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T Osada

Publications and source records attributed to T Osada.

At least 37 records · Page 2Linked to original sources
PubMed2000

Expression of platelet-derived endothelial cell growth factor correlates with good prognosis in patients with colorectal carcinoma.

BACKGROUND: Platelet-derived endothelial cell growth factor (PD-ECGF) is an angiogenic factor that has potent chemotactic activity for endothelial cells. Although it is expressed in the majority of colorectal tumors, and some reports suggest that its high expression is related to poor prognosis, to the authors' knowledge there is yet no consensus regarding whether PD-ECGF expression is a prognostic factor. To investigate the prognostic value of PD-ECGF and its role in tumor angiogenesis, an immunohistochemical study of PD-ECGF expression and tumor vasculature was performed and their relation with the clinicopathologic factors in patients with advanced colorectal carcinoma was evaluated. METHODS: Formalin fixed, paraffin embedded specimens from 86 colorectal carcinoma patients (40 cases in the muscularis propria and 46 cases in the subserosa) were immunostained for PD-ECGF and CD31 as a marker for vascular endothelial cells and expression of PD-ECGF was evaluated using an image analysis system. Patients were divided into high expression and low expression groups based on PD-ECGF expression, and were divided into high vascular grade and low vascular grade groups based on the microvessel density. Correlations between PD-ECGF expression and vascular grade and between PD-ECGF expression,vascular grade, and the clinicopathologic features of the patients were evaluated statistically. RESULTS: PD-ECGF expression was observed predominantly in the tumor stroma and not in tumor cells. The cells that stained strongly for PD-ECGF were confirmed to be macrophages infiltrating the interstitial tissue of the tumor. High PD-ECGF expression was found in 56 cases (65.1%) and low expression was detected in 30 cases (34.9%). Thirty-one of 86 tumors (36.0%) showed high vascular grade and 55 (64.0%) showed low vascular grade. No correlation between PD-ECGF expression and vascular grade was found, but there was an inverse correlation between PD-ECGF expression and the rate of incidence of lymph node and hematogenous metastasis. These correlations were statistically significant. Vascular grade was not found to correlate with the clinicopathologic features. CONCLUSIONS: Patients with high PD-ECGF expression had a lower rate of incidence of lymphatic and hematogenous metastasis, with a consequently better prognosis than patients with low PD-ECGF expression. PD-ECGF expression did not correlate with vascular grade, suggesting that PD-ECGF plays little role in tumor angiogenesis of colorectal carcinoma. Based on these data, the authors conclude that macrophages infiltrating the tumor stroma produce PD-ECGF and play important roles in the immune reaction against the tumor rather than in tumor angiogenesis.

Adult↗
PubMed2000

Distribution and serum concentration of sisomicin released from fibrin glue-sealed dacron graft in the rat and human.

We investigated whether or not fibrin glue (FG) used as a sealant in vascular prostheses to prevent leakage might be useful as a carrier of antibiotics for the prevention of local graft infection. Sisomicin (SISO) was incorporated into fibrin glue (SISO-FG) and evaluated as to its safety and pharmacokinetics. SISO (1.75 mg) -FG Dacron grafts were implanted subcutaneously in the anterior abdominal region of Sprague-Dawley rats, and then the changes in SISO concentrations in the serum and in the tissue around the implantation sites were compared with those same sites in rats that had had intravenous injection of SISO (1.75 mg). The serum SISO concentrations were significantly lower in the SISO-FG Dacron graft group than they were in the intravenous injection group. However, until 4 h after implantation the SISO concentrations in the tissues around the implantation sites were significantly higher in the SISO-FG Dacron group than they were in the iv injection group, and the peak concentrations during that time were 5.8 times higher for the SISO-FG Dacron group than they were for the intravenous injection group. The ratio of the area under the tissue concentration time curve of SISO (AUC tissue) after implantation of the SISO-FG Dacron graft to that after intravenous injection of SISO was 13.08. Therefore, FG was considered to control the release of SISO into the serum and to maintain a high SISO concentration in the tissue around the implantation site. Clinically, SISO (45 mg) -FG was applied directly to the Dacron grafts implanted in 10 patients who underwent prosthetic vascular reconstruction. No graft infection was observed in any of the patients who received SISO-FG Dacron grafts. The mean serum concentration of SISO was 0.65+/-0.17 microg/mL after 1 h and 0.33+/- 0.21 microg/mL after 3 h. The results of these clinical applications are in close correlation with those of the animal experiment and suggest that FG is useful as a carrier of SISO, allowing its controlled release for the prevention of local infection.

