Gene therapy for severe combined immunodeficiencies

Severe combined immune deficiencies (SCIDs) are a group of monogenic diseases resulting in profound disturbances of lymphocyte development and function. Affected individuals are prone to life-threatening infections and without treatment do not survive beyond the first year of life. Haematopoietic stem cell transplantation from a well-matched donor offers high rates of survival, but in the absence of a suitable matched donor, parental haploidentical transplants are associated with greater complications, lower success rates and in some instances poor long-term immune recovery. Alternative therapeutic options based on correction of the defective gene by retroviral gene delivery have been used to correct X-linked SCID (SCID-X1) and adenosine deaminase-deficient SCID (ADA-SCID). A number of clinical trials have established that ex vivo gene transfer into haematopoietic progenitor cells allows effective recovery of immune defects and that gene therapy can offer a successful alternative to transplantation. The development of leukaemia as a result of insertional mutagenesis in one trial of gene therapy for SCID-X1 has raised concerns regarding the toxicity of retroviral vector-based gene delivery. These side effects are now being studied in detail and measures to prevent such events through alternative vectors delivery systems are in development at present.     

慢性低氧对大鼠血浆腺苷水平的影响

目的研究慢性低氧时大鼠血浆腺苷水平的变化及其机制。方法将42只雄性SD大鼠随机分成常氧组(对照组),低氧1 d、3 d、5 d、7 d、14 d、21 d组(H1、H3、H5、H7、H14、H21组),每组6只。分别于低氧第1天、第3天、第5天、第7天、第14天及第21天测定各组大鼠血浆腺苷水平、腺苷脱氨酶(ADA)活性以及血浆中5’-核苷酸酶(5’-NT)水平。应用SPSS 16.0软件进行统计学分析。结果低氧1 d后大鼠血浆腺苷水平开始升高,于第3天达到最高峰,与对照组比较差异有统计学意义(P<0.001);此后,随着低氧时间的延长,血浆腺苷水平逐渐下降,第14天及第21天与对照组比较差异均无统计学意义(Pa>0.05)。血浆5’-NT水平在低氧第3天增高最显著(P<0.001),在低氧3 d后逐渐下降,但仍高于对照组(P<0.001)。血浆ADA活性在慢性低氧第1天、第3天较对照组明显增高(Pa<0.001),随着低氧时间的延长,其活性稍下降,但仍明显高于对照组(P<0.001)。结论慢性低氧在早期可引起血浆腺苷水平增加,后期血浆腺苷水平逐渐降低,其变化与5’-NT水平和ADA活性有关。     

Role of endothelium in adenosine receptor-mediated vasorelaxation in hypertensive rats

The present study was designed to investigate the role of endothelium derived relaxing factor nitric oxide (NO) in adenosine A2 receptor mediated vasorelaxation in normotensive (WKY) and hypertensive (SHR) rat aortic ring preparations. Adenosine analogues, 2-chloroadenosine (CAD) and 5-ethylcarboxamidoadenosine (NECA) produced concentration-dependent (10(-9)-10(-4) M) relaxation in phenylephrine (1 x 10(-6) M) precontracted vascular rings, which was significantly shifted to the right in SHR compared to WKY rats. Endothelium removal attenuated CAD and NECA relaxation responses in both SHR and WKY and abolished the difference in relaxation between SHR and WKY vascular tissues. The relaxation response to CAD was antagonised by adenosine A2 receptor antagonist, 8-sulfophenyltheophylline (8-SPT, 50 x 10(-6) M). The antagonism by 8-SPT was lower in SHR as compared to WKY tissues. L-monomethylarginine (L-LMMA) (30 x 10(-6) M) significantly shifted the CAD relaxation to the right, which was reversed by the addition of L-arginine (100 x 10(-6) M) in both SHR and WKY rats. However, the rightward shift by L-NMMA was smaller in SHR compared to WKY vascular tissues. Vasorelaxation response to acetylcholine (1 x 10(-6) M) was significantly inhibited (50%) in SHR rings compared to WKY. The relaxation produced by sodium nitroprusside (10(-9)-10(-5) M) in endothelium-intact and -denuded aortic rings showed no difference between SHR and WKY. Isoproterenol produced concentration-dependent (10-9-10-5 M) relaxation, which was shifted to the right in SHR compared to WKY rings with an intact endothelium, while the removal of endothelium abolished the difference in the response between SHR and WKY. The results suggest: (i) adenosine A2 receptors mediate vasorelaxation in part through endothelium possibly by releasing nitric oxide (NO); (ii) the impairment of endothelium may be one of the factors for the attenuation of adenosine receptor and receptor-mediated responses in SHR.     

