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Biomedical subjects

S Maeda

Publications and source records attributed to S Maeda.

At least 487 records · Page 27Linked to original sources
PubMed1994

The p10 gene of natural isolates of Bombyx mori nuclear polyhedrosis virus encodes a truncated protein with an M(r) of 7700.

Sequence analysis of the p10 genes of three Bombyx mori nuclear polyhedrosis virus (BmNPV) isolates collected in Taiwan (Ta) and Japan (T3 and D1) showed that all possessed a deletion of an adenine residue, 210 bp downstream from the first base of the initiation codon when compared to the p10 gene of Autographa californica (multinucleocapsid) NPV (AcMNPV). This deletion caused a downstream termination codon to come inframe with the coding sequence of p10, so that the p10 gene of BmNPV encoded a protein of 70 amino acid residues with an M(r) of 7700. This is considerably shorter than the 10,000 M(r) protein encoded by the closely related AcMNPV.

Amino Acid Sequence↗
PubMed1994

Long-Evans A and C rat strains susceptible to clastogenic effects of chemicals in the bone marrow cells.

The clastogenic responses to direct- and indirect-acting carcinogens in bone marrow cells of LEA, LEC, Wistar and SD rats were compared. The frequency of chromosome aberrations (CA) induced by n-butyl-N-nitrosourea or methylmethanesulfonate (MMS), which does not need metabolic activation, was significantly higher in both LEA and LEC rats than in Wistar or SD rats. When bone marrow cells of each rat strain were exposed to MMS in vitro, they also showed the same tendency in CA frequency. Therefore, the high sensitivity of both LEA and LEC rats to the clastogenic effects of direct-acting carcinogens seems to result from the sensitivity of the bone marrow cells themselves. On the other hand, the CA frequency induced by 7,12-dimethylbenz[a]anthracene (DMBA) or aflatoxin B1 (AFB1), which requires metabolic activation, was lower in LEC rats than in the other 3 strains. The CA frequency induced by DMBA or AFB1 in LEC rats fed Cu-free diet since birth (Cu-free LEC rats) was higher than that in LEC rats given normal diet and lower than that in LEA rats, although the difference was statistically significant only between Cu-free LEC rats and LEC rats treated with DMBA. The copper concentrations in the livers of LEA, Cu-free LEC and LEC male rats aged 4 weeks were 5.0 +/- 0.4, 33 +/- 7.7 and 106 +/- 3.4 micrograms/g wet weight, respectively. These results suggest that the lower sensitivity of LEC rats to the clastogenic effects of indirect-acting carcinogens may be due to the effect of the large amount of copper accumulated in LEC rat liver.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

A cysteine protease encoded by the baculovirus Bombyx mori nuclear polyhedrosis virus.

Sequence analysis of the BamHI F fragment of the genome of Bombyx mori nuclear polyhedrosis virus (BmNPV) revealed an open reading frame whose deduced amino acid sequence had homology to those of cysteine proteases of the papain superfamily. The putative cysteine protease sequence (BmNPV-CP) was 323 amino acids long and showed 35% identity to a cysteine proteinase precursor from Trypanosoma brucei. Of 36 residues conserved among cathepsins B, H, L, and S and papain, 31 were identical in BmNPV-CP. In order to determine the activity and function of the putative cysteine protease, a BmNPV mutant (BmCysPD) was constructed by homologous recombination of the protease gene with a beta-galactosidase gene cassette. BmCysPD-infected BmN cell extracts were significantly reduced in acid protease activity compared with wild-type virus-infected cell extracts. The cysteine protease inhibitor E-64 [trans-epoxysuccinylleucylamido-(4-guanidino)butane] inhibited wild-type virus-expressed protease activity. Deletion of the cysteine protease gene had no significant effect on viral growth or polyhedron production in BmN cells, indicating that the cysteine protease was not essential for viral replication in vitro. However, B. mori larvae infected with BmCysPD showed symptoms different from those of wild-type BmNPV-infected larvae, e.g., less degradation of the body, including fat body cells, white body surface color due presumably to undegraded epidermal cells, and an increase in the number of polyhedra released into the hemolymph. This is the first report of (i) a virus-encoded protease with activity on general substrates and (ii) evidence that a virus-encoded protease may play a role in degradation of infected larvae to facilitate horizontal transmission of the virus.

Amino Acid Sequence↗
PubMed1994

Comparative clinicopathological and immunohistochemical study of ras and p53 in flat and polypoid type colorectal tumours.

