| 51. |
- Persson, Bertil R, et al.
(författare)
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Immunization with syngeneic interferon-gamma (IFN-g) secreting tumour cells enhance the Therapeutic effect and Abscopal effect from combined treatment of subcutaneously implanted contra-lateral N29 tumours on Fischer rats with Pulsed electric fields (PEF) and 60Co-gamma radiation.
- 2014
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2014:002, s. 1-30
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study is to study the Abscopal regression of subcutaneously implanted N29 rat glioma after immunization with syngeneic IFNg secreting cells and treatment of contra-lateral tumours with pulsed electric fields (PEF) and/or radiation therapy (RT). The study was performed on rats of the Fischer-344 strain with rat glioma N29 tumours implanted subcutaneously on the flank or on both the right treated hind leg and the left untreated hind leg. Once weekly for three weeks, the animals were given intra-peritoneal injections of irradiated, modified N29 tumour cells, secreting interferon-gamma (IFN-g). PEF was given with 16 exponentially decaying pulses at a maximum electric fields strength of 1400 V/cm and t1/e= 1 ms. RT was given with 60Co gamma radiation at daily fractions of 5 Gy, to a total absorbed dose of 20 Gy. The animals were arranged into controls and groups of various treatments: PEF, RT, PEF+RT and immunization (IFNg). Fitting the data obtained from consecutive measurements of tumour volume (TV) of each individual tumour to an exponential model TV = TV0*exp[TGR*t] estimated the tumours growth rate (TGR %per day) after the day of treatment (t = 0). TGR of the right-lateral treated tumour was significantly decreased for independent treatments with PEF and RT and with the combined treatment PEF+RT. With immunization (IFNg) alone and in combination with PEF there was, however, no significant decrease of the TGR of the right-lateral tumours. But in the combination of immunization with RT or PEF+RT there was a highly significant decrease of the TGR values. The Abscopal effect was evaluated by comparing the growth rate of the untreated contra lateral tumours with the treated tumours. TGR of the left-lateral untreated tumour in the groups with independent treatment of right-lateral tumours with PEF, was not significantly reduced. But the TGR values are significantly reduced in the group of rats treated with RT and the combination PEF + RT. With IFNg alone and in combinations with PEF or RT there was no significant decrease of the TGR in the left lateral tumours. But in the combination of IFNg with PEF+RT there was a highly significant decrease of the TGR values in the left lateral tumours. The specific therapeutic effect (STE = 1 - TGRExposed/ TGRCtrl ) after treatments with PEF was 0.30±0.01 and after RT 0.46±0.04 and after the combination PEF+RT 0.36+/- 0.08. After immunization with IFNg secreting tumour cells the STE 0.09+/- 0.07 is not significantly different from zero. Also for the combination of immunization and PEF the STE value of 0.07+/- 0.07 is not significantly different from zero. In the combination of immunization with RT the STE value was 0.32+/- 0.01 that is significantly different from zero and only slightly lower than for RT alone. The STE of the combination of immunization with (PEF+RT) resulted in an unexpectedly high STE value of 0.70+/- 0.08 that is highly significantly different from zero (p < 0.0001). The specific Abscopal effect (SAE = 1 - TGRUn-Exposed/ TGRCtrl ) of the contra lateral unexposed tumours in rats treated with PEF or RT are both significantly different from zero. For RT the average SAE value is 0.33+/- 0.04 and for PEF it is 0.11+/- 0.05. The SAE value for the combined treatment with PEF + RT is 0.26+/- 0.02 that is about the same as for RT alone. For immunization with IFNg secreting tumour cells only and IFNg +PEF the SAE values were not significantly different from zero. But IFNg combined with RT result in a SAE value of 0.18±0.12 and the combination of IFNg with PEF+RT results in an improved abscopal effect with the SAE value of 0.33+/- 0.06. After combined treatment with PEF + RT the average of the therapeutic enhancement ratio (TER = STEExperimental / STEIndependent) is 0.47 +/- 0.12 and the abscopal enhancement ratio (AER = SAEExperimental / SAEIndependent) is 0.61 +/- 0.1 respectively. With all three treatment modalities combined IFNg + PEF + RT and all combinations of independent treatments with PEF, RT or IFNg are considered, the average of the TER is 1.20+/- 0.15 and AER is 1.22+/- 0.20. This might indicate that there is a synergism on the tumours on both sides by combining PEF, RT and immunization with IFNg secreting cells. These results were first presented Nov 21-24, 2002, as Poster at Society of Neuro-Oncology (SNO) Annual Meeting, San Diego, USA (Persson et al 2002).
