莪达夏提取物对人乳腺癌MCF-7细胞增殖的抑制作用

目的研究藏药莪达夏水提物对体外培养的人乳腺癌细胞MCF-7增殖的影响,并初步探讨其作用机制。方法采用MTT法检测不同浓度的莪达夏水提物处理MCF-7肿瘤细胞12、24、48 h后细胞的存活率,光镜下观察MCF-7细胞形态学的变化,用Annexin V-FITC/PI双染色凋亡检测试剂盒和流式细胞术分析水提物对MCF-7细胞凋亡的影响。结果莪达夏水提物对MCF-7肿瘤细胞的增殖产生抑制作用,且最高抑制率达62%,不同浓度的水提物作用细胞后可引起肿瘤细胞出现胞浆空泡和凋亡小体,低浓度的水提物处理细胞后,肿瘤细胞出现早期凋亡,随着药物浓度的增高,凋亡晚期的坏死细胞增多。结论莪达夏水提物可抑制体外培养的MCF-7乳腺癌细胞的增殖,其抑制作用与诱导肿瘤细胞凋亡的机制有关。     

藜蒿提取液对结肠癌细胞生长抑制的实验研究

目的观察藜蒿提取液对结肠癌细胞的生长抑制作用。方法 采用CCK-8法研究了不同浓度藜蒿提取液对鼠结肠癌细胞株CMT-93的生长抑制作用。结果藜蒿提取液可抑制鼠结肠癌细胞的生长,在一定范围内(125~1000μg/ml)呈剂量依赖关系。结论藜蒿提取液对鼠结肠癌细胞的生长有抑制,并且呈剂量依赖关系。     

山梨酸与山梨酸钾抑菌、抗炎效果比较

目的:测定和比较了山梨酸与山梨酸钾对几种常见食品污染微生物的抑菌活性以及抗炎性能。方法:采用微量肉汤稀释法、Griess试剂法。结果:山梨酸对表皮葡萄球菌、金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、绿脓杆菌和变形杆菌等受试细菌具有良好的抑制作用,效果强于山梨酸钾;而在抗炎方面,则效果弱于山梨酸钾。     

A type-specific blocking ELISA for the detection of infectious bronchitis virus antibody

Infectious bronchitis virus (IBV) infection has been a major threat to the poultry industry worldwide. Current commercially available ELISA kits detect group-specific antibodies; however, to understand the status of field infection, a monoclonal antibody (mAb) blocking ELISA (b-ELISA) against local IBVs was developed. The selected mAb showed specificity to Taiwan IBV strains but had no cross-reactivity with the vaccine strain H120. Using the hemagglutination inhibition (HI) test as a standard, the cut-off value, sensitivity, and specificity of a b-ELISA using this mAb were evaluated in 390 field samples. The type-specificity of detection was validated using a panel of chicken hyperimmune sera. The results showed that the b-ELISA demonstrated high sensitivity (98.0%) and specificity (97.2%) of detection. The agreement between the results of the b-ELISA and the HI test was statistically significant (Kappa = 0.95), and there was no significant difference between these two methods (McNemar p = 0.72). The b-ELISA specifically detected Taiwan IBV serotypes but not three non-Taiwan IBV serotypes nor sera against other avian pathogens. This b-ELISA provides type-specific antibody detection of local IBV strains. It has the potential to serve as a rapid and reliable diagnostic method for IBV clinical infections in the field in Taiwan.     

Interplay of neuronal processes during response inhibition: Results from a combined event-related potentials (ERPs)/transcranial magnetic stimulation (TMS) study on methylphenidate

The neuronal processes underlying response inhibition are often studied using either event-related potentials (ERPs) or by applying transcranial magnetic stimulation (TMS) to investigate excitatory and inhibitory processes in the motor system. We performed a more refined analysis of response inhibition by combining both approaches with the aim of identifying an interplay between ERPs and TMS parameters.During a go/nogo task, motor system excitability was measured using TMS single and double pulses and brain electrical activity was recorded in healthy adults (n = 14). Each participant completed two testing sessions, once on placebo and once on methylphenidate (double-blind, crossover design). Studying the effects of methylphenidate served as an example application for this combined approach.Developing regression models, inhibition-related TMS measures (e.g., short intracortical inhibition) and the contingent negative variation explained about 85% of the variance of the nogo-P3 under both MPH and placebo medication. The smaller the inhibitory effect in the motor system, the more terminal response control was required and the more resources were allocated for the evaluation of the inhibitory process, respectively, as indicated by a larger P3.Thus, an interplay between processes in the motor system (cortex) and control processes with sources in the prefrontal cortex and the anterior cingulate cortex (ACC) may take place, acting complementarily to facilitate a correct nogo-response.While ERPs rather represent initiation and monitoring of inhibitory processes and response control, motor inhibition may be best analyzed using TMS. A combined ERP/TMS analysis may allow for the development of distinct models concerning the interplay of processes involved in response inhibition.     

