Biomedical subjects

T Tsuchida

Publications and source records attributed to T Tsuchida.

At least 55 records · Page 3Linked to original sources

PubMed2000

Kinesin is involved in regulation of rat pancreatic amylase secretion.

BACKGROUND & AIMS: Kinesin has recently been localized to zymogen granules of pancreatic acini and is suggested to participate in exocytosis of exocrine pancreas. We examined the function of kinesin in regulated exocytosis of pancreatic acini in this study. METHODS: Kinesin function in exocytosis was examined by introducing hexahistidine-tagged recombinant kinesin protein and antikinesin monoclonal antibody into streptolysin-O-permeabilized acini. Intracellular localization of introduced recombinant kinesin was investigated by immunohistochemistry. Interaction between recombinant kinesin and the microtubule network was confirmed by nocodazole pretreatment of acini. Kinesin regulation by secretagogues was investigated by examining their effect on adenosine triphosphatase (ATPase) activity of endogenous kinesin. RESULTS: Recombinant kinesin enhanced calcium-stimulated amylase release from streptolysin-O-permeabilized acini. Introduced recombinant kinesin was localized to both the microtubule network and zymogen granule. Nocodazole pretreatment of acini abolished the enhancing effect of recombinant kinesin on calcium-stimulated amylase release. Antikinesin antibody inhibited amylase release stimulated by the combination of calcium and cyclic adenosine monophosphate (cAMP) but not that stimulated by calcium alone. Secretin and 8-bromo-cAMP increased ATPase activity of endogenous kinesin. CONCLUSIONS: Kinesin plays a stimulatory role in regulated exocytosis of pancreatic acini and is involved in stimulus-secretion coupling through a cAMP-dependent pathway.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2000

Ribozyme-mediated inactivation of mutant K-ras oncogene in a colon cancer cell line.

Mutation of c-K-ras oncogene is an important step in progression of colon cancer. We used a hammerhead ribozyme (KrasRz) against mutated K-ras gene transcripts (codon 12, GTT) to inactivate mutant K-ras function in the colon cancer cell line SW480, harbouring a mutant K-ras gene. The beta-actin promoter-driven KrasRz sequence (pHbeta/KrasRz) was introduced into these cells (SW480/KrasRz), and we evaluated its effects on growth of the colon cancer. The gene expression of angiogenesis-related molecules (vascular endothelial growth factor and thrombospondin) was also estimated in SW480/KrasRz. KrasRz specifically and efficiently cleaved the mutant K-ras mRNA but not wild-type mRNA in vitro. SW480/KrasRz showed decreased growth rate under tissue culture conditions (P< 0.01, Dunnett's test). The xenotransplantability of SW480/KrasRz (XeSW480/KrasRz) was significantly decreased in nude mice (P< 0.05, Fisher's exact test). Tumour volume of the xenografts XeSW480/KrasRz was significantly smaller than that of XeSW480/DisKrasRz (P< 0.01, Dunnett's test). Gene expression of VEGF was suppressed in SW480/KrasRz, while TSP1 gene expression was enhanced. The SW480/KrasRz cells showed apoptosis-related features including nuclear condensation and DNA fragmentation. These results suggested that the hammerhead ribozyme-mediated inactivation of the mutated K-ras mRNA induced growth suppression, apoptosis and alteration of angiogenic factor expression.

Animals↗

PubMed2000

Clinicopathological studies of esophageal carcinosarcoma: analyses of its morphological characteristics using endoscopic, histological, and immunohistochemical procedures.

BACKGROUND AND STUDY AIMS: Carcinosarcoma of the esophagus is a rare malignant neoplasm consisting of both carcinomatous and sarcomatous components, which characteristically forms polypoid tumors. PATIENTS AND METHODS: Seven carcinosarcomas were analyzed using endoscopic, histological, and immunohistochemical procedures. Endoscopically, six of the seven lesions were found to be of the protruding type, while the other one was an ulcerating tumor. RESULTS: In all seven cases, the carcinomatous component consisted of differentiated squamous cell carcinoma, and the sarcomatous component was spindle cell carcinoma. Histological analyses demonstrated that the majority of the protruding tumors consisted of the sarcomatous component, while the ulcerating tumor mainly consisted of squamous cell carcinoma. The Ki-67 (MIB-1) labeling index (LI) of the carcinomatous component (28.2%) did not differ significantly from that of the sarcomatous component (25.5%). The sarcomatous component showed abundant expression of type IV collagen and laminin. CONCLUSIONS: It is conceivable that the carcinomatous and sarcomatous components grow separately from the early stage of the tumors, and that the sarcomatous component forms a protruding tumor mass because it has abundant stroma positive for type IV collagen and laminin.

