大鼠眼外肌成肌细胞的增殖及分化特征

目的:完善眼外肌成肌细胞体外培养、鉴定的方法及观察其生物学特性。方法:实验于2005-02/08在青岛大学医学院附院中心实验室(省级实验室)完成。取出生后3～7d的大鼠,通过大鼠眼外肌细胞的取材、分离、消化、培养等技术,观察细胞的形态、生长曲线、细胞融合率,观察大鼠眼外肌卫星细胞的增殖与分化能力,利用成肌细胞标记物α-横纹肌肌动蛋白、中间丝结蛋白免疫细胞化学染色对所获得的细胞进行鉴定。结果:①成肌细胞的生长情况:在生长培养基作用下,细胞增殖旺盛;在分化培养基条件下,细胞分化良好,可融合成肌管。②成肌细胞融合率:在24h和48h融合率提高明显,72h达高峰,之后不再变化。③细胞免疫化学检测结果:α-横纹肌肌动蛋白和中间丝结蛋白免疫细胞化学染色阳性。结论:体外培养的大鼠眼外肌卫星细胞具有良好的增殖与分化能力,其生物学特征同骨骼肌卫星细胞。     

Augmentation of spontaneous macrophage-mediated cytolysis by eosinophil peroxidase

Eosinophil peroxidase (EPO), a cationic protein purified from horse blood, adhered to four different types of tumor cells, markedly potentiating their lysis by preformed or enzymatically generated H(2)0(2) (up to 76-fold, as assayed in serum-containing tissue culture medium without supplemental halide). Similarly, compared with uncoated tumor cells, EPO-coated tumor cells were up to 32 times more sensitive to lysis when incubated with macrophages or granulocytes whose respiratory burst was triggered by PMA. However, EPO-coated tumor cells were also readily lysed by bacillus Calmette- Guerin-activated macrophages in the absence of exogenous triggering agents. This spontaneous cytolysis was rapid (50 percent at 2 h) and potent (50 percent lysis at macrophage/tumor cell ratios of 1.5 to 4.6), and was observed with both a peroxide-sensitive tumor (TLX9) and a peroxide-resistant tumor (NK lymphoma). Under the conditions used, neither EPO alone nor macrophages alone were spontaneously cytolytic. Neither EPO nor EPO-coated tumor cells triggered a detectable increment in H(2)0(2) release from macrophages. Nonetheless, spontaneous macrophage-mediated cytolysis of EPO- coated tumor cells was completely inhibitable by catalase (50 percent inhibition, 23 U/ml), although not by heated catalase, indicating a requirement for H(2)0(2). Cytolysis was also completely inhibitable by azide (50 percent inhibition, 2.6 X 10 -5 M), indicating a requirement for enzymatic activity of EPO. Thus, a cytophilic peroxidase from eosinophils and H(2)0(2) spontaneously released from activated macrophages interacted synergistically in a physiologic medium to destroy tumor cells.     

Providing monovalent oral polio vaccine type 1 to newborns: findings from a pilot birth-dose project in Moradabad district, India

Problem

Poliovirus transmission remained a public health challenge in western Uttar Pradesh, India in late 2005 and early 2006. In 2006, the India Expert Advisory Group for Polio Eradication concluded that, given the peak incidence of polio among children 6 to 12 months of age, a targeted birth dose of oral polio vaccine may be necessary to interrupt intense poliovirus transmission in high risk areas.

Approach

The Government of Uttar Pradesh, the National Polio Surveillance Project and the United Nations Children’s Fund (UNICEF) implemented a pilot birth-dose project aimed at identifying and vaccinating all newborns with a dose of oral polio vaccine within 72 hours of birth in an effort to evaluate operational feasibility and potential impact on population immunity.

Local setting

The project was piloted in Moradabad district: zone 7 in Moradabad City (urban setting), Kunderki block (rural setting) and in select birthing hospitals.

Relevant changes

Between July 2006 and February 2007, 9740 newborns were identified, of which 6369 (65%) were vaccinated by project personnel within 72 hours of birth. Project coverage (for total newborns vaccinated) ranged from 39% (in zone 7) to 76% (in Kunderki block) of the estimated number of newborns vaccinated during previous supplemental immunization activities.

Lessons learned

Birth-dose coverage among newborns was lower than expected. Expansion costs were estimated to be high, with marginal impact. The project, however, provided opportunities to strengthen newborn tracking systems which have increased the number of newborns and young infants vaccinated during supplemental immunization activities and enrolled in routine programmes.     

Dissociation between microneurographic and heart rate variability estimates of sympathetic tone in normal subjects and patients with heart failure.

