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Biomedical subjects

J B Nogueira

Publications and source records attributed to J B Nogueira.

At least 19 recordsLinked to original sources
PubMed1999

[Hypertensive cardiopathy. From arterial hypertension to congestive heart failure].

Arterial hypertension (HBP) is a very important cardiovascular risk factor. According to the data from the Framingham Study, 90% of the patients with chronic heart failure (CHF) have a clinical history of HBP, and the risk of developing CHF is 2 to 3 times greater in hypertensive persons. Studies of general population by multivariate analysis have shown that HBP is responsible for 39% of CHF cases in males and 59% in females. On the other hand, there is a significant relation between HBP and coronary artery disease (CAD), another very important cause of CHF. HBP very frequently originates left ventricular hypertrophy (LVH) and this is one of the most important links between HBP, myocardium ischaemia, CAD, and sudden death from arrhythmias, to which it can lead. Recent studies on left ventricle systolic function in hypertensive patients indicate that about 1/6 of HBP patients with LVH present systolic dysfunction. Even more frequently, diastolic function is prematurely deteriorated in HBP. In spite of the existence of a significant relation between the grade of LVH and the severity of this disfunction, it may be present even before LVH is detectable. The transition from LVH would be related to quantitative and qualitative changes in the three compartments of the myocardium: hypertrophy of cardiomyocytes with reinduction of fetal genetic program, reactive and cicatricial fibrosis of the interstice, and functional and structural changes of coronary arteries. These modifications will progressively increase, leading to LV dilation which seems to signal transition to heart failure. In recent papers the transition from LVH to CHF has been related to a marked increase in microtubular intracytoplasmic structure, the reduction of Ca++ ATPase concentration of the sarcoplasmic reticulum, and the increased myocardial expression of growth factor TGF beta 1, which influences interstitial fibrosis. In the same way, stimulation of apoptosis by myocardial expression of tumor necrosis factor alpha and the subquent increase in inducible NO-synthase and oxidative stress has been related to the progression for CHF. Prevention of CHF will not only consist in the treatment of HBP but, very probably, also in the prevention of regression of LVH, and normalization of myocardial components, as well as the correction of all the factors involved in CHF establishment. In accordance with form of treatment, we must give special emphasis to drugs interfering with the renin-angiotensin system and, possibly in the near future, to gene therapy.

Arteriosclerosis↗
PubMed1998

Comparison of the contractile performance of the hypertrophied myocardium from spontaneous hypertensive rats and normotensive infarcted rats.

The sarcoplasmic reticulum (SR) exerts a key role on the excitation-contraction coupling process in the myocardium. Since the relation between the volume of cellular organelles, such as SR, and the sarcolemmal area of myocytes is not uniform in myocardial hypertrophy of different etiologies, we compared the contractile performances of hypertrophied left ventricular papillary muscles from rats with pressure overload and with volume overload. Hemodynamically compensated spontaneous hypertensive rats (SHR, 3 months old, systolic blood pressure = 189 +/- 4 mmHg, n = 8) and Wistar rats with healed (30 days) myocardial infarction (MI, n = 7) produced by ligation of the left coronary artery were used. Results were compared with age-matched Wistar control (CON) rats (n = 13). Force (F), corrected to muscle cross-sectional area (g/mm2), and dF/dt were recorded in muscles contracting isometrically and stretched to Lmax. The inotropic response to increasing extracellular Ca2+ concentrations (1.25 to 5.0 mM) was compared in twitches (0.5 Hz) and during tetanic stimulation (5 Hz, 30 s) in the muscles treated with 1 microM ryanodine. F recorded in basal conditions (Ca = 1.25 mM, 0.5 Hz) in the CON group (1.34 +/- 0.20 g/mm2) was higher (p < 0.05) than in the MI (0.73 +/- 0.13 g/mm2) and lower (p < 0.05) than in the SHR group (2.08 +/- 0.25 g/mm2). Similar differences between groups were also observed in relation to +dF/dt. Increasing extracellular Ca produced a parallel increase of F and +dF/dt in the three groups of muscles. Ryanodine treatment reduced F and +dF/dt in all groups and completely inhibited the development of force in post-rest contractions, indicating SR inhibition. SHR muscles were more sensitive to ryanodine than CON and MI (F decrease = 64 +/- 7, 51 +/- 5, and 22 +/- 5%, respectively, p < 0.05). The tetanic tension (Ca = 1.25 mM) was similar in SHR and CON (0.82 +/- 0.19 and 0.92 +/- 0.18 g/mm2; p > 0.05) and depressed in the MI group (0.35 +/- 0.12 g/mm2). These data suggest an increased participation of SR as source of activator Ca in the hypertrophied muscle of SHR. This adaptation likely contributes to maintain the normal cardiac function in hemodynamically compensated SHR, despite increasing afterload levels. This adaptation seems not to occur after MI, which may contribute to the depressed contractile performance of the left ventricular muscle surviving to infarction.

