Minicells as an Escherichia coli mechanism for the accumulation and disposal of fluorescent cadmium sulphide nanoparticles.

BACKGROUND: Bacterial biosynthesis of fluorescent nanoparticles or quantum dots (QDs) has emerged as a unique mechanism for heavy metal tolerance. However, the physiological pathways governing the removal of QDs from bacterial cells remains elusive. This study investigates the role of minicells, previously identified as a means of eliminating damaged proteins and enhancing bacterial resistance to stress. Building on our prior work, which unveiled the formation of minicells during cadmium QDs biosynthesis in Escherichia coli, we hypothesize that minicells serve as a mechanism for the accumulation and detoxification of QDs in bacterial cells. RESULTS: Intracellular biosynthesis of CdS QDs was performed in E. coli mutants ΔminC and ΔminCDE, known for their minicell-producing capabilities. Fluorescence microscopy analysis demonstrated that the generated minicells exhibited fluorescence emission, indicative of QD loading. Transmission electron microscopy (TEM) confirmed the presence of nanoparticles in minicells, while energy dispersive spectroscopy (EDS) revealed the coexistence of cadmium and sulfur. Cadmium quantification through flame atomic absorption spectrometry (FAAS) demonstrated that minicells accumulated a higher cadmium content compared to rod cells. Moreover, fluorescence intensity analysis suggested that minicells accumulated a greater quantity of fluorescent nanoparticles, underscoring their efficacy in QD removal. Biosynthesis dynamics in minicell-producing strains indicated that biosynthesized QDs maintained high fluorescence intensity even during prolonged biosynthesis times, suggesting continuous QD clearance in minicells. CONCLUSIONS: These findings support a model wherein E. coli utilizes minicells for the accumulation and removal of nanoparticles, highlighting their physiological role in eliminating harmful elements and maintaining cellular fitness. Additionally, this biosynthesis system presents an opportunity for generating minicell-coated nanoparticles with enhanced biocompatibility for diverse applications.

Pseudomonas violetae sp. nov. and Pseudomonas emilianonis sp. nov., two new species with the ability to degrade TNT isolated from soil samples at Deception Island, maritime Antarctica.

Two motile, rod-shaped, Gram-stain-negative bacterial strains, TNT11T and TNT19T, were isolated from soil samples collected at Deception Island, Antarctica. According to the 16S rRNA gene sequence similarity, both strains belong to the genus Pseudomonas. Further genomic analyses based on ANI and dDDH suggested that these strains were new species. Growth of strain TNT11T is observed at 0-30 â„ƒ (optimum, 20 â„ƒ), pH 4.0-9.0 (optimum, pH 6.0) and in the presence of 0-5.0% NaCl (optimum, 1% NaCl), while for TNT19T is observed at 0-30 â„ƒ (optimum between 15 and 20 â„ƒ), pH 5.0-9.0 (optimum, pH 6.0) and in the presence of 0-5.0% NaCl (optimum between 0 and 1% NaCl). The fatty acid profile consists of the major compounds; C16:0 and C16:1 ω6 for TNT11T, and C16:0 and C12:0 for TNT19T. Based on the draft genome sequences, the DNA G + C content for TNT11T is 60.43 mol% and 58.60 mol% for TNT19T. Based on this polyphasic study, TNT11T and TNT19T represent two novel species of the genus Pseudomonas, for which the proposed names are Pseudomonas violetae sp. nov. and Pseudomonas emilianonis sp. nov., respectively. The type strains are Pseudomonas violetae TNT11T (= RGM 3443T = LMG 32959T) and Pseudomonas emilianonis TNT19T (= RGM 3442T = LMG 32960T). Strains TNT11T and TNT19T were deposited to CChRGM and BCCM/LMG with entry numbers RGM 3443/LMG 32959 and RGM 3442/LMG 32960, respectively.

Arthrobacter vasquezii sp. nov., isolated from a soil sample from Union Glacier, Antarctica.

