• 主题
高级搜索  >
历史搜索 清空历史

您现在的位置：首页>美国卫生研究院文献>Toxicological Research

期刊信息

  • 期刊名称：

    -

  • 刊频： Quarterly
  • NLM标题： Toxicol Res
  • iso缩写： -
  • ISSN： -

年度选择

更多>>

  • 排序：
  • 显示：
  • 每页：
全选（0）
<14/20>
共489条结果
  • 1.

    【2hr】Subacute Oral Toxicity Study of Korean Red Ginseng Extract in Sprague-Dawley Rats

    包量

    机译 红参提取物对Sprague-Dawley大鼠的亚急性口服毒性研究
    摘要：Ginseng is a well-known traditional medicine used in Asian countries for several thousand years, and it is currently applied to medicine, cosmetics, and nutritional supplements due to its many healing and energygiving properties. It is well demonstrated that ginsenosides, the main ingredient of ginseng, produce a variety of pharmacological and therapeutic effects on central nerve system (CNS) disorders, cardiovascular disease, endocrine secretions, aging, and immune function. Korean red ginseng extract is a dietary supplement containing ginsenoside Rb1 and ginsenoside Rg1 extracted from Panax ginseng. While the pharmacokinetics and bioavailability of the extract have been well established, its toxicological properties remain obscure. Thus, four-week oral toxicity studies in rats were conducted to investigate whether Korean red ginseng extract could have a potential toxicity to humans. The test article was administered once daily by oral gavage to four groups of male and female Sprague-Dawley (SD) rats at dose levels of 0, 500, 1,000, and 2,000 mg/kg/day for four weeks. Neither deaths nor clinical symptoms were observed in any group during the experiment. Furthermore, no abnormalities in body weight, food consumption, ophthalmology, urinalysis, hematology, serum biochemistry, gross findings, organ weights, or histopathology were revealed related to the administration of the test article in either sex of any dosed group. Therefore, a target organ was not determined in this study, and the no observed adverse effect level (NOAEL) of Korean red ginseng extract was established to be 2,000 mg/kg/day.
  • 2.

    【2hr】Real-time Assay of Toxic Lead in In Vivo Living Plant Tissue

    包量

    机译 活体植物组织中有毒铅的实时分析
    摘要：A method of detecting lead was developed using square wave anodic stripping voltammetry (SWASV) with DNA-carbon nanotube paste electrode (CNTPE). The results indicated a sensitive oxidation peak current of lead on the DNA-CNTPE. The curves were obtained within a concentration range of 50 ngL−1-20 mgL−1 with preconcentration time of 100, 200, and 400 sec at the concentration of mgL−1, μgL−1, and ngL−1, respectively. The observed relative standard deviation was 0.101% (n = 12) in the lead concentration of 30.0 μgL−1 under optimum conditions. The low detection limit (S/N) was pegged at 8 ngL−1 (2.6 × 10−8 M). Results showed that the developed method can be used in real-time assay in vivo without requiring any pretreatment and pharmaceutical samples, and food samples, as well as other materials requiring water source contamination analyses.
  • 3.

    【2hr】Structural Aspects of GPCR-G Protein Coupling

    包量

    机译 GPCR-G蛋白偶联的结构方面
    • 作者：Ka Young Chung
    • 刊名：Toxicological Research
    • 2013年第3期
    摘要：G protein-coupled receptors (GPCRs) are membrane receptors; approximately 40% of drugs on the market target GPCRs. A precise understanding of the activation mechanism of GPCRs would facilitate the development of more effective and less toxic drugs. Heterotrimeric G proteins are important molecular switches in GPCR-mediated signal transduction. An agonist-activated receptor interacts with specific sites on G proteins and promotes the release of GDP from the Gα subunit. Because of the important biological role of the GPCR-G protein coupling, conformational changes in the G protein upon receptor coupling have been of great interest. One of the most important questions was the interface between the GPCR and G proteins and the structural mechanism of GPCR-induced G protein activation. A number of biochemical and biophysical studies have been performed since the late 80s to address these questions; there was a significant breakthrough in 2011 when the crystal structure of a GPCR-G protein complex was solved. This review discusses the structural aspects of GPCR-G protein coupling by comparing the results of previous biochemical and biophysical studies to the GPCR-G protein crystal structure.
  • 4.

