血管紧张素原基因5''''端启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性

目的分析血管紧张素原基因启动子区A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压的相关性.方法实验于2005-08/2006-01在北京华大实验室完成.选取对象均为生活在内蒙古乌拉特后旗的蒙古族牧民,三代血亲内无其他民族.采用基因测序技术对内蒙古蒙古族人群中107例原发性高血压患者和108例正常对照者进行A-20C和A-6G基因分型,观察高血压组和正常对照组不同基因型的分布和等位基因频率的差异.结果①两组受试者在性别、年龄及吸烟、饮酒、体质量指数和l临床化验检查指标有较好的匹配(P均＞0.05).②两组血管紧张素原基因A-20C位点AA,AC,CC基因型频率比较差异无显著性意义(高血压组分别为0.51,0.29,0.20;正常对照组分别为0.49,0.28,0.23,x2=0.395,P=0.529).A,C等位基因频率比较差异无显著性意义(高血压组分别为0.65,0.35;正常对照组分别为0.63,0.37,x2=0.015,P=0.904).③两组血管紧张素原基因A-6G位点AA,AG,GG基因型频率比较差异无显著性意义(高血压组分别为0.50,0.33,0.17;正常对照组分别为0.55,0.34,0.11,x2=1.924,P=0.165).A,G等位基因频率比较差异无显著性意义(高血压组分别为0.66,0.34;正常对照组分别为0.72,0.28,x2=1.728,P=0.189).④高血压组协同存在血管紧张素原基因A-20C基因型CC时,血管紧张素原基因A-6G基因型GG频率稍高于正常对照组,但差异无显著性意义(x2=2.395,P=0.122,OR=7.52,95%CI 0.014～1.250),高血压组G等位基因明显高于正常对照组(分别为0.37,0.22,x2=4.658,P=0.034),携带该等位基因的蒙古族人群发生原发性高血压的相对危险度升高(OR=2.80,95%CI.087～7.271).结论血管紧张素原基因A-20C和A-6G单核苷酸多态性与蒙古族人群原发性高血压相关,并可能具有协同作用.     

Distribution of G-protein-coupled receptor (GPCR)135 binding sites and receptor mRNA in the rat brain suggests a role for relaxin-3 in neuroendocrine and sensory processing

G-protein-coupled receptor 135 (GPCR135), a former orphan GPCR also known as SALPR, has recently been shown to be modulated by relaxin-3 (R3). In addition to GPCR135, R3 has been shown to be an agonist for GPCR142 (which is a pseudogene in the rat) and to activate LGR7, which is primarily the receptor for relaxin-1/2. The interaction of R3 with LGR7 has confounded the autoradiographic study of the GPCR135 distribution in the rat CNS due to significant expression of LGR7 in the brain. R3/I5, a chimera of the B-chain of R3 bonded to the A-chain of INSL-5, is a specific GPCR135 agonist which is highly selective for GPCR135 over LGR7. [(125)I]R3/I5 specifically binds to sites on rat brain sections with a pharmacology matching results from membrane preparations of recombinant GPCR135 receptors. Autoradiographic studies show the GPCR135 receptor density is most prominent in areas such as the olfactory bulb, sensory cortex, amygdala, thalamus, paraventricular nucleus, supraoptic nucleus, inferior and superior colliculus. The GPCR135 mRNA distribution generally overlaps the pattern of GPCR135 binding sites shown by autoradiography using [(125)I]R3/I5. The nucleus incertus, which has been implicated in the extrapituitary actions of corticotropin-releasing hormone, is the primary source of R3 in the rat central nervous system and expresses GPCR135 receptors. These binding autoradiography and in situ hybridization data suggest that GPCR135 plays an important role in the central processing of sensory signals in rats, are consistent with a putative role for R3/GPCR135 as modulators of stress responses, and confirm the identity of R3 as the central nervous system ligand for GPCR135.     

