Biomedical subjects

K Nishi

Publications and source records attributed to K Nishi.

At least 91 records · Page 5Linked to original sources

PubMed1999

[Relationship between biological activity and heparin-affinity sites of recombinant human basic fibroblast growth factor CS23 mutein].

A recombinant human basic fibroblast growth factor CS23 mutein (rhbFGF-CS23) obtained from Escherichia coli cells has proliferation-stimulating activity for a fetal bovine heart endothelial cell line, ATCC CRL 1395 (biological activity), and strong affinity for heparin (heparin-affinity) similarly to the natural human basic fibroblast growth factor. Plural species having different kinds of heparin-affinity were formed by acetylation of rhbFGF-CS23 with acetic anhydride. To clarify the relationship between the sites with heparin-affinity and the biologically active sites, we have investigated the acetylation sites by peptide mapping and the biological activity of the acetylated species. Consequently, the sites with heparin-affinity in rhbFGF-CS23 are found to be Lys26, Lys119, Lys125, Lys129, and Lys135 in the primary structure, and these sites with heparin-affinity except Lys26 are also clarified to be very important to retain the biological activity of the factor.

Acetylation↗

PubMed1999

Alkalinization-induced K+ current of the mouse megakaryocyte.

We have recently found that mouse megakaryocytes responded to extracellular alkalinization to pH > 8.0, generating a K+ current under voltage-clamped conditions with the whole cell recording mode of the patch-clamp technique. The purpose of this study was to physiologically and pharmacologically characterize the alkaline-dependent K+ conductance of the megakaryocyte membrane. The alkalinization-induced K+ current (I(ALK)) did not seem to be Ca2+-dependent since I(ALK) was allowed to be generated under intracellularly Ca2+-buffered conditions with 10 mM EGTA, which completely prevented the generation of caffeine-induced Ca2+-activated currents of mouse megakaryocytes; and no [Ca2+]i elevation was evoked by the alkalinization protocol in contrast to a significant increase in [Ca2+]i in response to caffeine when [Ca2+]i was measured with a fura 2 ratiometry. I(ALK) was strongly suppressed with tetraethylammonium (TEA), 4-aminopyridine (4-AP) and streptomycin (SM), but was completely resistant to quinidine (QND). The values of IC50 for the suppression of I(ALK) with TEA, 4-AP and SM were 5.6, 0.47 and 1.5 mM, respectively. Voltage-gated K+ currents (I(K)) of the same megakaryocyte preparation were weakly suppressed with TEA and 4-AP, while they were significantly suppressed with either SM or QND. These results suggest that mouse megakaryocytes possess K+ conductance that was activated by extracellular alkalinization and that probably differs from conventional K+ conductance in its pharmacological properties.

4-Aminopyridine↗

PubMed1999

Dipeptidyl peptidase III from rat liver cytosol: purification, molecular cloning and immunohistochemical localization.

Dipeptidyl peptidase III (DPP III) was purified to homogeneity from rat liver cytosol. The calculated molecular weight of the purified enzyme was 82845.6 according to TOF-MS and 82000 on non-denaturing PAGE, and 82000 on SDS-PAGE in the absence or presence of beta-mercaptoethanol. These findings suggest that the enzyme exists in a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrate Arg-Arg-MCA and moderately hydrolyzed Gly-Arg-MCA in the pH range of 7.5 to 9.5. The Km, k(cat) and k(cat)/Km values of DPP III at optimal pH (pH 8.5) were 290 microM, 18.0 s(-1) and 62.1 s(-1) x nM(-1) for Arg-Arg-MCA and 125 microM, 4.53 s(-1) and 36.2 s(-1) x nM(-1) for Ala-Arg-MCA, respectively. DPP III was potently inhibited by EDTA, 1,10-phenanthroline, DFP, PCMBS and NEM. These findings suggest that DPP III is an exo-type peptidase with characteristics of a metallo- and serine peptidase. For further information on the molecular structure, we screened a rat liver cDNA library using affinity-purified anti-rat DPP III rabbit IgG antibodies, determined the cDNA structure and deduced the amino acid sequence. The cDNA, designated as lambdaRDIII-11, is composed of 2640 bp and encodes 738 amino acids in the coding region. Although the enzyme has a novel zinc-binding motif, HEXXXH, DPP III is thought to belong to family 1 in clan MA in the metalloprotease kingdom. The DPP III antigen was detected in significant amounts in the cytosol of various rat tissues by immunohistochemical examination.

