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Biomedical subjects

J M Alvarez

Publications and source records attributed to J M Alvarez.

At least 37 records · Page 2Linked to original sources

Airway disorders and pulmonary function in snorers. A population-based study.

The aim of our study was to determine the relationship between snoring, airway disorders and pulmonary function in the general population. We performed a stratified random sampling from the population (n = 92,364). Four hundred subjects agreed to participate and were invited to the clinic, where a detailed medical history, physical examination, spirometric test and maximal respiratory pressures measurements were carried out. Snoring was reported by 152 subjects (38%). Nasal obstruction and the presence of abnormal pharynx exploration were more frequent in subjects with snoring. Age, body mass index and neck circumference were significantly higher in the snorer group. In addition, we found that the non-snoring group had a significantly higher frequency of tonsillectomy during infancy and adolescence than the snorer group. We did not detect any significant difference in spirometric test values or in maximal respiratory pressure values between snorer group and non-snorer group. In conclusion, in the general population snoring is associated with nasal obstruction and abnormal pharynx exploration. Furthermore, snoring appears not to be associated with modifications in spirometric or in maximal respiratory pressure tests.

Adult↗

Mouse ear edema modulation by different propolis ethanol extracts.

The anti-inflammatory activity of 14 commercial ethanol extracts of propolis were evaluated, using a mouse ear inflammation model induced by arachidonic acid. Indometacin was also assayed as standard anti-inflammatory agent. Different activities were observed and discussed. This model could be used to assess the anti-inflammatory quality of propolis extracts and facilitate their posological usage on skin edema resulting from wounds.

Animals↗

Influence of acute-phase parasite load on pathology, parasitism, and activation of the immune system at the late chronic phase of Chagas' disease.

To obtain low and high parasite loads in the acute phase of Chagas' disease, A/J mice were infected with 10(3) or 10(5) Trypanosoma cruzi trypomastigotes of the Y strain and treated on day 6 with benznidazol. One year later, chronically infected mice were screened for subpatent parasitemias, tissue pathology, and immune response. Mice infected with the high parasite inoculum showed higher levels of chronic parasitemias, heart and striated muscle inflammation, and activation of the immune system than did mice infected with the low inoculum. Concerning the activation of the immune system, the main findings for high-dose-infected mice were (i) increased numbers of splenocytes, with preferential expansion of CD8(+) and B220(-) CD5(-) cells, many of them bearing a macrophage phenotype; (ii) higher frequencies of B (B220(+)), CD4(+), and CD8(+) large lymphocytes; (iii) a shift of CD4(+) cells towards a CD45RBLow phenotype; (iv) increased frequencies of both CD45RBLow and CD45RBHigh large CD4(+) cells; (v) augmented numbers of total immunoglobulin (Ig)-secreting cells, with predominance of IgG2a-producing cells; and (vi) increased production of gamma interferon and interleukin 4. In addition, these mice presented lower IgM and higher IgG2a and IgG1 parasite-specific serum antibody levels. Our results indicate that the parasite load at the acute phase of T. cruzi infection influences the activation of the immune system and development of Chagas' disease pathology at the late chronic phase of the disease.

Acute Disease↗

Prevalence of sleep disordered breathing and sleep apnea in 50- to 70-year-old individuals. A survey.

PURPOSE: To determine the prevalence of sleep disordered breathing (SDB) and sleep apnea syndrome (SAS) in a general population aged from 50 to 70 years. SUBJECTS AND METHODS: We recruited 76 individuals aged between 50 and 70 years, chosen at random from the electoral census. They were invited to the clinic where a detailed medical history was taken and physical examination, ENT examination, pulmonary function tests and night time recording of respiratory variables performed. RESULTS: The prevalence of SDB (apnea-hypopnea index >/= 5) was 28.9%, and there were no differences between men (28%) and women (30%). However, the prevalence of SAS was 6.8%, and there were differences between men (5 cases) and women (0 cases) (p = 0.0521). Subjects in the SDB group had higher systolic blood pressure than in the non-SDB group (p < 0.05). CONCLUSIONS: SDB and SAS are common among 50- to 70-year olds. The prevalence of SDB was 28.9% and the prevalence of SAS was 6.8%.

Aged↗

Role of membrane-bound IgM in Trypanosoma cruzi evasion from immune clearance.

We have recently described that Trypanosoma cruzi parasites of the reticulotropic Y strain increase their resistance to antibody-induced clearance during their interaction with the vertebrate host immune system. In the present study, we observed that trypomastigotes of the myotropic CL strain isolated from normal host also display an increased resistance to immune clearance when compared to parasites obtained from immunosuppressed donors. Through fluorescence-activated cell sorting analysis, we have observed that the high expression of membrane-bound IgM antibodies on Y and CL trypomastigotes correlates with their enhanced resistance to Ig-induced clearance. Trypomastigotes from normal mice were essentially refractory to the in vitro binding of immunoglobulins, showing that their membrane structures were completely covered by IgM antibodies. These findings suggest that this isotype does not efficiently mediate immune clearance. Moreover, membrane-bound IgM antibodies limited the amount of IgG attached to the parasite and, as a consequence, impaired efficient immune clearance. Through this mechanism, trypomastigotes of T. cruzi could increase their persistence in the bloodstream thus favoring parasite transmission to its hematophagous host vector in the early acute phase of the disease.

Animals↗