International Journal of Environmental Research and Public Health

120 KiB

Open AccessArticle

Assessment of Individual and Combined Toxicities of Four Non-Essential Metals (As, Cd, Hg and Pb) in the Microtox Assay

by Ali B. Ishaque, Linda Johnson, Tonya Gerald, Dwayne Boucaud, Joseph Okoh and Paul B. Tchounwou

Int. J. Environ. Res. Public Health 2006, 3(1), 118-120; https://doi.org/10.3390/ijerph2006030014 - 31 Mar 2006

Cited by 53 | Viewed by 12301

Abstract

Although most researches with non-essential metals (NEMs) have been done with single or individual metals, in reality, organisms are often exposed to multiple contaminants at the same time through the air, food and water. In this study, we tested the toxicity of four [...] Read more.

Although most researches with non-essential metals (NEMs) have been done with single or individual metals, in reality, organisms are often exposed to multiple contaminants at the same time through the air, food and water. In this study, we tested the toxicity of four NEMs, As, Cd, Pb, and Hg, individually and as a composite mixture using the microtox bioassay. This assay uses the reduction of bioluminescence of the bacterium Vibrio fischeri as a measure of toxicity. The concentrations of each chemical in the mixture were based on multiples of their maximum contaminant levels (MCLs) set by the U.S. EPA. The highest concentration of exposure was 20 times the MCL, which translated into 200, 100, 40 and 300 ppb for As, Cd, Hg and Pb, respectively. The ratio for the mixture from these concentrations was 10:5:2:15 for As, Cd, Hg and Pb, respectively. Among the individual metals tested, the ranking of toxicity was Hg>Pb>Cd>As based on the EC50 values of 109, 455, 508 and 768 ppb for Hg, Pb, Cd and As, respectively. The EC50 for the composite mixture was 495% MCL which translated into nominal concentrations of 49, 25, 10 and 74 ppb for As, Cd, Hg, and Pb, respectively. Overall, the EC50 value of each NEM within the mixture was lower than the EC50 of the individual chemical; an evidence of synergism for the mixture. The individual toxic units (TU) were 0.06, 0.05, 0.09, and 0.16 for As, Cd Hg, and Pb, respectively and the summed toxic unit (TU) was 0.37 (less than 1). This study provides needed scientific data necessary for carrying out complete risk assessment of As, Cd, Hg, and Pb mixtures of some priority compounds. Full article

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139 KiB

Open AccessArticle

The Impact of Rainfall on Fecal Coliform Bacteria in Bayou Dorcheat (North Louisiana)

by Dagne D. Hill, William E. Owens and Paul B. Tchounwou

Int. J. Environ. Res. Public Health 2006, 3(1), 114-117; https://doi.org/10.3390/ijerph2006030013 - 31 Mar 2006

Cited by 25 | Viewed by 10656

Abstract

Fecal coliform bacteria are the most common pollutant in rivers and streams. In Louisiana, it has been reported that 37% of surveyed river miles, 31% of lakes, and 23% of estuarine water had some level of contamination. The objective of this research was [...] Read more.

Fecal coliform bacteria are the most common pollutant in rivers and streams. In Louisiana, it has been reported that 37% of surveyed river miles, 31% of lakes, and 23% of estuarine water had some level of contamination. The objective of this research was to assess the effect of surface runoff amounts and rainfall amount parameters on fecal coliform bacterial densities in Bayou Dorcheat in Louisiana. Bayou Dorcheat has been designated by the Louisiana Department of Environmental Quality as a waterway that has uses such as primary contact recreation, secondary contact recreation, propagation of fish and wildlife, agriculture and as being an outstanding natural resource water. Samples from Bayou Dorcheat were collected monthly and analyzed for the presence of fecal coliforms. Fecal coliforms isolated from these samples were identified to the species level. The analysis of the bacterial levels was performed following standard test protocols as described in Standard Methods for the Examination of Water and Wastewater. Information regarding the rainfall amounts and surface runoff amounts for the selected years was retrieved from the Louisiana Office of State Climatology. It was found that a significant increase in the fecal coliform numbers may be associated with average rainfall amounts. Possible sources of elevated coliform counts could include sewage discharges from municipal treatment plants and septic tanks, storm water overflows, and runoff from pastures and range lands. It can be concluded that nonpoint source pollution that is carried by surface runoff has a significant effect on bacterial levels in water resources. Full article

