A new specialization in astrocytes: glutamate- and ammonia-induced nuclear size changes.

We observed nuclear swelling in glutamate (Glu)-treated astrocytes that was concomitant with but independent of astrocytic cell swelling. We confirmed Glu-induced nuclear swelling with nuclei isolated from astrocytes. Ammonia is metabolically related to Glu and could induce a nuclear swelling in intact astrocytes but shrinkage in isolated nuclei. Other compounds such as glutamine, aspartate, taurine, glycine, and ATP did not cause any nuclear swelling in isolated nuclei of astrocytes. Surprisingly, Glu and ammonia did not induce nuclear swelling in microglia, C6, HEK 293, or Hep G2 cell lines in cultures and their isolated nuclei. The Glu- and ammonia-induced nuclear size changes appear to be a specific response of astrocytes to these two closely related metabolic compounds.

Using activated carbon nanoparticles to decrease the genotoxicity and teratogenicity of anticancer therapeutic agents.

One of the key obstacles against the success in cancer chemotherapy is the toxic and side effects of the chemotherapeutic agents. The avoidance of these toxic and side effects will greatly improve the therapeutic effects of anticancer drugs while decrease the pains of the patients. Here we show that activated carbon nanoparticles (ACNP), one of the mesoporous nanoparticles, can decrease the genotoxicity and teratogenicity of mitomycin C (MMC). To study the effects of ACNP on genotoxicity and teratogenicity of MMC, methods of PCE micronucleus test, Chinese hamster lung cell chromosome aberration experiment and rat teratogenicity were employed to observe the differences in genotoxicity and teratogenicity between ACNP-adsorbed MMC (ACNP-MMC) and free MMC. Results demonstrated that free MMC 0.16-5.0 microg/kg significantly increased the positive rate of PCE micronucleus test, the chromosome aberration rate and rat teratogenecity, but ACNP-MMC did not increased these heredity and reproduction toxicological indexes in a dose range of 0.625-10.0 microg/kg. From these results, it can be concluded that ACNP-MMC have significant effects to decrease the genotoxicity and teratogenicity effects of MMC. These results will have a considerable impact on the strategy of anticancer chemotherapy.

Responses of astrocyte to simultaneous glutamate and arachidonic acid treatment.

After cellular injury many endogenous toxins are released from injured cells and result in secondary injury. To elucidate mechanisms of such injury many of these toxins have been studied individually. However, the data obtained is only useful for reference and does not accurately represent the multifactorial situation under pathophysiological conditions. Primary astrocytic cultures were treated individually and simultaneously with two well-studied toxins, glutamate (Glu) and arachidonic acid (AA). Both are simultaneously released from neural cells during injury. Measurements of cellular protein content, intracellular water space, lactate dehydrogenase release, and malondialdehyde formation indicated that Glu and AA act through different mechanisms. Glu+AA applied together had a synergistic effect on the levels of Caspase-3 gene expression, and Bcl-2 and Hsp70 protein. Atomic force microscopy observed that Glu caused cell membrane roughness and nuclear swelling, while AA induced pores in the cell membrane and nuclear shrinkage. Glu+AA accelerated nuclear shrinkage and resulted in more serious cell damage. This study not only distinguishes the different responses of astrocytes to Glu and AA, but also provides a new view into the synergistic effect of these biochemicals; highlighting the need to be cautious in applying single factor experimental data to interpret complex physiological and pathological conditions in animals. Two or more factors may act not only on different targets but also on the same target synergistically.

The biocompatibility of carbon nanotubes / 生物医学工程学杂志

Carbon nanotubes (CNT) are well-ordered, high aspect ratio allotropes of carbon. The two main variants, namely single-walled carbon nanotubes (SWNT) and multi-walled carbon nanotubes (MWNT) both possess the characteristics of high tensile strength, ultra-light weight, and excellent chemical and thermal stability. They also possess the semi- and metallic-conductive properties. This startling array of features has led to many proposed applications in the biomedical field. However, it is only recently that information on toxicity and biocompatibility has become available. Herein is presented a review on the toxicity and biocompatibility of carbon nanotubes.

