Studies on microwaves in medicine and biology: from snails to humans

Discrimination and quantification of live/dead rat brain cells using a non-linear segmentation model

The automatic cell analysis method is capable of segmenting the cells and can detect the number of live/dead cells present in the body. This study proposed a novel non-linear segmentation model (NSM) for the segmentation and quantification of live/dead cells present in the body. This work also reveals the aspects of electromagnetic radiation on the cell body. The bright images of the hippocampal CA3 region of the rat brain under the resolution of 60 × objective are used to analyze the effects called NISSL-stained dataset. The proposed non-linear segmentation model segments the foreground cells from the cell images based on the linear regression analysis. These foreground cells further get discriminated as live/dead cells and quantified using shape descriptors and geometric method, respectively. The proposed segmentation model is showing promising results (accuracy, 82.82%) in comparison with the existing renowned approaches. The counting analysis of live and dead cells using the proposed method is far better than the manual counts. Therefore, the proposed segmentation model and quantifying procedure is an amalgamated method for cell quantification that yields better segmentation results and provides pithy insights into the analysis of neuronal anomalies at a microscopic level. Graphical Abstract Resultant View of the overall proposed approach.

Highly stable microwave susceptible agents via encapsulation of Ti-mineral superfine powders in urea-formaldehyde resin microcapsules for tumor hyperthermia therapy

In this study, Ti-mineral superfine powders (Ti-MSP) encapsulated in urea-formaldehyde resin microcapsules (Ti-MSP@UF-MC) were successfully prepared via a one-step microemulsion method for the first time. Because of the strong confinement effects, the Ti-MSP@UF-MC possessed perfect microwave heating effects. The temperature was 9.3 °C higher than that of the saline solution, superior to UF-MC (no significant microwave heating effect, 0 °C) and Ti-MSP (5.1 °C). The Ti-MSP@UF-MC showed low toxicity and good biocompatibility via a series of studies, including a hemolysis study and the MTT assay in vitro and in vivo. When the concentration was below 1000 μg mL(-1), the hemolysis rate was lower than 5% (hemolysis study). When the concentration was below 400 μg mL(-1), the cell activity was higher than 80% (MTT assay). Moreover, the Ti-MSP@UF-MC exhibited an ideal CT imaging effect in vivo owing to the large molecular weight of Ti-MSP. The Ti-MSP@UF-MC showed a favorable microwave therapy effect in vivo. Using mice bearing H22 tumor cells as an animal model, the tumor suppression rate could reach 100%.

Noninvasive assessment of metabolic effects of exposure to 900 MHz electromagnetic fields on Djungarian Hamsters ( Phodopus sungorus )

Sixteen male Djungarian hamsters, serving as their own controls, were individually exposed to RF-EMF (900 MHz, GSM modulation) at 0 (sham), 0.08, 0.4 or 4 W/kg specific absorption rate (SAR) in specially constructed rectangular waveguides. Exposure duration was one week per condition, followed by one week without exposure. Once per day, the temperatures of the hamsters' back fur (a surrogate for skin temperature) and the cornea of the eye (a surrogate for body temperature), were measured by infrared thermography. Oxygen, carbon dioxide and humidity were measured continuously in the ambient and exhaled air. Food and water consumption, as well as body weight were recorded once per week. Only at the highest SAR level were the following effects observed: fur temperatures were elevated by approximately 0.5°C (P < 0.001), while the temperatures of the eyes' surface were not affected; food consumption was lowered (P < 0.05), while water consumption and body weight were not affected; the production of carbon dioxide was lowered during the day (P < 0.01) and unaffected during the night, while oxygen consumption levels remained unaffected and finally the respiratory quotient (carbon dioxide production divided by oxygen consumption) was lower during the day (P < 0.05) and also somewhat lower during the night (not significant). The results demonstrate the usefulness of our methods for experiments dealing with metabolic effects of RF-EMF exposure in rodents. They also confirm the assumption that even though the metabolism is reduced at high SAR levels, the body core temperature is being kept constant by the energy uptake from the RF-EMF exposure which is able to physiologically compensate for the reduced metabolism.

Microwave liver ablation: influence of hepatic vein size on heat-sink effect in a porcine model

PURPOSE

To determine influence of hepatic vein size on perfusion-mediated attenuation in adjacent microwave thermal ablation.

MATERIALS AND METHODS

With approval of the institutional animal research committee, seven Yorkshire pigs underwent percutaneous (n = 2) or open (n = 5) microwave liver ablation under general anesthesia. In each, multiple ultrasound-guided, nonoverlapping thermal lesions were created within 1 cm of hepatic veins in a 5-10-minute ablation at 45 W. After euthanasia, the liver was harvested and sectioned at 0.5-cm intervals and the degree of perivascular coagulation attenuation was graded on histopathologic analysis. Correlation between venous size (small, < or =3 mm; medium, 3-6 mm; and large, >6 mm) and attenuation grade was performed with use of the Spearman rank test.

