Chemotaxis When Bacteria Remember: Drift versus Diffusion

{\sl Escherichia coli} ({\sl E. coli}) bacteria govern their trajectories by switching between running and tumbling modes as a function of the nutrient concentration they experienced in the past. At short time one observes a drift of the bacterial population, while at long time one observes accumulation in high-nutrient regions. Recent work has viewed chemotaxis as a compromise between drift toward favorable regions and accumulation in favorable regions. A number of earlier studies assume that a bacterium resets its memory at tumbles -- a fact not borne out by experiment -- and make use of approximate coarse-grained descriptions. Here, we revisit the problem of chemotaxis without resorting to any memory resets. We find that when bacteria respond to the environment in a non-adaptive manner, chemotaxis is generally dominated by diffusion, whereas when bacteria respond in an adaptive manner, chemotaxis is dominated by a bias in the motion. In the adaptive case, favorable drift occurs together with favorable accumulation. We derive our results from detailed simulations and a variety of analytical arguments. In particular, we introduce a new coarse-grained description of chemotaxis as biased diffusion, and we discuss the way it departs from older coarse-grained descriptions.Comment: Revised version, journal reference adde

Effects of a brief mindfulness-based intervention on emotional regulation and levels of mindfulness in senior students

Mindfulness-based interventions have been applied in diverse populations and achieved mental health benefits. This study examined the effects of a brief mindfulness program for emotional regulation and levels of mindfulness on senior students in Brazil. The intervention consisted of six weekly meetings attended by 30 participants. It is a pre-experimental research, with pre- and post-test comparative and correlation measurements. The preliminary results, which relied on parametrical and non-parametrical tests, revealed a reduction in total emotional regulation difficulties (p = 0.0001; r = − 0.55). Also, there was an increase in the levels of mindfulness in the subtests for both dimensions under evaluation: “Awareness” (p = 0.0001; d = 0.77) and “Acceptance” (p = 0.048; d = 0.37). By associating the amount of meditative practices performed by students with the variables, a significant positive correlation was found with the mindfulness dimension “Awareness” (rP = 0.422; p = 0.020), and there was a significant negative correlation with Difficulties in emotion regulation (rS = − 0.478; p = 0.008) and with its respective subscales “Non-acceptance” (rS = − 0.654; p = 0.0001) and “Clarity” (rS = − 0.463; p = 0.010). In conclusion, the application of a brief mindfulness-based intervention is promising in Brazilian university contexts; moreover, it can bring benefits to students, e.g., an increase in emotion regulation as well as in levels of mindfulness. We suggest that further research should use an experimental design and follow-up.info:eu-repo/semantics/publishedVersio

Depression among women living in the outskirts of São Paulo, Southeastern Brasil

OBJECTIVE: To assess the meaning of depression in women diagnosed with the disorder, and the context of care given by the psychiatrists who follow them up. METHODS: Qualitative study performed in Embu, outskirt of São Paulo, between August 2002 and January 2003. Etnographic observation and in-depth interview were carried out with 16 women diagnosed with depression in primary care, and four psychiatrists. After exhaustive reading, data were grouped into categories and assessed. The assessment of outcomes was based on the concept of culture. RESULTS: Women interviewed are well aware of the disorder, and accept treatment based on medication. For psychiatrists, depression is a term understood by the common sense. All women interviewed identified the onset of the disease from a past event such as: death of a son, violent episodes connected with drug traffic, unemployment, and partners' aggressiveness. Violence was common in the every day life of the interviewed women both inside and outside their homes. CONCLUSIONS: For these women, depression is a way to express their feelings, such as unhappiness in a context of poverty and violence. Psychiatrists go beyond their clinical functions and play an important role on reorganizing the daily life of these women.OBJETIVO: Analisar o significado da depressão para mulheres diagnosticadas com o transtorno e o contexto do atendimento realizado pelos psiquiatras que as acompanham. MÉTODOS: Estudo qualitativo realizado no município de Embu, na Grande São Paulo, entre agosto de 2002 e janeiro de 2003. Foram realizadas observação etnográfica e entrevistas em profundidade com 16 mulheres diagnosticadas com depressão, pacientes de uma Unidade Básica de Saúde, e quatro psiquiatras. Após a leitura exaustiva, os dados foram agrupados em categorias e analisados. A interpretação dos resultados baseou-se no conceito de cultura. RESULTADOS: As entrevistadas tinham ampla noção do transtorno, aceitando o tratamento com medicação. Para os psiquiatras, a depressão é um termo assimilado pelo senso-comum. Todas as entrevistadas identificaram a origem da doença em eventos passados, como: morte de filho, episódios violentos ligados ao tráfico de drogas, desemprego e agressividade do companheiro. A violência era comum no cotidiano das entrevistadas, tanto fora como dentro de casa. CONCLUSÕES: Para essas mulheres, a depressão era uma forma de expressar sentimentos, como a infelicidade num contexto de pobreza e violência. Os psiquiatras extrapolam as suas funções clínicas e têm um papel na reorganização do cotidiano dessas mulheres.Universidade Católica de Santos Programa de Mestrado em Saúde ColetivaUniversidade Federal de São Paulo (UNIFESP) Departamento de PsiquiatriaUNIFESP, Depto. de PsiquiatriaSciEL