Functional brain changes in early Parkinson's disease during motor response and motor inhibition

Motor impairment represents the main clinical feature of Parkinson's disease (PD). Cognitive deficits are also frequently observed in patients with PD, with a prominent involvement of executive functions and visuo-spatial abilities. We used event-related functional MRI (fMRI) and a paradigm based on visual attention and motor inhibition (Go/NoGO-task) to investigate brain activations in 13 patients with early PD in comparison with 11 healthy controls. The two groups did not report behavioural differences in task performance. During motor inhibition (NoGO-effect), PD patients compared to controls showed an increased activation in the prefrontal cortex and in the basal ganglia. They also showed a reduced and less coherent hemodynamic response in the occipital cortex. These results indicate that specific cortico-subcortical functional changes, involving not only the fronto-striatal network but also the temporal-occipital cortex, are already present in patients with early PD and no clinical evidence of cognitive impairment. We discuss our findings in terms of compensatory mechanisms (fronto-striatal changes) and preclinical signs of visuo-perceptual deficits and visual hallucinations.     

纳米银医用抗菌敷料抗菌性能检测方法的研究

目的:探讨纳米银医用抗菌敷料抗菌性能检测的试验方法。方法:采用烧瓶振荡法,探讨了摇床转速和培养温度对烧瓶振荡法的影响,并进行了条件设定的优化。同时,利用优化了的烧瓶振荡法对4个批号的纳米银医用抗菌敷料产品的抗菌性能进行检测试验,并与常规抗菌性能检测方法——抑菌环试验法进行对比研究。结果:在不同转速(100,200,300 r.min-1)和不同温度(25℃、37℃)的培养条件时,振荡培养前后菌数变化的实验结果显示,在转速200 r.min-1、培养温度25℃、作用时间1 h的培养条件下,细菌在振摇前后的菌数差值符合试验限定标准(差值变化不超过10%)。通过采用上述优化的烧瓶振荡法实验条件,检测了4批纳米银医用抗菌敷料,其结果显示具有良好的抗菌性能。其中,对金黄色葡萄球菌的抑菌率分别为97%,80%,80%,90%;对白色念珠菌的抑菌率分别为91%,78%,93%,76%。试验的灵敏性较高,而抑菌环试验结果不能准确地反映出纳米银医用抗菌敷料的抗菌性能。结论:此优化条件的烧瓶振荡法能够准确检测含纳米银敷料的抗菌性能,为此类敷料产品的抗菌性能检测提供了有效的方法。     

Effects of four types of hydroxyapatite nanoparticles with different nanocrystal morphologies and sizes on apoptosis in rat osteoblasts

Hydroxyapatite nanoparticles (nano‐HAP) have been reported to cause inflammatory reactions. Here, we aimed to compare the effects of four types of nano‐HAP with different nanocrystal morphologies (short rod‐like, long rod‐like, spherical or needle‐shaped crystals) and sizes (10–20, 10–30 or 20–40 nm) on growth inhibition and apoptosis in primary cultured rat osteoblasts. The osteoblasts was treated with the four types of nano‐HAP at various concentrations (20, 40, 60, 80 or 100 mg l^?1). The nano‐HAP specific surface area was detected using the Brunauer, Emmet and Teller method. The cell growth rate was detected using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay; apoptotic alterations and the level of reactive oxygen species in osteoblasts were measured using flow cytometry; and the amounts of apoptotic p53 and cytochrome c proteins were measured using western blotting. We observed that all four types of nano‐HAP inhibited the growth of osteoblasts in a dose‐dependent manner. These nano‐HAP significantly induced apoptosis in osteoblasts. Nano‐HAP with smaller specific surface areas induced lower apoptosis rates. The needle‐shaped and the short rod‐like particles induced greater cellular injury than the spherical and long rod‐like particles, respectively. The increased apoptosis rates were accompanied by increased p53 and cytochrome c expression. These findings indicate that nano‐HAP inhibit the activity of osteoblasts and also induce the apoptosis of osteoblasts in vitro. These findings also suggest that the nano‐HAP‐induced apoptotic pathway is mediated by a mitochondrial‐dependent pathway. Moreover, the sizes, morphologies and concentrations of nano‐HAP have significant effects on the apoptotic level. Copyright © 2011 John Wiley & Sons, Ltd.     