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| 52. |
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| 53. |
- Danielsson, Hans, et al.
(författare)
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Test of an empirical method for ozone detection in the stratosphere using two filtered broadband UV-meters
- 2013
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2013:003, s. 1-20
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Tidskriftsartikel (refereegranskat)abstract
- We describe a simple method to detect significant changes of the total ozone column from global (diffuse and direct) zenith sky measurements taken at the Earth’s surface. The calculation of the total ozone column relies on measured irradiance at two wavelengths in the ultra violet part of the solar spectrum. One of these (i.e. 306 nm) are appreciable absorbed by ozone whereas the other (i.e. 360 nm) is not. The method provides measurements for clear as well as for cloudy sky conditions. The natural logarithm of the irradiance ratio at the two wavelengths, corrected for solar elevation dependence, is assumed to be proportional to the amount of ozone in the atmospheric column. It is assumed that the two wavelengths have same properties in the atmosphere excluding the impact of ozone. Therefore variations in atmospheric conditions should cancel out in the ratio. We found a strong correlation between our calculated quantity and ozone measurements at The Danish Meteorological Institute, DMI, Copenhagen, Denmark, which is approximately 30 km away from the measuring site. The correlation coefficient, R, from linear regression had the value 0.90, and the standard deviation, Sres, for the residuals were 10.6 DU (Dobson Units), and the mean value was 322 DU, obtained from every day point measurements during the Swedish summer, total 67 days.
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| 54. |
- Ljungvall, Magnus, et al.
(författare)
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Treatment of brain tumours with electroporation and bleomycin in an in vivo rat model
- 2013
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2013:001, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to examine the possibilities of prolonging the life of rats with brain tumours using electroporation only while conducting impedance scans to evaluate the rate of electroporation. During the experiments, the treated rats in the first batch had tumors grow for 14 days and were then given electroporation with 8 + 8 exponential pulses at 800 v/cm, and 15 micro-F. Three of the animals given electroporation and bleomycin and one of the animals given electroporation alone died within three days of treatment. The reason for this may be oedema and increased intracranial pressure due to the large amount of energy delivered to the brain. In the second batch of rats given electroporation with 8 + 8 exponential pulses at 800 V/cm but with the lower capacitance setting of 4.5 micro-F, none of the treated rats died within a week after treatment. Among these rats, the tumors had also grown for only 10 days, thus further decreasing the risk of critical increases of the intracranial pressure directly after treatment. Interpretation of the impedance scans made before and after is made difficult due to factors such as possible short-circuiting of electrodes due to bleeding in the operating area. Not counting the rats in the first batch that died within three days of treatment, the rats treated with electroporation had a significantly prolonged life compared to controls. These results combined with results of a prior study of treatment of brain tumors in rats with electroporation in combination with Bleomycin suggest that this form of treatment may prolong the life of patients with brain tumours.
