Abnormalities in myelopoietic regulatory interactions with acidic isoferritins and lactoferrin in mice infected with Friend virus complex: association with altered expression of Ia antigens on effector and responding cells

The regulation of myelopoiesis was evaluated in B6D2F1 mice inoculated with Friend virus complex (spleen focus-forming virus plus helper virus) or helper virus alone by analyzing acidic isoferritin (AIF) and lactoferrin (LF) interactions with target cells. Under normal conditions, AIF suppresses colony and cluster formation by an Ia- antigen-positive cycling subpopulation of mouse granulocyte-macrophage progenitor cells (CFU-GM). Under the same conditions, the release of AIF-inhibitory activity and granulocyte-macrophage colony stimulatory factors (GM-CSF) from an Ia-antigen-positive subpopulation of monocytes and macrophages is suppressed by LF. Within one to two days after inoculation in vivo with Friend virus complex or helper virus, mouse CFU-GM become insensitive in vitro to suppression by purified human AIF as well as crude mouse AIF, and by four days, bone marrow, spleen, and thymus cells of these mice release much greater quantities of AIF- inhibitory activity than the cells from mice injected with control medium. The Friend virus complex itself has no influence in vitro on CFU-GM from normal mice. In addition, the release of AIF-inhibitory activity from bone marrow, spleen, and resident peritoneal cells and the release of GM-CSF from resident peritoneal cells of mice infected with Friend virus complex are not suppressed by LF. The inability of AIF to suppress colony formation by bone marrow and spleen CFU-GM from mice infected with Friend virus complex is associated with the loss of Ia (I-A subregion) antigens from CFU-GM, even though CFU-GM are in cycle. The nonresponsiveness of bone marrow, spleen, and peritoneal cells from these mice to LF suppression of AIF release and the inability of LF to influence GM-CSF release from peritoneal cells is associated with loss of Ia antigens from these cells. The above abnormalities are similar to the defects noted using cells from patients with leukemia. These results suggest that mice infected with Friend virus complex can serve as a model for investigating abnormalities in cell regulation and their relationships to disease progression.     

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.     

Loss of heterozygosity at locus F13B on chromosome 1q in human medulloblastoma

Medulloblastoma is a primitive neuroectodermal tumor of the cerebellum with poorly understood pathogenesis. Previous studies have reported loss of heterozygosity (LOH) on chromosome arms 17p, 11p and 9q and cytogenetic abnormalities of chromosome 1 in medulloblastoma. We have used the polymerase chain reaction to amplify 10 microsatellites on the short arm and B microsatellites on the long arm of chromosome 1 to assess allelic loss in 22 medulloblastomas. Loss of heterozygosity (LOH) on chromosome 1 was found in 9 cases. Eight medulloblastomas (36%) showed an interstitial LOH on chromosome 1q. The common region of overlap was mapped between DISI604 and DIS237 and included the locus F13B in the chromosomal region 1q31–q32.1. An additional tumor had LOH in a proximal region of 1p, but did not exhibit LOH on 1q. None of the medulloblastomas exhibited LOH of the telomeric portion of chromosome 1p, which has been associated with several other human malignancies. Our data suggest the presence of a putative tumor suppressor gene located near the locus F13B on chromosome arm 1q that appears to be involved in the pathogenesis of medulloblastoma. © 1996 Wiley-Liss, Inc.     

温热治疗肿瘤的基础研究进展

在肿瘤治疗学中,温热治疗是指运用不同方法对恶性肿瘤进行热治疗,他常与放疗、化疗联用,肿瘤的温度常在40-43℃．现综述温热治疗的细胞死亡、体内温热治疗的特征以及温热治疗的效应器等方面的研究进展．     

Prognostic impact of distinct genetic entities in pediatric diffuse glioma WHO-grade II—Report from the German/Swiss SIOP-LGG 2004 cohort

