Supramolecular Stability of Benzene-1,3,5-tricarboxamide Supramolecular Polymers in Biological Media: Beyond the Stability-Responsiveness Trade-off.

Supramolecular assemblies have been gaining attention in recent years in the field of drug delivery because of their unique formulation possibilities and adaptive behavior. Their non-covalent nature allows for their self-assembly formulation and responsiveness to stimuli, an appealing feature to trigger a therapeutic action with spatiotemporal control. However, facing in vivo conditions is very challenging for non-covalent structures. Dilution and proteins in blood can have a direct impact on self-assembly, destabilizing the supramolecules and leading to a premature and uncontrolled cargo release. To rationalize this behavior, we designed three monomers exhibiting distinct hydrophobic cores that self-assemble into photo-responsive fibers. We estimated their stability-responsiveness trade-off in vitro, finding two well-separated regimes. These are low-robustness regime, in which the system equilibrates quickly and responds readily to stimuli, and high-robustness regime, in which the system equilibrates slowly and is quite insensitive to stimuli. We probed the performance of both regimes in a complex environment using Förster resonance energy transfer (FRET). Interestingly, the stability-responsiveness trade-off defines perfectly the extent of disassembly caused by dilution but not the one caused by protein interaction. This identifies a disconnection between intrinsic supramolecular robustness and supramolecular stability in the biological environment, strongly influenced by the disassembly pathway upon protein interaction. These findings shed light on the key features to address for supramolecular stability in the biological environment.

Ultrabright Föster Resonance Energy Transfer Nanovesicles: The Role of Dye Diffusion.

The development of contrast agents based on fluorescent nanoparticles with high brightness and stability is a key factor to improve the resolution and signal-to-noise ratio of current fluorescence imaging techniques. However, the design of bright fluorescent nanoparticles remains challenging due to fluorescence self-quenching at high concentrations. Developing bright nanoparticles showing FRET emission adds several advantages to the system, including an amplified Stokes shift, the possibility of ratiometric measurements, and of verifying the nanoparticle stability. Herein, we have developed Förster resonance energy transfer (FRET)-based nanovesicles at different dye loadings and investigated them through complementary experimental techniques, including conventional fluorescence spectroscopy and super-resolution microscopy supported by molecular dynamics calculations. We show that the optical properties can be modulated by dye loading at the nanoscopic level due to the dye's molecular diffusion in fluid-like membranes. This work shows the first proof of a FRET pair dye's dynamism in liquid-like membranes, resulting in optimized nanoprobes that are 120-fold brighter than QDot 605 and exhibit >80% FRET efficiency with vesicle-to-vesicle variations that are mostly below 10%.

NMR Metabolic Profiling of Sargassum Species Under Different Stabilization/Extraction Processes.

The genus Sargassum is well represented by benthic and pelagic species, some of which form massive aggregates that can travel long distances due to the force of the ocean currents. Although they constitute an essential habitat for fish and invertebrate species, large accumulations of Sargassum in coastal areas generate several economic, environmental, and health impacts. It is important to recognize the species forming these aggregates, and identify the metabolites they produce, allowing for its exploitation, and therefore, better management practices. NMR metabolic profiling is a technique that can discriminate samples while detecting their unique or differential chemical features, and has been successfully used in the study and classification of several algal species. The present investigation studied the metabolic profiling of Sargassum species found on strandings at Puerto Morelos (Quintana Roo) east coast of the Mexican Caribbean. PCA of the 1 H-NMR profiles corresponding to S. natans, S. natans (morphotype VIII), S. fluitans, and a benthic Sargassum buxifolium allowed the discrimination of samples amongst them. Furthermore, discrimination between the two forms of S. natans was also possible. The PCA loading plot revealed that glutamine and glutamate have the highest influence in the clustering of the benthic Sargassum, while a high abundance of lactate, Myo-inositol, and trimethylamine is a unique feature from the S. natans morphotype VIII. Additional PLS-DA models showed that a heat-drying process improved the extraction of metabolites. Maceration and microwave-assisted extraction with water-ethanol led to similar profiles and thus any of them could be used in future investigations.

An Azobenzene-Based Single-Component Supramolecular Polymer Responsive to Multiple Stimuli in Water.

