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Biomedical subjects

H Kamiya

Publications and source records attributed to H Kamiya.

At least 343 records · Page 19Linked to original sources
PubMed1990

Survey of enteropathogenic agents in children with and without diarrhoea in Ghana.

A survey was carried out over 1 year in a rural area of Ghana on the isolation, detection and/or identification of enteric pathogens from children under 5 years of age with and without diarrhoea. The isolation and detection rate of Shigella flexneri, Shigella dysenteriae, Giardia lamblia and Rotavirus were higher in children with diarrhoea than in controls. Yersinia enterocolitica, Vibrio cholerae and Vibrio parahaemolyticus were not isolated during the period of this survey. The incidence of other enteropathogenic bacteria and parasites identified in the diarrhoeal and non-diarrhoeal children was calculated and is discussed in this study.

Age Factors↗
PubMed1990

[Pharmacokinetics and clinical studies on aztreonam in neonates].

Pharmacokinetic and clinical studies on aztreonam (AZT) were performed in neonates. Serum concentrations and urinary excretion of AZT were determined in 12 neonates with ages between 0 and 7 days (birth weights were between 1,260 and 3,500 g) upon intravenous injection or 1 hour drip intravenous infusion of AZT at 20 mg/kg. Serum concentrations of AZT at 1 hour after i.v. administration were 54.0 +/- 12.5 micrograms/ml, and half-lives were 6.01 +/- 0.70 hours. Serum concentrations of AZT reached their peaks at the end of drip infusion with levels of 42.1 +/- 17.6 micrograms/ml in the d.i.v. group and half-lives were 6.40 +/- 1.88 hours. Urinary recovery rates in the first 12 hours after administration were 28.5 +/- 6.4% for the i.v. group and 32.3 +/- 13.9% for the d.i.v. group. AZT was administered to 12 neonatal patients (2 cases of sepsis, 2 cases of suspected sepsis, 3 cases of pneumonia, 2 cases of urinary tract infection and 3 cases for prophylaxis), and clinical effectiveness, bacteriological efficacy and adverse reactions were evaluated. Clinical efficacies in 9 cases except 3 cases with prophylactic use were excellent in 1 case, good in 5 cases, fair in 1 case, poor in 1 case and unknown in 1 case, thus the efficacy rate was 75%. Bacteriological effects in 3 strains with Gram-negative bacilli were eradicated in 2 strains and unchanged in 1 strain, hence the bacteriological eradication rate was 66.7%. Increased GOT and GPT were observed in 1 cases as abnormal laboratory test results, but the abnormality was not serious.(ABSTRACT TRUNCATED AT 250 WORDS)

Aztreonam↗
PubMed1990

[Clinical evaluation of norfloxacin in children].

We administered norfloxacin (NFLX) to 16 children aged 3 to 14 year-old at the dose of 5.2 to 17.2 mg/kg/day. We evaluated the efficacy and safety of NFLX in 6 children with respiratory tract infections, 8 urinary tract infections, and 2 gastrointestinal tract infections. Efficacy rate of NFLX was 93.8% and eradicated rate was 92.9%. Any adverse effects were not observed. These results suggested that NFLX could be used safely to the children.

Adolescent↗
PubMed1990

[A case of mitral valve prolapse associated with unusual posterior wall motion of the left ventricle: where has the myocardial theory gone?].

A case with mitral valve prolapse was reported in which unusual movement of the posterior left ventricular wall was observed. The patient was a 45-year-old woman. Physical examination revealed loud multiple clicks at the apex. An electrocardiogram revealed T wave inversion in leads 2, 3 and aVF. Two-dimensional and M-mode echocardiography disclosed mid-systolic buckling of the mitral valve and late systolic 'dip' in the posterior wall of the left ventricle. An exaggerated excursion of the posterior wall during early diastole was also recorded by M-mode echocardiography. Pulsed and M-mode color Doppler echocardiography detected unusual anterograde flow near the mitral valve. This flow coincided well in timing with the early diastolic exaggerated excursion of the posterior wall. A discussion was made on the relation between abnormal left ventricular wall motion and mitral valve prolapse.

Echocardiography, Doppler↗
PubMed1989

Central pressor actions of neurokinin B: increases in neurokinin B contents in discrete nuclei in spontaneously hypertensive rats.

The regional distributions of neurokinin B-like immunoreactivity and substance P-like immunoreactivity in the central nervous system in spontaneously hypertensive rats (SHRs) and normotensive Wistar Kyoto rats (WKYs) were examined. The distribution of neurokinin B-like immunoreactivity in WKYs was not exactly the same as that of substance P-like immunoreactivity. The neurokinin B-like immunoreactivity contents of the supraoptic nucleus of the hypothalamus and the caudal part of the nucleus tractus solitarii were higher in SHRs than in WKYs. Injections of selective neurokinin B receptor peptides, senktide (suc-[Asp6,Me-Phe8]-substance P6-11) and [Pro7]-neurokinin B, into the lateral brain ventricle of the normotensive rats caused dose-dependent increases in the blood pressure, and blockade of peripheral vascular vasopressin receptors reduced these pressor responses, but did not affect the substance P-induced pressor response. These findings suggest that the novel tachykinin peptide, neurokinin B has an important role in central pressor action in rats.

