Transient P300 abnormality of event-related potentials following unilateral temporal lobectomy

Abstract Event-related potentials (ERP) were recorded during auditory oddball tasks for a patient prior to and soon after left anterior temporal lobectomy. The N100 amplitude decreased bilaterally although the latency did not change after the lobectomy. The P300 amplitude decreased in the left hemisphere at 1 and 2 weeks after surgery, then recovered to the pre-operative level at 4 weeks. These findings suggest that the medial temporal structure participates in the generating system of P300.     

Interferon-related mental deterioration after craniotomy for removal of metastatic renal cancer

Interferon-related severe adverse events on the central nervous system are relatively rare, because interferon-alpha (INF-alpha) can not cross an intact blood-brain barrier. We experienced remarkable mental deterioration caused by INF-alpha administration in a 43-year-old man with renal cell carcinoma after surgical removal of a metastatic brain tumor. We detected a high concentration of INF-alpha in a cerebrospinal fluid sample, which was comparable to that in the serum at 24 h after the administration of INF-alpha; 5x10(6) IU i.m., suggesting that the blood-brain barrier was damaged somehow by the craniotomy. The mental deterioration improved shortly after discontinuation of the INF-alpha administration.     

Correlation of enhanced cell proliferation with decreased density of vitamin D receptor in parathyroid hyperplasia in chronic dialysis patients

Summary: The decreased density of the vitamin D receptor (VDR) plays an important role in the pathogenesis and progression of parathyroid hyperplasia in renal failure. In chronic dialysis patients, VDR density is less in nodular hyperplasia than in diffuse hyperplasia and the difference of cell proliferation has been also suggested by DNA analysis. to prove a more direct correlation between VDR density and cell proliferation, VDR density and proliferating cell nuclear antigen (PCNA) were detected in situ by immunohistochemistry in serial sections of surgically excised parathyroid glands from 10 chronic dialysis patients. Among 28 excised glands, 20 glands were nodular hyperplasia and eight glands were diffuse hyperplasia. Vitamin D receptor positive cells were much fewer in nodular hyperplasia (13.1 ± 4.8%) than in diffuse hyperplasia (383 ± 5.6%). In contrast, mean PCNA positive cell numbers per one 400 x field were much higher in nodular hyperplasia (2.0± 1.2) than in diffuse hyperplasia (0.1±0.2). These two parameters, simultaneously detected in the same area of the serial sections, showed strong negative correlation (r= -0.719, P <0.0001). Remarkable differences in VDR and PCNA were evident between nodules and the surrounding diffuse hyperplasia in the same section. These data suggest more direct relationship between the decrease of VDR density and parathyroid cell proliferation in chronic renal failure as a pathophysiological mechanism.     

Delineation of producing ability of IgG and IgA subclasses by naive B cells in newborn infants and adult individuals

Neonatal B cells with the naive (sIgD⁺) phenotype are able to generate IgG- and IgA-producing cells as well as IgM production in the presence of memory CD4⁺ T cells expressing L-selectin (CD62L) in pokeweed mitogen-stimulated cultures. We used this system to examine comparatively the ability of naive B cells to produce IgG and IgA subclasses in newborn infants and adult individuals. Naive B cells were enriched from both donors on the basis of sIgD positivity, and memory (CD45RO⁺) CD4⁺ T cells with CD62L expression were isolated from adults. We here demonstrate some differences in profiles of IgG and IgA subclass production between neonatal and adult naive B cells. In neonatal B cells, IgG1 and IgG3 were predominantly produced, but IgG2 and IgG4 production was virtually absent. Similar to neonatal B cells, adult naive B cells produced mainly IgGq and IgG3, although memory (sIgD’) B cells from adults secreted all of the IgG subclasses. It should be noted that low but detectable levels of IgG2 and IgG4 were found in adults’naive B cell cultures. Although IgA produced by neonatal B cells was exclusively IgA1, IgA2-secreting cells were identifiable in adult naive B cells. The results suggest that further class switch of naive B cells to IgG2, IgG4 and IgA2 in addition to IgG1 and IgG3 may be controlled by their own age-dependent maturation process.     

Werner's syndrome – chromosome analyses of cultured fibroblasts and mitogen-stimulated lymphocytes

Two cases of Werner's syndrome are reported. Fibroblasts derived from both patients revealedreduced population doubling numbers. Chromosomal analyses for fibroblasts from both patients and lymphocytes from one patient revealed that chromosomal aberrations occur frequently and randomly. Although some of the chromosomal aberrations involved sites where tumour suppressor genes have been mapped, neither of our patients demonstrated malignancy. Chromosomal aberration at one critical site may not be sufficient to induce cancer or additional factors may be necessary.