RESUMO
Bacterial biofilms are important in natural settings, biotechnology, and medicine. However, regulation of biofilm development and its persistence in different niches is complex and only partially understood. One key step during the biofilm life cycle is dispersal, when motile cells abandon the mature biofilm to spread out and colonize new niches. Here, we show that in the model bacterium Bacillus subtilis the general stress transcription factor SigB is essential for halting detrimental overgrowth of mature biofilm and for triggering dispersal when nutrients become limited. Specifically, SigB-deficient biofilms were larger than wild-type biofilms but exhibited accelerated cell death, significantly greater sensitivity to different stresses, and reduced dispersal. Interestingly, the signal detected by SigB to limit biofilm growth was transduced through the RsbP-dependent metabolic arm of the SigB regulatory cascade, which in turn positively controlled expression of SinR, the master regulator of biofilm formation and cell motility. This novel SigB-SinR regulatory circuit might be important in controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.IMPORTANCE Biofilms are crucial for bacterial survival, adaptation, and dissemination in natural, industrial, and medical systems. Sessile cells embedded in the self-produced extracellular matrix of the biofilm benefit from a division of labor and are protected from environmental insults. However, as the biofilm ages, cells become stressed because of overcrowding, starvation, and accumulation of waste products. How does the sessile biofilm community sense and respond to stressful conditions? Here, we show that in Bacillus subtilis, the transcription factors SigB and SinR control whether cells remain in or leave a biofilm when metabolic conditions become unfavorable. This novel SigB-SinR regulatory circuit might be important for controlling the fitness of biofilms (either beneficial or harmful) in diverse environments.
Assuntos
Bacillus subtilis/crescimento & desenvolvimento , Proteínas de Bactérias/metabolismo , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Fator sigma/metabolismo , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Meios de Cultura/química , Locomoção , Metabolismo , Fator sigma/deficiênciaRESUMO
INTRODUCTION: The attitude of medical students towards homosexuality may affect the quality of care for homosexual patients. This study aimed to describe the attitude of medical students at the National University of Asuncion, Paraguay towards homosexuality. METHODS: This observational, cross-sectional study was conducted in June 2016 in consecutive medical students from the National University of Asunción (Santa Rosa del Aguaray branch), Paraguay. The 10-item attitude towards homosexuality scale (EAH-10) was used to assess participants' acceptance/ rejection of homosexuals as individuals, homosexuality as a sexual orientation, and public manifestations of homosexuality. RESULTS: A total of 48 female and 29 male participants (mean age, 21 ± 2 years) were included. Most were Catholic (71.4%), followed by non-Catholic Christian (10.4%), agnostic (9.1%), atheist (2.6%), and other (6.5%). 71.4% reported having at least one homosexual friend. The mean EAH-10 score was 27.23 ± 9.379. 42.9% of participants were indifferent or undecided in their attitude towards homosexuality and 28.6% were discriminatory. Having homosexual friends was associated with a lower EAH-10 score (t = -3.447 [75], p = 0.001). CONCLUSION: Education about health issues of homosexuals is needed for medical students in Paraguay.
Assuntos
Atitude do Pessoal de Saúde , Homossexualidade/psicologia , Estudantes de Medicina/psicologia , Estudos Transversais , Feminino , Humanos , Masculino , Paraguai , Adulto JovemRESUMO
El término Enfermedad Inflamatoria Intestinal (EII) incluye a un grupo de entidades clínicas que se caracterizan por ser procesos inflamatorios crónicos de etiología desconocida, y afectar primordialmente, aunque no de forma exclusiva, al intestino. Actualmente se reconocen varias entidades que se engloban en este concepto: Colitis Ulcerosa (CU), Enfermedad de Crohn (EC), Colitis Inclasificada (CI), Colitis Microscópica (CM) y Reservoritis (Pouchitis). La Enfermedad de Crohn puede afectar a cualquier tramo del intestino, siendo la localización más frecuente la Ileal y Colónica en forma simultánea. El proceso inflamatorio en la EC es transmural y sus síntomas fundamentales son la diarrea generalmente crónica y/o el dolor abdominal. Presentamos el caso de una mujer joven con una EC que compromete exclusivamente al ileon terminal, en la que se realizó el diagnóstico de EC ileal por la clínica, la endoscopía y la anatomía patológica, que respondió satisfactoriamente a la terapéutica instaurada, y se revisa el concepto de la EC con énfasis en su diagnóstico.