Amino Acid Sequence↗

PubMed1999

Coronary artery stenosis evaluated by combined carotid and coronary angiography in patients undergoing carotid endarterectomy.

The relationship between coronary artery stenosis and the postoperative outcome was investigated in patients who underwent carotid endarterectomy (CEA). The benefit of combined carotid and coronary angiography was also evaluated. Combined carotid and coronary angiography was performed in 72 patients treated with CEA (mean age 64.0 years). Fourteen patients with a history of ischemic heart disease (IHD) had a higher Gensini score for coronary artery stenosis than patients with no history of IHD (37.9 +/- 36.8 vs. 7.9 +/- 12.5, p < 0.0001). However, 39.7% of patients with no history of IHD had a Gensini score exceeding 6. Patients with diabetes mellitus had a significantly higher Gensini score than nondiabetic patients. Eleven patients (15.3%) underwent percutaneous transluminal coronary angioplasty and three (4.2%) underwent coronary artery bypass grafting during the CEA perioperative period. None of the patients who underwent combined angiography showed signs of IHD during or after CEA (mean follow-up period 30 months). Combined angiography was not performed in 189 previous patients. Of these, two died of acute myocardial infarction in the postoperative period, 11 manifested nonfatal IHD, and 18 succumbed to IHD (mean follow-up period 8 years). Although patients with a history of IHD manifested more severe coronary artery stenosis than patients without such a history, the possibility of coronary artery stenosis must be considered in patients with no history of IHD, especially those with diabetes mellitus. Combined carotid and coronary angiography and careful management of coronary artery stenosis can be expected to decrease the mortality and morbidity in patients treated with CEA.

Adult↗

PubMed1999

[Judicial judgements on anesthesia malpractice in Japan].

We reviewed 75 judicial precedents on anesthetic malpractice during surgical procedure which had appeared in legal journals in the period between 1963 and 1997. Anesthetic techniques employed were: general anesthesia (35 cases), spinal anesthesia (19 cases), local anesthesia (12 cases), and others (9 cases). Anesthesiologists were involved in 16 lawsuits, of which anesthesiologists lost 6 suits between 1986 and 1995. There were 8 cases classified as to be caused by respiratory problems including 2 cases of wrong gas supply. The defendants lost all the 8 cases. On the other hand, the plaintiff lost all the cases of malignant hyperthermia (n = 7). There is a tendency of increase in law suit with general anesthesia. Recent judgments suggested the importance of anesthetic managements, correct recording and appropriate monitoring by anesthesiologist during and immediately after surgery. Spinal anesthesia should be performed by anesthesiologist, and the frequency of anesthetic accident should be decreased. Japan is still in short of anesthesiologists and efforts should be paid to increase the number of anesthesia specialists.

Anesthesia↗

PubMed1999

[An autopsy case of a bicycle accident with ring fracture at the base of the skull].

We report the autopsy case of a 41-year old passenger who suffered a significant head injury with a typical ring fracture at the base of the skull as a result of a violent fall from a bicycle. Several reports about ring fractures of the base of the skull revealed that they were due to crashing a car at high speed, a collision and/or a fall while riding a motorcycle and a fall in piloting a gyrocopter and so on resulting in severe injury to another part of the body. In this case, the ring fracture occurred when his spine was pushed up by high impact of the parieto-occipital region against the ground.

Accidents, Traffic↗

PubMed1998

The accumulation of cyclin-dependent kinase inhibitor p27kip1 is a primary response to staurosporine and independent of G1 cell cycle arrest.

The staurosporine-induced G1 cell cycle arrest was analyzed in a variety of cell lines which includes human tumor cell lines and oncogene-transformed NIH3T3 cell lines. All the cell lines which were sensitive to staurosporine-induced G1 arrest contained a functional retinoblastoma protein (pRB). However, when pRB-lacking fibroblast cells derived from pRB knockout mice were tested they were also sensitive to G1 arrest by staurosporine, indicating that the inactivation of pRB alone is not sufficient for the abrogation of staurosporine-induced G1 arrest. In searching for a common event caused by staurosporine, the cyclin-dependent kinase (CDK) inhibitor protein p27kip1 but not p21cip1 was found to accumulate after staurosporine treatment in all the cell lines examined. This accumulation occurred regardless of the induction of the G1 arrest. The result indicates that the accumulation of p27kip1 is the cell's primary response to staurosporine and that the capability of staurosporine to induce G1 arrest depends on the integrity of cell cycle regulatory components which are downstream of p27kip1.

