The Amino-Functionalized Graphene Oxide Nanosheet Preparation for Enzyme Covalent Immobilization.

Enzyme immobilization has demonstrated effective means for extending protein stability and shelf life. However, current methods negatively affect the enzyme activity, particularly for application purposes. Herein, the amino functionalized graphene oxide (GO-NH2) was synthesized and used to covalently immobilize lactase. FT-IR, UV-Vis, SEM, TEM and XPS were employed to confirm and characterize the immobilized lactase. At the resulting optimal temperature, the immobilization rate achieved 61% and the immobilized lactase maintained approximately 95% of catalyst activity. Compared with the free lactase, used as a control, the immobilized lactase was significantly more stable within acidic or basic environments, higher temperature conditions and had multiple recycle use characteristics. Furthermore, the immobilized lactase had a preserved 87% activity after storage at 4 °C for 30 days, while the free lactase was almost deactivated after 20 days under the same storage conditions. This work conforms that the amino-functionalized graphene oxide is a potential support material for lactase immobilization and can be extended to use with a variety of enzymes for a number of applications.

Thyroid-disrupting effects and mechanism of thiazole-Zn-induced thyroid cell hypertrophy and hyperplasia in male Sprague-Dawley rats.

Thiazole-Zn is a systemic fungicide synthesized and developed in China that has been used for the prevention and treatment of bacterial and fungal diseases on fruits and vegetables. Thiazole-Zn is a new thyroid disruptor chemical. The purpose of this study was to clarify the thyroid-disrupting property of thiazole-Zn and the mechanism responsible for thyroid hormone (TH) biosynthesis inhibition in male rats induced by thiazole-Zn. First, the effects of different thiazole-Zn doses and exposure times on the thyroid weights, thyroid morphology and serum hormone levels of rats were investigated. The results showed that thiazole-Zn increased thyroid weights and serum thyroid-stimulating hormone (TSH) levels and induced thyroid cell hypertrophy and hyperplasia in a dose-related and time-related manner. Furthermore, measurement of thyroid radioiodine uptake in vivo in rats confirmed that thiazole-Zn inhibited active iodide uptake into the thyroid, which reduced circulating levels of serum T3 and T4. Decreases in circulating THs resulted in a compensatory increase in serum TSH levels through a negative feedback system. Subsequently, sustained excessive stimulation of the thyroid gland by TSH led to thyroid follicular cell hypertrophy and hyperplasia. In addition, thiazole-Zn increased sodium/iodide symporter (NIS) expression in the rat thyroid, and the increased NIS expression promoted and restored iodide uptake into the thyroids of rats. The risk of iodine intake inhibition by thiazole-Zn to humans, especially susceptible individuals, such as children and pregnant women, warrants additional attention.

The establishment of research regulations in military medical research institutions: practice and consideration / 中华医学科研管理杂志

Establishment and improvement of rules and regulations will benefit to the management of research institutions.A comprehensive,fair,reasonable,and workable rules and regulations are the basic guarantee for maintaining the orderly,steady,and sustainable development of the institutions.It is also help to fully mobilize the enthusiasm and creativity of all members of the institutes.In this paper,we use an example of a construction of rules and regulations in the military medical research Institutions,to analyze current information and posted suggestions on the rules and regulations formulation principles,making procedure,overall framework and main innovation for the future improvement and implementation of rules and regulations.

ICAM-1 and VCAM-1 expression in rat aortic endothelial cells after single-walled carbon nanotube exposure.

The expanded application of carbon nanotubes and increased annual production has recently sparked public interest concerning associated and potentially adverse exposure effects. As very little is known with regard to the toxicology and underlying mechanism of the phenomena termed "single-walled carbon nanotube (SWCNT) exposure", we conducted an in depth investigation of potential SWCNT effects on cell adhesion molecule gene expression within rat aortic endothelial cells (RAECs). RAEC exposure to SWCNT induced neutrophil adhesion to the endothelial monolayer via increased ICAM-1 and VCAM-1 expression. Due to NF-kappaB's fundamental involvement in the transcriptional regulation of cell adhesion molecules, we studied NF-kappaB/P65 activation in SWCNT treated RAECs, as well as GSH and LDH as determinants of oxidative stress, a condition that influences NF-kappaB activation. Resultant data indicates SWCNT exposure induces oxidative stress, thereby altering ICAM-1 and VCAM-1 expression. SWCNT induced nuclear NF-kB/P65 translocation can be inhibited by N-acetylcysteine, indicating elevated ICAM-1 and VCAM-1 expression is mediated by oxidative stress in RAECs, and may play important inflammatory roles in SWCNT-induced vascular endothelium damage.

