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- Agervald, Åsa
(author)
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Maturation and Regulation of Cyanobacterial Hydrogenases
- 2009
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Doctoral thesis (other academic/artistic)abstract
- Accelerated global warming plus an increasing need for energy is an equation not easily solved, thus new forms of sustainable energy production are urgently requested. In this context hydrogen production based on a cyanobacterial system offers an environmentally friendly alternative for energy capture and conversion. Cyanobacteria can produce hydrogen gas from sun light and water through the combination of photosystems and hydrogenases, and are suitable to cultivate in large scale. In the present thesis the maturation process of [NiFe]-hydrogenases is investigated with special focus on transcription of the accessory genes encoding proteins needed for assembly of the large and possibly also for the small hydrogenase subunit. The cyanobacteria used are two N2-fixing, filamentous, heterocystous strains; Nostoc sp. strain PCC 7120 and Nostoc punctiforme PCC 73102. For a biotechnological exploration of hydrogen production tools for regulatory purposes are important. The transcription factor CalA (cyanobacterial AbrB like) (Alr0946 in the genome) in Nostoc sp. strain PCC 7120 was found to be involved in hydrogen metabolism by regulating the transcription of the maturation protein HypC. Further the bidirectional hydrogenase activity was down-regulated in the presence of elevated levels of CalA, a result important to take into account when optimizing cyanobacteria for hydrogen production. CalA regulates at least 25 proteins in Nostoc sp. strain PCC 7120 and one of the down-regulated proteins was superoxide dismutase, FeSOD. The characterization of FeSOD shows that it has a specific and important function in the oxidative stress tolerance of Nostoc sp. stain PCC 7120. Since CalA is involved in regulation of both the hydrogen metabolism as well as stress responses these findings indicate that Alr0946 is an important transcription factor in Nostoc sp. strain PCC 7120 active on a global level in the cell. This thesis adds more knowledge concerning maturation and regulation of cyanobacterial hydrogenases which might be useful for future large scale hydrogen.
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- Greimel, Elfriede R, et al.
(author)
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The European Organization for Research and Treatment of Cancer (EORTC) Quality-of-Life questionnaire cervical cancer module: EORTC QLQ-CX24.
- 2006
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In: Cancer. - : Wiley. - 0008-543X .- 1097-0142. ; 107:8, s. 1812-22
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Journal article (peer-reviewed)abstract
- BACKGROUND: The authors report on the development and validation of a cervical cancer module for the European Organization for Research and Treatment of Cancer (EORTC) Quality-of-Life (QoL) questionnaire (QLQ), which was designed to assess disease-specific and treatment-specific aspects of QoL in patients with cervical cancer. METHODS: The cervical cancer module (EORTC QLQ-CX24) was developed in a multicultural, multidisciplinary setting to supplement the EORTC QLQ-C30 core questionnaire. The QLQ-C30 and the cervical cancer module were administered to 346 patients with cervical cancer who underwent radical hysterectomy and received radiotherapy and chemotherapy. Psychometric analyses were performed by using data from 2 independent samples. RESULTS: The QLQ-CX24 consists of 3 multiitem scales and 5 single-item scales. Multitrait scaling analyses revealed high internal consistencies for the subscales with Cronbach alpha coefficients ranging from .72 to .87 (Symptom Experience, .72; Body Image, .86; Sexual/Vaginal Functioning, .87). Convergent and discriminant validity were fulfilled with scaling errors below 3%. The QLQ-CX24 was capable of discriminating between clinical subgroups. All items exhibited good compliance with <3% missing values. Most patients completed the EORTC QLQ-C30 and the QLQ-CX24 in <15 minutes (86%), and many did not require any assistance to complete the questionnaires (65%). CONCLUSIONS: The current psychometric analyses supported the content and construct validity and the reliability of the EORTC QLQ-CX24 module. This newly developed module is a useful instrument for assessing the QoL of patients who are treated for cervical cancer both in clinical trials and in clinical practice.
