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1.
Osteoarthritis Cartilage ; 27(4): 694-702, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30611906

RESUMEN

OBJECTIVE: Long intergenic non-coding RNAs (lincRNAs) are emerging as key regulators in gene expression; however, little is known about the lincRNA expression changes that occur in osteoarthritis (OA). Here we aimed to define a transcriptome of lncRNAs in OA cartilage, specifically comparing the lincRNA transcriptome of knee and hip cartilage. METHOD: RNA-seq was performed on nucleic acid extracted from hip cartilage from patients undergoing joint replacement surgery because of either OA (n = 10) or because of a neck of femur fracture (NOF; n = 6). After transcript alignment, counts were performed using Salmon and differential expression for ENSEMBL lincRNAs determined using DESeq2. Hip RNA-seq lincRNA expression was compared to a knee dataset (ArrayExpress; E-MTAB-4304). ChIP-seq data from ENCODE was used to determine whether lincRNAs were associated with promoters (plncRNA) or unidirectional enhancer-like regulatory elements (elncRNAs). RESULTS: Our analysis of the hip transcriptome identified 1692 expressed Transcripts Per Million (TPM ≥1) Ensembl lincRNAs, of which 198 were significantly (FDR ≤0.05) differentially expressed in OA vs normal (NOF) cartilage. Similar analysis of knee cartilage transcriptome identified 648 Emsembl lincRNAs with 93 significantly (FDR ≤0.05) differentially expressed in intact vs damaged cartilage. In total, 1834 lincRNAs were expressed in both hip and knee cartilage, with a highly significant correlation in expression between the two cartilages. CONCLUSION: This is the first study to use RNA-seq to map and compare the lincRNA transcriptomes of hip and knee cartilage. We propose that lincRNAs expressed selectively in cartilage, or showing differential expression in OA, will play a role in cartilage homoeostasis.


Asunto(s)
Cartílago Articular/metabolismo , Regulación de la Expresión Génica , Osteoartritis de la Cadera/genética , Osteoartritis de la Rodilla/genética , ARN Largo no Codificante/genética , Transcriptoma/genética , Anciano , Biomarcadores/metabolismo , Cartílago Articular/diagnóstico por imagen , Femenino , Humanos , Masculino , Osteoartritis de la Cadera/diagnóstico , Osteoartritis de la Cadera/metabolismo , Osteoartritis de la Rodilla/diagnóstico , Osteoartritis de la Rodilla/metabolismo , ARN/genética , ARN Largo no Codificante/biosíntesis
2.
J Phys Chem A ; 121(32): 6054-6062, 2017 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-28737914

RESUMEN

1,4,7-Triazacyclononane-1,4,7-triacetic acid (NOTA) is a key bifunctional chelator utilized for the complexation of metal ions in radiopharmaceutical applications; the ability of these chelators depends on the strength of their binding with ions. The focus of the present work is to evaluate the complexation of Cu2+, Ga3+, Sc3+, and In3+ radiometal ions with NOTA using density functional theory (B3LYP functional) and 6-311+G(2d,2p)/DGDZVP basis sets. The significant role of ion-water interactions in the chelation interaction energies in solution reflects the competition between ion-water and NOTA-ion interaction in the chelation process. There is reasonable agreement between experimental and theoretical binding constants, geometries, and 1H NMR chemical shifts. Chelation interaction energies, Gibbs free energies, and entropies in solution show that the NOTA-Ga3+ and NOTA-Cu2+ are the most and least stable complexes, respectively. The natural atomic charges and second order perturbation analysis reveal charge transfer between NOTA and radiometal ions. The theoretical 1H NMR chemical shifts of NOTA are in good agreement with experiment; these values are influenced by the presence of the ions, which have a deshielding effect on the protons of NOTA. Global scalar properties such as EHOMO/ELUMO, ΔELUMO-HOMO, and chemical hardness/softness confirm that the NOTA-Cu2+ complex, which has a singly occupied molecular orbital, has the lowest ΔELUMO-HOMO value, the least chemical hardness, and the highest chemical softness. The significant variation of the hardness and ΔELUMO-HOMO values of the complexes can be attributed to the different positions of the metal ions on the periodic table. This study affirms that, among the radiometal ions, Ga3+ can be used to effectively radiolabel NOTA chelator for radiopharmaceutical usage as it binds most stably with NOTA.

