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Biomedical subjects

M Gonçalves

Publications and source records attributed to M Gonçalves.

At least 19 recordsLinked to original sources
PubMed2006

Effect of electrochemical treatment of oleic acid on anaerobic digestion.

Electrochemical pre-treatment of oleate on anaerobic digestion was investigated using two anaerobic filters (AF and AFm) working, respectively, with increasing concentrations of electrochemically pre-treated oleate and oleate. Influents containing 25% and 50% of chemical oxygen demand (COD) of these substrates did not cause relevant alterations in either digester's performance. Comparatively, the pre-treated oleate unit (AF) showed a higher gas production but a lower COD removal than AFm (2.0 vs 1.5 m(3) CH4 m(-3) d(-1) 76-85 vs 91-93% COD removal). The raised AFm COD removal together with the larger proportion of VSS in its effluent than in AF (5.69 vs 0.26 kg m(-3)) indicate that the biomass washout can be a consequence of the encapsulated solids by lipidic compounds that were not fairly degraded. Further increases of oleate in AFm feed (75 and 100% COD) led to decreases of biogas production to half and COD removal from values higher than 90% to 83-75%. The simultaneous increase of effluent VSS concentrations to 10-12 kg m(3) emphasizes the oleate negative effect. The use of pretreated oleate as the only carbon source did not influence negatively the AF behaviour in terms of methane production. COD removal was maintained at values higher than 80% and the effluent VSS at low concentrations (0.15 kg m(-3)). The significantly higher methane yield achieved by AF than AFm indicates a higher accumulation of oleate than pre-treated oleate. Therefore, electrochemical process stands for a suitable pre-treatment for lipid rich effluents, allowing the application of higher organic loads keeping a higher methane yield.

Anaerobiosis↗
PubMed2005

Electromyographic validation of the pectoralis major and deltoideus anterior muscles in inverted "flying" exercises with loads.

Inverted 'flying" exercise with external loads of 25, 50, 75 and 100% of each individual maximum load in the pectoralis major and deltoideus anterior muscles was electromyographically analyzed in eleven male volunteers, using surface electrodes MEDI-TRACE-200 connected to a biological signals acquisition module coupled to a PC/AT computer. Electromyographic signals were processed and the effective values obtained were standardized through maximum voluntary isometric contraction. When the concentric phase of each muscle with the same load was statistically compared with the eccentric phase, it was observed that for all loads all the muscles presented significant electromyographic difference, and that the concentric phase was always higher. By analyzing the different loads for each muscle, it was noticed that in the concentric phase all the muscles presented significant electromyographic activity, being it higher with maximum load. When the effect of each load on different muscle in the concentric and eccentric phases was analyzed, the muscles presented a distinct activity profile.

Adolescent↗
PubMed2004

Effect of the aerobic capacity on the validity of the anaerobic threshold for determination of the maximal lactate steady state in cycling.

The maximal lactate steady state (MLSS) is the highest blood lactate concentration that can be identified as maintaining a steady state during a prolonged submaximal constant workload. The objective of the present study was to analyze the influence of the aerobic capacity on the validity of anaerobic threshold (AT) to estimate the exercise intensity at MLSS (MLSS intensity) during cycling. Ten untrained males (UC) and 9 male endurance cyclists (EC) matched for age, weight and height performed one incremental maximal load test to determine AT and two to four 30-min constant submaximal load tests on a mechanically braked cycle ergometer to determine MLSS and MLSS intensity. AT was determined as the intensity corresponding to 3.5 mM blood lactate. MLSS intensity was defined as the highest workload at which blood lactate concentration did not increase by more than 1 mM between minutes 10 and 30 of the constant workload. MLSS intensity (EC = 282.1 +/- 23.8 W; UC = 180.2 +/- 24.5 W) and AT (EC = 274.8 +/- 24.9 W; UC = 187.2 +/- 28.0 W) were significantly higher in trained group. However, there was no significant difference in MLSS between EC (5.0 +/- 1.2 mM) and UC (4.9 +/- 1.7 mM). The MLSS intensity and AT were not different and significantly correlated in both groups (EC: r = 0.77; UC: r = 0.81). We conclude that MLSS and the validity of AT to estimate MLSS intensity during cycling, analyzed in a cross-sectional design (trained x sedentary), do not depend on the aerobic capacity.

