Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 14 de 14
Filtrar
1.
J Clin Virol ; 171: 105659, 2024 04.
Artigo em Inglês | MEDLINE | ID: mdl-38430669

RESUMO

Anorectal and oropharyngeal exposures are implicated in sexual transmission of mpox, but authorized assays in the United States are only validated with cutaneous lesion swabs. Diagnostic assays for anorectal and oropharyngeal swabs are needed to address potential future outbreaks. The Cepheid Xpert® Mpox is the first point-of-care assay to receive FDA emergency use authorization in the United States and would be a valuable tool for evaluating these sample types. Our exploratory study demonstrates 100 % positive agreement with our in-house PCR assay for natural positive anorectal and oropharyngeal specimens and 92 % sensitivity with low-positive spiked specimens. The Xpert® assay detected viral DNA in specimens not detected by our reference PCR assay from four participants with mpox DNA at other sites, suggesting it may be more sensitive at low viral loads. In conclusion, the validation of the Xpert® for oropharyngeal and anorectal sample types can be rapidly achieved if clinical need returns and prospective samples become available.


Assuntos
Mpox , Humanos , Estados Unidos , Estudos Prospectivos , Sensibilidade e Especificidade , Manejo de Espécimes , Reação em Cadeia da Polimerase
2.
Sci Adv ; 8(37): eabn1731, 2022 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-36112676

RESUMO

Voltage-gated K+ (Kv) channels mediate the flow of K+ across the cell membrane by regulating the conductive state of their activation gate (AG). Several Kv channels display slow C-type inactivation, a process whereby their selectivity filter (SF) becomes less or nonconductive. It has been proposed that, in the fast inactivation-removed Shaker-IR channel, the W434F mutation epitomizes the C-type inactivated state because it functionally accelerates this process. By introducing another pore mutation that prevents AG closure, P475D, we found a way to record ionic currents of the Shaker-IR-W434F-P475D mutant at hyperpolarized membrane potentials as the W434F-mutant SF recovers from its inactivated state. This W434F conductive state lost its high K+ over Na+ selectivity, and even NMDG+ can permeate, features not observed in a wild-type SF. This indicates that, at least during recovery from inactivation, the W434F-mutant SF transitions to a widened and noncationic specific conformation.

3.
Toxicon ; 120: 57-60, 2016 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-27475861

RESUMO

The marine polycyclic-ether toxin gambierol and 1-butanol (n-alkanol) inhibit Shaker-type Kv channels by interfering with the gating machinery. Competition experiments indicated that both compounds do not share an overlapping binding site but gambierol is able to affect 1-butanol affinity for Shaker through an allosteric effect. Furthermore, the Shaker-P475A mutant, which inverses 1-butanol effect, is inhibited by gambierol with nM affinity. Thus, gambierol and 1-butanol inhibit Shaker-type Kv channels via distinct parts of the gating machinery.


Assuntos
1-Butanol/toxicidade , Ciguatoxinas/toxicidade , Bloqueadores dos Canais de Potássio/toxicidade , Superfamília Shaker de Canais de Potássio/antagonistas & inibidores , Sítios de Ligação , Ativação do Canal Iônico
4.
Sci Rep ; 5: 17402, 2015 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-26616025

RESUMO

Alkanols are small aliphatic compounds that inhibit voltage-gated K(+) (K(v)) channels through a yet unresolved gating mechanism. K(v) channels detect changes in the membrane potential with their voltage-sensing domains (VSDs) that reorient and generate a transient gating current. Both 1-Butanol (1-BuOH) and 1-Hexanol (1-HeOH) inhibited the ionic currents of the Shaker K(v) channel in a concentration dependent manner with an IC50 value of approximately 50 mM and 3 mM, respectively. Using the non-conducting Shaker-W434F mutant, we found that both alkanols immobilized approximately 10% of the gating charge and accelerated the deactivating gating currents simultaneously with ionic current inhibition. Thus, alkanols prevent the final VSD movement(s) that is associated with channel gate opening. Applying 1-BuOH and 1-HeOH to the Shaker-P475A mutant, in which the final gating transition is isolated from earlier VSD movements, strengthened that neither alkanol affected the early VSD movements. Drug competition experiments showed that alkanols do not share the binding site of 4-aminopyridine, a drug that exerts a similar effect at the gating current level. Thus, alkanols inhibit Shaker-type K(v) channels via a unique gating modifying mechanism that stabilizes the channel in its non-conducting activated state.