3.
Arch Virol ; 159(12): 3463-5, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25252813

RESUMEN

The 9573-nucleotide genome of a potyvirus was sequenced from a Coriandrum sativum plant from India with viral symptoms. On analysis, this virus was shown to have greater than 85 % nucleotide sequence identity to vanilla distortion mosaic virus (VDMV). Analysis of the putative coat protein sequence confirmed that this virus was in fact VDMV, with greater than 91 % amino acid sequence identity. The genome appears to encode a 3083-amino-acid polyprotein potentially cleaved into the 10 mature proteins expected in potyviruses. Phylogenetic analysis confirmed that VDMV is a distinct but ungrouped member of the genus Potyvirus.


Asunto(s)
Coriandrum/virología , Genoma Viral , Potyvirus/genética , ARN Viral/genética , Análisis de Secuencia de ADN , Análisis por Conglomerados , India , Datos de Secuencia Molecular , Filogenia , Enfermedades de las Plantas/virología , Poliproteínas/genética , Potyvirus/clasificación , Potyvirus/aislamiento & purificación , Homología de Secuencia de Aminoácido , Proteínas Virales/genética
4.
Phys Chem Chem Phys ; 15(12): 4341-54, 2013 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-23412381

RESUMEN

Density functional theory (DFT) calculations using the B3LYP and ωB97XD functionals and Møller-Plesset (MP2) calculations have been used to determine the energy of insertion of seven molecules (CO2, N2, O2, CO, CH4, He and H2O) into two sizes of polyhedral oligomeric silsesquioxane (POSS) cages, T10 and T12. Geometry optimization results of each molecule inserted into the center of the POSS cage and transition-energy searches of the molecules in the largest face of both T10 and T12 (identified as the Si5 face) are discussed. The main factors that affect the energy of a molecule in a particular POSS cage are the size (number of atoms) and shape of the POSS cage and the strength of dispersion and electrostatic interactions. The largest of the molecules, CO2 and CH4, have the largest interaction energies within the center and the face of the T10 and T12 cages. Interaction energies for the diatomic molecules increase in the order H2 < O2 < N2 ∼ CO and differences between interaction energies can be attributed, in part, to differences in electron transfer between the cage and molecule. Electrostatic interactions also play a significant role in determining the interaction energy. For example, H2 and He are only slightly charged when inside the POSS cages, providing little repulsive or attractive interactions, while polar CO provides significant repulsive interaction. In the case of water, the interaction energies are low because of hydrogen bonding between the water hydrogen atoms and the POSS oxygen atoms. The interaction energies of the absorbates at the center of T12 are typically smaller than for T10 due to the larger cavity size of T12. The Si5 face has the same basic structure for both T10 and T12 cages and, consequently, the interaction energies of the absorbate molecules at the face are similar. Interaction energies obtained using MP2 calculations are lower than those obtained from DFT calculations depending on the choice of the functional. For example, use of the ωB97XD functional that treats dispersion interactions more completely than the B3LYP functional, produces values closer to the MP2 values. These results, therefore, suggest that dispersion is important in the interaction between small molecules and POSS cages.

5.
J Synchrotron Radiat ; 18(Pt 2): 257-65, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21335914

RESUMEN

A method for comparing pixelated density profiles (e.g. obtained from molecular dynamics or other computational techniques) with experimental X-ray reflectivity data both directly and quantitatively is described. The conditions under which such a comparison can be made quantitatively (e.g. with errors <1%) are determined theoretically by comparing calculated structure factors for an intrinsic continuous density profile with those obtained from density profiles that have been binned into regular spatial increments. The accuracy of the X-ray reflectivity calculations for binned density profiles is defined in terms of the inter-relationships between resolution of the X-ray reflectivity data (i.e. its range in momentum transfer), the chosen bin size and the width of the intrinsic density profile. These factors play a similar role in the application of any structure-factor calculations that involve the use of pixelated density profiles, such as those obtained from iterative phasing algorithms for inverting structures from X-ray reflectivity and coherent diffraction imaging data. Finally, it is shown how simulations of a quartz-water interface can be embedded into an exact description of the `bulk' phases (including the substrate crystal and the fluid water, below and above the actual interface) to quantitatively reproduce the experimental reflectivity data of a solid-liquid interface.


