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排序方式: 共有269条查询结果,搜索用时 15 毫秒
61.
The use of peripheral blood progenitor cells (PBPC) to reconstitute hematopoiesis after high-dose chemoradiotherapy is now commonplace in the treatment of malignancies. Attempts to characterize these cells have concentrated primarily on their phenotype and their content of clonogenic colony-forming cells (CFC). We have used a plastic-adherent delta (P delta) assay system to evaluate the quantity and quality of more primitive cells in addition to the conventional measurements of CFC and CD34-positive cells. The leukapheresis products from 20 patients mobilized using cyclophosphamide (Cy) and granulocyte colony- stimulating factor (G-CSF) were examined for progenitor cell content. The mean number of mononuclear cells (MNC), colony-forming units- granulocyte/macrophage (CFU-GM), and CD34-positive cells from two leukaphereses per patients were 7.9 x 10(8)/kg, 47.3 x 10(4)/kg, and 10.5 x 10(6)/kg, respectively. The mean number of P delta progenitors was 9.3 x 10(4)/kg. Limiting dilution analyses showed the frequency of P delta progenitors in PBPC to be between 1 and 5.3 per 10(5) MNC and that each P delta progenitor has the proliferative capability to generate an overall mean of 4.5 CFU-GM. Of the 20 patients, 16 underwent autografting with PBPC alone. Fifteen patients engrafted neutrophils and platelets within 16 days. One patient had delayed engraftment associated with inadequate etoposide clearance. Statistical analysis showed a strong correlation between numbers of CFU-GM and CD34 positivity. The numbers of plastic-adherent P delta progenitor cells did not correlate with CFU-GM or CD34-positive cells. We conclude that the plastic-adherent P delta progenitor cell assay is capable of measuring primitive hematopoietic cells and that it may be useful for the investigation of primitive progenitors in PBPC harvests. 相似文献
62.
Ning Zhang Chen Chen Mary AS Melo Yu-Xing Bai Lei Cheng Hockin HK Xu 《International journal of oral science》2015,7(2):103-109
Secondary caries due to biofilm acids is a primary cause of dental composite restoration failure.To date,there have been no reports of dental composites that can repel protein adsorption and inhibit bacteria attachment.The objectives of this study were to develop a protein-repellent dental composite by incorporating 2-methacryloyloxyethyl phosphorylcholine(MPC) and to investigate for the first time the effects of MPC mass fraction on protein adsorption,bacteria attachment,biofilm growth,and mechanical properties.Composites were synthesized with 0(control),0.75%,1.5%,2.25%,3%,4.5%and 6%of MPC by mass.A commercial composite was also tested as a control.Mechanical properties were measured in three-point flexure.Protein adsorption onto the composite was determined by the microbicinchoninic acid method.A human saliva microcosm biofilm model was used.Early attachment at 4 h,biofilm at 2 days,live/dead staining and colony-forming units(CFUs) of biofilms grown on the composites were investigated.Composites with MPC of up to 3%had mechanical properties similar to those without MPC and those of the commercial control,whereas 4.5%and 6%MPC decreased the mechanical properties(P<0.05).Increasing MPC from 0 to 3%reduced the protein adsorption on composites(P<0.05).The composite with 3%MPC had protein adsorption that was 1/12 that of the control(P<0.05).Oral bacteria early attachment and biofilm growth were also greatly reduced on the composite with 3%MPC,compared to the control(P<0.05).In conclusion,incorporation of MPC into composites at 3%greatly reduced protein adsorption,bacteria attachment and biofilm CFUs,without compromising mechanical properties.Protein-repellent composites could help to repel bacteria attachment and plaque build-up to reduce secondary caries.The protein-repellent method might be applicable to other dental materials. 相似文献
63.