Assuntos
Álcoois/farmacologia , Ativação do Canal Iônico/efeitos dos fármacos , Bloqueadores dos Canais de Potássio/farmacologia , Canais de Potássio de Abertura Dependente da Tensão da Membrana/antagonistas & inibidores , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Animais , Sítios de Ligação , Linhagem Celular , Hexanóis/farmacologia , Humanos , Cinética , Potenciais da Membrana/efeitos dos fármacos , Mutação , Canais de Potássio de Abertura Dependente da Tensão da Membrana/química , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genética , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Superfamília Shaker de Canais de Potássio/antagonistas & inibidores , Superfamília Shaker de Canais de Potássio/química , Superfamília Shaker de Canais de Potássio/genética , Superfamília Shaker de Canais de Potássio/metabolismo
5.
Biophys J ; 106(1): 134-44, 2014 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-24411245

RESUMO

Kv channels detect changes in the membrane potential via their voltage-sensing domains (VSDs) that control the status of the S6 bundle crossing (BC) gate. The movement of the VSDs results in a transfer of the S4 gating charges across the cell membrane but only the last 10-20% of the total gating charge movement is associated with BC gate opening, which involves cooperative transition(s) in the subunits. Substituting the proline residue P475 in the S6 of the Shaker channel by a glycine or alanine causes a considerable shift in the voltage-dependence of the cooperative transition(s) of BC gate opening, effectively isolating the late gating charge component from the other gating charge that originates from earlier VSD movements. Interestingly, both mutations also abolished Shaker's sensitivity to 4-aminopyridine, which is a pharmacological tool to isolate the late gating charge component. The alanine substitution (that would promote a α-helical configuration compared to proline) resulted in the largest separation of both gating charge components; therefore, BC gate flexibility appears to be important for enabling the late cooperative step of channel opening.


Assuntos
4-Aminopiridina/farmacologia , Ativação do Canal Iônico , Bloqueadores dos Canais de Potássio/farmacologia , Superfamília Shaker de Canais de Potássio/metabolismo , Sequência de Aminoácidos , Células HEK293 , Humanos , Dados de Sequência Molecular , Mutação , Estrutura Terciária de Proteína , Superfamília Shaker de Canais de Potássio/antagonistas & inibidores , Superfamília Shaker de Canais de Potássio/química , Superfamília Shaker de Canais de Potássio/genética
6.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 3): m139-40, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23476488

RESUMO

The title compound, [Pd(C26H45S4)Cl]·CH2Cl2, crystallizes with a disordered dichloro-methane solvent mol-ecule [occupancy ratio = 0.67 (4):0.33 (4)]. Two of the tert-butyl groups are also disordered [occupancy ratios = 0.70 (5):0.30 (5) and 0.63 (4):0.37 (4)]. Although the pincer ligand offers the possibility for coordination of two different metal atoms, the present structure shows only the coordination of a single Pd(II) atom in a typical S-C-S tridentate pincer manner. The Pd(II) atom is in a slightly distorted square-planar environment with the two tert-butyl-sulfanyl groups arranged in a trans con-formation and with a chloride ligand trans to the σ-bonded aromatic C atom. The structure exhibits a durene-like ligand frame, forming a dihedral angle of 13.6 (4)° with the metal coordination (Pd/S/S/Cl/C) environment. It is noteworthy that the tert-butyl groups are found in a syn arrangement, this being different to that found previously by Loeb, Shimizu & Wisner [(1998). Organometallics, 17, 2324-2327].

7.
Acta Crystallogr Sect E Struct Rep Online ; 69(Pt 2): o306, 2013 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-23424571

RESUMO

The complete mol-ecule of the title compound, C(19)H(32)S(2), is generated by crystallorgaphic twofold symmetry, with three C atoms lying on the axis. The C(ar)-C-S-C (ar = aromatic) torsion angle is 156.2 (2) °. In the crystal, the mol-ecules are linked by very weak C-H⋯S inter-actions, generating [001] chains.

