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Biomedical subjects

S Oda

Publications and source records attributed to S Oda.

At least 397 records · Page 22Linked to original sources
PubMed1988

Neurotransmitter receptors of the rolling mouse Nagoya: a quantitative autoradiographic study.

The distribution of neurotransmitter and neuromodulator receptors was studied in the brain of the rolling mouse Nagoya (RMN) and in controls, using in vitro receptor autoradiography. Quantitative autoradiography was used to map adenosine A1 (labeled with [3H]cyclohexyladenosine), GABAA [( 3H]muscimol), opiate [( 3H]naloxone), L-glutamate [( 3H]L-glutamate), benzodiazepine [( 3H]flunitrazepam), and muscarinic cholinergic [( 3H]quinuclidinyl benzilate) receptors. In the cerebellar cortex, GABAA and adenosine A1 binding sites were significantly reduced in the RMN, whereas other transmitter binding sites were not significantly altered. Adenosine A1 binding sites were also reduced in the cerebral cortex and caudate-putamen. Benzodiazepine binding was significantly decreased in the cerebral cortex and increased in the CA1 subfield of the hippocampus. These results suggest that neurochemical alterations in the caudate-putamen as well as in the cerebellar cortex play important roles in the ataxia and motor dysfunction of the RMN.

Animals↗
PubMed1988

Purification and characterization of a lectin-like molecule specific for galactose/N-acetyl-galactosamine from tumoricidal macrophages.

A lectin-like molecule (macrophage lectin) was purified from murine peritoneal exudate macrophages which had been induced with an antitumor streptococcal preparation, OK-432. The purified macrophage lectin from both 3H-labeled and unlabeled macrophages after rechromatography on a beta-D-galactose-Bio-Gel P-100 column gave a broad single band corresponding to 45-60 kDa on SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The broadness of this band was due to high N-glycosylation of the lectin, because the lectin gave a compact band corresponding to 35 kDa on SDS-PAGE after deglycosylation. The lectin required Ca2+ for binding and showed an optimum pH of around 6. The sugar specificity of the lectin was examined by means of an inhibition assay using simple sugars and neoglycoproteins. The lectin was found to be specific for D-galactose/N-acetyl-D-galactosamine, and not inhibited with D-mannose or N-acetyl-D-glucosamine at all. The lectin was detected on the surface of OK-432-elicited and thioglycolate-elicited macrophages, but it was not detected on resident macrophages. Moreover, the binding of tumor cells to macrophages was inhibited by the addition of the purified lectin to the binding mixture. These results suggest that this lectin is expressed on the surface of activated macrophages, and that it participates in the interaction between tumoricidal macrophages and tumor cells.

Animals↗
PubMed1988

Adrenergic modulation of pancreatic glucagon and insulin secretion in sheep.

The effect of intravenous infusion of epinephrine, either alone or together with various doses of phentolamine or propranolol, on the secretion of both glucagon and insulin was determined in six sheep. Intravenous infusion of epinephrine alone caused increases in plasma glucagon and glucose concentrations and produced a slight but significant decrease in plasma insulin concentration. The concomitant infusion of propranolol and epinephrine augmented glucagon release and inhibited insulin secretion. Combined propranolol plus epinephrine infusion also caused a marked hyperglycemia. The concomitant infusion of phentolamine and epinephrine produced slight inhibition of glucagon secretion and markedly promoted insulin secretion. Epinephrine-induced hyperglycemia was eliminated by phentolamine infusion. The effects of isoproterenol infusion on plasma glucagon, insulin, and glucose concentrations were similar to that caused by the concomitant infusion of phentolamine and epinephrine. The effects of isoproterenol were abolished by the infusion of propranolol. It is concluded that an alpha-receptor mechanism is the most important component of adrenergic modulation of pancreatic glucagon secretion, whereas beta-receptor activation stimulates and alpha-receptor activation inhibits insulin secretion in sheep.

Adrenergic alpha-Antagonists↗
PubMed1988

[Antibacterial activities of monobactams against fresh clinical isolates].

