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S Martins

Publications and source records attributed to S Martins.

At least 19 recordsLinked to original sources
PubMed2006

Kinetic properties of wild-type and altered recombinant amidases by the use of ion-selective electrode assay method.

A novel assay method was investigated for wild-type and recombinant mutant amidases (EC 3.5.1.4) from Pseudomonas aeruginosa by ammonium ion-selective electrode (ISE). The initial velocity is proportional to the enzyme concentration by using the wild-type enzyme. The specific activities of the purified amidase were found to be 88.2 and 104.2 U mg protein(-1) for the linked assay and ISE methods, respectively. The kinetic constants--Vmax, Km, and Kcat--determined by Michaelis-Menten plot were 101.13 U mg protein(-1), 1.12x10(-2) M, and 64.04 s(-1), respectively, for acrylamide as the substrate. On the other hand, the lower limit of detection and range of linearity of enzyme concentration were found to be 10.8 and 10.8 to 500 ng, respectively, for the linked assay method and 15.0 and 15.0 to 15,000 ng, respectively, for the ISE method. Hydroxylamine was found to act as an uncompetitive activator of hydrolysis reaction catalyzed by amidase given that there is an increase in Vmax and Km when acetamide was used as the substrate. However, the effect of hydroxylamine on the hydrolysis reaction was dependent on the type of amidase and substrate involved in the reaction mixture. The degrees of activation (epsilon(a)) of the wild-type and mutant (T103I and C91A) enzymes were found to be 2.54, 12.63, and 4.33, respectively, for acetamide as the substrate. However, hydroxylamine did not activate the reaction catalyzed by wild-type and altered (C91A and W138G) amidases by using acrylamide and acetamide, respectively, as the substrate. The activating effect of hydroxylamine on the hydrolysis of acetamide, acrylamide, and p-nitrophenylacetamide can be explained by the fact that additional formation of ammonium ions occurred due to the transferase activity of amidases. However, the activating effect of hydroxylamine on the hydrolysis of p-nitroacetanilide may be due to a change in conformation of enzyme molecule. Therefore, the use of ISE permitted the study of the kinetic properties of wild-type and mutant amidases because it was possible to measure initial velocity of the enzyme-catalyzed reaction in real time.

Acetamides↗
PubMed2006

The role of adrenergic receptor polymorphisms in heart failure.

The main function of the cardiac adrenergic system is to regulate cardiac work both in physiologic and pathologic states. A better understanding of this system has permitted the elucidation of its role in the development and progression of heart failure. Regardless of the initial insult, depressed cardiac output results in sympathetic activation. Adrenergic receptors provide a limiting step to this activation and their sustained recruitment in chronic heart failure has proven to be deleterious to the failing heart. This concept has been confirmed by examining the effect of beta-blockers on the progression of heart failure. Studies of adrenergic receptor polymorphisms have recently focused on their impact on the adrenergic system regarding its adaptive mechanisms, susceptibilities and pharmacological responses. In this article, we review the function of the adrenergic system and its maladaptive responses in heart failure. Next, we discuss major adrenergic receptor polymorphisms and their consequences for heart failure risk, progression and prognosis. Finally, we discuss possible therapeutic implications resulting from the understanding of polymorphisms and the identification of individual genetic characteristics.

Cardiac Output, Low↗
PubMed2005

Evaluation of candidate probiotic strains for gilthead sea bream larvae (Sparus aurata) using an in vivo approach.

AIMS: The aim of this study was to evaluate the effect of six bacterial strains on gilthead sea bream larvae (Sparus aurata). METHODS AND RESULTS: Six bacterial strains isolated from well-performing live food cultures were identified by sequencing fragments of their 16s rDNA genome to the genus level as Cytophaga sp., Roseobacter sp., Ruergeria sp., Paracoccus sp., Aeromonas sp. and Shewanella sp. Survival rates of gilthead sea bream larvae transferred to seawater added these bacterial strains at concentrations of 6 +/- 0.3 x 10(5) bacteria ml(-1) were similar to those of larvae transferred to sterilized seawater and showed an average of 86% at 9 days after hatching, whereas, survival rates of larvae transferred to filtered seawater were lower (P < 0.05), and showed an average of 39%, 9 days after hatching. CONCLUSION: Several bacterial strains isolated from well-performing live food cultures showed a positive effect for sea bream larvae when compared with filtered seawater. SIGNIFICANCE AND IMPACT OF THE STUDY: The approach used in this study could be applied as an in vivo evaluation method of candidate probiotic strains used in the rearing of marine fish larvae.