The term Inflammatory Bowel Disease (IBD) includes a group of clinical entities that are characterized by chronic inflammatory processes of unknown etiology, and primarily, but not exclusively, affecting the intestine. Currently, several entities are included in this concept: Ulcerative Colitis (UC), Crohn's Disease (CD), Unclassified Colitis (UC), Microscopic Colitis (CM) and Reservoritis (Pouchitis). Crohn's Disease can affect any part of the intestine, with the most frequent location being ileal and colonic simultaneously. The inflammatory process in CD is transmural and its fundamental symptoms are usually chronic diarrhea and/or abdominal pain. We present the case of a young woman with a CD that exclusively compromises the terminal Ileon, in whom the diagnosis of ileal CD was performed with the clinical data, the endoscopic procedure and the pathological study, who responded satisfactorily to the established therapy, and the concept of CD with an emphasis on its diagnosis is reviewed.
Assuntos
Humanos , Feminino , Adulto , Doença de Crohn/diagnóstico , Ileíte/diagnóstico , Doença de Crohn/tratamento farmacológico , Ileíte/tratamento farmacológico , Íleo/patologiaRESUMO
Past positive experiences can increase herbivores' motivation to eat low-quality foods. However, this is not always translated into a higher preference for low-quality foods in choice tests among foods of higher nutritional quality. Foraging behavior is also affected by properties of the feeding context because the quality and abundance of foods in nature change in time and space. We hypothesized that in a choice situation, the expression of a past positive experience with a low-quality food is modulated by the costs associated with selecting a high-quality food option. A total of 24 sheep were randomly assigned into two groups (n=12). During conditioning phase, one group (CS+; i.e., conditioned group) was fed with oat hay (a low-quality food) for 20 min and immediately after a ration of soybean meal (a nutritious food), whereas the other group was also fed with oat hay but the offer of soybean meal was delayed 5 h (CS-; i.e., control group). After conditioning, we assessed sheep motivation to eat the oat hay in an experimental arena in which accessibility to alfalfa hay (a high-quality food) was increasingly restricted. When alfalfa hay was readily accessible, CS+ and CS- sheep almost exclusively selected this food, showing a small and similar preference for oat hay. However, when accessibility to alfalfa hay decreased, intake and selection of oat hay was greater in the CS+ sheep than in the CS- sheep. The latter was a consequence of differential changes in behavior between groups; for example, sheep in CS+ spent more time foraging oat hay and were more likely to switch to oat hay if they had previously been eating alfalfa hay than sheep in CS-. Our results show that behavioral expression of the conditioned preference for a low-quality food depends on parameters of the feeding context (e.g., availability). We suggest that this can be the link between learning models and optimal foraging models of diet selection.
Assuntos
Comportamento de Escolha , Metabolismo Energético , Preferências Alimentares , Carneiro Doméstico/fisiologia , Ração Animal/análise , Animais , Condicionamento Operante , Dieta/veterinária , Valor NutritivoRESUMO
Tannins in sainfoin (Onobrychis viciifolia) may bind to alkaloids in endophyte-infected tall fescue [E+; Lolium arundinaceum (Schreb.) Darbysh.] and attenuate toxicosis. If so, supplementing E+ with sainfoin will increase use of E+ by sheep, and polyethylene glycol (PEG)-a polymer that selectively binds to tannins-will reduce such response. To test these predictions, thirty-six 2-mo-old lambs were randomly assigned to 3 treatments (12 lambs/treatment). During exposure, all lambs were individually penned and fed E+ supplemented with beet pulp (CTRL), fresh-cut sainfoin and beet pulp (SAIN), or fresh-cut sainfoin plus PEG mixed in beet pulp (SAIN+PEG). Feed intake was measured daily. Rectal temperatures and jugular blood samples were taken at the beginning and end of exposure. After exposure, all lambs were offered choices between endophyte-free tall fescue (E-) and orchardgrass, and preference for E- was assessed. Then, all lambs were allowed to graze a choice of E+ and sainfoin or a monoculture of E+. The foraging behavior of lambs was recorded. When sainfoin was in mid-vegetative stage, lambs in SAIN ingested more E+ than lambs in CTRL (P = 0.05), but no differences were detected between lambs in SAIN+PEG and CTRL (P = 0.12). Sainfoin supplementation improved some physiological parameters indicative of fescue toxicosis. Lambs in SAIN had lower rectal temperatures (P = 0.02), greater numbers of leukocytes (P < 0.001) and lymphocytes (P = 0.03), and greater plasmatic concentrations of globulin (P = 0.009) and prolactin (P = 0.019) than lambs in CTRL. Some of these differences were offset by the SAIN+PEG treatment. When lambs were offered choices between E- and orchardgrass, only lambs in SAIN had greater intake of E- than lambs in CTRL (P < 0.001). When lambs were allowed to graze a choice of E+ and sainfoin, all treatments used E+ to the same extent (P > 0.05). On the other hand, when they grazed on a monoculture of E+, lambs in SAIN+PEG showed greater acceptance of E+ than lambs in SAIN or in CTRL (P < 0.05). In summary, sainfoin supplementation alleviated several of the classic signs of fescue toxicosis and increased intake of endophyte-infected tall fescue. Tannins in sainfoin partially accounted for this benefit since feeding a polymer that selectively binds to tannins (PEG) attenuated some these responses. However, sainfoin supplementation during initial exposure to E+ did not lead to an increased preference for E+ during grazing.
