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Biomedical subjects

T Tsuda

Publications and source records attributed to T Tsuda.

At least 451 records · Page 25Linked to original sources
PubMed1989

[Radiation-induced esophageal stricture in patients with non-small cell lung cancer treated with chemoradiotherapy].

Five out of 165 cases (3.0%) which were treated for non-small cell lung cancer with radiotherapy (98 cases were treated with chemoradiotherapy, and the other 67 cases, radiotherapy alone) developed esophageal stricture. Their clinical courses, the relationship among radiation dosage, combination with chemotherapy, the length of the irradiated esophagus, and the occurrence of esophageal stricture were reviewed. One of the 5 cases was a case with lung cancer in Bloom's syndrome, which developed an esophageal stricture after receiving only 30.6 Gy (the TDF value was 46.2) to the esophagus. This case suggests the possibility that a patient with Bloom's syndrome is more radiosensitive than normal controls. The other 4 cases were treated with combined chemoradiotherapy. One of the 4 cases was treated with concomitant use of bleomycin (BLM), while the TDF value was not more than 100 (75.4). The concomitant sue of BLM was almost certainly the cause of the esophageal stricture. The other 3 cases were treated with chemoradiotherapy, the TDF values of which were more than 100 (108.7, 112.5, and 129.3). The chemotherapy combined with radiotherapy and the overdosage were considered to be the cause of the esophageal stricture in these 3 cases. These data suggest that in Bloom's syndrome, radiotherapy should be performed carefully and that BLM should not be used simultaneously with irradiation to the esophagus. It is also believed that a radiation dose over 100 in TDF value to the esophagus should be discouraged when chemotherapy is combined.

Adult↗
PubMed1989

Cyclic nucleotides and GTP analogues stimulate light-induced phosphorylation of octopus rhodopsin.

Light-induced phosphorylation of octopus rhodopsin in microvillar membrane was shown to be stimulated by cyclic nucleotides in contrast to vertebrate rhodopsin kinase. Non-hydrolyzable GTP analogues, GTP lambda S and GppNHp, greatly enhanced the light-induced phosphorylation of octopus rhodopsin, but the non-hydrolyzable GDP analogue, GDP beta S, was not effective. These results suggest that rhodopsin A-kinase is involved in regulating the interaction between rhodopsin and G-protein in octopus photoreceptors.

Animals↗
PubMed1989

Preliminary investigation of ion mobility spectrometry after capillary electrophoretic introduction.

Using standard capillary electrophoretic and ion mobility methods, several electrospray interface designs were investigated for the capillary electrophoretic introduction of samples into the ion mobility spectrometer. Of the interfaces investigated, the flow assisted interface and the direct coupled interface showed the most promise. These preliminary experiments were encouraging. The ion mobility spectrometer coupled with a capillary electrophoretic introduction system operated with excellent separation efficiency and ion mobility reproducibility. Using tetrabutylammonium iodide, the number of theoretical plates for the spectrometer was calculated to be 3.10(3) and reduced mobilities were found to be reproducible with a relative standard deviation of 1.43%. Because of the desire to hold the spectrometer as hot as possible, the solvent would often vaporize in the interface, creating an unstable spray and inhomogeneities in the electrophoretic field. More work is needed to improve the spray process which contributed to the overall noise of the system and to eliminate the phenomenon of solvent vaporization which limited the reproducibility of electrophoretic migration times.

Electrophoresis↗
PubMed1989

High incidence of coamplification of hst-1 and int-2 genes in human esophageal carcinomas.

We analyzed the alteration of the hst-1 and int-2 genes in 36 cases of esophageal squamous cell carcinoma, 42 cases of gastric adenocarcinoma, and 52 cases of colorectal adenocarcinoma. Coamplification of the hst-1 and int-2 genes was observed in 19 of 36 esophageal carcinomas (52%), 16 of 34 primary tumor tissues (47%), and 10 of 10 metastatic tumors (100%). The degree of amplification ranged from 4- to 8-fold. The incidence of hst-1 and int-2 gene coamplification was significantly higher in male patients than that in female patients (P less than 0.05). The coamplification of the hst-1 and int-2 genes had a tendency to correlate with clinical stage. The progesterone receptor gene, which is mapped to chromosome 11 at band q21-23, was not amplified in these esophageal carcinomas. Coamplification of the hst-1 and int-2 gene does not seem to imply increased numbers of chromosome 11, and the hst-1 and int-2 genes appear to be in same amplification unit on chromosome 11 at band q13. No coamplification of the hst-1 and int-2 genes was detected in gastric carcinomas and colorectal carcinomas. These results suggest that amplification of chromosomal locus of the hst-1 and int-2 genes might participate in carcinogenesis, in progression, and particularly in metastasis of esophageal carcinomas.

