| 1. |
- Persson, Bertil R, et al.
(författare)
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Chapter 3 Electro Dosimetry : Electro-Pulse-Enhanced-Chemo-Therapy In treatment of malignant tumours
- 2018
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Ingår i: Electro-Pulse-Enhanced-Chemo-Therapy In treatment of malignant tumours : Chapter 3 Electro Dosimetry - Chapter 3 Electro Dosimetry. - 1651-5013. ; 2018-002
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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.
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| 2. |
- Persson, Bertil R, et al.
(författare)
-
Clinical Studies of EpECT with Bleomycin or Cis-Platin
- 2018
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Ingår i: Electro-Pulse-Enhanced-Chemo-Therapy. - 1651-5013. ; 2018, s. 1-1
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In recent years several authors have reviewed the clinical results of Electro Enhanced Chemotherapy: • Electro-chemotherapy for primary skin cancer and skin metastasis related to other malignancies (Reinhold, 2011). • Utility of electro-chemotherapy in melanoma treatment (Testori et al., 2012).• Antitumor effectiveness of electro-chemotherapy: A systematic review and meta-analysis (Mali et al., 2013).• Electro-chemotherapy in Breast Cancer: A Review of References (Schmidt et al., 2014).• Treatments of advanced basal cell carcinoma: a review of the literature" (Peris et al., 2016).• Treatment efficacy with electro-chemotherapy: A multi-institutional prospective observational study on 376 patients with superficial tumours"(Campana et al., 2016b).• Basal cell carcinoma: 10-year experience with electro-chemotherapy (Campana et al., 2017b).• Electro-chemotherapy in Breast Cancer - Discussion of the Method and Literature Review (Wichtowski et al., 2017). The treatment results are in most cases reported in terms of following quantities where the fractional response = (No. cases with the actual response / Total No. Cases) CR = Complete response; PR = partial response; SD = stable disease; PD = progressive disease; OR = objective response; CR = fractional complete response; PR = fractional partial response; SD = fractional stable disease; PD = fractional progressive disease; OR = fractional objective responseUsually the sum of complete and partial responses called Objective Response (OR = CR + PR) is used as a general quantity for the response of the treatment in question without considering the responses of stable and progress disease.In order to be able unify all four quantities into a quantity which consider the total response a quantity named “fractional weighting response”, WR is defined as follow:In order to estimate the response considering all four response quantities a quantity named “fractional weighted response”, WR is defined as follow:WR = (3OR + 1PR + 0SD - 3PR)/3;The following sections summarize the published responses of clinical electro-chemotherapy for each specific type of tumour, and estimate the fractional weighting response from the data of each published report.
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| 3. |
- Persson, Bertil R, et al.
(författare)
-
PSI-PSYCHO SCHIZOFRENI IMAGING : Hjärnavbildning vid Schizofreni. Del 2. Hjärnavbildning med radioaktiva spårämnen
- 2022
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2022-002, s. 0-39
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Denna andra delen av Hjärnavbildning vid Schizofreni beskriver användningen av radioaktiva ämnen som startade i Lund med professor David Ingvars pionjär studier av att avbilda cerebralt blodflöde med Xenon-133 hos patienter med Schizofreni. De nukelar medicinska metoderna utvecklades till Single Photon Emission Computed Tomography, SPECT, använder gammastrålning som emitteras direkt från internt distribuerade radiofarmaka i patienten som detekteras av en enda eller en uppsättning kollimerade strålnings-detektorer eller gammakameror. Nya radiofarmaka utvecklades såsom 99mTc-HMPAO d.v.s. 99mTc-Hexa-Methyl-Propylen-Amine-Oxim kräver ingen flödesstudie utan visar hur perfusionsmönstret såg ut vid tidpunkten för injektionen. Cerebral SPECT och 99mTc-HMPAO kan användas för att skilja mellan patienter som diagnostiserats med Schizofreni och friska kontrollpersoner. Även dopaminhypotesen som förklaringsmodell till Schizofreni har sitt ursprung i Lund med Arvid Carlssons upptäckt (Carlsson and Lindqvist, 1963). Med hjärnavbildnings-tekniken Positron-Emissions-Tomografi(PET) blev det möjligt att studera receptorbindning direkt i den levande mänskliga hjärnan. PET studier av frisättning och transport av dopamin, samt bindning av dopamin till Dopaminreceptorn D2R, visar att schizofrena patienter har en ökad tillgänglighet av dopamin i den striato-thalamo-kortikala transportvägen vägen och en minskad tillgänglighet i den mesolimbocortical vägen. Under 1980 talet visade det sig att regionalt blodflöde och metabolism med användningen av PET med 18F-fluordeoxyglucos (18FDG) var ett kraftfullt verktyg i psykiatrisk forskning om Schizofreni Under 1990 talet ökade omfattningen av 19FDG-PET studier på patienter med Schizofreni som ofta resulterar i dysfunktionella avvikelser vilka indikerar störd kommunikation i hjärnans kretslopp snarare än fokala skador i hjärnan. Hos patienter med Schizofreni visar 19FDG-PET studier förändringar främst i prefrontala, striatala, talamiska och temporala strukturer.
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| 4. |
- Persson, Bertil R, et al.
