Biomedical subjects

M Ishida

Publications and source records attributed to M Ishida.

At least 145 records · Page 8Linked to original sources

PubMed1997

Novel polypeptide toxins with crab lethality from the sea anemone Anemonia erythraea.

The sea anemone Anemonia erythraea was found to contain polypeptide toxins with crab lethality as well as hemolysins. Three polypeptide toxins (AETX I, II and III) were isolated by gel filtration on Sephadex G-50 and reverse-phase HPLC on TSKgel ODS-120T. A geographic variation in toxin composition was suggested. The LD50 against crabs of AETX I, II and III were estimated to be 2.2, 0.53 and 0.28 microg/kg, respectively, but none of the toxins showed lethality in mice. The amino acid sequences of the three toxins were deduced from sequencings of the whole molecules and their enzymatic fragments. Amino acid analyses and molecular mass determinations supported the accuracy of the deduced sequences. AETX I, comprising 47 amino acid residues including 6 half-Cys residues, is an analog of sea anemone type I toxins. On the other hand, AETX II and III, which are highly homologous with each other, are quite distinct from the known sea anemone polypeptide toxins in that they are composed of 59 residues including 10 half-Cys residues. Interestingly, both toxins have sequence similarities with neurotoxins isolated from the Brazilian 'armed' spider Phoneutria nigriventer.

Amino Acid Sequence↗

PubMed1997

DCG-IV, a potent metabotropic glutamate receptor agonist, as an NMDA receptor agonist in the rat cortical slice.

The depolarization induced by DCG-IV, a potent agonist for Group II metabotropic glutamate receptors (Group II mGluRs), was depressed by selective antagonists for NMDA receptors in the rat cortical slice, but was not affected even by a high concentration of a selective antagonist for Group II mGluRs. DCG-IV caused depolarization more effective than NMDA in a dose-dependent manner with a threshold concentration of 3 microM in rat cortical slices, while DCG-IV was less active than NMDA in rat spinal cords. These actions should be carefully considered particularly when DCG-IV is used as an agonist for mGluRs in vivo.

Animals↗

PubMed1997

Interaction between carbamazepine and bromperidol.

OBJECTIVE: The interaction between carbamazepine and bromperidol was studied in 13 schizophrenic inpatients. METHODS: Before carbamazepine addition, the subjects were taking bromperidol 12-24 mg.day-1 for 1-20 weeks. Carbamazepine 400 mg.day-1 was coadministered for 4 weeks, and blood samplings were performed before carbamazepine addition and at weekly intervals after the addition. Plasma concentrations of bromperidol and its reduced metabolite were measured by high-performance liquid chromatography. RESULTS: Carbamazepine significantly decreased plasma concentrations of both bromperidol and reduced bromperidol for all weeks. On average, the plasma concentrations of bromperidol and reduced bromperidol at 4 weeks were 37% and 23% of the corresponding precarbamazepine values. Despite these decreases in plasma concentration, the Clinical Global Impression scores decreased slightly but significantly after carbamazepine addition. CONCLUSION: The present study suggests that carbamazepine decreases plasma concentrations of bromperidol and its reduced metabolite by inducing the metabolism of these compounds. Nevertheless, adjunctive carbamazepine may be useful for schizophrenic patients treated with bromperidol.

Adult↗

PubMed1997

Highly efficient production of enzymes of an extreme thermophile, Thermus thermophilus: A practical method to overexpress GC-rich genes in Escherichia coli.

The GC-rich leuB gene (coding for 3-isopropylmalate dehydrogenase) of Thermus thermophilus is scarcely expressed in Escherichia coli, unless a leader open reading frame (ORF) is provided. We conducted experiments on nonexpressible plasmids and obtained a modified plasmid showing greatly enhanced expression: the degree of expression from the plasmid was higher than that from any other plasmid so far constructed. Sequence analysis of the plasmid showed that a 258-bp leader ORF overlapped with the initiation codon of leuB was newly formed as a consequence of the insertion of a 0.5-kb BamHI fragment derived from the E. coli chromosome. The degree of expression from the plasmid was further improved by shortening the leader ORF to 36 bp without changing the overlapping portion, and the flanking sequence between the promoter and the leader ORF was removed. The expression in E. coli of the pfk1 gene (coding for phosphofructokinase) of T. thermophilus was improved by the construction of a structure similar to that which enhanced the expression of the leuB gene. Based on the results, a practical method for the overexpression of GC-rich genes in E. coli is proposed.

