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Biomedical subjects

T Nishimura

Publications and source records attributed to T Nishimura.

At least 865 records · Page 48Linked to original sources
PubMed1991

Interaction of endocytotic vacuoles with the inner nuclear membrane in simian virus 40 entry into CV-1 cell nucleus.

The transfer of endocytosed simian virus 40 (SV40) to the nuclear position was investigated ultrastructurally using cationized ferritin (CF), ferritin labelled concanavalin A (Fer-Con A) and Con A as cell membrane markers. In the cells incubated with these markers and SV40 at 4 degrees C, and then chased for 2 h at 37 degrees C in serum-free medium, ferritin particles representing CF and/or Fer-Con A binding sites were found in vacuoles with SV40. The membrane of some vacuoles seemed to be in contact with the outer nuclear membrane. Several ferritin particles were located in the perinuclear cisterna and within the nucleoplasm, but not within the nuclear pores. In addition, there were vacuoles with ferritin particles and SV40 near the nuclear membrane, which looked like a single diaphragm with heterochromatins inside it. The outer nuclear and vacuole membranes were often obscure in the areas where the vacuole was very close to the diaphragm. In the case of cells incubated with CF, SV40 and Con A at 4 degrees C, chased for 2 h at 37 degrees C, and then reacted with horseradish peroxidase (HRP), HRP activity showing Con A-binding sites was also observed along the nuclear side of the inner nuclear membrane as well as in the perinuclear cisterna along the outer membrane. These results confirm that SV40-induced endocytotic vacuoles fuse with the outer nuclear membrane, and further indicate that some endocytotic vacuoles may well interact directly with the diaphragm, suggesting another path for migration of SV40 into CV-1 cell nuclei besides the path going through the process of fusion of the vacuole membrane with the outer nuclear membrane.

Animals↗
PubMed1991

Evaluation with Fourier analysis on radionuclide angiography of viable but stunned myocardium in patients with right ventricular myocardial infarction.

Stunned myocardium of right ventricle was studied by radionuclide angiography (RNA) and Thallium myocardial scintigraphy (TL) in 39 patients with inferior myocardial infarction with and without right ventricular myocardial infarction (RVMI). RNA was performed within 1 week of the onset (acute phase) and after 1 month, when exercise cardiac scintigraphy (EX-TL) was also performed. The ejection fraction (EF) of each ventricle calculated from RNA and the phase and amplitude evaluated visually and quantitatively by Fourier analysis were compared between the acute phase and 1 month after the onset of myocardial infarction. The degree of visualization of right ventricle was examined in EX-TL 1 month after the onset. (1) In RNA obtained in the acute myocardial infarction, abnormalities in the right ventricle (delayed phase or low amplitude image) were observed in 18 (46%) but not in 21 (54%) of the 39 patients (N group). Of those 18 patients, the abnormalities in the right ventricle alleviated in 11 (RVMI-A group) but persisted in 7 (RVMI-B group) in RNA obtained 1 month after the onset. (2) In the acute phase, the right ventricular ejection fraction (RVEF) was 39.4 +/- 10.4% in N group, 30.8 +/- 5.3% in RVMI-A group, and 29.6 +/- 8.9% in RVMI-B group, with significant differences between N group and the other two groups (P less than 0.05) but no significant difference between RVMI-A and RVMI-B groups. (3) After 1 month, RVEF was 40.1 +/- 10.1% in N group, 42.2 +/- 8.4% in RVMI-A group, and 32.2 +/- 9.8% in RVMI-B group, being improved in RVMI-A group and showing a significant difference as compared with RVMI-B group (p less than 0.05). (4) In EX-TL of RVMI-A group, the right ventricle was visible although the uptake of TL was reduced in the entire right ventricle. In RVMI-B group, only part of the right ventricular free wall was visible with defects in the other areas of right ventricle. The sign of RVMI showed improvements in many of the patients after the acute phase, and their condition was considered to have been so-called stunned myocardium, which is a complex of symptoms of reversible myocardial ischemia, rather than RVMI.

