Table 2 Characteristics of individual vertebrate studies

Altmann [62]

(article in German)

guinea pig (n = 5 per group, crossover design)

static EF of 0.42 kV/m and control only under Faraday conditions

organ parameters:

oxygen consumption

metabolism was increased upon static EF exposure compared to a shielded environment in a Faraday cage

also studied AC EF; not clear if peer-reviewed

Altmann [49]

(article in German)

white mouse, budgerigar and zebra finch, guinea pig (n = ?)

static EF of 1 kV/m (mouse, budgie, zebra finch (exposure duration regarding activity assessment was 1 h)), 0.42 kV/m (guinea pig); control only under Faraday conditions

perception/behavior:

activity (mouse, budgie, zebra finch),

organ parameters:

free amino acids in liver or muscle tissue (guinea pig, mouse)

increased activity accompanied by higher oxygen consumption in guinea pig and higher level of free amino acids in all examined animals compared to a shielded environment in a Faraday cage

not clear if peer-reviewed

Angell et al. [44]

cattle (n = 200 in total; 2 herds of 50 animals under the HVDC line and 2 herds of 50 animals as controls)

static EF of 5.6 kV/m (mean value) and static MF (mean value of 4.1 nA/m²) and air ions (mean value of 13 k ions/cm³) from a 500 kV HVDC line continuously for 30 months

reproduction/development:

productivity and general health status of cows and calves

no significant effect

experimental field study; same animals as in Ganskopp et al. [45]

Arzruny et al. [74]

rats (n = 20 per group, 2 groups)

static EF of 200 kV/m for 1 h

hematology/immunology:

enzyme activity of type A phospholipases, lysophospholipase in erythrocyte and mitochondrial membranes

increase of enzyme activities in erythrocytes

Atalay [59]

40 male guinea pigs (10 vertical, 10 horizontal, 20 control)

static EF of 1.9 kV/m (horizontal and vertical) for 9 h/day for 3 days

organ parameters:

collagen synthesis (hydroxyproline levels in lungs)

increased hydroxyproline levels; vertical EF more effective than horizontal

Atalay and Güler [63]

40 male guinea pigs (10 vertical, 10 horizontal, 20 control)

static EF of 0.58 kV/m (horizontal and vertical) for 9 h/day for 3 days

organ parameters:

collagen synthesis (hydroxyproline level in liver)

decrease in hydroxyproline level; vertical EF more effective than horizontal

Bailey and Charry [39]

male Sprague–Dawley rats (n = 5–20 per examined endpoint)

negative and positive static EF (3 kV/m, 12 kV/m) partially with air ions (5 × 10³/cm³, 5 × 10⁵/cm³) for 2, 18, or 66 h

perception/behavior:

locomotor activity, rearing behavior, food and water consumption

no significant effect

main focus was on air ions

Bailey and Charry [38]

male Sprague–Dawley rats (n = 6–16 per experiment)

negative and positive static EF of 3 kV/m without or with air ions (5*10⁵/cm³) of the respective polarity; exposure duration 2, 18 or 66 h

brain/nervous system:

serotonin level in the rat’s brain

no significant effect

main focus was on air ions

Charry and Bailey [40]

male Sprague–Dawley rats (n = 5–15 per experiment)

negative and positive static EF of 3 kV/m without or with air ions (2*10⁵/cm³) of the respective polarity; exposure duration 2, 18 or 66 h

brain/nervous system:

norepinephrine and dopamine levels in the rat’s brain

no significant effect

main focus was on air ions

Cieslar et al. [70]