G-protein-coupled receptor (GPCR)-142 does not contribute to relaxin-3 binding in the mouse brain: further support that relaxin-3 is the physiological ligand for GPCR135

Relaxin-3 is a recently discovered member of the insulin/relaxin superfamily that has been shown to be the endogenous ligand for G-protein-coupled receptor (GPCR)135 (SALPR). In addition, relaxin-3 has demonstrated affinity and functional agonism for GPCR142 (GPR100) and LGR7 receptors in vitro. Recent evidence suggests GPCR142 is the insulin-like peptide 5 (INSL5) receptor and LGR7 is the actual relaxin receptor. We have recently described a chimeric R3/I5 peptide that selectively activates GPCR135 and GPCR142, but lacks affinity for LGR7. GPCR142 is a pseudogene in the rat, which allowed the use of [(125)I]-R3/I5 to show GPCR135-like binding sites in the rat central nervous system by autoradiography. However, mouse GPCR142 is a viable gene. In the present study we explore whether GPCR142 is expressed in the mouse brain and whether it is likely to contribute to or interfere with the pharmacological evaluation of relaxin-3 ligands. Competition binding studies confirmed mINSL5 and [(125)I]-mINSL5 bind to mGPCR142 with high affinity. However, no detectable specific [(125)I]-mINSL5 binding sites were detected throughout the mouse brain and unlabelled INSL5 did not displace [(125)I]-R3/I5 binding sites, indicating an absence of detectable GPCR142 binding sites. Consistent with these findings, neither GPCR142 nor INSL5 mRNA were detectable in mouse brain by in situ hybridization. Overall, the distribution of GPCR135 mRNA overlapped with the distribution of GPCR135 binding sites shown by autoradiography using [(125)I]-R3/I5. GPCR135 mRNA and GPCR135 receptor binding sites are most prominent in the mouse amygdala and hypothalamus. These data suggest that relaxin-3/GPCR135 is the receptor ligand pair with physiological relevance in mouse brain.     

The effect of recombinant GM-CSF on the recovery of monkeys transplanted with autologous bone marrow

The regulatory function of recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) on granulocyte production in vivo was evaluated in an autologous bone marrow transplantation model using rhesus monkeys. Monkeys were exposed to 9.0 Gy total body irradiation and then transplanted with 5.0 x 10(7) low-density bone marrow cells/kg. Alzet miniosmotic pumps were subcutaneously implanted to deliver rhGM-CSF at a rate of 50,400 U/kg/d. Minipumps, containing either rhGM-CSF or saline, were implanted between zero and five days after transplantation for seven days. Kinetic recoveries of peripheral blood cells after either saline or rhGM-CSF treatment were compared. Treatment with rhGM-CSF accelerated the recovery of neutrophils. Neutrophils in rhGM-CSF-treated animals recovered to 80% (3.4 x 10(3)/mm3) pre-irradiation control levels by day 20, in comparison with only 33% (0.9 x 10(3)/mm3) recovery for saline control monkeys. In addition, the recovery of neutrophils was enhanced over that of the controls, reaching 140% v 70% on day 30. Another prominent feature of rhGM-CSF-treated monkeys was the accelerated recovery of platelets, reaching near 50% normal levels by day 24 in comparison with 20% of normal levels for controls. The infusion of rhGM-CSF was shown to be an effective regulator of early hematopoietic regeneration, leading to the accelerated recovery of both neutrophils and platelets and then providing a consistent sustained increase of neutrophils even in the absence of rhGM-CSF.     

Deoxygenation inhibits the volume-stimulated, Cl(-)-dependent K+ efflux in SS and young AA cells: a cytosolic Mg2+ modulation

