Biomedical subjects

S Kanda

Publications and source records attributed to S Kanda.

At least 37 records · Page 2Linked to original sources

PubMed2001

Prognostic significance of platelet-derived endothelial cell growth factor/thymidine phosphorylase expression in stage pT1 G3 bladder cancer.

BACKGROUND: The management of patients with pT1 G3 bladder cancer remains controversial because of the high incidence of recurrence with muscle invasion. Thymidine phosphorylase (dThdPase) is identical to platelet-derived endothelial cell growth factor (PD-ECGF) and has angiogenic activity. The aim of this study was to determine whether the expression of PD-ECGF/dThdPase in bladder cancer tissue was associated with tumor progression and recurrence in patients with pT1 G3 bladder cancer. METHODS: Fifteen patients who were pathologically diagnosed as having pT1 G3 transitional cell carcinoma of the bladder were treated with transurethral resection. Sections of paraffin-embedded bladder tissue were immunohistochemically stained with either mAb654-1, a monoclonal antibody against human PD-ECGF or anti-CD34 monoclonal antibody, respectively. When more than 10% of tumor cells were positively stained with mAb654-1, this section was defined as positive in this study. RESULTS: Eight of 15 sections from patients with pT1 G3 bladder cancer (53%) were positive with PD-ECGF/dThdPase. During follow up, patients in the negative group had no disease progression and only two patients had local recurrence. In contrast, seven of eight positives had recurrence (P < 0.05) and progression was also observed in four recurrent patients. However, there was no statistical relationship between PD-ECGF and CD34 expression in any of the patients. CONCLUSION: The expression of PD-ECGF/dThdPase appears to be an important prognostic factor of pT1 G3 bladder cancer and did not show any significant relationship between PD-ECGF/dThdPase expression and vascular density.

Aged↗

PubMed2001

Characterization of the 5' flanking region of the rat D(3) dopamine receptor gene.

The D(3) dopamine receptor has a restricted regional distribution in brain and is regulated by dopaminergic agents. Additionally, the D(3) gene is implicated in the pathogenesis of several neuropsychiatric disorders or in their response to pharmacological agents. Elucidating its transcription control mechanisms is therefore of interest in order to explain these biological features of the D(3) gene. In this study, the 5' flanking region of the rat D(3) gene was characterized by isolating the 5' end of its cDNA as well as 4.6 kb of genomic sequence. Analysis of this region revealed the presence of two new exons 196-bp and 120-bp long, separated by an 855-bp intron, located several kilobases upstream of the previously published coding exons. Thus, current evidence indicates that the rat D(3) gene is organized into eight exons. Transcription initiation site was determined by primer extension analysis and repeated rounds of 5' RACE and was found to localize at a pyrimidine-rich consensus 'initiator' sequence, similar to the rat D(2) gene. The D(3) promoter lacks TATA or CAAT boxes but unlike that of other dopamine receptor genes has only 52% GC content. Functional analysis of D(3) promoter deletion mutants fused to a reporter gene in TE671 cells, which endogenously express this gene, revealed strong transcriptional activity localized within 36 nucleotides upstream of transcription start site, and a potent silencer between bases --37 and --537. The D(3) promoter is inactive in C6 and COS7 cells. We conclude that the D(3) gene, similar to the closely related D(2) gene, is transcribed from a tissue specific promoter which is under intense negative control.

5' Untranslated Regions↗

PubMed2001

Possibility of sialographic sonography: a Doppler phantom study.

OBJECTIVES: The purpose of this study was to develop a new diagnostic method that has the merits of both sialography and sonography. STUDY DESIGN: Saline solution and various contrast media (Urografin 76%; 100%, 90%, and 67% Lipiodol Ultra-Fluide; 5% and 1% barium sulfate; and Levovist) were injected into thin tubes at a rate of approximately 0.001 to 0.1 mL/s. The relationship between the Doppler signal intensity and the kind, concentration, and velocity of the fluid was analyzed. RESULTS: Levovist, 90% and 67% Lipiodol Ultra-Fluide, and the barium sulfate solutions produced Doppler signals. The mixture of Lipiodol Ultra-Fluide and saline solution produced high signals at any concentration, in contrast with the barium sulfate solutions. Signals could be observed at any speed, from the speed of normal sialography down to 0.001 mL/s, and there was a proportional relationship between signal intensity and velocity for all fluids producing signals. CONCLUSION: The fact that we could obtain high signals with several fluids indicates potential clinical diagnostic usefulness of sialographic sonography.

