PubMed Health⌕ Search

Biomedical subjects

J A Souza

Publications and source records attributed to J A Souza.

At least 19 recordsLinked to original sources
PubMed2005

Method for analyzing second-order phase transitions: application to the ferromagnetic transition of a polaronic system.

A new method for analyzing second-order phase transitions is presented and applied to the polaronic system La(0.7)Ca(0.3)MnO3. It utilizes heat capacity and thermal expansion data simultaneously to correctly predict the critical temperature's pressure dependence. Analysis of the critical phenomena reveals second-order behavior and an unusually large heat capacity exponent.

Journal Article↗
PubMed2000

Evaluation of the areas of neuronal cell bodies and nuclei in the myenteric plexus of the duodenum of adult rats.

This study compared the areas of cell body and nucleus profiles of the myenteric neurons in the antimesenteric and intermediate regions of the duodenum of adult rats. Five male rats were used. The duodenum was removed and dissected to whole-mount preparations, which were stained by the Giemsa technique. The areas of cell body and nucleus profiles of 100 neurons, 50 from each region, of each animal, were assessed with image analyser. Based on the global mean+/-SD of the areas of cell body profiles, neurons were labelled as small, medium or large. It was observed that the neurons did not differ significantly in size or incidence between the antimesenteric and intermediate regions. However, the nuclei of the small and medium neurons were significantly smaller in the latter region. It is discussed that the smaller nuclear size could be related to the cell bodies being slightly smaller on this region and to a possible smaller biosynthetic activity which would influence nuclear size.

Animals↗
PubMed1998

Effect of dietary fat on lymphocyte proliferation and metabolism.

The effect of diets enriched with fat containing different fatty acids on glucose and glutamine metabolism of mesenteric lymph nodes lymphocytes, spleen, and thymus and lymphocyte proliferation was examined. The following fat-rich diets were tested: (1) standard chow (CC); (2) medium chain saturated fatty acids (MS)--coconut fat oil; (3) long chain saturated fatty acids (LS)--cocoa butter; (4) monounsaturated fatty acids (MU)--canola oil (n-9); (5) polyunsaturated fatty acids (PU)--soybean oil (n-6). Of the fat-rich diets tested, MS was the one to present the least pronounced effect. Lymphocyte proliferation was reduced by LS (64 per cent), MU (55 per cent), and PU (60 per cent). Hexokinase activity was enhanced in lymph node lymphocytes by PU (67 per cent), in the spleen by MS (42 per cent), and in the thymus by PU (30 per cent). This enzyme activity was reduced in the spleen (33 per cent) by LS and MU (35 per cent). In the thymus, this enzyme activity was reduced by LS (26 per cent) and MU (13 per cent). Maximal phosphate-dependent glutaminase activity was raised in lymphocytes by MS (70 per cent) and MU (20 per cent). This enzyme activity, however, was decreased in lymphocytes by PU (26 per cent), in the spleen by LS (15 per cent), and in the thymus by MU (44 per cent). Citrate synthase activity was increased in lymphocytes by MU (35 per cent), in the spleen by LS (56 per cent) and MU (68 per cent), and in the thymus by LS (42 per cent). This enzyme activity was decreased in lymphocytes by PU (24 per cent) only. [U-14C]-Glucose decarboxylation was raised by all fat-rich diets; MS (88 per cent). LS (39 per cent), MU (33 per cent), and PU (50 per cent), whereas [U-14C]-glutamine decarboxylation was increased by LS (53 per cent) and MU (55 per cent) and decreased by MS (17 per cent). The results presented indicate that the reduction in lymphocyte proliferation due to LS, LU and PU could well be a consequence of changes in glucose and glutamine metabolism.

Animals↗
PubMed1998

Fish oil given by gavage increases lymphocyte proliferation and production of hydrogen peroxide by rat macrophages.

1. The effect of fish oil (FO) administration by gavage (0.4% body weight) on macrophage and lymphocyte function was investigated in young male rats. The results were compared with those obtained by administration of soybean oil (SB) and cocoa butter (CB). 2. Lymphocyte proliferation was markedly increased by FO administration compared with control and other oils. 3. Macrophage phagocytosis capacity was not affected by FO, but it was increased by CB and SB. 4. The oils did not affect the production of O2.- but increased the production of H2O2 in the presence of PMA. 5. The administration of the oils did not markedly affect the activity of antioxidant enzymes in macrophages, except for a decrease in superoxide dismutase activity by FO.

Animals↗
PubMed1997

[Predictors of hospital mortality in the thrombolytic era for acute myocardial infarction in Salvador, State of Bahia, Brazil].