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Open AccessArticle

Prevalence of Escherichia coli O157:H7 Bacterial Infections Associated With the Use of Animal Wastes in Louisiana for the Period 1996-2004

by Dagne D. Hill, William E. Owens and Paul B. Tchounwou

Int. J. Environ. Res. Public Health 2006, 3(1), 107-113; https://doi.org/10.3390/ijerph2006030012 - 31 Mar 2006

Cited by 4 | Viewed by 9496

Abstract

Animal waste from dairy and poultry operations is an economical and commonly used fertilizer in the state of Louisiana. The application of animal waste to pasture lands not only is a source of fertilizer, but also allows for a convenient method of waste [...] Read more.

Animal waste from dairy and poultry operations is an economical and commonly used fertilizer in the state of Louisiana. The application of animal waste to pasture lands not only is a source of fertilizer, but also allows for a convenient method of waste disposal. The disposal of animal wastes on land is a potential non-point source of water degradation. Human health is a major concern when considering the disposal of large quantities of animal waste. Health concerns could exist from exposure to pathogens and excess nitrogen associated with this form of pollution. The objective of this study was to collect and analyze health data related to Escherichia coli O157:H7 bacterial infections associated with the use of animal waste in Louisiana for the years 1996-2004. An analysis of adverse health effects associated with the use of animal waste in Louisiana was conducted based on the incidence/prevalence rate for the studied years. The number of reported cases increased during the summer months. Analysis of health data of the studied years showed that the number of reported disease cases of E. coli O157:H7 were highest among Caucasian infants in the 0-4 year old age category and in Caucasian children in the 5-9 year old age category. Although the number of cases declined with age, a slight increase in rates was seen among the elderly population. While the rate of reported cases per 100,000 people remained the same for the years of 1999 and 2000, the rate decreased by 60% from the year 2000 to 2001. A slight decline of the number of cases that was also reported for the years 2002 and 2003. The high rate of identification in the younger population may result from the prompt seeking of medical care when symptoms become evident among infants and young children as well as the frequent ordering of stool examination when symptoms become evident in this population group. It was also noted that areas that had a higher number of reported cases also had a greater number of physicians per 100,000 people within the parish. The association with increasing age could be attributed to declining health and weaker immune systems often found among the older population. It was concluded that although some of the studied parishes surveyed had large amounts of animal waste generated each year, statistics did not show a correlation with Escherichia coli O157:H7 bacterial infections. Full article

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Open AccessArticle

GIS and Remote Sensing Applications in the Assessment of Change within a Coastal Environment in the Niger Delta Region of Nigeria

by Yaw A. Twumasi and Edmund C. Merem

Int. J. Environ. Res. Public Health 2006, 3(1), 98-106; https://doi.org/10.3390/ijerph2006030011 - 31 Mar 2006

Cited by 42 | Viewed by 19204

Abstract

In the last decades, the Niger Delta region has experienced rapid growth in population and economicv activity with enormous benefits to the adjacent states and the entire Nigerian society. As the region embarks upon an unprecedented phase of economic expansion in the 21 [...] Read more.

