154 research outputs found
Fototerapia para el tratamiento de la leishmaniasis cutánea
ResumenLa leishmaniasis es una enfermedad endémica en 98 países, con más de 350 millones de personas en riesgo de adquirir la infección y 12 millones de casos. Los antimonios pentavalentes, la anfotericina B y la miltefosina han sido el tratamiento de elección para todas las formas de leishmaniasis. Sin embargo, desventajas como el alto costo, la duración del tratamiento y los efectos tóxicos asociados, promueven la falta de cumplimiento del tratamiento o su abandono y la aparición de cepas resistentes o poco sensibles al medicamento. Estos factores han estimulado la búsqueda de alternativas terapéuticas que sean económicas, sin efectos adversos y con resultados cosméticos favorables. La fototerapia es un procedimiento en el cual un agente fotosensibilizador, al ser activado por luz da lugar a la producción de especies reactivas del oxígeno. Este tratamiento utilizado en varias formas de cáncer, herpes y otras enfermedades e infecciones localizadas, surge como una prometedora estrategia para la leishmaniasis cutánea, con amplias ventajas como bajo costo, fácil manejo y resolución total de la lesión, haciéndola favorable frente a otras alternativas de manejo de la enfermedad.AbstractLeishmaniasis is an endemic disease in 98 countries around the world, with 12 million cases and more than 350 million people at risk of acquiring infection. Available drugs such as pentavalent antimony, amphotericin B and miltefosine, have been the treatment of choice for all clinical forms of leishmaniasis. However, disadvantages such as high cost, duration of treatment and toxicity, promote non-adherence or neglect of treatment and the emergence of resistant or less sensitive to medicine. These problems have stimulated the search of new therapeutic alternatives that are affordable, without adverse effects and favorable cosmetic results. Phototherapy is a procedure in which an agent photosensitizer when activated by light leads to production reactive oxygen species. This therapy used in the treatment of various forms of cancer, herpes and other and localized infectious diseases, is emerging as a promising strategy for the treatment of cutaneous leishmaniasis with large advantages such as low cost, easy handling and total resolution injury, becoming a very promising alternative compared to the traditional treatment approaches
Generalized Wick's theorem for multiquasiparticle overlaps as a limit of Gaudin's theorem
We are able to rederive in a very simple way the standard generalized Wick's
theorem for overlaps of mean field wave functions by using the extension of the
statistical Wick's theorem (Gaudin's theorem) in the appropriate limits.Comment: 28 page
Synthesis, In Silico Studies, Antiprotozoal and Cytotoxic Activities of Quinoline‐Biphenyl Hybrids
This is the pre-peer reviewed version of the following article: Synthesis, In Silico Studies, Antiprotozoal and Cytotoxic Activities of Quinoline‐Biphenyl Hybrids, which has been published in final form at https://doi.org/10.1002/slct.201903835. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsThe synthesis, in silico studies, antiprotozoal and cytotoxic activities of eleven quinoline‐biphenyl hybrids are described herein. The structure of the synthesized products was elucidated by a combination of spectrometric analyses. The synthesized compounds were evaluated against Plasmodium falciparum, and amastigotes forms both Leishmania (V) panamensis and Trypanosoma cruzi. Cytotoxicity was evaluated against human U‐937 macrophages. 8‐phenylquinoline (4 a) showed similar activity than meglumine antimoniate and 4‐(quinolin‐8‐yl)phenol (4 b) exhibited an activity similar to that of benznidazole. 