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Biomedical subjects

S Takeda

Publications and source records attributed to S Takeda.

At least 613 records · Page 34Linked to original sources
PubMed1990

Structural studies of the contractile tail sheath protein of bacteriophage T4. 2. Structural analyses of the tail sheath protein, Gp18, by limited proteolysis, immunoblotting, and immunoelectron microscopy.

The molecular structure of the T4 phage tail sheath protein, gp18, was studied by limited proteolysis, immunoblotting, and immunoelectron microscopy. Gp18 is extremely resistant to proteolysis in the assembled form of either extended or contracted sheaths, but it is readily cleaved by proteases in the monomeric form, giving rise to stable protease-resistant fragments. Limited proteolysis with trypsin gave rise to a trypsin-resistant fragment, Ala82-Lys316, with a molecular weight of 27K. Chymotrypsin- and thermolysin-resistant fragments were also mapped close to the trypsin-resistant region. The time course of trypsin digestion of the monomeric gp18 as monitored by SDS-polyacrylamide gel electrophoresis and immunoblotting of the gel revealed that the polypeptide chain consisting of 658 amino acid residues is sequentially cleaved at several positions from the C terminus. The N-terminal portion, Thr1-Arg81, was then removed to form the trypsin-resistant fragment. Immunoelectron microscopy revealed that the polyclonal antibodies against the trypsin-resistant fragment bound to the tail sheath. This supported the idea that at least part of the protease-resistant region of gp18 constitutes the protruding part of the sheath protein as previously revealed with three-dimensional image reconstruction from electron micrographs by Amos and Klug [Amos, L. A., & Klug, A. (1975) J. Mol. Biol. 99, 51-73].

Amino Acid Sequence↗
PubMed1990

[Intraoral ultrasound of the tongue tumor].

Transcutaneous ultrasonography scanned through the submandibular triangle has been effectively utilized for the evaluation of tongue tumors. However, because of lacking an appropriate sonic window, tumors located in the anterior portion of the tongue can not be demonstrated on the transcutaneous ultrasonogram. Intraoral ultrasonography using an echoendoscopy was effective for evaluating neoplasms of the tongue, and could clearly demonstrate tongue tumors, which failed to be shown on the transcutaneous ultrasonograms. In addition, intraoral ultrasonograms could provide more accurate anatomical informations concerning the tumor extent than the transcutaneous ultrasonograms.

Endoscopy↗
PubMed1990

Primary structure of a precursor for the delta-subunit of sweet potato mitochondrial F1-ATPase deduced from full length cDNA.

A cDNA library constructed from poly(A)-rich RNA of the sweet potato tuberous root using a newly developed plasmid vector carrying tac-SP6 promoters was used to identify full length cDNAs for the nuclear-encoded delta-subunit of mitochondrial F1-ATPase by oligonucleotide-hybridization selection. Selected clones contained cDNA insert which carry the entire coding capacity for the pre-delta-subunit, since the RNA transcribed in vitro from SP6 promoter on the vector directed the synthesis of pre-delta-subunit polypeptide in a wheat germ in vitro translation assay. The nucleotide sequence of one of these cDNAs indicates that it can code for the pre-delta-subunit of 244 amino acids of which 199 amino acids encode the mature subunit. The amino acid sequence of the mature delta-subunit shows similarities of about 18-25% amino acid positional identity with the delta-subunits of bacterial F1-ATPases, about 26% with the delta-subunit of chloroplast CF1-ATPase, and about 32-37% with oligomycin sensitivity conferring proteins of animal and fungal mitochondria. The N-terminal presequence of the precursor composed of maximum of 45 amino acids does not show any obvious sequence homology with either the transit peptide of the nuclear-encoded pre-delta-subunit of chloroplast CF1 or the presequence of the nuclear-encoded pre-oligomycin sensitivity conferring proteins. At least two types of the delta-subunit cDNAs with very similar structures were identified from the library, and the presence of multiple copies of the delta-subunit gene in the hexaploid genome of the sweet potato is also suggested by genomic Southern blot hybridization.

Amino Acid Sequence↗
PubMed1990

Increased fibrin/fibrinogen degradation products without increase of plasmin-alpha 2-plasmin inhibitor complex after hepatectomy for hepatocellular carcinoma.