Animals↗
PubMed1989

Synthesis of a gene for the protein kinase domain of the epidermal growth factor receptor and its expression in Escherichia coli.

A gene encoding the protein kinase domain of the epidermal growth factor receptor has been chemically synthesised, cloned and expressed in Escherichia coli. The 942-base-pair gene was constructed by enzymatic ligation of 56 oligonucleotides and cloned into an expression vector downstream of the E. coli trp promoter. Production of active gene product was confirmed by means of a protein kinase assay, demonstrating that the enzymatic activity of the protein kinase domain of the epidermal growth factor receptor is retained after expression in E. coli.

Amino Acid Sequence↗
PubMed1989

Design of RNA enzymes distinguishing a single base mutation in RNA.

RNA enzymes (ribozymes) which can cleave RNA by recognizing sequences of 9-15 bases are described. Substrates must contain UX (X = U, C or A). A ribozyme consisting of two oligoribonucleotides (19 mer and 15 mer) was shown to cleave a ribo 11 mer catalytically with Km and kcat values of 0.53 microM and 0.03 min-1, respectively. A non-cleavable substrate-ribozyme complex containing 2'-O-methylnucleoside was prepared and CD spectra were compared at different temperature. In order to obtain an efficient ribozyme, a one-strand RNA with a chain length of 37 was prepared. The ribozyme was shown to distinguish a single base mutation in mRNA's which were prepared by transcription of two synthetic DNA duplexes coding for positions 7-26 of c-Ha-ras protein. The mutant (Val-12) mRNA which had GUU was cleaved but the wild type mRNA which contained GGU was not changed, when treated by the ribozymes in the presence of Mg2+.

Base Sequence↗
PubMed1989

Simultaneous recording of presynaptic spikes and excitatory postsynaptic potentials from monosynaptically connected hippocampal neurons.

A technique has been devised to activate single granule cells in the hippocampus, and to record simultaneously spikes from the particular granule cell and excitatory postsynaptic potentials from a monosynaptically connected CA3 neuron. The unitary excitatory postsynaptic potentials (EPSPs) sustained for long observation periods, and increased in size with increases in stimulus frequency and in external Ca2+ concentration. This technique may be useful for quantal analysis of transmission through the synapse between mossy fibers and CA3 neurons.

Action Potentials↗
PubMed1989

Isolation and characterization of a novel cytolytic factor in purple fluid of the sea hare, Aplysia kurodai.

A novel cytolytic factor, aplysianin P, which induces tumor lysis, was purified to apparent homogeneity from the purple fluid of the sea hare Aplysia kurodai. Purified aplysianin P was a single Mr 60,000 polypeptide. This factor was half-maximally active at 3-25 ng protein/ml and lysed all the tumor cells tested but did not lyse normal WBC or RBC. Aplysianin P was labile on treatments with heat, low pH, urea, and periodate, but not with Pronase. The factor completely inhibited the syntheses of DNA, RNA, and protein by tumor cells within 2 h and caused their complete cytolysis within 18 h. Tumor lysis by aplysianin P was inhibited by N-acetylneuraminic acid, suggesting that recognition of the sugar moiety is a key step in the cytolysis induced by aplysianin P. The factor also prolonged the survival of mice bearing syngeneic MM46 ascites. It did not resemble previously isolated antineoplastic glycoproteins from the eggs (aplysianin E) or albumen gland (aplysianin A) of A. kurodai in terms of molecular size, antigenicity, or amino acid composition. These results suggest that aplysianin P found in an invertebrate, the sea hare, is a new antitumor factor.

Amino Acids↗
PubMed1989

Cardiovascular roles of tachykinin peptides in the nucleus tractus solitarii of rats.

Unilateral removal of the afferent fibers of the IXth and Xth cranial nerve (nodose ganglionectomy) caused significant decrease in the content of substance P-like immunoreactivity (SP-LI) and neurokinin A-like immunoreactivity (NKA-LI) in the nucleus tractus solitarii (NTS) of rats. Microinjection of SP (1 ng) or NKA (10-100 ng) into the NTS caused prompt, transient hypotension and bradycardia, suggesting that SP and NKA may be neurotransmitters of the baroreceptor reflex in the NTS. NKB-like immunoreactivity (NKB-LI) was also detected in the NTS of rats by radioimmunoassay, but its content in the NTS was not affected by unilateral nodose ganglionectomy. The microinjection of 1-10 ng of suc-[Asp5, Me-Phe8]-SP(6-11) (senktide, a selective neurokinin B receptor peptide) into the NTS caused long-lasting hypertension and tachycardia. These results indicate that NKB may also be a neuromodulator on cardiovascular responses in the NTS.