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.

Progress in Research on Antibacterial Mechanism and Biological Safety of Silver Nanoparticles / 环境与健康杂志

The antibacterial property of silver nanoparticles has resulted in their widespread application in many fields,so the chance of silver nanoparticles exposure for human increased greatly.Thus,there is urgent need to assess the safety of such particle.So far,most toxicological studies of silver nanoparticles mainly focus on the cytotoxicity using different examination endpoint such as morphology,mitochondrial function,cell proliferation,enzyme activity,and so on.In addition,the in vitro studies on the toxicity of silver nanopoarticles are also reported,few of the study on molecule mechanism of toxicity was reported.This review provided a summary of antibacterial mechanism of silver nanoparticles and the current research situation of the safety.The future research direction of toxicological study of silver nanoparticles is also prospected based on the current knowledge.

Rat Aortic Endothelium Damage Caused by Carbon Nanotubes Exposure / 环境与健康杂志

Objective To investigate the effect of nanotubes on rat aortic endothelium damage.Methods Wistar rats were intratracheally instilled with carbon nanotubes(CNTs) at the doses of 0,3.5 and 17.5 mg/kg,and with a carbon black negative control,or a quartz positive control.The rats were euthanized after 7 or 30 days of the single treatment,the oxidative stress(GSH,O_2~-?) was determined by using biochemical kits,the expression of sICAM-1 and sVCAM-1 in serum was determined by using ELISA kits and ICAM-1 and VCAM-1 on aortic endothelium was determined with immunohischemistry.Results The content of GSH and O_2~1?in serum increased with a dose-dependent and time-dependent manner.A up-regulated expression of sICAM-1 and sVCAM-1 in serum and ICAM-1 and VCAM-1 in the aortic endothelium was seen.No vascular damage was seen in the rat treated with carbon black,in those treated with high-dose CNTs obvious inflammation was revealed.Conclusion Carbon nanotubes exposure can induce oxidative stress which may be followed by the up-regulated expression of sICAM-1 and sVCAM-1 in serum and ICAM-1 and VCAM-1 in the aortic endothelium,and then the endothelium disfunction may occur.

Oxidative Damage of Mouse Liver and Lung Protein Induced by Multi-walled Carbon Nanotube Exposure / 医学研究杂志

Objective To study the protein oxidative damage and its possible mechanism caused by multi-walled nanotubes(MWCNTS)in mice.Methods Totally 20 Kun-ming mice were divided randomly into 4 testing groups(n=5 for each group),with 0.1,0.2 and 0.4mg/ml MWCNTS suspension injected groups and saline injected group as control group.After 5 days exposure,the protein carbonyl content was measured by using spectrophotometric DNPH assay to reflect the degree of protein oxidative damage.Results The results showed that the protein carbonyl content in livers in 0.2 and 0.4mg/ml MWCNTS suspension injected groups were significantly higher than that in saline group(P

Levels of Air Particulates With Different Diameters and the Distribution of Heavy Metals in the Particulates During the Period of Heating Equipments Used / 环境与健康杂志

Objective To understand the pollution of particulate matters and the distribution of heavy metals in particulate matters. Methods Samples were collected with auto-sampling instrument for 32 consecutive days in heating period of Dec. 2003-Jan,2004, in a central area of Tianjin. The heavy metals were detected with atomic absorption spectrum, atomic fluorescence spectrum and plasma emission spectrum, 9 heavy metals were measured quantitatively. Results The rates of over standards for daily mean of TSP, IP, PM2.5 in heating period were 54.55%, 57.58%, 84.85% respectively. Content of some heavy metals such as Cd, Pb, Ni in the particulate matters were higher. Conclusion Air pollution with particulates in heating period is serious. PM2.5 carries more heavy metals than TSP and IP, so it is much more harmful to human health.

Application of Proteomic Techniques in the Field of Environmental Health / 环境与健康杂志

The meaning of proteome research,definition and technique system of proteome are summarized in this article.In the post-genome age,research on proteomics has become more and more important,because changes in proteins which are expressed by genes are the direct causes of life function disorders.Proteome is the entire complement of proteins expressed by a kind of cell,tissue or organism.Proteomic techniques mainly include two-dimensional electrophoresis,mass spectrometry and bioinformatics.In addition,the application of proteome techniques published home and abroad in the field of environmental health in recent years has also reviewed in this paper.