(författare)
-
PSI-PSYCHO SCHIZOFRENI IMAGING-Ψ : Hjärnavbildning vid Schizofreni. Del 1
- 2022
-
Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2022-001, s. 0-9
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Med hjälp av mina medarbetare vid institutionen för Radiofysik på universitetet och avdelningen för sjukhusfysik vid lasarettet började vi 1981 bygga Skandinaviens första bildgivande NMR scanner. För att sprida kunskap om medicinska tillämpningar av NMR arrangerade Svensk förening för radiofysik på hösten 1981 en föreläsningsserie med både läkare, fysiker och ingenjörer på seminstationen i Hörby. Föreläsnings anteckningar sammanfattades i den första läroboken i ämnet med en NMR-bild av mitt hjärta på omslaget (Persson, 1982). Jag närde en hypotes om att själen skulle kunna avspeglas med vattnets struktur i hjärnan vilket NMR-relaxationen av protonerna skulle kunna avslöja. Därmed skulle bildgivande kärnspinnresonans kanske kunna avbilda själen, som jag tyckte borde finnas där någonstans inom oss. Men det blev mest en skröna som mina medarbetare skojade om.När min första MR-doktor, Freddy Ståhlberg ordnade så att det år 2015 kom en nationell MR-forskningsresurs i form av en 7-tesla magnet till Lund, då ställdes 0,07 tesla prototypen till Lunds första NMR scanner som relik i entrén (Persson and Ståhlberg, 2017). Med en 7 tesla magnet öppnas möjligheten att studera NMR spektrum i tillräckligt hög upplösning för att icke-invasivt identifiera ett flertal kemiska substanser i hjärnan. Dessa substanser reglerar våra kognitiva funktioner och jag kände att här öppnar sig kanske en möjlighet att studera ”Själens kemi”. Detta är bakgrunden till denna serie om Hjärnavbildning vid Schizofreni som jag tillägnar någon som fått denna diagnos.Denna första del beskriver ”Hur det blev ”. Förkortningen av ”Psycho Schizofreni Imaging” PSI associerar till den grekiska bokstaven ( som i kvantfysiken betecknar tillståndsvektorn eller vågfunktionen som innehåller informationen om det system den beskriver. Den mänskliga hjärnan tycks ursprungligen vara skapt för att använda en kvantliknande logik som schizofrena patienter tycks förlita sig på. Denna kvant-neuro-biologiska syn på schizofreni är fortfarande i sin linda, och detta spekulativa kvantfysiska synsätt återkommer jag till i fortsättningen på ”Psycho Schizofreni Imaging”.
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| 5. |
- Persson, Bertil R, et al.
(författare)
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PSI-PSYCHO SCHIZOPHRENIA IMAGING : Hjärnavbildning vid Schizofreni. Del 3. Magnetisk resonans och schizofreni
- 2022
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Ingår i: Acta Scientiarum Lundensia. - 1651-5013. ; 2022, s. 0-61
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Denna tredje del av Hjärnavbildning vid Schizofreni sammanfattar olika metoder med magnet spinn resonans (MR) applicerade på Schizofreni patienter 1. Introduktion till MR2. Struktur-magnet resonans imaging sMRI3. MR-CSF cerebralt blodflödes imaging4. Funktionell-magnet resonans imaging MRI5. Diffusion Tensor Imaging DTI6. Magnetisk transfer Imaging MTI7. Magnet resonans spektrometri MRS8. Kombinerade metoderSture Forsén och Ragnar Hoffman presenterade år 1963 en magnetisk dubbel-resonans-metod tillämpbar på system där ett kärnspinn reversibelt överförs mellan två icke-ekvivalenta molekyler, från A till B, vilket utnyttjas i ” Magnetisk transfer Imaging MTI” (kap 3.6) (Forsen and Hoffman, 1963). Det kan vara värt att nämna att Sture Forsén är professor emeritus i fysikalisk kemi vid Lunds Universitet. Beskrivningen av utvecklingen inom de olika områdena av MR har emellertid blivit så omfattande att min ambition att beskriva den detaljerade historiska utvecklingen av de olika MR-metoderna kommer att preseteras efter hand . Därför kommer i del III endast som en sammanfattning av MR och Schizofreni. Struktur-magnet resonans imaging sMRI visar att förändrad gyrifiering verkar vara en signifikant robust markör för störningar i den tidiga neuronala utvecklingen vid Schizofreni. Ökningar av gyrifiering observerades i bilaterala insula, temporala polen och vänster orbitofrontal cortex.Även tjockleken av de frontala loberna återspeglar en patologisk process vid Schizofreni med minskad kortikal tjocklek i prefrontala cortex, precuneus och occipital cortex.Utvärdering av CSF flödesdynamik i akvedukten tillsammans med volymetriska sMRI undersökningar av hjärnan skulle ytterligare kunna förstärka kunskapen kring patofysiologin både i samband med diagnostik och behandlings uppföljning av patienter med Schizofreni. Ett flertal studier indikerar att patienter med Schizofreni har lägre MRI aktivitet i den dorsolaterala, prefrontala cortex(PFC), accumbenskärnan(ACC) och i thalamus mediodorsala kärnan. Däremot observeras ökning av aktiviteten inom andra PFC-områden, vilka skulle kunna vara kompenserande till sin natur.Resultaten tyder på att MRI-baserad klassificering återspeglar förändringar i diskreta neurala kretsar och kan vara ett användbart verktyg för att definiera undergrupper inom det kliniskt definierade syndromet Schizofreni. Dock finns ännu ingen konsensus om vilken (MRI metod som är bäst lämpad för klinisk användning. DTI studier av schizofrena patienterna visar lägre FA-värden än friska kontroller. FA-värdet för den främre delen av corpus callosum är negativt korrelerat med poängen på skalan för bedömning av negativa symtom . Lägre FA-värden i vänster och bilaterala superior longitudinella fasciculi (SLF) hos schizofrena patienterna än friska kontroller verkar vara specifika för Schizofreni med hörselhallucinationer(AVH). En negativ korrelation registrerades mellan genomsnittlig regional FA i höger anterior cingulum och PANSS-positiv symptompoäng. Den stora betydelsen av MTI är resultaten av dess kombination med DTI som visar sig kunna indikera högre extracellulära koncentrationer av fritt vatten, vilket indikerar förekomsten av neuroinflammation vid Schizofreni. 1H-MRS och Schizofreni visar signifikanta skillnader mellan kaudal och rostral NAA-koncentration i den del av de basala ganglierna som kallas accumbens ACC, hos patienter med Schizofreni men inte hos friska kontrollpersoner. Denna skillnad indikerar att neuronal densitet eller integritetsskillnader mellan ACC-subregioner kan vara karakteristiska för Schizofreni. Resultaten visar också att NAA-koncentrationerna är lägre i frontallob och talamus hos patienter med första episod psykos jämfört med kontroller vilket indikerar att Schizofreni är associerad med lägre neural metabolisk aktivitet. Resultaten av 1H-MRS studier tyder på att kolin ökar i både prefrontala och occipitala cortex under nyligen debuterade Schizofreni vilket indikerar tecken på neuroinflammation.
