| 1. |
- Persson, Bertil R, et al.
(författare)
-
Chapter 3 Electro Dosimetry : Electro-Pulse-Enhanced-Chemo-Therapy In treatment of malignant tumours
- 2018
-
Ingår i: Electro-Pulse-Enhanced-Chemo-Therapy In treatment of malignant tumours : Chapter 3 Electro Dosimetry - Chapter 3 Electro Dosimetry. - 1651-5013. ; 2018-002
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Externa elektriska fält som appliceras på biologiska material interagerar direkt med fria elektriska laddningar som elektroner och joner samt jongrupper i större molekyler. De interagerar också med dipoler såsom vatten och inducerar dipoler i molekyler med polariserbara grupper. Cellmembranerna verkar vara det kritiska målet för interaktion som orsakar intra-molekylära övergångar och intermolekylära processer som leder till strukturell omorganisering av cellmembranen.Att tillämpa högspänningsimpulser på celler i kulturer eller i vävnad orsakar olika grader av strukturella omorganisationer i cellmembranen, vilket kan sluta med en dielektrisk kollaps eller nedbrytning. Detta tillstånd kallas antingen elektroporation eller elektropermeabilisering och kan vara reversibel eller irreversibel beroende på egenskaperna hos applicerade spänningsimpulser (Zimmermann et al., 1974).I ett sådant övergående tillstånd blir membranet permeabelt för molekyler som normalt inte passerar denna barriär in i cellens cytoplasma. Detta tillstånd kan användas för direkt överföring av gener, andra nukleinsyror, proteiner och andra molekyler till celler och mikroorganismer. En annan möjlighet är att grannceller med membran i övergående tillstånd kan smälta samman och bilda en ny jättecell. Dessa egenskaper hos membran i övergående tillstånd har lett till elektriska fältpulsteknik som ökar betydelsen i cell- och molekylärbiologi, i genteknik och i olika medicinska terapeutiska förfaranden (Neumann, 1992, Neumann et al., 1989).Användning av pulser av högspänning till celler i kulturer eller i vävnad orsakar olika grader av strukturella omorganisationer i cellmembranen, vilket kan sluta med en dielektrisk kollaps eller nedbrytning. I ett sådant övergående tillstånd ökar membranledningsförmågan Gm = 1 / Rm och membranet blir genomträngligt för molekyler som normalt inte passerar denna barriär in i cellens cytoplasma.De fysikaliska parametrar som orsakar dessa effekter är fältstyrkan hos det applicerade elektriska fältet och exponeringstidpunkten och den involverade biofysiska parametern är den elektriska ledningsförmågan hos den exponerade vävnaden. Dessa parametrar förenas i mängden specifik absorberad energi i vävnaden, vilken är den mängd som används inom joniserande strålningsområdet. På området icke-joniserande strålning används emellertid specifik absorberad effekthastighet SAR (W / kg) (Dimbylow, 1991, Garn och Gabriel, 1995). Men i Electro Enhanced Therapy är behandlingstiden viktig för resultatet och således bör den specifika absorberade energin SAE eller sW (J/kg) användas som en kvantitet elektrodosimetri.
|
|
| 2. |
- Anderson, Leif G., et al.
(författare)
-
The effect of the Siberian tundra on the environment of the shelf seas and the Arctic Ocean
- 1999
-
Ingår i: Ambio. - 0044-7447. ; 28:3, s. 270-280
-
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.
|
|
| 3. |
- Persson, Bertil R.R., et al.
(författare)
-
Effects of microwaves from GSM mobile phones on the blood-brain barrier and neurons in rat brain
- 2005
-
Ingår i: PIERS 2005 - Progress in Electromagnetics Research Symposium, Proceedings. - 1933077077 - 9781933077079 ; , s. 638-641
-
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.
|
|
| 4. |
- Belyaev, Igor Y, et al.