Aged↗
PubMed2000

Prognostic significance of glutamine synthetase expression in unifocal advanced hepatocellular carcinoma.

BACKGROUND/AIMS: Glutamine synthetase (GS) catalyzes the synthesis of glutamine, a major energy source of cells, and is upregulated in a subset of human hepatocellular carcinomas (HCCs). GS expression may be related to tumor recurrence, since GS-expressing tumors have a growth advantage in that they are independent of the extracellular glutamine supply. However, there are no studies concerning the prognostic value of GS expression in patients with HCC. METHODS: Seventy-three patients with a single advanced HCC nodule who underwent curative hepatectomy were included in the study. GS expression in the HCC nodules was analyzed immunohistochemically and was compared with clinicopathologic features and the behavior of the tumors. Survival curves were assessed according to the Kaplan-Meier product-limit method and multivariate analysis based on the Cox regression model was performed. RESULTS: GS expression was strong in 26 cases (35.6%, high-GS group) and weak or absent in 47 cases (64.4%, low-GS group). Univariate analysis showed that the high-GS group had a significantly shorter disease-free survival time than the low-GS group (p=0.042). Multivariate analysis revealed that GS expression (p=0.021), as well as Child's classification (p=0.005) and portal invasion (p=0.039), was a significant and independent prognostic parameter that affected tumor recurrence. CONCLUSION: The results of this study indicate that GS expression may enhance the metastatic potential in HCC, and GS immunostaining may be helpful in identifying HCC patients at high risk for disease recurrence.

Adult↗
PubMed2000

E-selectin can mediate the arrest type of adhesion of colon cancer cells under physiological shear flow.

The aim of this study was to determine whether colon cancer cells flowing in blood exhibit the same adhesion pattern to the vascular bed as leucocytes using a flow adhesion system. In shear flow conditions, five colon cancer cell lines showed less tethering to E-selectin substrates than polymorphonuclear cells (PMN). However, some of the Colo201 cells formed complete arrest on E-selectin in continuous shear flow which was never observed in PMN cells. Colo201 cells expressed both sialyl Le-x and sialyl Le-a at similar levels in flow cytometry. However, the staining pattern showed marked contrast under the fluorescein microscope. The cell membrane of Colo201 cells was uniformly stained with anti-sialyl Le-a MAb, whereas anti-sialyl Le-x MAb only stained in the patchy areas. Pretreatment of Colo201 cells with anti-sLe-a decreased tethering, while anti-sLe-x significantly inhibited the arrest formation. Our data suggest that E-selectin alone can mediate colon cancer cell lodgement and subsequent metastasis without the contribution of integrin molecules and that the different distribution of E-selectin ligands may affect the adhesion behaviour of colon cancer cells in flow conditions.

Cell Adhesion↗
PubMed2000

Implications of mechanical stretch on wound repair of gastric smooth muscle cells in vitro.

Gastric smooth muscle cells continually receive repetitive physical stretching by food storage, peristalsis and fasting contraction; therefore mechanical stretch can not be disregarded in gastric events. The aim of this study was to clarify the effects of mechanical stretch on wound repair using a rabbit gastric smooth muscle cell sheet. Mechanical stretch was imposed on adherent cells on a flexible membrane in order to increase elongation by an average of 5% and 10%, respectively, at 5 cycles per minute after artificial wounding. Adherent cells not subjected to mechanical stretch served as controls. The restoration process was monitored by measuring wound size for 48 h. Proliferation was assessed by BrdU staining and the influence on the cytoskeletal system was assessed by actin staining. The speed of restoration was highest in controls and lowest in the 10% stretch groups. Proliferation was almost equal to that of controls in the stretch groups. Under the condition of mechanical stretch, stress fibers appeared weakened and the direction of fibers was not consistent but random. In conclusion, mechanical stretch inhibited the migration of gastric smooth muscle cells, leading to cytoskeletal dysfunction. It is suggested that physical stretch, such as mechanical stretch, might be an important factor in the process of gastric wound repair.