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| 6. |
- Persson, Bertil R, et al.
(författare)
-
PSI-PSYCHO SCHIZOPHRENIA IMAGING- Hjärnavbildning vid Schizofreni. : Del 4: Ämnesomsättning och Schizofreni
- 2023
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Ingår i: Acta Scientiarum Lundensia. ; 2023-001, s. 1-112
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- 4-5.1 Sammanfattning av Glutamat och GABA vid Schizofreni1H-MRS och kronisk schizofreni1H-MRS visar att alla Schizofreni patienter hade ett signifikant lägre N-AcetylAsparagin-syra(NAA) till Kreatin(Cr) nivåförhållande i frontalloben än kontrollerna. Resultaten indikerar att det finns ett samband mellan det Glutamat-erga systemet och patofysiologin vid Schizofreni. (Szulc et al., 2013).GABA och glutamat vid schizofreni Signifikant lägre GABA till Kreatin(Cr)-nivåkvoter observerades i den prefrontala cortex hos patienter med Schizofreni jämfört med friska kontroller. Lägre GABA-nivåer men oförändrade glutamatnivåer i den mediala prefrontala cortexen vid Schizofreni, observerades särskilt hos högpresterande patienter. (Marsman et al., 2014).1H-MRS och Glutamat koncentrationer Resultaten av MRS visar att signifikant lägre Glutamat koncentrationer i Hippocampus vid Schizofreni är associerat med patofysiologin för Schizofreni, (Stan et al., 2015).4-5.2 Sammanfattning Tryptofan katabolism och SchizofreniAktivering av Tryptofanmetabolismen (TRYCAT)-vägen tycks vara involverad i patofysiologin för Schizofreni. Patienter med Schizofreni rapporterades ha signifikant lägre serum-nivåer av Kynurensyra(KYNA) som dämpar effekten av α-7nikotin-acetyl-kolin receptorn (α7nAChR) och/eller N-metyl-D-Aspartatreceptorn (NMDAR), två av de receptortyper vars dysfunktion tros bidra till kognitiv försämring vid Schizofreni. (Huang et al., 2021)}.CSF-nivåer av Kynurensyra är förhöjda vid Schizofreni, vilket motiverar till nya terapeutiska strategier inriktade på hjärnans Kynurensyrasyntes. Studier i djurmodeller indikerar att höga nivåer av Tryptofan undertrycker aggressivt beteende, troligtvis relaterat till ökad central Serotonin tillgänglighet (Erhardt et al., 2001). Andra resultat visar att potentialen för bildning av antioxidant Urinsyra(UA) från purinkatabolismen förändras tidigt under sjukdomsförloppet (Yao et al., 2010b). Zhou visade att det finns ett negativt samband mellan volymen av grå substans(GMV) och förhållandet mellan plasmanivåerna av Kynurenin och Tryptofan (KYN/TRP och KYN) vid Schizofreni (Zhou et al., 2022).En signifikant ökning av Kynurenin till Tryptofan förhållandet observerades i CNS och med en måttlig ökning av serum-IDO-aktivitet. (Almulla et al., 2022).Patienter med Schizofreni visar jämfört med friska kontroller signifikanta skillnader för Tryptofan metaboliter i CNS vilket slutligen kan påverka glutamat-ergisk neurotransmission via N-metyl-D-aspartat och α-7Nikotin receptorer (Sales et al., 2023).Godin rekomonderade att följande åtgärder för prevention av metabolism Syndrom(MetS) och forskning inom Schizofreni som bör främjas i klinisk praxis (Godin et al., 2023): •främjande av tobaksavvänjning, •undvikande av antidepressiva medel med risk för ökad Mets och •främjande av fysisk aktivitet bör främjas mer aktivt. •tidig förskrivning av Omega 3-fettsyror och•viktminskningsmediciner (metformin och topiramat), •specifika metabola läkemedel (statin och fenofibrat), •kirurgisk minskning av fettvävnad och •mikrobiota-orienterade behandlingar. Studier av vuxna och barn med impulsivt och/eller våldsamt beteende visar indikationer på att: • Impulsivt och våldsamt beteende är förknippat med förändrad Serotonin metabolism. • Tarm-mikrobiomet kan kontrollera värdens tryptofanmetabolism. • Tarm- mikrobiomet spelar en roll i våldsamt beteende. (Langmajerová et al., 2023). En systematisk genomgång av neuroimaging studier av Kynurenin-vägen visar robusta indikationer på att cerebrala abnormiteter är associerade med Kynurenin.vägen (Wang et al., 2023). 4-5.3 Sammanfattning av andra metaboliter vid Schizofreni Nuvarande diagnostiska metoder för Schizofreni bygger på psykiatriska intervjuer, vilka är subjektiva till sin natur. Dock finns det indikationer på att följande metabolitmarkörer skulle kunna främja Schizofreni-diagnos och behandlings uppföljning:Citrat, Palmitinsyra, Myo-inositol och Allantoin vid Schizofreni.Utav tjugotvå studerade markörmetaboliter visade sig Citrat, Palmitinsyra, Myo-inositol och Allantoin uppvisa den bästa förmågan att fullständigt separera Schizofrena patienter från matchade friska kontroller och kan vara användbara biomarkörer för att övervaka terapeutisk effekt (Cai et al., 2012).Yang och medarbetare rapporterade år 2013 resultaten från en global metabolisk profileringsstudie som identifierade en panel av serum-markörer identifierades bestående av: •Glycerat, •Eikosensyra, •β-hydroxibutyrat, •Pyruvat och •Cystin En mer sammansatt panel uppnåddes genom att till serumpanelen tillföra•β-hydroxybutyrat i urinMed denna sammansatta panel uppnåddes en separerbarhet på 100% i både tränings- och test-setet, vilket innebär en säkerhet i Schizofreni diagnos som motsvarar kliniska intervjuer (Yang et al., 2013). Metabolisk analys av Schizofreni patienter efter Risperidon terapi.Myo-inositol, Urinsyra och Tryptofan i plasma skilde sig före och efter Risperidon behandling av patienter med Schizofreni. Metaboliska vägar inklusive energimetabolism, antioxidantförsvarssystem, neuro-transmittor metabolism, fettsyrabiosyntes och fosfolipid metabolism visade sig vara störda hos Schizofrena patienter men normaliserades delvis efter Risperidon behandling (Xuan et al., 2011).
