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Biomedical subjects

L Martins

Publications and source records attributed to L Martins.

At least 37 records · Page 2Linked to original sources
PubMed2000

Evaluation of brain natriuretic peptide in the diagnosis of heart failure.

A diagnosis of heart failure (HF) can be difficult, especially in patients with mild symptomatology. The purpose of this study was to evaluate the significance of brain natriuretic peptide (BNP) in the diagnosis of HF with systolic or isolated diastolic ventricular dysfunction. One hundred patients and 9 controls were included in the study. Eighty-five patients were diagnosed with HF, based on clinical and echocardiographic findings. BNP levels were accurate for the diagnosis of HF, with an area under the receiver operating characteristic (ROC) curve (AUC) of 0.92. In addition, BNP levels showed an excellent accuracy for the diagnosis of isolated diastolic HF (AUC = 0.89). These data suggest that the measurement of BNP levels may be helpful in the diagnosis of HF and in selecting patients for further evaluation. Furthermore, BNP measurement can play an important role in the diagnosis of isolated diastolic HF.

Aged↗
PubMed1999

Telomere dynamics, end-to-end fusions and telomerase activation during the human fibroblast immortalization process.

Loss of telomeric repeats during cell proliferation could play a role in senescence. It has been generally assumed that activation of telomerase prevents further telomere shortening and is essential for cell immortalization. In this study, we performed a detailed cytogenetic and molecular characterization of four SV40 transformed human fibroblastic cell lines by regularly monitoring the size distribution of terminal restriction fragments, telomerase activity and the associated chromosomal instability throughout immortalization. The mean TRF lengths progressively decreased in pre-crisis cells during the lifespan of the cultures. At crisis, telomeres reached a critical size, different among the cell lines, contributing to the peak of dicentric chromosomes, which resulted mostly from telomeric associations. We observed a direct correlation between short telomere length at crisis and chromosomal instability. In two immortal cell lines, although telomerase was detected, mean telomere length still continued to decrease whereas the number of dicentric chromosomes associated was stabilized. Thus telomerase could protect specifically telomeres which have reached a critical size against end-to-end dicentrics, while long telomeres continue to decrease, although at a slower rate as before crisis. This suggests a balance between elongation by telomerase and telomere shortening, towards a stabilized 'optimal' length.

Cell Line, Transformed↗
PubMed1999

Brain natriuretic peptide as a marker of cardiac involvement in hypertension.

Hypertensive patients with heart abnormalities have increased risk of cardiovascular events. Brain natriuretic peptide is a natriuretic peptide mainly of ventricular origin produced in response to pressure and stretch. We hypothesise that brain natriuretic peptide could be a useful marker of cardiac remodelling in hypertensive patients. We studied 36 consecutive community mild-to-moderate hypertensive patients and 11 well-matched normotensive controls with respect to clinical characteristics, brain natriuretic peptide, creatinine and echocardiography parameters (M-mode, 2-D arid transmitral pulsed Doppler). Brain natriuretic peptide levels were significantly higher in hypertensive patients than in controls [36.54 (IQR: 38.61) vs. 10.30 (IQR: 13.20) pg ml(-1), p<0.0001] and it was correlated with left ventricular mass index. Hypertensive patients with impairment of diastolic filling had significantly higher brain natriuretic peptide concentrations than patients with no abnormalities on echocardiography [61.16 (45.38) vs. 31.27 (18.10) pg ml(-1), p=0.001]. Multivariate analysis showed that only diastolic dysfunction and left ventricular mass index were significantly and independently related with brain natriuretic peptide concentrations in this population. In conclusion, impairment of diastolic function and left ventricular mass index are related to brain natriuretic peptide levels, thus giving the insight that this peptide can be a marker of ventricular remodelling in hypertensive patients.

Aged↗
PubMed1999

The influence of interstitial telomeric sequences on chromosome instability in human cells.

Although most telomere repeat sequences are found at the ends of chromosomes, some telomeric repeat sequences are also found at intrachromosomal locations in mammalian cells. Several studies have found that these interstitial telomeric repeat sequences can promote chromosome instability in rodent cells, either spontaneously or following ionizing radiation. In the present study we describe the extensive cytogenetic analysis of three different human cell lines with plasmids containing telomeric repeat sequences integrated at interstitial sites. In two of these cell lines, Q18 and P8SX, instability has been detected in the chromosome containing the integrated plasmid, involving breakage/fusion/bridge cycles or amplification of the plasmid DNA, respectively. However, the data suggest that the instability observed is characteristic of the general instability in these cell lines and that the telomeric repeat sequences themselves are not responsible. Consistent with this interpretation, the chromosome containing an integrated plasmid with 500 bp of telomeric repeat sequences is highly stable in the third cell line, SNG28, which has a relatively stable genome. The stability of the chromosome containing the integrated plasmid sequences in SNG28 makes this an excellent cell line to study the effect of ionizing radiation on the stability of interstitial telomeric sequences in human cells.

