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[Continuous Glucose Monitoring. Which is the evidence in Children?]. ANDES PEDIATRICA : REVISTA CHILENA DE PEDIATRIA 2021; 92:617-625. [PMID: 34652382 DOI: 10.32641/andespediatr.v92i4.2973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 03/22/2021] [Indexed: 06/13/2023]
Abstract
Diabetes Technology refers to the software or hardware that is designed to facilitate and improve the quality of life of the patient with diabetes Mellitus. A non-systematic literature search was carried out which included articles in English and Spanish about the use of continuous glucose monitoring (CGM) in pediatric patients with Type 1 diabetes Mellitus. This review summarizes the performance of the CGM, its accuracy, and classification. A chronological synthesis of the general evidence up to June 2020 was done including both adult and pediatric studies. Aspects of metabolic control were specified on the use of real-time and intermittent / flash CGM, such as reduction of HbA1c levels, reduction in frequency and severity of hypoglycemia, decrease in episodes of ketoacidosis and well being, and variables such as the Frequency of CGM use, which have been related to the improvement of the objectives of diabetes control. This review presents a chronological summary of the evidence for flash glucose monitoring in studies where only pediatric population is included and provides an account of diabetes technology recommendations that apply to pediatric population from the Ame rican Diabetes Association 2020 guideline, the International Society for Pediatric and Adolescent Diabetes 2018 recommendations.
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Transitioning a cardiovascular health and rehabilitation programme to a virtual platform during covid 19. Eur J Cardiovasc Nurs 2021. [DOI: 10.1093/eurjcn/zvab060.073] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract
Funding Acknowledgements
Type of funding sources: None.
OnBehalf
Our Hearts Our Minds
Purpose
Can a virtual cardiovascular prevention and rehabilitation programme be as effective as face-to-face programme.
Background
The Our Hearts Our Minds (OHOM) prevention and rehabilitation programme rapidly transitioned to a virtual platform in the covid era. Here we compare if a virtual programme potentially could offer the same standard of the nursing intervention (education, smoking cessation, medical risk factor management and psychosocial health) as the previous face to face programme
Methods
Both the initial assessment (IA) and end of programme (EOP) assessments were conducted via telephone/video as per patient preference. The following measures were recorded at both time points (home blood pressure (BP) monitors were provided)
Smoking (self report) BP/Heart rate, Lipids/HbA1c (facilitated by phlebotomy hub), cardio protective drugs (doses, adherence), Hospital Anxiety and Depression score, EuroQoL
Nursing Intervention Smoking cessation counselling and pharmacotherapy where appropriate
Weekly meeting with cardiologist to optimise BP and lipid management and up titration cardio protective drugs
Bimonthly virtual coaching consultation for monitoring/goal resetting
Bimonthly group video education sessions
Results
From April to November 2020, of the 432 referrals received 400 were eligible with 377 accepting the offer of an IA (94% response rate). 262 have had an IA with the remaining 115 awaiting an assessment date. Of the completed IA’s 257 were willing to attend the programme (98% uptake). 120 had been offered an end of programme assessment with 114 attending (96% of those offered). The results for the virtual programme were then compared to the same period one year previously when the programme was fully face to face and are outlined in the table below.
The comparison of results delivered via remote delivery are remarkably similar to those achieved in the previous year delivered via face to face.
Conclusion
Initial data has shown that virtual delivery of the nursing component of the OHOM prevention/rehabilitation programme was highly acceptable to patients and was as effective as that of the traditional face to face service.
Table 1 below exhibits the clinical and patient-reported outcomes.
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Ecological and economic effects of COVID-19 in marine fisheries from the Northwestern Mediterranean Sea. BIOLOGICAL CONSERVATION 2021; 255:108997. [PMID: 33558776 PMCID: PMC7859691 DOI: 10.1016/j.biocon.2021.108997] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 01/04/2021] [Accepted: 01/16/2021] [Indexed: 05/19/2023]
Abstract
The SARS-CoV-2 coronavirus pandemic starting at the end of 2019 impacted many human activities. We analysed the abrupt reduction in fishing pressure of the mixed small-scale and industrial fisheries in the Catalan Sea, Spanish Mediterranean, and resulting ecological and economic impacts during the first half of 2020. We used detailed fisheries data on fishing effort, landings, revenues, landings per unit of effort (LPUE) and revenues per unit of effort from January to June 2020, and complemented it with the outcomes of a marine ecosystem model. We analysed data from 2017 to 2019 and compared these to 2020 to characterise changes in the fishing activity from before (January-February) to during (March-May) the lockdown. Fishing effort during the lockdown dropped by 34%, landings were down by 49% and revenues declined by 39% in comparison with the same period in 2017-2019. LPUEs did not show significant changes during the lockdown, with the exception of shrimp species, especially the deep-water rose shrimp, which significantly increased in LPUE during March-May. These increases may reflect positive effects of reduced fishing on fast-growing species. Positive effects mostly disappeared in June 2020 with the relaxation of the lockdown. In agreement, the ecological simulations projected slight short-term increases of biomass for fast-growing, small-sized organisms during 2020, which quickly vanished when fishing resumed, and which had no detectable ecosystem effects. Three additional alternative ecological simulations illustrated that to substantially recover commercial species and ensure ecosystem sustainability in the study area, a sustained and notable reduction of fishing activity would be needed.
