Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Toxin combo common in fish appears capable of impairing motor skills

02.03.2004


Pups of female rats exposed to a combination of polychlorinated biphenyls (PCBs) and methylmercury (MeHg) slip and fall more often trying to maneuver on a rotating rod than do pups from non-exposed moms, scientists say.



The findings, published in the February issue of the journal Toxicological Sciences, come from a study focusing on the effects of combined exposure of the two commonly found environmental contaminants on motor function driven by the cerebellum.

"Because people are exposed to these toxicants by eating fish taken from ecosystems where these chemicals accumulate, our findings suggest that we should seriously consider the possible impact of their additive toxic effects on human health," said Susan L. Schantz, a professor of veterinary biosciences at the University of Illinois at Urbana-Champaign.


Previous laboratory studies had suggested that the two chemicals act together to impair nervous system function. A study in February’s issue of the Journal of Pediatrics found that exposure to methylmercury causes heart damage and impairs brain growth.

The new study -- pursued as part of the doctoral dissertation by Schantz’s graduate student Cindy S. Roegge -- shows that motor skills were not significantly affected by methylmercury exposure alone, but when paired with PCBs the combined effect during development dramatically impacted the pups’ skills in one of three motor tests.

The research was done for the federally funded FRIENDS Children’s Environmental Health Center, a five-institution consortium based at the College of Veterinary Medicine at Illinois. Schantz is director of FRIENDS (Fox River Environment and Diet Study), which is studying the effects of exposure to toxicants in fish being eaten in large quantities by Laotian and Hmong refugees in Green Bay and Appleton, Wis.

In the study, female rats were exposed to just PCBs or just MeHg or to both chemicals, beginning four weeks before breeding and ending when their pups were weaned. None of the female rats showed signs of toxicity, said Schantz, who also is a professor in the Neuroscience Program and psychology department at Illinois.

At birth, the pups of mothers exposed to methylmercury alone did not differ in weight from the control group. The birth weight of pups whose mothers had been exposed to just PCBs or both chemicals was slightly, but significantly, less than the control animals.

At weaning, the weight of pups exposed to PCBs was as much as 11 percent below that of control animals, while the pups in the PCB-MeHg exposure group weighed as much as 15 percent less than controls.

Two months later, one male and female pup from each litter were tested for the next four weeks on their abilities to navigate vertical ropes, parallel bars and various speeds of rotating rods. At the end, female pups whose mothers had been exposed to MeHg were slightly impaired on the rope-climbing test, while their male counterparts actually had less hind-limb slips on the parallel bars. Overall, the results of the MeHg-exposed pups were not significantly different than that of the control animals.

However, on the rotating rods the impact of exposure to both PCBs and methylmercury became clear. As the speed of the rods exceeded 25 rpm, the pups, regardless of sex, that were exposed to both toxicants during their mothers’ pregnancies slipped significantly more often than their control counterparts. Exposure to either of the chemicals alone did not significantly impact performance.

However, Schantz said, the tests showed that PCB exposure contributed more than did the methylmercury to the pups’ deficits, although the low dosage of MeHg used in the study (1.20 milligrams compared with the 2 to 18 mg used in previous studies of motor skills) may explain why.

It could be, the researchers wrote, that the chemicals have independent mechanisms of toxicity or they each act by means of the same mechanism but with greater impact together.

In addition to Schantz and Roegge, the other contributors were Illinois doctoral students Victor C. Wang and Brian E. Powers; Sherilyn Villareal, a visiting research specialist in veterinary biosciences; William T. Greenough, a professor of psychology and cell and structural biology at the Beckman Institute for Advanced Science and Technology at Illinois; and Anna Y. Klintsova, a psychology professor at Binghamton University in New York who formerly worked with Greenough at the Beckman Institute.


The U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences funded the study. The two agencies also fund the FRIENDS Children’s Environmental Health Center.

Jim Barlow | UIUC
Further information:
http://www.news.uiuc.edu/news/04/0301fishtoxin.html

More articles from Studies and Analyses:

nachricht Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>