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Biomedical subjects

S Nagata

Publications and source records attributed to S Nagata.

At least 523 records · Page 29Linked to original sources
PubMed1991

Preferential generation of monoclonal IgG-producing hybridomas by use of vesicular stomatitis virus-mediated cell fusion.

Vesicular stomatitis virus (VSV)-mediated cell fusion was recently proposed as an alternative fusion technique to generate monoclonal antibody (MAb)-producing hybridomas. In order to further examine this technique, we made direct comparative experiments among VSV, Sendai virus (SV) and polyethylene glycol (PEG)-mediated cell fusion in generating MAb-producing hybridomas. The distribution of immunoglobulin (Ig) isotypes secreted by the hybridomas obtained, as well as hybridoma yield and specific hybridoma yield, was compared. The results show that VSV-fusion yielded almost the same number of specific hybridomas as SV- and PEG-fusion in spite of its lower fusion frequency. In addition, VSV-fusion preferentially gave Ig-producing, especially IgG-producing, hybridomas. SV-fusion yielded both hybridomas and specific hybridomas with similar frequency to PEG-fusion, but IgM-producers predominated. These results demonstrate that fusion method has a considerable influence on the isotypes of obtained antibodies, and also suggest an advantage of VSV-fusion for production of IgG monoclonal antibodies.

Animals↗
PubMed1991

The primary structure of skeletal muscle myosin heavy chain: IV. Sequence of the rod, and the complete 1,938-residue sequence of the heavy chain.

In the preceding paper [Maita, T., Miyanishi, T., Matsuzono, K., Tanioka, Y., & Matsuda, G. (1991) J. Biochem. 110, 68-74], we reported the amino-terminal 837-residue sequence of the heavy chain of adult chicken pectoralis muscle myosin. This paper describes the carboxyl terminal 1,097-residue sequence and the linkage of the two sequences. Rod obtained by digesting myosin filaments with alpha-chymotrypsin was redigested with the protease at high KCl concentration, and two fragments, subfragment-2 and light meromyosin, were isolated and sequenced by conventional methods. The linkage of the two fragments was deduced from the sequence of an overlapping peptide obtained by cleaving the rod with cyanogen bromide. The rod contained 1,039 amino acid residues, but lacked the carboxyl-terminal 58 residues of the heavy chain. A carboxyl-terminal 63-residue peptide obtained by cleaving the whole heavy chain with cyanogen bromide was sequenced. Thus, the carboxyl terminal 1,097-residue sequence of the heavy chain was completed. The linkage of subfragment-1 and the rod was deduced from the sequence of an overlapping peptide between the two which was obtained by cleaving heavy meromyosin with cyanogen bromide. Comparing the sequence of the adult myosin thus determined with that of chicken embryonic myosin reported by Molina et al. [Molina, M.I., Kropp, K.E., Gulick, J., & Robbins, J. (1987) J. Biol. Chem. 262, 6478-6488], we found that the sequence homology is 94%.

Amino Acid Sequence↗
PubMed1991

Intracardiac mobile thrombus and D-dimer fragment of fibrin in patients with mitral stenosis.

OBJECTIVE: To investigate the relation between intracardiac thrombus and blood coagulability in patients with mitral stenosis. DESIGN: Prospective study. Cross sectional echocardiography and plasma concentrations of the D-dimer fragment of fibrin were used concurrently to detect intracardiac thrombus in patients with mitral stenosis. SETTING: Department of Medicine, National Cardiovascular Centre, Osaka, Japan. PATIENTS: 63 patients with mitral stenosis. None of them had been receiving any anticoagulants or antiplatelet agents. MAIN OUTCOME MEASURES: Plasma concentrations of D-dimer in patients with a mobile intracardiac thrombus, those in patients with a non-mobile intracardiac thrombus, and those in patients without an intracardiac thrombus. RESULTS: A mobile intracardiac thrombus was found in 10 patients and a non-mobile thrombus in eight. The remaining 45 patients had no intracardiac thrombi. Plasma concentrations of D-dimer in the 10 patients with a mobile thrombus were all greater than 300 ng/ml (mean 983.3, 95% confidence interval 498.9 to 1467.7 ng/ml) and they were significantly higher than those in the patients with a non-mobile thrombus (226.2, 33.6 to 418.8 ng/ml) and the patients without an intracardiac thrombus (147.2, 110.4 to 184 ng/ml). CONCLUSIONS: A high plasma concentration of D-dimer seemed to reflect a hypercoagulable intracardiac state and may be a helpful indicator of the possible presence of mobile intracardiac thrombus in patients with mitral stenosis.

