| 61. |
- Persson, Bertil R, et al.
(författare)
-
Studies of 1H-NMR Relaxation Dispersion in Human Brain- tissue Samples: Implications for Magnetic Resonance Relaxation Dispersion Imaging (MARDI)
- 2012
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2012:001, s. 1-22
-
Tidskriftsartikel (refereegranskat)abstract
- Studies of 1H-NMR Relaxation Dispersion in Human Brain- tissue Samples: Implications for Magnetic Resonance Relaxation Dispersion Imaging (MARDI) Bertil R.R. Persson1, Lars Malmgren1,2 and Leif G. Salford3 1Medical Radiation Physics 2MAX Laboratory 3Dept. of Neurosurgery, Lund University, Lund Sweden [Bertil R.R. Persson, Lund University, Dept. of medical radiation physics, Barngatan 2, S-22185 Lund Sweden] bertil_r.persson@med.lu.se Abstract. In order to analyze the relaxation characteristics in fresh human brain tissue and blood samples we studied the proton relaxation rate dispersion in the frequency interval from 0.01 to 10 MHz. With the Field cycling method we apply, the sample is first magnetized in a relatively high magnetic fields (0.5 Tesla), which then by electronic means rapidly (10-3 s) is reduced to lower values (0.0001 - 0.5 Tesla) where the excited proton spin may relax during a time interval of about 3*T1max. Then the magnetic field is again quickly raised up to higher level for the detection of NMR-signal. In order to analyse the relaxation characteristics we applied a model with three compartments of water exchange. For each compartment we estimate a characteristic frequency by fitting the dispersion curves to a sum of Lorentz distributions. The characteristic frequencies thus obyained for various human yissuesater given in the following table. TissueFrequency n1 (low) / kHzFrequency n2 (middle) / kHzFrequency n3 (High) / kHz Whole blood285 7600 Blood plasma37 ± 4220 ± 101480 ± 40 Cerebral Spinal Fluid16 ± 42200 ± 140 Brain Gray Matter18,3 ± 0.3159 ± 21660 ± 20 Brain White Matter16 ± 1170 ± 102700 ± 100 Meningioma23 ±1190 ±102350 ±80 Studying the effect on the relaxation rate dispersion by heat treatment of blood plasma we found a breakpoint in the relaxation rate at 80 ºC The relaxation rate at low frequency 0.02 MHz gives an activation energy of 103 kJ/ mol above the breakpoint at 80 ºC and a very low value of 3.1±0.5 kJ/mol below 80 ºC. There seems to be no effect of Mn2+ after heating to 80 oC. This support the idea that paramagnetic ions has no effect on the firmly bound water in proteins. At room temperature, however, we found that paramagnetic ions (Mn2+) have a great influence on the relaxation rate dispersion in the low frequency region (10 - 20 kHz). Magnetic resonance relaxation dispersion imaging (MARDI) might be useful for imaging of reactive oxygen radicals and oxygen distribution by using paramagnetic or organic free-radical contrast agents. Keywords: field cycling, NMR, relaxation, dispersion, human brain, tissue, paramagnetic,
|
|
| 62. |
- Persson, Bertil R, et al.
(författare)
-
Treatment of tumour cell with 5-aza-2-deoxycytidine (DAC) for immune tumour therapy of Glioma in Fischer-344 rats
- 2012
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2012:007, s. 1-21
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Fisher 344 rats with implanted N29 glioma tumours were treated with Pulsed Electric Fields (PEF) in combination with immunization using either IFN-gamma-gene-transfected syngeneic tumour cells or IFN-gamma transfected N29 cells treated with 10 micro-M 5-aza-2-deoxycytidine (DAC). Tumours (N29) were inoculated subcutaneously on both thighs of female F- 344 syngeneic rats. The left tumour was treated once with 16 exponential pulses with an electric field strength of 1400 V/cm, and 1.0 ms duration (time constant). No anticancer drugs were given at any time. The following day and then once weekly for three weeks, the animals were given intra-peritoneal injections of irradiated, modified N29 tumour cells. The results were evaluated by daily measuring the size of tumour on both sides of the animals. Treatment with solely PEF in 32 animals resulted in a specific growth rate decrease of 20±6 % on the PEF exposed tumour. The effect at the non targeted tumour was negligible (0±4 %). Treatment with IFN-gamma secreting tumour cells resulted in a significant decrease of tumour growth rate on the right tumour of 20± 2 % (p< 0.05) and no significant effect (3±0.3% ) was observed on the left tumour. Immunization with DAC treated IFN-gamma secreting cells in 12 animals showed no significant decreased growth rate, on neither the left nor the right tumours. By combining PEF+IFN-gamma no significant decrease in growth rate was achieved. But in the combination of PEF and IFN-gamma secreting cells grown in DAC medium the tumour growth rate decreased by about 50 % at the PEF treated tumour and there was a decrease of about 20% in tumour growth at the non-PEF treated tumour rate which is about the same as for PEF treatment alone. Immune therapy of rats with intracranial N32 tumours by immunization with IFN-gamma secreting syngeneic cells treated with DAC resulted in a slight (3%) but not significant increase in survival time. With a single RT fraction of 15 Gy there was, however, a significant increase of 32% in the length of survival time of the rats with N32 tumours (p<0.02). Radiation therapy with a single fraction of 15 Gy combined with immunization with IFN-gamma secreting syngeneic cells treated with DAC resulted in significant (p<0.01) 34% increased length of survival time for the N32 tumours although there were no complete remissions.