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Lamotrigine induced Brugada-pattern in a patient with genetic epilepsy associated with a novel variant in SCN9A. Gene 2020; 754:144847. [PMID: 32531456 DOI: 10.1016/j.gene.2020.144847] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/22/2020] [Accepted: 06/02/2020] [Indexed: 01/28/2023]
Abstract
BACKGROUND A 30-year-old man presented with intellectual disability associated with epilepsy. The epilepsy was initially treated with sodium valproate and since he was 28 years-old with lamotrigine. With the addition of lamotrigine, a pattern of Brugada syndrome appeared on the electrocardiogram. The family history was positive for epilepsy from the motheŕs side, who had never been treated with lamotrigine. OBJECTIVE Determine the genetic cause of the intellectual disability, epilepsy and Brugada syndrome of the patient and try to establish a possible correlation between the genetic background and the Brugada syndrome pattern under lamotrigine treatment. METHODS A standard karyotype, array comparative genomic hybridization and two different NGS panels have done to the index case to identify the genetic causes of the intellectual disability, epilepsy and Brugada syndrome pattern. RESULTS Genetic analyses in the family identified a de novo duplication of 1.3 Mb in 8p21.3 as well as two novel heterozygous rare variants in SCN9A and AKAP9 genes, both inherited from the mother. CONCLUSION We hypothesize that in this family the SCN9A variant was responsible for the epileptic syndrome. In addition, given that SCN9A is lightly expressed in the heart tissue, we postulate that this SCN9A variant, alone or in combination with AKAP9 variant, might be responsible for the Brugada pattern when challenged by lamotrigine.
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Predicting marine species distributions: Complementarity of food-web and Bayesian hierarchical modelling approaches. Ecol Modell 2019. [DOI: 10.1016/j.ecolmodel.2019.05.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Rare earths separation from fluorescent lamp wastes using ionic liquids as extractant agents. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 82:241-248. [PMID: 30509586 DOI: 10.1016/j.wasman.2018.10.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 10/19/2018] [Accepted: 10/19/2018] [Indexed: 06/09/2023]
Abstract
Processing of end-of-life products has become essential in the rare earth elements (REEs) recovery field because the demand for these metals has increased over the last years due to their intensive use in advanced technologies. Fluorescent lamp wastes are considered one of the most interesting end-of-life products for investigation due to their high REEs content, mainly yttrium and europium. As a result, red phosphors (Y2O3:Eu3+ - YOX) have been chosen for evaluating their REEs' recovery potential. The REEs from a YOX reach liquor, coming from a soft leaching process have been precipitated adding oxalic acid and calcined to get the REEs in oxide form. Cyanex 572, D2EHPA and the ionic liquids, Primene 81R·Cyanex 572 IL and Primene 81R·D2EHPA IL, have been chosen to investigate the efficiency of REEs separation in chloride media. Yttrium, europium and cerium have been individually recovered by a four stages cross-flow solvent extraction process using the Primene 81R·D2EHPA IL and the Primene 81R·Cyanex 572 IL as extractants. Ce(III), Eu(III) and Y(III) have been obtained at high purities ≥ 99.9%. 4 mol/L HCl has been used to recover the yttrium and the europium from the organic phases.
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Future scenarios of marine resources and ecosystem conditions in the Eastern Mediterranean under the impacts of fishing, alien species and sea warming. Sci Rep 2018; 8:14284. [PMID: 30250047 PMCID: PMC6155163 DOI: 10.1038/s41598-018-32666-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 09/07/2018] [Indexed: 11/17/2022] Open
Abstract
Using a temporal-dynamic calibrated Ecosim food web model, we assess the effects of future changes on marine resources and ecosystem conditions of the Israeli Mediterranean continental shelf. This region has been intensely invaded by Indo-Pacific species. The region is exposed to extreme environmental conditions, is subjected to high rates of climate change and has experienced intense fishing pressure. We test the impacts of a new set of fishing regulations currently being implemented, a continued increase in sea temperatures following IPCC projections, and a continued increase in alien species biomass. We first investigate the impacts of the stressors separately, and then we combine them to evaluate their cumulative effects. Our results show overall potential future benefits of fishing effort reductions, and detrimental impacts of increasing sea temperature and increasing biomass of alien species. Cumulative scenarios suggest that the beneficial effects of fisheries reduction may be dampened by the impact of increasing sea temperature and alien species when acting together. These results illustrate the importance of including stressors other than fisheries, such as climate change and biological invasions, in an ecosystem-based management approach. These results support the need for reducing local and regional stressors, such as fishing and biological invasions, in order to promote resilience to sea warming.
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Neodymium recovery from NdFeB magnet wastes using Primene 81R·Cyanex 572 IL by solvent extraction. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 222:359-367. [PMID: 29870964 DOI: 10.1016/j.jenvman.2018.05.054] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/25/2018] [Accepted: 05/16/2018] [Indexed: 06/08/2023]
Abstract
The necessity of Rare Earth Elements (REEs) recycling is crucial to minimizing their supply risk and provide an alternative to greener technologies. Hence, the REEs recovery from NdFeB magnet wastes using cationic extractants by solvent extraction technique has been investigated in this research. Due to the difficulty in maintaining the aqueous pH in the industrial counter-current devices when extractants like Cyanex 272 or Cyanex 572 are used, the Primene 81R·Cyanex 572 ionic liquid has been synthesised to overcome this. 99.99% Nd(III) recovery with a purity of 99.7% from an aqueous mixture of Nd/Tb/Dy in chloride medium, the three representative REEs present in the NdFeB magnets wastes, has been achieved after two stages counter-current extraction process using 0.30 M of Primene 81R·Cyanex 572 ionic liquid (1:4 A:O ratio) diluted in Solvesso 100, without any aqueous pH conditioning.
