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| TITLE: | Human B-cell Biology in Electric and Magnetic Environments | ||
| Principal Investigator |
Shashikant Mehta, Ph.D. | Roger Williams Medical Center/Brown University | |
| Health Relevance |
Other: Immunological Effects | ||
| Research Categories |
Cellular Function | Cell Proliferation | Immune Response |
| FY95 Funds | R29ES05970 $ 103,425 | Start Date 09/30/92 | End Date 09/29/97 |
| Rationale and Summary |
The long-term objectives of this study are to investigate how EMF exposures typical of home and work environments could promote the incidence of B-cell related cancers, and to determine the role of cell surface receptors in the growth and development of normal and abnormal lymphocytes under the influence of 60 Hz fields. In particular, we want to demonstrate 1) whether EMF exposure causes changes in the development and growth of lymphocytes, 2) whether such exposure causes changes in the secretion of regulatory proteins, 3) under what field conditions (amplitude, presence or absence of DC field) changes occur, and 4) whether observed effects are due to the electric field induced by the 60 Hz magnetic field or directly due to the alternating magnetic field. Thus far we have shown that human lymphocyte cultures stimulated by a plant derived product, exhibit a 1.4 to 1.7 fold increase in proliferation when exposed to magnetic fields for 3 days, compared to unexposed cells from the same donor. We have also shown that secretion of at least one regulatory protein (IL-2) is affected by a 1 Gauss (1.21 G peak), 60 Hz field under conditions when the induced electric field varies over a 5.5 to 1 range in amplitude, suggesting that the effect is directly due to the magnetic field. In all of our experiments we have noted that lymphocytes and the secretions by lymphocytes are affected by the magnetic field only in the presence of cell activators (the plant product PHA for T-cells, specific antibodies for B-cells). | ||
| Experimental Design and Exposure Conditions |
Cell Lines: B-cells and T-cells derived from normal human donors, two leukemic B-cell lines and
a T-cell line of human origin.
Cell Processing: Normal human blood is processed on a density gradient to separate B and T cells.
Leukemic cell lines are routinely maintained in growth phase in culture medium.
End Analysis: Cell growth is assessed by 3H-thymidine. Protein secretions are measured by
either bioassay or commercially available ELISA kits. Magnetic field exposed and unexposed
"control" cells are always obtained from the same donors or (in the case of cell lines) from the
same cell pool. All experiments are performed using multiple culture vessels and subjected to
statistical analysis.
Exposure Parameters: Experiments performed during the first two years employed nested Helmholtz coils to control the DC and AC field environment. AC exposure was done with the environmental static magnetic field cancelled to near zero. Control cultures were located in a different incubator (under temperature, CO2 and moisture conditions identical with those in the exposure incubator) where the static field was approximately 0.38 gauss. Starting in the summer of 1995 we are using a new system in which a central incubator supplies heated, moist CO2 containing air to two identical "satellites" made of non-magnetic material. Both satellites are surrounded by bi-filar wound "Merritt" (for AC) and Helmholtz coils (for DC). |
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| Quality Assurance Measures |
The use of identical bi-filar wound coils around both "satellites" allows complete blind performance of experiments since the biologists do not know until after final data analysis has been completed which samples were exposed to the magnetic field (field parameters are set by the engineering personnel and randomly changed among satellite incubators). Field amplitudes, including stray fields, are initially set using fluxgate magnetometers and continuously recorded using current and voltage measurements. In the new system both AC exposed and control cells have been kept at near zero level static magnetic fields. Most experiments that were performed during the first two years using different incubators for exposed and control cells are being repeated using the new system. | ||
| Results and Discussion |
Our findings to date include increased IL-2 production by normal human T-cells (at 1 gauss peak). This increase did not lead to increased T-cell growth. The significance of this finding is that increased IL-2 production may affect other immune cells, such as B-cells, in vivo. IL-2 production appears to be affected directly by the 60 Hz magnetic field at the 1 gauss peak level rather than by the induced electric field. This suggests that magnetic fields rather than low level electric fields appear to affect this type of immune cell response. Finally, IL-1 production by monocytes is decreased significantly by exposure (0.5 and 1 gauss peak). Similar effects have been observed in vivo by other investigators. This finding is important because IL-1 stimulates many other cells contributing to immune and inflammatory responses. | ||
| Recent Publications |
1. Lefevre M., Blackinton D., Cherlin D., Mehta S. and C. Polk: Modulation of human immune
cell function in low frequency magnetic field. Proc. Institute of Electric and Electronic Engineers
/ Eng. in Medicine and Biology. 59, 1992.
2. Mehta S., Blackinton D, Lefebvre M., Wiesendanger M., Cherlin D., Wanebo H. and C. Polk: Accelerated lymphocyte growth in 15 Hz, 1 G magnetic field. "Electricity and Magnetism in Biology and Medicine" (M. Blank, ed) SanFrancisco Press, pp 637-640, 1993. 3. Salvatore J., Blackinton D., Polk C. and Mehta S.: Non-ionizing Electromagnetic Radiation: A Study of Carcinogenic and Cancer Treatment Potential. Rev. on Environmental Health, 10, 197- 207, 1994. 4. Mehta, S., Berg M., Cherlin D. and Polk C.: Effect of 60 Hz, 0.86 Gauss Magnetic Field on IL- 2 Production by Human T-cells is Independent of the Amplitude Range of the Induced Electric Field over a 5.5/1 Amplitude Range. (A-7) in The Annual Review of Research on Biological Effects of Electric and Magnetic Fields from the Generation, Delivery and Use of Electricity, Albuquerque, New Mexico, 1994. 5. Mehta, S., Berg M., Deeds S., Cherlin D., Blackinton D. and Polk C.: Modulation of Human Adult and Umbilical Cord Natural Killer Cell Function after Exposure to a 60 Hz. 0.86 G Magnetic Field. (P-70) in The Annual Review of Research on Biological Effects of Electric and Magnetic Fields from the Generation, Delivery and Use of Electricity, Albuquerque, New Mexico, 1994. |
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