| 1. |
- Bresell, Anders, et al.
(författare)
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Bioinformatic and enzymatic characterization of the MAPEG superfamily
- 2005
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Ingår i: The FEBS Journal. - : Wiley. - 1742-464X .- 1742-4658. ; 272:7, s. 1688-1703
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Tidskriftsartikel (refereegranskat)abstract
- The membrane associated proteins in eicosanoid and glutathione metabolism (MAPEG) superfamily includes structurally related membrane proteins with diverse functions of widespread origin. A total of 136 proteins belonging to the MAPEG superfamily were found in database and genome screenings. The members were found in prokaryotes and eukaryotes, but not in any archaeal organism. Multiple sequence alignments and calculations of evolutionary trees revealed a clear subdivision of the eukaryotic MAPEG members, corresponding to the six families of microsomal glutathione transferases (MGST) 1, 2 and 3, leukotriene C4 synthase (LTC4), 5-lipoxygenase activating protein (FLAP), and prostaglandin E synthase. Prokaryotes contain at least two distinct potential ancestral subfamilies, of which one is unique, whereas the other most closely resembles enzymes that belong to the MGST2/FLAP/LTC4 synthase families. The insect members are most similar to MGST1/prostaglandin E synthase. With the new data available, we observe that fish enzymes are present in all six families, showing an early origin for MAPEG family differentiation. Thus, the evolutionary origins and relationships of the MAPEG superfamily can be defined, including distinct sequence patterns characteristic for each of the subfamilies. We have further investigated and functionally characterized representative gene products from Escherichia coli, Synechocystis sp., Arabidopsis thaliana and Drosophila melanogaster, and the fish liver enzyme, purified from pike (Esox lucius). Protein overexpression and enzyme activity analysis demonstrated that all proteins catalyzed the conjugation of 1-chloro-2,4-dinitrobenzene with reduced glutathione. The E. coli protein displayed glutathione transferase activity of 0.11 µmol·min−1·mg−1 in the membrane fraction from bacteria overexpressing the protein. Partial purification of the Synechocystis sp. protein yielded an enzyme of the expected molecular mass and an N-terminal amino acid sequence that was at least 50% pure, with a specific activity towards 1-chloro-2,4-dinitrobenzene of 11 µmol·min−1·mg−1. Yeast microsomes expressing the Arabidopsis enzyme showed an activity of 0.02 µmol·min−1·mg−1, whereas the Drosophila enzyme expressed in E. coli was highly active at 3.6 µmol·min−1·mg−1. The purified pike enzyme is the most active MGST described so far with a specific activity of 285 µmol·min−1·mg−1. Drosophila and pike enzymes also displayed glutathione peroxidase activity towards cumene hydroperoxide (0.4 and 2.2 µmol·min−1·mg−1, respectively). Glutathione transferase activity can thus be regarded as a common denominator for a majority of MAPEG members throughout the kingdoms of life whereas glutathione peroxidase activity occurs in representatives from the MGST1, 2 and 3 and PGES subfamilies.
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| 2. |
- Olofsson, Martin, 1980-, et al.
(författare)
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Eyespot display in the peacock butterfly triggers antipredator behaviors in naive adult fowl
- 2013
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 24:1, s. 305-310
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Tidskriftsartikel (refereegranskat)abstract
- Large conspicuous eyespots have evolved in multiple taxa and presumably function to thwart predator attacks. Traditionally, large eyespots were thought to discourage predator attacks because they mimicked eyes of the predators' own predators. However, this idea is controversial and the intimidating properties of eyespots have recently been suggested to Amply be a consequence of their conspicuousness. Some lepidopteran species include large eyespots in their antipredation repertoire. In the peacock butterfly, Mathis io, eyespots are typically hidden during rest and suddenly exposed by the butterfly when disturbed. Previous experiments have shown that small wild passerines are intimidated by this display. Here, we test whether eyespots also intimidate a considerably larger bird, domestic fowl, Gallus gallus domesticus, by staging interactions between birds and peacock butterflies that were sham-painted or had their eyespots painted oven Our results show that birds typically fled when peacock butterflies performed their display regardless of whether eyespots were visible or painted over. However, birds confronting butterflies with visible eyespots delayed their return to the butterfly, were more vigilant, and more likely to utter alarm calls associated with detection of ground-based predators, compared with birds confronting butterflies with eyespots painted over. Because production of alarm calls and increased vigilance are antipredation behaviors in the fowl, their reaction suggests that eyespots may elicit fear rather than just an aversion to conspicuous patterns. Our results, therefore, suggest that predators perceive large lepidopteran eyespots as belonging to the eyes of a potential predator.