Animals↗
PubMed1997

[A structural analysis of the entrance exams for specialist interns from 1994 to 1996].

In order to obtain specialist training in Portugal, doctors must pass a multiple-choice examination. The aim of this article is to present a structural and mathematical analysis of the examinations in the last three years. We based our work on the calculation of reliability coefficient of the examinations, and the difficulty and discrimination index of the questions and the examinations as a whole. A detailed analysis of the examinations, including that of each of the three hundred questions, will be published by the Department of Health Manpower in January, 1997.

Education, Medical↗
PubMed1995

[Acute cerebrovascular accident and heart disease. Prospective study of 248 patients].

OBJECTIVE: To evaluate the heart disease associated to different type and sub-types of cerebrovascular disease with particular reference to potential cardiac sources of embolus (CPE). DESIGN: Prospective study in 248 consecutive patients with acute stroke, admitted to a Clinical Medicine Unit in three independent time periods. SETTING: Internal Medicine Clinic of University Hospital in Lisbon. METHODS: Neurologic and cardiologic examination were performed and all patients were also submitted to different complementary tests, including a Computer Tomography Scan of the brain (TAC) and a Echocardiogram (ECO). We identified two types and two sub-types: intracerebral haemorrhage (HI) or ischemic stroke (AI) and among AI, cortical (C) or subcortical (SC) ischemic stroke. For each type and sub-type we evaluated past history, heart disease, hypertension (HTA), electrocardiogram, echocardiogram (ECO) and CPE. PATIENTS: Two hundred and forty eight patients (52% were men) with mean age 68.0 +/- 10.2 years and ages between 40 and 92 years. Thirty seven (15%) died. MAIN RESULTS: Eighty four percent were AI and among them 45% were C. Previous strokes were more prevalent in AI 29% (p < 0.01). There was heart disease in 81% and hypertensive cardiopathy was more frequent in HI 63% (p < 0.002). HTA and atrial fibrillation (FA) were more frequent in HI 83% (p < 0.05) and in AI 25% (p < 0.004) respectively. ECO showed a dilatation of left atrium more frequent in AI 28% (p < 0.05) and left ventricular concentric hypertrophy index (IHCE) in HI 50% (p < 0.05). CPE, including FA, was identified in 34% of patients, was more prevalent in AI 38% (p < 0.001) and among it FA was significantly more frequent in C 32% (p < 0.02). CONCLUSIONS: Heart disease is very frequent in stroke. The diagnosis of this condition is very important for stroke prophylaxis and prognosis. HTA and hypertensive cardiopathy have a great prevalence and were more related to HI. CPE and FA were very frequent and their diagnosis are important for prevention of AI and specially for embolic stroke. ECO is useful to identify CPE in elderly patient in particular to characterize heart disease.

Acute Disease↗
PubMed1993

[Assessment of arterial occlusive disease with Duplex sonography. Prospective study].