Aged↗

PubMed2000

Acinar-islet cell tumor of the pancreas: report of a malignant pancreatic composite tumor.

An unusual case of malignant pancreatic composite tumor with both components of acinar cell tumor (ACT) and islet cell tumor (ICT) was investigated histologically, immunohistochemically, and ultrastructurally. The pancreatic tumor with central cyst formation was found on computerized tomographic examination of a 72-year-old man reporting appetite and weight loss. The ACT component was present in the original pancreatic region and the ICT region was adjacent to the ACT. ACT was immunohistochemically positive for pancreatic amylase, whereas ICT had argyrophil tumor cells immunohistochemically positive for chromogranin A. There were several tumor cell nests positive for both pancreatic amylase (acinar differentiation) and chromogranin A (islet differentiation). We speculated that ICT may have arisen from the de-differentiated tumor cells in the ACT after the occurrence of ACT.

Aged↗

PubMed2000

Role of the renin-angiotensin system in drinking of seawater-adapted eels Anguilla japonica: a reevaluation.

The role of ANG II, a potent dipsogenic hormone, in copious drinking of seawater eels was examined. SQ-14225 (SQ), an angiotensin-converting enzyme inhibitor, infused intra-arterially at 0.01-1 microgram. kg(-1). min(-1), depressed drinking and arterial blood pressure in a dose-dependent manner. The inhibition was accompanied by a small decrease in plasma ANG II concentration, which became significant at 1 microgram. kg(-1). min(-1). After the infusate was changed back to the vehicle, the depression of drinking and arterial pressure continued for >2 h, although plasma ANG II concentration rebounded above the level before SQ infusion. By contrast, infusion of anti-ANG II serum (0.01-1 microgram. kg(-1). min(-1)) did not suppress drinking and arterial pressure, although plasma ANG II concentration decreased to undetectable levels. Plasma atrial natriuretic peptide and plasma osmolality, which influence drinking rate in eels, did not change during SQ or antiserum infusions. These results suggest that the renin-angiotensin system plays only a minor role in the vigorous drinking observed in seawater eels. The results also suggest that the antidipsogenic and vasodepressor effects of SQ in seawater eels are not due solely to the inhibition of ANG II formation in plasma.

Adaptation, Physiological↗

PubMed2000

CEA immunohistochemical localization is correlated with growth and metastasis of human gallbladder carcinoma.

Carcinoembryonic antigen (CEA) is a good marker of colorectal cancer. Recent studies have demonstrated that CEA may function as a metastatic potentiator by different pathways; i.e., modulation of immune responses, facilitation of intercellular adhesion and cellular migration. However, expression patterns of CEA have not yet been established in human gallbladder carcinomas. In this study, we examined CEA expression in human gallbladder adenocarcinomas and its clinicopathological significance. CEA immunoreactivity was detected not only in the cancer cells (cytoplasmic type: 63.0%, 34/54) but also in the cancer stroma (stromal type: 29.6%, 16/54). According to TNM classification, 75.0% (30/40) of T2-4 gallbladder cancers showed cytoplasmic CEA, while 28.6% (4/14) of the T1 cancers were cytoplasmic CEA-positive (p<0.05). Stromal CEA expression was detected in 40.0% (16/40) and none (0/14) of the T2-4 and T1 cancers, respectively (p<0.05). Lymph node metastasis was frequently found in the cytoplasmic CEA- and stromal CEA-positive gallbladder cancers (44.1% and 62.5%, respectively). These observations suggested that CEA expression plays important roles in cancer cell growth and metastasis of human gallbladder adenocarcinomas.

