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S Toda

Publications and source records attributed to S Toda.

At least 19 recordsLinked to original sources
PubMed2005

Quantification of oxidative metabolism in masseter muscle of denture wearers.

This study aimed to quantify oxidative metabolism in masseter muscle using near-infrared spectroscopy, in particular for denture wearers. Fourteen normal dentate subjects without malocclusion (ND group, 25-50 years) participated in the quantification of oxidative metabolism. Eleven partially edentulous patients without occlusal stops (PD group, 64-80 years) and ten edentulous patients (CD group, 57-84 years) also participated after prosthodontic treatment. Oxidative metabolism was recorded during gum chewing, maximum clenching and regulated clenching at 5 kgf. The oxygenated hemoglobin at 5 kgf clenching level was normalized to the oxygenated hemoglobin at the lowest blood flow and expressed as oxygen consumption rate (OCR). The relationship of the OCR to the maximum clenching force was analyzed using Pearson's correlation coefficient, and differences between the PD and CD groups were tested by unpaired Student's t-test. The OCR showed a significant negative correlation with maximum clenching force in the ND group. The OCR of the PD group was significantly greater than that of the CD group, although the difference in maximum clenching force was not significant between both groups. These results suggest that the aerobic ability of masseter muscle in complete denture wearers is relatively greater than in partial denture wearers with same age level.

Aged↗
PubMed2004

Which infertile women should be indicated for sonohysterography?

OBJECTIVE: To evaluate the indications for transvaginal saline contrast sonohysterography (TV-SCSH) in endometrial screening by transvaginal sonography in infertile women. METHODS: The study involved 850 consecutive infertile women presenting to an outpatient clinic. Using transvaginal ultrasound endometrial images were evaluated in the proliferative phase. Abnormal images were classified as follows: rugged (R), hyperechoic (H), waved (W), or thick (T). Clinical symptoms such as hypermenorrhea, dysmenorrhea and abnormal uterine bleeding were also recorded. Abnormal endometrial images were further evaluated on TV-SCSH. Age-matched women with normal endometrial images underwent TV-SCSH as controls. RESULTS: The endometrial pattern was abnormal in 111 patients (13.1%). Lesions that had been identified by TV-SCSH including endometrial polyps (44 cases), submucosal myomata (29 cases), and intramural myomata with mucosal extension (24 cases) were largely associated with the R and/or the H pattern, the W or the T pattern, and the W pattern, respectively. Sensitivity and specificity of the abnormal endometrial image for any lesion were 100% and 91.5%, respectively. Sixty-four patients (59.3%) were asymptomatic despite an abnormal endometrial image. CONCLUSIONS: TV-SCSH should be performed on selected patients following assessment of endometrial images on transvaginal sonography in order to diagnose intra- and pericavitary lesions in infertile women.

Adult↗
PubMed2004

Two amino acid substitutions in acetylcholinesterase associated with pirimicarb and organophosphorous insecticide resistance in the cotton aphid, Aphis gossypii Glover (Homoptera: Aphididae).

The complete coding sequences of two acetylcholinesterase (AChE) genes, Ace1 (orthologous to Drosophila Ace) and Ace2 (paralogous to Ace), from the cotton aphid (Aphis gossypii) were identified and sequences from carbamate resistant and susceptible strains compared. No change in the amino acid sequences was found in Ace1, while two amino acid substitutions, Ser431Phe and Ala302Ser, were detected between resistant and susceptible strains in Ace2. The position of Ser431Phe corresponds to one of fourteen aromatic residues lining the active site gorge and is located in the acyl pocket. Ala302Ser is located at one of the three residues which form the oxyanion hole in the active site of AChE. The Ser431Phe and Ala302Ser substitutions may play a role in pirimicarb and organophosphate resistance, respectively.

Acetylcholinesterase↗
PubMed2003

Prostate cancer cell growth is modulated by adipocyte-cancer cell interaction.

OBJECTIVE: To assess whether adipocytes (mesenchymal stromal cells thought to affect the proliferation and differentiation of epithelial cells) affect the behaviour of prostate cancer cells in vitro, as prostate cancer metastasizes to the bone, which is an adipocyte-rich environment. MATERIALS AND METHODS: The human bone-metastatic prostate carcinoma cell line PC3 was cultured with or without adipocytes in a three-dimensional collagen gel matrix. Histological and immunohistochemical assays were used to evaluate the proliferation and differentiation of PC3 cells. The cytokine expression of this culture assembly was also examined by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: The proliferation and differentiation of cancer cells were clearly changed on co-culture with adipocytes compared with the control cultures. The mean (range) bromodeoxyuridine (BrdU) indices estimated (according to uptake) to evaluate the growth of the cultured cells were 36.3 (8.55)% in the co-culture and 26.95 (10.50) in the control (P < 0.02). PC3 cells in co-culture formed larger clusters than in the control, at 16.0 (11.0) vs 14.0 (10.0), respectively (P < 0.01). Cancer cells also showed pleomorphism, varying from cuboidal to spindle-shaped. The expressions of vascular endothelial and platelet-derived growth factor were greater in co-culture than in the control. CONCLUSION: These findings suggest that adipocytes modulate the growth, morphology and cytokine expression of prostate cancer cells. This specific mesenchymal stromal cell type is important in the biological behaviour of prostate cancer cells.

