New report in the Journal of Leukocyte Biology suggests that zinc activates a key protein on T cells needed to fight infections 

Everyone knows that vitamins “from A to zinc” are important for good health. Now, a new research study in the August 2009 print issue of the Journal of Leukocyte Biology suggests that zinc may be pointing the way to new therapeutic targets for fighting infections. Specifically, scientists from Florida found that zinc not only supports healthy immune function, but increases activation of the cells (T cells) responsible for destroying viruses and bacteria. 

“It has been shown that zinc supplementation significantly reduces the duration and severity of childhood diarrhea, lower respiratory infections, and incidence of malaria in zinc-deficient children,” said report co-author, Robert Cousins, Ph.D., who also is the director of the Center for Nutritional Sciences within the Food Science and Human Nutrition Department at the University of Florida. “Age-related declines in immune function have also been related to zinc deficiency in the elderly.”

Scientists administered either a zinc supplement or a placebo to healthy volunteers to assess the effects of zinc on T cell activation. After isolating the T cells from the blood, scientists then simulated infection in laboratory conditions. Results showed that T cells taken from the zinc-supplemented group had higher activation than those from the placebo group. Specifically, cell activation stimulated the zinc transporter in T cells called “ZIP8,” which transports stored zinc into the cell cytoplasm where it then alters the expression of a T cell protein in a way needed to fight infections. 

“As the debate over zinc supplementation in healthy individuals continues,” said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology, “studies like this help shed light on how zinc may enhance the ability of our immune systems to fight off foreign invaders. Equally important, this work points toward new possible targets for entirely new drugs to help augment immune function and prevent or stop infections that might be resistant to traditional antibiotics.”

Reference:   Federation of American Societies for Experimental Biology, Got zinc? New zinc research suggests novel therapeutic targets, July 30, 2009

Benzene, toluene, xylene, and formaldehyde are well-known indoor air pollutants, especially after house decoration. They are also common pollutants in the working places of the plastic industry, chemical industry, and leather industry. It has been reported that these pollutants cause people to be irritated, sick, experience a headache, and be dizzy. They also have the potential to induce asthma, aplastic anemia, and leukemia, even cause abortion or fetus malformation in humans.  

In this study, the airborne toxicity of benzene, toluene, xylene, and formaldehyde to murine embryonic stem cells (mES cells) were tested using airborne exposure technique to evaluate the mES cell airborne exposure model on embryotoxicity prediction. Briefly, mES cells were cultured on Transwell inserts and were exposed to an airborne surrounding of test chemicals in a chamber for 1 h at 37 degrees C. Cytotoxicity was determined using the MTT assay after further culture for 18 h at 37 degrees C in normal medium. The airborne IC(50) (50% inhibition concentration) of benzene, toluene, xylene, and formaldehyde derived from the fitted dose-response curves were 17,400 +/- 1290, 16,000 +/- 250, 4680 +/- 500, and 620 +/- 310 ppm, respectively.  

Formaldehyde was found to be the compound most toxic to mES cells compared to benzene homologues. The toxicity data had good correlation with the in vivo data. The results showed that the mES airborne exposure model may be used to predict embryotoxicity of volatile organic compounds. 

Reference:   Shen S, Yuan L, Zeng S., An effort to test the embryotoxicity of benzene, toluene, xylene, and formaldehyde to murine embryonic stem cells using airborne exposure technique, Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China, Inhal Toxicol. 2009 Jul 27

A new study by researchers at the Georgetown’s Lombardi Comprehensive Cancer Center finds a higher level of common household pesticides in the urine of children with acute lymphoblastic leukemia (ALL), a cancer that develops most commonly between three and seven years of age. The findings are published in the August issue of the journal Therapeutic Drug Monitoring.

Researchers caution that these findings should not be seen as cause-and-effect, only that the study suggests an association between pesticide exposure and development of childhood ALL.

“In our study, we compared urine samples from children with ALL and their mothers with healthy children and their moms. We found elevated levels of common household pesticides more often in the mother-child pairs affected by cancer,” says the study’s lead investigator, Offie Soldin, PhD, an epidemiologist at Lombardi. Soldin cautions, “We shouldn’t assume that pesticides caused these cancers, but our findings certainly support the need for more robust research in this area.”

The study was conducted between January 2005 and January 2008 with volunteer participants from Lombardi and Children’s National Medical Center who live in the Washington metropolitan area. It included 41 pairs of children with ALL and their mothers (cases), and 41 pairs of healthy children and their mothers (controls). For comparison purposes, the case pairs were matched with control pairs by age, sex and county of residence. Previous studies in agricultural areas of the country have suggested a relationship between pesticides and childhood cancers, but researchers say this is the first study conducted in a large, metropolitan area.

