Publications by authors named "Valente F"

The type of hemodialysis vascular access (fistula, graft, catheter) employed plays an important role in the results of dialysis treatment. Moreover, different complications can affect the vascular access and interfere with the morbidity and mortality of patients. The ideal vascular access is the Cimino Brescia fistula, followed by graft.

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Background: The recent increase in the incidence of clinical depression represents a major public health and socio-economical burden. Depression has its roots in both professional and private domains but few epidemiological studies have looked at predictors of long term clinical depression as defined by a sick-leave of 28 days or more and a diagnosis by a general practitioner in both genders.

Objectives: To study baseline predictors of long term spells of clinical depression within the framework of a large prospective study, the Belstress Study, in 6,659 men and 2,737 women aged 35-59 years at baseline survey.

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Non classical bioisosters of modafinil featuring interesting biological profile have been easily produced through replacement of the sulfoxide function with a carbonyl group and modification of the carboxylic acid amide functionality.

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The gram-negative anaerobic gut bacterium Bilophila wadsworthia is the third most common isolate in perforated and gangrenous appendicitis, being also found in a variety of other infections. This organism performs a unique kind of anaerobic respiration in which taurine, a major organic solute in mammals, is used as a source of sulphite that serves as terminal acceptor for the electron transport chain. We show here that molecular hydrogen, one of the major products of fermentative bacteria in the colon, is an excellent growth substrate for B.

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Sulphate-reducing bacteria are important players in the global sulphur and carbon cycles, with considerable economical and ecological impact. However, the process of sulphate respiration is still incompletely understood. Several mechanisms of energy conservation have been proposed, but it is unclear how the different strategies contribute to the overall process.

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Desulfovibrio vulgaris Hildenborough has a membrane-bound [NiFeSe] hydrogenase whose mode of membrane association was unknown since it is constituted by two hydrophilic subunits. This work shows that this hydrogenase is a bacterial lipoprotein bound to the membrane by lipidic groups found at the N-terminus of the large subunit, which is unusual since it is missing the typical lipoprotein signal peptide. Nevertheless, the large subunit has a conserved four residue lipobox and its synthesis is sensitive to the signal peptidase II inhibitor globomycin.

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In the Mediterranean evergreen oak woodlands of southern Portugal, the main tree species are Quercus ilex ssp. rotundifolia Lam. (holm oak) and Quercus suber L.

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The cytochrome c nitrite reductase (cNiR) isolated from Desulfovibrio vulgaris Hildenborough is a membrane-bound complex formed of NrfA and NrfH subunits. The catalytic subunit NrfA is a soluble pentahaem cytochrome c that forms a physiological dimer of about 120 kDa. The electron-donor subunit NrfH is a membrane-anchored tetrahaem cytochrome c of about 18 kDa molecular weight and belongs to the NapC/NirT family of quinol dehydrogenases, for which no structures are known.

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Desulfovibrio vulgaris Hildenborough is a good model organism to study hydrogen metabolism in sulfate-reducing bacteria. Hydrogen is a key compound for these organisms, since it is one of their major energy sources in natural habitats and also an intermediate in the energy metabolism. The D.

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Resonance Raman (RR) spectroscopy was used to investigate conformational characteristics of the hemes of several ferricytochromes of the cytochrome c3 family, electron transfer proteins isolated from the periplasm and membranes of sulfate-reducing bacteria. Our analysis concentrated on the low-frequency region of the RR spectra, a fingerprint region that includes vibrations for heme-protein C-S bonds [nu(C(a)S)]. It has been proposed that these bonds are directly involved in the electron transfer process.

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The genome of Desulfovibrio vulgaris Hildenborough (DvH) encodes for six hydrogenases (Hases), making it an interesting organism to study the role of these proteins in sulphate respiration. In this work we address the role of the [NiFeSe] Hase, found to be the major Hase associated with the cytoplasmic membrane. The purified enzyme displays interesting catalytic properties, such as a very high H(2) production activity, which is dependent on the presence of phospholipids or detergent, and resistance to oxygen inactivation since it is isolated aerobically in a Ni(II) oxidation state.

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Background: Oxidative stress profoundly influences the biochemistry of proteins and many other molecules in tissues of uremic patients. In three different groups of uremic patients, the concentrations of the free and bound pentosidine and low-molecular-weight-advanced glycoxydation end products (LMW-AGEs), carbonyls (LMW-C), advanced oxidation protein products (AOPP) and the total antioxidant power of serum were studied in order to determine the relationships between these factors in hemodialytic and transplanted patients.

