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Vitamin C helps fight cancer

A new study, led by Associate Professor Margreet Vissers of the University of Otago’s Free Radical Research Group, is the first real evidence of a connection between vitamin C and tumour growth. Associate Professor Vissers says “Our results offer a promising and simple intervention to help in our fight against cancer, at the level of both prevention and cure”. The new study was published in the journal Cancer Research. The role of vitamin C in cancer treatment has been the subject of debate for many years, with many anecdotal accounts of the beneficial role of vitamin C in both the prevention and treatment of cancer. In previous studies, Associate Professor Vissers has demonstrated the vitamin’s importance in maintaining cell health and hinted at its potential for limiting diseases such as cancer. In her latest research, she investigated whether vitamin C levels were lowered in patients with endometrial tumours. The study examined whether the cancer cells had low vitamin C levels and whether this correlated with tumour aggressiveness and resistance to chemotherapy. Associate Professor Vissers and her colleagues discovered tumours were less able to accumulate vitamin C compared with normal healthy tissue, and that this related to the ability of the tumour to survive and grow. Tumours with low vitamin C levels had more of a protein called HIF-1 which allows them to thrive in conditions of stress. The findings are significant as they show, for the first time, a direct relationship between HIF-1 and vitamin C levels in tumours and suggest it would be beneficial for people with cancer cells to have more vitamin C. This could help limit the rate of tumour growth, increase the responsiveness to chemotherapy and may prevent the formation of solid tumours.

Science Alert, 19 July 2010 http://www.sciencealert.com.au
Researchers Model Personal Pollution Exposure

2010-07-27

In a new study, researchers have concluded that people’s diet, not their local environment, best determines their pollutant loads. Environmental toxicologists would like to better predict how much organic chemical pollution settles into our bodies, but two roadblocks stand in their way. Scientists don’t know the exact emission rates of these chemicals or how quickly they biodegrade in the environment. A new study sidesteps these data gaps and finds that people’s diets matter more than their local environment. Organic contaminants, such as plasticisers and pesticides, make a long, complicated trip through the environment to us. “This complexity leads to great variability in human exposure between ecosystems,” says Emma Undeman, an environmental chemist at Stockholm University in Sweden. For example, even though pollution emissions in the Arctic are very low, people who live there accumulate greater levels of harmful chemicals than people living in higher-emitting temperate regions. Undeman and her colleagues wanted to find a novel way to predict this variability that overcame toxicologists’ two roadblocks. They started by asking a question: If different ecosystems, such as the tropics or the Arctic, had identical emission levels and you compared people’s contaminant loads in each region, how would they differ? To answer their question, the scientists combined two models: one that calculates how chemicals move in an ecosystem and one that analyses how the chemicals behave in that region’s food chain. The models took into account environmental factors such as temperature and precipitation along with details about people’s diet from each region.

With their linked-up models, the researchers set pollution emission rates equal for all ecosystems and estimated a person’s average pollutant exposure in each region. They then normalised each region’s estimates to that of the temperate zone to create an exposure susceptibility index, which allowed them to rank exposures for each region. Not surprisingly, the Arctic came out on top. But the gap between the Arctic and other regions was larger than expected: A person living in the Arctic is about 520 times more susceptible to some pollutant exposures than a person eating a mixed diet in the temperate zone, the scientists estimated. Surprisingly, diet was the key factor, Undeman says. “The Arctic is a very susceptible environment because people there eat seal, which is a very good exposure vector for chemicals,” she says. Seals and other marine mammals pack a high pollutant load because they live longer and feed on predatory fish that bioaccumulate contaminants. Because vegetables sit at the bottom of the food chain and amass fewer pollutants, vegans in temperate zones were the least susceptible, the researchers concluded. Frank Wania, an environmental chemist at the University of Toronto, Scarborough in Canada and a co-author of the study, says that these calculations show that policymakers can’t take risk assessments for the well-studied temperate region and apply them elsewhere, because the risks vary by several orders of magnitude. Tom McKone, an environmental health scientist at the University of California, Berkeley, agrees that these susceptibility calculations could be powerful tools for policymakers: “It takes a complicated set of processes and integrates it into a single number that makes sense.”