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P6266Homozygous familial hypercholesterolemia: A study of 36 cases with phenotype of homozygous familiar hypercholesterolemia in Colombia. Eur Heart J 2018. [DOI: 10.1093/eurheartj/ehy566.p6266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Photo-identification as a tool to study small-spotted catshark Scyliorhinus canicula. JOURNAL OF FISH BIOLOGY 2018; 92:1657-1662. [PMID: 29624692 DOI: 10.1111/jfb.13609] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 02/26/2018] [Indexed: 06/08/2023]
Abstract
Photo-identification (photo-ID) was tested as a means to identify individual small-spotted catsharks Scyliorhinus canicula. The spotting pattern of the caudal region of S. canicula was used for the tests and revealed that photo-ID is an efficient method to identify individuals. Photo-ID is logistically simple, making it a potential alternative to traditional tagging to provide information on the distribution patterns and population dynamics of S. canicula and related species.
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11
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P1694Natural and undetermined sudden death: value of post-mortem genetic investigation. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx502.p1694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Untangling surface oxygen exchange effects in YBa 2Cu 3O 6+x thin films by electrical conductivity relaxation. Phys Chem Chem Phys 2017; 19:14129-14140. [PMID: 28524207 DOI: 10.1039/c7cp01855j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The kinetics of oxygen incorporation (in-diffusion process) and excorporation (out-diffusion process), in YBa2Cu3O6+x (YBCO) epitaxial thin films prepared using the chemical solution deposition (CSD) methodology by the trifluoroacetate route, was investigated by electrical conductivity relaxation measurements. We show that the oxygenation kinetics of YBCO films is limited by the surface exchange process of oxygen molecules prior to bulk diffusion into the films. The analysis of the temperature and oxygen partial pressure influence on the oxygenation kinetics has drawn a consistent picture of the oxygen surface exchange process enabling us to define the most likely rate determining step. We have also established a strategy to accelerate the oxygenation kinetics at low temperatures based on the catalytic influence of Ag coatings thus allowing us to decrease the oxygenation temperature in the YBCO thin films.
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Modelling marine ecosystems using the Ecopath with Ecosim food web approach: New insights to address complex dynamics after 30 years of developments. Ecol Modell 2016. [DOI: 10.1016/j.ecolmodel.2016.04.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Neutrophil gelatinase-associated lipocalin is a biomarker of acute-on-chronic liver failure and prognosis in cirrhosis. J Hepatol 2016; 65:57-65. [PMID: 26988732 DOI: 10.1016/j.jhep.2016.03.002] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 03/03/2016] [Accepted: 03/06/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND & AIMS Acute-on-chronic liver failure (ACLF) is a syndrome that occurs in cirrhosis characterized by organ failure(s) and high mortality rate. There are no biomarkers of ACLF. The LCN2 gene and its product, neutrophil gelatinase-associated lipocalin (NGAL), are upregulated in experimental models of liver injury and cultured hepatocytes as a result of injury by toxins or proinflammatory cytokines, particularly Interleukin-6. The aim of this study was to investigate whether NGAL could be a biomarker of ACLF and whether LCN2 gene may be upregulated in the liver in ACLF. METHODS We analyzed urine and plasma NGAL levels in 716 patients hospitalized for complications of cirrhosis, 148 with ACLF. LCN2 expression was assessed in liver biopsies from 29 additional patients with decompensated cirrhosis with and without ACLF. RESULTS Urine NGAL was markedly increased in ACLF vs. no ACLF patients (108(35-400) vs. 29(12-73)μg/g creatinine; p<0.001) and was an independent predictive factor of ACLF; the independent association persisted after adjustment for kidney function or exclusion of variables present in ACLF definition. Urine NGAL was also an independent predictive factor of 28day transplant-free mortality together with MELD score and leukocyte count (AUROC 0.88(0.83-0.92)). Urine NGAL improved significantly the accuracy of MELD in predicting prognosis. The LCN2 gene was markedly upregulated in the liver of patients with ACLF. Gene expression correlated directly with serum bilirubin and INR (r=0.79; p<0.001 and r=0.67; p<0.001), MELD (r=0.68; p<0.001) and Interleukin-6 (r=0.65; p<0.001). CONCLUSIONS NGAL is a biomarker of ACLF and prognosis and correlates with liver failure and systemic inflammation. There is remarkable overexpression of LCN2 gene in the liver in ACLF syndrome. LAY SUMMARY Urine NGAL is a biomarker of acute-on-chronic liver failure (ACLF). NGAL is a protein that may be expressed in several tissues in response to injury. The protein is filtered by the kidneys due to its small size and can be measured in the urine. Ariza, Graupera and colleagues found in a series of 716 patients with cirrhosis that urine NGAL was markedly increased in patients with ACLF and correlated with prognosis. Moreover, gene coding NGAL was markedly overexpressed in the liver tissue in ACLF.