Anaerobic Threshold↗
PubMed2004

Spectral analysis of the electromyograph of the erector spinae muscle before and after a dynamic manual load-lifting test.

The aim of the present study was to assess the spectral behavior of the erector spinae muscle during isometric contractions performed before and after a dynamic manual load-lifting test carried out by the trunk in order to determine the capacity of muscle to perform this task. Nine healthy female students participated in the experiment. Their average age, height, and body mass (+/- SD) were 20 +/- 1 years, 1.6 +/- 0.03 m, and 53 +/- 4 kg, respectively. The development of muscle fatigue was assessed by spectral analysis (median frequency) and root mean square with time. The test consisted of repeated bending movements from the trunk, starting from a 45 masculine angle of flexion, with the application of approximately 15, 25 and 50% of maximum individual load, to the stand up position. The protocol used proved to be more reliable with loads exceeding 50% of the maximum for the identification of muscle fatigue by electromyography as a function of time. Most of the volunteers showed an increase in root mean square versus time on both the right (N = 7) and the left (N = 6) side, indicating a tendency to become fatigued. With respect to the changes in median frequency of the electromyographic signal, the loads used in this study had no significant effect on either the right or the left side of the erector spinae muscle at this frequency, suggesting that a higher amount and percentage of loads would produce more substantial results in the study of isotonic contractions.

Adult↗
PubMed2003

Electromyographic fatigue threshold of erector spinae muscle induced by a muscular endurance test in health men.

PURPOSE: To identify the electromyographic fatigue threshold in the erector spinae muscle. METHODS: Eight 19 to 24-year-old male volunteers participated in this study, in which surface electrodes were used, as well as a biological signals acquisition module (Lynx) with a sampling frequency of 1000 Hz, a 1000 times gain, a 20 Hz high pass filter and a 500 Hz low pass filter. The test consisted of repeated isometric contractions of the erector spinae muscle in a 45 degrees hip flexion posture, with 30%, 40%, 50% and 60% of the maximum voluntary isometric contraction. RESULTS: A positive correlation of the RMS (root mean square) value as a function of time was found for most of the subjects with 40% (N = 6), 50% (N = 7) and 60% (N = 8) loads of the maximum voluntary isometric contraction. CONCLUSIONS: It was concluded, from this study, that the proposed protocol provides evidence, through the electromyographic signal, of the development of fatigue in the erector spinae muscle with loads of 40%, 50% and 60% of the maximum voluntary isometric contraction. The protocol also allows the electromyographic fatigue threshold and its probable applicability in the diagnosis of this phenomenon during repetitive activities to be determined.

Adult↗
PubMed2003

Electromyographic analysis of the arm muscles in "front support" exercises.

The electromyographic activity of the biceps brachii--BB (long head), triceps brachii--TB (long head) and deltoideus--DA (clavicular portion) muscles, during the going (G) and return (R) phases in "front support" exercise, as well the efficacy of this exercise for the development of these muscles strength were studied in 10 male volunteers. The values were normalized through maximum voluntary isometric contraction (MVIC = 100%) and statistically analyzed using the Friedman, DMS and Wilcoxon non-parametric test. A value of p < or = 0.05 indicated significance (Campos, 1983). All the muscles presented higher electromyographic activity in the return phase of the movement. The triceps brachii was the muscle which had higher activity in both phases of the movement. It was concluded that the "front support" exercise is efficient for strength development mainly in the triceps brachii muscle.

Adolescent↗
PubMed2002

Dens invaginatus type III: report of a case and 10-year radiographic follow-up.