Determination of Oxidative DNA Molecule Damage Caused by Environmental Tobacco Smoke Side Stream / 环境与健康杂志

Objective The genotoxicty and its molecular mechanism of environmental tobacco smoke (ETS) were discussed through the oxidative DNA damage induced by environmental tobacco side_stream smoke(ETSS). Methods DNA adduct 8_hydroxydeoxyguanosine (8_OHdG) was used as a biomarker of oxidative DNA damage. The level of 8_OHdG in DNA exposed to ETSS was detected by HPLC_EC.On the molecular biological level,the biological oxidative ability of ETSS on DNA molecule was studied.Organic and inorganic components in ETSS were analyzed by GC_MS and AAS respectively. Results Particles and VOCs in ETSS could directly induce oxidative DNA damage and form 8_OHdG.It was found that there were 123 and 84 kinds of organic compounds in particles and volatile organic compounds of tobacco smoke side stream,and 7 kinds of inorganic compounds in ETSS.Some components especially quinones and polyphenols in ETS,could produce free radicals in vitro by the auto_oxidation without any biological activity systems,and with the catalytic reaction of metals,the DNA aduct 8_OHdG was produced. Conclusion It was proved that ETS had biological oxidative ability on DNA and expressed direct genotoxicity.8_OHdG was a fine biomarker of effect of oxidative DNA damage.

DNA Damage in Bone-Marrow Cells of Mice Exposed to Low Level of Gaseous Benzene / 环境与健康杂志

Objective To explore the DNA damage in the bone-marrow cells of the mice exposed to the low level of gaseous benzene. Methods 615 mice were divided into 4 groups randomly, 6 in each: the control group, benzene exposed group, group immited by L615K lymphocyte cell, group immited by L615K lymphocyte cell and benzene exposed in combination. Benzene was exposed at the level of 1 mg/m3, 6 h per day for 10 days. SCGE was used to detect the DNA damage in the bone-marrow cells of the mice. Results Compared with the control, the DNA damage were significantly severe in the other 3 groups. But the DNA damage of the group immited by L615K lymphocyte cell and benzene exposed in combination was significantly lower than that of the group immited by L615K lymphocyte cell. The spleen and liver indexes were higher in the two groups immited by L615K lymphocyte cell and immited by L615K lymphocyte cell plus benzene exposed compared with the control group. Conclusion Benzene exposure at the low level can induce the DNA damage in the bone-marrow cells of the mice, but for those lymphatic leukemia mice, benzene exposure at the low level may inhibit this kind of damage, to elucidate the mechanism, further studies needs to be done.

Effects of Gaseity Formaldehyde Exposure on Performance in Water Labyrinth and Hippocampal Neurotransmitters of Mice / 环境与健康杂志

Objective To study the effects of formaldehyde inhalation on spatial learning abilities and hippocampal neurotransmitters levels of mice, and to explore the neurotoxic mechanism. Methods Three groups of male Kunming mice were exposed to different concentrations (0, 1.34 and 4.02 mg/m3) of gaseity formaldehyde, 4 h/day, for 7 consecutive days,and their behavior when they learned to perform a water labyrinth task and hippocampal neurotransmitters levels were tested. Results There was no significant difference was seen in swimming duration among groups. While on days 5 and 7, mice in group of 4.02 mg/m3 formaldehyde exposure made notable more swimming errors (P

Pulmonary Toxicity of Three Typical Nanomaterials on Rats / 环境与健康杂志

Objective To investigate the toxic effect of lung and mechanism induced by silver nanoparticles(Nano-Ag),zinc oxide nanoparticles(Nano-ZnO)and titanium dioxide nanoparticles(Nano-TiO2) on rats.Methods Forty-two Wistar rats were divided into 7 groups randomly,including the control group,low(3.5 mg/kg) and high(17.5 mg/kg) dose groups of three nanomaterials.The rats were exposed by intratracheal instillation once two days for 5 weeks,and then killed by abdominal aorta bloodletting.The pathological examinations of rat lungs were performed,malondialdehyde(MDA),superoxide dismutase(SOD),reduced glutathione(GSH),nitrogen oxide(NO),interleukin-1(IL-1),interleukin-6(IL-6),tumor necrosis factor-?(TNF-?) and macrophage inflammatory protein(MIP-2) in bronchoalveolar lavage fluid(BALF) were detected.Results The results of histopathological analysis indicated that the fibrous tubercle,pulmonary alveoli destruction and the matrix inflammation of lung tissue appeared in the exposure groups.The activities of SOD in three kinds of nanoparticles groups(except for Nano-TiO2 subgroup) significantly decreased(P