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| 7. |
- 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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| 8. |
- 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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| 9. |
- 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
-
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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| 10. |
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| 11. |
- Capala, Jacek, et al.
(författare)
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Clinical BNCT studies in Sweden
- 2002
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Ingår i: Research and development in neutron capture therapy. - : Monduzzi Editore Print. ; , s. 1101-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 12. |
- Ceberg, Crister, et al.
(författare)
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A stochastic model for subcellular dosimetry in boron neutron capture therapy
- 1995
-
Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 1361-6560 .- 0031-9155. ; 40:11, s. 1819-1830
-
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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| 13. |
- Ceberg, Crister, et al.
(författare)
-
Performance of sulfhydryl boron hydride in patients with grade III and IV astrocytoma: a basis for boron neutron capture therapy
- 1995
-
Ingår i: Journal of Neurosurgery. - 0022-3085. ; 83:1, s. 79-85
-
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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| 14. |
- 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
-
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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| 15. |
- Lai, En Yin, et al.
(författare)
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Contribution of adenosine receptors in the control of arteriolar tone and adenosine-angiotensin II interaction
- 2006
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Ingår i: Kidney International. - : Elsevier BV. - 0085-2538 .- 1523-1755. ; 70:4, s. 690-698
-
Tidskriftsartikel (refereegranskat)abstract
- Adenosine (Ado) mediates vasoconstriction via A(1)-Ado receptors and vasodilation via A(2)-Ado receptors in the kidney. It interacts with angiotensin II (Ang II), which is important for renal hemodynamics and tubuloglomerular feedback (TGF). The aim was to investigate the function of Ado receptors in the Ado -Ang II interaction in mouse microperfused, afferent arterioles. Ado (10(-11)-10(-4) mol/l) caused a biphasic response: arteriolar diameters were reduced (-7%) at Ado 10(-11)-10(-9) mol/l and returned to control values at higher concentrations. Treatment with Ang II (10(-10) mol/l) transformed the response into a concentration-dependent constriction. N-6-cyclopentyladenosine (A(1)-Ado receptor agonist) reduced diameters (12% at 10(-6) mol/l). Application of CGS21680 (10(-12)-10(-4) mol/l, A(2A) receptor agonist) increased the diameter by 13%. Pretreatment with ZM241385 (A(2A)-Ado receptor antagonist) alone or in combination with MRS1706 (A(2B)-Ado receptor antagonist) resulted in a pure constriction upon Ado, whereas 8-cyclopentyltheophylline (CPT) (A(1)-Ado receptor antagonist) inhibited the constrictor response. Afferent arterioles of mice lacking A(1)-Ado receptor did not show constriction upon Ado. Treatment with Ado (10(-8) mol/l) increased the response upon Ang II, which was blocked by CPT. Ado (10(-5) mol/l) did not influence the Ang II response, but an additional blockade of A(2)-Ado receptors enhanced it. The action of Ado on constrictor A(1)-Ado receptors and dilatory A(2)-Ado receptors modulates the interaction with Ang II. Both directions of Ado-Ang II interaction, which predominantly leads to an amplification of the contractile response, are important for the operation of the TGF.
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| 16. |
- 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
-
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.
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| 17. |
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| 18. |
- 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
-
Ingår i: Annals of Internal Medicine. - : American College of Physicians. - 0003-4819. ; 130:2, s. 130-134
-
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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| 19. |
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| 20. |
- Al-Qaradawi, Ilham, et al.
(författare)
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Radioactivity levels in the marine environment along the Exclusive Economic Zone (EEZ) of Qatar.