    【2hr】Loss of Integrity: Impairment of the Blood-brain Barrier in Heavy Metal-associated Ischemic Stroke

    包量

    机译 完整性丧失：重金属相关性缺血性卒中的血脑屏障受损
    摘要：Although stroke is one of the leading causes of death and disability worldwide, preventive or therapeutic options are still limited. Therefore, a better understanding of the pathophysiological characteristics of this life-threatening disease is urgently needed. The incidence and prevalence of ischemic stroke are increased by exposure to certain types of xenobiotics, including heavy metals, suggesting the possible toxicological contribution of these compounds to the onset or aggravation of stroke. Among the potential targets, we have focused on alterations to cerebral endothelial cells (CECs), which play important roles in maintaining the functional integrity of brain tissue.
  • 5.

    【2hr】Recent Updates on Acetaminophen Hepatotoxicity: The Role of Nrf2 in Hepatoprotection

    包量

    机译 对乙酰氨基酚肝毒性的最新进展：Nrf2在保护肝脏中的作用
    摘要：Acetaminophen (APAP) known as paracetamol is the main ingredient in Tylenol, which has analgesic and anti-pyretic properties. Inappropriate use of APAP causes major morbidity and mortality secondary to hepatic failure. Overdose of APAP depletes the hepatic glutathione (GSH) rapidly, and the metabolic intermediate leads to hepatocellular death. This article reviews the mechanisms of hepatotoxicity and provides an overview of current research studies. Pharmacokinetics including metabolism (activation and detoxification), subsequent transport (efflux)-facilitating excretion, and some other aspects related to toxicity are discussed. Nuclear factor erythroid 2-related factor 2 (Nrf2)-regulated gene battery plays a critical role in the multiple steps associated with the mitigation of APAP toxicity. The role of Nrf2 as a protective target is described, and potential natural products inhibiting APAP toxicity are outlined. This review provides an update on the mechanism of APAP toxicity and highlights the beneficial role of Nrf2 and specific natural products in hepatoprotection.
  • 6.

    【2hr】Gastrointestinal Tract Abnormalities Induced by Prenatal Valproic Acid Exposure in Rat Offspring

    包量

    机译 大鼠子代产前丙戊酸暴露引起的胃肠道异常
    摘要：In-utero exposure to valproic acid (VPA) has been known as a potent inducer of autism spectrum disorder (ASD), not only in humans, but also in animals. In addition to the defects in communication and social interaction as well as repetitive behaviors, ASD patients usually suffer from gastrointestinal (GI) problems. However, the exact mechanism underlying these disorders is not known. In this study, we examined the gross GI tract structure and GI motility in a VPA animal model of ASD. On embryonic day 12 (E12), 4 pregnant Sprague-Dawley (SD) rats were subcutaneously injected with VPA (400 mg/kg) in the treatment group, and with phosphate buffered saline (PBS) in the control group; the resulting male offspring were analyzed at 4 weeks of age. VPA exposure decreased the thickness of tunica mucosa and tunica muscularis in the stomach and ileum. Other regions such as duodenum, jejunum, and colon did not show a significant difference. In high-resolution microscopic observation, atrophy of the parietal and chief cells in the stomach and absorptive cells in the ileum was observed. In addition, decreased staining of the epithelial cells was observed in the hematoxylin and eosin (H&E)-stained ileum section. Furthermore, decreased motility in GI tract was also observed in rat offspring prenatally exposed to VPA. However, the mechanism underlying GI tract defects in VPA animal model as well as the association between abnormal GI structure and function with ASD is yet to be clearly understood. Nevertheless, the results from the present study suggest that this VPA ASD model undergoes abnormal changes in the GI structure and function, which in turn could provide beneficial clues pertaining to the pathophysiological relevance of GI complications and ASD phenotypes.
  • 7.