Blotting, Southern↗
PubMed1989

Identification of a major GTP-binding protein in bovine aortic smooth muscle membranes as smg p21, a GTP-binding protein having the same effector domain as ras p21s.

At least two GTP-binding proteins (G proteins) with Mr values of about 20,000 were extracted from bovine aortic smooth muscle membranes by sodium cholate. The most abundant G protein (22K G) was purified to near homogeneity by successive column chromatographies of Ultrogel AcA-44, phenyl-Sepharose CL-4B, hydroxyapatite and Mono Q HR5/5. 22K G showed kinetic and physical properties very similar to those of smg p21, a G protein recently isolated from bovine brain and human platelet membranes, having the same effector domain as ras p21s. Moreover, 22K G was recognized specifically by the anti-smg p21 antibody. These results indicate that the major G protein in bovine aortic smooth muscle membranes is smg p21.

Animals↗
PubMed1989

Pentylenetetrazole-induced changes of the single potassium channel in primary cultured cerebral cortical neurons.

To elucidate the behavior of the single ionic channels of cerebral cortical neurons during bursting activity, the effects of pentylenetetrazole (PTZ) on a single potassium channel of primary cultured cerebral cortical neurons from mice were examined. All of the examined 10-day-old primary cultured neurons of the cerebral cortex showed clear bursting activity after extracellular application of PTZ using whole-cell patch-clamp recording. Less than half of the examined single potassium channels, both outward and inward, of the 2- and 3-day-old as well as 6-10-day-old primary cultured cerebral cortical neurons showed the bursting-type open-close state by application of PTZ. The PTZ-sensitive single potassium channels were found in the voltage-dependent as well as calcium-activated channels.

Animals↗
PubMed1989

Endothelin stimulates diacylglycerol accumulation and activates protein kinase C in cultured vascular smooth muscle cells.

Endothelin, a novel peptide isolated from the conditioned medium of endothelial cells, causes a slow, sustained contraction of vascular smooth muscle, but its mechanism of action remains unclear. To determine whether the diacylglycerol/protein kinase C signalling pathway is stimulated by endothelin, we exposed cultured rat aortic smooth muscle cells to endothelin and measured diacylglycerol accumulation and protein kinase C-dependent protein phosphorylation. Endothelin stimulated a dose-dependent, biphasic increase in diacylglycerol, which was sustained for at least 20 min. This peptide also induced a prolonged phosphorylation of an acidic protein with a molecular weight of 76,000, which was detectable by 30 s and sustained for at least 20 min. This phosphorylation could be mimicked by phorbol 12-myristate 13-acetate, but not by ionomycin, and was markedly reduced when protein kinase C was down-regulated by a 24-h pretreatment with phorbol 12,13-dibutyrate. These results suggest that endothelin causes a robust stimulation of the diacylglycerol/protein kinase C pathway in cultured vascular smooth muscle cells, and that this mechanism may contribute importantly to the physiologic events stimulated by endothelin in intact blood vessels, including slow, tonic contraction and Ca2+ influx.

Animals↗
PubMed1989

Postischemic changes of calcium and endogenous antagonist in the rat hippocampus studied by proton-induced X-ray emission analysis.

Proton-induced X-ray emission analysis (PIXE) was applied to determine ischemia-induced changes in the content of calcium, iron, nickel and zinc in the rat hippocampus. After 30 min or 2 h reperfusion following 20 min of ischemia, the nickel content decreased and the zinc content increased. The calcium content was increased 50% after 30 min but was normal after 2 h reperfusion.

Animals↗
PubMed1989

Angiotensin II induces c-fos mRNA in aortic smooth muscle. Role of Ca2+ mobilization and protein kinase C activation.

Vasoconstrictors such as angiotensin II (Ang II) play an important role in the pathogenesis of hypertension. These agonists may be responsible for the abnormal vascular smooth muscle cell (VSMC) growth seen in hypertension, either indirectly as a consequence of elevating blood pressure or directly as a result of receptor-mediated effects on VSMC growth. To investigate whether Ang II might directly initiate or modulate some of the "early" genetic programs associated with growth in VSMC, the expression of the proto-oncogene c-fos was studied in cultured rat aortic VSMC. Ang II rapidly induced the accumulation of c-fos mRNA, with maximal levels occurring at approximately 30 min. Induction of c-fos mRNA by Ang II was concentration-dependent, with a maximal response at 100 nM. Ang II induction of c-fos mRNA was blocked by its competitive inhibitor, [sarcosine 1,isoleucine 8]angiotensin II. Induction of c-fos mRNA was not dependent upon Ang II-stimulated intracellular alkalinization or activation of Na+/H+ exchange, but was dependent upon mobilization of intracellular Ca2+ and protein kinase C activation. Epidermal growth factor, a VSMC mitogen, also induced c-fos mRNA in VSMC, but by a mechanism different from that of Ang II. These results demonstrate that the vasoconstrictor hormone Ang II induces in VSMC one of the earliest genes, c-fos, associated with the proliferative response.