Animals↗
PubMed2000

Effects of growth factors on aspirin-induced inhibition of wound repair in a rabbit gastric epithelial cell model.

BACKGROUND: Aspirin is known to cause adverse effects, including gastric mucosal injury, and to retard gastric wound healing. Growth factors including hepatocyte growth factor (HGF), epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) have been shown to play an important role in the repair of gastric mucosal injury. AIM: To employ the cultured gastric epithelial cell model to elucidate the effects of aspirin, as well as several growth factors (HGF, EGF and IGF-I), on gastric wound repair. METHODS: Isolated rabbit gastric epithelial cells (92% mucous cells) were cultured in F-12 medium and formed a complete monolayer cell sheet in 48 h. A wound with a cell-free area of constant size (2 mm2) was then created and the wound repair process was monitored by measuring wound size every 12 h. Proliferating cells were detected by BrdU staining. Effects of aspirin (8 mM), HGF (10 ng/mL), EGF (10 ng/mL) and IGF-I (30 ng/mL) were assessed. RESULTS: Aspirin significantly retarded wound healing, but simultaneous addition of growth factors significantly accelerated wound repair compared with aspirin alone. Growth factors reversed the aspirin-induced inhibition of cell proliferation. CONCLUSION: Growth factors, including HGF, EGF and IGF-I, reversed the aspirin-induced inhibition of wound repair through their cytoprotective effects on gastric epithelial cells.

Animals↗
PubMed2000

Cyclooxygenase-2 overexpression correlates with tumour recurrence, especially haematogenous metastasis, of colorectal cancer.

Epidemiological studies have demonstrated that nonsteroidal anti-inflammatory drugs (NSAIDs), known to inhibit cyclooxygenase (COX), reduce the risk of colorectal cancer. COX is a key enzyme in prostaglandin biosynthesis, and two isoforms of COX, COX-1 and COX-2, have been identified. Recently COX-2 has been reported to frequently overexpress in colorectal neoplasms and to play a role in colorectal tumorigenesis and tumour progression. In this study, using immunohistochemistry, we examined COX-2 expression in advanced human colorectal cancer and its correlation with clinicopathological features. COX-2 expression was observed mainly in the cytoplasm of cancer cells in all the specimens examined, but some stromal cells and endothelial cells were also stained. According to the grade of COX-2 expression of the cancer cells, patients were divided into high- and low-COX-2 expression groups. High-COX-2 expression significantly correlated with tumour recurrence, especially haematogenous metastasis. These results suggest that a selective COX-2 inhibitor can be a novel class of therapeutic agents not only for tumorigenesis but also for haematogenous metastasis of colorectal cancer. To our knowledge, this is the first report on the correlation between COX-2 overexpression and recurrence of colorectal cancer.

Aged↗
PubMed2000

Effects of epinephrine and lactate on the increase in oxygen consumption of nonexercising skeletal muscle after aerobic exercise.

The purpose of this study was to measure O2 consumption of nonexercising skeletal muscles (VO2nonex) at rest and after aerobic exercise and to investigate the stimulant factors of O2 consumption. In experiment 1, we measured the resting metabolic rate of the finger flexor muscles in seven healthy males by 31P-magnetic resonance spectroscopy during a 15 min arterial occlusion. In experiment 2, the VO2nonex of the finger flexor muscles was measured using near infrared continuous wave spectroscopy at rest, immediate postexercise, and 3, 5, 10, 15, and 20 min following a cycling exercise at a workload corresponding to 50% of peak pulmonary O2 uptake for 20 min. We also monitored deep tissue temperature in the VO2nonex measurement area and determined catecholamines and lactate concentrations in the blood at rest and immediate postexercise. VO2nonex at rest was 1.1 +/- 0.1 microM O2/S (mean +/- standard error) and VO2nonex after exercise increased 59.6 +/- 7.2% (p < 0.001) from the resting values. There were significant correlations between the increase in VO2nonex and the increase in epinephrine concentration (p < 0.01), and between the increase in VO2nonex and the increase in lactate concentration (p < 0.05). These results suggest that epinephrine and lactate concentrations are important VO2nonex stimulant factors.

