Abstract Objective Construct validity for the Motor Development Scale (MDS) has not been established. The aim of this study was to examine whether the unidimensional model of MDS would be appropriate for children aged 4 to 6 years-old and provide construct validity for the items concerning this age group in Brazil. Methods A total of 938 children participated in the study (214 4-year-olds, 643 5-year-olds, and 81 6-year-olds). Confirmatory factor analysis (CFA) was used to evaluate construct validity of the MDS using a unidimensional model. Results The CFA for the unidimensional model showed excellent adequacy indices for age 4: χ2(2) = 0.581, p = 0.748, comparative fit index (CFI) = 1.000, Tucker-Lewis index (TLI) = 1.090, root mean square error of approximation (RMSEA) = 0.000 (90% confidence interval [90%CI] = 0.000 to 0.093, close fit [Cfit] = 0.841); age 5: χ2(2) = 2.669, p = 0.263, CFI = 0.993, TLI = 0.980, RMSEA = 0.023 (90%CI = 0.000 to 0.085, Cfit = 0.682), weighted root mean square residual (WRMR) = 0.407; and age 6: χ2(9) = 8.275, p = 0.506, CFI = 1.000, TLI = 1.010, RMSEA = 0.000 (90%CI = 0.000 to 0.118, Cfit = 0.653), WRMR = 0.495. Reliability was good: ω = 0.87 (95%CI = 0.81 to 0.92). Conclusion The proposed unidimensional solution for the MDS provides a concise, parsimonious and reliable way to assess motor development in children aged 4 to 6 years.

Snake venoms are toxic to a variety of cell types. However, the intracellular damages and the cell death fate induced by venom are unclear. In the present work, the action of the South American rattlesnake Crotalus durissus terrificus venom on CHO-K1 cell line was analyzed. The cells CHO-K1 were incubated with C. d. terrificus venom (10, 50 and 100g/ml) for 1 and 24 hours, and structural alterations of actin filaments, endoplasmic reticulum and nucleus were assessed using specific fluorescent probes and agarose gel electrophoresis for DNA fragmentation. Significant structural changes were observed in all analyzed structures. DNA fragmentation was detected suggesting that, at the concentrations used, the venom induced apoptosis.

The pharmacological effects of Bothrops neuwiedi pauloensis venom on mouse phrenic nerve-diaphragm (PND) preparations were studied. Venom (20 mug/ml) irreversibly inhibited indirectly evoked twitches in PND preparations (60 ± 10% inhibition, mean ± SEM; p<0.05; n=6). At 50 mug/ml, the venom blocked indirectly and directly (curarized preparations) evoked twitches in mouse hemidiaphragms. In the absence of Ca2+, venom (50 mug/ml), produced partial blockade only after an 80 min incubation, which reached 40.3 ± 7.8% (p<0.05; n=3) after 120 min. Venom (20 mug/ml) increased (25 ± 2%, p< 0.05) the frequency of giant miniature end-plate potentials in 9 of 10 end-plates after 30 min and the number of miniature end-plate potentials which was maximum (562 ± 3%, p<0.05) after 120 min. During the same period, the resting membrane potential decreased from - 81 ± 1.4 mV to - 41.3 ± 3.6 mV 24 fibers; p<0.01; n=4) in the end-plate region and from - 77.4 ± 1.4 to -44.6 ± 3.9 mV (24 fibers; p<0.01; n=4) in regions distant from the end-plate. These results indicate that B. n. pauloensis venom acts primarily at presynaptic sites. They also suggest that enzymatic activity may be involved in this pharmacological action.