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Predicting the Burden of Knee Arthroplasty Revision Over A 20-Year Horizon. VALUE IN HEALTH : THE JOURNAL OF THE INTERNATIONAL SOCIETY FOR PHARMACOECONOMICS AND OUTCOMES RESEARCH 2014; 17:A388-A389. [PMID: 27200884 DOI: 10.1016/j.jval.2014.08.2660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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P335Sudden unexplained death in Catalonia: comprehensive genetic analysis in post-mortem samples. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu091.22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Abstract
Abstract
Anabasine is the major volatile product in the poison gland exudate of Messor ebeninus, acting as a defensive compound. Exudates of the poison gland also contain minor, yet unidentified, components that are possibly responsible for the alarm behavior that is also elicited by the venom.
Dufour’s gland secretion is characterized by aliphatic hydrocarbons of which 1-pentadecene predominates. Upon exposure to Dufour’s gland secretion the ants recruited to the emitting source, but did not exhibit any aggressive behavior. The possible concordant effects of both adnexal glands secretions is discussed.
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SAT0234 Valvular heart disease in antiphospholipid syndrome. Ann Rheum Dis 2013. [DOI: 10.1136/annrheumdis-2012-eular.3181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Effectiveness of an interactive virtual telerehabilitation system in patients after total knee arthoplasty: A randomized controlled trial. J Rehabil Med 2013; 45:392-6. [DOI: 10.2340/16501977-1119] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Wide variation in spatial genetic structure between natural populations of the European beech (Fagus sylvatica) and its implications for SGS comparability. Heredity (Edinb) 2012; 108:633-9. [PMID: 22354112 DOI: 10.1038/hdy.2012.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Identification and quantification of spatial genetic structure (SGS) within populations remains a central element of understanding population structure at the local scale. Understanding such structure can inform on aspects of the species' biology, such as establishment patterns and gene dispersal distance, in addition to sampling design for genetic resource management and conservation. However, recent work has identified that variation in factors such as sampling methodology, population characteristics and marker system can all lead to significant variation in SGS estimates. Consequently, the extent to which estimates of SGS can be relied on to inform on the biology of a species or differentiate between experimental treatments is open to doubt. Following on from a recent report of unusually extensive SGS when assessed using amplified fragment length polymorphisms in the tree Fagus sylvatica, we explored whether this marker system led to similarly high estimates of SGS extent in other apparently similar populations of this species. In the three populations assessed, SGS extent was even stronger than this previously reported maximum, extending up to 360 m, an increase in up to 800% in comparison with the generally accepted maximum of 30-40 m based on the literature. Within this species, wide variation in SGS estimates exists, whether quantified as SGS intensity, extent or the Sp parameter. Consequently, we argue that greater standardization should be applied in sample design and SGS estimation and highlight five steps that can be taken to maximize the comparability between SGS estimates.
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Nanoscale strain-induced pair suppression as a vortex-pinning mechanism in high-temperature superconductors. NATURE MATERIALS 2012; 11:329-336. [PMID: 22327747 DOI: 10.1038/nmat3247] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 01/11/2012] [Indexed: 05/31/2023]
Abstract
Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centres in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa(2)Cu(3)O(7) matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.
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Structural characterization of the conjugation machinery in G+ bacteria. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311087964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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23
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Structural analysis of tubulin binding cofactor complexes by electron microscopy and image processing. Acta Crystallogr A 2011. [DOI: 10.1107/s010876731109427x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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The crystal structure of TBC domain of human GapCenA. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311094487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Purification and crystallization of a protein-DNA complex. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311091288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Mathematical modeling of cadmium(II) solvent extraction from neutral and acidic chloride media using Cyanex 923 extractant as a metal carrier. JOURNAL OF HAZARDOUS MATERIALS 2010; 182:903-911. [PMID: 20673611 DOI: 10.1016/j.jhazmat.2010.07.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Revised: 05/21/2010] [Accepted: 07/01/2010] [Indexed: 05/29/2023]
Abstract
This paper describes experimental work and the mathematical modeling of solvent extraction of cadmium(II) from neutral and acidic aqueous chloride media with a Cyanex 923 extractant in Exxol D-100. Solvent extraction experiments were carried out to analyze the influence of variations in the composition of the aqueous and organic phases on the efficiency of cadmium(II) extraction. In neutral and acidic chloride conditions, the extraction of cadmium(II) by the organophosphorous extractant Cyanex 923 (L) is based on the solvation mechanism of neutral H(n)CdCl((2+n)) species and the formation of H(n)CdCl((2+n))L(q) complexes in the organic phase, where n=0, 1, 2 and q=1, 2. The mathematical model of cadmium(II) extraction was derived from the mass balances and chemical equilibria involved in the separation system. The model was computed with the Matlab software. The equilibrium parameters for metal extraction, i.e. the stability constants of the aqueous Cd-Cl complexes, the formation constants of the acidic Cd-Cl species and the metal equilibrium extraction constants, were proposed. The optimized constants were appropriate, as there was good agreement when the model was fitted to the experimental data for each of the experiments.
