110 research outputs found

    Radical mediated heterocycle functionalization: methodology development and natural product synthesis

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    Substituted heterocycles are common building-blocks for biologically relevant molecules and represent challenging synthetic targets. Due to limited methods available for their preparation and derivatization, direct C-H functionalization protocols offer considerable advantages. Radical chemistry has shown great potential in this regard; however traditional approaches are unattractive due to poor selectivity and harsh reaction conditions. Visible light photoredox catalysis, on the other hand, is a mild alternative for alkyl radical generation and has proven its utility in organic synthesis. The work encompassed in this thesis details the efforts towards the development of practical photoredox-based functionalizations of heterocycles. Specific focus is placed upon overcoming obstacles pertaining to H-atom abstraction, back electron transfer, and redox strength of photocatalysts to achieve efficient C-Br bond reductions, amine oxidations, and C-C bond formations. In pursuit of these objectives, a C2-selective malonation of indoles and other electron-rich heteroarenes was accomplished in high yields using photocatalyst Ru(bpy)3Cl2, p-CH3OC6H4NPh, and blue LEDs as the light source. Use of a triarylamine over a trialkylamine suppressed H-atom abstraction and promoted C-C bond formation. Subsequent exploitation of the reductive quenching cycle of Ru(bpy)3Cl2 and use of Cl3CBr as an alternative oxidant led to an oxidative nucleophilic trapping of tetrahydroisoquinolines to provide a diverse set of analogues. Finally, photoredox catalysis was utilized for the creation of C-C bonds in the context of complex molecule synthesis. A variety of bromopyrroloindolines and indoles were coupled to furnish C3-C3' and C3-C2' bisindole alkaloids, which was successfully applied to the total synthesis of gliocladin C and related analogues. Moreover, fine-tuning of the redox cycle with photocatalyst Ir(ppy)2(dtbbpy)PF6 and LiB(cat)2 as the reductive quencher enabled the coupling less-reactive substrates and suppression of back electron transfer

    A expansão da União Européia e suas consequências no mercado de trabalho do Reino Unido

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    Com a expansão da União Européia em 2004, entram na comunidade o grupo de países chamado de A-8 (República Tcheca, Estônia, Letônia, Hungria, Lituânia, Polônia, Eslováquia e Eslovênia). Com a entrada desses países, aonde a situação econômica é relativamente pior as dos países que já eram membros, o fluxo migratório dentro a da União Européia aumenta consideravelmente, tendo como um dos principais destinos o Reino Unido. Tendo em vista este cenário, este estudo procura entender quais os principais impactos que esta expansão da União Européia e consequentemente o aumento na quantidade de imigrantes provenientes destes novos Estados-membros pode ter gerado no mercado de trabalho inglês

    Post-fire resprout in an endangered and narrow endemic shrub from rupestrian grasslands, Serra do Cipó, southeastern Brazil

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    Embora existam evidências de que a vegetação dos campos rupestres seja resiliente à passagem do fogo, são incipientes as investigações sobre os efeitos da crescente frequência de incêndios de origem antrópica em plantas raras e endêmicas desse ecossistema. Neste estudo, monitoramos o rebrotamento pós-fogo da espécie Coccoloba cereifera Schwacke (Polygonaceae), um arbusto ameaçado e endêmico dos campos rupestres do sudeste do Brasil. Cinco meses após o incêndio, rebrotaram 100% dos indivíduos monitorados. Entretanto, um ano após o incêndio, as plantas queimadas ainda apresentaram comprimento da rameta 24% inferior e número de folhas 53,5% inferior em relação ao porte das plantas não queimadas. As plantas queimadas apresentaram taxa de crescimento relativo em número de folhas muito superior e investimento reprodutivo muito inferior em comparação com as plantas não queimadas. Embora a espécie estudada demonstre alta capacidade de rebrotamento pós-fogo, o padrão de crescimento vegetativo e investimento reprodutivo apresentado pelas plantas rebrotadas indica que a crescente frequência de incêndios antrópicos represente uma séria ameaça para C. cereifera.Palavras-chave: Cadeia do Espinhaço, conservação, Coccoloba cereifera, crescimento de plantas, fenologia reprodutiva.Although there is evidence that the vegetation from rupestrian grasslands is resilient to fire, investigations about the effects of increasing frequency of anthropogenic fires in the rare and endemic plants from this ecosystem are still incipient. In this study, we monitored the post-fire resprouting of the endemic and endangered shrub species Coccoloba cereifera Schwacke (Polygonaceae) from rupestrian grasslands, southeastern Brazil. Five months after the fire 100% of the monitored individuals resprouted. However, one year after the fire, the burned plants had the ramet length 24% lower and number of leaves 53.5% smaller in relation to unburned plants. Burned plants showed a much higher relative growth rate in number of leaves and much lower reproductive investment compared to unburned plants. Although the studied species showed a high ability to resprout after fire, the pattern of vegetative growth and reproductive investment showed by the burned plants suggested that the increasing frequency of anthropogenic fires represents a serious threat to C. cereifera.Keywords: Coccoloba cereifera, conservation, Espinhaço Range, plant growth, reproductive phenology

