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排序方式: 共有1049条查询结果,搜索用时 15 毫秒
21.
Carrier detection in hemophilia A: a cooperative international study. I. The carrier phenotype 总被引:1,自引:0,他引:1
Graham JB; Rizza CR; Chediak J; Mannucci PM; Briet E; Ljung R; Kasper CK; Essien EM; Green PP 《Blood》1986,67(6):1554-1559
Eight laboratories in six countries cooperated to clarify several issues concerning the phenotypes of heterozygous carriers of hemophilia "A." Plasma levels of factor VIII (F.VIII:C, formerly VIII:C) and von Willebrand factor (VWF:Ag, formerly VIIIR:Ag) of carriers and normal women were determined by various "in-house" methods; a single lyophilized plasma standard was used for all assays. Analysis of the collated data from 336 carriers (296 obligatory carriers and 40 sporadic carriers) and 137 normal women showed that there was no difference in the F.VIII:C levels of "paternal" carriers (women who had obtained the abnormal gene from their fathers) and "maternal" carriers. Neither was there a difference in the VWF:Ag levels of normal women and either type of carrier. Age was found to have a significant effect on both F.VIII:C and VWF:Ag, values being higher at very young and very old ages, the minima occurring in the 25- to 30-year range. ABO blood type had a striking effect. Women of types A, B, and AB (designated non- O in the study), both normals and carriers, had significantly higher levels of both factors than did women of type O. Analysis by laboratories showed that differences in mean levels of both factors between laboratories were highly significant. It was concluded that age, ABO blood type, and laboratory variation should be taken into account in carrier detection. 相似文献
22.
Sera from dogs rendered aplastic by total-body irradiation stimulate human bone marrow megakaryocyte progenitors to form megakaryocyte colonies in plasma clot cultures. In this investigation, we evaluated the effects of varying concentrations of such sera on both the mitotic and endomitotic phases of human megakaryocyte development in vitro. When low concentrations of aplastic canine sera (2.5% to 5.0% [vol/vol]) were added to cultures of human peripheral blood mononuclear cells in place of normal AB serum, megakaryocyte colony formation was augmented fivefold, cell numbers per colony increased approximately 2.5- fold, and the geometric mean megakaryocyte ploidy almost doubled. Further increasing the aplastic canine serum concentration from 10% to 30% (vol/vol) stimulated no additional colony formation. However, there was a further augmentation of cell numbers per colony associated with a progressive decrease in the mean megakaryocyte ploidy. Megakaryocyte cultures were harvested after 7, 12, 15, and 19 days of incubation, and these demonstrated that the lower mean ploidy values found at the higher concentrations of aplastic canine serum did not result from delayed endoreduplication. At all aplastic serum concentrations evaluated, there existed a strong correlation between nuclear ploidy and cell diameter. We conclude that both the mitotic and endomitotic events in human megakaryocytopoiesis may be influenced by a factor or factors present in aplastic canine serum. At lower in vitro concentrations, such sera stimulate both mitosis and endomitosis, which promotes the development of megakaryocyte colonies composed of larger cells with a higher mean ploidy. With increasing aplastic serum concentrations, colony formation plateaus and mitosis is favored over endomitosis. This results in colonies composed of more numerous but smaller megakaryocytes with a lower mean ploidy. Our data suggest that the size and extent of polyploidization that can be achieved by a developing megakaryocyte may be influenced by the mitotic prior history of its immediate precursor cell. 相似文献
23.
Human interleukin-5 (IL-5) regulates the production of eosinophils in human bone marrow cultures: comparison and interaction with IL-1, IL-3, IL-6, and GMCSF 总被引:33,自引:1,他引:33
Recombinant human interleukin-5 (rhIL-5), in either liquid or semi- solid cultures, selectively induced eosinophil production from normal human bone marrow, with no activity on other cell lineages. The time course of eosinophil production induced by murine IL-5, rhIL-3, and rh granulocyte-macrophage colony stimulating factor (GMCSF) was similar to rhIL-5. The rate of eosinophil maturation in vitro was independent of the stimulating cytokine, mature eosinophils being produced after 4 to 5 weeks in liquid culture with each of these cytokines. The eosinophils produced in response to each cytokine were morphologically indistinguishable, and had the ultrastructural features of maturity except that the electron-dense material in the granules had not formed into crystalline cores. Neither rhIL-1 nor rhIL-6 alone, or in combination with rhIL-5 or rhIL-3, induced eosinophil differentiation or proliferation under the conditions used. rhIL-3 and rhGMCSF induced more eosinophil colonies than rhIL-5, rhIL-5 had an additive, not synergistic, effect on eosinophil colony production when combined with either rhIL-3 or rhGMCSF, suggesting that rhIL-5 stimulates a smaller and possibly different population of eosinophil progenitors. However, rhIL-5 induced the greatest eosinophil production in liquid cultures, suggesting that although it may act on a smaller population of precursors, it is able to stimulate more proliferative steps than either rhIL-3 or rhGMCSF. 相似文献
24.