Antibacterial activities of monobactam antibiotics (carumonam (CRMN) and aztreonam (AZT] against Gram-negative bacilli isolated from inpatients in the latter half of 1987 were investigated using penicillin (PC: piperacillin (PIPC], cephems (CEPs: ceftazidime (CAZ), cefotaxime (CTX), latamoxef (LMOX), cefsulodin (CFS], carbapenem (imipenem (IPM] and pyridonecarboxylic acids (norfloxacin (NFLX) and ofloxacin (OFLX] as reference antibiotics. A total of 400 strains of 13 species, i.e. Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia rettgeri, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Pseudomonas aeruginosa and Haemophilus influenzae, were used as test strains. 1. CRMN and AZT, both monobactam antibiotics, were roughly comparable in their activities and no resistant strain to these antibiotics were found among isolates of E. coli, Klebsiella spp., Proteus spp., M. morganii, P. rettgeri or H. influenzae and few resistant strains were observed among isolates of S. marcescens. On the other hand, isolates of C. freundii, Enterobacter spp. and P. aeruginosa included rather numerous strains resistant to the monobactam antibiotics. Among these cases, whereas R strains, i.e. resistant strains showing MICs greater than or equal to 50 micrograms/ml, accounted for a large proportion of strains resistant to PC and CEPs, I strains, i.e. intermediately resistant strains showing MICs between 12.5 and 25 micrograms/ml, accounted for a large proportion of strains resistant to the monobactam antibiotics. 2. Strains resistant to PIPC, a PC, were detected with high and more or less uniform frequencies over the entire spectrum of the isolates examined. 3. Antibacterial activities of CEPs varied against different bacterial species. While strains resistant to CTX, CAZ and LMOX were commonly detected with high frequencies among isolates of C. freundii, Enterobacter spp. and S. marcescens, large percentages of LMOX-resistant strains of C. freundii and Enterobacter spp. were of the I type. CTX-resistant strains were also found among isolates of P. vulgaris and M. morganii. Proportions of CEP-resistant strains of P. aeruginosa were 28% for CFS and 12% for CAZ. 4. No or few strains among the isolates of 13 species investigated were resistant to IPM, a carbapenem antibiotic, which showed the most stable antibacterial activity, but it was less active than monobactam antibiotics and CEPs against Klebsiella spp., P. mirabilis and H. influenzae.(ABSTRACT TRUNCATED AT 400 WORDS)

4-Quinolones↗
PubMed1988

[Antibacterial activity of gentamicin against clinical isolates in pediatrics].

Antibacterial activity of gentamicin (GM), along with activities of other aminoglycosides and beta-lactams, was studied against clinical isolates collected from pediatric patients during a period of May 1986-April 1987. 1. GM-resistance was noted in 22% of Staphylococcus aureus, 6% of Proteus vulgaris, 8% of Morganella morganii, 40% of Providencia spp., 6% of Enterobacter spp., 14% of Serratia marcescens, and 14% of Pseudomonas aeruginosa isolates. No GM-resistance was observed with isolates of Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. 2. The antibacterial activity of GM against clinical isolates from pediatric patients was found to be comparable to its activity against clinical isolates from adults studied at the same time. 3. The majority of GM-resistant strains of S. aureus were MCRSA, and the GM-resistant strains of S. marcescens and P. aeruginosa were found also to be resistant to multiple drugs. 4. GM-resistant strains were found at relatively high rates (14-22%) in S. aureus, S. marcescens and P. aeruginosa. These rates did not increase compared to the rates observed in the first half of the 1980's. 5. GM was considered to have poor antibacterial activity against genus Providencia. It is concluded from above results that GM still maintains effective antibacterial activity against many of causative organisms of infections in both adults and children.

Anti-Bacterial Agents↗
PubMed1988

[Antimicrobial activities of sultamicillin against clinical isolates from upper respiratory tract infections].

