Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase activities in early stages of development in dystrophic chickens

Glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconate dehydrogenase (6PGDH) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) activities were assayed in superficial pectoral muscles of hereditary dystrophic chickens, 1 week, 2 weeks, 4 weeks and 4 months after hatching. In control chickens, activities of G6PDH and 6PGDH were very low at 4 months of age; however, at 1 week of age, they were much higher than those at 4 months of age. Activities of G6PDH and 6PGDH were significantly higher in dystrophic chickens compared with those in the controls at all the stages of development studied. These findings suggest that considerable activities of G6PDH and 6PGDH are present within the pectoral muscle cells at early stages of development, at least in dystrophic chickens. GAPDH activity was significantly lower in dystrophic chickens at 2 weeks, 4 weeks and 4 months of age compared with those in control chicken. These findings together with our previous studies (Mizuno 1984a,b) in which increased activities of superoxide dismutases, catalase, glutathione peroxidase and glutathione reductase were reported in dystrophic chickens, indicate the presence of an increased capacity for the turnover of oxygen-free radicals within muscle cells in dystrophic chickens, and that oxygen-free radicals and the related activated oxygen species may be playing a role in inducing cellular damage.     

Alpha-synuclein pathology of the spinal and peripheral autonomic nervous system in neurologically unimpaired elderly subjects

Studies on cases with incidental Lewy body disease (ILBD) suggest that alpha-synuclein (alphaSN) pathology of Parkinson's disease (PD) starts in lower brainstem nuclei and in the olfactory bulb. However, medullary structures as the induction site of alphaSN pathology have been questioned as large parts of the nervous system, including the spinal cord and the peripheral autonomic nervous system (PANS), have not been examined in ILBD. Thus, the time course of PD lesions in the spinal cord or PANS in relation to medullary lesions remains unknown. We collected 98 post mortem cases with no reference to PD-associated symptoms on clinical records. alphaSN pathology was found in the central nervous system, including the spinal cord, and in the PANS in 17 (17.3%) cases. alphaSN pathology was encountered in autonomic nuclei of the thoracic spinal cord, brainstem and olfactory nerves in 17/17, in sacral parasympathetic nuclei in 15/16, in the myenteric plexus of oesophagus in 14/17, in sympathetic ganglia in 14/17, and in the vagus nerve in 12/16 cases. In addition to the thoracic lateral horns, a high number of alphaSN lesions was also found in non-autonomic spinal cord nuclei. Considering supraspinal structures our cases corresponded roughly to the recently described sequential order of alphaSN involvement in PD. Our study indicates, however, that the autonomic nuclei of the spinal cord and the PANS belong to the most constantly and earliest affected regions next to medullary structures and the olfactory nerves. A larger cohort of ILBD cases will be needed to pinpoint the precise induction site of alphaSN pathology among these structures.     

Combination therapy prevents amyloid-dependent and -independent structural changes

Neuropathological features of Alzheimer's disease (AD) are recapitulated in transgenic mice expressing familial AD-causing mutations, but ectopic transgene overexpression makes it difficult to relate these abnormalities to disease pathogenesis. Alternatively, the APP/PS-1 double knock-in (DKI) mouse produces mutant amyloid precursor protein (APP) and presenilin-1 (PS-1) with normal levels and regulatory controls. Here, we investigated effects of amyloid on brain structure and neuroplasticity by vaccinating DKI mice with amyloid-β starting at 8 months of age. At 14 months, vaccination blocked cerebral amyloid deposition and its attendant microglial activation. Neuropil abnormalities were pronounced only within plaques, and included circumscribed loss and dysmorphology of axons, dendrites, terminals and spines. Blockade of amyloid deposition restored neuropil integrity. Amyloid removal did not rescue reductions in the hippocampal neural progenitor and neuroblast populations, but adding 1 month of voluntary exercise to amyloid-β vaccination markedly stimulated hippocampal neurogenesis. These results identify amyloid-dependent and -independent structural changes in the DKI mouse model of AD. Combining exercise with amyloid-directed immunotherapy produces greater restoration of brain structure and neuroplasticity than is achieved with either maneuver alone.     

