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Biomedical subjects

H Pereira

Publications and source records attributed to H Pereira.

At least 37 records · Page 2Linked to original sources
PubMed1998

Comparative kinetics of bloodmeal intake by Triatoma infestans and Rhodnius prolixus, the two principal vectors of Chagas disease.

Chagas disease vector insects Triatoma infestans and Rhodnius prolixus (fifteen stage III nymphs per 4 litre cage) were allowed to feed on anaesthetized mice for 1 h (control group), or on active non-anaesthetized mice (NAM) for 2, 4 or 8 h exposure. The bloodmeal size (weight increase) for both species was proportional to the duration of contact with NAM, due to ingestion of multiple small bloodmeals, up to 142% of control weight for T. infestans with 8 h exposure to NAM. The mean weight increase of T. infestans nymphs after 4 h contact with NAM was similar to that of the control group, whereas for R. prolixus, 8 h contact with NAM gave only 64% of the control value. For both species of insect, within 4 h of feeding, > 20% of the bloodmeal weight was lost by defaecation and diuresis. The proportions of unfed nymphs and mortality during 2 h contact with NAM were significantly higher for R. prolixus, demonstrating better exploitation of the host blood source by T. infestans, apparently because during blood-feeding the latter insect species caused less irritation to the host.

Animals↗
PubMed1998

[Facial paralysis. Neuro-muscular reconstruction techniques].

Several surgical procedures have been proposed through the years for the treatment of facial paralysis. The multiplicity and diversity of techniques portray the complexity and challenge represented by this pathology. Two basic dynamic options are available: -Reconstruction of nerve continuity through direct micro suture, with interposition grafts or nerve transpositions. -Regional muscular transposition, most often using the temporalis. Facial reanimation with the temporalis transfer has withstood the test of time and still is a reference technique. In a few weeks, good results can be obtained with a single and rather simple surgical procedure. Functional free flaps have been used with increasing frequency in the last two decades, most often combining a cross-facial nerve graft followed by a gracilis free flap nine months later. With this method there is a potential for restoration of spontaneous facial mimetic function. Apparently there is a limit in microsurgical technique and expertise beyond which there is no clear improvement in nerve regeneration. Current research is now actively studying and identifying nerve growth factors and pharmacological agents that might have an important and complementary role in the near future.

Facial Muscles↗
PubMed1998

[Direct coronary angioplasty versus thrombolysis in the acute phase of myocardial infarction--inpatient outcome].

Both thrombolysis and percutaneous transluminal coronary angioplasty (PTCA) are effective methods for the treatment of acute myocardial infarction (AMI). In our centre we perform primary PTCA during the available schedule of the hemodynamics laboratory. In this article we compare the predischarge evolution of patients submitted to each therapeutic procedure. From January 1996 to June 1997, 298 patients were admitted with the diagnosis of AMI. Eighty-four patients (28%) were thrombolysed (TB group) and 30 patients (10%) underwent primary PTCA (PTCA group). There were no significant differences among the two groups concerning demographic characteristics: age (61 +/- 13--TB and 59 +/- 12 years--PTCA); sex (male 81%--TB; 83%--PTCA), risk factors and previous cardiac history. The mean time since the onset of symptoms until arrival at the hospital was 156 +/- 156 minutes for TB and 202 +/- 210 minutes for PTCA (p < 0.02). The delay since admission until the beginning of treatment was 100 +/- 88 minutes for TB and 119 +/- 142 minutes for PTCA. The primary success rate of PTCA was 94% and there were no complications during the procedure. During the hospital stay, 12 patients developed post-infarction angina in the TB group and two patients in the PTCA group; in 15 patients of the TB group a revascularization procedure was performed (surgery in 5 and PTCA in 10 patients); one patient suffered reinfarction in the TB group. Two patients of the TB group (2.4%) had intracranial hemorrhage; the in-hospital mortality was 9.5% in the TB group and 3.3% in the PTCA (p < 0.001). The mean in-hospital stay was 11 +/- 5.6 in the TB group and 7.8 +/- 2.5 days in the PTCA group (p = 0.055). In our experience, primary PTCA in AMI appeared to be a safe procedure with lower occurrence of coronary events and hemorrhagic complication, with an earlier hospital discharge when compared to thrombolysis.

