CGX-1051, a peptide from Conus snail venom, attenuates infarction in rabbit hearts when administered at reperfusion

CGX-1051, isolated from the venom of the marine snail Conus purpurasens, was previously noted to interact with potassium channels. Since potassium channels play an important role in cardiac physiology, we assessed the effect of CGX-1051 on infarct size in a rabbit heart model of ischemia/reperfusion. A coronary branch was occluded for 30 minutes followed by 3 hours of reperfusion in in situ and 2 hours in in vitro preparations. Infarct size was measured with triphenyltetrazolium chloride staining and expressed as a percent of the risk zone. In in situ studies, a bolus intravenous injection of CGX-1051, either 10 or 100 microg/kg, administered 5 minutes before reperfusion, reduced infarct size from 40.4 +/- 2.8% of the risk zone in untreated animals to 19.8 +/- 3.8% and 15.0 +/- 1.9%, respectively. One microg/kg CGX-1051 was not protective. To see if the salvage was sustained, two groups of rabbits underwent 72 hours of reperfusion. The dose of 10 microg/kg infused 5 minutes before reperfusion reduced infarct size from 37.0 +/- 1.6% in untreated rabbits to 15.5 +/- 2.0%. When administered 10 minutes after reperfusion had begun, 100 microg/kg CGX-1051 had no effect. CGX-1051 also reduced infarct size in crystalloid-perfused, isolated rabbit hearts suggesting that protection did not depend on circulating leukocytes. The mitochondrial KATP inhibitors glibenclamide and 5-hydroxydecanoate and the MEK(1/2), ERK and hence, inhibitor PD 98059 aborted protection from CGX-1051. These data indicate that functionally active ERK and mitochondrial KATP channels are necessary for protection. CGX-1051 caused no hemodynamic alterations at any dose tested. We conclude that CGX-1051 has a powerful anti-infarct effect when given just before reperfusion.     

一氧化氮合酶mRNA和蛋白在骨巨细胞瘤中的表达及意义

背景与目的：近年的研究发现,一氧化氮在恶性肿瘤的发生和发展中起着重要作用,且在正常骨细胞中检测到一氧化氮合酶(nitric oxide synthase,NOS)的活性,但目前未见有关骨巨细胞瘤(giant cell tumors of bone,GCT)NOS的活性及其与GCT病理分级和肿瘤复发关系的报道。本研究探讨GCT组织中NOS mRNA和蛋白的表达,及其与GCT病理分级、肿瘤复发的关系。方法：用NOS的cDNA探针检测14例冻存GCT组织中原生型一氧化氮合酶(constitutive NOS,cNOS)、诱导型一氧化氮合酶(inducible NOS,iNOS)mRNA的表达,用抗NOS1、NOS2、NOS3的多克隆抗体检测42例GCT石蜡包埋组织中NOSl、NOS2、NOS3蛋白的表达。结果：(1)在14例冻存的GCT组织中多核巨细胞(multinuclear giant cell,MGC)cNOS和iNOS mRNA的阳性率分别为78．6％和57．1％,单核细胞(mononuclear cell,MC)的阳性率均为35．7％;(2)病理分级Ⅱ、Ⅲ级MGC的cNOS mRNA阳性率明显高于I级MGC(P=0．008);(3)在42例GCT的石蜡包埋组织中,MGC中NOS1、NOS2、NOS3蛋白的阳性率分别为85．7％、59．5％和31．0％,MC的阳性率分别为54．8％、28．6％和14．3％;(4)病理分级Ⅱ、Ⅲ级GCT组织中MC的NOS1阳性率明显高于I级组(P=0．006);(5)复发组GCT组织MC的NOS1阳性率明显高于无复发组(P=0．018),复发组GCT组织中MGC的NOS3蛋白阳性率明显高于无复发组(P=0．041)。结论：GCT组织中NOS的表达,尤其是cNOS在MC中的表达,与病理分级和肿瘤复发有密切关系。     

AMP579 is revealed to be a potent A2b-adenosine receptor agonist in human 293 cells and rabbit hearts

The mixed A₁/A_2a-adenosine agonist AMP579 given at reperfusion is protective in animal models of myocardial infarction. Receptor-blocking studies have indicated that the protection came from an adenosine receptor (AR), but neither A₁- nor A_2a-selective agonists could duplicate its protection. We recently found that A_2b-selective agonists given at reperfusion are protective, and, therefore, tested whether AMP579 might also be an A_2b agonist. We used human embryonic kidney cells overexpressing human A_2b receptors as an assay system. In these cells, A_2b receptor occupancy causes phosphorylation of ERK. AMP579 induced ERK phosphorylation with an EC₅₀ of 250 nM and this phosphorylation could be blocked by MRS1754 or PSB1115, two highly selective blockers of human A_2b receptors. We attempted to confirm our A_2b hypothesis in a rabbit heart model of ischemia–reperfusion. AMP579 (500 nM) for 1 h starting at reperfusion reduced infarct size in isolated rabbit hearts exposed to 30 min of regional ischemia and 2 h of reperfusion (12.9 ± 2.2% infarction of risk zone vs. 32.0 ± 1.9% in untreated hearts). PSB1115 (500 nM) given for the first 15 min of reperfusion blocked AMP579’s protection (32.2 ± 3.1% infarction) which is consistent with an A_2b mechanism. We conclude that AMP579 is a non-selective, but potent A_2b-AR agonist, and that its protection against infarction is through that receptor.     

