Biomedical subjects

Fábio Fernandes

Publications and source records attributed to Fábio Fernandes.

13 recordsLinked to original sources

PubMed2006

Absence of clustering of phosphatidylinositol-(4,5)-bisphosphate in fluid phosphatidylcholine.

Phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P(2)] plays a key role in the modulation of actin polymerization and vesicle trafficking. These processes seem to depend on the enrichment of PI(4,5)P(2) in plasma membrane domains. Here, we show that PI(4,5)P(2) does not form domains when in a fluid phosphatidylcholine matrix in the pH range of 4.8-8.4. This finding is at variance with the spontaneous segregation of PI(4,5)P(2) to domains as a mechanism for the compartmentalization of PI(4,5)P(2) in the plasma membrane. Water/bilayer partition of PI(4,5)P(2) is also shown to be dependent on the protonation state of the lipid.

Cell Compartmentation↗

PubMed2006

[NT pro-BNP levels in pericardial diseases and how they are used as complementary evaluation method of diastolic restriction. Initial experience: 25 cases].

OBJECTIVE: To determine whether NT pro-BNP levels are high in patients reporting pericardial diseases, as well as to investigate how they relate to diastolic dysfunction echocardiographic measures. METHODS: Twenty-five patients were split into two groups: 1) pericardial effusion (PE): 15 patients; 2) constrictive pericarditis (CP): 10 patients. A control group was made up with 30 individuals reporting no heart disease. Pericardial effusion was evaluated by bidimensional echocardiogram, with restriction evaluated by pulsed Doppler of mitral flow. CP diagnosis was confirmed by MRI. NT pro-BNP levels were measured by immunoassay and detected by electrochemiluminescence. RESULTS: From the 15 PD patients, 14 reported relevant PD, and only 1, moderate PD. Log NT pro-BNP was shown to be higher in PD (p < 0.05), with log mean of 2.31 pg/ml and CP (p < 0.05), with log mean of 2.67 pg/ml, when compared to control group, log mean of 1.32 pg/ml. No difference was reported between PD and CP (p = 0.149). The NT pro-BNP log showed to be correlated to peak velocity of the E wave (r = 0.845; p = 0.001) and with E/A (r = 0.717; p = 0.003). CONCLUSION: NT pro-BNP is shown to have increased in pericardial diseases, and is associated to diastolic dysfunction. It may serve as an additional method in quantifying restriction.

Adolescent↗

PubMed2006

Aldosterone antagonism in an inflammatory state: evidence for myocardial protection.

INTRODUCTION: Chagas' disease is one of the most important causes of dilated cardiomyopathy in South and Central America. It is an inflammatory cardiomyopathy. We wanted to investigate whether it could have the same response to aldosterone antagonism as demonstrated before in other dilated cardiomyopathies. OBJECTIVE: To evaluate the role of spironolactone in myocardial remodelling in a Chagas cardiomyopathy model. MATERIAL AND METHODS: We studied 60 Sirius Hamsters divided into: control (C) infected (Inf) and Inf plus spironolactone (Infsp, 40 mg/kg/day) groups, for 11 months. Echocardiography with colour doppler was performed. Left ventricular end diastolic diameter (LVEDD), fractional shortening (FS) and corrected isovolumic relaxation time (IRT) were evaluated, as well as interstitial collagen volume fraction (ICVF) and myocardial inflammation. RESULT: The results demonstrated that survival was improved by use of spironolactone in the chronic phase (p<0.04). Body weight (BW) was C:190 g, Inf:167 g*, Infsp:198 g (*p<0.05, compared to C and Infsp), LVEDD/BW was C:0.31, Inf: 0.35*, Infsp: 0.29 (*p<0.05, compared to C and Infsp), FS was C:38, Inf: 35.5, Infsp: 38 (with no statistical difference) and IRT was C: 23 msec, Inf: 26 msec*, Infsp: 22 msec (p<0.05, compared to C and Infsp). ICVF (%) was attenuated at LV (C: 0.34+/-0.1, Inf: 1.75+/-0.7*, Infsp: 0.95+/-0.2*; *p<0.05, p<0.05). CONCLUSION: Spironolactone attenuated the myocardial remodelling in Chagas cardiomyopathy, reduced mortality during the chronic phase and reduced inflammatory infiltration.

