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Biomedical subjects

T Ferreira

Publications and source records attributed to T Ferreira.

At least 19 recordsLinked to original sources
PubMed2003

Narrow, duplicated internal auditory canal.

A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve.

Ear, Inner↗
PubMed2003

Effect of inhaled racemic and (R)-albuterol on airway vascular smooth muscle tone in healthy and asthmatic subjects.

Although the relative effect of racemic and (R)-albuterol on airway smooth muscle tone have been investigated in patients with airflow obstruction, the comparative effectiveness of these drugs in relaxing airway vascular smooth muscle is unknown. Therefore, we determined the actions of inhaled racemic and (R)-albuterol on airway mucosal blood flow (Qaw) normalized for anatomic dead space as an index of airway vascular smooth muscle tone in 11 healthy subjects and 10 subjects with mild asthma. We also monitored the forced expiratory volume in 1 second (FEV1) as an index of airway smooth muscle tone. Mean +/- SE baseline Qaw was 43.1 +/- 1.5 microl x min(-1) x ml(-1) in healthy subjects and 53.4 +/- 2.1 microl x min(-1) x ml(-1) in asthmatic subjects (p < 0.01). The corresponding values for FEV1 were 95.6 +/- 1.4 and 86.8 +/- 2.5% respectively, of predicted (p = 0.01). Racemic and (R)-albuterol caused a transient, dose-dependent increase of Qaw in healthy, but not in asthmatic subjects; the responses were not different between the two drugs. The FEV1 tended to increase more in asthmatics than in healthy subjects, again without a difference between the two drugs. These results show that racemic and (R)-albuterol have comparable effects on airway vascular smooth muscle and suggest that the blunted airway vascular smooth muscle response to albuterol in asthmatics is not related to (S)-albuterol.

Administration, Inhalation↗
PubMed2001

Diaphragmatic function in patients with chronic left ventricular failure.

The aim of this paper is to evaluate the function of respiratory muscles in-patients with chronic moderate left ventricular failure (LVF), and its contribution to the pathophysiology of dyspnea and fatigue. We have studied 20 male patients with LVF, classes II and III of New York Heart Association (NYHA), mean age 66.9+/-10 years (GI) and 19 male aged-matched controls without cardiopulmonary disease mean age 64.6+/-8.4 years (GII). The evaluation included (a) methods derived from volitional manoeuvres, maximal inspiratory pressures at Functional Residual Capacity; maximal expiratory pressures at total lung capacity (TLC); nasal sniff; oesophageal sniff and transdiaphragmatic pressures; (b) methods derived from non-volitional manoeuvres, using bilateral cervical magnetic stimulation of the phrenic nerves, measuring the following twitch pressures (oesophageal, gastric and the transdiaphragmatic). With volitional manoeuvres we have not found statistically significant differences between the two groups: maximal expiratory pressures (cmH(2)O), GI 138+/-42; GII 152+/-40; P=NS and maximal inspiratory pressures (cmH(2)O), GI 74.1+/-22; GII 85+/-16; P=NS. However, these values were significantly lower than those obtained with sniff manoeuvres, nasal sniff (cmH(2)O), GI 95.6+/-22; GII 99.6+/-16; P=NS and oesophageal sniff (cmH(2)O), GI 96.2+/-20; GII 97.5+/-18; P=NS. There were no significant differences between nasal sniff and oesophageal sniff. Using cervical magnetic stimulation, we also didn't find a significant difference for transdiaphragmatic twitch between groups, but the contribution of the diaphragm to the transdiaphragmatic pressure was lower in patients with LVF since the oesophageal twitch was lower (cmH(2)O), GI 11.4+/-3.4; GII 16.3+/-6.8; P<0,004. In conclusion, the contribution of the diaphragm to total ventilation in-patients with moderate LVF is preserved. However, its capacity to generate negative intra-thoracic pressures is decreased since there is a significant decrease in oesophageal twitch. So, it seems that the diaphragm is the first inspiratory muscle to be affected in patients with moderate LVF.

Journal Article↗
PubMed2001

Detection of thyroglobulin mRNA transcripts in peripheral blood of individuals with and without thyroid glands: evidence for thyroglobulin expression by blood cells.

