Search PubMed⌕ Search

Biomedical subjects

C Sato

Publications and source records attributed to C Sato.

At least 253 records · Page 14Linked to original sources
PubMed1992

Identification of human blood in mosquitoes (Diptera: Culicidae) using nonradioactive DNA dot blot hybridization.

A dot blot hybridization procedure was developed to detect human blood meals in engorged mosquitoes. A biotinylated DNA probe allowed the detection of 10-100 ng of human DNA, discriminated well between human and nonhuman sources of blood, and cross-reacted only with monkey DNA. Results showed that this method was a specific and sensitive technique for the identification of blood meals up to 100 h after ingestion. The nonisotopic label offers easy handling without the problems inherent in the use of radioisotopes, and it can be adapted for use in routine field tests.

Animals↗
PubMed1992

Stimulation of keratinocyte migration by growth factors.

Migration of keratinocytes from the wound edge is thought to be one of the critical features of reepithelialization. A quantitative migration assay was carried out using normal human keratinocytes. Keratinocytes, seeded on 12 well plates, were grown in serum free, keratinocyte growth medium (KGM, Curabo Co) with 0.08 mM Ca2+. The medium was switched from KGM to keratinocyte basal medium (KBM) 6 h prior to the wounding. Half of the plate's confluent monolayer of keratinocytes was removed with razor blade, and the remaining keratinocytes were incubated in KBM for 16 hrs in the presence of indicated growth factors. After incubation, the cells were fixed and counted at 100 magnification. Migration was quantitated by counting the number of cells in ten successive 125-microns zones. Transforming growth factor alpha (TGF-alpha), acidic and basic fibroblast growth factor (aFGF, bFGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), and insulin-like growth factor-I (IGF-I) stimulated the migration of keratinocytes, while TGF-beta suppressed it.

Cell Movement↗
PubMed1992

[Effects of adrenergic drugs injected into the nucleus tractus solitarius region on the baroreceptor reflex in rabbits].

It has been presumed that a primary site of termination of the baroreceptor afferent was in the nucleus tractus solitarii (NTS). The intermediate region of the nucleus, located at the level of the obex, contains a large number of catecholamine neurons. The principal noradrenergic innervation of the NTS appears to arise from neurons of the so-called A2 group. It has been proposed that catecholamines released by A2 neurons serve to lower blood pressure and heart rate. We performed experiments to determine the effects of alpha-adrenoceptor agonists and antagonists on the baroreceptor reflex and alpha-adrenoceptor. Rabbits anesthetized with chloralose-urethane were injected with an alpha-adrenoceptor agonist, such as noradrenaline, phenylephrine or clonidine, into the NTS. An adrenoceptor-antagonist, such as yohimbine, phentolamine, prazosin or corynanthine was injected into the NTS of other anesthetized rabbits. Clonidine markedly lowered the blood pressure and heart rate, and it inhibited the baroreceptor reflex responses. Noradrenaline or phenylephrine did not lower the blood pressure and heart rate and scarcely inhibited the baroreceptor reflex. Yohimbine remarkedly inhibited the baroreceptor reflex responses; on the other hand, prazosin, corynanthine and phentolamine produced little inhibition of the responses. It is concluded that there are alpha 1- and alpha 2-receptors in the NTS of the rabbits, and the alpha 2-receptors play an important role in the neurotransmission in the NTS.

Animals↗
PubMed1992

Effects of caffeine on paracetamol activation in rat and mouse liver microsomes.

1. The effects of caffeine on the NADPH-dependent production of paracetamol-glutathione conjugate were studied in rat and mouse liver microsomes. 2. In the presence of caffeine, glutathione conjugate production in rat microsomes was enhanced, whereas that in mouse microsomes was not affected significantly, showing an apparent species difference. 3. The data partly explain the species difference in the effects of caffeine on paracetamol hepatotoxicity.

Acetaminophen↗
PubMed1991

Hyperreactivity of alpha 1-adrenoceptors, but not of P2X-purinoceptors, in vas deferens of spontaneously hypertensive rats.