128 male Wistar albino rats (4 groups, 32 animals, respectively: 3 different EF strengths and a control group; 8 animals per time point: after 14, 28, 56 d of exposure or 28 d after a 56 d exposure)

static EF of 16, 25, or 35 kV/m for 8 h/day for 14, 28, or 56 days

organ parameters and hematology/immunology:

oxidative stress (enzyme activity of catalase, superoxide dismutase, and level of gluthation peroxide, lipid peroxidation) in blood and liver

transient changes in prooxidant-antioxidant balance

Creim et al. [47]

male Long Evans rats; 380 rats in total, in 9 different experiments (n = 40, except for one experiment with n = 20)

negative and positive static EF (−55 to 80 kV/m) with air ions (1.4*10⁶) or -/+ 55 kV/m with different air ion concentrations (2*10³ to 2.5*10⁵) for 1 h

perception/behavior:

spatial avoidance behavior

rats significantly avoided the exposed area (≥55 kV/m) regardless of air ions

Creim et al. [46]

male Long Evans rats; 56 rats in total, divided into 4 groups (n = 14 per group)

negative and positive static EF of 75 kV/m with air ions (2*10⁵) for 4 h/day for 5 days

perception/behavior:

taste aversion learning

no significant effect

Fam [50]

male and female ICR-SW mice (for exposure: 2 groups, male and female n = 21, respectively and for control n = 24/24 male/female; additionally progenies of these 4 groups were exposed and examined)

static EF of 340 kV/m for 18–22 h/day, parents approx. 5000 h (approx. 30 weeks) in total and their progenies 2000 h in total

perception/behavior:

water consumption hematology/immunology:

blood parameters

reproduction/development:

growth; fertility; number and weight of pups

organ parameters:

histomorphology of different organs

partially less water consumption;

some changes in blood parameters (e.g., lower level of ß-globulins in males and higher in females, lower level of hemoglobin and reduced number of lymphocytes in females); weight of pups higher in first and fourth week after birth; no effect on number of pups; no effect on organ histomorphology

Ganskopp et al. [45]

see Angell et al. 1990 [44]

static EF of −3.3–24.7 kV/m under the positive conductor and −35.6–6.9 kV/m under the negative conductor

perception/behavior:

activity (nursing, drinking, walking, lying, standing); distribution in panel

more time was spent for nursing and drinking; fewer exposed than control cattle were observed in the central areas of pens but still most of the animals in the central area

experimental field study; same animals as in Angell et al. [44]

Gray et al. [37]

female B6C3F1 mice implanted with murine mammary adenocarcinoma (n = 44, 11 mice per group)

static EF of 450 kV/m; mice in restraining tubes while exposed for 4 h/day for 13 days; all mice received the chemotherapeutic agent adriamycin

therapeutic approach:

tumor development

greater tumor regression

also static MF and switching EF

Güler and Atalay [64]

guinea pig (n = 40 in total; 3 groups: n = 10 vertical static EF, n = 10 horizontal static EF, n = 20 control group)

static EF of 1.9 kV/m for 9 h/day for 3 days (horizontal and vertical)

organ parameters:

hydroxyproline levels of liver, lungs and kidney

increased hydroxyproline levels in liver, lungs and kidney; vertical EF more effective than horizontal

for liver, exactly the same values as in [65], possibly published twice

Güler et al. [65]

male guinea pig (n = 60, divided into 6 groups)

static EF of 0.9 to 1.9 kV/m for 9 h/day for 3 days (vertical and horizontal)

organ parameters:

collagen synthesis (hydroxyproline level in the liver; histomorphological examination of liver slices)

0.9 kV/m vertical and horizontal EF decreased the amount of hydroxyproline in the liver, while the 1.9 kV/m vertical and horizontal EF increased the amount of hydroxyproline

for 1.9 kV/m exactly the same values as in [64] for liver, possibly published twice

Güler et al. [66]

male guinea pigs (n = 70 in total, 6 experimental groups and 1 control group with n = 10 each)

static EF of 0.3, 0.9, and 1.8 kV/m for 8 h/day for 3 days (vertical and horizontal)

organ parameters:

lipid peroxidation, superoxide dismutase activity in spleen and testis

0.9 and 1.8 kV/m increased the lipid peroxidation and superoxide dismutase activity

