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Biomedical subjects

M A Barros

Publications and source records attributed to M A Barros.

24 records · Page 2Linked to original sources
PubMed1986

[Peutz-Jeghers syndrome. 2 cases].

We describe two cases of Peutz-Jeghers syndrome, a 13 years old female and a 8 years old male patients. In the first case the patient showed pigmented macules on lips, face and oral mucosa, as well as gastric and jejunal polyposis which caused total gastrectomy and segmental enterectomy. The second patient had melanosis on the lower lip, face, buccal mucosa, forearms and perianal area, and the gastric endoscopy revealed two small gastric polyps on the angular incisura.

Adolescent↗
PubMed1985

Genome evolution in pocket gophers (genus Thomomys). III. Fluorochrome-revealed heterochromatin heterogeneity.

Heterochromatin is a dominant component of the genome in the bottae group of the pocket gopher genus Thomomys, having had a major role in the karyotypic evolution of member species. Heterochromatin characteristics of two subspecies of T. bottae and one of T. umbrinus were examined with fluorochrome dyes identifying presumptive GC- and AT-rich regions. In two karyotype forms of T. b. fulvus and in T. umbrinus, chromatin that fluoresces brightly with chromomycin A3 is also C-band positive, although not all heterochromatin fluoresces. However, in T. b. bottae, only euchromatic regions fluoresce brightly with chromomycin. Fluorescence patterns produced with DAPI are the reverse of the chromomycin banding in all karyotypic forms. Heterochromatin in these taxa is thus highly differentiated, exhibiting heterogeneity in staining characteristics, and presumably in underlying DNA sequences, both across the genome within a given chromosomal complement as well as among the different karyotypic races and species of the bottae group of pocket gophers.

Animals↗
PubMed1979

Thrombin-like and factor X-activator components of Bothrops snake venoms.

A comparative study on the coagulant activity of snake venoms was carried out in 26 Bothrops species, using specific clotting systems for the thrombin-like and the factor X-activator activities. With only two exceptions (B. erythromelas and B. castelnaudi) all venoms showed thrombin-like activity, since they were able to clot fibrinogen directly. The absence of thrombin-like action of B. erythromelas venom is due to a fibrinogenolytic effect. Five venoms (B. atrox asper, B. bilineatus bilineatus, B. cotiara, B. fonsecai and B. itapetiningae) were unable to produce a prothrombin activator when preincubated with serum, factor V, and phospholipid. None of the venoms seems to require factors VII, VIII, IX, XII and XIII for their complete coagulant action. Direct prothrombin activation was observed in most of the Bothrops venoms, alone or combined with thrombin-like and factor X-activator activities. An anticoagulant activity was exhibited by B. castelnaudi venom, probably due to an anti-Xa action. This study points out that the coagulant activity of snake venoms varies within the same genus and must be characterized for each species. Thus, in Bothrops venoms the thrombin-like and factor X-activator components are not always associated, the coagulant effect may be related only to one of the components.

Animals↗
PubMedDate not supplied

[Usefulness of paraffin embedding as complementary technic in the diagnosis of thyroid aspirates].

PURPOSE: To compare the diagnostic value of conventional direct cytologic smears and paraffin embedding in the preparation of samples obtained by fine needle aspiration (FNA) biopsy. METHODS: Direct smears and paraffin embedding preparations were examined from 100 thyroid lesions. In 9 cases, the FNA smears and paraffin embedding blocks were, in addition, compared with surgical thyroid specimens. RESULTS: The FNA samples were adequate for diagnosis in the great majority of cases (93/100). In 72 aspirates, both smears and paraffin embedding preparations were adequate. In 17 cases only he latter preparations and in 4 specimens only the smears were considered adequate. When both smears and paraffin blocks were available (72 aspirates), there was diagnostic agreement in 63 cases. Overall the diagnostic percentage of FNA/paraffin-block preparations was 95.7% and of FNA/conventional smears was 81.7%. Statistical analysis demonstrated that paraffin blocks increased the diagnostic accuracy of thyroid FNA (p < 0.01). CONCLUSION: Our data point out to the value of complementing conventional FNA smears with paraffin embedding preparations for the diagnosis of thyroid lesions.

Adolescent↗