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result(s) for
"Johansson, Olle"
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Evaluation of Specific Absorption Rate as a Dosimetric Quantity for Electromagnetic Fields Bioeffects
by
Panagopoulos, Dimitris J.
,
Carlo, George L.
,
Johansson, Olle
in
Absorption
,
Analysis
,
Biological activity
2013
To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment.
We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect.
WE FIND THAT: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured.
SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict the biological effect due to non-linearity.
Journal Article
Cystic fibrosis transmembrane conductance regulator modulates enteric cholinergic activities and is abnormally expressed in the enteric ganglia of patients with slow transit constipation
2019
BackgroundCystic fibrosis transmembrane conductance regulator (CFTR) was recently found in the enteric nervous system, where its role is unclear. We aimed to identify which enteric neuronal structures express CFTR, whether CFTR modulates enteric neurotransmission and if altered CFTR expression is associated with slow transit constipation (STC).MethodsImmunofluorescence double labeling was performed to localize CFTR with various neuronal and glial cell markers in the human colon. The immunoreactivity (IR) of CFTR and choline acetyltransferase (ChAT) on myenteric plexus of control and STC colon was quantitatively analyzed. In control colonic muscle strips, electrical field stimulation (EFS) evoked contractile responses and the release of acetylcholine (ACh) was measured in the presence of the CFTR channel inhibitor, CFTR(inh)-172.ResultsCFTR-IR was densely localized to myenteric ganglia, where it was co-localized with neuronal markers HuC/D and β-tubulin, and glial marker S-100 but little with glial fibrillary acidic protein. Vesicular ACh transport was almost exclusively co-localized with CFTR, but neurons expressing nitric oxide synthase were CFTR negative. Significant reductions of CFTR-IR (P < 0.01) and ChAT-IR (P < 0.05) were observed on myenteric ganglia of STC compared to control. Pre-treatment of colonic muscle strips with CFTR(inh)-172 (10 µM) significantly inhibited EFS-evoked contractile responses (P < 0.01) and ACh release (P < 0.05).ConclusionsCo-localization of CFTR-IR with cholinergic markers, inhibition of EFS-induced colonic muscle contractility and ACh release by CFTR(inh)-172 suggest that CFTR modulates enteric cholinergic neurotransmission. The downregulation of CFTR and ChAT in myenteric ganglia of STC correlated with the impaired contractile responses to EFS.
Journal Article
Electrohypersensitivity: a functional impairment due to an inaccessible environment
by
Johansson, Olle
in
Economics
,
electrohypersensitivity
,
Electromagnetic Fields - adverse effects
2015
In Sweden, electrohypersensitivity is recognized as a functional impairment which implies only the environment as the culprit. The Swedish view provides persons with this impairment a maximal legal protection, it gives them the right to get accessibility measures for free, as well as governmental subsidies and municipality economic support, and to provide them with special Ombudsmen (at the municipality, the EU, and the UN level, respectively), the right and economic means to form disability organizations and allow these to be part of national and international counterparts, all with the simple and single aim to allow persons with the functional impairment electrohypersensitivity to live an equal life in a society based on equality. They are not seen as patients, the do not have an overriding medical diagnosis, but the ‘patient’ is only the inferior and potentially toxic environment. This does not mean that a subjective symptom of a functionally impaired can not be treated by a physician, as well as get sick-leave from their workplace as well as economic compensation, and already in the year 2000 such symptoms were identified in the Internal Code of Diagnoses, version 10 (ICD-10; R68.8/now W90), and have been since. But the underlying cause still remains only the environment.