A Gram-stain-positive, catalase-positive, non-motile bacteria, with a rod-coccus cycle (designated as EH-1B-1T) was isolated from a soil sample from Union Glacier in Ellsworth Mountains, Antarctica. Strain EH-1B-1T had an optimal growth temperature of 28 °C and grew at pH 7-10. The major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0, C16 : 0 and anteiso-C17 : 0. The G+C content based on the whole genome sequence was 63.1 mol%. Strain EH-1B-1T was most closely related to members of the genus Arthrobacter, namely Arthrobacter subterraneus and Arthrobacter tumbae. The strain grew on tryptic soy agar, Reasoner's 2A agar, lysogeny broth agar and nutrient agar. The average nucleotide identity and digital DNA-DNA hybridization values between strain EH-1B-1T and its closest reference type strains ranged from 78 to 88 % and from 20.9 to 36.3 %, respectively. Based on phenotypic, chemotypic and genotypic evidence, it is proposed that strain EH-1B-1T represents a novel species of Arthrobacter, for which the name Arthrobacter vasquezii sp. nov. is proposed, with strain EH-1B-1T (RGM 3386T=LMG 32961T) as the type strain.

Inequity in mortality rates and potential years of life lost caused by COVID-19 in the Greater Santiago, Chile.

Several studies have shown that, in Chile, income inequality is relevant in explaining health inequities. The COVID-19 pandemic has also had a negative impact, with higher mortality rates in those municipalities of Greater Santiago with lower socioeconomic status. We study inequity in mortality based on Potential Years of Life Lost (PYLL) in 34 urban municipalities of the Metropolitan Region (Greater Santiago) and analyze its evolution between 2018 and 2021 and by COVID-19 waves. To compare the results obtained for PYLL, we also computed the mortality rates adjusted by direct standardization. In addition, we used the concentration index (CI) to measure the health inequalities between municipalities. In the first year of the pandemic, the absolute PYLL and the standardized mortality rate for all causes of death showed an increase of 13.6% and 18.9%, respectively. Moreover, 409,086 years of life were prematurely lost in 2020, one-fifth of them due to COVID-19. The concentration indices confirm inequality in both mortality rates and PYLL, where it is more pronounced when calculating the latter measure. Results show that the deaths due to the COVID-19 pandemic affected the most economically disadvantaged municipalities, and particularly young people in those places.

Solid medium for the direct isolation of bacterial colonies growing with polycyclic aromatic hydrocarbons or 2,4,6-trinitrotoluene (TNT).

Isolation of hydrocarbon-degrading bacteria is a key step for the study of microbiological diversity, metabolic pathways, and bioremediation. However current strategies lack simplicity and versatility. We developed an easy method for the screening and isolation of bacterial colonies capable of degrading hydrocarbons, such as diesel or polycyclic aromatic hydrocarbons (PAHs), as well as the pollutant explosive, 2,4,6-trinitrotoluene (TNT). The method uses a two-layer solid medium, with a layer of M9 medium, and a second layer containing the carbon source deposited through the evaporation of ethanol. Using this medium we grew hydrocarbon-degrading strains, as well as TNT-degrading isolates. We were able to isolate PAHs-degrading bacterial colonies directly from diesel-polluted soils. As a proof of concept, we used this method to isolate a phenanthrene-degrading bacteria, identified as Acinetobacter sp. and determined its ability to biodegrade this hydrocarbon.

Impact of e-cigarettes use on the oral health-related quality of life among young people in metropolitan Lima / Impacto en la calidad de vida relacionada a la salud oral del uso de cigarrillos electrónicos en los jóvenes de Lima metropolitana

Aim: To determine the effects of e-cigarette use on oral health-related quality of life (OHRQOL) in young people in Metropolitan Lima. Materials and Methods: This observational, analytical and cross-sectional study was performed with 189 individuals (age, 18­29 years) who used electronic cigarettes. The OHIP-Sp5 instrument was used to assess OHRQOL. Results: The use of e-cigarettes was higher among male participants (47.79%) than that among the female participants (26.32%). The mean OHRQOL scores of individuals who did and did not use e-cigarettes were 3.17 (2.26) and 3.12 (2.47), respectively These scores for people who did and did not use mouthwash were 2.92 (2.34) and 3.57 (2.43), respectively. Regarding orofacial pain 2.65% participants frequently re-ported "painful discomfort" and 7.41% of the young people presented such discomfort of orofacial aspect "frequently." Conclusions: Recording e-cigarette uses and frequency in patients' medical records is important, as well as incorporating educational strategies to reduce e-cigarette consumption and avoiding harmful effects on general health.