Adult↗
PubMed2000

Quantification of ischemic muscle deoxygenation by near infrared time-resolved spectroscopy.

The purpose of this study was to quantify muscle deoxygenation in human skeletal muscles using near infrared time-resolved spectroscopy (NIRTRS) and compare NIRTRS indicators and blood saturation. The forearm muscles of five healthy males (aged 27-32 yrs.) were monitored for changes in hemoglobin saturation (SO2) during 12 min of arterial occlusion and recovery. SO2 was determined by measuring the temporal profile of photon diffusion at 780 and 830 nm using NIRTRS, and was defined as SO2-TRS. Venous blood samples were also obtained for measurements of SvO2, and PvO2. Interstitial PO2(PintO2) was monitored by placing an O2 electrode directly into the muscle tissue. Upon the initiation of occlusion, all parameters fell progressively until reaching a plateau in the latter half of occlusion. It was observed at the end of occlusion that SO2-TRS (24.1 +/- 5.6%) agreed with SvO2 (26.2 +/- 6.4) and that PintO2 (14.7 +/- 1.0 Torr) agreed with PvO2 (17.3 +/- 2.2 Torr). The resting O2 store (oxygenated hemoglobin) and O2 consumption rate were 290 microM and 0.82 microM s-1, respectively, values which reasonably agree with the reported results. These results indicate that there was no O2 gradient between vessels and interstisium at the end of occlusion.

Adult↗
PubMed2000

MMP-1 is a prognostic marker for hematogenous metastasis of colorectal cancer.

BACKGROUND: Degradation of basement membrane and extracellular matrix by matrix metalloproteinases (MMPs) is believed to be an essential step in the complicated process of hematogenous metastasis. MMP-1 is a member of collagenases, a family of MMPs that degrades collagens type I, II, and III, main components of the interstitial stroma. The purpose of this study was to investigate the expression of MMP-1 in colorectal cancer and its correlation with hematogenous metastasis. Patients and Methods. We examined 133 cases of colorectal cancer (Dukes A: 72; Dukes B: 26; Dukes C: 23; Dukes D: 12). Sections were cut from formalin-fixed, paraffin-embedded samples containing the deepest site of cancer invasion and stained immunohistochemically with a monoclonal antibody to MMP-1. According to the area of the tumor that was stained, patients were divided into high- and low-MMP-1 expression groups. RESULTS: MMP-1 expression was observed in the cytoplasm of cancer cells, some stromal cells, and a few normal epithelial cells of colonic mucosa. High MMP-1 expression was found in 47 (35.3%) cases and low in 86 (64.7%). Hematogenous metastasis was identified in 14 (29.8%) of high-MMP-1 groups and 12 (13.9%) of low-MMP-1 groups. MMP-1 expression significantly correlated with hematogenous metastasis of colorectal cancer, but no correlation was found between MMP-1 expression and the other clinicopathological features investigated. CONCLUSIONS: MMP-1 expression may be a novel marker for hematogenous metastasis of colorectal cancer, and its inhibition may be a strategy for prevention of metastasis.

Adult↗
PubMed1999

The expressed localization of rat putative pheromone receptors.

The localization of pheromone receptors in the rat vomeronasal epithelium was examined by light- and electron-microscopic immunocytochemical analysis, using affinity-purified polyclonal antibodies. The antibodies were raised against a synthetic oligopeptide corresponding to a partial sequence of the rat putative pheromone receptor (VN6). Positive immunoreactivity was observed on the luminal surface of the sensory epithelium, and was abolished when an excess of the antigen peptide was added to the primary reaction solution. On electron microscopy, the immunoreactivity for the VN6 peptide was localized at the dendritic knobs and microvilli of receptor cells, but not in those of the supporting cells. These results show the first evidence of cellular localization of putative pheromone receptors in rat vomeronasal receptor cells.

Animals↗
PubMed1999

Increased anxiety and impaired pain response in puromycin-sensitive aminopeptidase gene-deficient mice obtained by a mouse gene-trap method.

