Effect of temperature and mechanical strain on gastric epithelial cell line GSM06 wound restoration in vitro

BACKGROUND: The influence of the degree of cell differentiation and of physical stimulation on gastric mucosal wound healing is not completely understood. METHODS: A gastric mucosal cell line, GSM06, derived from the gastric mucosal cells of transgenic mice harbouring the simian virus 40 large T antigen, was cultured at 33 degrees C to make a confluent cell sheet. Artificial wounds of constant size were created. Wound healing was monitored at different temperatures (33, 37 and 39 degrees C), which altered the degree of differentiation. Cell proliferation was detected by bromodeoxyuridine staining. Mechanical strain was applied to adherent GSM06 cells after wounding in order to increase their length by an average of 5 or 10% at 5 cycles/min for 60 h. Repair of the wound was monitored every 12 h. RESULTS: Differentiated gastric epithelial cells showed a higher speed of migration. The number of proliferating cells around the wound was greatest at 33 degrees C and barely detectable at 39 degrees C. Under conditions of mechanical strain, the migration speed of differentiated cells (at 39 degrees C) slowed in a strain strength-dependent manner. CONCLUSIONS: It is suggested that cell differentiation status and physical stimulants might play a role in gastric wound healing in vivo by modifying cellular migration.     

Differences in carotid artery atherosclerosis between men and women in the early phase after ischemic event

Objectives

There is little data about sex differences in carotid atherosclerosis in the early phase after an ischemic event. The aim of this study was to examine the carotid artery atherosclerosis differences between men and women in early phase after TIA or stroke.

Mobile phone use and subjective symptoms. Comparison of symptoms experienced by users of analogue and digital mobile phones

In 1995 many people reported symptoms such as headaches, feelings of discomfort, warmth behind/around or on the ear and difficulties concentrating while using mobile phones. The number of complaints was higher for people using the digital (GSM) system, i.e. with pulse modulated fields, than for those using the analogue (NMT) system. Our main hypothesis was that GSM users experience more symptoms than NMT users. An epidemiological investigation was initiated including 6379 GSM users and 5613 NMT 900 users in Sweden, and 2500 from each category in Norway. The adjusted odds ratio did not indicate any increased risk for symptoms for GSM users compared with NMT 900 users. Our hypothesis was therefore disproved. However, we observed a statistically significant lower risk for sensations of warmth on the ear for GSM users compared with NMT 900 users. The same trend was seen in Norway for sensations of warmth behind/around the ear and in Sweden for headaches and fatigue. Factors distinguishing the two systems (radio frequency emission, phone temperatures and various ergonomic factors) may be responsible for these results, as well as for a secondary finding: a statistically significant association between calling time/number of calls per day and the prevalence of warmth behind/around or on the ear, headaches and fatigue.     

Effects of exposure to DAMPS and GSM signals on Ornithine Decarboxylase (ODC) activity: II. SH-SY5Y human neuroblastoma cells

Purpose: An increase in Ornithine Decarboxylase (ODC) activity was reported in L929 murine fibroblast cells after exposure to a digital cellular telephone signal. This result was not confirmed by several other studies, including the one reported in a companion paper. As a partner in the Perform-B programme, we extended this study to human neuroblastoma cells (SH-SY5Y), using well-defined waveguide systems to imitate exposure to radiofrequency radiation (RFR): Digital Advanced Mobile Phone System (DAMPS) or Global System for Mobile communications (GSM) signals emitted by mobile phones.

Materials and methods: Human neuroblastoma cells (SH-SY5Y) were exposed at various Specific Absorption Rates (SAR) to DAMPS or GSM signals using different set-ups. Cell ODC activities were assayed using ¹⁴CO₂ generation from ¹⁴C-labeled L-ornithine.

Results: SH-SY5Y cells were incubated for 20 hours, and were blindly exposed to 50 Hz-modulated DAMPS-835 or 217 Hz-modulated GSM-1800 for 8 or 24 h using Information Technologies in Society (IT'IS) waveguides equipped with fans. After cell lysis, ODC activity was determined using ¹⁴C-labeled L-ornithine. ODC activity was estimated by the ¹⁴CO₂ generated from ¹⁴C-labeled L-ornithine, as generated d.p.m. ¹⁴CO₂/h/mg protein. The results showed that, irrespective of the signal used (835 MHz/DAMPS, or 1800 MHz/GSM) and exposure conditions (duration and SAR), human SH-SY5Y neuroblastoma cells did not exhibit any alteration in ODC enzyme activity.

