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PubMed2002

In vivo and in vitro effects of a pulsed electromagnetic field on net calcium flux in rat calvarial bone.

Although PEMF's have been found to promote fracture healing and to modulate the activity of bone cells in vitro, effects on bone metabolism are largely unexplored. A bioassay using neonatal rat calvarial bone was used to determine the early effects of a pulsing electromagnetic field (PEMF) exposure in vivo and in vitro on bone metabolic calcium exchange. Bone discs taken from whole body exposed animals (0-4 hours) show a log exposure time-dependent average increase in net Ca uptake in the 0-50% range (r2 = 0.83). This increase could be detected immediately after exposure and also after 24 hours, but not 48 hours later. Animals given whole body PEMF exposure also showed a decrease in serum calcium and did not elevate serum Ca after administration of exogenous parathyroid hormone (PTH). Bone discs from untreated rats, exposed to PEMF for 15 minutes in vitro and then assayed, showed net Ca uptake increases of a similar magnitude and also were refractory to the Ca-releasing effect of PTH. Unexposed discs responded normally to PTH by decreasing net Ca uptake. Treatment of calvarial discs with calcitonin or acetazolamide, both of which inactivate osteoclasts, made the bone refractory to further increases in Ca uptake by PEMF. These results suggest that PEMF exposure produces PTH-refractory osteoclastics and has a relatively rapid effect on increasing net bone Ca uptake, putatively due to a decrease in PTH/paracrine-mediated bone resorption.

Acetazolamide↗
PubMed1996

[Usefulness of electromagnetic fields in the treatment of hip avascular necrosis: a prospective study of 30 cases].

A series is here reported of 30 hips from 21 patients with the diagnosis of avascular necrosis in different stages (Ficat 0 = 1, I = 4, II = 13, III = 10, IV = 2). Patients underwent external electro-stimulation by means of a electromagnetic field generator, and results were evaluated by NMR at three-month intervals. Lesions were categorized by NMR: < 25%, 25%-50%, and > 50% of involved head volume. The grading of lesions yielded the following distribution: grade 1 = 12, grade 2 = 10, and grade 3 = 7. Results were categorized in "clinical success", "NMR success" and "combined success" when symptoms decreased or disappeared, the lesion stabilized by NMR, or both, respectively. Overall, the corresponding figures were 80%, 76.6%, and 63.3%, and were remarkably influenced by the NMR grading of the lesion.

Adult↗
PubMed1996

Weak electromagnetic fields increase the amplitude of the pattern reversal VEP response in patients with multiple sclerosis.

Visual evoked potential (VEP) studies are widely used for the diagnosis of multiple sclerosis (MS) and are also useful in monitoring the effects of various therapeutic modalities in the disease. Brief, extracerebral applications of picotesla (pT) range flux intensity electromagnetic fields (EMFs) of low frequency have been shown efficacious in the treatment of motor and cognitive symptoms in MS implying that this treatment modality improves action potential transmission in demyelinating pathways. This report documents three MS patients with a remitting-progressive course in whom two successive brief extracerebral applications of pT range EMFs caused an immediate increase (and normalization) of the amplitudes of the visual evoked response in the eye previously affected by optic neuritis. However, the pretreatment prolonged latencies of the evoked responses remained essentially unchanged after the administration of EMFs. Since the latency of the VEP reflects the degree of conduction velocity and the amplitude the degree of conduction block in demyelinating optic pathways, the report demonstrates that extracerebral applications of these EMFs may rapidly reverse conduction block in demyelinating fibers. Reversal of the conduction block, which is though to be related to changes in axonal Na+ and K+ channels and synaptic neurotransmitter release, accounts for the immediate improvement of vision and other neurological deficits observed in MS patients following exposure to these EMFs.

Electromagnetic Fields↗