The contribution of white and gray matter differences to developmental dyslexia: insights from DTI and VBM at 3.0 T.

Developmental dyslexia is one of the most common neuropsychological disorders in children and adults. Only few data are available on the pathomechanisms of this specific dysfunction, assuming--among others--that dyslexia might be a disconnection syndrome of anterior and posterior brain regions involved in phonological and orthographic aspects of the reading process, as well as in the integration of phonemes and graphemes. Therefore, diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) were used to verify the hypothesis of altered white and gray matter structure in German dyslexic adults. DTI revealed decreased fractional anisotropy (FA) in bilateral fronto-temporal and left temporo-parietal white matter regions (inferior and superior longitudinal fasciculus). Significant correlations between white matter anisotropy and speed of pseudoword reading were found. In dyslexics, gray matter volumes (as measured by VBM) were reduced in the superior temporal gyrus of both hemispheres. So far, our results, based on a combined analysis of white and gray matter abnormalities, provide exceedingly strong evidence for a disconnection syndrome or dysfunction of cortical areas relevant for reading and spelling. Thus, we suggest that this imbalance of neuronal communication between the respective brain areas might be the crucial point for the development of dyslexia.

Manual micromethods for bilirubin determination in sera of adults and children and investigation of reasons for observed differences.

This study compared three micromanual methods for determining bilirubin concentration. The two microchemical methods for total bilirubin, a Jendrassik-Grof procedure and a Unopette procedure, using dimethyl sulfoxide as an accelerator and protein solubilizer, gave comparable results in sera of adults and children. A microspectrophotometric method and the microchemical methods for total bilirubin gave similar results in plasmas of newborns with physiologic hyperbilirubinemia and in sera of older children with no hepatic abnormality. However, the microspectrophotometric method gave higher values in normal and hyperbilirubinemic adult sera. The results obtained with the Jendrassik-Grof and Unopette microchemical methods for direct bilirubin in sera of adults and children showed the values determined by the Unopette to be higher. Using the presently accepted normal range, this difference is significant enough to preclude recommendation of the use of the Unopette method for distinguishing normal from elevated levels of direct bilirubin. Direct bilirubin in newborn serum measured by the Unopette method is considerably higher than that measured by the Jendrassik-Grof method. An investigation to determine the reason for the difference in the direct bilirubin results indicated that the Unopette direct method measures diconjugated bilirubin in amounts similar to those measured by the Jendrassik-Grof method but significantly more monoconjugated bilirubin than the Jendrassik-Grof method.

Evaluation of the Honeywell ACS 1000.

The Honeywell ACS 1000, an automated computerized scanning system, is evaluated against the recommended manual method for WBC differentials. Over 400,000 data points were gathered by both methods during an 11-month study, employing routine peripheral blood smears and critically characterized control preparations. These data were found to exhibit an effective increase in throughput, precision, comparable accuracy, and a reduction in operator fatigue. In addition, the instrument demonstrates application to the improvement of quality control, teaching, and continuing education.