2003～2008年住院儿童死因及变化趋势

目的:通过对某院住院儿童死亡病例进行分析,研究该地区儿童死亡的主要死因及变化趋势,改善干预措施,降低该地区的儿童死亡率。方法:对某院165例死亡儿童病例进行回顾性分析,采用SPSS 13.0软件进行统计处理。结果:该院6年来住院儿童病死率比较无统计学差异(P>0.05)。该地区儿童的主要死因依次为新生儿疾病、呼吸系统疾病、损伤与中毒、先天畸形。新生儿疾病是主要死因,先天畸形的死亡构成有上升的趋势,感染性疾病的死亡构成呈下降趋势,其中传染病总体呈下降趋势。各年龄组的病死率有明显统计学差异(P<0.05)。男女性别各年龄组死亡构成无统计学差异(P>0.05),但城乡之间有统计学差异(P<0.05)。结论:加强高危孕妇的保健及监测工作,尤其是围生期及新生儿期的保健工作,搞好产前诊断和缺陷胎儿筛查,把握抢救时机,提高抢救水平,可明显降低儿童死亡人数。     

A2B adenosine receptors inhibit superoxide production from mitochondrial complex I in rabbit cardiomyocytes via a mechanism sensitive to Pertussis toxin

BACKGROUND AND PURPOSE

A_2B adenosine receptors protect against ischaemia/reperfusion injury by activating survival kinases including extracellular signal-regulated kinase (ERK) and phosphatidylinositol 3-kinase (PI3K). However, the underlying mechanism(s) and signalling pathway(s) remain undefined.

EXPERIMENTAL APPROACH

HEK 293 cells stably transfected with human A_2B adenosine receptors (HEK-A_2B) and isolated adult rabbit cardiomyocytes were used to assay phosphorylation of ERK by Western blot and cation flux through cAMP-gated channels by patch clamp methods. Generation of reactive oxygen species (ROS) by mitochondria was measured with a fluorescent dye.

KEY RESULTS

In HEK-A_2B cells, the selective A_2B receptor agonist Bay 60-6583 (Bay 60) increased ERK phosphorylation and cAMP levels, detected by current through cAMP-gated ion channels. However, increased cAMP or its downstream target protein kinase A was not involved in ERK phosphorylation. Pertussis toxin (PTX) blocked ERK phosphorylation, suggesting receptor coupling to G_i or G_o proteins. Phosphorylation was also blocked by inhibition of PI3K (with wortmannin) or of ERK kinase (MEK1/2, with PD 98059) but not by inhibition of NO synthase (NOS). In cardiomyocytes, Bay 60 did not affect cAMP levels but did block the increased superoxide generation induced by rotenone, a mitochondrial complex I inhibitor. This effect of Bay 60 was inhibited by PD 98059, wortmannin or PTX. Inhibition of NOS blocked superoxide production because NOS is downstream of ERK.

CONCLUSION AND IMPLICATIONS

Activation of A_2B adenosine receptors reduced superoxide generation from mitochondrial complex I through G_i/o, ERK, PI3K, and NOS, all of which have been implicated in ischaemic preconditioning.     

结直肠腺癌EMMPRIN蛋白的表达及其临床病理学意义

目的:研究结直肠腺癌细胞外基质金属蛋白酶诱导因子(extracellularmatrixmetalloproteinaseinducer,EMMPRIN)蛋白表达的临床病理意义。方法:免疫组织化学(SP)法检测89例结直肠腺癌组织中EMMPRIN的表达,分析EMMPRIN与组织学类型、分化程度、肿瘤神经组织浸润、浸润肠壁深度、淋巴结转移和Dukes分期等生物学行为的关系。结果:全组结直肠腺癌EMMPRIN的阳性率为43%(38/89)。53例癌旁腺上皮的阳性率为17%(9/53),明显低于同组腺癌组织的58%(31/53)(P=0.016)。EMMPRIN表达与组织学类型、分化程度、肿瘤神经组织浸润、浸润肠壁深度、淋巴结转移和Dukes分期均无关(P>0.05)。结论:EMMPRIN在结直肠腺癌中的表达明显较癌旁腺上皮增多,但与癌的生物学行为关系不大。