Mutations in oncogenes and tumour suppressor genes may have an important oncogenic role. Although flat type tumours have been frequently detected in recent years, ras and p53 expressions have not been studied in these tumours. Using a monoclonal and polyclonal antibody to the ras p21 and p53 product, paraffin wax embedded sections of 98 colorectal tumours (43 cases of the flat type colorectal tumour and 55 cases of polypoid type tumour) were stained using the immunoperoxidase technique. Staining was evaluated by light microscopic examination. Positive staining rate of ras p21 for the flat type was 0%; for the polypoid type, it was 60% in cancer with submucosal invasion, 82% in adenoma with high grade dysplasia, and 0% in adenoma with low grade dysplasia. The positive staining rate of p53 for the flat type was 50% in submucosal cancer, 9% in adenoma with high grade dysplasia, and 0% in adenoma with low grade dysplasia. For the polypoid type, it was 40% in submucosal cancer, 12% in adenoma with high grade dysplasia, and 0% in adenoma with low grade dysplasia. The intermediate staining rate of p53 in the polypoid type was 20% in submucosal cancer and 41% in adenoma with high grade dysplasia. It was seen that p53 was commonly expressed in both flat and polypoid lesions, p21 was not expressed in flat lesions, whereas it was commonly expressed in polypoid neoplasms. In the flat type cancer, a genetic change different from that of the polypoid type cancer is suggested.

Adenoma↗
PubMed1994

Alteration of plasma endothelin-1 by exercise at intensities lower and higher than ventilatory threshold.

The purpose of this study was to investigate whether the release of endothelin-1 (ET-1), a potent vasoconstrictor peptide produced by vascular endothelial cells, is induced by exercise. Venous plasma concentrations of ET-1 were measured by sandwich-enzyme immunoassay before and after endurance exercise with a cycle ergometer at different intensities. Male intercollegiate athletes participated in the study and performed cycle ergometer exercise of 30 min duration at intensities of 90 or 130% of their individual ventilatory threshold (VT). The plasma concentration of ET-1 was slightly but significantly increased after exercise at 90% and markedly increased after exercise at 130% of individual VT. The increase in ET-1 was greatest 30 min after exercise at both intensities. It was first demonstrated that the plasma concentration of ET-1 was significantly increased after exercise: the greater the intensity, the greater the extent of the increase in plasma ET-1 concentration. However, the precise physiological roles of ET-1 during exercise remain to be elucidated.

Adolescent↗
PubMed1994

Theophylline attenuates circulating vitamin B6 levels in children with asthma.

This study was undertaken to investigate the effect of theophylline on circulating vitamin B6 levels in children with asthma. Twenty-six asthmatic children, including 20 patients who were treated with slow-release theophylline and 6 patients not receiving any type of theophylline preparation, were enrolled in this study. Steady state serum theophylline and vitamin B6 [pyridoxal 5'-phosphate (PLP) and pyridoxal (PL)] levels were evaluated in these patients. A depression of serum PLP levels existed in asthmatic children treated with theophylline compared to those not receiving theophylline (5.3 +/- 0.5 vs. 9.0 +/- 1.4 ng/ml, mean +/- SEM; p < 0.05). A significant negative correlation between the serum levels of PLP and theophylline was demonstrated in the subjects of this study (rs = -0.609, p < 0.001). Oral administration of 200 mg of theophylline (TheoDur) to 5 children with asthma significantly depressed serum PLP levels 4 h after the drug intake (p < 0.05), whereas theophylline did not affect serum PL levels. From these results, we conclude that theophylline induces a depression of circulating PLP levels in asthmatic children.

Adolescent↗
PubMed1994

A case of lipoprotein glomerulopathy successfully treated with probucol.

A 54-year-old woman presented proteinuria and severe hyperlipoproteinemia, She had type III hyperlipoproteinemia with the phenotype E2/2. Renal biopsy specimen revealed lipoprotein thrombi within the glomerular capillary lumina without tubulointerstitial lesion and deposition of IgA in the mesangium and peripheral capillary loops, indicating lipoprotein glomerulopathy with IgA nephropathy. Treatment with probucol resulted in the improvement of both hyperlipoproteinemia and proteinuria with the disappearance of the lipoprotein thrombi in the glomerular capillary without any change in the mesangial IgA deposition. The data suggest that probucol may be effective against the early stage of lipoprotein glomerulopathy with less lipoprotein thrombi and without tubulointerstitial damage.

Female↗
PubMed1994

From EMG to formant patterns of vowels: the implication of vowel spaces.

