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 The Great Unknown: Risk-Taking Behavior in Adolescents
19.01.2017 | Max-Planck-Institut für Bildungsforschung

nachricht A sudden drop in outdoor temperature increases the risk of respiratory infections
11.01.2017 | University of Gothenburg

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: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>