| 1. |
- Persson, Bertil R, et al.
(författare)
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Radioactivity Exploration from the Arctic to the Antarctic. Part 1: Introduction
- 2015
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Ingår i: Radioactivity Exploration from the Arctic to the Antarctic.. - 1651-5013. ; 2015-002, s. 1-4
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Bokkapitel (refereegranskat)abstract
- This book is dedicated to professor emeritus Bengt Forkman (Nuclear Physics, Lund University) who in 1979 took the initiative to arrange an environmental radioactivity research program for the Ymer-80 expedition. He engaged his old friend Bertil Persson whom he during the 1960th inspired to university studies in Lund who just been promoted to professor of Radioecology at the Swedish University of Agricultural Sciences in Uppsala. Bertil Persson was tutor for Elis Holm at Lund University, who for his thesis was engaged in radiochemical analysis of plutonium isotopes in the environment. Elis Holm became deeply involved in management of Ymer-80 and all the following expeditions as well. We found a superior talent for the logistics in Kjell-Åke Carlsson (who was mechanical engineer at the department of radiation physics at Lund University). Without him, we would not have been able to solve all the thousands of practical issues and contacts with authorities and sponsors. He also contributed with the diaries extensive photographic and video documentation of all the expeditions. We have together compiled this book although several others were partly engaged in the various expeditions to whom we are deeply thankful for their contributions. They will appear as contributors in the separate parts of this book: 1. Ymer-80 (Bengt Forkman, Boel Forkman, Lars Ahlgren (diseased) 2. Swedarp 1988-1989 (Per Roos, Birgitta Roos) 3. Arctic Ocean 1991 4. Tundra Expedition 5. Arctic Ocean 1996 (Dan Josefsson, Mats Ericsson)
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| 2. |
- Persson, Bertil R.R., et al.
(författare)
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Effects of microwaves from GSM mobile phones on the blood-brain barrier and neurons in rat brain
- 2005
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Ingår i: PIERS 2005 - Progress in Electromagnetics Research Symposium, Proceedings. - 1933077077 - 9781933077079 ; , s. 638-641
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Konferensbidrag (refereegranskat)abstract
- Our group has since 1988 studied the effects of different intensities and modulations of 915MHz RF in a rat model where the exposure takes place in a TEM-cell during various time periods and post exposure recovery times. The power fed into TEM-cells was 0.125, 1.25, 12.5 or 125mW corresponding to whole body SAR (determined experimentally): 0.2, 2, 20 or 200mW/kg. The rats were awake and not restrained during exposure and after the recovery period the animals were anaesthetized and sacrificed by perfusion-fixation with 4% formaldehyde. Paraffin embedded 5 μm. thick brain slices were stained for albumin by applying albumin antibodies (Dakopatts), by which albumin is revealed as brownish discolorations. Dark neurons were revealed by staining for RNA/DNA with cresyl violet. In series of more than 1800 Fisher rats, we have proven that sub thermal power levels from both pulse-modulated and continuous RF fields - including those from real GSM mobile phones - have the potency to significantly open the BBB for the animals' own albumin (but not fibrinogen) to pass out into the brain and to accumulate in the neurons and glial cells surrounding the capillaries. Albumin extravasations are most prominent at the lower SAR values. This dose-response behaviour suggests some kind of energy or electromagnetic field strength windowing effect. A linear dose-response relationship for dark neurons was found at 50 days after exposure, with most prominent occurrence at SAR 200mW/kg.
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| 3. |
- Anderson, Leif G., et al.
(författare)
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The effect of the Siberian tundra on the environment of the shelf seas and the Arctic Ocean
- 1999
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Ingår i: Ambio. - 0044-7447. ; 28:3, s. 270-280
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Tidskriftsartikel (refereegranskat)abstract
- The Tundra Ecology -94 expedition investigated inflow of inorganic and organic carbon to the shelf seas by river runoff, and its transformation by biochemical processes in seawater and sediment. In addition, anthropogenic radionuclides, 137Cs, 90Sr, and 239,240Pu, were studied in water and sediments. The distribution of dissolved inorganic carbon indicates that the majority of the Ob and Yenisey discharges flow into the Laptev Sea before entering the central Arctic Ocean. The sediment study shows that there is a marked difference in benthic oxygen uptake, efflux of dissolved inorganic carbon and nutrients between localities. 137Cs activity from the Chernobyl accident is 30% in the Barents, Kara, and Laptev Seas. 137Cs increased from 5-8 Bq m-3 in Barents Sea, 5-13 Bq m-3 in the Kara Sea to 8-15 Bq m-3 in the Laptev Sea, but with locally low concentrations at the river mouths. Corresponding values for 90Sr were 2.5, 3, and 4 Bq m-3, respectively.