Objetivo: Evaluar el impacto en la calidad de vida relacionada a la salud oral del uso de cigarrillos electrónicos en los jóvenes de Lima Metropolitana. Materiales y Métodos: Se realizó un estudio observacional, analítico y transversal en un total de 189 jóvenes con edades comprendidas de 18 a 29 años que son usuarios de cigarrillos electrónicos. Para evaluar la calidad de vida relacionada a la salud oral se utilizó el instrumento "OHIP-Sp5". Resultados: Se determinó que los participantes del sexo masculino (47.79%) son los que más utilizan el cigarrillo electrónico en comparación a las participantes del sexo femenino (26.32%). Se observó una calidad de vida relacionada a la salud oral media de 3,17 (2,26) para los usuarios de cigarrillos electrónicos, mientras que para los no usuarios de cigarrillos electrónicos la media fue de 3,12 (2,47). Asimismo, para los que usan enjuagues bucales se encontró una media de 2.92(2.34), a diferencia de los que no hacían uso del mismo que presentaban peor calidad de vida relacionada con la salud oral con una media de 3.57(2.43). En cuanto a dolor orofacial el 2.65% de los participantes referían "molestias dolorosas" a menudo y el 7.41% de los jóvenes presentaban dicho disconfort de la apariencia orofacial "a menudo". Conclusión: El registro del uso y frecuencia del cigarrillo electrónico en la historia clínica de los pacientes es de suma importancia, así como incorporar estrategias educativas para reducir el consumo de los vapeadores y evitar efectos nocivos en la salud general.

COVID-19 en Chile: análisis de su impacto por olas y regiones

Background: The effects of COVID-19 in Chile changed over time and among regions. Aim: To identify patterns in the impact and evolution of COVID-19 for each wave generated between 2020 and 2022 at the 16 regions of the country. Material and Methods: Several indicators related to the pandemic, their evolution and their consequences for the health system and the health of the population were calculated. Results: There are differences in the evolution of the infection across the regions of the country, as well as heterogeneity between waves. Specifically, the second wave in Chile was identified as the one with the greatest impact, with a national death rate of 123.5 deaths per 100,000 inhabitants and 66.4% intensive care unit occupancy rate due to COVID-19. Performing a geographic analysis, it was possible to find systematic patterns, for example, between regions with higher immunization rates and lower rates of lethality, such as the cases of Ñuble and Atacama regions. Conclusions: These results emphasize the need to consider regional differences and the temporal context for the elaboration of strategies to the efficient management of a pandemic.

[The impact of the different waves of COVID-19 pandemic in Chile across regions]. / COVID-19 en Chile: análisis de su impacto por olas y regiones.

BACKGROUND: The effects of COVID-19 in Chile changed over time and among regions. AIM: To identify patterns in the impact and evolution of COVID-19 for each wave generated between 2020 and 2022 at the 16 regions of the country. MATERIAL AND METHODS: Several indicators related to the pandemic, their evolution and their consequences for the health system and the health of the population were calculated. RESULTS: There are differences in the evolution of the infection across the regions of the country, as well as heterogeneity between waves. Specifically, the second wave in Chile was identified as the one with the greatest impact, with a national death rate of 123.5 deaths per 100,000 inhabitants and 66.4% intensive care unit occupancy rate due to COVID-19. Performing a geographic analysis, it was possible to find systematic patterns, for example, between regions with higher immunization rates and lower rates of lethality, such as the cases of Ñuble and Atacama regions. CONCLUSIONS: These results emphasize the need to consider regional differences and the temporal context for the elaboration of strategies to the efficient management of a pandemic.