OBJECTIVE: Recent studies have assigned clinical significance and prognostic value to the detection of thyroglobulin (Tg) mRNA in the blood of patients subjected to total thyroidectomy for a papillary or follicular thyroid carcinoma. In this study, we investigated the diagnostic specificity of Tg mRNA detection, analysing blood samples from healthy volunteers and from patients previously subjected to total thyroidectomy for reasons other than a carcinoma of the follicular epithelium. DESIGN AND METHODS: Total RNA was extracted from whole blood, reverse-transcribed and the cDNA amplified for Tg and glyceraldehyde-3-phosphate dehydrogenase with specific primers. Expression levels were analysed by using a semi-quantitative PCR. In a few cases, Lymphoprep gradients were used to separate the mononuclear and polymorphonuclear cells prior to further analysis by reverse transcription/PCR. RESULTS: Our data suggested that all individuals expressed Tg mRNA. Moreover, no differences in the expression levels between subjects with and without thyroid glands were documented. Documentation of Tg expression by the mononuclear and polymorphonuclear layers in patients without thyroid glands support the hypothesis that both lymphocytes and granulocytes express Tg and may justify a background expression in blood, independently of the presence of follicular cells in circulation. CONCLUSIONS: Tg mRNA expression is not limited to follicular cells of the thyroid gland, and its expression by normal blood cells should be considered in tests performed for diagnostic purposes.

Blood Cells↗
PubMed2001

Longitudinal left ventricular function in a population of healthy adults: a tissue Doppler imaging study.

BACKGROUND: Longitudinal left ventricular function is a major determinant of global ventricular function and is probably more sensitive than radial function in the detection of disease. Tissue Doppler imaging of the mitral annulus allows the study of longitudinal left ventricular function. METHODS: Forty-five healthy volunteers divided into two groups (younger and older than 45 years) were studied with pulsed tissue Doppler imaging of the 4 sides of the mitral annulus (septal, lateral, inferior, anterior) in 4 and 2 apical chamber views. In each wave (systolic-s, rapid filling-e, atrial contraction-a) we analyzed velocities, time intervals and velocity-time integrals, as well as heterogeneity and asynchrony indexes. Data were compared between the different sides in each group, between groups and with conventional Doppler data. RESULTS: In contrast to the septal side, the lateral side of the annulus shows higher velocities and velocity-time integrals of the s and e waves, with non-significantly shorter isovolumic relaxation time and shorter time to peak e. There is functional agreement between the lateral and inferior sides versus the septal and anterior sides of the annulus. Most systolic parameters remained unchanged with aging; however, aging was associated with decreased e velocity, increased a velocity and inverted e/a ratio. The relation between s and fractional shortening also did not change with aging. Annular isovolumic contraction time and isovolumic relaxation time were shorter than their respective global time intervals. CONCLUSIONS: This study shows that there are physiological differences in velocities, time intervals and velocity-time integrals between the 4 sides of the mitral annulus, reflecting physiological heterogeneity and asynchrony, and that some of these parameters are age dependent. These data also contribute to a better understanding of longitudinal left ventricular function and may be useful in future studies as reference values in control groups.

Adult↗
PubMed2000

Tissue Doppler imaging in different locations of the mitral annulus: all different or all the same?

BACKGROUND: The assessment of the mitral annulus motion with tissue Doppler imaging is claimed to be an accurate method to quantify global left ventricular systolic and diastolic function. However, it is not yet perfectly defined which site of the annulus must be selected. Familial amyloidotic polyneuropathy of the Portuguese type (FAP) is an hereditary systemic disease in which diastolic dysfunction may occur. AIM: 1--To determine if in FAP patients the mitral annulus motion is independent of the selected site. 2--To compare pulsed wave Doppler parameters with tissue Doppler parameters in the different annular sites. METHODS: Of 24 FAP patients studied, 14 were included. In each patient we performed conventional transmitral pulsed wave Doppler and tissue Doppler in the 4 sites of the mitral annulus and measured the velocities of the rapid filling wave e, of the atrial contraction wave a and calculated e/a ratio. RESULTS: According to the transmitral inflow profile, patients were divided in 2 groups: Group I--normal global diastolic function and Group II--abnormal relaxation. Group I--33% of these patients showed e/a > 1 in the four sites and 67% showed e/a > 1 in at least 1, but not in all the sites. The rate of normal sites per patient was 3.1. Group II--25% of these patients showed e/a < 1 in the 4 sites of the annulus and 75% had e/a < 1 in at least 1, but not in all the sites analysed. The rate of abnormal sites/patient was 3.1. in this group. When conventional and tissue Doppler data were compared (bland and altman) the septal portion of the annulus was the one with the best correlation. CONCLUSIONS: 1--The assessment of the mitral annulus motion with tissue Doppler imaging is dependent on the site selected for study. 2--The septal site was the one that showed the highest correlation and concordance between pulsed wave Doppler and tissue Doppler. 3--The relative number of normal versus abnormal sites was determinant of the transmitral pattern. 4--Tissue Doppler imaging identified: a) among patients until now classified as normal diastolic function, a subgroup of patients with abnormal function in some sites of the annulus and b) among patients with abnormal relaxation, a subgroup with normal diastolic function in some sites of the annulus.