Antifibrinolytic Agents↗
PubMed1991

Hemifacial spasm caused by CP angle AVM associated with ruptured aneurysm in the feeding artery--case report.

A 66-year-old male presented with clinical features of hemifacial spasm. Cerebral angiograms disclosed an arteriovenous malformation (AVM) in the cerebellopontine angle. The hemifacial spasm was caused by a dilated feeding artery of the AVM compressing the facial nerve at the root exit zone. Surgery was not initially performed because of his age and absence of AVM rupture. However, the AVM was associated with a small aneurysm in the feeding artery, which rapidly grew during 20 days after discharge and ruptured causing subarachnoid hemorrhage. The aneurysm was clipped and the feeding artery of the AVM partially obliterated. Careful angiographic examination for associated aneurysms and consequent surgical obliteration to prevent hemorrhage are suggested in cases of AVM.

Aged↗
PubMed1991

Constitutive production of granulocyte colony-stimulating factor by hybrids of a SV40-transformed mouse macrophage and a renal adenocarcinoma cell line.

Mouse macrophage BAM3 cells produced colony-stimulating factors (CSFs) after stimulation with bacterial lipopolysaccharide (LPS). By assaying the CSF using various interleukin 3-dependent cell lines, it was shown that most of the CSFs produced by BAM3 cells were granulocyte CSF (G-CSF). The granulocyte-macrophage CSF (GM-CSF) gene was also expressed in BAM3 cells after stimulation with LPS. When BAM3 cells were fused with the mouse renal adenocarcinoma cell line RAG which does not produce G-CSF, two of four hybrid cell lines constitutively produced large quantities of G-CSF. About 300 bp of the promoter region of mouse G-CSF chromosomal gene was inserted upstream of the Escherichia coli chloramphenicol acetyltransferase gene, and introduced into BAM3, RAG and hybrid cells. The G-CSF promoter was activated by stimulation with LPS, in BAM3 cells, but was inert in RAG cells. On the other hand, there was significant constitutive CAT activity in the hybrid cells.

Adenocarcinoma↗
PubMed1991

Vesicular stomatitis virus-mediated cell fusion subsequent to virus adsorption at different pH values.

Vesicular stomatitis virus (VSV)-mediated cell fusion from without can be induced by transient exposure to low pH, subsequent to adsorption of VSV at neutral pH. To study the mechanism of VSV-induced cell fusion, we examined the effect of pH condition at virus adsorption on acid-inducible VSV-mediated cell fusion. Although the binding of VSV to BHK-21 cells was most efficient under acidic condition (pH 5.7-6.3), extensive cell fusion was not observed under this condition. A temporary exposure to low pH after binding at neutral pH also decreased fusion activity. However, return to neutral pH for 2 min just after the acid binding restored the fusion activity. These results indicate the requirement of neutral pH condition for VSV-mediated cell fusion prior to the acid stimulation which induces conformational change of the virus glycoprotein into a fusogenic form.

Adsorption↗
PubMed1991

[Prognostic significance of radionuclide-assessed right ventricular function in dilated cardiomyopathy].

To assess the prognostic significance of right ventricular function in dilated cardiomyopathy (DCM), we studied consecutive 57 DCM patients. There were 41 men and 16 women, whose mean age was 48 ys. (range 3-68 ys.). The mean LVEF in all patients was 29 +/- 11%, and the mean interval from the onset of symptom of cardiac failure (CHF history) was 4 ys. (range 0-33 ys.). With follow-up of 3.8 ys., five patients had died until the first year, and 14 had died until the third year. By using multivariate regression analysis, there were no prognostic significance in clinical parameters such as age, CHF history, sex, atrial fibrillation, except for NYHA class, and medication at the third year. In survival curves according to Kaplan-Meier method, RVEF and mean PA had predictive value (p less than 0.05), while LVEF did not. The patients with RVEF less than 45% had poor survival rate compared to those with RVEF greater than or equal to 45%. The patients with RVEF less than 45% showed lower LVEF and LVESVI. RVEF may offer prognostic predictive value through the effect of not only mean PA but also left ventricular parameter. In conclusion, radionuclide assessment of right ventricular function should be valuable for the prognostic evaluation of DCM patients.