Asunto(s)
Simulación de Dinámica Molecular , Difracción de Rayos X/métodos , Modelos Moleculares , Cuarzo/química , Propiedades de Superficie , Agua/química , Rayos X
6.
Langmuir ; 27(14): 8700-9, 2011 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-21648451

RESUMEN

Two different terminations of the (1010) surface of quartz (α and ß) interacting with water are simulated by classical (CMD) (using two different force fields) and ab initio molecular dynamics (AIMD) and compared with previously published X-ray reflectivity (XR) experiments. Radial distribution functions between hydroxyl and water show good agreement between AIMD and CMD using the ClayFF force field for both terminations. The Lopes et al. (Lopes, P. E. M.; Murashov, V.; Tazi, M.; Demchuk, E.; MacKerell, A. D. J. Phys. Chem. B2006, 110, 2782-2792) force field (LFF), however, underestimates the extent of hydroxyl-water hydrogen bonding. The ß termination is found to contain hydroxyl-hydroxyl hydrogen bonds; the quartz surface hydroxyl hydrogens and oxygens that hydrogen bond with each other exhibit greatly reduced hydrogen bonding to water. Conversely, the hydroxyl hydrogen and oxygens that are not hydrogen bonded to other surface hydroxyls but are connected to those that are show a considerable amount of hydrogen bonding to water. The electron density distribution of an annealed surface of quartz (1010) obtained by XR is in qualitative agreement with electron densities calculated by CMD and AIMD. In all simulation methods, the interfacial water peak appears farther from the surface than observed by XR. Agreement among AIMD, LFF, and XR is observed for the relaxation of the near-surface atoms; however, ClayFF shows a larger discrepancy. Overall, results show that for both terminations of (1010), LFF treats the near-surface structure more accurately whereas ClayFF treats the interfacial water structure more accurately. It is shown that the number of hydroxyl and water hydrogen bonds to the bridging Si-O-Si oxygens connecting the surface silica groups to the rest of the crystal is much greater for the α than the ß termination. It is suggested that this may play a role in the greater resistance to dissolution of the ß termination than that of the α termination.


Asunto(s)
Simulación de Dinámica Molecular , Cuarzo/química , Agua/química , Conformación Molecular , Teoría Cuántica , Propiedades de Superficie
7.
Antimicrob Agents Chemother ; 54(6): 2365-70, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20308381

RESUMEN

Small-molecule hepatitis C virus (HCV) NS3 protease inhibitors such as boceprevir (SCH 503034) have been shown to have antiviral activity when they are used as monotherapy and in combination with pegylated alpha interferon and ribavirin in clinical trials. Improvements in inhibitor potency and pharmacokinetic properties offer opportunities to increase drug exposure and to further increase the sustained virological response. Exploration of the structure-activity relationships of ketoamide inhibitors related to boceprevir has led to the discovery of SCH 900518, a novel ketoamide protease inhibitor which forms a reversible covalent bond with the active-site serine. It has an overall inhibition constant (K*(i)) of 7 nM and a dissociation half-life of 1 to 2 h. SCH 900518 inhibited replicon RNA at a 90% effective concentration (EC(90)) of 40 nM. In biochemical assays, SCH 900518 was active against proteases of genotypes 1 to 3. A 2-week treatment with 5x EC(90) of the inhibitor reduced the replicon RNA level by 3 log units. Selection of replicon cells with SCH 900518 resulted in the outgrowth of several resistant mutants (with the T54A/S and A156S/T/V mutations). Cross-resistance studies demonstrated that the majority of mutations for resistance to boceprevir and telaprevir caused similar fold losses of activity against all three inhibitors; however, SCH 900518 retained more activity against these mutants due to its higher intrinsic potency. Combination treatment with alpha interferon enhanced the inhibition of replicon RNA and suppressed the emergence of resistant replicon colonies, supporting the use of SCH 900518-pegylated alpha interferon combination therapy in the clinic. In summary, the results of the preclinical characterization of the antiviral activity of SCH 900518 support its evaluation in clinical studies.