Journal Article
Increased nerve growth factor and its receptors in atopic dermatitis: an immunohistochemical study
by
Hagströmer, Lena
,
Dou, Ying-Chun
,
Emtestam, Lennart
in
Adult
,
Allergic diseases
,
Atopic dermatitis
2006
Evidence suggests that neurotrophins may regulate certain immune functions and inflammation. In the present study, the localization and distribution of nerve growth factor (NGF) and its receptors were explored using immunohistochemical methods, with the aim of detecting the cause of the neurohyperplasia in early lesions of atopic dermatitis (AD). In AD involved skin, strong NGF-immunoreactive (IR) cells were observed in the epidermis. In some cases, a huge number of infiltrating cells with stronger NGF immunoreactivity was seen mainly in the dermal papillae. Some trkA immunoreactivity was observed in the outer membrane of cells in the basal and spinal layers of the epidermis. In the papillary dermis, a larger number of cells demonstrated strong trkA immunoreactivity. The p75 NGFr-IR nerve fibre profiles were increased (900 per mm(2); p<0.001) compared to normal [the involved skin also differed from the uninvolved skin (p<0.05)] in the dermal papillae. These nerve fibres were larger, coarser and branched, some of them terminated at p75 NGFr-IR basal cells, and also revealed a stronger fluorescence staining than the controls or the uninvolved skin. In normal healthy volunteers and AD uninvolved skin, the NGF immunoreactivity was weak in the basal layer of epidermis. Only a few trkA positive cells were seen in the basal layer of the epidermis and upper dermis. The IR epidermal basal cells revealed a striking patchy arrangement with strong p75 NGFr immunostaining in the peripheral part of the cells, and short and thick NGFr-IR nerve fibre profiles appeared as smooth endings scattered in the dermis including the cutaneous accessory organs. Using NGF and p75 NGFr double staining, both immunoreactivities showed a weak staining in the epidermis and dermis in normal and uninvolved skin. In the involved dermis of AD, the intensity of p75 NGFr-IR nerves was stronger in areas where there were also increased numbers of NGF-IR cells. These findings indicate that NGF and its receptors may contribute to the neurohyperplasia of AD.
Journal Article
Multiple Transcoding Impact on Speech Quality in Ideal Network Conditions
2015
This paper deals with the impact of transcoding on the speech quality. We have focused mainly on the transcoding between codecs without the negative influence of the network parameters such as packet loss and delay. It has ensured objective and repeatable results from our measurement. The measurement was performed on the Transcoding Measuring System developed especially for this purpose. The system is based on the open source projects and is useful as a design tool for VoIP system administrators. The paper compares the most used codecs from the transcoding perspective. The multiple transcoding between G711, GSM and G729 codecs were performed and the speech quality of these calls was evaluated. The speech quality was measured by Perceptual Evaluation of Speech Quality method, which provides results in Mean Opinion Score used to describe the speech quality on a scale from 1 to 5. The obtained results indicate periodical speech quality degradation on every transcoding between two codecs.
Journal Article
Polarization: A Key Difference between Man-made and Natural Electromagnetic Fields, in regard to Biological Activity
by
Panagopoulos, Dimitris J.
,
Carlo, George L.
,
Johansson, Olle
in
631/57/2270/1140
,
639/766/747
,
692/499
2015
In the present study we analyze the role of polarization in the biological activity of Electromagnetic Fields (EMFs)/Electromagnetic Radiation (EMR). All types of man-made EMFs/EMR - in contrast to natural EMFs/EMR - are polarized. Polarized EMFs/EMR can have increased biological activity, due to: 1) Ability to produce constructive interference effects and amplify their intensities at many locations. 2) Ability to force all charged/polar molecules and especially free ions within and around all living cells to oscillate on parallel planes and in phase with the applied polarized field. Such ionic forced-oscillations exert additive electrostatic forces on the sensors of cell membrane electro-sensitive ion channels, resulting in their irregular gating and consequent disruption of the cell’s electrochemical balance. These features render man-made EMFs/EMR more bioactive than natural non-ionizing EMFs/EMR. This explains the increasing number of biological effects discovered during the past few decades to be induced by man-made EMFs, in contrast to natural EMFs in the terrestrial environment which have always been present throughout evolution, although human exposure to the latter ones is normally of significantly higher intensities/energy and longer durations. Thus, polarization seems to be a trigger that significantly increases the probability for the initiation of biological/health effects.
Journal Article
Radiofrequency exposure in young and old: different sensitivities in light of age-relevant natural differences
2015
Our environment is now permeated by anthropogenic radiofrequency electromagnetic radiation, and individuals of all ages are exposed for most of each 24 h period from transmitting devices. Despite claims that children are more likely to be vulnerable than healthy adults to unwanted effects of this exposure, there has been no recent examination of this, nor of comparative risk to the elderly or ill. We sought to clarify whether research supports the claim of increased risk in specific age-groups. First, we identified the literature which has explored age-specific pathophysiological impacts of RF-EMR. Natural life-span changes relevant to these different impacts provides context for our review of the selected literature, followed by discussion of health and well-being implications. We conclude that age-dependent RF-EMR study results, when considered in the context of developmental stage, indicate increased specific vulnerabilities in the young (fetus to adolescent), the elderly, and those with cancer. There appears to be at least one mechanism other than the known thermal mechanism causing different responses to RF-EMR depending upon the exposure parameters, the cell/physiological process involved, and according to age and health status. As well as personal health and quality-of-life impacts, an ageing population means there are economic implications for public health and policy.
