Biomedical subjects

J Kojima

Publications and source records attributed to J Kojima.

At least 37 records · Page 2Linked to original sources

PubMed2000

Effectiveness of interferon therapy for reducing the incidence of hepatocellular carcinoma among patients with type C chronic hepatitis.

STUDY PURPOSE: To evaluate the effect of interferon treatment for reducing the incidence of hepatocellular carcinoma among patients with type C chronic hepatitis. METHODS: Retrospective cohort study was conducted on 923 patients with type C chronic hepatitis, who were identified through databases of Osaka Medical Center for Cancer and Cardiovascular Diseases. Two hundred and twenty-four of those had undergone interferon treatment, while the other 699 patients had not. Kaplan-Meier method and the proportional hazards model were used for statistical analysis. RESULTS: Five-years' cumulative incidence of hepatocellular carcinoma was 2.2% among the interferon treated patients, while 9.5% among the interferon untreated. Difference between the 2 curves of the cumulative incidence was statistically significant (p=0.0015). After adjustment for possible confounders, hazard rate ratio of hepatocellular carcinoma was 0.31 in the interferon treated group, significantly lower than that in the untreated (p=0.015). Hazard rate ratio for death from causes other than hepatocellular carcinoma and liver diseases was also lower among the interferon treated group than that among the untreated, although not significant. CONCLUSIONS: Interferon treatment is suggested to reduce the risk of hepatocellular carcinoma among patients with type C chronic hepatitis, and not to increase the risk for death from causes other than hepatocellular carcinoma and liver diseases.

Antiviral Agents↗

PubMed2000

Acute and subacute toxicities of theophylline are directly reflected by its plasma concentration in dogs.

The purpose of this study was to evaluate the relationship between acute and subacute toxicity and blood levels of theophylline in dogs. Theophylline was administered intravenously into dogs once (at doses of 50, 100 and 150 mg/kg) or for 4 weeks (at doses of 20, 35 and 70 mg/kg/day). In the single dose toxicity study, by increasing the dose of theophylline, plasma concentration increased and the severity of toxic symptoms were intensified. After a single dosing of theophylline, accentuated heart rate and vomiting were observed at a concentration of more than 67 micrograms/ml, and excitement, spasm and hyperpnea were observed at more than 130 micrograms/ml. Animals died after tonic convulsion at 180 micrograms/ml. In the repeated dose toxicity study, the plasma concentration of theophylline increased dependent on dosage, and was not affected by repeated dosing. Even under these conditions, the toxic symptoms were quite similar to those of the single dose, except for an additional decrease in movement, body weight reduction and myocardial lesion. These present results suggest that the severity of theophylline toxicity is dependent on its plasma concentrations rather than accumulated dosages. The blood concentration of theophylline-treated patients should be maintained within the therapeutic range in order to diminish risk.

Animals↗

PubMed2000

Pharmacokinetic study of theophylline in dogs after intravenous administration with and without ethylenediamine.

Aminophylline (ethylenediamine salt of theophylline) and Theodrip, a new formulation of theophylline developed by Nikken Chemicals, are drugs for the treatment of acute bronchial asthma in injectable form. The present study was conducted using dogs to first confirm the bioequivalence of the two injectable forms containing theophylline and aminophylline and to secondly clarify the influence of the rate of venous infusion on the pharmacokinetics of theophylline in plasma. The following results were obtained: 1) Pharmacokinetic parameters of plasma theophylline after an intravenous bolus injection were close to those after the dosing of aminophylline in dogs by a crossover method. Thus, the 95% confidence limits of mean value differences of Cmax, t1/2 and AUC between the two injection forms were in the range of -3.16-4.28%, -6.19-7.28% and -7.23-5.28%, respectively. These results indicate the bioequivalence between theophylline and aminophylline in dogs from a pharmacokinetic point of view as well as the lack of influence of ethylenediamine on the pharmacokinetics of theophylline. 2) After the intravenous bolus injection (30 sec) and the 15-min constant rate infusion of theophylline to dogs, the plasma concentrations of theophylline were 27.37 +/- 3.67 micrograms/ml and 18.34 +/- 2.32 micrograms/ml immediately after the completion of administration, respectively. It is notable that in humans the former concentration level has been observed to frequently cause adverse effects, whereas the latter was in the safe range. Consequently, the 15-min constant rate infusion did not result in the rapid increase in the plasma theophylline concentrations and was superior to the bolus injection from the viewpoint of maintaining the safety plasma concentrations. In conclusion, to avoid hypersensitivity due to ethylenediamine and the adverse effects caused by high plasma concentrations of theophylline, it was considered that constant rate infusion of theophylline to the venous is preferable in the clinical setting.