    Peripheral Blood Stem Cells versus Bone Marrow for T Cell-Replete Haploidentical Transplantation with Post-Transplant Cyclophosphamide in Hodgkin Lymphoma.

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    Abstract Haploidentical stem cell transplantation (haplo-SCT) with post-transplant cyclophosphamide (PT-Cy) represents a potential curative strategy for patients with Hodgkin lymphoma (HL) when a matched related or unrelated donor is not available. The role of graft source, either bone marrow (BM) or peripheral blood stem cells (PBSCs), in this setting has not been fully elucidated. We performed a retrospective study on 91 patients with HL to compare the outcome after BM (n = 53) or PBSC (n = 38) transplant. Eighty-nine patients engrafted with no difference between BM and PBSCs in terms of median time for neutrophil (20 versus 20 days, P = .405) and platelet (26 versus 26.5 days, P = .994) engraftment. With a median follow-up of 40.2 months, 100-day cumulative incidences of grades II to IV acute graft-versus host disease (GVHD) and grades II to IV acute GVHD were 24% and 4%, respectively. Graft source was not associated with a different risk of acute GVHD both by univariate and multivariate analyses. Consistently, 1-year cumulative incidence of chronic GVHD was 7% with no differences between the 2 graft types (P = .761). Two-year rates of overall survival (OS), progression-free survival (PFS), nonrelapse mortality, and GVHD/relapse-free survival (GRFS) were 67%, 58%, 20%, and 52%, respectively. By univariate analysis, pretransplant disease status was the main variable affecting all outcomes. By multivariate analysis, PBSCs resulted in a protective factor for OS (hazard ratio [HR], .29; P = .006), PFS (HR, .38; P = .001), and GRFS (HR, .44; P = .020). The other independent variables affecting the final outcome were pretransplant disease status and hematopoietic cell transplant–specific comorbidity index. In conclusion, when planning a haplo-SCT with PT-Cy for patients with poor-risk HL, graft type is an important variable to take into account when selecting the best available donor

    Immunochip analysis identifies multiple susceptibility loci for systemic sclerosis

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    In this study, 1,833 systemic sclerosis (SSc) cases and 3,466 controls were genotyped with the Immunochip array. Classical alleles, amino acid residues, and SNPs across the human leukocyte antigen (HLA) region were imputed and tested. These analyses resulted in a model composed of six polymorphic amino acid positions and seven SNPs that explained the observed significant associations in the region. In addition, a replication step comprising 4,017 SSc cases and 5,935 controls was carried out for several selected non-HLA variants, reaching a total of 5,850 cases and 9,401 controls of European ancestry. Following this strategy, we identified and validated three SSc risk loci, including DNASE1L3 at 3p14, the SCHIP1-IL12A locus at 3q25, and ATG5 at 6q21, as well as a suggested association of the TREH-DDX6 locus at 11q23. The associations of several previously reported SSc risk loci were validated and further refined, and the observed peak of association in PXK was related to DNASE1L3. Our study has increased the number of known genetic associations with SSc, provided further insight into the pleiotropic effects of shared autoimmune risk factors, and highlighted the power of dense mapping for detecting previously overlooked susceptibility loci