3-Isopropylmalate Dehydrogenase↗

PubMed1997

L-arginine inhibits smooth muscle cell proliferation of vein graft intimal thickness in hypercholesterolemic rabbits.

OBJECTIVE: The effect of the chronic administration of L-arginine on intimal thickness and the kinetics of smooth muscle cell proliferation in autovein grafts in hypercholesterolemic rabbits were examined. METHODS: Male rabbits were fed a 1% cholesterol diet (control group) and a 1% cholesterol diet supplemented by 2.25% L-arginine HCl in drinking water (arginine group). Each group underwent reversed autologous vein bypass grafting of the left common carotid artery using the left external jugular vein. At 2 or 4 weeks after operation, intimal cell proliferation was determined by 5-bromo-2'-deoxyuridine (BrdU) incorporation and intimal thickness of the graft was measured with an ocular cytometer. At 4 weeks after operation, endothelium-dependent responses were examined by isometric tension recording. RESULTS: At 4 weeks after operation, the level of plasma arginine and citrulline are significantly higher in the arginine group (n = 7), compared with the control (n = 7). Intimal thickness in the arginine group (n = 7) was significantly reduced, compared with that of the control (n = 7). At 2 weeks after operation, the BrdU labeling index of the control (n = 5) was significantly higher than that of the arginine group (n = 5). At 4 weeks after operation, ACh caused endothelium-dependent relaxation in the arginine group (n = 4), while in the control (n = 4), ACh did not relax. CONCLUSIONS: These results suggest that smooth muscle cell proliferation of the rabbit jugular vein grafts during hypercholesterolemia occurs at an early stage after graft implantation, prior to the development of intimal thickness. Intimal thickness of vein graft during hypercholesterolemia was reduced by chronic administration of dietary L-arginine, by inhibiting smooth muscle cell proliferation. The enhancement of NO production in the blood vessel wall may therefore be useful for preventing late graft failure.

Acetylcholine↗

PubMed1997

Halcurin, a polypeptide toxin from the sea anemone Halcurias sp., with a structural resemblance to type 1 and 2 toxins.

The aqueous extract of the sea anemone Halcurias sp. belonging to the suborder Endocoelantheae was found to be potently lethal to crabs, although it showed neither lethal activity in mice nor hemolytic activity. A polypeptide toxin (named halcurin) with a LD50 of 5.8 micrograms/kg against crabs was isolated by gel filtration on Sephadex G-50 and reverse-phase high-performance liquid chromatography on TSKgel ODS-120T. The complete amino acid sequence of halcurin comprising 47 residues was elucidated by sequence analysis of the native molecule and its enzymatic fragment. Comparison with the known sea anemone polypeptide toxins (types 1-3), which are all from members of the suborder Nynantheae, revealed a high sequence homology (49-74%) of halcurin with type 2 toxins. Also, halcurin has several residues conserved for only type 1 toxins. These results, together with the fact the Halcurias sp. is a more primitive species than members of Nynantheae, suggest that type 1 and 2 toxins have evolved from a common ancestor with a sequence more similar to halcurin.

Amino Acid Sequence↗

PubMed1997

Prognostic significance of serum anti-p53 antibody in patients with hepatocellular carcinoma.

