Search PubMed⌕ Search

Biomedical subjects

C B Pereira

Publications and source records attributed to C B Pereira.

At least 37 records · Page 2Linked to original sources
PubMed1984

Exercise testing in the latent phase of Chagas' disease.

Exercise stress testing was performed in 50 completely asymptomatic patients in the latent phase of Chagas' disease. In 32 (64%) abnormalities were found consisting of either abnormal ST depression, exercise-induced arrhythmias, or chronotropic incompetence. The latter was determined by comparing the heart rate response to 50 age- and sex-matched control patients without serologic evidence of Chagas' disease. In the absence of an adequate control population we can only speculate as to the significance of the ST depression and arrhythmias during exercise. However, chronotropic incompetence may be a specific marker for Trypanosomal infestation in an endemic area. It probably is an early manifestation of autonomic dysfunction secondary to Chagas' disease.

Adult↗
PubMed1984

Inhibition of aflatoxin B1 carcinogenesis in rainbow trout by flavone and indole compounds.

Several compounds such as flavonoids, selenium, antioxidants and retinoids reportedly reduce the induction of cancer in experimental animals, and some have been suggested to function by affecting the mixed-function oxidase (MFO) system. The following compounds: 50 and 500 p.p.m. beta-naphthoflavone (BNF), 1000 p.p.m. flavone, 1000 p.p.m. of a tangeretin - nobilitin mixture, 1000 p.p.m. beta- ionone , 1000 p.p.m. indole-3-carbinol ( I3C ) and 2000 p.p.m. quercetin were examined for protection against aflatoxin B1 (AFB1) hepatocarcinogenesis, induction of the MFO system and metabolism of AFB1 in rainbow trout. These compounds were fed to fingerling rainbow trout for 8 weeks. At that time the activity of several MFO enzymes and cytochrome P450 content were measured and the trout were exposed for 2 weeks to 20 p.p.b. AFB1 in the same diets. After feeding the test diets without AFB1 for another 6 weeks and basal diet for another 52 weeks, the tumor incidence was determined. The effect of BNF and I3C on in vivo binding of AFB1 to DNA was also measured in separate groups of trout. BNF induced the trout MFO system in a dose-dependent manner, tangeretin - nobilitin was less effective and I3C did not induce. BNF showed significant alterations in the metabolism of AFB1 to aflatoxicol and aflatoxin M1 using cell fractions from pretreated fish. None of the other compounds, including I3C showed such an effect. Despite the apparent lack of in vitro effect of I3C , both BNF and I3C reduced AFB1 - DNA binding in vivo. I3C and BNF provided marked protection against AFB1-induced hepatocarcinogenesis, while the other compounds were less effective. The 58 weeks tumor incidences were 4% for 1000 p.p.m. I3C , 6% for 500 p.p.m. BNF and 18% for 50 p.p.m. BNF, compared to 38% for the AFB1-positive control. These data demonstrate that gross induction of the MFO system was not necessarily required for alterations in DNA adduct formation in vivo or protection against AFB1 carcinogenesis. Both BNF and I3C provided marked protection but only BNF induced the MFO system.

Aflatoxin B1↗
PubMed1983

Electrophysiologic findings in long-term asymptomatic chagasic individuals.

Under electrophysiologic studies, 44 asymptomatic chagasic individuals were studied. The mean age was 39.9 years, with 26 being male. The surface ECG showed normal tracings in 12 patients, left anterior fascicular block in three, incomplete right bundle branch block in two, and right bundle branch block in 27 (isolated in six, associated with left anterior fascicular block in 19 and with left posterior fascicular block in two). Sinus nodal dysfunction was found in eight (18.1%), and 29 (66%) presented with some form of abnormal AV nodal behavior during atrial stimulation. Repetitive ventricular beats were recorded in 17 (41.4%) patients. Finally, in 19 (43.1%), patterns of dysfunction at two or more levels of the cardiac conducting system were found. It is concluded that the chagasic cardiomyopathy produces diffuse lesions in the conducting tissue of the human heart in the stages when the disease is detected, and that the individuals are still asymptomatic.

Adult↗
PubMed1977

The craniofacial pattern of the Lengua Indians of Paraguay.

Lateral cephalometric headfilms of 30 male and 30 female Lengua Indians taken in the Chaco area of Paraguay were compared with a sample of 23 male and 25 female South African Caucasoids with excellent occlusion. The most obvious difference noted between the two population groups was the degree of prognathism evident in the Lengua. This was attributed to the generally shorter anterior cranial base in the latter group rather than to the size or forward positioning of their jaws. The significantly larger ANB (Subspinale, Nasion, Supramentale) angle observed in the Lengua was attributed to one or both of two factors, namely, the short anterior cranial base or the clockwise rotation (forward tipping) of the jaws relative to the anterior cranial base. Chinpoint position relative to the anterior cranial base in the Lengua is not much different from that of our Caucasoid sample. The lower incisor teeth in the Lengua, but not the upper ones, are more labially inclined than those of the Caucasoids.

Adolescent↗
PubMedDate not supplied

Carcinogenicity of dietary dimethylnitrosomorpholine, N-methyl-N'-nitro-N-nitrosoguanidine, and dibromoethane in rainbow trout.

Eighteen-mo feeding trials of rainbow trout were used to test the carcinogenicity of 5 chemicals in this species. A single exposure level was used for each substance. The doses and chemicals tested were 1,556 ppm 2,6-dimethylnitrosomorpholine (DMNM), 500 ppm N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), 2,000 ppm 1,2-dibromoethane (DBE), 2,000 ppm 1,1-dichloroethylene (DCE), and 200 ppm cyclophosphamide (CP). Liver and/or glandular stomach neoplasms were produced by DMNM (liver and stomach), MNNG (stomach), and DBE (chiefly, stomach tumors). In addition, DMNM produced a low incidence of swimbladder papillomas and caused testicular atrophy in 50% of treated males. DCE and CP produced no neoplasms at the exposure levels used. No evidence of other chronic toxicity was seen for any of the 5 compounds.

Animal Feed↗