Administration of pegylated recombinant human megakaryocyte growth and development factor to humans stimulates the production of functional platelets that show no evidence of in vivo activation

This report describes the effect of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on platelet production and platelet function in humans. Subjects with advanced solid tumors received PEG-rHuMGDF daily for up to 10 days. There was no increase in circulating platelet count at doses of 0.03 or 0.1 microgram/kg/d by day 12 of study. At doses of 0.3 and 1.0 microgram/kg/d there was a threefold median increase (maximum 10-fold) in platelet count by day 16. The platelets produced in vivo in response to PEG-rHuMGDF showed unchanged aggregation and adenosine triphosphate (ATP)-release responses in in vitro assays. Tests included aggregation and release of ATP in response to adenosine diphosphate (ADP) (10, 5, 2.5, and 1.25 mumol/L), collagen (2 micrograms/mL), thrombin-receptor agonist peptide (TRAP, 10 mumol/L) and ristocetin (1.5 mg/mL). Administration of aspirin to an individual with platelet count of 1,771 x 10(3)/L resulted in the typical aspirin-induced ablation of the normal aggregation and ATP-release response to stimulation with arachidonic acid (0.5 mg/mL), collagen, and ADP (2.5 and 1.25 mumol/L). There was no change in the expression of the platelet-surface activation marker CD62P (P-selectin) nor induction of the fibrinogen binding site on glycoprotein IIb/IIIa as reported by the monoclonal antibody, D3GP3. An elevation of reticulated platelets was evident after 3 days of treatment with PEG-rHuMGDF and preceded the increase in circulating platelet count by 5 to 8 days; this reflected the production of new platelets in response to PEG-rHuMGDF. At later time points, the mean platelet volume (MPV) decreased in a manner inversely proportional to the platelet count. Levels of plasma glycocalicin, a measure of platelet turnover, rose 3 days after the initial increase in the peripheral platelet count. The level of plasma glycocalicin was proportional to the total platelet mass, suggesting that platelets generated in response to PEG-rHuMGDF were not more actively destroyed. Thus, the administration of PEG-rHuMGDF, to humans, increased the circulating platelet count and resulted in fully functional platelets, which showed no detectable increase in reactivity nor alteration in activation status.     

B220- bone marrow progenitor cells from New Zealand black autoimmune mice exhibit an age-associated decline in Pre-B and B-cell generation

New Zealand Black (NZB) autoimmune mice exhibit progressive, age- dependent reduction in bone marrow pre-B cells. To ascertain the capacity of NZB bone marrow B220- cells to generate pre-B cells in a supportive environment, B-lineage (B220+) cell-depleted and T-cell- depleted bone marrow cells from NZB mice at 1 to 3, 6, and 10 to 11 months of age were adoptively transferred into irradiated (200R) C.B17 severe combined immunodeficient (SCID) mice. Bone marrow pre-B cells (sIgM- CD43[S7]- B220+) were assessed 3 and 10 weeks posttransfer. Pre- B cells and B cells were reconstituted in SCID recipients of older NZB progenitor cells by 10 weeks posttransplant, in contrast to the very low numbers of pre-B cells present in the donor bone marrow. However, B220- bone marrow progenitor cells from greater than 10-month-old NZB donors were deficient in the reconstitution of both pre-B and B cells in SCID recipients at 3 weeks post-transfer. This reflected a slower kinetics of repopulation, because older NZB-->SCID recipients had numbers of both pre-B and B cells similar to recipients of young NZB progenitor cells by 10 weeks posttransplant. Adoptive transfer of equal mixtures of BALB/c and older NZB bone marrow B220- progenitor cells into irradiated C.B17 SCID recipients failed to demonstrate active suppression. These results suggest that, with age, NZB bone marrow has reduced numbers and/or function of early B220- B-lineage progenitors. Consistent with this hypothesis, B220- bone marrow cells from older NZB mice were deficient in progenitors capable of yielding interleukin-7 (IL-7) responsive pre-B cells in vitro on stimulation with the pre-B- cell potentiating factor, insulin-like growth factor 1 (IGF-1).     

鸟氨酸脱羧酶的生理病理特点及其药物研究概况

鸟氨酸脱羧酶(ornithinedecarboxylase,ODC)是多胺代谢中的关键酶,广泛存在于人体和动物各组织细胞内,其中对肠细胞的增生、移行和分化起重要作用.机体调节因素比较复杂.在黏膜损伤性疾病及某些癌前病变等细胞大量增生的病理情况下ODC的表达发生改变,可以作为这些疾病分期、预后及药物作用靶点或疗效的指标.寻找对ODC有作用的药物对于治疗其相关疾病是非常有意义的.     