To clarify the meaning of increased serum fibrin/fibrinogen degradation products (FDP) in the postoperative period of hepatectomy, blood coagulation and fibrinolysis were studied using recently devised laboratory assays of a group of 30 patients with hepatocellular carcinoma. Twenty of these cases were associated with liver cirrhosis. As a control group, 15 patients with colorectal carcinoma without liver diseases were also selected. In the early postoperative period following hepatectomy, a hypercoagulable state designated as intravascular thrombin generation was confirmed from the finding of increased plasma levels of fibrinopeptide A (FPA). Fibrinopeptide B beta 15-42 (B beta 15-42) in the plasma also increased immediately after the peak of FPA, followed by a gradual decline in B beta 15-42 levels. On the other hand, FDP in the serum increased significantly rather late in the postoperative period following hepatectomy without increased levels of plasmin-alpha 2-plasmin inhibitor complex. However, postoperative increase of fibrin/fibrinogen degradation products-D (FDP-D) was modest and not different from the colectomy group. Therefore, the relevance of intravascular coagulation in the hepatectomy for the patients with liver cirrhosis seems not to be significant, and then such an increase of FDP in the serum seems to be related to other mechanisms.

Adult↗
PubMed1990

Lewy bodies in the lower sacral parasympathetic neurons of a patient with Parkinson's disease.

Lewy bodies were observed incidentally in the neurons of the dorsal group of nucleus intermediolateralis of the 3rd sacral segment of the spinal cord in a 74-year-old male with Parkinson's disease. The findings indicate the degeneration of the preganglionic parasympathetic neurons innervating the internal anal sphincter. The correlation between the findings and the mechanism of constipation in this disease are discussed.

Aged↗
PubMed1990

Involvement of extraocular muscle in mitochondrial encephalomyopathy.

We carried out a histological examination of the extraocular muscles (EOMs) in a case of myoclonus epilepsy associated with ragged-red fibers (MERRF) and two cases of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS), which did not manifest external ophthalmoplegia clinically. By light microscopy, many granular and vesicular fibers were seen associated with endomysial fibrosis. Electron microscopy revealed that the fibers showed prominent accumulation of abnormal mitochondria, extensive loss of myofibrils, proliferation of free sarcoplasmic reticulum and an increased amount of lipid vacuoles. These changes were more pronounced in MELAS than in MERRF. Hirano bodies were often seen in the subsarcolemmal area of muscle fibers and also in the intramuscular myelinated nerve fibers and axon terminals. These findings suggest the presence of mitochondrial myopathy of the EOMs in cases of MELAS and MERRF.

Actin Cytoskeleton↗
PubMed1990

TAT-59, a new triphenylethylene derivative with antitumor activity against hormone-dependent tumors.

The antiestrogenic action of TAT-59 [(E)-4-[1-[4-[2-(dimethylamino)ethoxy]-phenyl]-2-(4-isopropyl) phenyl-1-butenyl]phenyl monophosphate] was characterized and compared with that of Tamoxifen (TAM). Its active metabolite, 4-OH-TAT-59, had a high binding affinity to estrogen receptor (ER), present in the cytosol of the uterus of immature rat, similar to estradiol. TAT-59 and 4-OH-TAT-59 inhibited in vitro estrogen-stimulated proliferation of MCF-7 cells at a lower concentration than TAM. In the absence of estradiol, TAT-59 and 4-OH-TAT-59 were effective at a lower concentration than that of 4-OH-Tamoxifen (4-OH-TAM), the active metabolite of TAM. In uterine growth inhibition, the effective dose of TAT-59 was about 3-6-fold lower than that of TAM, in various administration schedules. The minimum effective dose of TAT-59 against in vivo MCF-7 cells was about 3-fold lower than that of TAM. In DMBA-induced rat mammary tumors, TAT-59 inhibited the growth of existing tumors at about a 10-fold lower dose than TAM. Especially in the tumors with low ER levels (10-20 fmol/mg protein), TAT-59 showed a significantly stronger inhibitory effect than TAM. These experiments showed that TAT-59 was more effective in lower doses than TAM, even against the tumors with low ER content.

Animals↗
PubMed1990

Expression of goat alpha-lactalbumin in Escherichia coli and its refolding to biologically active protein.

A cDNA encoding the mature region of goat alpha-lactalbumin and the 3'-non-coding region was fused to cDNA of the N-terminal half of porcine adenylate kinase which had been placed under the control of the tac promoter in an expression vector in Escherichia coli. In addition, a methionine codon was inserted between the two cDNAs. When the plasmid carried the full-length 3'-non-coding region, little accumulation of the fused protein was observed. However, the deletion of two-thirds of the 3'-non-coding region produced significant expression of the fused protein in E. coli strain JM105. Since goat alpha-lactalbumin contains no methionine residue, the mature goat alpha-lactalbumin was isolated by CNBr digestion of the fused insoluble protein and refolded using thioredoxin. The homogeneous and biologically active goat alpha-lactalbumin was purified by Ca2+ ion-dependent hydrophobic chromatography.

Animals↗
PubMed1990

Menogaril, an anthracycline compound with a novel mechanism of action: cellular pharmacology.