3T3 Cells↗

PubMed1998

Do all of human midbrain tyrosine hydroxylase neurons synthesize dopamine?

We examined whether all of human midbrain tyrosine hydroxylase (TH) neurons substantially synthesize dopamine (DA) using dual labeling immunohistochemical technique of TH and aromatic L-amino acid decarboxylase (AADC). In the substantia nigra, besides many neurons doubly stained for TH and AADC, neurons stained only for TH and only for AADC (D-neurons [C.B. Jaeger, D.A. Ruggiero, V.R. Albert, T.H. Joh, D.J. Reis, Immunocytochemical localization of aromatic l-amino acid decarboxylase, in: A. Björklund, T. Hökfelt (Eds.), Handbook of Chemical Neuroanatomy, Classical Transmitters in the CNS, Vol. 2, Part 1, Elsevier, Amsterdam, 1984, pp. 387-408.]) were identified. In the ventral tegmental area, dually labeled neurons and TH-only-positive neurons were found. It is indicated that the number of midbrain TH neurons does not reflect the exact number of DA neurons.

Adult↗

PubMed1998

Postural effects of unilateral blockade of glutamatergic neurotransmission in the subthalamic nucleus on haloperidol-induced akinesia in rats.

The present study examined the postural effects of the local application of glutamatergic antagonists unilaterally into the subthalamic nucleus (STN), on haloperidol-induced akinesia in rats. After intracerebral injections of MK-801, a selective antagonist of N-methyl-D-aspartate (NMDA) receptor, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) disodium, a selective alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor antagonist, or vehicle, unilaterally into the STN, haloperidol was administered systemically and the elicited behaviors were assessed quantitatively. In rats which received injections of MK-801 or CNQX, but not vehicle, unilaterally into the STN, the administration of haloperidol induced contraversive dystonic posturing. The severity of the deviated posturing was dose-dependent. The present findings revealed that the overactivity of the STN under conditions of dopamine blockade is suppressed by interruptions of glutamatergic inputs, mediated via both NMDA or AMPA receptors, to the STN. Therefore, the present study may provide functional evidence in support of a recently proposed hypothesis, that not only disinhibition from the inhibitory globus pallidus efferents but also excitatory glutamatergic inputs to the STN actually contribute to the overactivity of the STN under dopamine-depleted conditions.

6-Cyano-7-nitroquinoxaline-2,3-dione↗

PubMed1998

Globus pallidus lesions inhibit the induction of c-Fos by haloperidol in the basal ganglia output nuclei in rats.

This study examined the induction of c-Fos expression in the substantia nigra pars reticulata (SNr) and entopeduncular nucleus (EP) in the rats with a globus pallidus (GP) lesion, following the administration of haloperidol. After a GP lesion was made unilaterally by stereotaxic administration of ibotenic acid, haloperidol was administered systemically, and the number of cells expressing c-Fos was quantitatively assessed. Haloperidol induced a high level of the expression of c-Fos in neurons of the SNr and EP, and the GP lesion significantly decreased the expression of c-Fos in the ipsilateral SNr and EP. Since it has been suggested that c-Fos expression in the SNr/EP is caused by increased excitatory inputs from the subthalamic nucleus (STN), the present results provide functional evidence indicating that neuronal activities of the basal ganglia output nuclei are not increased by GP ablation, unlike D2 receptor blockade, supporting the recently proposed hypothesis that overactivity of the STN resulting from dopamine depletion is not solely a result of disinhibition from inhibitory GP efferents.

Animals↗

PubMed1998

The properties of caffeine- and carbachol-induced intracellular Ca2+ release in mouse bladder smooth muscle cells.

Freshly dissociated bladder smooth muscle cells of mice developed spontaneous, caffeine- (ICAF) and carbachol-induced (ICCh) currents under voltage-clamped conditions. Spontaneous currents, ICAF and ICCh were blocked with tetraethylammonium at 3 x 10(-4)-10(-2) M but were resistant to both charybdotoxin (10(-7)-10(-6) M) and iberiotoxin (10(-7)-10(-6) M). The reversal potential for each current indicated that K+ channels play a major role in the generation of each current. Both spontaneous currents and ICAF but not ICCh were abolished in nominally Ca2+-free and nicardipine (10(-6) M)-containing media. These results suggest that the activity of L-type voltage-sensitive Ca2+ channels is important in the generation and maintenance of spontaneous currents and ICAF but not ICCh. Ryanodine (10(-6) M) prevented spontaneous currents, ICAF and caffeine-induced [Ca2+]i elevation but not ICCh and carbachol-induced [Ca2+]i elevation, suggesting that the response of bladder smooth muscle cells to carbachol may involve a Ca2+ store distinct from that for caffeine. Pretreatment with carbachol suppressed ICAF to 22 +/- 7% (n = 7) and the caffeine-induced [Ca2+]i elevation to 25 + 3% (n = 6). Similarly, caffeine suppressed ICCh to 23 +/- 4% (n = 9) and the carbachol-induced [Ca2+]i elevation to 24 +/- 6% (n = 6).