We evaluated the contractile reactivity to various stimuli, and the content and release of noradrenaline (NA) from a non-vascular tissue, the vas deferens, isolated from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). The concentration-contraction curves for NA in tissue from animals of two ages (10-25 weeks and 30-45 weeks) were shifted to the left in SHR as compared with in age-matched WKY, with significant differences at 1.0 and/or 10 microM of NA. Similarly, the amplitude of contraction produced by electrical stimulation at 4, 8 and 16 Hz in the tissue was much larger in SHR than in WKY. However, ATP (10-100 microM) evoked contractions of the tissue to a similar extent in both SHR and WKY. The electrically evoked contractions of vas deferens from both strains were inhibited by isoprenaline in an approximate dose-dependent and equipotent manner. The tissue NA content, determined by HPLC-ECD, was nearly same in both SHR and WKY. In addition, the same amount of NA was released from the vas deferens of both strains by electrical stimulation in the presence of 4-aminopyridine. The present findings indicate that the contractile response of vas deferens to stimulation of alpha 1-adrenoceptors, but not of beta-adrenoceptors or P2X-purinoceptors, is more pronounced in SHR than in WKY and that a response indicative of hypertension may also occur in non-vascular tissue as it does in vascular tissue.

Adenosine Triphosphate↗
PubMed1991

Phenotypic modulation in lipocytes in experimental liver fibrosis.

The presence of a-smooth muscle actin (smA)-positive cells has recently been reported in the fibrotic liver. Lipocytes have been considered to play important roles in hepatic fibrosis. However, the relation of the a-smA-positive cells and lipocytes has not been determined. The biological implication of a-smA expression remains unknown. To study these questions, we carried out double immunofluorescent staining of a-smA and desmin (a marker for lipocytes), or a-smA and collagen, and double immunohistochemical staining of a-smA and 5-bromo-2'-deoxyuridine (BrdUrd) in carbon tetrachloride-induced fibrotic rat livers. In normal and control livers, a-smA-positive cells were not seen in the lobules, whereas scattered desmin-positive cells were present. With the development of hepatic fibrosis, a-smA was expressed only in a portion of desmin-positive cells located predominantly around collagen bundles. A number of a-smA-positive cells in the lobules were labelled with BrdUrd. These results suggest phenotypic modulation in lipocytes and differentiation of lipocytes towards myofibroblast-like cells, since a-smA is expressed with desmin in myofibroblasts in scar tissue. The expression of a-smA may be related to events of the fibrotic process, such as tissue contraction or fibrogenesis per se.

Actins↗
PubMed1991

Somatosensory evoked potentials following stimulation of median and tibial nerves in patients with localized intracerebral hemorrhage: correlations with clinical and CT findings.

Median and tibial somatosensory evoked potentials (SEPs) were performed on 38 patients with localized intracerebral hemorrhage, 23 with thalamic hemorrhage and 15 with putaminal hemorrhage. Of 65 arms and 62 legs examined, cerebral evoked responses of 60 arms and 50 legs were diagnosed as abnormal. The abnormal findings in scalp-recorded SEPs consisted of a reduction in amplitude, loss of waves and delay in peak latencies. The SEP abnormalities were not indicative of location of hemorrhage. Absence of SEPs was more frequently observed in large hemorrhages and at the early stage. Substantial improvement in SEPs was observed over several months after stroke in many limbs. Motor function as evaluated with Brunnstrom staging of the upper limbs whose SEPs were absent was lower than that whose SEPs were evoked, but that was not observed in the lower limbs because in some cases absence of SEPs coexisted with good motor function. Loss of SEP waves had a significant correlation with disturbed deep sensation. The median and tibial SEPs provided an excellent clinical correlation with the patients' improvement over several months.

Adult↗
PubMed1991

Synergistic effect of NADH on NADPH-dependent acetaminophen activation in liver microsomes and its inhibition by cyanide.

The effects of NADH and cyanide on NADPH-dependent acetaminophen activation in rat and mouse liver microsomes were studied. In both rat and mouse microsomes, NADPH-dependent acetaminophen-glutathione conjugate production was synergistically enhanced by the addition of NADH, whereas NADH alone did not initiate this reaction. The data suggest that the second electron in this reaction may be transferred from NADH. The present findings are different from a previous report in a reconstituted system that NADH decreases covalent binding of acetaminophen to proteins. This reaction was inhibited by low concentrations of sodium cyanide. The role of the cyanide sensitive factor in this reaction in liver microsomes remains to be further clarified.