BACKGROUND/AIMS: Abnormalities of the p53 gene can lead to the production of anti-p53 antibody in the serum of cancer patients. We evaluated the prognostic significance of anti-p53 antibody in 86 patients with hepatocellular carcinoma (HCC) in comparison with clinicopathological factors: age, sex, etiology, smoking and drinking habits, history of blood transfusion, presence of encephalopathy and ascites, Child classification, Pugh score, bilirubin, albumin, prothrombin time, indocyanine green retention time at 15 min (ICG), underlying liver disease, alpha-fetoprotein (AFP), tumor size, number of tumors, differentiation degree of HCC, presence of extrahepatic metastasis and therapy for HCC. METHODS: The serum anti-p53 antibody in 86 patients with HCC, 20 with chronic hepatitis (CH) and 20 with liver cirrhosis (LC) was measured by an enzyme-linked immunosorbent assay (ELISA). A single-strand conformation polymorphism-polymerase chain reaction (SSCP-PCR) analysis and loss of heterozygosity (LOH) study of the p53 gene were performed using 8 tissue samples of 8 HCC from four antibody-positive and four antibody-negative patients. The survival probabilities were assessed by the Kaplan-Meier technique, and a Cox regression analysis was used to identify the independent factors for prognosis. RESULTS: Anti-p53 antibody was positive in 32% (28 of 86) of the sera from patients with HCC, but in none of the 20 with CH and 20 with LC. p53 antibody positivity was associated with bilirubin and the number of tumors (p=0.027 and p=0.018, respectively). Overall survival was shorter in the HCC patients with p53 antibody than in those without p53 antibody (p<0.02). Bilirubin, p53 antibody, AFP and ICG were found to be significant prognostic factors by univariate analysis. A Cox multivariate analysis showed that bilirubin and p53 antibody were independent prognostic variables (p<0.0001 and p=0.003, respectively). In four antibody-positive patients, mutation and LOH of the p53 gene were detected in one patient and two patients, respectively. In contrast, only one of four antibody-negative patients exhibited LOH of the p53 gene. CONCLUSIONS: Serum anti-p53 antibody could be a useful prognostic factor in patients with HCC.

Adult↗

PubMed1997

Plasma concentrations of trazodone and m-chlorophenylpiperazine at steady state can be predicted from those after an initial dose of trazodone.

1. The authors studied the correlations between plasma concentrations of trazodone and mCPP at steady state and those after an initial dose of trazodone. 2. Fifteen depressed patients received trazodone 150 mg at bedtime for 3 weeks, and blood samplings were taken 12 h after the initial dose and 12 h after the last dose at each week. Plasma concentrations of trazodone and mCPP were measured by high-performance liquid chromatography. 3. Plasma concentration of mCPP, but not trazodone, was significantly higher at each week than after initial dosing. 4. For both trazodone and mCPP, significant linear relationships were found between plasma concentration after initial dosing and the average of 3 weeks' plasma concentrations. 5. The present study thus suggests that plasma concentrations of trazodone and mCPP at steady state can be predicted from those after an initial dose of trazodone.

Adult↗

PubMed1997

Possible interaction between cisapride and bromperidol.

1. The case of a schizophrenic patient taking bromperidol (18 mg/day), whose psychotic symptoms deteriorated markedly after addition of cisapride (7.5 mg/day), is presented. 2. Retrospective determination of drug concentrations revealed that plasma concentrations of bromperidol and its reduced metabolite were increased after cisapride addition. 3. The present study thus suggests that there is an interaction between cisapride and bromperidol.

Adult↗

PubMed1997

Isolation and amino acid sequences of two Kunitz-type protease inhibitors from the sea anemone Anthopleura aff. xanthogrammica.

Two protease inhibitors (AXPI-I and -II) were isolated from the sea anemone Anthopleura aff. xanthogrammica by a combination of acetone precipitation, gel filtration on Sephadex G-75, cation-exchange fast protein liquid chromatography (FPLC) on Mono S and reverse-phase HPLC on TSKgel ODS-120T. Both inhibitors are basic polypeptides, and their amino acid compositions are characterized by the presence of six half-Cys residues and the absence of Met and Trp. They are potently active against trypsin; inhibition of other serine proteases (alpha-chymotrypsin and elastase) is also displayed by only AXPI-I. However, the inhibitors show no affinity for metallo-proteases and cysteine proteases. Analyses of the N-terminal portion and enzymatic fragments established their complete amino acid sequences comprising 58 residues. The overall sequence homology and the conserved location of all half-Cys residues confirmed that the A. aff. xanthogrammica inhibitors belong to the Kunitz-type family.