One of the most appealing features of supramolecular assemblies is their ability to respond to external stimuli due to their noncovalent nature. This provides the opportunity to gain control over their size, morphology, and chemical properties and is key toward some of their applications. However, the design of supramolecular systems able to respond to multiple stimuli in a controlled fashion is still challenging. Here we report the synthesis and characterization of a novel discotic molecule, which self-assembles in water into a single-component supramolecular polymer that responds to multiple independent stimuli. The building block of such an assembly is a C3-symmetric monomer, consisting of a benzene-1,3,5-tricarboxamide core conjugated to a series of natural and non-natural functional amino acids. This design allows the use of rapid and efficient solid-phase synthesis methods and the modular implementation of different functionalities. The discotic monomer incorporates a hydrophobic azobenzene moiety, an octaethylene glycol chain, and a C-terminal lysine. Each of these blocks was chosen for two reasons: to drive the self-assembly in water by a combination of H-bonding and hydrophobicity and to impart specific responsiveness. With a combination of microscopy and spectroscopy techniques, we demonstrate self-assembly in water and responsiveness to temperature, light, pH, and ionic strength. This work shows the potential to integrate independent mechanisms for controlling self-assembly in a single-component supramolecular polymer by the rational monomer design and paves the way toward the use of multiresponsive systems in water.

PAINT-ing Fluorenylmethoxycarbonyl (Fmoc)-Diphenylalanine Hydrogels.

Self-assembly of fluorenylmethoxycarbonyl-protected diphenylalanine (FmocFF) in water is widely known to produce hydrogels. Typically, confocal microscopy is used to visualize such hydrogels under wet conditions, that is, without freezing or drying. However, key aspects of hydrogels like fiber diameter, network morphology and mesh size are sub-diffraction limited features and cannot be visualized effectively using this approach. In this work, we show that it is possible to image FmocFF hydrogels by Points Accumulation for Imaging in Nanoscale Topography (PAINT) in native conditions and without direct gel labelling. We demonstrate that the fiber network can be visualized with improved resolution (≈50 nm) both in 2D and 3D. Quantitative information is extracted such as mesh size and fiber diameter. This method can complement the existing characterization tools for hydrogels and provide useful information supporting the design of new materials.

Micellar Stability in Biological Media Dictates Internalization in Living Cells.

The dynamic nature of polymeric assemblies makes their stability in biological media a crucial parameter for their potential use as drug delivery systems in vivo. Therefore, it is essential to study and understand the behavior of self-assembled nanocarriers under conditions that will be encountered in vivo such as extreme dilutions and interactions with blood proteins and cells. Herein, using a combination of fluorescence spectroscopy and microscopy, we studied four amphiphilic PEG-dendron hybrids and their self-assembled micelles in order to determine their structure-stability relations. The high molecular precision of the dendritic block enabled us to systematically tune the hydrophobicity and stability of the assembled micelles. Using micelles that change their fluorescent properties upon disassembly, we observed that serum proteins bind to and interact with the polymeric amphiphiles in both their assembled and monomeric states. These interactions strongly affected the stability and enzymatic degradation of the micelles. Finally, using spectrally resolved confocal imaging, we determined the relations between the stability of the polymeric assemblies in biological media and their cell entry. Our results highlight the important interplay between molecular structure, micellar stability, and cell internalization pathways, pinpointing the high sensitivity of stability-activity relations to minor structural changes and the crucial role that these relations play in designing effective polymeric nanostructures for biomedical applications.

Anti-giardia activity and acute toxicity of a methanol extract of Senna racemosa bark.

