PubMed Health⌕ Search

Biomedical subjects

M L Bravo

Publications and source records attributed to M L Bravo.

23 records · Page 2Linked to original sources
PubMed1987

Immunogold staining of microtubules in resting and activated platelets.

A circumferential microtubule is known to support the discoid form of resting platelets, but its fate following exposure of the cells to aggregating agents is uncertain. The present study has employed an immunocytochemical approach to follow the fate of the circumferential microtubule in activated platelets. Monoclonal antibodies to tubulin and to vinculin and a polyclonal antibody to actin were incubated with isolated microtubule coils and stained with staphylococcal protein A coupled to immunogold in order to test their specificity. Thin sections of glycolmethacrylate embedded platelets before and after exposure to thrombin for 15, 30 and 60 s were stained with antibodies to tubulin and actin. Immunogold particles showed a high specificity for isolated MT coils stained for tubulin, modest intensity for actin, and none for vinculin. Gold particles were randomly distributed in thin sections of resting and activated platelets stained for actin. Immunogold was limited to the circumferential microtubule in resting platelets and constricted coils in thrombin-activated cells. The number of gold particles in areas of cytoplasm away from microtubules in platelets stained with antitubulin antibody increased slightly following thrombin activation, but the change was not significant. Results support the concept that microtubule coils supporting the discoid form of resting platelets do not dissolve following exposure of the cells to potent agonists.

Actins↗
PubMed1987

Interaction of long-term stored platelets with vascular subendothelium.

Platelets stored as platelet-rich plasma under mildly alkaline conditions in vitro maintain morphologic integrity and functional capability for 2 to 3 weeks. We used the Baumgartner method to assess the ability of long-term stored platelets to interact with exposed vascular subendothelium. After 3 days in storage the size and number of thrombi on damaged surfaces decreased. However, the percentage of vascular surface covered was not reduced significantly until the cells had been stored for 14 days. Treatment of vascular segments with chymotrypsin to increase thrombogenicity caused platelets stored for 14 days to adhere and form aggregates on denuded surfaces in a manner similar to that of fresh platelets, but the ability to develop thrombi remained depressed. Thus long-term storage that maintains physical and functional integrity also preserves a reasonable capacity of platelets to interact with damaged blood vessels.

Adult↗
PubMedDate not supplied

[Multiple sclerosis: epidemiological-genetic studies in the population of Antioquia, Colombia. Disequilibrium of HLA DQ alpha].

INTRODUCTION AND OBJECTIVE: Discrimination and quantification of the environmental and genetic components involved in developing multiple sclerosis (MS) have not been made. In order to discriminate these components we have ascertained affected individuals by MS belonging to the Paisa community from Antioquia, Colombia, a state localized in the tropical area of South America, to detect eventual linkage disequilibrium to HLA, locus DQ alpha, which could demonstrate the relevance of the genetic component. DEVELOPMENT: A contingence analysis among case-control HLA DQ alpha genotype distributions, by using Monte Carlo resampling method to solve small number sample, showed that there are significant differences between the two groups. We observe that HLA DQ alpha 1.1, 1.2 allele frequencies were higher in the cases than in the controls. Also, there was significant HLA DQ alpha 3 allele lower frequency (p < 0.05) in the cases than in the controls. CONCLUSIONS: Similar results have been described in other Caucasian populations living in non tropical areas. Before results could indicate that the Caucasoid populations genetic component implied in the susceptibility to MS have remained in Paisa community, whether the environmental component, being meaningful to develop MS.

Adult↗
PubMedDate not supplied

[The federal health expenditure on the uninsured population: Mexico 1980-1995].

In the last fifteen years Mexico suffered several economic crisis which have negatively affected public expenditure in social welfare and, as a consequence, public expenditure in health. This paper discusses the relationship between the adjustment policies adopted to confront these crisis and public expenditure in health care for the non-insured population, as well as the regional distribution of this expenditure. In part one, the evolution of general public expenditure, public expenditure in social welfare, and public expenditure in health between 1980 and 1995 is described. In part two, the distribution of public health expenditure for the non-insured population among the five regions in which the country was divided by the National Health Survey II is discussed. The main conclusion of this paper is that, between 1980 and 1995, the public expenditure gaps that have existed for a long time in Mexico among regions remained unchanged. These gaps basically affect the southern states of the country, are not related to health needs, and may deepen in view of the new relative cuts in public expenditure in social welfare announced by the new administration.

Financing, Government↗