Güler et al. [67]

male guinea pigs (280 animals in total, 14 groups with n = 20 each)

static EF of 0.3, 0.6, 0.8, 0.9, 1, 1.35, 1.5, 1.8, and 1.9 kV/m for 8 h/day for 3 days (vertical)

organ parameters:

oxidative stress in spleen and testes

oxidative stress increased with increasing static EF strength

also studied AC EF; main focus was on developing a theoretic neural network

Güler et al. [71]

male guinea pig (n = 140, divided into 14 groups, additional 20 animals for control group)

static EF of 0.3, 0.6, 0.8, 1, 1.35, 1.5, and 1.8 kV/m for 8 h/day for 3 days (vertical and horizontal)

organ parameters and hematology/immunology:

oxidative stress: lipid peroxidation and enzyme activity of superoxide dismutase in guinea pigs’ plasma, liver, lungs and kidney

liver, kidney: significant increase of lipid peroxidation and SOD activity 1–1.8 kV/m; plasma: significant increase of lipid peroxidation and SOD activity 0.8–1.8 kV/m; lungs: significant increase of lipid peroxidation and SOD activity 1.35–1.8 kV/m; no difference between horizontal and vertical application of EF

also studied AC EF

Harutyunyan and Artsruni [75]

female albino rats (n = 72, divided into 3 groups)

static EF of 200 kV/m for 1 h or 6 h/day for 6 days

hematology/immunology:

proteome changes in blood plasma

increased lysozyme activity after 1 h and 6 h/day for 6 days; decrease of globular proteins coinciding with clotting acceleration after 1 h; attenuation of clotting-dependent proteome modifications reflected with incomplete coagulation after 6 h/day for 6 days

Harutyunyan and Sahakyan [76]

male albino rats (n = 10 per group, 2 experimental groups and 2 control groups)

static EF of 200 kV/m for 1 h or 6 h/day for 6 days

hematology/immunology:

oxidative processes in red blood cells and cell number

after 1 h exposure: reduced number of red blood cells, increased oxidative stress and increased enzyme activities; after 6 days: increased number of red blood cells, oxidative stress parameters decreased or increased

Kato et al. [48]

hindleg of anesthetized cats (n = 13)

static EF of 180–310 kV/m (both polarities) for 0.05, 0.2, 1.1, or 2 s for hair movement and for 1.5–3 min for action potential recording (sural nerve in 10 cats and sural, gastrocnemius, and articular nerves in 3 cats)

perception/behavior:

hair movement; action potentials from afferent nerve fibers

cat hairs were attracted to the upper electrode when exposed to static EF of 180 kV/m or more; afferent impulses were evoked from hair receptors that were probably stimulated by the hair movement; deeper receptors were not affected by the EF

Kellogg and Yost [41]

female NAMRU mice (n = 200 in total, 8 groups, n = 25 each, in results partially less animals stated)

static EF of 1.8 kV/m plus 2*10³ air ions/cm³; static EF of 2.4 kV/m plus 2*10⁵air ions/cm³; static EF of 2 kV/m (both polarities, respectively); 2 control groups; exposure started with approx. 6 weeks until end of life (except for 6 h every 2 weeks when cages were cleaned)

hematology/immunology:

mortality

no effect found between static EF alone versus control group

main focus was on air ions; extension of [42, 43]; but unclear why different field strengths are reported. Duplicative publication of results from Kellogg et al (1985a, b) [42, 43]. In second year proteus vulgaris infection in all exposure groups caused severe gastroenteritis, splenic hypertrophy, occasional purulent salpingitis, and death.

