Characterization and differential distribution of the three major human protein kinase C isozymes (PKC alpha, PKC beta, and PKC gamma) of the central nervous system in normal and Alzheimer's disease brains

Brain kinases may play important roles in normal memory as well as in the pathogenesis of neurodegenerative diseases. However, there is scant information on these enzymes in the human brain. For this reason, we characterized the immunohistochemical localization of protein kinase C (PKC) isozymes in human Alzheimer's disease (AD) and non-AD control brains. Using monoclonal antibodies to PKC alpha, PKC beta, and PKC gamma isozymes, we (a) determined the distribution of each PKC isozyme in eight different brain regions (cerebellum, hippocampus, as well as midfrontal, orbital frontal, motor, occipital, parietal, and temporal cortices) from AD and non-AD control brains and found that these patterns were generally similar to those in the rat brain; (b) showed that there were no significant differences in the normal staining intensity of the monoclonal antibodies in AD and non-AD control brain regions except in the hippocampus; (c) observed striking PKC immunoreactivity in globular and linear profiles in the periphery (corona) of AD senile plaques; and (d) demonstrated that PKC alpha immunoreactivity was enhanced in reactive astrocytes associated with senile plaques and other lesions (embolic infarcts) in both AD and non-AD control brains. The data on the normal distribution of each PKC isozyme were corroborated in quantitative studies of PKC alpha, PKC beta, and PKC gamma protein levels in human postmortem brain regions by Western blotting using our antibodies. We conclude that these three major PKC isozymes can be analyzed directly in postmortem human brain, which is an important first step in understanding the potential role that abnormal phosphorylation might play in the pathogenesis of AD.     

The skin,tongue, and brain as favorable organs for hog cholera diagnosis by immunofluorescence

Summary Hog cholera virus antigens were found densely distributed in skin and tongue of pigs experimentally infected with hog cholera virus. The finding described here warrants the usage of ear biopsies for hog cholera diagnosis on a herd basis.     

Adenosine receptor density and the depression of evoked neuronal activity in the rat hippocampus in vitro

The relationship between the heterogeneous distribution of A-1 adenosine receptors and the capacity of adenosine to depress neuronal activity was examined in the rat hippocampus. Utilizing autoradiographic techniques, the distribution of A-1 adenosine receptors was assessed by the binding of [3H]cyclohexyladenosine ([3H]CHA) to cryostat sections of rat brain. The apical dendritic region of CA1 showed a differential distribution of adenosine receptors between the stratum radiatum and stratum lacunosum/moleculare. The physiological relevance of this binding difference was studied in the hippocampal slice by examining the capacity of adenosine to depress evoked potentials in these two strata. It was observed that the receptor differences correlated with differential sensitivities to adenosine modulation of the evoked potentials. These data suggest that receptor density, as shown by binding techniques, may provide not only a qualitative but also a quantitative map of the sites of adenosine action.     

Structural studies on H-2Db and H-2Kd molecules indicate that murine major histocompatibility b and d haplotype alloantigens share structural features

Structural properties of the H-2D^b and H-2K^d murine major histocompatibility complex (MHC) antigens were examined by radiochemical methods. Radiolabelled preparations of the H-2D^b and H-2K^d antigens were obtained by indirect immune precipitation of NP-40 lysates of the lymphoid tumor cell lines EL-4 (H-2^b) and C14 (H-2^d), respectively. After preparation of the 37,000 molecular weight papain fragment the antigens were cleaved with CNBr. The H-2K^d antigen yielded four major CNBr fragments whereas the H-2D^b molecule provided six. These CNBr fragments were subjected to partial NH₂-terminal amino acid sequence analysis and aligned by homology to the H-2K^b glycoprotein. Comparison of the structural properties of the H-2K^d and H-2D^b molecules with previously published data on the other known major transplantation antigens of the b and d haplotypes (H-2K^b, H-2D^d and H-2L^d) reveal a marked structural similarity. First, the data show that certain methionine residues have been highly conserved and that cleavage by CNBr at these positions provides an initial strategy for the study of these molecules. Secondly, disulfide-linked peptides obtained after CNBr cleavage could be aligned and the data suggest the presence of disulfide bridges in homologous positions. Third, after CNBr cleavage both the H-2K^d and H-2D^b molecules yielded two glycopeptides which were homologous to glycopeptides from the H-2K^b molecule. Fourth, overall homology for a limited number of comparable positions is about 81% between the H-2K^b and H-2K^d gene products and 88% between the H-2K^b and H-2D^b gene products.     

Villous adenoma of the bile ducts: a case report and a review of the reported cases in Korea

Villous adenomas are benign epithelial lesions with malignant potential which can occur at any site in the gastrointestinal tract. They are usually encountered in the rectum and colon, less frequently in the small bowel and very rarely in the biliary trees. Nine cases of bile duct villous adenomas have been reported in the literature. However, 4 cases of bile duct villous adenomas have been reported in the Korean literature. Recently, we experienced a case of villous adenoma in the common hepatic duct in a 77-year-old man presenting with obstructive jaundice in which preoperative histologic diagnosis of villous adenoma played a critical role in managing this patient. Herein, we present a case report of bile duct villous adenoma and a review of the reported cases in Korea to help define and manage this rare disease entity in the bile ducts. In addition, confusing nomenclature of bile duct adenomas is discussed.     

Serologic ambiguity and allelic frequency of the HLA-B40 family in the Korean population

The most frequently identified HLA-B type in Koreans is HLA-B40 (13.4%). Due to the lack of mono-specific alloantisera and cross reactivity of sera used as typing reagents, discrimination between the serologic splits of B40, B60 and B61, has been a problem in tissue typing laboratories. In this study, an efficient PCR-SSP typing system was established to distinguish B60 and B61 and to assess the difficulty in serologic assignment for these types. The SSP system was also used to elucidate the frequency of B40 alleles (B*4001-B*4008) encoding B40 molecules in the Korean population. Eighty eight unrelated individuals identified serologically as B40 positive were selected from 358 consecutive volunteers from the unrelated bone marrow registry. Seven sets of PCR that amplify exons 2 and 3 of the HLA-B gene using 10 sequence specific primers (SSP) were used for discrimination between B60 and B61, and for B40 allelic typing. A clear discrimination of B60 and B61 was possible in all samples including 48 serologically ambiguous samples (B60 – 14/48; B61 – 34/48) and 5 potentially B40 homozygous samples (B60/B61 heterozygotes – 4/5; B60 homozygote - 1/5). Therefore, the use of a focused SSP approach enhances serologic definition of HLA types in routine clinical testing. In allelic typing, all B60 samples (26) appeared to be B*4001, but B61 samples revealed more heterogeneity (B*4002 – 36/58, B*4003 – 4/58, B*4006 – 18/58). In addition, B*4003 seemed to be closely associated with the A24-Cw3-DRB1*02 haplotype (3/4). The characterization of allele frequency as well as haplotypic association will be helpful in determination of the optimal size of the volunteer marrow donor pool in the Korean population.