Menogaril, an anthracycline compound possessing a significant antitumor activity after both po and iv administration, has been introduced into clinical trials. However, its mechanism of action has not been clarified yet. This study revealed that its cytotoxicity correlated very well with the inhibition of macromolecular synthesis, indicating the involvement of interaction with DNA. The spectrophotometric study showed a weaker binding of this compound to calf thymus DNA when compared to that of doxorubicin (adriamycin). Despite the lower binding affinity of menogaril to DNA, pronounced DNA cleavage was observed in an intact cell system, indicating that the character of the interaction with DNA is different from intercalation. In contrast to doxorubicin, menogaril is extensively localized in the cytoplasm. The cytoplasmic localization prompted us to study its effect on cytoskeleton proteins. It was found that menogaril inhibited the initial polymerization rate of tubulin, indicating a possible contribution of this process to the overall cytotoxicity of menogaril.

Animals↗
PubMed1990

Ultrasonographic monitoring of the placenta in patients with bleeding during the first and second trimesters.

Thirteen patients with vaginal bleeding in the first and second trimester, in 730 pregnancies confirmed with live fetuses, were diagnosed as having subchorionic hematoma at the perivillous or periplacental region by a real-time B-mode scan device. In 9 of the 13 patients, the hematoma disappeared within 1 to 3 months after detection, while in 2 patients it increased in size. Seven of the 13 pregnancies progressed to full term (53.8%), 3 ended in premature deliveries (23.1%) and 3 in spontaneous abortions (23.1%). In 5 of the 13 patients, PROM occurred. Pathological examinations revealed 5 circumvallate (38.5%) and 2 circummarginate (15.4%) placentas. Since our clinical observation indicates that subchorionic hematoma and marginal separation of the placenta may be important causes of bleeding during pregnancy, monitoring of the placenta and fetus by ultrasound was used to obtain precise information in order to manage patients with bleeding. It might be speculated that extrachorial placenta results from subchorionic hematoma or its absorption.

Adult↗
PubMed1990

[Effects of Shosaiko-to-go-keishikashakuyaku-to (TJ-960) on the valproic acid induced anomalies of rat fetuses].

Shosaiko-to-go-keishikashakuyaku-to (TJ-960) is an extract of nine herbal drugs (Paeoniae radix, Cinna momi cortex, Bupleuri radix, Zingiberis rhizoma, Glycyrrhizae radix, Ginseng radix, Scutellariae radix, Pinelliae tuber and Zizyphi fructus) that has a potent anticonvulsant action. The rat fetuses treated orally with TJ-960 during the organogenesis period (days 7-17 of gestation) revealed no anomalies (up to 3000 mg/kg/day). When TJ-960 was co-administered with sodium valproate (VPA, 400 mg/kg) during the organogenesis period, embryonic resorption, fetal body weight, ossification and skeletal variation or anomalies induced by VPA were markedly reduced. The maternal plasma and embryonic concentration of VPA with TJ-960, however, were not significantly different from VPA alone. These results suggest that TJ-960 has protective effects against the teratogenicity of VPA.

Abnormalities, Drug-Induced↗
PubMed1990

Effect of gomisin A (TJN-101) on the arachidonic acid cascade in macrophages.

It has been reported that leukotrienes (LTs) may play a role in inflammatory liver diseases, and several inhibitors of LTs show an inhibitory effect on experimental liver injuries. In this study, the effect of Gomisin A (TJN-101), which is a lignan component of schisandra fruits, on the arachidonic acid cascade in macrophages was examined to explain the mechanisms of the inhibitory effect of TJN-101 on liver injuries. The production of leukotriene B4 was suppressed by treatment with TJN-101, while the activity of 5-lipoxygenase was not affected. The release of arachidonic acid from macrophages stimulated with fMet-Leu-Phe or the Ca++ ionophore A23187 was suppressed by treatment with TJN-101. The activity of phospholipase A2 was not affected by treatment with TJN-101. These results suggested that TJN-101 produces an inhibitory effect on the biosynthesis of LTs by preventing the release of arachidonic acid, and it was thought that the preventive effect on the arachidonic acid cascade may be partially associated with the inhibitory effect of TJN-101 on liver injuries.

Animals↗
PubMed1990

[An epidemiological study of lung cancer among workers exposed to bis(chloromethyl)ether].

An epidemiological study of lung cancer was carried out in two dyestuff factories (Factory K and U), where bis (chloromethyl) ether, BCME, was manufactured and used in the initial process of dyestuff production in Wakayama Prefecture, Japan. BCME was used from 1955 to 1970 in Factory K, and from 1960 to 1968 in Factory U. Subjects were 35 men who had been exposed to BCME in each factory. In this study 13 lung cancer cases were found (including 5 cases reported by Sakabe (Ind Health 1973]. The main results obtained were as follows: 1) The exposure period of 13 lung cancer cases to BCME was 86.9 +/- 34.9 months (mean +/- SD) and the latent period was 13.5 +/- 6.6 yr. The age at death was 46.1 +/- 9.5 yr and 7 cases died between the age of 40 and 49. 2) The initial symptoms of lung cancer due to BCME were not different from those of non-occupational lung cancer. The identified histological types of eight cancer cases were small cell carcinoma in 5 cases, adenocarcinoma in 3 cases and large cell carcinoma in the remaining case. 3) Standardized mortality ratio (SMR) was 23.5 at Factory K and 17.9 at Factory U. An excess death due to lung cancer among workers exposed to BCME was observed. 4) The shortest exposure period of the 13 lung cancer cases was only 23 months and therefore workers who had been exposed to BCME for under 3 yr must be examined for lung cancer periodically.

