Xing Liu

Excretion patterns of arsenic and its metabolites in human saliva and urine after ingestion of Chinese seaweed

There are no reports in scientific literature on arsenic species in human saliva after seaweed exposure. The present article reports for the first time the regular excretion patterns of arsenic in the saliva of volunteers with one-time ingestion of Chinese seaweed. Total arsenic and speciation analyses were carried out by high-performance liquid chromatography–inductively coupled plasma–mass spectrometry (HPLC-ICP-MS). Results show that the excretion time of total arsenic in saliva is a trifle earlier than that in urine, total arsenic in human saliva also shows a regular excretion pattern like that in urine within 72 h after exposure to seaweed. For speciation analysis, four species, including the major dimethylarsinic acid (DMA) species, were detected in urine prior to seaweed intake. Six species were detected in urine after seaweed ingestion, including DMA, methylarsonic acid (MMA), oxo-dimethylarsinoylethanol (oxo-DMAE), thio-dimethlyarsenoacetate (thio-DMAA), arsenite (AsIII) and arsenate (AsV). In saliva samples, three species were found before seaweed ingestion, with the major peak identified as AsIII. After consumption, the kinds of arsenic metabolites in saliva were less than those in urine. The major species was inorganic arsenic (iAs AsIII+AsV), followed by DMA, MMA and a trace amount of oxo-DMAE. Taken together, the present study suggests that saliva assay can be used as a potential tool for understanding the regular excretion pattern of total arsenic after seaweed ingestion. Whether or not it’s an efficient tool for assessing arsenic metabolites in humans exposed to seaweed requires further investigation.

The Arsenic Concentration in Saliva, Urine and Drinking Water in Endemic Arsenicosis Area in Shanyin County of Shanxi Province, China

Biological monitoring for arsenic(As) is usually based upon a determination of urine, blood, nail and hair arsenic concentration, however, saliva has been suggested as a non-invasive biological matrix for assessing exposure. To further evaluate the potential utility of saliva for arsenic biomonitoring, Atomic Fluorescence Spectrometry(AFS-230) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS) were used to evaluate the concentration of arsenic in drinking water, saliva and urine in endemic arsenicosis area in Shanyin County of Shanxi Province. The results showed that the arsenic concentration in drinking water was 0.55-720.0ug/L, and there were 66.67% samples above the arsenic level (50μg/L) of standards for drinking water quality. The median value of arsenic in drinking water was 127.22 μg/L. The salivary and urinary arsenic both can reflect the exposure of arsenic in drinking water. Additionally, there was a significant positive association of salivary arsenic compared with arsenic in drinking water (r=0.674, P<0.05)and urinary arsenic(r=0.794, P<0.05). These results demonstrated that, similar to urinary arsenic, salivary arsenic also can be used as a biomarker for assessing human exposue to arsenic.

Down-regulation of let-7 microRNA increased K-ras expression in lung damage induced by radon.

Radon has long been recognized as a human carcinogen leading to lung cancer, but the underlying mechanisms remain obscure. Recent studies have shown that the let-7 microRNA and K-ras play an important role in the development of various cancers. However, the exact role between let-7 and K-ras in radon induced lung damage has not been explored so far. In the present study, wistar rats and human bronchial epithelial (HBE) cells were long-term exposed to radon, and then alterations in histological pathology of rat lung tissue, ROS, antioxidant enzymes activities and clonogenic formation in HBE cells, as well as changes in let-7 and K-ras expression were determined to observe the adverse effects induced by radon. The results showed that long-term exposure to radon produced severe lung damage in rats, significantly increased ROS production and clonogenic formation ratios and decreased SOD activities in HBE cells. In addition, an obvious down-regulation of let-7 and up-regulation of K-ras were also revealed both in mRNA and in protein level in lung tissue of rats and HBE cells exposed to radon. Furthermore, a significant down-regulation of K-ras was then confirmed in both let-7b-3p and let-7a-2-3p transfected HBE cells. Taken together, the present results propose an involvement of let-7 microRNA and K-ras in radon induced lung damage both in vivo and in vitro, which may thus be of potential value in early diagnosis and therapy of radon-induced lung tumorgenesis.