Sultamicillin (SBTPC) is a mutual prodrug in which ampicillin (ABPC) and a potent beta-lactamase inhibitor sulbactam (SBT) are ester-bound in an equimolar ratio. SBTPC is hydrolyzed during absorption after oral administration to provide ABPC and SBT for systemic circulation. In the present study, the antimicrobial activities of SBTPC against 50 isolates each of 6 species (Staphylococcus aureus, Klebsiella pneumoniae subsp. pneumoniae, Branhamella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes) of bacteria freshly obtained from upper respiratory tract infections were examined in relation to their bacterial beta-lactamase producing abilities. beta-Lactamase producing strains were identified using the acidometry disc method with benzylpenicillin (PCG) of cefazolin (CEZ) as a substrate, and their frequencies of appearance were calculated as follows: S. aureus 86%; K. pneumoniae subsp. pneumoniae 100%; B. catarrhalis 68%; H. influenzae 24%. Fourteen per cent of S. aureus strains examined were beta-lactamase positive using both PCG and CEZ acidometry discs. SBTPC, however, demonstrated excellent antimicrobial activities even against these beta-lactamase producing strains. Good activities were observed especially against those bacterial strains producing penicillinase (PCase). Average MIC80 values of SBTPC were 3.13 micrograms/ml for S. aureus and K. pneumoniae subsp. pneumoniae, 0.39 micrograms/ml for B. catarrhalis and H. influenzae, 0.05 micrograms/ml for S. pneumoniae and 0.025 micrograms/ml for S. pyogenes. As SBTPC was shown to possess excellent antimicrobial activities against PCase producing strains, the enhancement in activities of SBTPC compared to ABPC alone can be attributed to the inhibition of beta-lactamase by SBT which, as noted above, is a component of SBTPC in an equimolar ratio to ABPC.

Acute Disease↗
PubMed1988

[Antimicrobial activity of sultamicillin against clinical isolates from upper respiratory tract infections II].

In an attempt to examine the effect of sulbactam (SBT) on beta-lactamase activity, three hundred clinical isolates from the infected upper respiratory tract were tested for MICs and disk sensitivities of ampicillin (ABPC) and sultamicillin (SBTPC). beta-lactamase production was tested using the acidometry disk method (beta-Check, Taito Pfizer Co.). For strains such as Klebsiella spp. which form mucoid type colonies, we used the SS culture medium which, by reducing the influence of huge amounts of capsular material, allows a better reaction to the acidometry disk. Penicillinase, produced by Branhamella catarrhalis, Haemophilus influenzae, Neisseria spp., etc. was detected clearly by direct application of portions of colonies onto acidometry disks. For cephalosporinase, however, a direct application of such fractions resulted in weak reactions. We, therefore, used fractions which had undergone the enzyme induction, and obtained better reactions. Sensitivities of tested bacteria to ABPC and SBTPC were inversely related to MIC values. beta-Lactamase-producing strains showed weaker sensitivity to ABPC than non-producing strains. To SBTPC, however, beta-lactamase-producing strains and non-producing strains showed very similar sensitivity. We thus confirmed that the inhibitory action of SBT to beta-lactamase can well be demonstrated using the disk sensitivity method.

Ampicillin↗
PubMed1987

[Clinical significance of serum ribonuclease (RNase) assay in acute leukemia].

The clinical significance of serum ribonuclease (RNase) assay in acute leukemia was studied. Serum RNases were assayed by the method of Akagi et al. with slight modifications in the serum samples obtained from 50 cases of healthy subjects, 55 cases of acute leukemia before therapy, 18 chronic myelocytic leukemia before therapy, 13 chronic myelocytic leukemia under treatment and 20 reactive leukocytosis. The ratio of acid RNase to alkaline RNase activities (Ac/Al ratio) was statistically increased in acute promyelocytic leukemia, acute myeloblastic leukemia [M2], acute myelocytic leukemia and erythroleukemia (leukemic stage) compared with those in healthy subjects (P less than 0.001). All cases of acute promyelocytic leukemia and most of the acute myeloblastic leukemia [M2], acute myelomonocytic leukemia and erythroleukemia cases had an Ac/Al ratio of above 1.0. In remission of acute leukemia, it is noteworthy that acid and alkaline activities showed no substantial difference from those of healthy subjects. While, on relapse of acute leukemia cases, showing Ac/Al ratio above 1.0 in pretreatment state, Ac/Al ratio increased to above 1.0. Thus, the assay of serum RNases and the calculation of Ac/Al ratio might be an additional method for diagnosing acute leukemia and for assessing their remission and recurrence in some type of acute leukemia.

