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Biomedical subjects

H Kamiya

Publications and source records attributed to H Kamiya.

At least 253 records · Page 14Linked to original sources
PubMed1994

Preparation of a photoactivatable fluorescent derivative of lactose and its application to photoaffinity labeling of a conger eel lectin.

A photoactivatable heterobifunctional fluorescent reagent, 1-azido-5-naphthalene sulfonyl (ANS) hydrazide, was synthesized and characterized. ANS-hydrazide reacted with lactose to form a photoactivatable hydrazone. The derivative (ANS-lactose) had the same binding affinity for a conger eel lectin as lactose judging from the hemagglutinating-inhibition assay with rabbit erythrocytes. ANS-lactose was used for photoaffinity labeling of a conger eel lectin. The photolabeled lectin was digested with chymotrypsin to isolate photolabeled peptides by reversed-phase HPLC by monitoring fluorescence. A major labeled peptide was located at positions 31-45 in the lectin by amino acid analysis and N-terminal sequencing. The identified segment was close to the highly conserved region throughout animal beta-galactoside-binding lectins.

Affinity Labels↗
PubMed1994

Gas-phase microsequencing of peptides and proteins with a fluorescent Edman-type reagent, fluorescein isothiocyanate.

A fluorescent Edman-type reagent, fluorescein isothiocyanate (FITC), was adapted to a gas-phase sequencer fitted with a miniature reaction chamber. Fluorescein thiohydantion amino acids were identified by on-line gradient HPLC with fluorescence monitoring. The optimized protocol for the coupling reaction using FITC and phenylisothiocyanate, and the degree of washing to remove the excess reagents were established. Myoglobin (5 pmol) and lysozyme (5 pmol) were analyzed by the sequencer to obtain a 35-51% initial yield (I.Y.) and 82-88% repetitive yield (R.Y.) for the former, and 51-66% I.Y. and 91-92% R.Y. for the latter. These figures permitted 20-25 amino acid residues to be identified from the N-terminus of 5 pmol samples applied to the sequencer.

Amino Acid Sequence↗
PubMed1994

[Pharmacokinetic and clinical studies of cefozopran in the field of pediatrics].

Cefozopran (CZOP) was administered intravenously to 22 infants (aged 3 months to 15 years) with infections excluding suppurative meningitis in doses of 10 to 40 mg/kg 3 to 4 times daily for periods of 3 to 16 days and its efficacy and safety in infantile infections as well as pharmacokinetic parameters were determined. The half-lives of CZOP after intravenous administration at doses of 10, 20 and 40 mg/kg were 2.84, 2.36 +/- 0.67, and 2.48 hours, respectively. The rates of recovery in the urine within 6 hours of administration were 83.6%, 62.9 +/- 23.1%, and 77.3%, respectively. The subjects for whom drug responses were evaluable consisted of 1 case of suppurative meningitis, 8 cases of respiratory tract infection, 2 cases of urinary tract infection, 2 cases of oral infection, 2 cases of pharyngotonsillitis, 1 case of skin soft tissue infection, and 1 case of external otitis, totaling 17 cases. The efficacy rate was 88.2%. The drug proved so effective on suppurative meningitis in particular that the patient was healed without leaving any sequela behind. Seven strains were identified as causative pathogens (5 strains of Haemophilus influenzae, 1 strain of Staphylococcus aureus, 1 strain of group B Streptococcus) isolated from 6 patients. All but 1 strain were eradicated (the rate of eradication 83.3%). In the patients with suppurative meningitis the bacterial count of spinal fluid was markedly decreased 6 hours after drug administration and the organism was eradicated in 45 hours. Eruption was noted in 1 patient as a side effect of CZOP, but disappeared soon after discontinuation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

[Experience of fluconazole granules and injection in pediatric patients].