In the last decades, the Niger Delta region has experienced rapid growth in population and economicv activity with enormous benefits to the adjacent states and the entire Nigerian society. As the region embarks upon an unprecedented phase of economic expansion in the 21^st century, it faces several environmental challenges fuelled partly by the pressures caused by human activities such as oil and gas exploration, housing development, and road construction for transportation, economic development and demographic changes. This continued growth has resulted in environmental problems such as coastal wetland loss, habitat degradation, and water pollution, gas flaring, destruction of forest vegetation as well as a host of other issues. This underscores the urgent need to design new approaches for managing remote costal resources in sensitive tropical environments effectively in order to maintain a balance between coastal resource conservation and rapid economic development in developing countries for sustainability. Notwithstanding previous initiatives, there have not been any major efforts in the literature to undertake a remote sensing and GIS based assessment of the growing incidence of environmental change within coastal zone environments of the study area. This project is an attempt to fill that void in the literature by exploring the applications of GIS and remote sensing in a tropical coastal zone environment with emphasis on the environmental impacts of development in the Niger Delta region of Southern Nigeria. To deal with some of the aforementioned issues, several research questions that are of great relevance to the paper have been posed. The questions include, Have there been any changes in the coastal environment of the study area? What are the impacts of the changes? What forces are responsible for the changes? Has there been any major framework in place to deal with the changes? The prime objective of the paper is to provide a novel approach for assessing the state of coastal environments while the second objective seeks a contribution to the literature. The third objective is to provide a decision support tool for coastal resource managers in the assessment of environmental impacts of development in tropical areas. The fourth objective is to assess the extent of change in a tropical ecosystem with the latest advances in geo-spatial information technologies and methods. In terms of methodology, the paper draws from primary and census data sources analyzed with descriptive statistics, GIS techniques and remote sensing. The sections in the paper consist of a review of the major environmental effects and factors associated with the problem: initiatives and mitigation measures. The project offers some recommendations as part of the conservation strategies. In spite of concerted efforts by managers to address the problems, results revel that the study area experienced some significant changes in its coastal environments. These changes are attributed to socio-economic and environmental variables. Full article

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Open AccessArticle

Assessment of Public Health Risks Associated with Atmospheric Exposure to PM_2.5 in Washington, DC, USA

by Natasha A. Greene and Vernon R. Morris

Int. J. Environ. Res. Public Health 2006, 3(1), 86-97; https://doi.org/10.3390/ijerph2006030010 - 31 Mar 2006

Cited by 102 | Viewed by 13678

Abstract

In this research, we investigated the public health risks associated with atmospheric exposure to PM_2.5 for different subpopulations (black, white, Hispanic, youth, adults, and elderly) in the Washington, DC area. Washington, DC has long been considered a non-healthy place to live according [...] Read more.

In this research, we investigated the public health risks associated with atmospheric exposure to PM_2.5 for different subpopulations (black, white, Hispanic, youth, adults, and elderly) in the Washington, DC area. Washington, DC has long been considered a non-healthy place to live according to the American Lung Association due to its poor air quality. This recognition clearly includes the negative PM-related human health effects within the region. Specifically, DC fine particulate matter (PM_2.5) [or particulate matter with an aerodynamic diameter less than 2.5 μm] poses notable health risks to subpopulations having an annual mean value of 16.70 μg/m³ during the years 1999-2004, exceeding the EPA National Ambient Air Quality Standard (NAAQS) of 15 μg/m³. Incessant exposure to significant levels of PM has previously been linked to deleterious health effects, such as heart and lung diseases. The environmental quality and public health statistics of Washington, DC indicate the need for higher-resolution measurements of emissions, both spatially and temporally, and increased analysis of PM-related health effects. Our findings show that there are significant risks of ward-specific pediatric asthma emergency room visits (ERV). Results also illustrate lifetime excess lung cancer risks, exceeding the 1x10^-6 threshold for the measured levels of particulate matter and heavy metals (chromium and arsenic) on behalf of numerous subpopulations in the DC selected wards. Full article

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Open AccessArticle

Risk Assessment and Community Participation Model for Environmental Asthma Management in an Elementary Public School: A Case Study in Puerto Rico

by Samarys Seguinot-Medina and Alberto Rivera-Rentas

Int. J. Environ. Res. Public Health 2006, 3(1), 76-85; https://doi.org/10.3390/ijerph2006030009 - 31 Mar 2006

Cited by 4 | Viewed by 12456

Abstract

Asthma is a rapidly growing chronic disease in the general population of the world, mostly in children. Puerto Ricans have the highest prevalence of children with asthma among the Hispanic community in the US and its territories. Asthma and air quality are becoming [...] Read more.