Aeromonas↗
PubMed2004

Transbronchial administration of adenoviral-mediated interleukin-10 gene to the donor improves function in a pig lung transplant model.

Interleukin-10 (IL-10) gene transfection of donor lungs prior to transplantation is an attractive strategy to reduce ischemia-reperfusion induced lung injury. However, experimental data with gene therapy in large animal models of lung transplantation are generally lacking. We have developed a simple clinically applicable technique for adenoviral-mediated gene delivery of human IL-10 to the lung of large animals that provides homogenous gene expression after 12-24 h of transfection. Using this technique of gene delivery, we have studied the dynamics of adenoviral gene delivery to the lung in the setting of lung transplantation. Although there is a persistent inflammatory response to the adenoviral vector, we achieved significant expression of human IL-10 in lung tissue before lung retrieval to obviate the deleterious impact of the adenoviral vector on the donor lung. The administration of adenoviral-mediated human IL-10 to the donor lung reduced ischemia-reperfusion injury and improved graft function after lung transplantation in this pig lung transplantation model. Transfection of adenoviral-mediated human IL-10 to the donor lung prevented the release of inflammatory cytokines such as IL-6 in lung tissue and plasma. We have demonstrated that IL-10 gene therapy has significant potential to prevent or treat the inflammatory response associated with ischemia-reperfusion injury in lung transplantation. In the future, IL-10 gene therapy could also be used for immunomodulation or tolerance induction.

Adenoviridae↗
PubMed2003

Body surface area estimation and its impact on predicting appendicular skeletal muscle mass with a mechanistic model based on the Reference Man.

The purpose of this study was to analyze the difference between the equations presented by Du Bois and Du Bois (1916) and Livingston and Lee (2001), used to estimate body surface area (BSA) and its impact on predicting appendicular skeletal muscle mass (ASMM) in adults, using a model based on the Reference Man (Fuller et al. 1992). Subjects were 666 Caucasian women (44.3+/-15.2 years, 63.7+/-10.5 kg, 1.57+/-0.07 m, 26.0+/-4.3 kg/m(2)) and 316 Caucasian men (42.8+/-15.4 years, 79.8+/-12.5 kg, 1.72+/-0.07 m, 26.8+/-3.8 kg/m(2)). Dual-energy X-ray absorptiometry was used to assess fat mass and fat-free mass. Du Bois's and Livingston's BSA equations were used to calculate ASMM according to Fuller's method. As compared to the new Livingston equation, Du Bois's equation underestimated ( p<0.05) BSA in women (-0.08 m(2)) and in men (-0.06 m(2)). On the other hand, ASMM was overestimated in the arms, legs, and total body with Du Bois's equation. This effect was of greater magnitude in obese subjects.

Absorptiometry, Photon↗
PubMed2002

Haplotype study of microsatellites flanking the t(15;17) breakpoint in acute promyelocytic leukemia patients from North Portugal.

A higher frequency of acute promyelocytic leukemia (APL) has been noted in countries of Southern Europe and among 'Latino' patients of the United States with acute myeloid leukemia (AML). In order to discover whether there is any genetic predisposition to the disease, we analyzed microsatellites flanking PML and RARalpha genes in 29 t(15;17) APL patients from North Portugal and compared them with a control group of 123 healthy individuals. Fluorescent PCR products were analyzed using an automated capillary electrophoresis system and allele and haplotype frequencies of the two populations were determined. No significant differences were found, suggesting the same genetic origin of patients and healthy individuals. As suggested by the four microsatellites screened, MSI (microsatellite instability) does not explain the increased incidence of t(15;17) APL in this Portuguese population. These results intend to be a new approach to the study of APL, reflecting the particularity of the disease.

Chromosomes, Human, Pair 15↗
PubMed2001

Iron therapy for improving psychomotor development and cognitive function in children under the age of three with iron deficiency anaemia.