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Nanostructural control in solution-derived epitaxial Ce(1-x)Gd(x)O(2-y) films. NANOTECHNOLOGY 2008; 19:395601. [PMID: 21832597 DOI: 10.1088/0957-4484/19/39/395601] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A novel mechanism based on aliovalent doping, allowing fine tuning of the nanostructure and surface topography of solution-derived ceria films, is reported. While under reducing atmospheric conditions, non-doped ceria films are inherently polycrystalline due to an interstitial amorphous Ce(2)C(3) phase that inhibits grain growth, a high quality epitaxial film can be achieved simply by doping with Gd(3+) cations. Gd(3+) [Formula: see text] Ce(4+) substitutions within the lattice are accompanied by charge-compensating oxygen vacancies throughout the volume of the crystallites acting as an efficient vehicle to reduce the barrier for grain boundary motion caused by interstitial Ce(2)C(3). In this way, the original nanostructure is self-purified by pushing the amorphous Ce(2)C(3) phase towards the free surface of the film. Once a full epitaxial cube-on-cube oriented ceria film is obtained, its surface morphology is dictated by the interplay between faceting on low energy {110} and/or {111} pyramidal planes and truncation of those pyramids by (001) ones. The development of the latter requires the suppression of their polar character which is thought to be achieved by charge compensation between the dopand and oxygen along [Formula: see text] directions.
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Molecular recognition and self-organization of three-way DNA junctions and supramolecular helicates. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308096657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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DNA transfer machines. Acta Crystallogr A 2008. [DOI: 10.1107/s0108767308099212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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The VIZIER project: preparedness against pathogenic RNA viruses. Antiviral Res 2007; 78:37-46. [PMID: 18083241 PMCID: PMC7114271 DOI: 10.1016/j.antiviral.2007.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 10/15/2007] [Accepted: 10/16/2007] [Indexed: 01/07/2023]
Abstract
Life-threatening RNA viruses emerge regularly, and often in an unpredictable manner. Yet, the very few drugs available against known RNA viruses have sometimes required decades of research for development. Can we generate preparedness for outbreaks of the, as yet, unknown viruses? The VIZIER (VIral enZymes InvolvEd in Replication) (http://www.vizier-europe.org/) project has been set-up to develop the scientific foundations for countering this challenge to society. VIZIER studies the most conserved viral enzymes (that of the replication machinery, or replicases) that constitute attractive targets for drug-design. The aim of VIZIER is to determine as many replicase crystal structures as possible from a carefully selected list of viruses in order to comprehensively cover the diversity of the RNA virus universe, and generate critical knowledge that could be efficiently utilized to jump-start research on any emerging RNA virus. VIZIER is a multidisciplinary project involving (i) bioinformatics to define functional domains, (ii) viral genomics to increase the number of characterized viral genomes and prepare defined targets, (iii) proteomics to express, purify, and characterize targets, (iv) structural biology to solve their crystal structures, and (v) pre-lead discovery to propose active scaffolds of antiviral molecules.
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Cutting and moving DNA. Acta Crystallogr A 2007. [DOI: 10.1107/s0108767307099965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Application of the use of high-throughput technologies to the determination of protein structures of bacterial and viral pathogens. Corrigendum. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2006. [DOI: 10.1107/s0907444906044246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Application of the use of high-throughput technologies to the determination of protein structures of bacterial and viral pathogens. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2006; 62:1196-207. [PMID: 17001096 PMCID: PMC7161641 DOI: 10.1107/s0907444906030915] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Accepted: 08/07/2006] [Indexed: 11/11/2022]
Abstract
The Structural Proteomics In Europe (SPINE) programme is aimed at the development and implementation of high-throughput technologies for the efficient structure determination of proteins of biomedical importance, such as those of bacterial and viral pathogens linked to human health. Despite the challenging nature of some of these targets, 175 novel pathogen protein structures (approximately 220 including complexes) have been determined to date. Here the impact of several technologies on the structural determination of proteins from human pathogens is illustrated with selected examples, including the parallel expression of multiple constructs, the use of standardized refolding protocols and optimized crystallization screens.
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Tomato fruit size, maturity and alpha-tomatine content influence the performance of larvae of potato tuber moth Phthorimaea operculella (Lepidoptera: Gelechiidae). BULLETIN OF ENTOMOLOGICAL RESEARCH 2006; 96:173-8. [PMID: 16556338 DOI: 10.1079/ber2005412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Various physical and chemical properties of host plants influence insect larval performance and subsequent adult fitness. Tomato plants are relatively new hosts to the potato tuber moth, Phthorimaea operculella (Zeller), with the fruit being its preferred feeding site. However, it is unclear how the biochemical and physical properties of tomato fruits relate to potato tuber moth performance. Significant amounts of alpha-tomatine were detected in maturing green and ripening fruits of cherry (cv. Ceres) and processing (cv. Serio) types of tomatoes whereas none was detected in a fresh market variety (cv. Marglobe), at comparable stages. alpha-Tomatine is negatively and significantly correlated with development rate (head capsule size) of larvae reared in the fruits of the cherry and processing type tomatoes. Generally, survival, growth and development were significantly superior for larvae reared in the ripening fruits of the fresh market cultivar. At this stage, the fruits of this cultivar are also the largest. Based on these results it is concluded that fruit alpha-tomatine content, as well as fruit size and maturity, all affect performance of P. operculella larvae in the fruits of cultivated tomatoes.