AIM: The purpose of this article is to report the 10-year follow-up of a right mandibular central incisor with 'dens invaginatus' that was root filled. SUMMARY: 'Dens invaginatus' is a rare malformation of teeth, probably resulting from an infolding of the dental papilla during tooth development. It has alternatively been called 'dens in dente' and 'dilated composite odontome'. Radiographic examination may clearly demonstrate this feature, although no signs may be recognized clinically. If no entrance to the invagination can be detected and there are no signs of pulp pathosis, then no treatment is required other than fissure sealing of the invagination. In deep invaginations, it is likely that root-canal treatment may be required. Occasionally, when the tooth has an immature root, apexification is necessary. Root-canal treatment of a right mandibular central incisor with 'dens invaginatus' is described along with 10-year follow-up. KEY LEARNING POINTS: Both clinical and radiographic examinations are necessary to determine morphological features of teeth before root-canal treatment. Sensibility testing to determine the pulp condition is critical prior to treatment.

Child↗
PubMed2002

Electromyographic validation of the double pulley equipment during movements of the lower limbs.

The double pulley equipment was tested on ten male volunteers during contraction of the semitendinosus and biceps femoris (caput longum) muscles in the following movements of the lower limbs: 1) hip extension with extended knee and erect trunk, 2) hip extension with flexed knee and erect trunk, 3) hip extension with flexed knee and erect trunk, 3) hip extension with extended knee and inclined trunk, 5) hip abduction along the midline, 7) hip abduction with extension beyond the midline, 8) adduction with hip flexion beyond the midline, 8) adduction with hip flexion beyond the midline, and 9) adduction with hip extension beyond the midline. The myoelectric signals were taken up by Lec Tec surface electrodes connected to a 6-channel Lynx electromyographic signal amplifier coupled with a computer equipped with a model CAD 10/26 analogue digital conversion board and with a specific software for signal recording and analysis. The semitendinosus and biceps femoris muscles presented the highest potentials in movements 1; 2; 7, 8 and 9, whereas the potentials in the remaining movements were negligible. The pattern of activity of the semitendinosus and the biceps femoris was similar in exercises 1, 2, 3, 4 and 8. The potentials of the semitendinosus prevailed in movements 5, 6 and 7, and the strongest potentials observed in movement 9 were those of the biceps femoris.

Adolescent↗
PubMed2000

[Clinical correlation of angiographic restenosis, isolated or associated with stress test variables, with a population that had stent implantation].

OBJECTIVE: We analyse the value of the clinical data, isolated or associated with the stress EKG (SEKG) variables, in the detection of angiographic restenosis (AR: lesion > 50%), in a group of patients (pts) submitted to coronary angioplasty (PTCA) with stenting. POPULATION AND METHODS: 105 patients were followed prospectively (male: 87%; age: 56 +/- 10); clinical evaluation was performed in the 1st, 3rd and 6th month, SEKG in the 4th month and recatheterization for angiographic control in the 6th month. The vascular risk factors, cause of admission, medication at discharge, angiographic and procedure characteristics were analysed. RESULTS: The most frequent vascular risk factors were hypertension (42%), smoking (64%), and dyslipidemia (52%); 30% had previous ischemic heart disease. The indication for PTCA was myocardial infarction (direct PTCA or residual ischemia) in 42% and angina in 59%. All patients were discharged with AAS and ticlopidine, 38% with beta-blockers, 59% with calcium channel blockers and 92% with nitrates. Thirty-eight percent had multivessel disease. They were submitted to dilatation with the implantation of 128 stents in 199 vessels. An intraaortic balloon pump was used in 13% and Abciximab in 47% of the procedures. In the recatheterization for angiographic control in the sixth month, 30 patients had angiographic restenosis (AR rate = 25.2%). In the clinical evaluation, 22 patients (20.9%) had angina, and 14 of them had angiographic restenosis (clinical restenosis rate = 13.3%). In the 16 asymptomatic patients with AR, 5 had positive SEKG. CONCLUSION: The presence of angina in a group of patients submitted to coronary angioplasty with stenting has a low sensitivity (54%), a good specificity (88%), a positive predictive value of 64% and negative of 83% in the detection of angiographic restenosis. The association with clinical data improves sensitivity (83%), with a decrease in specificity (61%).