    【2hr】Aluminum Nanoparticles Induce ERK and p38MAPK Activation in Rat Brain

    包量

    机译 铝纳米颗粒诱导大鼠脑内ERK和p38MAPK活化
    摘要：Aluminum nanoparticles (Al-NPs) are one of the most widely used nanomaterial in cosmetics and medical materials. For this reason, Al-NP exposure is very likely to occur via inhalation in the environment and the workplace. Nevertheless, little is known about the mechanism of Al-NP neurotoxicity via inhalation exposure. In this study, we investigated the effect AL-NPs on the brain. Rats were exposed to Al-NPs by nasal instillation at 1 mg/kg body weight (low exposure group), 20 mg/kg body weight (moderate exposure group), and 40 mg/kg body weight (high exposure group), for a total of 3 times, with a 24-hr interval after each exposure. Inductively coupled plasma mass spectrometry (ICP-MS) analysis indicated that the presence of aluminum was increased in a dose-dependent manner in the olfactory bulb (OFB) and the brain. In microarray analysis, the regulation of mitogen-activated protein kinases (MAPK) activity (GO: 0043405), including Ptprc, P2rx7, Map2k4, Trib3, Trib1, and Fgd4 was significantly over-expressed in the treated mice than in the controls (p = 0.0027). Moreover, Al-NPs induced the activation of ERK1 and p38 MAPK protein expression in the brain, but did not alter the protein expression of JNK, when compared to the control. These data demonstrate that the nasal exposure of Al-NPs can permeate the brain via the olfactory bulb and modulate the gene and protein expression of MAPK and its activity.
  • 8.

    【2hr】Hepatotoxicity in Rats Treated with Dimethylformamide or Toluene or Both

    包量

    机译 二甲基甲酰胺或甲苯或两者同时治疗对大鼠的肝毒性
    摘要：The effects of toluene in dimethylformamide (DMF)-induced hepatotoxicity were investigated with respect to the induction of cytochrome P-450 (CYP) and the activities of related enzymes. The rats were treated intraperitoneally with the organic solvents in olive oil (Single treatment groups: 450 [D1], 900 [D2], 1,800 [D3] mg DMF, and 346 mg toluene [T] per kg of body weight; Combined treatment groups: D1+T, D2+T, and D3+T) once a day for three days, while the control group received just the olive oil. Each group consisted of 4 rats. The activities of the xenobiotic metabolic enzymes and the hepatic morphology were assessed. The immunoblots indicated that the expression of CYP2E1 was considerably enhanced depending on the dosage of DMF and the CYP2E1 blot densities were significantly increased after treatment with both DMF and toluene, compared to treatment with DMF alone. The activities of glutathione- S-transferase and glutathione peroxidase were either decreased or remained unaltered after treatment with DMF and toluene, whereas the lipid peroxide levels were increased with increasing dosage of DMF and toluene. The liver tissue in the D3 group (1,800 mg/kg of DMF) showed signs of microvacuolation in the central vein region and a large necrotic zone around the central vein, in rats treated with both DMF (1,800 mg/kg) and toluene (D3T). These results suggest that the expression of CYP2E1 is induced by DMF and enhanced by toluene. These changes may have facilitated the accelerated formation of Nmethylformamide (NMF) from toluene, and the generated NMF may directly induce liver damage.
  • 9.

    【2hr】Anti-inflammatory Effect of Isaria sinclairii Glycosaminoglycan in an Adjuvant-treated Arthritis Rat Model

