Improvement of post-reperfusional energy status by supplement of lipid emulsion in liver transplantation.
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Animals↗
Biomedical subjects
T Yagi
Publications and source records attributed to T Yagi.
Can intraoperative inoculation of donor splenocytes via the portal vein prolong allograft survival?
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Animals↗
Ca2+ regulation by the Na(+)-Ca2+ exchanger in retinal horizontal cells depolarized by L-glutamate.
This study is concerned with regulation of the intracellular Ca2+ concentration ([Ca2+]i) of horizontal cells isolated from cyprinid fish retinae, with the main emphasis on the role of the (Na+)-Ca2+ exchanger. An inward current was blocked by Ca2+ (4 mM) during prolonged (> 1 h) depolarization by L-glutamate (100 microM) in the whole-cell voltage-clamp configuration, suggesting the persistent activation of voltage-gated Ca2+ channels. This (Co2+)-sensitive current was absent when extracellular Na+ was replaced by Li+ to suppress (Na+)-Ca2+ exchange. Measurement of [Ca2+]i using the Fura-2 ratiometric method gave the following results. (1) L-Glutamate (100 microM) caused [Ca2+]i to increase from the resting level of 75.4+/-36.8 nM (mean +/-S.D., n = 11) to the maximum level (2.2+/-1.4 microM, n = 11) within 15 s and then to decrease to a steady level of 0.59+/-0.23 microM (n = 11). (2) Nifedipine (100 microM) lowered the L-glutamate-induced steady [Ca2+]i level, which was still higher than the resting level. (3) L-Glutamate caused [Ca2+]i to increase even after blockading the voltage-gated Ca2+ channels by nifedipine or by clamping the membrane voltage at -55 mV. (4) (Na+)-free superfusate elevated the L-glutamate-induced steady [Ca2+]i level. (5) The time course of the [Ca2+]i decrease from the L-glutamate-induced steady level to the resting level was prolonged in the (Na+)-free superfusate. These results suggest that the (Na+)-Ca2+ exchanger extrudes intracellular Ca2+ to maintain a low [Ca2+]i level by counteracting the continuous Ca2+ influx through the voltage-gated Ca2+ channels and glutamate-gated channels when horizontal cells in situ are tonically depolarized by L-glutamate released from the photoreceptors. The (Na+)-Ca2+ exchange current isolated by a voltage-clamp experiment depends exponentially on the membrane potential.
Animals↗
Visualization of clear echocardiographic images with near field noise reduction technique: experimental study and clinical experience.
BACKGROUND: With transthoracic echocardiography, it is sometimes difficult to obtain a clear image of the apical portion of the heart because of noise near the transducer. To reduce this artifact, we have developed a new technique (near field noise reduction, NFNR) based on the digital filtering by using radiofrequency signals. This technique may be useful for the accurate measurement of the wall thickness of the myocardium in the near field. The objectives of these studies were (1) to determine the accuracy of this new technique for the measurement of wall thickness in the experimental study and (2) to determine whether the improvement in the image quality in the apical portion can be obtained in the clinical setting by using the NFNR technique. EXPERIMENTAL STUDY: By using the NFNR technique, we measured wall thickness of three kinds of phantoms (wall thickness 9.0, 14.0, and 21.0 mm) moving at various velocities (5 to 80 mm/sec) in the water bath with artifact produced by a single probe. It was difficult to obtain clear echocardiographic images of the phantom and measure its wall thickness because of the artifact. By using the NFNR technique, on the other hand, the same phantom was clearly imaged. It was possible to measure the wall thickness of each phantom at each moving velocity with the NFNR technique. Mean differences between the echocardiographic measurement and actual value of wall thickness in each phantom model (9.0, 14.0, and 21.0 mm) were 0.04 +/- 0.58 mm, 0.09 +/- 0.58 mm, and -0.02 +/- 0.24 mm, respectively. CLINICAL STUDY: We studied 25 initial patients in whom the near field was not clearly imaged in apical views by conventional echocardiography because of near field noise. Apical four-chamber or two-chamber views were obtained with and without the NFNR technique. Two observers independently graded endocardial visualization for the 50 segments by using a three-point scale (0 = endocardium not seen, 1 = seen in part but not all of the segment, 2 = endocardium seen along entire segment). The mean segment score in the imaging with the NFNR technique was significantly higher than that without the NFNR technique (observer 1: 1.8 +/- 0.7 vs 1.2 +/- 0.8, p < 0.01; observer 2: 1.6 +/- 0.7 vs 1.2 +/- 0.8, p < 0.01). CONCLUSIONS: The newly developed NFNR technique provides clear echocardiographic images and accurate wall thickness measurement in the experimental model even when it is difficult to obtain clear images because of the artifact. This new technique will be useful in the reduction of near field noise in the clinical setting.