Aged↗
PubMed2000

Primary angioplasty for acute myocardial infarction complicated by cardiogenic shock on admission.

AIM: To evaluate primary angioplasty results for the treatment of acute myocardial infarction complicated by cardiogenic shock on admission. POPULATION AND METHODS: Retrospective analysis of 11 consecutive patients with acute myocardial infarction complicated by cardiogenic shock (defined as systolic blood pressure below 80 mmHg and signs of hypoperfusion, despite volume expanders and/or vasopressors infusion) treated with primary angioplasty. Clinical characteristics, angiographic data, hospital outcome and follow-up were analysed. RESULTS: There were ten males (90.9%) with a mean age of 66 years. Eight patients had anterior wall myocardial infarction and three patients had inferior wall myocardial infarction, two of which with extension to the right ventricle. The mean time between symptom onset and angioplasty was 3.5 hours. Three patients had left main coronary artery occlusion; three patients had single vessel disease and five patients had multivessel disease. The angiographic success rate (open infarct-related artery and TIMI III flow) was 90.9% (ten patients). Stent implantation was performed in five patients. Abciximab was given in five patients. In-hospital mortality rate was 36.4% (four patients). The surviving patients had a mean ejection fraction of 43.1% on discharge. In a mean follow-up of 16.2 months, one patient had coronary artery bypass graft and one had stroke. CONCLUSION: Based on published data, our experience with this short series of cases shows that primary angiography should be regarded as a positive option for the treatment of acute myocardial infarction complicated by cardiogenic shock.

Aged↗
PubMed1999

Electromyographic behaviour of the gastrocnemius muscle during knee extension and flexion performed on the leg press.

The gastrocnemius was analysed in 10 male volunteers during knee flexion and extension with the foot in normal, plantar flexion and dorsal flexion positions. Hewlett-Packard surface electrodes, an electromyographic signal amplifier, a computer equipped with an A/D conversion plaque (Model CAD 10/26), a software specially designed to record and analyse the signals, a horizontal leg press, and electrogoniometers were used. The gastrocnemius muscle showed strong potentials at the end of knee extension and beginning of knee flexion. The muscle presented a similar activity both in the upper and lower platforms. As to bilateral action, the right gastrocnemius presented stronger potentials on the upper platforms, whereas the potentials were bilaterally similar on the lower platforms. As for foot position, the gastrocnemius presented strong potentials when the foot was in plantar flexion. The remaining positions had no effect on the work of the muscle.

Adult↗
PubMed1999

[Angioplasty with stenting in single vessel disease: non invasive methods for detecting restenosis].