Adult↗
PubMed1998

[Is the stress test useful in the detection of post-angioplasty restenosis?].

Restetenosis is still the greatest limitation of coronary angioplasty (PTCA). The systematic use of ergometry (PE) with the objective of identifying restenosis is controversial and, namely, the ACC/AHA does not recommend its routine use. Our objective was to conduct a retrospective study of the use of PE when performed late (3 to 6 months) for the detection of restenosis. As a protocol, our group performed "late" PE on all the patients without contraindications, the patients with positive ergometry or CCS class II-IV angor submitted to angiographic control. Between January 1996 and July 1997, 121 patients (pts) were submitted to PTCA. Our study population was composed of patients submitted to complete revascularisation with follow-up in our centre: 59 pts (49%) with an average age of 58 +/- 12 years, 82% male. Eighty-three percent of the pts had revascularisation in a context of unstable angina, 10% in the acute phase of myocardial infarction and 7% due to chronic angina. Stents were implanted in 42% of the pts. In the follow-up after six months, 7 pts complained of CCS class II or III angor. The ergometry showed positive electrocardiographic criteria in 11 pts (18.6%). All pts with angor had positive PE. All these pts were submitted to angiographic control; restenosis (residual stenosis equal to or above 50%) was observed in all the patients who complained of angor (100% positive predictive value); restenosis occurred in 9 pts with positive ergometry (82% positive predictive value). In asymptomatic pts, PE indicated 2 pts with restenosis (2/59-3.4%) and two false positive (2/11-18%). At six months, PE detected 22% of the pts with restenosis. In conclusion, complete post-revascularisation angor due to coronary angioplasty has a higher positive predictive value than ergometry. However, the stress test, performed systematically, can identify an additional percentage of pts with restenosis with an acceptable percentage of false positives.

Angioplasty, Balloon, Coronary↗
PubMed1998

[Abciximab (ReoPro) in primary angioplasty].

UNLABELLED: The aim of the study was to evaluate the efficacy and safety of abciximab (ReoPro) in primary percutaneous transluminal coronary angioplasty (P.T.C.A.) in patients with myocardial infarction (M.I.). From June 96 to October 97, 16 patients with a mean age of 58 +/- 12 years, 86% males, with myocardial infarction (less than 12 hours of pain) were treated with ReoPro during P.T.C.A. The infarction was anterior in seven patients (44%), inferior in eight patients (50%) and non-Q wave in one patient (6%). Nine patients (47%) had a previous history of angina or myocardial infarction. The mean time from onset of symptoms to hospital arrival was 306 +/- 370 min and the mean time between hospital admission and the beginning of the procedure was 79 +/- 86 min. P.T.C.A. was performed on the anterior descending artery and right coronary in 44% and 56%, respectively. The success rate was 94%. Stents were used in 31%. In patients with angiographic success, we obtained TIMI III flow in 14 patients and TIMI II in one patient. No complications arose during P.C.T.A; no significant changes in platelets or hemoglobin were observed after the procedure. In this group of patients, one case of hematoma was found at the site of puncture with no need for transfusion. During hospitalization, no major coronary events were found. During the follow-up of 10.5 +/- 4.9 months, one patient died after non cardiac surgery and one patient was submitted to coronary artery bypass graft; there was no reinfarction nor new P.T.C.A. CONCLUSIONS: In our experience with ReoPro during direct angioplasty, we obtained good immediate and long term results, with no significant bleeding complications.

Abciximab↗
PubMed1997

Prognostic markers for colorectal cancer: expression of P53 and BCL2.