A mouse mutation, termed goku, was generated by a gene-trap strategy. goku homozygous mice showed dwarfism, a marked increase in anxiety, and an analgesic effect. Molecular analysis indicated that the mutated gene encodes a puromycin-sensitive aminopeptidase (Psa; EC 3. 4.11.14), whose functions in vivo are unknown. Transcriptional arrest of the Psa gene and a drastic decrease of aminopeptidase activity indicated that the function of Psa is disrupted in homozygous mice. Together with the finding that the Psa gene is strongly expressed in the brain, especially in the striatum and hippocampus, these results suggest that the Psa gene is required for normal growth and the behavior associated with anxiety and pain.

Aminopeptidases↗
PubMed1999

Acquisition of glutamine synthetase expression in human hepatocarcinogenesis: relation to disease recurrence and possible regulation by ubiquitin-dependent proteolysis.

BACKGROUND: The authors previously reported increased ubiquitin (Ub) immunoreactivity in hepatocellular carcinomas (HCCs) and suggested a possible correlation between changes in ubiquitinated protein levels and multistep hepatocarcinogenesis. The current study was performed to identify one of these ubiquitinated proteins (42 kDa) and to analyze the clinical significance of its accumulation. METHODS: The protein was purified using two-dimensional gel electrophoresis and identified by amino acid sequence analysis. The authors studied the expression of this protein in 101 HCCs and 23 precancerous lesions by immunohistochemical methods and in 26 HCCs by immunoblot analysis. A survival analysis was performed on patients with advanced HCC using the Kaplan-Meier method with approximate chi-square statistics for the log rank test. RESULTS: The target protein for ubiquitination was identified as glutamine synthetase (GS). Accumulation of GS was found in 19 of 49 advanced HCCs (38.8%) by immunohistochemical methods and in 9 of 16 (56.3%) by immunoblot analysis, whereas the frequency was much lower in early HCCs (12.9% and 33.3%, respectively) and precancerous lesions (4.3% by immunostaining). In the Ub immunoblot analysis of strongly GS positive specimens, an intense 42-kDa ubiquitinated band was observed. Nine of 21 (42.9%) nodule-in-nodule type HCCs showed a GS positive, high-grade component within a GS negative, low-grade component, indicating the acquisition of GS expression during progression. Among 23 patients with a single advanced HCC nodule, the relapse free survival time was significantly shorter in the GS positive group than in the GS negative group. CONCLUSIONS: The results of this study demonstrate the acquisition of GS expression during hepatocarcinogenesis and the possible regulation of GS enzyme activity by a Ub-dependent proteolytic system. Moreover, GS might play a significant role in promoting the metastatic potential of HCC.

Amino Acid Sequence↗
PubMed1999

CD8(+)NKR-P1A (+)T cells preferentially accumulate in human liver.

A unique subset of T cells that co-express NKR-P1, which is a lectin type of NK receptor and is thought to have a major role in triggering NK activity, has been identified. In mice, NK1.1 (mouse NKR-P1C)(+) T cells, called NKT cells, preferentially accumulate in the liver and bone marrow. They predominantly use invariant Valpha14 chain TCR and phenotypically are CD4(+)CD8(-) or CD4(-)CD8(-) T cells. In this study, we analyzed, phenotypically and functionally, the NKR-P1A (analogue of murine NKR-P1C)(+) T cells resident in the human liver. Here, we show that in complete contrast to the NKT cells in the mouse liver, the majority of NKR-P1A(+) T cells in the human liver are CD8(+) and their TCR repertoire is not skewed to Valpha24 TCR, the homologue of murine Valpha14 TCR. Almost all of the NKR-P1A(+) T cells in the human liver expressed CD69, suggesting that they were activated. Furthermore, the NKR-P1A(+) T cells in the human liver exhibited strong cytotoxicity against a variety of tumor cell lines including K562, Molt4 and some colonic adenocarcinoma cell lines.

Adenocarcinoma↗
PubMed1999

A developmental study using three antibodies (VOBM1, VOBM2, and VOM2): immunocytochemical and electron microscopical analysis of the luminal surface of the rat vomeronasal sensory epithelium.