Echocardiography↗
Diversity revealed by a novel family of cadherins expressed in neurons at a synaptic complex.
In mammals, neurons are highly differentiated and play distinctive functions even in the same brain region. We found a novel cadherin-related neuronal receptor (Cnr) gene family by studying Fyn-binding activity in mouse brain. CNR1 protein is located in the synaptic junction and forms a complex with Fyn. Sequence analysis of eight Cnr products of approximately 20 genes indicates that these comprise a novel cadherin family of the cadherin superfamily. The expression patterns of each member of this novel family were grossly similar to each other but restricted to subpopulations of neurons of the same type. The diversity of the Cnr family genes suggests that there are molecular mechanisms that govern highly differentiated neural networks in the mammalian CNS.
Animals↗
Role of the carboxy-terminal region of the GluR epsilon2 subunit in synaptic localization of the NMDA receptor channel.
The synaptic localization of the N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) channel is a prerequisite for synaptic plasticity in the brain. We generated mutant mice carrying the carboxy-terminal truncated GluR epsilon2 subunit of the NMDA receptor channel. The mutant mice died neonatally and failed to form barrelette structures in the brainstem. The mutation greatly decreased the NMDA receptor-mediated component of hippocampal excitatory postsynaptic potentials and punctate immunofluorescent labelings of GluR epsilon2 protein in the neuropil regions, while GluR epsilon2 protein expression was comparable. Immunostaining of cultured cerebral neurons showed the reduced punctate staining of the truncated GluR epsilon2 protein at synapses. These results suggest that the carboxy-terminal region of the GluRepsilon2 subunit is important for efficient clustering and synaptic localization of the NMDA receptor channel.
Afferent Pathways↗
Mutagenic specificity of a derivative of 3-nitrobenzanthrone in the supF shuttle vector plasmids.
3-Nitrobenzanthrone (NBA) is a powerful bacterial mutagen and a suspected human carcinogen present in diesel exhaust and airborne particulates [Enya, T., et al. (1997) Environ. Sci. Technol. 31, 2772-2776]. In the accompanying paper [Enya, T., et al. (1998) Chem. Res. Toxcol. 11, 1460-1467], N-acetoxy-N-acetyl-3-aminobenzanthrone (N-Aco-N-Ac-ABA) was synthesized to yield the DNA adducts of NBA. In this work, to investigate the mutagenic specificity of NBA in human cells, we analyzed mutations induced by N-Aco-N-Ac-ABA using the supF shuttle vector plasmids. Base sequence analysis of 110 and 100 plasmids with mutations in the supF gene propagated in normal cells [WI38-VA13] and nucleotide excision repair deficient cells [XP2OS(SV)], respectively, revealed that the majority of the mutations were base substitutions (85 and 90%) and the rest were deletions and insertions (10 and 15%) in both cell lines. About half of the mutant plasmids had a single base substitution. Of the base substitutions, the most frequent mutation was G.C to T.A transversion (41 and 51%), followed by G.C to A.T transitions (18 and 24%) in either cell. The mutations were distributed not randomly but located at several hot spots, and almost all (nine of ten) hot spots were at the sites of G.C base pairs. The polymerase stop assay in the supF gene revealed that N-Aco-N-Ac-ABA preferentially bound to guanine residues, and mutation sites were generally consistent with the sites where the guanine adducts were formed.
Base Sequence↗
Intercellular adhesion molecule-1 expression in the inner ear of rats following secondary immune reaction in the endolymphatic sac.