P53 is a tumor suppressor gene that has been implicated in the pathogenesis of a wide range of tumor types including colorectal cancers. bcl2 is a proto-oncogene that inhibits apoptosis. Immunostaining for P53 and BLC2 protein product was performed in a retrospective series of 80 colorectal carcinomas with a minimum follow-up of 5 years. The aim of the study was to evaluate the prognostic significance of P53 and BCL2 protein expression and their correlation with clinicopathologic variables such as pathologic disease stage (Dukes system), histologic grade, and vascular invasion. The patients were 41 to 76 years of age, and the follow-up ranged between 5 and 10 years. Among the 80 cases, 30 were Dukes stage A and 50 stage B. We found vascular invasion in 21.2%. P53 and BCL2 expression was detected, respectively, in 30.0% and 8.8%. We concluded that the P53 and BCL2 expression detected by immunohistochemistry in routinely processed, paraffin-embedded tissues: (1) has no prognostic significance; and (2) was not correlated with pathologic disease stage, histologic grade, or vascular invasion. Nevertheless, the number of patients in our study was small, and we believe that investigation of a larger series of patients is indicated.

Adult↗
PubMed1995

Metallothionein expression in human breast cancer.

Metallothioneins are ubiquitous low molecular weight proteins characterised by high cysteine content and affinity for binding heavy metals. Abnormal metallothionein function and expression have been implicated in various disease states, including neoplasia. The aim of this study was to investigate metallothionein expression in human breast carcinoma. Sections of routinely fixed and processed blocks of tumour from 100 consecutive cases of primary operable breast carcinoma were stained for metallothionein using a recently developed monoclonal antibody and a standard immunohistochemical technique. Expression was scored on the basis of microscopical assessment of percentage of tumour cells staining. One patient was lost to follow-up and excluded from the study. A significant association (P < 0.0001) was observed between metallothionein expression and tumour type, with low levels being observed in tumours of good prognostic type. There was also a significant association with local recurrence (P < 0.02) and a significant difference (P < 0.02) in both survival and disease-free interval between tumours showing low and high levels of expression, the latter indicating a poor prognosis. No relationship was observed with patient age, tumour size, lymph node stage, histological grade, vascular invasion, menopausal status or oestrogen receptor status. The assessment of metallothionein expression in human breast cancer appears to provide prognostic information and may have important implications for understanding its development.

Breast Neoplasms↗
PubMed1995

Pathological prognostic factors in breast cancer. IV: Should you be a typer or a grader? A comparative study of two histological prognostic features in operable breast carcinoma.

In a study of 1529 patients with primary operable breast carcinoma we have assessed the effect of applying both histological grade and tumour type to determine their comparative value as prognostic factors in human breast cancer. The prognostic group the patient was placed in, based on histological type alone, was less accurate than using grade and type together for many tumours. The importance of performing histological grading of ductal/no special type carcinoma (50% of the women in this series) is confirmed in this series. The 10-year-survival varied from 76% for women with grade 1 carcinoma to 39% for those with grade 3 tumours. Some of the 'special types' of breast carcinoma including tubular, tubulo-lobular, invasive cribriform and grade 1 mucinous carcinomas behaved as would be predicted, with a greater than 80% 10-year-survival in this series. Others, including grade 2 mucinous carcinomas, however, behaved less well with a 60% to 80% 10-year-survival. Indeed, many of the histological tumour types including tubular mixed, ductal/no special type, mixed ductal with special type and lobular carcinomas of classical, solid or mixed types showed a variation in behaviour that could not be predicted by typing alone. Histological grade and tumour type, when used together, more accurately predicted prognosis. In multivariate analysis of a larger group of 2658 cases of primary breast carcinomas (including the 1529 study cases) when histological grade, lymph node status and tumour size were entered, grade was the most important factor in predicting for survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Diagnosis of coronary disease using echocardiography with inotropic dobutamine stimulation].

