157
Static, Low-Frequency, and Pulsed Magnetic Fields
enteritidis, Serratia marcescens, and Staphylococcus aureus; they were tested under SMF
exposure for up to 24 hours in either a homogeneous SMF of 159 mT or three types
of inhomogeneous SMFs: (1) peak-to-peak magnetic flux density 477 mT with a lateral
magnetic gradient of 47.7 T/m, (2) 12 mT with 1.2 T/m, or (3) 2.8 mT with 0.3 T/m. Even
the longest period of exposure failed to produce any effect in the growth of bacteria.
Cellini et al. (2008) investigated the influence of an ELF-EMF (50 Hz; 0.1, 0.5, and
1.0 mT; for 20–120 minutes) on the viability of E. coli ATCC 700926. Exposed samples
and controls displayed similar total and culturable counts, whereas increased cell viability was observed in exposed samples reincubated for 24 hours outside the solenoid
compared with the corresponding controls. An EMF exposure produced significant
change in E. coli morphotype with a presence of coccoid cells aggregated in clusters after
24 hours of reincubation outside the solenoid. Atypical lengthened bacterial forms were
also observed suggesting a probable alteration during cell division. No changes among
DNA fingerprintings and some differences in RNA-AFLP (amplified fragment length
polymorphism) analysis were observed for each EMF intensity evaluated. These results
indicated that EMF exposure acts as a stressing factor on bacteria, which represents a
suitable model to investigate acute and chronic effects related to ELF-EMF exposure.
3.5 Medical Applications
Ueno, Sekino, and Ogiue-Ikeda (2006) and Yamaguchi-Sekino, Sekino, and Ueno (2011)
reviewed recent advances in biomagnetics and bioimaging techniques such as TMS,
MEG, MRI, and magnetic orientation for tissue engineering. In addition to this review,
more recent findings related to medical applications are introduced in Sections 3.5.1
through 3.5.5.
3.5.1 Transcranial Magnetic Stimulation and Induced Current
Transcranial magnetic stimulation, for example, single- and paired-pulse TMSs and
rTMS, is a useful method to examine dynamic brain function without causing any pain,
producing a so-called virtual lesion or virtual excitation for a short period. Accordingly,
TMS has become increasingly popular and is now a well-established and noninvasive technique in cognitive neuroscience, in particular, in functional, diagnostic, and
therapeutic research on the brain. In brain functional research, magnetic stimulation
for the temporary blockage or modification of the facultative information process and
cognitive process of various sensory systems has been used to identify localization and
connecting pathways of brain function. Single- or paired-pulse TMS and rTMS were
reviewed by Pascual-Leone et al. (2002) and Fitzgerald, Fountain, and Daskalakis
(2006), respectively.
In some cases, applications of TMS disturb brain function temporarily, which results
in a virtual lesion in the brain. Zangaladze et al. (1999) showed that the disruption of the
function of the occipital cortex with the use of focal TMS interferes with the tactile discrimination of grating orientation. Epstein et al. (2002) used TMS to investigate memory
encoding and retrieval, particularly the role of DLPFC in associative memory for visual
patterns. TMS was applied on dorsolateral prefrontal cortex of human subjects during
Static, Low-Frequency, and Pulsed Magnetic Fields
enteritidis, Serratia marcescens, and Staphylococcus aureus; they were tested under SMF
exposure for up to 24 hours in either a homogeneous SMF of 159 mT or three types
of inhomogeneous SMFs: (1) peak-to-peak magnetic flux density 477 mT with a lateral
magnetic gradient of 47.7 T/m, (2) 12 mT with 1.2 T/m, or (3) 2.8 mT with 0.3 T/m. Even
the longest period of exposure failed to produce any effect in the growth of bacteria.
Cellini et al. (2008) investigated the influence of an ELF-EMF (50 Hz; 0.1, 0.5, and
1.0 mT; for 20–120 minutes) on the viability of E. coli ATCC 700926. Exposed samples
and controls displayed similar total and culturable counts, whereas increased cell viability was observed in exposed samples reincubated for 24 hours outside the solenoid
compared with the corresponding controls. An EMF exposure produced significant
change in E. coli morphotype with a presence of coccoid cells aggregated in clusters after
24 hours of reincubation outside the solenoid. Atypical lengthened bacterial forms were
also observed suggesting a probable alteration during cell division. No changes among
DNA fingerprintings and some differences in RNA-AFLP (amplified fragment length
polymorphism) analysis were observed for each EMF intensity evaluated. These results
indicated that EMF exposure acts as a stressing factor on bacteria, which represents a
suitable model to investigate acute and chronic effects related to ELF-EMF exposure.
3.5 Medical Applications
Ueno, Sekino, and Ogiue-Ikeda (2006) and Yamaguchi-Sekino, Sekino, and Ueno (2011)
reviewed recent advances in biomagnetics and bioimaging techniques such as TMS,
MEG, MRI, and magnetic orientation for tissue engineering. In addition to this review,
more recent findings related to medical applications are introduced in Sections 3.5.1
through 3.5.5.
3.5.1 Transcranial Magnetic Stimulation and Induced Current
Transcranial magnetic stimulation, for example, single- and paired-pulse TMSs and
rTMS, is a useful method to examine dynamic brain function without causing any pain,
producing a so-called virtual lesion or virtual excitation for a short period. Accordingly,
TMS has become increasingly popular and is now a well-established and noninvasive technique in cognitive neuroscience, in particular, in functional, diagnostic, and
therapeutic research on the brain. In brain functional research, magnetic stimulation
for the temporary blockage or modification of the facultative information process and
cognitive process of various sensory systems has been used to identify localization and
connecting pathways of brain function. Single- or paired-pulse TMS and rTMS were
reviewed by Pascual-Leone et al. (2002) and Fitzgerald, Fountain, and Daskalakis
(2006), respectively.
In some cases, applications of TMS disturb brain function temporarily, which results
in a virtual lesion in the brain. Zangaladze et al. (1999) showed that the disruption of the
function of the occipital cortex with the use of focal TMS interferes with the tactile discrimination of grating orientation. Epstein et al. (2002) used TMS to investigate memory
encoding and retrieval, particularly the role of DLPFC in associative memory for visual
patterns. TMS was applied on dorsolateral prefrontal cortex of human subjects during