OBJECTIVE: To compare the value of the myocardial perfusion imaging with 99Tc sestamibi (MIBI) with clinical data and stress EKG (SEKG) variables, in the detection of angiographic restenosis (AR: lesion > 50%), in a group of patients (pts) with single vessel disease (angiographic lesion above 70% in one epicardial artery), submitted to coronary angioplasty (PTCA) with stenting. POPULATION AND METHODS: Fifty-nine pts, followed prospectively, (49 males and 10 females aged 57 +/- 10) were submitted to 61 angioplasties, with dilatation of 59 vessels, and with stenting in 63 (1.07 stent/vessel). Clinical evaluation was performed in the first, third and sixth month, SEKG with MIBI in the fourth month and recatheterization for angiographic control in the sixth month. The pts were divided in two groups: R-positive angiographic restenosis (AR)--14 pts: NR--without AR--45 pts; the angiographic restenosis rate was 23.7%. The patients' history, cause of admission, procedure characteristics, medication at discharge, clinical events during follow-up, variables of stress EKG associated with myocardial perfusion and angiographic control were analyzed. RESULTS: The cause of admission was the same in both groups (MI in R group: 28.6%; NR: 46.7%; p = ns). There was no difference in the discharge medication. The R group was more symptomatic (Angina: R = 50.0% vs NR = 11.1%; p < 0.001 clinical restenosis rate = 11.8%), and had more revascularization procedures (PTCA: R = 57.1% vs NR = 2.8%; p < 0.001/Bypass surgery: R = 14.3% vs NR = 0%; p = 0.01). This group had abnormal stress EKG more frequently (42.9 vs 20.0%, p = ns) and ischemia in the myocardial perfusion scintigraphy (57.1 vs 6.7% p < 0.001). [table: see text] CONCLUSION: The clinical and diagnostic tests evaluated in this study showed a limited sensitivity in the detection of angiographic restenosis in a group of patients with single vessel disease submitted to coronary angioplasty and stenting. Myocardial scintigraphy was the best method for the detection of angiographic restenosis, showing a high specificity and a reasonable sensitivity.

Angioplasty↗
PubMed1999

[Evaluation of the prognostic value of cardiac troponin i in patients with unstable angina].

OBJECTIVE: The purpose of this study was to evaluate the in-hospital and follow-up prognostic value of cardiac troponin I in patients admitted in the Coronary Care Unit and discharged with the diagnosis of unstable angina. POPULATION AND METHODS: 118 patients were admitted in the Coronary Care Unit, discharged with the diagnosis of unstable angina with a follow-up of 13.5 months. Cardiac Troponin I (cTnI) was measured on admission, 4 and 12 hours later. For the purposes of the study, we chose a cut-off value of 0.4 ng/mL as the minimal acceptable concentration of cTnI. The patients were divided in two groups: Group A (n = 82) if all measurements with cTnI < or = 0.4 ng/mL and Group B (n = 36) if any measurement with cTnI > 0.4 ng/mL. In both groups, multiple coronary events during hospitalisation and follow-up were evaluated: death; acute myocardial infarction; angina; hospitalisation; coronary surgery or angioplasty; and also the severity of coronary artery disease and the number of patients without coronary events. The results were compared by the Student's unpaired t-test and by chi-square test. RESULTS: Age, sex and vascular risk factors were similar in both groups. There was a statistically significant increase in angina and coronary surgery with increasing levels of cardiac troponin I (Group B) (13 vs 5, p < 0.0001), multiple vessel disease (16 vs 18, p < 0.0008) and myocardial infarction (12% vs 0%, p < 0.03). Sixty patients had no coronary events in Group A compared to thirteen in Group B (p < 0.0001). There were no significant differences between the groups with respect to hospitalisation and angioplasty (17% in Group B vs 7% in Group A) and death (3% vs 0%). CONCLUSIONS: In this population with unstable angina, cardiac troponin I level greater than 0.4 ng/mL measured in the 12 hours after admission provides useful prognostic information. It permits the early identification of patients with an increased risk of in-hospital and follow-up cardiac events and could be correlated with the severity of coronary artery disease.

Angina, Unstable↗
PubMed1999

[Serum markers for ischemic myocardial damage].