Adult↗
PubMed2000

Tissue Doppler imaging: clinical topics for the new millenium.

INTRODUCTION: Tissue Doppler imaging is an echocardiographic technique that allows the selective visualization and quantification of myocardial signals. Its aim is to complement the conventional Doppler study, adding more and better information on specific topics of cardiovascular diseases. During the first seven years of the technique, much scientific work was produced and some clinical applications of the method have emerged. CLINICAL APPLICATIONS: I--non ischemic heart disease: The technique has been widely used in diastology, in hypertrophic cardiomyopathy, in heart transplant patients and in arrhythmology. II--ischemic heart disease: The quantitative assessment of regional diastolic and systolic function makes the technique very promising during stress echocardiography and during percutaneous transluminal coronary angioplasty. CONCLUSIONS: In 2000, tissue Doppler echocardiography is still a young, exciting and promising technique. Despite the fact that much has already been done, there is still a long way to go, implying a great amount of time and personal investment. How often do we feel that we are building a small part of the future?

Echocardiography, Doppler↗
PubMed2000

[Diastolic dysfunction and left ventricular hypertrophy in familial amyloidotic polyneuropathy: a cause-effect relationship?].

UNLABELLED: TTR Met30 Familial Amyloidotic Polyneuropathy of the Portuguese type (FAP) is an incapacitating and lethal hereditary disorder that affects predominantly young adults of both genders. Portuguese type FAP patients have sensory, motor and autonomic polyneuropathy. The generalised systemic amyloid infiltration involves the heart, leading to the characteristic granular bright sparkling echocardiographic pattern. LV wall thickening occurs in the late phases of the disease. LV diastolic dysfunction has been reported in the absence of systolic dysfunction; an abnormal diastolic transmitral flow pattern assessed by pulsed wave Doppler (PW) was described. PW is very much dependent on load conditions. Tissue Doppler imaging (TDI) has been used as a more reliable method to assess long axis diastolic function. OBJECTIVE: 1--To identify the incremental value of TDI in the assessment of diastolic function in FAP. 2--To correlate diastolic pattern abnormalities and left ventricular mass index (LVMI) in FAP patients. METHODS: We performed a prospective evaluation of 24 consecutive FAP patients and selected 14 (sinus rhythm, age < 45 years). Diastolic function was assessed by PW and classified as normal (GI-E/A > 1) or abnormal (GII-E/A < 1). TDI was performed in 4 sites of the mitral annulus (septum, lateral, inferior, anterior). Velocities of the rapid filling wave (E') and atrial contraction wave (A') were measured and E'/A' calculated. In each site we considered the TDI as normal (E'/A' > 1) or abnormal (E'/A' < 1). The LVMI was calculated by Devereux's formula. RESULTS: Age, gender and heart rate were similar in both groups. TDI at the septal mitral annulus was normal in all of the GI patients (E'/A': 1.29 +/- 0.19) and suggestive of abnormal LV relaxation in all of the GII patients (E'/A': 0.82 +/- 0.11, p < 0.0001). TDI revealed abnormal diastolic pattern when a restricted number of sites of the mitral annulus were assessed, even in GI patients and before PW abnormalities occurred. Fractional shortening (FS) and LVMI were similar in GI and GII (FS-GI: 45.5 +/- 5.3, GII 43.5 +/- 8.1%, p: NS; LVMI--GI: 66 +/- 9.3, GII: 67 +/- 3.0 g/m2 p: NS). CONCLUSION: The assessment of mitral annulus motion has introduced new data in the study of diastolic function of FAP patients. An abnormal LV relaxation pattern occurred early in the evolution of the disease in patients with normal LVMI and systolic function.

Adult↗
PubMed1999

Screening of an intragenic second-site suppressor of purine-cytosine permease from Saccharomyces cerevisiae. Possible role of Ser272 in the base translocation process.

