Treatment of lead poisoning with an immobilized chelator comparison with conventional therapy

Lead poisoning is a global public health problem. In pregnant women it may result in developmental delays of the fetus, in children it my produce learning disability. Available chelators are nephrotoxic when eliminated as lead-chelator complexes. For safe removal of lead from the body we developed a "Lead-Hemopurifier" (L-HP), a device with an immobilized chelator. In vitro, applied to lead solutions, this device reduced the lead concentration. Applied to dogs with lead intoxication, Lead-HP-s removed lead from the blood; this was continuously replaced by lead from the bones until the skeleton was cleared from lead deposit. Treatment of lead poisoning in dogs with Lead-HP-s compared favorably with Versenate treatment of children with lead toxicity. This report demonstrates the in vivo efficiency and safety of this new detoxfication method. Methods to induce lead poisoning in dogs and procedures to identify lead released from skeletal deposits are described.

Role of perceptual and conceptual similarity in category matching at age two years

Perceptual and categorical similarity were varied independently in a concept-matching task administered to 26-month-old children (N = 25). 44 test sets were assembled. Each set included a 3-dimensional standard and an array of 4 pictures, one of which was a member of the same basic or superordinate category as the standard. On each trial, placing the standard on the matching picture resulted in activation of 1 of 12 mechanical displays. The test sets varied in the perceptual and categorical resemblance of the standard to the match and to the nonmatches, as determined by adults' ratings. Perceptual similarity proved to be the primary determinant of difficulty level. When perceptual resemblance of the standard and the match were equated, superordinate and basic matches were equally difficult. When perceptual resemblance was minimal, most children were unable to recognize matches at either the basic or superordinate level.

Effect of moderately acidic pH on heat resistance of Clostridium sporogenes spores in phosphate buffer and in buffered pea puree

The effect of pH in the range 5.0 to 7.0 on the thermal destruction of spores of Clostridium sporogenes putrefactive anaerobe 3679 was examined by three methods: a capillary tube method in which spores were suspended in phosphate buffers, a thermoresistometer method in which spores were suspended in buffered pea puree adjusted to the same set of pH values, and a thermal death time can method in which spores were again suspended in buffered pea puree. The results indicated that increasing acidity is, in general, accompanied by decreasing heat resistance, although the pH effect was more pronounced at the higher than at the lower processing temperatures. Certain pH values appear to be critical, as they produced, in all three sets of experiments, effects which would not be predicted by the overall relationship between acidity and spore heat resistance. Differences between heat resistance in phosphate buffer as compared with that in pea puree adjusted to the same pH were also noted. D-values in buffer were found to be lower than those in pea puree, except at the highest temperatures coupled with the lowest pH values. The differences between buffer D-value and pea puree D-value were found to increase with increasing pH and with decreasing temperature. On the other hand, at all pH values examined, z-values determined in buffer were somewhat higher than those determined in pea puree adjusted to the same pH.