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T Toyoda

Publications and source records attributed to T Toyoda.

At least 127 records · Page 7Linked to original sources
PubMed1994

Renin inhibitor: transport mechanism in rat small intestinal brush-border membrane vesicles.

The transport characteristics of the renin inhibitor ((3S,4S)-4-[N-morpholinoacetyl-(1-naphthyl)-L-alanyl-N-methyl-(4-t hiazolyl)-L- alanyl]amino-3-hydroxy-5-cyclohexyl-1-(4-pyridyl)-1-pentanone; CH3-18) in rat small intestinal brush-border membrane vesicles (BBMV) were examined by a rapid filtration technique. The uptake of CH3-18 was markedly stimulated by an inwardly directed H+ gradient (pH 7.5 inside, pH 5.5 outside) and showed an uphill transport. It was competitively inhibited by tripeptides and tetrapeptides, but not by amino acids or dipeptides. A countertransport effect on the uptake of CH3-18 was observed in the vesicle preloaded with a tripeptide. Effects of the fragments of several renin inhibitors were evaluated by their inhibitory and countertransport effects on the uptake of CH3-18. The morpholino group at the N-terminal was found to be important for the uptake of CH3-18.

Amino Acid Sequence↗
PubMed1994

Renin inhibitor: relationship between molecular structure and oral absorption.

Common problems in developing renin inhibitors are low solubility, insufficient oral absorption, and fast hepatic clearance. We focused on the molecular structure of renin inhibitors to overcome these problems. Cyclodextrins (CD) improved the low solubility of renin inhibitors, with beta-CD showing the best ability to dissolve renin inhibitors. The intestinal absorption of renin inhibitors varied with both their solubility and molecular structure. Coadministration of beta-CD improved the intestinal absorption of some renin inhibitors with low solubility as measured by transport into the mesenteric vein in the absorption experiment using the rat intestinal loop. Substitutions at both the N and C terminals was essential for absorption from the small intestine. A naphthyl group at the N-terminal further improved intestinal absorption. A carrier system appeared to be involved in the intestinal absorption of some renin inhibitors. N-methylation at the amide bond of thiazolylalanine suppressed the high hepatic clearance of one of the test compounds 18 which was well absorbed from the small intestine and it improved its oral bioavailability.

Animals↗
PubMed1994

Molecular dissection of influenza virus nucleoprotein: deletion mapping of the RNA binding domain.

Influenza virus nucleoprotein (NP) is associated with the genome RNA, forming ribonucleoprotein cores. To identify the amino acid sequence involved in RNA binding, we performed Northwestern blot analysis with a set of N- and C-terminal deletion mutants of NP produced in Escherichia coli. The RNA binding region has been mapped between amino acid residues 91 and 188, a stretch of residues that contains a sequence that is not only highly conserved among NPs from A-, B-, and C-type influenza viruses but also similar to the RNA binding domain of a plant virus movement protein.

Amino Acid Sequence↗
PubMed1994

Malignant brain stem hyperthermia caused by brain stem hemorrhage.

BACKGROUND: We report two cases of brain stem hemorrhage characterized by severe hyperthermia, rhabdomyolysis, acute renal failure, and a rapidly fatal course. METHODS: A 55-year-old man and a 65-year-old man were admitted with coma-producing brain stem hemorrhage accompanied by hyperthermia. Both underwent ventricular drainage. RESULTS: Within 1 day of onset, both patients developed hyperthermia of over 41 degrees C, increased serum creatine phosphokinase (CPK) level indicating rhabdomyolysis, and acute renal failure. One patient died on the second day and the other on the third day after onset despite supportive treatment. CONCLUSIONS: These cases of brain stem hemorrhage with fulminant hyperthermia should be distinguished from those with simple hyperthermia. They may represent a kind of malignant hyperthermia, in which case dantrolene sodium might be beneficial. Monitoring serum CPK levels would be of help in making the diagnosis early in the course.

Aged↗
PubMed1994

[Efficacy of the "Gen-Probe Mycobacterium Tuberculosis Direct Test (MTD)" for detection of Mycobacterium tuberculosis in clinical specimens--comparison between the MTD and the test by culture on Ogawa's egg medium or in the MB Check System].

Three or more weeks are usually required for detecting Mycobacterium tuberculosis by the known culture methods, and therefore, the development of a rapid bacteriological diagnostic method for M. tuberculosis has been urgently awaited. Recently, Gen-Probe Inc. has developed the "Gen-Probe Mycobacterium Tuberculosis Direct Test (MTD)", which is based on amplification of the ribosomal RNA (rRNA) of M. tuberculosis in clinical specimens and hybridization of the amplified rRNA with a M. tuberculosis-specific DNA probe, as a rapid direct diagnostic method for tuberculosis. We therefore compared the sensitivity and specificity of the MTD in detecting M. tuberculosis with the culture methods on Ogawa's egg medium and in the MB Check System, using 107 clinical specimens as test material. The results obtained are as follows: 1. Of the 61 clinical specimens which were negative when cultured on Ogawa's egg medium, 13 (21.3%) were positive for M. tuberculosis using the MTD, and of the 48 clinical specimens which were negative when cultured in the MB Check System, 8 specimens (16.7%) were positive for M. tuberculosis using the MTD. 2. All of the specimens which yielded growth of M. tuberculosis (identified by the DNA probe) either on Ogawa's egg medium or in the MB Check System, except one, were positive for M. tuberculosis in the MTD. The only one exception was a specimen which was positive for M. tuberculosis in both Ogawa's medium and the MB Check System.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Identifications of atypical mycobacteria by DNA-DNA hybridization and their biotypings with chromogenic substrates].

