ent-Beyerane Diterpenes as a Key Platform for the Development of ArnT-Mediated Colistin Resistance Inhibitors.

Colistin is a last-resort antibiotic for the treatment of multidrug resistant Gram-negative bacterial infections. Recently, a natural ent-beyerene diterpene was identified as a promising inhibitor of the enzyme responsible for colistin resistance mediated by lipid A aminoarabinosylation in Gram-negative bacteria, namely, ArnT (undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase). Here, semisynthetic analogues of hit were designed, synthetized, and tested against colistin-resistant Pseudomonas aeruginosa strains including clinical isolates to exploit the versatility of the diterpene scaffold. Microbiological assays coupled with molecular modeling indicated that for a more efficient colistin adjuvant activity, likely resulting from inhibition of the ArnT activity by the selected compounds and therefore from their interaction with the catalytic site of ArnT, an ent-beyerane scaffold is required along with an oxalate-like group at C-18/C-19 or a sugar residue at C-19 to resemble L-Ara4N. The ent-beyerane skeleton is identified for the first time as a privileged scaffold for further cost-effective development of valuable colistin resistance inhibitors.

Structural Elucidation and Antimicrobial Characterization of Novel Diterpenoids from Fabiana densa var. ramulosa.

Novel diterpenoids were isolated from the extracts of Fabiana densa var. ramulosa and found to display a selective activity against Gram-positive bacterial strains with negligible cytotoxicity toward human keratinocytes. This study highlighted the role played by the acidic group at C18 of the tetracyclic ent-beyerene scaffold for antibacterial effects and how the length and flexibility of the alkyl chain between the two carbonyl groups are crucial factors to increase the antimicrobial activity of the molecules, supporting the development of natural products from F. densa and their derivatives for treatment of microbial infections.

Effects of environment on human cytokine responses during childhood in the tropics: role of urban versus rural residence.

BACKGROUND: Environment may have a key role in the development of the immune system in childhood and environmental exposures associated with rural residence may explain the low prevalence of allergic and autoimmune diseases in the rural tropics. We investigated the effects of urban versus rural residence on the adaptive immune response in children living in urban and rural areas in a tropical region of Latin America. METHODS: We recruited school children in either rural communities in the Province of Esmeraldas or in urban neighborhoods in the city of Esmeraldas, Ecuador. We collected data on environmental exposures by questionnaire and on intestinal parasites by examination of stool samples. Peripheral blood leukocytes (PBLs) in whole blood were stimulated with superantigen, parasite antigens and aeroallergens and IFN-γ, IL-5, IL-10, IL-13, and IL-17 were measured in supernatants. RESULTS: We evaluated 440 school children; 210 living in rural communities and 230 in the city of Esmeraldas. Overall, urban children had greater access to piped water (urban 98.7 % vs. rural 1.9 %), were more likely to have a household bathroom (urban 97.4 % vs. rural 54.8 %), and were less likely to be infected with soil-transmitted helminth infections (urban 20.9 % vs. rural 73.5 %). Generally, detectable levels of cytokines were more frequent in blood from children living in urban than rural areas. Urban residence was associated with a significantly greater frequency of IL-10 production spontaneously (adjusted OR 2.56, 95 % CI 1.05-6.24) and on stimulation with Ascaris (adj. OR 2.5, 95 % CI 1.09-5.79) and house dust mite (adj. 2.24, 95 % CI 1.07-4.70) antigens. Analysis of effects of environmental exposures on SEB-induced IL-10 production within urban and rural populations showed that some environmental exposures indicative of poor hygiene (urban - higher birth order, A. lumbricoides infection; rural - no bathroom, more peri-domiciliary animals, and living in a wood/bamboo house) were associated with elevated IL-10. CONCLUSIONS: In our study population, the immune response of children living in an urban environment was associated more frequently with the production of the immune regulatory cytokine, IL-10. Some factors related to poor hygiene and living conditions were associated with elevated IL-10 production within urban and rural populations.

Urbanisation is associated with prevalence of childhood asthma in diverse, small rural communities in Ecuador.