Aged↗
PubMed1991

Radionuclide assessment of stunned myocardium by alterations in perfusion, metabolism and function.

A method for the diagnosis of stunned myocardium has not yet been established, although it has been retrospectively demonstrated in patients after intracoronary thrombolysis, unstable angina, and coronary revascularization. In this study, radionuclide cardiac imaging was carried out to evaluate the existence of stunned myocardium. 1) Gated blood pool scanning was performed in patients undergoing intracoronary thrombolysis both at the time of reperfusion (Rp) and 10 days later. In the Rp less than 4 h group, about half of the initially abnormal segments showed complete improvement on quantitative wall motion analysis, which was more than in the Rp greater than 4 h and control groups. 2) In patients with acute myocardial ischemia, the correlation between thallium perfusion and regional wall motion was assessed semiquantitatively. In unstable angina, 5.8% of the ventricular wall segments showed dissociation between perfusion and wall motion (well-perfused asynergy). These segments had abnormal wall motion although perfusion was maintained, and were thought to be areas of stunned myocardium. 3) Fourteen dogs were studied using thallium and 123I-beta-methyliodophenyl pentadecanoic acid (BMIPP) fatty acid imaging to evaluate the relationship of perfusion to metabolism. In the reperfusion model, mismatching of the pattern of thallium and BMIPP uptake was observed. Reperfused myocardium probably has an increased triglyceride content, which is related to the degree of myocardial viability. In conclusion, stunned myocardium may be correctly diagnosed acutely on the basis of alterations in its perfusion, metabolism, and function by using radionuclide cardiac imaging.

Coronary Thrombosis↗
PubMed1991

Comparative study of computerized trapezoid rotation test and sinusoidal harmonic acceleration test.

By using the Contraves computerized rotary chair system, trapezoid rotation (TR) test and sinusoidal harmonic acceleration (SHA) test were performed on each subject on the same day. The results in 25 normal volunteers and 145 patients with peripheral vestibular disorders were as follows: 1) As regards directional preponderance, the results of two rotation tests agreed in 75.9% of all patients, but a discrepancy was found in the rest. Abnormality was detected by TR test in 57.2% of all patients, and, less frequently, in 45.5% by SHA test. 2) In normal subjects, the maximum slow phase velocity of nystagmus provoked by TR test was greater than that of nystagmus provoked by SHA test using angular acceleration of a magnitude comparable to that in TR test. 3) As to the detection of abnormal VOR gain, the results of two rotation tests agreed in 100% of patients with bilateral vestibular disorders. However, in patients with unilateral vestibular disorders, the detection rate was higher for SHA test than that for TR test.

Acceleration↗
PubMed1991

Studies on condensed-heterocyclic azolium cephalosporins. I. Synthesis and antibacterial activity of 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)- alkoxyiminoacetamido]-3-(imidazo[1,2-a]pyridinium-1-yl)methyl-3- cephem-4-carboxylates.

In our study of the structure-activity relationships of cephalosporins bearing quaternary ammonium groups at the 3 position, we postulated that delocalization of the azolium positive charge would lead to an expanded antibacterial spectrum and increased activity. Since quaternization of condensed-heterocyclic compounds such as imidazo[1,2-a]pyridine gives positive charge delocalization, 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)-alkoxyiminoacetamido] cephalosporin derivatives (1-53) bearing various (imidazo[1,2-a]pyridinium-1-yl)methyl moieties at the 3 position were prepared and their antibacterial activity was determined. As expected, these cephalosporins exhibited potent activity against both Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa. These results imply that imidazo[1,2-a]pyridine is a quite useful substituent for improving antibacterial activity and spectrum. The structure-activity studies revealed that a favorable substituent on the imidazo[1,2-a]pyridine is the cyano radical at the 6 position of the ring, and ethoxyimino or 1-carboxy-1-methylethoxyimino groups are suitable for the alkoxyimino substituent. Among the cephalosporins tested, 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)- ethoxyiminoacetamido]-3-(6-cyanoimidazo[1,2-a]pyridinium -1-yl)methyl-3-cephem-4-carboxylate (45) and 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)-(1- carboxy-1-methylethoxyiminoacetamido]-3-(6-cyanoimidazo[1,2- a] pyridinium-1-yl)methyl-3-cephem-4-carboxylate (49) showed good antibacterial activity.

