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Olfactory Schwann cells are derived from precursor cells in the olfactory epithelium 总被引:4,自引:0,他引:4
In this morphological and immunohistochemical study we show that olfactory schwann cells (OSC) are derived from precursor cells residing in the olfactory epithelium. During development, they migrate out of the epithelium and extend processes to ensheath the olfactory axons. Olfactory mucosa from E14 rat embryos and juvenile rats were treated with trypsin-pancreatin to remove the underlying connective tissue. The epithelial explant was then maintained for two days in culture, during which cells migrated out from the explant. Among them were spindly bipolar cells which were identified as OSC by their positive immunoreaction for glial fibrillary acidic protein, ultrastructure, and association with growing axons. Axonal growth was significantly more profuse in the embryonic explants, in which the polarity of the OSC was oriented parallel with the axons. Ultrastructural observations showed that ensheathment of the bundles of axons resembled those in vivo. 相似文献
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Olfactory tissues from human fetuses (17.5-28 weeks of gestation) were stained by immunofluorescence for neural cell adhesion molecules (N-CAMs). Staining for N-CAMs was most prominent in the olfactory nerve bundles in the lamina propria, while in the olfactory epithelium, it was present on the olfactory receptor neurons and globose basal cells. The basal cells proper and supporting cells lacked N-CAMs. In the olfactory bulb, only the olfactory nerve and glomerular layers showed moderate labeling for N-CAMs. Western blot analysis showed that the N-CAMs of the fetal human primary olfactory pathway consisted of three molecular isoforms, N-CAM180, N-CAM140 and N-CAM120. 相似文献
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Tan PH Jayabaskar T Chuah KL Lee HY Tan Y Hilmy M Hung H Selvarajan S Bay BH 《American journal of clinical pathology》2005,123(4):529-540
We aimed to establish whether morphologic parameters were prognostically important in a large series of breast phyllodes tumors in Asian women. Of 335 phyllodes tumors diagnosed at the Department of Pathology, Singapore General Hospital, Singapore, between January 1992 and December 2002, 250 (74.6%) were benign, 54 (16.1%) borderline, and 31 (9.3%) malignant, based on histologic review of archival slides. Of the women, 43 (12.8%) experienced recurrences during the follow-up period. Recurrent disease was correlated with grade or classification (P = .028), stromal atypia (P = .016), stromal hypercellularity (P = .046), and permeative microscopic borders (P = .021). Multivariate analysis revealed that independent predictors of recurrence were pseudoangiomatous stromal hyperplasia (PASH) and margin status, whereby the presence of PASH and complete or negative margins reduced recurrence hazards by 51.3% and 51.7% respectively. The 7 women who died of disease during follow-up had malignant phyllodes tumor at the outset and experienced recurrences, and death was preceded by distant metastases. 相似文献
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Light microscopic observations indicated that cellular differentiation of the primary olfactory pathway in human fetuses was relatively advanced by the end of the first trimester. However, immunohistochemical staining showed that olfactory marker protein was present in the receptor cells only at about 28 weeks post-conception. At about 32 weeks, modest amounts of the protein could be found in the peripheral olfactory nerve layer and a few glomeruli, with increased staining observed in subsequent weeks. The results show conclusively that human fetal olfactory neurons synthesize olfactory marker protein during the later half of gestation. 相似文献
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Morphological and functional plasticity of olfactory ensheathing cells 总被引:12,自引:0,他引:12
In the primary olfactory pathway, olfactory ensheathing cells (OECs) extend processes to envelop bundles of olfactory axons
as they course towards their termination in the olfactory bulb. The expression of growth-promoting adhesion and extracellular
matrix molecules by OECs, and their spatially close association with olfactory axons are consistent with OECs being involved
in promoting and guiding olfactory axon growth. Because of this, OECs have been employed as a possible tool for inducing axonal
regeneration in the injured adult CNS, resulting in significant functional recovery in some animal models and promising outcomes
from early clinical applications. However, fundamental aspects of OEC biology remain unclear. This brief review discusses
some of the experimental data that have resulted in conflicting views with regard to the identity of OECs. We present here
recent findings which support the notion of OECs as a single but malleable phenotype which demonstrate extensive morphological
and functional plasticity depending on the environmental stimuli. The review includes a discussion of the normal functional
role of OECs in the developing primary olfactory pathway as well as their interaction with regenerating axons and reactive
astrocytes in the novel environment of the injured CNS. The use of OECs to induce repair in the injured nervous system reflects
the functional plasticity of these cells. Finally, we will explore the possibility that recent microarray data could point
to OECs assuming an innate immune function or playing a role in modulating neuroinflammation. 相似文献
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Intracranial germ cell tumours are rare. The incidence of primary intracranial yolk sac tumour is even more uncommon, with only two reported cases being associated with Down's syndrome in the English literature. This report details the findings of yolk sac tumour in the pineal region affecting a 22 year old Chinese man with Down's syndrome. Histology revealed yolk sac tumour with only a solid pattern, potentially mimicking the more common germinoma in the pineal region. No other germ cell components were identified. This is the third report of intracranial yolk sac tumour manifesting in a patient with trisomy 21. The pathology of this tumour and its differential diagnoses are discussed. 相似文献
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