Chemical & Engineering News, 22 July 2010 http://pubs.acs.org/cen/news
Technical

ENVIRONMENTAL

Investigation of selenium levels in environment and human body in Gaomi City and Zichuan District of Shandong Province in 2005

2010-07-29

Lijiaying Township in Gaomi City of Weifang City, Zhaili Township and Longquan Township in Zichuan District of Zibo City were selected. Two farming soil samples at different spot, local wheat and corn, residents nail samples from 3 to 4 families were collected in each natural village in the investigated towns. The contents of selenium were detected by 2,3-diamino naphthalene fluorescence method. In Lijiaying, selenium was deficient in soil, wheat, corn, above selenium deficiency diagnosis and below selenium-adequate level in the nail, while in Zhaili and Longquan, the selenium level in the soil, wheat, corn, nails was adequate. The external environment is selenium deficient in Lijiaying, selenium adequate in Longquan and Zhaili.

Authors: Bian, Jianchao; Yun, Zhongjie; Liu, Yuan; Song, Shuliang; Qin, Qiliang; Liu, Chuanjiao; Zhai, Naiyao; Ge, Xiangjin; Jiang, Yuting

Full Source: Zhongguo Difangbingxue Zazhi 2009, 28(4), 446-448 (China)
Predicting Changes in PM Exposure Over Time at U.S. Trucking Terminals Using Structural Equation Modelling Techniques

2010-07-29

This study analyses the temporal variability of occupational and environmental exposures to fine particulate matter in the U.S. trucking industry and tests the predictive ability of a novel multilayer statistical approach to occupational exposure modelling using structural equation modelling (SEM) techniques. For these purposes, elemental carbon mass in six U.S. trucking terminals were measured twice during the same season up to 2 years apart, observing concentrations in the indoor loading and outdoor background location as well as in the truck cabs of local drivers while on the road. There was a general trend toward higher exposures during the second sampling trips; however, these differences were statistically significant in only a few cases and were largely attributable to changes in weather patterns. Once accounting for systematic prediction errors in background concentrations, the SEM approach provided a strong fit for work-related exposures in this occupational setting.

Authors: Davis, Mary E.; Laden, Francine; Hart, Jaime E.; Garshick, Eric; Blicharz, Andrew; Smith, Thomas J.

Full Source: Journal of Occupational and Environmental Hygiene 2009, 6(7), 396-403 (USA).
Airborne enteric coliphages and bacteria in sewage treatment plants

2010-07-29

The concentrations of airborne culturable microorganisms were determined in wastewater and sludge treatment processes of seven sewage treatment plants. Two types of coliphages, Salmonella and total viable bacteria were sampled by the BioSampler and the numbers of faecal coliforms and enterococci were obtained from the Andersen 6-stage impactor. The BioSampler recovered higher numbers of airborne coliphage viruses than has been measured with other liquid samplers in previous studies, suggesting that this sampler has improved efficiency for sampling airborne coliphages. Airborne coliphages were detected in many stages of the wastewater or sludge treatment process. The highest microbiological air contaminations were found in pre-treatment and aerated grit separation stages of the operation. This was attributed to aerosolisation of microorganisms by mechanical handling or forced aeration. Aeration and settling processes located outdoors caused low microbial concentrations, but the brush aerator released more microorganisms into the air. Our results emphasise the necessity for controlling the exposure of sewage workers to airborne microorganisms, especially in process areas that involve mechanical agitation or forced aeration of wastewater.

Authors: Heinonen-Tanski, Helvi; Reponen, Tiina; Koivunen, Jari.

Full Source: Water Research 2009, 43(9), 2558-2566 (Finland).
MEDICAL

Zinc protects human peripheral blood lymphocytes from Cr(III)(phenanthroline)3-induced apoptosis

2010-07-29

The authors have studied the effect of Cr(III)(phen)3 [(tris(1,10-phenanthroline) chromium(III) chloride)] on lymphocytes in order to find out if metallothioneins (MTs) are produced in the process. The authors also investigated whether zinc pre-treatment is able to protect cells from apoptosis reported to occur for this compound. MT synthesis is induced by Cr(III)-(phen)3, and it has been identified as the MT-3 isoform through RTPCR which has not been reported earlier. By zinc pre-treatment, this apoptosis is reversed as inferred from cytotoxicity studies, Annexin-V/PI staining, ethidium bromide/acridine orange staining, and DNA fragmentation pattern and ultrastructural investigations using TEM and SEM. The zinc pre-treatment reduces the amount of ROS produced by Cr(III)(phen)3. The MT-1a and 1b synthesised by zinc is possibly able to scavenge, which is one of the early signalling molecules that lead to apoptosis. Zinc pre-treatment also reverses the changes in downstream signalling events such as mitochondrial membrane potential, ATP levels, and the activation of caspase-3. This is the first report on the induction of MT-3 in lymphocytes due to a metal stress or any other stimuli. Even though MT-3 is synthesised here, apoptosis still occurs due to ROS production on Cr(III)(phen)3 exposure when the cells have not been primed with zinc.

