Biomedical subjects

Yizhou Zheng

Publications and source records attributed to Yizhou Zheng.

5 recordsLinked to original sources

PubMed2006

Immunosuppressive therapy for acquired severe aplastic anemia (SAA): a prospective comparison of four different regimens.

OBJECTIVE: This study was designed to investigate four different immunosuppressive therapy (IST) regimens as treatment of acquired severe aplastic anemia (SAA). PATIENTS AND METHODS: 142 consecutive SAA patients were randomized to receive one of the following IST regimens: equine anti-human thymocyte immunoglobulin (E-ATG) alone (IST regimen I); E-ATG and cyclosporine A (CSA) (IST regimen II); E-ATG, CSA plus recombinant human granulocyte-macrophage colony-stimulating factor (rhuGM-CSF) and rhu erythropoietin (rhuEPO) (IST regimen III); or rabbit ATG (ATG-F), CSA, rhuGM-CSF, and rhuEPO (IST regimen IV). No repeated courses of E-ATG or ATG-F were given for nonresponders. All patients also received stanozolol or testosteron propionate. RESULTS: The overall response rate to IST regimen I was 58%. The response to IST regimen II (79%) was significantly higher (p = 0.04), more rapid and complete than after IST regimen I. The response rate to IST regimen IV (53%) was significantly lower than that of IST regimen III (73%, p = 0.039). The additional use of growth factors did not reduce early deaths and did not accelerate hematopoietic recovery after IST. Of the 142 patients enrolled in this trial, 92 (65%) are alive at a median follow-up time of 102 months (range, 54-166 months). The 5-year actuarial survival for IST regimens I, II, III, and IV was 58%, 81%, 80%, and 66%, respectively. CONCLUSION: The combination of E-ATG and CSA remains the best combination for the treatment of SAA patients, producing a survival advantage at 5 years. The addition of growth factors did not improve these results. Rabbit ATG-F appeared less effective than E-ATG.

Adolescent↗

PubMed2005

Modified minimal model using a single-step fitting process for the intravenous glucose tolerance test in Type 2 diabetes and healthy humans.

The classical minimal model with single compartment was modified by the assumption that the insulin decay rate is not always a first-order process, and a mathematical function for describing the insulin infusion rate is introduced. The modified model was used to study four sets of published data including healthy humans and Type 2 diabetes with different types of insulin infusion rates. The single-step fitting process took the glucose-insulin system as a dynamic integrated physiological system and generated the real optimized model parameters from the experimental data using the modified model. It also avoided the errors from the interpolation or extrapolation for taking measured insulin points as inputs, which were mostly employed in publications when using the single or multi-compartments minimal model. The averaged R(2) value between measured and calculated plasma concentrations for these four cases is 0.977, which indicates excellent agreement.

Blood Glucose↗

PubMed2005

SCID-repopulating activity of human umbilical cord blood-derived hematopoietic stem and/or progenitor cells in a nonobese diabetic/Shi-SCID mice serial xenotransplantation model and immune cell activities in vitro: a comparative study of the filter method and the hydroxyethyl starch method.

BACKGROUND: A novel filter system was developed for umbilical cord blood (UCB) volume reduction. The aim of this study was to compare the functions of cryopreserved UCB cells processed by the filter and by the hydroxyethyl starch (HES) sedimentation method from the aspect of the graft quality. STUDY DESIGN AND METHODS: UCB specimens were divided into two portions, processed in parallel by the filter or HES, and then cryopreserved in the clinical setting. The thawed UCB specimens containing 1 x 10(5) CD34+ cells were injected into nonobese diabetic/Shi-SCID mice, and the engraftment capacity in primary and secondary transplants was assessed. The functions of natural killer (NK) cells and monocyte-derived dendritic cells (DCs) were also assayed in vitro. RESULTS: The percentage of recovery of CD34+ cells by both methods was equivalent. In the marrow of the primary transplant recipients, the percentage of hCD45+ cells in the filter group and HES group was 58.2 +/- 31.6 and 46.5 +/- 28.4 percent, respectively (p = 0.016). The engraftment capacity and multilineage differentiation in the secondary transplantations were equal in both groups. The cytotoxic activity of the NK cells and phagocytosis activity of the DCs from both the groups were similar. CONCLUSION: The filter yielded a desirable percentage of recovery of hematopoietic cells with engraftment ability in the clinical setting. Thus, it is considered that the filter system may be useful for UCB banking for cord blood transplantation.