Asthma is a rapidly growing chronic disease in the general population of the world, mostly in children. Puerto Ricans have the highest prevalence of children with asthma among the Hispanic community in the US and its territories. Asthma and air quality are becoming a significant and potentially costly public health issue in Puerto Rico. The CDC has reported that in Puerto Rico, 320,350 adults have asthma and this number represents 11.5% of the island adult population. The north east municipality of Carolina, Puerto Rico, has the highest asthma prevalence in the 0 to 17 year old range (2001 data). In this study, we address the potential relationship between anthropogenic and naturally occurring environmental factors, and asthma prevalence in an urban elementary public school in Carolina in an effort to empower and engage communities to work on their environmental health issues. We integrated geographic information systems (GIS) data of anthropogenic activities near the school as well as the natural resources and geomorphology of the region. We found that as Carolina is close by to Caribbean National Forest (El Yunque), this together with the temperature and precipitation cycles in the zone creates the ideal environmental conditions for increased humidity and pollen, mold and fungi development through out the year. We also collected health and socio economic data to generate an asthma profile of the students, employees and parents from the school community, and through a survey we identified perceptions on environmental asthma triggers, and indoor air quality in the school and homes of the students and employees. Finally, we implemented a workshop on indoor air quality designed to engage the school community in managing asthma triggers and the school environment. Our results showed that nearly 30 % of its student’s population has asthma, and from this group 58% are males and 42% are female students. Of all asthmatic children, only 43% receive treatment for the disease. The study also showed that most asthmatic children are between 7 and 9 year old, and live in households with an annual income below $10,000. It also showed that 25 % of the student’s parents have the condition, and that 25% of the employees are also affected by this chronic condition. All these numbers are significantly higher than those reported by the CDC for Puerto Rico. The perception component had a response of 83% of school employees, and a 39% response from parents. It showed that people know asthma as a disease but many can’t identify most environmental asthma triggers. Pre and post tests of the workshop protocol showed that before the activity only 21% of participants can identify asthma triggers. At the end of the workshop nearly 80% were able to identify and manage environmental asthma triggers. This work validates the fact that Puerto Rico continues to have a significant number of people with asthma, particularly children asthma, and that schools are an important settings to create community based action plans to manage environmental asthma triggers through outreach and training. Full article

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Open AccessArticle

Chemical or Biological Terrorist Attacks: An Analysis of the Preparedness of Hospitals for Managing Victims Affected by Chemical or Biological Weapons of Mass Destruction

by Russell L. Bennett

Int. J. Environ. Res. Public Health 2006, 3(1), 67-75; https://doi.org/10.3390/ijerph2006030008 - 31 Mar 2006

Cited by 48 | Viewed by 13153

Abstract

The possibility of a terrorist attack employing the use of chemical or biological weapons of mass destruction (WMD) on American soil is no longer an empty threat, it has become a reality. A WMD is defined as any weapon with the capacity to [...] Read more.

The possibility of a terrorist attack employing the use of chemical or biological weapons of mass destruction (WMD) on American soil is no longer an empty threat, it has become a reality. A WMD is defined as any weapon with the capacity to inflict death and destruction on such a massive scale that its very presence in the hands of hostile forces is a grievous threat. Events of the past few years including the bombing of the World Trade Center in 1993, the Murrah Federal Building in Oklahoma City in 1995 and the use of planes as guided missiles directed into the Pentagon and New York’s Twin Towers in 2001 (9/11) and the tragic incidents involving twentythree people who were infected and five who died as a result of contact with anthrax-laced mail in the Fall of 2001, have well established that the United States can be attacked by both domestic and international terrorists without warning or provocation. In light of these actions, hospitals have been working vigorously to ensure that they would be “ready” in the event of another terrorist attack to provide appropriate medical care to victims. However, according to a recent United States General Accounting Office (GAO) nationwide survey, our nation’s hospitals still are not prepared to manage mass causalities resulting from chemical or biological WMD. Therefore, there is a clear need for information about current hospital preparedness in order to provide a foundation for systematic planning and broader discussions about relative cost, probable effectiveness, environmental impact and overall societal priorities. Hence, the aim of this research was to examine the current preparedness of hospitals in the State of Mississippi to manage victims of terrorist attacks involving chemical or biological WMD. All acute care hospitals in the State were selected for inclusion in this study. Both quantitative and qualitative methods were utilized for data collection and analysis. Six hypotheses were tested. Using a questionnaire survey, the availability of functional preparedness plans, specific preparedness education/training, decontamination facilities, surge capacity, pharmaceutical supplies, and laboratory diagnostic capabilities of hospitals were examined. The findings revealed that a majority (89.2%) of hospitals in the State of Mississippi have documented preparedness plans, provided specific preparedness education/training (89.2%), have dedicated facilities for decontamination (75.7%), and pharmaceutical plans and supplies (56.8%) for the treatment of victims in the event of a disaster involving chemical or biological WMD. However, over half (59.5%) of the hospitals could not increase surge capacity (supplies, equipment, staff, patient beds, etc.) and lack appropriate laboratory diagnostic services (91.9%) capable of analyzing and identifying WMD. In general, hospitals in the State of Mississippi, like a number of hospitals throughout the United States, are still not adequately prepared to manage victims of terrorist attacks involving chemical or biological WMD which consequently may result in the loss of hundreds or even thousands of lives. Therefore, hospitals continue to require substantial resources at the local, State, and national levels in order to be “truly” prepared. Full article