Seasonal Distribution of the Broad-Tailed Hummingbird (Selasphorus platycercus): A Climatic Approach.

The seasonal movements of birds are a phenomenon that has historically been of interest in ecology and biogeography. Despite this, information on how environmental conditions influence migratory behavior and its regulation is still scarce. In this work, we study the Broad-Tailed hummingbird Selasphorus platycercus from an analysis of its populations through longitudinal and latitudinal gradients. We use the frequencies of monthly presence records throughout the annual cycle to identify the breeding areas (corresponding to the summer months), of winter presence (corresponding to the winter months), and annual residence (presence records throughout the year). Subsequently, we use ecological niche models to reconstruct the potential distribution of the summer and winter niches by correlating the climates of each season with the corresponding records. We evaluate the species' climatic preferences between the breeding and winter seasons by transferring the niches from each season to the opposite and by their capacity to inter-predict records between seasons. In addition, we quantify the overlap between the summer and winter niches using a niche similarity analysis. Geographically, we see a clear seasonal turnover pattern along a north-south gradient and records throughout the year (resident populations) in the south-central region of its distribution. We observed a low inter-prediction of records between seasons. Together with the similarity analysis, we suggest that the species is niche-switching (i.e., has different seasonal niches). We identified three seasonal migration patterns among the species' populations: long-distance migratory, short-distance summer migrant, and resident. Our findings suggest that the different migration patterns in this species' populations all over its distribution can be explained through seasonal climatic variations throughout the year.

Processed meat consumption and associated factors in Chile: A cross-sectional study nested in the MAUCO cohort.

Processed meat consumption is increasing in Latin America. While in developed countries processed meat consumption has been associated with cardiovascular diseases and cancer, our region lacks data associated to its consumption and health impact. We characterized processed meat intake and associated factors in a population-based cohort of a Chilean agricultural county, MAUCO. We analyzed baseline dietary data of 7,841 participants, 4,358 women and 3,483 men (38-77 years), who answered an adapted Mediterranean index food frequency questionnaire. Eight percent of the participants presented high processed meat consumption (≥5 times per week). We explored associations of processed meat consumption with participant characteristics using multinomial logistic regression models. Main factors associated with higher consumption were being men, younger and currently employed, and having a high intake (>4 times per week) of red meat (Odds ratio, 2.71, 95% CI 2.10-3.48), butter/cream (1.96, 1.60-2.41), whole-fat dairy products (1.32, 1.04-1.67) and a high intake (≥1 time per day) of sugary snacks/sweets (2.49, 2.04-3.03) and sugary drinks (1.97, 1.63-2.38). Processed meat consumption associated to chronic diseases, particularly cardiovascular disease (Prevalence ratio, 2.28, 95% CI 1.58-3.29). Obesity mediated this association in a proportion of 5.0%, whereas for diabetes the proportion was 13.9%. In this population, processed meat was associated with other unhealthy dietary and lifestyle factors, as well as with chronic diseases, particularly cardiovascular disease.

Factors associated with change in adherence to COVID-19 personal protection measures in the Metropolitan Region, Chile.

Personal protective measures such use of face masks, hand washing and physical distancing have proven to be effective in controlling the spread of the Covid-19 pandemic. However, adherence to these measures may have been relaxed over time. The objective of this work is to assess the change in adherence to these measures and to find factors that explain the change For this purpose, we conducted a survey in the Metropolitan Region of Chile in which we asked the adherence to these measures in August-September 2021 and retrospectively for 2020. With the answers obtained we fit a logistic regression model in which the response variable is the relaxation of each of the self-care preventive actions. The explanatory variables used are socio-demographic characteristics such as the age, sex, income, and vaccination status of the respondents. The results obtained show that there has been a significant decrease in adherence to the three personal protection measures in the Metropolitan Region of Chile. In addition, it was observed that younger people are more likely to relax these measures. The results show the importance of generating new incentives for maintaining adherence to personal protection measures.

Identification of COVID-19 Waves: Considerations for Research and Policy.

