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991.
992.
Spleens from 42 patients with polycythemia vera were studied with immunohistologic technics to assess the degree of hematopoietic cellularity in an attempt to clarify the pathogenesis of the splenomegaly characteristic of this disorder. The 22 spleens obtained in the erythrocytotic phase showed striking congestion with mature erythrocytes but no significant extramedullary hematopoiesis. However, the 20 spleens obtained in the spent phase showed prominent trilinear extramedullary hematopoiesis. Increasing splenomegaly with extramedullary hematopoiesis correlated with the development of increased medullary reticulin and peripheral blood leukoerythroblastosis. Splenic myeloid metaplasia is not a feature of uncomplicated polycythemia vera, and its presence indicates progression to the spent phase, or postpolycythemic myeloid metaplasia. The authors' findings indicate that the presence of hematopoietic precursors in the spleen in the spent phase of polycythemia vera and in agnogenic myeloid metaplasia is a result of their filtration from the peripheral blood.  相似文献   
993.
An immune adherence hemagglutination assay (IAHA) and a modified enzyme-linked immunosorbent assay for antigenic characterization of human rotaviruses were developed. The designations of type 1 and type 2 were identical to those established previously by specific complement fixation, enzyme-linked immunosorbent assay, and immune electron microscopy. By IAHA (and modified enzyme-linked immunosorbent assay) certain animal rotaviruses were found to be closely related to human rotavirus type 1. The pattern of IAHA reactivity and the cell culture neutralization serotype were found to be distinct properties. The separation of neutralization and IAHA reactivity was apparent when animal rotaviruses which were distinguishable from each other by neutralization assays were found to share IAHA specificity. Further evidence for the dissociation of the neutralization and IAHA specificities was found in studies of human and bovine rotaviruses which underwent genetic reassortment during coinfection. Thus, it appeared that the IAHA and neutralization antigens were coded for by different genes. In view of these findings, we suggest that the term serotype be reversed to identify the antigen that reacts with neutralizing antibodies as is customary for other viruses and that the term subgroup (instead of serotype) be used for the specificity detected by specific complement fixation, enzyme-linked immunosorbent assay, and now IAHA.  相似文献   
994.
The black patient has a poorer prognosis with arteriosclerotic heart disease than does a white patient and needs a more aggressive approach to reduce cholesterol and other risk factors. The new National Cholesterol Education Panel recommendations are similar to those used in the Multiple Risk Factor Intervention Trial study which lowered cholesterol levels only by 5% to 7% over a seven-year period. We recommend a more aggressive dietary approach introducing the postinfarction patient to a less than 10% fat and 50 mg cholesterol vegetarian diet while recovering in the hospital.  相似文献   
995.
Histiocytic and epithelial cell types share many cytomorphologic and functional characteristics; it is predictable, therefore, that corresponding malignancies might be difficult to distinguish. Described is the case of a 52-year-old woman in whom disseminated anaplastic large-cell lymphoma simulated carcinomatosis by conventional morphologic criteria. Evidence of histiocytic differentiation was derived from immunocytochemical, fine structural, and genetic probe analyses. The diagnosis of histiocytic neoplasia is discussed in relation to categories previously termed malignant histiocytosis, "Ki-1" lymphoma, and regressing atypical histiocytosis, and comparisons are made with animal tumor models.  相似文献   
996.
997.
Fifty-nanometre diameter, clear, synaptic-like vesicles (SLVs) are found in primary mechanosensory nerve terminals of vertebrate and invertebrate animals. We have investigated their role in mechanosensory function using the muscle spindle primary endings of rat Ia afferents as a model. Uptake and release of the synaptic vesicle marker FM1-43 indicated that SLVs recycle like synaptic vesicles and do so in a Ca2+-sensitive manner. Mechanical stimulation increased SLV recycling, increasing both dye uptake and release. Immunogold/electronmicroscopy showed that, like the central synaptic endings, Ia peripheral endings are enriched with glutamate. Moreover, exogenous glutamate enhanced stretch-induced Ia excitability. Enhanced excitability persisted in the presence of antagonists to the commonest ionotropic and metabotropic glutamate receptors (kynurenate, MCPG, CPPG and MAP4). However, excitation by glutamate was abolished by ( R , S )-3,5-dihydroxyphenylglycine (DHPG), and rather more effectively by (2 R ,1'- S ,2'- R ,3'- S )-2-(2'-carboxy-3'-phenylcyclopropyl) glycine (PCCG-13). PCCG-13 also significantly reduced stretch-activated excitability in the absence of exogenous glutamate. These data indicate that SLVs recycle at rest, releasing glutamate, and that mechanical activity increases this process. The blockade with DHPG and PCCG-13 suggests that endogenous glutamate release acts, at least in part, through the recently described phospholipase D-linked metabotropic Glu receptor to maintain the excitability of the sensory endings.  相似文献   
998.
Massimi P  Banks L 《Virology》2000,276(2):388-394
  相似文献   
999.
1000.
The incidence of herpetic keratitis following in-tranasal or direct ocular infection with thymidine kinase-negative (TK?) strains of herpes simplex virus (HSV)-2 has not been well studied, and the role of the TK gene in the establishment of latency and virus reactivation is controversial. To determine whether a TK? strain of HSV-2 could establish trigeminal ganglionic latency and be reactivated in vivo to produce recurrent keratitis or nervous system infection, an animal model of acute and recurrent infection was utilized. Rabbits were infected by the intranasal or ocular routes, and latency was reactivated by immuno-suppression. Virus shedding in nasal and ocular secretions was monitored, and the eyes were examined for the presence of corneal epithelial lesions during acute and reactivated infections. Central nervous system (CNS) and trigeminal ganglionic tissues were assayed by histologic, virologic, and in situ hybridization techniques. All rabbits intranasally infected shed virus in both ocular and nasal secretions, whereas only 30% of rabbits infected in the eyes shed virus in nasal secretions. Virus was recovered from co-cultivation cultures, but not from cell-free ho-mogenates, of trigeminal ganglionic and CNS tissues from animals inoculated by both routes. The incidence of keratitis was much greater after direct ocular inoculation, although both routes of inoculation produced CNS and ganglionic inflammatory lesions. Keratitis healed in 92% of the animals infected by the ocular route by 26 days post infection. Of rabbits initially infected in the eyes and then subjected to drug-induced reactivation, only 30% shed virus, which was limited to a 24 hour period; there was no reappearance of epithelial keratitis, no animal became blind, and none died. In contrast, latently infected control rabbits uniformly reactivated. These studies show that this TK? HSV-2 strain (i) replicates in the eye, (ii) is neuroinvasive but non-neurovirulent following intranasal and direct ocular infection; (iii) sheds in the eye more frequently and for longer periods after ocular than after intranasal inoculation; (iv) induces epithelial keratitis that usually heals spontaneously; (v) establishes latency in trigeminal ganglionic neurons, but no other ganglionic cells; and, (vi) reactivates in a small proportion of animals, but does not produce recurrent ocular lesions following drug-induced immunosuppres-sion. Thus, the TK gene appears directly involved in HSV latency and reactivation in vivo. © 1994 Wiley-Liss, Inc.  相似文献   
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