BACKGROUND: Iron deficiency and iron deficiency anaemia (IDA) are common in young children. It has been suggested that the lack of iron may have important effects on children's psychomotor development and cognitive function. OBJECTIVES: To determine the effects of iron therapy on psychomotor development and cognitive function in iron deficient children less than 3 years of age. SEARCH STRATEGY: The following databases were searched: COCHRANE LIBRARY (2000 ISSUE 4) MEDLINE (1966-August 2000) EMBASE (1980-August 2000) Latin American Database (LILACS) PsycLIT Journal articles (1974-August 2000) PsycLIT Chapters and Books (1987-August 2000) The references of identified trials and of important review articles were scrutinised. Citation searches on trials from the primary search were performed within the Science Citation Index. Key authors were contacted. SELECTION CRITERIA: Studies were included if children less than 3 years of age with evidence of iron deficiency anaemia were randomly allocated to iron or iron and vitamin C versus a placebo or vitamin C alone and assessment of developmental status or cognitive function was carried out using standardised tests by observers blind to treatment allocation. DATA COLLECTION AND ANALYSIS: Abstracts and titles of studies identified on searches of electronic databases were read to determine whether they might meet the inclusion criteria. Full copies of those possibly meeting these criteria from electronic or other searches were assessed by two independent reviewers. Differences of opinion about suitability for inclusion were resolved by discussion. Data were analysed separately depending on whether participants had iron assessments were performed within one month of beginning iron therapy or later. MAIN RESULTS: Five trials, including 180 children with IDA, examined the effects of iron therapy on measures of psychomotor development between 5 and 11 days of commencement of therapy. Data from four trials could be pooled. The pooled difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups was -3.2 (95%CI -7.24, 0.85) and in Bayley Scale MDI, 0.55 (95% CI -2.84, 1.75). Two studies, including 160 randomised children with IDA, examined the effects of iron therapy on measures of psychomotor development more than 30 days after commencement of therapy. Aukett et al reported the mean number of skills gained after two months of iron therapy, using the Denver test. The intervention group gained 0.8 (95% CI -0.18, 1.78) more skills on average than the control group. Idjrandinata et al reported that the difference in pre to post treatment change in Bayley Scale PDI between iron treated and placebo groups after 4 months was 18.40 (95%CI 10.16, 26.64) and in Bayley Scale MDI, 18.80 (95% CI 10.19, 27.41). REVIEWER'S CONCLUSIONS: There is no convincing evidence that iron treatment of young children with IDA has an effect on psychomotor development discernable within 5-11 days. The effect of longer term treatment remains unclear but the data would be compatible with clinically significant benefit. There is urgent need for further randomised controlled trials with long term follow up.

Anemia, Iron-Deficiency↗
PubMed2001

Non-invasive monitoring of pulmonary capillary wedge pressure in heart failure.

OBJECTIVE: To evaluate the usefulness of pulsed Doppler (PD) mitral flow E wave deceleration time (EDcT) to detect and quantify changes of pulmonary capillary wedge pressure (PCWP) in patients (pt) with dilated chronic heart failure (CHF) submitted to tailored therapy. METHODS: In 14 pt with dilated cardiomyopathy (DCM) (59.4+/-10.0 years, 11 males, sinus rhythm), admitted to the ICU because of worsening CHF, serial simultaneous hemodynamic and echocardiographic studies were performed (3-5/pt; overall 49 evaluations). PD mitral flow register was used to measure EDcT and correlated with PCWP at each study. RESULTS: PCWP ranged from 36 to 3 mmHg (17.6+/-8.8) and EDcT from 271 to 52 ms (104.9+/-42.4). The correlation between EDcT and PCWP was -0.65 (PCWP=31.7-0.134EDcT). Using this equation to calculate PCWP, individual absolute values difference (identity error - IE) was 5.6+/-3.5 mmHg (0.4-14.6). In 29 cases (59.2%) IE was >5 mmHg, defined as major error. Considering EDcT percent change (delta%EDcT) and PCWP variation (deltaPCWP) in serial evaluations, we found a correlation of -0.87 (deltaPCWP=-2.83-0.19 delta%EDcT). Using this equation, the IE was 2.3+/-1.6 mmHg (0-5.2) and there were only two (6%) major errors (P<0.0001). CONCLUSIONS: In pt with DCM and advanced CHF, EDcT shows a reasonable correlation with PCWP, but when it is used to calculate PCWP the IE to hemodynamic values is often large. However, our results with EDcT percent change in serial evaluations using a first simultaneous invasive determination, suggest that this technique is reliable for monitoring PCWP and can be particularly useful for pt submitted to tailored therapy.

Adult↗
PubMed2001

School dropout and conduct disorder in Brazilian elementary school students.

