| 21. |
- Khan, Omar M., 1980, et al.
(author)
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Geranylgeranyltransferase type I (GGTase-I) deficiency hyperactivates macrophages and induces erosive arthritis in mice.
- 2011
-
In: The Journal of clinical investigation. - 1558-8238. ; 121:2, s. 628-39
-
Journal article (peer-reviewed)abstract
- RHO family proteins are important for the function of inflammatory cells. They are modified with a 20-carbon geranylgeranyl lipid in a process catalyzed by protein geranylgeranyltransferase type I (GGTase-I). Geranylgeranylation is viewed as essential for the membrane targeting and activity of RHO proteins. Consequently, inhibiting GGTase-I to interfere with RHO protein activity has been proposed as a strategy to treat inflammatory disorders. However, here we show that mice lacking GGTase-I in macrophages develop severe joint inflammation resembling erosive rheumatoid arthritis. The disease was initiated by the GGTase-I-deficient macrophages and was transplantable and reversible in bone marrow transplantation experiments. The cells accumulated high levels of active GTP-bound RAC1, CDC42, and RHOA, and RAC1 remained associated with the plasma membrane. Moreover, GGTase-I deficiency activated p38 and NF-κB and increased the production of proinflammatory cytokines. The results challenge the view that geranylgeranylation is essential for the activity and localization of RHO family proteins and suggest that reduced geranylgeranylation in macrophages can initiate erosive arthritis.
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| 22. |
- Khan, Samiullah, et al.
(author)
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Aglycone specificity of Thermotoga neapolitana beta-glucosidase 1A modified by mutagenesis, leading to increased catalytic efficiency in quercetin-3-glucoside hydrolysis
- 2011
-
In: BMC Biochemistry. - : Springer Science and Business Media LLC. - 1471-2091. ; 12
-
Journal article (peer-reviewed)abstract
- Background: The thermostable beta-glucosidase (TnBgl1A) from Thermotoga neapolitana is a promising biocatalyst for hydrolysis of glucosylated flavonoids and can be coupled to extraction methods using pressurized hot water. Hydrolysis has however been shown to be dependent on the position of the glucosylation on the flavonoid, and e. g. quercetin-3-glucoside (Q3) was hydrolysed slowly. A set of mutants of TnBgl1A were thus created to analyse the influence on the kinetic parameters using the model substrate para-nitrophenyl-beta-D-glucopyranoside (pNPGlc), and screened for hydrolysis of Q3. Results: Structural analysis pinpointed an area in the active site pocket with non-conserved residues between specificity groups in glycoside hydrolase family 1 (GH1). Three residues in this area located on beta-strand 5 (F219, N221, and G222) close to sugar binding sub-site +2 were selected for mutagenesis and amplified in a protocol that introduced a few spontaneous mutations. Eight mutants (four triple: F219L/P165L/M278I, N221S/P165L/M278I, G222Q/P165L/M278I, G222Q/V203M/K214R, two double: F219L/K214R, N221S/P342L and two single: G222M and N221S) were produced in E. coli, and purified to apparent homogeneity. Thermostability, measured as T-m by differential scanning calorimetry (101.9 degrees C for wt), was kept in the mutated variants and significant decrease (Delta T of 5 -10 degrees C) was only observed for the triple mutants. The exchanged residue(s) in the respective mutant resulted in variations in K-M and turnover. The K-M-value was only changed in variants mutated at position 221 (N221S) and was in all cases monitored as a 2-3 x increase for pNPGlc, while the K-M decreased a corresponding extent for Q3. Turnover was only significantly changed using pNPGlc, and was decreased 2-3 x in variants mutated at position 222, while the single, double and triple mutated variants carrying a mutation at position 221 (N221S) increased turnover up to 3.5 x compared to the wild type. Modelling showed that the mutation at position 221, may alter the position of N291 resulting in increased hydrogen bonding of Q3 (at a position corresponding to the +1 subsite) which may explain the decrease in K-M for this substrate. Conclusion: These results show that residues at the +2 subsite are interesting targets for mutagenesis and mutations at these positions can directly or indirectly affect both K-M and turnover. An affinity change, leading to a decreased K-M, can be explained by an altered position of N291, while the changes in turnover are more difficult to explain and may be the result of smaller conformational changes in the active site.
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| 23. |
- Khan, Sami, et al.