Angiotensin II↗
PubMed1989

Identification of secretin diastereoisomers produced during synthesis.

The byproducts P-1 and P-2, which were produced during the synthesis of porcine secretin, were isolated in pure form from the crude secretin by HPLC. These were identified by a combination of amino acid analysis, enzymatic digestion, and isocratic or linear gradient reversed-phase (RP)-HPLC. The amino acid compositions of P1 and P2, determined by amino acid analysis after acid hydrolysis, were found to be the same as those of porcine secretin without distinction between L-and D-amino acids. But, HPLC of their digestive fragments with trypsin and alpha-chymotrypsin differed from that of secretin. The fragments, S7-12 of P-1 and S13-21 of P-2 were determined to be different from the corresponding fragments obtained from secretin by HPLC analysis of their digestive fragments. The amino acid composition of each acid hydrolysate, following digestion with D-amino acid oxidase, was found to have less leucine or alanine content than secretin. The HPLC analysis of the fragments from P-1 and P-2 by tryptic and alpha-chymotryptic digestion showed that they are the same as those from synthetic D-Leu10 secretin or D-Ala17 secretin, respectively. Consequently, P-1 and P-2 are concluded to be the secretin diastereoisomers, D-Leu10 and D-Ala17 secretin, respectively.

Amino Acids↗
PubMed1989

Amplification of epidermal growth factor receptor (EGFR) gene and oncogenes in human gastric carcinomas.

DNAs from 37 human gastric carcinomas and seven lymph node metastases were analyzed for alterations of the epidermal growth factor receptor (EGFR) gene and oncogenes by the Southern blot hybridization method. The probes used were EGFR gene, c-Ha-ras, v-Ki-ras, N-ras, c-myc, v-myb, v-fos, c-erbB-2, v-erbA, v-abl and v-fes. Amplification of the EGFR gene was detected in only one poorly differentiated adenocarcinoma. Amplifications of c-myc gene and c-erbB-2 gene were each observed in two well differentiated adenocarcinomas. One of these tumors had coamplification of c-erbB-2 and c-erbA genes but there were no amplifications nor rearrangements of other oncogenes. The poorly differentiated adenocarcinom with amplified EGFR gene also showed enhanced expression of EGFR gene by Northern blot analysis and additionally had strong synchronous immunoreactivity for EGFR and EGF.

Adenocarcinoma↗
PubMed1989

Quantification of area and percentage of infarcted myocardium by single photon emission computed tomography with thallium-201: a comparison with serial serum CK-MB measurements.

In order to quantify the size of the infarcted myocardium, two kinds of data processing techniques were applied to single photon emission computed tomography (SPECT) with thallium-201 and its clinical reliability was evaluated by comparing it with the infarct sizing procedure with the serial serum creatine kinase-MB measurements in 14 patients with acute myocardial infarction. After maximum-count circumferential profile analysis, short axis images were reformatted into an unfolded surface map and a bull's eye view map. The SPECT-determined infarct size was defined as the area or the percentage of hypoperfused myocardium of which the profile count was less than the mean minus 2SD derived from 8 normal subjects. The infarct area was calculated from the number of pixels with an abnormal count and expressed in an unfolded surface map. The percentage was calculated from the number of abnormal profile points and displayed in a bull's eye view map. A high linear correlation was observed between the enzymatically determined infarct size and the infarct area or the percentage (r = .947, r = .872, respectively), despite underestimations in 2 patients with accompanying right ventricular infarction and overestimations in 2 patients with prior anterior infarction. Moreover, a close negative correlation was found between the left ventricular ejection fraction and the infarct area or the percentage (r = .836, r = .821, respectively). Thus, the semiautomatic techniques for processing thallium-201 SPECT images might contribute to the quantitative estimation and display of infarcted myocardium and have high clinical reliability.

Adult↗
PubMed1989

Availability of 111In-labeled platelet scintigraphy in patients with postinfarction left ventricular aneurysm.

