Qualitative and quantitative changes in normal aging and alzheimer''s disease

Qualitative changes in normal aging and Alzheimer's disease (AD) are as important as quantitative changes. Although qualitative changes do not co-vary with quantitative differences in every respect, quantitative changes, nevertheless, often accurately reflect qualitative changes. Moreover, the complementary use of each provides a more detailed characterization of brain changes with aging and AD. The quantitative and qualitative changes of choline acetyltransferase, as well as somatostatin-containing neurons and dendrites, in human cortex are described as examples of this.     

Over‐expression of BACH2 is related to ongoing somatic hypermutation of the immunoglobulin heavy chain gene variable region of de novo diffuse large B‐cell lymphoma

The basic region–leucine zipper (bZip) factor BTB, CNC homology 2 (BACH2) is known to have important roles in class switch recombination and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. In this study, we investigated the relationship between the expression of BACH2 and the status of SHM of the Ig heavy chain gene variable region (IgHV) for SHM in diffuse large B‐cell lymphoma (DLBCL). We examined 20 cases of DLBCL, 13 of which were germinal center B‐cell (GCB) DLBCL and 7 were non‐GCB DLBCL. Seven cases were negative, 6 were positive (cytoplasmic expression) and 7 were strongly positive (both nuclear and cytoplasmic expression) for BACH2. Confirmed mutation (CM) was identified in 8 cases and the CM index (number of confirmed mutations per 10 subclones) was distributed from 0 to 5. A CM index of 7 strongly positive (over‐expression) cases with BACH2 were distributed from 0 to 5, and that of 7 negative and 6 positive cases were distributed from 0 to 1. Over‐expression of BACH2 was statistically related to CM index (P = 0.008). In conclusion, over‐expression of BACH2 is critical for ongoing SHM of IgHV in DLBCL, and our data suggest that BACH2 may play an essential role for SHM of the Ig gene in B‐cell lymphoma.     

Degradation of human secretory immunoglobulin A by protease isolated from the anaerobic periodontopathogenic bacterium, Bacteroides gingivalis

This bacterium is implicated in periodontal diseases of human adult type. Secretory immunoglobulin A (IgA) purified from human colostrum (HC-IgA) was incubated with Bacteroides gingivalis cells or protease isolated from the culture supernatant of B. gingivalis; the digestion of IgA was determined by immunoelectrophoresis and sodium dodecyl sulphate-polyacrylamide gel electrophoresis. B. gingivalis cells almost completely degraded HC-IgA; protease isolated from the culture supernatant cleaved both HC-IgA and secretory IgA in human parotid saliva. Thus by degradation of IgA, the protease may mediate in part the periodontopathogenic role of B. gingivalis by decreasing the oral defence mechanism.     

Black-pigmented, asaccharolytic Bacteroides species resembling Porphyromonas gingivalis (Bacteroides gingivalis) from beagle dogs

Black-pigmented, asaccharolytic Bacteroides strains, which positively reacted with anti-Bacteroides gingivalis (now reclassified as Porphyromonas gingivalis) serum, were isolated from beagle dogs, and their characteristics were studied and compared with those of P. gingivalis. The strains from dogs were different from P. gingivalis in their catalase activity, nutritional requirements and oxygen tolerance, and double-immunodiffusion tests showed serological dissimilarity between the strains from dogs and P. gingivalis. However, the strains from dogs had guanine-plus-cytosine contents of 49.0 to 49.3 mol %, which were very similar to P. gingivalis, and they showed strong DNA-DNA hybridization with P. gingivalis. These results indicated that beagle dogs had Porphyromonas species analogous to P. gingivalis in their oral cavities.     

Human slow cortical potential in association with voluntary jaw movements

The distribution of a readiness potential (RP), i.e., a negative-going slow cortical potential (SCP) preceding the onset of voluntary movements, was studied in association with self-paced voluntary jaw-closing and jaw-opening movements in 4 healthy human subjects. A negative-going SCP starting at ca.1.5-2.0 s preceding the onset of the self-paced jaw-opening and jaw-closing movements was found at all the recorded sites of Fz, Cz, Pz, F3, F4, F7, F8, C3, C4, T3 and T4. The RP was maximum in amplitude at Cz (ca.8microV), although there was no significant difference between Cz and either C3 or C4; it was smaller at T3 and T4 than at any of Fz, Cz, Pz, C3, and C4. The polarity, amplitude, and time course of the RP in association with jaw movements was virtually the same as those associated with voluntary unilateral extension of the middle finger, except for a contralaterally-dominant side asymmetry between C3 and C4 in the latter. There was neither rapidly increasing negative potential (NS') in the RP recorded from any site, nor bilateral difference in the RPs coinciding with unilateral biting of a gauze pad. It is suggested that the motor cortex would be activated bilaterally in coordination even in the case of unilateral biting.