Tuning the Emission Properties of 2,1,3-Benzothiadiazoles via Regioselective Substitution.

The 2,1,3-benzothiadiazole (BTD) unit is a prominent building block commonly used in various research areas such as optoelectronics and bioimaging. Despite its great versatility, the development of strategies to elaborate BTD has been largely neglected, including exploring its reactivity and understanding how regioselective functionalization can be used to tune the fluorescence emission. Previous focus has primarily been on C4- or C4,C7-substitutions. Here, a series of unsymmetrical mono - and disubstituted BTDs was synthesized and characterized for their photophysical properties. The reaction scope includes all six possible substituent patterns on the BTD benzoid ring (C4-, C5-, C4,C5-, C4,C6-, C4,C7- and C5,C6-substitution), which comprise arrangements that previously been synthetically challenging to access. By introducing a methoxy and/or a phenyl group we demonstrate that the emissive behavior of BTD derivatives strongly depends on the position of the substituent (s). We show that regioselective substitution on BTD can engender long-lived fluorescence and circumvent strong fluorescence quenching in polar protic solvents, which is a limitation of many previously described BTD derivatives.

Derivatization of 2,1,3-Benzothiadiazole via Regioselective C-H Functionalization and Aryne Reactivity.

Despite growing interest in 2,1,3-benzothiadiazole (BTD) as an integral component of many functional molecules, methods for the functionalization of its benzenoid ring have remained limited, and many even simply decorated BTDs have required de novo synthesis. We show that regioselective Ir-catalyzed C-H borylation allows access to versatile 5-boryl or 4,6-diboryl BTD building blocks, which undergo functionalization at the C4, C5, C6, and C7 positions. The optimization and regioselectivity of C-H borylation are discussed. A broad reaction scope is presented, encompassing ipso substitution at the C-B bond, the first examples of ortho-directed C-H functionalization of BTD, ring closing reactions to generate fused ring systems, as well as the generation and capture reactions of novel BTD-based heteroarynes. The regioselectivity of the latter is discussed with reference to the Aryne Distortion Model.

[Reactivity and evolution of 4022 patch tests in Chilean patients with contact dermatitis]. / Reactividad y evolución de 4.022 tests de parche en dermatitis de contacto realizadas entre 1995 y 2011 en Santiago de Chile.

BACKGROUND: Allergic Contact Dermatitis is a classic delayed hypersensitivity reaction. AIM: To study the reactivity and evolution in Chilean patients by gender, using the standard European patch test. MATERIALS AND METHODS: The results of the European standard patch test applied to 4,022 patients aged 1 to 93 years (64% female) with Allergic Contact Dermatitis, diagnosed between January 1995 and August 2011, were retrospectively analyzed. RESULTS: From a total of 4,022 patients, 2,439 (60.6%) had a positive reaction. Among reactive patients, 1,854 (76.04%) were female and 584 (23.96%) male. The most common positive allergens were nickel (35.3%), cobalt (15.1%), fragrance mix (14%), chromium (8.7%) and balsam of Peru (8.5%). In females, nickel was the most common reactive antigen (34.28%), and in males, fragrance mix (15.7%). During the period 2003-2011, an increased reactivity to nickel (26.6%) and a decreased reactivity to p-phenylenediamine (29.6%) and fragrance (42.8%), was observed. CONCLUSIONS: Fragrance mix is the most common reactive allergen in males and the third for females. Nickel is the leading allergen in the female group and the second of importance for males, making it the most significant allergen for the Chilean population. We also observed that the reactivity of some allergens evolves and varies over time.

Access to long-lived room temperature phosphorescence through auration of 2,1,3-benzothiadiazole.

A series of 2,1,3-benzothiadiazole-Au(I)-L complexes have been synthesised, structurally characterised and investigated for their photophysical properties. These are the first organometallic Au(I) complexes containing a C-Au bond on the highly electron-deficient benzothiadiazole unit. The complexes exhibit solution-phase phosphorescence at room temperature, assigned to the intrinsic triplet state of the benzothiadiazole unit that is efficently populated through its attachment to gold. Comparison with routinely reported Au(I) complexes, which include intervening alkenyl linkers, suggests that previous assignments of their phosphorescence as 1π → π*(CCR) might be incomplete. Our observations affirm that, in addition to the heavy atom effect, breaking symmetry in the involved aryl motif may be of importance in controlling the luminescence properties.

[Tinea nigra: a allochthonous case report in Chile]. / Tiña negra (tinea nigra): comunicación de un caso alóctono en Chile.

Tinea nigra is a superficial mycosis caused by Hortaea werneckii. It is an infrequent asymptomatic infection that affects mainly human palms and soles, and it is mostly seen in tropical countries. It has not been reported in Chile yet. The clinical presentation is generally a single macule, not symptomatic, of brown color in palms and soles. We report a case of a Chilean woman that developed brown macules on both soles after travel to the United States and Central America. The diagnosis of Tinea nigra was confirmed by direct microscopic examination and mycological culture. She had a good response to treatment with oral itraconazol.

