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S Kanda

Publications and source records attributed to S Kanda.

At least 19 recordsLinked to original sources
PubMed1997

Diltiazem derivatives modulate the dihydropyridine-binding to intact rat ventricular myocytes.

To examine whether the modulation of the 1,4-dihydropyridine-binding by diltiazem derivatives, which has been shown in cardiac and skeletal muscle membranes, takes place in intact cardiac myocytes, effects of diltiazem on the specific binding of [3H](+)-PN200-110 to freshly isolated adult rat ventricular myocytes were investigated in normal Tyrode solution at 37 degrees C. Diltiazem consistently potentiated the [3H](+)-PN200-110-binding in a concentration-dependent manner, while DTZ323 (3-(acetyloxy)-5-[2-[[2- (3,4-dimethoxyphenyl)ethyl]-methylamino]ethyl]-2,3-dihydro-2(-4 methoxyphenyl)-1,5-benzothiazepin-4-(5H)-one), a potent diltiazem derivative, inhibited it in a non-competitive manner. In saturation studies, 100 microM decreased the Kd value of the 3[H](+)-PN200-110-binding (control, 0.102 +/- 0.008 vs. diltiazem, 0.074 +/- 0.004 (nM, n = 6), P < 0.05) without significant effect on Bmax (control, 65.7 +/- 6.4 vs. diltiazem, 76.7 +/- 4.4 (fmol/mg protein, n = 6). Moreover, membrane-impermeant quaternary diltiazem also potentiated the [3H](+)-PN200-110-binding in intact myocytes. These results suggest that diltiazem modulates the 1,4-dihydro-pyridine-binding even in intact cardiac myocytes, and the binding site of diltiazem is accessible from the extracellular side of the L-type Ca2+ channels.

Animals↗
PubMed1997

Idiopathic osteosclerosis of the jaws: panoramic radiographic and computed tomographic findings.

OBJECTIVE: The purpose of this study was to determine the frequency and anatomic location of idiopathic osteosclerosis in the jawbones and to present computed tomographic findings of this lesion in Japanese patients. STUDY DESIGN: Panoramic radiographs of 1047 patients were examined for the presence of idiopathic osteosclerosis in the jawbones. Computed tomography was performed in 11 patients of this series. RESULTS: A total of 64 patients (6.1%) showed this radiopacity. The highest occurrence was in the mandibular first molar region. There was no statistically significant difference in the prevalence of idiopathic osteosclerosis between males and females. On computed tomography images, these radiopaque areas were divisible into two types: enostosis (five cases) and central sclerosis (six cases). CONCLUSION: This is the first report of computed tomographic findings on idiopathic osteosclerosis in the jawbones, although the results on panoramic radiographs are similar to other investigators.

Adolescent↗
PubMed1997

Reliability of ultrasonography and sialography in the diagnosis of Sjögren's syndrome.

OBJECTIVE: The purpose of this study was to evaluate quantitatively observer performance with ultrasonography and sialography in the diagnosis of parotid gland involvement of Sjögren's syndrome. STUDY DESIGN: Sixty-four parotid gland sialograms and 65 ultrasonograms were prepared for observer performance experiments. They included both modalities in 24 Sjögren's syndrome and 19 nonspecific parotitis cases, 21 normal parotid gland sialograms, and 22 normal ultrasonograms in healthy volunteers. The images were randomly sequenced and presented to five observers who were asked to describe several findings and finally to determine the imaging diagnosis by ranking the abnormal features and the diagnosis on a five-point-rating scale. Observer performance was evaluated on the basis of the reliability of findings interpreted and the diagnostic accuracy of each modality from observers' rating scores. RESULTS: The diagnostic accuracy of sialography was very high, nearly perfect. The diagnostic accuracy of ultrasonography was lower than that of sialography, resulting from the lower incidence of characteristic findings in the disease groups and lower sensitivity on ultrasonography. In the differentiation of Sjögren's syndrome from the normal, however, the diagnostic accuracy of ultrasonography increased to 80% for all cases, and up to nearly 90% in the advanced sialographic stages. CONCLUSION: Ultrasonography is useful for the diagnosis of Sjögren's syndrome in the advanced stages. Taking the noninvasiveness of this technique into account we recommend first applying ultrasonography to the diagnosis of Sjögren's syndrome and performing sialography when no positive findings are detected on ultrasonography.