Glutamate transport in cultures from developing avian cerebellum: Presence of GLT-1 immunoreactivity in Purkinje neurons

Immunocytochemical studies indicated that Purkinje cells cultured from chick embryonic cerebellum (embryonic day 8) strongly express a glutamate transporter EAAT2 cloned from human brain (GLT-1 in rat brain). At both 7 days and 14 days in culture, Purkinje neurons accumulated 1 μM [³H]L -glutamate via a potent “high-affinity” transport system that could be inhibited by D - and L -threo-3-hydroxyaspartate (D - and L -t-3OHA) and by L-trans-pyrrolidine-2,4-dicarboxylate (L -t-PDC). The order of potency of the three inhibitors was L -t-PDC ∼ L -t-3OHA > D -t-3OHA. Only the value of IC₅₀ (concentration causing 50% inhibition) for D -t-3OHA significantly changed between 7 days (116 μM) and 14 days in culture (40 μM). All n_H ∼ 1, except in the case of the inhibition by D -t-3OHA at 14 days in culture (n_H = 0.57), indicating the possible appearance of heterogeneity of the transport sites at later stages of culturing. Chronic inhibition of L -glutamate transport by L -t-PDC resulted in major changes in the morphology of Purkinje cells; particularly, the neurites almost completely regressed. J. Neurosci. Res. 54:595–603, 1998. © 1998 Wiley-Liss, Inc.     

Neuronal differentiation of chromaffin cells in vitro,induced by extremely low frequency magnetic fields or nerve growth factor: A histological and ultrastructural comparative study

The application of nerve growth factor (NGF) to primary adrenal medulla chromaffin cell cultures induces phenotypic changes characterized mainly by the presence of neurites. A similar effect has been seen when these cells are stimulated by extremely low frequency magnetic fields (ELFMF). In this study, newborn rat chromaffin cells were cultured and subjected to NGF or ELFMF in order to compare their histological and ultrastructural characteristics. Cells cultured in the presence of NGF developed cytoplasmic projections and their distal ends showed growth cones as well as filopodia. With scanning and transmission electron microscopy, an increased submembranous electron density was observed in the nuclei of cells as well as irregular, wavy neuritic projections with a moderate number of varicosities, as well as the prevalence of intermediate filaments among the cytoskeleton components. Cells stimulated with ELFMF presented straighter neuritic extensions with a greater number of varicosities. With the transmission electron microscope, numerous neurotubules were observed, both in the cell soma and in their neuritic extensions. In both groups, growth cones were clearly identified by their ultrastructural characteristics. The differences seen in the cytoskeleton of cells stimulated with NGF or ELFMF suggest differential stimulation mechanisms possibly determining the biochemical, electrophysiological, and morphological characteristics in both types of cell cultures. J. Neurosci. Res. 53:569–582, 1998. © 1998 Wiley-Liss, Inc.     

Atrium of stone: A case of confined left atrial calcification without hemodynamic compromise

Dystrophic cardiac calcification is often associated with conditions causing systemic inflammation and when present, is usually extensive, often encompassing multiple cardiac chambers and valves. We present an unusual case of dystrophic left atrial calcification in the setting of end stage renal disease on hemodialysis diagnosed by echocardiography and computed tomography. Significant calcium deposition is confined within the walls of the left atrium with no involvement of the mitral valve, and no hemodynamic effects.     