An immunological aetiology for inner ear diseases has long been proposed. The endolymphatic sac (ES) is the only immunoprivileged site in the inner ear with a resident population of immunocompetent cells. By keyhole limpet hemocyanin (KLH) challenge into the ES of systemically pre-immunized guinea pigs, we previously demonstrated an infiltration of inflammatory cells into the perilymphatic space of the cochlea. In order to understand the mechanisms involved in the recruitment of immunocompetent cells into the inner ear, and their relation to the development of endolymphatic hydrops (EH), we investigated the expression and time-kinetics of intercellular adhesion molecule 1 (ICAM-1) in the inner ear of systemically pre-immunized rats after antigen (KLH) challenge into the ES, its relation to cell infiltration in the cochlea and subsequent development of EH. By immunohistochemistry, strong ICAM-1 expression was detected in the spiral ligament, suprastrial region, spiral prominence, spiral modiolar veins, spiral collecting venules, surface membrane of the perilymphatic compartment, perilymphatic space and ES of immunized rats, but not of control rats. ICAM-1 expression was detected at 5-6 h, peaked at 10-15 h, and gradually reduced by 2 weeks. Cell infiltration into the cochlea started at 6-12 h and peaked at day one. By 6 h, 50% of challenged rats developed EH. This figure rose to 70% at 12 h, and then gradually reduced. However, immunoreactivity for KLH (antigen) was only detected in the ES. These results emphasize that the sac is the central immunological organ of the inner ear, and suggest that ICAM-1 may play a pivotal role in the aetiology of immune-mediated inner ear diseases through the recruitment of immunocompetent cells into the inner ear and subsequent development of EH.
Animals↗
Effect of roxithromycin on IL-8 synthesis and proliferation of nasal polyp fibroblasts.
Although several studies have demonstrated that low-dose, long-term 14-member macrolides (erythromycin (EM), roxithromycin (RXM), clarithromycin (CAM)) are effective in the treatment of chronic airway diseases like chronic sinusitis and diffuse panbronchiolitis (DPB), the mechanism of action of these drugs is not yet clear. Both these airway diseases are associated with an increase in the proliferation of fibroblasts. Moreover, fibroblasts are also an important source of proinflammatory cytokines such as interleukin-8 (IL-8), that play an important role in the pathogenesis of nasal polyps. Therefore, using primary fibroblast lines derived from nasal polyps, we investigated the effect of RXM on the synthesis of IL-8 and proliferation of nasal polyp fibroblasts (NPF). These fibroblasts were either treated with lipopolysaccharide (LPS) and RXM for 24 h, or pre-incubated with RXM for 24 h and then treated with LPS and RXM for 24 h. The level of IL-8 mRNA in NPF was analysed by reverse transcriptase-polymerase chain (RT-PCR) and the level of IL-8 in culture supernatants was measured by ELISA. Next, the proliferative capacity of NPF after treatment with RXM was analysed by cell counting and 3H-thymidine uptake. RXM had no effect on LPS-induced IL-8 synthesis by NPF. On the other hand, RXM suppressed the proliferation of NPF in a dose-dependent manner. These findings suggest that, although RXM cannot directly inhibit the synthesis of IL-8, it probably reduces IL-8 production by inhibiting the proliferation of NPF.
Anti-Bacterial Agents↗
Effects of inhaled oxygen concentration on fat metabolism during propofol infusion in rabbits.
We have investigated the effect of inhaled oxygen tension on lipid metabolism during propofol infusion. Propofol is supplied as a lipid emulsion containing 10% soybean oil, which is rich in triglycerides (TG). Infused TG are metabolized via three pathways in the liver cell; Krebs cycle, ketogenesis and release as very low density lipoproteins (VLDL) into the blood. For this reason, we measured TG and the products of the three pathways; carbon dioxide, ketone bodies and VLDL. Thirty-two rabbits were anaesthetized under four different conditions: propofol under hyperoxia, normoxia, hypoxia and isoflurane anaesthesia under hyperoxia. Our results indicated that hyperoxia produced more ketone bodies, normoxia more PaCO2 and hypoxia more free fatty acids (FFA) and TG compared with the other propofol infusion groups. We conclude that hyperoxia during propofol infusion facilitated fat metabolism through ketogenesis, while normoxia did so via the Krebs cycle. Also, hypoxia suppressed utilization of TG and VLDL production in the liver.
Anesthetics, Intravenous↗
Complete restoration of normal DNA repair characteristics in group F xeroderma pigmentosum cells by over-expression of transfected XPF cDNA.
XP-F cDNA was cloned into a mammalian expression vector plasmid, and introduced into group F xeroderma pigmentosum (XP-F) cells. Several cell clones possessing transfected XPF cDNA were randomly isolated, and DNA repair characteristics of a clone, XP-FR2, were extensively analyzed. The XP-FR2 cells expressed high level of XPF protein as well as ERCC1 protein, although their parental XP-F cells expressed extremely low level of both proteins. The XP-FR2 cells showed UV resistance comparable to normal human cells, and had normal levels of UV-induced unscheduled DNA synthesis and normal capability to remove cyclobutane pyrimidine dimers and (6-4) photoproducts. Frequencies and types of UV-induced mutations examined by shuttle vector plasmids in XP-FR2 cells were similar to those in normal human cells. These results demonstrate that excision repair defect in XP-F cells is fully corrected by over-expression of XPF cDNA alone, although only partial correction of the cells by XPF cDNA has been reported before.