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| 4. |
- Capala, J, et al.
(författare)
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Boron neutron capture therapy for glioblastoma multiforme : Clinical studies in Sweden
- 2003
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Ingår i: Journal of Neuro-Oncology. - 1573-7373. ; 62:1, s. 135-144
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Tidskriftsartikel (refereegranskat)abstract
- A boron neutron capture therapy (BNCT) facility has been constructed at Studsvik, Sweden. It includes two filter/moderator configurations. One of the resulting neutron beams has been optimized for clinical irradiations with a filter/moderator system that allows easy variation of the neutron spectrum from the thermal to the epithermal energy range. The other beam has been designed to produce a large uniform field of thermal neutrons for radio-biological research. Scientific operations of the Studsvik BNCT project are overseen by the Scientific Advisory Board comprised of representatives of major universities in Sweden. Furthermore, special task groups for clinical and preclinical studies have been formed to facilitate collaboration with academia. The clinical Phase II trials for glioblastoma are sponsored by the Swedish National Neuro-Oncology Group and, presently, involve a protocol for BNCT treatment of glioblastoma patients who have not received any therapy other than surgery. In this protocol, p-boronophenylalanine (BPA), administered as a 6-h intravenous infusion, is used as the boron delivery agent. As of January 2002, 17 patients were treated. The 6-h infusion of 900 mg BPA/kg body weight was shown to be safe and resulted in the average blood-boron concentration of 24 μg/g (range: 15-32 μg/g) at the time of irradiation (approximately 2-3 h post-infusion). Peak and average weighted radiation doses to the brain were in the ranges of 8.0-15.5 Gy(W) and 3.3-6.1 Gy(W), respectively. So far, no severe BNCT-related acute toxicities have been observed. Due to the short follow-up time, it is too early to evaluate the efficacy of these studies.
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| 5. |
- Ceberg, Crister, et al.
(författare)
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A stochastic model for subcellular dosimetry in boron neutron capture therapy
- 1995
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 40:11, s. 1819-1830
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Tidskriftsartikel (refereegranskat)abstract
- The therapeutic effectiveness of boron neutron capture therapy is highly dependent on the microscopic distribution of the administered boron compound. Two boron compounds with different uptake mechanisms in the tumour cells may thus cause effects of different degrees even if the macroscopic boron concentrations in the tumour tissue are the same. This difference is normally expressed quantitatively by the so-called relative local efficiency (RLE). In this work, a stochastic model for the subcellular dosimetry has been developed. This model can be used to calculate the probability for an energy deposition above a certain threshold level in the cell nucleus due to a single neutron capture reaction. If a threshold cell-kill function is assumed, and if the dose is low enough that multiple energy depositions are rare, the model can also be applied to calculations of the survival probability for a cell population. Subcellular boron distributions in rats carrying RG 2 rat gliomas were measured by subcellular fractionation after administration of two different boron compounds: a sulphydryl boron hydride (BSH) and a boronated porphyrin (BOPP). Based on these data, the RLE factors were then calculated for these compounds using the stochastic model.
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| 6. |
- Ceberg, Crister, et al.
(författare)
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Performance of sulfhydryl boron hydride in patients with grade III and IV astrocytoma: a basis for boron neutron capture therapy
- 1995
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Ingår i: Journal of Neurosurgery. - 0022-3085. ; 83:1, s. 79-85
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the rationale of boron neutron capture therapy (BNCT) for the treatment of Grade III and IV astrocytoma. The European Community joint research program on BNCT plans to use sulfhydryl boron hydride (BSH) in clinical trials. The work presented here, examines the performance of BSH in eight patients with Grade III and IV astrocytoma using a measurement technique which precisely correlates the boron uptake with the histology of the tumor and the peritumoral brain. Astrocytomas are exceptionally heterogeneous and spread migrating tumor cells into the surrounding brain. The patients were infused with 50 mg BSH per kilogram of body weight at 12, 18, 24 or 48 hours before surgery. At the time of operation, specimens were obtained of the tumor, skin, muscle, dura, blood, urine, and, when surgically possible, the brain adjacent to tumor. In three patients the intracellular boron distribution was investigated by subcellular fractionation. The blood clearance was biphasic with half-lives of 0.6 and 8.2 hours. After 3 days, approximately 70% of the dose injected was excreted in the urine. The maximum boron concentration in the tumor was 20 ppm, 12 hours after the infusion. The tumor-to-blood ratios ranged between 0.2 and 1.4, with the highest values after 18 to 24 hours. In the brain specimens the boron concentration never exceeded 1 ppm. This work confirms a selective uptake of boron in the tumor compared to the surrounding brain and that boron, to some extent, is incorporated in the tumor cells.