Cholinesterase inhibition and toxicokinetics in immature and adult rats after acute or repeated exposures to chlorpyrifos or chlorpyrifos–oxon

The effect of age or dose regimen on cholinesterase inhibition (ChEI) from chlorpyrifos (CPF) or CPF–oxon (CPFO) was studied in Crl:CD(SD) rats. Rats were exposed to CPF by gavage in corn oil, rat milk (pups), or in the diet (adults) or to CPFO by gavage in corn oil. Blood CPF/CPFO levels were measured. With acute exposure, ChEI NOELs were 2 mg/kg CPF for brain and 0.5 mg/kg CPF for red blood cells (RBCs) in both age groups. In pups, ChEI and blood CPF levels were similar using either milk or corn oil vehicles. Compared to gavage, adults given dietary CPF (12 h exposure) had greater RBC ChEI, but lower brain ChEI at corresponding CPF doses, indicating an effect of dose rate. With repeated CPF exposures, ChEI NOELs were the same across ages (0.5 and 0.1 mg/kg/day for brain and RBCs, respectively). With CPFO dosing, the ChEI NOELs were 0.1 mg/kg (acute) and 0.01 mg/kg/day (repeated doses) for RBCs with no ChEI in brain at CPFO doses up to 0.5 (pup) or 10 mg/kg (adult) for acute dosing or 0.5 mg/kg/day for both ages with repeat dosing. Thus, there were no age-dependent differences in CPF ChEI via acute or repeated exposures. Pups had less ChEI than adults at comparable blood CPF levels. Oral CPFO resulted in substantial RBC ChEI, but no brain ChEI, indicating no CPFO systemic bioavailability to peripheral tissues.     

Evaluation of bisphenol A glucuronidation according to UGT1A1*28 polymorphism by a new LC-MS/MS assay

The endocrine disruptor bisphenol A (BPA) is a frequently used chemical in the manufacture of consumer products. In humans, BPA is extensively metabolized to BPA glucuronide (BPAG) by different UDP-glucuronosyltransferase (UGT) isoforms. The study has been performed with the intention to improve the accuracy of published physiologically based pharmacokinetic models and to improve regulatory risk assessments of BPA. In order to gain insight into intestine, kidney, liver, and lung glucuronidation of BPA, human microsomes of all tested organs were used. BPAG formation followed Michaelis-Menten kinetics in the intestine and kidney, but followed substrate inhibition kinetics in the liver. Human lung microsomes did not show glucuronidation activity towards BPA. While the liver intrinsic clearance was very high (857 mL min(-1)kg body weight(-1)), the tissue intrinsic clearances for the kidney and intestine were less than 1% of liver intrinsic clearance. Since BPA is a UGT1A1 substrate, we postulated that the common UGT1A1*28 polymorphism influences BPA glucuronidation, and consequently, BPA detoxification. Hepatic tissue intrinsic clearances for UGT1A1*1/*1, UGT1A1*1/*28, and UGT1A1*28/*28 microsomes were 1113, 1075, and 284 mL min(-1)kg body weight(-1), respectively. Prior to microsomal experiments, the bioproduction of BPAG and stable isotope-labeled BPAG (BPAG(d16)) was performed for the purpose of the reliable and accurate quantification of BPAG. In addition, a sensitive LC-MS/MS analytical method for the simultaneous determination of BPA and BPAG based on two stable isotope-labeled internal standards was developed and validated. In conclusion, our in vitro results show that the liver is the main site of BPA glucuronidation (K(m) 8.9 μM, V(max) 8.5 nmol min(-1) mg(-1)) and BPA metabolism may be significantly influenced by a person's genotype (K(m) 10.0-13.1 μM, V(max) 3.4-16.2 nmol min(-1) mg(-1)). This discovery may be an important fact for the currently on-going worldwide BPA risk assessments and for the improvement of physiologically based pharmacokinetic models.