8‐(3,4‐dimethoxyphenyl) quinoline (4 k) showed the best activity against P. falciparum. Although these compounds were toxic for mammalian U‐937 cells, however they may still have potential to be considered as candidates for drug development because of their antiparasite activity. Molecular docking was used to determine the in silico inhibition of some of the designed compounds against PfLDH and cruzipain, two important pharmacological targets involved in antiparasitic diseases. All hybrids were docked to the three‐dimensional structures of PfLDH and T. cruzi cruzipain as enzymes using AutoDock Vina. Notably, the docking results showed that the most active compounds 4‐(quinolin‐8‐yl)phenol (4 b, CE50: 11.33 μg/mL for T. cruzi) and 8‐(3,4‐dimethoxyphenyl) quinoline (4 k, CE50: 8.84 μg/mL for P. falciparum) exhibited the highest scoring pose (−7.5 and −7.7 kcal/mol, respectively). This result shows a good correlation between the predicted scores with the experimental data profile, suggesting that these ligands could act as competitive inhibitors of PfLDH or T. cruzi cruzipain enzymes, respectively. Finally, in silico ADME studies of the quinoline hybrids showed that these novel compounds have suitable drug‐like properties, making them potentially promising agents for antiprotozoal therapy
Application of the Eco-Epidemiological Method in the Study of Leishmaniasis Transmission Foci
The study of transmission foci involves the clinical characterization of disease within a focus using active surveillance of human cases, characterization of the population group that is most frequently infected or at highest risk of becoming infected, diagnosis and treatment of infected people and identification of the conceptions, attitudes, beliefs and practices related to the disease. An entomological survey is necessary to determine the geographical distribution of species and incrimination of vector species, the ecological characteristics of the zone (macro-focus), times of the year and day of highest biting activity and places in homes in which the most frequent contact between the people and the vectors occurs. A survey of peri-domestic and wild mammals in the area is advisable to try to identify potential reservoir hosts. Using this information, it is feasible to design specific and accurate prevention and effective, rational and economic control measures and define the times of the year and locations in which these measures must be applied. In this chapter, a description of the application of the eco-epidemiological method to the study of leishmaniasis transmission foci is provided. A special emphasis is placed on the methodology, multidisciplinary work and analysis of findings
Synthesis and Evaluation of Thiochroman-4-One Derivatives as Potential Leishmanicidal Agents
ABSTARCT: The S-containing heterocyclic compounds benzothiopyrans or thiochromones stand out as having promising biological activities due to their structural relationship with chromones (benzopyrans), which are widely known as privileged scaffolds in medicinal chemistry. In this work, we report the synthesis of 35 thiochromone derivatives and the in vitro antileishmanial and cytotoxic activities. Compounds were tested against intracellular amastigotes of Leishmania panamensis and cytotoxic activity against human monocytes (U-937 ATCC CRL-1593.2). Compounds bearing a vinyl sulfone moiety, 4h, 4i, 4j, 4k, 4l and 4m, displayed the highest antileishmanial activity, with EC50 values lower than 10 μM and an index of selectivity over 100 for compounds 4j and 4l. When the double bond or the sulfone moiety was removed, the activity decreased. Our results show that thiochromones bearing a vinyl sulfone moiety are endowed with high antileishmanial activity and low cytotoxicity
Synthesis, antiprotozoal activity and cytotoxicity in U-937 macrophages of triclosan–hydrazone hybrids
The synthesis and biological activities (cytotoxicity, leishmanicidal, and trypanocidal) of 11 triclosan–hydrazone hybrids are described herein. The structure of the products was elucidated by spectral data (NMR, IR) and mass spectrometric analyses. The synthesized compounds were evaluated against amastigotes forms of L. (V) panamensis, which is the most prevalent Leishmania species in Colombia, and against Trypanosoma cruzi, which is the major pathogenic species to Chagas disease in humans. In addition, the cytotoxic activity of the synthesized compounds was evaluated against human U-937 macrophages. Hydrazone hybrids were obtained as E-synperiplanar and E-antiperiplanar conformers. Nine of them were active against L. (V) panamensis (5a–5d, 5f–5j) and eight of them against T. cruzi (5a, 5c, 5d, 5f–5j), with EC50 values lower than 40 µM. The compounds 5c, 5e, and 5h exhibit the best selectivity index against both L. (V) panamensis and T. cruzi, with values ranging from 5.90 to 16.55, thus showing potential as starting compounds for the eventual development of drugs against these parasites. The presence of hydroxy or methoxy groups in positions 2 and 4 of the aromatic ring of the benzylidene moiety increases both activity and cytotoxicity. There is no clear relationship between the antiprotozoal activity and the methylation pattern of the hydroxy groups, since in some cases methylation decreases the activity (5d vs. 5g) while in other cases the activity is increased (5c vs. 5f and 5i vs. 5j
