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Biomedical subjects

K Yagi

Publications and source records attributed to K Yagi.

At least 199 records · Page 11Linked to original sources
PubMed1998

[A survey of opioid use in preanesthetic medication].

A mailing survey was carried out to assess the current practice of sedative premedication in anesthesia. Questionnaires were sent by mail to 77 university hospitals. We especially evaluated use of opioids for premedication. Sixty-one percent (n = 47) of the hospitals answered these questionnaires and 31 percent (n = 15) of them were using opioids for the preanesthetic medication. Pethidine was used most frequently for premedication of all opioids, and morphine was often used for the premedication before cardiac surgery. All opioids were administrated intramusculary both in adults and children.

Adolescent↗
PubMed1997

Adenovirus-mediated transduction with human glial cell line-derived neurotrophic factor gene prevents 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopamine depletion in striatum of mouse brain.

As a novel trial of neuroprotective therapy of neurodegenerative diseases, we have constructed a recombinant adenovirus vector (rAdv) bearing a neurotrophic factor gene to deliver the factor to rescue neurons in vivo. In the present study, human glial cell line-derived neurotrophic factor (hGDNF) was chosen to examine the applicability of our strategy to a mouse model of Parkinson's disease. During the construction of the rAdv, we found that the strong constitutive hGDNF expression unit somehow inhibited the appearance of the rAdv. Therefore we adopted a self-contained tetracycline-regulated expression system to acquire an rAdv expressing hGDNF. By analyzing the condition medium of SH-SY5Y cells infected with our constructed virus vector, we confirmed that biologically active GDNF was successfully expressed in vitro. For an animal study, we delivered this virus vector directly to the C57 black mouse brain and then exposed the animal to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to injure the nigrostriatal dopaminergic neurons. One week after the MPTP exposure, the neuroprotective effect of the virus vector was estimated by measurement of the dopamine content in the striatum of the mouse brain. The mice that had received our constructed virus had significantly higher dopamine levels in their striatum, demonstrating that our rAdv expressing hGDNF has therapeutic potential to protect the nigrostriatal dopaminergic neurons in vivo.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1997

Toxic shock-like syndrome caused by non-group A beta-hemolytic streptococci.

Two patients with rapidly developing shock, multisystem organ failure, and destructive soft-tissue infection caused by groups G and C streptococci are described. Both patients died rapidly despite aggressive treatment. The clinical characteristics cannot be distinguished from those of toxic shock-like syndrome, but Streptococcus pyogenes was not recovered. These strains did not produce any previously identified type of streptococcal pyrogenic exotoxins. These findings suggest that toxic shock-like syndrome can be caused not only by group A but also groups G and C streptococci. The causative strains of toxic shock-like syndrome may have something in common with unknown virulent factors for this syndrome.

Aged↗
PubMed1997

Clinical characteristics of double heterozygotes with familial hypercholesterolemia and cholesteryl ester transfer protein deficiency.

Coronary heart disease (CHD) in familial hypercholesterolemia (FH) may be modified by genetic and/or environmental factors. We described the effect of the cholesteryl ester transfer protein (CETP) gene on CHD in heterozygous FH caused by low density lipoprotein receptor (LDL-R) gene mutation. In 288 unrelated Japanese subjects with heterozygous FH, the allele frequency of an intron 14 G(+1)-to-A mutation (Int14 A) and a missense mutation in exon 15 (Asp442 to Gly, D442G) was 0.3 and 3.0%, respectively. HDL-C levels (1.55 +/- 0.08 mmol/l) in FH patients with heterozygous CETP deficiency were higher than those (1.19 +/- 0.08 mmol/l) in FH without CETP deficiency (P < 0.03), while LDL-C levels in FH with CETP deficiency were moderately reduced. However, two FH patients with CETP deficiency suffered myocardial infarction, and six patients had effort angina pectoris and/or coronary atherosclerosis. No difference in the score of coronary stenosis index (CSI) was found in FH with/without CETP deficiency, although CSI was inversely correlated with HDL-C levels (P < 0.05). Thus, the effect of increased HDL-C levels caused by partial deficiency of CETP is insufficient to prevent CHD in FH.