Adenocarcinoma↗

PubMed2000

DF3 expression in human gallbladder carcinoma: significance for lymphatic invasion.

DF3 (MUC 1) is a member of a family of high molecular weight glycoproteins. Recent studies have demonstrated that DF3 is expressed in tumors of various human organs, and may function as an anti-adhesion molecule that inhibits cell-to-cell adhesion, inducing tumor metastasis. However, expression patterns of DF3 have not yet been established in human gallbladder carcinomas. In this study, we examined DF3 expression in human gallbladder adenocarcinoma and its clinicopathological significance. DF3 immunoreactivity was detected not only in the cancer cells (cytoplasmic type; 50.0%, 27/54) but also in the cancer stroma (stromal type; 46.3%, 25/54). According to TNM classification, 65.0% (26/40) of T2-4 gallbladder cancers showed cytoplasmic DF3, while 7.1% (1/14) of the T1 cancers were cytoplasmic DF3-positive (p<0.001). Stromal DF3 expression was detected in 62.5% (25/40) and none (0/14) of the T2-4 and T1 cancers, respectively (p<0.001). Lymph node metastasis was frequently found in the cytoplasmic DF3- and stromal DF3-positive gallbladder cancers (59.3% and 60.0%, respectively). These observations suggested that DF3 expression plays important roles in cancer cell growth and metastasis of human gallbladder adenocarcinomas.

Adenocarcinoma↗

PubMed2000

Stromal sialyl Le(a) expression is correlated with vascular invasion of human gallbladder adenocarcinoma.

Sialyl Le(a) antigen (CA19-9), a member of a family of high molecular weight glycoproteins, was originally described as a gastrointestinal- and pancreatic-specific tumor marker. Recent studies have demonstrated that sialyl Lea is a ligand for E-selectin and may play an important role in tumor metastasis. However, expression patterns of sialyl Le(a) have not yet been established in human gallbladder carcinomas. In this study, we examined sialyl Le(a) expression in human gallbladder adenocarcinoma and its clinicopathological significance. Sialyl Le(a) immunoreactivity was detected not only in cancer cells (cytoplasmic type; 68.5%, 37/54) but also in cancer stroma (stromal type; 46.3%, 24/54). According to TNM classification, stromal sialyl Le(a) expression was detected in 60. 0% (24/40) and 7.1% (1/14) of the T2-4 and T1 cancers, respectively (p<0.01). Stromal sialyl Le(a)-positive gallbladder cancers frequently showed lymphatic invasion, venous invasion and lymph node metastasis (62.9%, 62.5% and 70.0%, respectively) (p<0.01). These observations suggested that sialyl Le(a) expression plays important roles in vascular invasion and metastasis of human gallbladder adenocarcinomas.

Adenocarcinoma↗

PubMed2000

Neuropilin-2 expression affects the increased vascularization and is a prognostic factor in osteosarcoma.

Osteosarcoma is a malignant bone tumor characterized by hypervascularity. Neuropilins (NRPs), which is expressed by human tumor cells, is known to be a potent receptor for vascular endothelial growth factor (VEGF). We examined NRPs mRNA expression in 30 osteosarcomas. The osteosarcomas with NRP2 expression (n=24) showed a significantly increased vascularity (P<0.0014, Mann-Whitney U test). Osteosarcomas with NRP2 showed significantly poorer prognosis than those without NRP2 (P=0.016, Wilcoxon's test). These results suggest that NRP acts as a VEGF-amplifier in a paracrine or autocrine manner in the osteosarcoma. NRP2 expression cooperatively promotes angiogenesis and growth in osteosarcomas with VEGF expression.

Bone Neoplasms↗

PubMed2000

The inhibitory effect of cisplatin in combination with irradiation on lung tumor cell growth is due to induction of tumor cell apoptosis.