|
|
| 63. |
- Salford, Leif, et al.
(författare)
-
GSM 900 MHz exposure of Transgenic GFAP-Mice: A study of histopathology, Tumour induction and BBB leakage
- 2012
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2012-003, s. 1-17
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Abstract. In previous work we have studied the effects of electromagnetic fields upon the promotion of growth of tumours from two different rat glioma cell lines, RG2 and N32, inoculated in the brains of Fischer 344 rats. No promotions of tumour growth due to the EMF could be demonstrated in large series of animals as compared to their matched controls. In the present study we have utilized a newly generated "knock-out" mouse model. By the use of gene targeting, Pekny et al. have created mice deficient for glial fibrillary acidic protein (GFAP), which is an astrocyte-specific protein that forms intermediate filaments in the cytoskeleton of astrocytes. The GFAP-deficient mice utilized by us develop spontaneous tumours, both lymphoblastic (non-Hodgkin) lymphomas and Anaplastic rapidly growing tumours diagnosed as malignant Swannomas. The test system consists of four TEM-cells. A GSM telephone is hooked up to a terminal program on a computer that controls the power and repetition of pulses. The rats were exposed for about 8 hours during 43 days for a total time of 1143 hours. In male GFAP-mice we found tumours in all 6 controls and in 4 out of 6 exposed. We found, however, no tumours in FM controls and in seven exposed FM mice we fund only 1 tumour. Microwave exposure revealed no significant effect on tumour evolution in the GFAP-mice. In the CBA-mice microwave exposure gave no significant results of BBB-leakage. But for the CBA-mice BBB-leakage after microwave exposure of CBA-mice was found probable at a 99% significance-level.
|
|
| 64. |
- Sun, Wenjun J., et al.
(författare)
-
Calcium efflux of plasma membrane vesicles exposed to ELF magnetic fieldsutest of a nuclear magnetic resonance interaction model
- 2012
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462. ; 33:7, s. 535-542
-
Tidskriftsartikel (refereegranskat)abstract
- The question whether very weak, low frequency magnetic fields can affect biological matter is still under debate. The theoretical possibility of such an interaction is often questioned and the site of interaction in the cell is unknown. In the present study, the influence of extremely weak 60?Hz magnetic fields on the transport of Ca2+ was studied in a biological system consisting of highly purified plasma membrane vesicles. We tested a newly proposed quantum mechanical model postulates that polarization of hydrogen nuclei can elicit a biological effect. Vesicles were exposed for half an hour at 32?degrees C and the calcium efflux was studied using radioactive 45Ca2+ as a tracer. A static magnetic field of 26?mu T and time-varying magnetic fields with a frequency of 60?Hz and amplitudes between 0.6 and 6.3?mu T were used. The predictions of the model, proposed by Lednev, that at a frequency of 60?Hz the biological effect under investigation would significantly be altered at the amplitudes of 1.3 and 3.9?mu T could not be confirmed. Bioelectromagnetics 33:535542, 2012. (c) 2012 Wiley Periodicals, Inc.
|
|
| 65. |
- Nittby, Henrietta, et al.
(författare)
-
Nonthermal GSM RF and ELF EMF effects upon rat BBB permeability
- 2011
-
Ingår i: The Environmentalist. - : Springer Science and Business Media LLC. - 0251-1088 .- 1573-2991. ; 31:2, s. 140-148
-
Tidskriftsartikel (refereegranskat)abstract
- Since the late 1980s, our group has examined the effects of radiofrequency electromagnetic fields (RF-EMF), including pulse-modulated waves of the type emitted by mobile phones, upon the blood-brain barrier. In more than 2,000 rats, we have repeatedly demonstrated a passage of the rats' own albumin from the blood through the brain capillaries into the surrounding brain parenchyma at SAR values down to 0.1mW/kg. In most of these experiments, the animals were exposed in TEM-cells, ventilated by an external electrical fan at 50 Hz. In the present study, we examined whether the extremely low frequency (ELF) magnetic fields from the fan (50 Hz, 0.3-1.5 μT) might add to the RF effect. Sixty-four rats were divided into 4 groups: RF only, ELF only and RF + ELF exposure plus a sham group. The GSM-900 MHz RF exposure was at the very low, nonthermal, average whole-body SAR level 0.4 mW/kg. Demonstration of the normally occurring albumin extravasation in the basal hypothalamus is our inbuilt control proving that the staining is reliable. Two full series of staining of the whole material gave negative results for hypothalamus. Not until we changed to avidin, biotin, and antibodies from a third supplier, we received an acceptable staining. Twenty-five percent of the RF animals had a pathological albumin leakage, while the ELF and RF + ELF groups with three and two pathological findings, respectively, were not significantly different from the control group. We conclude that the use of external fans has had no major influence upon the result.