RESULTS

In 63 of 103 sections (61%)--29 of 37 (78%) small, 27 of 48 (56%) medium, and seven of 18 (39%) large veins--the thermal injury extended to the vein wall around the entire circumference of the coagulation front without distortion of the ablation margin. In 40 of 103 sections (38.9%), varying degrees of concave distortion of perivenous ablation margins were noted, with significant correlation between vein size and heat-sink extent (P < .01). However, thermal injury extended to the vascular wall in all sections without complete circumferential sparing of liver tissue. Around two thrombosed veins, thermal lesions encased the vessels, producing paradoxically convex ablation margins.

CONCLUSIONS

Although the heat-sink effect was significantly dependent on hepatic vein size, the majority of pathologic sections exhibited no or minimal effect. Further study is required to assess clinical implications.

[Proposal for magnetic/electromagnetic fields protection norms on national level]

INTRODUCTION

The modern life is not possible without application of magnetic/electromagnetic fields, which can be both helpful and harmful for human body.

INFLUENCE OF MAGNETIC/ELECTROMAGNETIC FIELDS ON BIOLOGICAL SYSTEMS

The non-ionizing radiation, especially magnetic/electromagnetic fields of all frequencies (0-300 GHz), can have many harmful effects on the human health that is confirmed by numerous epidemiological studies, studies with volunteers, animal studies, and in vitro studies. Proposal for magnetic/electromagnetic fields protection norms on national level based on the WHO Program for Environment, International Commission on Non-Ionizing Radiation Protection (ICNIRP)], and WHO International EMF Project.

CONCLUSION

Protection from harmful effects of the magnetic/electromagnetic fields is still a great problem in many countries of modern society--huge costs, impaired quality of life, and more important, damage to the human health. Numerous data and publications of harmful effects of the magnetic/electromagnetic fields represents one's country basic necessary documentation for making decisions and law documents for protection norms on national level concerning the health maintenance according to the ICNIRP normatives.

Hearing of microwave pulses by humans and animals: effects, mechanism, and thresholds

The hearing of microwave pulses is a unique exception to the airborne or bone-conducted sound energy normally encountered in human auditory perception. The hearing apparatus commonly responds to airborne or bone-conducted acoustic or sound pressure waves in the audible frequency range. But the hearing of microwave pulses involves electromagnetic waves whose frequency ranges from hundreds of MHz to tens of GHz. Since electromagnetic waves (e.g., light) are seen but not heard, the report of auditory perception of microwave pulses was at once astonishing and intriguing. Moreover, it stood in sharp contrast to the responses associated with continuous-wave microwave radiation. Experimental and theoretical studies have shown that the microwave auditory phenomenon does not arise from an interaction of microwave pulses directly with the auditory nerves or neurons along the auditory neurophysiological pathways of the central nervous system. Instead, the microwave pulse, upon absorption by soft tissues in the head, launches a thermoelastic wave of acoustic pressure that travels by bone conduction to the inner ear. There, it activates the cochlear receptors via the same process involved for normal hearing. Aside from tissue heating, microwave auditory effect is the most widely accepted biological effect of microwave radiation with a known mechanism of interaction: the thermoelastic theory. The phenomenon, mechanism, power requirement, pressure amplitude, and auditory thresholds of microwave hearing are discussed in this paper. A specific emphasis is placed on human exposures to wireless communication fields and magnetic resonance imaging (MRI) coils.

Cell Biology of the Neurovascular Unit: Implications for Drug Delivery Across the Blood–Brain Barrier

The central nervous system (CNS) neurovascular unit is a dynamic structure consisting of vascular endothelial cells, pericytes, and closely juxtaposed astrocytes and neurons. Contact and communication events between cells of the neurovascular unit regulate CNS development, modulate cerebral blood flow, and influence permeability properties of the blood-brain barrier. Dysregulation of proper neurovascular unit function is linked to many common human CNS pathologies, making it a target for a variety of neurotherapeutic interventions. Furthermore, manipulation of the neurovascular unit to enhance the delivery of drugs to the CNS is an active area of interest. In this review I summarize current data concerning the cell and molecular biology of the neurovascular unit. Additionally, I suggest how manipulation of novel protein components of the neurovascular unit may enhance delivery of neurotherapeutic drugs across the blood-brain barrier.

Effects of 900 MHz electromagnetic fields exposure on cochlear cells' functionality in rats: Evaluation of distortion product otoacoustic emissions

In recent years, the widespread use of mobile phones has been accompanied by public debate about possible adverse consequences on human health. The auditory system is a major target of exposure to electromagnetic fields (EMF) emitted by cellular telephones; the aim of this study was the evaluation of possible effects of cellular phone-like emissions on the functionality of rat's cochlea. Distortion Products OtoAcoustic Emission (DPOAE) amplitude was selected as cochlea's outer hair cells (OHC) status indicator. A number of protocols, including different frequencies (the lower ones in rat's cochlea sensitivity spectrum), intensities and periods of exposure, were used; tests were carried out before, during and after the period of treatment. No significant variation due to exposure to microwaves has been evidenced.