Barium Sulfate↗

PubMed2001

The combined use of US and MR imaging for the diagnosis of masses in the parotid region.

PURPOSE: To evaluate the usefulness of the combination of the two non-invasive modalities US and MR imaging to diagnose masses in the parotid region. MATERIAL AND METHODS: The US and MR findings of 21 patients with parotid masses were analyzed retrospectively by two radiologists without any clinical or histopathological information. The specific points evaluated were location, shape, margin, internal architecture, and intensity level on both US and MR, posterior echo enhancement on US, and capsule-like lining of the tumor on MR. RESULTS: The findings concerning the shape and margin on US and MR were in fairly good agreement. Concerning the findings of the internal architecture, US could reveal the minute structures of the tumor while MR demonstrated differences in the signal intensities of histological tissue types of the various tumors. The posterior echo enhancement on US and the capsule-like lining on MR of the tumors were also useful for the diagnosis. CONCLUSION: Our results suggest that the combination of US and MR is useful for examining soft tissue masses in the parotid region to make a more accurate diagnosis, and not just differentiate malignant lesions from those which are benign.

Adolescent↗

PubMed2001

VEGF protects against oxidized LDL toxicity to endothelial cells by an intracellular glutathione-dependent mechanism through the KDR receptor.

Although the accumulation of vascular endothelial growth factor (VEGF) has been observed in human atherosclerotic lesions, the exact role of this growth factor in atherogenesis remains unknown. We hypothesized that VEGF in the vascular wall might have a preventive effect on endothelial cell damage during atherosclerosis. To test our hypothesis, we examined whether VEGF protects against the toxicity of oxidized low density lipoprotein (Ox-LDL) in cultured endothelial cells derived from bovine aortas (BAECs). Preincubation of BAECs with VEGF prevented Ox-LDL-induced toxicity in a preincubation time- and VEGF concentration-dependent manner. Addition of N(omega)-nitro-L-arginine methyl ester, a nitric oxide synthase inhibitor, did not reverse the protective effect of VEGF on Ox-LDL toxicity. Incubation of BAECs with VEGF increased intracellular glutathione (GSH) content in a time-dependent manner. Combined addition of VEGF and L-buthionine sulfoximine, a GSH synthesis inhibitor, reversed both GSH levels and the protective effect of VEGF on Ox-LDL-induced cytotoxicity. Placenta growth factor, which ligates to the VEGF Flt-1 receptor but not KDR/Flk-1, failed to prevent Ox-LDL toxicity and had no effect on intracellular GSH levels. An anti-KDR antibody completely blocked these beneficial activities of VEGF. These results suggest that VEGF prevents Ox-LDL-induced endothelial cell damage via an intracellular GSH-dependent mechanism through the KDR/Flk-1 receptor.

Animals↗

PubMed2001

Implantation of xenografts into the parkinsonian rat brain after portal venous administration of xenogeneic donor spleen cells.

OBJECT: The purpose of the present study was to examine the effect of pretransplantation portal venous immunization with ultraviolet B (UVB)-treated donor spleen cells on neural xenograft transplantation. METHODS: Cells from a murine catecholaminergic cell line derived from the B6/D2 F1 mouse, CATH.a, were used as a xenograft. Thirty hemiparkinsonian rats were divided into three different treatment groups. Group 1 received saline in the dopamine-denervated striatum; Group 2 received xenograft cells; and Group 3 received portal venous administration of UVB-irradiated B6/D2 F1 splenocytes 7 days before receiving xenograft cells. Xenograft function was determined by reviewing apomorphine-induced rotation at 2-week intervals, and xenograft survival was examined at 4 and 12 weeks after transplantation by immunohistochemical staining for murine tyrosine hydroxylase (THase). Rotational behavior was improved in both xenograft-transplanted groups (Groups 2 and 3); however, the animals in Group 3 displayed a significantly reduced rotational behavior compared with Group 2. In Group 2, many inflammatory cells and a few THase-positive cells were found at the graft sites 4 weeks after transplantation. In Group 3, however, a large number of THase-positive cells were found with few inflammatory cells. The THase-positive cells disappeared in the Group 2 rats at 12 weeks, but remained in Group 3 animals. In Group 3 rats proliferation of spleen cells in a mixed lymphocyte reaction was suppressed in a donor-specific fashion. CONCLUSIONS: This work demonstrates improved neural xenograft survival and function by pretransplantation portal venous immunization with UVB-irradiated xenogeneic donor splenocytes. On the basis of these findings, the authors suggest the possibility of creating donor-specific immunological tolerance in the brain by administration of xenogeneic donor lymphocytes via the portal vein.