Aldosterone↗

PubMed2005

[Cardiac papillary fibroelastoma. Experience of an institution].

Primary intracardiac tumors are rare, with prevalence between 0.0017% and 0.19% from non-selected autopsy studies. Approximately 75% are benign and almost half of them are myxomas. The remaining tumors are divided among rhabdomyomas, lipomas and fibroelastomas. Myxomas are the most common intracardiac tumors in adult age and rhabdomyomas the most common among pediatric population. Papillary fibroelastoma (PFE) is a relative rare benign heart tumor, corresponding to approximately 8% of intracardiac tumors. They most commonly manifested in cardiac valves. In the past, they either consisted of necropsy findings or were found in surgical procedures at random. In vivo diagnosis was sporadic. With the improvement of echocardiography techniques, PFE has been more frequently diagnosed. They are usually described as a movable, pedunculate, well-delimited mass and with predilection for valve endocardium. Therapeutic proposal, when they are pedunculate, is surgical resection, preventing cerebral, pulmonary, coronary or peripheral embolic phenomena. Five cases diagnosed in our institution, in the period from August 1995 to June 2004, will be presented.

Adult↗

PubMed2005

[Relation between left atrial dimension and exercise capacity in endomyocardial fibrosis].

OBJECTIVE: To assess whether exercise capacity is related to left atrial dimension (LAD) in patients with biventricular endomyocardial fibrosis. METHODS: This study comprised 38 patients in sinus rhythm, with a mean age of 37.5 +/- 11.5 years (range, 11 to 59 years), 25 of whom were women. They were divided into 2 groups according to the NYHA functional class on hospital admission as follows: group A (12 patients) and group B (26 patients). All patients underwent cardiopulmonary exercise testing to determine their maximum oxygen consumption (VO2 max), and their left atrial dimension was determined on echocardiography. RESULTS: The VO2max values for groups A and B were 21.8 +/- 4.8 mL.kg(-1).min(-1) and 13.7 +/- 3.5 mL.kg(-1).min(-1), respectively, and the left atrial dimensions were 3.7 +/- 0.7 cm and 4.4 +/- 0.7 cm for groups A and B, respectively. A significant and inverse correlation was found between VO2max and LAD in the groups studied. CONCLUSION: The increase in left atrial dimension is associated with impairment in exercise capacity in patients with endomyocardial fibrosis. Our findings support the use of left atrial dimension to estimate a more complex and difficult to assess index of functional capacity, such as VO2max.

Adolescent↗

PubMed2005

[Quantitative assessment of left ventricular regional wall motion in endomyocardial fibrosis].

OBJECTIVE: To analyze left ventricular (LV) regional wall motion in patients with endomyocardial fibrosis (EMF). METHODS: The study comprised 88 patients, 59 of the female sex, with a mean age of 39+/-13 years (range, 9 to 65) and with echocardiographic and angiographic evidence of left ventricular EMF. The intensity of fibrous tissue buildup on contrast cineventriculography was classified as mild, moderate, or severe. The overall left ventricular ejection fraction (LVEF) was determined by using the area-length method on ventriculography. The motion was measured in 100 equidistant chords perpendicular to the centerline drawn in the middle of the final diastolic and systolic contours and normalized to cardiac size. Five left ventricular segments were analyzed: A--apical; AL--anterolateral; AB--anterobasal; IA--inferoapical; IB--inferobasal. Abnormality was expressed in units of standard deviation of the mean motion in a normal population of reference, comprised of 103 patients with normal LV according to clinical and electrocardiographic data, and angiographic standards. RESULTS: Mean LVEF was 0.47+/-0.12. Fibrous tissue buildup in the left ventricle was mild in 12 patients, moderate in 40, and severe in 36. The regions with the poorest ventricular wall motion were A (-1.4+/-1.6 standard deviation/chords) and IA (-1.6+/-1.8 standard deviation/chords) compared with that in AB (-0.3+/-1.9 standard deviation/chords), AL (-0.5+/-1.8 standard deviation/chords) and IB (-0.9+/-1.3 standard deviation/chords). No relation was observed between the intensity of fibrous tissue buildup and regional ventricular wall motion. CONCLUSION: A change in LV regional wall motion exists in EMF, and it is independent of the intensity of fibrous tissue buildup qualitatively assessed. Nonuniform involvement of the LV should be considered when planning surgery for this disease.