Adolescent↗
PubMed1991

[Hemodynamic assessment before and after PTMC by using cardiac blood pool scintigraphy].

Rest and exercise cardiac blood pool scintigraphy with 99mTc-RBC were performed in 12 patients with symptomatic mitral stenosis before percutaneous transvenous mitral commissurotomy (PTMC) and at one week, one month after PTMC. Comparison of hemodynamic parameters before and one month after PTMC showed that LVEDV (97.4 +/- 8.9 vs. 111.4 +/- 12.1 ml; p less than 0.01) and diastolic indices (1/3FF: 23.6 +/- 6.5 vs. 30.9 +/- 4.1%; p less than 0.01) both increased, while there was no significant change in LVEF and RVEF. Comparison of symptom-limited bicycle exercise before and one month after PTMC showed that the duration of exercise time (7.6 +/- 1.6 vs. 8.6 +/- 1.4 min; p less than 0.02) and anaerobic threshold (10.6 +/- 3.0 vs. 15.4 +/- 3.2 ml/min/kg; p less than 0.01) increased. In comparison of hemodynamic response before and one month after PTMC, there were significant increases in cardiac output (CO) at the same workload (15 W: 3.9 +/- 0.7 vs. 4.8 +/- 0.8 l/min; p less than 0.05, 30 W: 3.9 +/- 0.7 vs. 5.2 +/- 1.2 l/min; p less than 0.05) despite similar CO at rest (3.5 +/- 0.8 vs. 3.9 +/- 0.7 l/min; NS). We conclude that cardiac blood pool scintigraphy is useful to evaluate improvement of hemodynamic parameters and exercise capacity after PTMC non-invasively.

Adult↗
PubMed1991

[Two pediatric cases of moyamoya disease with progressive involvement from unilateral to bilateral].

Moyamoya disease is defined as having bilateral involvement of the internal carotid arteries. Two pediatric cases of moyamoya disease starting with unilateral involvement of the internal carotid artery are reported. In both cases angiographic findings at onset showed unilateral involvement. Hence, they were filed as a "probable" case according to the diagnostic criteria of the Japanese Cooperative Research Committee. The carotid angiograms on the other side showed totally normal findings. Clinical manifestation, EEG findings, angiographic findings, and PET findings in these cases were the same as those of definitive bilateral moyamoya disease. The only exception was the unilaterality of the findings. One to three years later the occlusive lesions became bilateral, and this met the criteria as a "definite" case. We consider that some of the cases of moyamoya disease actually start with unilateral lesion and develop into bilateral. Angiograms in "probable" cases should be carefully followed up to establish the disease entity of this lesion.

Adolescent↗
PubMed1991

Assessment of myocardial damage in dilated-phase hypertrophic cardiomyopathy by using indium-111-antimyosin Fab myocardial scintigraphy.

For the detection of myocardial cell damage, an 111In-antimyosin Fab study was carried out on seven patients (Group A) in the dilated phase of hypertrophic cardiomyopathy, seven patients (Group B) with dilated cardiomyopathy, and eight control patients (Group C). Imaging was done 48 hr after intravenous injection of 74 MBq of 111In-antimyosin Fab. Myocardial antimyosin uptake was visually graded as 0, +1, +2 or +3. A score of +2 or +3 was considered positive. The heart/lung ratio of antimyosin uptake (antimyosin index) also was determined. Antimyosin uptake was positive in seven (100%), nine (90%) and no (0%) patients in Groups A, B, and C, respectively. The antimyosin index in Groups A and B was 2.46 +/- 0.49 and 2.04 +/- 0.24, respectively, findings were significantly higher than that in Group C (1.51 +/- 0.13) (p less than 0.01). Positive biopsy findings were noted in only two patients in Group A. Thus, antimyosin uptake was increased in dilated phase hypertrophic cardiomyopathy and dilated cardiomyopathy, which suggests ongoing necrotic changes in these patients.