Reports on pediatric low-grade diffuse glioma WHO-grade II (DG2) suggest an impaired survival rate, but lack conclusive results for genetically defined DG2-entities. We analyzed the natural history, treatment and prognosis of DG2 and investigated which genetically defined sub-entities proved unfavorable for survival. Within the prospectively registered, population-based German/Swiss SIOP-LGG 2004 cohort 100 patients (age 0.8-17.8 years, 4% neurofibromatosis [NF1]) were diagnosed with a DG2. Following biopsy (41%) or variable extent of resection (59%), 65 patients received no adjuvant treatment. Radiologic progression or severe neurologic symptoms prompted chemotherapy (n = 18) or radiotherapy (n = 17). Multiple lines of salvage treatment were necessary for 19/35 patients. Five years event-free survival dropped to 0.44, while 5 years overall survival was 0.90 (median observation time 8.3 years). Extensive genetic profiling of 65/100 DG2 identified Histone3-K27M-mutation in 4, IDH1-mutation in 11, BRAF-V600-mutation in 12, KIAA1549-BRAF-fusions in 6 patients, while the remaining 32 tumor tissues did not show alterations of these genes. Progression to malignant glioma occurred in 12 cases of all genetically defined subgroups within a range of 0.5 to 10.8 years, except for tumors carrying KIAA1549-BRAF-fusions. Histone3-K27M-mutant tumors proved uniformly fatal within 0.6 to 2.4 years. The current LGG treatment strategy seems appropriate for all DG2-entities, with the exemption of Histone3-K27M-mutant tumors that require a HGG-related treatment strategy. Our data confirm the importance to genetically define pediatric low-grade diffuse gliomas for proper treatment decisions and risk assessment.     

Biology and grading of pleomorphic xanthoastrocytoma—what have we learned about it?

Pleomorphic xanthoastrocytoma (PXA) is a rare astrocytoma predominantly affecting children and young adults. We performed comprehensive genomic characterization on a cohort of 67 patients with histologically defined PXA (n = 53, 79%) or anaplastic PXA (A‐PXA, n = 14, 21%), including copy number analysis (ThermoFisher Oncoscan, n = 67), methylation profiling (Illumina EPIC array, n = 43) and targeted next generation sequencing (n = 32). The most frequent alterations were CDKN2A/B deletion (n = 63; 94%) and BRAF p.V600E (n = 51, 76.1%). In 7 BRAF p.V600 wild‐type cases, alternative driver alterations were identified involving BRAF, RAF1 and NF1. Downstream phosphorylation of ERK kinase was uniformly present. Additional pathogenic alterations were rare, with TERT, ATRX and TP53 mutations identified in a small number of tumors, predominantly A‐PXA. Methylation‐based classification of 46 cases utilizing a comprehensive reference tumor allowed assignment to the PXA methylation class in 40 cases. A minority grouped with the methylation classes of ganglioglioma or pilocytic astrocytoma (n = 2), anaplastic pilocytic astrocytoma (n = 2) or control tissues (n = 2). In 9 cases, tissue was available from matched primary and recurrent tumors, including 8 with anaplastic transformation. At recurrence, two tumors acquired TERT promoter mutations and the majority demonstrated additional non‐recurrent copy number alterations. Methylation class was preserved at recurrence. For 62 patients (92.5%), clinical follow‐up data were available (median follow‐up, 5.4 years). Overall survival was significantly different between PXA and A‐PXA (5‐year OS 80.8% vs. 47.6%; P = 0.0009) but not progression‐free survival (5‐year PFS 59.9% vs. 39.8%; P = 0.05). WHO grade remained a strong predictor of overall survival when limited to 38 cases defined as PXA by methylation‐based classification. Our data confirm the importance of WHO grading in histologically and epigenetically defined PXA. Methylation‐based classification may be helpful in cases with ambiguous morphology, but is largely confirmatory in PXA with well‐defined morphology.     

Purified verotoxins of Escherichia coli O157:H7 decrease prostacyclin synthesis by endothelial cells

Two immunologically distinct verotoxins purified from Escherichia coli C600, lysogenized with distinct temperate phages from E. coli strain 933 of serotype O157:H7, were compared by SDS-PAGE and different biological assays. The two toxins termed verotoxin 1 (VT1) and verotoxin 2 (VT2) differing in molecular weight exhibited similar biological activities. Both preparations were toxic for HeLa cells and lethal for mice. Epidemiological evidence of verotoxinogenesis in some cases of hemolytic-uremic syndrome (HUS) and the recent observations of inadequate prostacyclin production by endothelial cells associated with HUS prompted us to study the effect of purified verotoxins on prostacyclin synthesis in rat aortic tissue. Our results demonstrate a significant reduction of prostacyclin by both toxins at picomolar levels. The suppression of prostacyclin release by a lower concentration of VT2 as compared with VT1 reflects the relative potencies of these toxins in HeLa cell toxicity and mouse lethality. The results suggest an effect of verotoxins on endothelial cells and support the concept of these toxins as virulence factors in E. coli.