|
|
| 66. |
- Persson, Bertil
(författare)
-
Family and School Psychosocial Environment (FSPE): Development of a brief questionnaire measuring perceived psychosocial environments in children/siblings
- 2011
-
Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 1467-9450 .- 0036-5564. ; 52, s. 303-307
-
Tidskriftsartikel (refereegranskat)abstract
- Persson, B. (2011). Family and School Psychosocial Environment (FSPE): Development of a brief questionnaire measuring perceived psychosocial environments in children/siblings. Scandinavian Journal of Psychology. The aim of the study was to develop a short Swedish standardized, factor analyzed and cross-validated, family and school psychosocial environment questionnaire (FSPE). The study was based on 244 Swedish girls and boys, 10-19 years old, who filled in the FSPE. Maximum likelihood factor analysis, promax rotation, yielded six primary factors, based on absolute ratings. Since the factors were somewhat correlated, two broader secondary factors, with satisfactory reliabilities, were also included in the form, named Warmth, support and openness from parents, siblings and peers, and Family conflicts and school discipline, respectively. Means and standard deviations for girls and boys showed sex differences in most of the factors. Because the children participated anonymously they could report about spanking without negative consequences. Indeed, 8.1% of the children had been spanked by their parents. Based on relative ratings, two factors were identified, covering environmental questions about "more than, the same as or less than" a sibling. Only 6.6% of the children rated their environment exactly the same on the Family Psychosocial Environment (FPE) factors, compared to a sibling within the family. Thus the majority reported environmental differences. Further research is proposed to evaluate such differences and relations to personality, genotype-environment correlation and genetic mediation.
|
|
| 67. |
- Persson, Bertil R, et al.
(författare)
-
“Abscopal” Effect of Radiation Therapy Combined with Immune-Therapy Using IFN-γ Gene Transfected Syngeneic Tumor Cells, in Rats with Bilateral Implanted N29 Tumors
- 2011
-
Ingår i: ISRN Immunology. - : Hindawi Limited. - 2090-5645 .- 2090-5653. ; 2011
-
Tidskriftsartikel (refereegranskat)abstract
- The tumor growth rate response was studied on N29 rat glioma tumor cells subcutaneously implanted on both hind legs of Fischer-344 rats. At around 30 days after inoculation, RT was given with 60Co gamma radiation with 4 daily fractions of 5 Gy only to the right-lateral tumors. At days 26, 42, and 54 after inoculation, immunization was performed with irradiated syngeneic IFNγ-gene transfected cells. Tumor growth rate (TGR % per day) of the right-lateral irradiated tumor was significantly decreased (P<0.01) after RT alone and with the combination of RT and immunization. But immunization alone gave no significant decrease of the TGR but significantly increased time of survival. The TGR of the unirradiated left-lateral tumors was significantly decreased (P<0.02) only in the group of rats treated with RT alone. It is apparent that tumor cells killed by the radiation mediate suppression of tumor cells outside the target area. This effect is called the abscopal effect.
|
|
| 68. |
- Persson, Bertil R, et al.
(författare)
-
Polonium-210 and lead-210 in the terrestrial environment: A historical review.