Adult↗
PubMed1997

Isolation and expression of rat interferon beta gene and growth-inhibitory effect of its expression on rat glioma cells.

Rat interferon beta (IFN beta) was cloned from a part of rat genomic DNA by the polymerase chain reaction (PCR) with reference to the nucleotide sequence data of a mouse IFN beta. The sequence result showed that the clone had 555 bp of open reading frame (ORF) which encoded a 184-amino acid polypeptide. Comparison of our data with those of mouse and human IFN beta revealed 86.7 and 67.6% homology at the nucleotide level, and 76.2 and 48.9% homology at the amino acid level, respectively. This ORF was inserted into an expression vector, pCAGGS, and COS-1 cells were then transfected with the plasmid encapsulated in cationic multilamellar liposomes. From the results of reverse transcription-PCR and cytopathic activity assay, this ORF expressed IFN beta in COS-1 cells. When the cultured cells of rat glioma cell line T9 were transfected with the plasmid, their growth was markedly suppressed due to the expression of rat IFN beta.

Amino Acid Sequence↗
PubMed1997

Inhibition of nitric oxide synthase causes cardiac phenotypic modulation in rat.

Cardiac gene expressions of collagen and contractile proteins were examined in rats treated with a nitric oxide (NO) synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), for 3 weeks. The rats became hypertensive, which caused left ventricular hypertrophy. Among the mRNAs examined, beta-myosin heavy chain was increased and alpha-myosin heavy chain was decreased in both left and right ventricles, whereas skeletal alpha-actin and atrial natriuretic polypeptide were increased in the left ventricle only. Furthermore, coadministration of losartan with L-NAME lowered blood pressure and caused regression of left ventricular hypertrophy, but did not affect beta- and alpha-myosin heavy chain mRNA levels, indicating that L-NAME directly regulates beta- and alpha-myosin heavy chain mRNA.

Angiotensin II↗
PubMed1997

Growth suppression and induction of heat-shock protein-70 by 9-cis beta-carotene in cervical dysplasia-derived cells.

The aim of the present study was to determine to what extent 9-cis beta-carotene, one of the most abundant naturally-occurring cis-isomers of beta-carotene, can inhibit the growth of cervical dysplasia-derived cells in comparison with all-trans beta-carotene. We found that 9-cis beta-carotene was dose-dependently more effective than all-trans beta-carotene. Both carotenes induced the intracellular accumulation of heat-shock protein-70 (HSP70), and the treated cells showed morphological changes indicative of apoptosis. The results of the present study strongly suggest that the induction of HSP70 by beta-carotene might be involved in beta-carotene-mediated suppression of the cell growth through apoptosis.

Cell Division↗
PubMed1997

Two different pathological conditions of photoparoxysmal responses in hereditary dentatorubral-pallidoluysian atrophy.

In order to reveal the pathophysiology of photoparoxysmal responses (PPRs) in photosensitive patients with hereditary dentatorubral-pallidoluysian atrophy (DRPLA) who had expansion of the CAG repeat in the DRPLA gene, we studied the characteristics of PPRs using optical filters with specific wavelength transmission. In two patients, the wavelength spectrum around 700 nm (670-720 nm) was apparently the only visible range essential for eliciting PPRs, and flash lights containing the essential wavelength elicited PPRs. In another patient, PPRs were elicited by flash lights above certain quantity of light and independent of the wavelength composition of the lights. These data suggest that two different pathological conditions contribute to PPRs in DRPLA patients; one condition depends on the essential wavelength spectrum around 700 nm, and the other not on the wavelength, but on the quantity of light. The condition contributing to PPRs in all three patients was not determined directly by the level of the CAG repeat expansion in the DRPLA gene.