Journal Article
The human immune system’s response to carcinogenic and other infectious agents transmitted by mosquito vectors
2017
It has been hypothesised that mosquitoes [Diptera: Culicidae] may play more of a role in certain cancers than is currently appreciated. Research links 33 infectious agents to cancer, 27 of which have a presence in mosquitoes, and that, in addition, mosquito saliva downregulates the immune system. The objective of this paper is to review the literature on the immune system and cancer-causing infectious agents, particularly those present in mosquitoes, with a view to establishing whether such infectious agents can, in the long run, defeat the immune system or be defeated by it. Many of the viruses, bacteria and parasites recognised by the International Agency for Research on Cancer (IARC) as carcinogenic and suspected by others as being involved in cancer have evolved numerous complex ways of avoiding, suppressing or altering the immune system’s responses. These features, coupled with the multiplicity and variety of serious infectious agents carried by some species of mosquitoes and the adverse effects on the immune system of mosquito saliva, suggest that post-mosquito bite the immune system is likely to be overwhelmed. In such a situation, immunisation strategies offer little chance of cancer prevention, unless a single or limited number of critical infectious agents can be isolated from the ‘mosquito’ cocktail. If that proves to be impossible cancer prevention will, therefore, if the hypothesis proves to be correct, rest on the twin strategies of environmentally controlling the mosquito population and humans avoiding being bitten. The latter strategy will involve determining the factors that demark those being bitten from those that are not.
Journal Article
Increased nerve growth factor- and tyrosine kinase A-like immunoreactivities in prurigo nodularis skin – an exploration of the cause of neurohyperplasia
by
Johansson, Olle
,
Emtestam, Lennart
,
Liang, Yong
in
Aged
,
Axons
,
Biological and medical sciences
2002
Neurotrophins and their receptors play an important role in cutaneous nerve development and reconstruction after injury. Recent developments indicate that this group of molecules not only exert a neurotrophic action, but are also involved in immune responses and inflammation. Prurigo nodularis is a skin disease characterized by neurohyperplasia and intense itch. In the present study, the localization and distribution of nerve growth factor (NGF) and its receptors were explored by immunohistochemical methods, with the aim of detecting the cause of the neurohyperplasia in the disease. In normal healthy volunteers and in uninvolved skin, NGF immunoreactivity was seldom seen in the basal layer of the epidermis or in the dermis. In prurigo nodularis skin, there was also very little NGF immunoreactivity in the epidermis. However, in the dermis, a huge number of cells showed an NGF-like immunoreactivity. In normal skin of healthy volunteers, only a weak staining for tyrosine kinase A (trkA) was seen in the epidermis, whereas in the dermis, there was no trkA staining seen at all. However, in the prurigo nodularis tissue, the hyperplastic nerves clearly showed trkA immunoreactivity, and it seemed that the staining was only present in the axons. By NGF and p75 NGF receptor double-labelling, both immunoreactivities showed weak staining in the epidermis and dermis of normal skin. However, in the dermis of prurigo nodularis, strong staining for both NGF and NGF receptor antibodies was seen. NGF receptor-immunoreactive nerves were more dense in areas where there were more NGF-immunoreactive cells. The results indicate that in prurigo nodularis skin, NGF is overexpressed, locally infiltrated inflammatory cells may be the source of this NGF, and NGF and its receptors may contribute to the neurohyperplasia of the disease.
Journal Article
Real versus Simulated Mobile Phone Exposures in Experimental Studies
by
Panagopoulos, Dimitris J.
,
Carlo, George L.
,
Johansson, Olle
in
Adaptation
,
Animals
,
Biological activity
2015
We examined whether exposures to mobile phone radiation in biological/clinical experiments should be performed with real-life Electromagnetic Fields (EMFs) emitted by commercially available mobile phone handsets, instead of simulated EMFs emitted by generators or test phones. Real mobile phone emissions are constantly and unpredictably varying and thus are very different from simulated emissions which employ fixed parameters and no variability. This variability is an important parameter that makes real emissions more bioactive. Living organisms seem to have decreased defense against environmental stressors of high variability. While experimental studies employing simulated EMF-emissions present a strong inconsistency among their results with less than 50% of them reporting effects, studies employing real mobile phone exposures demonstrate an almost 100% consistency in showing adverse effects. This consistency is in agreement with studies showing association with brain tumors, symptoms of unwellness, and declines in animal populations. Average dosimetry in studies with real emissions can be reliable with increased number of field measurements, and variation in experimental outcomes due to exposure variability becomes less significant with increased number of experimental replications. We conclude that, in order for experimental findings to reflect reality, it is crucially important that exposures be performed by commercially available mobile phone handsets.
Journal Article