With a few exceptions, EMG data are interpreted with reference to the intended output, such as the phonetic description of utterances spoken by speakers. For a more rigorous interpretation, the data should also be analysed in terms of the displacement of the articulators and the acoustic patterns. In this paper, we describe our attempts to calculate the formant patterns from EMG activity patterns via an articulatory model. The value of the model parameters, such as the tongue body position or tongue body shape, is derived from the EMG activities of the specific pairs of antagonistic tongue muscles. The model-calculated F1-F2 patterns for 11 American English vowels correspond rather well with those measured from the acoustic signals. What strikes us is the simplicity of the mappings from the muscle activities to vocal-tract configurations and to the formant patterns. We speculate that the brain optimally exploits the morphology of the vocal tract and the kinematic functions of the tongue muscles so that the mappings from the muscle activities (production) to the acoustic patterns (perception) are simple and robust.

Electromyography↗
PubMed1994

Studies on the preparation of bioactive lignans of oxidative coupling reaction. I. Preparation and lipid peroxidation inhibitory effect of benzofuran lignans related to schizotenuins.

The parent benzofuran lignan 4 of schizotenuins 1-3 and related compounds were efficiently prepared by a judicious use of the oxidative coupling reaction, and were tested for their inhibitory effects on lipid peroxidation in rat brain homogenate and rat liver microsomes. Among twelve compounds tested in rat brain homogenate, compounds 13, 14 and 16 showed prominent inhibitory activity. Compounds 13 and 16 were then tested in rat liver microsomes, and their activity was found to be more potent than schizotenuin A (1) and much more potent than that of (+/-)-alpha-tocopherol.

Animals↗
PubMed1994

Studies on the preparation of bioactive lignans by oxidative coupling reaction. II. Oxidative coupling reaction of methyl(E)-3-(4,5-dihydroxy-2-methoxyphenyl)propenoate and lipid peroxidation inhibitory effects of the produced lignans.

The oxidative coupling reaction of methyl (E)-3-4(4,5-dihydroxy-2-methoxyphenyl)propenoate (10), obtainable from esculetin, has been studied using silver oxide and potassium hexacyanoferrate(III). The products were separated, after acetylation, by silica gel column chromatography. 1-Aryl-1,2-dihydronaphthalene derivative 12 was obtained as a major product, accompanied by the benzo[kl]xanthene derivative 13. In the oxidation with silver oxide, a benzodioxane compound 14a was produced additionally in a minor amount. Thus, the course of the reaction differed notably from those of ferulic or caffeic acid derivatives. The compounds 11, 12, 13 and 14a were tested for their inhibitory effects on lipid peroxidation in rat brain homogenate and rat liver microsomes. They showed activities more effective than that of idebenone in rat brain homogenate, and were found to be more potent than benzofuran lignans 4 and 5, and much more potent than (+/-)-alpha-tocopherol in rat liver microsomes.

Animals↗
PubMed1994

Studies on the preparation of bioactive lignans by oxidative coupling reaction. III. Synthesis of polyphenolic benzofuran and coumestan derivatives by oxidative coupling reaction of methyl (E)-3-(4-hydroxy-2-methoxyphenyl)propenoate and their inhibitory effect on lipid peroxidation.

Three dihydrobenzofuran derivatives 11, 19, 22, a Pummerer's ketone 20 and a dimeric phenylpropanoid 24 were synthesized by oxidative coupling reaction of methyl (E)-3-(4-hydroxy-2-methoxyphenyl)propenoate 10, which was prepared from umbelliferone. The major product 11 was converted into its acetate 21 and schizotenuin D analogs 27, 28, 29. A new coumestan derivative 13 was synthesized from 29. Ten synthetic compounds thus obtained were tested for inhibitory effects on lipid peroxidation in rat brain homogenate.

Animals↗
PubMed1994

Analysis for the stage specific antigen of the primordial germ cells in the chick embryo.

A monoclonal antibody 2C9 (IgM chi-light chain) was established by fusing the myeloma cells (X63-Ag8-653) with the spleen cells immunized with sexually indifferent gonads from 6-day chick embryos. The 1- to 17-day chick embryos were examined by immunohistochemistry (ABC technique). As a result, the 2C9 antigen first appeared in the cytoplasm of some primordial germ cells (PGCs) of the germinal crescent at 1 day of incubation. The reactivity was also detected in the hypoblastic cells. This antigen may be produced at this stage. After the migrating stage, 2C9-reactive PGCs were increased in number. From this stage to the sexually differentiating stage (7 days of incubation), the 2C9 antibody was reactive all over the cytoplasm of PGCs in both sexes. In the female gonads, the reactivity disappeared at 8 days of incubation, but not in the male. The reactivity of male PGCs was gradually decreased and disappeared until 14 days of incubation. Since the stages of disappearance of this antigen in both sexes seem to depend on the differentiation of the oogonia and spermatogonia, this antigen may disappear in accordance with germ cell differentiation. Cross-reactions were observed in hepatocytes, gastrointestinal endoderm and some mesonephric tubules. By SDS-PAGE and immunoblotting methods, all the extracts from these tissues revealed two bands; 109 kilodalton (kDa) and 64 kDa, suggesting that the 2C9 antibody detects the same molecule in each kind of cells. The 2C9 antibody may be a useful cell-marker and/or probe for analysis of the germ cell differentiation in chick PGCs.