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The Systemic Absorption of Etoposide after Intravaginal Administration in Patients with Cervical Intraepithelial Lesions Associated with Human Papillomavirus Infection. Pharm Res 2006; 23:378-83. [PMID: 16388409 DOI: 10.1007/s11095-005-9142-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE The purpose of this study was to determine the systemic absorption and the release of etoposide in cervical tissue administered via a vaginal ovule to women diagnosed with cervical intraepithelial lesions associated with human papillomavirus (HPV). METHODS Fifteen women with low- and high-grade intraepithelial neoplasia confirmed by colposcopic test received a 50-mg intravaginal etoposide dose three times a week for 3 weeks. At the end of the study period, paralleled with the last ovule administered, blood samples were collected over a period of 24 h, and in situ cervical samples were obtained at 3 and 10 h after drug administration. Etoposide concentrations were determined in plasma and in in situ cervical samples using the high-performance liquid chromatography method with electrochemical detection. RESULTS Pharmacokinetic analyses of plasma data indicated low or lack of systemic exposure of etoposide after the vaginal administration. Nevertheless, high concentrations of etoposide were found in all in situ cervical samples, indicating that etoposide could be released from its pharmaceutical formulation. CONCLUSIONS The results of the study suggest that the etoposide administered as intravaginal ovule is safe and tolerable and apparently could be a suitable option in patients with cervical intraepithelial neoplasia. Clinical results and the true impact on HPV infection and evolution of dysplasia need to be confirmed.
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Unveiling the DNA strand transfer-mechanism of relaxase TrwC. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305090628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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X-ray crystallographic studies of two transthyretin variants: further insights into amyloidogenesis. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2005; 61:333-9. [PMID: 15735344 DOI: 10.1107/s0907444904034316] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Accepted: 12/23/2004] [Indexed: 11/10/2022]
Abstract
Transthyretin (TTR) is a homotetrameric plasma protein that, as a result of a set of not yet fully characterized conformational changes, forms fibrillar aggregates that are the major protein component of amyloid deposits. More than 80 mutations associated with TTR amyloid deposition have been described in the literature. X-ray crystallography was used to elucidate the three-dimensional structure of two important TTR variants: TTR Y78F, an amyloidogenic protein, and TTR R104H, which is associated with a protective effect over the amyloidogenic V30M mutation. The structures of those two TTR variants have been determined in space group P2(1)2(1)2 to 1.55 and 1.60 angstroms resolution, respectively, using molecular-replacement techniques. Detailed analysis of the protein model for TTR Y78F indicates a destabilization of the contacts between the alpha-helix and AB loop and the body of the molecule, intimately related to the amyloidogenic nature; contrastingly, in the TTR R104H variant new contacts involving the N-terminal region and His104 are clearly antagonists of amyloid formation.
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Medical speciality and pattern of medicines prescription. Eur J Clin Pharmacol 2004; 60:725-30. [PMID: 15502994 DOI: 10.1007/s00228-004-0802-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 06/18/2004] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To describe the prescribing patterns and their quality in relation to the prescriber's medical specialty in a defined population. METHODS The study was done on a random sample of all primary care medical prescriptions made through the social security system during 1 year in Andorra, a small European country. Number and type of prescribed medicines, prescribers' medical speciality and patients' age and gender were recorded. Medical specialties considered were General Practice, Paediatrics, Cardiology, Pneumology, Gynaecology, Ophthalmology and Other. A set of various quality indicators [World Health Organisation (WHO)/International Network for Rational Use of Drugs (INRUD) indicators and others] was used. RESULTS The number of medicines prescribed per encounter varied depending on the prescriber's medical specialty and patient's age. Cardiologists and pneumologists tended to prescribe more medicines than other medical specialties. Patients older than 65 years received more prescriptions than younger adults, mostly at the expense of cardiovascular drugs. The contribution of the various groups and subgroups of medicines and the scores of various prescribing indicators showed wide variability across the medical specialties. CONCLUSION Prescribing patterns and indicators of prescription quality show wide variability depending on the prescriber's medical specialty. This has important implications for priority setting in information, continuous education and research.
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Abstract
Type IV secretion systems (T4SSs) are bacterial multiprotein organelles specialised in the transfer of (nucleo)protein complexes across cell membranes. They are essential for conjugation, bacterial-induced tumour formation in plant cells, as observed in Agrobacterium, toxin secretion, like in Bordetella and Helicobacter, cell-to-cell translocation of virulence factors, and intracellular activity of mammalian pathogens like Legionella. By enabling conjugative DNA delivery, these systems contribute to the spread of antibiotic resistance genes among bacteria. These translocons are made up by 10-15 proteins that are analogous to Vir proteins of Agrobacterium and traverse both membranes and the periplasmic space in between in Gram-negative bacteria. Their secretion substrates range from single-stranded DNA/protein complexes to multicomponent toxins and they are assisted by integral inner-membrane coupling factors, the multimeric type-IV coupling proteins (T4CPs), to connect the macromolecular complexes to be transferred with the secretory conduit. To do so, these T4CPs may be required to localise close to the secretion machinery within the donor cell. The T4CP structural prototype is the hexameric protein TrwB of Escherichia coli conjugative plasmid R388, closely related to Agrobacterium VirD4 protein. It is responsible for coupling the relaxosome with the DNA transport apparatus during cell mating. T4CP family members are related to SpoIIIE/FtsK proteins, essential for DNA pumping during sporulation and cell division. These features suggest possible mechanisms for conjugal T4CP function: as a simple coupler between two molecular machines, as a rotating device to pump DNA through the type-IV transport pore, or as a DNA injector, whereby its central channel would function as part of the transport pore.
