In vitro characterization of the human recombinant soluble granulocyte- macrophage colony-stimulating factor receptor

We have cloned, expressed, and partially purified a naturally occurring, truncated, soluble form of the human granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor alpha subunit to investigate its biochemical and biologic properties. The soluble receptor species lacks the transmembrane and cytoplasmic domains that are presumably removed from the intact receptor cDNA by a mechanism of alternative splicing. The resulting soluble 55- to 60-kD glycosylated receptor species binds GM-CSF with a dissociation constant (kd) of 3.8 nmol/L. The soluble GM-CSF receptor successfully competes for GM-CSF binding not only with the transmembrane-anchored GM-CSF receptor alpha subunit but also with the native oligomeric high-affinity receptor complex. In addition, in human bone marrow colony-forming assays, the soluble GM-CSF receptor species can antagonize the activity of GM-CSF. Our data suggest that the soluble GM-CSF receptor may be capable of acting in vivo as a modulator of the biologic activity of GM-CSF.     

Angiogenic therapy for the chronically ischemic lower limb in a rabbit model

The purpose of this study was to evaluate the long-term effectiveness of basic fibroblast growth factor (bFGF) in achieving neovascularization following ischemia from arterial ligation and to determine an optimal dosage level. We used an Ameroid constrictor to produce progressive occlusion of the left femoral artery of rabbits. At 2 weeks, the rabbits were randomized to receive intravenous injection of vehicle (group A, n = 15); 3 microg/kg/day bFGF (group B, n = 12); 10 microg/kg/day bFGF (group C, n = 12); or 16 microg/kg/day bFGF (group D, n = 15) for 3 days. At 1 to 37 days after surgery, we assessed limb neovascularization by transcutaneous oximetry (TCPO(2)), angiography, heart rate, arterial pressure, peripheral vascular resistance (PRU), and muscle blood flow (MBF) during steady-state intra-arterial infusion of saline (basal), acetylcholine, papaverine, or serotonin under anesthesia and capillary density (cap/mm(2)) and capillary per muscle fiber ratio (cap/F). Groups B and C showed significantly greater change in TCPO(2) over time than groups A and D (P < 0.0001). Group D showed the lowest TCPO(2) values from days 14 to 37 and group C the highest. Groups B and C showed a higher number of vessels filled with contrast agent than groups A and D (P < 0.0001). Calf cap/mm(2) and cap/F were significantly higher in groups B and C than groups A and D (P < 0.0001). Calf basal MBF values were higher in groups B and C than in groups A and D, but were not statistically significant. Group D showed the highest level in basal PRU. There were no significant differences in heart rate or blood pressure among the groups. These results show (1) treatment with bFGF has no adverse hemodynamic effects, (2) bFGF enhances angiogenesis and circulation at moderate doses, and these effects persist at least several weeks, and (3) high doses of bFGF may inhibit angiogenesis and collateral circulation.     

A prospective study on defecation frequency, stool weight, and consistency

It has been commonly believed that children in developing countries pass stools that are very different from those of developed countries. A community based study on defecation frequency, stool weight, and consistency was conducted in a cohort of 300 Myanmar (Burmese) children aged 1 to 4 years. Most (80.3%) children opened their bowels daily and none passed more than three stools a day. The mean (SD) defecation frequency was 6.98 (1.94) times a week and total stool weight was 596 (221) g a week. The majority (61%) of children passed soft stools. At all ages, there was no significant difference in the defecation frequency, stool weight, and consistency between boys and girls, those on adult style diet and those partially weaned, and between age groups.     

Percutaneous Approach to Achieve Therapeutic Myocardial Angiogenesis

Myocardial therapeutic angiogenesis is a novel approach for treating the large number of patients with advanced symptomatic coronary artery disease not amenable to conventional revascularization approaches. Proof of concept has been demonstrated in animal models of myocardial ischemia, and preliminary results suggest possible benefit in clinical trials of direct surgical (transepicardial) delivery of proteins and recombinant genes encoding angiogenic growth factors. Catheter-based intramyocardial gene delivery strategies have been tested in parallel, with the assumption that the less invasive nature and the potential for multiple treatment sessions would make this technique more applicable. Currently, most of the data relating to the catheter-based transendocardial delivery of angiogensis factors are derived from the experience with a single device (Biosense; Johnson & Johnson, Skillman, NJ). Using this injection platform, catheter-based gene delivery was demonstrated in animals to be safe and feasible, with a transfection yield similar to that achieved by the direct transepicardial approach. At the time of this review, more than 45 patients have been enrolled in Phase I clinical trials that evaluate the safety and feasibility of transendocardial delivery of adenovirus and plasmid-mediated gene transfection as well as cellular elements.     