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| 3. |
- Persson, Anna, et al.
(författare)
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Heart Rate Variability for Classification of Alert Versus Sleep Deprived Drivers in Real Road Driving Conditions
- 2021
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Ingår i: IEEE transactions on intelligent transportation systems (Print). - : IEEE. - 1524-9050 .- 1558-0016. ; 22:6, s. 3316-3325
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Tidskriftsartikel (refereegranskat)abstract
- Driver sleepiness is a contributing factor in many road fatalities. A long-standing goal in driver state research has therefore been to develop a robust sleepiness detection system. It has been suggested that various heart rate variability (HRV) metrics can be used for driver sleepiness classification. However, since heart rate is modulated not only by sleepiness but also by several other time-varying intra-individual factors such as posture, distress, boredom and relaxation, it is relevant to highlight not only the possibilities but also the difficulties involved in HRV-based driver sleepiness classification. This paper investigates the reliability of HRV as a standalone feature for driver sleepiness detection in a realistic setting. Data from three real-road driving studies were used, including 86 drivers in both alert and sleep-deprived conditions. Subjective ratings based on the Karolinska sleepiness scale (KSS) were used as ground truth when training four binary classifiers (k-nearest neighbours, support vector machine, AdaBoost, and random forest). The best performance was achieved with the random forest classifier with an accuracy of 85%. However, the accuracy dropped to 64% for three-class classification and to 44% for subject-independent, leave-one-participant-out classification. The worst results were obtained in the severely sleepy class. The results show that in realistic driving conditions, subject-independent sleepiness classification based on HRV is poor. The conclusion is that more work is needed to control for the many confounding factors that also influence HRV before it can be used as input to a driver sleepiness detection system.
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| 4. |
- Persson, Anna, et al.
(författare)
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Heart Rate Variability for Driver Sleepiness Classification in Real Road Driving Conditions
- 2019
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - : IEEE. - 9781538613115 - 9781538613122 ; , s. 6537-6540
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Konferensbidrag (refereegranskat)abstract
- Approximately 20-30% of all road fatalities are related to driver sleepiness. A long-lasting goal in driver state research has therefore been to develop a robust sleepiness detection system. Since the alertness level is reflected in autonomous nervous system activity, it has been suggested that various heart rate variability (HRV) metrics can be used as features for driver sleepiness classification. Since the heart rate is modulated by many different factors, and not just by sleepiness, it is relevant to question the high driver sleepiness classification accuracies that have occasionally been presented in the literature. The main objective of this paper is thus to test how well a sleepiness classification system based on HRV features really is. A unique data set with 86 drivers, obtained while driving on real roads in real traffic, both in alert and sleep deprived conditions, was used to train and test a support vector machine (SVM) classifier. Subjective ratings based on the Karolinska sleepiness scale (KSS) was used as ground truth to divide the data into three classes (alert, somewhat sleepy and severely sleepy). Even though nearly all the 24 investigated HRV metrics showed significant differences between sleepiness levels, the SVM results only reached a mean accuracy of 61 %, with the worst results originating from the severely sleepy cases. In summary, the high classification performance that may arise in studies with high experimental control could not be replicated under realistic driving conditions. Future works should focus on how various confounding factors should be accounted for when using HRV based metrics as input to a driver sleepiness detection system.
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| 5. |
- Rattfält, Linda, 1979-, et al.
(författare)
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A Canonical correlation approach to heart beat detection in textile ECG measurements
- 2006
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Ingår i: IET 3rd International Conference On Advances in Medical, Signal and Information Processing, 2006. MEDSIP 2006. - : IEEE. - 0863416586 - 9780863416583 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- Research in textile sensors has lead to new ways to measure electrocardiograms (ECG). However, additional disturbances from e.g. muscular noise and high skin-electrode impedances often result in poor signal quality. The paper contains a simple application of canonical correlation analysis (CCA) on multi channel ECG signals recorded with textile electrodes. Using CCA to solve the blind source separation (BSS) problem, we intend to separate the ECG signal from the various noise sources. The method (CCABSS) was compared to simple averaging of the ECG channels and to the independent component analysis method (ICA). A heart beat detector was used to evaluate the signal quality. Results show that the signal was completely lost while simulating various noise in 33%, 17% and 7% of the cases for averaging, ICA and CCA, respectively.
