721 research outputs found
Effects of positive airway pressure therapy on cardiovascular and metabolic markers in males with obstructive sleep apnea
Introduction: Obstructive sleep apnea syndrome (OSAS) is associated with cardiovascular/
metabolic complications. Some analytical parameters (homocysteine, glycemic and lipidic
profiles) are recognized markers of these consequences. Limited data is available on the association
of these markers and OSAS’s severity/response to positive airway pressure therapy
(PAP).
Material and methods: In this prospective study we analyzed polysomnographic and analytical
data of male patients admitted to sleep laboratory. The aim was to evaluate
metabolic/cardiovascular markers in snorers and OSAS patients, to relate with sleep parameters
and PAP response. One-hundred and three patients were included, and 73 (71%) were
OSAS patients. OSAS patients were similar to snorers except for higher body mass index
(BMI) and dyslipidemia. Severe OSAS patients showed higher glycemia, HbA1c, insulin, and
insulin resistance, and lower HDL cholesterol in comparison to mild---moderate (p < 0.05,
p < 0.05, p < 0.001, p < 0.001, p < 0.05, respectively). Glycemic profile and triglycerides were
slightly correlated with OSAS severity. 46 OSAS patients were submitted to 6 months of PAP, with a statistical decrease in mean values of homocysteine, glycemia, total and LDL cholesterol(p < 0.05, p < 0.05, p < 0.05, respectively), and in glycemia and LDL cholesterol in severe grouponly (p < 0.05, p < 0.05, respectively).Results: This study demonstrated an association between glucose metabolism parameters andtriglycerides with OSAS severity underlying the complexity of the process leading to cardiovas-cular/metabolic complications in this disorder. Moreover, homocysteine, glycemic and lipidicprofiles changed significantly after 6 months of PAP therapy in OSAS, supporting its cardiovas-cular and metabolic protective effect.Conclusion: Our study has reinforced the importance of analytical cardiovascular/metabolicevaluation as complementary tool of diagnosis/treatment response in OSAS.info:eu-repo/semantics/publishedVersio
Propriedades nutricionais, químicas e bioativas de duas espécies de cogumelos silvestres do género Leccinum, provenientes do Nordeste Transmontano
Os cogumelos são muito apreciados, não apenas pelas suas propriedades organoléticas e nutricionais, mas também pelo seu potencial medicinal e capacidade de produção e acumulação de
compostos bioativos. As suas propriedades antioxidantes e antitumorais têm sido amplamente documentadas, nomeadamente, pelo nosso grupo de investigação [1,2]. No entanto, das numerosas espécies que caracterizam a micoflora transmontana, existem ainda espécies pouco estudadas como
é o caso de Leccinum molle (Bon) Bon e Leccinum vulpinum Watling. Assim sendo, o objetivo do presente trabalho foi caracterizar nutricional e quimicamente amostras silvestres das espécies
referidas, em exemplares provenientes do nordeste transmontano (novembro, 2012). As
propriedades antioxidantes e antitumorais dos seus extratos metanólicos foram também estudadas em condições in vitro. As contribuições energéticas obtidas após determinação dos macronutrientes
foram 391 e 360 kcal/100 g massa seca para L. molle e L. vulpinum, respetivamente. O açúcar presente em maior quantidade em L. molle foi o manitol (11 g/100 g), enquanto que para L. vulpinum foi a trealose (8 g/100 g). A percentagem de ácidos gordos encontrada em L. molle e L. vulpinum foi,
respectivamente: ácidos gordos saturados- 17% (maioritariamente ácido palmítico),
monoinsaturados- 39 e 29% (maioritariamente ácido oleico), polinsaturados- 44 e 54%
(maioritariamente ácido linoleico). Relativamente à vitamina E, a isoforma β-tocoferol foi a maioritária
em L. molle (13 μg/100 g) e γ-tocoferol em L. vulpinum (296 μg/100 g). A composição em ácidos
fenólicos foi 0.19 mg/100 g (ácidos p-hidroxibenzóico e cinâmico) e 0.69 mg/100 g (também os
ácidos gálico e protocatéquico), respetivamente, e em ácidos orgânicos 4 mg/100 g (ácidos oxálico,
cítrico e fumárico) e 0.5 mg/100 g (ácido quínico em vez de cítrico). L. vulpinum apresentou maior
atividade antioxidante em todos os ensaios (atividade captadora de radicais livres, poder redutor e
inibição da peroxidação lipídica): valores de EC50 < 1.2 mg/mL. No que concerne a atividade
antitumoral, esta espécie foi a única que inibiu a proliferação de linhas celulares tumorais humanas
(mama, pulmão, cólon, cervical e hepatocelular), sendo a linha celular HCT-15 a mais susceptível
(carcinoma de cólon; GI50 = 78 μg/mL). Até 400 μg/mL, os extratos não revelaram toxicidade para
células não tumorais (culturas primárias de células de fígado). Este estudo contribui para a
valorização das espécies de cogumelos anteriormente mencionadas, fornecendo mais informação
relativamente à sua composição química e bioatividade
Associação independente da variante rs1333049, no locus 9p21, com a doença coronária, numa população portuguesa
