Frequency of viruses associated with acute respiratory infections in children younger than five years of age at a locality of Mexico City.

A locality in the district of Tlalpan, Mexico City, was selected in order to identify the viral agents in children younger than 5 years of age with acute respiratory infection (ARI). A total of 300 children were randomly selected and were included in this study for a period of 13 months. During this period nasopharyngeal exudates were collected for the isolation of viral agents. Monoclonal fluorescent antibodies were used for viral identification after cell culture. Viral infection was detected in 65% of the specimens. The respiratory syncytial virus (RSV) was the most common virus agent detected. Children required an average of two consultations during the study period. Two high incidence peaks were observed, one during the summer and the other during winter; the most frequent viruses during these seasons were influenza A and RSV, respectively. The largest number of viruses was isolated in the group of children between 1 and 2 years of age and in the group between 4 and 5 years of age. This study demonstrated the presence of ARI and of different viruses in a period of 13 months, as well as the most frequent viruses in children younger than 5 years of age from a community of Mexico City.

Parasitic mycelial forms of coccidioides species in Mexican patients.

Of 26 cases of coccidioidomycosis reported here, 15 showed hyphae, atypical parasitic structures of Coccidioides spp. in fresh cytologic and/or histologic specimen preparations. The finding of this morphology could have implications which should be considered, especially when the disease affects areas of nonendemicity.

An imported case of Blastomyces dermatitidis infection in Mexico.

Blastomycosis is an acute or chronic primary infection of the respiratory system, endemic in North America (United States of America and Canada), Africa and Asia. We report a case in Mexico, in a three years old child who had been born in California and lived in Chicago, U.S.A. The patient presented pulmonary symptoms prior to development of a skin ulcer. Blastomyces dermatitidis was identified by mycological and molecular procedures. The patient was successfully treated with amphotericin B, oral ketoconazole and itraconazole.

Comparative viral frequency in Mexican children under 5 years of age with and without upper respiratory symptoms.

In Mexico, there is a lack of up-to-date published data that show viruses to be the main cause of acute respiratory infection (ARI). The objective of this study was to estimate the comparative viral frequency between children under the age of 5 years with and without ARI (n = 179 in each group) in a suburban community (Nezahualcóyotl City). A nasopharyngeal sample was collected for viral culture and identification was carried out by indirect immunofluorescence (IIF) using mAbs. There were no sex differences between the two groups. Children under 1 year of age with ARI showed a higher frequency (56 %) of viral infections; this was statistically significant (P < 0.05) when compared with the same age group in ARI-free children (17 %). Respiratory syncytial virus (RSV) was the most prevalent type of virus isolated from both groups (38 vs 18 %). A statistically significantly higher number of subjects with ARI (33/179) than without (12/179) were infected with RSV (P < 0.003). Prevalences of four other viruses studied were similar in the two groups. The highest viral incidence of ARI in children was detected in the winter-spring seasonal period.

Effect of electrical stimulation of the baso-lateral amygdala nucleus on defensive burying shock probe test and elevated plus maze in rats.

In the present report, the putative effect of a single electrical stimulation (75, 150 or 300 microA) to the baso-lateral amygdala (BLA) nucleus was assessed in shock probe defensive burying behavior test (DB) and elevated plus maze (EPM). These models have been used for measuring anxiety levels and screening putative anxiolytic compounds. A group of 28 rats were randomly divided for the following experimental conditions: Control-control, sham-operated, BLA stimulated groups: 75, 150 and 300 microA tested for DB. The cumulative defensive burying in a 15 min-test, the latency of burying, the number of shock received and the height of the bedding material in the probe were recorded. Another group of 28 individuals was also randomly distributed for the following experimental conditions: Control-control, sham-operated, BLA stimulated animals: 75, 150, 300 microA and tested in the EPM. The time the subjects spent in the open arms, the crosses and the faeces number excreted during the test were recorded. Decreased levels of defensive burying were observed in 75, 150 and 300 microA stimulated groups. The 150 and 300 microA groups reached statistical significance. The fact that 300 microA stimulated group showed statistically significant increase in the latency of defensive burying, in the number of shock received and decreased amount in bedding material suggests a sedative action of electrical stimulation. Increased time in the open arms and augmented number of crossings in 150 microA group was observed. No changes in the number of faeces were observed in any group. The evidence supported the notion of an inhibitory amygdaline mechanism triggered by sub-threshold electrical stimulation.

Influence on collagen metabolism of vitreous from eyes with proliferative vitreoretinopathy.

PURPOSE: Proliferative vitreoretinopathy (PVR) is characterized by cell proliferation and membrane formation on the vitreoretinal cavity of the eye. The membranes are composed of extracellular matrix, mainly collagen type I. To explore the possible mechanisms involved in PVR membrane formation, the authors analyzed the role of vitreous humor on collagen turnover. METHODS: The authors studied vitreous samples from ten patients with PVR and from five donor eyes (keratoplasty) as the control group. Human lung fibroblasts were used to study the influence of vitreous on collagen synthesis and cell proliferation. Neutralizing antibodies against transforming growth factor-beta 2 (TGF-beta 2) were used to inhibit the fibroblast collagen synthesis induced by the vitreous samples. Collagenolytic activity was analyzed in vitreous fluid using 3H-labeled collagen. RESULTS: The authors found that samples obtained from patients with PVR significantly increased collagen synthesis (2979 +/- 963.26 versus 800 +/- 232 dpm of 3H-proline incorporated per milligram of vitreous-incubated protein; P < 0.00043), without affecting fibroblast replication. The collagen synthesis induced by the vitreous samples was inhibited by anti-TGF-beta 2 antibodies in both groups (0 and 481 +/- 59 dpm of 3H-proline incorporated per milligram of vitreous-incubated protein for control and PVR samples, respectively). Collagenolytic activity was considerably lower in vitreous derived from PVR samples compared with the control group (19.9 +/- 20.3 versus 234.1 +/- 19.1 micrograms of degraded collagen per milligram of vitreous-incubated protein; P < 0.0032). CONCLUSION: These results suggest that a combined mechanism, including an increase of collagen synthesis mediated at least in part by TGF-beta 2 and a decrease of collagen degradation, may contribute to the exaggerated deposition of collagen observed in PVR membranes, and that vitreous should be considered as a part of the microenvironment that is participating actively in the pathogenesis of this vitreoretinal disorder.