Occlusive disease involving the renal arteries represent a major cause of curable hypertension and improvement of renal dysfunction. Angiography is still the major diagnostic procedure. Isotopic methods with Captopril and split-function studies have shown high incidence of false-positive and false-negative results. Colour flow Duplex-Scan renders possible the visualization of the aorta and renal arteries, is noninvasive and combines morphologic and hemodynamic evaluation. To assess its efficacy in the diagnosis of renal artery occlusive disease, a prospective blind study was undertaken in 24 patients, 48 renal arteries, 15 women and 9 men, with mean age of 44 years. Scans of the aorta and renal arteries at the origin, along its extension and at the renal hilum were obtained using and ATL Ultrmark 9 with 3.0 MHZ probe Velocity measurements were obtained at the aorta and along the renal arteries. Criteria for a positive examination were: focal acceleration with a reduction of the flow velocity at the hilum. Absence of flow in a properly visualized renal artery was considered as occlusion. All patients had digital subtraction arteriography. In 1 patient the non-invasive examination was inadequate. In the remain 23 patients the exam was considered adequate. False-positives were 4.8%; false-negatives 8.7%. Sensitivity, specificity and accuracy were respectively 91.7%, and 95.7% and 93.5%. These results suggest that non-invasive assessment of renal artery occlusive disease is feasible and accurate when compared to angiography, thus providing a useful tool for screening hypertensive patients.

Adolescent↗
PubMed1992

[Precocity of diastolic dysfunction in hypertensive cardiopathy].

Left ventricular hypertrophy (LVH) is a well defined cardiovascular risk factor and is frequently detected by echocardiography in hypertensive patients. Systolic cardiac function at rest is usually preserved in hypertension, however, diastolic function may be frequently altered. Evidence for these changes has been demonstrated by Echo-Doppler even without concomitant existence of LVH. Quantitative and qualitative changes in contractile proteins and interstitial tissue as well as reduction of coronary reserve may be related to the mentioned dysfunction. Recent studies have confirmed the precocity of diastolic dysfunction both in laboratory animals as well as man. Further significant differences have been shown between normotensives with and without a family history of systemic hypertension. The relative importance of diastolic disfunction is also related to its possible role in the genesis of cardiac failure and its probable role in the modulation of cardiopulmonary reflexes in addition to the hemodynamics of arterial hypertension. It is not yet known if the presence of diastolic dysfunction is a mechanism or a risk marker like LVH.

Cardiomegaly↗
PubMed1992

[Hypertensive cardiopathy. Functional evaluation during isometric effort after regression of left ventricular hypertrophy].

OBJECTIVE: Echocardiographic evaluation of the response to isometric exercise of hypertensive patients with and without left ventricular hypertrophy. PARTICIPANTS: 28 patients with severe arterial hypertension on long-term follow-up with or without regression of left ventricular hypertrophy on medical therapy; a control group of 10 healthy volunteers. METHODS: Two groups were considered: Group A persistent left ventricular hypertrophy and group B normalization of the left ventricular wall thickness and mass index. The arterial blood pressure and heart rate were evaluated and an echocardiographic record was obtained both at rest and after isometric exercise (maximal effort for 1 to 1.5 minutes). The following echocardiographic data were obtained: left ventricular diameters and thickness of septum and posterior wall during systole and diastole. Volumes, shortening and ejection fractions, cardiac output and index, mass index, end-systolic stress, contractility index and periferal resistance were calculated as usual. RESULTS: During isometric exercise there was a rise in systolic, diastolic and mean arterial pressures and heart rate. Systolic function was normal in all groups at rest. The shortening fraction was not altered in normotensive individuals with isometric exercise. Hypertensive patients showed a significant reduction within normal limits, however. End-systolic stress increased significantly in all groups although the rise was greater in hypertensive patients. The cardiac index rose significantly only in normotensives and hypertensive patients without left ventricular hypertrophy (group B). On the contrary the periferal resistance rose significantly only in hypertensive patients with left ventricular hypertrophy (group A). The contractility index (end-systolic stress/end-systolic volume index) increased significantly only in normotensive and hypertensive patients without left ventricular hypertrophy. CONCLUSIONS: There are functional alterations in hypertensive heart disease which although not evident at rest, can be revealed by isometric exercise. The regression of left ventricular hypertrophy back to normal, sets a trend for normalization of function and cardiac inotropic reserve, suggesting the importance of a complete regression of ventricular hypertrophy.

Adult↗
PubMed1991

[Arterial hypertension and the right heart. A hemodynamic and echocardiographic study].

