PubMed Health⌕ Search

Biomedical subjects

M Corrêa

Publications and source records attributed to M Corrêa.

5 recordsLinked to original sources
PubMed2006

Acetylcholinesterase activity in rats experimentally demyelinated with ethidium bromide and treated with interferon beta.

The ethidium bromide (EB) demyelinating model was associated with interferon beta (IFN-beta) to evaluate acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC), cerebellum (CB), hypothalamus (HY), pons (PN) and synaptosomes from the CC. Rats were divided into four groups: I control (saline), II (IFN-beta), III (EB) and IV (EB and IFN-beta). After 7, 15 and 30 days rats (n = 6) were sacrificed, and the brain structures were removed for enzymatic assay. AChE activity was found to vary in all the brain structures in accordance with the day studied (7-15-30 days) (P < 0.05). In the group III, there was an inhibition of the AChE activity in the ST, CB, HY, HP and also in synaptosomes of the CC (P < 0.05). It was observed that IFN-beta per se was capable to significantly inhibit (P < 0.05) AChE activity in the ST, HP, HY and synaptosomes of the CC. Our results suggest that one of the mechanisms of action of IFN-beta is through the inhibition of AChE activity, and EB could be considered an inhibitor of AChE activity by interfering with cholinergic neurotransmission in the different brain regions.

Acetylcholinesterase↗
PubMed2001

Immunostimulatory DNA from Paracoccidioides brasiliensis acts as T-helper 1 promoter in susceptible mice.

Th1 immune responses afford protection against some pathogens like the fungus P. brasiliensis (P.b.), etiological agent of Paracoccidioidomycosis (PCM). It is well known that nonmethylated CpG sequences from bacterial DNA have immunomodulatory properties and can be used as a Th1-promoting adjuvant. By analyzing the available gene sequences of P.b. we observed a high number of unmethylated CpG dinucleotides. In a murine model of the PCM infection, the isogenic mouse strain known to be susceptible presents a predominant Th2 pattern. In order to access the possibility of the genomic DNA to act as a Th1-promoting adjuvant, in vitro assays were made and indicated a significant increase in phagocytosis when the macrophages were stimulated with DNA from P.b. and in vivo assays of a decreased production of antibodies antigp43, the main antigen of the PCM system. The analysis of the antibody isotypes and the cytokine production suggested a Th1 modulation in the susceptible animals. Thus, when mice were infected with fungus plus synthetic oligodeoxynucleotide (ODN), made from the available sequence of gp43, a decrease in the fungus dissemination was observed. Results herein described suggest that genomic DNA from P.b. could have a immunostimulatory function as a Th-1-promoting adjuvant in susceptible mice.

Adjuvants, Immunologic↗
PubMed1980

Suppressive activity of splenic adherent cells from Plasmodium chabaudi-infected mice.

The immune response of splenic cells to SRBC and LPS or Con A mitogens is suppressed in P. chabaudi-infected mice. When mixed with cells from normal donors, spleen cells from infected mice also suppressed anti-SRBC and mitogenic responses. Suppression was not detected in lymph node cells, bone marrow, or thymocytes from infected mice. Removal of infected red cells had no effect on suppression. The cell population responsible for the suppressive activity was adherent to plastic, resistant to irradiation and anti-Thy-1 plus complement treatment.

Animals↗
PubMedDate not supplied

[The Helsinki Declaration: relativism and vulnerability].

The Helsinki Declaration is a crucial ethical landmark for clinical research involving human beings. Since the Declaration was issued, a series of revisions and modifications have been introduced into the original text, but they have not altered its humanist approach or its international force for regulating clinical research. A proposal for an extensive revision of the Declaration's underlying ethical principles has been debated for the past four years. If the proposal is approved, international clinical research involving human beings will be modified, further increasing the vulnerability of certain social groups. This article discusses the historical process involved in passing the Helsinki Declaration and the most recent debate on the new draft. The article analyzes the new text's social implications for underdeveloped countries, arguing for a political approach to the vulnerability concept.

Bioethics↗