Aminophylline↗

PubMed1999

Exogenous microglia enter the brain and migrate into ischaemic hippocampal lesions.

We compared migration of systemically injected microglia into normal brain vs. ischaemic brain using a model of ischaemic hippocampal lesion. Microglia were labeled by a fluorescent dye using our standard phagocytosis procedure of microscopic particles and then injected intra-arterially into Mongolian gerbils subjected to ischaemia reperfusion neuronal injury. Delayed death of pyramidal neurons was confirmed by conventional histological analysis and dUTP nick end labeling (TUNEL) method. Clusters of dye-tagged cells migrating into the hippocampal ischaemic lesions were confirmed histochemically to be microglia. Since peripherally injected microglia exhibit specific affinity for ischaemic brain lesions and does not exacerbate ischaemic neuronal injury in the present model, we suggest that microglia may have a potential to be used as a piggy-back ride to deliver therapeutic genes and/or drugs for CNS repair following transitory global ischaemic insult.

Animals↗

PubMed1999

Simultaneous determination of NK-104 and its lactone in biological samples by column-switching high-performance liquid chromatography with ultraviolet detection.

A simple and sensitive column-switching HPLC method has been developed for the simultaneous determination of NK-104 (HMG-CoA reductase inhibitor) and its lactone in human and dog plasma. Plasma sample was extracted with methyl tert-butyl ether and then the extract was subjected to methylation with diazomethane to prevent the mutual conversion between NK-104 and its lactone. The extract was injected into the column-switching HPLC system. The calibration curves of NK-104 and NK-104 lactone were linear over the ranges 0.5 to 100 ng/ml for human plasma samples and 0.5 to 500 ng/ml for dog plasma, respectively. The intra-day and inter-day C.V. values of these analytes were less than 13.3%. The intra-day and inter-day accuracies of these analytes were between -14.0 and 6.5%. The proposed method has been applied to plasma samples obtained after oral administration of a single 2 mg dose of NK-104 to volunteers.

Animals↗

PubMed1999

Reduced expression of the alphabeta T-cell antigen receptor by alveolar T-cells.

A previous study revealed that reduced expression (modulation) of the CD3 antigen is a common characteristic of alveolar T-cells in health and disease. As CD3 molecules are noncovalently bound to T-cell antigen receptors (TCR), it was hypothesized that modulation of TCR was also a feature of alveolar T-cells. To demonstrate this, lymphocytes from bronchoalveolar lavage fluid were stained with an anti-alphabeta TCR antibody and analysed by flow cytometry. The expression of alphabeta TCR by alveolar T-cells was evaluated by calculating mean fluorescence intensity (MFI) and was compared with alphabeta TCR expression by autologous blood T-cells. As anticipated from a previous study, modulation of TCR was observed not only in healthy volunteers but also in patients with pulmonary sarcoidosis, other pulmonary diseases, and nonpulmonary diseases. There were no significant differences in MFI of alveolar T-cells among the study groups. The degree of modulation assessed by the difference of MFI between blood and alveolar T-cells was greater for CD4+ cells than for CD8+ cells owing to the higher MFI of CD4+ blood T-cells. Coculture of alveolar macrophages with blood T-cells in vitro induced partial modulation of TCR. These results demonstrate the ubiquity of modulation of T-cell receptors on alveolar T-cells and suggest, in contrast to a previous report by other investigators that it is caused by some nonantigenic mechanism possibly inherent in the alveolar milieu. The implications of this phenomenon in in vivo immune responses of the lung need to be examined.