Adolescent↗

PubMed2005

Benign outcome in a long-term follow-up of patients with hypertrophic cardiomyopathy in Brazil.

BACKGROUND: Selected patients with hypertrophic cardiomyopathy (HCM) have 3% to 4% annual mortality as compared to only 0.5% to 1.5% in nonselected patients. Our aim was to evaluate survival and prognostic factors in HCM in patients in a tertiary care center. METHODS: From 1980 to 1997, 214 patients were prospectively studied, with a mean follow-up of 7 years (range 1-25 years); there were 102 male and 112 female patients, aged 37 +/- 16 years (range 3-76 years). All patients had 12-lead electrocardiogram, 24-hour Holter monitor, and surface echocardiography. Univariate analysis was performed for known adverse factors such as young age, family history, syncope, functional class, atrial fibrillation, ventricular hypertrophy, left ventricular outflow tract obstruction, and nonsustained ventricular tachycardia. RESULTS: There were 22 deaths (10%), 15 directly related to HCM (sudden in 11). The cumulative survival rates were 94.5% at 5 years, 91% at 10 years, and 87.9% at 15 years. The annual mortality rate was 1%. Only New York Heart Association functional class III/IV and maximal ventricular wall thickness >30 mm were associated with HCM-related cardiac death. CONCLUSIONS: We concluded that even a referred population of HCM patients may have a relatively benign outcome. Prognosis is related to advanced functional class and degree of left ventricular hypertrophy.

Adolescent↗

PubMed2004

Left ventricular lipoma.

We report the case of a 21-year-old female referred to our institution complaining of dizziness when standing up, which improved in the dorsal decubitus position and at rest, after a few minutes. The symptom, which had lasted for years, was not accompanied by vertigo, syncope, or neurological changes, but was gradually getting worse. Transthoracic echocardiogram showed a hyperechoic mass in the middle-apical region of the left ventricular posterior wall and normal pericardium. The cardiac nuclear magnetic resonance allowed the diagnosis of the left ventricular tumor suggestive of lipoma. Surgery was performed and the tumor was resected. The patient recovered well and is currently asymptomatic.

Adult↗

PubMed2004

Quantification of Protein-Lipid Selectivity using FRET: Application to the M13 Major Coat Protein.

Quantification of lipid selectivity by membrane proteins has been previously addressed mainly from electron spin resonance studies. We present here a new methodology for quantification of protein-lipid selectivity based on fluorescence resonance energy transfer. A mutant of M13 major coat protein was labeled with 7-diethylamino-3((4'iodoacetyl)amino)phenyl-4-methylcoumarin to be used as the donor in energy transfer studies. Phospholipids labeled with N-(7-nitro-2-1,3-benzoxadiazol-4-yl) were selected as the acceptors. The dependence of protein-lipid selectivity on both hydrophobic mismatch and headgroup family was determined. M13 major coat protein exhibited larger selectivity toward phospholipids which allow for a better hydrophobic matching. Increased selectivity was also observed for anionic phospholipids and the relative association constants agreed with the ones already presented in the literature and obtained through electron spin resonance studies. This result led us to conclude that fluorescence resonance energy transfer is a promising methodology in protein-lipid selectivity studies.

Algorithms↗

PubMed2003

Right atrial lipoma.

Benign cardiac tumors are rare, and lipomas are among those less frequently found. We report the case of a 48-year-old male complaining of high blood pressure and epistaxis in the last 2 months, with a diagnosis of right atrial lipoma established on echocardiography, magnetic resonance imaging, and anatomicopathological examination. The tumor was successfully removed, and up to 42 months after surgical excision, no evidence of tumor relapse was observed.

Heart Atria↗

PubMed2003

Dependence of M13 major coat protein oligomerization and lateral segregation on bilayer composition.