(author)
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Immobilization of thermostable beta-glucosidase variants on acrylic supports for biocatalytic processes in hot water
- 2012
-
In: Journal of Molecular Catalysis B: Enzymatic. - : Elsevier BV. - 1873-3158 .- 1381-1177. ; 80, s. 28-38
-
Journal article (peer-reviewed)abstract
- Two variants of the thermostable beta-glucosidase TnBgl1A (wt and N221S/P342L) from Thermotoga neapolitana were immobilized on acrylic supports (Eupergit (R) C, Eupergit (R) C250L, and cryogel) and evaluated at conditions close to the boiling point of water. Thermo-gravimetric analysis showed the supports to be stable <250 degrees C. Both wt and N221S/P342L were covalently bound to oxirane-groups respectively via glutaraldehyde spacers, and for coupling reactions 26 Lys and 20 Ser/Thr were surface-located. Immobilized enzymes were active on all supports in the temperature range 80-95 degrees C, but the observed specific activity was low (<= 19 U mg(-1)) using the cryogel. More than 91% of the initial activity was maintained after ten times recycling, and the same was recovered after 3 months storage at 4 degrees C for Eupergit (R) supports by simply incubating the preparation with bovine serum albumin. No storage loss was detectable on cryogels. The glutaraldehyde spacer improved activity on cryogels, but not on Eupergie supports. Immobilization on Eupergit (R) C250L yielded the highest observed specific activity (254 U mg(-1) for N221S/P342L) in a procedure including blocking of free oxirane-groups by BSA. This biocatalyst was used for on-line hydrolysis of quercetin-glucosides in a yellow onion extract at 80 degrees C, proving the immobilized biocatalyst to be promising in on-line systems for extraction and hydrolysis using hot pressurized water. (C) 2012 Elsevier B.V. All rights reserved.
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| 24. |
- Kiiski, Johanna I., et al.
(author)
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FANCM mutation c.5791C>T is a risk factor for triple-negative breast cancer in the Finnish population
- 2017
-
In: Breast Cancer Research and Treatment. - : Springer Science and Business Media LLC. - 0167-6806 .- 1573-7217. ; 166:1, s. 217-226
-
Journal article (peer-reviewed)abstract
- Purpose: The FANCM c.5101C>T nonsense mutation was previously found to associate with breast cancer in the Finnish population, especially among triple-negative cases. Here, we studied the prevalence of three other FANCM variants: c.5791C>T, which has been reported to predispose to familial breast cancer, and the c.4025_4026delCT and c.5293dupA variants recently identified in Finnish cancer patients. Methods: We genotyped the FANCM c.5791C>T mutation in 4806 invasive breast cancer patients, including BRCA1/2 mutation negative familial cases and unselected cases, and in 2734 healthy population controls from four different geographical areas of Finland. The association of the mutation with breast cancer risk among patient subgroups was statistically evaluated. We further analyzed the combined risk associated with c.5101C>T and c.5791C>T mutations. We also genotyped 526 unselected ovarian cancer patients for the c.5791C>T mutation and 862 familial breast cancer patients for the c.4025_4026delCT and c.5293dupA variants. Results: The frequency of the FANCM c.5791C>T mutation was higher among breast cancer cases than in controls (OR 1.94, 95% CI 0.87–4.32, P = 0.11), with a statistically significant association with triple-negative breast cancer (OR 5.14, 95% CI 1.65–16.0, P = 0.005). The combined analysis for c.5101C>T and c.5791C>T carriers confirmed a strong association with breast cancer (OR 1.86, 95% CI 1.32–2.49, P = 0.0002), especially among the triple-negative patients (OR 3.08, 95% CI 1.77–5.35, P = 0.00007). For the other variants, only one additional c.4025_4026delCT carrier and no c.5293dupA carriers were observed. Conclusions: These results support the role of FANCM as a breast cancer susceptibility gene, particularly for triple-negative breast cancer.
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| 25. |
- Kulkarni, Tejas, et al.
