| 1. |
- Bendel, Olof, et al.
(författare)
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Reproducible loss of CA1 neurons following carotid artery occlusion combined with halothane-induced hypotension
- 2005
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Ingår i: Brain Research. - : Elsevier. - 0006-8993 .- 1872-6240. ; 1033:2, s. 135-142
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Tidskriftsartikel (refereegranskat)abstract
- The 2-vessel occlusion approach to produce global ischemia in rats requires concomitant reduction of systemic blood pressure. We have utilized the hypotensive effect of halothane administrated by artificial respiration to prevent respiratory arrest and to ensure stable physiological conditions. Systemic blood pressure was reduced to 40-45 mmHg by instant adjustments of the halothane concentration. Bilateral occlusion of the carotid arteries caused a profound and reproducible ischemia, as analyzed by laser-Doppler flowmetry. In the rats exposed to 11, 12, or 13 min of ischemia, 5% died and 5% developed seizures. The extent of neuronal death in CA1 was highly correlated to the duration of ischemia. Following 11 min of ischemia, CA1 neuronal cell death, as analyzed by Fluoro-Jade, was absent 1 day after injury, variable at day 4, and consistent at day 7. The numbers of cresyl violet- and NeuN-positive neurons at day 7 were 8% and 20% of control, respectively. OX42 immunoreactivity was low and variable at day 4, but pronounced at day 7. In conclusion, this rat global ischemia model is relatively simple to perform, has a low mortality, and produces a profound and highly reproducible delayed cell death of hippocampal CA1 neurons.
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| 2. |
- Bergmann, Olaf, et al.
(författare)
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Evidence for Cardiomyocyte Renewal in Humans
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 324:5923, s. 98-102
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Tidskriftsartikel (refereegranskat)abstract
- It has been difficult to establish whether we are limited to the heart muscle cells we are born with or if cardiomyocytes are generated also later in life. We have taken advantage of the integration of carbon-14, generated by nuclear bomb tests during the Cold War, into DNA to establish the age of cardiomyocytes in humans. We report that cardiomyocytes renew, with a gradual decrease from 1% turning over annually at the age of 25 to 0.45% at the age of 75. Fewer than 50% of cardiomyocytes are exchanged during a normal life span. The capacity to generate cardiomyocytes in the adult human heart suggests that it may be rational to work toward the development of therapeutic strategies aimed at stimulating this process in cardiac pathologies.
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| 3. |
- Bergmann, Olaf, et al.
(författare)
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Turnover of Human Cardiomyocytes
- 2008
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Ingår i: Circulation Research. - 0009-7330. ; 103:12, s. 1494-1495
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Konferensbidrag (refereegranskat)
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| 4. |
- Druid, Henrik, et al.
(författare)
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Evaluation of the role of abstinence in heroin overdose deaths using segmental hair analysis
- 2007
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Ingår i: Forensic Science International. - : Elsevier BV. - 0379-0738 .- 1872-6283. ; 168:2-3, s. 223-226
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Tidskriftsartikel (refereegranskat)abstract
- In the body heroin is rapidly metabolized to 6-acetylmorphine and morphine. Victims of lethal heroin overdose often present with fairly low blood concentrations of morphine. Reduced tolerance due to abstinence has been proposed to account for this finding. The aim of the present study was to examine the role of abstinence in drug-related deaths by comparing recent and past exposure to opioids using segmental hair analysis with the postmortem blood morphine concentrations in deceased heroin users. The study included 60 deceased drug addicts in the Stockholm area, Sweden. In 32 cases, death was not related to heroin intake. In 18 of the 28 heroin fatalities, opioids were absent in the most recent hair segment, suggesting a reduced tolerance to opioids. However, the blood morphine levels were similar to those found in the 10 subjects that showed continuous opioid use. Hair and blood analysis disclosed an extensive use of additional drugs that directly or indirectly may influence the opioid system. The results suggest that abstinence is not a critical factor for heroin overdose death. Obviously tolerant subjects die after intake of similar doses. Other factors, particularly polydrug use, seem to be more causally important for these deaths.
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| 5. |
- Kugelberg, Fredrik, 1974-, et al.
(författare)
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Influence of blood loss on the pharmacokinetics of citalopram
- 2006
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Ingår i: Forensic Science International. - : Elsevier BV. - 0379-0738 .- 1872-6283. ; 161:2-3, s. 163-168
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Tidskriftsartikel (refereegranskat)abstract
- Extended blood loss results in several compensatory physiological mechanisms, including transfer of extravascular fluid into the blood circulation. If drugs are present in the body, this fluid exchange may imply that blood drug concentrations found in a trauma victim may differ from the concentrations present at the time of the trauma. To address this issue, an animal model was used to investigate the influence of blood loss on pre-existing levels of the antidepressant drug citalopram and its demethylated metabolites. Rats were administered citalopram either acutely (40 mg/kg, orally) or chronically (20 mg/kg daily, subcutaneously) for 6 days using osmotic pumps. In the experimental rats, blood loss was accomplished by withdrawing 0.8 mL blood at 10 min intervals during 70 min. In the control rats, blood was withdrawn at 0 and 70 min only. Blood, brain and lung drug concentrations were analyzed with an enantioselective HPLC method. In the chronically treated rats, the ratios between final and initial citalopram concentrations were 1.08 ± 0.15 and 1.01 ± 0.09 in the experimental rats and controls, respectively, indicating no major effect of blood loss. In contrast, acute oral administration resulted in increased ratios in the exsanguinated rats as compared to controls (1.84 ± 0.50 versus 0.73 ± 0.07, p = 0.0495). In conclusion, the observation of increased blood drug levels in the acute oral rats indicates that absorption of fluid from the gastrointestinal tract may be important in the intravascular refill. Further, in the interpretation of post-mortem blood levels of drugs, these physiological mechanisms should be taken into account. © 2006 Elsevier Ireland Ltd. All rights reserved.
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| 6. |
- Strandberg, Joakim J, et al.
(författare)
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Toxicological analysis in rats subjected to heroin and morphine overdose
- 2006
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Ingår i: Toxicology Letters. - : Elsevier BV. - 0378-4274 .- 1879-3169. ; 166:1, s. 11-18
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Tidskriftsartikel (refereegranskat)abstract
- In heroin overdose deaths the blood morphine concentration varies substantially. To explore possible pharmacokinetic explanations for variable sensitivity to opiate toxicity we studied mortality and drug concentrations in male Sprague-Dawley rats. Groups of rats were injected intravenously (i.v.) with heroin, 21.5 mg/kg, or morphine, 223 mg/kg, causing a 60–80% mortality among drug-naïve rats. Additional groups of rats were pre-treated with morphine for 14 days, with or without 1 week of subsequent abstinence. Brain, lung and blood samples were analyzed for 6-acetylmorphine, morphine, morphine-3-glucuronide and morphine-6-glucuronide. i.v. morphine administration to drug-naïve rats resulted in both rapid and delayed deaths. The brain morphine concentration conformed to an exponential elimination curve in all samples, ruling out accumulation of morphine as an explanation for delayed deaths. This study found no support for formation of toxic concentration of morphine-6-glucuronide. Spontaneous death among both heroin and morphine rats occurred at fairly uniform brain morphine concentrations. Morphine pre-treatment significantly reduced mortality upon i.v. morphine injection, but the protective effect was less evident upon i.v. heroin challenge. The morphine pre-treatment still afforded some protection after 1 week of abstinence among rats receiving i.v. morphine, whereas rats given i.v. heroin showed similar death rate as drug-naïve rats.
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