Assuntos
Ração Animal/microbiologia , Suplementos Nutricionais , Endófitos/química , Poaceae/química , Poaceae/microbiologia , Polietilenoglicóis/farmacologia , Ração Animal/análise , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Ergotaminas/toxicidade , Contaminação de Alimentos , OvinosRESUMO
The immune regulatory mechanisms involved in the acquisition of Mycobacterium tuberculosis infection in children are largely unknown. We investigated the influence of parasitic infections, malnutrition and plasma cytokine profiles on tuberculin skin test (TST) positivity in Warao Amerindians in Venezuela. Pediatric household contacts of sputum smear-positive tuberculosis (TB) cases were enrolled for TST, chest radiograph, plasma cytokine analyses, QuantiFERON-TB Gold In-Tube (QFT-GIT) testing and stool examinations. Factors associated with TST positivity were studied using generalized estimation equations logistic regression models. Of the 141 asymptomatic contacts, 39% was TST-positive. After adjusting for age, gender and nutritional status, TST positivity was associated with Trichuris trichiura infections (OR 3.5, 95% CI 1.1-11.6) and low circulating levels of T helper 1 (Th1) cytokines (OR 0.51, 95% CI 0.33-0.79). Ascaris lumbricoides infections in interaction with Th2- and interleukin (IL)-10-dominated cytokine profiles were positively associated with TST positivity (OR 3.1, 95% CI 1.1-8.9 and OR 2.4, 95% CI 1.04-5.7, respectively). A negative correlation of QFT-GIT mitogen responses with Th1 and Th2 levels and a positive correlation with age were observed (all p < 0.01). We conclude that helminth infections and low Th1 cytokine plasma levels are significantly associated with TST positivity in indigenous Venezuelan pediatric TB contacts.
Assuntos
Citocinas/imunologia , Helmintíase/imunologia , Desnutrição/imunologia , Mycobacterium tuberculosis/imunologia , Grupos Populacionais , Teste Tuberculínico , Tuberculose/imunologia , Animais , Ascaris lumbricoides/isolamento & purificação , Criança , Pré-Escolar , Estudos Transversais , Características da Família , Feminino , Helmintíase/diagnóstico , Helmintíase/epidemiologia , Humanos , Modelos Logísticos , Masculino , Desnutrição/diagnóstico , Desnutrição/epidemiologia , Prevalência , Kit de Reagentes para Diagnóstico , Fatores de Risco , Trichuris/isolamento & purificação , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Venezuela/epidemiologiaRESUMO
This study determined whether early experiences by sheep with monotonous or diverse diets influence intake of unfamiliar flavors and feeds later in life. Thirty 2-mo-old lambs were randomly assigned to 3 treatment diets (n = 10): diverse (DIV), diverse with plant toxins (DIV+T), and monotonous (MON). Lambs in DIV received in 9 successive periods of exposure 4-way choice combinations of 2 foods high in energy and 2 foods high in protein from an array of 6 foods: 3 high in energy [beet pulp, oat grain, and a mix of milo:grape pomace (60:40)] and 3 high in digestible protein (DP) (soybean meal, alfalfa, corn gluten meal). Lambs in DIV+T received the same exposure as DIV, but 2 plant toxins, oxalic acid (1.5%) and quebracho tannins (10%), were randomly added to 2 of the feeds in each of the choice combinations. Lambs in MON received a monotonous balanced diet, made with a mixture of all 6 feeds detailed before. All treatments received their feed in 4 separate buckets. During exposure, treatments did not differ in total daily DMI (P = 0.31), but daily intake of ME was less (P < 0.02) and daily intake of DP was greater (P < 0.03) for lambs in DIV and DIV+T than for lambs in MON. Treatments did not differ in ADG or G:F (P > 0.05). After exposure, lambs were offered a familiar feed (wheat bran) containing novel flavors (maple, garlic, or bitter) and 2-way choices of novel feeds (fescue hay vs. corn distillers grains, rice vs. calf manna, and green peas vs. rolled oats). Intake of maple-flavored wheat bran tended (P = 0.08) to be greater for lambs in DIV than for lambs in DIV+T and MON. Intake of bitter-flavored and garlic-flavored wheat bran were greater (P = 0.03 and P = 0.04, respectively) for lambs in DIV and DIV+T than for lambs in MON. During 2-way choice trials, lambs in DIV, but not in DIV+T, showed greater intakes of fescue hay (P = 0.05) and rice (P = 0.04) than lambs in MON. Intake of green peas was greater (P = 0.03) for lambs in DIV and DIV+T than for lambs in MON. At the end of testing, lambs in DIV but not in DIV+T showed greater ADG than lambs in MON (P = 0.05). Thus, early exposure to diverse foods enhanced acceptance of novel flavors relative to early exposure to a monotonous ration. Early experience with diverse feeds plus plant toxins led to a less diverse diet than early experience with diverse feeds. Early exposure to diverse feeds may be beneficial in production systems that require rapid acceptance and high intake of unfamiliar feeds.