(author)
-
Crystal structure of β-glucosidase 1A from Thermotoga neapolitana and comparison of active site mutants for hydrolysis of flavonoid glucosides
- 2017
-
In: Proteins: Structure, Function and Bioinformatics. - : Wiley. - 1097-0134 .- 0887-3585. ; 85:5, s. 872-884
-
Journal article (peer-reviewed)abstract
- The β-glucosidase TnBgl1A catalyses hydrolysis of O-linked terminal β-glycosidic bonds at the nonreducing end of glycosides/oligosaccharides. Enzymes with this specificity have potential in lignocellulose conversion (degrading cellobiose to glucose) and conversion of bioactive flavonoids (modification of glycosylation results in modulation of bioavailability). Previous work has shown TnBgl1A to hydrolyse 3, 4′ and 7 glucosylation in flavonoids, and although conversion of 3-glucosylated substrate to aglycone was low, it was improved by mutagenesis of residue N220. To further explore structure-function relationships, the crystal structure of the nucleophile mutant TnBgl1A-E349G was determined at 1.9 Å resolution, and docking studies of flavonoid substrates were made to reveal substrate interacting residues. A series of single amino acid changes were introduced in the aglycone binding region [N220(S/F), N221(S/F), F224(I), F310(L/E), and W322(A)] of the wild type. Activity screening was made on eight glucosylated flavonoids, and kinetic parameters were monitored for the flavonoid quercetin-3-glucoside (Q3), as well as for the model substrate para-nitrophenyl-β-d-glucopyranoside (pNPGlc). Substitution by Ser at N220 or N221 increased the catalytic efficiency on both pNPGlc and Q3. Residue W322 was proven important for substrate accomodation, as mutagenesis to W322A resulted in a large reduction of hydrolytic activity on 3-glucosylated flavonoids. Flavonoid glucoside hydrolysis was unaffected by mutations at positions 224 and 310. The mutations did not significantly affect thermal stability, and the variants kept an apparent unfolding temperature of 101°C. This work pinpoints positions in the aglycone region of TnBgl1A of importance for specificity on flavonoid-3-glucosides, improving the molecular understanding of activity in GH1 enzymes.
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| 26. |
- Kälvemark Sporrong, Sofia, et al.
(author)
-
Developing and sustaining human resources in the health supply chain in Ethiopia : barriers and enablers.
- 2016
-
In: Rural and remote health. - 1445-6354. ; 16:3, s. 3613-
-
Journal article (peer-reviewed)abstract
- INTRODUCTION: The health supply chain is often the weakest link in achieving the health-related Millennium Development Goals and universal health coverage, requiring trained professionals who are often unavailable. In Ethiopia there have been recent developments in the area of health supply chain management. The aim of this study was to explore the current status of the development of human resources in health supply chain management in Ethiopia and to identify important factors affecting this development.METHODS: A series of face-to-face interviews with key stakeholders was carried out in 2014. The interviews were conducted using a semi-structured interview guide. The interview guide comprised 51 questions. A qualitative analysis of transcripts was made.RESULTS: A total of 25 interviews were conducted. Three themes were identified: General changes: recognition, commitment and resources, Education and training, and Barriers and enablers. Results confirm the development of human resources in health supply chain management in many areas. However, several problems were identified including lack of coordination, partly due to the large number of stakeholders; reported high staff mobility; and a lack of overall strategy regarding the job/career structures necessary for maintaining human resources. Rural areas have a particular set of problems, including in transportation of goods and personnel, attracting and keeping personnel, and in communication and access to information.CONCLUSIONS: Ethiopia is on the way to developing a nationwide viable system for health supply chain management. However, there are still challenges. Short-term challenges include the importance of highlighting strategies and programs for human resources in health supply chain management. In the long term, commitments to financial support must be obtained. A strategy is needed for the further development and sustainability of human resources in the health supply chain in Ethiopia.
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| 27. |
- Lawrenson, Kate, et al.
(author)
-
Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus
- 2016
-
In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
-
Journal article (peer-reviewed)abstract
- A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk.
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| 28. |
- Lindahl, Sofia, et al.
(author)
-
An on-line method for pressurized hot water extraction and enzymatic hydrolysis of quercetin glucosides from onions.
- 2013
-
In: Analytica Chimica Acta. - : Elsevier BV. - 1873-4324 .- 0003-2670. ; 785, s. 50-59
-
Journal article (peer-reviewed)abstract
- A novel environmentally sound continuous-flow hot water extraction and enzymatic hydrolysis method for determination of quercetin in onion raw materials was successfully constructed using a stepwise optimization approach. In the first step, enzymatic hydrolysis of quercetin-3,4'-diglucoside to quercetin was optimized using a three level central composite design considering temperature (75-95°C), pH (3-6) and volume concentration of ethanol (5-15%). The enzyme used was a thermostable β-glucosidase variant (termed TnBgl1A_N221S/P342L) covalently immobilized on either of two acrylic support-materials (Eupergit(®) C 250L or monolithic cryogel). Optimal reaction conditions were irrespective of support 84°C, 5% ethanol and pH 5.5, and at these conditions, no significant loss of enzyme activity was observed during 72h of use. In a second step, hot water extractions from chopped yellow onions, run at the optimal temperature for hydrolysis, were optimized in a two level design with respect to pH (2.6 and 5.5), ethanol concentration (0 and 5%) and flow rate (1 and 3mLmin(-1)) Obtained results showed that the total quercetin extraction yield was 1.7 times higher using a flow rate of 3mLmin(-1) (extraction time 90min), compared to a flow rate of 1mLmin(-1) (extraction time 240min). Presence of 5% ethanol was favorable for the extraction yield, while a further decrease in pH was not, not even for the extraction step alone. Finally, the complete continuous flow method (84°C, 5% ethanol, pH 5.5, 3mLmin(-1)) was used to extract quercetin from yellow, red and shallot onions and resulted in higher or similar yield (e.g. 8.4±0.7μmolg(-1) fresh weight yellow onion) compared to a conventional batch extraction method using methanol as extraction solvent.
