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Biomedical subjects

J S Oliveira

Publications and source records attributed to J S Oliveira.

At least 19 recordsLinked to original sources
PubMed1998

HTLV-I infection among relatives of patients with adult T-cell leukemia/lymphoma in Brazil: analysis of infection transmission.

We examined the presence of HTLV-I infection among 66 family members of 13 patients with well documented ATL to investigate the routes of HLTV-I transmission in a Southeast region of Brazil. HTLV-I infection was screened by an enzyme immunossay (ELISA) test and all repeatedly positive or indeterminate ELISA samples were further tested by a Western-Blot (WB) technique. Indeterminate and inconclusive WB samples were confirmed by a polymerase chain reaction (PCR). ELISA results showed that 40 (60.6%) individuals were not infected; 16 (24.2%) were positive; and 10 (15.2%) were undetermined. Among 16 ELISA positive subjects, 14 (87.5%) were confirmed to be positive by WB while 2 (12.5%) showed inconclusive results. Based on the laboratory data, questionnaire analysis, and family/epidemiological studies, we concluded that HTLV-I vertical transmission occurred in 6 of the 13 families. In 3 of these 6 families, the horizontal transmission also could be demonstrated. An isolated horizontal transmission was detected in one family, and in 6 families we did not find any infected family member. All HTLV-I-infected persons were clinically asymptomatic. The occurrence of an effective HTLV-I vertical transmission detected by the present study suggest that HTLV-I infection is endemic in the Southeast region of Brazil. Consistent with the modes of transmission, the HTLV-I antibody seroprevalence was greater in relatives of ATL patients than in the general blood donor Brazilian population (0.4%). In addition, the present data suggest that HTLV-I carries a high infectivity rate but a low virulence.

Adolescent↗
PubMed1996

The relationship between megacolon and carcinoma of the colon: an experimental approach.

'Carcinoma of the colon does not occur in cases of megacolon' is an axiom held by Brazilian physicians working in endemic areas for Chagas' disease. The objective of the present study was to test this axiom experimentally by submitting rats with experimental megacolon to a carcinogen which causes carcinoma of the colon. Eighty young male Wistar rats received serosal application of either saline (0.9% NaCl) or 2 mM benzalkonium chloride (BAC) to the distal colon. Ten months later randomly chosen saline and BAC rats were injected weekly with dimethylhydrazine (DMH) for 20 weeks. Non-DMH-treated rats from both original groups were maintained, for a total of four experimental groups. Three months after the injections all surviving rats were killed. At autopsy the presence of absence of carcinomas along the colon was recorded. The induction of megacolon was evaluated by morphometry of the wall from the distal colon and myenteric denervation was assessed by neuron counts. An increase of at least 2-fold in distal colon wall thickness confirmed the induction of megacolon in BAC-treated rats. Neuronal counts from BAC and control rats not treated with DMH showed an average denervation of 63%. The number of distal colon carcinomas in BAC+DMH-treated rats was significantly lower than that in DMH-treated rats. These findings appear to contradict the traditional concept of carcinogenesis of the colon. The clinical axiom was reproduced experimentally.

1,2-Dimethylhydrazine↗
PubMed1995

Experimental megaileum.

Typical megaileum occurred in young male Wistar rats three months after ileum myenteric plexus denervation. An average of 58.4% denervation of the Auerbach plexus was obtained by serosal application of benzalkonium chloride (0.2% v/v). Denervation was assessed by ganglion cell counts in an 8 nm ring-shaped histological sectfrom the midportion of the treated segment. A morphometric study showed that the increased thickness of the megaileum wall was due to muscle hypertrophy and mucosal hyperplasia. The potential usefulness of this model of megaileum is emphasized.

Animals↗
PubMed1995

Peripheral and coronary sinus catecholamine levels in patients with severe congestive heart failure due to Chagas' disease.