[First autochthonous case report of tinea nigra in Chile]. / Primer reporte de caso autóctono de tinea nigra en Chile.

Tinea nigra is an infrequent superficial mycosis caused by the dematiaceous fungus Hortaea werneckii. It usually occurs in tropical coastal areas, with very few reports in South American countries with temperate climates, generally corresponding to infections imported by travelers. We present the case of a Chilean adult patient, with no previous history of recent trips, with clinical and microbiological background consistent with palmar tinea nigra, treated with oral itraconazole and topical sertaconazole with a favorable response. This article is the first case reported in Chile, of autochthonous origin.

La tinea nigra es una infrecuente micosis superficial causada por el hongo dematiáceo Hortaea werneckii. Se presenta habitualmente en zonas costeras tropicales, siendo muy escasos los reportes en países sudamericanos con climas más templados. Habitualmente corresponde a infecciones importadas por viajeros. Se presenta el caso de una paciente adulta chilena, sin historia previa de viajes recientes, cursando con cuadro clínico y microbiológico compatible con tinea nigra palmar, tratado con itraconazol oral y sertaconazol tópico con respuesta favorable. Esta paciente corresponde al primer caso reportado en Chile de origen autóctono.

[Venom of Latrodectus mactans from Chile (Araneae, Theridiidae): effect on smooth muscle]. / Veneno de Latrodectus mactans de Chile (Araneae, Theridiidae): su efecto sobre músculo liso.

The venoms of Latrodectus sp. have been reported to induce contraction probably mediated by adrenergic and cholinergic transmitters. We have demonstrated that the venom of Chilean Latrodectus mactans contains neurotoxins that induce a contraction partially independent of transmitters release. Transmembrane mobility of Na+ and Ca2+ ions and more specifically, the increase of cytoplasmic calcium concentration are responsible for tonic contraction in smooth muscle. Calcium may enter the cell by several ways, such as the voltage-dependent Ca2+ L-type channels and the Na+/Ca2+ exchanger. This study aimed to examine the participation of this exchanger in the tonic contraction of smooth muscle in vas deferent of rat induced by the venom of the Chilean spider L. mactans. Blockers of Na+ channels (amiloride) and Ca2+ L-type channels (nifedipine), and a stimulator of the exchanger (modified Tyrode, Na+ 80 mM) were used. Simultaneously, variations of the cytoplasmic concentration of Ca2+ were registered by microfluorimetry (Fura-2 indicator) in the presence of nifedipine. In presence of amiloride, dose-dependent inhibition of venom-induced contraction was observed, suggesting the participation of voltage-dependent Ca2+ L-type channels. The contraction was only partially inhibited by nifedipine and the Ca2+ cytoplasmic concentration increased, as assessed by the microfluorimetric registration. Finally, the venom-induced contraction increased in the presence of modified Tyrode, probably due to the action of the Na+/Ca2+ exchanger. Taken together, our results support the idea that the Na+/Ca2+ exchanger is active and may be, at least in part, responsible for the contraction induced by the venom of Chilean L. mactans.

Reactividad y evolución de 4.022 tests de parche en dermatitis de contacto realizadas entre 1995 y 2011 en Santiago de Chile / Reactivity and evolution of 4022 patch tests in Chilean patients with contact dermatitis

Background: Allergic Contact Dermatitis is a classic delayed hypersensitivity reaction. Aim: To study the reactivity and evolution in Chilean patients by gender, using the standard European patch test. Materials and Methods: The results of the European standard patch test applied to 4,022 patients aged 1 to 93 years (64% female) with Allergic Contact Dermatitis, diagnosed between January 1995 and August 2011, were retrospectively analyzed. Results: From a total of 4,022 patients, 2,439 (60.6%) had a positive reaction. Among reactive patients, 1,854 (76.04%) were female and 584 (23.96%) male. The most common positive allergens were nickel (35.3%), cobalt (15.1%), fragrance mix (14%), chromium (8.7%) and balsam of Peru (8.5%). In females, nickel was the most common reactive antigen (34.28%), and in males, fragrance mix (15.7%). During the period 2003-2011, an increased reactivity to nickel (26.6%) and a decreased reactivity to p-phenylenediamine (29.6%) and fragrance (42.8%), was observed. Conclusions: Fragrance mix is the most common reactive allergen in males and the third for females. Nickel is the leading allergen in the female group and the second of importance for males, making it the most significant allergen for the Chilean population. We also observed that the reactivity of some allergens evolves and varies over time.