Asunto(s)
Antivirales/farmacología , Dipéptidos/farmacología , Hepacivirus/efectos de los fármacos , Hepacivirus/enzimología , Inhibidores de Proteasas/farmacología , Sulfonas/farmacología , Proteínas no Estructurales Virales/antagonistas & inhibidores , Antivirales/administración & dosificación , Antivirales/química , Ciclopropanos , Dipéptidos/administración & dosificación , Dipéptidos/química , Descubrimiento de Drogas , Evaluación Preclínica de Medicamentos , Farmacorresistencia Viral/genética , Genotipo , Hepacivirus/genética , Humanos , Técnicas In Vitro , Interferón alfa-2 , Interferón-alfa/administración & dosificación , Cinética , Leucina/análogos & derivados , Mutación , Prolina/análogos & derivados , Prolina/farmacología , Inhibidores de Proteasas/administración & dosificación , Inhibidores de Proteasas/química , Proteínas Recombinantes , Replicón/efectos de los fármacos , Sulfonas/administración & dosificación , Sulfonas/química , Urea
8.
J Med Entomol ; 47(5): 798-804, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20939374

RESUMEN

The American house dust mite, Dermatophagoidesfarinae Hughes, and European house dust mite, Dermatophagoides pteronyssinus Trouessart, are major pests of medical importance throughout the developed world, causing atopic diseases such as asthma, rhinitis, and atopic dermatitis. Previous studies in our laboratory have shown that the behavioral responses of house dust mites toward volatiles from food sources could be assessed using a Y-tube olfactometer assay. The current study used this Y-tube assay to investigate house dust mite pheromones. A hexane extract of D.farinae, along with fractions of the extract prepared by microscale liquid chromatography over Florisil, were tested for behavioral activity. One of the chromatographic fractions was shown to be significantly attractive (P < 0.05) for D. farinae, compared with a solvent control. Coupled gas chromatography-mass spectrometry analysis of this behaviorally active fraction indicated that neryl or geranyl formate was the major component. Peak enhancement by gas chromatography, using authentic samples of the neryl and geranyl isomers prepared in high purity by chemical synthesis, confirmed the identity of the major peak as neryl formate. In Y-tube assays, male and female D. farinae and D. pteronyssinus both were significantly attracted to synthetic neryl formate at doses of 100 and 10 ng, respectively (P < 0.05). No significant differences were found for D. farinae and D. pteronyssinus when synthetic neryl formate and house dust mite extracts containing natural neryl formate were tested at the same level. Dynamic headspace collection of D. farinae and D. pteronyssinus colonies showed that neryl formate was released as a volatile organic compound by both species. Our study shows that neryl formate is an aggregation pheromone for D. farinae and D. pteronyssinus, and has the potential to be used as part of a novel lure-and-kill system for house dust mite control.


Asunto(s)
Dermatophagoides farinae/fisiología , Dermatophagoides pteronyssinus/fisiología , Formiatos/metabolismo , Feromonas/fisiología , Terpenos/metabolismo , Animales , Conducta Animal/fisiología , Femenino , Masculino
9.
Psychon Bull Rev ; 27(1): 78-85, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31848908

RESUMEN

The extent to which aesthetic preferences are 'innate' has been highly debated (Reber, Schwarz, & Winkielman, Personality and Social Psychology Review, 8(4), 364-382, 2004). For some types of visual stimuli infants look longer at those that adults prefer. It is unclear whether this is also the case for colour. A lack of relationship in prior studies between how long infants look at different colours and how much adults like those colours might be accounted for by stimulus limitations. For example, stimuli may have been too desaturated for infant vision. In the current study, using saturated colours more suitable for infants, we aim to quantify the relationship between infant looking and adult preference for colour. We take infant looking times at multiple hues from a study of infant colour categorization (Skelton, Catchpole, Abbott, Bosten, & Franklin, Proceedings of the National Academy of Sciences of the United States of America, 114(21), 5545-5550, 2017) and then measure adult preferences and compare these to infant looking. When colours are highly saturated, infants look longer at colours that adults prefer. Both infant looking time and adult preference are greatest for blue hues and are least for green-yellow. Infant looking and adult preference can be partly summarized by activation of the blue-yellow dimension in the early encoding of human colour vision. These findings suggest that colour preference is at least partially rooted in the sensory mechanisms of colour vision, and more broadly that aesthetic judgements may in part be due to underlying sensory biases.


Asunto(s)
Visión de Colores , Color , Comportamiento del Consumidor , Adolescente , Percepción de Color , Estética , Femenino , Humanos , Lactante , Juicio , Masculino , Adulto Joven
10.
J Med Entomol ; 44(2): 367-71, 2007 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17427710

RESUMEN

Dermatophagoides farinae Hughes (Acari: Epidermoptidae), the American house dust mite, and Tyrophagus putrescentiae (Schrank) (Acari: Acaridae), the mold mite, are medically and economically important but controlling them has proved difficult, and recolonization is commonplace. Their behavioral responses to different sources of volatile chemicals are still not fully elucidated. For the first time, the Y-tube olfactometer, which is an enclosed bioassay to resolve responses to test and control volatiles, has been successfully used with these mites. Mites were tested individually, and both T. putrescentiae and D. farinae responded to food volatiles. Y-tube olfactometers may be used to test for potential semiochemicals, thereby increasing knowledge of our behavior of astigmatic mites.