Verdonck LF; Dekker AW; de Gast GC; van Kempen ML; Lokhorst HM; Nieuwenhuis HK 《Blood》1994,83(10):3090-3096
Despite prophylaxis with immunosuppressive drugs, severe acute graft- versus-host disease (GVHD) remains a major cause of morbidity and mortality in patients transplanted with unmodified bone marrow (BM) grafts from HLA-identical siblings. Although T-cell depletion of the BM graft has evolved as the most effective method to prevent severe acute GVHD, this beneficial effect is counterbalanced by an increased rate of graft failure and relapse of the disease. To find an approach to T-cell depletion that may avoid these extreme risks, we gave BM recipients a fixed low number of 1 x 10(5) donor T cells per kilogram of recipient's body weight in the graft. This corresponds with 99% T-cell depletion and is achieved by the addition of T cells to the graft that was previously depleted of T cells. A total of 70 patients with hematologic malignancies or aplastic anemia, including 40 patients with standard- risk leukemias, received BM grafts, depleted of T cells according to this approach, from HLA-identical siblings. The preparative regimen consisted of cyclophosphamide and total body irradiation. The patients also received a short course of cyclosporine posttransplant. Graft failure did not occur. Acute GVHD, only grade I or II, was seen in 70% of the patients and was limited to the skin in all patients. Chronic GVHD occurred in 31% of the patients and, with the exception of 1 patient, was limited to the skin as well. Relapse occurred in 3 of 40 (8%) patients with standard-risk leukemias, resulting in a projected survival at 5 years of 80%. Patients with standard-risk diseases had a procedure-related mortality of 11%. Quality of life, determined 1 year after BM transplant, was good in almost all patients with standard-risk diseases. Thus, this approach of T-cell depletion may be an approach that avoids the development of severe acute and chronic GVHD without damaging the function or antileukemic effect of the graft and that has a low transplant-related morbidity and mortality. 相似文献
64.
Interleukin-7 (IL-7) has been shown to be a critical factor in murine lymphoid development. It stimulates pre-B cells to divide in the absence of stroma cells and it is an important growth regulator of immature and mature T cells. IL-7 has been shown to synergize with stem cell factor (SCF) to provide a potent growth stimulus for pre-B cells. However, the combined effects of IL-7 and SCF on murine primitive hematopoietic cells in vitro have not been established. In the present study, the effects of recombinant rat (rr) SCF and recombinant human (rh) IL-7 on primitive murine bone marrow progenitors (Lin-Sca1+) were investigated in single-cell cloning experiments. rhIL-7 alone had no proliferative effect on Lin-Sca1+ cells, but in a dose-dependent manner directly enhanced rrSCF-induced colony formation, with an average increase in colony numbers of 2.7-fold. Interestingly, the cells formed in response to SCF and IL-7 were predominantly mature granulocytes. Thus, SCF and IL-7 synergize to stimulate early myelopoiesis in vitro. 相似文献
65.
Platelet adhesion to collagen type IV under flow conditions 总被引:3,自引:2,他引:3
Henrita van Zanten G; Saelman EU; Schut-Hese KM; Wu YP; Slootweg PJ; Nieuwenhuis HK; de Groot PG; Sixma JJ 《Blood》1996,88(10):3862-3871
Collagen type IV is a sheet-forming collagen and a major constituent of the vessel wall. To find out which conditions are important for platelet adhesion to collagen type IV, we performed perfusion studies with anticoagulated blood in parallel plate perfusion chambers. The role of divalent cations was investigated by using plasmas with variable concentrations of Mg2+ and Ca2+ ions. When Mg2+ concentration was decreased from 2.00 mmol/L to 0.25 mmol/L at a fixed Ca2+ concentration of 1.25 mmol/L, platelet coverage on the collagen type IV surface decreased from 22.8% +/- 1.8% (n = 4) to 4.6% +/- 0.6% (n = 4) at a shear rate of 1,600 s-1. Also, platelet aggregate formation on collagen type IV was strongly impaired. A monoclonal antibody against the glycoprotein (Gp) Ib receptor and von Willebrand factor (vWF)- depleted plasma reduced the platelet coverage to collagen type IV to, respectively, 10% and 45% of the control value. Electron microscopy showed that vWF was only present between platelets and between the platelet and the collagen type IV surface, but did not bind elsewhere to collagen type IV. These data indicate that collagen type IV is a reactive collagen for platelets. Differences in physiologic plasma magnesium concentrations may in part explain the differences in platelet reactivity to collagen type IV between individuals, and perhaps contribute to differences in the risk for thrombosis. 相似文献
66.