Adult↗

PubMed1999

Identification of metabolites of NK-104, an HMG-CoA reductase inhibitor, in rat, rabbit and dog bile.

NK-104 is an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase with a very potent lipid-lowering effect. Biotransformation profiles of NK-104 in bile from rat, rabbit and dog given an intravenous infusion of NK-104 were investigated. Structural assignment was made by liquid chromatography (LC)-mass spectrometry (MS)-MS and proton NMR analyses. The predominant component was intact NK-104 in all the animals. At least eight other metabolites were present in rat, four in rabbit, and 10 in dog. These bile metabolites were purified and isolated by preparative HPLC. Biotransformation pathways elucidated for NK-104 were as follows: (a) lactonization ; (b) beta-oxidation of the side-chain; (c) hydroxylation of the quinoline ring; (d) conjugation with Beta-glucuronic acid and taurine. Beta-oxidative degradation of the side-chain in the case of other HMG-CoA reductase inhibitors is necessary for epimerization of the hydroxy group which has an R-configuration. However, M-16, glucuronide of the ketolactone derivative, was obtained as a key metabolite suggesting another beta-oxidation pathway for the side-chain.

Animals↗

PubMed1998

Effects of NIK-247 and tacrine on muscarinic receptor subtypes in rats.

1. The purpose of this study was to compare the effect of NIK-247 on muscarinic receptor subtypes with that of tacrine (THA) in rats. 2. NIK-247 and tacrine dose dependently inhibited the binding of [3H]pirenzepine (M1), [3H]AF-DX 384 (M2), and [3H]4-DAMP (M3). The IC50 values for NIK-247 were 4.4 x 10(-6) M, 1.1 x 10(-5) M, and 1.5 x 10(-5) M, respectively, whereas those for tacrine were 5.8 x 10(-7) M, 2.0 x 10(-6) M, and 5.8 x 10(-6) M, respectively. 3. Gpp[NH]p, a GTP analogue, slightly shifted the curve of displacement of [3H]AF-DX. 384 binding for NIK-247 to the right. However, Gpp[NH]p did not shift the curve of displacement of [3H]pirenzepine and [3H]4-DAMP binding to the right. 4. NIK-247 moderately decreased the rate of beating in right atrial preparations, but did not decrease it below 50% of control level. 5. These findings indicate that NIK-247 is an M1 antagonist, M2 partial agonist, and M3 antagonist.

Aminoquinolines↗

PubMed1998

NIK-247 induces long-term potentiation of synaptic transmission in the CA1 region of rat hippocampal slices through M2 muscarinic receptors.

1. The purpose of this study was to examine whether NIK-247 can, by itself, induce long-lasting changes in synaptic efficacy in the hippocampus. Population spikes evoked by electrical stimulation of the stratum radiatum were recorded in the pyramidal cell layer of the CA1 region of the isolated hippocampus. 2. NIK-247 at 1 x 10(-7) - 1 x 10(-5) M dose dependently increased the amplitude of these spikes. The increase in population spikes by NIK-247 outlasted, for 2 hr, its presence. In addition, the increase in population spikes recovered to 2 hr after washout of NIK-247. Therefore, it was concluded that NIK-247 induced long-term potentiation (LTP) by itself. However, tacrine and physostigmine at 1 x 10(-7) - 1 x 10(-5) M did not increase the amplitude of population spikes and did not induce LTP by themselves. 3. The increase in amplitude of population spikes induced by NIK-247 was completely blocked sensitively by atropine (IC50 = 4.3 x 10(-8)M) but insensitively by pirenzepine (IC50 = 9.1 x 10(-7) M). Carbachol also increased the amplitude of population spikes in the presence of pirenzepine. 4. These findings indicate that the LTP induced by NIK-247 is due to its M2 muscarinic agonistic effect in the CA1 region of the rat hippocampus. It is expected that NIK-247 may be useful for the treatment of Alzheimer disease.