BACKGROUND: Studies conducted in transitional communities from Africa and Asia have pointed to the process of urbanisation as being responsible for the increase in asthma prevalence in developing regions. In Latin America, there are few published data available on the potential impact of urbanisation on asthma prevalence. The aim of the present study was to explore how the process of urbanisation may explain differences in asthma prevalence in transitional communities in north-eastern Ecuador. METHODOLOGY/PRINCIPAL FINDINGS: An ecological study was conducted in 59 communities in Esmeraldas Province, Ecuador. Indicators of urbanisation were grouped into three indices representing the processes associated with urbanisation: socioeconomic, lifestyle and urban infrastructure. Categorical principal components analysis was used to generate scores for each index and a fourth index--a summary urbanisation index--was derived from the most representative variables in each of the three indices. The authors analysed the associations between community asthma prevalence and the indices, as well as with each indicator variable of every group. The overall prevalence of asthma was 10.1% (range 0-31.4% between communities). Three of the four indices presented significant associations with community asthma prevalence: socioeconomic (r = 0.295, p = 0.023), lifestyle (r = 0.342, p = 0.008) and summary urbanisation index (r = 0.355, p = 0.006). Variables reflecting better socioeconomic status and a more urban lifestyle were associated with greater asthma prevalence. CONCLUSIONS: These data provide evidence that the prevalence of asthma increases with increasing levels of urbanisation in transitional communities, and factors associated with greater socioeconomic level and changes towards a more urban lifestyle may be particularly important.

Immune system development during early childhood in tropical Latin America: evidence for the age-dependent down regulation of the innate immune response.

The immune response that develops in early childhood underlies the development of inflammatory diseases such as asthma and there are few data from tropical Latin America (LA). This study investigated the effects of age on the development of immunity during the first 5 years of life by comparing innate and adaptive immune responses in Ecuadorian children aged 6-9 months, 22-26 months, and 48-60 months. Percentages of naïve CD4+ T cells declined with age while those of memory CD4(+) and CD8(+) T cells increased indicating active development of the immune system throughout the first five years. Young infants had greater innate immune responses to TLR agonists compared to older children while regulatory responses including SEB-induced IL-10 and percentages of FoxP3(+) T-regulatory cells decreased with age. Enhanced innate immunity in early life may be important for host defense against pathogens but may increase the risk of immunopathology.

Biological activity of genistein and soy extracts: selective induction of some but not all estrogenic responses in the prepubertal rat uterus / Actividad biológica de Genisteína y extractos de soya: inducción selectiva de algunas pero no todas las respuestas estrogénicas en el útero de la rata prepúber

The existence of multiple kinds of estrogen receptors (ERs), involved in independent groups of responses, allows their dissociation and opens the possibility to selectively induce beneficial responses but not those considered at risk (cell proliferation). Based on the low hormone-dependent cancer mortality in Eastern Asia, attributed to high dietary intake of estrogenic isoflavones, we investigated whether genistein (G) or soybean extracts (S) selectively induce some, but not all estrogenic responses in the rat uterus, comparing its activity to that of estradiol-17 (E2). Prepubertal rats were treated with E2, G, concentrated S (Sc), diluted S (Sd), or vehicle, and uterine responses to estrogen were evaluated. Luminal epithelial and myometrial cell hypertrophy, and luminal epithelial RNA increase, were induced by E2, G or S. Uterine eosinophilia, endometrial edema and proliferation of 4 uterine cell-types were induced by E2 only. Results reveal that G and S induce some responses to estrogen but not others, suggesting their use as agents not displaying carcinogenic risk.