Asunto(s)
Acaridae/fisiología , Conducta Animal/fisiología , Dermatophagoides farinae/fisiología , Odorantes , Olfato/fisiología , Alimentación Animal , Animales , Bioensayo , Humedad , Factores de Tiempo , Zoología/instrumentación , Zoología/métodos
11.
J Mol Graph Model ; 76: 70-76, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28711759

RESUMEN

1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetracetic acid (DOTA) is an important chelator for radiolabeling of pharmaceuticals. The ability of alkali metals found in the body to complex with DOTA and compete with radio metal ions can alter the radiolabeling process. Non-covalent interactions between DOTA complexed with alkali metals Li+, Na+, K+ and Rb+, are investigated with density functional theory using B3LYP and ωB97XD functionals. Conformational possibilities of DOTA were explored with a varying number of carboxylic pendant arms of DOTA in close proximity to the ions. It is found that the case in which four arms of DOTA are interacting with ions is more stable than other conformations. The objective of this study is to explore the electronic structure properties upon complexation of alkali metals Li+ Na+, K+ and Rb+ with a DOTA chelator. Interaction energies, relaxation energies, entropies, Gibbs free energies and enthalpies show that the stability of DOTA, complexed with alkali metals decreases down the group of the periodic table. Implicit water solvation affects the complexation of DOTA-ions leading to decreases in the stability of the complexes. NBO analysis through the natural population charges and the second order perturbation theory, revealed a charge transfer between DOTA and alkali metals. Conceptual DFT-based properties such as HOMO/LUMO energies, ΔEHOMO-LUMO and chemical hardness and softness indicated a decrease in the chemical stability of DOTA-alkali metal complexes down the alkali metal series. This study serves as a guide to researchers in the field of organometallic chelators, particularly, radiopharmaceuticals in finding the efficient optimal match between chelators and various metal ions.


Asunto(s)
Quelantes/química , Compuestos Heterocíclicos con 1 Anillo/química , Iones/química , Metales Alcalinos/química , Compuestos Organometálicos/química , Teoría Cuántica , Termodinámica , Agua/química
12.
Philos Trans A Math Phys Eng Sci ; 375(2095)2017 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-28461437

RESUMEN

If targets to reduce greenhouse gas emissions and thereby tackle climate change are to be achieved, it will be necessary to reduce both embodied energy costs (e.g. in terms of producing and manufacturing the products and services that society consumes) and operational energy costs. Reducing the number of purchases that people regret could be a first step in changing the overall dynamic of consumption patterns. This research looks at some potentially adverse effects of consumption on well-being (e.g. negative emotions), applying social practice theory to give insights into why people make purchases that they feel negatively about. This paper draws from: (i) findings of a national survey of over 2000 respondents which found that 53% of adults had reported regretting purchasing an electrical device at some point, and that 23% regretted making such a purchase within the past year; and (ii) a series of walking interviews around people's homes that provide detailed insights into the nature and extent of regretted purchases of electrical goods (e.g. resentment at built-in obsolescence, frustration at the pace of technological change). By combining the qualitative and quantitative data, we develop a typology of regretted consumption and explore the underlying factors that lead to such purchases. The paper concludes with a discussion of the policy implications of this research.This article is part of the themed issue 'Material demand reduction'.