Lack of correlation between angiographic grading of collateral and myocardial perfusion and function: implications for the assessment of angiogenic response

BACKGROUND: Angiographic assessment of apparent collaterals (AAC) has been used to quantify the angiogenic response to interventions designed to enhance myocardial perfusion and function in ischemic myocardium. However, the accuracy with which AAC reflects actual myocardial blood flow (MBF) and regional contractility has not been established. OBJECTIVE: To examine the relationships between myocardial tissue perfusion, AAC grade and myocardial function in a porcine model of chronic myocardial ischemia. METHODS: AAC (with results visually graded as 0-3) was performed 4 weeks after placement of an ameroid constrictor around the left circumflex artery in pigs (n= 27). Fluorescent microspheres were used to quantify regional endocardial, epicardial, and transmural MBF, and echocardiography was used to assess percentage thickening of myocardium (PTM) at rest and under stress (pacing). RESULTS: There was no significant correlation between AAC grading and endocardial, epicardial or transmural MBF. MBF but not AAC grade was correlated to PTM at rest according to the formula PTM=0.06+0.42MBFtransmural (r= 0.39, P= 0.047). CONCLUSION: Results of simple AAC are not correlated with myocardial perfusion and function and probably should not be used as a primary endpoint in clinical studies designed to enhance myocardial perfusion in ischemic regions.     

氯喹对烟雾吸入伤大鼠肺细胞膜ATP酶活性和丙二醛含量的影响

目的：探讨氯喹对烟雾吸入伤大鼠肺细胞膜ＡＴＰ酶活性及丙二醛含量的影响,方法：８０只Ｗｉｓｔａｒ大鼠随机分成正常对照组,烟雾吸入伤１,３,６,１２和２４ｈ组以及氯喹治疗６ｈ和１２ｈ组,分别于各时相点活杀动物,取肺制备膜制剂,用生化比色法测定膜上Ｎａ＾＋,Ｋ＾＋－ＡＴＰ酶Ｍｇ＾２＋－ＡＴＰ酶和Ｃａ＾２＋－ＡＴＰ酶活性,用比色法测定膜上丙醛含量,并用定磷法测定膜总磷脂含量,结果：烟雾吸入伤后,肺细胞膜３     

Could plasmid‐mediated gene transfer into the myocardium be augmented by left ventricular guided laser myocardial injury?

Early studies have indicated no correlation between the amount of mechanical injury and the level of myocardial gene expression following direct plasmid vector injection. Recently, however, evidence suggests that combined laser myocardial injury and plasmid-based gene delivery exert synergistic effects on gene expression and activity. The purpose of the study was to determine whether laser-induced myocardial injury followed by transendocardial gene transfer increases gene expression compared to gene transfer alone. We assessed the ability of a plasmid vector to express its transgene after injection into porcine ischemic myocardium with and without preceding laser myocardial injury. Thirteen animals had transendocardial injections of the luciferase reporter gene in a plamid vector using a catheter-based injection system. Injections (0.5 mg per animal, 50 microg per injection site) were divided into 10 sites in the ischemic territory. Eight animals underwent transendocardial laser injury of the ischemic region (2 Joule per pulse x 10 sites) prior to gene delivery. In five animals, gene injection sites were dispersed between laser channels, and in three animals laser and gene delivery were applied in close proximity (< 5 mm) or at the same location. Luciferase activity was measured at 3 and 7 days. Luciferase expression in ischemic zones was markedly elevated at day 3 and 7, and similar whether animals were pretreated using laser injury followed by gene transfer compared to gene transfer alone. Neither same-spot injection nor dispersed gene delivery were associated with augmented gene expression compared to gene transfer alone. Using the above-described catheter-based approach to combine localized laser injury and injection of naked DNA into ischemic myocardium, laser injury did not augment gene expression above levels present with gene transfer alone.     

中频交变磁场照射后小鼠的行为学变化

目的:目前电磁辐射对生物体行为学方面的研究还很薄弱,设立不同磁场的强度和不同照射的周期,观察中频领域磁场照射对小鼠的自主活动和学习记忆的影响。方法:实验于2007-05-10/06-15在清华大学医学院和中国医学科学院药用植物研究所完成。①实验材料:磁场发生装置:中频交变磁场发生装置由清华大学工程物理系医学物理与工程研究所自主研发,可产生频率为40kHz,场强为28.8A/m,28.8kA/m的中频交变磁场。自主活动测试箱:中国医学科学院药用植物研究所提供,为一可封闭的金属箱,内置摄像头。4只黑色塑料测试桶分别置于箱子四角。水迷宫测试箱:中国医学科学院药用植物研究所提供。②实验动物及方法:将80只小鼠随机分为不同场强照射组和对照组。强磁场照射1组:11.6kA/m/40kHz,1h/d,连续照射7d。强磁场照射2组:11.6kA/m/40kHz,2h/d,连续照射7d。强磁场照射3组:11.6kA/m/40kHz,2h/d连续照射15d。弱磁场照射组:28.8kA/m/40kHz,2h/d,连续照射7d。对照组除了未放入磁场照射,其他条件与照射组一致。实验过程中对动物处置符合动物伦理学要求。③实验评估:观察其一般活动的改变,并采用自主活动测试箱和水迷宫测试箱进行测试,观察各组小鼠的自主活动和学习记忆的改变。结果:①一般行为观察:与对照组小鼠对比,经过中频交变磁场照射过的各组小鼠活跃度减低,毛色较差。强磁场照射3组(145G,2h/d,连续15d)于第11天和13天分别死亡1只。②自主活动检测结果:强磁场照射2,3组小鼠的运动路程、运动速度、运动时间明显低于对照组(P<0.05)。③水迷宫测试结果:在学习记忆检测阶段撤掉平台,发现各组动物2min内穿越平台原来所在象限的次数没有明显差别(P>0.05)。结论:中频交变磁场照射会给小鼠的自发活动造成一定影响,对学习记忆没有影响。