Search PubMed⌕ Search

Biomedical subjects

H Kamiya

Publications and source records attributed to H Kamiya.

At least 271 records · Page 15Linked to original sources
PubMed1993

The in vivo and in vitro postantibiotic effect of aminoglycosides using a clinically isolated micro-organism.

We reported a case of abscess in which Serratia marcescens was isolated as the causative organism. We measured the postantibiotic effect (PAE) of dibekacin (DKB) and gentamicin (GM) against S. marcescens and studied the relationship between the clinical effect and the PAE. The minimal inhibitory concentration (MIC) of DKB against S. marcescens was 6.25 micrograms/mL and the serum concentration 30 min after infusion of 100 mg DKB was 5.99 micrograms/mL. The abscess was cured by the administration of DKB every 12 h. The PAE in vivo was 2.5, 2.9 and 3.3 h when DKB was administered at 50 mg/kg, 100 mg/kg and 200 mg/kg, respectively. This PAE is one of the reasons that infection can be effectively treated with intermittent administration, even if the serum concentration is below the MIC.

Abscess↗
PubMed1993

Inhibition of c-Ha-ras gene expression by hammerhead ribozymes containing a stable C(UUCG)G hairpin loop.

Catalytic RNAs recognize specific sequences of RNA and cleave at a specific site. In this study, we designed hammerhead ribozymes with a thermodynamically stable loop of the sequence 5'C(UUCG)G3' to prevent the aggregation of ribozymes with hammerhead structures. The cleavage activities of these ribozymes were examined using a synthetic pentadecamer with the sequence for the c-Ha-ras mRNA mutated at codon 12 (GGU-->GUU). For in vivo studies, we constructed a plasmid which expressed a highly active ribozyme targeted against the mutated c-Ha-ras mRNA. When this ribozyme-encoding gene and the activated c-Ha-ras gene were cotransfected into NIH3T3 cells, morphologically normal cells were obtained. We also determined that the expression of the c-Ha-ras gene was inhibited in these cells. These results show that ribozymes containing this stable hairpin loop are useful for the regulation of specific gene expression in vivo.

3T3 Cells↗
PubMed1993

Pharmacological profiles of muscarinic receptors in the longitudinal smooth muscle of guinea pig ileum.

We have examined the pharmacological subtypes of muscarinic receptors mediating phosphoinositide hydrolysis and contraction in the longitudinal smooth muscle of guinea pig ileum with the use of muscarinic antagonists. Carbachol increased the formation of 3H-inositol phosphates (IPs) in a dose-dependent manner in both ileal smooth muscle and the frontal cortex of rats. The rank order of muscarinic antagonists for inhibition of IP formation induced by carbachol was 4-DAMP = atropine > pirenzepine > AF-DX 116 in guinea pig ileal smooth muscle. In ileal smooth muscle, the inhibition by the M1 antagonist pirenzepine was about 15 times less than that by atropine. However, in the rat frontal cortex, the inhibition by pirenzepine was only about 3 times less than that by atropine. The inhibitory effect of the M2 antagonist AF-DX 116 was weak in both ileal muscle and the frontal cortex. The M3 antagonist 4-DAMP strongly inhibited carbachol-induced IP formation in ileal smooth muscle. The rank order of muscarinic antagonists for inhibition of contraction induced by 10(-7) M carbachol was atropine > or = 4-DAMP > pirenzepine > AF-DX 116. These results suggest that both IP formation and the contractile response induced by muscarinic agonists are mediated through the muscarinic M3 subtype in guinea pig ileum.

Animals↗
PubMed1993

Cloning of VH and VL genes for antibodies specific for pyrimidine photo dimers.

We have prepared two types of cDNAs encoding mouse immunoglobulin heavy (VH) and light (VL) chain variable (V) domains against UV-induced DNA damage by the polymerase chain reaction (PCR). The amplified cDNA was cloned for sequencing and expression, and the nucleotide sequences of the V domains were determined. The deduced amino acid sequences of the complementarity-determining regions (CDRs) indicated that CDR3 of the VH domain and CDR2 of the VL domain might be concerned with the recognition of photolesions.

Antibodies↗
PubMed1993

[Clinical evaluation of S-1108 in children].

We administered S-1108 to 16 children with ages ranging from 7 month to 15 years at doses between 1.8 and 6.0 mg/kg x 3/day for 3 to 13 days. We evaluated the efficacy and safety of S-1108 in 11 children with respiratory tract infections, 3 urinary tract infections, and 2 skin infections. The efficacy rate of S-1108 was 100% and bacteriological eradication rate was 83.3%. No adverse effects were observed. These results suggested that S-1108 could be used safely in children.

Adolescent↗
PubMed1992

Central pressor actions of tachykinin NK-3 receptor in the paraventricular nucleus of the rat hypothalamus.