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| 6. |
- Sköld, Carl Magnus, et al.
(författare)
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A retrospective chart review of pirfenidone-treated patients in Sweden : the REPRIS study
- 2016
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Ingår i: EUROPEAN CLINICAL RESPIRATORY JOURNAL. - Järfälla : Informa UK Limited. - 2001-8525. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease that usually results in respiratory failure and death. Pirfenidone was approved as the first licensed therapy for IPF in Europe based on phase III trials where patients with a forced vital capacity (FVC) >50% of predicted were included. The aim of this study was to characterise patients treated with pirfenidone in Swedish clinical practice and to describe the adherence to the reimbursement restriction since reimbursement was only applied for patients with FVC below 80% of predicted. Methods: This was a retrospective, observational chart review of IPF patients treated with pirfenidone from three Swedish university clinics. Patients initiated on treatment during the period 28 June 2012 to 20 November 2014 were included. Data on patient characteristics, basis of diagnosis, treatment duration, quality of life, and adverse drug reactions (ADRs) were collected from medical charts. Results: Forty-four patients were screened and 33 were included in the study. The mean treatment duration from start of pirfenidone until discontinuation or end of study was 38 weeks. At the initiation of pirfenidone treatment, FVC was 62.7% (12.1) [mean (SD)], diffusion capacity (DLco) was 45.1% (13.8) of predicted, and the ratio of forced expiratory volume on 1 sec (FEV1) to FVC was 0.78 (0.1). The percentage of patients with an FVC between 50 and 80% was 87%. Ten of the patients had ADRs including gastrointestinal and skin-related events, cough and signs of impaired hepatic function, but this led to treatment discontinuation in only two patients. Conclusion: Data from this chart review showed that adherence to the Swedish reimbursement restriction was followed in the majority of patients during the study period. At the start of pirfenidone treatment, lung function, measured as FVC, was lower in the present cohort of Swedish IPF patients compared with other registry and real-life data. About a third of the patients had ADRs, but discontinuation of the treatment because of ADRs was relatively uncommon.
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| 7. |
- Thulin, Helena, et al.
(författare)
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Defecation disturbances after cystectomy for urinary bladder cancer
- 2011
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Ingår i: BJU International. - : Blackwell Publishing Ltd. - 1464-4096 .- 1464-410X. ; 108:2, s. 196-203
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Tidskriftsartikel (refereegranskat)abstract
- What’s known on the subject? and What does the study add?Functional gastrointestinal symptoms and problems are common after radical cystectomy with urinary diversion. This study adds new important epidemiological data on this group of symptoms. OBJECTIVE: To describe and compare long-term defecation disturbances in patients who had undergone a cystectomy due to urinary bladder cancer with non-continent urostomies, continent reservoirs and orthotopic neobladder urinary diversions. PATIENTS AND METHODS: During their follow-up we attempted to contact all men and women aged 30–80 years who had undergone cystectomy and urinary diversion at seven Swedish hospitals. During a qualitative phase we identified defecation disturbances as a distressful symptom and included this item in a study-specific questionnaire together with free-hand comments. The patients completed the questionnaire at home. Outcome variables were dichotomized and the results are presented as relative risks with 95% confidence interval. RESULTS: The questionnaire was returned from 452 (92%) of 491 identified patients. Up to 30% reported problems with the physiological emptying process of stool (bowel movement, sensory rectal function, awareness of need for defecation, motoric rectal and anal function, straining ability). A sense of decreased straining capacity was reported by 20% of the men and women with non-continent urostomy and 14% and 8% of those with continent reservoirs and orthotopic neobladders, respectively. CONCLUSIONS: Of the cystectomized individuals 30% reported problems with the physiological emptying process of stool (bowel movement, sensory rectal function, awareness of need for defecation, motoric rectal and anal function, straining ability). Those wanting to improve the situation for bladder cancer survivors may consider communicating before surgery the possibility of stool-emptying problems, and asking about them after surgery.
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