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Open AccessArticle

Combustion-Generated Nanoparticulates in the El Paso, TX, USA / Juarez, Mexico Metroplex: Their Comparative Characterization and Potential for Adverse Health Effects

by L. E. Murr, K. F. Soto, K. M. Garza, P. A. Guerrero, F. Martinez, E. V. Esquivel, D. A. Ramirez, Y. Shi, J. J. Bang and J. Venzor, III

Int. J. Environ. Res. Public Health 2006, 3(1), 48-66; https://doi.org/10.3390/ijerph2006030007 - 31 Mar 2006

Cited by 47 | Viewed by 11360

Abstract

In this paper we report on the collection of fine (PM1) and ultrafine (PM0.1), or nanoparticulate, carbonaceous materials using thermophoretic precipitation onto silicon monoxide/formvar-coated 3 mm grids which were examined in the transmission electron microscope (TEM). We characterize and compare diesel particulate matter [...] Read more.

In this paper we report on the collection of fine (PM1) and ultrafine (PM0.1), or nanoparticulate, carbonaceous materials using thermophoretic precipitation onto silicon monoxide/formvar-coated 3 mm grids which were examined in the transmission electron microscope (TEM). We characterize and compare diesel particulate matter (DPM), tire particulate matter (TPM), wood burning particulate matter, and other soot (or black carbons (BC)) along with carbon nanotube and related fullerene nanoparticle aggregates in the outdoor air, as well as carbon nanotube aggregates in the indoor air; and with reference to specific gas combustion sources. These TEM investigations include detailed microstructural and microdiffraction observations and comparisons as they relate to the aggregate morphologies as well as their component (primary) nanoparticles. We have also conducted both clinical surveys regarding asthma incidence and the use of gas cooking stoves as well as random surveys by zip code throughout the city of El Paso. In addition, we report on short term (2 day) and longer term (2 week) in vitro assays for black carbon and a commercial multiwall carbon nanotube aggregate sample using a murine macrophage cell line, which demonstrate significant cytotoxicity; comparable to a chrysotile asbestos nanoparticulate reference. The multi-wall carbon nanotube aggregate material is identical to those collected in the indoor and outdoor air, and may serve as a surrogate. Taken together with the plethora of toxic responses reported for DPM, these findings prompt concerns for airborne carbonaceous nanoparticulates in general. The implications of these preliminary findings and their potential health effects, as well as directions for related studies addressing these complex issues, will also be examined. Full article

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Open AccessArticle

The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

by J. Herkovits, J. L. D´Eramo and O. Fridman

Int. J. Environ. Res. Public Health 2006, 3(1), 43-47; https://doi.org/10.3390/ijerph2006030006 - 31 Mar 2006

Cited by 4 | Viewed by 9109

Abstract

The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m² was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that [...] Read more.

The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m² was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m² at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. Full article

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Open AccessArticle

Mercury-Induced Externalization of Phosphatidylserine and Caspase 3 Activation in Human Liver Carcinoma (HepG₂) Cells

by Dwayne J. Sutton and Paul B. Tchounwou

Int. J. Environ. Res. Public Health 2006, 3(1), 38-42; https://doi.org/10.3390/ijerph2006030005 - 31 Mar 2006

Cited by 17 | Viewed by 8931

Abstract

Apoptosis arises from the active initiation and propagation of a series of highly orchestrated specific biochemical events leading to the demise of the cell. It is a normal physiological process, which occurs during embryonic development as well as in the maintenance of tissue [...] Read more.