Assuntos
Ração Animal/análise , Comportamento Exploratório/fisiologia , Comportamento Alimentar/fisiologia , Ovinos , Ração Animal/classificação , Fenômenos Fisiológicos da Nutrição Animal , Animais , Dieta/veterinária , Ingestão de Alimentos , Feminino , Preferências Alimentares/fisiologia , MasculinoRESUMO
Objetivo: Describir el uso de Ventilación No Invasiva (VNI) en pacientes internados en una Unidad de Cuidados Intensivos (UCI) cardiovascular (CCV) pediátrica e identificar factores de riesgo que lleven al fracaso, definido como requerimiento de ARM a las 72 hs. Diseño: Estudio observacional analítico, de cohorte retrospectiva. Material y Método: Se estudiaron 340 niños internados en UCI 35 del Hospital Garrahan durante el período 2005-2008 con indicación de VNI por insuficiencia cardiaca (IC), como rescate en el fallo post-extubación y como destete de ARM: se registraron datos demográficos, período pre (PREQ) o postquirúrgico (POP), tipo de interfase, la presencia de atelectasias (ATL), paresia diafragmática (PD), hipertensión pulmonar (HTP), infecciones, defecto residual quirúrgico (DR), lesiones cutáneas (LC), disfunción ventricular (DV), síndromes genéticos (SG), y obstrucción de vías aéreas superiores (VAS), tiempo de exposición a la VNI y fracaso de la VNI. Se utilizó fuente de datos primarios, las variables continuas fueron tratadas con Test de Student o Wilcoxon de acuerdo a su distribución, las variables categóricas con Chi2, se realizó análisis de regresión logística univariado (ARLU) con Wald Test y para el control simultáneo de confundidores, análisis de regresión logística multivariado (ARLM). En todos los casos se tomó como punto de corte 0,05 para asociación estadísticamente significativa (AES). Resultados: Se estudiaron 182 niñas y 158 varones, edad mediana 4,2 meses (r 0,5-216), peso mediana 4,7 kilos(r 2- 64). En el período prequirúrgico (PREQ) 20 y 320 en post quirúrgico(POP). La indicación más frecuente: destete en un 86,76%, la interfase más utilizada fue la cánula nasal (CN) 99,71%, el tiempo de VNI fue de 1 a 11 días con una mediana de 2 días. Se presentaron lesiones cutáneas en un 5,29% y se consideró fracaso en un 17,65%. En el modelo de regresión logística multivariado (MRLM), fueron identificadas como factores de riesgo de fracaso: ATL OR: 2,99 (IC 95%1,23-7,25); edad<=6meses OR: 3,50 (IC95% 1,59-7,73); infecciones OR: 6,93 (IC95% 1,77-27,14); DV, OR: 10,88 (IC 95% 4,44-26,68); el tener obstrucción de VAS OR: 11,66 (IC 95% 4,47-26,68) Conclusiones: Los factores de riesgo que explicaron el fracaso de la VNI en el MRLM fueron la presencia de atelectasia, la edad menor o igual a seis meses, las comorbilidades infecciosas, así como la disfunción ventricular y la obstrucción de VAS. Si bien faltan aún estudios controlados en pediatría, la consideramos una alternativa terapéutica de soporte respiratorio útil y en expansión tanto en el periodo pre como en el post quirúrgico de CCV pediátrica y neonatal (AU)
Objective: To assess the use of non-invasive ventilation (NIV) in patients in the pediatric cardiovascular intensive care unit (ICU) and to identify risk factors that lead to failure, defined as need for mechanical respiratory assistance within 72 hours. Study design: An observational analytical retrospective cohort study. Material and Methods: We studied 340 children with heart failure hospitalized in the ICU 35 of the Garrahan Hospital between 2005 and 2008 who needed NIV as rescue therapy for post-extubation failure and weaning from mechanical respiration. Demographic data, pre- or postsurgical period, type of interface, presence of atelectasis, diaphragmatic paresis, pulmonary hypertension, infections, residual defect, skin lesions, ventricular dysfunction, genetic syndromes, and upper respiratory tract obstruction, time of NIV exposure and NIV failure were recorded. A primary data source was used. According to their distribution, the continuous variables were