The development of the rat vomeronasal organ was studied morphologically and immunocytochemically, using the monoclonal antibodies (MAbs) VOBM1, VOBM2 and VOM2 that react with the luminal surface of the vomeronasal sensory epithelium. Postnatal day (P) 7, 14, 21, 28, 35 and adult animals were examined. The vomeronasal organ and the blood vessel of the organ markedly increased in size and the vomeronasal glands increased in number between P7 and P14. At P35, the shape of the vomeronasal organ was similar to that of the adult but its size was slightly smaller. Electron microscopy showed that only a few scattered microvilli were present on supporting cells, and receptor cells were immature at P7. At P21, well-branched microvilli of the receptor cells and many microvilli of the supporting cells were observed on the luminal surface of the sensory epithelium. At P35, most apical endings of supporting cells and receptor cells were covered with numerous microvilli. Less developed areas were also present at the luminal surface of the epithelium at P35. At P7, immunoreactivities of the three antibodies were observed as discontinuous thin-layered bands only on the luminal surface of the sensory epithelium and no immunoreactivity was observed in other regions of the vomeronasal organ. Immunoreactivities of the VOBM1, VOBM2 and VOM2 increased with age and were observed as continuous thin-layered bands on the luminal surface of the epithelium by P35. These finding suggest that the development of the vomeronasal organ continues after birth and that the organ may reach maturity just before puberty (P42-49).

Animals↗
PubMed1999

Laminin mediates tethering and spreading of colon cancer cells in physiological shear flow.

Under the physiological shear condition, cultured colon cancer cells bound to laminin (LM), but not to fibronectin or vitronectin. Most of the tethered cells did not roll, but arrested immediately and spread within 10-30 min on LM under the continuous presence of shear flow. The tethering of Colo201 was partially inhibited by monoclonal antibodies (mAbs) to alpha6 integrin and a combination of mAbs to beta1 and beta4 integrins, but not by mAb to 67KD laminin receptor. Some Colo201 cells still tethered at 4 degrees C. This suggests that alpha6beta1 and alpha6beta4 integrins participate in Colo201 tethering on LM, although other non-integrin molecules play roles. In contrast, the spread of Colo201 was effectively inhibited by the mAbs to integrin alpha2, alpha6 and beta1 chains. The effect of anti-alpha2 plus anti-alpha6 mAbs was almost equal to anti-beta1, suggesting that Colo201 cells mainly use alpha2beta1 and alpha6beta1 integrins for spreading on LM. When the cells were perfused on subconfluent endothelial cells (HUVEC) cultured on LM, they did not tether on HUVEC but did on coated LM exposed at intercellular gap area. Immunohistochemistry revealed that LM abundantly existed in the cytosol of human portal and hepatic vein endothelial cells. These data suggest that LM can mediate from tethering to spreading of colon cancer cells under the blood flow and plays an essential role in haematogeneous metastasis.

Antibodies, Monoclonal↗
PubMed1999

Inhibition of haematogenous metastasis of colon cancer in mice by a selective COX-2 inhibitor, JTE-522.

It is proposed that non-steroidal anti-inflammatory drugs (NSAIDs) reduce colorectal tumorigenesis by inhibition of cyclooxygenase (COX). COX is a key enzyme in the conversion of arachidonic acid to prostaglandins and two isoforms of COX have been characterized, COX-1 and COX-2. Multiple studies have shown that COX-2 is expressed at high levels in colorectal tumours and play a role in colorectal tumorigenesis. Recently it has been reported that selective inhibition of COX-2 inhibits colon cancer cell growth. In this study we investigated the effect of a selective COX-2 inhibitor (JTE-522) on haematogenous metastasis of colon cancer. For this purpose, we selected a murine colon cancer cell line, colon-26, that constitutively expresses the COX-2 protein. The subclone P expressed a high level of COX-2 and the subclone 5 expressed a low level. The colon-26 subclones were injected into the tail vein of BALB/c mice. JTE-522 was given intraperitoneally every day from the day prior to cancer cell injection, and the mice were sacrificed 16 days after cell injection. Lung metastases were compared between groups with and without JTE-522. In the mice injected with subclone P, the number of lung metastatic nodules was significantly reduced in the treated group. However, in the mice injected with subclone 5, there was little difference between the control and the treated groups. These results indicate that there may be a direct link between inhibition of haematogenous metastasis of colon cancer and selective inhibition of COX-2, and that selective COX-2 inhibitors may be a novel class of therapeutic agents not only for colorectal tumorigenesis but also for haematogenous metastasis of colon cancer.

Animals↗