Apoptosis arises from the active initiation and propagation of a series of highly orchestrated specific biochemical events leading to the demise of the cell. It is a normal physiological process, which occurs during embryonic development as well as in the maintenance of tissue homeostasis. Diverse groups of molecules are involved in the apoptosis pathway and it functions as a mechanism to eliminate unwanted or irreparably damaged cells. However, inappropriate induction of apoptosis by environmental agents has broad ranging pathologic implications and has been associated with several diseases including cancer. The toxicity of several heavy metals such as mercury has been attributed to their high affinity to sulfhydryl groups of proteins and enzymes, and their ability to disrupt cell cycle progression and/or apoptosis in various tissues. The aim of this study was to assess the potential for mercury to induce early and late-stage apoptosis in human liver carcinoma (HepG₂) cells. The Annexin-V and Caspase 3 assays were performed by flow cytometric analysis to determine the extent of phosphatidylserine externalization and Caspase 3 activation in mercury-treated HepG₂ cells. Cells were exposed to mercury for 10 and 48 hours respectively at doses of 0, 1, 2, and 3 μg/mL based on previous cytotoxicity results in our laboratory indicating an LD₅₀ of 3.5 ± 0.6 μg/mL for mercury in HepG₂ cells. The study data indicated a dose response relationship between mercury exposure and the degree of early and late-stage apoptosis in HepG₂cells. The percentages of cells undergoing early apoptosis were 0.03 ± 0.03%, 5.19 ± 0.04%, 6.36 ± 0.04%, and 8.84 ± 0.02% for 0, 1, 2, and 3 μg/mL of mercury respectively, indicating a gradual increase in apoptotic cells with increasing doses of mercury. The percentages of Caspase 3 positive cells undergoing late apoptosis were 3.58 ± 0.03%, 17.06 ± 0.05%, 23.32 ± 0.03%, and 34.51 ± 0.01% for 0, 1, 2, and 3 μg/mL of mercury respectively, also indicating a gradual increase in Caspase positive cells with increasing doses of mercury. Full article

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Open AccessArticle

Internalization of Near-Infrared Fluorescent Dyes within Isolated Leukocyte Populations

by Michael Baker, Colette Ntam, Carroll T. Reese, Tanika V. Martin, Satia Carrington, Jane Leotaub, Leonette Cox, Richard J. Williams and Dwayne A. Hill

Int. J. Environ. Res. Public Health 2006, 3(1), 31-37; https://doi.org/10.3390/ijerph2006030004 - 31 Mar 2006

Cited by 2 | Viewed by 9098

Abstract

Scientists have expressed continued interest in the development of microsensor technology that can indicate toxicity that occurs within a cell after a chemical challenge. One of the more useful approaches of microsensor technology is the application of fluorescent spectroscopy to indicate early-stage injury [...] Read more.

Scientists have expressed continued interest in the development of microsensor technology that can indicate toxicity that occurs within a cell after a chemical challenge. One of the more useful approaches of microsensor technology is the application of fluorescent spectroscopy to indicate early-stage injury with optimal specificity and decreased background interference. If the toxicity is detected during the early onset period of injury, then the probability for therapeutic recovery is promising. There has been increasing interest in the use of infrared (IR) and near infrared (NIR) dyes as biological microsensors due to their fluorescent spectral characteristics. Three of the most essential characteristics are the ability to minimize background interference by extraneous biological matrices, to exhibit optimal molar absorptivity and quantum yields, to maintain chronic cellular homeostasis. Therefore, the present study was developed to determine if selected NIR dyes would distribute within isolated neutrophil populations without altering normal cellular homeostasis using fluorescent wavelength analysis. The results demonstrate that selected NIR dyes undergo internalization within target cell populations while maintaining cell viability and homeostasis. In addition, these dyes demonstrate changes in absorbance and fluorescence analysis after the immune cells were challenged with a stimulant. Moreover, critical cellular functions, such as degranulation and superoxide production were not compromised by the internalization of the NIR dyes. These data suggest that selected NIR dyes can undergo intracellular uptake within neutrophil cultures without altering the normal functional capabilities of the targeted cell population. Full article