Promoção, prevenção e cuidado da hipertensão arterial no Brasil

OBJETIVO: Estimar a prevalência de ações de promoção, prevenção e cuidado da hipertensão arterial em adultos e identificar sua associação com estado descompensado de hipertensão. MÉTODOS: Estudo epidemiológico transversal de base populacional realizado por meio de entrevista com 12.324 adultos, de 20 a 59 anos, em 100 municípios brasileiros. As variáveis independentes, consideradas como promoção, prevenção e cuidado, foram: ter recebido orientações sobre a manutenção do peso ideal e sobre atividade física; ter consultado um médico e ter realizado eletrocardiograma no último ano. Pressão arterial acima de 140/90 mmHg foi considerada estado descompensado, sendo a variável dependente para a avaliação da qualidade do cuidado. RESULTADOS: Do total, 16,3% (n = 2.004) referiram diagnóstico médico de hipertensão. As maiores prevalências de hipertensão foram observadas na categoria de idade de 50 a 59 anos, concentradas nas regiões Sudeste e Centro-Oeste. Mais da metade (66,1%) esteve em consulta médica por hipertensão no último ano, da qual metade (52,4%) realizou eletrocardiograma. Dos hipertensos que tiveram sua pressão arterial aferida na entrevista (74,6%), menos da metade (42,4%) apresentava cifras tensionais descompensadas. CONCLUSÕES: Não houve associação entre haver consultado médico no último ano e cifras tensionais descompensadas. A proporção de hipertensos descompensados foi significativamente menor entre os que foram orientados para manter o peso ideal, realizar atividade física e os que fizeram eletrocardiograma. Ser do sexo masculino, ter idade acima de 40 anos e habitar na região Sul mostraram-se associados a estado descompensado da hipertensão.OBJECTIVE: To estimate the prevalence of promotion, prevention and arterial hypertension care actions in adults and to identify their association with decompensated hypertension. METHODS: A population-based cross-sectional epidemiological study was conducted by interviewing 12,324 adults aged from 20 to 59 years, in 100 Brazilian cities. The independent variables considered as promotion, prevention and hypertension care were as follows: to have received guidance on ideal weight maintenance and physical activity practice; to have consulted a doctor; and to have had an electrocardiogram performed in the previous year. A blood pressure higher than 140/90 mm/Hg was considered to be decompensated, being the dependent variable adopted to assess quality of care. RESULTS: Of all participants, 16.3% (n = 2,004) reported a medical diagnosis of hypertension. The highest prevalences of hypertension were observed in the 50 to 59 year age group, primarily in the Southeast and Center-West regions. More than half (66.1%) of participants had a medical consultation about hypertension in the previous year, of which half (52.4%) had an electrocardiogram. Of all those with hypertension who had their blood pressure measured during interview (74.6%), less than half (42.4%) had decompensated values. CONCLUSIONS: There was no association between having consulted a doctor in the previous year and decompensated blood pressure values. The proportion of decompensated hypertensive participants was significantly lower among those who had received guidance on ideal weight maintenance and physical activity practice and those who had had an electrocardiogram performed. The following factors were associated with decompensated hypertension: to be male, to be aged more than 40 years and to live in the South region.OBJETIVO: Estimar la prevalencia de acciones de promoción, prevención y cuidado de la hipertensión arterial en adultos e identificar la asociación con el estado descompensado de hipertensión. MÉTODOS: Estudio epidemiológico transversal de base poblacional realizado a través de entrevista en 12.324 adultos, de 20 a 59 años, en 100 municipios brasileños. Las variables independientes, consideradas como promoción, prevención y cuidado fueron: haber recibido orientaciones sobre la manutención del peso ideal y actividad física; haber consultado un médico y haber realizado el electrocardiograma en el último año. Presión arterial por encima de 140/90 mm/Hg se consideró estado descompensado, siendo la variable dependiente para la evaluación de la calidad del cuidado. RESULTADOS: del total, 16,3% (n= 2.004) refirieron diagnóstico médico de hipertensión. Las mayores prevalencias de hipertensión se observaron en la categoría de edad de 50 a 59 años, concentradas en las regiones Sureste y Centro-Oeste. Más de la mitad (66,1%) estuvo en consulta médica por hipertensión en el último año, y la mitad de estos (52,4%) realizó electrocardiograma. De los hipertensos que chequearon la presión arterial en la entrevista, 74,6%, menos de la mitad (42,4%) presentó cifras tensionales descompensadas. CONCLUSIONES: No hubo asociación entre haber consultado el médico en el último año y cifras tensionales descompensadas. La proporción de hipertensos descompensados fue significativamente menor entre los que fueron orientados para mantener el peso ideal, realizar actividad física y los que hicieron electrocardiograma. Ser del sexo masculino, tener edad por encima de 40 años y habitar en la región Sur, se evidenciaron asociados al estado descompensado de la hipertensión