Amino Acid Sequence↗

PubMed1997

Anticonvulsive and neuroprotective actions of a potent agonist (DCG-IV) for group II metabotropic glutamate receptors against intraventricular kainate in the rat.

Anticonvulsive and neuroprotective effects of (2S,1'R,2'R,3'R)-2-(2,3-dicarboxycyclopropyl) glycine (DCG-IV), a potent agonist for Group II metabotropic glutamate receptors, were examined in vivo against the excitotoxicity of kainic acid in the rat. Intraventricular injection of kainic acid (2 nmol) induced circling behavior and wet-dog shakes soon after injection, followed by episodes of limbic motor seizures at intervals of several minutes (sporadic limbic motor seizures). The frequency of sporadic limbic motor seizures gradually increased until seizures occurred incessantly (continuous limbic motor seizures). Intraventricular kainic acid also caused severe selective neuron damage in the hippocampal CA3 region, limbic lobe and medial geniculate body. Prolonged intraventricular infusion of DCG-IV (24-240 pmol/h) for 17 h before and 7 h after the application of kainic acid decreased the incidence of the continuous limbic motor seizures and the degree of neuronal damage in circumscribed brain areas. However, the behavioral changes observed immediately after the administration of kainic acid were unaffected by prolonged intraventricular infusion with DCG-IV (8-2400 pmol/h). Similarly, the occurrence of sporadic limbic motor seizures was only slightly reduced by the administration of DCG-IV (8-800 pmol/h). High doses of DCG-IV, greater than 800 pmol/h, afforded no protection against kainate-induced lesions; rather, the degradation of hippocampal CA1 pyramidal neurons was increased under such conditions. Single injections of DCG-IV (10-300 pmol/rat) in the lateral ventricle did not affect kainate neurotoxicity. Thus, prolonged infusion of DCG-IV showed a bell-shaped doso-response relationship with regard to protection against kainate-induced neurotoxicity.

Animals↗

PubMed1997

Enhancement of nitric oxide production after arterial reconstruction in patients with arteriosclerosis obliterans.

PURPOSE: Nitric oxide (NO) not only relaxes vascular smooth muscles, but it also reduces platelet adhesion and is itself a potent antiaggregatory substance. Experimental studies have shown that the release of NO is modulated by the blood flow. However, little clinical information is available about the effects of hemodynamic changes after arterial reconstruction on NO production. We therefore examined whether the plasma levels of nitrite (NO2-) and nitrate (NO3-) ions increased after arterial reconstruction in patients with arteriosclerosis obliterans (ASO). METHODS: Blood samples were obtained from the femoral artery in seven patients who underwent arterial reconstruction and seven healthy individuals (control). NO2- and NO3- levels were measured using high-performance liquid chromatography before the operation and 1 hour and 14 days after the operation. In addition, the mean femoral artery blood flow and ankle-brachial pressure index (ABI) were also measured using a duplex and Doppler velocimeter both before and after the operations. RESULTS: In the control subjects, the mean plasma NO2-, NO3-, and NOx (NO2- plus NO3-) levels in the femoral artery were 0.37 +/- 0.15 mumol/L, 45.6 +/- 10.8 mumol/L, and 46.0 +/- 10.9 mumol/L, respectively. Before the operation in the patients with ASO, the mean plasma NO3- (23.8 +/- 2.2 mumol/L) and NOx levels (24.0 +/- 2.3 mumol/L) were significantly lower than those in the control subjects, whereas the plasma NO2- levels (0.27 +/- 0.04 mumol/L) were comparable between the two groups. At 14 days after operation, the mean plasma NO3- and NOx levels in the femoral artery were significantly increased to 42.8 +/- 5.6 mumol/L and 43.4 +/- 5.6 mumol/L compared with those before the operation, whereas the mean plasma NO2- levels (0.50 +/- 0.05 mumol/L) changed significantly. The mean ABI and the mean flow rate before the operation were 0.32 +/- 0.07 and 344 +/- 145 ml/min, respectively. Both the ABI and the mean flow rate significantly increased to 1.04 +/- 0.06 and 627 +/- 141 ml/min after the operation. CONCLUSIONS: In patients who have ASO, the mean plasma level of NO is significantly lower than that of healthy individuals. In patients with ASO, the mean blood flow increased significantly after arterial reconstruction. This hemodynamic improvement may thus enhance NO production and may also help to maintain the patency of the bypass graft or native artery.

