An evaluation of the effects of breakfast on classroom behaviours in Jamaican schoolchildren - abstract

Children's behaviours may be affected by short-term food deprivation, and this may hinder their ability to learn in class. However, there are few adequate evaluations of the effect of nutrition on classroom behaviour in Jamaica. We evaluated the effects of giving breakfast on the classroom behaviours of 50 undernourished and 60 adequately nourished children aged 8-11 years, selected from 4 poor rural schools. The children were observed twice, once after receiving breakfast and once after a placebo. The behaviours were observed in teaching and set task situations and included attention to task, talking to another child, gross motor behaviour and responding to teacher. A time sampling method was used. This technique estimates the number of times actual behaviours occur. The test retest reliabilities ranged from 0.6 to 0.9 (Spearman-Brown coefficient). The undernourished children moved around the classroom more than the adequately nourished children. The impact of breakfast varied among the schools but not between nutritional groups. In the school which was better equipped and organized, the children were more attentive (p<0.01) and moved less (p<0.05) when they received breakfast. In the poorer schools there was no improvement and, in one, the children's attention to task was less when given breakfast (p<0.02). School breakfasts may therefore only benefit children's behaviours in the presence of satisfactory classroom infrastructure (AU)

Enhanced resistance to Nocardia brasiliensis infection in mice depleted of antigen-specific B cells.

This study deals with the roles of T and B cells in Nocardia brasiliensis infection in mice. Nocardia injected into the animals' footpads caused inflammatory responses and mycetomas in situ, resulting in granulomatous lesions of subcutaneous tissues and eventual bone destruction. These clinical features resemble those of humans infected with Nocardia. The effect, if any, of antibody was studied by passively transferring anti-Nocardia serum into either immunologically normal or T-deficient infected mice. Such transfers had no protective function in either group. To the contrary, the antibody seemed to favor infection and worsen bone disease compared to that in mice not given antibody. Furthermore, passive transfer of the antibody along with injection of Nocardia coated with the antibody magnified the severity of subsequent symptoms. Although these experiments ruled out any role for antibody in protection from Nocardia, they did not directly prove T cell participation in such resistance. Therefore, the role of T cells during Nocardia infection was examined further by transferring spleen cells depleted of B lymphocytes bearing receptors for a Nocardia extract (NE). Lethally irradiated mice reconstituted with a population depleted of NE-specific B cells totally lacked the ability to form antibodies to NE; however, they mounted effective delayed-type hypersensitivity reactions and completely controlled their Nocardia infection, establishing the importance of cell-mediated immunity in halting this disease process.