Animals↗

PubMed1998

A dopamine-synthesizing cell group demonstrated in the human basal forebrain by dual labeling immunohistochemical technique of tyrosine hydroxylase and aromatic L-amino acid decarboxylase.

The human basal forebrain has been known to contain many neurons immunoreactive (ir) to tyrosine hydroxylase (TH; the first dopamine-synthesizing enzyme). We examined whether these neurons might contain aromatic L-amino acid decarboxylase (AADC; the second step dopamine-synthesizing enzyme) by dual labeling immunohistochemistry and confocal laser-scanning microscopy. Neurons dually-labeled for TH and AADC were found in the anterior olfactory nucleus, olfactory tubercle and the ventral margin of the rostral nucleus accumbens. The examination in the basal forebrain of the macaque monkey also gave substantially the same results. These neurons appear to constitute an independent dopaminergic cell group in the primate basal forebrain.

Adult↗

PubMed1998

Genetic and alkaloid analysis of Papaver species and their F1 hybrid by RAPD, HPLC and ELISA.

Total DNA was extracted from the leaves of a F1 hybrid and its parents, Papaver bracteatum Lindle and P. pseudo-orientale Medw. Analysis of random-amplified polymorphic DNA (RAPD) using ten arbitrary oligonucleotide 10-mers, showed that F1 hybrid was confirmed to be genetically intermediate of both parental plants compared with the genetic distance between F1 hybrid and individual parents. Furthermore, the comparison of the band patterns between a F1 hybrid, P. bracteatum and P. pseudo-orientale clearly showed that part of the bands of both parents were induced into a F1 hybrid. The content of thebaine was determined by HPLC and ELISA used anti-thebaine monoclonal antibody.

Alkaloids↗

PubMed1998

Dystonic posturing and circling behaviors induced by dopaminergic agents in rats with unilateral globus pallidus lesions.

The present study examined the behavioral effects of dopamine receptor agonists, antagonists, or N-methyl-D-aspartate (NMDA) glutamate receptor antagonist in rats with a unilateral excitotoxic lesion of the globus pallidus (GP). After the unilateral GP lesions were made by injections of the ibotenic acid, drugs were systemically given and the elicited behaviors were quantitatively assessed. Systemic administration of haloperidol, but not SCH23390, dose-dependently induced contraversive dystonic posturing in unilateral GP-lesioned rats. On the other hand, systemic administration of quinpirole, but not SKF38393, induced ipsiversive circling. MK-801, only when given at a high dose, unilateral GP-lesioned rat, the D2 receptor agonist and antagonist caused ipsiversive and contraversive posturing or circling, respectively. Since the rotational behavior is induced on the basis of asymmetry of the basal ganglia output activity, there must be a marked difference between the GP ablation and the administration of D2 receptor blockade on the basal ganglia output activity, supporting a speculation that overactivity of the basal ganglia under dopamine depletion is not solely a result of the disinhibition from the inhibitory GP efferents. The present unilateral GP-lesion model appears to be a useful one for the pharmacobehavioral investigation of D2-mediated mechanisms.

Analysis of Variance↗

PubMed1998

Effects of the globus pallidus lesion on the induction of c-Fos by dopaminergic drugs in the striatum possibly via pallidostriatal feedback loops.

c-Fos is one of the transcription factors contributing to the regulation of the downstream gene expression. Administration of dopamine D1 receptor agonist or D2 receptor antagonist have been known to induce c-Fos expressions in striatal projection neurons. We examined the effects of unilateral ablation of the globus pallidus (GP) on apomorphine- or haloperidol-induced expression of c-Fos in the striatum. Haloperidol induced a high level of c-Fos expression in the striatal neurons, predominantly those in the dorsal part, and the unilateral GP lesion caused by ibotenic acid increased the number of neurons exhibiting haloperidol-induced c-Fos expression in the striatum on the side with the GP lesion by about 2- or 3-fold. On the other hand, the unilateral GP lesion had no significant effect on the apomorphine-induced c-Fos expression in the striatal neurons. The present study provides evidence indicating that the activity of GP neurons may have an inhibitory influence on the induction of the immediate early genes by haloperidol in the striatal neurons, suggesting a function of the pallido-striatal feedback loops which have been identified anatomically.