ETHNOPHARMACOLOGICAL RELEVANCE: Senna racemosa (Mill.) H.S. Irwin & Barneby (syn. Cassia racemosa Mill.) is a plant used in traditional Mayamedicinal practices to treat diarrhea. A methanol extract of S. racemosa bark has been shown to have in vitro activity against Giardia intestinalis. No studies of its efficacy and toxicity in in vivo models have been done. The present study objective was to analyze the activity of this methanol extract of S. racemosa bark against Giardia intestinalis trophozoites in experimentally infected mice, and evaluate its toxicological effects in rats. MATERIAL AND METHODS: S. racemosa was collected in Merida, Yucatan, Mexico (21°58'N, 89°36'W) in June 2005. The bark methanol extract was obtained and high performance liquid chromatography (HPLC-DAD) was used to generate a constituent profile. In vivo anti-giardia activity was assayed with an experimental model of G. intestinalis infection in neonatal CD-1 mice. Nine doses ranging from 0.25-15mg extract/kg body weight were tested to determine the dose required to kill 50% of the trophozoites (ED50). An acute toxicity assay was run in which one of four single doses (200, 1000, 2000 and3000mg/kg body weight) was orally administered to adult Wistar rats. Animal weight, death rates, toxic effects and behavioral parameters were observed over a 14-d period. They were then euthanized and a necropsy performed. RESULTS: The S. racemosa bark extract inhibited growth of G. intestinalis (ED50=1.14mg/Kg) in neonatal CD-1 mice. No toxic or lethal effects were observed even at the highest dosage (3000mg/Kg), and neither were signs of toxicity observed in internal organs. The active compounds chrysophanol and physcion were present in the extract at a 1.76 ratio. CONCLUSIONS: The results strongly support traditional use of S. racemosa bark for treatment of diarrhea caused by Giardia intestinalis infection.

Antiproliferative and Antiestrogenic Activities of Bonediol an Alkyl Catechol from Bonellia macrocarpa.

The purpose of this study was to investigate antiproliferative activity of bonediol, an alkyl catechol isolated from the Mayan medicinal plant Bonellia macrocarpa. Bonediol was assessed for growth inhibition of androgen-sensitive (LNCaP), androgen-insensitive (PC-3), and metastatic androgen-insensitive (PC-3M) human prostate tumor cells; toxicity on normal cell line (HEK 293) was also evaluated. Hedgehog pathway was evaluated and competitive 3H-estradiol ligand binding assay was performed. Additionally, antioxidant activity on Nrf2-ARE pathway was evaluated. Bonediol induced a growth inhibition on prostate cancer cell lines (IC50 from 8.5 to 20.6 µM). Interestingly, bonediol binds to both estrogen receptors (ERα (2.5 µM) and ERß (2.1 µM)) and displaces the native ligand E2 (17ß-estradiol). No significant activity was found in the Hedgehog pathway. Additionally, activity of bonediol on Nrf2-ARE pathway suggested that bonediol could induce oxidative stress and activation of detoxification enzymes at 1 µM (3.8-fold). We propose that the compound bonediol may serve as a potential chemopreventive treatment with therapeutic potential against prostate cancer.

Isolation and Identification of Cytotoxic Compounds from Aeschynomene fascicularis, a Mayan Medicinal Plant.

The plant Aeschynomene fascicularis (Fabaceae) has been used in Mayan traditional medicine in the Yucatan peninsula. However, the compounds present in the plant responsible for its curative properties have not yet been investigated. Aeschynomene fascicularis root bark was extracted with 100% methanol to obtain a crude extract. The methanol extract was partitioned successively with solvents with increasing polarity to obtain the corresponding hexane (Hx), dichloromethane (DCM) and ethyl acetate fractions (EtOAc), as well as a residual water-alcoholic fraction. These fractions were tested for their cytotoxic activities using an MTT assay against Hep-2 cancer cell lines. The Hx fraction led to the isolation of spinochalcone C (1), spinochalcone A (2), isocordoin (3) and secundiflorol G (4). Their structures were identified based on spectroscopic evidence and chemical properties. All compounds were subjected to cytotoxicity and antiproliferative assays against a panel of seven cell lines, including one normal-type cell line. Spinochalcone A (2) exhibited cytotoxic activity against DU-145 cell line and antiproliferative activity against the KB cell line. Secundiflorol G (4) showed strong cytotoxic activity towards KB and Hep-2 cell lines. In addition, isocordoin (3) showed moderate activity on KB, Hep-2 and DU-145 cell lines. The active Compounds 2, 3 and 4 are potential therapeutic entities against cancer.

Cytotoxic and antiproliferative constituents from Dictyota ciliolata, Padina sanctae-crucis and Turbinaria tricostata.