Tiña negra (tinea nigra): comunicación de un caso alóctono en Chile / Tinea Nigra: a allochthonous case report in Chile

Tinea nigra is a superficial mycosis caused by Hortaea werneckii. It is an infrequent asymptomatic infection that affects mainly human palms and soles, and it is mostly seen in tropical countries. It has not been reported in Chile yet. The clinical presentation is generally a single macule, not symptomatic, of brown color in palms and soles. We report a case of a Chilean woman that developed brown macules on both soles after travel to the United States and Central America. The diagnosis of Tinea nigra was confirmed by direct microscopic examination and mycological culture. She had a good response to treatment with oral itraconazol.

La tiña negra (tinea nigra) es una micosis cutánea causada por Hortaea werneckii. Es poco frecuente, limitada a países tropicales o subtropicales. Hasta la presente publicación, esta micosis no había sido comunicada en Chile. La presentación clínica es generalmente una mácula única, asintomática, color café en palmas y plantas. Se presenta el caso de una mujer chilena, que después de varios viajes a E.U.A y Centroamérica, presentó manchas color café en ambas plantas. Se confirmó el diagnóstico de tiña negra con un examen microscópico directo y cultivo micológico. La paciente presentó una buena respuesta clínica luego del tratamiento con itraconazol por vía oral.

Estandarización de una técnica para la detección de salmonella spp. util para manipuladores de alimentos mediante técnica de amplificación molecular / Standardization of a technique for the detection of salmonella spp. useful for food handlers by molecular amplification technique

El problema de las toxoinfecciones alimentarias es un problema de salud a nivel mundial, entre las que se encuentran las producidas por Salmonella spp.; la prevalencia de sus especies ha cambiado en los últimos años, además del bajo nivel de sensibilidad de los métodos tradicionales de aislamiento como es el caso del coprocultivo. Debido a esto el objetivo de este trabajo fue estandarizar una metodología molecular (PCR) para este patógeno a partir de muestras fecales; los resultados mostraron gran sensibilidad y especificidad, haciendo factible su utilización en manipuladores de alimentos.

Brettanomyces, un contaminante en nuestras viñas / Brettanomyces, a contaminant in our vineyards

Uno de los avances de la enología moderna es el reconocimiento de la importancia de la levadura como un agente imprescindible para la adecuada obtención de vino. El proceso de fermentación es dinámico y existe un recambio de especies de levaduras desde el principio al final de la fermentación. Sin embargo, una de ellas, Brettanomyces, puede contaminar los caldos, alterando las cualidades aromáticas y de sabor del vino, provocando en algunos casos la pérdida del producto vinificado.Además de una importante pérdida económica, cifras extraoficiales indican que hasta un 5 por ciento de la producción nacional se pierde cada año producto de este hongo; el monto en pérdidas, sólo en vino embotellado, podría llegar a los US$30.000.000. La reacción en cadena de la polimerasa (PCR, Polimerase chain reaction) puede ser utilizada para detectar diminutas cantidades de ADN de un microorganismo. Esta técnica permite detectar este contaminante en no más de 24 horas, presenta una alta sensibilidad, necesitándose una cantidad ínfima de microorganismos en la muestra (1-100) levaduras por mL. El diagnóstico oportuno de la contaminación de los vinos por esta levadura permitiría adoptar medidas que controlen la proliferación de este contaminante, reduciendo las pérdidas del producto.

Veneno de Latrodectus mactans de Chile (Araneae, Theridiidae): su efecto sobre músculo liso / Venom of Latrodectus mactans from Chile (Araneae, Theridiidae): effect on smooth muscle

The venoms of Latrodectus sp. have been reported to induce contraction probably mediated by adrenergic and cholinergic transmitters. We have demonstrated that the venom of Chilean Latrodectus mactans contains neurotoxins that induce a contraction partially independent of transmitters release. Transmembrane mobility of Na+ and Ca2+ ions and more specifically, the increase of cytoplasmic calcium concentration are responsible for tonic contraction in smooth muscle. Calcium may enter the cell by several ways, such as the voltage-dependent Ca2+ L-type channels and the Na+/Ca2+ exchanger. This study aimed to examine the participation of this exchanger in the tonic contraction of smooth muscle in vas deferent of rat induced by the venom of the Chilean spider L. mactans. Blockers of Na+ channels (amiloride) and Ca2+ L-type channels (nifedipine), and a stimulator of the exchanger (modified Tyrode, Na+ 80 mM) were used. Simultaneously, variations of the cytoplasmic concentration of Ca2+ were registered by microfluorimetry (Fura-2 indicator) in the presence of nifedipine. In presence of amiloride, dose-dependent inhibition of venom-induced contraction was observed, suggesting the participation of voltage-dependent Ca2+ L-type channels. The contraction was only partially inhibited by nifedipine and the Ca2+ cytoplasmic concentration increased, as assessed by the microfluorimetric registration. Finally, the venom-induced contraction increased in the presence of modified Tyrode, probably due to the action of the Na+/Ca2+ exchanger. Taken together, our results support the idea that the Na+/Ca2+ exchanger is active and may be, at least in part, responsible for the contraction induced by the venom of Chilean L. mactans.