Animals↗

PubMed1998

Accommodation amplitude after lens refilling with injectable silicone by sealing the capsule with a plug in primates.

OBJECTIVE: To restore accommodation in primate eyes by refilling the lens capsule with injectable silicone compounds. MATERIALS AND METHODS: Eight eyes of 8 monkeys (Macaca fascicularis) were treated by the lens refilling procedure. To prevent leakage of the injected liquid silicone before it polymerized in the capsule in vivo, a silicone plug for sealing the capsular opening was developed. After endocapsular phacoemulsification following an upper minicircular capsulorhexis, the plug was introduced into the capsulorhexis opening. A silicone mixture was injected into the capsular bag through the delivery tube of the plug. Automated refractometry was performed 1 week and 3 months after surgery. Accommodation amplitude was determined as the difference between the refractions before and 1 hour after topical application of 4% pilocarpine chloride. RESULTS: Five of 8 eyes could be refilled. In 4 of 5 eyes, refraction could be measured. Accommodation amplitude ranged from 1.0 to 4.5 diopters, with a mean of 2.3 +/- 1.3 diopters (8.0 +/- 2.0 preoperative values). At 3-month examination, thick posterior capsule opacification precluded refractometry in all eyes. CONCLUSIONS: The lens refilling procedure with the use of a silicone plug for sealing the capsular opening was feasible in primate eyes. The accommodation amplitude attained was a small fraction of the value before surgery. This may result from the loss of so-called intracapsular accommodation, ie, active participation of lens fiber cells in accommodation. However, since the obtained accommodation may be sufficient for near vision after cataract surgery, this lens refilling procedure warrants further study. Elucidation of the mechanism of intracapsular accommodation may also be necessary.

Accommodation, Ocular↗

PubMed1998

Modulation of calcium responses by altered peptide ligands in a human T cell clone.

To determine whether altered peptide ligands (APL) affect calcium signaling events, we investigated changes in intracellular calcium concentration ([Ca2+]i) in human T cell clone stimulated with either the fully agonistic peptide M12p54-68, the partially agonistic analogue E63V or the simple antagonistic analogue E58M. Both E63V and E58M stimulated a Ca2+ response in approximately 40% of T cells, whereas M12p54-68 did so in approximately 70% of T cells. The most predominant pattern of a Ca2+ increase induced by M12p54-68 was a small sinusoidal peak followed by a sustained high response. The most frequent pattern of calcium response induced by E63V was a continuous high response without a preceding sinusoidal peak, whereas that induced by E58M was large with frequent oscillations. Genistein, an inhibitor of the protein tyrosine kinases (PTK), markedly inhibited the wild-type peptide-induced increase in [Ca2+]i, whereas it marginally inhibited the response induced by E63V or E58M. In contrast, GF109203X, a protein kinase C (PKC)-specific inhibitor, markedly inhibited the E63V- or E58M-induced Ca2+ response, whereas it marginally affected the wild peptide-induced Ca2+ response. Furthermore, in nominal Ca2+-free medium, the E58M-induced Ca2+ response was almost completely blocked, while the M12p54-68- or E63V-induced responses were only partially inhibited. Our results suggest that the Ca2+ response induced by the fully agonistic peptide depends on activation of the genistein-sensitive signaling pathway, including PTK, whereas the Ca2+ response to a simple antagonistic APL completely depends on extracellular Ca2+ and activation of the GF109203X-sensitive signaling pathway, including PKC. These differences in the CA2+i response in recognition of different APL may parallel the unique T cell activation patterns induced by APL in human T cells.

Amino Acid Sequence↗

PubMed1998

Fluorescence based co-amplification and automated detection of the STR loci HUMFIBRA and HUMD21S11 in a Hungarian Caucasian population sample.

Population data were generated for the STR systems HUMFIBRA and HUMD21S11 for a Hungarian Caucasian population sample residing in Baranya County, Hungary (127 unrelated individuals). The loci were coamplified using a fluorescence based PCR method and were typed automatically. For both loci 12 different alleles could be found including some variants. No deviations from Hardy-Weinberg expectations were observed. Both loci proved to be highly discriminating and valuable polymorphisms for forensic analyses.

Alleles↗