Chemoradiation is becoming an important method of treatment of advanced lung cancer. Although many studies have demonstrated the efficacy of chemoradiation against lung tumors, the mechanism of its effect is still poorly understood. In this study, we analyzed the combined effect of cisplatin (CDDP) and irradiation on human lung cancer cell lines (PC-9 and Lu 134A) in vitro using MTT assay and isobologram analysis. To study whether the combined effect is due to induction of tumor cell apoptosis, we further quantified the nuclear fragmentation of tumor cells by flow cytometric analysis. Our study revealed that a combination of cisplatin and irradiation had an additive inhibitory effect on both PC-9 (adenocarcinoma) and Lu 134A (small cell carcinoma) tumor cell growth. Cisplatin improved the sensitivity of tumor cells to irradiation. The use of both cisplatin and irradiation doses could be reduced without decreasing the inhibitory effect. The additive inhibitory effect was correlated positively with the levels of tumor cell nuclear fragmentation. We concluded that combination treatment with cisplatin and irradiation is effective against lung tumors, not only small cell carcinoma but also non-small cell carcinoma, and the inhibitory effect was due to induction of tumor cell apoptosis.

Adenocarcinoma↗

PubMed2000

Hammerhead ribozyme specifically inhibits vascular endothelial growth factor gene expression in a human hepatocellular carcinoma cell line.

Hammerhead-type ribozymes are often utilized to suppress the expression of target genes. We evaluated the efficacy of an anti-vascular endothelial growth factor (VEGF) hammerhead-type ribozyme against GUC at exon 1 of the VEGF gene in a cell-free system (in vitro) as well as in the hepatocellular carcinoma cell line HLF (in vivo). The anti-VEGF ribozyme (alphaVRz) specifically cleaved synthetic VEGF RNA substrate, but not other triplet sequences of VEGF RNA substrate in vitro. When the alphaVRz was introduced into HLF cells, the ribozyme suppressed not only VEGF mRNA level but also that of VEGF protein. These results suggest that this ribozyme selectively inhibits VEGF gene expression in human hepatocellular carcinoma cells.

Base Sequence↗

PubMed2000

[Dopamine transporter SPECT in patients with Parkinson's disease].

The major neuropathological feature in Parkinson's disease (PD) is severe degeneration of the dopamine (DA) neurons in the substantia nigra. Dopamine transporter (DAT) is an important protein in the regulation of DA neurotransmission. It has been reported that PD patients show a loss of DAT in striatum. We report here the findings of single photon emission computed tomography (SPECT) of the DAT with 2 beta-carboxymethoxy-3 beta-(4[123I]iodophenyl)tropane ([123I] beta-CIT) to investigate striatal DAT in 10 patients with PD, one patient with vascular parkinsonism (VP), and one patient with dystonia syndrome. Patients were evaluated using the Webster rating scale. Specific/nondisplaceable striatal binding ratio (V3") was obtained in each case. In PD patients, the uptake of [123I] beta-CIT was reduced, especially in the tail of putamen compared with caudate nucleus. Even in the early stage of PD, the uptake of beta-CIT was reduced not only in the severely affected side, but also in the mildly disturbed side of the brain. Putamen caudate ratio was generally low in PD patients. In VP patient, the uptake was reduced, but putamen caudate ratio was not decreased. V3" values showed significant correlation with the severity of clinical symptoms such as self-care, facies, posture, gait, speech, and Hoehn-Yahr's stage. On the other hand, V3" values were not significantly correlated with the degree of tremor, seborrhea, and duration of the illness. In conclusion, we found that SPECT of the [123I] beta-CIT is a useful method for the diagnosis in the patients presenting parkinsonism, and for the clinico-physiological estimation of parkinsonian symptoms such as self-care, facies, posture, gait, and speech.

Adult↗

PubMed2000

[Bronchofiberscopy].

New diagnostic modalities have been used in conjunction with endoscopy for early detection of lung cancer. Videoendoscope is routinely used instead of fiberoptic bronchoscope. Fluorescence diagnosis has been proved to be useful in detecting subtle lesions which might be invisible by conventional endoscopy in central airway. Also, a number of small peripheral lesions has increased by the helical CT. CT guided transbronchial lung as well as needle cytology are indicated for definitive diagnosis of such lesions. Endobronchial Ultrasonography is employed to evaluate the depth of cancer invasion of the bronchus and lymph node swelling around the bronchus. It should be helpful in staging of lung cancer and selecting therapy.