    包量

    机译 Isaria sinclairii糖胺聚糖在佐剂治疗的关节炎大鼠模型中的抗炎作用
    摘要：The anti-inflammatory effects of glycosaminoglycan (GAG) derived from Isaria sinclairii (IS) and of IS extracts were investigated in a complete Freund’s adjuvant (CFA)-treated chronic arthritis rat model. Groups of rats were treated orally with 30 mg/kg one of the following: [1] saline control, extracts of [2] water-IS, [3] methanol-IS, [4] butanol-IS, [5] ethyl acetate-IS, or [6] Indomethacin® as the positive control for a period of two weeks. The anti-paw edema effects of the individual extracts were in the following order: water-IS ex. > methanol ex. > butanol ex. > ethyl acetate ex. The water/methanol extract from I. sinclairii remarkably inhibited UV-mediated upregulation of NF-κB activity in transfected HaCaT cells. GAG as a water-soluble alcohol precipitated fraction also produced a noticeable anti-edema effect. This GAG also inhibited the pro-inflammatory cytokine levels of prostaglandin E2-stimulated lipopolysaccharide in LAW 264.7 cells, cytokine TNF-α production in splenocytes, and atherogenesis cytokine levels of vascular endothelial growth factor (VEGF) production in HUVEC cells in a dose-dependent manner. In the histological analysis, the LV dorsal root ganglion, including the articular cartilage, and linked to the paw-treated IS GAG, was repaired against CFA-induced cartilage destruction. Combined treatment with Indomethacin® (5 mg/kg) and IS GAG (10 mg/kg) also more effectively inhibited CFA-induced paw edema at 3 hr, 24 hr, and 48 hr to levels comparable to the anti-inflammatory drug, indomethacin. Thus, the IS GAG described here holds great promise as an anti-inflammatory drug in the future.
  • 10.

    【2hr】Development and Validation of a Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of ε-Acetamidocaproic Acid in Rat Plasma

    包量

    机译 液相色谱-串联质谱法测定大鼠血浆中ε-乙酰氨基己酸的方法开发与验证
    摘要：A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantification of ε-acetamidocaproic acid (AACA), the primary metabolite of zinc acexamate (ZAC), in rat plasma by using normetanephrine as an internal standard. Sample preparation involved protein precipitation using methanol. Separation was achieved on a Gemini-NX C18 column (150 mm × 2.0 mm, i.d., 3 μm particle size) using a mixture of 0.1% formic acid-water : acetonitrile (80 : 20, v/v) as the mobile phase at a flow rate of 200 μl/min. Quantification was performed on a triple quadrupole mass spectrometer employing electrospray ionization and operating in multiple reaction monitoring (MRM) and positive ion mode. The total chromatographic run time was 4.0 min, and the calibration curves of AACA were linear over the concentration range of 20~5000 ng/ml in rat plasma. The coefficient of variation and relative error at four QC levels were ranged from 1.0% to 5.8% and from −8.4% to 6.6%, respectively. The present method was successfully applied for estimating the pharmacokinetic parameters of AACA following intravenous or oral administration of ZAC to rats.
  • 11.

    【2hr】Investigation of Water Safety in Non-treated Drinking Water with Trace Toxic Metals

    包量

    机译 微量有毒金属未经处理的饮用水中水的安全性研究
    摘要：The trace toxic metal copper was assayed using mercury immobilized on a carbon nanotube electrode (MCW), with a graphite counter and a reference electrode. In this study, a macro-scale convection motor was interfaced with a MCW three-electrode system, in which a handmade MCW was optimized using cyclic- and square-wave stripping voltammetry. An analytical electrolyte for tap water was used instead of an expensive acid or base ionic solution. Under these conditions, optimum parameters were 0.09 V amplitude, 40 Hz frequency, 0.01 V incremental potential, and a 60-s accumulation time. A diagnostic working curve was obtained from 50.0 to 350 μg/L. At a constant Cu(II) concentration of 10.0 μg/L, the statistical relative standard deviation was 1.78% (RSD, n = 15), the analytical accumulation time was only 60 s, and the analytical detection limit approached 4.6 μg/L (signal/noise = 3). The results were applied to nontreated drinking water. The content of the analyzed copper using 9.0 and 4.0 μg/L standards were 8.68 μg/L and 3.96 μg/L; statistical values R2 = 0.9987 and R2 = 0.9534, respectively. This method is applicable to biological diagnostics or food surveys.
  • 12.