Funding: This study was supported by the European Regional Development Fund’s Operational Programme for the Enhancement of Economic Potential and Territorial Cohesion for the Autonomous Region of Madeira (INTERVIR+).Introduction: Recent genome-wide association studies have identified single-nucleotide polymorphisms (SNPs) at the 9p21 locus as risk factors for coronary artery disease (CAD). Among them, the SNP rs1333049 has demonstrated a consistent association with CAD, which has been successfully replicated in several populations. Aim: To investigate whether the SNP rsl333049 located on the 9p21 chromosome is an independent risk factor for CAD in a Portuguese population. Methods: We performed a case-control study which included 1406 individuals, 723 consecutive coronary patients (mean age 53.7±8.9 years, 79.9% male) and 683 controls without coronary disease (mean age 53.3±10.5 years, 73.9% male). Cases and controls were selected so as not to be significantly different in terms of gender and age. We studied the SNP rs1333049 at the 9p21 locus in all individuals, using standard PCR combined with the TaqMan technique (Applied Biosystems). The allelic and genotype distribution (C/G), odds ratios and corresponding confidence intervals for CAD risk were determined. A forward Wald logistic regression analysis model was constructed, adjusted for age, gender, conventional risk factors, biochemical markers and the genotypes under study, in order to determine which variables were linked significantly and independently with CAD. Results: The C allele was found in 60% of the CAD patients and 53% of the controls, with OR=1.33; p=0.0002. The CC genotype appeared in 35.7% of CAD patients, with OR=1.34, p=0.010. The heterozygous CG genotype was present in 48.1% of the CAD patients and 47% of the controls, and did not present vascular risk (OR=1.05, p=0.670). After logistic regression analysis, the CC genotype remained in the equation with 0R=1.7; p=0.018 and CG with OR=I.5, p=0.048. Conclusion: In the present study we replicated the coronary risk linked to the recently discovered variant rs1333049 on the 9p21 chromosome in a Portuguese population. Although the mechanism underlying the risk is still unknown, the robustness of this risk allele in risk stratification for CAD has been consistent, even in very different populations. The presence of the CC or CG genotype may thus prove to be useful for predicting the risk of developing CAD in the Portuguese population.publishersversionpublishe
Measuring Black Hole Spin using X-ray Reflection Spectroscopy
I review the current status of X-ray reflection (a.k.a. broad iron line)
based black hole spin measurements. This is a powerful technique that allows us
to measure robust black hole spins across the mass range, from the stellar-mass
black holes in X-ray binaries to the supermassive black holes in active
galactic nuclei. After describing the basic assumptions of this approach, I lay
out the detailed methodology focusing on "best practices" that have been found
necessary to obtain robust results. Reflecting my own biases, this review is
slanted towards a discussion of supermassive black hole (SMBH) spin in active
galactic nuclei (AGN). Pulling together all of the available XMM-Newton and
Suzaku results from the literature that satisfy objective quality control
criteria, it is clear that a large fraction of SMBHs are rapidly-spinning,
although there are tentative hints of a more slowly spinning population at high
(M>5*10^7Msun) and low (M<2*10^6Msun) mass. I also engage in a brief review of
the spins of stellar-mass black holes in X-ray binaries. In general,
reflection-based and continuum-fitting based spin measures are in agreement,
although there remain two objects (GROJ1655-40 and 4U1543-475) for which that
is not true. I end this review by discussing the exciting frontier of
relativistic reverberation, particularly the discovery of broad iron line
reverberation in XMM-Newton data for the Seyfert galaxies NGC4151, NGC7314 and
MCG-5-23-16. As well as confirming the basic paradigm of relativistic disk
reflection, this detection of reverberation demonstrates that future large-area
X-ray observatories such as LOFT will make tremendous progress in studies of
strong gravity using relativistic reverberation in AGN.Comment: 19 pages. To appear in proceedings of the ISSI-Bern workshop on "The
Physics of Accretion onto Black Holes" (8-12 Oct 2012). Revised version adds
a missing source to Table 1 and Fig.6 (IRAS13224-3809) and corrects the
referencing of the discovery of soft lags in 1H0707-495 (which were in fact
first reported in Fabian et al. 2009
Proteins and their peptide motifs in acellular apatite mineralization of scaffolds for tissue engineering
Many proteins in the inorganic=organic matrix of bone induce or modulate or inhibit mineralization of apatite
in vivo. Many attempts have been made to mimic and understand this mechanism as part of bone formation, and
ectopic mineralization and control thereof. Many attempts have also been made to use such proteins or protein
fragments to harness their potential for improved mineralization. Such proteins and peptide motifs have also been
the inspiration for attempts of making mimics of their structures and motifs using chemical or biological synthesis.