Bronchoscopy↗

PubMed2000

Evaluation of brain metabolism in steno-occlusive carotid artery disease by proton MR spectroscopy: a correlative study with oxygen metabolism by PET.

UNLABELLED: Carotid occlusive diseases may cause ischemic changes in both the gray matter and the white matter as a result of hemodynamic compromise. To validate the use of proton magnetic resonance spectroscopy (MRS) in evaluating the carotid occlusive diseases, we compared changes in peaks of choline, in the sum of creatine and phosphocreatine, and in N-acetyl-aspartate (NAA) of the white matter with cortical oxygen metabolism measured by PET. METHODS: Eleven patients with unilateral steno-occlusive carotid artery disease underwent PET and MRS. Ten age-matched healthy volunteers underwent MRS. No subjects had cortical infarction. MRS was performed bilaterally in the centrum semiovale. Regional blood flow, regional metabolic rate of oxygen (rCMRO2), and regional oxygen extraction fraction (rOEF) of the cerebral cortex were measured by the steady-state method with 15O gas. RESULTS: The asymmetry index of the ratio of NAA to the sum of creatine and phosphocreatine (NAA/Cr) correlated positively with the asymmetry index of rCMRO2 (r = 0.77; P < 0.01). Because rCMRO2 is a marker of tissue viability, the NAA/Cr of the centrum semiovale may reflect viable neuronal cells. The asymmetry index of the ratio of choline to the sum of creatine and phosphocreatine (Cho/Cr) showed a significant positive correlation with the asymmetry index of rOEF (r = 0.65; P < 0.05). All but 1 patient with an increased Cho/Cr (>1.03) showed an increase in rOEF of the ipsilateral cortex (>0.56). This finding may indicate membrane damage caused by ischemia, because the centrum semiovale is the deep watershed zone. CONCLUSION: The metabolic changes in the centrum semiovale detected by proton MRS reflect a hemodynamically compromised state and are useful in evaluating tissue viability.

Aged↗

PubMed2000

Normal patterns on 99mTc-ECD brain SPECT scans in adults.

UNLABELLED: Normative ethyl cysteinate dimer (ECD) SPECT data must be available to successfully apply ECD SPECT to clinical studies. The purpose of this study was to determine ECD SPECT scan patterns of healthy adults. METHODS: Forty-eight healthy volunteers (22 men, 26 women; age range, 22-95 y; mean age, 47.6 +/- 19.2 y) underwent high-resolution ECD SPECT. For visual analysis of regional brain ECD uptake, we used a scale of +3 to -3, in which +3 and -3 indicated highest ECD uptake and deficit, respectively. For quantitative analysis, we measured the region-to-cerebellum ratio (R/CE) and the region-to-cerebral cortex ratio (R/CO) for 17 regions (13 cortical, 3 subcortical, and 1 cerebellar). RESULTS: On visual analysis, no subject had a score of -3. All subjects had a score of -2 for the hippocampus and a score of +3 for the medial occipital cortex, except for 2 subjects who had a score of +3 for the striatum and thalamus. A frontal eye field and posterior parieto-occipital junction were identified in 60% of subjects with a score of +1 and 79% of subjects with a score of +2. On quantitative analysis, a significant regional variation (ANOVA, P < 0.0001) was seen in R/CE, ranging from 0.709 (hippocampus) to 1.26 (medial occipital cortex). However, regional right-to-left differences and intersubject variability of R/CE were small (asymmetry index, 3.6% +/- 0.8%; coefficient variation, 6.6% +/- 0.7%). R/CE declined significantly with age in 6 regions, including the anterior and posterior cingulate cortex, superior prefrontal and parietal cortex, striatum, and hippocampus (1.0%-2.0% per decade, P < 0.05), whereas R/CO in the cerebellum increased significantly with age (1.0% per decade, P < 0.05). CONCLUSION: Although regional ECD brain perfusion patterns vary significantly, including variability caused by the age-related effect, intersubject variability is small. Recognition of these normal patterns is important for clinical interpretation of ECD SPECT studies.

Adult↗

PubMed2000

Noninvasive estimation of FDG input function for quantification of cerebral metabolic rate of glucose: optimization and multicenter evaluation.