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| 29. |
- Markelius, Alva, et al.
(author)
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Differential Outcomes Training of Visuospatial Memory: A Gamified Approach Using a Socially Assistive Robot
- 2024
-
In: INTERNATIONAL JOURNAL OF SOCIAL ROBOTICS. - : Springer Science and Business Media B.V.. - 1875-4791 .- 1875-4805. ; 16:2, s. 363-384
-
Journal article (peer-reviewed)abstract
- This study represents the first stage of evaluating whether cognitive training interventions may be facilitated by the presence of a socially assistive robot (SAR) and gamification. Our experimental setup involves using a SAR providing feedback to a gamified visuospatial working memory task, administered according to a differential outcomes training (DOT) protocol. The study's main objective was to investigate whether performance and attitude towards the task would be affected by different robotic setups (none, simulated or physical) and in relation to different challenge levels. We measured performance accuracy on the gamified visuospatial memory task and self-reported affective ratings, which are relevant for assessing attitude towards the task and providing indicators to the potential for using a SAR for a longer-term cognitive intervention. Additionally, we conducted exploratory analyses of eye movement strategies for memory encoding during the task. The results demonstrated a significant differential outcomes effect (DOE) on memory performance accuracy, regardless of Robot type and Challenge level, providing evidence that a DOE can still be obtained when a SAR interacts with participants. Moreover, the results from the affective ratings revealed that participants accompanied by the physical robot reported lower levels of stress and increased levels of control. Our results demonstrate, for the first time, a DOE using a SAR in a gamified context. This result, coupled with positive subjective reporting of the human-robot interactive experience of participants, demonstrates the potential for using a SAR to: (i) promote positive attitudes for a DOT-based cognitive intervention, without (ii) negatively affecting task performance.
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| 30. |
- Marto, João Pedro, et al.
(author)
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Safety and Outcome of Revascularization Treatment in Patients With Acute Ischemic Stroke and COVID-19: The Global COVID-19 Stroke Registry.
- 2023
-
In: Neurology. - 1526-632X. ; 100:7
-
Journal article (peer-reviewed)abstract
- COVID-19-related inflammation, endothelial dysfunction, and coagulopathy may increase the bleeding risk and lower the efficacy of revascularization treatments in patients with acute ischemic stroke (AIS). We aimed to evaluate the safety and outcomes of revascularization treatments in patients with AIS and COVID-19.This was a retrospective multicenter cohort study of consecutive patients with AIS receiving intravenous thrombolysis (IVT) and/or endovascular treatment (EVT) between March 2020 and June 2021 tested for severe acute respiratory syndrome coronavirus 2 infection. With a doubly robust model combining propensity score weighting and multivariate regression, we studied the association of COVID-19 with intracranial bleeding complications and clinical outcomes. Subgroup analyses were performed according to treatment groups (IVT-only and EVT).Of a total of 15,128 included patients from 105 centers, 853 (5.6%) were diagnosed with COVID-19; of those, 5,848 (38.7%) patients received IVT-only and 9,280 (61.3%) EVT (with or without IVT). Patients with COVID-19 had a higher rate of symptomatic intracerebral hemorrhage (SICH) (adjusted OR 1.53; 95% CI 1.16-2.01), symptomatic subarachnoid hemorrhage (SSAH) (OR 1.80; 95% CI 1.20-2.69), SICH and/or SSAH combined (OR 1.56; 95% CI 1.23-1.99), 24-hour mortality (OR 2.47; 95% CI 1.58-3.86), and 3-month mortality (OR 1.88; 95% CI 1.52-2.33). Patients with COVID-19 also had an unfavorable shift in the distribution of the modified Rankin score at 3 months (OR 1.42; 95% CI 1.26-1.60).Patients with AIS and COVID-19 showed higher rates of intracranial bleeding complications and worse clinical outcomes after revascularization treatments than contemporaneous non-COVID-19 patients receiving treatment. Current available data do not allow direct conclusions to be drawn on the effectiveness of revascularization treatments in patients with COVID-19 or to establish different treatment recommendations in this subgroup of patients with ischemic stroke. Our findings can be taken into consideration for treatment decisions, patient monitoring, and establishing prognosis.The study was registered under ClinicalTrials.gov identifier NCT04895462.
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