Animals↗

PubMed2003

Ex vivo manipulation of umbilical cord blood-derived hematopoietic stem/progenitor cells with recombinant human stem cell factor can up-regulate levels of homing-essential molecules to increase their transmigratory potential.

OBJECTIVE: The cause of delayed hematopoietic reconstitution after umbilical cord blood transplantation (UCBT) remains controversial. We hypothesized that hematopoietic stem/progenitor cells (HS/PCs) from UCB have some defects of the homing-related molecules responsible for their slow engraftment. MATERIALS AND METHODS: A homing-related molecule repertoire expressed on HS/PCs from fresh and cryopreserved UCB, mobilized peripheral blood (mPB), and bone marrow (BM) were compared using sensitive, four-color fluorescence-activated cell sorting analysis. Purified CD34+ cells were subjected to ex vivo transmigration through double-coated transwell filter inserts, and an in vivo homing assay was performed in xenotransplanted NOD/SCID mice. RESULTS: UCB-derived CD34(bright) cells expressed significantly lower levels of CD49e, CD49f, and CXCR-4 than their mPB and BM counterparts. CD34+ cells from UCB (and BM) exhibited significantly lower ex vivo transmigration than those from mPB, which were largely blocked by neutralizing antibodies to CD49e or CD49f. Recombinant human tumor necrosis factor-alpha treatment enhanced ex vivo transmigration of CD34+ cells from UCB and BM by inducing expression of the matrix metalloproteinases MMP-2/MMP-9. Short-term treatment of UCB-derived CD34+ cells with rHu-stem cell factor (rHuSCF) up-regulated levels of the homing-related molecules with their increased ex vivo transmigratory and in vivo homing potential. CONCLUSION: Our results indicate that disadvantageous transmigratory behavior of HS/PCs from UCB, which might partly explain the delayed reconstitution after UCBT, can be reversed by ex vivo manipulation with rHuSCF.

Animals↗

PubMed2003

Wash-out of DMSO does not improve the speed of engraftment of cord blood transplantation: follow-up of 46 adult patients with units shipped from a single cord blood bank.

BACKGROUND: Prolonged periods of marrow hypoplasia have been a problem in cord blood transplantation. DMSO is thought to produce osmotic shock to the progenitors when the thawed cells are infused into the patients. To solve this problem, a 2x dilution method originally developed in the New York Blood Center showed earlier myeloid engraftment,1 although follow-up clinical studies have not performed. STUDY DESIGN AND METHODS: To clarify the influence of the removal of DMSO by this method on the speed of engraftment in unrelated cord blood transplantation, 46 adult patients with cord blood units processed by the Tokyo Cord Blood Bank from September 1998 to March 31, 2002 were studied. Twenty-four patients received 2.6 +/- 0.71 x 10(7) nucleated cells per kg without washing (nonwashed group), while 22 patients were received 2.7 +/- 0.52 x 10(7) nucleated cells per kg after 2x dilution washing (washed group). RESULTS: The cumulative incidence of engraftment was not significantly different between the two groups. Median neutrophil recovery (>/=5 x 10(9)/L) in the nonwashed and washed groups was 26 and 25 days, respectively, and the median platelet recovery (>/=20 x 10(9)/L) in patients with myeloid engraftment was 44 and 40 days, respectively (NS). On the other hand, the doses of CFCs and CD34+ cells showed the influence on myeloid and platelet recovery. CONCLUSION: A 2x dilution after thawing cord blood did not result in the improvement of myeloid engraftment speed.

Adolescent↗