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Biomedical subjects

S Vieira

Publications and source records attributed to S Vieira.

At least 37 records · Page 2Linked to original sources
PubMed1995

Reversed metal replicas of freeze-dried proteins to be visualized with the scanning tunneling microscope.

Scanning tunneling microscopy of metal-coated specimens has become a reliable technique that permits direct three-dimensional visualization of structural details at a level at which individual subunits in protein complexes or even single domains of proteins can be resolved. We describe in this paper a variation of the freeze-drying metal coating procedure that allows us to image with the STM the inner side of the metal replica, previously in contact with the protein molecules. We have tested this new approach with two different well characterized protein systems: freeze-dried two-dimensional crystals of bacteriophage phi 29 connector and the vesicle form of two-dimensional crystals of cytochrome oxidase from beef heart mitochondria. The images obtained have very good contrast and provide direct topographic information of the crystal surface, complementing structural information obtained previously with transmission electron microscopy. The resolution limit is imposed by the size (2-3 nm diameter) and corrugation of the metal grains used to prepare the replica and by the randomness of the metal shadowing.

Aluminum Silicates↗
PubMed1995

[Myocardial revascularization in left coronary trunk lesion in patients over 65 years old].

PURPOSE: To study the short and long-term follow-up of patients with left main coronary artery disease (LMCAD) and age over 65 years, by comparing the results with patients under 65 years-old. METHODS: Twenty-two patients with LMCAD and mean age of 69 +/- 3.5 years (group I) were underwent isolated coronary artery bypass grafting (CABG) and compared to 31 patients with LMCAD, mean age of 54 +/- 7 years (group II), who also underwent isolated CABG. The life-table Kaplan-Meyer method was used to estimate the post-operative survival. The chi-square and Student "t" test were used when necessary. RESULTS: Despite higher operative mortality in group I (9.1% x 3.2%), the difference was statistically not significant. The operative morbidity was similar in both groups. Actuarial survival at 4 years was 85% in group I and 95% in group II. Actuarial survival free of cardiac events was 69% in group II and 75% in group II. CONCLUSION: The CABG is well tolerated and had low morbidity and acceptable mortality in old patients with LMCAD. The long-term survival in these patients was very similar to the younger patients.

Actuarial Analysis↗
PubMed1989

Cytoproteic CSF findings in 33 MS patients: usefulness for diagnosis.

Although multiple sclerosis (MS) is mainly defined on clinical grounds, CSF parameters still remain important diagnostic and scoring tools. To demonstrate the usefulness of some easy laboratory techniques, a CSF cytomorphological and agarose gel electrophoresis (AGE) evaluation was undertaken in 33 MS patients: 79% presented a lymphoid cell profile and in 73% the gamma globulin fraction was abnormal. In the great majority of cases (97%) either or both cytological and electrophoretical abnormalities were found.

Adolescent↗
PubMed1979

[Effects of parotidectomy on the blood sugar level and hepatic glycogen (author's transl].

This work was carried out in order to investigate the influence of parotid glands on the metabolism of carbohydrates in the rat. The animals were selected by age (10, 20, 30 and 40 days-old) and distributed in 3 experimental groups as follows: Group I -- Parotidectomized animals; Group II -- Sham-parotidectomized animals; and Group III -- Control animals. The animals from all the groups were sacrificed 20 days after the beginning of the experiment. From the discussion of the results it was observed that the parotidectomized animals at 20, 30 and 40 days have presented significantly larger glycaemic means than control animals. These control animals, by the other hand, have also presented significantly larger glycaemic means than sham-parotidectomized animals. Concerning the 10 days-old animals, the statistical analysis have not showed any significance among the three groups. The results obtained from hepatic glycogen dosages, in the same animals, have showed a coherence, because the animals that have presented larger glycaemic levels, have also presented less hepatic glycogen content; contrarily, the animals that have presented a less glycaemic levels, have also presented a larger amount of hepatic glycogen.

Age Factors↗
PubMed1977

Prevalence of dental caries in permanent teeth of white and black schoolchildren in Brazil.

The authors studied the prevalence of dental caries in white and black schoolchildren of Piracicaba, State of São Paulo, Brazil. The Student t-test, applied to the coefficient of prevalence of caries, revealed means significantly greater at the 5% level in whites than in blacks in the following groups: 7 years, both sexes; 8 years, both sexes; 9 years, males; 10 years, both sexes; 11 years, males.

Brazil↗