Aged↗

PubMed1997

Regional cortical dysplasia associated with suspected hypomelanosis of Ito.

A 15-year-old girl with epilepsy, whose skin lesions were reminiscent of hypomelanosis of Ito, is reported. She manifested hypopigmented linear streaks on her upper and lower limbs. Brain magnetic resonance imaging examinations demonstrated poor differentiation of cerebral gray and white matter of her left occipital lobe, with accompanying gliosis. This region also revealed narrowing of sulci, considered to be mass effect. In this region, almost continuous spike discharges were evident on electroencephalograms, and low-perfusion status was observed on single photon emission computed tomography at rest. She also manifested right lower homonymous quadrant anopsia, which may have its origin in the lesion detected, which appeared to be a migration disorder of neuroblasts in our patient, suggesting that the spectrum of hypomelanosis of Ito might be involved.

Adolescent↗

PubMed1997

Acceleration of impairment of endothelium-dependent responses under poor runoff conditions in canine autogenous vein grafts.

OBJECTIVES: To assess the effects of changes in shear stress on endothelium-dependent responses. MATERIALS AND METHODS: Autologous vein grafts were implanted in poor or normal distal runoff limbs of 10 mongrel dogs. Six weeks after grafting the vein grafts were removed, cut into rings, and suspended in organ chambers for isometric tension recording. RESULTS: The average value of intimal thickening was 110.7 +/- 45.2 microns in poor runoff limbs and 65.5 +/- 27.9 microns in control limbs, respectively. There was a significant difference between the two groups. Acetylcholine caused comparable endothelium-independent contractions in both groups. In the control group, adenosine diphosphate, thrombin and A23187 caused endothelium-dependent relaxations. In the poor runoff group, the endothelium-dependent relaxations caused by adenosine diphosphate and thrombin were impaired, while A23187 caused comparable endothelium-dependent relaxations. Direct relaxations in response to sodium nitroprusside were comparable between the two groups. CONCLUSIONS: This dysfunction of the endothelium under conditions of abnormal flow may accelerate intimal thickening of the vein graft and result in late graft failure.

Animals↗

PubMed1997

Screening of a mutant plasmid with high expression efficiency of GC-rich leuB gene of an extreme thermophile, Thermus thermophilus, in Escherichia coli.

A mutant plasmid with elevated expression efficiency of GC-rich Thermus thermophilus leuB gene was screened in Escherichia coli. A wild-type plasmid pHB2 carrying T. thermophilus leuB gene was introduced into leuB-deficient E. coli C600 cells. During successive cultures of the transformant in leucine-free medium, the original plasmid was spontaneously replaced by a mutant plasmid. The expression efficiency of the leuB gene on the mutant plasmid was 4.8-fold higher than that of the wild-type plasmid. Sequencing of the mutant plasmid revealed that the open reading frame (ORF1) in front of the leuB gene was shortened from 822 to 306 bp. Several expression vectors were constructed to investigate the effect of the length of ORF1, and the optimal length for the expression of the following leuB gene was determined. It was also shown that the stop codon of ORF1 should be overlapped with the initiation codon of leuB gene for the highest efficiency.