Analysis of Variance↗
PubMed1996

Basic fibroblast growth factor stimulates phosphatidylcholine-hydrolyzing phospholipase D in osteoblast-like cells.

We examined the effect of basic fibroblast growth factor (bFGF) on the activation of phosphatidylcholine-hydrolyzing phospholipase D in osteoblast-like MC3T3-E1 cells. bFGF stimulated both the formations of choline (EC50 was 30 ng/ml) and inositol phosphates (EC50 was 10 ng/ml). Calphostin C, an inhibitor of protein kinase C (PKC), had little effect on the bFGF-induced formation of choline. bFGF stimulated the formation of choline also in PKC down regulated cells. Genistein and methyl 2,5-dihydroxycinnamate, inhibitors of protein tyrosine kinases, significantly suppressed the bFGF-induced formation of choline. Sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, enhanced the bFGF-induced formation of choline. In vitro kinase assay for FGF receptors revealed that FGF receptor 1 and 2 were autophosphorylated after FGF stimulation. bFGF dose-dependently stimulated DNA synthesis of these cells. These results strongly suggest that bFGF activates phosphatidylcholine-hydrolyzing phospholipase D through the activation of tyrosine kinase, but independently of PKC activated by phosphoinositide hydrolysis in osteoblast-like cells.

Animals↗
PubMed1996

Induction of fibroblast growth factor receptor-1 mRNA and protein by platelet-derived growth factor BB.

Expression levels of growth factor receptors are subject to complex regulation, which is of consequence for their signaling capacity in physiological and pathological processes. We examined the regulation of expression levels of fibroblast growth factor receptor 1 (FGFR-1) in human fibroblasts treated with a panel of growth regulatory factors. Only platelet-derived growth factor BB (PDGF-BB) treatment had a significant effect and induced FGFR-1 mRNA levels fourfold, with a peak around 8 h of stimulation. The increase in mRNA levels was followed by an increased synthesis of FGFR-1 protein, which responded to basic FGF (bFGF) stimulation with induction of kinase activity and biological signaling. Thus, murine brain endothelial cells displayed an augmented induction of plasminogen activator activity in response to bFGF, following treatment with PDGF-BB. These data suggest that PDGF-BB could support FGFR-1-mediated biological responses in processes such as angiogenesis.

Animals↗
PubMed1996

Expression of manganese superoxide dismutase mRNA in reproductive organs during the ovulatory process and the estrous cycle of the rat.

Expression of manganese superoxide dismutase (Mn-SOD) mRNA during the pregnant mare serum gonadotrophin (PMSG)/human chorionic gonadotrophin (HCG)-induced ovulatory process, and during the estrous cycle was examined in rat female reproductive organs. Mn-SOD mRNA levels in theca interna cells markedly increased in PMSG-primed rats and high levels of the transcripts were maintained after HCG injection. The PMSG-enhanced expression of Mn-SOD mRNA in follicular epithelial cells increased concomitantly with luteinization of these cells. The levels of Mn-SOD mRNA remained high and became equivalent in both granulosa and theca lutein cells 24 h after HCG injection. Neither luteinization nor the expression of Mn-SOD mRNA was observed in the epithelial cells of unovulated follicles. Luteal bodies had formed 3 days after HCG injection, and the same level of Mn-SOD mRNA expression continued in lutein cells, but not in stromal cells. During the estrous cycle, Mn-SOD mRNA was localized to theca interna cells on proestrus, to the epithelial cells of luteinizing follicles on estrus, and to newly formed luteal bodies on diestrus. The epithelial cells in the oviduct did not express Mn-SOD mRNA throughout the ovulatory process or the estrous cycle. Expression of Mn-SOD mRNA in the luminal epithelial cells of the uterus increased after PMSG injection, reaching a maximum after 24 h, and became relatively negative 3 days after HCG injection when corpora lutea had formed in the ovary. During the estrous cycle, uterine epithelial cells and leukocytes showed marked increases in Mn-SOD mRNA expression on estrus and on proestrus, respectively. Expression in the vaginal epithelium became apparent 3 days after HCG injection and continued for at least 12 days after HCG injection. The expression was localized to the superficial layer of the epithelium. During the estrous cycle, expression occurs in the basal layer on proestrus and estrus, transferring to the superficial layer on diestrus day 1, and expression stops on diestrus day 2. The relationship between the expression of Mn-SOD mRNA and hormone-induced metabolic changes, including steroidogenesis, is discussed.