PURPOSE: To evaluate dobutamine echocardiography capacity to diagnose coronary artery disease. STUDY DESIGN: Prospective clinical study. SETTING: Cardiology Department of Hospital Santa Marta. PATIENTS: 32 patients with suspected coronary artery disease, without myocardial infarction, have been studied. METHODS: An intravenous perfusion of dobutamine with gradual doses, from 5 to 40 micrograms/kg/min, and increments of 5 to 10 micrograms/kg/min, in 3 minute stages, except the last stage which lasted only 1 minute with 40 micrograms/kg, was performed. Twelve-lead ECG were registered to detect ST changes and symptoms, namely chest pain. Basal and dobutamine bidimensional echocardiograms, in the end of each stage and during recovery, were registered in video. The segmental analysis was performed considering the left ventricle divided in 16 segments. It was considered positive the occurrence or aggravation of the contractility asynergy of the left ventricle with inotropic stress. All the patients were submitted to coronary arteriography. RESULTS: Due to the bad quality of the echocardiographic images 2 patients were excluded. The stress dobutamine echocardiograms were positive in 14 P and negative in 16 P. The coronary arteriography showed coronary disease in 18 cases and absence of significant lesions in 12 cases. The values for sensitivity, specificity positive predictive value and negative predictive value obtained with dobutamine echocardiography were, 78% and 100% and 75% respectively. In Dobutamine-ECG, 7P had ST segment changes, 2 of them with chest pain values for sensitivity, specificity, positive and negative predictive value with dobutamine-ECG were, 39%, 100% and 52%, respectively. The occurrence of side-effects was observed in 8 P (27%): ventricular tachycardia (2 P-7%), complex ventricular ectopy (4 P-13%), chest pain (2 P-7%), headache (1 P-3%), nausea (1 P-3%) and palpitations (2 P-7%). There was no significant difference in the occurrence of side-effects in the two groups of patients, with and without coronary artery disease (33% vs 17%, respectively; p = ns). The reasons for early discontinuation of dobutamine infusion were: ventricular tachycardia (2 P), complex ventricular ectopy (2 P) and chest pain (1 P). Heart rate, systolic blood pressure and double-product did not differ significantly in patients with and without coronary artery disease. In dobutamine electrocardiography 7 P had ST segment changes, 2 of them with chest pain. CONCLUSION: Dobutamine echocardiography showed in this study elevated values for sensitivity and specificity, however sensitivity can be increased with better technical conditions.

Aged↗
PubMed1994

Generation of a proton motive force by the excretion of metal-phosphate in the polyphosphate-accumulating Acinetobacter johnsonii strain 210A.

The strictly aerobic, polyphosphate-accumulating Acinetobacter johnsonii strain 210A degrades its polyphosphate when oxidative phosphorylation is impaired. The endproducts of this degradation, divalent metal ions and inorganic phosphate, are excreted as a neutral metal-phosphate (MeHPO4) chelate via the electrogenic MeHPO4/H+ symport system of the organism. The coupled excretion of MeHPO4 and H+ in A. johnsonii 210A can generate a proton motive force. In membrane vesicles and deenergized cells, a membrane potential of about -70 mV and transmembrane pH gradient of about -8 mV were formed in response to an imposed outwardly directed MeHPO4 concentration gradient of 120 mV (initial value). The MeHPO4 efflux-induced proton motive force could drive energy-requiring processes, such as the accumulation of L-proline and L-lysine and the synthesis of ATP via the membrane-bound F0F1 H(+)-ATPase. In vivo 31P NMR studies of polyphosphate degradation in anaerobic cell suspensions revealed the presence of a considerable outwardly directed phosphate gradient across the cytoplasmic membrane corresponding to a MgHPO4 concentration gradient of at least 100 mV. This MgHPO4 concentration gradient was maintained for several hours. Thus, energy recycling by MeHPO4/H+ efflux will contribute significantly to the overall production of metabolic energy from the degradation of polyphosphate in A. johnsonii 210A.

