During the development of vertebrates, differentiated cells are already programmed to synthesize functional proteins to express their specified cellular functions by receiving several kinds of extracellular signals. By use of the in vitro and in vivo systems for analyzing the molecular mechanisms of antibody synthesis in B-lymphocytes, I have found that an activation of immunoglobulin gene could be involved in the activation of antibody synthesis induced by antigen signals. By developing the cell-free transciptional systems of silk fibroin gene, I have subsequently found that the gene activation could mainly be achieved by the interactions between the defined nucleotide sequences located upstream from the TATA box of the gene and transcriptional factors which can specifically bind to these upstream sequences. To understand an exact role of neuronal cells in the generation of synaptic plasticity, I am now investigating the genetical responses of neuronal cells activated by synaptic transmission. Elucidation of the gene products whose expression could be affected by the synaptic transmission would reveal functional aspects of neuronal cells when they receive several kinds of synaptic inputs. By use of the primary culture of mouse cerebellar granule cells, we have already revealed several aspects of intracellular mechanisms responsible for the glutamatergic responses of the neuronal cells, focusing on an activation of transcriptional factors whose expression could be immediately induced by the glutamatergic inputs. This type of experiments would provide a valuable insight for understanding the cellular and the molecular mechanisms of synaptic plasticity.
Influenza A, B viruses contain 2 viral specific, membrane associated glycoproprotein antigens, hemagglutinin and sialidase. Hemagglutinin is essential for the initial binding of the virus to the cell membrane receptors that contain sialic acid such as gangliosides and sialo-glycoproteins. Hemagglutinin is also important for the intracellular viral uncoating by the low pH fusion processes. The evolution of the influenza viruses and host range variation come from the mutation of hemagglutinin and sialidase genes and change of their sialo-sugar chain recognition together with alteration in the antigenic epitopes. In this report, the molecular mechanism of the relationship between the evolutional change of the viral glycoproteins, especially hemagglutinin molecules and the change of the receptor binding specificity is reported, and also the strategy for the development of a new universal vaccine which generates the antibody whose supervariable region mimics the common receptor sialo-sugar chains for all the subtypes of influenza viruses is also described.
Metabolites of quinotolast in the human, rat and dog urine were isolated chromatographically and their structures were determined spectroscopically. para-Hydroxy substitution to the phenoxyl function of quinotolast, and glucoside or glucuronide conjugate to its tetrazole ring were observed.
A highly specific, sensitive and reproducible high-performance liquid chromatographic method was developed for the determination of a new H2-receptor antagonist, N-[3-[3-(piperidinomethyl) phenoxy] propyl]-2-(2-hydroxyethylthio) acetamide·2-(4-hydroxybenzoyl) benzoate (Z-300), in rat, dog and human plasma, Z-300 base was isolated from the plasma using a Extrelut-1 solid-phase extraction cartridge. The Z-300 base was converted to a fluorescent derivative by the use of 1-anthroyl cyanide in the presence of quinuclidine as catalyst. The derivatized mixture was treated with Sep-pak CN Vac cartridge to remove interferences from endogenous substances. The derivative obtained was separated on a Inertsil ODS-2 column using a acetonitrile-0.2% ammonium acetate-methanol (7 : 6 : 6) containing 0.5 mM dodecyltrimethylammonium bromide (ion-pair reagent) as a mobile phase with a fluorescence detector. The detection limit of Z-300 base in the plasma was 0.5 ng/ml. The calibration curves were linear over the range of 2-200 ng/ml. The method appears to be readily applicable to the study of Z-300 pharmacokinetics in animals and humans.
The amounts of myocardial metallothionein (MT) and heavy metal (Zn, Cu) levels during the early stage of the experimental myocardial infarction model induced by isoproterenol (Isp) administration were measured by an atomic absorption spectrophotometry. MT was measured by the Cdhem method. Myocardial infarction was induced by the administration of 75 mg/kg i.p. of Isp to rats weighing 270±10g. Thirty minutes after Isp injection, Zn and Cu levels began to decrease and 12 h later, reached the minimal values compared with the control value. The level of MT began to increase 3 h after the Isp injection and reached the maximal value at 12 h, although MT remained undetectable in the control myocardial tissue by the Cd-hem method. MT levels in the liver increased and total Zn and Cu were elevated compared with the control value 12 h after Isp administration. These results suggest that MT is produced in the myocardium after Isp administration, and that the roles of MT in the heart and the liver are different. It was thought that a rise in MT was induced for the protection of the myocardial cells to injury.
The serum 4-O-methylpyridoxine (MPN) levels in a 21 months-old patient with gin-nan food poisoning were determined by HPLC. The blood of the patient was taken at 8.5 and 15.5 h after taking about 50 ginkgo albumens. After deproteinization of the serum, the supernatant was pretreated with Sep-pak C18 cartridge and was applied to HPLC. HPLC was performed with a Hibar LiChrosorb RP-18 (4.0 mm i.d.×250 mm, 7μm) using a fluorescence detector (wave length of excitation and fluorescence ; 290 and 400 nm, respectively). The serum MPN level was determined by the absolute calibration method. The determination limit of MPN in the serum was 0.05 μg/ml. The serum MPN concentration was 0.09 μg/ml at 8.5 h after taking ginkgo seeds, and was less than the determination limit of MPN (0.05 μg/ml) at 15.5h. MPN, isolated from the seed of Ginkgo biloba L., is responsible for"gin-nan food poisoning, "and its cardinal symptoms are mainly tonic and/or clonic convulsions and loss of consciousness. Infants are particularly vulnerable. This method may be available for proving the gin-nan food poisoning, chemically.
A simple method using ion-pair high-performance liquid chromatography was established for the rapid and precise determination of synephrine in thirtythree species of oriental pharmaceutical decoctions containing Aurantii Nobilis Pericarpium. An ODS column and a mixed solvent system of water, acetonitrile, sodium dodecyl sulfate and phosphoric acid as a mobile phase were used for the separation. Synephrine was eluted without interference of other coexisting components within 15 min.