Adult↗
PubMed1997

Effects of single and repeated administration of sulthiame on amygdaloid kindled seizures in rats.

In this study, we assessed the anti-convulsive effects of sulthiame (SUL) in amygdaloid (AM) kindled rats. Electrodes were implanted into the left AM of adult male Wistar rats. The animals were kindled at the after-discharge (AD) threshold. Upon completion of kindling, a generalized seizure triggering threshold was determined. The drugs were administered intraperitoneally in rats which reproducibly exhibited generalized convulsions at the near-threshold stimulation. Single administration of SUL (25-200 mg; n = 7-9) reduced the forelimb clonus (FCL) duration, but only the highest dose significantly regressed the secondarily generalized convulsion. During repeated administration of SUL, 50 mg/kg for 8 days, FCL duration was significantly alleviated until the fifth treatment day. With the dose of 200 mg/kg, significant suppression of secondary generalization was noted only until the second test day. On the other hand, significant reductions of FCL and AD duration were preserved afterwards. The anti-convulsive effects of SUL indicated in this study were not comparable to those of other standard anti-epileptic drugs reported from our laboratory.

Amygdala↗
PubMed1997

Effect of callosal bisection on seizure development and interhemispheric transfer effects in feline motor cortical kindling.

Motor cortical (MC) kindling was carried out in 12 adult cats, seven with the corpus callosum (CC) intact and five with the CC bisected, to study interhemispheric transfer effects and the effect of callosal bisection on both seizure development and interhemispheric transfer effects. MC kindling developed from partial motor seizures to partial onset generalized convulsions. Interhemispheric negative transfer effect, but not positive, existed in secondary site kindling and primary site retest of the CC-intact group, as shown by: (i) electroencephalographically lateralized seizure development in the stimulated hemisphere; (ii) delayed generalization of partial onset generalized convulsions; and (iii) a markedly unstable generalized convulsive seizure state. The CC-bisected group showed: (i) significantly delayed seizure development from partial motor seizure stage to generalized convulsive seizure stage in primary and secondary kindling; (ii) facilitated intrahemispheric seizure development; (iii) the diminution of interhemispheric negative transfer effect; (iv) modified generalized convulsions showing extremely asymmetrical generalized convulsions shifting from contralaterally dominant convulsions to ipsilaterally dominant ones (n = 2) or alternate generalized convulsions changing from contralateral hemiconvulsions to ipsilateral ones (n = 3). The results obtained suggest that the CC plays a major role in interhemispheric seizure propagation as well as interhemispheric negative transfer effects in MC kindling and may have suppressive effect on intrahemispheric motor seizure development in MC kindling. However, interhemispheric seizure propagation and interhemispheric negative transfer effects were mediated via other structures, possibly subcortical structures, when the CC was bisected.

Animals↗
PubMed1997

Effect of motor cortical kindling on subsequent ventral hippocampal kindling and the role of the corpus callosum in the cat.

The effect of bilateral motor cortical (MC) kindling on subsequent unilateral ventral hippocampal (VHIPP) kindling was studied in four cats with the corpus callosum (CC) intact and five cats with the CC bisected, compared with nine cats with unilateral VHIPP kindling. Subsequent VHIPP kindling in CC-intact cats resulted in the modified development of limbic seizures to ipsilateral, not contralateral, focal motor seizures in one of four cats, significantly greater seizure regressions from generalized convulsive seizure stage to earlier seizure stages and delayed onset of focal motor seizures and generalized convulsions in partial onset generalized convulsions. CC bisection reduced the degree of seizure regression from generalized convulsive seizure stage to earlier stages, facilitated the development of the last limbic seizure to the first generalized convulsive seizure, accentuated hemiconvulsions and asymmetrical generalized convulsions and delayed the onset of generalized convulsions in partial onset generalized convulsions. The modified seizure development was also induced in three of five CC-bisected cats. Results indicate that bilateral MC kindling induces inhibitory effects on subsequent unilateral VHIPP kindling and the modified ictal progress from the VHIPP to the contralateral hemispheric motor structures and also that CC bisection interferes with the bilateralization and synchronization of convulsions, but reduces the inhibition of previously established MC kindling against VHIPP kindling and facilitates the development of focal motor seizures to secondarily generalized convulsions.