Animals↗

PubMed2001

[Evaluation of bone metastases from renal cell carcinoma].

Forty-two cases of bone metastasis from renal cell carcinoma were examined. Thirty of the cases had bone metastases at the time of renal cell carcinoma. Bone metastasis appeared after treatment of the primary site in 12 cases. Fifteen cases had only bone metastasis and another 27 had metastasis in multiple organs. The total cause-specific survival curve of these patients was 10% at 5 years. All patients with bone metastases died of cancer within 5 years after the bone metastases had developed. There was no significant difference in the survival rate between patients with bone metastases and patients with lung metastases. We investigated the prognostic value of laboratory studies in bone metastases of renal cell carcinoma. However, no significant markers were detected for bone metastases. The 6 patients were treated with decompressed laminectomy (2), wide resection (3) and excision of the metastatic lesions (3). The quality of life was improved in all the patients although they died of cancer.

Adult↗

PubMed2000

Activation of MMP-2 by Clostridium difficile toxin B in bovine smooth muscle cells.

Matrix metalloproteinase-2 (MMP-2) plays critical roles in cell migration through the breakdown of the extracellular matrix. Cell movements require dynamic actin reorganization, which is controlled by Rho family GTPases. In order to examine the relation between MMP-2 regulation and actin reorganization, we used several inhibitors of Rho family GTPases. Treatment of smooth muscle cells with Clostridium difficile toxin B known to inactivate Rho family GTPases activated MMP-2. However, neither C3 transferase, a Rho inhibitor, nor Y-27632, a specific inhibitor of Rho-kinase, induced MMP-2 activation. Treatment with C3 transferase and Y-27632 caused morphological changes into the round and stellate shape, respectively, by inhibition of actin stress fiber formation. In addition, toxin B treatment induced expression and processing of MT1-MMP, a major activator of MMP-2. Taken together, we suggest the involvement of Rho family GTPases, although inhibition of neither Rho nor Rho-kinase is sufficient, in the activation of MMP-2 through expression and activation of MT1-MMP.

ADP Ribose Transferases↗

PubMed2000

Selectively desulfated heparin inhibits fibroblast growth factor-induced mitogenicity and angiogenesis.

Fibroblast growth factors (FGFs) are known to induce formation of new blood vessels, angiogenesis. We show that FGF-induced angiogenesis can be modulated using selectively desulfated heparin. Chinese hamster ovary cells (CHO677) deficient in heparan sulfate biosynthesis were employed to assess the function of heparin/heparan sulfate in FGF receptor-1 (FGFR-1) signal transduction and biological responses. In the presence of FGF-2, FGFR-1 kinase and subsequent mitogen-activated protein kinase Erk2 activities were augmented in a dose-dependent manner, whereas high concentrations of heparin resulted in decreased activity. The length of the heparin oligomer, minimally an 8/10-mer, was critical for the ability to enhance FGFR-1 kinase activity. The N- and 2-O-sulfate groups of heparin were essential for binding to FGF-2, whereas stimulation of FGFR-1 and Erk2 kinases by FGF-2 also required the presence of 6-O-sulfate groups. Sulfation at 2-O- and 6-O-positions was moreover a prerequisite for binding of heparin to a lysine-rich peptide corresponding to amino acids 160-177 in the extracellular domain of FGFR-1. Selectively 6-O-desulfated heparin, which binds to FGF-2 but fails to bind the receptor, decreased FGF-2-induced proliferation of CHO677 cells, presumably by displacing intact heparin. Furthermore, FGF-2-induced angiogenesis in chick embryos was inhibited by 6-O-desulfated heparin. Thus, formation of a ternary complex of FGF-2, heparin, and FGFR-1 appears critical for the activation of FGFR-1 kinase and downstream signal transduction. Preventing complex formation by modified heparin preparations may allow regulation of FGF-2 functions, such as induction of angiogenesis.