Kellogg et al. [42]

female NAMRU mice (n = 200 in total, 8 groups, n = 25 each, in results partially less animals stated)

static EF of 1.75 kV/m plus 2*10³ air ions/cm³; static EF of 1.98 kV/m plus 2*10⁵ air ions/cm³; static EF of 2 kV/m (both polarities, respectively); 2 control groups; exposure started with approx. 6 weeks until end of life (in this article only first year reported)

hematology/immunology:

blood parameters (serotonin, glucose, cholesterol, urea nitrogen, globulin) every three months

increased mean glucose level in positive EF and decreased urea nitrogen in negative EF compared to overall mean values

main focus was on air ions; results for first year of a two year study, see [43] for second year; possibly mild vitamin deficiency

Kellogg et al. [43]

see Kellogg et al. [42]

see Kellogg et al. [42] (in this article only second year reported)

hematology/immunology:

blood parameters (serotonin, glucose, cholesterol, urea nitrogen, globulin); survival rate

organ parameters:

organ parameters (weight, histologic changes)

animals in static EF lived longer (no significance given) and increased mean glucose level in positive EF compared to overall mean value; no effect on organ weights

main focus was on air ions; results for second year of a two year study, see [42] for first year; possibly mild vitamin deficiency. In second year, proteus vulgaris infection in all exposure groups caused severe gastroenteritis, splenic hypertrophy, occasional purulent salpingitis, and death.

Krueger et al. [73]

NAMRU mice (n = 90–220 mice per group, 12 groups)

static EF of ca. 0.1 kV/m (ion depleted air or with 2.7-5*10³ air ions) or static EF of 4–6 kV/m (ion depleted air or with 2.3-5*10⁵ air ions) for up to 11 days

hematology/immunology:

mortality after influenza infection

no significant effect

main focus was on air ions

Lott and McCain [58]

male Sprague–Dawley rats (in total, n = 60)

surface electrodes measured EEG (n = 30) electrodes implanted in the brain measured hypothalamic activity (n = 30); 15 rats of each group were exposed to a pulsed EF and 15 to a static EF of 10 kV/m for 50 min during EEG recording; experiments were performed under anesthesia

brain/nervous system:

brain activity and hypothalamic activity

increased brain activity measured with surface electrodes and decreased hypothalamic activity (implanted electrodes); when EF was turned off, brain activity returned back to baseline before exposure

Marino et al. [78]

female Swiss Ha/ICR mice (n = 5 per EF strength and exposure duration)

2.7 kV/m and 10.7 kV/m (parallel to earth’s surface); 5.7 kV/m (perpendicular to the earth’s surface) for 7, 14, or 21 days

hematology/immunology:

concentration of serum proteins (albumin, alpha-, beta-, gamma-protein)

beta globulin increased under parallel and decreased under perpendicular exposure; albumin vice versa; gamma globulin increased under perpendicular exposure

Marino et al. [69]

male Sprague–Dawley rats (7 different exposure groups with n = 12–20, corresponding control groups with n = 8–23); female Swiss Ha/ICR mice bearing Ehrlich ascites tumor cells (n = 7 exposed, n = 6 control)

rats: static vertical EF of 0.6, 2.8, 5.6, 19.7 kV/m and horizontal static EF of 0.3, 2.8, and 9.8 kV/m for 30 days; mice: horizontal static EF of 8–16 kV/m for 14 days

hematology/immunology (rats):

body weight, serum protein concentration

organ parameters (rats):

histomorphology of different organs (lungs, liver, kidney), general examination

genotoxicity (mice):

chromosomal aberrations in tumor cells

rats: secondary glaucoma (only vertical EF); altered serum protein concentration; no effects on organ histomorphology; mice: production of chromosomal abnormalities in tumor cells

Mayyasi and Terry [51]