Animals↗
PubMed1997

Mechanism of acid secretory changes in rat stomach after damage by taurocholate: role of nitric oxide, histamine, and sensory neurons.

The present study was performed to investigate the mechanism underlying the acid stimulatory response in the stomach after damage under the inhibition of nitric oxide (NO) production by N(G)-nitro-L-arginine methyl ester (L-NAME). A rat stomach was mounted in an ex vivo chamber, perfused with saline, and the potential difference (PD) and acid secretion were measured before and after the application of 20 mM taurocholate (TC) for 30 min. Exposure of the stomach to TC caused a PD reduction and a decrease of acid secretion. Pretreatment with L-NAME did not affect basal acid secretion but significantly enhanced the acid secretion in the stomach after damage with TC, without any effect on the PD response. This effect of L-NAME was antagonized by simultaneous administration of L-arginine but not D-arginine. The luminal appearance of NO was significantly increased in the stomach after exposure to TC, and this change was completely blocked in the presence of L-NAME or when EGTA was applied together with TC. The enhanced acid secretory response to TC in the presence of L-NAME was inhibited by pretreatment with cimetidine, FPL-52694 (a mast cell stabilizer), or spantide (a substance P antagonist) or by chemical ablation of capsaicin-sensitive sensory neurons. Mucosal exposure to TC increased histamine output in the lumen and decreased the number of metachromatically staining cells in the stomach, and these changes were also significantly prevented by FPL-52694, spantide, or sensory deafferentation. These results suggest that 1) damage in the stomach may activate the acid stimulatory pathway in addition to the NO-dependent inhibitory mechanism, but the latter effect overcomes the former, resulting in a decrease in acid secretion, 2) the acid stimulation in the damaged stomach may be mediated by histamine released from the mucosal mast cell which may interact with capsaicin-sensitive sensory nerves, and 3) L-NAME unmasks the acid stimulatory response by suppressing the inhibitory mechanism.

Animals↗
PubMed1997

Roles of prostaglandin E-receptor subtypes in gastric and duodenal bicarbonate secretion in rats.

BACKGROUND & AIMS: Receptors activated by prostaglandin (PG) E2 are pharmacologically subdivided into four subtypes (EP1-EP4). The EP-receptor subtype(s) involved in stimulation of gastroduodenal HCO3- secretion in rats were investigated. METHODS: Under urethane anesthesia, a stomach mounted in an ex vivo chamber or a proximal duodenal loop was perfused with saline, and HCO3- secretion was measured using a pH-stat method. RESULTS: Intravenous PGE2 increased HCO3- secretion by the gastroduodenal mucosa; this action was verapamil sensitive and, only in the duodenum, potentiated by isobutylmethyl xanthine (IBMX). Duodenal HCO3- secretion was stimulated by enprostil, sulprostone (EP1/EP3 agonist), misoprostol (EP2/EP3 agonist), and ONO-NT012 (EP3 agonist) but was not affected by butaprost (EP2 agonist) or 17-phenyl-PGE2 (EP1 agonist). Gastric HCO3- secretion was stimulated by sulprostone, enprostil, and 17-phenyl-PGE2 but not by misoprostol, butaprost, or ONO-NT012. SC-51089 (EP1 antagonist) inhibited the HCO3--stimulatory action of sulprostone only in the stomach. IBMX potentiated the HCO3- response to sulprostone in the duodenum, whereas verapamil reduced the response in both the stomach and duodenum. CONCLUSIONS: PGE stimulates HCO3- secretion via different EP-receptor subtypes in the stomach and duodenum: in the stomach, EP1 receptors are linked to Ca2+; in the duodenum, EP3 receptors are coupled with both adenosine 3', 5'-cyclic monophosphate and Ca2+.