The central pressor actions of the tachykinin NK-3 receptor in the paraventricular nucleus (PVN) of the hypothalamus were examined in anesthetized rats. In forebrain-restricted animals, the selective tachykinin NK-3 receptor agonist senktide (10 micrograms, i.c.v.) increased the blood pressure, and this pressor response was more potent than in control animals. Injection of senktide into the PVN also increased the blood pressure, and this pressor response was inhibited by pretreatment with the vasopressin V1 receptor antagonist (10 micrograms/kg, i.v.). These results suggest that central injection of senktide stimulated the NK-3 receptor in the PVN of the hypothalamus, and increased blood pressure by inducing release of vasopressin from the pituitary gland.

Animals↗
PubMed1992

An abasic site analogue activates a c-Ha-ras gene by a point mutation at modified and adjacent positions.

Synthetic c-Ha-ras genes with an analogue of an abasic site in the first or the second position of codon 12, or in the second position of codon 61 were constructed and transfected into NIH3T3 cells. The genes with the lesions in codon 12 exhibited more focus formation than a normal c-Ha-ras gene, while the gene with the lesion in codon 61 did not. Transformed cells were isolated from the foci, and the c-Ha-ras genes present in the transformants were analysed. A point mutation to A in the modified position was found most frequently in the cases of ras genes modified in codon 12. Surprisingly, point mutations in the adjacent position were also detected. These results indicate that dTMP, and not dAMP, was mainly incorporated into the sites opposite to the abasic site analogue, and that incorrect deoxynucleotides were incorporated in the position adjacent to the abasic site analogue.

3T3 Cells↗
PubMed1992

Ribozymes designed to inhibit transformation of NIH3T3 cells by the activated c-Ha-ras gene.

We have designed hammerhead ribozymes that cleave c-Ha-ras mRNA mutated at codon 12 (GGU----GUU). Plasmids containing the ribozyme-encoding genes were expressed under the control of the long terminal repeats of Rous sarcoma virus in NIH3T3 cells transfected with the activated c-Ha-ras gene. These ribozymes were found to inhibit formation of foci (by about 50%) by cleaving the oncogene mRNA, rather than by hybridizing to it. Furthermore, when the activated c-Ha-ras gene was cotransfected with the ribozyme-encoding gene, three morphologically flat colonies were found and isolated. We also found that expression of c-Ha-ras was suppressed in cells containing ribozymes.

3T3 Cells↗
PubMed1992

c-Ha-ras containing 8-hydroxyguanine at codon 12 induces point mutations at the modified and adjacent positions.

To determine the type of mutation induced by 8-hydroxyguanine in a mammalian system, we examined the mutations induced by a synthetic c-Ha-ras protooncogene containing 8-hydroxyguanine in the second position of codon 12 (GGC) in NIH3T3 cells. Transfection of this gene significantly increased the number of transformed foci. The c-Ha-ras gene present in these foci was analyzed by the polymerase chain reaction-restriction enzyme method. Interestingly, sequence analysis revealed random mutations at the modified site (G----T, G----A, and G----C) as well as mutations of the adjacent G on the 5'-side of 8-hydroxyguanine (G----A and G----T).

3T3 Cells↗
PubMed1992

Role of NK-1 receptor in central cardiovascular regulation in rats: studies on a novel non-peptide antagonist, CP-96,345, of substance P NK-1 receptor.

CP-96,345[(2S,3S)-cis-2-(diphenylmethyl)-N-[(2-methoxyphenyl)- methyl]-1-azabicyclo [2.2.2] octan-3-amine] was recently discovered to be a nonpeptide substance P (SP) antagonist. We examined the effects of CP-96,345 on the central cardiovascular responses to tachykinin peptides in anesthetized rats. CP-96,345 (200 nmol, i.c.v.) inhibited the pressor responses of the NK-1 receptor-selective agonist GR 73632 (0.5 nmol, i.c.v.) and SP (7 nmol, i.c.v.). It also inhibited the increase in blood pressure elicited by neurokinin A (7 nmol, i.c.v.). However, it had no effect on the earlier pressor response induced by neuropeptide gamma (l nmol, i.c.v.) or by a selective NK-3 agonist senktide (1 nmol, i.c.v.). These findings suggest that SP (i.c.v.) induces pressor responses via the NK-1 receptor, and that the pressor response to neurokinin A may also be mediated by the NK-1 receptor in the brain.

Animals↗
PubMed1992

The amino-acid sequence of a lectin from conger eel, Conger myriaster, skin mucus.

The amino-acid sequence of a beta-galactoside-binding lectin isolated from the skin mucus of the conger eel Conger myriaster was determined. The lectin (30 kDa) was composed of two identical subunits of 135 amino acid residues with N-acetylserine at the N-terminus and no half-cystinyl residue. It was a 30-34% sequence identical to vertebrate beta-galactoside-binding lectin and proved to be a member of the S-type lectin family.