Oxidative Damage on Testicles of Male Rats Induced by Micro-nano-scale SiO_2 / 环境与健康杂志

Objective To study the oxidative damage on testis of male rats induced by micro-nano-scale SiO2. Methods Male Wistar rats were exposed to nanometer SiO2(20-40 nm) and micro-meter SiO2(1-10 ?m)by intratracheal injection once two days. The rats were killed after 5 weeks of exposure. Some indicators related to the oxidative damage in the serum and the testis were determined. Results The activity of GSH-Px and SOD in the high dose groups decreased significantly and the MDA levels increased compared to the control group;The MDA levels of nano-silicon dioxide high dose group increased in the serum. Conclusion Nano-silicon dioxide may cause lipid peroxidation in the testis with a tendency of higher toxicity than that of micro-SiO2 at the same exposed level,the detail mechanism needs further discussion.

The relations between neurite development and the subcellular structures of hippocampal neuron somata.

The relations between neurite development and the subcellular structures of the hippocampal neuron somata have been studied with atomic force microscopy (AFM). The conformation of the neuron was achieved by the synapse-like structures found by AFM scanning along a neurite of the cell. Hippocampal neuron somata were divided into two or three subcellular parts by one or two horizontal grooves. The upper parts increased while the middle and the lower parts decreased with the number and the length of the neurites and the formation of the neurosynapse-like structures. When neurites sufficiently developed, the middle parts were lost and the lower parts became very small. Mitosis inhibitors could prevent the formation of such subcellular structures of hippocampal neuron somata, which was accompanied by the loss of ability to form synapse-like structures. These results suggest that the upper parts are responsible for neuritogenesis while the middle and the lower parts only have indirect effect on it.

Anti-neoplastic Effect of Xuezhikang in vitro / 中医杂志

Objective To study the anti-neoplastic effect of Xuezhikang (Regulate blood-fat) Capsule in vitro and its influence on the chemotherapeutic drug 5 Fluorouracil (5-Fu).Methods Using MTT method to measure the inhibition rate of Xuezhikang Capsule used simply,5-Fu used simply and Xuezhikang Capsule with 5-Fu together on HepG2,MCF-7 and HL-60 cells.Results The inhibitory action of Xuezhikang Capsule(2.56,0.64,0.16,0.04,0.01 mg/ml) on HepG2,MCF-7 and HL-60 cells was dose-dependent and the IC50 was 14.057,19.859 and 27.771mg/ml respectively.The inhibition ratio of five different doses of Xuezhikang Capsule(0.64,0.16,0.04,0.01,0.0025 mg/ml) with 5-Fu (0.24mg/ml) together all remarkably higher than that of 5-Fu used simply.Conclusion Xuezhikang Capsule has a significant anti-cancer effect in vitro and can enhance remarkably the anti-neoplastic effect of 5-Fu.

The influence of anisodamine on the cerebral blood flow in uncompletely ischemic rat brains / 中国药理学通报

The influence of anisodamine on the cerebral blood flow in the uncompletely ischemic brains was studied with radioactive biomicrosphere assay. After the bilateral carotid arteries were occluded the cerebral blood flow drawmatically decreased and middle part of the hemisphere had the most severe reduction. Anisodamine 10mg ? kg-1 iv selectively increased the cerebral blood flow in this area and 20mg ? kg-1 increased that in the whole hemisphere. When it was used in the dose of 40mg ? kg-, the increasing effect on the cerebral blood flow became weaker. While the cerebral blood flow decreased, the myocardial blood flow increased significantly after bilateral carotid artery occlusion. Anisodamine 20mg ? kg-1 iv made it further increase and 40mg ? kg-1 iv made it decrease. The cardiac index was not influenced by bilateral carotid artery occlusion and anisodamine 10~20mg ? kg-1 iv, but was significanntly increased by anisodamine 40mg ? kg-1 iv. These results suggested that anisodamine may be used in the treatment of ischemic cerebral diseases and should be used in different doses according to different purposes.