Microwave applications in neuromorphology and neurochemistry: safety precautions and techniques

Brain Glycogen Structure and Its Associated Proteins: Past, Present and Future

This chapter reviews the history of glycogen-related research and discusses in detail the structure, regulation, chemical properties and subcellular distribution of glycogen and its associated proteins, with particular focus on these aspects in brain tissue.

Microwave irradiation enhances gene and oligonucleotide delivery and induces effective exon skipping in myoblasts

Microwave (MW) energy consists of electric and magnetic fields and is able to penetrate deep into biological materials. We investigated the effect of MW (2450 MHz) irradiation on gene delivery in cultured mouse myoblasts and observed enhanced transgene expression. This effect is, however, highly variable and critically dependent on the power levels, duration and cycle conditions of MW exposure. MW irradiation greatly enhances delivery of 2'O methyl-phosphorothioate antisense oligonucleotide (AON) targeting mouse dystrophin exon 23 and induces specific exon skipping in cultured myoblasts. Effective delivery of AON by MW irradiation is able to correct the dystrophin reading frame disrupted by a nonsense point mutation in the H2K mdx myoblasts, resulting in the restoration of dystrophin expression. MW-mediated nucleic acid delivery does not directly link to the increase in system temperature. The high variability in gene and oligonucleotide delivery is most likely the result of considerable irregularity in the distribution of the energy and magnetic field produced by MW with the current device. Therefore, achieving effective delivery of the therapeutic molecules would require new designs of MW devices capable of providing controllable and evenly distributed energy for homogenous exposure of the target cells.

Effect of microwave electromagnetic field on skeletal muscle fibre activity

The aim of the present study was to investigate the influence of microwave irradiation on fatiguing activity of isolated frog skeletal muscle fibres. The changes in the electrical and mechanical activity were used as criteria for the exposure effects. Repetitive suprathreshold stimulation with interstimulus interval of 200 ms for 3 min was applied. Intracellular (ICAP) and extracellular (ECAP) action potentials and twitch contractions (Tw) of muscle fibres after 1 hour microwave exposure (2.45 GHz, 20 mW/cm( 2) power density) were compared with those recorded after one hour sham exposure (control). The duration of uninterrupted activity in the trial (endurance time; ET) was not significantly affected by microwave field exposure. After microwave irradiation, the ICAP amplitude was higher, the rising time was shorter, and the resting membrane potential was more negative compared to controls. There was a slower rate of parameters changes during ET in potentials obtained from irradiated fibres. Microwave exposure increased the propagation velocity of excitation, the ECAP and Tw amplitudes, as well as shortened their time parameters. We concluded that a 2.45 GHz microwave field possesses a stimulating effect on muscle fibre activity, which is in part due to its specific, non-thermal properties. The microwave induced-changes in muscle fibre activity may reduce development of skeletal muscle fatigue.

Safranin O staining using a microwave oven

We investigated the effects of microwave irradiation on a safranin O staining method for paraffin sections of formalin fixed rabbit larynx. The control sections were stained according to the conventional method, and the experimental sections were stained in microwave oven for 10 sec at 360 W in Weigert's iron hematoxylin, and for 30 sec at 360 W in fast green and 0.1% safranin O staining solutions. Light microscopic examination of the sections revealed that the microwave heating did not adversely affect the staining properties of cartilage tissue compared to the conventional staining method. Small differences such as darker staining of the matrix and shrinkage of the cytoplasm was observed in some microwave treated sections. The present study revealed that microwave application can be used safely for the safranin O method with the advantage of reduced staining time.