Assays of serum enzymes, such as aspartate aminotransferase (AST), lactate dehydrogenase (LDH), creatine kinase (CK) and isoenzyme MB, are widely performed in the early phase of suspected ischemic myocardial injury. However, these enzymes are not restricted to cardiac muscle tissue and increases in their serum concentrations have been observed in non-cardiac conditions. The levels of CK, and especially those of the myocardial specific isoform (CK-MB), have served as essential components for clinical decision in emergency rooms for over 25 years. This standard diagnostic test is far from perfect in specificity and the time delay necessary for the detection of a rise in levels. The clinician needs specific and sensitive biological parameters that can be rapidly measured in serum immediately after ischemic damage. In the last years, several new serum markers of myocardial damage have been developed. Currently, an important place is reserved for some non-enzyme muscle constituents, such as myoglobin and troponin sub-units, which have better specificity and allow an earlier detection of myocardial damage. The immunoassay of human cardiac troponin is a specific and sensitive diagnostic method for acute and sub-acute myocardial damage. It is ideal for the detection of myocardial necrosis in complex clinical situations when the usual enzymatic markers may be ineffective. An important prognostic value of troponin levels, especially troponin T, is currently under investigation. Myoglobin is a protein with low molecular weight that is abnormally high in serum two hours after myocardial infarction. Despite their high sensitivity, the use of serum measurements in the emergency room is controversial because of their low specificity, requiring the exclusion of skeletal muscle damage. Sensitivity could be lost in patients with renal function damage. The measurement of CK-MB protein weight (CK-MBmass) is another marker that has been confirmed as more accurate than CK-MB activity assays, especially in patients presented within four hours after the onset of chest pain, but could be inaccurate in several circumstances. In this research article, the authors describe the most important parameters of enzymatic and non-enzymatic markers, the kinetics of serum release, the clinical applications and the problems.

Aspartate Aminotransferases↗
PubMed1998

Two-year follow-up study of elderly residents in S. Paulo, Brazil: methodology and preliminary results.

INTRODUCTION: Previous cross-sectional studies have shown a high prevalence of chronic disease and disability among the elderly. Given Brazil's rapid aging process and the obvious consequences of the growing number of old people with chronic diseases and associated disabilities for the provision of health services, a need was felt for a study that would overcome the limitations of cross-sectional data and shed some light on the main factors determining whether a person will live longer and free of disabling diseases, the so-called successful aging. The methodology of the first follow-up study of elderly residents in Brazil is presented. METHOD: The profile of the initial cohort is compared with previous cross-sectional data and an in-depth analysis of nonresponse is carried out in order to assess the validity of future longitudinal analysis. The EPIDOSO ('Epidemiologia do Idoso') Study conducted a two-year follow-up of 1,667 elderly people (65+), living in S. Paulo. The study consisted of two waves, each consisting of household, clinical, and biochemical surveys. RESULTS AND CONCLUSIONS: In general, the initial cohort showed a similar profile to previous cross-sectional samples in S. Paulo. There was a majority of women, mostly widows, living in multigenerational households, and a high prevalence of chronic illnesses, psychiatric disturbances, and physical disabilities. Despite all the difficulties inherent in follow-up studies, there was a fairly low rate of nonresponse to the household survey after two years, which did not actually affect the representation of the cohort at the final household assessment, making unbiased longitudinal analysis possible. Concerning the clinical and blood sampling surveys, the respondents tended to be younger and less disabled than the nonrespondents, limiting the use of the clinical and laboratory data to longitudinal analysis aimed at a healthier cohort. It is worth mentioning that gender, education, family support, and socioeconomic status were not important determinants of nonresponse, as is often the case.

Aged↗
PubMed1998

[Congenital bronchopulmonary cystic disease].

From September 1989 to December 1994, 12 children with congenital bronchopulmonary cystic disease were operated in the Department of Pediatric Surgery, Santa Maria Hospital. Four cases of bronchogenic cyst (BC), 2 of cystic adenomatoid malformation (CAM), 3 of pulmonary sequestration (PS), and 3 of congenital lobar emphysema (CLE) were found. Age ranged between 9 days and 10 years without predominance of gender. Seven were younger than one year of age, of which 5 were less than 6 months old at the time of surgery. The CAT scan was most useful in the diagnosis and follow-up of these children. The review of these cases helped evaluate our experience in the diagnosis and surgical approach for these congenital malformations. Successful treatment depends on early diagnosis and the planning of therapeutic priorities, based on the embryological and pathophysiological knowledge at these anomalies. The embryological mechanisms implicated in the development are discussed and the results of surgical treatment are presented.

Bronchogenic Cyst↗