- 2015
-
Ingår i: Marine Pollution Bulletin. - : Elsevier BV. - 1879-3363 .- 0025-326X. ; 90:1-2, s. 323-329
-
Tidskriftsartikel (refereegranskat)abstract
- A study on (137)Cs, (40)K, (226)Ra, (228)Ra, and (238)U was carried out along the EEZ of Qatar. Results serve as the first ever baseline data. The level of (137)Cs (mean value 1.6±0.4Bqm(-3)) in water filters was found to be in the same order of magnitude as reported by others in worldwide marine radioactivity studies. Results are also in agreement with values reported from other Gulf regions. The computed values of sediment-water distribution coefficients Kd, are lower than the values given by IAEA. Measurements were carried out for bottom sediments, biota samples like fish, oyster, sponge, seashell, mangrove, crab, shrimp, starfish, dugong and algae. The 'concentration factors' reported for biota samples are below the levels published by IAEA and cause no significant impact on human health for seafood consumers in Qatar.
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| 21. |
- Andersson, Emil, et al.
(författare)
-
Facilitating clinically relevant skin tumor diagnostics with spectroscopy-driven machine learning
- 2024
-
Ingår i: iScience. - 2589-0042. ; 27:5
-
Tidskriftsartikel (refereegranskat)abstract
- In the dawning era of artificial intelligence (AI), health care stands to undergo a significant transformation with the increasing digitalization of patient data. Digital imaging, in particular, will serve as an important platform for AI to aid decision making and diagnostics. A growing number of studies demonstrate the potential of automatic pre-surgical skin tumor delineation, which could have tremendous impact on clinical practice. However, current methods rely on having ground truth images in which tumor borders are already identified, which is not clinically possible. We report a novel approach where hyperspectral images provide spectra from small regions representing healthy tissue and tumor, which are used to generate prediction maps using artificial neural networks (ANNs), after which a segmentation algorithm automatically identifies the tumor borders. This circumvents the need for ground truth images, since an ANN model is trained with data from each individual patient, representing a more clinically relevant approach.
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| 22. |
- Andersson, Mikael, et al.
(författare)
-
Modelling the spread of penicillin-resistant Streptococcus pneumoniae in day-care and evaluation of intervention.
- 2005
-
Ingår i: Statistics in Medicine. - : Wiley. - 0277-6715 .- 1097-0258. ; 24:23, s. 3593-607
-
Tidskriftsartikel (refereegranskat)abstract
- In 1995, a disease control and intervention project was initiated in Malmöhus county in southern Sweden to limit the spread of penicillin-resistant pneumococci. Since most of the carriers of pneumococci are preschool children, and since most of the spread is believed to take place in day-care, a mathematical model, in the form of a stochastic process, for the spread in a day-care group was constructed. Effects of seasonal variation and size of the day-care group were particularly considered. The model was then used for comparing results from computer simulations without and with intervention. Results indicate that intervention is highly effective in day-care groups with more than ten children during the second half of the year.
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| 23. |
- Baureus Koch, Catrin, et al.
(författare)
-
Interaction between weak low frequency magnetic fields and cell membranes.
- 2003
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462. ; 24:6, s. 395-402
-
Tidskriftsartikel (refereegranskat)abstract
- The question of whether very weak low frequency magnetic fields can affect biological systems, has attracted attention by many research groups for quite some time. Still, today, 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 low frequency (ELF) magnetic fields on the transport of Ca2+ was studied in a biological system consisting of highly purified plasma membrane vesicles. We tested two quantum mechanical theoretical models that assume that biologically active ions can be bound to a channel protein and influence the opening state of the channel. Vesicles were exposed for 30 min at 32 °C and the calcium efflux was studied using radioactive 45Ca as a tracer. Static magnetic fields ranging from 27 to 37 T and time varying magnetic fields with frequencies between 7 and 72 Hz and amplitudes between 13 and 114 T (peak) were used. We show that suitable combinations of static and time varying magnetic fields directly interact with the Ca2+ channel protein in the cell membrane, and we could quantitatively confirm the model proposed by Blanchard. Bioelectromagnetics 24:395-402, 2003. © 2003 Wiley-Liss, Inc.
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| 24. |
- Belyaev, IY, et al.
(författare)
-
Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation
- 2006
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 27:4, s. 295-306
-
Tidskriftsartikel (refereegranskat)abstract
- We investigated whether exposure of rat brain to microwaves (MWs) of global system for mobile communication (GSM) induces DNA breaks, changes in chromatin conformation and in gene expression. An exposure installation was used based on a test mobile phone employing a GSM signal at 915 MHz, all standard modulations included, output power level in pulses 2 W, specific absorption rate (SAR) 0.4 mW/g. Rats were exposed or sham exposed to MWs during 2 h. After exposure, cell suspensions were prepared from brain samples, as well as from spleen and thymus. For analysis of gene expression patterns, total RNA was extracted from cerebellum. Changes in chromatin conformation, which are indicative of stress response and genotoxic effects, were measured by the method of anomalous viscosity time dependencies (AVTD). DNA double strand breaks (DSBs) were analyzed by pulsed-field gel electrophoresis (PFGE). Effects of MW exposure were observed on neither conformation of chromatin nor DNA DSBs. Gene expression profiles were obtained by Affymetrix U34 GeneChips representing 8800 rat genes and analyzed with the Affymetrix Microarray Suite (MAS) 5.0 software. In cerebellum from all exposed animals, I I genes were upregulated in a range of 1.34-2.74 fold and one gene was downregulated 0.48-fold (P <.0025). The induced genes encode proteins with diverse functions including neurotransmitter regulation, blood-brain barrier (BBB), and melatonin production. The data shows that GSM MWs at 915 MHz did not induce PFGE-detectable DNA double stranded breaks or changes in chromatin conformation, but affected expression of genes in rat brain cells. Bioelectromagnetics 27:295-306, 2006. (c) 2006 Wiley-Liss, Inc.