We developed a new biotyping system for mycobacterial strains. Various chromogenic substrates were incubated with mycobacterial cell suspensions for four hours at 37 degrees C, and strains were typed by their patterns of hydrolysis of these substrates. Commercially available microtiter plate DNA-DNA hybridization system and our biotyping system with chromogenic substrates were applied for the identification of clinically isolated atypical mycobacterial strains, and the results were compared with those obtained by the usual biological methods. Both new methods were proved to be satisfactorily quick and reproducible. The DNA probe method could distinguish M. avium from M. intracellulare and M. nonchromogenicum. Differentiation of these species has been very difficult by other methods. Our new biotyping system also could not differentiate these three species, but could classify some mycobacterial species into several subtypes. The DNA probe method is quick and accurate but expensive. On the contrary, our new biotyping system was found to have the same level of accuracy as the usual methods, but much quicker than the usual methods and less expensive than DNA probe method. We recommend our new biotyping system to the clinical laboratories which hesitate to accept DNA probe method because of its high expenses despite of its high accuracy.

Chromogenic Compounds↗
PubMed1993

Immunoelectron microscopic evidence for the extended conformation of light chains in clathrin trimers.

Clathrin is a major component of the basket-like network of hexagons and pentagons that forms the "coat" on the cytoplasmic face of the plasma membrane and the trans Golgi network during the invagination of coated pits. Soluble clathrin is a three-legged structure (triskelion) comprising three identical heavy chains and three different light chains located toward the center of the triskelion on the proximal segment of the leg. All mammalian light chains contain a central domain of 10 heptad repeats, which is necessary for the interaction with heavy chain. Because the repeats are characteristic of alpha helical coiled coils, we proposed that the central domain had an extended conformation (Kirchhausen, T., Scarmato, P., and Harrison, S. C. et al. (1987) Science 236, 320-324). However, an alternative model has recently been proposed (Nathke, I. S., Heuser, J., Lupas, A., Stock, J., Turck, C. W., and Brodsky, F. M. (1992) Cell 68, 899-910). Here, we use single-molecule electron microscopy of clathrin decorated with monoclonal antibodies directed against different epitopes on light chains to show that the light chain central domain has an extended conformation and reaches along most of the proximal segment of the heavy chain leg.

Amino Acid Sequence↗
PubMed1993

Molecular assembly of influenza virus: association of the NS2 protein with virion matrix.

The NS2 protein, one of the two nonstructural proteins of influenza A virus, was found to exist in virus particles. By immunochemical method, the average number of NS2 in a virus particle was estimated to be 130-200 molecules. After solubilization of viral envelope, NS2 was still associated with ribonucleoprotein cores, but was later dissociated upon removal of the M1 protein. A filter-binding assay in vitro indicated direct protein-protein contact between M1 and NS2. Following chemical cleavage of the M1 protein, NS2 bound only a C-terminal fragment of M1. By immunoprecipitation, NS2-M1 complexes were also detected in virus-infected cell lysates. These observations altogether indicate specific molecular association between M1 and NS2. Biological significance of M1-NS2 interaction is discussed.

Animals↗
PubMed1993

Regulatory effects of matrix protein variations on influenza virus growth.

Influenza virus A/WSN/33 forms large plaques (> 3 mm diameter) on MDCK cells whereas A/Aichi/2/68 forms only small plaques (< 1 mm diameter). Fast growing reassortants (AWM), isolated by mixed infection of MDCK cells with these two virus strains in the presence of anti-WSN antibodies, all carried the M gene from WSN. On MDCK cells, these reassortants produced progeny viruses as rapidly as did WSN, and the virus yield was as high as Aichi. The fast-growing reassortants overcame the growth inhibitory effect of lignins. Pulse-labeling experiments at various times after virus infection showed that the reassortant AWM started to synthesize viral proteins earlier than Aichi. Taken together, we conclude that upon infecting MDCK cells, the reassortant viruses advance rapidly into the growth cycle, thereby leading to an elevated level of progeny viruses in the early period of infection. Possible mechanisms of the M gene involvement in the determination of virus growth rate are discussed, in connection with multiple functions of the M proteins.

Animals↗
PubMed1993

Ambisense coding strategy of the rice stripe virus genome: in vitro translation studies.