The aim of this study was to assess the peripheral and cardiac autonomic system by catecholamine measurements in patients with severe chagasic and nonchagasic heart failure. Fifteen chagasic and 16 nonchagasic patients were enrolled in the study. Plasma venous norepinephrine levels (pg/ml) were 397.26 +/- 250.11 for chagasic and 660.05 +/- 455.57 for nonchagasic patients (p > 0.05), plasma venous epinephrine levels 215.84 +/- 254.04 for chagasic and 106.17 +/- 65.90 for nonchagasic patients (p > 0.05), aortic root norepinephrine levels 435.46 +/- 306.60 for chagasic and 668.16 +/- 512.82 for nonchagasic patients (p > 0.05), aortic root epinephrine levels 300.33 +/- 302.69 for chagasic and 199.98 +/- 162.88 for nonchagasic patients (p > 0.05), coronary sinus norepinephrine levels 636.10 +/- 495.22 for chagasic and 552.17 +/- 535.54 for nonchagasic patients (p > 0.05) and coronary sinus epinephrine levels 226.66 +/- 277.47 for chagasic and 69.21 +/- 35.62 for nonchagasic patients (p = 0.02). Myocardial and peripheral norepinephrine and epinephrine extractions were similar for both groups. Taken together, these findings may suggest that chagasic patients with congestive heart failure have biochemical evidence of cardiac autonomic dysfunction with preservation of the peripheral sympathetic activity.

Adolescent↗
PubMed1995

Effect of sorghum grain processing on site and extent of digestion of starch in lactating dairy cows.

Four lactating Holstein cows, fitted with T-type cannulas in the proximal duodenum were used in a 4 x 4 Latin square design to study the effects of sorghum grain processing on site of digestion of nutrients. Diets were steam-rolled corn, dry-rolled sorghum, steam-flaked sorghum, and an equal mixture of steam-flaked and dry-rolled sorghum as 43% of DM in a TMR (35:65, ratio of forage to concentrate). Intake and duodenal starch for all diets averaged 6.8 and 2.1 kg/d. Apparent total tract and ruminal digestibilities of starch for the respective diets averaged 81, 60, 70, and 60 and 97, 85, 91, and 89%. Starch digestibilities in the intestine were higher for steam-flaked than for dry-rolled or mixed sorghum (83 vs. 63 and 61%). Consistent with less postruminal passage of starch, cows fed steam-flaked sorghum had higher fecal pH than did cows on other treatments. No effects of diet occurred on NDF or ADF digestibilities. Compared with dry rolling of sorghum, steam flaking increased the digestibility of starch in the rumen from 60 to 81% and in the small intestine from 63 to 83%, increasing digestible starch intake 9% (6.4 vs. 5.9 kg/d). Values for steam-rolled corn were intermediate. Microbial protein in the rumen was not significantly altered by diet.

Animal Feed↗
PubMed1994

Cardiac noradrenaline in experimental rat envenomation with Africanized bee venom.

The concentration of cardiac tissue noradrenaline (NOR) was determined in Wistar rats injected with 1.5 microliters/100 g body weight Africanized bee venom (ABV) (LD50 = 0.8 microliter/100 g body weight by the intravenous route). The animals were injected with ABV by the intramuscular (IM), intraperitoneal (IP), subcutaneous (SC) and intravenous (IV) routes. Animals injected by the IM, IP and SC routes were sacrificed 4, 7 and 24 hours after injection. The animals injected by the IV route were sacrificed when they became apnoeic (within minutes). NOR levels in animals injected by the IM, IP and SC routes were inconstant and inconclusive. In contrast, animals injected with ABV by the IV route showed a significant decrease in NOR concentration when compared to their respective controls, suggesting tissue NOR release. It is suggested that the mechanism of death of the animals injected IV with ABV seems to be related, at least in part, to functional cardiac alterations secondary to stress-induced NOR release. As a consequence, cardiological monitoring of patients who are victims of multiple bee stings is recommended, together with a judicious evaluation of therapy involving drugs with a sympathomimetic action.

Animals↗
PubMed1994

Noninvasive predictors of mortality for patients with Chagas' heart disease: a multivariate stepwise logistic regression study.

