Are newborn rat-derived neural stem cells more sensitive to lead neurotoxicity?

Lead ion (Pb(2+) ) has been proven to be a neurotoxin due to its neurotoxicity on mammalian nervous system, especially for the developing brains of juveniles. However, many reported studies involved the negative effects of Pb(2+) on adult neural cells of humans or other mammals, only few of which have examined the effects of Pb(2+) on neural stem cells. The purpose of this study was to reveal the biological effects of Pb(2+) from lead acetate [Pb (CH 3 COO) 2 ] on viability, proliferation and differentiation of neural stem cells derived from the hippocampus of newborn rats aged 7 days and adult rats aged 90 days, respectively. This study was carried out in three parts. In the first part, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT viability assay) was used to detect the effects of Pb(2+) on the cell viability of passage 2 hippocampal neural stem cells after 48-hour exposure to 0-200 μM Pb(2+) . In the second part, 10 μM bromodeoxyuridine was added into the culture medium of passage 2 hippocampal neural stem cells after 48-hour exposure to 0- 200 μM Pb(2+) , followed by immunocytochemical staining with anti-bromodeoxyuridine to demonstrate the effects of Pb(2+) on cell proliferation. In the last part, passage 2 hippocampal neural stem cells were allowed to grow in the differentiation medium with 0-200 μM Pb(2+) . Immunocytochemical staining with anti-microtubule-associated protein 2 (a neuron marker), anti-glial fibrillary acidic protein (an astrocyte marker), and anti-RIP (an oligodendrocyte marker) was performed to detect the differentiation commitment of affected neural stem cells after 6 days. The data showed that Pb(2+) inhibited not only the viability and proliferation of rat hippocampal neural stem cells, but also their neuronal and oligodendrocyte differentiation in vitro. Moreover, increased activity of astrocyte differentiation of hippocampal neural stem cells from both newborn and adult rats was observed after exposure to high concentration of lead ion in vitro. These findings suggest that hippocampal neural stem cells of newborn rats were more sensitive than those from adult rats to Pb(2+) cytotoxicity.     

When can it be not optimal to adopt a new technology? A viability theory solution to a two‐stage optimal control problem of new technology adoption

Politicians often deplore economic agents’ behaviour when they do not accept new technologies. For a new technology to be adopted, the new technology value function needs to dominate the old technology value function. If this is the case, a technology switch will occur. We characterise the value functions, without computing them, using the fact that their hypographs are viability kernels of some auxiliary control problems and study whether the graphs intersect. If they do not, the corresponding value functions do not dominate each other, and the switch cannot occur at a positive time. Using this characterisation, we analyse a technology adoption problem and show how to recognise the models, for which the switch will occur at time zero or never, without solving an optimal control problem. We conclude that the current control regime may not change if the economic agents’ preferences are modelled as an integral of discounted differences between a reward from the flow variable (control) and a penalty from the stock variable (state).Copyright © 2011 John Wiley & Sons, Ltd.     

MSCs-肝细胞共培养上清对体外培养L02细胞的影响

目的以体外培养L02细胞为实验对象,了解骨髓间充质干细胞(MSCs)与肝细胞共培养上清的生物活性。方法采用两步酶分离法、全骨髓贴壁筛选法分别分离肝细胞、MSCs,按比例直接共培养,收集不同时段的共培养上清,用于人肝细胞系-L02细胞的培养。分别以单独培养的肝细胞上清、MSCs上清为对照,观察共培养上清对L02细胞活力和总蛋白合成的影响;同时观察其对L02细胞损伤模型的AST、LDH及细胞凋亡的影响。结果肝细胞上清、MSCs上清以及共培养上清对L02细胞的活力和增殖均有显著促进作用,表现为L02增殖活跃,总蛋白合成量增加;加入上述细胞上清的酒精损伤L02细胞AST、LDH释放和细胞凋亡显著低于未加细胞上清的对照组,其中共培养上清效果最为显著(P<0.05)。结论共培养上清对L02有明显的刺激增殖和损伤保护作用。     

Utility of fractional flow reserve to determine treatment after recent large myocardial infarction with severe left ventricular dysfunction

Evaluation of ischemia and the extent of viable myocardium is required prior to consideration of revascularizing a lesion after a myocardial infarction in which there is hypo‐ or akinesis. We present a case in which we utilized fractional flow reserve (FFR) of a lesion in a patient whose nuclear study 7 days after infarction suggested minimal viability in the infarct zone. After FFR was positive, stenting was performed with recovery of a large amount of viable myocardium at 1 month as shown on nuclear study. This case illustrates that if ischemia is demonstrated by FFR in an infarct‐related artery even with minimal viability by nuclear study, revascularization may result in significant myocardial recovery. © 2011 Wiley Periodicals, Inc.     

Platelet‐rich plasma protects rotator cuff‐derived cells from the deleterious effects of triamcinolone acetonide

Triamcinolone acetonide (TA) injections are widely used to treat enthesopathy, but they may induce adverse effects such as tendon impairment and rupture. Platelet‐rich plasma (PRP) is a blood fraction containing high platelet concentrations and various growth factors that play a role in tissue repair processes. The purpose of this study is to investigate whether TA has deleterious effects on human rotator cuff‐derived cells, and if PRP can protect these cells from the effects of TA. Human rotator cuff‐derived cells were cultured with and without TA and PRP, and the culture without any additive served as the control. Cell morphology was assessed at days 7 and 21. Cell viability was evaluated at days 1, 7, 14, and 21 by a water‐soluble tetrazolium salt assay. Induction of apoptosis was measured by immunofluorescence staining and flow cytometry at day 7. Induction of cleaved caspase‐3 was measured by immunofluorescence staining at day 7. The cells cultured with TA had a flattened and polygonal shape at day 7. The cells cultured with both TA and PRP were similar in appearance to control cells. Exposure to TA also significantly decreased cell viability, but cell viability did not decrease when PRP was added along with TA. The number of apoptotic cells increased with TA exposure, while addition of PRP prevented cell apoptosis. In conclusion, the deleterious effect of TA was prevented by PRP, which can be used as a protective agent for patients receiving local TA injections. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 976–982, 2013