    【2hr】Mutagenic Assessment of Olmesartan Cilexetil by Bacterial Mutation Assay

    包量

    机译 细菌突变测定法评估奥美沙坦酯的致突变性
    摘要：Hypertension is a serious health problem due to high frequency and concomitant other diseases including cardiovascular and renal dysfunction. Olmesartan cilexetil is a new antihypertensive drug associated with angiotensin II receptor antagonist. This study was conducted to evaluate the mutagenicity of olmesartan cilexetil by bacterial reverse mutation test using Salmonella typhimurium (TA100, TA1535, TA98, and TA1537) and Escherichia coli (WP2 uvrA). At the concentrations of 0, 62, 185, 556, 1667, and 5000 μg/ plate, olmesartan cilexetil was negative in both Salmonella typhimurium and Escherichia coli regardless of presence or absence of metabolic activation system (S9 mix). These results demonstrate that olmesartan cilexetil does not induce bacterial reverse mutation.
  • 13.

    【2hr】Post-Translational Modification of Proteins in Toxicological Research: Focus on Lysine Acylation

    包量

    机译 毒理学研究中蛋白质的翻译后修饰：赖氨酸酰化作用
    • 作者：Sangkyu Lee
    • 刊名：Toxicological Research
    • 2013年第2期
    摘要：Toxicoproteomics integrates the proteomic knowledge into toxicology by enabling protein quantification in biofluids and tissues, thus taking toxicological research to the next level. Post-translational modification (PTM) alters the three-dimensional (3D) structure of proteins by covalently binding small molecules to them and therefore represents a major protein function diversification mechanism. Because of the crucial roles PTM plays in biological systems, the identification of novel PTMs and study of the role of PTMs are gaining much attention in proteomics research. Of the 300 known PTMs, protein acylation, including lysine formylation, acetylation, propionylation, butyrylation, malonylation, succinylation, and crotonylation, regulates the crucial functions of many eukaryotic proteins involved in cellular metabolism, cell cycle, aging, growth, angiogenesis, and cancer. Here, I reviewed recent studies regarding novel types of lysine acylation, their biological functions, and their applicationsin toxicoproteomics research.
  • 14.

    【2hr】Safety Evaluation of Topical Valproate Application

    包量

    机译 丙戊酸局部应用的安全性评估
    摘要：The potential role of topical valproate (VPA) in hair regrowth has been recently suggested. However, safety reports of VPA as a topical formulation are lacking. Therefore, in the present study, we investigated whether VPA causes skin irritation in humans. We first performed a cell viability test and showed that VPA did not exhibit toxicity toward HaCaT keratinocytes, fibroblasts, and RBL-3H mast cells. We then performed clinical patch test and skin irritation test through transdermal drug delivery with the help of microneedle rollers. No significant findings were obtained in the clinical patch test. In the skin irritation test, only 1 patient showed erythema at 1 hr, but the irritation reaction faded away within a few hours. Erythema and edema were not observed at 24 hr. We concluded that VPA has minimal potential to elicit skin irritation. Therefore, we consider that VPA can safely be applied to human skin.
  • 15.

    【2hr】Single Oral Dose Toxicity Study of Prebrewed Armeniacae Semen in Rats

    包量

    机译 大鼠预酿亚美尼亚精液的单次口服剂量毒性研究
    摘要：Armeniacae semen (AS) has been considered a toxic herb in the Korean medicine as it contains hydrogen cyanide and amygdalin, especially in its endocarp. Therefore, prebrewed AS that is devoid of endocarp has been traditionally used. In the present study, amygdalin content of the prebrewed AS was significantly lower (2.73 ± 0.32 μg/ml; p < 0.01) than the content in the extract that contained the endocarps (28.50 ± 6.71 μg/ml); amygdalin content corresponded to 10% of the extract in the present study. Because of single oral dose toxicity of prebrewed AS according to the recommendation of Korea Food and Drug Administration Guidelines (2009-116, 2009), which was based on single oral dose toxicity study of prebrewed AS, mortality due to toxic principles was significantly reduced. In this study, 2,000 mg/kg of prebrewed AS led to death of 1 female rat and 1 male rat at the end of 2 hr of administration. Based on these results, the 50% lethal dose in both male and female rats was determined to be 9279.5 mg/kg. Seizure, loss of locomotion, and increases in respiration and heart rate were observed as prebrewed AS treatment-related toxicological signs; these signs were restrictedly manifested in the prebrewed AS (2,000 mg/kg)-treated rats. In addition, no changes were observed in body weight, organ weight, gross features, and histopathological parameters with 2,000 mg/kg of AS in both male and female rats. These findings serve as direct evidence that amygdalin in AS is the toxic principle, which can be reduced by the traditional prebrewing method involving the exclusion of endocarp.
  • 16.

