466 research outputs found
Mid-Infrared diagnostics of metal-rich HII regions from VLT and Spitzer Spectroscopy of Young Massive Stars in W31
We present near-IR VLT/ISAAC and mid-IR Spitzer/IRS spectroscopy of the young
massive cluster in the W31 star-forming region. H-band spectroscopy provides
refined classifications for four cluster members O stars with respect to Blum
et al. In addition, photospheric features are detected in the massive Young
Stellar Object (mYSO) #26. Spectroscopy permits estimates of stellar
temperatures and masses, from which a cluster age of ~0.6 Myr and distance of
3.3 kpc are obtained, in excellent agreement with Blum et al. IRS spectroscopy
reveals mid-infrared fine structure line fluxes of [Ne II-III] and [S III-IV]
for four O stars and five mYSOs. In common with previous studies, stellar
temperatures of individual stars are severely underestimated from the observed
ratios of fine-structure lines, despite the use of contemporary stellar
atmosphere and photoionization models. We construct empirical temperature
calibrations based upon the W31 cluster stars of known spectral type,
supplemented by two inner Milky Way ultracompact (UC) HII regions whose
ionizing star properties are established. Calibrations involving [NeIII]
15.5um/[NeII] 12.8um, [SIV] 10.5um/[NeII] 12.8um or [ArIII] 9.0um/[NeII] 12.8um
have application in deducing the spectral types of early- to mid- O stars for
other inner Milky Way compact and UCHII regions. Finally, evolutionary phases
and timescales for the massive stellar content in W31 are discussed, due to the
presence of numerous young massive stars at different formation phases in a
`coeval' cluster.Comment: 16 pages, 13 figures, accepted for MNRA
MicroRNA-21 dysregulates the expression of MEF2C in neurons in monkey and human SIV/HIV neurological disease
MicroRNAs (miRNAs) have important roles in regulating a plethora of physiological and pathophysiogical processes including neurodegeneration. In both human immunodeficiency virus (HIV)-associated dementia in humans and its monkey model simian immunodeficiency virus encephalitis (SIVE), we find miR-21, a miRNA largely known for its link to oncogenesis, to be significantly upregulated in the brain. In situ hybridization of the diseased brain sections revealed induction of miR-21 in neurons. miR-21 can be induced in neurons by prolonged N-methyl--aspartic acid receptor stimulation, an excitotoxic process active in HIV and other neurodegenerative diseases. Introduction of miR-21 into human neurons leads to pathological functional defects. Furthermore, we show that miR-21 specifically targets the mRNA of myocyte enhancer factor 2C (MEF2C), a transcription factor crucial for neuronal function, and reduces its expression. MEF2C is dramatically downregulated in neurons of HIV-associated dementia patients, as well as monkeys with SIVE. Together, this study elucidates a novel role for miR-21 in the brain, not only as a potential signature of neurological disease, but also as a crucial effector of HIV-induced neuronal dysfunction and neurodegeneration
PESCADOR, a web-based tool to assist text-mining of biointeractions extracted from PubMed queries
BACKGROUND: Biological function is greatly dependent on the interactions of proteins with other proteins and genes. Abstracts from the biomedical literature stored in the NCBI's PubMed database can be used for the derivation of interactions between genes and proteins by identifying the co-occurrences of their terms. Often, the amount of interactions obtained through such an approach is large and may mix processes occurring in different contexts. Current tools do not allow studying these data with a focus on concepts of relevance to a user, for example, interactions related to a disease or to a biological mechanism such as protein aggregation. RESULTS: To help the concept-oriented exploration of such data we developed PESCADOR, a web tool that extracts a network of interactions from a set of PubMed abstracts given by a user, and allows filtering the interaction network according to user-defined concepts. We illustrate its use in exploring protein aggregation in neurodegenerative disease and in the expansion of pathways associated to colon cancer. CONCLUSIONS: PESCADOR is a platform independent web resource available at: http://cbdm.mdc-berlin.de/tools/pescador