Animals↗
PubMed1996

Diagnostic value of magnetic resonance imaging for malignant tumors in the oral and maxillofacial region.

The purpose of this study was to clarify the diagnostic value of magnetic resonance imaging for malignant tumors in the oral and maxillofacial region. Computed tomography and magnetic resonance images of 25 patients with malignant tumors of the oral and maxillofacial region were evaluated. Computed tomography scans were performed with intravenous contrast enhancement. A 0.2-Tesla (Hitachi Medical Corp., Tokyo, Japan) permanent magnetic resonance unit was used to obtain T1-, T2-, and proton-density-weighted images with spin-echo pulse sequences. Gadolinium-diethylene-triamine-pentaacetic acid was administered in 11 cases. Severe artifacts influencing image interpretation were observed in 10 (40%) cases on computed tomography but only in 5 (20%) cases on magnetic resonance imaging. There was no difference in the detectability of bone invasion between images from the two systems. Contrast enhancement with gadolinium-diethylene-triamine-pentaacetic acid provided additional useful information in only 3 of 11 cases compared with nonenhanced magnetic resonance images. Malignant tumors showed a higher signal intensity than that of muscle on T2-weighted images in all cases and on proton-density-weighted images in 23 (92%) cases. On T1-weighted images, an intermediate signal intensity similar to that of muscle was seen in 16 (64%) cases and a hyperintense signal in 9 (36%) cases. There was poor correlation between signal intensity and pathologic diagnosis of the tumors. These results suggest that in cases with severe artifacts that disturb the interpretation of the images on computed tomography, magnetic resonance examinations are preferable for defining the exact extent of the primary lesion.

Adult↗
PubMed1996

Human simple renal cyst fluid contains a cyst formation-promoting activity for Madin-Darby canine kidney cells cultured in collagen gel.

Simple renal cysts are commonly observed in the elderly, but few examinations have been performed to study the mechanism of this disease. We have previously shown that simple renal cyst fluid contains some growth factors, including epidermal growth factor (EGF; less than 54 pg mL-1) and insulin-like growth factor I (IGF-I; 30-2070 pg mL-1) (M. Taide et al. Clin Chim Acta, 1993; 217:199-203). In this report, the biological significance of growth factors or of human simple renal cyst fluid on the formation of renal epithelial cyst was determined using Madin-Darby canine kidney (MDCK) cells cultured in collagen gel. Both EGF (200 pg mL-1 or more) and IGF-I (100 pg mL-1 or more) were found to stimulate cyst formation in MDCK cells. Additionally, 12/21 human simple renal cyst fluid samples were found to be capable of stimulating cyst formation in MDCK cells. This activity was due to a heat- and acid-labile protein and not inhibited by the anti-IGF-I neutralizing antibody. These results indicate that in some instances simple renal cyst fluid would thus appear to contain specific activity for cyst formation, which may affect cyst formation in vivo.

Animals↗
PubMed1996

Computed tomographic indices for maxillary sinus size in comparison with the sinus volume.

OBJECTIVES: To ascertain the normal range of maxillary sinus size and its changes with age on computed tomography (CT) and define convenient indices for sinus size, in addition, to examine the association of the height of the sinus floor with age and status of the dentition. METHODS: The transverse and anteroposterior dimensions of the normal maxillary sinuses in 107 subjects were measured on axial CT and the relationship between these values and the sinus volume analysed. The height of the sinus floor was obtained by measuring the vertical distance from the anterior nasal spine to the sinus floor. RESULTS: The mean transverse and anteroposterior widths of the normal adult maxillary sinuses were 2.70 (s.d., 0.60) cm and 3.56 (s.d., 0.47) cm, respectively. There was a close correlation with sinus volume which could be predicted well from the multiple regression formula. These values increased up to the age of 20 y, but then decreased. There was no significant difference between subjects aged 50-79 years with and without maxillary premolars and molars. The width of the adult sinus correlated with the interzygomatic buttress distance and body weight. The mean height of the adult maxillary sinus floor was 0.37 (s.d., 0.44) cm inferior to the anterior nasal spine. It correlated negatively with sinus volume and fell with age up to 20 y, then rose again. In adults, it was not significantly influenced by the dentition status, and rose in proportion to the decrease in the interzygomatic buttress distance, and body height and weight. CONCLUSION: The transverse and anteroposterior widths of the maxillary sinus on axial CT are convenient indices for its size. The height of the sinus floor altered with changes in sinus volume, but was not directly influenced by the status of the dentition.