1-Methyl-3-isobutylxanthine↗
PubMed1997

Effect of selenium on human phospholipid hydroperoxide glutathione peroxidase expression and host cell susceptibility to lipid hydroperoxide-mediated injury.

We recently isolated stable transfectants expressing human phospholipid hydroperoxide glutathione peroxidase (PHGPx) from the cells of guinea pig cell line 104C1 (Biochem. Biophys. Res. Commun. 219, 486-491, 1996). Among them, one transfectant, designated 104C1/O4C, expressed high glutathione peroxidase activity toward dilinoleoyl phosphatidylcholine hydroperoxide (PCOOH); and another one, 104C1/O2D, moderate activity. In the present study, we investigated the effect of selenium on the PHGPx activity and on the lipid hydroperoxide-mediated cell injury in the transfectants to clarify further the action of PHGPx in preventing oxidative injury of the cells. When transfectant 104C1/O2D cells were cultured in the medium added with 250 nM selenium, glutathione peroxidase activity toward PCOOH increased 8-fold. Western blot analysis also revealed an increase in the amount of protein immunoreactive against anti-rat PHGPx antibody in this transfectant. Lipid hydroperoxide-mediated cell injury to the transfectant 104C1/O2D was significantly suppressed in accordance with the increase in the enzyme activity when the cells were cultured in the medium added with selenium. On the contrary, neither glutathione peroxidase activity toward PCOOH nor susceptibility to the injury was affected by selenium addition to the medium of the parental 104C1 cells, which have no selenium-dependent glutathione peroxidase. These results clearly support our previous conclusion that expression of PHGPx is responsible for the protection of host cells from lipid hydroperoxide-mediated injury.

Animals↗
PubMed1997

Ring chromosome 20 and nonconvulsive status epilepticus. A new epileptic syndrome.

Six cases of epilepsy associated with ring chromosome 20 are presented. The study of these cases and 20 cases reported in the literature revealed that they constitute a distinct epileptic syndrome: frequent seizures consisting of a prolonged confusional state, with or without additional motor seizures, and an ictal EEG pattern of long-lasting bilateral paroxysmal high-voltage slow waves with occasional spikes. Neurological examination results were normal, and neuroimaging studies often failed to disclose a brain lesion. The seizures were resistant to antiepileptic drug therapy. Comparison of the electroclinical features of nonconvulsive status epilepticus in six patients with and four patients without ring chromosome 20 revealed that the group with the chromosomal anomaly had more frequent, comparatively brief episodes of confusion associated with a less prominent spike component on the EEG. We propose that epilepsy associated with ring chromosome 20 constitutes a new syndrome that may provide an opportunity to scrutinize a genetic mechanism of epilepsy.

Adolescent↗
PubMed1997

Reconstruction following total laryngopharyngoesophagectomy and extensive resection of the superior mediastinum.

Our experience with four patients who underwent immediate reconstruction following total laryngopharyngoesophagectomy and extensive resection of the superior mediastinum is presented. The reconstructive procedures included free jejunal graft or microvascularly augmented gastric pedicle for esophageal reconstruction, pectoral fasciocutaneous or myocutaneous flap for tracheal reconstruction, and mesenteric flap connected with jejunal graft omental flap, or pectoral flap for protection of the great vessels and obliteration of the dead space in the cervical and superior mediastinal region. The reconstructive procedures were successful, and no pharyngocutaneous fistula, mediastinitis, or great vessel rupture was noted in any patient. There was one patient who developed lung edema and liver dysfunction postoperatively. Combinations of reconstructive procedures using well-vascularized soft tissues can be expected to provide well-tolerated reconstruction following extensive cervical and superior mediastinal resection.

Aged↗