(författare)
-
Microwaves From UMTS/GSM Mobile Phones Induce Long-Lasting Inhibition of 53BP1/gamma-H2AX DNA Repair Foci in Human Lymphocytes
- 2009
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 30:2, s. 129-141
-
Tidskriftsartikel (refereegranskat)abstract
- We have recently described frequency-dependent effects of mobile phone microwaves (MWs) of global system for mobile communication (GSM) on human lymphocytes from persons reporting hypersensitivity to electromagnetic fields and healthy persons. Contrary to GSM, universal global telecommunications system (UMTS) mobile phones emit wide-band MW signals. Hypothetically, UMTS MWs may result in higher biological effects compared to GSM signal because of eventual "effective" frequencies within the wideband. Here, we report for the first time that UMTS MWs affect chromatin and inhibit formation of DNA double-strand breaks co-localizing 53BP1/gamma-H2AX DNA repair foci in human lymphocytes from hypersensitive and healthy persons and confirm that effects of GSM MWs depend oil carrier frequency. Remarkably, the effects of MWs on 53BP1/gamma-H2AX foci persisted up to 72 h following exposure of cells, even longer than the stress response following heat shock. The data are in line with the hypothesis that the type of signal, UMTS MWs, may have higher biological efficiency and possibly larger health risk effects compared to GSM radiation emissions. No significant differences in effects between groups of healthy and hypersensitive subjects were observed, except for the effects of UNITS MWs and GSM-915 MHz MWs on the formation of the DNA repair foci, which were different for hypersensitive (P < 0.02[53BP1)//0.01[gamma-H2AX]) but not for control subjects (P > 0.05). The non-parametric statistics used here did not indicate specificity of the differences revealed between the effects of GSM and UMTS MWs oil cells from hypersensitive subjects and more data are needed to study the nature of these differences, Bioelectromagnetics 30: 129-141, 2009. (C) 2008 Wiley-Liss, Inc.
|
|
| 5. |
- Bergqvist, Lennart, et al.
(författare)
-
Particle sizing and biokinetics of interstitiallymphoscintigraphic agents
- 1983
-
Ingår i: Seminars in Nuclear Medicine. - 0001-2998. ; 13:1, s. 9-19
-
Tidskriftsartikel (refereegranskat)abstract
- The biokinetics of inert lymphoscintigraphic agentsstrongly depends on their particle size. Different techniques for characterization of colloids are discussed. Experiments have been performed on eight different colloids. The particle size has been investigated with scanning electron microscopy. Activity distributions have been obtained with ultrafiltration and gel-column scanning technique. The colloids suggested for lymphoscintigraphy were found to have a median size of about 40-50 nm except one minimicro-aggregated human serum albumin colloid which has a median particle size around 10 nm. The biokinetics were studied with a scintillation camera in rabbits after a subcutaneous injection. Timeactivity curves were generated. After 5 hr the rabbits were dissected and the activity content in different tissues measured. A compartment model for the biokinetics was designed and rate constants evaluated. The total and specific activity uptake in parasternal lymph nodes was highest for the small-particle colloids. The compartment model showed a good fitting to the experimental data.
|
|
| 6. |
- Bolmsjö, Magnus S., et al.
(författare)
-
Imaging 123I with a scintillation camera. A study of detection performance and quality factor concepts
- 1977
-
Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155. ; 22:2, s. 266-277
-
Tidskriftsartikel (refereegranskat)abstract
- Image quality, resolution and sensitivity of a scintillation camera equipped with various collimators have been investigated using high purity 123I. Pulse height distributions of 123I from a thyroid phantom partly in air and partly immersed in water demonstrated the substantial septa penetration of the 440 and 529 keV gamma rays of 123I with high resolution collimators. Line spread functions were recorded and the modulation transfer function was evaluated from them. The two concepts of 'figure of merit' also used were QB=Sa mod MTF mod 2, where Sa is the plane sensitivity and QC=S2/(S+2B), where S is the true signal from the object and B is the total background or noise due to septa penetration and scatter.
|
|
| 7. |
- Darte, Lennart, et al.