M13 major coat protein was derivatized with BODIPY (n-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl iodoacetamide), and its aggregation was studied in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and DOPC/1,2-dioleoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (DOPG) or 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)/DOPG (model systems of membranes with hydrophobic thickness matching that of the protein) using photophysical methodologies (time-resolved and steady-state self-quenching, absorption, and emission spectra). It was concluded that the protein is essentially monomeric, even in the absence of anionic phospholipids. The protein was also incorporated in pure bilayers of lipids with a strong mismatch with the protein transmembrane length, 1,2-dierucoyl-sn-glycero-3-phosphocholine (DEuPC, longer lipid) and 1,2-dimyristoleoyl-sn-glycero-3-phosphocholine (DMoPC, shorter lipid), and in lipidic mixtures containing DOPC and one of these lipids. The protein was aggregated in the pure vesicles of mismatching lipid but remained essentially monomeric in the mixtures as detected from BODIPY fluorescence emission self-quenching. From fluorescence resonance energy transfer (FRET) measurements (donor-n-(iodoacetyl)aminoethyl-1-sulfonaphthylamine (IAEDANS)-labeled protein; acceptor-BODIPY labeled protein), it was concluded that in the DEuPC/DOPC and DMoPC/DOPC lipid mixtures, domains enriched in the protein and the matching lipid (DOPC) are formed.

Boron Compounds↗

PubMed2003

Cardiac remodeling in patients with systemic sclerosis with no signs or symptoms of heart failure: an endomyocardial biopsy study.

BACKGROUND: Systemic sclerosis (SSc) is a disease characterized by the fibrosis of the skin and internal organs. The nature and functional significance of myocardial damage is controversial. Systematic endomyocardial biopsy in this disease has not yet been performed. METHODS: The hypothesis that increased myocardial fibrous tissue deposition occurs in patients with systemic sclerosis with no signs or symptoms of heart failure and normal left systolic ventricle function was tested in 16 SSc patients and 10 controls. Endomyocardial biopsy specimens were obtained from the right ventricular septum in SSc patients. Myocardial specimens were obtained from the same area in controls. Masson's trichrome staining was used for collagen fiber identification. Interstitial (ICVF) and perivascular collagen volume fraction (PCVF) was quantified by videomorphometry. There was a significant increase in the ICVF in patients with SSc compared with the controls, in spite of normal systolic left ventricular function. However, it was not observed in the PCVF. CONCLUSIONS: It is possible to identify cardiac remodeling, characterized by myocardial fibrosis deposits, particularly within the interstitium in SSc patients before the any signs or symptoms of heart failure appear.

Adult↗

PubMed2002

Mitral valve replacement and remodeling of the left ventricle in dilated cardiomyopathy with mitral regurgitation: initial results.

OBJECTIVE: This study evaluated the effects of a new method of mitral valve replacement on left ventricular (LV) remodeling and heart failure functional class. METHODS: Eight patients (6 men) with severe mitral regurgitation from end-stage dilated cardiomyopathy underwent surgery. Five patients were in functional class (FC) IV, 2 were in FC III and 1 was in FC III/IV. Age ranged from 33 to 63 years. Both the anterior and posterior leaflets of the mitral valve were divided into hemileaflets. The resultant 4 pedicles were displaced under traction toward the left atrium and anchored between the mitral annulus and an implanted valvular prosthesis. The beating heart facilitated ideal chordae tendineae positioning. RESULTS: All patients survived and were discharged from the hospital. After a mean follow-up period of 6.5 months (1-12 m), 5 patients were in FC I; 2 in FC I/II; and 1 in FC II. The preoperative ejection fraction ranged from 19% to 30% (mean: 25.7 +/- 3.4 %), and the postoperative ejection fraction ranged from 21% to 40% (mean: 31.1 +/- 5.8%). Doppler echocardiography showed evidence of LV remodeling in 4 patients, including lateral wall changes and a tendency of the LV cavity to return to its elliptical shape. CONCLUSION: This technique of mitral valve replacement, involving new positioning of the chordae tendineae, allowed LV remodeling and improvement in FC during this brief follow-up period.

Adult↗