Adolescent↗
PubMed1996

Fibroblast growth factor receptor 1-induced differentiation of endothelial cell line established from tsA58 large T transgenic mice.

Angiogenesis of capillary endothelial cells includes at least four sequential cellular responses: digestion of basement membrane, migration, proliferation, and differentiation. To study differentiation of endothelial cells, we established a brain capillary endothelial cell line from H-2Kb-tsA58 transgenic mice. These cells are stable at 33 degrees C and display endothelial cell-specific characters, such as expression of von Willebrand factor and binding sites for the lectin Bandeiraea simplifolia, and uptake of acetylated-low density lipoprotein. We measured the effects of a panel of growth factors on cellular responses. A number of factors, such as hepatocyte growth factor, vascular endothelial growth factor, and platelet-derived growth factor (PDGF)-AA failed to induce biological responses. PDGF-BB, epidermal growth factor, and acidic and basic fibroblast growth factor (FGF) induced proliferation of the cells. Of all the factors tested, only acidic FGF and basic FGF induced differentiation of the cells, visualized as the formation of tube-like structures of cells grown in three-dimensional collagen gels. All factors were also analyzed for their effects on plasminogen activator (PA)-induction and migration of the cells. Transfected cells, expressing a chimeric receptor, composed of the extracellular part from the PDGF alpha-receptor and the intracellular part from FGF receptor-1, responded to PDGF-AA treatment with plasminogen activator induction, migration, proliferation, and tube formation in collagen. These results indicate that FGF receptor-1 coupled to signal transduction pathways, leading to differentiation. This novel cell model offers the potential of detailed dissection of signal transduction pathways involved in the differentiation of endothelial cells.

Animals↗
PubMed1995

Shc and a novel 89-kDa component couple to the Grb2-Sos complex in fibroblast growth factor-2-stimulated cells.

A major pathway for mitogenicity is gated via the small GTP-binding protein Ras. Receptor tyrosine kinases couple to Ras through the Src homology 2 (SH2) domain protein Grb2. The activated fibroblast growth factor receptor-1 (FGFR-1) expressed in L6 myoblasts did not bind Grb2 directly, but indirectly, through the small adaptor protein Shc, which was tyrosine-phosphorylated in response to fibroblast growth factor-2 (FGF-2) stimulation. A FGFR-1 mutant in which Tyr766, a known autophosphorylation site, was changed to Phe, mediated less efficient tyrosine phosphorylation of Shc. FGF-2 stimulation of mutant FGFR-1-expressing cells still allowed formation of complexes containing Shc, Grb2, and the nucleotide exchange factor Sos and mediation of a mitogenic signal. Another pool of Grb2 was found in complex with a tyrosine-phosphorylated 89-kDa component after FGF-2 stimulation. Stimulation with other growth factors did not lead to tyrosine phosphorylation of p89. As shown by "far-Western" analysis, p89 bound directly to the Grb2 SH2 domain, and this interaction was inhibited by a peptide containing the Y(P)-X-N motif. Tyrosine-phosphorylated p89 was found exclusively in the membrane fraction, indicating its role in bringing Grb2, as well as Sos, to the plasma membrane. These data support the concept of growth factor-specific coupling of Grb2 to the Ras pathway.

Adaptor Proteins, Signal Transducing↗
PubMed1995

[Hypertrophy and hyperplasia of renal tubular interstitial cells--regulatory factors].

Renal tubular cells do not proliferate under normal intact conditions, whereas a marked regeneration is evident when tubular cells are injured by renal toxins or by ischemia. In case of compensatory renal growth too, hyperplasia of renal proximal tubular cells is observed. Various growth factors, including epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) seem to be involved in renal regeneration, however, the physiological role of these growth factors for the natural course of the renal regeneration have yet to be established. Hepatocyte growth factor (HGF), a potent mitogen for cultured renal tubular cells, may function as a renotropic factor, which enhances regeneration of the kidney. Once renal tubular cells are damaged by some agents, HGF mRNA, HGF activity and DNA synthesis of renal tubular cells are sequentially increased. Since both HGF mRMA and HGF protein are localized in renal interstitial cells, HGF seems to act on the tubular cells as a paracrine mediator. In addition to these results, HGF has multiple biological functions. This suggests that HGF possesses biological activities essential for renal regeneration.

Animals↗
PubMed1994

Imaging features of maxillary osteoblastoma and its malignant transformation.