Acinetobacter↗
PubMed1993

[Percutaneous coronary angioscopy].

In the last few years, major advances in catheter technology and miniaturization of fiber optics have allowed percutaneous coronary angioscopy to become a reality. Current angioscopy systems provide an outstanding image quality yielding precise evaluation of coronary atherosclerosis morphology in its various clinical manifestations. However, coronary angioscopy is a new diagnostic tool whose indications and specific role are yet to be delineated. Investigation on the potential roles of this technology are mainly centered in the field of acute coronary syndromes and interventional coronary therapies. In the near future, coronary angioscopy may play an important role in the investigation of the natural history of coronary artery disease, in the field of thrombolysis, and in the selection of specific therapy. In this article, coronary angioscopy system and technique are described and its potential clinical applications discussed.

Angina, Unstable↗
PubMed1993

[The remote noninvasive assessment of left ventricular diastolic pressure by pulsed Doppler echography--the importance of the time of mitral protodiastolic deceleration].

UNLABELLED: To find a possible correlation between the transmitral diastolic flow, obtained by pulsed Doppler echocardiography, and left ventricular end-diastolic pressure (LVedP), we studied 95 patients (p) (58 +/- 9 years), with coronary artery disease (76 p) and dilated cardiomyopathy (19 p). P with atrial fibrillation, heart rate > 100 b/m or mitral regurgitation > 2+/4+ were excluded. We analyzed E and A wave peak velocities (v), time-velocity integrals (i) and diastolic filling intervals. Restriction to filling pattern was considered in the presence of an E wave deceleration time (DecT) < or = 120 ms (Group B- 22 p); the other 73 p (group A) ranged from abnormal relaxation to normal diastolic patterns, with DecT > 120 ms. RESULTS: -LVedP ranged from 3 to 38 mmHg in group A and from 16 to 39 mmHg in group B. In group A, the Ai/Ei ratio showed a significant linear correlation with the LVedP (r = 0.83, y = 14 chi + 2); Ai/El ratio > 1.0 identified pts with LVedP > 18 mmHg with a sensitivity of 85% and a specificity of 98%. In group B, there was a correlation between LVedP and the inverse ratio of integrals (Ei/Ai) (r = 0.72), as well as Ev/Av ratio (r = 0.69). CONCLUSIONS: In myocardial active relaxation abnormalities, Ai/Ei ratio increases proportionally to LVedP. A short DecT (< or = 120 ms) identifies a subgroup of p with predominant impairment of LV compliance and high filling pressures, in which the atrial contribution decreases as LVedP rises. Thus, whatever the prevailing mechanism of diastolic dysfunction, echo-Doppler transmitral diastolic flow can provide a noninvasive assessment of LVedP.

Adolescent↗
PubMed1993

[The recurrence of an atrial myxoma in a patient with a mechanical mitral prosthesis--apropos a case].

Recurrence of cardiac myxoma after surgery is an uncommon situation, particularly if a wide excision of the tissue under the tumour has been done. The authors report a case of a 54-year-old male presenting with a left atrial myxoma near the mitral valve, which had to be replaced by a mechanical prosthetic valve during the removal of the tumour. One year later, he was admitted to hospital with persistent fever, weight loss, and congestive heart failure. After a positive hemoculture, intravenous antibiotherapy was initiated, and twice modified because of relapsing fever. Six weeks later, he was transferred to our institution, after an episode of severe acute pulmonary edema. 2D-Doppler echocardiography suggested the possibility of prosthesis dysfunction, revealing a transprothetic diastolic flow with a high peak velocity and moderately elevated pressure half-time. No intra-atrial masses were visualized. Computed tomography was also inconclusive, because of multiple artifacts produced by the prosthesis. These results led to the performance of a cardiac catheterization with contrast ventriculography, which revealed the presence of a transprothetic gradient, and mild mitral regurgitation. The patient was submitted to cardiac surgery, which revealed a recurrent pedunculated left atrial myxoma, with mechanical obstruction of the mitral prosthetic valve. No signs of endocarditis were found. Recurrent cardiac myxomas are reviewed and discussed, as well as the specific problems of the present case, namely the presence of a mechanical prosthetic mitral valve and the initial hemoculture results, with consequent diagnostic delay.

