[Focal cerebral ischaemia induced by middle cerebral artery occlusion and the neuroprotective effect of ketoprofen in rats]

Cerebral ischaemia is eventualy observed during neurosurgical procedures and in several clinical entities that may cause severe neurological deficits and even death. Because it is a severe and complex problem, several studies have been done aiming to elucidate the mechanisms of the ischemic phenomenon and aiming to abolish or to diminish its effects, using drugs that protect the neurons from ischaemia-induced damage. Several neurotransmitters play a role in cerebral ischaemia with emphasis to glutamate by its high concentration in the central nervous system. The purpose of this study was to evaluate the effect of focal cerebral ischaemia in the rat through the dosage of the glutamate and morphological findings, and to evaluate a possible protective effect of the ketoprofen to ischemic neurons. Thirty-six rats Wistar were divided into four groups. The first was a control group, the second a sham group and the animals of the third and fourth groups were submitted to induced cerebral ischaemia through selective obstruction of the midlle cerebral artery during 15, 30 and 45 minutes. Animals of the fourth group were previously treated with ketoprofen 15 minutes before the ischaemia. The ischaemia was evaluated through the histopathological examination and through dosage of the extracellular glutamate in vitro. The histopathological examination showed that there was no difference between the animals of the control and of the sham groups. In the animals submitted to ischemia histopathological alterations appeared at 30 minutes and become more intense at 45 minutes of ischaemia. The main findings were interstitial edema, chromatinic disorganization, vacuolization and nuclear desintegration. The animals treated with ketoprofen showed similar alterations, but they were less intense. Decrease in the dosage of glutamate in the parietal cortex of the animals submitted to ischaemia started at 30 minutes and became more intense at 45 minutes of ischaemia and was similar for animals previously treated or not with ketoprofen, indicating that this drug seems not to interfere with the metabolism of the glutamate at the synapses. The morphological findings in the parietal cortex of the animals submitted to ischaemia, previously treated or not with ketoprofen, suggest that this drug has a neuroprotective effect.

[Plasmodium falciparum malaria. Quadrennial analysis, during 12 years, of the efficacy of quinine treatment]

The efficacy of quinine for the treatment of falciparum malaria was studied by quadriennal analysis of the medical records of 454 patients admitted to the HDT-GO from 1983 to 1994 and treated with identical doses of quinine alone for 7 days. In the quadriennium from 1983 to 1986, 98.4% of the patients became negative by the 5th day of treatment and 8% presented recurrence (R1); from 1987 to 1990, only 72.9% became negative by the 5th day of treatment, 1.4% remained positive until the 7th day (R2) and 9.7% presented recurrence (R1); from 1991 to 1994, 70.1% became negative by the 5th day of treatment, 3.5% remained positive until the 7th day (R2) and 20% presented recurrence (R1). The increase in parasite clearance time with failure up to the 7th day of treatment (R2) and the increase in recurrence (R1) show that P. falciparum is developing resistance to quinine in the region under study.

Intoxication by star fruit (Averrhoa carambola) in six dialysis patients? (Preliminary report)

We observed six cases of patients in a dialysis programme who were apparently intoxicated by ingestion of star fruit. After ingestion of 2-3 fruits or 150-200 ml of the fruit juice, the six patients, who had previously been stable in a regular dialysis programme, developed a variety of symptoms ranging from insomnia and hiccups to agitation, mental confusion and (in one case) death. In preliminary investigations to characterize the hypothetical neurotoxin in the fruit, an extract, when injected intraperitoneally or intracerebroventricularly in rats, provoked persistent convulsions of the tonic-clonic type. It appears that star fruit (Averrhoa carambola) contains an excitatory neurotoxin. Patients with renal failure on conservative or dialysis treatment should be dissuaded from ingestion of the fruit.

Physical activity, opportunity for reinfection, and sibling history of heart disease as risk factors for Chagas' cardiopathy

A case-control study was conducted to examine whether physical activity, sibling history of heart disease (HHD), and length of residence in an area endemic for Chagas' disease were associated with the risk of developing Chagas' cardiopathy. Two hundred forty-seven cases of Chagas' heart disease and 345 seropositive subjects with normal ECG (controls) were selected in a population survey in Goiânia, Brazil. Prevalence ratios for exposure variables were estimated for cases in relation to controls and for subgroups of seropositives with selected ECG abnormalities in relation to controls. Increasing age and male sex were consistently and significantly related to an increased risk of ECG abnormalities. HHD was significantly associated with ECG alterations in 3 of the 5 comparison subgroups (any ECG alteration, right bundle branch block, and left anterior hemiblock). No association was found between length of residence in an area endemic, physical activity, and ECG abnormalities. A sample of 529 seronegative subjects were also examined and the interaction between exposure variables and seropositivity was tested to assess whether the associations found were specific for seropositives. Males were at greater risk of any ECG alteration and left anterior hemiblock in relation to females if they were seropositive. An increasing risk of ventricular premature beats with age was clearer for seropositive than for seronegative subjects. Subjects with HHD were at an increased risk of ECG abnormalities and this was greater in those with a positive serological test (P less than 0.05). The findings suggest a possible geographical clustering or a familial aggregation of cases of Chagas' heart disease.