Thrombospondin mediates the cytoadherence of Plasmodium falciparum- infected red cells to vascular endothelium in shear flow conditions

Cerebral malaria is thought to involve specific attachment of Plasmodium falciparum-infected knobby red cells to venular endothelium. The nature of surface ligands on host endothelial cells that may mediate cytoadherence is poorly understood. We have investigated the effects of soluble thrombospondin, rabbit antiserum raised against thrombospondin, and human immune serum on cytoadherence of parasitized erythrocytes in ex vivo mesocecum vasculature. Preincubation of infected red cells with soluble thrombospondin or human immune serum inhibits binding of infected red cells to rat venular endothelium. Infusion of the microcirculatory preparation with rabbit antithrombospondin antibodies before perfusion of parasitized erythrocytes also resulted in decreased cytoadherence. In addition, incubation of infected cells with human immune sera obtained from malaria patients significantly inhibited the observed cytoadherence. Our results indicate that thrombospondin mediates binding of infected red cells to venular endothelium and may thus be involved in the pathogenesis of cerebral malaria.     

Blood donation leads to a decrease in natural killer cell activity: a study in normal blood donors and cancer patients

Transfusion-induced immunosuppression has long been known to be beneficial for organ transplantation patients, but recent retrospective studies suggest that blood transfusions may be detrimental for patients with cancer. If autologous blood is used to avoid immunosuppression, the assumption is that the procedure, involving blood donation, is immunologically neutral. In the present study, this assumption was evaluated by monitoring 33 normal blood donors and 16 colorectal cancer patients before and after donation of 1 (500 mL) and 2 units of blood, respectively. The cancer patients belonged to the autologous arm of a randomized trial in which the effects of allogeneic versus autologous blood on cancer prognosis were studied. The patients donated 2 units of blood with an interval of 3 to 4 days between donations. Flow cytometric analysis revealed that blood donation by normal donors and cancer patients had no effect on the proportion of B, T, and natural killer (NK) cells. Only the total number of lymphocytes was significantly decreased in the normal donors on Day 12 after donation. Blood donation had no significant effect on T-cell function assessed by phytohemagglutinin stimulation in normal donors or in cancer patients donating 2 units of blood. A significant depression of NK cell function (88% and 74% of predonation levels) was observed in normal donors on Days 2 and 5 after donation; on Day 12, the activity was again normal. Colorectal cancer patients had a significantly depressed NK cell activity (54% of predonation activity) on Day 12 after the first donation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Immune responses to Aspergillus antigen in IL‐4‐/‐ mice and the effect of eosinophil ablation

BACKGROUND: Exposure to Aspergillus fumigatus allergens results in enhanced total serum IgE and peripheral blood eosinophils in mice. The associated pulmonary inflammation and immunologic responses are comparable to those detected in human allergic bronchopulmonary aspergillosis. Allergen-induced cytokines are thought to regulate the inflammatory and immune responses in these animals. METHODS: In the present study, we exposed C57BL/6 and BALB/c mice to A. fumigatus antigen. Both wild-type and IL-4 knockout phenotypes of animals of both strains were used. Some animals were also treated with anti-IL-5 or anti-IFN-gamma. Total serum IgE, Aspergillus species IgG subclass, peripheral blood eosinophils, and lung histology were studied. RESULTS: The results demonstrate similar lung inflammation in all wild-type and IL-4-/- animals exposed to A. fumigatus antigen. Similarly, in spite of the diverse immune response produced by the anticytokine treatment, no major differences were detected among any of the animal groups studied. CONCLUSIONS: It can be concluded that A. fumigatus exposure in an immunologically unaltered host is predominantly of a Th2 type, and that depletion of the Th2 cytokine leads to a similar lung inflammation but with a characteristic Th1 response, suggesting that the pathogenesis of allergic aspergillosis is the result of multiple induction pathways.     

Overexpression of Pim-1 during progression of prostatic adenocarcinoma

AIMS: Pim-1 is a serine/threonine kinase that has been shown to play an integral role in the development of a number of human cancers, such as haematolymphoid malignancies. Recently, evidence has shown Pim-1 to be important in prostatic carcinogenesis. In order to further our understanding of its role in prostate cancer, we investigated Pim-1 expression in normal, premalignant, and malignant prostate tissue. METHODS: Using immunohistochemistry, Pim-1 expression was analysed in prostate tissue from 120 radical prostatectomy specimens. In each case, Pim-1 staining was evaluated in benign prostatic epithelium, high grade prostatic intraepithelial neoplasia (PIN), and prostatic adenocarcinoma. The number of positively staining cells was estimated, and the intensity of staining was scored on a scale of 0 to 3+. RESULTS: Pim-1 immunoreactivity was identified in 120 cases (100%) of adenocarcinoma, 120 cases (100%) of high grade PIN, and 62 cases (52%) of benign glands. The number of cells staining in benign epithelium (mean 34%) was much lower than that in high grade PIN (mean 80%; p<0.0001) or adenocarcinoma (mean, 84%; p<0.0001). There was no significant difference between high grade PIN and adenocarcinoma in the percentage of cells staining positively for Pim-1 (p = 0.34). The staining intensity for Pim-1 was significantly lower in benign prostatic epithelium than in PIN and adenocarcinoma (p<0.001). There was no statistically significant correlation between the level of Pim-1 expression and Gleason score, patient age, tumour stage, lymph node metastasis, perineural invasion, vascular invasion, surgical margin status, extraprostatic extension, or seminal vesicle invasion. CONCLUSIONS: Pim-1 expression is elevated in PIN and prostatic adenocarcinoma compared with benign prostatic epithelium. This finding suggests that upregulation of Pim-1 may play a role in prostatic neoplasia.