Base Sequence↗
A spectrum of mutations induced by crotonaldehyde in shuttle vector plasmids propagated in human cells.
A spectrum of crotonaldehyde-induced mutations in the supF gene of the shuttle vector plasmid pMY189 replicated in human fibroblast cells was examined. Base sequence analysis of 104 plasmids with mutations in the supF gene revealed that the majority of the mutations were base substitutions (85%) and the rest were frameshifts (15%). A single base substitution was most frequently found (47%), while 25% had multiple base substitutions and interestingly 13% had tandem (adjacent two) base substitutions. Of the base substitution mutations, 50% were G:C-->T:A transversions and 23% were G:C-->A:T transitions. The mutations were not distributed randomly but were located at several hotspots, most of which were G:C base pairs in 5'-AAGG-3' (or 5'-CCTT-3') sequences. Production of propanodeoxyguanosine adducts may be related to such specificity in the mutation spectrum.
Aldehydes↗
Characterization of molecular defects in xeroderma pigmentosum group F in relation to its clinically mild symptoms.
Xeroderma pigmentosum (XP) complementation group F was first reported in Japan and most XP-F patients reported to date are Japanese. The clinical features of XP-F patients are rather mild, including late onset of skin cancer. Recently a cDNA that corrects the repair deficiency of cultured XP-F cells was isolated. The XPF protein forms a tight complex with ERCC1 and this complex functions as a structure-specific endonuclease responsible for the 5' incision during DNA excision repair. Here we have identified XPF mRNA mutations and examined levels of the mRNA and protein expression in seven primary cell strains from Japanese XP-F patients. The XP-F cell strains were classified into three types in terms of the effect of the mutation on the predicted protein; (i) XPF proteins with amino acid substitutions; (ii) amino acid substituted and truncated XPF proteins; and (iii) truncated XPF protein only. A normal level of expression of XPF mRNA was observed in XP-F cells but XPF protein was extremely low. These results indicate that the detected mutations lead to unstable XPF protein, resulting in a decrease in formation of the ERCC1-XPF endonuclease complex. Slow excision repair of UV-induced DNA damage due to low residual endonuclease activity provides a plausible explanation for the typical mild phenotype of XP-F patients.
Adult↗
Sensitivity of group F xeroderma pigmentosum cells to UV and mitomycin C relative to levels of XPF and ERCC1 overexpression.
The XPF and ERCC1 proteins form a tight complex and function as an endonuclease to incise on the 5'-side of pyrimidine dimers in DNA. Levels of both proteins are extremely low in group F xeroderma pigmentosum (XP-F) cells. We transfected XP-F cells with the plasmids expressing XPF or ERCC1 and examined levels of both proteins in the cells. Although XP-F cells are sensitive to UV and mitomycin C (MMC), cells overexpressing XPF expressed ERCC1 as well and resistance to UV and MMC was restored to the normal level. In contrast, cells overexpressing ERCC1 did not express XPF and were still sensitive to UV and MMC. These results indicate that both the XPF and ERCC1 proteins are required to repair UV- and MMC-induced DNA damage. Even though a high level of ERCC1, which has been presumed to be a catalytic subunit of the endonuclease, is stably present in XP-F cells, ERCC1 protein alone cannot carry out excision repair completely.
Clone Cells↗
Daytime sleepiness and automobile accidents in patients with obstructive sleep apnea syndrome.
We evaluated the rate of automobile accidents and daytime sleepiness using the Epworth sleepiness scale (ESS) in 44 patients with obstructive sleep apnea syndrome (OSAS). We defined the automobile accident score as a sum of two points for every one automobile accident and one point for every near-miss accident. Automobile accidents and near-misses were found in 54.5% and 50.0% in patients with OSAS. Automobile accident score was significantly correlated with the ESS score (r=0.56, P < 0.01). Our findings suggest that ESS score may be useful in detecting patients with the potential risk of automobile accidents associated with daytime sleepiness.
Accidents, Traffic↗
[Detection of enteroaggregative Escherichia coli from sporadic diarrhea patients].