Platelet adhesion to collagen and endothelial cell matrix under flow conditions is not dependent on platelet glycoprotein IV 总被引:3,自引:1,他引:3
Platelet membrane glycoprotein IV (GPIV) is a cell-surface glycoprotein that has been proposed as a receptor for collagen. Recently, it has been shown that platelets with the Naka-negative phenotype lack GPIV on their surface, whereas donors with this phenotype are healthy and do not suffer from hematologic disorders. In this study, we compared Naka- negative platelets with normal platelets in adhesion to collagen types I, III, IV, and V and the extracellular matrix of endothelial cells (ECM) under static and flow conditions. No differences in platelet adhesion and subsequent aggregate formation on the collagens types I, III, and IV were observed under static and flow conditions. Adhesion of both homozygous and heterozygous Naka-negative platelets to collagen type V was strongly reduced under static conditions. Collagen type V was not adhesive under flow conditions. No difference in platelet adhesion to ECM was observed, which suggests that GPIV is not important in adhesion to subendothelium, for which ECM may serve as a model. These results indicate that GPIV is not a functional receptor for collagen under flow conditions. 相似文献
67.
Purpose
Shoulder arthroplasties are increasingly performed, but data on periprosthetic joint infections (PJI) in this anatomical position are limited. We retrospectively investigated the characteristics and outcome of shoulder PJI after primary arthroplasty from 1998 to 2010 in a single centre.Methods
Periprosthetic joint infection was defined as periprosthetic purulence, presence of sinus tract or microbial growth. A Kaplan–Meier survival method was used to estimate relapse-free survival of prosthesis.Results
From 1,571 primary shoulder prostheses, we evaluated 16 patients with a PJI at different stages, i.e, early (n = 4), delayed (n = 6) and late (n = 6) infections. The median patient age was 67 (range 53–86) years, and 69 % were females. The most commonly isolated microorganism was Propionibacterium acnes in 38 % of patients (monobacterial in four and polymicrobial in two patients). In 14 of the 16 patients, surgical interventions consisting of debridement and implant retention (6 patients), exchange (7) and explantation (1) were performed. Four patients had a relapse of infection with P. acnes (n = 3) or Bacteroides fragilis (n = 1). The relapse-free survival of the prosthesis was 75 % (95 % confidence interval 46–90 %) after 1 and 2 years, 100 % in six patients following the treatment algorithm for hip and knee PJI and 60 % in 10 patients not followed up. All but one of the relapses were previously treated without exchange of the prosthesis.Conclusions
As recommended for hip and knee PJI, we suggest treating shoulder PJI with a low-grade infection by microorganisms such as P. acnes with an exchange of the prosthesis. Cohort studies are needed to verify our results. 相似文献68.
HK Ulatowska G Streit Olness MW Keebler KE Goins 《International journal of speech-language pathology》2013,15(1):3-14
This investigation explores the discourse devices associated with high-quality personal narratives. The study examined normative characteristics of 11 high-quality personal narratives of a frightening experience identified (from a larger set of 72 narratives) for their effectiveness in engaging the audience. Lay ratings and an ethnographic interview with seven of the excellent storytellers further characterized the stories and validated their selection. Narratives of both African Americans and Caucasians were represented, and were similar in nature. The excellent narratives were longer, conveyed more fearful topics, and were more dramatic than average narratives. Drama was achieved through direct speech, prosodic shifts, voice changes, inclusion of multiple characters, repetition, and syntactic and semantic parallelism. Illustrative narrative excerpts are provided. This study illustrates the potential in pairing holistic and analytical approaches to narrative analysis. 相似文献
69.
HK Blomquist 《Acta paediatrica (Oslo, Norway : 1992)》2000,89(S434):24-32
Literature concerning the role of the Child Health Services in the identification of children with possible Attention Deficit Hyperactivity Disorder/Deficits in Attention, Motor Control and Perception (ADHD/DAMP) is summarized in order to establish a background for evaluation, discussion and conclusion. 相似文献
70.
E Pesonen J Viikari L Räsänen T Moilanen J Turtinen HK Åkerblom 《Acta paediatrica (Oslo, Norway : 1992)》1994,83(4):378-382
In the Finnish multicentre study of cardiovascular risk in young Finns in 1980, 1983 and 1986, 2429, 2052 and 1841 9 to 18-year-old children and adolescents participated. In 1980, subjects of eastern origin living in the west had, despite their western diet, higher serum cholesterol concentrations than subjects both residing in and originating from the west. In males, eastern origin increased the eastlwest difference in serum cholesterol concentrations. Between 1980 and 1986 the mean serum total cholesterol of the study cohorts decreased by 5.5% and simultaneously the east/west differences in serum cholesterol concentrations disappeared in boys. The study suggests that genetic background is a separate factor determining serum total cholesterol level, but with declining serum cholesterol concentrations the effect of the genetic factor does not become manifest. 相似文献