CONTEXT: The hexane extracts of Dictyota ciliolata Sonder ex Kützing (Dictyotaceae), Padina sanctae-crucis Børgesen (Dictyotaceae), and Turbinaria tricostata E.S. Barton (Sargassaceae) were found to exhibit cytotoxic and antiproliferative activities in vitro. Bioactive compounds responsible for these activities have not been studied in detail for these species and phytochemical studies are very limited. OBJECTIVE: Isolate, evaluate, and elucidate the bioactive constituents of D. ciliolata, P. sanctae-crucis, and T. tricostata. MATERIALS AND METHODS: Bioassay-guided cytotoxicity fractionations using the Hep-2 cell line of the hexane extracts from these brown algae were analyzed using various chromatographic techniques. Cytotoxic and antiproliferative activities of all isolated compounds were also evaluated on a panel of cell lines (KB, Hep-2, MCF-7, and SiHa). Furthermore, their selectivity index, the ratio of cytotoxicity on normal cells to cancer cells, was evaluated using the HEK-293 cell line. RESULTS: Four compounds were isolated from studied species: two sterol, fucosterol (1) and 24ξ-hydroperoxy-24-vinylcholesterol (2); and two diterpenes, pachydictyol A (3) and dictyol B acetate (4). The major bioactive components of the hexane extracts of T. tricostata and P. sanctae-crucis were compounds 1 and 2 (with CC50 varying around 3.1-25.6 µg/mL) on cell lines tested. Whereas compounds 1, 3, and 4 showed cytotoxic activity against cancer cell lines (CC50 varying between 14.8 and 41.2 µg/mL) and were major bioactive constituents of hexane extract of D. ciliolata. Compounds 1 and 4 showed antiproliferative activity on MCF-7 (IC50 = 43.3 µg/mL for compound 1 and 38.3 µg/mL for compound 2) and SiHa (IC50 = 43.3 µg/mL for compound 1 and 38.3 µg/mL for compound 2) cell lines. CONCLUSION: This study is the first investigation on the bioactive components of D. ciliolata, P. sanctae-crucis, and T. tricostata. Although compounds 1-3 were described previously, the pharmacological activity of compound 4 is presented here for the first time.

Carga del cuidado y calidad de vida en cuidadores familiares de personas con enfermedad respiratoria crónica / Burden of care and quality of life in family caregivers of people with chronic respiratory disease

Objetivo: Establecer la relación entre la carga del cuidado y la calidad de vida en cuidadores familiares de personas con enfermedades respiratorias crónicas Método: Estudio descriptivo, de correlación, abordaje cuantitativo y corte transversal. Participaron 55 cuidadores familiares que asisten a una institución de tercer nivel de atención en salud de la ciudad de Bucaramanga. Instrumentos, calidad de vida versión familiar y carga del cuidador. Análisis: se utilizó estadística descriptiva y el coeficiente de correlación lineal de Spearman. Resultados: los cuidadores familiares son en su mayoría mujeres, de estratos socioeconómicos bajos, ocupación hogar, una mediana de 18 horas día a la asistencia y cuidado, el estudio reportó una calidad de vida global percibida medio, con un promedio de 105.69, en cuanto a la carga del cuidado el 23,7% de los cuidadores presenta una sobrecarga severa, el 27,3% sobrecarga leve y el 49% no sobrecarga, de acuerdo con la clasificación establecida por Zarit. Se evidencia un coeficiente de correlación de Spearman de (-0,783) estadísticamente significativo con un valor de (P=0.00). Conclusión. Los hallazgos comprueban la existencia de una correlación positiva entre las variables descritas en los cuidadores familiares de personas con enfermedades respiratorias crónicas. (AU)

Objective: To establish the relationship between the burden of care and quality of life in family caregivers of people with chronic respiratory diseases Methods: Descriptive, correlational and cross-sectional quantitative approach. Attended by 55 family caregivers attending an institution of tertiary health care for the city of Bucaramanga. Instruments, quality of life and family version caregiver burden. Analysis: Descriptive statistics and correlation coefficient of Spearman was used. Results: Family caregivers are mostly women from low socioeconomic strata, home occupation, a median 18-hour assistance and day care, the study reported an average overall quality of life perceived, with an average of 105.69, as the burden of care for 23.7% of caregivers have severe overload, overload 27.3% mild and 49% do not overload, according to the classification established by Zarit. A correlation coefficient of Spearman (-0.783) with a value statistically significant (P = 0.00) is evident. Conclusion. The findings prove the existence of a positive correlation between the variables described in family caregivers of people with chronic respiratory diseases. (AU)

Pterocarpans from the root bark of Aeschynomene fascicularis.