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| 25. |
- Belyaev, I Y, et al.
(författare)
-
915 MHz microwaves and 50 Hz magnetic field affect chromatin conformation and 53BP1 foci in human lymphocytes from hypersensitive and healthy persons
- 2005
-
Ingår i: Bioelectromagnetics. - : Wiley. - 0197-8462 .- 1521-186X. ; 26:3, s. 173-184
-
Tidskriftsartikel (refereegranskat)abstract
- We used exposure to microwaves from a global system for mobile communication (GSM) mobile phone (915 MHz, specific absorption rate (SAR) 37 mW/kg) and power frequency magnetic field (50 Hz, 15 mu T peak value) to investigate the response of lymphocytes from healthy subjects and from persons reporting hypersensitivity to electromagnetic field (EMF). The hypersensitive and healthy donors were matched by gender and age and the data were analyzed blind to treatment condition. The changes in chromatin conformation were measured with the method of anomalous viscosity time dependencies (AVTD). 53BP1 protein, which has been shown to colocalize in foci with DNA double strand breaks (DSBs), was analyzed by immunostaining in situ. Exposure at room temperature to either 915 MHz or 50 Hz resulted in significant condensation of chromatin, shown as AVTD changes, which was similar to the effect of heat shock at 41 degrees C. No significant differences in responses between normal and hypersensitive subjects were detected. Neither 915 MHz nor 50 Hz exposure induced 53BP1 foci. On the contrary, a distinct decrease in background level of 53BP1 signaling was observed upon these exposures as well as after heat shock treatments. This decrease correlated with the AVTD data and may indicate decrease in accessibility of 53BP1 to antibodies because of stress-induced chromatin condensation. Apoptosis was determined by morphological changes and by apoptotic fragmentation of DNA as analyzed by pulsed-field gel electrophoresis (PFGE). No apoptosis was induced by exposure to 50 Hz and 915 MHz microwaves. In conclusion, 50 Hz magnetic field and 915 MHz microwaves under specified conditions of exposure induced comparable responses in lymphocytes from healthy and hypersensitive donors that were similar but not identical to stress response induced by heat shock.
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| 26. |
- 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.
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| 27. |
- Bergqvist, Lennart, et al.
(författare)
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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.
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| 28. |
- Björk, Per, et al.
(författare)
-
Conjugated polythiophene probes target lysosome-related acidic vacuoles in cultured primary cells
- 2007
-
Ingår i: Molecular and Cellular Probes. - : Elsevier BV. - 0890-8508. ; 21:5-6, s. 329-337
-
Tidskriftsartikel (refereegranskat)abstract
- Conformation-sensitive optical probes for studying biological processes and structures are of great interest. The present work shows for the first time that conjugated polyelectrolyte (CPE) probes can be used for specific targeting of chromatin, nuclear and cytoplasmatic vesicles, and cytoskeletal components in a complex system of cultured cells. One of the probes could also be used for vital staining of live cells. When bound to different entities, the polythiophene derivative probes emitted light with different colors due to the unique spectral properties of these conformation sensitive probes. The physical pre-requisites for binding could also be exploited for characterization of the target. Unexpectedly, lysosome-related acidic vacuoles were targeted in cultured primary cells by both anionic, cationic, and zwitter-ionic polythiophene derivatives. Pre-treatment with Bafilomycin A1, a specific inhibitor of vacuolar-type H+-ATPase, caused redistribution of the staining. The targeting of lysosome-related acidic vesicles could not be demonstrated in transformed cells (melanoma, neuroblastoma, and prostate cancer cell lines), indicating a difference in the localization, structure, accessibility, or quantity of the target in cultured normal cells as compared with the malignant cell lines. The chemical nature of the conjugated polyelectrolyte complex in the cytoplasmatic vacuoles remains elusive.
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| 29. |
- Blad, Börje, et al.
(författare)
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Improvements in The Hardware of The Lund Impedance Tomography System
- 1992
-
Ingår i: Clinical Physics and Physiological Measurement. - 0143-0815. ; 13, s. 15-17
-
Tidskriftsartikel (refereegranskat)abstract
- The objective of this study is to improve the quality of the hardware of the existing Lund impedance tomography system. Improvement in the current generator and different isolation proposals are presented.
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| 30. |
- Bolmsjö, Magnus S., et al.
(författare)
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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.
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| 31. |
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| 32. |
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| 33. |
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| 34. |
- Carlsson, Goran, et al.
(författare)
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The effect of total body microwave hyperthermia and hepatic artery ligation on liver tumors—an experimental study in rats
- 1983
-
Ingår i: Journal of Surgical Oncology. - : Wiley. - 0022-4790 .- 1096-9098. ; 22:1, s. 37-40
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of general microwave hyperthermia and hepatic artery ligation (HAL) was tested on Wistar rats with a transplanted N‐methyl‐N‐nitroso‐guanidine‐induced adenocarcinoma in the liver. Total body hyperthermia (41.5°C for 1 hour, three times during 24 hours) was given on the same day as HAL, and 1, 2, and 3 days after. HAL induced a slower tumor growth than untreated controls. No additive effect was registered when total body microwave hyperthermia was added to HAL. When hyperthermia was added 2 days after HAL, there was a transient decrease in tumor volume as in the HAL series. Total body microwave hyperthermia added 3 days after HAL induced a faster tumor growth than after HAL alone. When hyperthermia was added the same day and 1 day after HAL, there was a 50% mortality.