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Open AccessArticle

Exposure to Chlorinated Biphenyls Causes Polymorphonucleocytes to Induce Progenitor Cell Toxicity in Culture

by Dwayne A. Hill, Carroll T. Reese, Dwane Clarke and Tanika V. Martin

Int. J. Environ. Res. Public Health 2006, 3(1), 23-30; https://doi.org/10.3390/ijerph2006030003 - 31 Mar 2006

Cited by 1 | Viewed by 8420

Abstract

Progenitor cells (PC) are the precursors for many developmental structures and are sensitive to a variety of toxic agents including the environmental contaminants, polychlorinated biphenyls (PCBs). The mechanism(s) that contributes to the development of PCB-induced progenitor cell-related fetotoxicities are not completely understood. However, [...] Read more.

Progenitor cells (PC) are the precursors for many developmental structures and are sensitive to a variety of toxic agents including the environmental contaminants, polychlorinated biphenyls (PCBs). The mechanism(s) that contributes to the development of PCB-induced progenitor cell-related fetotoxicities are not completely understood. However, several studies have demonstrated an important role for neutrophils (polymorphonucleocytes) in the development of PCB induced toxicities. Our recent findings have indicated that conditioned medium collected from PC (CMPC) exposed to a single dose of the PCB mixture, Aroclor 1248, can activate isolated neutrophil populations. Because of our recent findings, this study was conducted to determine if conditioned medium from PC treated with a PCB mixture causes neutrophils to injure PC in culture. Isolated PC were cultured and treated with different concentrations of Aroclor 1248 for 24 hours. The resulting PC-derived conditioned media was collected and its affect on neutrophil activity was analyzed. Conditioned medium from PC treated with Aroclor 1248 was chemotactic for neutrophils. The conditioned medium from Aroclor 1248 treated-PC also stimulated neutrophils to release super oxide anion, cathepsin G and elastase into culture medium. Furthermore, the conditioned medium from Aroclor 1248 treated- PC was able to stimulate neutrophils to cause progenitor cell toxicity in co-cultures. The conditioned medium from Aroclor 1248 treated-PC was not toxic to individual neutrophil cultures or PC cultures. Moreover, the addition of a protease inhibitor to the co-cultures containing neutrophils and PC, afforded protection against neutrophil-induced cytotoxicity of PC. These data suggest that a PCB mixture can cause progenitor cells to produce a factor(s) that activates neutrophils and stimulates them to damage PC populations in culture. Full article

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Open AccessArticle

Neuregulin 1-Βeta Cytoprotective Role in AML 12 Mouse Hepatocytes Exposed to Pentachlorophenol

by Waneene C. Dorsey, Paul B. Tchounwou and Byron D. Ford

Int. J. Environ. Res. Public Health 2006, 3(1), 11-22; https://doi.org/10.3390/ijerph2006030002 - 31 Mar 2006

Cited by 17 | Viewed by 11174

Abstract

Neuregulins are a family of growth factor domain proteins that are structurally related to the epidermal growth factor. Accumulating evidence has shown that neuregulins have cyto- and neuroprotective properties in various cell types. In particular, the neuregulin-1 βeta (NRG1-β) isoform is well documented [...] Read more.