The identification of COVID-19 waves is a matter of the utmost importance, both for research and decision making. This study uses COVID-19 information from the 52 municipalities of the Metropolitan Region, Chile, and presents a quantitative method-based on weekly accumulated incidence rates-to define COVID-19 waves. We explore three different criteria to define the duration of a wave, and performed a sensitivity analysis using multivariate linear models to show their commonalities and differences. The results show that, compared to a benchmark definition (a 100-day wave), the estimations using longer periods of study are worse in terms of the model's overall fit (adjusted R2). The article shows that defining a COVID-19 wave is not necessarily simple, and has consequences when performing data analysis. The results highlight the need to adopt well-defined and well-justified definitions for COVID-19 waves, since these methodological choices can have an impact in research and policy making.

A strategy to impute age at onset of a particular condition from external sources.

A key hypothesis in epidemiological studies is that time to disease exposure provides relevant information to be considered in statistical models. However, the initiation time of a particular condition is usually unknown. Therefore, we developed a multiple imputation methodology for the age at onset of a particular condition, which is supported by incidence data from different sources of information. We introduced and illustrated such a methodology using simulated data in order to examine the performance of our proposal. Then, we analyzed the association of gallstones and fatty liver disease in the Maule Cohort, a Chilean study of chronic diseases, using participants' risk factors and six sources of information for the imputation of the age-occurrence of gallstones. Simulated studies showed that an increase in the proportion of imputed data does not affect the quality of the estimated coefficients associated with fully observed variables, while the imputed variable slowly reduces its effect. For the Chilean study, the categorized exposure time to gallstones is a significant variable, in which participants who had short and long exposure have, respectively, 26.2% and 29.1% higher chance of getting a fatty liver disease than non-exposed ones. In conclusion, our multiple imputation approach proved to be quite robust both in the linear/logistic regression simulation studies and in the real application, showing the great potential of this methodology.

Polypharmacy in a semirural community in Chile: Results from Maule Cohort.

PURPOSE: Although polypharmacy in younger populations is a growing public health concern, most studies addressing polypharmacy focus on elderly populations. Thus, polypharmacy is not yet well understood in younger populations. METHODS: Baseline data from the Maule Cohort (MAUCO) (adults aged 38-74 years) were used to study the prevalence of polypharmacy and associated participant characteristics using logistic and zero-inflated negative binomial regressions. Factors studied include age, sex, self-rated health, education, smoking, obesity, diabetes, hypertension, and other chronic conditions. RESULTS: Polypharmacy was reported by 10% of participants overall, with higher prevalence among older (≥60 years) vs middle aged (<60 years) participants (overall: 20.9% vs 6.0%, P < .0001; for those reporting any medication use: 30.2% vs 15.9%, P < .0001). Middle-aged adults reported different patterns of medication use by polypharmacy status, while older adults reported similar medication use patterns regardless of polypharmacy. Diabetes, hypertension, dyslipidemia, cardiovascular diseases, hypothyroidism, and osteomuscular diseases were significantly associated with polypharmacy. Analyses also revealed that there are MAUCO participants who are potentially being undertreated for conditions like depression. CONCLUSIONS: Research into medication use among younger and middle-aged adults and development of possible tools to deprescribe medications in this population are warranted. However, it is important that patients who need treatment receive it, and so both potential overtreatment and undertreatment need further study in this population.

[Effectiveness and tolerability of low volume bowel cleansing polyethylene glycol solution for colonoscopy]. / Eficacia y tolerabilidad de la reducción del volumen de polietilenglicol para la preparación para colonoscopia.