La existencia de múltiples tipos de receptores de estrógeno (ERs), involucrados en el desarrollo de grupos independientes de respuestas a estrógeno, permite su disociación y abre la posibilidad de inducir en forma selectiva respuestas benéficas pero no aquellas consideradas de riesgo (proliferación celular). Basado en la baja mortalidad por cánceres hormono-dependientes en el Este Asiático, atribuidos a una alta ingesta dietaria de isoflavonas estrogénicas, nosotros investigamos si la genisteína (G) o extractos de soja (S) inducen en forma selectiva algunas, pero no todas, las respuestas estrogénicas en el útero de rata, comparando su actividad con la del estradiol-17beta (E2). Ratas prepuberales fueron tratadas con E2, G, S concentrado (Sc), S diluido (Sd) o vehículo, y las respuestas estrogénicas en el útero fueron evaluadas. Las hipertrofias celulares en epitelio luminal y miometrio, y el aumento de ARN en células del epitelio luminal fueron inducidas por E2, G o S. La eosinofilia uterina, el edema en estroma endometrial y la proliferación de 4 tipos celulares uterinos fueron inducidos sólo por E2. Los resultados revelan que G y S inducen algunas respuestas estrogénicas pero no otras, sugiriendo su uso terapéutico como agentes estrogénicos que no presentan riesgo de cáncer.

Risk factors for atopic and non-atopic asthma in a rural area of Ecuador.

BACKGROUND Asthma has emerged as an important public health problem of urban populations in Latin America. Epidemiological data suggest that a minority of asthma cases in Latin America may be associated with allergic sensitisation and that other mechanisms causing asthma have been overlooked. The aim of the present study was to investigate risk factors for atopic and non-atopic asthma in school-age children. METHODS A cross-sectional study was conducted among 3960 children aged 6-16 years living in Afro-Ecuadorian rural communities in Esmeraldas province in Ecuador. Allergic diseases and risk factors were assessed by questionnaire and allergic sensitisation by allergen skin prick reactivity. RESULTS A total of 390 (10.5%) children had wheeze within the previous 12 months, of whom 14.4% had at least one positive skin test. The population-attributable fraction for recent wheeze associated with atopy was 2.4%. Heavy Trichuris trichiura infections were strongly inversely associated with atopic wheeze. Non-atopic wheeze was positively associated with maternal allergic symptoms and sedentarism (watching television (>3 h/day)) but inversely associated with age and birth order. CONCLUSIONS The present study showed a predominance of non-atopic compared with atopic wheeze among schoolchildren living in a poor rural region of tropical Latin America. Distinct risk factors were associated with the two wheeze phenotypes and may indicate different causal mechanisms. Future preventive strategies in such populations may need to be targeted at the causes of non-atopic wheeze.

Active metabolites from Dunalia spinosa resinous exudates.

Dunalia spinosa, a plant used in folk medicine for toothaches, breathing problems and cleansing wounds, was found active as antimicrobial and antioxidant. A new (E)-aurone rutinoside (dunaurone) has been isolated from the aerial parts of the plant, and its structure was determined by spectroscopic means. Lupeol, beta-sitosterol, scopoletin, quercetin and withaferin A were also found. All the extracts exhibited strong antimicrobial activity while dunaurone showed only weak antimicrobial inhibition against Klebsiella pneumoniae; in addition it presented a significant free radical scavenging activity.

Impact of long-term treatment with ivermectin on the prevalence and intensity of soil-transmitted helminth infections.

BACKGROUND: Control of soil-transmitted helminth (STH) infections relies on the periodic and long-term administration of anthelmintic drugs to high-risk groups, particularly school-age children living in endemic areas. There is limited data on the effectiveness of long-term periodic anthelmintic treatment on the prevalence of STHs, particularly from operational programmes. The current study investigated the impact of 15 to 17 years of treatment with the broad-spectrum anthelmintic ivermectin, used for the control of onchocerciasis, on STH prevalence and intensity in school-age and pre-school children. METHODS AND FINDINGS: A cross-sectional study was conducted in communities that had received annual or twice-annual ivermectin treatments and geographically adjacent communities that had not received treatment in two districts of Esmeraldas Province in Ecuador. Stool samples were collected from school-age children and examined for STH infection using the Kato-Katz and formol-ether concentration methods. Samples were collected also from pre-school children and examined by the formol-ether concentration method. Data on risk factors for STH infection were collected by parental questionnaire. We sampled a total of 3,705 school-age children (6-16 years) from 31 treated and 27 non-treated communities, and 1,701 pre-school children aged 0-5 years from 18 treated and 18 non-treated communities. Among school-age children, ivermectin treatment had significant effects on the prevalence (adjusted OR = 0.06, 95% CI 0.03-0.14) and intensity of Trichuris trichiura infection (adjusted RR = 0.28, 95% CI 0.11-0.70), but appeared to have no impact on Ascaris lumbricoides or hookworm infection. Reduced prevalence and intensities of T. trichiura infection were observed among children not eligible to receive ivermectina, providing some evidence of reduced transmission of T. trichiura infection in communities receiving mass ivermectin treatments. CONCLUSION: Annual and twice-annual treatments with ivermectin over a period of up to 17 years may have had a significant impact on T. trichiura infection. The present data indicate that the long-term control of onchocerciasis with ivermectin may provide additional health benefits by reducing infections with trichuriasis. The addition of a second anthelmintic drug such as albendazole may be useful for a long-term effect on A. lumbricoides infection.