OBJECTIVES: To evaluate the association between DSM-IV conduct disorder (CD) and school dropout in a sample of students from the third and fourth elementary grades at state schools in the capital of the southernmost state of Brazil. METHODS: In this case-control study, students that dropped out of schools (n = 44) and a control group who continued attending schools (n = 44) were assessed for CD and other prevalent mental disorders, using the Schedule for Affective Disorders and Schizophrenia for School Age Children, Epidemiological Version (K-SADS-E). RESULTS: The prevalence of DSM-IV CD was significantly higher in the school-dropout group than in control subjects (P < 0.001), both in the entire sample and in a subsample including only subjects under age 12 years (P = 0.001). Also, the odds ratio (OR) for school dropout was significantly higher in the presence of DSM-IV CD, even after controlling for potential confounding factors (age, estimated IQ, school repetition, family structure, and income) (P < 0.01). CONCLUSION: Our results extend to children and young adolescents previous findings from studies of older adolescents, suggesting an association between school dropout and CD.

Adolescent↗
PubMed2001

Early and medium term results of tailored therapy for heart failure.

UNLABELLED: Patients (pts) with advanced chronic heart failure, in NYHA functional class IV, refractory to conventional medical therapy, show a poor short-term survival prognosis. Heart transplant remains the therapy of choice but it can currently be performed in only a minority of pts. Therapy tailored to hemodynamic goals has been suggested as a potential alternative for patients with advanced congestive heart failure. Intravenous and, subsequently, oral vasodilators (v) and diuretics (d) are titrated, in order to achieve specific hemodynamic parameters: systolic arterial pressure (SAP) > 80 mmHg, pulmonary wedge pressure (PWP) < 15 mmHg, right atrial pressure (RAP) < 8 mmHg, and systemic vascular resistance (SVR) < 1200 dynes.sec.cm-5. AIM: To assess short and medium term (two years) results of a tailored therapy management program for treatment of patients with advanced heart failure. METHODS: 27 pts (19 males, 61 +/- 10 years), NYHA functional class IV, with dilated cardiomyopathy (13 idiopathic, 10 ischemic, 4 hypertensive), 17 with exclusion criteria for heart transplantation, were included. Echocardiographic left ventricular end-diastolic dimension and ejection fraction were 68 +/- 8 mm and 20 +/- 9%, respectively. Initial (i) serum sodium (Na+) was 136 +/- 5 mEq/l and i serum creatinine (Cr) was 1.4 +/- 0.8 mg/dl. Baseline, at referral, hemodynamics: SAP = 125 +/- 23, PWP = 23 +/- 6, RAP = 12 +/- 6, cardiac index (CI) = 1.9 +/- 0.5 l/min/m2, SVR = 2193 +/- 670. Using bedside right heart catheterization (Swan-Ganz catheter) we set out to achieve the above hemodynamic goals. RESULTS: 1) v and d used: sodium nitroprusside--cumulative dose = 196 +/- 121 mg, captopril--daily dose (dd) = 157 +/- 95 mg, isosorbide dinitrate--dd = 91 +/- 57 mg, hydralazine--dd = 95 +/- 67 mg, and furosemide--dd = 105 +/- 70 mg; 2) final (f) hemodynamic parameters on tailored therapy: SAP = 109 +/- 20*, PWP = 12 +/- 3*, RAP = 4 +/- 3*, CI = 2.5 +/- 0.6*, SVR = 1317 +/- 340* (*: p < 0.001 vs baseline); 3) duration of invasive monitoring was 3.0 +/- 1.9 days; 4) f Na+ = 134 +/- 5, and f Cr = 1.5 +/- 0.8 (NS vs i); 5) there was one (4%) in-hospital death; functional class of discharged pts: III--4 pts, II--18 pts, I--4 pts; 6) nine pts (35%) died after discharge--three due to refractory heart failure and six (including two potential heart transplant candidates) had sudden death; 7) actuarial survival (Kaplan-Meyer method): at 6 months (m)--80%, 12 m--71%, 18 m--64%, 24 m--55%; 8) after a mean follow-up of 18 +/- 8 m, functional class in survivors was: NYHA IV--2 pts, III--4 pts, II--8 pts, and I--3 pts. CONCLUSIONS: Therapy tailored to hemodynamic goals is a valid approach for pts with advanced heart failure, showing good hemodynamic and functional short-term results, and reasonable survival at two years. The significant incidence of sudden death demands strategies for risk stratification and a search for prophylactic measures in this population.

Female↗
PubMed2001

Patient safety in guideline-based decision support for hypertension management: ATHENA DSS.