Cephalosporins↗
PubMed1991

Studies on condensed-heterocyclic azolium cephalosporins. II. Synthesis and antibacterial activity of 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)-alkoxyiminoacetamido]-3-(condensed- heterocyclic azolium)methyl-3-cephem-4-carboxylates.

From our series of studies on cephalosporins bearing condensed-heterocyclic azolium methyl groups at the 3 position in the cephalosporin nucleus, we describe here the synthesis and antibacterial activity of 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)-alkoxyiminoacetamido]ceph alosporins containing imidazo[1,5-a]pyridinium, imidazo[1,2-b]pyridazinium, imidazo[1,2-a]pyrimidinium, imidazo[1,2-c]pyrimidinium, and pyrazolo[1,5-a]pyridinium methyl groups at the 3 position. Among the cephalosporins tested, 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3- (imidazo[1,5-a]pyridinium-2-yl) (1), (imidazo[1,2-b]pyridazinium-1-yl) (2), and (pyrazolo[1,5-a]-pyridinium-1-yl) (3)methyl-3-cephem-4-carboxylates showed potent antibacterial activity and broad antibacterial spectrum. The antibacterial activity of these cephalosporins (1 approximately 3) was superior to that of ceftazidime (CAZ). These results imply that the delocalization of the positive charge of the imidazo[1,5-a]pyridinium, pyrazolo[1,5-a]pyridinium and imidazo[1,2-b]pyridazinium groups leads to an expanded antibacterial spectrum and increased activity and that these condensed-heterocyclic compounds as well as imidazo[1,2-a]pyridine are effective moieties for improving antibacterial activity and spectrum.

Cephalosporins↗
PubMed1991

Structure-activity relationships of cadeguomycin analogs.

The relationship between the activity and the chemical structure of cadeguomycin (CDM, 7-carboxy-7-deazaguanosine) was studied with six analogs of CDM. Both activities of CDM, enhancing the incorporation of [3H]thymidine in K562 cells and potentiating the cytotoxicity of cytosine arabinoside for K562 cells, were significantly augmented by the replacement of the 7-carboxyl group with cyano (CDM-CN) or formyl (CDM-CHO), but they were not changed by the replacement with methyl. The activities were almost completely diminished by the replacement of ribose with arabinose, but the simultaneous replacement of carboxyl and ribose with formyl and arabinose showed higher activities than those of CDM. The replacement of 7-carboxy-7-deazaguanine with 7-carboxy-7-deazainosine markedly weakened the activity. CDM-CN and CDM-CHO at 0.2 micrograms/ml significantly potentiated the activity of cytosine arabinoside against MOLT-3 cells but CDM at 1 micrograms/ml did not. These results indicate that the ribose and guanine moieties in the CDM molecule are very important for its activity. Also replacing the carboxyl group at the C-7 position with cyano or formyl group is a useful way to strengthen the CDM activity. These compounds would effectively potentiate cytosine arabinoside against various kinds of tumor cells which CDM could not do.

Anti-Bacterial Agents↗
PubMed1991

Purification and properties of aminopeptidase C from chicken skeletal muscle.