This prospective investigation was conducted in an attempt to identify noninvasive predictors of mortality for patients with Chagas' heart disease through a multivariate stepwise logistic regression study. Fifty-six patients with a positive complement fixation test for Chagas' disease were followed up at the Cardiomyopathy Clinic of our institution from April 1990 to April 1992. Patient age was 59 +/- 17 years; 28 (50%) were male. Upon admission, 19 patients (33%) were in the New York Heart Association (NYHA) class III and 8 (14%) in the NYHA class IV. Systolic blood pressure was 125 +/- 23 mm Hg, diastolic blood pressure 76 +/- 11 mm Hg and resting heart rate 77 +/- 11 beats/min. Forty patients (71%) were given digitalis and 39 (69%) angiotensin-converting enzyme inhibitors. Plasma Na+ was 140 +/- 4 mEq/l, K+ was 4.34 +/- 0.73 mEq/l and creatinine level 1.34 +/- 0.31 mg/100 ml. Cardiomegaly was observed in the chest X-ray of 41 of 51 (79%) available patients. Atrial fibrillation was observed in the resting ECG of 24 of 54 (44%) available patients, premature ventricular contractions in 23 (41%), right bundle branch block in 26 (46%) and left anterior hemiblock in 26 (46%) patients. Echocardiography revealed a left ventricular ejection fraction of 0.45 +/- 0.16, left ventricular systolic dimension of 51.23 +/- 13.53 mm and left ventricular diastolic dimension of 62.94 +/- 19 mm. Sixteen (28%) patients died during the 2-year study, 11 of them suddenly.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1993

Clinical and morphological characteristics associated with sudden cardiac death in patients with Chagas' disease.

The medical records of 24 patients with Chagas disease who died suddenly, between 1982 and 1988, were examined in an attempt to determine the clinical profile of sudden death in Chagas disease. Patient age ranged from 33 to 72 years (average: 51). Seventeen (70%) were male: Five (20%) were asymptomatic. Dyspnoea at rest was observed in 16 (66%) and palpitations in eight (33%). On physical examination, arrhythmias were observed in 14 (58%), ankle swelling in 13 (54%) and liver enlargement in 12 (50%) patients. Twenty-three (95%) patients had an abnormal resting electrocardiogram: ventricular premature contractions were observed in 19 patients (79%) and a left anterior fascicular block in 14 (58%). The chest X-ray revealed cardiomegaly in 20 patients (82%), which was moderate in three (13%) and severe in 11 (45%). At autopsy, mean heart weight was 496 g. Dilatation of all cardiac chambers was detected in 22 (91%), and apical aneurysm in 19 (79%) patients. When compared with symptomatic patients, asymptomatic patients with Chagas disease had a higher frequency of normal physical examination (3/5 vs 1/19, P < 0.004), normal chest X-ray (3/5 vs 1/19, P < 0.01), and a lower heart weight (400 +/- 43 g vs 521.58 +/- 146.26 g, P < 0.03). The majority of patients with Chagas disease who die suddenly have severe underlying myocardial disease. In some of them, however, sudden cardiac death may occur in the presence of minimal, if any, heart involvement.

Adult↗
PubMed1993

Giant aneurysm of the ascending aorta secondary to medial agenesis in infancy.

A 14-month-old infant was found to have a giant aneurysm of the ascending aorta at the time he underwent angiography. At the time of autopsy, a saccular chamber was found to take the place of the aorta. Histologic examination of the aneurysm revealed absence of the medial layer. Thus, medial genesis may be another cause of aneurysm of the ascending aorta.

Aorta↗
PubMed1991

Cardiac levels of norepinephrine, dopamine, serotonin and histamine in Chagas' disease.

Extraction and measurement of biogenic amines (norepinephrine, dopamine, serotonin and histamine) were carried out on human ventricular myocardium obtained from autopsies of individuals divided in the three following groups: chronic Chagas' heart disease (with congestive heart failure: 16 cases, and with sudden and unexpected death: 13 cases); hypertensive heart disease (12 cases); and control patients (with no heart disease: 12 cases). The myocardial samples were obtained from the free walls of left and right ventricles and from the apex. A significant depletion of norepinephrine was detected in those with congestive failure. A poorly elevated level of dopamine was also seen in right ventricular and apical myocardium from those with failure. Left ventricular and apical concentration of serotonin were significantly elevated in the presence of hypertensive heart disease. The most important findings were obtained with histamine, which is increased in both groups of Chagasic patients. We believe that the approach here reported may provide useful informations on the pathogenetic mechanisms, thus far poorly understood, of chronic Chagas' heart disease.

Adult↗
PubMed1991

Changes in electrocardiographic patterns at different stages of Chagas' heart disease in rats.