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- Jensen, Karin B
(author)
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Brain mechanisms in pain regulation
- 2009
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Doctoral thesis (other academic/artistic)abstract
- The subjective sensitivity to pain differs greatly between individuals and neuroimaging has contributed to the understanding of the cerebral mechanisms involved in pain regulation. The descending pain inhibitory circuitry is a well defined cerebral network that enables regulation of afferent nociceptive information. The aim of this thesis was to investigate different aspects of pain modulation in patients with Fibromyalgia (FM) as well as the impact of specific genetic variations on pain sensitivity dynamics in healthy subjects. Study I demonstrated that patients with FM had an impaired mechanism for descending pain inhibition and that this deficiency was paired with a diminished activation of the rostral anterior cingulate cortex and the brainstem, two regions that play an important role in descending pain regulation. These results advance the understanding of the pathophysiology in FM and provide new directions for the development of effective treatments. Study II investigated the possible impact of negative mood on pain processing in patients with FM and found that brain activity during experimental pain was not modulated by depressive symptoms, anxiety, or catastrophizing thoughts. The activity of the brain regions previously implicated in the pathophysiology of FM were not correlated with high ratings of negative mood which suggests that there are two segregated cerebral mechanisms dealing with pain and negative mood in FM. In study III patients with FM were treated with a Noradrenaline-Serotonin Reuptake Inhibitor (milnacipran) or placebo for 12 weeks. All patients that reported an improvement of symptoms after treatment, including both milnacipran and placebo responders, were compared and results revealed that sensitivity to pressure improved selectively in milnacipran responders. This decreased sensitivity also correlated to the improvement of ongoing clinical pain. The study suggests that the specific effect of milnacipran acts through direct antinociceptive effects and/or by the strengthening of the endogenous pain inhibitory mechanisms. In study IV the genetic influence on the descending pain inhibitory function in healthy subjects was assessed. Results demonstrate that a genetic polymorphism (COMTval158met) with influence on the function of the noradrenergic and dopaminergic systems, is related to the response dynamics of repeated pain stimulations following opioid administration. Results suggest that the initial pain response is not influenced by the COMTval158met polymorphism but when the system is challenged the difference is expressed.
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- Jensen, Karin B, et al.
(author)
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Evidence of dysfunctional pain inhibition in Fibromyalgia reflected in rACC during provoked pain.
- 2009
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In: Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0304-3959 .- 1872-6623. ; 144:1-2, s. 95-100
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Journal article (peer-reviewed)abstract
- Over the years, many have viewed Fibromyalgia syndrome (FMS) as a so-called "functional disorder" and patients have experienced a concomitant lack of interest and legitimacy from the medical profession. The symptoms have not been explained by peripheral mechanisms alone nor by specific central nervous system mechanisms. In this study, we objectively evaluated the cerebral response to individually calibrated pain provocations of a pain-free body region (thumbnail). The study comprised 16 female FMS patients and 16 individually age-matched controls. Brain activity was measured using functional magnetic resonance imaging (fMRI) during individually calibrated painful pressures representing 50 mm on a visual analogue scale (VAS) ranging from 0 to 100 mm. Patients exhibited higher sensitivity to pain provocation than controls as they required less pressure to evoke equal pain magnitudes (U(A)=48, p<.002). Despite lower pressures applied in patients at VAS 50 mm, the fMRI-analysis revealed no difference in activity in brain regions relating to attention and affect or regions with sensory projections from the stimulated body area. However, in the primary link in the descending pain regulating system (the rostral anterior cingulate cortex) the patients failed to respond to pain provocation. The attenuated response to pain in this brain region is the first demonstration of a specific brain region where the impairment of pain inhibition in FMS patients is expressed. These results validate previous reports of dysfunctional endogenous pain inhibition in FMS and advance the understanding of the central pathophysiologic mechanisms, providing a new direction for the development of successful treatments in FMS.
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- Jensen, Karin B, et al.
(author)
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Increased sensitivity to thermal pain following a single opiate dose is influenced by the COMT val(158)met polymorphism.
- 2009
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 4:6
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Journal article (peer-reviewed)abstract
- Increased pain sensitivity after opioid administration (opioid-induced hyperalgesia) and/or repeated painful stimuli is an individually varying and clinically important phenomenon. The functional polymorphism (val(158)met) of the Catechol-O-methyltransferase (COMT) gene regulates the metabolism of dopamine/noradrenaline. Individuals homozygous for the met(158) allele have been reported to have increased pain sensitivity and there are findings of lower micro-opioid system activation during sustained pain. We hypothesized that met/met individuals would exhibit higher pain sensitization and opioid-induced hyperalgesia in response to repeated pain stimuli and an intravenous injection of an opioid drug. Participants were 43 healthy subjects who went through an experiment where five blocks of pain were induced to the hand using a heat probe. After each stimulus subjects rated the pain on a visual analogue scale (VAS) from 0 mm (no pain) to 100 mm (worst possible pain). Before the second stimulus there was an intravenous injection of a rapid and potent opioid drug. At baseline there was no difference in pain ratings between the COMTval(158)met genotypes, F(2, 39)<1. However, a repeated measures ANOVA for all five stimuli revealed a main effect for COMTval(158)met genotype, F(2, 36) = 4.17, p = 0.024. Met/met individuals reported significantly more pain compared to val/val, p = 0.010. A pairwise comparison of baseline and the opioid intervention demonstrated that analgesia was induced in all groups (p = 0.042) without a separating effect for genotype (n.s). We suggest that the initial response of the descending pain system is not influenced by the COMTval(158)met polymorphism but when the system is challenged the difference is revealed. An important clinical implication of this may be that the COMTval(158)met related differences may be more expressed in individuals where the inhibitory system is already challenged and sensitive, e.g. chronic pain patients. This has to be proven in future studies where the impact of the COMTval(158)met polymorphism on opioid treatment in patients is addressed.