    Payers' views of the changes arising through the possible adoption of adaptive pathways

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    Payers are a major stakeholder in any considerations and initiatives concerning adaptive licensing of new medicinal products, also referred to as Medicines Adaptive Pathways to patients (MAPPs). Firstly, the scope and necessity of MAPPs need further scrutiny, especially with regard to the definition of unmet need. Conditional approval pathways already exist for new medicines for seriously debilitating or life-threatening diseases and only a limited number of new medicines are innovative. Secondly, MAPPs will result in new medicines on the market with limited evidence about their effectiveness and safety. Additional data are to be collected after approval. Consequently, adaptive pathways may increase the risk of exposing patients to ineffective or unsafe medicines. We have already seen medicines approved conventionally that subsequently proved ineffective or unsafe amongst a wider, more co-morbid population as well as medicines that could have been considered for approval under MAPPs but subsequently proved ineffective or unsafe in Phase III trials and were never licensed. Thirdly, MAPPs also put high demands on payers. Routine collection of patient level data is difficult with high transaction costs. It is not clear who will fund these. Other challenges for payers include shifts in the risk governance framework, implications for evaluation and HTA, increased complexity of setting prices, difficulty with ensuring equity in the allocation of resources, definition of responsibility and liability and implementation of stratified use. Exit strategies also need to be agreed in advance, including price reductions, rebates, or reimbursement withdrawals when price premiums are not justified. These issues and concerns will be discussed in detail including potential ways forward

    Efficacy and Safety of Lenabasum, a Cannabinoid Type 2 Receptor Agonist, in a Phase 3 Randomized Trial in Diffuse Cutaneous Systemic Sclerosis

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    INTRODUCTION: Efficacy and safety of lenabasum, a cannabinoid type 2-receptor agonist, was tested in a Phase 3 study in patients with diffuse cutaneous systemic sclerosis (dcSSc). METHODS: A multi-national double-blind study was conducted in 365 dcSSc patients who were randomized and dosed 1:1:1 with lenabasum 20 mg, lenabasum 5 mg, or placebo, each twice daily and added to background treatments including immunosuppressive therapies (IST). RESULTS: The primary endpoint, ACR Combined Response Index in dcSSc (ACR-CRISS) score at Week 52, lenabasum 20 mg BID versus placebo, was not met, with ACR-CRISS scores of 0.888 versus 0.887, P = 0.4972, mixed models repeated measures (MMRM). Change in modified Rodnan Skin Score (mRSS) at Week 52 was -6.7 versus -8.1 points for lenabasum 20 mg BID versus placebo, P = 0.1183, MMRM. Pre-specified analyses showed higher ACR-CRISS scores, greater improvement in mRSS, and less decline in forced vital capacity in subjects on background mycophenolate and those receiving IST for ≤ 1 year duration. No deaths or excess in serious or severe adverse events related to lenabasum were observed. CONCLUSIONS: A benefit of lenabasum in dcSSc was not demonstrated. The majority of patients were treated with background IST, and treatment with MMF in particular was associated with better outcomes. This supports the use of IST in the treatment of dcSSc, and highlights the challenge of demonstrating a treatment effect when investigational treatment is added to standard of care IST. These findings have relevance to trial design in SSc, as well as clinical care