The concept that spectral analysis of heart rate variability (HRV) can estimate cardiac sympathetic nerve traffic in subjects with both normal and impaired left ventricular systolic function has not been validated against muscle sympathetic nerve activity (MSNA). We used coarse-graining spectral analysis to quantify the harmonic and non-harmonic, or fractal, components of HRV and to determine low-frequency (0.0-0.15 Hz; PL) and high-frequency (0.15-0.5Hz; PH) harmonic power. To test the hypothesis that MSNA and HRV representations of sympathetic nerve activity (PL and PL/PH) increase in parallel in heart failure, we recorded heart rate and MSNA during supine rest in 35 patients (age 52.4+/-2 years; mean+/-S. E.M.), with a mean left ventricular ejection fraction of 22+/-2%, and in 34 age-matched normal subjects. Power density was log10 transformed. Mean MSNA was 52.9+/-2.6 bursts/min in heart failure patients and 34.9+/-1.9 bursts/min in normal subjects (P<0.0001). In normal subjects, but not in heart failure patients, total power (PT) (r=-0.41; P=0.02) and fractal power (PF) (r=-0.36; P=0.04) were inversely related to age. In heart failure patients, total and fractal power were reduced (P<0.009 for both), and were inversely related to MSNA burst frequency (r=-0.55, P=0.001 and r=-0.60, P=0. 0003 respectively). In normal subjects, there was no relationship between MSNA and either PL or PH. In heart failure patients, as anticipated, PH was inversely related to MSNA (r=-0.41; P<0.02). However, PL was also inversely rather than directly related to MSNA (r=0.44 for 1/log10 PL; P<0.01). There was no relationship between other sympathetic (PL/PH) or parasympathetic (PH/PT) indices and MSNA in either heart failure patients or normal subjects. The lack of concordance between these direct and indirect estimates of sympathetic nervous system activity indicates that this component of HRV cannot be used for between-subject comparisons of central sympathetic nervous outflow. It is the absence of low-frequency power that relates most closely to sympathetic activation in heart failure.     

6β-乙酰氧基去甲托烷呼吸抑制效应

6β-乙酰氧基去甲托烷(6β-acetoxynortropane,6β-AN)是一种新型M2受体激动剂,兔10ug·kg^-1iv,犬2,5,20ug·kg^-1iv均导致呼吸频率、潮气量、每分通气量明显减少(P<0.05或0.01),呈剂量依赖关系。pO₂降低,pCO₂升高。较小剂量给兔0.5,1.0,2.0,4.0ug·kg^-1iva和犬0.25,0.5,1.0ug·kg^-1iva亦产生与静脉给药相似的呼吸抑制效应。AF-DX116能拮抗6β-AN的呼吸抑制作用,PZ则与6β-AN产生协同作用。表明6β-AN有呼吸抑制作用,并可能与其激动呼吸中枢M2受体有关。     

Arterial oxygen saturation in infants at risk of sudden death: influence of sleeping position

To study the possible influence of sleeping position on arterial oxygen saturation, measured by pulse oximetry (Sp6₂), 7–h overnight recordings of breathing movements and ECG were performed in 43 infants (median age 2.4 months, range 0.2–11 months) at increased risk of sudden infant death syndrome (SIDS). Infants were randomly allocated to start sleeping either in their usual sleeping position or in the opposite position. After 3.5 h, all infants were gently turned over. Thus, each infant served as their own control. Recordings were analysed for sleep time, baseline Sp0₂ (only during regular breathing), and the number and duration of desaturations (a decrease in Sp0₂ to ≤80%). In the prone position, a significantly higher proportion of time was spent asleep (median 79% versus 70%; p < 0.05). Median baseline Sp0₂ was 98.8% (91.7–100%) in the prone and 99.0% (92.0–100%) in the supine position (ns). A total of 191 desaturations were found in 29 recordings; 96 in the prone and 95 in the supine position (ns). One infant subsequently died of SIDS while sleeping in the prone position. He had a relatively high number of desaturations (n = 12) which all occurred in the prone position. These results confirm earlier studies which could not find a significant influence of sleeping position on baseline oxygenation. The occurrence of desaturations in the prone position only in the infant who subsequently died requires further investigation.     

木贼提取物对小鼠脑心肺过氧化脂质产生的影响

木贼水醇提取物对小鼠过氧化脂质的产生有明显抑制作用。该提取物能减少体外与体内实验小鼠脑、心、肺匀浆中MDA含量,并随剂量的增加作用增强。提示木贼水醇提取物可能具有抗衰老作用。