King-Holtzman rats (in total, n = 240, different age and sex groups; additional groups to test the influence of noise)

static EF of 1.6 and 16 kV/m for 5 h

perception/behavior:

behavior, learning

improved learning (less errors) and better swimming performance

Mitchell et al. [79]

female mice (Swiss Ha/ICR) (n = 8–12 per group, data taken from results, number not stated in methods)

static EF in the range of 8 to 16 kV/m up to 15 weeks (horizontal and vertical)

genotoxicity:

chromosomal aberrations in tumor cells

increase in the percentage of abnormal chromosomes after 2 weeks of horizontal exposure; disappearance of the aberrant chromosomes after extended exposure

extension study of Marino et al. [69]

Möse and Fischer [52] (article in German)

white mice (n = 5 for locomotor activity and food/water consumption), n = 10 for rectal temperature, n = 12 for litter frequency, no number given for oxygen consumption of liver)

static EF of 23.8 kV/m for 15 days up to approx. 4 months (litter frequency) (mostly 15 to 20 days)

perception/behavior:

locomotor activity, food/water consumption, rectal temperature

reproduction/development:

litter frequency

organ parameters:

oxygen consumption of liver pieces

significant increase of locomotor activity, food and water consumption and rectal temperature; initially normal number of offspring, over the later period complete absence of offspring; no effect on oxygen consumption of liver pieces

not clear if peer-reviewed

Möse et al. [56]

(article in German)

rat and guinea pig (n = ?)

static EF of 23.8 kV/m for 6 days

organ parameters and brain/nervous System:

serotonin concentration in uterus of rats, brain and ileum of guinea pigs

reduced serotonin levels in brain and uterus, increased serotonin levels in ileum

not clear if peer-reviewed; contradictory statements if brain was taken from rats or guinea pigs

Möse et al. [68]

(article in German)

rat (uterus) and guinea pig (intestine) (n = ?)

static EF of 23.8 kV/m for 3–21 days

organ parameters:

ability of isolated smooth muscles (intestine and uterus) to react to stimulating drugs

smooth muscles reacted less to stimulating drugs

not clear if peer-reviewed

Möse et al. [60]

(article in German)

male NMRI mice (n = 25 per group, 3 groups: static EF, control group under ambient conditions, control group in Faraday cage)

static EF of 23.8 kV/m for 8 days

organ parameters:

oxygen consumption of isolated liver pieces

increased oxygen consumption under static EF exposure and decreased consumption under Faraday conditions in comparison to control group

not clear if peer-reviewed

Möse et al. [72] (article in German)

NMRI-Hahn mice (n = 10–15 per EF strength and condition)

static EF of 0.04, 0.2, 1, 5 and 24 kV/m for 15 days; in addition to control group under laboratory conditions also control in Faraday cage; mice were immunized with sheep erythrocytes at day 7 and 11 of exposure

hematology/immunology:

immunization level (plaque formation on spleens, spleen weight, number of spleen cells, haemagglutination titers)

immunization level increased under static EF exposure compared to a shielded environment in a Faraday cage

not clear if peer-reviewed

Okudan et al. [61]

male and female Wistar rats (progenies of 3 dams, already exposed during pregnancy); (n = 10 for static EF, n = 7 for control)

static EF of 10 kV/m for 28 days (14 days in utero and 14 days postnatal)

organ parameters:

bone mineral density; bone mineral content

decrease in bone mineral content and bone mineral density

also studied AC EF

Sahakyan et al. [77]

female rats (n = 120; divided into 2 groups)

static EF of 200 kV/m for 6 h/day for 6 days

hematology/immunology:

lipid-protein interactions in rat erythrocyte membranes

redistribution of membrane surface charge, conformational alterations of membrane integral proteins, increase of the immersion degree of the peripheral proteins

incomplete reference list

Xu et al. [57]

male ICR mice (n = 90, divided into 2 experimental groups and 1 control group of 30 animals each)

static EF of 2.3–15.4 kV/m (experimental group 1) and 9.2–21.85 kV/m (experimental group 2) from a HVDC line for 35 days except for raining and low temperature days

brain/nervous System:

cognition: learning, memory; glutamate and GABA concentrations in the brain

impaired memory abilities