Amino Acid Sequence↗

PubMed1997

Increases in plasma concentration of m-chlorophenylpiperazine, but not trazodone, with low-dose haloperidol.

Our previous study suggested that cytochrome P4502D6 (CYP2D6) is involved in the metabolism of trazodone and its active metabolite, m-chlorophenylpiperazine (m-CPP). The purpose of this study was to examine the degrees of increase in plasma concentrations of trazodone and m-CPP induced by haloperidol, which is an inhibitor of CYP2D6. The subjects were nine depressed inpatients receiving trazodone at bedtime (150 mg in seven patients and 300 mg in two) for 2-19 weeks. Haloperidol at 4 mg/day was coadministered for 1 week, and blood samplings were taken before and after the coadministration. Contrary to our expectation, haloperidol did not significantly increase the mean plasma trazodone concentration (810 +/- 382 vs. 856 +/- 357 ng/ml). However, haloperidol significantly increased (p < 0.01) the mean plasma m-CPP concentration (78 +/- 31 vs. 92 +/- 34 ng/ml).

Adult↗

PubMed1997

No effect of the anticholinergic drugs trihexyphenidyl and biperiden on the plasma concentrations of bromperidol and its reduced metabolite.

Effects of the anticholinergic drugs trihexyphenidyl and biperiden on plasma concentrations of bromperidol and its reduced metabolite were studied. Subjects comprised 20 schizophrenic inpatients taking bromperidol, 6-18 mg/ day for 1-9 weeks. Patients were randomly allocated to one of two treatment sequences: trihexyphenidyl-biperiden (n = 12) or biperiden-trihexyphenidyl (n = 8). Each sequence consisted of two 2-week phases, with no washout period between the two phases. The daily dose of trihexyphenidyl was 8 mg and that of biperiden 6 mg. Plasma concentrations of bromperidol and reduced bromperidol were measured using high-performance liquid chromatography (HPLC). There was no significant difference in plasma bromperidol or reduced bromperidol concentrations among baseline, trihexyphenidyl and biperiden phases: 7.3 +/- 3.7 versus 7.2 +/- 4.1 versus 7.0 +/- 4.3 ng/ml and 2.0 +/- 2.1 versus 2.2 +/- 2.1 versus 1.9 +/- 2.0 ng/ml, respectively. The present study thus suggests that neither trihexyphenidyl nor biperiden affects plasma concentrations of bromperidol and its reduced metabolite.

Adult↗

PubMed1997

Increased plasma concentrations of bromperidol and its reduced metabolite with levomepromazine, but not with thioridazine.

Bromperidol is a close structural analog of haloperidol. The authors studied the effects of levomepromazine and thioridazine, which are frequently added to other neuroleptics as sedatives, on plasma concentrations of bromperidol and its reduced metabolite. The subjects were 26 inpatients with schizophrenia receiving bromperidol, 12 to 24 mg/day, for 1 to 19 weeks. In 10 cases, 50 mg levomepromazine per day and in nine cases, 50 mg thioridazine per day were coadministered for 1 week. In seven cases, both drugs were coadministered with > or = 2-week intervals. Plasma concentrations of bromperidol and reduced bromperidol were measured by a high-performance liquid chromatographic method. Levomepromazine (n = 17) significantly (p < 0.001) increased plasma concentrations of bromperidol (7.3 +/- 4.1 versus 10.2 +/- 4.8 ng/ml) and reduced bromperidol (1.8 +/- 1.4 versus 4.5 +/- 3.3 ng/ml). Thioridazine (n = 16) did not significantly change plasma concentrations of bromperidol (9.1 +/- 5.7 versus 8.6 +/- 5.5 ng/ml), while those of reduced bromperidol could not be measured because of interfering peaks. The current study suggests that levomepromazine, but not thioridazine, increases plasma concentrations of bromperidol and reduced bromperidol by inhibiting the metabolism of these compounds.

Adult↗