8.
Eur J Pharmacol ; 663(1-3): 1-8, 2011 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-21539835

RESUMO

Our study on the wild-type and mutants of the voltage-dependent sodium channel in the rat skeletal muscle Na(v) 1.4 was to examine the possible binding site of primaquine PQ by using an experimental approach. We used a standard voltage-clamp in oocytes. Previously, we had demonstrated that PQ blocks the voltage-dependent sodium current in rat myocytes and that this blocking is concentration-dependent and voltage-independent. The direct-site mutagenesis in the P-loop segment W402C, W756C, W1239C, W1531A at the outer tryptophan-rich lip, and D400C, E758C, K1237C, A1529C of the DEKA locus helped us to identify residues playing a key role in aminoquinoline binding. In full agreement with our computed results, where a 1000-fold reduction of inhibition was measured, the tryptophan 756 is crucial for the reversible modulating effects of PQ. The W756C decreased the blocking effect of PQ in voltage-clamp assays. This new binding site may be important to the development of new drugs that modulate sodium inward currents.


Assuntos
Primaquina/metabolismo , Canais de Sódio/química , Canais de Sódio/metabolismo , Triptofano , Animais , Sítios de Ligação , Feminino , Modelos Moleculares , Mutagênese Sítio-Dirigida , Ligação Proteica , Estrutura Terciária de Proteína , Ratos , Canais de Sódio/genética , Especificidade por Substrato
9.
Salud Publica Mex ; 53 Suppl 3: S312-22, 2011.
Artigo em Espanhol | MEDLINE | ID: mdl-22344376

RESUMO

To present the main results of the regional situation diagnosis and intervention plan developed in 2010 as part of the planning activities of the Mesoamerican Health System by the Working Group on Maternal, Reproductive and Neonatal Health. A group of experts and representatives from countries in the region (Central America and nine southern Mexican states) conducted an exhaustive review of available data to construct a situational analysis and a review of effective practices for improving maternal, reproductive and neonatal health. Finally, the group proposed a regional action plan, defining regional goals and specific interventions. The situational diagnosis suggests that, although there has been progress in the last 10 years, maternal and neonatal mortality rates are still unnaceptably high in the region, with a substantial variability across countries. The group proposed as a regional goal the reduction of maternal and neonatal mortality in accordance with the Millenium Development Goals. The regional plan recommends specific maternal and neonatal health interventions emphasizing obstetric and neonatal emergency care, skilled birth attendance and family planning. The plan also includes a five year implementation strategy, along with training and evaluation strategies. The regional plan for maternal, neonatal and reproductive health has the potential to be successful, provided it is effectively implemented.


Assuntos
Promoção da Saúde/organização & administração , Bem-Estar do Lactente , Bem-Estar Materno , Saúde Reprodutiva , Adolescente , Adulto , América Central , Criança , Serviços de Saúde da Criança/organização & administração , Serviços de Saúde da Criança/provisão & distribuição , Países em Desenvolvimento , Serviços de Planejamento Familiar , Feminino , Objetivos , Implementação de Plano de Saúde , Necessidades e Demandas de Serviços de Saúde , Humanos , Mortalidade Infantil/tendências , Recém-Nascido , Cooperação Internacional , Serviços de Saúde Materna/organização & administração , Serviços de Saúde Materna/provisão & distribuição , Mortalidade Materna/tendências , México , Pessoa de Meia-Idade , Gravidez , Regionalização da Saúde , Adulto Jovem
10.
Salud pública Méx ; 53(supl.3): s312-s322, 2011. graf, tab
Artigo em Espanhol | LILACS | ID: lil-625711

RESUMO

Presentar los principales resultados del diagnóstico situacional y plan regional de intervenciones en salud materna, reproductiva y neonatal elaborado como parte de los trabajos del Sistema Mesoamericano de Salud por el grupo de salud materna, reproductiva y neonatal (SMRN) en 2010. Se conformó un grupo de expertos y de representantes de los países de la región (que incluye Centroamérica y nueve estados del sur de México). Se hizo una revisión documental para conformar un diagnóstico situacional, una revisión de prácticas efectivas y se conformó un plan regional de acción. El diagnóstico situacional indica que las tasas de mortalidad materna y neonatal se mantienen inaceptablemente altas en la región. Se propuso como meta regional reducir la mortalidad materna y neonatal de acuerdo a los Objetivos de Desarrollo del Milenio. Se conformó un plan regional que identifica intervenciones específicas en SMRN con énfasis en la atención adecuada a las emergencias obstétricas y neonatales, atención calificada al nacimiento, y en planificación familiar. Se sugiere asimismo un plan de implementación a cinco años y una estrategia de evaluación y de capacitación. El plan regional en SMRN puede tener éxito siempre y cuando los aspectos de implementación sean atendidos debidamente.