The purine-cytosine permease from Saccharomyces cerevisiae mediates the active transport through the plasma membrane of adenine, hypoxanthine, guanine and cytosine using the proton electrochemical potential difference as an energy source. Analysis of the activity of strains mutated in a hydrophilic segment (371-377) of the polypeptidic chain has shown the involvement of this segment in the maintenance of the active three-dimensional structure of the carrier. In an attempt to identify permease domains that could interact functionally and/or physically with this segment, we looked for second-site mutations that could suppress the effects of amino acid changes in this region. This paper describes a positive screen that has allowed the isolation of one suppressor from a permease mutant displaying the N374I change (fcy2-20 allele), a substitution that induces a dramatic decrease in the affinity of the carrier for adenine, cytosine and hypoxanthine. The second-site mutation corresponds to the replacement of the Ser272 residue by Leu. Its suppressive effect is shown to be a partial restoration of the binding of cytosine and hypoxanthine to the permease. To test whether this second-site mutation is specific for the fcy2-20 allele, two double mutants were constructed (Fcy2pT213I, S272L and Fcy2pS272L, N377G). Results obtained with these two double mutants showed that the suppressive effect of S272 L replacement was not specific for the original N374I change. To understand the general effect of this amino acid replacement for the three distinct double mutants, a strain overexpressing Fcy2pS272I, was constructed. Kinetic analysis of this strain showed that, by itself, the S272 L change induced an improvement in the base-binding step that could account for its global suppressive effect. Moreover, S272 L induced a decrease in the turnover of the permease, thus showing the involvement of S272 in the translocation process. Taking into account the topological model of the permease proposed here, this Ser residue is probably located in a transmembrane amphipathic alpha-helix (TM5). The location and the observed decrease in the turnover of the carrier observed with the S272 L change lead us to propose that S272 could be part of a hydrophilic pore involved in the translocation of the base and/or the proton.

Adenine↗
PubMed1999

Evidence for a dynamic role for proline376 in the purine-cytosine permease of Saccharomyces cerevisiae.

The purine-cytosine permease (PCP), a carrier located in the plasma membrane of Saccharomyces cerevisiae, mediates the active transport of purine (adenine, guanine and hypoxanthine) and cytosine into the cell. Previous studies [Ferreira, T, Brèthes, D., Pinson, B., Napias, C. & Chevallier, J. et al. (1997) J. Biol. Chem. 272, 9697-9702] suggest that the hydrophilic segment 371-377 (-I-A-N-N-I-P-N-) of the polypeptide chain may play a key role in the correct three-dimensional structure of the active carrier. This paper describes the effects of mutations in this particular segment: a four-residue deletion, Delta374-377, and two substitutions, P376G and P376R. The Delta374-377 PCP was expressed in tiny amounts and was totally inactive. When compared with the wild-type, the P376G PCP showed slightly decreased amounts and was able to transport the bases with significantly increased affinity and decreased turnover. The P376R PCP was normally expressed and targeted to the plasma membrane; however, despite a normal number of base-binding sites [1000-1200 pmol.(mg protein)-1], this mutated carrier was completely unable to transport any of its ligands. In addition, the Kd(app) for hypoxanthine binding was completely independent of the pH (within the range 3.5-6.0), showing that the conformational change induced by ligand binding was no longer present. Our results show that the 374-377 segment is essential for the expression and activity of this carrier. They also show that the P376 residue is part of an unusual secondary structure, probably a beta-turn motif, which must play a crucial dynamic role in the translocation process.

Adenine↗
PubMed1999

Pulmonary artery fibrous bands: report of a case with extensive lung infarction and superinfection with Coccidioides immitis, Pseudomonas, and acid-fast bacilli.

A 46-year-old woman presented with shortness of breath and frequent lower respiratory tract infections. A ventilation-perfusion scan showed markedly reduced perfusion of the right lung, and pulmonary arteriogram showed stenosis of the right pulmonary artery. A right pneumonectomy revealed dense white fibrous bands partially occluding the pulmonary artery branches and two large abscess cavities filled with pus in the upper and lower lobes. Microscopic examination revealed extensive necrosis of lung parenchyma, suppurative granulomatous inflammation with Coccidioides immitis organisms and rare acid-fast bacilli. Pulmonary artery fibrous bands were originally believed to be congenital; however, they are now known to be sequelae of thromboembolic phenomena.

Coccidioides↗
PubMed1998

Skin wounds. Assessment and care.

The primary goal of any skin care program should be prevention of breakdown. Unfortunately, that goal is not always achievable. As our bodies age or when they become immunosuppressed, incontinent, malnourished, underhydrated, immobile or simply fragile, our skin is less able to preserve its integrity or heal on its own.

Bandages↗
PubMed1998

[Aortic peri-valvular abscess, mycotic aneurysm of Valsalva sinus, and fistula to the right ventricle in a context of acute infectious endocarditis].

Infective endocarditis continues to attract the attention of many physicians. The authors present a case report of a 64 year old man with a history of infective endocarditis of a native aortic valve complicated by a perivalvular abscess, mycotic aneurysm of a sinus of valsalva and acquired aorta-right ventricular shunt.

Aneurysm, Infected↗