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| 55. |
- Persson, Bertil R
(författare)
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Transfer analysis of 210Po and 210Pb in the terrestrial environment
- 2013
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2013:002, s. 1-42
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Tidskriftsartikel (refereegranskat)abstract
- The transfer of 210Po and 210Pb between various compartments in the terrestrial environment has been analysed by using various published data. The average activity concentration of 210Po in soil is 61 ± 14 Bq.kg-1 d.w. with a median (50%) value of 44 Bq.kg-1 d.w. Ground water concentrations of 210Po in drilled wells might be as high as 6.5 Bq/l. But in regular drinking water it is just about 3-5 mBq/l. The uptake of radionuclides from soil to plant is usually given as the ratio of radionuclide activity concentration per unit mass concentrations (Bq.kg-1 dry w.) of plant (ACplant ) and soil (ACsoil ) respectively. This ratio is called the soil tranfer factor STF = ACplant / ACsoil. The soil transfer factor vaires widely beween various types of crops with an average about 0.056±0.003. Mean annual deposition and activity concentrations (mBq.l-1) of 210Pb 210Po and in rainwater varies with latitudes (0N to 0S) with longitudes (0W. 0E). Between latitudes 20 and 60 0N a linear relation between the yje activity concentration of 210Pb was found: A(210Pb) = 2.17 * (ON) - 22.2 (mBq.l-1). Lichens (Cladonia alpestris) collected at was used as a model for studying the sorpition and retention of atmospheric deposition in plants and the upper layer of soil. The atmospheric deposition of 210Pb and 210Po. however. also affect the activity concentrations in leafy plants. By comparing the activity concentrations in plants grown on an open field with those grown on a field sheltered by a polyethylene tent it has been possible to estimate a deposition transfer factor : DTF= Difference of the activity concentration in plants grown in open field (Deposition+Soil “ACDS”) and tent shelter (Soil “ACS”) respectively. divided by the atmospheric deposition “AD” during the vegetation period (Bq.m-2). The deposition transfer factor for 210Pb thus estimated is in the order of 0.5-1 (m2.Bq-1) for leafy plants like grass and 0.1-0.5 for less leafy plant and straw. For various grains it is < 0.2 (Barley grains 0.2; wheat grains <0.001.). For root fruits it is < 0.003 ( red beet 0.003; potatoes <0.001). Corresponding values for 210Po are about a factor 3 higher. The fraction of 210Pb firmly incorporated into the plant is about 82±20 % for atmospheric deposited 210Pb and 60±20 % for 210Pb taken up from soil. A few studies have been performed to quantitatively study the transfer of the natural radionuclides 210Pb and 210Po from fodder to milk. The activity concentration ratios between milk and various types of forage was estimated to 1.4±0.7 for 210Pb and 0.41±0.09 for 210Po. By assuming a daily food intake of 16 kg dry matter per day the transfer coefficient Fm. that describes the fraction of the daily intake of radionuclides that is secreted per litre of milk has been estimated from these studies. The transfer coefficient Fm for 210Pb thus obtained is 0.01±0.008 d.l-1 and for 210Po 0.003 ± 0.0007 d.l-1. These values are about 30 and 15 times higher than those estimated by IAEA for the elements respectively.
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| 56. |
- Ceberg, Crister, et al.
(författare)
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Photon activation therapy of RG2 glioma carrying Fischer rats using stable thallium and monochromatic synchrotron radiation.
- 2012
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 57:24, s. 8377-8391
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Tidskriftsartikel (refereegranskat)abstract
- 75 RG2 glioma-carrying Fischer rats were treated by photon activation therapy (PAT) with monochromatic synchrotron radiation and stable thallium. Three groups were treated with thallium in combination with radiation at different energy; immediately below and above the thallium K-edge, and at 50 keV. Three control groups were given irradiation only, thallium only, or no treatment at all. For animals receiving thallium in combination with radiation to 15 Gy at 50 keV, the median survival time was 30 days, which was 67% longer than for the untreated controls (p = 0.0020) and 36% longer than for the group treated with radiation alone (not significant). Treatment with thallium and radiation at the higher energy levels were not effective at the given absorbed dose and thallium concentration. In the groups treated at 50 keV and above the K-edge, several animals exhibited extensive and sometimes contra-lateral edema, neuronal death and frank tissue necrosis. No such marked changes were seen in the other groups. The results were discussed with reference to Monte Carlo calculated electron energy spectra and dose enhancement factors.
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| 57. |
- Gravé, Jan, et al.