¿Es posible encontrar un fitoestrógeno para la terapia de reemplazo hormonal, que disminuya el riesgo de cáncer?: tema de Proyecto Anillos de Investigación del Programa Bicentenario en Ciencia y Tecnología / Is it possible to find a phytoestrogen for hormone replacement therapy, decreasing cancer risk?: subject of Research Team Grant in Science and Technology from the Bicentennial Program in Science and Technology

Se describe una nueva línea de investigación que tiene como objetivo investigar principios activos presentes en especies vegetales chilenas, para identificar alguna(s) que produzcan los efectos farmacológicos deseables para su uso como terapia de reemplazo hormonal en mujeres peri o postmenopáusicas, pero que no aumenten, o incluso disminuyan, el riesgo de desarrollar cáncer mamario o endometrial. Esta posibilidad se basa en el hallazgo previo de nuestro equipo de investigadores de un nuevo tipo de receptores estrogénicos responsables de respuestas estrogénicas no genómicas y de nuestro hallazgo de diferencias entre los receptores estrogénicos citosólico-nucleares clásicos de los diferentes tipos celulares uterinos. Si existiera, como anteriormente se creía, un solo tipo de receptor de estrógenos, no sería posible el desarrollo de este nuevo fármaco estrogénico selectivo que buscamos, pues todos los receptores tendrían la misma afinidad por este agente, el que en consecuencia, induciría todas las respuestas a la estimulación estrogénica (incluyendo aquellas que deseamos prevenir, como las que presentan riesgo de desarrollo de cáncer), o que actuaría como antiestrógeno, antagonizando todas las respuestas a los estrógenos en el útero.

A new research line aimed at the investigation of active agents from Chilean plant species is described. The purpose is to indentify those agents inducing expected pharmacological effects in a hormone replacement therapy in peri- or post-menopausal women, but not increasing, or even decreasing, the risk for development of mammary or endometrial cancer. This possibility is based on previous findings from our research team of a new kind of estrogen receptors, responsible of non-genomic responses to estrogen, and our finding of differences between the classical cytosol-receptor estrogen receptors from the different uterine cell-types. If there exists one kind of estrogen receptors only in the uterus, as it was formerly accepted, then it is not possible to develop the selective estrogenic drug we search for, because all receptors would display the same affinity for this agent; therefore, it would induce all responses to estrogen stimulation (including those we wish to prevent, such as those presenting risk of cancer development), or would act as antiestrogen, antagonizing all responses to estrogen in the uterus.

Brote de histeria epidémica entre estudiantes de secundaria en San Juancito Francisco Morazán, Honduras / Outbreak of epidemic hysteria among middle school students in San Juancito, Francisco Morazán, Honduras