(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethy↗

PubMed1998

Expression of RANTES by bronchoalveolar lavage cells in nonsmoking patients with interstitial lung diseases.

Emphasis has recently been placed on the roles of chemotactic cytokines called chemokines to explain the accumulation of inflammatory cells in the lung that may precede or accompany pulmonary fibrosis in interstitial lung diseases. We hypothesized that RANTES, a member of the C-C chemokines, is one such chemokine. Bronchoalveolar lavage was done in 20 patients with sarcoidosis, 10 patients with interstitial pneumonia associated with collagen vascular disease (CVD-IP), 10 patients with idiopathic pulmonary fibrosis (IPF), and eight healthy volunteers (HV), all of whom were never-smokers. We semiquantitated the spontaneous RANTES mRNA expression by a competitive reverse transcription-polymerase chain reaction (RT-PCR) technique, and measured the levels of RANTES protein by enzyme-linked immunosorbent assay. In all disease groups the expression of RANTES mRNA by bronchoalveolar lavage fluid (BALF) cells and the levels of RANTES protein in BALF were significantly increased compared with those in HV. Patients with sarcoidosis and CVD-IP had a significant positive correlation between the expression of RANTES mRNA by BALF cells and BALF lymphocytosis. The amounts of RANTES mRNA expressed by peripheral blood mononuclear cells and the levels of RANTES protein in serum did not differ among all study groups. Our study demonstrates the adaptability of a semiquantitative RT-PCR method for determining cytokine mRNA expression in vivo. Our results suggest that RANTES may be one of the chemokines that are involved in the mechanism for the accumulation of inflammatory cells in the lung of some distinct interstitial lung diseases.

Bronchoalveolar Lavage↗

PubMed1998

Ipidacrine (NIK-247), a novel antidementia, rapidly enters the brain and improves scopolamine-induced amnesia in rats during the Morris water maze task.

The effects of single and repeated administrations of ipidacrine (NIK-247, 9-amino-2, 3, 5, 6, 7, 8-hexahydro-1H-cyclopenta [b] quinoline monohydrochloride monohydrate) on scopolamine-induced spatial learning deficit were investigated in rats using the Morris water maze task. A single oral administration of ipidacrine (0.3 and 1 mg/kg) reduced the increased total latency induced by scopolamine in this task. The repeated administration of ipidacrine (1 mg/kg) of once a day for 5 successive days reduced the increased total latency induced by scopolamine to the levels of the saline-treated control rats in this task. In this pharmaco-kinetic study, ipidacrine was rapidly taken up into the brain within 5 min. Moreover, higher drug levels were observed mainly in the cortex and hippocampus, which both play important roles in learning and memory. Thus, a previous study together with this investigation indicate that ipidacrine improves amnesia which consists of the impairment of the working and reference memory in various animal models, suggesting that ipidacrine is a useful candidate for the therapy of patients with Alzheimer's disease.

Aminoquinolines↗

PubMed1997

Excitotoxic lesions of the pedunculopontine tegmental nucleus produce contralateral hemiparkinsonism in the monkey.

Dopaminergic nigrostriatal neurons, degeneration of which causes Parkinson's disease, are known to receive excitatory input almost exclusively from the pedunculopontine tegmental nucleus (PPN). We report here that excitotoxic lesions of the PPN produce abnormal motor signs relevant to hemiparkinsonism in the macaque monkey. Under the guidance of extracellular unit recordings, the electrophysiologically identified PPN was injected unilaterally with kainic acid. These PPN-lesioned monkeys exhibited mild to moderate levels of flexed posture and hypokinesia in the upper and lower limbs contralateral to the lesion. In most of the monkeys, such pathophysiological events were gradually improved and became stationary in 1-2 weeks. The hemiparkinsonian symptoms observed after PPN destruction might be ascribed to a decrease in nigrostriatal neuron activity due to excitatory input ablation.

Animals↗

PubMed1997

Effects of NIK-247 on cholinesterase and scopolamine-induced amnesia.