Adenocarcinoma↗
PubMed1990

[Hemodynamic features of hypotension induced by nicardipine in dogs].

Hemodynamic features of hypotension induced by nicardipine were studied in 18 mongrel dogs under 0.87% halothane in oxygen (1MAC). They were randomly allocated to one of two groups. Group C received no vasodilator therapy and served as control and group N received infusion of nicardipine. Mean arterial pressure decreased and was maintained at 60 mmHg for 60 minutes in group N. No change was noted in hemodynamic variables measured in group C throughout the experiment. During and after induced hypotension in group N, cardiac index (CI), stroke volume index (SVI), central venous pressure (CVP), and right ventricular stroke work index (RVSWI) increased significantly compared with the control values. On the other hand, systemic vascular resistance (SVR) was significantly reduced, reaching 25% of the control value at the end of hypotension period. Heart rate showed a progressive increase but not significantly. Left ventricular maximum dp/dt showed a moderate increase during hypotension, but then decreased gradually to the control value after induced hypotension. Left ventricular stroke work index (LVSWI) and pulmonary vascular resistant (PVR) were unchanged from the control value during and after induced hypotension. The data indicate that nicardipine is a potent systemic vasodilator with hyperdynamic hemodynamic effects in addition to significant increase in right ventricular function.

Animals↗
PubMed1990

[Relationship between antitumor activity and the inhibition of thymidylate synthase after oral administration of UFT in nude mice bearing human tumor].

We studied the relationship between antitumor efficacy of UFT, which is a most widely used drug among fluorinated pyrimidines recently, and its effect on the content and the inhibition rate of thymidylate synthase (TS) in 15 human tumor xenografts derived from stomach, colon, breast and pancreatic cancer patients. There was a linear relationship between the content of TS and tumor mass doubling time (MDT). It may be shown that TS content reflects the growth rate of tumor cells. It should be stressed that tumor growth inhibition rate (TGIR), induced by UFT, correlated well with the inhibition of TS (TSI), particularly in the stomach and breast cancer. These results demonstrate that the measurement of inhibition rate of TS is important for the prediction and evaluation of clinical efficacy of UFT.

Administration, Oral↗
PubMed1990

[Analysis of the mechanism of increased antitumor activity of UFT after combined treatment with CDDP].

Previously we have reported the efficacy of the combination therapy of UFT with CDDP against several human cancer xenografts implanted in nude mice. Among all cell lines tested, KM20C (Human colon adenocarcinoma) has shown the most pronounced synergistic antitumor effect after administration of CDDP prior to UFT. The effect of CDDP administered after UFT and that of either drug alone were weaker. To clarify the mechanism of this synergistic effect, the change of the poolsize of reduced folate in KM20C, induced by CDDP treatment, was measured. The pretreatment with CDDP increased the poolsize of CH2-H4 folate and H4 folate and increased the binding of FdUMP to the dTMP synthase of an intact cells. Based on the above data, it was concluded that the enhancement of cell sensitivity to UFT was caused by the CDDP-induced increase of the reduced folate pool, in consequence leading a better binding of FdUMP generated from UFT to dTMP synthase, a target enzyme for the antitumor activity of fluorinated pyrimidines.

Adenocarcinoma↗
PubMed1990

[Experimental study of the effect of combined treatment of UFT with CDDP on human solid tumor-xenografts in nude mice].

The effect of combined treatment of UFT with CDDP, especially the optimal time-dependent administration sequence, was studied in nude mice bearing nine human cancer xenografts derived from stomach, colon, lung, breast and uterocervical cancers following treatment with clinically equivalent doses and routes of administration. This combination treatment produced a higher response rate than a single treatment in 7 out of 9 cancers (78%). However, the combination timing of UFT and CDDP was assumed to be an important factor to produce a good therapeutic effect, since the combination effect was different by changing the treatment procedure, e.g., UFT followed by CDDP or CDDP followed by UFT. There was a low correlation between combination effect and the treatment procedure, origin of tissues, histology and doubling time of cancer cells or efficacy of a single agent. The strongest antitumor effect was observed by the treatment with UFT administered both prior to CDDP and after CDDP. Such treatment procedure seemed to be reasonable for cancers of unknown origin or character.

Animals↗