Neuregulins are a family of growth factor domain proteins that are structurally related to the epidermal growth factor. Accumulating evidence has shown that neuregulins have cyto- and neuroprotective properties in various cell types. In particular, the neuregulin-1 βeta (NRG1-β) isoform is well documented for its antiinflammatory properties in rat brain after acute stroke episodes. Pentachlorophenol (PCP) is an organochlorine compound that has been widely used as a biocide in several industrial, agricultural, and domestic applications. Previous investigations from our laboratory have demonstrated that PCP exerts both cytotoxic and mitogenic effects in human liver carcinoma (HepG₂) cells, primary catfish hepatocytes and AML 12 mouse hepatocytes. We have also shown that in HepG2 cells, PCP has the ability to induce stress genes that may play a role in the molecular events leading to toxicity and tumorigenesis. In the present study, we hypothesize that NRG1-β will exert its cytoprotective effects in PCP-treated AML 12 mouse hepatocytes by its ability to suppress the toxic effects of PCP. To test this hypothesis, we performed the MTT-cell respiration assay to assess cell viability, and Western-blot analysis to assess stress-related proteins as a consequence of PCP exposure. Data obtained from 48 h-viability studies demonstrated a biphasic response; showing a dose-dependent increase in cell viability within the range of 0 to 3.87 μg/mL, and a gradual decrease within the concentration range of 7.75 to 31.0 μg/mL in concomitant treatments of NRG1-β+PCP and PCP. Cell viability percentages indicated that NRG1-β+PCPtreated cells were not significantly impaired, while PCP-treated cells were appreciably affected; suggesting that NRG1-β has the ability to suppress the toxic effects of PCP. Western Blot analysis demonstrated the potential of PCP to induce oxidative stress and inflammatory response (c-fos), growth arrest and DNA damage (GADD153), proteotoxic effects (HSP70), cell cycle arrest as consequence of DNA damage (p53), mitogenic response (cyclin-D1), and apoptosis (caspase-3). NRG1-β exposure attenuated stress-related protein expression in PCP-treated AML 12 mouse hepatocytes. Here we provide clear evidence that NRG1-β exerts cytoprotective effects in AML 12 mouse hepatocytes exposed to PCP. Full article

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Open AccessArticle

Comparative Study of Domoic Acid and Okadaic Acid Induced - Chromosomal Abnormalities in the CACO-2 Cell Line

by Pinto-Silva Carvalho, R. Catia, Serge Moukha, William G. Matias and Edmond E. Creppy

Int. J. Environ. Res. Public Health 2006, 3(1), 4-10; https://doi.org/10.3390/ijerph2006030001 - 31 Mar 2006

Cited by 38 | Viewed by 11551

Abstract

Okadaic Acid (OA) the major diarrheic shellfish poisoning (DSP) toxin is known as a tumor promoter and seems likely implicated in the genesis of digestive cancer. Little is known regarding genotoxicity and carcinogenicity of Domoic Acid (DA), the major Amnesic Shellfish Poisoning (ASP) [...] Read more.

Okadaic Acid (OA) the major diarrheic shellfish poisoning (DSP) toxin is known as a tumor promoter and seems likely implicated in the genesis of digestive cancer. Little is known regarding genotoxicity and carcinogenicity of Domoic Acid (DA), the major Amnesic Shellfish Poisoning (ASP) toxin. Both OA and DA occur in seafood and are of human health concerns. Micronuclei (MN) arise from abnormalities in nuclear division during mitosis due to a failure of the mitotic spindle or by complex chromosomal configurations that pose problems during anaphase. In order to evaluate the ability of okadaic acid (OA) and domoic acid (DA) to induce DNA damage we performed the micronucleus assay using the Caco-2 cell line. To discriminate between a clastogenic or aneugenic effect of OA and DA, the micronucleus assay was conducted by cytokinesis-block micronucleus assay using cytochalasin B with Giemsa staining and/or acridine orange staining, in parallel to fluorescence in situ hybridization (FISH) using a concentrated human pan-centromeric chromosome paint probe. Our results showed that OA and DA significantly increased the frequency of MN in Caco-2 cells. The MN caused by OA are found in mononucleated cells and binucleated cells, whereas those caused by DA are mainly in binucleated cells. The results of FISH analysis showed that OA induced centromere-positive micronuclei and DA increased the percentage of MN without a centromeric signal. In conclusion, both OA and DA bear mutagenic potential as revealed in Caco-2 cells by induction of MN formation. Moreover, OA induced whole chromosome loss suggesting a specific aneugenic potential, whereas DA seems simply clastogenic. At present, one cannot rule out possible DNA damage of intestinal cells if concentrations studied are reached in vivo, since this may happen with concentrations of toxins just below regulatory limits in case of frequent consumption of contaminated shell fishes. Full article

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Open AccessEditorial

Second International Symposium on Recent Advances in Environmental Health Research

by Abdul K. Mohamed and Paul B. Tchounwou

Int. J. Environ. Res. Public Health 2006, 3(1), 1-3; https://doi.org/10.3390/ijerph2006030000 - 20 Jan 2006

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Int. J. Environ. Res. Public Health, Volume 3, Issue 1 (March 2006) – 15 articles , Pages 1-120

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