(författare)
-
Quality control of 99mTc-radiopharmaceuticals - Evaluation of GCS minicolumns in routine clinical work with scintillation cameras
- 1980
-
Ingår i: European Journal Of Nuclear Medicine. - 0340-6997. ; 5:6, s. 521-527
-
Tidskriftsartikel (refereegranskat)abstract
- Gel chromatography column scanning (GCS) is a rapid and reliable method for the quality control of 99mTc-radiopharmaceuticals. With this method the labelled compound and various impurities such as free pertechnetate, hydrolyzed reduced technetium or other 99mTc-complexes are obtained in one testing procedure. Using minicolumns results can be obtained with a simple testing procedure within a few minutes after the sample is taken; this is significant in routine radiopharmaceutical work. The resolution of the recording system is important, so as to be able to utilize fully the good separation ability of the minicolumn. Minicolumns were studied with some commonly used radiopharmaceuticals. A scintillation camera was used to record minicolumn data under various conditions and the results were compared to those obtained using a scanner to reveal optimal recording conditions for the scintillation camera.
|
|
| 8. |
- Engström, Per E., et al.
(författare)
-
Effect of high voltage electrical pulses on subcutaneous glioma tumours on rats
- 1998
-
Ingår i: Bioelectrochemistry and Bioenergetics. - 0302-4598. ; 47:1, s. 163-166
-
Tidskriftsartikel (refereegranskat)abstract
- The antitumour effect of applied high voltage exponential pulses was investigated on rats with subcutaneously implanted N32 brain tumours. Superficial tumours on the thigh were produced by the injection of 100 000 N32 glioma cells on Fischer-344 rats. Four weeks after inoculation, a solid tumour has grown to a size of about 1 cm located directly under the skin. Short electric high voltage pulses were given transdermally through stainless steel plate electrodes. Sixteen exponential pulses with initial field strength of 1300-1400 V/cm and a time constant of 1 ms were delivered with a BTX600 device at approximately one pulse per second. The treatment was repeated during 4 consecutive days. Tumour response was studied by measuring the length, width and thickness of the tumour with a slide-calliper and estimating the tumour volume as an ellipsoid. Animals (treated and controls) were sacrificed when the size of the tumour had reached a predetermined value (5 cm3). In the first experiment this occurred after 50±4 days for the treated animals, excluding cured, compared to 40±1.3 for their controls and in the second experiment after 64±24 days excluding cured animals compared to 37.6±3 for the controls. All treated animals showed an initial partial or complete tumour remission within a few days after the end of the 4-day treatment. Two out of ten treated animals were cured with no sign of recurrence after 100 days. Copyright (C) 1998 Elsevier Science S.A.
|
|
| 9. |
- Friberg, Britt, et al.
(författare)
-
Endometrial destruction by thermal coagulation : Evaluation of a new form of treatment for menorrhagia
- 1998
-
Ingår i: Gynaecological Endoscopy. - : Wiley. - 0962-1091 .- 1365-2508. ; 7:2, s. 73-78
-
Tidskriftsartikel (refereegranskat)abstract
- Objective. To report the first clinical evaluation of a new balloon endometrial, thermal destruction system Cavaterm®, for outpatient treatment of menorrhagia. Design. To elucidate possible technical problems during treatment, to evaluate how the patients tolerated the treatment and to judge which patients were suitable for this form of treatment. Main outcome measures. Measurements of bleeding volumes in pads and tampons before and after treatment were performed as well as subjective evaluation by bleeding charts. Patients also estimated their degree of satisfaction. Setting. Gynaecology department at a university hospital. Subjects. 36 patients under 52 pears of age with menorrhagia, without suspicion of intracavitary pathology including malignancy. Results. No procedure-related complications occurred. The patients tolerated the treatment well. There was a significant reduction in measured bleeding volumes in pads and tampons, collected during one menstruation, 2-7 months after treatment compared with measurements before treatment. Four patients subsequently underwent hysterectomy and should not have been included in the study (two with pedunculated myoma and one with a septum; the fourth showed premalignant endometrial changes in the curettage preceding the treatment). At 18-28-month follow up, 29 of the suitable patients (91%) reported a significant reduction in bleeding and another three patients reported reduced but still profuse bleeding compared with pretreatment; 88% (28/32) rated the treatment results as excellent, and a further 9% (3/32) as good. Conclusions. We found the Cavaterm® system for endometrial destruction to be safe, efficient and easy to use.
|
|
| 10. |
- Henricsson, Fredrik, et al.
(författare)
-
Polonium-210 in the bio-sphere : Bio-kinetics and biological effects
- 2012
-
Ingår i: Radionuclides : Sources, Properties and Hazards - Sources, Properties and Hazards. - 9781619427488 ; , s. 33-60
-
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.
|
|