    Tetrahymena Metallothioneins Fall into Two Discrete Subfamilies

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    BACKGROUND: Metallothioneins are ubiquitous small, cysteine-rich, multifunctional proteins which can bind heavy metals. METHODOLOGY/PRINCIPAL FINDINGS: We report the results of phylogenetic and gene expression analyses that include two new Tetrahymena thermophila metallothionein genes (MTT3 and MTT5). Sequence alignments of all known Tetrahymena metallothioneins have allowed us to rationalize the structure of these proteins. We now formally subdivide the known metallothioneins from the ciliate genus Tetrahymena into two well defined subfamilies, 7a and 7b, based on phylogenetic analysis, on the pattern of clustering of Cys residues, and on the pattern of inducibility by the heavy metals Cd and Cu. Sequence alignment also reveals a remarkably regular, conserved and hierarchical modular structure of all five subfamily 7a MTs, which include MTT3 and MTT5. The former has three modules, while the latter has only two. Induction levels of the three T. thermophila genes were determined using quantitative real time RT-PCR. Various stressors (including heavy metals) brought about dramatically different fold-inductions for each gene; MTT5 showed the highest fold-induction. Conserved DNA motifs with potential regulatory significance were identified, in an unbiased way, upstream of the start codons of subfamily 7a MTs. EST evidence for alternative splicing in the 3′ UTR of the MTT5 mRNA with potential regulatory activity is reported. CONCLUSION/SIGNIFICANCE: The small number and remarkably regular structure of Tetrahymena MTs, coupled with the experimental tractability of this model organism for studies of in vivo function, make it an attractive system for the experimental dissection of the roles, structure/function relationships, regulation of gene expression, and adaptive evolution of these proteins, as well as for the development of biotechnological applications for the environmental monitoring of toxic substances

    Rheumatoid arthritis - treatment: 180. Utility of Body Weight Classified Low-Dose Leflunomide in Japanese Rheumatoid Arthritis

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    Background: In Japan, more than 20 rheumatoid arthritis (RA) patients died of interstitial pneumonia (IP) caused by leflunomide (LEF) were reported, but many of them were considered as the victims of opportunistic infection currently. In this paper, efficacy and safety of low-dose LEF classified by body weight (BW) were studied. Methods: Fifty-nine RA patients were started to administrate LEF from July 2007 to July 2009. Among them, 25 patients were excluded because of the combination with tacrolimus, and medication modification within 3 months before LEF. Remaining 34 RA patients administered 20 to 50 mg/week of LEF were followed up for 1 year and enrolled in this study. Dose of LEF was classified by BW (50 mg/week for over 50 kg, 40 mg/week for 40 to 50 kg and 20 to 30 mg/week for under 40 kg). The average age and RA duration of enrolled patients were 55.5 years old and 10.2 years. Prednisolone (PSL), methotrexate (MTX) and etanercept were used in 23, 28 and 2 patients, respectively. In case of insufficient response or adverse effect, dosage change or discontinuance of LEF were considered. Failure was defined as dosages up of PSL and MTX, or dosages down or discontinuance of LEF. Last observation carried forward method was used for the evaluation of failed patients at 1 year. Results: At 1 year after LEF start, good/ moderate/ no response assessed by the European League Against Rheumatism (EULAR) response criteria using Disease Activity Score, including a 28-joint count (DAS28)-C reactive protein (CRP) were showed in 14/ 10/ 10 patients, respectively. The dosage changes of LEF at 1 year were dosage up: 10, same dosage: 5, dosage down: 8 and discontinuance: 11 patients. The survival rate of patients in this study was 23.5% (24 patients failed) but actual LEF continuous rate was 67.6% (11 patients discontinued) at 1 year. The major reason of failure was liver dysfunction, and pneumocystis pneumonia was occurred in 1 patient resulted in full recovery. One patient died of sepsis caused by decubitus ulcer infection. DAS28-CRP score was decreased from 3.9 to 2.7 significantly. Although CRP was decreased from 1.50 to 0.93 mg/dl, it wasn't significant. Matrix metalloproteinase (MMP)-3 was decreased from 220.0 to 174.2 ng/ml significantly. Glutamate pyruvate transaminase (GPT) was increased from 19 to 35 U/l and number of leukocyte was decreased from 7832 to 6271 significantly. DAS28-CRP, CRP, and MMP-3 were improved significantly with MTX, although they weren't without MTX. Increase of GPT and leukopenia were seen significantly with MTX, although they weren't without MTX. Conclusions: It was reported that the risks of IP caused by LEF in Japanese RA patients were past IP history, loading dose administration and low BW. Addition of low-dose LEF is a potent safe alternative for the patients showing unsatisfactory response to current medicines, but need to pay attention for liver function and infection caused by leukopenia, especially with MTX. Disclosure statement: The authors have declared no conflicts of interes
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