Carcinoma, Squamous Cell↗
PubMed1999

Pericardial involvement in human immunodeficiency virus infection.

STUDY OBJECTIVES: Previous studies have showed that the pericardium is frequently involved in HIV infection. However, the characteristics and etiology of the pericardial abnormalities that have been found remained poorly defined. We analyzed the features of pericardial involvement in these patients and investigated the clinical variables associated with moderate and severe effusions. DESIGN: Prospective, clinical, and echocardiographic study. SETTING: The service of infectious diseases of a university hospital. PATIENTS: 181 consecutive patients at all stages of HIV infection. RESULTS: Only one patient (0.55%) had acute pericarditis. Seventy-five patients (41%) had an asymptomatic pericardial effusion; in 23 patients (13% of all patients), the effusion was either moderate or severe. Ten cases (5.5% of all patients) of moderate or severe effusions resulted in right atrium diastolic compression, and three of these cases (1.6% of all patients) required pericardiocentesis for the management of tamponade. Six patients (3%) presented with echogenic pericardial masses of undetermined etiology. A moderate or severe effusion was present in a greater number of patients with symptomatic HIV infection than was present in asymptomatic HIV-infected patients, respectively: 17 vs 2% (p = 0.015). The following are variables independently associated with moderate or severe pericardial effusions: heart failure (odds ratio, 20.3; p = 0.0001); Kaposi's sarcoma (odds ratio, 8.6; p = 0.01), tuberculosis (TB; odds ratio, 47.2; p = 0.0006); and other pulmonary infections (odds ratio,15.0; p = 0.02). CONCLUSIONS: Most of these moderate or severe effusions are clinically unsuspected, but they can lead to life-threatening tamponade. This fact seems to justify echocardiographic surveillance in HIV-infected patients, especially in those with heart failure, Kaposi's sarcoma, TB, or other pulmonary infections.

Adult↗
PubMed1998

Left ventricular dysfunction in human immunodeficiency virus (HIV)-infected patients.

We evaluated left ventricular function by echocardiography in a prospective study that included 98 consecutive human immunodeficiency virus (HIV)-infected patients and 40 HIV-seronegative normal controls. When compared with controls, HIV patients showed increased isovolumic relaxation time (101+/-18 ms versus 71+/-10 ms; p<0.0001) and left ventricular diastolic diameters (51+/-6 mm versus 47+/-3 mm; p<0.0005), and decreased fractional shortening (31+/-6% versus 37+/-2%; p<0.0001). Diastolic dysfunction was the most frequent finding (63% of the patients). We found depressed ejection fraction in 31 (32%) patients. Only 8 (8%) patients had symptomatic congestive heart failure. Left ventricular dysfunction was not attributable to intravenous drug abuse or to therapy. It was less severe in earlier stages of the infection (fractional shortening: acquired immunodeficiency syndrome=30%+/-6%, asymptomatic HIV-seropositives 34%+/-5%; p<0.005) and in HIV-2-infected patients. Patients with opportunistic infections (all aetiologies mixed) had more frequent congestive heart failure than those without infections (16% of the patients with versus 4% of the patients without infections; p<0.05). The fact that even asymptomatic HIV-seropositives had signs of left ventricular dysfunction (fractional shortening: asymptomatic HIV-seropositives=34%+/-5%; controls=37%+/-2%; p<0.05) favours the hypothesis of the HIV being one of the causes of these abnormalities.

AIDS-Related Opportunistic Infections↗
PubMed1998

Predictors of myocardial dysfunction in human immunodeficiency virus-infected patients.

BACKGROUND: Some of the most frequent manifestations of heart involvement in human immunodeficiency virus (HIV) infection include right and left ventricular dysfunction. The pathogenesis remains obscure. METHODS AND RESULTS: This prospective clinical and echocardiographic study involved 181 patients at all stages of HIV infection. We tested a set of clinical variables using a backward logistic regression model to assess their ability to independently predict the presence of ventricular dysfunction. The presence of pulmonary infections (all etiologies mixed) was the only variable independently associated with isolated right ventricular dysfunction (odds ratio = 4.08; P = .02). Signs suggestive of pulmonary arterial hypertension were present in 71% of the patients with right ventricular dilation. History of previous opportunistic infections (all etiologies mixed) (odds ratio = 10.9; P = .0026) and time since the diagnosis of acquired immunodeficiency syndrome more than 12 months (odds ratio = 6.6; P = .03) were the only two independent predictors of left ventricular dysfunction. CONCLUSIONS: Isolated right ventricular dysfunction may be secondary to pulmonary hypertension caused by repetitive pulmonary infections and not to primary myocardial disease. The aggressive treatment of opportunistic infections may become an important element of heart failure prophylaxis in HIV infection because they may be associated with left ventricular dysfunction.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Spinal cord injuries--epidemiology in Portugal's central region.