Aminopeptidase C was purified from fresh chicken skeletal muscle by ammonium sulfate fractionation, and by successive chromatography on DEAE-cellulose, Ultrogel AcA 34, DEAE-cellulose again, and an alanine AH-Sepharose 4B affinity column twice. The purified enzyme migrated as a single band by SDS-PAGE. Aminopeptidase C was purified about 300-fold over the crude extract with a yield of 0.6%. The molecular weight of this enzyme was found to be 185,000 by gel filtration in a Sepharose 6B column and 92,000 by SDS-PAGE. The optimum pH for the hydrolysis of L-leucine beta-naphthylamide was 6.0-7.0, the enzyme being stable in the range of pH 6.5-8.0. The activity of this enzyme was strongly inhibited by EDTA and puromycin, and was high against the beta-naphthylamide derivatives of Lys, Leu, Ala and Met. The enzyme was more active towards tri- and tetrapeptides than towards dipeptides.

Amino Acid Sequence↗
PubMed1991

Pharmacological properties of the new non-steroidal anti-inflammatory agent etodolac.

The anti-inflammatory, analgesic, antipyretic and ulcerogenic activities of etodolac (CAS 41340-25-4), a new nonsteroidal anti-inflammatory agent, were compared with those of indometacin and other anti-inflammatory drugs in experimental animals. Etodolac had a remarkable anti-inflammatory effect in various experimental models: ultraviolet erythema, carrageenin-induced edema and swelling of adjuvant arthritis. In these models, the effective dose of etodolac was several fold that of indometacin. Etodolac inhibited prostaglandin E2 formation in a concentration-dependent manner, and its inhibitory potency was about 1/5 of that of indometacin. Etodolac also caused marked inhibition of granuloma formation and leucocyte functions such as chemotaxis, lysosomal enzyme release and active oxygen generation. These effects of etodolac were observed at similar doses of indometacin. Etodolac suppressed inflammatory pain but not non-inflammatory pain, and had an antipyretic effect but did not lower normal rectal temperature. Etodolac had no effect on delayed hypersensitivity reactions and was much less ulcerogenic than indometacin. These results indicate that etodolac is a low ulcerogenic anti-inflammatory agent with suppressing activities on leucocyte functions to the same extent as indometacin and prostaglandin biosynthesis.

Animals↗
PubMed1991

[Primary cardiac tumor with singular findings on cardiac radionuclide scintigraphy].

We encountered a primary cardiac tumor originated from the right atrium or pericardium with singular findings on cardiac radionuclide scintigraphy. The patient was 43-year-old female who showed asymptomatic cardiomegaly and abnormal cardiac silhouette by chest X-ray. First pass radionuclide angiography using Tc-99m pertechnetate revealed the abnormal stain filled from the stem of ascending aorta inner and outer portion of the right atrium. Selective angiography showed that the main feeding artery of the tumor was right coronary artery and right internal mammary artery. The pathological diagnosis of the surgically resected specimen was angiosarcoma. It was suggested that detail evaluation of first pass radionuclide angiography give us a useful clinical information linked the feeding artery of cardiac tumor in this case.

Adult↗
PubMed1991

Enhancement of activities of anti-tumor drugs by dipyridamole against multidrug-resistant human hepatoma PLC/PRF/5 cells.

Dipyridamole (DPM) at 10 microM enhanced the cytotoxicity of anti-tumor drugs, which were associated with multidrug resistance, more in multidrug-resistant human hepatoma PLC/PRF/5 cells (PLC/COL) than in its parental cells (PLC/S). DPM increased, dose-dependently, the intracellular accumulation of [3H]vinblastine in PLC/COL. However, the effect was immediately diminished by its removal from the medium, indicating that DPM needed to be present together with the anti-tumor drugs to enhance the intracellular accumulation of the drugs. DPM inhibited the efflux of [3H]vinblastine from the PLC/COL cells, the binding of [3H]vinblastine to membrane vesicles of PLC/COL, and the binding of [3H]azidopine to P-glycoprotein in the plasma membrane of PLC/COL. Apparently DPM binds to P-glycoprotein and inhibits active efflux. [14C]labeled DPM was quickly incorporated into the cells and the cellular level of [14C]DPM reached a plateau after 5 min. It was slightly higher in PLC/S than in PLC/COL. The cellular [14C]DPM quickly disappeared after its removal from the medium. These results indicate that DPM binds quickly but reversibly to various kinds of cellular proteins including P-glycoprotein and inhibits active efflux of some anti-tumor drugs in multi-drug-resistant tumor cells, resulting in the enhancement of the activities of these drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Mechanism of anti-inflammatory action of etodolac.