Fluconazole (FLCZ) is an antifungal agent of triazole class and has been proven to be effective against deep-seated mycosis caused by Candida spp., Aspergillus spp. and Cryptococcus spp. This time, as we had an opportunity to use fluconazole granules, a new dosage form of the agent, we investigated its efficacy and safety in children with deep-seated mycosis together with the efficacy of the injectable form of the agent. FLCZ was administered to 6 patients with fungal infections for treatment and 5 compromised hosts with a high risk of fungal infections for evaluation of its prophylactic effect. The patients enrolled in the study were 11 in total, of whom 6 patients were evaluated for efficacy: fungal phlegmon in 2, esophageal candidiasis in 2, fungal bronchitis in 1 and oral mycosis in 1. Causative fungi for those infections were Candida albicans in 4 patients, Aspergillus, fumigatus in 1 and Aspergillus flavus in 1. The clinical efficacies were excellent in 3 patients and good in 3. The mycological efficacies were rated as eradicated in 5 patients and reduced in 1. In 5 patients to whom FLCZ was given prophylactically, development of neither fungal infection nor unknown fever was noted. No side effects nor clinical laboratory abnormalities were observed during treatment with either granules or injection, indicative of its safety in children.

Administration, Oral↗
PubMed1993

Central administration of senktide, a tachykinin NK-3 agonist, has an antidiuretic action by stimulating AVP release in water-loaded rats.

Intracerebroventricular (i.c.v.) injections of senktide (0.01-10 nmol), a tachykinin NK-3 agonist, had an antidiuretic action in water-loaded rats (4.5% body wt.). Pretreatment with OPC-31260 (1 mg/kg, i.v.), a non-peptide vasopressin V2 antagonist, inhibited the antidiuretic action induced by exogenous arginine vasopressin (AVP, 0.1 micrograms/kg, i.v.) and senktide (0.1 nmol, i.c.v.). In addition, senktide (11.8 nmol, i.c.v.) caused a marked increase of the plasma AVP level in conscious rats. These results suggest that the central NKB analogue senktide has an antidiuretic effect by stimulating AVP secretion from the pituitary gland through the NK-3 receptor in the hypothalamus.

Animals↗
PubMed1993

Mutation-spectrum of a true abasic site in codon 12 of a c-Ha-ras gene in mammalian cells.

An abasic site is postulated to be a premutagenic lesion. We previously reported that a c-Ha-ras gene with an abasic site analogue at either the first or the second position of codon 12 induced the formation of foci by point-mutational activation of the gene [Kamiya et al. (1992) Nucleic Acids Res. 20, 4409-4415]. In this study we constructed c-Ha-ras genes with a true abasic site in codon 12. The ras genes were found to be activated in NIH3T3 cells by a mutation to A at the modified and flanking positions, and the flanking mutations were detected more frequently.

3T3 Cells↗
PubMed1993

Acorn barnacle Megabalanus rosa lectin (BRA-3): cDNA cloning, gene structure and seasonal changes of mRNA and protein levels.

We have isolated cDNA clones coding for a lectin (BRA-3) from the acorn barnacle, Megabalanus rosa. Sequence comparison of the cDNA clones has revealed polymorphism in the BRA-3 mRNA, which results from single-nucleotide (nt) differences at three positions. All three differences are within the coding region and cause conservative amino acid (aa) changes. The BRA-3 gene is composed of four exons, and the three single-nt differences are located on different exons. In addition, the BRA-3 mRNA and BRA-3 protein levels increased during early summer in a similar fashion, indicating that BRA-3 production is regulated mainly at the level of transcription.

Amino Acid Sequence↗
PubMed1993

Receptor-mediated specific biological activity of a beta-amyloid protein fragment for NK-1 substance P receptors.