Adipocytes↗
PubMed2003

Mexiletine carbonyloxy beta-D-glucuronide: a novel metabolite in human urine.

1. The study was performed to isolate and characterize a glucuronic acid conjugate of mexiletine that releases mexiletine on acid hydrolysis from urine samples obtained from healthy volunteers following a single oral dose of mexiletine. 2. The [M-H]- ion of the isolated metabolite was observed at m/z 398 in the negative electrospray ionization mass spectrum. This mass number was 44 higher than that of the product generated when mexiletine is subjected to direct glucuronidation. In positive-ion mode, collision-induced dissociation of the quasimolecular ion [M+NH4]+, m/z 417, gave product ions at m/z 224, 180 and 58. These mass spectral data indicated that the metabolite contained a carbonyloxy moiety in its structure in addition to mexiletine and a glucuronic acid moiety. 3. The presence of this carbonyloxy moiety was further supported by the following chemical reactions. When the metabolite was hydrolysed with an aqueous solution of 1 M sodium hydroxide at room temperature, mexiletine was released, whereas the N-methoxycarbonyl derivative of mexiletine was obtained after treatment of the metabolite with methanolic sodium hydroxide solution. 4. The results indicated that the structure of the isolated metabolite was the N-carbonyloxy beta-D-glucuronic acid conjugate of mexiletine.

Adult↗
PubMed2002

Highly reproducible rat model of reversible forebrain ischemia--modified four-vessel occlusion model and its metabolic feature.

BACKGROUND: The four-vessel occlusion method introduced by Pulsinelli et al. is widely used as an experimental model for reversible forebrain ischemia in rats. METHOD: In this study, we further developed highly reproducible model of reversible forebrain ischemia. Under the microscope the visible vertebral arteries at the second vertebra could be easily electrocauterized and completely cut to yield complete cessation of circulation of both vertebral arteries. After 24 hours, male Wistar rats were subjected to 15, 30 and 45 minutes of forebrain ischemia by occluding both common carotid arteries with Sugita's temporary clips. (31)P-magnetic resonance spectra ((31)P-MRS) and (1)H-magnetic resonance images ((1)H-MRI) were obtained with a 6.3-T spectrometer to investigate sequential change of the in vivo brain metabolism. Electroencephalogram and the cortical blood flow by laser Doppler flowmetry were measured during ischemia and recirculation. Determination of endogenous superoxide scavenging activity in the brain cortex was performed by electron spin resonance spectrometry. FINDINGS: Brain water contents evaluated by the dry-wet weight method were increased at 1 hour and 48 hours after recirculation, which were demonstrated by (1)H-MRI. The superoxide scavenging activity showed a significant decrease at 45 minutes of recirculation and a significant increase at 12 hours of recirculation. The present modified model demonstrated that the mortality rates by 72 hours were 8.3% (15 minutes ischemia), 15.0% (30 minutes ischemia), and 42.9% (45 minutes ischemia), all of which were higher than that of the original method described by Pulsinelli et al. INTERPRETATION: In conclusion, this modified four-vessel occlusion method gives a high level of success in producing reversible forebrain ischemia.

Animals↗
PubMed2001

Constitutive activation of Wnt/beta-catenin signaling pathway in migration-active melanoma cells: role of LEF-1 in melanoma with increased metastatic potential.

A constitutive complex of beta-catenin and LEF-1 has been detected in melanoma cell lines expressing either mutant beta-catenin or mutant APC (Rubinfeld et al., Science, 275, 1790-1792, 1997). However, it has been recently reported that beta-catenin mutations are rare in primary malignant melanoma, but its nuclear and/or cytoplasmic localization, a potential indicator of Wnt/beta-catenin pathway activation, is frequently observed in melanoma (Rimm et al., Am. J. Pathol., 154, 325-329, 1999). In human malignant melanoma, the appearance of the tumorigenic phase represents a capacity for metastasis and is the significant phenotypic step in disease progression. Cell motility in invasive melanoma is thought to play a crucial role in metastatic behavior. In this work, we sought to determine which transcription factor of the LEF/TCF family was preferentially involved in human melanoma from different stages of tumor progression. We show that LEF-1 mRNA expression is predominant in highly migrating cells from metastatic melanomas. These actively migrating melanoma cells showed nuclear and cytoplasmic accumulation of beta-catenin and active transcription from a reporter plasmid of the LEF/TCF binding site. These results may provide a new insight into the role of the Wnt/beta-catenin signaling pathway in the tumor progression of malignant melanoma.