Animals↗
PubMed1994

Effect of theophylline on serum uric acid levels in children with asthma.

This study was undertaken to investigate the effect of theophylline on serum uric acid levels in children with asthma. Twenty-seven asthmatic children, including 21 patients who were treated with slow-release theophylline and 6 patients not receiving any type of theophylline preparation, were enrolled in this study. Serum uric acid levels were increased in the asthmatic children treated with theophylline compared to those not receiving this agent (6.28 +/- 0.29 mg/dl, mean +/- SEM, vs. 4.82 +/- 0.52 mg/dl, p < 0.05). A significant positive correlation between the serum levels of uric acid and theophylline was demonstrated in the patients of this study (rs = 0.596, p < 0.01). All the patients in whom theophylline administration was stopped showed significant decreases in serum uric acid levels (p < 0.05). From these results, we conclude that theophylline increases serum uric acid levels in children with asthma, just as it does in adult asthmatics.

Adolescent↗
PubMed1994

[Anaphylactic reaction to aprotinin following topical use of biological tissue sealant].

Biological tissue sealant is used for facilitation of intra-operative hemostasis. It is composed of cryoprecipitated fibrinogen, bovine-thrombin and bovine-aprotinin. In this report, we describe a 38-yr-old woman in whom severe anaphylactic shock occurred immediately after the topical use of biological tissue sealant on the completion of modified radical mastectomy. The patient's past history and pre-operative laboratory values were unremarkable except for mild nasal allergy. Postoperative prick tests for bovine-serum, bovine-thrombin and bovine-aprotinin were positive. Total IgE level was normal. By the radioallergosolbent tests (RAST), specific IgE antibodies for aprotinin were elevated to the class 2 level. Drug induced lymphocyte stimulation tests (DLST) were negative. These indicated that the case was an aprotinin-induced anaphylaxis during general anaesthesia. The level of CH50, C4, C1q and C5 decreased in the serum sample immediately after the shock, but C3 was unchanged. It was considered to be a direct degradation of the complement by the proteolytic enzymes. Biological tissue sealant should be used cautiously bearing in mind the possibility of anaphylactic complication.

Adult↗
PubMed1994

Cell-colony hybridization on a nitrocellulose filter to identify clones expressing a transfected gene.

Cells that are transfected with a growth-inhibitory gene can be isolated by using a dominant selective marker. Such isolated clones, however, do not always express the transfected gene. Therefore, clones in which a transfected gene is integrated and expressed should be selected further. We have developed a simple method of identifying such expression-positive clones. We modified the filter hybridization process so that cultured cells are directly transferred to a nitrocellulose filter, immobilized, and hybridized with radiolabeled DNA probes. This method is sensitive enough to detect the presence or the expression of a single-copy gene, and ideal for identifying clones that stably express a transfected gene.

Cells, Cultured↗
PubMed1994

Temporary threshold shifts in fingertip vibratory sensation from hand-transmitted vibration and repetitive shock.

Temporary threshold shifts (TSSs) in vibrotactile perception produced by continuous vibration and repetitive shocks having one complete cycle of a 100 Hz sine wave and exponential decays. The repetition rate of the cycles was 5, 25, 50, or 100/s, while the root-mean-square (r.m.s.) acceleration measured over exposure of five minutes was held constant (weighted according to British Standard (BS) 6842 and International Standard (ISO) 5349). When exposed to five shocks per second at each of the three frequency-weighted acceleration magnitudes, the subjects developed a small TTS. Exposure to 100 shocks per second (continuous vibration) at each of the three frequency-weighted acceleration magnitudes caused a large TTS, although the total frequency-weighted energy was the same as when exposed to five shocks per second. The results suggest that the equal energy hypothesis underlying BS 6842 and ISO 5349 is inappropriate for the prediction of the TTS produced by repetitive shocks.

Adult↗