We report two cases of osteoblastoma, one of them an unusual case in a 32-year-old woman in whom a maxillary tumor was confidently diagnosed as an osteoblastoma at the time of primary excision and subsequently transformed into an osteosarcoma 7 years after the onset of clinical symptoms. The other patient developed osteosarcoma arising in the maxilla, which was diagnosed 3 years after the primary excision and is very suggestive of malignant transformation in osteoblastoma. We present the radiological features, including computed tomographic and magnetic resonance imaging studies, of this unusual event of transformed tumor and compare imaging features of benign and dedifferentiated counterparts of this rare tumor complex.

Adult↗
PubMed1994

Detection of manganese superoxide dismutase mRNA in the theca interna cells of rat ovary during the ovulatory process by in situ hybridization.

To determine the possible involvement of reactive oxygen species in ovulation, dynamic aspects of superoxide dismutase (SOD) isozyme were studied in the ovaries of rats by in situ hybridization histochemistry. Previously, mRNA levels of ovarian manganese superoxide dismutase (Mn-SOD) were reported markedly to increase whilst enzymic activity of Mn-SOD decreased during the ovulatory process after treating immature rats with 10 and 5 Units, respectively, of pregnant mare serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG). Levels of Cu/Zn-SOD activity and Cu/Zn-SOD mRNA were reported to remain unchanged throughout ovulation. This increase in the Mn-SOD mRNA level was shown in the present study by in situ hybridization to be localized to the theca interna cells throughout the PMSG/HCG-induced ovulatory process. The observations suggest that the turnover rate of Mn-SOD but not Cu/Zn-SOD increases specifically in the mitochondria of these cells. SOD has been postulated to play important roles in steroidogenesis. The relationship is discussed between mitochondrial functions in steroid-secreting cells and superoxide radicals and related metabolite(s).

Animals↗
PubMed1994

Both VH and VL regions contribute to the antigenicity of anti-idiotypic antibody that mimics melanoma associated ganglioside GM3.

Previously we developed a murine monoclonal anti-idiotype (anti-id) antibody (4C10) that mimics the melanoma-associated ganglioside antigen GM3, that is, it carries the internal image of GM3. 4C10 was made against the human monoclonal antibody (HuMAb) L612, which reacts with several types of human cancer cells, including melanoma and breast cancer. To reduce mouse components of 4C10, the constant region was replaced by a human constant domain to form the murine/human chimeric anti-id antibody TVE-1. In the present study, we sought to determine which chain (VH or VL) of the anti-id is responsible for the antigenicity of GM3. The TVE-1 VH and VL expression vectors were simultaneously transfected with either the VH or VL expression vector of a murine-human chimeric IgG antidansyl haptenic antibody, resulting in the construction of three different combinations of VH and VL chimeric antibodies. These IgG molecules were produced from the transfectomas, and their reactivity to HuMAb L612 was tested. Neither of the IgG proteins that had cross-combined the VH-VL pair showed positive results, suggesting that both heavy and light chains are required to express the antigenicity. The in vivo antigenicity of this chimeric anti-id was confirmed by skin tests in melanoma patients receiving active specific immunotherapy.

Animals↗
PubMed1994

Florid cemento-osseous dysplasia. Radiographic study with special emphasis on computed tomography.

This article describes the computed tomographic and conventional radiographic findings for florid cemento-osseous dysplasia. A low-density thin layer or cystlike area was observed around the high-density masses in the tooth-bearing area in the seven cases studied. Expansion of the buccal and lingual cortical plates was observed in association with cystlike areas, but was infrequently observed in florid cemento-osseous dysplasia not having such areas. The computed tomographic number of the high-density masses ranged from 772 to 1587 Hounsfield Units and was equivalent to that of cementum or cortical bone.

Adult↗
PubMed1994

Ultrasonographic evaluation of inflammatory changes in the masseter muscle.

The ultrasonographic images of 32 patients with inflammatory change in the masseteric region were investigated to clarify the characteristic findings and to evaluate the utility of ultrasonography. Inflamed masseter muscles frequently demonstrated reduction of echo intensity and complete or partial absence of hyperechoic bands. The mean thickness of the masseter muscle on the unaffected side was 8.6 mm, whereas that on the affected side was 12.9 mm. Nine of 10 patients with heterogeneous hypoechoic area, but only 1 of 10 patients with homogeneous hypoechoic area, had received surgical treatment before ultrasonographic examination.

Abscess↗