The effects of NIK-247 on cholinesterase, scopolamine-induced amnesia and spontaneous movement were examined and compared with those of the well-known cholinesterase inhibitors tacrine and E-2020. NIK-247, tacrine and E-2020 all strongly inhibited acetylcholinesterase (AChE) in human red blood cells (IC50s = 1.0 x 10(-6), 2.9 x 10(-7) and 3.7 x 10(-8) M, respectively). In addition, NIK-247 and tacrine, but not E-2020, strongly inhibited butyrylcholinestrase (BuChE) in human serum. All three drugs produced mixed inhibition of AChE activity. Moreover, the inhibitory effect of NIK-247 on AChE was reversible. All compounds at 0.1-1 mg/kg p.o. significantly improved the amnesia induced by scopolamine (0.5 mg/kg s.c.) in rats performing a passive avoidance task. The three compounds at 1 and 3 mg/kg p.o. did not significantly decrease spontaneous movement by rats. These findings suggest that NIK-247 at a low dose (0.1-1 mg/kg p.o.) improves scopolamine-induced amnesia but does not affect spontaneous movement. The findings suggest that NIK-247 may be a useful drug for the treatment of Alzheimer's disease.

Acetylcholinesterase↗

PubMed1997

Pharmacological profile of a novel synthetic inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase.

Pharmacological properties of NK-104 ((+)-monocalcium bis¿(3R,5S,6E)-7-[2-cyclopropyl-4-(4-fluorophenyl)-3-quinolyl++ +]-3,5-dihydroxy-6- heptenoate¿, CAS 147526-32-7), a novel synthetic inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, were investigated. The kinetic study, using rat liver microsomal HMG-CoA reductase, revealed that NK-104 is a competitive inhibitor of HMG-CoA reductase with a Ki of 1.7 nmol/l. To examine the inhibitory effect on sterol synthesis in vivo, de novo synthesis of sterols from [14C]acetate 3 h after oral administration of NK-104 was measured in rats. NK-104 showed marked inhibition in liver (ED50 0.13 mg/kg) and in ileum (ED50 0.20 mg/kg), but much weaker in the other tissues. The inhibitory effect of NK-104 on liver sterol synthesis lasted over 6 h, while that of pravastatin and simvastatin disappeared 6 h after administration of the drugs twice the ED50s. Due to induction of HMG-CoA reductase, initial suppression of hepatic sterol synthesis by pravastatin and simvastatin was compensated, and the cumulative change in hepatic sterol synthesis during 12 h after drug administration was remarkably negative only with long-acting NK-104. Hypolipidemic effects of NK-104 (0.03, 0.1, 0.3 and 1 mg/kg p.o. for 2 weeks) were examined in beagle dogs. NK-104 reduced plasma total cholesterol dose-dependently (13.1, 18.5 and 20.2% at doses of 0.1, 0.3 and 1 mg/kg, respectively), and also plasma triglycerides by 0.1 mg/kg or more. Pravastatin (1 and 3 mg/kg) and simvastatin (3 mg/kg) lowered plasma total cholesterol (14.0, 15.4 and 17.4%, respectively), but did not significantly affect plasma triglyceride levels. These results indicate that NK-104 is a potent, liver-selective, long-acting HMG-CoA reductase inhibitor with a high cholesterol- and triglyceride-lowering potency.

Animals↗

PubMed1997

Activated protein C resistance assay as a screening test for thromboembolic disposition.

An activated partial thromboplastin time (APTT) based method was developed to determine the anticoagulant response in patient plasma to added purified activated protein C (APC). On the other hand, Bertina et al. (1994) reported that one point mutation of amino acid 506 in the factor V was observed in such APC resistance patients. APC resistance for blood samples with known abnormal findings on the coagulation test also may be determined. Coagmaster II for the APTT assay system (Sankyo, Tokyo, Japan) was employed. The APC resistance assay system was a useful reagent as a screening test for lupus anticoagulant (LA), in addition to APC resistance.

Calcium Chloride↗

PubMed1996

Tonic activity during visuo-oculomotor behavior in the monkey superior colliculus.