Objetivos: Describir un brote de enfermedad psicogénica en masa entre estudiantes de secundaria, determinar los factores de riesgo y las medidas de control. MATERIAL Y MÉTODOS. Se llevo a cabo un estudio de casos y controles. Se realizaron análisis químicos y bacteriológicos del agua, suelo, productos agrícolas e ingredientes de los alimentos consumidos el día del brote. Se efectuaron determinaciones de colinesterasa sérica entre los casos agudo se inspecciones ambientales del área. RESULTADOS. 89 sujetos fueron entrevistados durante la investigación. La tasa de ataque fue de 48,3%(43 casos). Una tercera parte de los afectados percibieron un olor desagradable que fue el factor desencadenante del brote(OR = 26,67; IC95%: 3,31 a 579,25). En el cuadro clínico predominó: la cefalea (86,0%), dolor epigástrico(76,7%) y mareos (74,4%). Nueve pacientes fueron hospitalizados y la evolución fue satisfactoria. Los estudios bacteriológicos y químicos realizados fueron negativos. Las determinaciones de colinesterasa sérica y las inspecciones ambientales fueron también negativas. DISCUSIÓN. Los hallazgos clínicos, epidemiológicos y laboratoriales fueron consistentes con el diagnóstico de enfermedad psicogénica en masa. CONCLUSIÓN. El reconocimiento temprano de esta entidad clínica y los factores precipitantes permitió la toma de decisiones acertadas en el manejo y control de este problema...

Brote de histeria epidémica entre estudiantes de secundaria en San Juancito Francisco Morazán, Honduras / Outbreak of epidemic hysteria among middle school students in San Juancito, Francisco Morazán, Honduras

Objetivos Describir un brote de enfermedad psicogénica en masa entre estudiantes de secundaria, determinar los factores de riesgo y las medidas de control. MATERIAL Y MÉTODOS. Se llevo a cabo un estudio de casos y controles. Se realizaron análisis químicos y bacteriológicos del agua, suelo, productos agrícolas e ingredientes de los alimentos consumidos el día del brote. Se efectuaron determinaciones de colinesterasa sérica entre los casos agudo se inspecciones ambientales del área. RESULTADOS. 89 sujetos fueron entrevistados durante la investigación. La tasa de ataque fue de 48,3%(43 casos). Una tercera parte de los afectados percibieron un olor desagradable que fue el factor desencadenante del brote(OR = 26,67; IC95%: 3,31 a 579,25). En el cuadro clínico predominó: la cefalea (86,0%), dolor epigástrico(76,7%) y mareos (74,4%). Nueve pacientes fueron hospitalizados y la evolución fue satisfactoria. Los estudios bacteriológicos y químicos realizados fueron negativos. Las determinaciones de colinesterasa sérica y las inspecciones ambientales fueron también negativas. DISCUSIÓN. Los hallazgos clínicos, epidemiológicos y laboratoriales fueron consistentes con el diagnóstico de enfermedad psicogénica en masa. CONCLUSIÓN. El reconocimiento temprano de esta entidad clínica y los factores precipitantes permitió la toma de decisiones acertadas en el manejo y control de este problema... (AU)

Topical anti-inflammatory activity of 2alpha-hydroxy pentacyclic triterpene acids from the leaves of Ugni molinae.

Leaf extracts of Ugni molinae Turcz. are used in the Chilean cosmetic industry on the assumption that they have decongestant, regenerative, and anti-aging properties. A bioassay-guided fractionation of this plant material showed that some extracts have potent anti-inflammatory activities. Further fractionation led to the isolation and identification of betulinic acid, a mixture of ursolic and oleanolic acids, and the 2alpha-hydroxy derivatives alphitolic, asiatic, and corosolic acids. The latter three were evaluated in vivo in the mouse ear assay for their topical anti-inflammatory activity, inducing inflammation with either arachidonic acid (AA) or 12-O-tetradecanoylphorbol-13 acetate (TPA). Only corosolic acid was active in the AA assay, with similar potency to nimesulide, but all three triterpene acids inhibited TPA-induced inflammation with potencies comparable to that of indomethacin.

Constituents and biological activities of Schinus polygamus.

The folk medicine employs Schinus polygamus to treat arthritic pain and cleansing of wounds. As no reports of pharmacological studies supporting its anti-inflammatory and analgesic properties, extracts of increasing polarity were assayed on the base of fever, pain and inflammation, together with its antimicrobial activity. All the extracts showed pharmacological activities. From the most active extracts different metabolites were isolated that can in part explain the antipyretic, anti-inflammatory, and analgesic activity: beta-sitosterol, shikimic acid together with quercetin, previously reported. Also, the essential oil of leaves and fruits was obtained and compared with the oil obtained from Schinus polygamus collected in Argentine. Oils differed in composition and in antibacterial activity, where the Chilean species exhibited a wide spectrum of activity against Gram-positive and Gram-negative bacteria, and the most abundant compound found in leaves and fruits was beta-pinene, meanwhile the Argentine species showed high activity against Bacillus cereus, and the main components resulted to be alpha-phellandrene and limonene.

