Tomiyoshi Ito

Description of Achromobacter xylosoxidans Yabuuchi and Ohyama 1971

More than 70 characters of 55 strains of Achromobacter xylosoxidans were compared with those of the type strain of A. xylosoxidans, ATCC 27061 (= KM 543). Repeated examination of these 55 strains confirmed the stability of the flagellar morphology and biochemical reaction pattern and performed that the species can be recognized by these characters. Two strains of Alcaligenes faecalis, two strains of Alcaligenes denitrificans, five strains of Alcaligenes sp., and five strains of each of King groups IIIa and IIIb were identified as strains of A. xylosoxidans. The base compositions of the deoxyribonucleic acids of 20 strains are given. The cellular fatty acid composition of extractable and bound lipids of five strains was determined. The minimal characters for the identification of strains of A. xylosoxidans are presented.

Role of activated platelets in endotoxin-induced DIC in rats

To clarify whether activated platelets play an important role in the occurrence and exacerbation of disseminated intravascular coagulation (DIC), we investigated the effects of 4 anti-platelet drugs, a PGI2 analog (CS-570), a thromboxane synthetase inhibitor (dazoxiben), a thromboxane receptor antagonist (BM-13177), and ticlopidine, in an experimental DIC model in rats. Experimental DIC was induced by a continuous infusion of lipopolysaccharide (LPS derived from E. coli, 055 B5, 25 mg/kg/hr) for 4 hrs. In the time-course determination of the coagulation parameters and prostanoids, an abrupt increase in TxB2 (a stable metabolite of TxA2) and 6-keto-PGF1 alpha (a stable metabolite of PGI2) was followed by a decrease in platelet count, a prolongation of blood coagulation time, and an increase in fibrinogen/fibrin degradation products (FDP). Four hours after the start of LPS infusion, the rats were considered to be in the state of DIC. The effects of the anti-platelet drugs were investigated 4 hrs after the start of LPS infusion. CS-570 and ticlopidine ameliorated DIC in a dose-dependent manner. CS-570 (10 micrograms/kg/min) improved DIC in the platelet count, prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fbg), and FDP, without affecting TxB2 and 6-keto-PGF1 alpha formation. Ticlopidine (200 mg/kg, i.p.) prevented the exacerbation of DIC in such item parameters as platelet count, APTT, and FDP. Both dazoxiben and BM-13177 (30 mg/kg, i.p.) ameliorated DIC in following parameters as platelet count, APTT and FDP. Dazoxiben, but not BM-13177, significantly inhibited the increase in TxB2 concentration at 4 hr. These observations suggest that drugs which inhibit platelet activation by a TxA2-dependent route are effective in improving DIC induced by LPS, and that drugs which inhibit multiple platelet-activating routes improve DIC in more item parameters than drugs which inhibit only the TxA2-dependent activating route. Consequently, it is concluded that activated platelets might play an important role in the occurrence and exacerbation of DIC induced by LPS, and that one of the roles of TxA2 in DIC is to activate platelets.

RS-5186, a novel thromboxane synthetase inhibitor with a potent and extended duration of action.

RS-5186, sodium 6-[2-[1-(1H)-imidazolyl]methyl-4,5-dihydrobenzo[b]thiophene]- carboxylate, inhibited platelet thromboxane A2 (TXA2) synthetase with IC50 values of 6 nM and 13 nM for human and rabbit microsomes, respectively. It had a selectivity for TXA2 synthetase 10(5)-fold greater than that for cyclooxygenase, PGI2 synthetase, 5-lipoxygenase and phospholipase A2. When administered orally or intravenously to dogs at 1 mg/kg, RS-5186 suppressed serum TXB2 levels almost completely with sustained duration of action: the suppression during 0.5 hr to 8 hr after dosing was more than 90%, and was 70-80% at 24 hr. Similar suppression of serum TXB2 levels was observed in rats and rabbits. Such suppression by RS-5186 was more potent than that by OKY-046 and CV-4151. Serial administration of RS-5186 (0.1 mg/kg/day p.o.) to dogs for 7 days decreased the serum TXB2 levels constantly during the medication, and no rebound phenomenon was observed after the medication was stopped. In a thrombotic model induced by sodium arachidonate injection in rabbits, RS-5186 at 1 mg/kg p.o. completely protected against sudden death (ED50 = 0.12 mg/kg, 1 hr after dosing) and this protective effect extended over 8 hr. All these results show that RS-5186 is a potent and highly selective TXA2 synthetase inhibitor with a long duration of action, and suggest that the compound could be useful in diseases where TXA2 is involved.

In Vitro Antimicrobial Activity of Ceftizoxime Against Glucose-Nonfermentative Gram-Negative Rods

Ceftizoxime, a new cephalosporin, was active against Pseudomonas cepacia, Flavobacterium meningosepticum, Alcaligenes faecalis, and Acinetobacter calcoaceticus and was more potent against Pseudomonas aeruginosa and Pseudomonas putida than was carbenicillin.

Electron Microscopic Observation of the Budding Maturation of Group B Arboviruses

In the maturation process of group A arboviruses as generally known immature particles are enveloped while passing into the lumen of cytoplasmic vacuoles or while being extruded through the cell membrane (2). Differing from group A arboviruses, numerous efforts by many investigators (1, 3-5, 7, 8, 10-14) have failed to provide enough informations on the morphological maturation process of group B arboviruses. Our study has been focused on an electron microscopic insight into such maturation process of group B arboviruses by which the envelope is formed around the nucleocapsid. Three mouse-adapted virus strains, Japanese encephalitis virus ( JEV) JaGAr-01, dengue virus (DV) type 4 H-241 (MB-2), and yellow fever virus (YFV) 17D, were used in this experiment. Vero cells were grown in Eagles minimum essential medium added with calf serum in 10%, and the infected cells were maintained with a decreased concentration, 2%, of calf serum. Monolayered Vero cell cultures were inoculated with each virus suspension prepared by the following procedure; a 10% suckling mouse brain emulsion made with Dulbeccos phosphate-buffered saline (PBS) was centrifuged at 1,000 rpm for 5 min, and the supernatant was diluted to 1:100 with PBS. The infected Vero cells were frozen and thawed at harvest to use the supernatant as inocula for the next passage. The culture interval was 4 days for the first passage and 48 hr after the 2nd passage. Infected Vero cells at various stages were subjected to fixation with 2% glutaraldehyde and then with 1% OsO4, followed by dehydration with ethanol in serial concentrations. Peroxidase-labeled antibody and ferritin-labeled antibody, specific for each of the 3 virus strains used, were prepared for immuno-electron microscopy according to Nakane and Kawaoi (9) and Singer and Schick (15). The specific fluorescence for JEV was observed by the fluorescent antibody technique at the perinuclear region of cytoplasm of Vero cells, 15 hr after inoculation of virus. The development of specific immunofluorescence was slightly delayed in DV and YFV, when compared with that of JEV. The specific fluorescence for each virus extended gradually into the cytoplasmic area from the juxtanuclear to