Patients And Methods: The above-mentioned parameters were determined in 10 subjects who were currently in hemodialysis (HD) treatment, 10 kidney transplanted patients with chronic renal failure (Tx-CRF), 10 kidney transplanted patients with normal renal function (Tx-N) and 10 healthy subjects (Ctr).

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Background: It is well-known that hemodialysis patients experience increased oxidative stress, which is believed to cause numerous uremia-related complications. Retention of water-soluble toxins as well as protein-bound toxins is due to renal failure. Kidney transplantation restores, at least partially, the fundamental processes of glomerular filtration which eliminates toxic solutes.

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Context: Sick leave is a major problem in public health. The Karasek demands/control/social support/strain (JDCS) model has been largely used to predict a wide range of health outcomes and to a lesser extent sickness absence.

Study Objective: The aim of the study was to test the predictive power of the JDCS model in relation with one year incidence of sick leave in a large cohort of workers.

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Objectives: In many studies, obesity has been associated with morbidity or mortality, but only a few have studied the relation between obesity and sick leave. Our aim is to analyse the independent effects of both adiposity and body fat distribution in relation to the 1-y incidence of sick leave in a large cohort of male and female workers covering a variety of occupations, taking into account a wide range of socio-demographic, behavioural and bioclinical variables.

Design And Setting: The baseline survey of the Belstress study was conducted in 25 companies across Belgium between 1994 and 1998.

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Objective: To study the predictive power of serum selenium with regard to cancer mortality in a large sample of the Belgian population given the lack of coherence in the results of observational epidemiological studies in this domain.

Design: A prospective case-control study within a stratified sample of the Belgian male and female population.

Subjects: A total of 201 cases randomly selected from all cancer deaths (N=343) during a 10-y mortality follow-up of a large age- and sex-stratified sample of the total Belgian population aged 25-74 y were matched for age and gender with 603 controls.

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Objective: Sigh, defined as an isolated breath with an increased tidal volume, can be associated with abrupt changes in heart rate (HR) or blood oxygenation. Sigh may be followed by a central apnea. As impairment of autonomic control was postulated in future SIDS victims, we hypothesized that their autonomic responses to sighs were different from those of healthy control infants.

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Background: Hypertension and left ventricular hypertrophy (LVH) are present in the majority of patients undergoing haemodialysis (HD). These two pathologies persist after dialysis onset, and pharmacological therapy is often required for adequate control of blood pressure (BP). Although fluid overload is a determinant of hypertension, clinical assessment of this parameter remains difficult and unsatisfactory.

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In the present study, we report the identification of an operon with six coding regions for a multisubunit membrane-bound [NiFe] hydrogenase in the genome of Desulfovibrio gigas. Sequence analysis of the deduced polypeptides reveals a high similarity to subunits of proteins belonging to the family of Ech hydrogenases. The operon is organised similarly to the operon coding for the Ech hydrogenase from Methanosarcina barkeri, suggesting that both encode very similar hydrogenases.

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A detailed anatomic study was carried out on the lateral femoral cutaneous nerve to better understand the etiology and treatment of lateral femoral cutaneous neuralgia. As it passed from the pelvis into the thigh, the lateral femoral cutaneous nerve ran through an "aponeuroticofascial tunnel," beginning at the iliopubic tract and ending at the inguinal ligament; as it passed through the tunnel, an enlargement in its side-to-side diameter was observed, suggesting that the fascial structures proximal to the inguinal ligament may be implicated in the genesis of lateral femoral cutaneous neuralgia. The finding of pseudoneuromas at this location, distant from the inguinal ligament, supports this hypothesis.

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The risk of Sudden Infant Death Syndrome is increased in infants sleeping with their head covered by bedding items. This study was designed to evaluate cardiac autonomic nervous controls in infants sleeping with the head covered by bedclothes. Sixteen healthy infants with a median age of 12 weeks (range 9-13 weeks) were recorded polygraphically for one night.

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Background: The aim of the research was to isolate and to identify the methicillin-resistant Staphylococcus aureus (MRSA) strains from cattle and human and to determine their genetic relatedness comparing the DNA restriction patterns.

Methods: Strains of Staphylococcus aureus were isolated from animals (223 strains) and humans (83). The E-test was applied to determine methicillin-resistance.

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A case of unilateral congenital hydrothorax diagnosed at 21 weeks and treated with a pleuro-amniotic shunt at 23 weeks' gestation is presented. The rapid production of pleural fluid led to the development of polyhydramnios which was treated with a selective Cox inhibitor. Due to worsening of the hydrothorax, a third thoracocentesis was performed at 30 weeks' gestation prior to a Cesarean section.

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