13.
Structure ; 5(7): 961-78, 1997 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-9261087

RESUMEN

BACKGROUND: Polioviruses are human pathogens and the causative agents of poliomyelitis. Polioviruses are icosahedral single-stranded RNA viruses, which belong to the picornavirus family, and occur as three distinct serotypes. All three serotypes of poliovirus can infect primates, but only type 2 can infect mice. The crystal structures of a type 1 and a type 3 poliovirus are already known. Structural studies of poliovirus type 2 Lansing (PV2L) were initiated to try to enhance our understanding of the differences in host range specificity, antigenicity and receptor binding among the three serotypes of poliovirus. RESULTS: The crystal structure of the mouse neurovirulent PV2L complexed with a potent antiviral agent, SCH48973, was determined at 2.9 A resolution. Structural differences among the three poliovirus serotypes occur primarily in the loop regions of the viral coat proteins (VPs), most notably in the loops of VP1 that cluster near the fivefold axes of the capsid, where the BC loop of PV2L is disordered. Unlike other known structures of enteroviruses, the entire polypeptide chain of PV2L VP4 is visible in the electron density and RNA bases are observed stacking with conserved aromatic residues (Tyr4020 and Phe4046) of VP4. The broad-spectrum antiviral agent SCH48973 is observed binding in a pocket within the beta-barrel of VP1, in approximately the same location that natural 'pocket factors' bind to polioviruses. SCH48973 forms predominantly hydrophobic interactions with the pocket residues. CONCLUSIONS: Some of the conformational changes required for infectivity and involved in the control of capsid stability and neurovirulence in mice may occur in the vicinity of the fivefold axis of the poliovirus, where there are significant structural differences among the three poliovirus serotypes in the surface exposed loops of VP1 (BC, DE, and HI). A surface depression is located at the fivefold axis of PV2L that is not present in the other two poliovirus serotypes. The observed interaction of RNA with VP4 supports the observation that loss of VP4 ultimately leads to the loss of viral RNA. A model is proposed that suggests dual involvement of the virion fivefold and pseudo-threefold axes in receptor-mediated initiation of infection by picornaviruses.


Asunto(s)
Antivirales/química , Éteres Fenílicos/química , Theilovirus/química , Adaptación Fisiológica , Animales , Antivirales/farmacología , Calcio/química , Calcio/metabolismo , Cristalización , Cristalografía por Rayos X , Éteres Difenilos Halogenados , Humanos , Ratones , Modelos Biológicos , Ácidos Mirísticos/química , Ácidos Mirísticos/metabolismo , Éteres Fenílicos/farmacología , Picornaviridae/química , Picornaviridae/metabolismo , Hidrocarburos Policíclicos Aromáticos/química , Hidrocarburos Policíclicos Aromáticos/metabolismo , Conformación Proteica , Estructura Terciaria de Proteína , ARN Viral/química , ARN Viral/metabolismo , Alineación de Secuencia , Homología de Secuencia de Aminoácido , Serotipificación , Relación Estructura-Actividad , Temperatura , Theilovirus/clasificación , Theilovirus/efectos de los fármacos , Replicación Viral
14.
J Biomol Struct Dyn ; 34(3): 529-39, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26046587

RESUMEN

All-atom molecular dynamics is used to investigate the transport of Na(+) across a 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayer facilitated by a diazacrown hydraphile. Specifically, the free energy of Na(+) passing through the bilayer is calculated using the adaptive biasing force method to study the free energy associated with the increase in Na(+) transport in the presence of the hydraphile molecule. The results show that water interaction greatly influences Na(+) transport through the lipid bilayer as water is pulled through the bilayer with Na(+) forming a water channel. The hydraphile causes a reduction in the free energy barrier for the transport of Na(+) through the head group part of the lipid bilayer since it complexes the Na(+) reducing the necessity for water to be complexed and, therefore, dragged through with Na(+), an energetically unfavorable process. The free energy associated with Na(+) being desolvated within the bilayer is significantly decreased in the presence of the hydraphile molecule; the hydraphile increases the number of solvation states of Na(+) that can be adopted, and this increase in the number of available configurations provides an entropic explanation for the success of the hydraphile.


Asunto(s)
Membrana Dobles de Lípidos/química , Simulación de Dinámica Molecular , Canales de Sodio/química , Interacciones Hidrofóbicas e Hidrofílicas , Iones/química , Conformación Molecular , Teoría Cuántica , Sodio/química , Solventes/química , Agua/química
15.
J Virol Methods ; 123(1): 73-80, 2005 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-15582701

RESUMEN

Real-time RT-PCR (TaqMan) assays were developed for the specific detection of Beet necrotic yellow vein virus (BNYVV). The two assays designed were a broad-spectrum one that detected RNA 2 from all types and a second designed to detect types containing RNA 5. The assays were validated against a range of different isolates from Europe and the Far East. These real-time assays were compared to a conventional RT-PCR assay for the detection of RNA 5. Sensitivity comparisons showed that for the detection of RNA 5, TaqMan was 10,000 times more sensitive than the conventional RT-PCR assay. Further improvements were made to the test procedure by using post-ELISA virus release (VR), as an alternative to RNA extraction. This significantly increased the speed of processing samples and reduced the staff input required, allowing the TaqMan assay to be used routinely as part of an annual survey of UK field samples.