The purpose of this study was to examine whether the superior colliculus is involved in intermediary cognitive processes such as memory, movement preparation, and peripheral attention. To answer this question, we recorded single cell activities in the superior colliculus of monkeys trained to perform a series of visuo-oculomotor tasks: delayed saccade task (SACD), saccade task with overlap target (SACO), and attention task (ATT). We recorded 141 neurons showing tonic activities related to the tasks. Depending on the predominance of the activities among the three tasks, we classified the tonic neurons into four types: (1) visuomotor (greater activity in SACO), (2) mnemonic motor (SACD dominant), (3) attention (ATT), and (4) nonspecific. Among 108 neurons recorded in the intermediate layer, 13 were of a visuomotor type, 15 were of a mnemonic motor type, and 13 were of an attention type. The other 67 neurons were of a non-specific type. Of the 33 neurons in the superficial layer, many neurons were of the non-specific type. These results suggested that the tonic activities in the superior colliculus are related to memory of the target location, preparation of saccades and peripheral attention.

Animals↗

PubMed1996

Deletion polymorphism in the angiotensin I converting enzyme (ACE) gene as a genetic risk factor for sarcoidosis.

BACKGROUND: Genetic control of serum angiotensin I converting enzyme (SACE) levels has been suggested. A study was undertaken to elucidate the role of this polymorphism in sarcoidosis. METHODS: Three hundred and forty one unrelated healthy controls and 103 consecutive patients with sarcoidosis participated in the study. SACE levels and an insertion/deletion (I/D) polymorphism in intron 16 of the ACE gene were studied in each subject and new reference intervals for SACE activity for each genotype were determined. The difference in genotype and allele frequencies between controls and patients was analysed and odds ratios were calculated to estimate the relative risk. RESULTS: A significant association was seen between ACE gene polymorphism and SACE levels in both patients and controls. The new reference intervals for each genotype discriminated abnormal SACE levels in patients more accurately, especially those with genotype II. In women the frequencies of allele I were 0.68 (allele D 0.32) in controls and 0.58 (allele D 0.42) in patients, and the difference between the two female groups was significant (p < 0.05). Thus, an excess of genotype ID or DD was observed in female patients (odds ratio 2.18; 95% confidence interval 1.18 to 4.01; p = 0.01). CONCLUSIONS: These findings suggest that ACE gene polymorphism is associated with SACE levels in both patients with sarcoidosis and controls. ACE gene polymorphism should be further evaluated as a candidate marker for an increased risk of sarcoidosis.

Adult↗

PubMed1996

[Quick radioimmunoassay for plasma immunoreactive gastrin--application for localizing occult gastrinoma(s) during operation].

A rapid method for determining gastrin, quick gastrin, has been developed. Separation/washing procedure has been improved and can be completed within three minutes. It required only 48 minutes for the assay of 22 blood samples. Quick gastrin is a RIA that uses magnetic particles. On magnetic particles, a goat anti-rabbit IgG antibody is bound covalently. An anti-human gastrin rabbit antibody is bound to an anti-rabbit IgG antibody. Assay is started by adding the magnetic particles to a mixture of sample and 125I-gastrin. Following 30 minute incubation at 37 degrees C, the particles are sedimented in a magnetic field and washed. The gastrin content of the sample is then quantitated by counting radioactivity of the particles. Incomplete equilibration of antigen-antibody reaction is corrected using standard solution prepared from charcoal treated plasma. The immunoreactive gastrin values by quick gastrin correlated well with those by a commercial assay kit (Gammadab RIA kit; y = 1.01 x +4.3, r = 0.99). When compared to a reported conventional rapid assay, quick gastrin is easier and more accurate. Quick gastrin is sensitive enough to use for intra-operative determination of gastrin. We applied quick gastrin to the samples obtained from intra-operative secretin test in a gastrinoma patient. Twofold increases in gastrin after injection of secretin clearly indicated the existence of occult gastrinomas in her pancreas. When gastrin was assayed with the conventional rapid method, the increase in gastrin was less and did not reach the criteria for existence of gastrinoma.

Adult↗