A beta-amyloid protein fragment AP21-35 (tetradeapeptide with amino acid residues 21-35) was found to be a highly selective agonist of substance P receptors (NK-1) among three tachykinin receptor subtypes. This peptide fragment contracted the smooth muscle preparations of guinea pig ileum in a dose dependent manner (EC50 = 22 microM). This activity was completely reversed by CP-96,345-1, a specific antagonist of NK-1 receptors, whereas atropine for NK-3 had no effect. The peptide was inactive in rat vas deferens which contains predominantly NK-2 receptors. These results indicated that AP21-35 is a highly selective agonist for NK-1 receptors. In the radio-ligand receptor binding assay using [125I]-Bolton-Hunter substance P to membranes from guinea pig ileum, the fragment exhibited a distinct dose-response curve (IC50 = 11 microM). All the present data strongly suggest that beta-amyloid protein function as a peptide ligand of substance P receptors with some pathophysiologic activities.

Amino Acid Sequence↗
PubMed1993

Cyclobutane thymine dimers in a ras proto-oncogene hot spot activate the gene by point mutation.

ras proto-oncogenes with a cyclobutane-type thymine photodimer (cis-syn or trans-syn isomer) were constructed by replacement of a portion of the gene with a chemically synthesized fragment. When the genes were transfected by the calcium phosphate method into mouse NIH3T3 cells, they induced focus-formation, indicating that both photoproducts were mutagenic in mammalian cells. Sequence analysis of the ras gene fragments derived from the transformed cells showed that the genes were activated by a point mutation. The mutations detected most frequently were 3'-T-->A for the cis-syn isomer and 5'-T-->A for the trans-syn isomer. In contrast, a different trend of mutations was observed when a primer on a DNA template with a cis-syn dimer was extended in vitro by either DNA polymerase beta or alpha.

3T3 Cells↗
PubMed1993

Ten-year survey of the intellectual deficits in children with acute lymphoblastic leukemia receiving chemoimmunotherapy.

Effects of chemoimmunotherapy, including cranial irradiation for central nervous system (CNS)-directed therapy, on children with acute lymphoblastic leukemia (ALL) were investigated. Fifty-five children with ALL in continuous complete remission (> 5 yr) and without evidence of current or past CNS diseases were evaluated in this retrospective study. Using standard measures of intelligence (IQ), we repeatedly (1-4 times/person; mean 2.1 times) evaluated IQ in the cohort of patients for the mean follow-up time of 9.7 yr, ranging from 5.4 to 15.8 yr. Fifty-five patients received the total number of 118 IQ testings and 40 patients received them more than twice. Patients were examined periodically at intervals of 1.4 to 10.0 yr (mean 4.8 yr) following diagnosis. Most of the published studies dealt with single IQ testing, and long-term follow-ups were not enough to assess the consequent IQ change. This report confirms and extends the previous findings: decreased IQ was related to age at diagnosis and irradiation (< 5 yr of age at diagnosis), irradiation-examination interval, and female sex. Further long-term follow-up study will be needed in these groups, since their IQs are still on the decline even after 10 yr of diagnosis.

Adolescent↗
PubMed1993

Long-lasting potentiation of synaptic transmission in the Schaffer collateral-commissural pathway of the guinea pig hippocampus by activation of postsynaptic N-methyl-D-aspartate receptor.

The effects of short-period (2 min) perfusion of conditioning solution, which contains N-methyl-D-aspartate (NMDA), glycine, and spermine, on the synaptic transmission in the Schaffer collateral-commissural pathway were examined in hippocampal slices with the intracellular recording technique. Long-lasting potentiation of excitatory postsynaptic potentials (EPSPs) was induced (as long as the records lasted, up to 3 h in the longest observation) after membrane potentials of postsynaptic neurons were depolarized by current injection during perfusion of the conditioning solution. D-2-amino-5-phosphonovaleric acid (D-AP5), a specific antagonist of NMDA receptors, block the induction of the long-lasting potentiation by perfusion of NMDA containing solution. This potentiation was accompanied by a decrease in the relative magnitude of EPSP amplitude fluctuation (coefficient of variation, CV). The reciprocals of squared CVs (= mean2/variance) were almost proportional to the magnitude of the potentiation, and the ratios of 1/CV2 and the magnitudes of potentiation were not different from those of long-term potentiation (LTP) induced by tetanic stimulation. These findings suggest that long-lasting potentiation is induced solely by activation of postsynaptic NMDA receptors, and transmitter release from presynaptic terminals may be modified by the activation of postsynaptic receptors.