- 2011
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 102, s. 420-429
-
Tidskriftsartikel (refereegranskat)abstract
- The radionuclides (210)Po and (210)Pb widely present in the terrestrial environment are the final long-lived radionuclides in the decay of (238)U in the earth's crust. Their presence in the atmosphere is due to the decay of (222)Rn diffusing from the ground. The range of activity concentrations in ground level air for (210)Po is 0.03-0.3 Bq m(-3) and for (210)Pb 0.2-1.5 Bq m(-3). In drinking water from private wells the activity concentration of (210)Po is in the order of 7-48 mBq l(-1) and for (210)Pb around 11-40 mBq l(-1). From water works, however, the activity concentration for both (210)Po and (210)Pb is only in the order of 3 mBq l(-1). Mosses, lichens and peat have a high efficiency in capturing (210)Po and (210)Pb from atmospheric fallout and exhibit an inventory of both (210)Po and (210)Pb in the order of 0.5-5 kBq m(-2) in mosses and in lichens around 0.6 kBq m(-2). The activity concentrations in lichens lies around 250 Bq kg(-1), dry mass. Reindeer and caribou graze lichen which results in an activity concentration of (210)Po and (210)Pb of about 1-15 Bq kg(-1) in meat from these animals. The food chain lichen-reindeer or caribou, and Man constitutes a unique model for studying the uptake and retention of (210)Po and (210)Pb in humans. The effective annual dose due to (210)Po and (210)Pb in people with high consumption of reindeer/caribou meat is estimated to be around 260 and 132 μSv a(-1) respectively. In soils, (210)Po is adsorbed to clay and organic colloids and the activity concentration varies with soil type and also correlates with the amount of atmospheric precipitation. The average activity concentration levels of (210)Po in various soils are in the range of 20-240 Bq kg(-1). Plants become contaminated with radioactive nuclides both by absorption from the soil (supported Po) and by deposition of radioactive fallout on the plants directly (unsupported Po). In fresh leafy plants the level of (210)Po is particularly high as the result of the direct deposition of (222)Rn daughters from atmospheric deposition. Tobacco is a terrestrial product with high activity concentrations of (210)Po and (210)Pb. The overall average activity concentration of (210)Po is 13 ± 2 Bq kg(-1). It is rather constant over time and by geographical origin. The average median daily dietary intakes of (210)Po and (210)Pb for the adult world population was estimated to 160 mBq day(-1) and 110 mBq day(-1), corresponding to annual effective doses of 70 μSv a(-1) and 28 μSv a(-1), respectively. The dietary intakes of (210)Po and (210)Pb from vegetarian food was estimated to only 70 mBq day(-1) and 40 mBq day(-1) corresponding to annual effective doses of 30.6 μSv a(-1) and 10 μSv a(-1), respectively. Since the activity concentration of (210)Po and (210)Pb in seafood is significantly higher than in vegetarian food the effective dose to populations consuming a lot of seafood might be 5-15 fold higher.
|
|
| 69. |
- Persson, Bertil R
(författare)
-
Review article: Treating tumoral diseases (cancer) with a combination of ionizing radiation and pulsed electric fields
- 2011
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2011:001, s. 1-20
-
Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- The aim is to review a patented method and apparatus for treating tumor diseases (cancer) with a combination of ionizing radiation and pulsed electric fields, that might open a new regime of radiation therapy fractionation with a short intensive treatment with high radiation dose fractions combined with pulsed electric fields. Sub-optimal radiation treatment was administered separately or in combination with electric pulses of field strength (1200 V/cm) to subcutaneous implanted rat brain tumors on both hind legs. The treatment was repeated four consecutive days and evaluated by recording tumor growth rate and microscopically examination. Tumors were stained for Factor VIII/von Willebrand Factor to investigate effects on the tumor vasculature and for T-lymphocytes CD4 and CD8 to study their infiltration into the treated tumors. Radiation and pulsed electric fields applied concomitantly resulted in rapid tumor regression with significantly (P<0.01 vs. Control) prolonged survival (tumor free >80 days after treatment) and an average cure rate of 67%. Animals treated with either just radiation or just Pulsed electric fields showed no significant enhanced survival. Histological and immunohistochemical examination of tumors treated with RAD and PEF showed instant and severe deteriorating effects on tumor vasculature and enhanced infiltration of T-lymphocytes.
|
|
| 70. |
- Persson, Bertil R
(författare)
-
Treating tumoural diseases (cancer) with a
- 2011
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2011:001, s. 1-20
-
Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- The aim is to review a patented method and apparatus for treating tumor diseases (cancer) with a combination of ionizing radiation and pulsed electric fields that might open a new regime of radiation therapy fractionation with a short intensive treatment with high radiation dose fractions combined with pulsed electric fields. Sub-optimal radiation treatment was administered separately or in combination with electric pulses of field strength (1200 V/cm) to subcutaneous implanted rat brain tumors on both hind legs. The treatment was repeated four consecutive days and evaluated by recording tumor growth rate and microscopically examination. Tumors were stained for Factor VIII/von Willebrand Factor to investigate effects on the tumor vasculature and for T-lymphocytes CD4 and CD8 to study their infiltration into the treated tumors. Radiation and pulsed electric fields applied concomitantly resulted in rapid tumor regression with significantly (P<0.01 vs. Control) prolonged survival (tumor free >80 days after treatment) and an average cure rate of 67%. Animals treated with either just radiation or just Pulsed electric fields showed no significant enhanced survival. Histological and immunohistochemical examination of tumors treated with RAD and PEF showed instant and severe deteriorating effects on tumor vasculature and enhanced infiltration of T-lymphocytes.
|
|