Exercise electrocardiogram tests in manual workers with and without antibodies to Trypanosoma cruzi: a population-based study

Blood pressure, heart rate and electrocardiographic responses to exercise were compared in a group of 125 subjects with antibodies to Trypanosoma cruzi and in 153 seronegative subjects, randomly selected from persons with no evidence of heart disease in a resting electrocardiogram during a cross-sectional survey among apparently healthy manual workers. The mean heart rates and diastolic and systolic blood pressures of those in each group did not differ statistically at different phases of the exercise test and there was no evidence of a difference in physical fitness between those in the 2 groups. An abnormal test was recorded in 26.2% of seropositive, and in 16.1% of seronegative, subjects (odds ratio adjusted for age, sex and body mass index [OR] = 2.0, 95% confidence interval [95% CI] = 1.1-3.8). No significant difference was observed between the 2 groups in the occurrence of hypertensive response to exercise (6.4% among seropositives and 5.9% among seronegatives), ST depression greater than 1 mm (0.8% and 2.0%), supraventricular premature beats (4.8% and 2.6%) or conduction defects (0.8% and 1.3%). Complex ventricular premature beats were recorded more often in seropositive subjects (12.8% and 3.9%; OR = 3.7, 95% CI = 1.4-9.8, P less than 0.01). The risk of an abnormal test increased with age in both groups. A history of cardiovascular symptoms, gender and body mass was not associated with the risk of an abnormal response in the test. The findings suggest that exercise testing might be a routine procedure when subjects with antibodies to T. cruzi are being assessed for participation in potentially high risk activities, such as heavy manual work.

Trypanosoma cruzi infection and electrocardiographic findings among active manual workers. A population-based study in central Brazil

In a cross sectional survey of the prevalence of Trypanosoma cruzi infection among urban unskilled workers in Goiânia, Brazil, blood samples from 6222 manual workers from seven institutions were examined for anti-Trypanosoma cruzi antibodies by immunofluorescence, ELISA and haemagglutination tests. ECGs were performed and a clinical history was taken from 624 seropositive and a random sample of 529 seronegative subjects. Abnormal ECGs were found in 15.1% of individuals without Trypanosoma cruzi antibodies and in 44.4% of those with antibodies (p less than 0.001). In general, cardiovascular symptoms reported were not associated with seropositivity nor with ECG alterations but dizziness and dyspnoea were more often reported among those with an abnormal tracing (p less than 0.01). The prevalence of ECG abnormalities increased with age in both groups but was higher among those seropositive in all age groups. An odds ratio of 2.0 (95% Cl 1.2-3.1) and 2.9 (95% Cl 1.5-6.3) of ECG abnormalities, for each decade of life, was estimated for seropositive and seronegative subjects, respectively. Relative risks (based on the odds ratios) for various specific ECG abnormalities, comparing seropositive to seronegative individuals, were calculated after adjustment for age, sex and institution. The odds ratio for complete right bundle branch block was 49.9 (95% CL 12.2-203.4); for left anterior hemiblock was 4.1 (2.8-6.0); for large Q/QS waves was 4.2 (2.4-7.3) and for first degree A-V block was 8.5 (2.6-28.1).

Supersensitivity of the isolated guinea-pig vas deferens induced by a toxic fraction of scorpion venom (Tityus serrulatus)

Tityustoxin (TsTx), a toxic fraction of Tityus serrulatus venom, was studied on the isolated guinea-pig vas deferens. It increased significantly the maximal response of the preparation to both norepinephrine and acetylcholine and decreased the effective median dose of norepinephrine. The effect of TsTx on norepinephrine median dose was unchanged when atropinized or pharmacologically "denervated" preparations were used but was abolished when both procedures were associated. Atropinization of pharmacologically denervated muscles almost never modify the TsTx-induced increase in the maximal response to norepinephrine. On denervated or phentolamine-treated muscles TsTx-induced increase in the maximal response to acetylcholine was abolished. It was concluded that toxin predominantly induces adrenergic postsynaptic supersensitivity. Of minor significance, it also induces presynaptic cholinergic and adrenergic supersensitivity. Comparison of these results with those of crude venom indicates that TsTx effects may result from the sum of the effects of subcomponents not demonstrated by the chemical procedures here utilized.