We recently reported that the Cl(-)-dependent K+ (K:Cl) efflux, which can be stimulated by cell swelling in the presence of inhibitors of the Na+ pump (ouabain) and of the Na-K-Cl cotransport (bumetanide), is highly active in young AA and SS RBCs. We report here that deoxygenation inhibits volume-stimulated K:Cl efflux in SS and reticulocyte-enriched density-separated SS and AA RBCs. In SS whole blood, the K:Cl efflux stimulated by hypotonic (220 mOsm) swelling was reduced from 9.2 +/- 2 (mean +/- SE) in oxygen to 2.7 +/- 1.9 (mmol/L cell/h = flux units = FU) (n = 4) under deoxygenated conditions (P less than .005). Deoxygenation also decreased the acid pH-stimulated K:Cl efflux from 5.9 +/- 1.5 to 3.7 +/- 1.1 FU (n = 3) (P less than .025) but did not inhibit NEM-stimulated K:Cl transport. The effect of deoxygenation on density-separated SS cells is similar: When fraction SS2 (reversible discocytes) is deoxygenated under hypotonic conditions, the K:Cl efflux is reduced by 50%. In reticulocyte-enriched AA cells obtained from anemic patients, deoxygenation under hypotonic conditions also reduces K+ efflux by 50%. In SS cells only, deoxygenation under isotonic conditions results in an increased Cl(-)-independent K+ efflux. Because ionized Mg2+ in the cytosol increases during deoxygenation, we investigated the effect of external and internal Mg2+ on the volume-stimulated K:Cl efflux. Removal of external Mg2+ did not influence the rate of transport in oxygenated cells. When internal Mg2+ was clamped at 0.15 mmol/L with A23187 and EDTA at ionized cytosolic Ca2+ = O, however, the inhibitory effect of deoxygenation on the K:Cl efflux was eliminated. We conclude that deoxygenation inhibits the volume-stimulated, Cl(-)-dependent K+ efflux in AA and SS young red cells by concomitantly increasing ionized cytosolic Mg2+.     

International Nosocomial Infection Control Consortium (INICC) report, data summary of 36 countries, for 2004-2009

The results of a surveillance study conducted by the International Nosocomial Infection Control Consortium (INICC) from January 2004 through December 2009 in 422 intensive care units (ICUs) of 36 countries in Latin America, Asia, Africa, and Europe are reported. During the 6-year study period, using Centers for Disease Control and Prevention (CDC) National Healthcare Safety Network (NHSN; formerly the National Nosocomial Infection Surveillance system [NNIS]) definitions for device-associated health care-associated infections, we gathered prospective data from 313,008 patients hospitalized in the consortium's ICUs for an aggregate of 2,194,897 ICU bed-days. Despite the fact that the use of devices in the developing countries' ICUs was remarkably similar to that reported in US ICUs in the CDC's NHSN, rates of device-associated nosocomial infection were significantly higher in the ICUs of the INICC hospitals; the pooled rate of central line-associated bloodstream infection in the INICC ICUs of 6.8 per 1,000 central line-days was more than 3-fold higher than the 2.0 per 1,000 central line-days reported in comparable US ICUs. The overall rate of ventilator-associated pneumonia also was far higher (15.8 vs 3.3 per 1,000 ventilator-days), as was the rate of catheter-associated urinary tract infection (6.3 vs. 3.3 per 1,000 catheter-days). Notably, the frequencies of resistance of Pseudomonas aeruginosa isolates to imipenem (47.2% vs 23.0%), Klebsiella pneumoniae isolates to ceftazidime (76.3% vs 27.1%), Escherichia coli isolates to ceftazidime (66.7% vs 8.1%), Staphylococcus aureus isolates to methicillin (84.4% vs 56.8%), were also higher in the consortium's ICUs, and the crude unadjusted excess mortalities of device-related infections ranged from 7.3% (for catheter-associated urinary tract infection) to 15.2% (for ventilator-associated pneumonia).     

The SH2 domain of P210BCR/ABL is not required for the transformation of hematopoietic factor-dependent cells

Src-homology region 2 (SH2) domains, by binding to tyrosine- phosphorylated sequences, mediate specific protein-protein interactions important in diverse signal transduction pathways. Previous studies have shown that activated forms of the Abl tyrosine kinase, including P210BCR/ABL of human chronic myelogenous leukemia, require the SH2 domain for the transformation of fibroblasts. To determine whether SH2 is also required for Bcr/Abl to transform hematopoietic cells, we have studied two SH2 domain mutations in P210BCR/ABL: a point mutation in the conserved FLVRES motif (P210/R1033K), which interferes with phosphotyrosine-binding by SH2, and a complete deletion of SH2 (P210/delta SH2). Despite a negative effect on intrinsic Abl kinase activity, both P210 SH2 mutants were still able to transform the hematopoietic factor-dependent cell lines Ba/F3 and FDC-P1 to growth factor independence. Unexpectedly, both mutants showed greater transforming activity than wild-type P210 in a quantitative transformation assay, probably as a consequence of increased stability of the SH2 mutant proteins in vivo. Cells transformed by both P210 SH2 mutants were leukemogenic in synaptic mice and P210/r1053K mice exhibited a distinct disease phenotype, reminiscent of that induced by v-Abl. These results demonstrate that while the Abl SH2 domain is essential for BCR/ABL transformation of fibroblasts, it is dispensable for the transformation of hematopoietic factor-dependent cell lines.     