Leishmanicidal and cytotoxic activity of extracts and saponins from Ilex laurina (Aquifoliaceae)
Purpose: To evaluate the leishmanicidal and cytotoxic activity of alcohol and non-alcohol extracts and saponins from Ilex laurina.Methods: Extracts were obtained by percolation with solvents of different polarities: hexane, dichloromethane, ethyl acetate and ethanol. The ethyl acetate extract was subjected to silica gel column chromatography eluting with a step gradient of dichloromethane-methanol. All products were evaluated in vitro for leishmanicidal activity against amastigotes of leishmania panamensis and cytotoxicity on U-937 cells.Results: Two saponins were isolated from the ethyl acetate extract. The ethyl acetate extract showed high leishmanicidal activity against intracellular amastigotes of L. panamensis (EC50, 7.5 ± 1.5 μg/mL) and low activity against axenic amastigotes (EC50, 52.8 ±1.6 μg/mL); this extract showed also high cytotoxicity (LC50, 57.7 ± 12.1 μg/mL). Saponin 2 exhibited high activity against intracellular amastigotes (EC50, 5.9 ± 0.5 μg/mL) but also showed high cytotoxicity on U-937 cells (EC50, 25.7 ± 6.1 μg/mL). This compound showed similar leishmanicidal activity and cytotoxicity to meglumine antimoniate and amphotericin B, respectively, drugs currently used for the treatment of leishmaniasis.Conclusions: Based on these results, Ilex laurina is a potential source of compounds that can lead to the development of new therapeutic alternatives against leishmaniasis.Keywords: Leishmaniasis, Antiprotozoal, Saponin, Ilex laurina, Aquifoliacea
Improved corrosion resistance of commercially pure magnesium after its modification by plasma electrolytic oxidation with organic additives
The optimal mechanical properties render magnesium widely used in industrial and biomedical applications. However, magnesium is highly reactive and unstable in aqueous solutions, which can be modulated to increase stability of reactive metals that include the use of alloys or by altering the surface with coatings. Plasma electrolytic oxidation is an efficient and tuneable method to apply a surface coating. By varying the plasma electrolytic oxidation parameters voltage, current density, time and (additives in the) electrolytic solution, the morphology, composition and surface energy of surface coatings are set. In the present study, we evaluated the influence on surface coatings of two solute additives, i.e. hexamethylenetetramine and mannitol, to base solutes silicate and potassium hydroxide. Results from in vitro studies in NaCl demonstrated an improvement in the corrosion resistance. In addition, coatings were obtained by a two-step anodization procedure, firstly anodizing in an electrolyte solution containing sodium fluoride and secondly in an electrolyte solution with hexamethylenetetramine and mannitol, respectively. Results showed that the first layer acts as a protective layer which improves the corrosion resistance in comparison with the samples with a single anodizing step. In conclusion, these coatings are promising candidates to be used in biomedical applications in particular because the components are non-toxic for the body and the rate of degradation of the surface coating is lower than that of pure magnesium
Synthesis, Leishmanicidal and Cytotoxic Activity of Triclosan-Chalcone, Triclosan-Chromone and Triclosan-Coumarin Hybrids
Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V) panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7–9 and 17, were active against Leishmania parasites (EC50 = 9.4; 10.2; 13.5 and 27.5 µg/mL, respectively) and showed no toxicity toward mammalian cells (>200 µg/mL). They are potential candidates for antileishmanial drug development. Compounds 25–27, were active and cytotoxic. Further studies using other cell types are needed in order to discriminate whether the toxicity shown by these compounds is against tumor or non-tumor cells. The results indicate that compounds containing small alkyl chains show better selectivity indices. Moreover, Michael acceptor moieties may modify both the leishmanicidal activity and cytotoxicity. Further studies are required to evaluate if the in vitro activity against Leishmania panamensis demonstrated here is also observed in vivo.The authors thank COLCIENCIAS (contract No. 0333-2013, code: 111556933423) and the Universidad de Antioquia (Estrategia de Sostenibilidad 2013–2014 and CIDEPRO) for financial support
Vigilancia de la fauna flebotomínea e infección de Didelphis marsupialis (Didelphimorphia: Didelphidae) en un área de alta endemia de leishmaniasis visceral en Colombia
Introduction: The study of the interaction between the parasite, the vector and the mammalian hosts, including man, allows to understand the behavior of the leishmaniases.Objective: To determine the presence of Lutzomyia species and to detect the Leishmania infection in Didelphis marsupialis in an endemic area for visceral leishmaniasis.Materials and methods: Phlebotomine fauna and individuals of D. marsupialis were collected with CDC and Tomahawk™ traps, respectively. The species of Lutzomyia were identified using the Young and Duncan key (1994). Ear and tail biopsies and blood samples from D. marsupialis were taken to identify the Leishmania species by amplifying a fragment of the gene associated with the 70 kD heat shock protein.Results: Seven Lutzomyia species were identified: Lu. evansi, Lu. gomezi, Lu. panamensis, Lu. dubitans, Lu. cayennensis cayennensis, Lu. rangeliana and Lu. trinidadensis. The first three species have epidemiological importance in Colombia because of their implications in the transmission of the Leishmania parasite. Sixty-five tissue samples from 19 D. marsupialis individuals were negative for Leishmania spp. Conclusions: The presence of the Lutzomyia species that have been identified as vectors for Leishmania inside and around houses in the village of El Bledo, in El Carmen de Bolívar represents a risk of infection. Furthermore, the presence of Lu. panamensis is reported for first time in El Carmen de Bolívar in Colombia. Although the lack of detection of Leishmania spp. in D. marsupialis samples may suggest that D. marsupialis does not play an important role in the transmission cycle of Leishmania in this region, it is necessary to carry out further longitudinal studies to confirm this hypothesisIntroducción. El estudio de la interacción entre el parásito, el vector y los huéspedes mamíferos, incluido el hombre, permite entender el comportamiento de la leishmaniasis.Objetivo. Determinar la presencia de especies del género Lutzomyia y detectar la infección por Leishmania spp. en Didelphis marsupialis en un área endémica de leishmaniasis visceral.Materiales y métodos. Se recolectaron flebotomíneos y D. marsupialis con trampas CDC y Tomahawk™, respectivamente. Las especies de Lutzomyia se identificaron usando la clave de Young y Duncan, 1994. Se tomaron biopsias de oreja, cola y muestras de sangre de D. marsupialis para diagnosticar Leishmania spp. mediante la amplificación de un fragmento del gen de la proteína de choque térmico de 70 kD. Resultados. Se identificaron siete especies de Lutzomyia: Lu. evansi, Lu. gomezi, Lu. panamensis, Lu. dubitans, Lu. cayennensis cayennensis, Lu. rangeliana y Lu. trinidadensis. Las tres primeras especies son reconocidas como vectores en el país por estar implicadas en la transmisión de Leishmania spp. En total, 65 muestras de tejidos de oreja, cola y de sangre provenientes de 19 D. marsupialis fueron negativas para Leishmania spp. en la PCR-HSP70.Conclusiones. La presencia de flebotomíneos con importancia epidemiológica en la zona evaluada representa un riesgo de transmisión. Asimismo, Lu. panamensis es reportada por primera vez en El Bledo (Carmen de Bolívar). La ausencia de Leishmania spp. en D. marsupialis podría sugerir que esta especie no tiene un papel importante en el ciclo de transmisión de Leishmania en la vereda El Bledo, por lo que es necesario profundizar en estudios longitudinales para corroborar esta hipótesis
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