Conclusion: This work did not show a significant effect of mobile phone RFR exposure on ODC activity in neuroblastoma cells (SH-SY5Y).     

Electromagnetic field and brain development

Rapid advances in technology involve increased exposures to radio-frequency/microwave radiation from mobile phones and other wireless transmitting devices. As cell phones are held close to the head during talking and often stored next to the reproductive organs, studies are mostly focused on the brain. In fact, more research is especially needed to investigate electromagnetic field (EMF)’s effects on the central nervous system (CNS). Several studies clearly demonstrate that EMF emitted by cell phones could affect a range of body systems and functions. Recent work has demonstrated that EMF inhibit the formation and differentiation of neural stem cells during embryonic development and also affect reproductive and neurological health of adults that have undergone prenatal exposure. The aim of this review is to discuss the developing CNS and explain potential impacts of EMF on this system.     

远程胎心监护系统的设计

本文介绍一种基于单片机和GSM的远程胎心监护系统.系统由胎心检测装置和医院监护中心两部分组成.胎心检测数据通过GSM发送到医院监护中心,产科医生能及时将诊断信息反馈给孕妇.此装置能给孕妇带来方便与安全,有利于优生优育,具有积极的社会效益.     

Effects of Exposure to GSM Mobile Phone Cortisol,Alpha-Amylase,and Base Station Signals on Salivary Immunoglobulin A

Objective The present study aimed to test whether exposure to radiofrequency electromagnetic fields （RF-EMF） emitted by mobile phone base stations may have effects on salivary alpha-amylase, immunoglobulin A （IgA）, and cortisol levels. Methods Fifty seven participants were randomly allocated to one of three different experimental scenarios （22 participants to scenario 1, 26 to scenario 2, and 9 to scenario 3）. Each participant went through five 50-minute exposure sessions. The main RF-EMF source was a GSM-900-MHz antenna located at the outer wall of the building. In scenarios 1 and 2, the first, third, and fifth sessions were ＂low＂ （median power flux density 5.2 μW/m^2） exposure. The second session was ＂high＂ （2126.8 μW/m^2）, and the fourth session was ＂medium＂ （153.6 μW/m^2） in scenario 1, and vice versa in scenario 2. Scenario 3 had four ＂low＂ exposure conditions, followed by a ＂high＂ exposure condition. Biomedical parameters were collected by saliva samples three times a session. Exposure levels were created by shielding curtains. Results In scenario 3 from session 4 to session 5 （from ＂low＂ to ＂high＂ exposure）, an increase of cortisol was detected, while in scenarios 1 and 2, a higher concentration of alpha-amylase related to the baseline was identified as compared to that in scenario 3. IgA concentration was not significantly related to the exposure. Conclusions RF-EMF in considerably lower field densities than ICNIRP-gnidelines may influence certain psychobiological stress markers.     

Chronic exposure to GSM 1800-MHz microwaves reduces excitatory synaptic activity in cultured hippocampal neurons

The world wide proliferation of mobile phones raises the concern about the health effects of 1800-MHz microwaves on the brain. The present study assesses the effects of microwave exposure on the function of cultured hippocampal neurons of rats using whole cell patch-clamp analysis combined with immunocytochemistry. We showed that chronic exposure (15 min per day for 8 days) to Global System for Mobile Communication (GSM) 1800-MHz microwaves at specific absorption rate (SAR) of 2.4 W/kg induced a selective decrease in the amplitude of alpha-amino-3-hydroxy-5-methyl-4-soxazole propionic acid (AMPA) miniature excitatory postsynaptic currents (mEPSCs), whereas the frequency of AMPA mEPSCs and the amplitude of N-methyl-D-aspartate (NMDA) mEPSCs did not change. Furthermore, the GSM microwave treatment decreased the expression of postsynaptic density 95 (PSD95) in cultured neurons. Our results indicated that 2.4 W/kg GSM 1800-MHz microwaves may reduce excitatory synaptic activity and the number of excitatory synapses in cultured rat hippocampal neurons.