Restriction of cell lysis by homologous complement: II. Protection of erythrocytes against lysis by newly activated complement 总被引:1,自引:0,他引:1
Our previous work revealed that homologous complement (C) was ineffective in lysing antibody-sensitized erythrocytes (EA) even at high concentrations. It was also shown that activation of complement on homologous EA resulted in the binding of C9 and the formation of EA bearing complement proteins C1 through C9 (EAC1-9), yet few hemolytic sites were formed. Instead, as shown here, the formation of homologous EAC1-9 caused the cells to become resistant to lysis even by heterologous complement during a second incubation. In contrast, when homologous EAC1-8 were produced by incubating EA with C9-depleted serum, such intermediates were not protected against lysis by heterologous complement during a second incubation. Furthermore, homologous C9 on EAC1-9 was able to reduce the hemolytic efficiency of heterologous complement without blocking C activation and the formation of new C5b-9 complexes. Protection was not modified when homologous EAC1-9 were produced in one step, by incubation of EA with serum, or sequentially by adding C9 to EAC1-8. The minimum number of 9-sites required to confer a protective effect on EAC1-9 was less than 200 per cell. Thus, in addition to its known effect in heterologous cell killing, homologous C9 is capable of protecting homologous cells against inadvertent complement lysis. 相似文献
25.
26.
Peripheral blood mononuclear cells from five patients with essential thrombocythemia (ET) were cultured in vitro to evaluate restricted megakaryocytic (CFU-Meg), myeloid (CFU-GM), and erythroid (BFU-E) progenitor cell development. Varying concentrations of aplastic canine serum served as the source of megakaryocyte colony-stimulating activity, and cultured megakaryocyte ploidy distributions were determined by Feulgen staining and microfluorometry. Megakaryocyte colony growth was strikingly abnormal in all five patients evaluated. Four of the 5 had a marked expansion in the concentration of circulating CFU-Meg and 3 of 4 manifested abnormalities in cultured megakaryocyte colony size (2 unusually large and 1 small). Unstimulated megakaryocyte colony growth was substantially increased in three patients. However, the fraction of megakaryocyte progenitors in cell cycle was near or below normal in all instances. Endomitotic megakaryocyte development was disordered in each of the four ET patients in whom it was evaluable. In normal subjects, mean megakaryocyte ploidy values vary biphasically with aplastic canine serum concentration and peak at 13.2 N following 12 to 15 days of culture. In contrast, day 12 mean ploidy values in cultures from the ET patients remained low at all aplastic canine serum concentrations and reached a maximum averaging only 8.4 N. Three patients were evaluated serially at extended culture durations of up to 21 days. The cultured megakaryocyte ploidy was unchanged during this interval for two of the patients. For the third patient, ploidy increased steadily, reaching abnormally high ploidy values by day 21. Progenitor cell expansion was limited to the megakaryocyte line in three patients. However, two patients had substantial increases in CFU-GM, one of whom also had a marked increase in BFU-E. There was no significant unstimulated colony growth by either CFU-GM or BFU-E. These data indicate that ET is usually characterized by an expansion in the concentration of circulating CFU-Meg in vivo which manifest both disordered replication and endoreduplication in vitro. 相似文献
27.
Objective This study investigates the use of visualization techniques reported between 1996 and 2013 and evaluates innovative approaches to information visualization of electronic health record (EHR) data for knowledge discovery.Methods An electronic literature search was conducted May–July 2013 using MEDLINE and Web of Knowledge, supplemented by citation searching, gray literature searching, and reference list reviews. General search terms were used to assure a comprehensive document search.Results Beginning with 891 articles, the number of articles was reduced by eliminating 191 duplicates. A matrix was developed for categorizing all abstracts and to assist with determining those to be excluded for review. Eighteen articles were included in the final analysis.Discussion Several visualization techniques have been extensively researched. The most mature system is LifeLines and its applications as LifeLines2, EventFlow, and LifeFlow. Initially, research focused on records from a single patient and visualization of the complex data related to one patient. Since 2010, the techniques under investigation are for use with large numbers of patient records and events. Most are linear and allow interaction through scaling and zooming to resize. Color, density, and filter techniques are commonly used for visualization.Conclusions With the burgeoning increase in the amount of electronic healthcare data, the potential for knowledge discovery is significant if data are managed in innovative and effective ways. We identify challenges discovered by previous EHR visualization research, which will help researchers who seek to design and improve visualization techniques. 相似文献
28.
Cytogenetic and molecular analysis in Philadelphia negative CML 总被引:2,自引:0,他引:2
van der Plas DC; Hermans AB; Soekarman D; Smit EM; de Klein A; Smadja N; Alimena G; Goudsmit R; Grosveld G; Hagemeijer A 《Blood》1989,73(4):1038-1044
29.
30.
C M Pratt J B Young A M Wierman R M Borland A A Seals C A Leon A Raizner M A Quinones R Roberts 《The American journal of medicine》1986,80(4):626-632
On the basis of epidemiologic studies, more than 10 million Americans have echocardiographic evidence of mitral valve prolapse. Although ventricular arrhythmias occur frequently (over 50 percent of patients with mitral valve prolapse), they rarely result in sustained ventricular tachycardia or sudden cardiac death. However, a common problem in clinical practice is a patient with mitral valve prolapse and symptomatic complex ventricular arrhythmias refractory or intolerant to both beta blockers and conventional type I antiarrhythmics. These drugs are known to have frequent side effects, toxicity, and proarrhythmic effects. In 17 patients with mitral valve prolapse who presented with symptomatic complex ventricular arrhythmias and who were unresponsive to an average of the three conventional agents, moricizine (Ethmozine) was effective in suppressing 90 percent of ventricular premature depolarizations, 99 percent of nonsustained runs of ventricular tachycardia, as well as all sustained runs of ventricular tachycardia, resulting in abolition of palpitations, dizziness, and syncopal episodes. Its efficacy as well as its low frequency of minor side effects makes it ideal for future consideration in the population with mitral valve prolapse, who are frequently young and may therefore require therapy for many years. 相似文献