BACKGROUND: A successful colonoscopy depends, among other factors, on a proper colon cleansing. This variable also affects the acceptance of the patient to carry out the study. AIM: To analyze the efficacy and tolerability of a low volume polyethylene glycol formulation (2 liters), compared to the conventional presentation of 4 liters. MATERIAL AND METHODS: Patients referred for a colonoscopy were randomly divided to receive either two or four liter of polyethylene glycol as bowel cleansing, which was assessed using the Boston score. Raters of the latter were blinded to the volume of polyethylene glycol that the patients used. RESULTS: Seventy-four patients participated in the study. Subjects who received a 4 liters preparation had an average Boston score of 7.78, versus 8.16 for patients who received a volume of 2 liters (p = 0.267). No significant differences in tolerability were observed between both groups. No significant differences in the efficacy and tolerability between a conventional or a reduced volume of polyethylene glycol solution for the preparation of a colonoscopy were observed. These findings may be especially important for subgroups of patients with difficulties for oral administration of fluids.

Biogeografía del tomate Solanum lycopersicum var. cerasiforme (Solanaceae) en su centro de origen (sur de América) y de domesticación (México)

El tomate (Solanum lycopersicum) es una de las principales hortalizas en el mundo debido a las importantes ganancias económicas que genera su comercialización; sin embargo, a pesar de que la especie es ampliamente cultivada en el mundo, su diversidad genética se considera restringida. Esto hace que su resistencia a plagas y enfermedades en las variedades actualmente cultivadas sea baja. Existe la forma silvestre S. l. var ceraciforme que se distribuye desde Suramérica (centro de origen) hasta México (área de domesticación), específicamente en la vertiente del Golfo de México en Veracruz. Como objetivo, se quiso identificar patrones de diversificación ambiental con los que se pudiesen inferir procesos de adaptación de las poblaciones en el área de domesticación con respecto a su centro de origen. Asimismo, se planteó proponer medidas de conservación y rescate del tomate S. l. var. cerasiforme. Se realizaron modelos de nicho ecológico (MNE) con Maxent versión 3.4.1 (evaluados con AUC y ROC-parcial) para determinar la idoneidad de las condiciones ambientales, incluyendo proyecciones del centro de domesticación al área de origen y viceversa. Esto se realizó con base en ocho variables de temperatura y precipitación. Los registros de tomate fueron tomados de fuentes bibliográficas y trabajo de campo. Seguidamente, se realizó la prueba de comparación de nichos (equivalencia y similitud), propuesta por Broennimann et al. (2012), para evaluar la similitud de condiciones ambientales en ambas regiones. Posteriormente, se realizó un análisis de varianza seguido de una prueba de comparación de medias (Tukey, P ≤ 0.05) con las ocho variables ambientales utilizadas. Los valores de AUC (0.93 y 0.80) y ROC-parcial obtenidos (1.86 y 1.71; P = 0.0001) de los MNE muestran que fueron buenos modelos predictores. Se observó que en el centro de México existen condiciones ambientales similares a las del centro de origen, a diferencia de la vertiente del Golfo de México donde son diferentes. La prueba de equivalencia mostró que la comparación ambiental entre ambas regiones es menos equivalente que lo esperado por azar (P = 0.003). Mientras tanto, la otra prueba indica que la similitud que existe entre ambas regiones también se puede obtener por azar (P = 0.683). También, se encontraron diferencias significativas en tres variables de temperatura y precipitación. En conclusión, el centro de origen y de domesticación de S. l. var. cerasiforme tienen características ambientales en común a pesar de la distancia geográfica, pero existen zonas geográficas (vertiente del Golfo de México en Veracruz) en el área de domesticación con condiciones ambientales diferentes a las de su centro de origen y con un potencial importante como bancos de germoplasma.