Animals↗
PubMed1989

Direct projections from Ammon's horn to the rostral raphe regions in the brainstem of the cat.

When WGA-HRP (wheat germ agglutinin-horseradish peroxidase conjugate) or HRP was injected into the regions around the superior central and/or the dorsal raphe nuclei in the cat, cell bodies of a number of non-pyramidal neurons were labeled in Ammon's horn. Thus the existence of direct projections from non-pyramidal neurons in Ammon's horn to the rostral raphe regions in the brainstem was suggested in the cat.

Animals↗
PubMed1989

Synergistic interaction between etoposide and 1-beta-D-arabinofuranosylcytosine.

The sequence-dependency of the antitumor effect of etoposide (VP-16) and 1-beta-D-arabinofuranosylcytosine (ara-C) and its mechanisms were investigated in L1210 ascites tumor. Treatment with VP-16 (15 mg/kg) and ara-C (25 mg/kg) was administered intraperitoneally on days 1, 4, and 7 after tumor inoculation. Three-hour pretreatment with VP-16 followed by ara-C produced 70% of cure rate, but only 20% of cure rate was obtained with the reverse sequence. Simultaneous administration led to the worst therapeutic result. To clarify this sequence-dependent interaction of the both drugs, the effect of VP-16 on incorporation of ara-C into DNA was investigated in vivo. On day 3 after intraperitoneal transplantation of 1 x 10(6) L1210 cells, 15 mg/kg of VP-16 and 1 microCi of (3H)ara-C was administered intraperitoneally with or without time interval. The effect of VP-16 on ara-C incorporation was also strikingly schedule-dependent and compatible with the schedule dependency of the antitumor effect. At 1 hr after injection of ara-C, simultaneous administration of 15 mg/kg of VP-16 reduced ara-C incorporation by 67% of ara-C injection alone. But in sharp contrast to simultaneous-administration, 3 hour preadministration of VP-16 increased ara-C incorporation up to 247%. From 1 to 6 hour after intraperitoneal administration of 15 mg/kg of VP-16, the sedimentation rate of L1210 DNA was increasing on alkaline sucrose gradients. This repairing period from VP-16 induced DNA damage might be the vulnerable time to ara-C through an increase in ara-C incorporation into DNA.

Animals↗
PubMed1989

Discontinuing therapy in childhood acute lymphoblastic leukemia treated with a chemoimmunotherapy protocol.

We examined the results of discontinuing therapy in Japanese children with acute lymphoblastic leukemia. Of the 209 patients in the chemoimmunotherapy study, 120 (57.4%) had all chemotherapy stopped after 3 years of complete remission, and 72 (34.4%) reached the point of discontinuing immunotherapy after 5 years of complete remission. Of the 120 children removed from chemotherapy, 14 (11.7%) have relapsed, mainly in the extramedullary sites (5: testis, 5: bone marrow, 3: central nervous system, 1: bone); relapses occurred 1-23 months after cessation of chemotherapy (median 11 months). Boys had higher post-chemotherapy relapse rate than girls (0.21 versus 0.08, P less than 0.05). None of the 72 children removed from immunotherapy have yet relapsed. Long-term remission and possibly cure can be expected in approximately one-half of newly diagnosed Japanese patients. Although the active immunotherapy had no beneficial effect on the overall outcome for leukemic children, it could be of benefit to the elimination of bone marrow relapses after cessation of chemotherapy.

Antineoplastic Agents↗
PubMed1989

Purification and characterization of an antibacterial and antineoplastic protein secretion of a sea hare, Aplysia juliana.

The fetid secretion of a sea hare, Aplysia juliana, was lethal to crabs and also inhibited the growth of bacteria. When the secretion was partitioned between water and n-hexane, only the n-hexane layer, which had a nauseating odor, was lethal to crabs. The water-soluble fraction showed strong antibacterial activity and inhibited the growth of both Gram-positive and Gram-negative bacteria. Antibacterial activity of the water-soluble fraction was destroyed by heating at 50 degrees C for 15 min, but was resistant to treatment with proteolytic enzymes. The active principle, named julianin-S, was purified by gel filtration and ion exchange chromatography. The purified specimen gave a single protein showing a mol. wt of approximately 67,000, as determined by gel filtration. Julianin-S inhibited the growth of Bacillus subtilis by 50% at a concentration of 70 ng protein/ml. It was also cytotoxic to murine tumor cells and inhibited in vitro growth of L1210 cells by 50% at a concentration of 8 ng protein/ml.

Animals↗