Heme modulates smooth muscle cell proliferation and migration via NADPH oxidase: a counter-regulatory role for heme oxygenase system.

Accumulation of vascular smooth muscle cells (VSMC) in response to inflammatory stimuli is a key event in atherogenesis, which commonly occurs in sinuous vessels with turbulent blood flow what leads to hemolysis and consequent free heme accumulation, a known pro-oxidant and pro-inflammatory molecule. In this work, we investigated the effects of free heme on VSMC, and the molecular mechanisms underlying this process. Free heme induces a concentration-dependent migration and proliferation of VSMC which depends on the production of reactive oxygen species (ROS) derived from NADPH oxidase (NADPHox) activity. Additionally, heme activates redox-sensitive proliferation-related signaling routes, such as mitogen activated protein kinase (MAPK) and NF-κB, and induces heme oxygenase-1 (HO-1) expression. NADPHox-dependent proliferative effect of heme seems to be endogenously modulated by HO since the pretreatment of VSMC with HO inhibitors potentiates heme-induced proliferation and, in parallel, increases ROS production. These effects were no longer observed in the presence of heme metabolites, carbon monoxide and biliverdin. The data indicate that VSMC proliferation induced by heme is endogenously modulated by a critical counter-regulatory crosstalk between NADPHox and HO systems.

Gas exchange, growth, and chemical parameters in a native Atlantic forest tree species in polluted areas of Cubatão, Brazil.

The Atlantic forest species near the industrial complex of Cubatão, Brazil have been subjected to heavy air pollution for decades. In this study, we used some physiological parameters (gas exchange, growth and chemical contents) to biomonitor the effects of air pollution on Tibouchina pulchra, one of the most common tree species in this forest. Under standardized conditions, saplings were exposed to the environment from April to July and from July to September of 1998, at three different sites in the vicinity of the industrial complex: the Valley of Pilões River (VP), the control area; the Valley of Mogi River (VM), near fertilizer, metallurgical, and cement industries sustaining high concentrations of fluorides, N and S oxides, and particulate materials; and Caminho do Mar (CM), near petrochemical industries under N and S oxides, photooxidants, and organic compounds. Plants exposed to CM and VM conditions presented visible injuries, reductions in net photosynthesis, growth parameters, and ascorbate concentrations, and increased F, N, and S foliar concentrations. These results indicate that the environmental conditions around these industries are still harmful to plants.

[Comparative study of breastfeeding period among children from internal and external day-care centers]. / Estudo comparativo do período de aleitamento materno de crianças em creches internas e externas.

A cross-sectional study was performed with 137 mothers and their children aged 0 - 35.9 months attending day-care centers (DCC) of Parobé and Três Coroas, Rio Grande do Sul, Brazil. The study analyzed the duration of breastfeeding among the children according to DCC in the same mothers' working place (internal DCC) or far from mothers' working place (external DCC). The prevalence of breastfeeding at 3, 6 and 12 months was 60%, 26% and 7%, respectively. There was a high statistically significant association between children in internal DCC and breastfeeding over 3 months of life (X(2)= 18.65; p = 0.00001). Mothers with children in internal DCC breastfed more during their working period then mothers with children in external DCC. The closeness of internal DCC to the working place may give the mothers a sense of serenity and safety. There is also more availability of the mothers to breastfeed during working time,this way maintaining the stimulation to breastmilk production and avoiding the introduction of bottle complements.