Amino Acid Sequence↗
PubMed1992

Enhancement of postsynaptic responsiveness during long-term potentiation of mossy fiber synapses in guinea pig hippocampus.

The primary site responsible for the long-lasting enhancement of synaptic transmission during long-term potentiation (LTP) was examined by quantal analysis of excitatory postsynaptic potentials in thin sections of the guinea pig hippocampus. With induction of LTP in mossy fiber synapses, estimated values of quantal amplitude (q) and Pascal parameters p and r were increased significantly. No increases in quantal content (m) were detected. The magnitude of increases in q was almost equal to that of LTP. These results indicate that LTP in mossy fiber synapses results from increases in responsiveness of postsynaptic neurons.

Afferent Pathways↗
PubMed1992

Induction of mutation of a synthetic c-Ha-ras gene containing hypoxanthine.

The second base of codon 61 of a synthetic c-Ha-ras gene was replaced with a hypoxanthine residue in a site-specific manner. Transfection of this gene into NIH3T3 cells by the calcium phosphate procedure resulted in increased focus formation. Total DNA was extracted from transformed cells, and the sequences of the inserted c-Ha-ras DNA were analyzed by the polymerase chain reaction-single-strand conformation polymorphism method. Mutations with A (or hypoxanthine) to G transition were detected exclusively. These results suggest that the synthetic c-Ha-ras gene can be used for investigations of mutagenesis caused by DNA lesions.

3T3 Cells↗
PubMed1992

Immunogenicity and reactogenicity of Takeda acellular pertussis-component diphtheria-tetanus-pertussis vaccine in 2- and 3-month-old children in Japan.

OBJECTIVE: To compare the reactogenicity and immune response to the Takeda acellular pertussis-component diphtheria-tetanus-pertussis (APDT) vaccine in children when immunization commenced at 2 months (group A) vs 3 months (group B) of age. DESIGN: Longitudinal, nonblinded, comparative study. SETTING: Pediatric well-child clinics. PARTICIPANTS: Healthy 50- to 98-day-old infants. RESULTS: Good antibody responses to lymphocytosis-promoting factor, filamentous hemagglutinin, agglutinogens, and pertactin occurred in both age groups after both the third and fourth vaccine doses. Both young age and transplacentally acquired maternal antibody independently and together have a suppressive effect on the response to the four antigens in this APDT vaccine. However, these effects appear to be minor. Vaccine reactions were mild; group A children had slightly but not significantly higher rates than group B children. CONCLUSION: The present US diphtheria and tetanus toxoids and pertussis vaccine immunization schedule should also be satisfactory with this acellular pertussis component vaccine.

Age Factors↗
PubMed1992

An empirical test for the reliability of quantal analysis based on Pascal statistics.

We have previously shown that amplitude distributions of excitatory postsynaptic potentials (EPSPs) can be better described by Pascal distribution when the mean quantal content (m) is not stationary but fluctuating according to gamma distribution. We have developed the procedure of estimating quantal parameters by the method of maximum likelihood. In this study, we examined empirically the reliability of this quantal parameter estimation procedure by using Monte Carlo simulations. The reliability was evaluated by absolute values of error (magnitude of error) of estimated parameters relative to the known 'true' parameters. The mean values of relative magnitude of error were relatively small unless the probability of failures was too large (greater than 0.7) or too small (less than 0.1). The values of relative magnitude of error became smaller in association with increases in the sample size. When the probability of failure was between 0.1 and 0.7, the sample size was 1000, coefficient of variation of quantal size was 0.45, the values of relative magnitude of error of estimated parameters were below 0.1. These results mean that this procedure gives relatively reliable estimates of quantal parameters with the limitation that the probability of failure is neither too large (greater than 0.7) nor too small (less than 0.1); it is preferable that the sample size is as large as 1000.

Evoked Potentials↗
PubMed1992

Flow cytometric analysis of effects of cytokines on the expression of varicella-zoster virus glycoproteins.

Varicella-zoster virus (VZV)-infected human embryonic fibroblast (HEF) cells were stained with monoclonal antibodies directed against VZV glycoprotein I, II and IV, and then labeled with fluorescein isothiocyanate (FITC)-conjugated goat anti-mouse IgG. The cells were analyzed by flow cytometry. VZV-infected cells expressing VZV glycoproteins were clearly distinguished from uninfected cells. This method was useful for analyzing expression of VZV glycoproteins in different experimental conditions. Interferon alpha, beta, and gamma and tumor necrosis factor (TNF)-alpha reduced the percentage of positive cells and the mean fluorescence intensity of the cells expressing VZV glycoproteins. Interleukin(IL)-1 beta, IL-6 and TNF-beta had little effect on the expression of VZV glycoproteins.

Cells, Cultured↗