To present the main results of the regional situation diagnosis and intervention plan developed in 2010 as part of the planning activities of the Mesoamerican Health System by the Working Group on Maternal, Reproductive and Neonatal Health. A group of experts and representatives from countries in the region (Central America and nine southern Mexican states) conducted an exhaustive review of available data to construct a situational analysis and a review of effective practices for improving maternal, reproductive and neonatal health. Finally, the group proposed a regional action plan, defining regional goals and specific interventions. The situational diagnosis suggests that, although there has been progress in the last 10 years, maternal and neonatal mortality rates are still unnaceptably high in the region, with a substantial variability across countries. The group proposed as a regional goal the reduction of maternal and neonatal mortality in accordance with the Millenium Development Goals. The regional plan recommends specific maternal and neonatal health interventions emphasizing obstetric and neonatal emergency care, skilled birth attendance and family planning. The plan also includes a five year implementation strategy, along with training and evaluation strategies. The regional plan for maternal, neonatal and reproductive health has the potential to be successful, provided it is effectively implemented.


Assuntos
Adolescente , Adulto , Criança , Feminino , Humanos , Recém-Nascido , Pessoa de Meia-Idade , Gravidez , Adulto Jovem , Promoção da Saúde/organização & administração , Bem-Estar do Lactente , Bem-Estar Materno , Saúde Reprodutiva , América Central , Serviços de Saúde da Criança/organização & administração , Serviços de Saúde da Criança/provisão & distribuição , Países em Desenvolvimento , Serviços de Planejamento Familiar , Objetivos , Implementação de Plano de Saúde , Necessidades e Demandas de Serviços de Saúde , Mortalidade Infantil/tendências , Cooperação Internacional , Serviços de Saúde Materna/organização & administração , Serviços de Saúde Materna/provisão & distribuição , Mortalidade Materna/tendências , México , Regionalização da Saúde
11.
Carbohydr Res ; 344(9): 1123-6, 2009 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-19362711

RESUMO

A seven-step total synthesis of Hagen's gland lactones 1 and 2 starting from 1,2-O-isopropylidene-alpha-D-xylofuranose 3 is reported. The success of this short and practical synthesis depends on the use of two key reactions: a stereoselective nucleophilic substitution at the anomeric position of 5 and 6, which allowed the construction of the gamma-lactone ring, and an alkyl substitution reaction on tosylated compound 4, which permitted the carbon chain elongation of the tetrahydrofuran ring appendage at C-6.


Assuntos
Lactonas/síntese química , Vespas/química , Animais , Cinética , Lactonas/química , Monossacarídeos/química , Controle Biológico de Vetores , Estereoisomerismo , Especificidade por Substrato
12.
Acta Crystallogr Sect E Struct Rep Online ; 65(Pt 7): o1456, 2009 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-21582760

RESUMO

In the title compound, C(15)H(20)O(5)S, the tetra-hydro-furan ring shows an envelope conformation. The crystal packing is stabilized by an inter-molecular O-H⋯O hydrogen bond, generating a ribbon structure along the a axis. Two weak inter-molecular C-H⋯O inter-actions are also observed.

13.
Gac. méd. Méx ; 129(1): 57-62, ene.-feb. 1993. tab
Artigo em Espanhol | LILACS | ID: lil-177090

RESUMO

Se estudiaron 100 pacientes con tuberculosis pulmonar en el medio rural y 74 en el medio urbano, con el objetivo de estudiar las principales causas de abandono del tratamiento. La incidencia del abandono global fue del 42 por ciento (73/174): los factores con mayor fuerza de asociación para abandono, independientemente de la asociación con otros factores, fueron el vivir en un medio rural (RM=10.4; p < 0.001), el no tener escolaridad alguna (analfabeta) (RM=4.5; p < 0.001) y el tomar más de una hora en trasladarse a la unidad de atención médica (RM=2.5; p=0.07). No se encontró asociación con las variables socioeconómicas interrogadas, ni con el conocimiento de la enfermedad por el paciente. Identificar los factores que condicionan el abandono del tratamiento contra la tuberculosis es de primordial importancia, sobre todo si se considera que la mayoría de los abandonos ocurren en los primeros días del tramiento, donde estrategias como el tratamiento acortado de menor número de dosis tienen poca influencia. El mejorar el control del tratamiento seguramente contribuirá a lograr el control deseado de esta enfermedad


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Fatores de Risco , Recusa do Paciente ao Tratamento/psicologia , Tuberculose Pulmonar/terapia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...