Heart Atria↗
PubMed1993

[The pulsed Doppler evaluation of patients with dilated cardiopathy].

OBJECTIVE: To evaluate, by 2D-Doppler echocardiography, the patterns of left ventricular filling in groups of patients with left ventricular systolic disfunction and different pulmonary wedge pressures. STUDY DESIGN: perspective study of different indexes of left ventricular diastolic filling measured by Doppler echocardiography and compare them with a normal group. SETTING: Patients studied in the Cardiology Department of the Santa Marta Hospital with a diagnosis of dilated cardiopathy and submitted to cardiac catheterisation. PATIENTS: Twenty-four patients, aged 39 years old, submitted to hemodynamic study (group A) and nineteen subjects, aged 34 years old (group B). Pulmonary capillary wedge pressure (PWP) was determined in group A and the patients were divided in two groups: group A1 (with PWP < 16 mmHg) and group A2 (with PWP > or = 16 mmHg). INTERVENTIONS: Every patient was submitted to cardiac catheterisation. The echocardiographic study showed global decrease of left ventricular systolic function. With pulsated Doppler left ventricular diastolic flow indexes were determined. The following parameters were studied: peak protodiastolic flow velocity (Vel E), peak telediastolic flow velocity (Vel A), E/A ratio, protodiastolic acceleration time (O-E) and diastolic flow time (O-C). MEASUREMENTS AND RESULTS: There were no statistical differences between group A as a whole and group B. However in group A1, with a lower PWP there was a decrease of E flow velocity in relation to the control group (54.6 cm/sec +/- 14 vs 66.4 cm/seg +/- 12.8 p < 0.05) or to the group A2 (75.3 cm/sec +/- 29.9 p < 0.05). In the group A1 there was an increase of the flow velocity A in relation to group B (56.1 cm/sec +/- 15.9 vs 36.4 cm/sec +/- 7.3 p < 0.05) and to the group A2 (56.1 cm/sec +/- 15.5 vs 28.2 +/- 9.1 p < 0.05). The relation E/A in group A1 was deceased in relation to group B (1.0 +/- 0.4 m vs 1.8 +/- 0.6 p < 0.05) and in group A2 its increased in relation to B (2.6 +/- 0.9 vs 1.8 +/- 0.6 p < 0.05). The E-D time was increased in group A1 in relation to group B (162.1 +/- 8.7 cm/sec vs 140.5 +/- 42.0 cm/sec p < 0.05) and slightly reduced in group A2 (134.5 +/- 78 msec vs 140.5 +/- 42.0 msec NS). All the patients with mitral regurgitation belonged to group A2. There was only statistical difference in the velocity between the patients in group A with and without mitral regurgitation (29.6 +/- 17.4 cm/sec vs 26.4 +/- 8.5 cm/sec p < 0.05). CONCLUSIONS: In spite of some limitations, Doppler echocardiography is useful in the evaluation of left ventricular filling of patients with dilated cardiomyopathy. It shows different patterns that vary according to the hemodynamic states of the patient.

Adult↗
PubMed1993

[Contribution of Holter monitoring in the diagnosis of a case of Prinzmetal's angina].

Prinzmetal angina is a peculiar kind of angina pectoris, in which Holter monitoring has been particularly useful for diagnosis. In this paper it is reported a 56 years old male patient with coronary artery spasm induced during coronary arteriography in which the Holter electrocardiography was of most importance for decision making.

Angina Pectoris, Variant↗