This study concerns spinal cord injuries (SCI) in a region of Portugal with a population of 1,721,650 inhabitants. Legislation has made it possible to identify deaths occurring during collection and transport. Between 1989 and 1992, 398 new cases of spinal cord injuries were identified, of which 77% were male and 23% female. The average age was 50, with a range of between 1 and 92. As far as the type of injury is concerned, there were 154 isolated SCI (38.7%); in 120 cases (30.1%) there were multiple associated injuries; in 66 cases (16.6%) there was an associated traumatic brain injury; in 34 cases (8.5%) there was an associated trauma of the thorax. In the hospitals concerned no Injury Severity Score (ISS) was carried out during hospitalization. Sixty-four (16%) were dead upon arrival at hospital, and 159 (40%) died before release. The average length of hospitalization was 26.6 days, with the maximum being 539 days. The annual incidence rate is 57.8 new cases per million inhabitants, including those who died before being admitted to hospital. The annual survival rate is 25.4 new cases per million inhabitants. The death rate is very high during the first week, peaking during the first 24 h.

Female↗
PubMed1997

[Acute pancreatitis and pregnancy].

Acute pancreatitis during pregnancy is a rare and serious condition with a difficult diagnosis. The authors report a case of acute pancreatitis in a 37 year old woman in the 32nd week of pregnancy. Gallstones were the etiology found. One week after support care as medical management, a recurrent episode of pancreatitis occurred. The choice treatment was endoscopic retrograde cholangiopancreatography (ERCP) with endoscopic sphincterotomy. This procedure improved symptoms. Delivery, puerperium and breastfeeding occurred without any problem. Surgery (cholecystectomy) was performed 15 days after delivery, during a new acute episode. The Authors discuss the etiopathogenic, diagnostic and therapeutic management, feto-maternal morbidity and mortality for acute pancreatitis in pregnancy.

Acute Disease↗
PubMed1997

[Transient hyperthyroidism and hyperemesis gravidarum].

Subclinical hyperthyroidism in hyperemesis gravidarum is a well-documented matter in the literature. A case report is present with the main etiologies, clinical manifestations, differential diagnoses, therapeutical guidelines and maternal-infant prognosis are discussed.

Adult↗
PubMed1996

Lisinopril and diltiazem reduce left ventricular mass without changing blood pressure in normotensive subjects with exaggerated blood pressure response to exercise.

OBJECTIVE: To determine whether high left ventricular mass may be reduced by antihypertensive drugs in normotensives with exaggerated blood pressure response to exercise as it occurs in hypertensive patients. DESIGN AND METHODS: Randomized, single blind, controlled parallel study evaluating the influence of placebo; lisinopril 20 mg/day, diltiazem 180 mg/d for 5-6 months on left ventricular mass (LVM), evaluated by echo and on "casual" and 24-h ambulatory blood pressure (24-h BP) in normotensive subjects with exaggerated blood pressure response to exercise (Group I) and in weight--and age--matched mild-moderated hypertensive patients (Group II), all with high left ventricular mass. PATIENTS: Placebo, lisinopril and diltiazem, were administered for 5-6 months in respectively 8+9+9 subjects of Group I and 8+9+10 patients in Group II. RESULTS: Placebo did not change either LVM index or 24-h BP values in Group I and Group II. Diltiazem and lisinopril reduced LVM index in both Groups I and II but 24-h BP values were only reduced in Group II. Lisinopril appeared to be more potent than diltiazem on LVM regression. Slopes of LVM index regression were not different between Groups I and II for each drug. Drug-induced changes of LVM index did not correlate with blood pressure changes. CONCLUSIONS: Drug-induced regression of LVM may be achieved in man (Group I) without any reduction of blood pressure. This may be explained by interference with growth-promoting systems other than with cardiac unloading. Also, the similar pattern of LVM regression that was observed in both Groups I and II suggests that similar underlying mechanisms may be involved in the LVH regression in these two populations.

Adult↗
PubMed1995

Cranio-orbital approach for the paraclinoidal and anterior communicating aneurysms.

Aneurysms arising at the proximal intracranial carotid artery (between cavernous sinus and posterior communicating artery) and at the anterior communicating complex may present with technical difficulties regarding appropriate access without excessive brain retraction. In a series of 15 patients the authors show the use of the cranio-orbital approach, formerly designed in the access of skull base tumors, for these subgroups of aneurysms. They discuss the advantages of a basal avenue in minimizing brain retraction, better anatomical orientation, obviation of tissue ressection and easier extra-dural bone removal. It was not identified any complication due to the described approach.

Adult↗