Synergistic effect of radon and sodium arsenite on DNA damage in HBE cells.

Human epidemiological studies showed that radon and arsenic exposures are major risk factors for lung cancer in Yunnan tin miners. However, biological evidence for this phenomenon is absent. In this study, HBE cells were exposed to different concentrations of sodium arsenite, different radon exposure times, or a combination of these two factors. The results showed a synergistic effect of radon and sodium arsenite in cell cytotoxicity as determined by cell viability. Elevated intracellular ROS levels and increased DNA damage indexed by comet assay and γ-H2AX were detected. Moreover, DNA HR repair in terms of Rad51 declined when the cells were exposed to both radon and sodium arsenite. The synergistic effect of radon and sodium arsenite in HBE cells may be attributed to the enhanced DSBs and inhibited HR pathway upon co-exposure.

Oxidative DNA damage is involved in cigarette smoke-induced lung injury in rats.

ObjectiveReactive oxygen species (ROS) induced by exogenous toxicants are suggested to be involved in carcinogenesis by oxidative modification of DNA. 8-Hydroxyl-2-deoxyguanosine (8-OHdG) has been considered as a reliable biomarker for oxidative DNA damage both in vivo and in vitro studies. But the effect of smoking on oxidative damage has not yet been fully elucidated.MethodsWistar rats were exposed to cigarette smoke at concentrations of 20 and 60xa0% for 30xa0min, twice/day for 45xa0weeks. Then the histopathology of lung tissues, levels of ROS, 8-OHdG, and total antioxidant (T-AOC), expression of DNA repair enzymes, e.g. 8-oxyguaine DNA glycosylase (OGG1), and MutThomolog 1 (Oxidized Purine Nucleoside Triphosphatase, MTH1) were determined in urine, peripheral blood lymphocytes, and lung tissue.ResultsThe results showed that long-term cigarette smoke exposure can cause obvious damages of lung tissue in rats. In addition, a significant and cigarette smoke concentration-dependent increase in ROS and 8-OHdG were observed compared with the non-exposed control rats. In contrast, the expression of OGG1 and MTH1, and T-AOC levels were obviously decreased after long-term exposure to cigarette smoke.ConclusionThese findings indicate that long-term exposure to cigarette smoker increases ROS levels, decreases total antioxidant capacity, and interferes DNA repair capacity that eventually induces oxidative DNA damage, which appears to play an important role in cigarette smoke-induced lung injury in rats, and determination of 8-OHdG levels might be a useful method for monitoring oxidative damage in cigarette smokers.

The Application of Silk Fibroin in Tissue Engineering and Drug Carrier Area

In a long period, silk fibroin is applied in the biomedical area. Following the development of biotechnical, its new functions are get found and developed. From the ordinary tissue engineering frame to high grade frame with drug buffer system, exploitations of silk fibroin are constantly introduced new. In our review, we summarized the applications of silk fibroin in tissue engineering and drug carrier area.

Total arsenic and speciation analysis of saliva and urine samples from individuals living in a chronic arsenicosis area in China