Acetaminophen↗
PubMed1991

Inhibition of acetaminophen activation by ethanol and acetaldehyde in liver microsomes.

Mechanisms of the inhibitory effect of ethanol on acetaminophen hepatotoxicity are controversial. We studied the effects of ethanol and acetaldehyde, an oxidative metabolite of ethanol, on NADPH-dependent acetaminophen-glutathione conjugate production in liver microsomes. Ethanol at concentrations as low as 2mM prevented the conjugate production noncompetitively. Acetaldehyde also inhibited acetaminophen-glutathione conjugate production at concentrations as low as 0.1mM that is comparable with those observed in vivo after social drinking. Acetaldehyde may be involved in ethanol-induced inhibition of acetaminophen hepatotoxicity.

Acetaldehyde↗
PubMed1991

Characterization of the acetaminophen-glutathione conjugation reaction by liver microsomes: species difference in the effects of acetone.

NADPH-dependent production of acetaminophen-glutathione conjugate has been partly characterized in rat liver microsomes. The reaction showed the characteristics of mixed function oxidase when glutathione concentration was higher than 0.2 mM. It is suggested that hydroxy radical and superoxide are not involved in this reaction. When the reaction was compared among rat, mouse and rabbit microsomes, mouse microsomes showed the highest activity; this was almost 4 times higher than the others, which may, at least in part, explain the susceptibility of mouse to acetaminophen-induced hepatotoxicity. There was also a species difference in the effects of acetone; this was enhanced in the rat microsomes, inhibited in the mouse, and minimally affected in the rabbit.

Acetaminophen↗
PubMed1991

Appearance of alpha-smooth-muscle-actin-positive cells in hepatic fibrosis.

The appearance of alpha-smooth-muscle-actin (alpha-smA)-positive cells during hepatic fibrosis was studied immunohistochemically in rat and human livers. In the normal rat liver, alpha-smA was observed only in vascular smooth muscle cells. With the progression of fibrosis induced by CCl4 injection, alpha-smA-positive cells appeared in the perisinusoidal space and the fibrous septa, and ultimately surrounded regenerative nodules. An increase of desmin-positive cells was recognized in the fibrotic areas and the perisinusoidal area. In the human liver, alpha-smA-positive cells appeared in the fibrotic area, whereas no desmin-positive cells were observed, except in vascular walls of the central vein and the portal tract, alpha-smA is a good marker for the detection of myofibroblast-like cells, and the appearance of alpha-smA in liver mesenchymal cells seems closely related to the process of hepatic fibrosis in both rat and man.

Actins↗
PubMed1991

Existence of ATP-evoked ATP release system in smooth muscles.

Effects of stable ATP analogs such as alpha,beta-methylene ATP (alpha,beta-mATP) and beta,gamma-methylene ATP (beta,gamma-mATP) on ATP release and contractile response were evaluated in the vas deferens and ileal longitudinal muscles of guinea pig. In these smooth muscles, administration of alpha,beta-mATP (10, 30 or 100 microM) produced an ATP release accompanied by a transient contraction, but alpha,beta-methylene ADP (30 or 100 microM) or adenosine (30 microM) failed to elicit both the ATP release and the contraction. However, the peak responses of ATP release and contraction to alpha,beta-mATP (100 microM) in the vas deferens appeared around 2 min and 2.62 sec, respectively, after the injection of the drug. Beta,gamma-mATP (10 or 100 microM) caused an ATP release from the vas deferens. The ATP release as well as the contraction evoked by alpha,beta-mATP or beta,gamma-mATP were effectively inhibited by 300 microM suramin, a P2 purinoceptor antagonist. By contrast, ATP release and contractile response to norepinephrine in the vas deferens and those to bethanechol in the ileum were virtually unaffected by this antagonist. Veratridine and ouabain at (30 or 100 microM) caused markedly acetylcholine release from the ileum and norepinephrine release from the vas deferens, respectively. However, alpha,beta-mATP, even in a high concentration of 100 microM, did not elicit any release of acetylcholine or norepinephrine. These findings suggest that alpha,beta-mATP and probably beta,gamma-mATP evoke ATP release from not neuronal but mainly smooth muscular sites by activating suramin-sensitive P2x receptors, implying that "ATP-evoked ATP release system" exists.