analyzed uzing the Student's t test or the Wilcoxon test and for categorical variables the Chi-square test was used. Univariate logistic regression analysis was performed using the Wald Test and multivariate logistic regression analysis was done to simultaneously control for confounding factors. In all cases, p< 0.05 was considered as statistically significant. Results: 182 girls and 158 boys with a mean age of 4.2 months (r 0.5-216) and a mean weight of 4.7 kg (r 2- 64) were studied. The period was presurgical in 10 and postsurgical in 320. The most frequent indication was weaning (86.76%), the most-frequently used interface was a nasal tube (99.71%), and time on NIV was between 1 and 11 days with a median of 2 days. Skin lesion were observed in 5.29% and NIV was considered a failure in 17.65%. In the model of multivariate logistic regression the following risk factors were identified: atelectasis, OR: 2.99 (95% CI 1.23-7.25); age ≤ 6 months OR: 3.50 (95% CI 1.59- 7.73); infections, OR: 6.93 (95% CI 1.77-27.14); ventricular dysfunction, OR: 10.88 (95% CI 4.44-26.68); upper respiratory tract obstruction, OR: 11,66 (95% CI 4.47-26.68). Conclusions: Risk factors for NIV failure found with the multivariate logistic regression model were the presence of atelectasis, age ≤ 6 months, infectious comorbidities, as well as ventricular dysfunction and upper respiratory tract obstruction. Although controlled trials are lacking in the pediatric population, we consider NIV to be a useful therapeutic alternative for respiratory support both pre- and postsurgically in pediatric and neonatal cardiovascular disease (AU)
Assuntos
Humanos , Lactente , Unidades de Terapia Intensiva Pediátrica/estatística & dados numéricos , Desmame do Respirador/métodos , Fatores de Risco , Extubação/efeitos adversos , Extubação/métodos , Ventilação não Invasiva/efeitos adversos , Ventilação não Invasiva/estatística & dados numéricos , Cardiopatias Congênitas/cirurgia , Respiração Artificial/métodos , Estudos Retrospectivos , Estudos de Coortes , Modalidades de Fisioterapia , Assistência Perioperatória/métodosRESUMO
Domestic ruminant selectivity induces floristic changes in pasturelands, risking sustainability and limiting the subsequent availability of susceptible plant species. Development of preferences for species of lower nutritional quality may help to overcome those problems. In this study, we tested the hypothesis that early experience of sheep with a low-quality food (LQF) in a nutritional enriched context increases preference for LQF in adulthood. We predicted a higher proportional consumption of LQF in experienced lambs (EL) than in inexperienced lambs (IL) in choice situations involving LQF and alternative foods. Additionally, we determined intake of LQF by EL and IL at different levels of high-quality food (HQF) availability. From 60 to 210 days of age, EL were fed in separated feed bunks mature oat hay (LQF) simultaneously with sunflower meal (SM) and corn grain (CG), whereas IL were fed alfalfa hay (HQF) simultaneously with SM and CG. After exposure, EL and IL were offered LQF in free choice situations involving alternative foods, and also at five levels of HQF availability (100%, 75%, 50%, 25% and 0% of ad libitum intake). Proportional consumption of LQF was lower or similar in EL than IL. Intake of LQF was also lower or similar in EL than IL at all levels of HQF availability, except when the LQF was the only food available. Our results did not support the hypothesis that early experience with a LQF in a nutritional enriched context increases preference for LQF in adulthood. On the contrary, experience with LQF diminished subsequent preference for LQF in adulthood. It is proposed that, in the conditions of our study, continuous comparison between the LQF and the high-quality supplements (CG and SM) during the early exposure period lead to devaluation of LQF by EL through a simultaneous negative contrast effect.