Authors: Sankaramanivel, Sundararaj; Rajaram, Anantanarayanan; Rajaram, Rama.

Full Source: Toxicology and Applied Pharmacology 2010, 243(3), 405-419 (India).
Evaluation of salidroside in vitro and in vivo genotoxicity

2010-07-29

It is reported that salidroside, the main component of a traditional Chinese medicine, Rhodiola rosea, has the efficacy of protecting Coxsackie virus impairment. As part of a safety evaluation on salidroside for use in the treatment of viral myocarditis, the present study evaluated potential genotoxicity of salidroside by using the standard battery of tests recommended by the State Food and Drug Administration of China. The results showed that salidroside was not genotoxic under the conditions of the reverse mutation assay, chromosomal aberrations assay, and mouse micronucleus assay conditions. The anticipated clinical dose seems to be smaller than the doses administered in the genotoxicity assays. With confirmation from further toxicity studies, salidroside would hopefully prove to be a safe anti-Coxsackie virus agent.

Authors: Zhu, Jiangbo; Wan, Xuying; Zhu, Yuping; Ma, Xili; Zheng, Yiwen; Zhang, Tianbao

Full Source: Drug and Chemical Toxicology (1977) 2010, 33(2), 220-226 (China).
Effects of industrial lead exposure on coagulation system

2010-07-29

Lead is environmental and/or occupational toxicant. It has not well known whether it has effects on coagulation system or not. Therefore, we aimed to investigate how coagulation system is affected by the level of elevated blood lead. Fifty-two occupational lead exposure patients applied with lead intoxication symptoms. Blood examples of patients were obtained for lead level, platelet count, in-vitro bleeding time, prothrombine time, partial thromboplastin time (aPTT), fibrinogen, thrombin time, protein C, protein S and antithrombin III. The patients are evaluated according to three groups as mild, moderate and severe. Mean blood lead levels were 71,15. Mean values results of primary and secondary hemostasis and physiology coagulation inhibitors tests were in normal ranges, except fibrinogen degree. Despite mean fibrinogen degree being under normal ranges, statistically significant difference between the groups was not detected. Mean aPTT and protein degrees were in normal ranges, however, compared with the mild toxicated group statistically important prolongment in aPTT and reducement in protein S degrees detected in moderate-toxicated group. As a result, although our results need suggestion by in vivo and in vitro studies, it is concluded that hemostatic parameters excluding fibrinogen were not affected by mild and moderate degree elevation of blood lead.

Authors: Mazicioglu, M. Mumtaz; Kaynar, Leylagul; Cetin, Aysun; Mumcuoglu, Haluk; Saraymen, Recep; Karadag, Ozkan Kaan.

Full Source: Erciyes Tip Dergisi 2008, 30(3), 150-156 (Turkey).
Effect of silver nanoparticles on functioning of the human body

2010-07-29

Nanotechnology is the most promising field of science for generating new application in medicine, textiles and also in the other branch of industry. Most prominent nanoproducts are nanosilver particles. Usually nanosilver particles are smaller than 100 nm and contain 20-15.000 silver atoms. Researches proved than silver in nanoscale exhibit extraordinary physical, chemical and biological properties. Due to this fact, use of nanosilver particles is becoming more and more prevalent in many fields of industry. With the widespread and usage of new technologies there is, however, connected the risk of scant insights into interaction of nanoparticles with both microorganisms and human body. Biodistribution, organ accumulation or cytotoxicity of nanosilver is only a few of many problems appears in the last research. Currently is investigated impact of nanosilver particles on respiratory system, skin and gastrointestinal tract. These are only preliminary results, but we can be certain that silver-based products should be used carefulness.

Authors: Bacciarelli, Anna; Kolodziejczyk, Marek; Rybicki, Edward.