The Institute of Medicine recently issued a landmark report on medical error.1 In the penumbra of this report, every aspect of health care is subject to new scrutiny regarding patient safety. Informatics technology can support patient safety by correcting problems inherent in older technology; however, new information technology can also contribute to new sources of error. We report here a categorization of possible errors that may arise in deploying a system designed to give guideline-based advice on prescribing drugs, an approach to anticipating these errors in an automated guideline system, and design features to minimize errors and thereby maximize patient safety. Our guideline implementation system, based on the EON architecture, provides a framework for a knowledge base that is sufficiently comprehensive to incorporate safety information, and that is easily reviewed and updated by clinician-experts.

Artificial Intelligence↗
PubMed2000

Exploring ADHD age-of-onset criterion in Brazilian adolescents.

OBJECTIVE: To explore age-of-onset criterion for the diagnosis of attention-deficit hyperactivity disorder (ADHD) in a school sample of young Brazilian adolescents. METHODS: 191 students aged 12 to 14 years were evaluated using DSM-IV ADHD criteria, measures of ADHD symptoms and global impairment. RESULTS: Both adolescents with ADHD (n = 30) and adolescents who fulfilled all DSM-IV ADHD criteria, except age of onset of impairment criterion (ADHD w/o age-of-onset, n = 27) had significantly higher scores on Attention Problems, Delinquent and Aggressive Behavior scales of the Child Behavior Checklist (CBCL) and lower scores on the Child Global Assessment scale (CGAS) than non-ADHD adolescents (n = 134). Adolescents with ADHD and youths with ADHD w/o age-of-onset did not differ significantly in any measure assessed. CONCLUSION: These results concur with recent literature proposing revision of the age-of-onset criterion for the diagnosis of ADHD.

Adolescent↗
PubMed2000

Density mismatch in thin diblock copolymer films

Thin films of diblock copolymer subject to gravitational field are simulated by means of a cell dynamical system model. The difference in density of the two sides of the molecule and the presence of the field causes the formation of lamellar patterns with orientation parallel to the confining walls even when they are neutral. The concentration profile of those films is analyzed in the weak segregation regime and a functional form for the profile is proposed.

Journal Article↗
PubMed2000

Cardiac output quantification by Doppler echocardiography in intensive care--limitations and validation.

UNLABELLED: Cardiac output (CO) quantification is primordial to the evaluation of patients with heart failure who are on tailored therapy and under invasive hemodynamic monitoring. Doppler echocardiography can be used to access CO noninvasively, but the concordance between its results and those obtained by invasive methods in paired measurements is still controversial. To our knowledge, no previous studies have assessed the clinical relevance of Doppler echocardiography for CO serial evaluation in patients submitted to tailored therapy. AIM: To evaluate the usefulness of echo-Doppler in the assessment of CO and quantification of changes in CO, compared to thermodilution, in patients with advanced heart failure under hemodynamic monitoring to guide tailored therapy. METHODS: In 20 patients (14 male, 62 +/- 14 years old, all in sinus rhythm), with dilated cardiomyopathy and NYHA IV, admitted to the intensive care unit (ICU), CO was simultaneously determined by Doppler echocardiography (dpCO) and thermodilution (tdCO) in three serial evaluations (overall 60). The dpCO was calculated by multiplying the aortic orifice area by the velocity-time integral of aortic continuous wave Doppler flow and by the heart rate. A difference between tdCO and dpCO of more than 20% was considered a major error. RESULTS: In the overall evaluations, dpCO systematically overestimates tdCO (p = 0.026). The correlation between tdCO and dpCO was 0.81, the mean difference between measurements was 0.40 +/- 0.61 l/min (mean -2SD = -1.62 mean +2SD = 0.81) and 19 (32%) major errors occurred. No significant difference was found between CO percentual variation values assessed by both methods, with a stronger correlation (r = 0.92-p = 0.014) compared to that found for absolute values. On using the dpCO/tdCO ratio in the first evaluation to correct subsequent dpCO, the correlation was fairly good (r = 0.96-p = 0.0002 versus corrected dpCO). The mean difference between paired measurements was significantly lower (0.12 +/- 0.28 l/min-mean 2SD = -0.44 mean +2SD = 0.67), and there were no errors. CONCLUSIONS: CO estimated by Doppler echocardiography has a good correlation with thermodilution although with a weak concordance between paired results in patients with dilated cardiomyopathy and advanced heart failure admitted to the ICU for tailored therapy. Our results with dpCO percentual change in repeated evaluations and with corrected dpCO value after a single simultaneous invasive determination suggest that Doppler echocardiography is a valid method for clinical purposes, allowing us to propose a reduction in the time period of invasive hemodynamic monitoring.

Adult↗