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| 7. |
- Glahder, J, et al.
(författare)
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Transfection of HeLa-cells with pEGFP plasmid power-assisted by impedance electroporation
- 2005
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 1097-0290 .- 0006-3592. ; 92:3, s. 267-276
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Tidskriftsartikel (refereegranskat)abstract
- Bioimpedance spectrometry was applied to study cell viability and pEGFP plasmid-transfection efficiency in electroporation (EP) of 20,000 HeLa cells with 0.3 mu g DNA in 90 mu l low conductivity 0.32 M sucrose medium of pH 7.5. Monopolar rectangular pulses, of field strength 75 V/mm, and pulse length 0.1 ms were applied in 1-16 repetitions with a 10-sec pause interval between pulses. Surviving cells were stained by crystal violet and counted using a confocal microscope. Transfected cells were fixed with 10% formaldehyde and counted as green spots in a fluorescence microscope. In the present investigation we used the method of bioimpedance spectrometry to analyze the effect of EP on survival and transfection ratio of cells in suspension. DC and low-frequency AC currents preferably pass through the medium due to the high impedance of the cell membrane. At frequencies above 10 kHz the impedance of the cell membrane starts to decrease and the impedance value of the cell suspension approach a lower limit value R-infinity at infinite frequency. Recording of electrical impedance spectra of cells in culture was performed over a frequency range of 10 Hz to 125 kHz, allowing separation of the contribution from extracellular space and that of the cell membranes. A parallel resistance capacitance model of the cell suspension was used to evaluate the response of applying EP pulses. The values of the collective membrane resistance R-M decay exponentially (r(2) = 0.995) with the number of applied pulses. The ratio of the extrapolated value of the intact membrane resistance before pulsing, R-M,(O), and the value R-M,R-N after each pulse makes an index of the effect of electroporation on the cells. The ratio R-M,R-N/R-M,(O) as well as the relative change of the dissipation factor, tan delta, on the "Loss Change Index" (LCI) fits well a dose-response model (r(2) = 0.98) with the number of applied pulses. The changes in the model parameters membrane resistance Delta R-M = [1- R-M,(N)/R-M,o] and loss factor [1- tan delta(O)/tan Omega(N)] correlate well with the transfection ratio and fraction of dead cells. Those parameters were used for power-assisted electroporation in monitoring, controlling, and optimizing the EP procedure.
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| 8. |
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| 9. |
- Widell, Anders, et al.
(författare)
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Epidemiologic and molecular investigation of outbreaks of hepatitis C virus infection on a pediatric oncology service
- 1999
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Ingår i: Annals of Internal Medicine. - : American College of Physicians. - 0003-4819. ; 130:2, s. 130-134
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Despite screening of blood donors, hepatitis C virus (HCV) infection can occur in patients who receive multiple transfusions. OBJECTIVE: To clarify mechanisms of nosocomial transmission of HCV. DESIGN: Epidemiologic and molecular analyses of hepatitis C outbreaks. SETTING: Pediatric oncology ward. PATIENTS: Children with cancer. MEASUREMENTS: Epidemiologic analysis, HCV RNA detection, genotyping, and hypervariable region 1 (HVR1) sequencing. RESULTS: Ten cases of infection with acute HCV genotype 3a occurred between 1990 and 1993. Sequencing of HVR1 revealed three related strains. Despite an overhaul of hygiene procedures, a patient infected with genotype 1b generated nine subsequent infected patients in 1994. Several patients had high virus titers and strongly delayed anti-HCV antibody responses. All had permanent intravenous catheters. Multidose vials used for flushing or treatment had probably been contaminated during periods of overlapping treatment. CONCLUSIONS: Contamination of multidose vials was the most likely mode of HCV transmission; therefore, use of such vials should be restricted. Rigorous adherence to hygiene routines remains essential to preventing transmission of bloodborne infections.
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| 10. |
- Persson, Bertil
(författare)
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Family and School Psychosocial Environment (FSPE): Development of a brief questionnaire measuring perceived psychosocial environments in children/siblings
- 2011
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Ingår i: Scandinavian Journal of Psychology. - : Wiley. - 1467-9450 .- 0036-5564. ; 52, s. 303-307
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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.
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