UNLABELLED: The aims of this study were to determine whether body weight or body surface area (BSA) should be used for noninvasive measurement of the cerebral metabolic rate of glucose (CMRGlc) by FDG PET with a standardized input function (SIF) and an autoradiographic method and to validate the procedure in a large population from different PET centers. METHODS: Plasma input functions measured by intermittent arterial blood sampling after intravenous injection of FDG, in 101 patients from 1 institution who were fasting for at least 4 h, were used to generate the SIF. The SIF was generated by averaging over 101 patients the input function normalized with the net injected dose and initial distribution volume (DV) of FDG estimated by the formula c x Ha x Wb, where H is body height and W is body weight. To evaluate the estimation of DV by BSA or body weight, the coefficient of variation (CV) of the ratio of Ha x Wb to the measured DV was calculated by changing a and b independently. Estimation of the CMRGlc with SIF based on the formula for DV was validated with an additional 192 subjects from 3 institutions who underwent FDG PET while fasting. The result of simulation was compared with the results of 4 previously published formulas for BSA and body weight. RESULTS: The optimal set of parameters, in which a was 0.80 and b was 0.35, minimized the CV. The averaged percentage error of the CMRGlc based on the optimal set of parameters for DV estimation and SIF was 8.9% for gray matter and 10.6% for white matter. Four BSA formulas brought about a similar error, which was significantly smaller than that based on body weight (P < 0.001, ANOVA). CONCLUSION: Noninvasive estimation of CMRGlc is made possible by careful measurement of the net injected dose and BSA.

Autoradiography↗

PubMed1999

Study of the relation between fluid distribution change in tissue and impedance change during hemodialysis by frequency characteristics of the flowing blood.

Erythrocyte orientation and deformation cause differences in impedance between flowing and resting blood. Through theoretical calculation and experimental measurements, we studied the effects of these factors on blood impedance. The size and shape of the erythrocyte and the conductivity of the interior medium of the erythrocyte change when the osmotic pressure of plasma is changed. From experimental results, we obtained the following: when the size of the erythrocyte becomes larger than the normal size due to the osmotic pressure change, the beta dispersion frequency decreases and the intra- and extracellular fluid resistance increase. These experimental results corroborate that the change of tissue impedance like muscle impedance during hemodialysis is caused by the change of the fluid distribution and the change of ionic concentration of the electrolyte in tissues during hemodialysis. Also, we could estimate the relative change value of the intra- and extracellular fluid volume by the impedance method, if there were no ionic concentration change in the electrolyte. It would be very difficult to estimate the absolute change value of them because a shadow effect due to the cells depends greatly upon the shape and size of the cells and the cell concentration.

Anisotropy↗

PubMed1999

Enhancement of cellulose production by expression of sucrose synthase in Acetobacter xylinum.

Higher plants efficiently conserve energy ATP in cellulose biosynthesis by expression of sucrose synthase, in which the high free energy between glucose and fructose in sucrose can be conserved and used for the synthesis of UDP-glucose. A mixture of sucrose synthase and bacterial cellulose synthase proceeded to form UDP-glucose from sucrose plus UDP and to synthesize 1,4-beta-glucan from the sugar nucleotide. The mutant sucrose synthase, which mimics phosphorylated sucrose synthase, enhanced the reaction efficiency (Vmax/Km) on 1,4-beta-glucan synthesis, in which the incorporation of glucose from sucrose was increased at low concentrations of UDP. Because UDP formed after glucosyl transfer can be directly recycled with sucrose synthase, UDP-glucose formed appears to show high turnover with cellulose synthase in the coupled reaction. The expression of sucrose synthase in Acetobacter xylinum not only changed sucrose metabolism but also enhanced cellulose production, in which UDP-glucose was efficiently formed from sucrose. Although the level of UDP-glucose in the transformant with mutant sucrose synthase cDNA was only 1.6-fold higher than that in plasmid-free cells, the level of UDP was markedly decreased in the transformant. The results show that sucrose synthase serves to channel carbon directly from sucrose to cellulose and recycles UDP, which prevents UDP build-up in cellulose biosynthesis.

Journal Article↗