Endothelin does not affect aggregation of human platelets

Summary. Endothelin (ET-1) is a recently discovered endothelial-derived peptide with pronounced vasoconstrictor activity. The present study addressed whether ET-1, in analogy with several other vasoactive agents, can induce or modulate aggregation of human platelets in vitro. Venous blood from healthy donors was collected in citrate or heparin and platelet-rich plasma (PRP) was prepared. Portions of the PRP were added to drugs, and platelet aggregation was recorded according to Born & Cross (1963). ET-1 added to the PRP (final concentrations 1–100 nM) did not induce aggregation of platelets, either in citrate- or heparin-containing plasma. Adenosine-diphosphate (0·5-2 μM) or thrombin (0·1-0·4 NIH units ml^-1) induced dose-dependent aggregation of platelets in citrate- or heparin-containing PRP; such aggregation was, however, not affected by ET-1 (1–100 μM) either. We conclude that ET-1, in contrast to other endothelial-derived vasoactive agents, lacks direct effect on platelet aggregation in vitro.     

葛根素合用心先安治疗难治性心力衰竭的临床观察

目的 :探讨葛根素合用心先安治疗难治性心力衰竭的临床疗效。方法 :6 2例难治性心力衰竭患者随机分为对照组和治疗组。对照组常规治疗〔吸氧、利尿剂、洋地黄、血管扩张剂、血管紧张素转换酶抑制剂(ACEI)、控制感染和对症支持疗法〕。治疗组在常规治疗基础上 ,葛根素 0 .4 g加入质量分数为 5 %的葡萄糖2 5 0 ml,心先安 12 0 m g加入 5 %葡萄糖 2 5 0 ml静脉点滴 ,2周为 1个疗程 ,比较两组心功能的改善情况。结果 :两组治疗后心功能及心脏指数有显著改善 (P均 <0 .0 1) ,治疗组与对照组比较有明显差异 (P<0 .0 5 )。结论 :葛根素合用心先安治疗难治性心力衰竭疗效明显 ,安全可靠。     

Adenosine A1 Antagonism Attenuates β-adrenergic–resistant Sudden Hypoxic Cardiac Insufficiency

Objectives: In states such as hypoxia, shock, and cardiac arrest, compromised systemic oxygenation or perfusion appears to induce cardiac insufficiency that can be resistant to β‐adrenergic drugs. Elevated levels of adenosine may mediate such β‐adrenergic–resistant cardiac insufficiency via the adenosine A₁ receptor (A₁AdoR). The objective of this study was to test the hypothesis that selective A₁AdoR antagonism attenuates hypoxic cardiac insufficiency more efficaciously than β₁‐adrenergic agonism or nonselective adenosine antagonism. Methods: Rats were paralyzed and ventilated to a pCO₂ level of 35–40 mm Hg. Ten minutes before hypoxia (inspired O₂ concentration = 5%), rats were treated intravenously with one of the following: 0.1 mg/kg BG‐9719 (n= 9), 10 mg/kg NPC‐205 (n= 10; BG‐9719 and NPC‐205 are selective A₁AdoR antagonists, with durations of action of 30–60 minutes and 60–90 minutes, respectively), 10 mg/kg aminophylline (n= 12), 5 μg/kg/min dobutamine (n= 11), or control solutions. These drug doses maximized survival duration in dose‐response studies. Results: Before hypoxia, cardiac work was increased more by aminophylline and dobutamine than by BG‐9719. Mean (±SEM) duration of survival (in minutes) after hypoxia increased from <13 (control solutions) to 13.8 (±1.4) (dobutamine), 20.0 (±1.6) (aminophylline), 31.7 (±4.6) (BG‐9719), and 40.5 (±7.5) (NPC‐205) (p < 0.0001). Heart rate and dP/dt decreased rapidly after hypoxia, but decreases were attenuated with BG‐9719 and NPC‐205 compared with dobutamine (p < 0.05) and tended toward attenuation with aminophylline. Conclusions: BG‐9719 and NPC‐205 improved survival duration, heart rate, and left ventricular contractility during hypoxia more efficaciously than dobutamine and possibly aminophylline. Selective A₁AdoR antagonists warrant further study as alternatives to β‐adrenergic agonists in hypoxia, shock, and cardiac arrest, in which compromised systemic perfusion or oxygenation impairs cardiac output.     

Protein kinase and adenylate cyclase of erythrocyte membrane from patients with duchenne muscular dystrophy

In freshly prepared erythrocyte membranes from normal individuals and from patients with Duchenne progressive muscular dystrophy the endogenous protein kinase and the cAMP stimulated phosphorylation was identical for the three main ³²P proteins including spectrin (protein band II). Another enzyme, adenylate cyclase, was found unchanged. Altered protein kinase and adenylate cyclase has been reported in this disorder. We have no explanation for these discrepancies.