, especially the presynaptic ones, often contained crystalloids, and showed a transient increase in the number of synaptic vesicles. The inner segments of the photoreceptor cells showed similar ultrastructural alterations, and, in addition, stacks of membranous structures. The outer segments decreased in length, and only rudiments of these structures remained one week after the intravitreal injection. The non-pigmented epithelial cells and the Müller's neuroglial cells also showed marked structural alterations.These ultrastructural changes are consistent with the biochemical and fluorescence microscopic observations that vincristine and vinblastine both inhibit the intracellular flow of cell constituents, as previously demonstrated to be the case with colchicine. It is proposed that the structural changes in the individual cells reflect the drug-induced imbalance between the inhibited intracellular transport and the continued formation of the cell constituents characteristic of the afflicted cell.This study was supported by grants from M. Bergwalls Stiftelse, W. and M. Lundgrens Stiftelse, H. Hiertas Stiftelse, Swedish Medical Research Council (B 72-12 X-2543-04 A) and the Swedish National Cancer Society (265 - B 70-02 X).     

An Italian family with autosomal recessive quadriceps-sparing inclusion-body myopathy (ARQS-IBM) linked to chromosome 9p1

We report an Italian family with autosomal recessive quadriceps-sparing inclusion-body myopathy (ARQS-IBM). The patients (two second cousins) developed a slowly progressive distal and proximal myopathy with complete sparing of the quadriceps. Muscle biopsy showed rimmed vacuoles in numerous muscle fibers, and electron microscopy documented accumulation of 15–21 nm filaments, DNA analysis established linkage to 9p1 and haplotype analysis revealed that the patients shared a recombined common haplotype. The gene locus of ARQS-IBM was initially mapped to chromosome 9p1-q1 in families of Iranian-Jewish origin and later confirmed in a few other ethic groups. This is the first report of Italian patients with ARQS-IBM showing positive linkage to chromosome 9p1. Our data suggest that patients having distal and proximal myopathy with rimmed vacuoles and possible recessive inheritance, often classified as distal myopathies, should be thoroughly investigated according to the diagnostic criteria of h-IBM and, when positive, studied for linkage to chromosome 9p1. Received: 8 February 2000 / Accepted in revised form: 6 April 2000     

循经感传现象产生机理的探讨

目的：探讨外周感觉神经末梢间是否存在跨节段的远距离信息传递以及此信息传递的特点。方法：分离神经细束，观察逆行电刺激大鼠脊神经背侧皮支后，相距较远的神经细束上机械感受单位的电活动变化。结果：记录的单位主要是Aδ和C类单位，其感受野多位于距背中线0.5-2.0cm的范围内。机械感受单位一般在距节段电刺激后的91－120s传入放电增加；刺激T9在T12记录的单位和刺激T12在T9记录的单位，二者放电增加反应相似；另外，T10、T11脊神经与中枢断开和不断开两种情况下所记录的单位放电也未见明显不同。结论：外周末梢间的信息传递具有传导速度较慢，传递线路相对稳定，且具有不受中枢调控和双向性的特点，可能是形成循经感传的生理学基础。     

Filament systems in Purkinje cells of the sheep heart: Possible alterations of myofibrillogenesis

The Purkinje cells of the sheep heart contain several types of filament arrays. Numerous filaments not related to myofilaments but intermediate in diameter between thick and thin myofilaments are found. In addition, these cells contain filamentous structures (leptomeres and myofilament complexes) derived from myofibrillar components. Thickened Z-bands and other defects in “normal” myofibrils and defects in the insertion of myofibrils at the sarcolemma also occur in these cells. These myofibrilrelated structures and defects in “normal” myofibrils are interpreted as arising from alterations in the assembly of myofibrils. It is proposed that these defects in myofibrillogenesis are a result of decreased selection for contractile properties in Purkinje cells whose main function is impulse conduction.