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- Bjarnadottir, G. D., et al.
(author)
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Intravenous Use of Prescription Psychostimulants; A Comparison of the Pattern and Subjective Experience between Different Methylphenidate Preparations, Amphetamine and Cocaine
- 2016
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In: European Addiction Research. - : S. Karger AG. - 1022-6877 .- 1421-9891. ; 22:5, s. 259-267
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Journal article (peer-reviewed)abstract
- Background/Aims: Methylphenidate (MPH) has been the most commonly used intravenous (i.v.) substance in Iceland in recent years. In Iceland, MPH is available in 3 forms: immediate-release (IR) tablets (MPH IR, short-acting), sustainable-release (SR) capsules (MPH SR, long-acting) and osmotic-release (OROS) tablets (MPH OROS, long-acting). The aims of the study were to compare the pattern and subjective effects of i.v. MPH use to other i.v. psychostimulants and examine whether the pattern of use differs among MPH preparations. Methods: This is a nationwide descriptive study. Information was collected from 95 i.v. substance users undergoing inpatient detoxification and reporting i.v. MPH use in the last 30 days using a semi-structured interview. Results: MPH SR was both the most commonly used (96%) and preferred i.v. psychostimulant (57%). The intensity and duration of 'euphoria' did not differ between cocaine and MPH SR. No participant reported MPH OROS as their preferred substance even though a third had used it in the past month. Conclusions: The pattern of i.v. MPH use is similar to other psychostimulants among treatment seeking patients. MPH OROS was the least preferred i.v. psychostimulant, despite having the largest market share in Iceland. The results indicate that MPH OROS has less abuse potential than other MPH preparations. (C) 2016 S. Karger AG, Basel
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| 2. |
- Bjarnadottir, G. D., et al.
(author)
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Methylphenidate disintegration from oral formulations for intravenous use by experienced substance users
- 2017
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In: Drug and Alcohol Dependence. - : Elsevier BV. - 0376-8716. ; 178, s. 165-169
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Journal article (peer-reviewed)abstract
- Background and aims: Methylphenidate (MPH) is a prescription stimulant used to treat attention-deficit hyperactivity disorder. MPH is currently the preferred substance among most intravenous (i.v.) substance users in Iceland. Four types of MPH preparations were available in Iceland at the time of study: Immediate-release (IR), sustained-release (SR), osmotic controlled-release oral delivery (OROS) tablet and osmotic-controlled release (OCR). MPH OROS has previously been rated the least desirable by i.v. users and we hypothesized that this was associated with difficulty of disintegrating MPH from OROS formulation. The aim of the study was to measure the amount of MPH and the viscosity of the disintegrated solutions that were made from the four MPH formulations by four i.v.-users and non-users. Methods: A convenience sample of four i.v. substance users and 12 non-users. Non-users imitated the methods applied by experienced i.v. substance users for disintegrated MPH formulations. Results: Both groups managed to disintegrate over 50% of MPH from IR and SR formulations but only 20% from OROS (p < 0.0001). The viscosity of the disintegrated MPH was significantly higher for MPH OROS and MPH OCR and the preparation was significantly more time-consuming than for the other MPH samples. No differences were observed between users and non-users. Conclusions: To our knowledge, this is the first investigation of viscosity and the amount of disintegrated MPH from prescription drugs for i.v. use. The results indicate that the ease of disintegration, amount of MPH and viscosity may explain the difference in popularity for i.v. use between different MPH formulations.
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| 3. |
- Bjarnadottir, G. D., et al.
(author)
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Prevalent intravenous abuse of methylphenidate among treatment-seeking patients with substance abuse disorders: A descriptive population-based study
- 2015
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In: Journal of Addiction Medicine. - : Lippincott Williams and Wilkins. - 1932-0620. ; 9:3, s. 188-194
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Journal article (peer-reviewed)abstract
- Objectives: Prescription rates of methylphenidate (MPH) are sharply rising in most Western countries. Although it has been reported that MPH has abuse potential, little is known about the prevalence of intravenous (IV) abuse of MPH. The aim of the study was to investigate the prevalence of IV MPH abuse among treatment-seeking IV substance abusers in Iceland. Methods: This is a descriptive population-based study using a semistructured interview assessing sociodemographics, substance abuse history, and the method of administration of 108 IV substance abusers. During 1 year, consecutively admitted adult inpatients with substance use disorder at any detoxification center in Iceland that reported any IV substance abuse in the past 30 days were invited to participate. Abuse was defined as nontherapeutic use of a substance to gain psychological or physiological effect. Results: Prevalence of any IV MPH abuse among participants was 88% in the last 30 days (95% confidence interval [CI], 0.82-0.94) and MPH was the most commonly abused substance (65%) and the preferred substance (63%). Around one third (30%) reportedMPH as the first IV substance ever abused. However, among those reporting a shorter history than 10 years of IV abuse, 42% reported MPH as the first IV substance ever abused. Conclusions: This first nationwide study on IV abuse ofMPH shows that it is common among treatment-seeking IV abusers in Iceland and suggests that MPH has high abuse potential. Therefore, both the use and possible abuse of MPH in those with high abuse potential should be monitored, especially in countries where MPH prescriptions rates are on the rise. Copyright © 2015 American Society of Addiction Medicine.