Full Source: Barwniki, Srodki Pomocnicze 2008, 52(4), 99-113 (Poland).
OCCUPATIONAL

30 years follow up study: the dose-response relationship of asbestos exposure and asbestosis

2010-07-27

In this study, the authors investigated the dose-response relationship of asbestosis incidence in the asbestos workers. A fixed prospective cohort was established in which 338 Male exposed workers employed for at least one year in asbestos plant in 1 Jan 1972, were chosen as study cohort, and the asbestos dust concentration records of all the workplaces and the incidences of asbestosis during the past 30 years (1972-2002) were collected. The accumulative exposure amount added up to the product of the concentration and the exposure time, and the dose-response relationship between asbestos and asbestosis incidence was established by the method of life table. The maximum allowable concentration of asbestos dust was predicted as 3.9mg/m3 according to the presumption that the workers would work for 40 years and the incidence of asbestosis would be controlled under 1%. The authors concluded that the results suggest that the present hygienic standard of asbestos dust(MAC) in our country is reasonable.

Authors: Deng, Qian; Lan, Ya-jia; Wang, Mian-zhen

Full Source: Xiandai Yufang Yixue 2009, 36(11), 2027- 2028, 2032 (Ch)
Base excision repair gene polymorphisms and susceptibility of chromosomal damage of vinyl chloride monomer exposed workers in China

2010-07-27

In the present study, the authors investigated the relationship between base excision repair gene polymorphisms and susceptibility of chromosomal damage in Chinese workers exposed to vinyl chloride monomer (VCM). Cytokinesis-block micronucleus (CB-MN) test was used to detect chromosome damage in peripheral lymphocytes for 185 VCM-exposed workers. Genotypes of ADPRT Val762Ala and TDG Gly199Ser were identified by creating restriction site combined with restriction fragment length polymorphism (CRSRFLP). Genotypes of APE1 Ile64Val were identified by PCR-RFLP technique. The results demonstrated an increased risk of chromosome damage for individuals carrying TDG 199Gly/Ser + Ser/Ser genotypes compared with those carrying Gly/Gly genotype (FR ) 1.198, 95% CI: 1.026-1.397). Female workers had an increased risk of chromosome damage compared with male workers (FR ) 1.172, 95% CI: 1.004-1.366). The risk of chromosomal damage for VCM-exposed workers equal to or older than 36 years of age was 1.316 (95% CI: 1.130-1.531) times of those younger than 36 years old. The genetic polymorphisms of APE1 Ile64Val and ADPRT Val762Ala were not related to the risk of chromosomal damage. The authors concluded that VCM-exposed workers carrying TDG 199Gly/Ser + Ser/Ser genotypes tended to be more susceptible to chromosomal damage induced by VCM.

Authors: Miao, Wenbin; Wang, Wei; Qiu, Yulan; Wu, Canjun; Ji, Fang; Xia, Zhaolin

Full Source: Fudan Xuebao, Yixueban 2008, 35(2), 161-166 (Ch)
DNA damage and methylation of DNA repair gene in vinyl chloride-exposed workers

2010-07-27

This study examined the relationship between DNA damage induced by vinyl chloride monomer (VCM) exposure and the promoter methylation of O6-methylguanine-DNA methyltransferase gene MGMT as well as mismatch repair gene hMLH1. VCM exposed workers were divided into DNA damage group (72 individuals) and control group (43 individuals) according to the frequency of cytokinesis-block micronucleus. Methylation-specific PCR (MSP) was used to analyse the repair gene promoter methylation status of peripheral blood lymphocytes from VCM exposed workers. The MSP results revealed that there was no detectable promoter methylation of hMLH1 in both DNA damaged group and non-damaged group. The frequency of MGMT promoter methylation was 6.9% (5/72) in DNA damaged group and 0% in non-damaged group. The authors concluded that the results suggest that aberrant methylation of MGMT gene might occur during DNA damage, reflecting the early adverse effect induced by VCM exposure.

Authors: Liu, Jing; Wang, Wei; Qiu, Yulan; Sun, Pin; Miao, Wenbin; Wu, Fen; Xia, Zhaolin

Full Source: Fudan Xuebao, Yixueban 2008, 35(2), 190-193 (Ch)
A newly recognised occupational hazard for US electronic recycling facility workers: polybrominated diphenyl ethers

