Zinc tolerance modulation in Myracrodruon urundeuva plants.

We investigated Zn tolerance and related tolerance mechanisms of Myracrodruon urundeuva by evaluating the growth (biomass production, pigment content, and photosynthetic activity) and antioxidant systems (redox potential and antioxidant enzyme activities) of seedlings exposed to increasing Zn doses. Plants were grown for 120 days in substrates with 0, 50, 80, 120 and 200 mg Zn kg(-1) and demonstrated Zn-tolerance. Zn doses greater than 80 mg Zn kg(-1) were phytotoxic but not lethal, and Zn toxicity under these conditions was imposed by oxidative stress caused by hydrogen peroxide (H2O2) accumulation and related lipid peroxidation. Zn tolerance in M. urundeuva is linked to the activity of antioxidant systems in their leaves that are modulated by that metal: both superoxide dismutase (SOD) and catalase (CAT) were always higher in the presence of Zn; lower Zn doses stimulated ascorbate peroxidase (APX) and glutathione reductase (GR) activities, but enzyme activity was inhibited at high doses; APX appeared to be the main peroxidase in H2O2 scavenging as stimulated guaiacol peroxidase (GPX) activity was not sufficient to avoid H2O2 accumulation at higher Zn doses; the modulation of APX and GR activities was linked to changes in the redox status of leaves.

[Clinical profile in children under five year old with acute respiratory tract infections] / Perfil clínico de crianças menores de cinco anos com infecção respiratória aguda.

OBJECTIVE: To describe the clinical and epidemiological profile of acute respiratory infections (ARI) in children younger than five years old, of both sexes, diagnosed at the University Hospital Júlio Müller.METHODS: This is a descriptive and cross sectional study. A standard questionnaire was answered by the childrens parents, during the period of October/1996 to February/1997. The cases were classified according to the Health Ministry criteria in Upper Airway Infection (UAI) or Acute Lower Respiratory Infection (ALRI). The following data were analyzed: signs and symptoms, clinical diagnosis, socioeconomic variables, nutritional appraisal and passive smoking. The data were analyzed with EPI-Info 6.02b program. The X(2) test was used with confidence interval of 95% (a = 5%).RESULTS: The ARI prevalence in children under five years was 25.6%. From the total number of 491 children, 76.4% (n=375) had UAI and 23.6% (n=116) ALRI. The most frequent diagnosis was nasopharyngitis. The most frequent respiratory symptoms were nasal discharge (82.1%) and cough (80.4%). Around 6.1% of the total number of the cases were due to pneumonia (77.7% of the cases involving hospitalization). There were no associations of ARI with children s nutritional status, family income or passive smoking. There was statistical association between maternal educational status and ALRI (X(2)= 16.57).CONCLUSIONS: The findings show that most of the children presented nasopharyngitis (UAI), being most of them male. Pneumonia (ALRI) was the main cause of hospitalization. The most common symptoms were nasal discharge and cough. Besides, the most important risk factor associated was the mothers educational status.