A new pterocarpan, aeschynocarpin (1), and the known pterocarpan 2-methoxymedicarpin (2) were isolated for the first time from Aeschynomene fascicularis (Fabaceae) and their structures elucidated by means of spectroscopic {UV/Vis, IR, and NMR (1H, 13C, COSY, HMQC,and HMBC)} andmass spectrometric (EI-MS and HRCIMS) techniques. Both compounds were tested in vitro for their cytotoxic and antiproliferative activities against a panel of cancer cell lines. This is the first report on the presence of pterocarpans in the genus Aeschynomene.

Bonellia albiflora: A Mayan Medicinal Plant That Induces Apoptosis in Cancer Cells.

Few studies have been carried out on the medical flora of Mexico's Yucatan Peninsula in search for new therapeutic agents, in particular against cancer. In this paper, we evaluated the cytotoxic potential of the extract of Bonellia albiflora, a plant utilized in the traditional Mayan medicine for treatment of chronic injuries of the mouth. We carried out the methanolic extracts of different parts of the plant by means of extraction with the Soxhlet equipment. We conducted liquid-liquid fractions on each extract with solvents of increasing polarity. All extracts and fractions were evaluated for cytotoxic activity versus four human cancer cell lines and one normal cell line through a tetrazolium dye reduction (MTT) assay in 96-well cell culture plates. The methanolic root-bark extract possessed much greater cytotoxic activity in the human oropharyngeal cancer cell line (KB); its hexanic fraction concentrated the active metabolites and induced apoptosis with the activation of caspases 3 and 8. The results demonstrate the cytotoxic potential of the B. albiflora hexanic fraction and substantiate the importance of the study of the traditional Mayan medicinal plants.

Screening of plants used in Mayan traditional medicine to treat cancer-like symptoms.

AIM OF THE STUDY: To investigate the potential of plants used in Mayan traditional medicine to treat cancer-like symptoms using the Mayan ethnobotany literature, and evaluate their organic extracts for in vitro cytotoxic activity on cancer cell lines. MATERIALS AND METHODS: The selection of the plants studied in this investigation was based on the Mayan ethnobotanical information provided by different literature sources. Extracts were obtained by maceration with methanol for 72 h of each plant part used and evaporated in vacuo to give the corresponding dried extract. Each methanol extract was tested for its cytotoxicity using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay performed in 96-well tissue plates on seven cancer cell lines, lung carcinoma (A549), cervix adenocarcinoma (HeLa), laryngeal carcinoma (Hep-2), nasopharynx carcinoma (KB), breast adenocarcinoma (MCF-7), prostate adenocarcinoma (PC-3), and cervix squamous carcinoma cells (SiHa), as well as normal human embryonic kidney cell line (HEK-293). Cell proliferation/viability was spectrophotometrically assessed at 540 nm after addition of MTT. RESULTS: 51 plants were found in the literature to be used for the treatment of symptoms suggestive of cancer, 21 were chosen to evaluate the cytotoxic activity. Aeschynomene fascicularis root bark extract showed a pronounced cytotoxic activity on Hela and KB cell lines and Bonellia macrocarpa stem and root bark extracts showed similar prominent activities on KB cells. CONCLUSION: 21 plants were selected according to their use in the treatment of cancer-like symptoms recorded in the ethnobotanical literature. Plant extracts prepared from Aeschynomene fascicularis root bark and Bonellia macrocarpa stem and root bark have been selected for extensive studies leading to the isolation of the active constituents.