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| 35. |
- Ceberg, Crister, et al.
(författare)
-
A comparative study on the pharmacokinetics and biodistribution of boronated porphyrin (BOPP) and sulfhydryl boron hydride (BSH) in the RG2 rat glioma model
- 1995
-
Ingår i: Journal of Neurosurgery. - 0022-3085. ; 83:1, s. 86-92
-
Tidskriftsartikel (refereegranskat)abstract
- Boron neutron capture therapy is a treatment modality for cancer that depends on the specific uptake of boron by the tumor cells. The infiltrative growth of malignant gliomas requires that boron reach and accumulate in migrating cells outside the margin of the tumor; thus, it is important that the biodistribution of new boron compounds is also studied in the surrounding healthy brain tissue. This study is undertaken in the present work, in which the biodistribution and pharmacokinetics of sulfhydryl boron hydride (BSH) and boronated porphyrin (BOPP) in the RG2 rat glioma model are investigated. This model mimics the characteristics of human glioma with cells migrating into the surrounding brain. The animals were infused intravenously with either BSH (25 micrograms or 175 micrograms of boron per gram of body weight) or BOPP (12 micrograms of boron per gram body weight). For the low dose of BSH, the maximum tumor-boron content was 8 ppm at approximately 9 hours after the infusion with a tumor-to-blood ratio of 0.6. At the higher dose, the corresponding figures were 15 ppm after 12 hours with a tumor-to-blood ratio of 0.5. For BOPP, a tumor-boron concentration of 81 ppm was achieved 24 hours after the infusion and sustained in that range for at least 72 hours. The tumor-to-blood ratio at 24 hours was slightly above 6, but continued to increase as the blood was cleared. These results indicate that both compounds are spread into the normal brain tissue following the same pathways as the migrating tumor cells and in this way can be taken up even in distant tumor cell foci.
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| 36. |
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| 37. |
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| 38. |
- Ceberg, Crister, et al.
(författare)
-
Enhanced boron uptake in RG 2 rat gliomas by electropermeabilization in vivo--a new possibility in boron neutron capture therapy
- 1994
-
Ingår i: Anti-Cancer Drugs. - 0959-4973. ; 5:4, s. 463-466
-
Tidskriftsartikel (refereegranskat)abstract
- Accumulation of boron in tumor tissue is an indispensable requirement for boron neutron capture therapy and it is important that the uptake is as high as possible. In this work we have studied the influence of electropermeabilization in vivo on the uptake of boron in normal and RG 2 glioma bearing Fischer 344 rats. Two different boron compounds, a sulfhydryl boron hydride (BSH) and a boronated porphyrin (BOPP), have been investigated. The rats were infused intravenously during 5 min with 175 micrograms BSH/g body weight or 12 micrograms BOPP/g body weight. Two electrodes were placed 5 mm apart in the brain and electropermeabilization was performed with eight square 400 V pulses at 4 and 7 min after the end of the infusion. After 6 h the animals were killed, and the boron content in the tumors and the surrounding brain was measured with neutron-activated autoradiography. In electropermeabilized healthy animals the BOPP uptake was low and limited to the electrode lesions, whereas BSH was spread extensively throughout the hemisphere. Rats with gliomas showed doubled (BOPP) to 10-fold (BSH) uptake of boron in the tumor when electropermeabilization was performed as compared with untreated animals. We conclude that electropermeabilization in the future may provide an interesting possibility to increase the uptake of certain boron compounds before neutron capture therapy.
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| 39. |
- Ceberg, Crister, et al.
(författare)
-
Neutron capture imaging of 10B in tissue specimens
- 1993
-
Ingår i: Radiotherapy and Oncology. - 1879-0887. ; 26:2, s. 139-146
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Tidskriftsartikel (refereegranskat)abstract
- Boron Neutron Capture Therapy (BNCT) is an attractive concept for radiation treatment of malignant tumours. The patients receive a 10B-carrying compound with selective uptake in tumour cells, after which they are irradiated with epithermal neutrons. Theoretically, the tumour cells are killed by the high-LET particles produces in 10B(n, alpha)7Li reactions inside or close to the cell nucleus, while healthy brain cells with no boron uptake will be spared. In practice, a successful BNCT depends on the actual boron-distribution in the tissue, and consequently a new boron-compound aimed for BNCT must undergo detailed bio-distribution studies before clinical trials. In experimental work there is accordingly a great need for methods for quantitative bio-distribution measurements in tissue samples. In this paper we present an improved technique for neutron activated autoradiography providing quantitative boron images of freeze-sectioned tissue specimens from highly malignant rat brain gliomas. Particular attention has been paid to the correlation with the morphology of the specimens and to the altered self-absorption properties due to freeze-drying. A self-absorption correction factor for tumour tissue has been experimentally determined.
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| 40. |
- 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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| 41. |
- Dahlstrand, Ulf, et al.
