Fast evaluation of intraoperative biopsies for ganglia in Hirschsprung's disease

PURPOSE

The most important diagnostic features of Hirschsprung's disease (HD) are the combination of aganglionosis and hypertrophic nerve bundles. Acetylcholinesterase staining is widely used for diagnosis of HD as it identifies hypertrophic nerves in both diagnostic and intraoperative biopsies. The main drawback of this method is in the identification of ganglia. It has been suggested that the combination of this method together with another histochemical marker would be a superior diagnostic tool. Hematoxylin and eosin is still the diagnostic measure of choice for identifying ganglia in many centers, although it presents a persistent diagnostic challenge for pathologists trying to rapidly and accurately interpret the frozen biopsies that guide intraoperative decision making.

METHODS

Therefore, we sought to develop a fast, intraoperative immunohistochemical protocol for visualization of ganglia and nerves in HD specimens that can be used in conjunction with these other tools.

RESULTS

With the use of acetone fixation and immunofluorescence staining with antibodies to neurofilament 68 and tubulin, ganglia in sections of full thickness and suction biopsies could be visualized in only 10 minutes. This protocol facilitated the identification of ganglia in hematoxylin and eosin-stained adjacent sections and also identified hypertrophic nerve trunks.

CONCLUSION

This method should significantly enable the identification of ganglia in suction and full thickness biopsies.

Hippocampal volume and glucose metabolism in temporal lobe epileptic foci

PURPOSE

Reports conflict on the relation of glucose metabolism to hippocampal volume in temporal lobe foci. Previous studies usually have used side-side ratios rather than regional metabolic rates.

METHODS

We measured hippocampal volume and glucose metabolism in 37 patients with temporal epileptogenic zones identified by ictal video-EEG telemetry. Metabolic rates were normalized to global brain mean.

RESULTS

Both 18-fluoro-2-deoxyglucose-PET and volumetric MRI lateralized the epileptic focus determined by ictal video-EEG. There were significant correlations between left-right metabolic asymmetry and hippocampal formation volume left-right ratios. Comparisons between normalized metabolism and hippocampal formation volume, ignoring the side of the epileptic focus, showed significant relations between left hippocampal volume and left inferior lateral temporal metabolism, right hippocampus and right inferior mesial temporal, and left hippocampus and left inferior mesial temporal metabolism. In contrast, when normalized metabolism was compared with hippocampal volume in the epileptic focus, no relation was found.

CONCLUSIONS

Our study suggests that the relation between hippocampal volume and glucose metabolism breaks down in epileptic foci and that hypometabolism is not dependent on neuronal loss. It is consistent with data suggesting that hypometabolism is an independent predictor of surgical outcome.

Phenotypic variability of Gerstmann-Sträussler-Scheinker disease is associated with prion protein heterogeneity

Gerstmann-Sträussler-Scheinker disease (GSS), a cerebello-pyramidal syndrome associated with dementia and caused by mutations in the prion protein gene (PRNP), is phenotypically heterogeneous. The molecular mechanisms responsible for such heterogeneity are unknown. Since we hypothesize that prion protein (PrP) heterogeneity may be associated with clinico-pathologic heterogeneity, the aim of this study was to analyze PrP in several GSS variants. Among the pathologic phenotypes of GSS, we recognize those without and with marked spongiform degeneration. In the latter (i.e. a subset of GSS P102L patients) we observed 3 major proteinase-K resistant PrP (PrPres) isoforms of ca. 21-30 kDa, similar to those seen in Creutzfeldt-Jakob disease. In contrast, the 21-30 kDa isoforms were not prominent in GSS variants without spongiform changes, including GSS A117V, GSS D202N, GSS Q212P, GSS Q217R, and 2 cases of GSS P102L. This suggests that spongiform changes in GSS are related to the presence of high levels of these distinct 21-30 kDa isoforms. Variable amounts of smaller, distinct PrPres isoforms of ca. 7-15 kDa were seen in all GSS variants. This suggests that GSS is characterized by the presence PrP isoforms that can be partially cleaved to low molecular weight PrPres peptides.

Face and word memory differences are related to patterns of right and left lateral ventricle size in healthy aging

Discrepancy between face word memory was measured with experimental continuous recognition tests and compared with right-left asymmetry of lateral ventricle size, measured with volumetric x-ray computed tomography, in 10 young and in 10 elderly subjects. All were right-handed and healthy. Old subjects differed significantly from young subjects on face but not word memory. Old subjects had significantly larger lateral ventricles than did young subjects and more lateral ventricle asymmetry. No group trend toward disproportionate age-related enlargement of the right ventricle relative to the left was noted. In old subjects, however, lateral ventricle asymmetry correlated with face-word memory discrepancies in the expected direction, worse word than face memory being associated with disproportionate enlargement of the left lateral ventricle. These correlations were not significant in young subjects. These results suggest that the group trend toward disproportionate nonverbal/visual, as opposed to verbal, age-related memory differences is not associated with a group trend toward disproportionate enlargement of the right ventricle. Individual deviations from the normative pattern of age-related ventricle enlargement, however, are associated with different patterns of material-specific memory changes.