| 1. |
- Snipstad, Sofie, et al.
(author)
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Labeling nanoparticles : Dye leakage and altered cellular uptake
- 2017
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In: Cytometry Part A. - : John Wiley & Sons. - 1552-4922 .- 1552-4930. ; 91:8, s. 760-766
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Journal article (peer-reviewed)abstract
- In vitro and in vivo behavior of nanoparticles (NPs) is often studied by tracing the NPs with fluorescent dyes. This requires stable incorporation of dyes within the NPs, as dye leakage may give a wrong interpretation of NP biodistribution, cellular uptake, and intracellular distribution. Furthermore, NP labeling with trace amounts of dye should not alter NP properties such as interactions with cells or tissues. To allow for versatile NP studies with a variety of fluorescence-based assays, labeling of NPs with different dyes is desirable. Hence, when new dyes are introduced, simple and fast screening methods to assess labeling stability and NP-cell interactions are needed. For this purpose, we have used a previously described generic flow cytometry assay; incubation of cells with NPs at 4 and 37C. Cell-NP interaction is confirmed by cellular fluorescence after 37C incubation, and NP-dye retention is confirmed when no cellular fluorescence is detected at 4C. Three different NP-platforms labeled with six different dyes were screened, and a great variability in dye retention was observed. Surprisingly, incorporation of trace amounts of certain dyes was found to reduce or even inhibit NP uptake. This work highlights the importance of thoroughly evaluating every dye-NP combination before pursuing NP-based applications. © 2016 International Society for Advancement of Cytometry.
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| 2. |
- Hostrup, M., et al.
(author)
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β2-Adrenergic stimulation enhances Ca2+ release and contractile properties of skeletal muscles, and counteracts exercise-induced reductions in Na+-K+-ATPase Vmax in trained men
- 2014
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In: Journal of Physiology. - : Wiley. - 0022-3751 .- 1469-7793. ; 592:24, s. 5445-5459
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Journal article (peer-reviewed)abstract
- The aim of the present study was to examine the effect of β2-adrenergic stimulation on skeletal muscle contractile properties, sarcoplasmic reticulum (SR) rates of Ca2+ release and uptake, and Na+-K+-ATPase activity before and after fatiguing exercise in trained men. The study consisted of two experiments (EXP1, n = 10 males, EXP2, n = 20 males), where β2-adrenoceptor agonist (terbutaline) or placebo was randomly administered in double-blinded crossover designs. In EXP1, maximal voluntary isometric contraction (MVC) of m. quadriceps was measured, followed by exercise to fatigue at 120% of maximal oxygen uptake (V˙O2, max ). A muscle biopsy was taken after MVC (non-fatigue) and at time of fatigue. In EXP2, contractile properties of m. quadriceps were measured with electrical stimulations before (non-fatigue) and after two fatiguing 45 s sprints. Non-fatigued MVCs were 6 ± 3 and 6 ± 2% higher (P < 0.05) with terbutaline than placebo in EXP1 and EXP2, respectively. Furthermore, peak twitch force was 11 ± 7% higher (P < 0.01) with terbutaline than placebo at non-fatigue. After sprints, MVC declined (P < 0.05) to the same levels with terbutaline as placebo, whereas peak twitch force was lower (P < 0.05) and half-relaxation time was prolonged (P < 0.05) with terbutaline. Rates of SR Ca2+ release and uptake at 400 nm [Ca2+] were 15 ± 5 and 14 ± 5% (P < 0.05) higher, respectively, with terbutaline than placebo at non-fatigue, but declined (P < 0.05) to similar levels at time of fatigue. Na+-K+-ATPase activity was unaffected by terbutaline compared with placebo at non-fatigue, but terbutaline counteracted exercise-induced reductions in maximum rate of activity (Vmax) at time of fatigue. In conclusion, increased contractile force induced by β2-adrenergic stimulation is associated with enhanced rate of Ca2+ release in humans. While β2-adrenergic stimulation elicits positive inotropic and lusitropic effects on non-fatigued m. quadriceps, these effects are blunted when muscles fatigue.
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| 3. |
- Lindh, Magnus, 1960, et al.
(author)
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Hepatitis C treatment response kinetics and impact of baseline predictors.
- 2011
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In: Journal of Viral Hepatitis. - : Wiley. - 1365-2893 .- 1352-0504. ; 18:6, s. 400-407
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Journal article (peer-reviewed)abstract
- Summary. The optimal duration of treatment for hepatitis C virus (HCV) infections is highly variable but critical for achieving cure (sustained virological response, SVR). We prospectively investigated the impact of age, fibrosis, baseline viraemia and genotype on the early viral kinetics and treatment outcome. Patients treated with peginterferon alfa-2a and ribavirin in standard dosing were included: 49 with genotype 1 treated for 48 weeks and 139 with genotype 2 or 3 treated for 24 weeks. The reduced SVR rates in patients older than 45 years, with severe liver fibrosis or pretreatment viraemia above 400 000 IU/mL were strongly associated with slower second phase declines of HCV RNA. Genotype 2/3 infections responded more rapidly than genotype 1, reaching week 4 negativity (RVR) in 59%vs 22%. We conclude that baseline response predictors such as age, fibrosis and viral load were well reflected by the early viral kinetics as assessed by repeated HCV RNA quantifications. The kinetic patterns and the high relapse rate in genotype 2/3 patients without RVR suggest that this group might benefit from treatment durations longer than 24 weeks.