(författare)
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Photoacoustic imaging for three-dimensional visualization and delineation of basal cell carcinoma in patients
- 2020
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Ingår i: Photoacoustics. - : Elsevier BV. - 2213-5979. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: Photoacoustic (PA) imaging is an emerging non-invasive biomedical imaging modality that could potentially be used to determine the borders of basal cell carcinomas (BCC) preoperatively in order to reduce the need for repeated surgery.Methods: Two- and three-dimensional PA images were obtained by scanning BCCs using 59 wavelengths in the range 680-970 nm. Spectral unmixing was performed to visualize the tumor tissue distribution. Spectral signatures from 38 BCCs and healthy tissue were compared ex vivo.Results and discussion: The PA spectra could be used to differentiate between BCC and healthy tissue ex vivo (p < 0.05). Spectral unmixing provided visualization of the overall architecture of the lesion and its border.Conclusion: PA imaging can be used to differentiate between BCC and healthy tissue and can potentially be used to delineate tumors prior to surgical excision.
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| 42. |
- 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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| 43. |
- Darte, Lennart, et al.
(författare)
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Quality control of 99mTc-radiopharmaceuticals - Evaluation of GCS minicolumns in routine clinical work with scintillation cameras
- 1980
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Ingår i: European Journal Of Nuclear Medicine. - 0340-6997. ; 5:6, s. 521-527
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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.
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| 44. |
- Diffner, Eva, et al.
(författare)
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Expression of VEGF and VEGF Receptors in Childhood Precursor B-cell Acute Lymphoblastic Leukemia Evaluated by Immunohistochemistry
- 2009
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Ingår i: Journal of pediatric hematology/oncology (Print). - : Wolters Kluwer. - 1077-4114 .- 1536-3678. ; 31:9, s. 696-701
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Tidskriftsartikel (refereegranskat)abstract
- Perturbation in the expression and signaling pathways of vascular endothelial growth factor (VEGF) has been linked to pathogenesis of hematologic malignancies. We investigated the expression and clinical importance of VEGF and two of its receptors, VEGFR-1 and VEGFR-2, in childhood precursor B-cell acute lymphoblastic leukemia (pre-B ALL) by using immunohistochemistry. These angiogenic proteins were expressed in the majority of leukemic bone marrow samples. Notably, pre-B ALL patients had significantly increased expression of VEGFR-1 compared with no expression in the nonmalignant group, indicating a link between VEGFR-1 protein expression and pre-B ALL. These novel findings suggest that VEGFR-1 may have clinical importance in childhood pre-B ALL.
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| 45. |
- Dock, H., et al.
(författare)
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Maintenance of the E.coli dcm Methylation of the CMV Promoter, in Contrast to Hypomethylation of the Recognition Sequence of Transcription Factor NFkB in Transfected GBM Cells
- 2016
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Ingår i: Cloning & Transgenesis. - : OMICS Publishing Group. - 2168-9849. ; 5:1
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Tidskriftsartikel (refereegranskat)abstract
- The human cytomegalovirus (CMV) immediate early promoter has been extensively used to drive target gene expression in transgenic mammalian cells. DNA methylation of the CMV promoter has been shown to be the reason for a reduced promoter activity and silencing of the target gene. We have established an in vitro model system, in which human brain cancer cells (glioblastoma multiforme, GBM) were transfected with pAdTrack-CMV-GFP plasmid, isolated from a dcm positive (dcm+) E. coli strain. We found that in two CCTGG sequences located at position from -304 to -300 nt and from -497 to -493 nt of the CMV promoter region, the internal C was methylated in all analyzed clones, i.e., the E. coli dcm methylation pattern is maintained in the CMV promoter region after its integration into the human genome. In contrast, we found that the recognition sites for the transcription factor NFkB and certain other transcription factors in the enhancer region of the CMV promoter (from -107 to -270 nt) were hypomethylated. This might explain why the CMV promoter maintained an active mode, driving the GFP expression despite the demonstrated methylation of the CMV promoter. We noticed that the CCTGG sequence is also contained in the binding sequence motif of transcription factor NFkB. Hence we have comprehensively studied transcription factors through a database searching, and the responsive elements that contain dcm methylation sequences CCW(A/T)GG. A list of transcription factors and the corresponding regulated genes are presented.
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| 46. |
- Eberhardt, Jacob, et al.
(författare)
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Blood-brain barrier permeability and nerve cell damage in rat brain 14 and 28 days after exposure to microwaves from GSM mobile phones.
- 2008
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Ingår i: Electromagnetic Biology and Medicine. - : Informa UK Limited. - 1536-8386 .- 1536-8378. ; 27:3, s. 215-229
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the effects of global system for mobile communication (GSM) microwave exposure on the permeability of the blood-brain barrier and signs of neuronal damage in rats using a real GSM programmable mobile phone in the 900 MHz band. Ninety-six non-anaesthetized rats were either exposed to microwaves or sham exposed in TEM-cells for 2 h at specific absorption rates of average whole-body Specific Absorption Rates (SAR) of 0.12, 1.2, 12, or 120 mW/kg. The rats were sacrificed after a recovery time of either 14 or 28 d, following exposure and the extravazation of albumin, its uptake into neurons, and occurrence of damaged neurons was assessed. Albumin extravazation and also its uptake into neurons was seen to be enhanced after 14 d (Kruskal Wallis test: p = 0.02 and 0.002, respectively), but not after a 28 d recovery period. The occurrence of dark neurons in the rat brains, on the other hand, was enhanced later, after 28 d (p = 0.02). Furthermore, in the 28-d brain samples, neuronal albumin uptake was significantly correlated to occurrence of damaged neurons (Spearman r = 0.41; p < 0.01).
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| 47. |
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| 48. |
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| 49. |
- Engström, Per E., et al.
(författare)
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Effect of high voltage electrical pulses on subcutaneous glioma tumours on rats
- 1998
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Ingår i: Bioelectrochemistry and Bioenergetics. - 0302-4598. ; 47:1, s. 163-166
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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.
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| 50. |
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