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- Jensen, Richard A., et al.
(author)
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Multiple factors affect the loss of measurable C-peptide over 6 years in newly diagnosed 15- to 35-year-old diabetic subjects
- 2007
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In: Journal of diabetes and its complications. - : Elsevier BV. - 1056-8727 .- 1873-460X. ; 21:4, s. 205-213
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Journal article (peer-reviewed)abstract
- Objective: The aim of this study is to identify risk factors for the loss of measurable plasma C-peptide in newly diagnosed 15- to 35-year-old diabetic subjects. Methods: This Swedish study included 778 subjects. C-peptide levels were obtained each year for 6 years after diagnosis. Loss of measurable C-peptide was defined as a level at or below the lower detection limit of the local assay (0.13 nmol/l). In addition to C-peptide, other baseline covariates included gender, age, body mass index, HLA genotype, and autoantibody levels. Results: Compared with autoantibody-negative subjects, autoantibody-positive subjects had lower median baseline C-peptide (0.27 vs. 0.50, P<001), their levels declined over the study period, and the risk of losing measurable C-peptide was significantly higher when more than one autoantibody was present [odds ratio (OR), 4.0; 95% confidence interval (CI), 2.13-7.54]. Among autoantibody-positive individuals, the presence of GAD65Ab (OR, 1.8; 95% Cl, 1.24-2.51) and islet cell antibodies (OR, 1.6; 95% CI, 1.19-2.18) conferred a higher risk for loss of measurable C-peptide as did female gender (OR, 1.6; 95% CI, 1.17-2.11) and time after diagnosis (OR, 1.5 for each additional year postdiagnosis; 95% CI, 1.41-1.57). Higher baseline C-peptide levels were protective (OR, 0.5 for each additional log nanomoles per liter; 95% CI, 0.36-0.58). Conclusions: This study identified autoantibody status, gender, and baseline C-peptide levels as factors that will be useful for predicting the disease course of 15- to 35-year-old diabetic individuals.
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| 10. |
- Kosek, Eva, et al.
(author)
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Genetic variation in the serotonin transporter gene (5-HTTLPR, rs25531) influences the analgesic response to the short acting opioid Remifentanil in humans.
- 2009
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In: Molecular Pain. - : SAGE Publications. - 1744-8069. ; 5
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Journal article (peer-reviewed)abstract
- BACKGROUND: There is evidence from animal studies that serotonin (5-HT) can influence the antinociceptive effects of opioids at the spinal cord level. Therefore, there could be an influence of genetic polymorphisms in the serotonin system on individual variability in response to opioid treatment of pain. The serotonin transporter (5-HTT) is a key regulator of serotonin metabolism and availability and its gene harbors several known polymorphisms that are known to affect 5-HTT expression (e.g. 5-HTTLPR, rs25531). The aim of this study was to investigate if the triallelic 5-HTTLPR influences pain sensitivity or the analgesic effect of opioids in humans. 43 healthy volunteers (12 men, 31 women, mean age 26 years) underwent heat pain stimulations before and after intravenous injection of Remifentanil; a rapid and potent opioid drug acting on micro-type receptors. Subjects rated their perceived pain on a visual analogue scale (VAS). All participants were genotyped for the 5-HTTLPR and the rs25531 polymorphism. We recruited by advertising, with no history of drug abuse, chronic pain or psychiatric disorders.RESULTS: At baseline, there was no difference in pain ratings for the different triallelic 5-HTTLPR genotype groups. However, the opiod drug had a differential analgesic effect depending on the triallelic 5-HTTLPR genotype. Remifentanil had a significantly better analgesic effect in individuals with a genotype coding for low 5-HTT expression (SA/SA and SA/LG) as compared to those with high expression(LA/LA), p < 0.02. The analgesic effect for the three different genotype groups was linear to degree of 5-HTT expression.CONCLUSION: This is the first report showing an influence of the triallelic 5-HTTLPR on pain sensitivity or the analgesic effect of opioids in humans. Previously the 5-HTTLPR s-allele has been associated with higher risk of developing chronic pain conditions but in this study we show that the genotype coding for low 5-HTT expression is associated with a better analgesic effect of an opioid. The s-allele has been associated with downregulation of 5-HT1 receptors and we suggest that individuals with a desensitization of 5-HT1 receptors have an increased analgesic response to opioids during acute pain stimuli, but may still be at increased risk of developing chronic pain conditions.
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