BackgroundIt is generally acknowledged that the determination of harmful chemical compounds excreted into saliva is useful for assessing their exposure levels. The aim of the present study was to compare the total arsenic and its species in saliva and urine samples collected from the people residing in an arsenic-contaminated area of China and to further verify the feasibility of using salivary arsenic as a new biomarker of arsenic exposure.MethodsTotal arsenic and speciation analyses in urine and saliva samples among 70 residents exposed to arsenic from drinking water in Shanxi, China were carried out by high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP/MS).ResultsThe result showed that, total arsenic concentration in saliva was relatively lower than in urine samples, but it existed a strong positive correlation with total urinary arsenic, drinking water arsenic and different skin lesions. For arsenic metabolism analyses, AsIII, AsV, MMA, and DMA were detected in all of the urine samples with the dominating species of DMA (73.2%). Different with urinary arsenic species, most arsenic species in saliva were not methylated. The major species in saliva was iAs (AsIIIu2009+u2009AsV, 76.18%), followed by DMA (13.08%) and MMA (9.13%). And the primary methylation index (PMI), second methylation index (SMI) and proportion of the four different species (AsIII, AsV, MMA, and DMA) in saliva showed no significant positive relationship with that of in urine.ConclusionsThese findings indicated saliva may be used as a useful tool for biological monitoring of total arsenic exposure in the crowd rather than an efficient tool for assessing arsenic metabolism in human body after exposed to arsenic.

Effect of Gamma Irradiation on the Biocompatibility and Biodegradation of Silk Fibroin In Vivo

Silk fibroin has been a raw material for many artificial biomaterials for a long term, because of it good mechanical property and fantastic biocompatibility. As a natural protein, it has more excellences than other chemically synthetical materials. In present, silk fibroin is used to manufacture bone repair material, artificial blood vessel, microcapsules and so on. However, silk fibroin-based biomaterial is not good enough in biodegradation. In our research, we exposed the silk fibroin film under the gamma ray irradiation with the doses of 25kGy and 50kGy and implanted the film subsequently on the back of SD rats. At dates (7th, 14th, 28th, 56th, 84th ) after implantation, we got the tissue with the implanted film and had the pathological analysis accordingly. The results show that the immune cells infiltration and inflammation decreased within a month. And the immune reaction decreased more quickly in the 50kGy group. And cracks of the silk fibroin film appeared earlier in the 50kGy group. From above observation, it is indicated that the silk fibroin film with a higher dose had better biocompatibility than others. And the silk biodegradation was accelerated by the higher gamma ray dose. Therefore, we can conclude that the gamma ray is able to improve the biocompatibility of silk fibroin and accelerated the biodegradation of it.

Study on Biocompatibility of Post-Irradiated Silk Fibroin In Vitro

Because of the good biocompatibility, silk fibroin is widely applied in the biomedical area. However, a few of sensitive persons still have the allergic effect after receiving the recovery treatments involving the silk fibroin used. In present research, we had the SD rat dermal cells cultured on the silk fibroin film (irradiated by gamma ray with the doses of 25kGy and 50kGy) and tested the cell grown curve and proliferation activity of the cells in the silk fibroin extracts from the CCK-8 test kit. The result showed that the cells cultured on the 50kGy-irradiated film grown more quickly than that on the 25kGy-irradiated film and the control. Moreover, cells in the 50kGy-irradiated film extract had the most proliferation activity. In conclusion, the results indicated that the silk fibroin irradiated with higher gamma ray dose could stimulate the cells growth and proliferation.

Disposition of arsenic in saliva, blood and urine of Sprague-Dawley rats following repeated oral exposure to sodium arsenite

Biological monitoring for arsenic(As) was usually based upon a determination of urine and blood arsenic concentration, however, saliva had been suggested as a non-invasive biological matrix for assessing exposure. To further evaluated the potential utility of saliva for arsenic biomonitoring, Atomic Fluorescence Spectrometry(AFS-230) and Inductively Coupled Plasma Mass Spectrometer (ICP-MS) were used to evaluate the disposition of arsenic in whole blood, urine and saliva following repeated oral gavage doses of 0(control), 0.2, 2.0, 20.0 mg sodium arsenite/kg b.w. The results show that there is an obvious dose-response relationship of total arsenic concentration in blood, urine and saliva(P<0.05). Additionally, there is a significant positive association of salivary arsenic compared with blood arsenic (r=0.934, P<0.01) and urinary arsenic (r=0.960, P<0.01). These results demonstrate that the total arsenic in saliva had an obvious dose-response relationship, which can be used as a new biomarker for assessing human exposue to arsenic.