Allantois↗

PubMed2000

The nonreceptor protein-tyrosine kinase c-Fes is involved in fibroblast growth factor-2-induced chemotaxis of murine brain capillary endothelial cells.

Fibroblast growth factor-2 (FGF-2)-induced migration of endothelial cells is involved in angiogenesis in vivo. However, signal transduction pathways leading to FGF-2-induced chemotaxis of endothelial cells are largely unknown. Previous studies have shown that the cytoplasmic protein-tyrosine kinase c-Fes is expressed in vascular endothelial cells and may influence angiogenesis in vivo. To investigate the contribution of c-Fes to FGF-2 signaling, we expressed wild-type or kinase-inactive human c-Fes in the murine brain capillary endothelial cell line, IBE (Immortomouse brain endothelial cells). Wild-type c-Fes was tyrosine-phosphorylated upon FGF-2-stimulation in transfected cells, whereas kinase-inactive c-Fes was not. Overexpression of wild-type c-Fes promoted FGF-2-independent tube formation of IBE cells. Tube formation was not observed with endothelial cells expressing kinase-inactive c-Fes, indicating a requirement for c-Fes kinase activity in this biological response. Expression of kinase-defective c-Fes suppressed endothelial cell migration following FGF-2 treatment, suggesting that activation of endogenous c-Fes may be required for the chemotactic response. Expression of either wild-type c-Fes or the kinase-inactive mutant did not affect the tyrosine phosphorylation FRS2, Shc, or phospholipase C-gamma, nor did it influence the kinetics of mitogen-activated protein kinase activation. These results implicate c-Fes in FGF-2-induced chemotaxis of endothelial cells through signaling pathways not linked to mitogenesis.

Animals↗

PubMed2000

Enhanced vulnerability to oxidative stress by alpha-synuclein mutations and C-terminal truncation.

alpha-Synuclein is a key component of Lewy bodies found in the brains of patients with Parkinson's disease and two point mutations in this protein, Ala53Thr and Ala30Pro, are associated with rare familial forms of the disease. Several lines of evidence suggest the involvement of oxidative stress in the pathogenesis of nigral neuronal death in Parkinson's disease. In the present work we studied the effects of changes in the alpha-synuclein sequence on the susceptibility of cells to reactive oxygen species. Human dopaminergic neuroblastoma SH-SY5Y cells were stably transduced with various isoforms of alpha-synuclein and their survival following exposure to hydrogen peroxide or to the dopaminergic neurotoxin MPP(+) was assessed. Cells expressing the two point mutant isoforms of alpha-synuclein were significantly more vulnerable to oxidative stress, with the Ala53Thr engineered cells faring the worst. In addition, cells expressing C-terminally truncated alpha-synuclein, particularly the 1-120 residue protein, were more susceptible than control beta-galactosidase engineered cells. The present experiments indicate that point mutations and C-terminal truncation of alpha-synuclein exaggerate the susceptibility of dopaminergic cells to oxidative damage. Thus, these observations provide a pathogenetic link between alpha-synuclein aberrations and a putative cell death mechanism in Parkinson's disease.

1-Methyl-4-phenylpyridinium↗

PubMed2000

A new, simple method of making a spacer in interstitial brachytherapy for mobile tongue cancer.