OBJECTIVE: To evaluate the effects of arterial hypertension on the pulmonary circulation and the right heart. SETTING: Coronary Care Unit (UTIC Arsénio Cordeiro) Hemodynamics Laboratory and Medicine I Echocardiography Laboratory-Santa Maria Hospital. PARTICIPANTS: 38 hypertensive patients separated in two groups: 24 with thickened septum and left ventricular posterior wall (10 with hemodynamic evaluation)--Group A--and 14 without thickening--Group B; a control group of 12 healthy volunteers--Group C. RESULTS: The hypertensive patients with hemodynamic evaluation had normal pulmonary capillary wedge pressure the average pulmonary resistance (135.29 +/- 63.47 dyn.cm.5), pulmonary systolic (31.30 +/- 10.01 mmHg) and mean pressures (18.23 +/- 8.21 mmHg) were raised, but the diastolic pulmonary pressure was normal. The right ventricle systolic pressure was raised (32.10 +/- 9.12 mmHg) and there was no modification of the right atrial or ventricular telediastolic pressures. On echocardiography there was a diastolic thickening of the right ventricular free wall in both group A (7.08 +/- 1.41 mm) and B (4.07 +/- 1.00 mm) as compared to group C (3.08 +/- 0.51 mm); there were similar findings regarding systolic thickness with statistical significance in group A (p less than 0.001). The right ventricular ejection fraction was normal in both groups. There was a positive correlation between the diastolic thickness of left ventricular posterior wall and right ventricular free wall in hypertensive patients and normotensive volunteers (r = 0.7754; p less than 0.001). CONCLUSIONS: The findings suggest an anatomic an functional relationship between both ventricles regarding the cardiac repercussions of arterial hypertension.

Adult↗
PubMed1990

[Hypertensive hypertrophy of the left ventricle: its regression in hypertensive patients with different profiles of plasma renin activity, treated with enalapril].

STUDY OBJECTIVE: To determine the action of enalapril maleate in cardiac mass and ventricular performance; to investigate virtual differences of anti-hypertensive action, and regression of left ventricular hypertrophy, between subgroups of patients with different profiles of plasma renin activity (PRA). DESIGN: Randomized, single-blind, placebo-controlled study, along 14 weeks, the last 12 under active treatment with enalapril maleate. SETTING: Outpatient clinics of an university department of Internal Medicine and Cardiology. PATIENTS: Sequential series of twenty patients with mild to moderate essential hypertension. Two patients were lost to follow-up. Eighteen patients completed the study. Seventeen out of them were studied for plasma renin activities, and echocardiographic measurements were performed in ten, during the 2 weeks placebo period, and by the end of active treatment. No patients were excluded because of side-effects. INTERVENTION: After a 2-weeks washout period, enalapril maleate has been given in a single daily dose of 20 mg, at bedtime. In 14 patients the dosage was elevated to 40 mg once daily and, in 5 out of these, 12.5 mg hydrochlorothiazide once a day has been added. MEASUREMENTS AND MAIN RESULTS: The mean of systolic/diastolic sitting blood pressures was reduced from 171.6/112 to 151.6/98.1 mmHg (p less than 0.001). The mean of systolic/diastolic standing blood pressures lowered from 167.8/113.7 to 148.6/99.6 mmHg (p less than 0.001). No significant differences were found between blood pressure reductions in 5 patients with elevated PRA, 5 patients with slightly elevated PRA, and 7 patients with normal or low PRA. The analysis of echocardiographic measurements revealed regression of left ventricular hypertrophy (LVH) and, in one patient who had no criteria of LVH, actually occurred reduction of the thickness of ventricular walls. No unfavourable influence over ventricular function indices, neither systolic nor diastolic, was found. End-systolic stress and inotropic activity remained unchanged. The tolerability of the study drug was very good. CONCLUSIONS: Enalapril maleate appears, in this study, an effective anti-hypertensive compound. Its therapeutic action seems independent of the plasma renin activity profile. The drug induced regression of left ventricular hypertrophy after a period of 12 weeks of treatment, and did not promote any unfavourable influence over ventricular functions indices. Inotropic activity and end-systolic stress were not modified. The tolerability was very good.

Cardiomegaly↗