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| 4. |
- Lindh, Magnus, 1960, et al.
(author)
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Interleukin 28B Gene Variation at rs12979860 Determines Early Viral Kinetics During Treatment in Patients Carrying Genotypes 2 or 3 of Hepatitis C Virus
- 2011
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In: Journal of Infectious Diseases. - : Oxford University Press (OUP). - 1537-6613 .- 0022-1899. ; 203:12, s. 1748-1752
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Journal article (peer-reviewed)abstract
- Single-nucleotide polymorphisms upstream of the interleukin 28B (interferon lambda 3) gene (IL28B) strongly influence treatment efficacy in patients carrying hepatitis C virus (HCV) of genotype 1. In patients receiving 12 or 24 weeks of interferon-ribavirin therapy for infection with genotype 2 or 3 (n = 341), we found that rs12979860 strikingly determined the first phase of viral elimination (P < .001). In patients treated for 24 weeks, rs12979860 also predicted the rate of sustained virologic response (P = .02), especially among those with high baseline HCV RNA levels (P = .002) or older than 45 years (P = .01). Patients carrying CCrs12979860 had higher baseline HCV RNA levels (P < .001) and did not, when treated for 12 weeks, achieve sustained virologic response more often than those carrying CTrs1297986 or TTrs1297986. The results indicate that IL28B gene testing may identify patients carrying genotype 2 or 3 who could benefit from extended treatment.
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| 6. |
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| 7. |
- Pedersen, C., et al.
(author)
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Ribavirin plasma concentration is a predictor of sustained virological response in patients treated for chronic hepatitis C virus genotype 2/3 infection
- 2011
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In: Journal of Viral Hepatitis. - : Wiley. - 1352-0504 .- 1365-2893. ; 18:4, s. 245-51
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Journal article (peer-reviewed)abstract
- In hepatitis C virus (HCV) genotype 1 infection, the likelihood of obtaining sustained virological response (SVR) is associated with higher ribavirin exposure. Such an association has not been demonstrated for HCV genotype 2/3 infection, where a fixed 800 mg daily dosing of ribavirin is generally recommended. The primary aim of this study was to investigate the correlation between ribavirin concentration at day 29 and therapeutic response in patients with HCV genotype 2/3 infection. A total of 382 patients were randomized to 12 or 24 weeks of treatment with pegylated interferon-alfa 2a 180 μg weekly and 800 mg ribavirin daily. Trough plasma concentration of ribavirin was measured at day 29 and week 12 and the primary outcome was SVR (HCV-RNA undetectable 24 weeks after treatment). Of the 382 patients, 355 had a ribavirin concentration available at day 29. SVR was 84% among patients with a ribavirin concentration ≥2 mg/L at day 29 compared to 66% in those with concentrations <2 mg/L (P = 0.002). The corresponding figures in the 12-week treatment group were 74% and 57% (P = 0.12), and in the 24-week treatment group 91% and 75% (P = 0.02), respectively. In a multivariate analysis, ribavirin concentration at day 29 was an independent predictor of SVR (P = 0.002). In conclusion, a higher plasma ribavirin concentration is associated with an increased likelihood of achieving SVR in HCV genotype 2/3 infection. Individualization of ribavirin dosing may be helpful in improving outcome, especially in the presence of unfavourable baseline characteristics. This, however, requires evaluation in a prospective trial.
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| 8. |
- Åslund, Andreas K. O., et al.
(author)
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Nanoparticle delivery to the brain - By focused ultrasound and self-assembled nanoparticle-stabilized microbubbles
- 2015
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In: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 220, s. 287-294
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Journal article (peer-reviewed)abstract
- The blood-brain barrier (BBB) constitutes a significant obstacle for the delivery of drugs into the central nervous system(CNS). Nanoparticles have been able to partly overcome this obstacle and can thus improve drug delivery across the BBB. Furthermore, focused ultrasound in combination with gas filled microbubbles has opened the BBB in a temporospatial manner in animal models, thus facilitating drug delivery across the BBB. In the current study we combine these two approaches in our quest to develop a novel, generic method for drug delivery across the BBB and into the CNS. Nanoparticles were synthesized using the polymer poly(butyl cyanoacrylate) (PBCA), and such nanoparticles have been reported to cross the BBB to some extent. Together with proteins, these nanoparticles self-assemble into microbubbles. Using these novel microbubbles in combination with focused ultrasound, we successfully and safely opened the BBB transiently in healthy rats. Furthermore, we also demonstrated that the nanoparticles could cross the BBB and deliver a model drug into the CNS.
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