Acute Disease↗
PubMed1987

The effect of recombinant erythropoietin on murine megakaryocyte colony formation.

We investigated the effect of a recombinant human erythropoietin preparation (recombinant Epo) on murine megakaryocyte (MK) colony formation in serum-free and serum-containing culture systems, in order to study the relationship between Epo and megakaryopoiesis. Pokeweed mitogen spleen-conditioned medium (PWM-SCM), a standard source of MK colony stimulator, dose-dependently stimulated MK colony formation in the two culture systems. The plating efficiency of serum-free cultures was almost equal to that of cultures containing serum. Recombinant Epo also dose dependently stimulated MK colony formation in serum-containing cultures. However, in serum-free cultures recombinant Epo alone did not stimulate the growth of MK colonies; with the addition of fetal calf serum (FCS) to the serum-free cultures, recombinant Epo induced the growth of MK colonies. Furthermore, recombinant Epo enhanced MK colony formation through the stimulation of PWM-SCM or murine interleukin 3 (IL-3) in serum-free cultures. Our data show that Epo can act as a stimulator of megakaryopoiesis in collaboration with a factor in serum, or with an MK colony stimulator such as IL-3.

Animals↗
PubMed1987

Hydroxylation of fatty acids and alcohols by hepatic microsomal cytochrome P-450 system from the Mongolian gerbil.

The liver microsomes of the Mongolian gerbil Meriones unguiculatus catalyzed the hydroxylation of various saturated fatty acids (C8-c18), alcohols (C12 and C16) and hydrocarbon (C12) to the corresponding omega- and (omega-1)-hydroxy derivatives. Lauric acid was hydroxylated most effectively among saturated fatty acids and the order of activity as hydroxylation substrates was C12 greater than C14 greater than C13 greater than C16 greater than C10 greater than C18 greater than C8. The specific activity of laurate hydroxylation (5.99 nmol/mg microsomal protein/min) in gerbil liver microsomes was higher than that observed in other species. 1-Dodecanol was also hydroxylated very effectively (4.58 nmol/mg microsomal protein/min) by gerbil liver microsomes, but in general the hydroxylation rates for fatty alcohols were much lower than those for the corresponding acids. It was found from both inhibitor and cofactor studies that the enzyme catalyzing the hydroxylation of fatty acids and alcohols in the liver microsomes of the Mongolian gerbil was a typical cytochrome P-450-linked monooxygenase, and at least two different cytochrome P-450 species were involved in the hydroxylation.

Animals↗
PubMed1987

The mouse eye lens obsolescence (Elo) mutant: studies on crystallin gene expression and linkage analysis between the mutant locus and the gamma-crystallin genes.

Previous studies showed that the mouse Elo (eye lens obsolescence) mutation is located on chromosome 1, at a site near the Len-1 locus, which is defined by a set of polymorphic gamma-crystallin proteins. To investigate further the relationship between Elo and the gamma-crystallins, we have examined the steady-state levels of gamma-crystallin transcripts in normal and mutant eyes and analyzed the linkage relationship between the Elo locus and the gamma-crystallin genes. Our data showed that, while gamma-crystallin mRNA levels are preferentially reduced in the mutant eyes, the mutation does not seem to map within the gamma-crystallin gene cluster. The distance between Elo and the gamma 6 gene (the most proximal gamma-crystallin gene member) is estimated to be 1.4 +/- 0.9 cM, whereas that between gamma 6 and the distantly linked gamma 2 gene is 2.7 +/- 1.3 cM. Our data also suggest the possibility of recombination hot spots with the gamma-crystallin gene cluster.

Alleles↗