Estudio multicéntrico no comparativo de eficacia y seguridad de Cefepime en infecciones severas en unidades de cuidados intensivos (UCIs) en Venezuela / Study and eficacy of the security of Cefepime in severes infections at the intensive care (UCIs) en Venezuela

Las infecciones que comprometen la vida requieren antibioticoterapia efectiva antes de haber identificado al agente causal mediante cultivo o tinción, particularmente en las UCIs, por ello, es necesario conocer la efectividad y seguridad de antibióticos emergentes, como las cefalosporinas de cuarta generación. Con este objetivo, se reclutaron 299 pacientes mayores de 18 años de edad atendidos en la UCI con infecciones graves adquiridas en la comunidad o hospital. A todos se les admitió cefepime solo (38,13 por ciento) o en combinación con otro antibiótico (61,87 por ciento) obteniendo resolución clínica y bacteriológica, en 88,8 por ciento y 92,8 por ciento de casos, respectivamente. El tratamiento con cefepime, solo en combinación con otros antibióticos, es eficaz seguro en pacientes con infecciones moderadas y severas en unidades de cuidados intensivos en nuestro país

Hiperinsulinemia y alteraciones lipídicas en etapas tempranas de la hipertensión arterial esencial / Hyperinsulinemia and lipid alterations in the first stages of essential arterial hypertension

El propósito de este estudio fue evaluar la presencia de insulino-resistencia en pacientes no diabéticos y no obesos con hipertensión arterial esencial (HAE), de leve a moderada, de diagnóstico reciente y sin estar recibiendo tratamiento farmacológico. Asimismo, establecer posibles relaciones entre ese estado de insulino-resistencia y alteraciones en el metabolismo lipídico. Se estudiaron 21 controles (9 hombres y 12 mujeres) y 29 pacientes con HAE (19 hombres y 10 mujeres). El grupo control tuvo las siguientes características: edad promedio = 29,0 ñ 1,5 años; IMC = 23,9 ñ 0,46 kg/m2; presión sistólica = 112,6 ñ 2,9 y diastólica = 68,0 ñ mmHg, y los pacientes hipertensos: edad promedio = 35 ñ 1,4 años; IMC = 27,3 ñ 0,45 kg/m2 presión sistólica = 140 ñ 2,6 diastólica = 95,1 ñ 1,4 mmHg. A cada individuo se le practicó un análisis clínico y de laboratorio (perfil hipertensivo) para configurar el diagnóstico de HAE y descartar hipertensión secundaria. Los individuos fueron sometidos a una prueba de tolerancia glucosada oral (PTGO) con determinación de glucosa e insulina determinándosele además su perfil lipídico. La PTGO reveló en los pacientes con HAE un aumento significativo (p<0,05) en la concentración de glucosa basal así como durante toda la sobrecarga (30,60 y 120 min) cuando se comparó con el grupo control, acompañado también por concentraciones de insulina signifcativamente más elevadas (p<0,005) a nivel basal y a los 120 min después del inicio de la sobrecarga. La relación G/I resultó significativamente menor (p<0,05) en HAE tanto a nivel basal como a los 120 min, indicando una respuesta insulínica más pronunciada y a su vez no compensatoria pues la glicemia se mantuvo elevada. La principal alteración lipídica de los sujetos con HAE fue un incremento significativo en la concentraciones de colesterol, VLDL-colesterol. Estas alteraciones fueron especialmente manifiestas en el sexo masculino y en aquellos individuos que aunque obesos, presentaban sobrepeso (IMC = 27-29). Además se encontró en estos pacientes una asociación positiva y significativa entre la concentración de insulina basal y los valores de triglicéridos, VLDL-colesterol y la presión diastólica

La utilizacion de pozos absorbentes en la ciudad de La Paz

El presente trabajo pretende hacer un estudio de tasas depercolacion en diferentes zonas donde se hace necesario el uso de pozos de absorcion como destino final de las aguas negras debido fundamentalmente a la carencia de un sistema de alcantarillado. La zonificacion es otro objetivo que se persigue para dar una pauta a proyectistas y a personas interesadas en este problema, para lo cual es necesario hacer una investigacion de las tasas de percolacion de los suelos donde no existe una red de alcantarillado. La proyeccion del presente trabajo es dar soluciones, que alivien en forma temporal la contaminacion ambiental y la estética de las zonas suburbanas que en su totalidad presentan basurales y focos de contaminacion, donde las personas realizan sus necesidades biologicas.