1. The resting electrocardiogram was obtained from 25 Trypanosoma cruzi-infected rats 30 days after infection (phase I). The resting electrocardiogram was abnormal in 12 (group I) and normal in 13 (group II) animals. Nineteen similar but non-infected animals served as controls. Both the resting electrocardiogram and the ajmaline test were performed 120 and 350 days after infection (phases II and III, respectively). 2. With regard to the resting electrocardiogram of group I animals, left axis deviation was found in 10 of 12 (83%) in phase I, one of 12 (8%) in phase II (P less than 0.05) and in none of phase III (P less than 0.05). An intraventricular conduction delay was found in four of 12 (33%) rats in phase I, two of 12 rats (16%) in phase II (P greater than 0.05) and six of 12 rats (50%) in phase III (P greater than 0.05). The ajmaline test was abnormal in nine of 10 (90%) rats of group I with normal resting electrocardiogram in phase II, and in three of six (50%) animals in phase III (P greater than 0.05). 3. An intraventricular conduction delay was found in the resting electrocardiogram of one of 13 (7%) rats of group II in phase III. The ajmaline test was abnormal in one of 13 (7%) rats in phase II and in one of 12 (8%) rats in phase III. 4. No control rat showed pathological changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Ajmaline↗
PubMed1991

The chronological relationship between the thickening of smooth muscle, epithelial cell proliferation and myenteric neural denervation in the rat jejunum.

The jejunum of rats was treated by serosal application of a 0.2% solution of benzalkonium chloride (BAC) for 30 min. Control animals were treated with saline (0.9% NaC1). The animals were allocated to eight groups of 10 rats each and sacrificed 15, 30, 45, 60 days after BAC treatment. Segments were removed from the jejunum for neuronal counting, measurement of the smooth muscle area and morphokinetic study of the epithelium. There was a significant reduction in neuron number in the myenteric plexus 30 days after BAC treatment, thickening of smooth muscle 15-60 days after BAC treatment, but no change in epithelial cell proliferation in the jejunum at either time.

Animals↗
PubMed1990

Effects of long term metoprolol administration on the electrocardiogram of rats infected with T cruzi.

STUDY OBJECTIVE: The aim of the study was to evaluate the role of beta receptor antagonists in the evolution of experimental Chagas' disease. DESIGN: Rats were infected with T cruzi, 2000 parasites.g-1 body weight, soon after weaning. One group was then given metoprolol, 100 mg.kg-1.d-1, in drinking water. A comparison group received no metoprolol. Two control groups of non-infected rats were also studied, one with and one without metoprolol in the same dose. SUBJECTS: Adult male albino rats were used: 144 were infected with T cruzi and received metoprolol (group IM), 137 were infected and received no metoprolol (group IW), 46 non-infected rats received metoprolol (group CM), and 43 non-infected rats did not receive metoprolol (group CW). MEASUREMENTS and main results--30 d after infection, resting ECG was performed in all surviving rats. (There were 63 deaths in the infected groups and none in the non-infected groups.) Abnormal ECG was found in 20/81 infected rats in group IM and in 30/74 in group IW (p less than 0.05). No ECG changes were found in the non-infected rats. Of rats in group IM with normal resting ECG, 31 continued to take metoprolol (group IMNM), while 30 similar rats did not (group IMNW); in group IM with abnormal ECG, 10 rats continued to take metoprolol (group IMAM), while 10 similar rats did not (group IMAW). Of rats in group IW with normal ECG, 22 were started on metoprolol (group IWNM), while 22 similar rats were not (group IWNW); in group IW with abnormal ECG, 15 rats were started on metoprolol (group IWAM), while 15 similar rats did not (group IWAW). After 120 d and 300 d infection there were no differences in mortality rate and Ajmaline test in any of the matched groups (IMNM X IMNW; IMAM X IMAW; IWNM X IWNW; IWAM X IWAW). After 120 d there was no difference in ECG between the groups, but after 300 d there was a decrease in abnormal ECG in group IWAM (IWAM v IWAW, 0/12 v 5/12, p less than 0.05). No histological differences were found. CONCLUSIONS: Metoprolol decreases the proportion of rats with abnormal resting ECG in both the acute and the chronic stage of T cruzi infection.

Animals↗
PubMed1990

Megacolon in rats.

Four months of sigmoid colon intrinsic denervation of young male Wistar rats resulted in typical megacolon. Average 46.0% denervation of the Auerbach plexus was obtained by serosal application of benzalkonium chloride (0.2% v/v). Denervation was assessed by ganglion cell counts in a 480-nm extension of the treated segment. Increased thickness of the megacolon wall was due to muscle hypertrophy (+117.4%) and mucosal hyperplasia (+53.9%) as shown by morphometry. The potential usefulness of this experimental model is emphasized.

Animals↗