2010-07-27

In this study, the authors reviewed the industrial uses, biological effects, and evidence for health risks of polybrominated di-Ph ethers (PBDEs), including the current use of common marketed PBDE mixtures. In addition, previous data on PBDE exposure in occupational and environmental settings, including past studies in electronic recycling facilities was analysed. The study also summarises new estimates of PBDE exposure among electronic recycling facility workers, along with the recommendations for monitoring and protection of exposed workers. To describe a newly recognised US occupational health hazard, polybrominated di-Ph ether (PBDE) flame retardant exposure, to US workers at electronics recycling facilities to communicate this information to occupational medicine physicians and related health workers. Using PBDE air values reported from a California electronic recycling facility and estimates of US food, air and dust intake, electronic recycling facility workers’ PBDE exposure at this facility was estimated using multiple possible scenarios. The authors then compared these estimates to intake estimates for the US general population. Occupational PBDE study findings from China, Sweden, and Norway where elevated environmental or blood PBDE levels were detected in similar workers were reviewed. An approximately 6-fold to 33-fold increase in the electronic recycling facility workers’ PBDE exposure was estimated compared with the US general population. PBDE exposure in US electronic recycling facilities is a largely unrecognised occupational health hazard. The authors concluded that based on the results, the extent of worker exposure in the US should be better characterised and steps taken to lower levels of PBDEs in the workplace where exposure exists. Health care providers, plant safety professionals, and government agencies can play a role in recognising the problem and in decreasing worker exposure.

Authors: Schecter, Arnold; Colacino, Justin A.; Harris, T. Robert; Shah, Nirav; Brummitt, Sharon I.

Full Source: Journal of Occupational and Environmental Medicine 2009, 51(4), 435-440 (Eng)
Study on the relation between level of serum aluminium and chronic cognition impairment in aluminium electrolytic worker

2010-07-27

This study explored the status of chronic cognition impairment and its influencing factors in people with occupational exposure to aluminium. The paper adopts MMSE questionnaire to investigate general health state and status of chronic cognition impairment in 204 persons with occupational exposure to aluminium. The level of serum aluminium were measured by the graphite furnace atomic absorption spectrometry-(GF-AAS). By statistics analysis we found there were 24 occupational persons suffered chronic cognition impairment, and there was significant difference in the score of MMSE between the two groups (t)12.717, P<0.05). There was significant difference in the items of MMSE such as time orientation, place orientation, language immediate memory, attention and computation, delay recall, language repeat and verbalisation between the two groups(P<0.05, t’)3.332, 4.131, 2.387, 6.785, 3.938, 2.874 and 2.395). There was no relation between chronic cognition impairment and age, working age, education, dementia family history, head trauma history, thyropathy history and psychosis history in those people(P>0.05). There was no significant difference between the chronic cognition impairment and the level of serum aluminium(MWU)111.5, P)0.646), but there was significant difference between the level of serum aluminumg60íg / L group and <60íg / L group(ø2 ) 7.190, P<0.05). The authors concluded that occupational exposure to aluminium affects the status of chronic cognition impairment, effective measure should be taken to control the concentration of aluminium in the work place, and strengthen the health examination among those workers.

Authors: Zhai, Jin-xia; Feng, A-juan; Zhang, Junqing; Fang, Si-xin

Full Source: Xiandai Yufang Yixue 2009, 36(11), 2018-2020 (Ch)
PUBLIC HEALTH

Predictors of Serum Dioxin, Furan, and PCB Concentrations among Women from Chapaevsk, Russia

2010-07-27

Dioxins, furans, and polychlorinated biphenyls (PCBs) are persistent and bioaccumulative toxic chemicals, which are ubiquitous in the environment. In this study, the authors assessed predictors of their serum concentrations among women living in a Russian town contaminated by past industrial activity. Blood samples from 446 mothers aged 23-52 years were collected between 2003-2005 as part of the Russian Children’s Study. Serum dioxin, furan, and PCB concentrations were quantified using high-resolution gas chromatography-mass spectrometry. Potential determinants of exposure were collected through interviews. Multivariate linear regression models were used to identify predictors of serum concentrations and toxic equivalencies (TEQs). Results indicated a median total PCB concentration and total TEQs of 260 ng/g lipid and 25 pg TEQ/g lipid, respectively. In multivariate analyses, both total PCB concentrations and total TEQs increased significantly with age, residential proximity to a local chemical plant, duration of local farming, and consumption of local beef. Both decreased with longer breastfeeding, recent increases in body mass index, and later blood draw date. The authors concluded that these demography and lifestyle predictors showed generally similar associations with the various measures of serum dioxins, furans, and PCBs.

Authors: Humblet, Olivier; Williams, Paige L.; Korrick, Susan A.; Sergeyev, Oleg; Emond, Claude; Birnbaum, Linda S.; Burns, Jane S.; Altshul, Larisa; Patterson, Donald G.; Turner, Wayman E.; Lee, Mary M.; Revich, Boris; Hauser, Russ

Full Source: Environmental Science & Technology 2010, ACS ASAP (English)