(författare)
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STUDIES OF EFFECTS OF GSM-900 MICROWAVE EXPOSURE ON DNA ”MICRONUCLEUS” FORMATION IN MICE
- 2012
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2012:002, s. 1-15
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Possible genotoxic effects of microwave exposure from GSM-900 mobile telephones have investigated with in vivo micronucleus assay of mouse erythrocytes from CBA mice and GFAP knockout mice. No significant change in the frequency of erythrocytes with micronuclei neither in the young (polychromatic PCE) or mature (normichromatic NCE) erythrocytes. There is, however, a tendency but not significant to increased MPCE in female mice after 35 days of exposure. There is a marked tendency to lower PCE-fraction in the exposed groups. When male and female is studied separately there is no significant difference. However, if the values are normalised to eliminate the sex-difference there is a significant lower fraction in the exposed mice. Another observation is lower weight of the exposed male. If normalised data for both sexes are pooled there is an almost significant difference (95% level) in weight. We found a less pronounced difference in the CBE mice than in the GFAP experiment. Thus genotype might play a role in microwave exposure. Differences in exposure time and number of controls in GFAP and CBA experiment might influence the results. We observe a moderate decrease of formation of new erythrocytes in the exposed animals. This might fit the tendency of lower weight in the exposed animals and might indicate a general decreased cell-proliferation in the exposed animals.
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| 58. |
- Henricsson, Fredrik, et al.
(författare)
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Polonium-210 in the bio-sphere : Bio-kinetics and biological effects
- 2012
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Ingår i: Radionuclides : Sources, Properties and Hazards - Sources, Properties and Hazards. - 9781619427488 ; , s. 33-60
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Bokkapitel (refereegranskat)abstract
- Polonium-210 is an alpha particle emitting radioactive element with a half-life of 138 days. It appears at the end of the decay-chain of Uranium-238 where the long lived Lead-210 (22.3 a) decays to Bismuth-210, and finally Polonium-210. 210Po is introduced into the biosphere through various routes of terrestrial and marine radioecological pathways. The level of 210Po activity in drinking water (5 Bq.kg-1) and in most common food items of terrestrial origin are usually low (0.04-0.1 Bq.kg-1 wet mass) and considered to be without concerns for human health. In some terrestrial food items such as reindeer and caribou, high 210Po levels (10 Bq.kg-1 wet mass) are due to their habit of grazing lichens (250 Bq.kg-1 dry weight). The food chain lichen-reindeer and man in arctic and sub-arctic regions is a unique pathway of 210Po to man. The enhancement of 210Po concentrations is also very pronounced in marine organisms feeding upon phytoplankton at the base of the food chain. Fish and seafood therefore have high activity concentrations of 210Po (2-15 Bq.kg-1). The daily dietary intakes of 210Po vary widely around the world with an estimated average median of about 160mBq.day-1. That corresponds to annual effective doses of about 70μSv.a-1 for 210Po. Populations mainly living on reindeer meat or marine food have a 5-10 fold higher annual effective doses. High activity concentrations (13 ± 3 Bq.kg-1) of Po-210 and Pb-210 are found in tobacco and its products. The annual effective radiation dose from 210Po for the whole body of a smoker who smokes 20 cigarettes per day has been estimated to 400μSv.a-1. The concentrations of 210Po in the air-ways and the lung tissues caused by smoking of tobacco contributes to a high radiation adsorbed dose to the respiratory epithelium, which contribute to the increased incidence of lung cancer observed among smokers, In December of 2006, former Russian intelligence operative Alexander Litvinenko died by what proved to be ingestion of polonium-210. This incident brought with it an increased interest of the bio-kinetics and radio-toxicity of 210Po. Alpha particles have a greater relative biological effectiveness (RBE) than gamma and X-rays considering cancer induction. But there are still no significant proofs in terms of increased risk in humans of in vivo bystander effects of 210Po alpha particle radiation. More work has to been done in studying RBE and the mechanism of the bystander effect and its relevance to cancer induction in man.
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| 59. |
- Nittby, Henrietta, et al.