Asunto(s)
Beta vulgaris/virología , Virus ARN/aislamiento & purificación , ARN Viral/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Enfermedades de las Plantas/virología , Virus ARN/genética , ARN Viral/aislamiento & purificación , Sensibilidad y Especificidad , Polimerasa Taq/metabolismo
16.
FEBS Lett ; 509(3): 355-60, 2001 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-11749955

RESUMEN

The substrate specificity of the thermophilic beta-glycosidase (lacS) from the archaeon Sulfolobus solfataricus (SSbetaG), a member of the glycohydrolase family 1, has been analysed at a molecular level using predictions from known protein sequences and structures and through site-directed mutagenesis. Three critical residues were identified and mutated to create catalysts with altered and broadened specificities for use in glycoside synthesis. The wild-type (WT) and mutated sequences were expressed as recombinant fusion proteins in Escherichia coli, with an added His(6)-tag to allow one-step chromatographic purification. Consistent with side-chain orientation towards OH-6, the single Met439-->Cys mutation enhances D-xylosidase specificity 4.7-fold and decreases D-fucosidase activity 2-fold without greatly altering its activity towards other D-glycoside substrates. Glu432-->Cys and Trp433-->Cys mutations directed towards OH-4 and -3, respectively, more dramatically impair glucose (Glc), galactose (Gal), fucose specificity than for other glycosides, resulting in two glycosidases with greatly broadened substrate specificities. These include the first examples of stereospecificity tailoring in glycosidases (e.g. WT-->W433C, k(cat)/K(M) (Gal):k(cat)/K(M) (mannose (Man))=29.4:1-->1.2:1). The robustness and high utility of these broad specificity SSbetaG mutants in parallel synthesis were demonstrated by the formation of libraries of beta-glycosides of Glc, Gal, xylose, Man in one-pot preparations at 50 degrees C in the presence of organic solvents, that could not be performed by SSbetaG-WT.


Asunto(s)
Glucosidasas/química , Glucosidasas/metabolismo , Sulfolobus/enzimología , Secuencia de Aminoácidos , Sitios de Unión/genética , Catálisis , Glucosidasas/genética , Ácido Glutámico/genética , Ácido Glutámico/metabolismo , Cinética , Metionina/genética , Metionina/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Conformación Proteica , Especificidad por Sustrato
17.
Antiviral Res ; 32(2): 71-9, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8891166

RESUMEN

SCH 47802 and its derivatives are potent inhibitors of enteroviruses in vitro. The IC50 for SCH 47802 ranges from 0.03 to 10 micrograms/ml when tested against a spectrum of enteroviruses in plaque reduction assays. The compounds have in vitro therapeutic indices of at least 81 based on viral cytopathic effect (CPE) assays. The in vitro activity of SCH 47802 translates into in vivo activity in the murine model of poliovirus encephalitis. In an oral dosing regimen, SCH 47802 protects mice from mortality at 60 mg/kg per day. Consistent with the in vivo efficacy, pharmacokinetic analyses after oral dosing with SCH 47802 demonstrate serum levels of the compound above the in vitro IC50 for poliovirus for at least 4 h. SCH 47802 and its active analogs stabilize poliovirus to thermal inactivation indicating that the compounds bind to the virus capsid. Mechanistic studies with poliovirus indicate that SCH 47802 acts early in viral infection. This series of molecules represents potential candidates for the treatment of human enterovirus infections.


Asunto(s)
Antivirales/farmacología , Clorobencenos/farmacología , Picornaviridae/efectos de los fármacos , Animales , Antivirales/farmacocinética , Cápside/efectos de los fármacos , Línea Celular , Clorobencenos/química , Clorobencenos/farmacocinética , Encefalitis Viral/tratamiento farmacológico , Células HeLa , Calor , Humanos , Ratones , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Infecciones por Picornaviridae/tratamiento farmacológico
18.
Antiviral Res ; 35(3): 139-46, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9298753