Urine samples were collected from all child-mother pairs and analyzed by the Centers for Disease Control and Prevention to look for evidence of organophosphates (OP), the chemical name of some household pesticides. The body breaks down OP into metabolites which can be tracked in urine samples. The researchers say pesticides were detected in the urine of more than half of the participants, but levels of two common OP metobolites, diethylthiophosphate (DETP) and diethyldithiophosphate (DEDTP), were higher in the children with ALL compared to the control children (p< 0.03 and p< 0.05).

Also for the study, the mothers completed a questionnaire to collect information about the family’s exposure to pesticides, their medical history, home and neighborhood characteristics, diet, and history of smoke exposure. More case mothers (33 percent) than controls (14 percent) reported using insecticides in the home (p< 0.02), however there was no correlation found between high levels of the OP metabolites in urine and reported use of pesticides.

“We know pesticides – sprays, strips, or ‘bombs,’ are found in at least 85 percent of households, but obviously not all the children in these homes develop cancer. What this study suggests is an association between pesticide exposure and the development of childhood ALL, but this isn’t a cause-and-effect finding,” Soldin explains. “Future research would help us understand the exact role of pesticides in the development of cancer. We hypothesize that pre-natal exposure coupled with genetic susceptibility or an additional environmental insult after birth could be to blame.”

Reference:   Georgetown University Medical Center, Common household pesticides linked to childhood cancer cases in Washington area, July 28, 2009

The authors report no related financial interests. The study was funded by Lombardi’s Cancer Center Support Grant from the National Cancer Institute, and by philanthropic support from Debbie and Scott Amey.

Exposure monitoring programs have been used in the aluminum smelter industry for decades to decrease the risk of cancer from exposure to polycyclic aromatic hydrocarbons (PAHs). Biological monitoring of PAHs incorporates all routes of exposure.  

Measuring postshift urinary 1-hydroxypyrene (1OHP), a metabolite of pyrene, determines worker’s daily PAH exposures, while measuring DNA adducts reflect chronic exposures to PAHs. We reviewed the scientific literature to identify changes over time in (1) 1OHP levels, (2) DNA adduct levels, and (3) other contributing factors associated with 1OHP and DNA adduct levels in the aluminum smelter industry. No trends were observed in 1OHP and DNA adduct levels. This could be due to variable selection of study populations and poorly identified job tasks that prevent comparison of jobs across plants and times, unassessed worker exposure variability, and the impact of cumulative exposures. Thus, it cannot be demonstrated that the use of biological monitoring to estimate PAH exposures has brought about an exposure reduction in the industry.  

Future studies should be aimed at follow-up in workplaces where dermal and inhalation exposure interventions have been employed. Inconsistent findings were also observed in the analysis of CYP1A1, GSTM1, and GSTP1 polymorphisms and their effect on biomarker levels. 

Reference:   Hopf NB, Carreon T, Talaska G.,Biological markers of carcinogenic exposure in the aluminum smelter industry–a systematic review, Department of Environmental Health, University of Cincinnati, J Occup Environ Hyg. 2009 Sep;6(9):562-81.

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) in the aquatic environment: implications for the drinking water industry and global environmental health

Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) are a group of chemical compounds with diverse physical and chemical properties. Recent studies have indicated undesired effects of EDCs and PPCPs at their reported trace concentrations (ng l(-1) to microg l(-1)). 

This paper reviews the current knowledge on the sources, properties, occurrence and health impacts of EDCs and PPCPs, and their removal from drinking water using ozonation and ozone/hydrogen peroxide-based advanced oxidation. The paper also examines the potential threats posed by these chemicals to drinking water and public health. While these compounds are known to have adverse effects on ecosystem health, notably in the fish population, a similar link is yet to be established between ingestion of these compounds through drinking water and human health. In addition, data on the effectiveness of existing methods for the removal of these compounds are not conclusive.

Further studies are required to characterize risks, and also to evaluate and optimize existing removal processes. Also concerted international effort is urgent to cut down the risk of exposure and restrain the production and marketing of toxic chemicals.

Reference:  Rahman MF, Yanful EK, Jasim SY., Endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) in the aquatic environment: implications for the drinking water industry and global environmental health, Department of Civil and Environmental Engineering, The University of Western Ontario, J Water Health. 2009 Jun;7(2):224-43.