Lack of HLA predominance and HLA shared epitopes in biliary Atresia

Biliary atresia (BA) is characterized by progressive inflammation and fibrosis of bile ducts. A theory of pathogenesis entails autoimmune-mediated injury targeting bile duct epithelia. One of the strongest genetic associations with autoimmunity is with HLA genes. In addition, apparently dissimilar HLA alleles may have similar antigen-binding sites, called shared epitopes, that overlap in their capacity to present antigens. In autoimmune disease, the incidence of the disease may be related to the presence of shared epitopes, not simply the HLA allelic association. Aim: To determine HLA allele frequency (high-resolution genotyping) and shared epitope associations in BA. Results: Analysis of every allele for HLA-A, -B, -C, -DRB1, -DPB1 and -DQB1 in 180 BA and 360 racially-matched controls did not identify any significant HLA association with BA. Furthermore, shared epitope analysis of greater than 10 million possible combinations of peptide sequences was not different between BA and controls. Conclusions: This study encompasses the largest HLA allele frequency analysis for BA in the United States and is the first study to perform shared epitope analysis. When controlling for multiple comparisons, no HLA allele or shared epitope association was identified in BA. Future studies of genetic links to BA that involve alterations of the immune response should include investigations into defects in regulatory T cells and non-HLA linked autoinflammatory diseases. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/2193-1801-2-42) contains supplementary material, which is available to authorized users

Spinocerebellar ataxia type 17: Report of a family with reduced penetrance of an unstable Gln(49 )TBP allele, haplotype analysis supporting a founder effect for unstable alleles and comparative analysis of SCA17 genotypes

BACKGROUND: Spinocerebellar ataxia type 17 (SCA17), a neurodegenerative disorder in man, is caused by an expanded polymorphic polyglutamine-encoding trinucleotide repeat in the gene for TATA-box binding protein (TBP), a main transcription factor. Observed pathogenic expansions ranged from 43 – 63 glutamine (Gln) codons (Gln(43–63)). Reduced penetrance is known for Gln(43–48 )alleles. In the vast majority of families with SCA17 an expanded CAG repeat interrupted by a CAA CAG CAA element is inherited stably. RESULTS: Here, we report the first pedigree with a Gln(49 )allele that is a) not interrupted, b) unstable upon transmission, and c) associated with reduced penetrance or very late age of onset. The 76-year-old father of two SCA17 patients carries the Gln(49 )TBP allele but presents without obvious neurological symptoms. His children with Gln(53 )and Gln(52 )developed ataxia at the age of 41 and 50. Haplotype analysis of this and a second family both with uninterrupted expanded and unstable pathological SCA17 alleles revealed a common core genotype not present in the interrupted expansion of an unrelated SCA17 patient. Review of the literature did not present instability in SCA17 families with expanded alleles interrupted by the CAA CAG CAA element. CONCLUSION: The presence of a Gln(49 )SCA17 allele in an asymptomatic 76-year-old male reams the discussion of reduced penetrance and genotypes producing very late disease onset. In SCA17, uninterrupted expanded alleles of TBP are associated with repeat instability and a common founder haplotype. This suggests for uninterrupted expanded alleles a mutation mechanism and some clinical genetic features distinct from those alleles interrupted by a CAA CAG CAA element