Stimulation of the nucleus basalis of Meynert increases diameter of the parenchymal blood vessels in the rat cerebral cortex.

To verify the hypothesis that stimulation of the nucleus basalis of Meynert (NBM) induces vasodilation in the cerebral cortical parenchyma, we investigated whether the diameter of parenchymal blood vessels of rat parietal cortex is increased during stimulation of NBM using histological techniques. The parietal cortex was fixed by immersion fixation in situ during focal electrical stimulation of the NBM, which increased cortical blood flow. Cortical tissues were sectioned horizontally to the cortical surface, and the parenchymal blood vessels were morphometrically analyzed using electron microscopy. Mean inner diameter of the parenchymal blood vessels in NBM stimulated rats (5.51+/-0.33 microm) was significantly larger than that in non-stimulated control rats (4.93+/-0.23 microm). The result suggests that functional vasodilation in the cortical parenchyma during NBM stimulation correlates with histologically observed vasodilation in the cortical parenchyma.

Cloning of an intracellular Poly[D(-)-3-Hydroxybutyrate] depolymerase gene from Ralstonia eutropha H16 and characterization of the gene product.

An intracellular poly[D(-)-3-hydroxybutyrate] (PHB) depolymerase gene (phaZ) has been cloned from Ralstonia eutropha H16 by the shotgun method, sequenced, and characterized. Nucleotide sequence analysis of a 2.3-kbp DNA fragment revealed an open reading frame of 1,260 bp, encoding a protein of 419 amino acids with a predicted molecular mass of 47,316 Da. The crude extract of Escherichia coli containing the PHB depolymerase gene digested artificial amorphous PHB granules and released mainly oligomeric D(-)-3-hydroxybutyrate, with some monomer. The gene product did not hydrolyze crystalline PHB or freeze-dried artificial amorphous PHB granules. The deduced amino acid sequence lacked sequence corresponding to a classical lipase box, Gly-X-Ser-X-Gly. The gene product was expressed in R. eutropha cells concomitant with the synthesis of PHB and localized in PHB granules. Although a mutant of R. eutropha whose phaZ gene was disrupted showed a higher PHB content compared to the wild type in a nutrient-rich medium, it accumulated PHB as much as the wild type did in a nitrogen-free, carbon-rich medium. These results indicate that the cloned phaZ gene encodes an intracellular PHB depolymerase in R. eutropha.

Isolation and identification of dengue viruses by combined use of C6/36 cells and the immune adherence hemagglutination test.

Dengue viruses were isolated in a mosquito cell clone, C6/36, and their serotypes were identified by the immune adherence hemagglutination (IAHA) test. Even when viruses were not cytopathogenic, the IAHA test detected virus growth in the cells.

Antigenic and genetic analysis of A/Hong Kong (H3N2) influenza viruses isolated from swine and man.

Two H3N2 strains of influenza A virus isolated from pigs in Japan and Thailand were characterized antigenically and genetically. A/swine/Wadayama/5/69 (isolated in Japan in 1969) was antigenically similar to a human strain, A/Aichi/2/68, while A/swine/Bangkok/9/78 (a swine isolate in Thailand) was closely related to A/Bangkok/36/78, a contemporary human isolate. Gel electrophoresis and oligonucleotide mapping of the virus RNA revealed genetic similarity between A/swine/Wadayama/5/69 and A/Aichi/2/68, and between A/swine/Bangkok/9/78 and A/Bangkok/36/78, suggesting the derivation of swine H3N2 strains from contemporary human strains.

Isolation and serological characterization of influenza A virus from a pig in Thailand.

A hemagglutinating agent was isolated from a pig in Thailand in 1978 during the early febrile stage of an influenza-like illness and identified as influenza A virus. The isolate contained hemagglutinin and neuraminidase antigens that were antigenically indistinguishable from those of A/Tokyo/6/73 (H3N2), a Port Chalmers-like strain isolated in Japan. Serological tests also indicated that prevalence of H3N2 virus in the swine population in Thailand.

An electron stain for elastic fibers using orcein.

Orcein was found to be useful as an electron-opaque stain for elastic fibers in epoxy-sections. Ultra-thin sections of aorta were treated with elastica stain containing 0.1-0.3% orcein and counterstained in uranyl acetate and lead citrate. Elastic fibers were densely and specifically demonstrated in the stroma and near smooth muscle cells. The result of orcein staining has a comparable appearance under both light and electron microscopes.