The aim of this review is to highlight how proteins and (poly)peptides themselves impact mineralization
in the human body, and how those could be used and have been used for improving apatite mineralization, for
example, on or in materials that by themselves do not induce apatite mineralization but otherwise have interesting
properties for use as bone tissue engineering scaffolds.J. Benesch wishes to acknowledge the financial support from FCT, postdoctoral fellowship scholarship SFRH/BPD/17584/2004. This work was carried out under the scope of the European Union NoE EXPERTISSUES (NMP3-CT-2004500283) and partially funded by the European Union FP6 STREP Project HIPPOCRATES (NMP3-CT-2003-505758) and FCT project ProteoLight (PTDC/FIS/68517/2006)
An overview of jets and outflows in stellar mass black holes
In this book chapter, we will briefly review the current empirical
understanding of the relation between accretion state and and outflows in
accreting stellar mass black holes. The focus will be on the empirical
connections between X-ray states and relativistic (`radio') jets, although we
are now also able to draw accretion disc winds into the picture in a systematic
way. We will furthermore consider the latest attempts to measure/order jet
power, and to compare it to other (potentially) measurable quantities, most
importantly black hole spin.Comment: Accepted for publication in Space Science Reviews. Also to appear in
the Space Sciences Series of ISSI - The Physics of Accretion on to Black
Holes (Springer Publisher
Accretion and ejection in black-hole X-ray transients
Aims: We summarize the current observational picture of the outbursts of
black-hole X-ray transients (BHTs), based on the evolution traced in a
hardness-luminosity diagram (HLD), and we offer a physical interpretation.
Methods: The basic ingredient in our interpretation is the Poynting-Robertson
Cosmic Battery (PRCB, Contopoulos & Kazanas 1998), which provides locally the
poloidal magnetic field needed for the ejection of the jet. In addition, we
make two assumptions, easily justifiable. The first is that the mass-accretion
rate to the black hole in a BHT outburst has a generic bell-shaped form. This
is guaranteed by the observational fact that all BHTs start their outburst and
end it at the quiescent state. The second assumption is that at low accretion
rates the accretion flow is geometrically thick, ADAF-like, while at high
accretion rates it is geometrically thin.
Results: Both, at the beginning and the end of an outburst, the PRCB
establishes a strong poloidal magnetic field in the ADAF-like part of the
accretion flow, and this explains naturally why a jet is always present in the
right part of the HLD. In the left part of the HLD, the accretion flow is in
the form of a thin disk, and such a disk cannot sustain a strong poloidal
magnetic filed. Thus, no jet is expected in this part of the HLD. The
counterclockwise traversal of the HLD is explained as follows: the poloidal
magnetic field in the ADAF forces the flow to remain ADAF and the source to
move upwards in the HLD rather than to turn left. Thus, the history of the
system determines the counterclockwise traversal of the HLD. As a result, no
BHT is expected to ever traverse the entire HLD curve in the clockwise
direction.
Conclusions: We offer a physical interpretation of accretion and ejection in
BHTs with only one parameter, the mass transfer rate.Comment: Accepted for publication in A&
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