OBJECTIVES: This article demonstrates a new method of making a spacer that increases the distance between the mandible and implanted radioactive sources in interstitial brachytherapy for patients with mobile tongue cancer. STUDY DESIGN: Fifty-three patients with mobile tongue cancer underwent interstitial brachytherapy with spacers made by this new technique. RESULTS: Our spacer is not difficult to create or to use. The spacer was made from a plastic splint by using thermoforming techniques and quick self-curing resin, which did not need waxing, wiring, or casting. The surface of the spacer, which comes in contact with the tongue, is smooth because it is covered with tissue-conditioning material. There were no complaints of pain from the patients. Osteoradionecrosis of the mandible developed in only 1 (1.9%) of these patients. CONCLUSIONS: This spacer is simple to make and prevented osteoradionecrosis.

Brachytherapy↗

PubMed2000

Sonographic analysis of rat submandibular glands in experimentally-induced sialadenitis.

OBJECTIVES: To correlate the sonographic features of experimentally-induced obstructive sialadenitis in rat submandibular glands with the histopathological changes. MATERIALS AND METHODS: Changes in sonograms of ligated and non-ligated rat submandibular glands were compared with the wet weight and histopathology. Sonograms were obtained at 1, 2, 3, 4, 5, 7 and 21 days after duct ligation at 13 and 14 MHz for B-mode and for power Doppler mode respectively. Changes in gland size, echo intensity, distribution of internal echoes and vascularity were evaluated both qualitatively and quantitatively. RESULTS: Changes in size of the ligated glands were very similar to changes in wet weight. The ligated glands showed lower echo intensity than the non-ligated glands. The ligated glands showed higher echo intensity in the central portion at 4-7 days after duct ligation which resulted in heterogeneity of the glands. Vascularity of the ligated glands increased in the acute phase, and then decreased to the level of the non-ligated glands. CONCLUSIONS: The three phases in the changes in ligated glands identifiable histopathologically can be differentiated by B-mode sonography. Power Doppler can differentiate the acute phase. Sonography therefore appears useful for the diagnosis of the degree of gland damage.

Acute Disease↗

PubMed2000

A study of the association between the prognosis of carcinoma of the mandibular gingiva and the pattern of bone destruction on computed tomography.

OBJECTIVE: To clarify whether the pattern of bone destruction seen on CT is more closely associated with the outcome of carcinoma of the mandibular gingiva than that derived from panoramic radiographs (PR). METHOD: Axial bone window CT scans and PR of 62 patients with carcinoma of the mandibular gingiva were evaluated retrospectively by two oral radiologists for the pattern of bone destruction. Patterns were classified into the three types: erosive, invasive and mixed. The relationship between these patterns with each imaging modality and cumulative recurrence rate, cumulative metastasis rate and cumulative survival rate, calculated by the Kaplan-Meier method, were statistically analysed by the log rank test. RESULTS: The pattern of bone destruction derived from CT was closely associated with the cumulative metastasis rate (P < 0.05), the cumulative recurrence rate and the cumulative survival rate. In contrast, the pattern of bone destruction based on the PR was not associated with the cumulative metastasis rate (P = 0.43), the cumulative recurrence rate (P = 0.44), or the cumulative survival rate (P = 0.5). CONCLUSION: The prognosis of patients with carcinoma of the mandibular gingiva is more closely related to a classification derived from the pattern of bone destruction on CT rather than PR. However, the number of subjects investigated in this study was not large enough to confirm our conclusions statistically. Further studies by other investigators are therefore needed.

Adult↗

PubMed2000

Computed tomography and ultrasonography of metastatic cervical lymph nodes in oral squamous cell carcinoma.

OBJECTIVES: To define criteria for CT and US in differentiating cervical lymph node metastases in oral squamous cell carcinoma (SCC). MATERIALS AND METHODS: CT and/or US of 230 metastatic lymph nodes and 228 benign lymph nodes in 147 patients with oral SCC were retrospectively evaluated. The CT and US findings of each lymph node were compared with the histopathological findings. A metastasis was defined on CT as a lymph node with rim or heterogeneous enhancement, or measuring 10 mm or more in the short axis, regardless of enhancement pattern, and on US as having definite internal echoes, regardless of size, or without definite internal or hilar echoes, but measuring 10 mm or more in the short axis. A lymph node with hilar echoes or a ratio of the long to short axis (L/S ratio) of 3.5 or more was considered benign. A lymph node failing to comform to any of these categories was termed questionable. RESULTS: The positive predictive value (PPV) for CT was 90.8% and the negative predictive value (NPV) was 70.4%. However, 65.7% of all lymph nodes could not be classified as either metastastic or benign. PPV for US was 96.5% and NPV was 88.1%. 25.5% of all lymph nodes could not be classified as either metastatic or benign. CONCLUSIONS: Despite limitations in detecting metastases, by including a third category 'questionable' our criteria appear clinically more useful than other current methods based on two groups only.