    【2hr】In Vitro Evaluation of Antimicrobial Activity of Lactic Acid Bacteria against Clostridium difficile

    包量

    机译 乳酸菌对艰难梭菌的体外抗菌活性评估
    摘要：Clostridium difficile infection (CDI) has become a significant threat to public health. Although broad-spectrum antibiotic therapy is the primary treatment option for CDI, its use has evident limitations. Probiotics have been proved to be effective in the treatment of CDI and are a promising therapeutic option for CDI. In this study, 4 strains of lactic acid bacteria (LAB), namely, Lactobacillus rhamnosus (LR5), Lactococcuslactis (SL3), Bifidobacterium breve (BR3), and Bifidobacterium lactis (BL3) were evaluated for their anti-C. difficile activity. Co-culture incubation of C. difficile (106 and 1010 CFU/ml) with each strain of LAB indicated that SL3 possessed the highest antimicrobial activity over a 24-hr period. The cell-free supernatants of the 4 LAB strains exhibited MIC50 values between 0.424 mg/ml (SL3) and 1.318 (BR3) mg/ml. These results may provide a basis for alternative therapies for the treatment of C. difficile-associated gut disorders.
  • 17.

    【2hr】Comparison between Source-induced Dissociation and Collision-induced Dissociation of Ampicillin, Chloramphenicol, Ciprofloxacin, and Oxytetracycline via Mass Spectrometry

    包量

    机译 质谱法比较氨苄青霉素，氯霉素，环丙沙星和土霉素的源诱导解离和碰撞诱导解离
    摘要：Mass spectrometry (MS) is a very powerful instrument that can be used to analyze a wide range of materials such as proteins, peptides, DNA, drugs, and polymers. The process typically involves either chemical or electron (impact) ionization of the analyte. The resulting charged species or fragment is subsequently identified by the detector. Usually, single mass uses source-induced dissociation (SID), whereas mass/mass uses collision-induced dissociation (CID) to analyze the chemical fragmentations Each technique has its own advantages and disadvantages. While CID is most effective for the analysis of pure substances, multiple- step MS is a powerful technique to get structural data. Analysis of veterinary drugs ampicillin, chloramphenicol, ciprofloxacin, and oxytetracycline serves to highlight the slight differences between SID and CID. For example, minor differences were observed between ciprofloxacin and oxytetracycline via SID or CID. However, distinct fragmentation patterns were observed for ampicllin depending on the analysis method. Both SID and CID showed similar fragmentation spectra but different signal intensities for chloramphenicol. There are several factors that can influence the fragmentation spectra, such as the collision energy, major precursor ion, electrospray mode (positive or negative), and sample homogeneity. Therefore, one must select a fragmentation method on an empirical and case-by-case basis.
  • 18.

    【2hr】Effects of Beryllium on Human Serum Immunoglobulin and Lymphocyte Subpopulation

    包量

    机译 铍对人血清免疫球蛋白和淋巴细胞亚群的影响
    摘要：To investigate the effects of short-term exposure of beryllium on the human immune system, the proportion of T-lymphocytes such as CD3+, CD4+, CD8+, CD95, and NK cells, andthe proportion of B cells and TNFα level in peripheral blood and immunoglobulins in the serum of 43 exposed workers and 34 healthy control subjects were studied. External exposure to beryllium was measured by atomic absorption spectrometer as recommended by the NIOSH analytical method 7300. T lymphocyte subpopulation analysis was carried out with flow cytometer. The working duration of exposed workers was less than 3 months and the mean ambient beryllium level was 3.4 μg/m3, 112.3 μg/m3, and 2.3 μg/m3 in molding (furnace), deforming (grinding), and sorting processes, respectively (cited from Kim et al., 2008). However, ambient beryllium level after process change was non-detectable (< 0.1 μg/m3). The number of T lymphocytes and the amount of immunoglobulins in the beryllium-exposed workers and control subjects were not significantly different, except for the total number of lymphocytes and CD95 (APO1/FAS). The total number of lymphocytes was higher in the beryllium-exposed individuals than in the healthy control subjects. Multiple logistic regression analysis showed lymphocytes to be affected by beryllium exposure (odd ratio = 7.293; p < 0.001). These results show that short-term exposure to beryllium does not induce immune dysfunction but is probably associated with lymphocytes proliferation.
  • 19.