A study of enteroaggregative Escherichia coli (EAggEC) which was recently reported as a causative agent of diarrhea was attempted, by isolating these organisms from the fecal samples collected from sporadic diarrhea patients in Miyazaki Prefecture during the period from January 1993 to April 1998, and by investigating several characteristics of the isolates. By using the PCR method targetting aggR gene which was a transcriptional activator of aggregative adherence fimbria I expression, thirty four strains of aggR(+)-Escherichia coli (E. coli) were detected from 2,652 fecal samples. Twenty nine of these 34 isolates were confirmed as EAggEC by demonstration of aggregative adherence to HEp-2 cells, and the other 5 isolates were not EAggEC because they showed negative adherence to HEp-2 cells. The above mentioned, aggR-PCR method revealed that there were a few non-EAggEC strains with aggR gene. It has been reported that aggregative adherence fimbriae are encoded by the plasmid of about 60 Md. All of the 29 EAggEC isolates possessed plasmids of about 50 Md or more, and these plasmids were suggested to relate to aggregative adherence fimbriae. Sixteen (55%) of the 29 isolates were classified serologically into two serotypes, O111:H21 and O126:H27, and the other 13 isolates were classified into ten groups or more which included a few strains in a group. EAggEC heat-stable enterotoxin 1 (EAST1) gene was demonstrated in nineteen of 29 isolates. In drug susceptibility test, 72%, 59% and 21% of the 29 isolates showed resistance to Ampicillin, Cefazolin, and Streptomycin, respectively.
Bacterial Adhesion↗
Abnormal synaptic transmission in the olfactory bulb of Fyn-kinase-deficient mice.
We studied synaptic transmission in the granule cells in the olfactory bulb of the homozygous Fyn (a nonreceptor type tyrosine kinase)-deficient (fynz/fynz) and heterozygous Fyn-deficient (+/fynz) mice by using slice preparations from the olfactory bulb. Stimulation to the lateral olfactory tract and/or centrifugal fibers to the olfactory bulb evoked field excitatory postsynaptic potentials (fEPSPs) in the granule cells. In +/fynz mice, fEPSPs were augmented by bicuculline, a gamma-aminobutyric acid (GABAA) antagonist and picrotoxin, whereas fEPSPs in fynz/fynz mice were much less sensitive to bicuculline and picrotoxin. Application of D-2-amino-5-phosphonopentanoic acid had no effect but 6-cyano-7-nitroquinoxaline-2,3-dione produced almost complete block of fEPSPs in both +/fynz mice and fynz/fynz mice. (1S,3R)-1-aminocyclo-pentane-1.3-dicarboxylate, an agonist of metabotropic glutamate receptors caused a similar depression of fEPSPs in both +/fynz and fynz/fynz mice. In +/fynz mice tetanic stimulation to the lateral olfactory tract and/or centrifugal fibers induced N-methyl-D-aspartate (NMDA)-dependent long-term potentiation (LTP) of fEPSPs, whereas LTP was impaired in fynz/fynz mice. Our results demonstrate altered functions of GABAA and NMDA receptors in the olfactory system of Fyn-deficient mice.
2-Amino-5-phosphonovalerate↗
Expression of Fos in the rat forebrain following experimental tooth movement.
Orthodontic tooth movement is known to cause pain and discomfort to patients. Mechanically induced inflammatory responses in the periodontium are assumed to be related to the mechanism of pain sensation. An immediate-early gene, c-fos, that is expressed within some neurons following synaptic activation, is widely used as a marker for neuronal activity following noxious or innocuous stimulation. We have recently demonstrated that experimental tooth movement produced Fos induction in the ipsilateral trigeminal subnucleus caudalis and in the bilateral lateral parabrachial nucleus, which is known to be involved in the transmission of nociceptive information. As a further step, we investigated the distribution of Fos-like immunoreactive neurons in the upper brain regions. Twenty-four hours after the commencement of the experimental tooth movement, the Fos-like immunoreactive neurons appeared in the central nucleus of the amygdala (Ce), paraventricular nucleus of the hypothalamus (PVH), and paraventricular nucleus of the thalamus (PV) of the experimental rats. The numbers of the labeled neurons were significantly increased by 639% (P < 0.001) and 644% (P < 0.001) in the ipsilateral and contralateral sides of the Ce, respectively, by 292% (P < 0.001) and 307% (P < 0.001) in the ipsilateral and contralateral sides of the PVH, and by 264% (P < 0.0001) in the PV with respect to sham control rats. These results suggest that nociceptive information caused by experimental tooth movement might be transmitted and modulated in several regions of the forebrain.
Analysis of Variance↗