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[Therapy options for Prinzmetal angina induced ventricular vulnerability]. ZEITSCHRIFT FUR KARDIOLOGIE 2003; 92:332-8. [PMID: 12707793 DOI: 10.1007/s00392-003-0916-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report about a 46 year old male, who survived sudden cardiac death caused by recurrent ventricular tachycardia as the clinical manifestation of a vasospastic right coronary artery. After implantation of an implantable cardioverter defibrillator, the patient did not respond to conservative treatment despite of different drug therapies. Therefore, the vasospastic right coronary artery was treated by a percutaneous transluminal coronary angioplasty and stenting, which could not reduce the occurrence of further tachycardias. Finally, the patient underwent an operative myocardial revascularization combined with sympathectomy. During the whole follow-up of six months no new episodes of ventricular tachyarrhythmias have occurred.
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Crystallization and preliminary X-ray analysis of the antimalarial and cytotoxic alkaloid cryptolepine complexed with the DNA fragment d(CCTAGG)2. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2002; 58:312-3. [PMID: 11807260 DOI: 10.1107/s0907444901018960] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2001] [Accepted: 11/07/2001] [Indexed: 11/10/2022]
Abstract
Crystals of the indoloquinoline alkaloid cryptolepine complexed with the DNA fragment d(CCTAGG)(2) have been grown by the hanging-drop technique at 293 K using ammonium sulfate as the precipitating agent. Over a period of three weeks, yellow tapering bullet-shaped crystals grew to maximum dimensions of 0.2 x 0.1 x 0.1 mm. The crystals belong to space group P6(4), with unit-cell parameters a = b = 29.960, c = 39.64 A, alpha = beta = 90, gamma = 120 degrees, and diffract to 1.4 A.
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Crystallization and preliminary X-ray analysis of the DNA decamers d(CCGGATCCGG) and d(CCGGCGCCGG). ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2002; 58:310-1. [PMID: 11807259 DOI: 10.1107/s0907444901018959] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2001] [Accepted: 11/07/2001] [Indexed: 11/10/2022]
Abstract
The DNA decamers d(CCGGATCCGG) and d(CCGGCGCCGG) have been crystallized for X-ray analysis in order to investigate the effects of changing the two central base pairs of the DNA fragment d(CCGGGACCGG). Previous studies have already demonstrated that the structure of the former DNA fragment contains a DNA Holliday junction. Crystals were obtained at 293 K by the hanging-drop vapour-diffusion technique using the Nucleic Acid Mini Screen. Over a period of two weeks, hexagonal plates appeared. For the DNA fragment d(CCGGATCCGG), the crystals belong to space group P3(1), with unit-cell parameters a = b = 33.54, c = 46.39 A, alpha = beta = 90, gamma = 120 degrees, and diffract to 2.2 A. In the case of the DNA fragment d(CCGGCGCCGG) the crystals belong to the space group C2, with unit-cell parameters a = 65.35, b = 24.07, c = 37.34 A, beta = 109.97 degrees, and diffract to 2.0 A.
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[The mangrove and others vegetation associations in de Gandoca lagoon, Limón, Costa Rica]. REV BIOL TROP 2001; 49 Suppl 2:321-9. [PMID: 15264546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023] Open
Abstract
Six plant associations were identified at Gandoca Lagoon by photointerpretation and field verification: a) mangroves, b) palm trees swamp, and palm trees with Acrostichum aureum and A. danaefolium, c) mixed palm trees, d) very humid tropical rain forest, and e) tropical beach vegetation. The mangroves cover 12.5 ha surrounding the lagoon and extend 2 km up the Gandoca River. Rhizophora mangle (red mangrove) was the dominant species, with Avicennia germinans (black mangrove), Laguncularia racemosa (white mangrove) and Conocarpus erectus (buttonwood) also present. Moving inland the mangroves grade into a tropical rain forest. Gandoca, the largest and best preserved mangrove of Caribbean Costa Rica, tripled its area from 1976 to 2000. Possible causes include sedimentation and the Limón earthquake, which may have subside the lagoon area.
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The structure of an engineered domain-swapped ribonuclease dimer and its implications for the evolution of proteins toward oligomerization. Structure 2001; 9:967-76. [PMID: 11591351 DOI: 10.1016/s0969-2126(01)00659-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND Domain swapping has been proposed as a mechanism that explains the evolution from monomeric to oligomeric proteins. Bovine and human pancreatic ribonucleases are monomers with no biological properties other than their RNA cleavage ability. In contrast, the closely related bovine seminal ribonuclease is a natural domain-swapped dimer that has special biological properties, such as cytotoxicity to tumour cells. Several recombinant ribonuclease variants are domain-swapped dimers, but a structure of this kind has not yet been reported for the human enzyme. RESULTS The crystal structure at 2 A resolution of an engineered ribonuclease variant called PM8 reveals a new kind of domain-swapped dimer, based on the change of N-terminal domains between the two subunits. The swapping is fastened at both hinge peptides by the newly introduced Gln101, involved in two intermolecular hydrogen bonds and in a stacking interaction between residues of different chains. Two antiparallel salt bridges and water-mediated hydrogen bonds complete a new interface between subunits, while the hinge loop becomes organized in a 3(10) helix structure. CONCLUSIONS Proteins capable of domain swapping may quickly evolve toward an oligomeric form. As shown in the present structure, a single residue substitution reinforces the quaternary structure by forming an open interface. An evolutionary advantage derived from the new oligomeric state will fix the mutation and favour others, leading to a more extended complementary dimerization surface, until domain swapping is no longer necessary for dimer formation. The newly engineered swapped dimer reported here follows this hypothetical pathway for the rapid evolution of proteins.