Adult↗
PubMed1990

Vargula hilgendorfii luciferase: a secreted reporter enzyme for monitoring gene expression in mammalian cells.

The small marine ostracod crustacean, Vargula hilgendorfii, produces a bright blue luminous secretion which is ejected into seawater. The luminescence is due to a simple enzyme-catalyzed reaction involving only luciferase, luciferin (substrate), and molecular oxygen. Thus, V. hilgendorfii luciferase (VL) should be useful as a reporter enzyme in studies of gene expression in mammalian cells. Expression plasmids consisting of VL cDNA (vl) linked to the promoters simian virus 40 early region, Rous sarcoma virus long terminal repeat, human elongation factor, or mouse granulocyte colony-stimulating factor were introduced into a series of mammalian cell lines. Following transfection, VL activities in cell extracts and culture media were determined by a rapid light emission assay with V. hilgendorfii luciferin. Parallel experiments were carried out with the chloramphenicol acetyltransferase (CAT)-encoding gene. In all cell lines tested, VL was secreted, allowing the reporter activity to be determined directly from a small aliquot of the culture medium. The results indicate that the secreted VL enzyme is superior to CAT, firefly luciferase, and bacterial luciferase as a convenient and versatile indicator of gene expression in mammalian cells.

Animals↗
PubMed1990

The central inhibitory effect of interleukin-1 on gastric acid secretion.

The effect of interleukin-1 (IL-1) on gastric secretory functions was examined in pylorus-ligated conscious rats. Intracisternal (i.c.) injection of IL-1 beta (1-100 ng) induced dose-related, long-lasting inhibition of gastric acid output, which was due to the reductions of both the amount and the acid concentration of the gastric juice. A much higher dose of IL-1 alpha was required to achieve identical effects on gastric acid secretion when it was given by intravenous routes. The i.c. injection of IL-1 alpha also had an inhibition of gastric secretion. This inhibitory effect of i.c. applied IL-1 beta on gastric acid secretion was completely abolished in indomethacin-pretreated animals but not in reserpine-pretreated ones. These results suggest that IL-1 may have an inhibitory action on the regulation of gastric secretory functions by its central action which is dependent on the eicosanoid metabolism.

Animals↗
PubMed1990

Estrous cycle dependent regulation of peptidylarginine deiminase transcripts in female rat pituitary.

Northern blot hybridization demonstrated 4.5-5.0 kilobase peptidylarginine deiminase mRNA in poly (A)+ RNA-enriched fractions of both male and female pituitaries. Dot blot analysis of total RNA fractions showed more than 50-fold sex difference in the mRNA content. The female pituitary mRNA content showed at least a 50-fold variation during the estrous cycle characterized by elevation at diestrus and proestrus followed by a rapid decline at estrus. The data were discussed in comparison with the sex difference and estrous cycle dependence of the pituitary enzyme content reported previously.

Animals↗
PubMed1990

Purification and characterization of the receptor for murine granulocyte colony-stimulating factor.

A receptor for mouse granulocyte colony-stimulating factor (G-CSF) has been found on the cell surface of mouse myeloid leukemia cell line NFS-60. Chemical cross-linking of the receptor with radioiodinated G-CSF, followed by gel electrophoresis in the presence of sodium dodecyl sulfate, has revealed that the G-CSF receptor in the NFS-60 cells is a single polypeptide of Mr approximately 100,000-130,000. The receptor in the membrane fraction of NFS-60 cells were solubilized in an active form with 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonic acid. The solubilized receptor was purified approximately 100,000-fold to near homogeneity using a G-CSF affinity gel and gel filtration on a Superose 12 column, as measured by the selective precipitation of the 125I-G-CSF-receptor complex by polyethylene glycol. The purified G-CSF receptor has two classes of binding characteristics, one with an equilibrium dissociation constant (Kd) of 120-360 pM which is comparable with the Kd value for the cell-surface receptor, and the other with a higher Kd value of 2.6-4.2 nM. Analyses of the purified receptor by ligand blotting and sucrose density gradient centrifugation indicated that the low-affinity receptor is the monomer of the Mr 100,000-130,000 protein, whereas the high-affinity receptor consists of oligomers of the protein.

Animals↗