The effect of etodolac (CAS 41340-25-4) on the inflammatory reactions induced by histamine and bradykinin was compared with that of indomethacin and other nonsteroidal anti-inflammatory drugs. Etodolac (50 mg/kg p.o.), indomethacin (20 mg/kg p.o.), diclofenac Na (20 mg/kg p.o.) and acetylsalicylic acid (200 mg/kg p.o.) had no effect on the increase of vascular permeability induced by histamine or bradykinin and on passive cutaneous anaphylaxis in rats. Etodolac (5, 10 and 20 mg/kg p.o.) suppressed concanavalin A-induced paw edema in rats. Etodolac (10 mg/kg p.o.) and bromelain (10 mg/kg i.v.) significantly suppressed the heat-induced elevation of bradykinin in perfusates of rat paws, but indomethacin (20 mg/kg p.o.) and diclofenac Na (20 mg/kg p.o.) did not. Etodolac inhibited bradykinin-forming enzyme activity in a concentration-dependent manner (IC50 = 1.5 x 10[-4) mol/l). These results suggest that etodolac is a unique nonsteroidal anti-inflammatory drug which can inhibit bradykinin formation, unlike indomethacin or diclofenac Na.

Animals↗
PubMed1991

Automated measurement of amylase isoenzymes by a double kinetic assay with "blocked" beta-2-chloro-4-nitrophenyl maltopentaoside as substrate and with wheat germ inhibitor.

We evaluated the enzymic mechanism by which 3-keto butylidene-beta-2-chloro-4-nitrophenyl maltopentaoside (3KB-G5-CNP) serves as a substrate for serum pancreatic (p-) and salivary (s-) amylases. In aliquots of the reaction mixture, three kinds of beta-2-chloro-4-nitrophenyl oligosaccharides (glucose, maltoside, and maltotrioside) were separated from the substrate by high-performance liquid chromatography. Both isoenzymes behaved nearly identically and produced almost the same products. We automated a double kinetic procedure for determining total (t-) and p-amylase with use of a selective inhibitor from wheat germ in a single channel on the Hitachi 7050 analyzer. Within- and between-run CVs were, respectively, 0.5% and 1.7% for t-amylase (240 U/L), and 0.7% and 2.3% for p-amylase (230 U/L). The test results varied linearly with concentrations up to approximately 2000 U/L for t- and p-amylase activities. p/s ratios varied from 0.2 to 5.0. Results correlated well with those obtained by the monoclonal inhibition method (r = 0.992).

Amylases↗
PubMed1991

[A comparative clinical study of adjuvant chemotherapy of tumors in the head and neck areas by means of HCFU].

In order to evaluate the efficacy of HCFU as an adjuvant chemotherapy agent for squamous cell carcinoma of the head and neck areas, a randomized comparative study was performed with cooperative facilities. 191 patients who had undergone radical therapy were randomly assigned to the following two groups: Group A was the control group, which underwent radical therapy only, and Group B was a group which received long-term HCFU administration (300-600 mg/day x 12 weeks or more). In the comparison of non-recurrence rate in both groups, Group B had better results among patients who were at the advanced clinical stages such as N1 through N3, Stage II (p = 0.0583) and Stage III (p = 0.0970). The adverse reactions to HCFU included pollakiuria, feverishness, and digestive symptoms, but these were mild and the recovery was possible.

Adult↗