Adult↗

PubMed2000

Tumor recurrence criteria for postoperative contrast-enhanced computed tomography after surgical treatment of oral cancer and flap repair.

OBJECTIVE: To characterize the computed tomography (CT) findings that distinguish cancer recurrence from postoperative changes that mimic such recurrence. STUDY DESIGN: We evaluated a total of 72 CT scans from 32 patients who had undergone surgery with either pectoralis major myocutaneous flap or forearm flap. The observers evaluated the presence and pattern of enhancement, the presence of low density areas, and changes in the adipose tissue of the flap. RESULTS: A persistent zone of high attenuation over 6 months suggested the high possibility of recurrence. However, an enhancement within 6 months occurred both with the recurrent tumor and with postoperative tissue. In the patients with recurrence (n = 12), the enhanced areas were focal (n = 8) or diffuse (n = 4). Focal-type recurrence often occurred at the posterior margin. The presence of low-density areas and changes in the adipose tissue in the flap are also helpful for detecting recurrence. CONCLUSIONS: The combination of several features seen on CT images can be useful in differentiating tumor recurrence from postoperative tissue changes.

Adipose Tissue↗

PubMed2000

Matrix metalloproteinase and alphavbeta3 integrin-dependent vascular smooth muscle cell invasion through a type I collagen lattice.

Smooth muscle cell (SMC) migration from the tunica media to the intima is a key event in the development of atherosclerotic lesions and in restenosis after angioplasty. SMCs require not only migratory but also degradative abilities that enable them to migrate through extracellular matrix proteins, which surround and embed these cells. We used a collagen type I lattice as a coating on top of a porous filter as a matrix barrier in a chamber to test the invasive behavior of SMCs in response to a chemoattractant (invasion assay) and compared that behavior with simple SMC migration through collagen type I-coated filters (migration assay). Inhibitors of matrix metalloproteinase, KB-R8301, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1), TIMP-2, and peptide 74, attenuated platelet-derived growth factor-BB (PDGF-BB)-directed SMC invasion across the collagen lattice, whereas no effect was seen with these inhibitors on simple SMC migration through collagen-coated filters. RGD peptide inhibited SMC invasion but did not affect SMC migration. Anti-alphavbeta3 integrin antibody attenuated PDGF-BB-directed SMC invasion, whereas other antibodies against RGD-recognizing integrins, namely alphavbeta5 and alpha5, had no effect. None of these antibodies had any effect on simple SMC migration. RGD peptide and anti-alphavbeta3 antibody inhibited the attachment and spreading of SMCs on denatured collagen but not on native collagen. These findings indicate that there is a difference in the mechanisms between simple SMC migration across a collagen-coated filter and SMC invasion through a fibrillar collagen barrier. A proteolytic process is required for SMC invasion, and the degradation of matrix proteins alters the relationship between matrix protein molecules and SMC surface integrins.

Animals↗

PubMed2000

Role of conserved histidine residues in D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6.

D-Aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) was strongly inactivated by diethylpyrocarbonate (DEPC). An H67N mutant was barely active, with a kcat/Km 6.3 x 10(4) times lower than that of the recombinant wild-type enzyme, while the H67I mutant lost detectable activity. The H67N mutant had almost constant Km, but greatly decreased kcat. These results suggested that His67 is essential to the catalytic event. Both H69N and H69I mutants were overproduced in the insoluble fraction. The kcat/Km of H250N mutant was reduced by a factor of 2.5 x 10(4)-fold as compared with the wild-type enzyme. No significant difference between H251N mutant and wild-type enzymes in the Km and kcat was found. The Zn content of H250N mutant was nearly half of that of wild-type enzyme. These results suggest that the His250 residue might be essential to catalysis via Zn binding.

Alcaligenes↗