The tomato (Solanum lycopersicum) is one of the main horticultural crops in the world because of the important economic benefits that its commercialization generates. Even though the species is widely cultivated in the world, it is susceptible to pests, diseases, and environmental stresses due to the loss of its genetic diversity. There is a wild form called S. l. var ceraciforme that is distributed from South America (its center of origin) to Mexico (its area of domestication), specifically on the slope of the Gulf of Mexico in Veracruz. Due to the large genetic diversity of these wild tomatoes, it is important to improve its crop. The objective of this investigation was to identify patterns of environmental diversification of the tomato, infer the processes of adaptation of the populations in the area of domestication with respect to their center of origin and propose measures of conservation and variation of S. l. var. cerasiforme. We generated two ecological niche models (MNE) with Maxent version 3.4.1 (evaluated with AUC and partial-ROC) to determine the suitability of environmental conditions including their respective projections from the domestication center to the area of origin and vice versa. We used eight variables of temperature and precipitation. Additionally, we included tomato records from bibliographical sources and fieldwork. We also used the niche comparison test (equivalency and similarity) proposed by Broennimann et al. (2012) to evaluate the similarity of environmental conditions in both regions. Subsequently, we carried out an analysis of variance followed by a mean comparison test (Tukey, P ≤ 0.05) with all environmental variables measured. The values of AUC (0.93 and 0.80) and partial-ROC (1.86 and 1.71, P = 0.0001) of the MNE showed that they were good predictive models. We observed that, in the center of Mexico, there are environmental conditions similar to those of the center of origin, unlike the slope of the Gulf of Mexico where they are different. The equivalency test showed that the environmental comparison between both regions is less similar than expected by chance (P = 0.003). The similarity test indicated that the existing similarity between both regions can also be obtained by chance (P = 0.683). We also found significant differences in three temperature and precipitation variables. In conclusion, we determined that the center of origin and domestication of S. l. var. cerasiforme has similar environmental characteristics despite the geographic distance; nevertheless, there are geographical zones (the Gulf of Mexico in Veracruz) in the area of domestication with different environmental conditions. Those places have the potential to contain valuable germplasms.

Eficacia y tolerabilidad de la reducción del volumen de polietilenglicol para la preparación para colonoscopia / Effectiveness and tolerability of low volume bowel cleansing polyethylene glycol solution for colonoscopy

Background: A successful colonoscopy depends, among other factors, on a proper colon cleansing. This variable also affects the acceptance of the patient to carry out the study. Aim: To analyze the efficacy and tolerability of a low volume polyethylene glycol formulation (2 liters), compared to the conventional presentation of 4 liters. Material and Methods: Patients referred for a colonoscopy were randomly divided to receive either two or four liter of polyethylene glycol as bowel cleansing, which was assessed using the Boston score. Raters of the latter were blinded to the volume of polyethylene glycol that the patients used. Results: Seventy-four patients participated in the study. Subjects who received a 4 liters preparation had an average Boston score of 7.78, versus 8.16 for patients who received a volume of 2 liters (p = 0.267). No significant differences in tolerability were observed between both groups. No significant differences in the efficacy and tolerability between a conventional or a reduced volume of polyethylene glycol solution for the preparation of a colonoscopy were observed. These findings may be especially important for subgroups of patients with difficulties for oral administration of fluids.

Museum genomics reveals the speciation history of Dendrortyx wood-partridges in the Mesoamerican highlands.

Natural history collections are increasingly valued as genomic resources. Their specimens reflect the combined efforts of collectors and curators over hundreds of years. For many rare or endangered species, specimens are the only readily available source of DNA. We leveraged specimens from a historical collection to study the evolutionary history of wood-partridges in the genus Dendrortyx. The three Dendrortyx species are found in the highlands of central Mexico and Central America south to Costa Rica. One of these species is endangered, and in general, Dendrortyx are secretive and poorly represented in tissue collections. We extracted DNA from historical museum specimens and sequenced ultraconserved elements (UCEs) and mitochondrial DNA (mtDNA) to assess their phylogeny and divergence times. Phylogenies built from hundreds to thousands of nuclear markers were well resolved and largely congruent with an mtDNA phylogeny. The divergence times revealed an unusually old avian divergence across the Isthmus of Tehuantepec in the Pliocene around 3.6 million years ago. Combined with other recent studies, our results challenge the general pattern that highland bird divergences in Mesoamerica are relatively young and influenced by the Pleistocene glacial cycles compared to the older divergences of reptiles and plants, which are thought to overlap more with periods of mountain formation. We also found evidence for monophyletic genetic lineages in mountain ranges within the widespread D. macroura, which should be investigated further with integrative taxonomic methods. Our study demonstrates the power of museum genomics to provide insight into the evolutionary histories of groups where modern samples are lacking.