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81.
Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation 总被引:5,自引:12,他引:5
Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death. 相似文献
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Deborah W. Sevilla Erin M. Weeden Suzy Alexander Vundavalli V. Murty Bachir Alobeid Govind Bhagat 《Virchows Archiv : an international journal of pathology》2009,455(4):323-336
Different patterns of bone marrow (BM) infiltration by diffuse large B cell lymphomas (DLBCL) have been described. A pure
nodular pattern is uncommon, and the pathologic features, as well as the clinical correlates of DLBCL manifesting this pattern
in the BM have not been well characterized. We evaluated BM biopsies involved by large B cell lymphomas diagnosed at our institute
over an 11-year period to assess the morphology, phenotype, cytogenetic abnormalities, and clinical features of cases associated
with a nodular pattern. A distinct nodular pattern of BM involvement was noted in 14 out of 55 (25%) cases. Although both
EBV+ and EBV− DLBCL with this pattern were identified, a pure nodular pattern was significantly more common in EBV+ DLBCL
compared to EBV− DLBCL (8/9, 89% versus 6/46, 13%; P = 0.00002). The majority of EBV+ DLBCL associated with a nodular pattern had distinctive morphologic features (polymorphic
cellular infiltrate and pleomorphic cytology), and CD30 expression was more commonly observed in this group (P = 0.0163). All EBV+ DLBCL and two out of six (33%) EBV− DLBCL had nongerminal center phenotypes. No recurrent cytogenetic
abnormalities were detected in either group. Importantly, all EBV+ DLBCL occurred in individuals with immune dysfunction (organ
transplant recipients, HIV infection) or in those >50 years of age. Our study indicates a much higher predilection for EBV+
DLBCL to involve the marrow in a nodular pattern compared to EBV− cases and highlights similarities in the morphologic pattern
of BM involvement by previously recognized subsets of immunodeficiency-related EBV + lymphomas and the newer entity of “EBV+
DLBCL of the elderly.” 相似文献
85.
Hereditary haemorrhagic telangiectasia (HHT) is an autosomal dominant disorder affecting blood vessels of the skin, mucous membrane and viscera. The otorhinolaryngologist is the commonest clinician involved in management as epistaxis occurs in 93% of the patients. 1 As marked advances have recently been made regarding the pathogenesis and management of the condition, the otorhinolaryngological perspective is reviewed. 相似文献
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Successful intracytoplasmic sperm injection with spermatozoa from a patient with dysplasia of the fibrous sheath and chronic respiratory disease 总被引:5,自引:4,他引:1
The present report describes a successful intracytoplasmic sperm injection
(ICSI) procedure performed with immotile spermatozoa from a young man with
a combination of dysplasia of the fibrous sheath and dynein deficiency, a
recently described variant of the immotile cilia syndrome. This methodology
provides the only suitable solution for these patients in whom all other
assisted fertilization technologies have previously failed, and opens the
possibilities for treatment of male infertility due to severe, irreversible
sperm defects such as the one reported here.
相似文献