RESUMEN

SCH 43478 and analogs are a class of non-nucleoside antiviral agents that have potent and selective activity against herpes simplex virus type 2 (HSV-2). The IC50 for these compounds in plaque reduction analysis using Vero cells ranges from 0.8 to 2.0 microg/ml. All compounds have a LC50 > 100 microg/ml in cytotoxicity analysis. Mechanism of action studies suggest that these molecules have an effect on the transactivation of viral immediate early (alpha) gene expression. Time of addition studies indicate that antiviral activity of these analogs is limited to the initial 2-3 h after infection and is not due to inhibition of viral adsorption or penetration. Analysis of HSV protein expression demonstrates that SCH 49286 inhibits the accumulation of viral immediate early (alpha) gene products. SCH 43478 demonstrates statistically significant efficacy (P < 0.05) in the guinea pig genital model of HSV infection. Following subcutaneous administration in a therapeutic treatment regimen, SCH 43478 (90 mg/kg/day) is efficacious in reducing the number and severity of lesions and the neurological complications of acute HSV infection. Thus, SCH 43478 and analogs are anti-herpesvirus agents with a unique mechanism of action.


Asunto(s)
Antivirales/farmacología , Herpesvirus Humano 2/efectos de los fármacos , Pirazoles/farmacología , Quinolinas/farmacología , Adsorción , Animales , Antivirales/administración & dosificación , Antivirales/química , Células Cultivadas , Chlorocebus aethiops , Femenino , Fibroblastos , Cobayas , Células HeLa , Herpes Genital/tratamiento farmacológico , Herpes Genital/virología , Herpesvirus Humano 2/metabolismo , Humanos , Proteínas Inmediatas-Precoces/biosíntesis , Inyecciones Subcutáneas , Cinética , Pirazoles/química , Quinolinas/química , Células Vero
19.
Obstet Gynecol ; 90(4 Pt 1): 538-41, 1997 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9380312

RESUMEN

OBJECTIVE: To determine patterns of use of cord blood gas analysis in two institutions in Portland, Maine; to determine which factors, if any, predicted use of the test; and to evaluate compliance with ACOG guidelines. METHODS: Billing data were used from 3166 deliveries during 1994 in the two hospitals to find deliveries in which the test was performed. We merged billing data with birth certificate data to examine factors associated with the test's use. Finally, we compared its use in our community with recently updated ACOG guidelines. RESULTS: There was a 20-fold difference in the test's use between institutions (P < .001). The test was performed in 49% of all births at the tertiary care center and 2.5% of births at the community hospital. Many maternal and neonatal factors were linked to use of the test, but delivery system factors, in particular, the institution, were the strongest predictors of the test's use, even controlling for confounding factors between hospitals. There was little adherence to ACOG guidelines, with 97% of the tests being performed in situations in which ACOG's recommendations did not support use of the analysis. CONCLUSION: Current use of cord blood gas analysis in our community is not consistent with guidelines or cost-effective use of resources; the institutional factors that determine excess use should be examined and modified.


Asunto(s)
Análisis de los Gases de la Sangre/estadística & datos numéricos , Sangre Fetal , Femenino , Predicción , Adhesión a Directriz , Humanos , Recién Nacido , Masculino
20.
Br J Gen Pract ; 46(404): 153-6, 1996 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-8731620

RESUMEN

BACKGROUND: Low back pain is a common and persistent problem. Research studies seeking to improve the quality of management of this condition have tended to ignore the opinions of patients. There is a growing acceptance of the importance of taking patients' views into account in developing management and educational programmes for a variety of conditions. AIM: This study set out to elicit the views of patients concerning low back pain and its management in general practice. METHOD: Fifty-two in-depth interviews were conducted with patients selected from a broad range of 12 general practices. RESULTS: Analysis of the interviews identified seven themes relating to: quality of life, prognosis, secondary prevention, help-seeking behaviour, explanation of underlying pathology, satisfaction with general practitioner management, and complementary therapy. Different patient viewpoints or perspectives were expressed within each of these themes. Patients adapted to the progress of their low back pain and were not seeking a 'magical cure' from either conventional or complementary therapies. CONCLUSION: Patients' views on low back pain are heterogeneous. The dissatisfaction expressed with medical explanations for the pain may be related to superficial clinical management and the constraints of general practice. Good management of low back pain needs to take patients' complex views of the condition into account.


Asunto(s)
Dolor de la Región Lumbar/terapia , Satisfacción del Paciente , Adolescente , Adulto , Anciano , Actitud Frente a la Salud , Medicina Familiar y Comunitaria , Femenino , Humanos , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud , Relaciones Médico-Paciente
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