PubMed · 4820708
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R Adler, J H Goldstein. 1974. Strabismus screening in pediatrics.. https://doi.org/10.1016/s0022-3476(74)80020-x
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Authors report about a seemingly increase of the number of pediatric brain tumors in Borsod county region North-East Hungary. In a retrospective study they conclude, that this phenomenon may to a great extent be artificial, that is, it may reflect the improvement of diagnostic possibilities, above all the new imaging modalities. At their Institution the pattern of brain tumors is similar to that reported in the literature. In addition a racial difference has been detected, since the gipsy population of this region seems to have lower incidence of pediatric brain tumor than the Hungarian majority.
Lowering extracellular calcium concentration [Ca2+]o in rat hippocampal slices can lead to an induction of epileptiform activity. It has been shown that this effect is more pronounced in slices of neonatal rats (postnatal day, PND 8-19) than in mature slices (> PND 40) and it has been suggested that unique N-methyl-D-aspartic acid (NMDA) receptor properties of immature rat hippocampal pyramidal cells contribute to this developmental effect. In a voltage clamp experiment we tested NMDA receptor properties in hippocampal pyramidal cells by measuring NMDA receptor mediated currents evoked by iontophoretic applied NMDA in the basal dendrites of CA3 pyramidal neurons. We found that lowering extracellular calcium from 2 to 1 mM, increases NMDA evoked inward current in pyramidal cells around the resting membrane potential. However, this effect is observed in slices of neonatal as well as in slices of mature rats, suggesting that there is no difference in NMDA receptor sensitivity to extracellular Ca2+ between these two age groups. The modulation of the NMDA receptor by extracellular calcium at physiological concentrations can have important consequences in pathological conditions during which extracellular calcium reaches low levels. Because this 'hypocalcemic' condition induces a larger current influx via the NMDA receptor channel at resting membrane potentials, it can further enhance cellular excitability and contribute to sustain epileptiform activity.