Factors affecting compliance with the measles vaccination schedule in a Brazilian city
CONTEXT AND OBJECTIVE: The success of vaccination campaigns depends on the degree of adherence to immunization initiatives and schedules. Risk factors associated with children's failure to receive the measles vaccine at the correct age were studied in the city of SĂŁo Paulo, Brazil. DESIGN AND SETTING: Case-control and exploratory study, in the metropolitan area of SĂŁo Paulo. METHODS: The caregivers of 122 children were interviewed regarding their perceptions and understanding about the measles vaccination and the disease. RESULTS: The results showed that age, region of residence, marital status and education level were unrelated to taking measles vaccines adequately. Most individuals remembered being informed about the last annual vaccination campaign by television, but no communication channel was significantly associated with vaccination status. The answers to questions about knowledge of the disease or the vaccine, when analyzed alone, were not associated with taking measles vaccinations at the time indicated by health agencies. The results showed that, when parents felt sorry for their children who were going to receive shots, they delayed the vaccination. Most of the children did not take the measles vaccination on the exactly recommended date, but delayed or anticipated the shots. CONCLUSION: It is clear that there is no compliance with the government's recommended measles vaccination schedule (i.e. first dose at nine and second at 15 months of age, as recommended in 1999 and 2000). Feeling sorry for the children receiving shots can delay vaccination taking
Sodium channel slow inactivation interferes with open channel block
Mutations in the voltage-gated sodium channel Nav1.7 are linked to inherited pain syndromes such as erythromelalgia (IEM) and paroxysmal extreme pain disorder (PEPD). PEPD mutations impair Nav1.7 fast inactivation and increase persistent currents. PEPD mutations also increase resurgent currents, which involve the voltage-dependent release of an open channel blocker. In contrast, IEM mutations, whenever tested, leave resurgent currents unchanged. Accordingly, the IEM deletion mutation L955 (ÎL955) fails to produce resurgent currents despite enhanced persistent currents, which have hitherto been considered a prerequisite for resurgent currents. Additionally, ÎL955 exhibits a prominent enhancement of slow inactivation (SI). We introduced mutations into Nav1.7 and Nav1.6 that either enhance or impair SI in order to investigate their effects on resurgent currents. Our results show that enhanced SI is accompanied by impaired resurgent currents, which suggests that SI may interfere with open-channel block
Relacao entre o nivel de atividade fisica estimado pelo Baltimore Activity Scale for Intermittent Claudication e a pedometria em pacientes com claudicacao intermitente
CONTEXTO: Os pacientes com claudicação intermitente apresentam nĂveis reduzidos de atividade fĂsica. A Baltimore Activity Scale for Intermittent Claudication (BASIC) foi validada para quantificar o nĂvel de atividade fĂsica destes pacientes. No entanto, esta validação se baseou em apenas dois dias de monitoramento com acelerĂŽmetros, de modo que ainda permanece incerto se a BASIC fornece informaçÔes sobre os nĂveis de atividade fĂsica semanal. OBJETIVO: Analisar a correlação entre o nĂvel de atividade fĂsica estimada pela BASIC e o nĂvel obtido pelo pedĂŽmetro em uma semana, em pacientes com claudicação intermitente. MĂTODOS: Foram estudados 150 pacientes com claudicação intermitente, com idade entre 30 e 80 anos. Foram obtidos os dados sociodemogrĂĄficos e verificada a presença de comorbidades e de fatores de risco cardiovascular, e a BASIC. O pedĂŽmetro foi utilizado por sete dias consecutivos, sendo a anĂĄlise feita em trĂȘs diferentes perĂodos de monitorização (todos os dias, dias da semana e do fim de semana). RESULTADOS: Foi observada correlação entre a BASIC e a mĂ©dia de passos de todos os dias (rho=0,343; p<0,001), dos dias de semana (rho=0,336; p<0,001) e dos dias do final de semana (rho=0,317; p<0,001). CONCLUSĂO: Em pacientes com claudicação intermitente, o nĂvel de atividade fĂsica estimado pela BASIC se correlaciona com o nĂvel de atividade fĂsica semanal
- âŠ