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Abstract
Bacterial conjugation implies a trans-membrane passage of DNA, mediated by proteins encoded in conjugative plasmids. This results in a spread of genetic information, including antibiotic resistance acquisition by pathogens. Special cases of conjugation are trans-kingdom gene transfer from bacteria to plants or fungi, and even bacterial sporulation and cell division. One of the main actors in this process is an integral inner membrane DNA-binding protein, called TrwB in the E. coli R388 conjugative system. It is responsible for coupling the single-strand DNA to be transferred from the donor to the acceptor cell in its complex with other proteins, with a type IV secretion system making up the mating apparatus. The TrwB protomer consists of two domains: a nucleotide-binding domain of alpha/beta topology, similar to RecA and DNA ring helicases, and an all-alpha domain. The quaternary structure reveals an almost spherical homohexamer, strikingly similar to F(1)-ATPase. A central 20 A wide channel traverses the hexamer, thus connecting cytoplasm with periplasm.
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Electrostatic and structural similarity of classical and non-classical lactam compounds. J Comput Aided Mol Des 2001; 15:819-33. [PMID: 11776293 DOI: 10.1023/a:1013123702720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Various electrostatic and structural parameters for a series of classical and non-classical beta-lactams were determined and compared in order to ascertain whether some specific beta-lactams possess antibacterial or beta-lactamase inhibitory properties. The electrostatic parameters obtained, based on the Distributed Multipole Analysis (DMA) of high-quality wavefunctions for the studied structures, suggest that some non-classical beta-lactams effectively inhibit the action of beta-lactamases. As shown in this work, such electrostatic parameters provide much more reliable information about the antibacterial and inhibitory properties of beta-lactams than do structural parameters.
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Abstract
The microtubule cytoskeleton consists of a highly organized network of microtubule polymers bound to their accessory proteins: microtubule-associated proteins, molecular motors, and microtubule-organizing proteins. The microtubule subunits are heterodimers composed of one alpha-tubulin polypeptide and one beta-tubulin polypeptide that should undergo a complex folding processing before they achieve a quaternary structure that will allow their incorporation into the polymer. Due to the extremely high protein concentration that exists at the cell cytoplasm, there are alpha- and beta-tubulin interacting proteins that prevent the unwanted interaction of these polypeptides with the surrounding protein pool during folding, thus allowing microtubule dynamics. Several years ago, the development of a nondenaturing electrophoretic technique made it possible to identify different tubulin intermediate complexes during tubulin biogenesis in vitro. By these means, the cytosolic chaperonin containing TCP-1 (CCT or TriC) and prefoldin have been demonstrated to intervene through tubulin and actin folding. Various other cofactors also identified along the alpha- and beta-tubulin postchaperonin folding route are now known to have additional roles in tubulin biogenesis such as participating in the synthesis, transport, and storage of alpha- and beta-tubulin. The future characterization of the tubulin-binding sites to these proteins, and perhaps other still unknown proteins, will help in the development of chemicals that could interfere with tubulin folding and thus modulating microtubule dynamics. In this paper, current knowledge of the above postchaperonin folding cofactors, which are in fact chaperones involved in tubulin heterodimer quaternary structure achievement, will be reviewed.
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Plasmid transcriptional repressor CopG oligomerises to render helical superstructures unbound and in complexes with oligonucleotides. J Mol Biol 2001; 310:403-17. [PMID: 11428897 DOI: 10.1006/jmbi.2001.4760] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CopG is a 45 amino acid residue transcriptional repressor involved in the copy number control of the streptococcal plasmid pMV158. To do so, it binds to a DNA operator that contains a 13 bp pseudosymmetric DNA element. Binding of CopG to its operator results in repression, at the transcriptional level, of its own synthesis and that of the initiator of replication protein, RepB. Biochemical experiments have shown that CopG co-operatively associates to its target DNA at low protein:DNA ratios, completely protecting four helical turns on the same face of the double helix in both directions from the inverted repeat that constitutes the CopG primary target. This has been correlated with a CopG-mediated DNA bend of about 100 degrees. Here, we show that binding of CopG to DNA fragments containing the inverted repeat just at one end led to nucleation of the protein initiating from the inverted repeat. Nucleation extended to the entire fragment, with CopG-DNA contacts occurring on the same face of the DNA helix. The protein, the prototype for a family of homologous plasmid repressors, displays a homodimeric ribbon-helix-helix arrangement. It polymerises within the unbound crystal to render a continuous right-handed protein superhelix of homodimers, around which a bound double-stranded (ds) DNA could wrap. We have solved the crystal structure of CopG in complex with a 22 bp dsDNA oligonucleotide encompassing the cognate pseudosymmetric element. In the crystal, one protein tetramer binds at one face of the DNA with two parallel beta-ribbons inserted into the major groove. The DNA is bent about 50 degrees under compression of both major and minor grooves. A continuous right-handed complex helix made up mainly by protein-protein and some protein-DNA interactions is observed. The protein-protein interactions involve regions similar to those observed in the oligomerisation of the native crystals and those employed to set up the functional tetramer. A previously solved complex structure of the protein with a 19 bp dsDNA had unveiled a left-handed helical superstructure just made up by DNA interactions.
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