1例DEB的基因突变研究

目的检测1例营养不良型大疱性表皮松解症(DEB)家系的基因突变位点。方法对1例DEB患者及其家属成员采用聚合酶链反应及DNA直接测序方法进行COL7A1基因突变检测。结果患者存在COL7A1上第6240位鸟嘌呤G被腺嘌呤A代替(G→A),使得2043位的甘氨酸被精氨酸替代(G2043R),其父母、妹妹及健康人未见此突变。结论COL7A1基因的G2043R突变可能是引起本例临床表现的原因,且是一个denovo突变。     

罕见亚型大疱性表皮松解症3例及家系调查

【摘要】 目的 报道3例罕见亚型遗传性大疱性表皮松解症（EB）。方法 收集先证者及其亲属的临床资料,全外显子测序筛查先证者致病基因,采用Sanger或qPCR测序对患者及其亲属进行突变验证。结果 例1表现为背部线状红色瘢痕,患者及有相似临床表现的母亲、无症状女儿均携带COL7A1基因c.4573G>A（p.Gly1525Arg）突变。例2表现为全身网状色素沉着,偶伴手足水疱,携带KRT5基因c.74C>T（p.Pro25Leu）新发突变。例3表现为曝光部位为主的色素异常伴左手不完全并指,先证者携带FERMT1基因2-6号外显子纯合缺失突变,分别来自无症状父母。例1诊断为显性痒疹型营养不良型 EB, 例2诊断为斑驳色素型单纯型EB, 例3诊断为Kindler EB。结论 EB临床异质性高,基因检测对于罕见亚型EB的明确诊断非常重要。     

Multichannel cochlear implants: relation of histopathology to performance

OBJECTIVES: To determine the relationship of surviving neural elements to auditory function in multichannel cochlear implant temporal bones. STUDY DESIGN: Case series of all 14 existing multichannel cochlear implants in our temporal bone collection. METHODS: Devices included Nucleus 22 (n = 11), Nucleus 24 (n = 1), Ineraid (n = 1), and Clarion (n = 1). Morphologic evaluation of structural elements including spiral ligament, stria vascularis, hair cells, peripheral processes, and spiral ganglion cells was performed. Clinical performance data were obtained from patient charts. For eight patients, nonimplanted contralateral temporal bones were available and paired comparisons were made. RESULTS: Despite frequent absence of hair cells and peripheral processes, all bones had at least some remaining spiral ganglion cells. Percent of normal remaining structures were unrelated to auditory performance with the implant for any of the structural elements. Ganglion cell count in segment III showed significant negative correlations to speech discrimination scores for words and sentences (Rhos = -.687 and -.661, P < or = .03 and .04) as did segment IV and total ganglion cell count with word score (Rhos = -.632 and -.638; P < or = .05). Spiral ganglion cell survival did not differ between implanted and nonimplanted ears, with the exception of segment I, which had fewer cells in the implanted ear (P < or = .028). CONCLUSIONS: Performance variability of cochlear implants cannot be explained on the basis of cochlear neuronal survival. Although hair cells and peripheral processes were frequently absent or greatly diminished from normal, all subjects had at least some spiral ganglion cells. And, in this series, there was an inverse relationship between survival of ganglion cells and performance.     

Induction of axon and dendrite formation during early RGC-5 cell differentiation

The retinal ganglion cell (RGC)-like RGC-5 line can be differentiated with staurosporine to stop dividing, extend neurites, and increase levels of several ganglion cell markers. This allows study of regulation of neurite development on a single cell basis. However, it is unclear whether the neurites induced by differentiation have features characteristic of dendrites or axons. To address this question, RGC-5 cells were differentiated with staurosporine and then immunoblotted for microtubule-associated protein 2 (MAP2) and actin, or stained immunocytochemically for different MAP2 isoforms, tau, growth-associated protein 43 (GAP-43), or the neuronal marker beta-III-tubulin. We found that staurosporine-induced differentiation led to an upregulation of MAP2c, a MAP2 isoform expressed in developing neurons. Some neurites expressed MAP2c but not the dendritic markers MAP2a and MAP2b, consistent with an axonal phenotype. Some neurites expressed the axonal marker tau in a characteristic proximal-to-distal gradient, and had GAP-43 labeling characteristic of axonal growth cones. The presence of MAP2c in differentiated RGC-5 cells is indicative of RGC-like neurite development, and the pattern of staining for the different MAP2 isoforms, as well as positivity for tau and GAP-43, indicates that differentiation induces axon-like and dendrite-like neurites.