PURPOSE: To determine the cumulative incidence and risk factors of in-hospital death due to acute myocardial infarction (AMI) in the thrombolytic era and to assess the degree of incorporation of new therapeutical interventions to the treatment of AMI in Salvador, Brazil. METHODS: A retrospective study based on medical records of 388 patients hospitalized with an AMI in different hospitals between January 1993 and December 1994. The relative risk (RR) was used as a measure of association for the unadjusted analysis. To control for possible confoundears and to assess interactions, odds ratios (OR) were used to estimate the RR, by logistic regression models. RESULTS: During the hospitalization period 50 (12.9%) patients died. The main predictors of hospital mortality in the unadjusted comparisons were older age (age > 60 years) (RR = 2.76; p < 0.01), female gender (RR = 2.08; p = 0.01), Killip class > 1 (RR = 5.73; p < 0.01), anterior wall AMI (RR = 1.92; p = 0.02), previous stroke (RR = 4.13; p < 0.01) and systemic disease (RR = 2.76; p < 0.01). In the multivariate analysis, older age (OR = 2.42; p = 0.02), Killip class > 1 (OR = 7.14; p < 0.01), anterior wall AMI (RR = 2.37; p = 0.02) and previous stroke (RR = 2.34; p = 0.04) were the main independent predictors of hospital death. Thrombolytic therapy was used in 143 patients (36.8%), aspirin in 322 (83%), beta blockers in 204 (52.6%) and heparin in 248 (63.9%). Cardiogenic shock was responsible for more than half of the death cases. CONCLUSION: Based on the data presented, older age, Killip class and anterior wall infarction are still important predictors of death due to AMI in the thrombolytic era, confirming other studies.

Aged↗
PubMed1995

Antibody response after immunization of Brazilian children with serogroup C meningococcal polysaccharide noncovalently complexed with outer membrane proteins.

We have studied the antibody response of Brazilian vaccinees to C meningococcal polysaccharide (C-PS) after one or two doses of a vaccine composed of C-PS, outer membrane proteins of B meningococci and aluminum hydroxide. Total IgG, IgG1 and IgG2 as well as bactericidal activity mediated by complement were measured in serum samples from children 3 to 83 months of age (post-vaccination IgG, IgG1 and IgG2 levels of 2.4 to 13.4 micrograms/ml; less than 18 to 67.8 U/ml and less than 18 to 106.8 U/ml, respectively) and from individuals 10 to 14 years of age (post-vaccination IgG, IgG1 and IgG2 levels of 14.6 micrograms/ml, 23.7 U/ml and 112.0 U/ml, respectively). The antibody response, measured as IgG levels, was age-dependent. Although high antibody levels were demonstrable by enzyme-linked immunosorbent assay (ELISA), bactericidal activity was not demonstrable (less than 1:4) in serum from children aged less than 24 months. A significant bactericidal activity was detected in serum of children older than 49 months of age and in individuals 10 to 14 years of age. A predominance of IgG2 was observed in post-vaccination serum samples from children belonging to those two age groups. The antibody concentration sufficient to confer protection as well as the possible causes of the poor correlation observed between ELISA and bactericidal activity results are discussed.

Adolescent↗
PubMed1993

[Percutaneous retrieval of intravascular foreign bodies].

PURPOSE: To report our experience on percutaneous vascular foreign body retrieval and to analyse current techniques employed. METHODS: From 1985 to 1991, 15 (0.18%) of 7,963 procedures performed in the Cardiac Catheterization Laboratory-Hospital São Paulo were intravascular foreign body retrieval: 9 (60%) intracath, 4 (26.8%) diagnostic catheters, one Swan Ganz catheter entrapped at superior cava vein and one fragment of angioplasty guide-wire in the circumflex branch of the left coronary artery. The snare technique was used in 11 cases, a endomyocardial bioptome device in 1 case and modified snare technique for the intracoronary wire fragment retrieval was used in 1 case. In two cases of embolized fragment in peripheral arteries, no attempt was done for retrieval. RESULTS: All (100%) of the 13 attempted procedures were successful. The two foreign bodies not removed had an uneventful follow-up. CONCLUSION: The snare technique for percutaneous retrieval of intravascular foreign bodies is safe and has excellent results. The management peripheral fragments is not well defined yet.

Adult↗
PubMed1992

[Angioplasty in native coronary circulation in patients treated with myocardial revascularization].

PURPOSE: To evaluate the clinical results after angioplasty in the native coronary vessels in patients who had undergone previous coronary artery surgery. METHODS: From June 1987 to July 1990, 69 patients with previous coronary artery surgery underwent coronary angioplasty in the native arteries. Age ranged from 31 to 82 (mean = 57.5) years, fifty eight were males. Angina was present in all patients. The patients were classified in three groups according to the following criteria: group I--incomplete revascularization following bypass surgery (28 patients); group II--progression of the disease in ungrafted vessels (24 patients) and group III--progression of the disease in grafted vessels (17 patients). RESULTS: Primary success was achieved in 94% (65/69). Ninety-five percent in group I, 92% in group II and 94% in group III. Complications occurred in 4%; emergency surgery or deaths were not observed in this study. Forty patients (61%) repeated coronary arteriography an average follow-up of 4 months and restenosis was detected in 10 (25%); 8 of them were redilated. Survival rates was 95% and 75% of them were free of coronary events after an average follow-up of 13 months. CONCLUSION: Coronary angioplasty in these patients is a safe and effective interventional procedure in the treatment of coronary artery disease in native coronary vessels.