2-Amino-5-phosphonovalerate↗
PubMed1993

Increase of interleukin 2 receptor and CD45RO antigen on lymphocytes cultured with human cytomegalovirus.

To determine the expression of interleukin 2 receptor (IL-2R) and the change of CD45RA and CD45RO antigen on lymphocytes in response to human cytomegalovirus (HCMV), peripheral blood mononuclear cells (PBMC) were cultured with HCMV antigen, and the expression of IL-2R and of CD45RA and CD45RO antigens on lymphocytes was analyzed by flow cytometry. The expression of IL-2R alpha (p55) and -beta (p75) was significantly increased on T cells obtained from CMV-seropositive donors following culture with the CMV antigen. An increased expression of IL-2R alpha and -beta was observed on both CD4+ and CD8+ cells, but the percentage of cells that expressed IL-2R was higher in CD4+ cells. The percentage of CD45RA+ cells was decreased and the percentage of CD45RO+ cells, especially of CD4+CD45RO+ cells, was increased when cultured with the CMV antigen. These observations suggest that switching of CD45RA+ cells to CD45RO+ cells occurred following stimulation with the CMV antigen. The expression of IL-2R and the activation of memory T cells are important to the recovery from and the protection against CMV infection.

Adult↗
PubMed1993

Immunizing potential of ultraviolet-attenuated cercariae of Schistosoma mansoni in rodent hosts.

Schistosoma mansoni cercariae attenuated with ultraviolet (UV) irradiation (254 nm) at a dose of 18 mJ/cm2 induced partial resistance against a homologous challenge in male ICR mice and male Hartley guinea pigs. The reduction in the adult worm burden was 51% and 37% +/- 13%, respectively. On the other hand, male and female Mongolian gerbils (Meriones unguiculatus) vaccinated with UV-attenuated cercariae exhibited marginal resistance (13% +/- 9% and 22% +/- 10%, respectively). This raises the possibility that gerbils might have an unknown immune-characteristic nature. The usefulness of UV-attenuated cercariae is discussed with respect to the control of the disease.

Animals↗
PubMed1993

Characterization of peptides in sea anemone venom collected by a novel procedure.

Peptide neurotoxins were isolated from the venom obtained by electrical stimulation of the sea anemone Bunodosoma caissarum. This technique allows almost pure venom to be collected, and the animals to survive. Three neurotoxins (assayed on crustacean nerves) were isolated by gel filtration and reversed-phase high performance liquid chromatography. Hemolysins were also detected in the venom. The amino acid sequence of a major neurotoxin BcIII was determined. BcIII has 48 amino acid residues with six half-cystine residues. This sequence has homology with the type 1 long sea anemone neurotoxins. Two minor toxins (BcI and II) have similar amino acid composition and amino-terminal sequences to BcIII.

Action Potentials↗
PubMed1993

Inhibition of varicella-zoster virus (VZV) glycoprotein expression by a human monoclonal antibody against VZV glycoprotein III.

Effects of human monoclonal antibodies (MAbs) against varicella-zoster virus (VZV) glycoproteins (gp) on VZV glycoprotein expression were analyzed by flow cytometry. Human embryonic fibroblast (HEF) cells were inoculated with cell-free VZV and cultured in the presence of human MAbs. While human MAbs directed against gpI (V2) and -II (V1) did not affect VZV expression, a human MAb against gpIII (V3) inhibited expression of VZV gpI, -II, -III, and -IV. V3 also inhibited spread of VZV from infected to uninfected cells. Interferon-alpha, -beta, and -gamma and tumor necrosis factor-alpha were able to synergize with V3 and inhibit VZV gp expression. These results suggest that human MAb V3 may be useful for passive prophylaxis against VZV infection and for treatment of severe VZV infection.

Antibodies, Monoclonal↗