Eighteen patients with postinfarction left ventricular aneurysms (LVAs) were examined with Indium-111-labeled autologous platelet scintigraphy to identify intracardiac thrombi and to investigate the effect of antithrombotic agents on thrombogenesity within their LVAs. Left ventriculography (LVG), and two-dimensional echocardiography were also carried out to assess the diagnostic ability of the platelet imaging. Indium-111-platelet scintigraphy for the detection of LVA mural thrombi had a sensitivity of 60% and a specificity of 100%. Four of six patients with false-negative scintigraphic studies had been under antiplatelet therapy. Eight of the nine patients who had showed active platelet deposition on initial examination had not received antiplatelet therapy. Thereafter, five of these nine were treated with tichlopidine (300 mg/day) for 29.8 +/- 5.0 days. On the second platelet study, two had resolution and the other three had interruption of intra-aneurysmal deposition, which remained positive. In only one patient of the three, the third platelet study was performed after warfarin therapy. It took two weeks after beginning the therapy to completely interrupt platelet deposition within the LVA in this patient. ECG gated radionuclide ventriculography and Thallium-201-myocardial scintigraphy were also performed to assess left ventricular wall motion of left ventricular ejection fraction (LVEF) and myocardial blood perfusion. Thallium-201-SPECT showed apical or anteroapical perfusion defects and the radionuclide ventriculography correctly identified all 18 apical and anteroseptal aneurysms which were confirmed by LVG methods. The comparison between the thrombus positive group and the thrombus negative group was carried out on both the LVEF and the period from the last myocardial infarction to the initial platelet scanning study. There were no statistical differences in the LVEF and the interval (34.5 +/- 12.5% vs 37.3 +/- 14.6%, 39.6 +/- 52.6 days vs 89.6 +/- 108.3 days) between the two groups. These results suggest that Indium-111-labeled platelet scintigraphy can be a reliable method for the identification of active left ventricular mural thrombi and a practical method of judging antiplatelet and anticoagulant therapy.

Adult↗
PubMed1989

Scintigraphic imaging of a case of congenitally corrected transposition of the great vessels and an adult case of single atrium and single ventricle.

We report on the clinical utility of radionuclide angiography and gated blood pool single emission computed tomography (gated blood pool SPECT) in two patients having congenital heart disease. Both conventional equilibrium radionuclide angiography and gated blood pool SPECT demonstrated the connection of the great vessels with both ventricles in a 15-year-old male patient with a congenitally corrected transposition of the great vessels. In particular, the latter procedure could provide very useful information about the ventricular morphology and inversion which is important for diagnosing this disorder. The second case is an extremely rare 42-year-old female patient with a single atrium and single ventricle. She underwent first-pass and multiple gated blood pool angiography from the anterior, right and left oblique views. The combination of these scintigraphic techniques revealed an insufficiency in anatomical correlations among the single atrium, atrioventricular valve, single ventricle and the great vessels in addition to the connection of superior vena cava with the single atrium, and the atrioventricular valve. Thus, conventional equilibrated angiography from multiple views and gated blood pool SPECT seems to be very reliable not only for anatomical evaluation but also for clinical course observation in patients with complicated congenital heart disease.

Abnormalities, Multiple↗
PubMed1989

Assessment of hepatic excretory function in chronic liver disease by hepatobiliary scintigraphy.

Hepatobiliary scintigraphy was performed in 23 normal subjects and 47 patients with chronic liver disease (chronic hepatitis; n = 27, liver cirrhosis; n = 20) to evaluate its availability as a test of liver function. After intravenous administration of Tc-99m N-pyridoxyl-5-methyl-tryptophan, the data were acquired for 60 min and the time-activity curves of ROIs (the heart and liver) were generated. In two compartment model simulation, the early blood clearance rate (kl), late blood clearance rate (km), hepatic uptake rate (ku) hepatic excretion rate (ke), and hepatic excretion T 1/2 were calculated. There was no significant difference in those four k values in normal and chronic hepatitis. However, in liver cirrhosis each of them, except km, was lower than in normal subjects. The kl value correlated closely with the indocyanine green plasma clearance test, whereas the ke and T 1/2 values were closely correlated with the level of serum bilirubins. Only hepatobiliary scintigraphy showed the excretory function of the liver quantitatively and the ke value was helpful in detecting hepatic excretory dysfunction early in chronic liver disease before serum bilirubins increased.

Adolescent↗
PubMed1989

Scleral fibroblasts of the chick embryo proliferate by an autocrine mechanism in protein-free primary cultures: differential secretion of growth factors depending on the growth state.

Scleral fibroblasts of the chick embryo in primary culture proliferated in a protein-free medium. Conditioned medium (CdM) from the culture contained plural growth-promoting factors, which were active to the same cell type. The activity of one of the growth-promoting factors (SAF-I) was heat-resistant and the rest (SAF-II) were heat-sensitive. SAF-I accumulated in the CdM only during the growing phase; on the other hand, SAF-II accumulated in the CdM during the stationary phase. SAF-I showed the same time course of DNA synthesis-promoting activity as human PDGF. However, the activity of the SAF-I was not neutralized by anti-human PDGF. On the other hand, a part of the SAF-II (SAF-II a) showed a strong affinity for heparin.

Animals↗