    【2hr】Comparison of Toxicity and Deposition of Nano-Sized Carbon Black Aerosol Prepared With or Without Dispersing Sonication

    包量

    机译 有或没有分散超声处理的纳米炭黑气溶胶的毒性和沉积比较
    摘要：Nanotoxicological research has shown toxicity of nanomaterials to be inversely related to particle size. However, the contribution of agglomeration to the toxicity of nanomaterials has not been sufficiently studied, although it is known that agglomeration is associated with increased nanomaterial size. In this study, we prepared aerosols of nano-sized carbon black by 2 different ways to verify the effects of agglomeration on the toxicity and deposition of nano-sized carbon black. The 2 methods of preparation included the carbon black dispersion method that facilitated clustering without sonication and the carbon black dispersion method involving sonication to achieve scattering and deagglomeration. Male Sprague-Dawley rats were exposed to carbon black aerosols 6 hr a day for 3 days or for 2 weeks. The median mass aerodynamic diameter of carbon black aerosols averaged 2.08 μm (for aerosol prepared without sonication; group N) and 1.79 μm (for aerosol prepared without sonication; group S). The average concentration of carbon black during the exposure period for group N and group S was 13.08 ± 3.18 mg/m3 and 13.67 ± 3.54 mg/ m3, respectively, in the 3-day experiment. The average concentration during the 2-week experiment was 9.83 ± 3.42 mg/m3 and 9.08 ± 4.49 mg/m3 for group N and group S, respectively. The amount of carbon black deposition in the lungs was significantly higher in group S than in group N in both 3-day and 2-week experiments. The number of total cells, macrophages and polymorphonuclear leukocytes in the bronchoalveolar lavage (BAL) fluid, and the number of total white blood cells and neutrophils in the blood in the 2- week experiment were significantly higher in group S than in normal control. However, differences were not found in the inflammatory cytokine levels (IL-1β, TNF-α, IL-6, etc.) and protein indicators of cell damage (albumin and lactate dehydrogenase) in the BAL fluid of both group N and group S as compared to the normal control. In conclusion, carbon black aerosol generated by sonication possesses smaller nanoparticles that are deposited to a greater extent in the lungs than is aerosol formulated without sonication. Additionally, rats were narrowly more affected when exposed to carbon black aerosol generated by sonication as compared to that produced without sonication.
  • 20.

    【2hr】A Study on the Prevention of Salmonella Infection by Using the Aggregation Characteristics of Lactic Acid Bacteria

    包量

    机译 利用乳酸菌的聚集特性预防沙门氏菌感染的研究
    摘要：Salmonella is one of the major pathogenic bacteria that cause food poisoning. This study investigated whether heat-killed as well as live Lactobacillus protects host animal against Salmonella infection. Live and heat-killed Lactobacillusacidophilus was administered orally to Sprague-Dawley rats for 2 weeks before the rats were inoculated with Salmonella. Rise in body temperature was moderate in the group that was treated with heat-killed bacteria as compared to the Salmonella control group. The mean amount of feed intake and water consumption of each rat in the heat-killed bacteria group were nearly normal. The number of fecal Salmonellae was comparable between the live and the heat-killed L. acidophilus groups. This finding shows that L. acidophilus facilitates the excretion of Salmonella. Moreover, the levels of pro inflammatory cytokines, including tumor necrosis factor (TNF)-alpha and interleukin (IL)-1 beta, in the heat-killed L. acidophilus group were significantly lower when compared to the levels in the Salmonella control group. These results indicate that nonviable lactic acid bacteria also could play an important role in preventing infections by enteric pathogens such as Salmonella.
题名 作者 来源 发表时间

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号