Two new dammarane triterpenoids from Kageneckia angustifolia D. Don.

Two new dammarane triterpenoids, 20R,21-epoxydammar-24-ene-3,23-dione and 20R,21-epoxy-3beta-hydroxydammar-24-ene-23-one have been isolated from the aerial parts of Kageneckia angustifolia D. Don, Rosaceae, along with the previously reported triterpenoids oleanolic acid and 3beta-(beta-D-glucosyloxy)-16alpha,23alpha-epoxycucurbita-5,24-dien-11-one and the phenolic prunasin. The structures of these compounds were established by MS, 1D- and 2D-NMR experiments, and the structure of the new compounds were confirmed by X-ray diffraction analysis.

Antimicrobial activity of isopteropodine.

Bioassay-directed fractionation for the determination of antimicrobial activity of Uncaria tomentosa, has led to the isolation of isopteropodine (0.3%), a known Uncaria pentacyclic oxindol alkaloid that exhibited antibacterial activity against Gram positive bacteria.

Constituents and biological activities from Muehlenbeckia hastulata.

Muehlenbeckia hastulata (J. E.Sm.) Johnst. used mainly for its abortive properties was found active for oxytoxic and analgesic activities in a biological activity screening (oxytoxic, analgesic, antimicrobial, cytotoxic and xanthine oxidase assay). Epicatechin, emodin-8-glycoside and rutin were isolated from the aerial part and the root of the plant.

Antibacterial diterpenoids from Fabiana densa var. ramulosa.

A biologically monitored fractionation of the resinous exudate of Fabiana densa Remy var. ramulosa Wedd. led to the isolation of the two new diterpenes: ent-beyer-15-en-18-O-succinate and ent-beyer-15-en-18-O-oxalate as the unique compounds responsible for the observed antibacterial activity of this extract. Their structures were determined by 1D and 2D NMR spectroscopy.

Pharmaco-toxicological study of Kageneckia oblonga, Rosaceae.

The probable antipyretic, antiinflammatory, analgesic and antioxidant properties of Kageneckia oblonga, Rosaceae, were investigated and the major compounds of its active extracts were isolated. The study comprised the acute toxicity of the extracts of global methanol, hexane, dichloromethane and methanol. The cytotoxicity of global methanol extract was studied in three tumoral cell lines. All the extracts exhibited the pharmacological activities under study. Methanol and dichloromethane were the most toxic extracts. From the global methanol extract, isolations were performed of prunasin, 23,24- dihydro-cucurbitacin F, and a new cucurbitacin, 3beta-(beta-D-glucosyloxy)-16alpha,23alpha-epoxycucurbita-5,24-diene-11-one. The cytotoxicity of both cucurbitacins on human neutrophils at the assayed concentrations was not statistically significant. In-vitro assays showed that both cucurbitacins can be partly responsible for the analgesic, antipyretic, and anti-inflammatory activities. Evaluation was done of the cytotoxicity of global methanol extract, 23, 24-dihydrocucurbitacin F, aqueous extracts and prunasin against P-388 murine leukaemia, A-549 human lung carcinoma and HT-29 colon carcinoma. Since global methanol extract presented a strong cytotoxicity against P-388 murine leukaemia, A-549 human lung carcinoma, and HT-29 cell lines, it is highly probable that this extract contain one or more cytotoxic compounds that could be investigated for their potential use as an agent against cancer.

Methyl psilalate: a new antimicrobial metabolite from Psila boliviensis.

Psila boliviensis (Wedd.) Cabr. yielded a new phenylpropanoid, named methyl psilalate. The structure was established by means of standard spectroscopic techniques. The microbiological evaluation of the compound revealed antibacterial activity against Gram-positive and Gram-negative bacteria.