(författare)
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Analgetic effects of non-thermal GSM-1900 radiofrequency electromagnetic fields in the land snail Helix pomatia
- 2012
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 88:3, s. 245-252
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Tidskriftsartikel (refereegranskat)abstract
- Purpose : To investigate whether mobile phone radiation might affect snail nociception, employing radiofrequency (RF) electromagnetic fields (EMF) which, to our knowledge, have hitherto not been studied in a snail model. Exposure to extremely low frequency (ELF) magnetic fields has however been shown to significantly affect nociceptive responses. Materials and methods : In the present study, we exposed 29 land snails of the strain Helix pomatia to global system for mobile communications (GSM) EMF at 1900 MHz at the non-thermal level 48 mW/kg for 1 hour each and 29 snails were sham controls. The experiments took place during the onset of summer, with all snails being well out of hibernation. Before and after GSM or sham exposure, the snails were subjected to thermal pain by being placed on a hot plate. The reaction time for retraction from the hot plate was measured by two blinded observers. Results : Comparing the reaction pattern of each snail before and after exposure, the GSM-exposed snails were less sensitive to thermal pain as compared to the sham controls, indicating that RF exposure induces a significant analgesia (Mann-Whitney p < 0.001). Conclusion : This study might support earlier findings, describing beneficial effects of EMF exposure upon nociception.
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| 60. |
- Persson, Bertil R, et al.
(författare)
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Non-thermal" Effects on the Blood-Brain Barrier in Fischer rats by exposure to microwaves
- 2012
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2012-006:006, s. 1-39
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Effect of 915 MHz electromagnetic fields (EMF) on the blood brain-barrier (BBB) permeability has been studied in Fischer 344 rats of both sexes. Male and female Fischer 344 rats were exposed in a Transverse Electromagnetic Transmission line chamber to microwaves of 915 MHz as continuous wave (CW) and pulse-modulated with different pulse power and at various time intervals. The CW-pulse power varied from 0.001W to 10 W and the exposure time from 2 min. to 960 min. In each experiment we randomly placed 4 rats in excited and 4 control rats in non-excited TEM-cells respectively. The rats were not anaesthetised during the exposure. The rats were exposed to 915 MHz microwaves, either continuous wave (CW) or pulse modulated at 4,8,16 or 217 Hz with 0.57 ms pulse width, or pulse modulated at 50 Hz with 6.6 ms pulse width as well as from a real GSM-900 telephone. All animals were sacrificed by perfusion-fixation of the brains under chloralhydrate anaesthesia after the exposure. The brains were then perfused, first with saline for 3-4 minutes, and then with 4% formaldehyde for 5-6 minutes. Whole coronal sections of the brains were dehydrated and embedded in paraffin and sectioned at 5 μm. The degree of albumin leakage was demonstrated immune-histo-chemically and classified in order of increased number of albumin extravasations by a rank number: 0 - 0.5 - 1.0 - 1.5 - 2 - 3. Pathological albumin leakage was judged as albumin extravasations equal to or larger than 1. The frequency of pathological rats in all control groups was about 17%. Among rats exposed to pulse modulated microwaves the ratio of pathological rats was 170/481(0.35±0.03) and among rats exposed to continuous wave exposure (CW) it was 74/149 (0.50±0.07). These results are both highly significantly different to their corresponding controls (p<0.0001). The rats were exposed to SAR various values: 0.2; 2; (20-40); (100-500); (1000-3000) mW/kg. In the 217 Hz modulated group (GSM simulated) we found the most increased ratio of albumin extravasations OR= 4 at 0.2 mW/kg. But no significant increased ratio at SAR 2000 mW/kg. The response curve of OR versus log(SAR) had the shape of a bathtub, with a minimum at a100 mW/kg. A similar curve was recorded for OR versus Specific Absorbed Energy (SAE Joule / kg) with a minimum at 100 J/kg. Similar response curves were recorded for the various modulation frequencies 4; 8; 16; 50 Hz. We found no pronounced difference between the various modulation frequencies other than the effect of CW exposure seems to be more effective than pulse modulated exposure in opening the BBB at high SAR values 100-2000 mW/kg. Conclusion: The opening of the BBB is most effective at SAR values in the range of 0.1-0.5 mW.kg-1 and less effective in the range of 50-500 mW.kg-1. In this low SAR range thermal effects are unlikely. Thus there seems to be a non-thermal mechanism involved triggering the opening of the BBB.
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