Rice stripe virus (RSV), the type species of the tenuivirus group, contains four RNA segments as its genome. Sequence analyses of the three smaller segments indicated that all of them have ambisense coding strategies. To examine the ambisense nature of the genomic RNAs, we synthesized in vitro the RNAs carrying the putative open reading frames (ORFs) by transcribing cDNA clones for RNA segments 2, 3 and 4 in both directions using T7 RNA polymerase and translated each RNA in vitro using two systems: reticulocyte lysates and wheat-germ extracts. We detected the proteins encoded by the ORFs present in the 5'-proximal regions of both viral RNAs (vRNAs) and their complementary RNAs (cRNAs). Translation in vitro of total vRNA generated proteins encoded by the ORFs present in the 5' regions of vRNAs. The overall results are consistent with the prediction that RSV RNAs, at least up to segment 2, are ambisense in their coding strategy.

Capsid↗
PubMed1993

The prognostic significance of exercise-induced silent ST-segment depression in patients after myocardial infarction.

To evaluate the prognostic value of exercise-induced silent ST-segment depression, 157 patients who had suffered myocardial infarction underwent symptom-limited exercise testing and coronary angiography. Patients were divided into 3 groups according to the presence or absence of ischemic ST-segment depression and angina during exercise testing. Group A patients had ST-segment depression without angina. Group B patients had both ST-segment depression and angina. Group C patients had neither ST-segment depression nor angina. All patients were followed without coronary artery bypass graft or percutaneous transluminal coronary angioplasty for an average of 36 months and the frequency of coronary events (cardiac death, recurrent myocardial infarction and unstable angina pectoris) was compared. Group A patients had less severe coronary artery disease, greater coronary reserve during exercise and exercised longer than group B. However, the prognosis of group A was similar to group B, and was worse than group C. Using the Cox proportional hazards model, ischemic ST-segment depression was the most useful index for predicting future coronary events among the baseline values, coronary angiographic and exercise testing variables. However, angina during exercise testing was not an independent predictor. Thus, post-infarction patients showing exercise-induced ST-segment depression should be treated carefully regardless of the presence or absence of angina.

Adult↗
PubMed1993

[Neoadjuvant chemotherapy effective for small cell lung cancer in a nephrectomized patient].

A 67-year-old man, who was nephrectomized due to renal cell cancer 4 years ago, was admitted to examine a mass shadow in the right middle lung field. He was diagnosed as small cell lung cancer with TBLB. Because of impaired renal function, he was treated with CBDCA (300 mg/m2, day 1), THP (30 mg/m2, day 1) and oral etoposide (25 mg/body, for 21 days) without any renal complications. After 3 courses of chemotherapy, the lung CT showed scar lesion despite the disappearance on the chest X-ray, and a right lower lobectomy was performed. Malignant cells remained in the scar lesion, but not in the lymph nodes. These findings suggested the effectiveness of neoadjuvant chemotherapy. This newly-designed chemotherapy procedure is necessary for patients with renal complications.

Aged↗
PubMed1993

[Clinical features of the lung diseases due to Mycobacterium avium and M. intracellulare].

In recent years, it has been made easy to identify Mycobacterium avium and M. intracellulare by DNA-probe test. To evaluate possible clinical differences between the lung diseases due to M. avium and those due to M. intracellulare, we studied a total of 248 cases (136 due to M. avium and 112 due to M. intracellulare). M. avium cases were found more frequently in the eastern part of Japan, whereas M. intracellulare cases were seen more frequently in the western part of Japan. There was no significant difference between M. avium cases and M. intracellulare cases in sex, age, complications, chief complaint, body weight, tuberculin skin test, erythrocyte sedimentation rate, serum protein content, findings of chest X ray. M. avium cases were more frequently detected by health examination. M. avium was more susceptible to cycloserine than M. intracellulare. On the other hand, M. intracellulare was more susceptible to streptomycin and kanamycin. The prognosis of M. intracellulare cases were better than M. avium cases, when compared only the patients who showed positive tuberculin skin test.

Adult↗
PubMed1992

In vitro transcription by RNA polymerase II in extracts of Xenopus oocytes, eggs, and somatic cells.

We describe procedures for preparing extracts of Xenopus oocytes, eggs, and somatic cells that will accurately transcribe class II genes. A variety of viral and Xenopus promoters direct the accurate initiation of transcription by RNA polymerase II in these extracts. Optimal ionic conditions (100-200 mM KCl, 12 mM MgCl2), template concentration (20-40 micrograms/ml), incubation time (30-60 min), and temperature (25 degrees C) for class II gene transcription are described.

Animals↗
PubMed1992

Characterization of RNA polymerase II-dependent transcription in Xenopus extracts.

We examine the RNA polymerase II-dependent transcription directed by several promoters in extracts prepared from distinct developmental stages of Xenopus laevis. RNA polymerase II accurately initiates transcription from the cytomegalovirus, herpes simplex virus thymidine kinase, and Xenopus heat-shock protein (hsp) 70 promoters. The efficiency of transcription of these different promoters is dependent on whether extracts from oocytes, eggs, or somatic cells are used and on the temperature of incubation. In contrast to the viral promoters, the hsp 70 promoter is more active at heat shock temperatures in oocyte and egg extracts (31 degrees-34 degrees C) than at physiological temperatures for Xenopus (20 degrees-25 degrees C). These in vitro transcription extracts should be useful in examining the molecular mechanisms responsible for differential gene expression during Xenopus development.

Animals↗