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| 4. |
- Corderfeldt, Anna, et al.
(author)
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Non-invasive and invasive measurement of skeletal muscular oxygenation during isolated limb perfusion
- 2023
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In: Perfusion-Uk. - : SAGE Publications. - 0267-6591. ; 38:5, s. 1019-1028
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Journal article (peer-reviewed)abstract
- Background: Isolated limb perfusion (ILP) is a regional surgical treatment for localized metastatic disease. High doses of chemotherapeutic agents are administered within an extracorporeal circulated isolated extremity, treating the metastasis, while systemic toxicity is avoided. To our knowledge, indexed oxygen supply/demand relationship during ILP has not previously been described. Our aim was to measure and describe oxygen metabolism, specifically oxygen delivery, consumption, and extraction, in an isolated leg/arm during ILP. Also investigate whether invasive oxygenation measurement during ILP correlates and can be used interchangeable with the non-invasive method, near infrared spectroscopy (NIRS). Methods: Data from 40 patients scheduled for ILP were included. At six time points blood samples were drawn during the procedure. DO2, VO2, and O2ER were calculated according to standard formulas. NIRS and hemodynamics were recorded every 10 min. Results: For all observations, the mean of DO2 was 190 +/- 59 ml/min/m(2), VO2 was 35 +/- 8 ml/min/m(2), and O2ER was 21 +/- 8%. VO2 was significantly higher in legs compared to arms (38 +/- 8 vs. 29 +/- 7 ml/min/m(2), p=0.02). Repeated measures showed a significant decrease in DO2 in legs (209 +/- 65 to 180 +/- 66 ml/min/m(2), p=<0.01) and in arms (252 +/- 72 to 150 +/- 57 ml/min/m(2), p=<0.01). Significant increase in O2ER in arms was also found (p=0.03). Significant correlation was detected between NIRS and venous extremity oxygen saturation (SveO(2)) (r(rm)=0.568, p=<. 001, 95% CI 0.397-0.701). When comparing SveO(2) and NIRS using a Bland-Altman analysis, the mean difference (bias) was 8.26 +/- 13.03 (p=<. 001) and the limit of agreement was - 17.28-33.09, with an error of 32.5%. Conclusion: DO2 above 170 ml/min/m(2) during ILP kept O2ER below 30% for all observations. NIRS correlates significant to SveO(2); however, the two methods do not agree sufficiently to work interchangeable.
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| 6. |
- Klassen, Henry, et al.
(author)
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Neural precursors isolated from the developing cat brain show retinal integration following transplantation to the retina of the dystrophic cat
- 2007
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In: Veterinary Ophthalmology. - : Wiley. - 1463-5216 .- 1463-5224. ; 10:4, s. 245-253
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Journal article (peer-reviewed)abstract
- The cat has served as an important nonrodent research model for neurophysiology and retinal degenerative disease processes, yet very little is known about feline neural precursor cells. To culture these cells and evaluate marker expression, brains were dissected from 45-day-old fetuses, enzymatically dissociated, and grown in the presence of EGF, bFGF and PDGF. Expanded cells widely expressed nestin, Sox2, Ki-67, fusin (CXCR4) and vimentin, while subpopulations expressed A2B5, GFAP, or beta-III tubulin. Precursors prelabeled with BrdU and/or transduced with a recombinant lentivirus that expresses GFP were transplanted subretinally in five dystrophic Abyssinian cats. Two to 4 weeks following surgery, histology showed survival of grafted cells in three of the animals. Labeled cells were found in the neuroretina and RPE layer, as well as in the vitreous and the vicinity of Bruch's membrane. There was no evidence of an immunologic response in any of the eyes. Neural precursor cells can therefore be cultured from the developing cat brain and survive as allografts for up to 4 weeks without immune suppression. The feasibility of deriving and transplanting feline neural precursor cells, combined with the availability of the dystrophic Abyssinian cat, provide a new feline model system for the study of retinal repair.
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