Acetylcholine↗
PubMed1991

Statistical analysis of the ability of police dental surgeons in identification of dental filling materials.

The subjects, 77 police dental surgeons at 50 police stations in Kanagawa prefecture, were asked to identify either gold foil filling, gold inlay, palladium alloy inlay, silver alloy inlay, which had been filled in 5 human skulls. We conducted a statistical analysis of the dispersion of agreement rates in identifying the filling materials according to their clinical career. The results showed that the rates for gold inlay and gold foil filling were higher than those for silver alloy inlay and palladium alloy inlay. However, it was concluded that caution is necessary in identifying elaborately-finished fresh filling materials.

Adult↗
PubMed1991

Nucleotide sequence of a gene encoding a new genus specific protein of Chlamydia psittaci.

DNA fragment No. 13 from the C. psittaci pigeon strain, has been cloned in the plasmid pUC19. Hybridization analysis revealed that the fragment maintained a chlamydial common sequence. Furthermore, nucleotide sequencing identified two partial open reading frames (ORF), 675b. p. and 530b. p. Expression of ORFs revealed that the second ORF encoded 25KD polypeptide, whereas the first ORF did not produce any antigenic product. The 25KD beta-galactosidase fusion protein reacted strongly with chlamydia-specific antibodies elicited against a number of different chlamydial strains. Gene Bank analysis showed that this cloned gene is not highly homologous with chlamydia or other organisms for which nucleotide sequences have already been published. This 25KD polypeptide may be an additional genus-specific antigen of Chlamydiae.

Amino Acid Sequence↗
PubMed1991

Characterization of DNA fragment from Chlamydia psittaci avian strain which shows high homology with hypB gene of Chlamydia.

A study was performed to characterize DNA fragment No. 17 of C. psittaci strain P-1041 which encoded 42 KD beta-galactosidase fusion protein with type-specific antigenicity. Sequence determination identified a partial open reading frame that spanned about 1,200b. p. nucleotides. Screening the literatures for the nucleotide and deduced amino acid sequences revealed extensive similarity between the DNA fragment of P-1041 and two chlamydial hypB genes. This DNA showed 91.5% homology with C. psittaci GPIC hypB gene in nucleotide sequence and 96.4% homology in deduced amino acid sequence. The hypB gene of C. trachomatis serovar A and the P-1041 DNA fragment showed 81.2% and 91.3% homology in nucleotide and amino acid sequences, respectively. Dot enzyme-linked immunosorbent assay, for the products of deleted DNA fragments defined the coding region for type-specific antigenic polypeptide. In addition, the P-1041 DNA fragment carried a sequence highly homologous (greater than 49%) with other bacterial and plant genes called chaperonin which responds to various stress in cells. From these results, the P-1041 DNA fragment was found to be a part of hypB gene and to encode the region critical for type-specific antigenicity.

Amino Acid Sequence↗
PubMed1990

Phosphorylation sites linked to glial filament disassembly in vitro locate in a non-alpha-helical head domain.

Glial fibrillary acidic protein (GFAP), the intermediate filament component of astroglial cells, can serve as an excellent substrate for both cAMP-dependent protein kinase and protein kinase C, in vitro. GFAP phosphorylated by each protein kinase does not polymerize, and the filaments that do polymerize tend to depolymerize after phosphorylation. Dephosphorylation of phospho-GFAP by phosphatase led to a recovery of the polymerization competence of GFAP. Most of the phosphorylation sites for cAMP-dependent protein kinase and protein kinase C on GFAP are the same, Ser-8, Ser-13, and Ser-34. cAMP-dependent protein kinase has one additional phosphorylation site, Thr-7. All the sites are located within the amino-terminal non-alpha-helical head domain of GFAP. These observations pave the way for in vivo studies on organization of glial filaments.

Animals↗