Amifostine improves the antileukemic therapeutic index of mafosfamide: implications for bone marrow purging

One of the principal challenges of cancer chemotherapy is the relative inability of most anticancer drugs to distinguish between normal and neoplastic tissues. Consequently, a broad range of toxicities are experienced by patients, especially myelosuppression. Amifostine, a phosphorylated aminothiol, increases the selectivity of specific anticancer drugs for neoplastic cells by protecting normal tissues. One potential application of this protector is during bone marrow purging to selectively remove contaminating cancer cells. This study took normal or leukemic marrow from human subjects and evaluated the ability of amifostine to selectively protect normal bone marrow progenitor cells versus leukemic progenitor cells from the cytotoxic effect of mafosfamide. The dose response of mafosfamide amifostine on leukemia colony-forming units or normal marrow progenitor cells was determined and the LD95 was calculated. Amifostine pretreatment resulted in a statistically significant protection of granulocyte-macrophage colony- forming units and erythroid blast-forming units from the toxicity of mafosfamide (P = .031). Thus, amifostine protection of normal marrow progenitor cells allows a higher LD95 concentration of mafosfamide to be used in ex vivo purging. In contrast, amifostine pretreatment increased the cytotoxicity of mafosfamide on the fresh human leukemia progenitor cells (P = .006). The dual effect of amifostine protection of normal marrow progenitor cells coupled with amifostine-induced sensitization of the leukemia cells increases the possible cell-kill of leukemic stem cells. With amifostine pretreatment, at the LD95 concentrations of mafosfamide for marrow progenitor cells, there was an estimated 6 log increase in cell-kill of the leukemia cells. This selective cell-kill offers the potential for lowering the incidence of leukemic relapse, while preserving more normal stem cells for autologous transplantation.     

Methotrexate, cyclosporine, or both to prevent graft-versus-host disease after HLA-identical sibling bone marrow transplants for early leukemia?

Optimal prophylaxis of graft-versus-host disease (GVHD) is controversial. We compared efficacy of three posttransplant immune suppressive regimens in 2,286 recipients of HLA-identical sibling bone marrow transplants for acute lymphoblastic leukemia (ALL) in first remission, acute myelogenous leukemia (AML) in first remission, or chronic myelogenous leukemia (CML) in first chronic phase. Six hundred forty received methotrexate, 977 received cyclosporine, and 669 received combined cyclosporine and methotrexate. In children, the three regimens resulted in similar outcomes. In adults, cyclosporine and methotrexate had comparable risks of acute and chronic GVHD. Compared with methotrexate, cyclosporine was associated with less interstitial pneumonia (relative risk [RR] = 0.6; P < .001), less treatment-related mortality (RR = 0.6; P < .001), more relapses (RR = 1.6; P < .05), and less treatment failure (relapse or death from any cause; RR = 0.7; P < .001). Different effects were observed in different leukemias. In ALL, the rate of leukemia relapse was increased with cyclosporine versus methotrexate, with no effect on other outcomes. In AML and CML, interstitial pneumonia, treatment-related mortality, and treatment failures were decreased with cyclosporine, with no increase in relapse. Similar analyses comparing cyclosporine plus methotrexate with cyclosporine alone showed that adults receiving the combination had less acute GVHD (RR = 0.5; P < .001), less chronic GVHD (RR = 0.7; P < .01), and less interstitial pneumonia (RR = 0.7; P < .001). Treatment failure (RR = 0.8; P < .05) was marginally reduced. Separate analyses in ALL and AML showed less acute GVHD with combined therapy, but no significant effect on other outcomes. In CML, acute GVHD, interstitial pneumonia, treatment-related mortality, and treatment failure were decreased with combined therapy.