Adult↗
PubMed1991

[Coronary angioplasty in young patients].

PURPOSE: To evaluate the results of coronary angioplasty in patients at the age of 40 years old or under. METHODS: From July 1987 to July 1990, 878 coronary angioplasty procedures were performed. Sixty six patients (7.5%) were 40 years old or under. The coronary obstruction was considered significant when 70% or more of the arterial diameter was involved and the post angioplasty results were considered satisfactory when residual obstruction was less than the 50%. RESULTS: Fifty four patients (81.8%) were male with an average age of 37 years (ranging from 29 to 40). Forty four patients (67%) had stable angina, 18 (27%) unstable angina, 3 (4%) acute myocardial infarction (AMI) and one (1.5%) AMI after streptokinase treatment. Eight of these patients had previous report of AMI and 3 (4.5%) had undergone coronary bypass grafting surgery. Fifty five patients (83%) had single vessel disease and 11 (17%) had multivessel disease. Eighty coronary arteries had balloon dilatation. In 32 patients (58%) with single vessel artery, 12 (22%) in the RCA, 10 (18%) in the left circumflex and one (2%) into a saphenous vein bypass grafting. In 12 patients (48%) with multivessel disease it was performed in the LAD coronary artery, 8 (32%) in the RCA and 5 (20%) in the left circumflex. Angioplasty was successfully performed in 53 (96%) patients with single vessel disease and in 10 (01%) with multivessel disease. One of the patients died immediately after the procedure. A follow up of 11.6 months (ranged from 1 to 27 months) was possible in 63 patients. Re-stenosis was depicted in 10 (19%) of the 55 patients with single vessel disease and in 3 of the 11 patients (30%) with multivessel disease. Nine patients had a successful redilatation in the first group and 2 in the second one. The two remaining patients had undergone coronary bypass surgery. The clinical evaluation among patients who had been dilated as the first procedure and those who had redilatation (61 patients) showed: 92% were asymptomatic and 8% had mild angina. CONCLUSION: Coronary angioplasty performed in young patients is an effective procedure with very low rate of early complications and favorable clinical follow-up.

Adult↗
PubMed1984

Concentration of vitamin A in the liver of foetuses and infants dying of various causes in Brasilia, Brazil.

The vitamin A concentration in liver samples taken at autopsy from the central portion of the right lobe of 57 infants 0-1 year old was determined by a dual spectrophotometric and colorimetric assay. Death was due to respiratory disease (30%), complications of premature birth (16%), infections (14%), hemorrhage (14%), pneumonia (10%), cerebral edema (7%), and miscellaneous causes (9%). Gross malnutrition was noted in only 2 of these children. The median vitamin A concentration was 61 micrograms of retinol/g liver, with a range of 6-293 micrograms/g. The percent distribution of liver vitamin A levels in micrograms/g was: less than 5 (0%); 5-10 (7%); 10-20 (5%); 20-40 (16%); 40-80 (42%); 80-120 (14%); greater than 120 (16%). The mean liver level in 9 stillborn full-term infants (60 micrograms/g) was markedly lower than in 7 stillborn premature infants (125 micrograms/g). The median value for 22 infants from indigent families (54 micrograms/g) was lower than that of 35 infants from non-indigent families (65 micrograms/g). By applying the criteria that liver reserves of vitamin A less than or equal to 5 micrograms retinol/g of liver indicate a high risk of vitamin A deficiency and those less than 20 micrograms retinol/g of liver denote an inadequate reserve, no infant was at high risk but 12% had insufficient reserves.

Brain Edema↗
PubMed1975

[Experimental trial to reproduction enzootic haematuria in cattle by feeding bracken fern [Pteris aquilina (Kuhn)] (author's transl)].

Cattle were fed with a diet containing bracken fern in order to study the development of chronic bovine haematuria. The experimental 25 animals were randomly divided into 5 groups and such groups received different amounts of the plant. All groups were fed for 36 months, while no clinical effect of the disease was noted. After that time, the supplement of bracken fern to the diet was suspended and the animals still remained under observation. One of the animals (from group I) exhibit haematuria one month after the fern was removed from the diet. In the same occasion, four animals were slaughtered and only one of them presented haemorragic lesions in the urinary bladder. After 34 days another four animals were slaughtered and 114 days later three more were killed. All animals were chosen randomly and in spite of no clinical signs of the disease, all of them presented haemorragic lesions in the urinary bladder. The results obtained in this experiment confirmed that bracken fern (Pteris aquilina) is responsable for the development of chronic bovine haematuria in cattle. The disease is challenged by continuous ingestion of small amounts of bracken fern during a long period of time.

Animals↗