Cell Movement↗
PubMed2001

Inhibitory effects of aromatic herbs on lipid peroxidation and protein oxidative modification of mice brain homogenate by copper in vitro.

Several aromatic herbs were inferred to have inhibitory effects on the generation of oxygen free radicals. It has been demonstrated that free radicals produced by copper produce lipid peroxidation and protein oxidative modification in the brain. The results presented here showed that several aromatic herbs, Caryophylli flos, Cinnamomi cortex, Foeniculi fructus and Zedoariae rhizoma, have inhibitory effects on lipid peroxidation or protein oxidative modification of mice brain homogenate produced by copper in vitro.

Animals↗
PubMed2001

Subcutaneous adipocytes promote the differentiation of squamous cell carcinoma cell line (DJM-1) in collagen gel matrix culture.

Cancer cell-stromal cell interaction plays a crucial role in the malignant growth of cancer cells. In the skin, the main stromal cell types consist of dermal fibroblasts and subcutaneous adipocytes. Fibroblasts are shown to promote the invasive growth of various cancer cell types. The interaction between cancer cells and stromal adipocytes, however, has not been sufficiently studied even in cutaneous carcinoma. To address the effects of adipocytes on the biologic behavior of cancer cells, we examined the growth and differentiation of a squamous cell carcinoma cell line of the skin (DJM-1), using a three-dimensional collagen gel matrix culture with a cutaneous environmental factor, air exposure. The growth was estimated by the uptake of bromodeoxy-uridine (BrdU) for 24 h. The BrdU indices of DJM-1 cells in stromal-cell-free, fibroblast-containing, and adipocyte- containing conditions were 19.7 +/- 1.9%, 19.8 +/- 2.8%, and 4.7 +/- 1.4%, respectively, whereas the BrdU index on the gel containing both fibroblasts and adipocytes was 10.4 +/- 3.3%. In terms of differentiation, DJM-1 cells cocultured with adipocytes constructed the best-organized stratified layer with a cornified-like structure in all conditions above. The differentiation markers involucrin and cytokeratin 10 were immunohistochemically detected in this structure of DJM-1 cells. Adipocyte-induced phenomena were not affected distinctively by air exposure. These results indicate that adipocytes, but not fibroblasts, promote the differentiation of squamous cell carcinoma cells (DJM-1) and inhibit their growth. These adipocyte-induced phenomena were not completely inhibited by fibroblasts. In conclusion, we suggest that stromal adipocytes may be involved in the differentiating mechanisms of cutaneous carcinoma cells.

Adipocytes↗
PubMed2001

Effects of fat cells on keratinocytes and fibroblasts in a reconstructed rat skin model using collagen gel matrix culture.

BACKGROUND: Fat cells (stromal tissue cells), not only have the function of lipid metabolism, but produce various cytokines that exert an influence on other cell types through paracrine or endocrine mechanisms. OBJECTIVES: To elucidate possible roles of fat cells in the skin, we examined their effects on the biological behaviour of keratinocytes and dermal fibroblasts in culture. METHODS: In the present study, focusing upon fat cell--keratinocyte or fat cell--dermal fibroblast interactions, we used a reconstructed skin system with rat skin cells in a three-dimensional collagen gel matrix culture. RESULTS: In this coculture system, fat cells promoted the proliferation and differentiation of keratinocytes. When keratinocytes were seeded directly on the fat cell layer without dermal fibroblasts, they proliferated extensively and formed a thick epidermal layer with a well-differentiated structure. Conversely, fat cells inhibited the proliferation of dermal fibroblasts. These effects of fat cells were presumed to be mediated by cytokines derived from the fat cells. CONCLUSIONS: The effects of fat cells could not be mimicked by the addition of leptin, tumour necrosis factor-alpha or insulin-like growth factor-II, suggesting that fat cells are mediating these activities via some other cytokines.

Adipocytes↗
PubMed2001

Activation of HIV-1-specific immune responses to an HIV-1 vaccine constructed from a replication-defective adenovirus vector using various combinations of immunization protocols.

We constructed a recombinant replication defective adenovirus vector containing the env gene (Ad-Bal) derived from macrophage-trophic HIV-1 (HIV-1 Bal). We then immunized mice with this vector using several administration routes and protocols, and examined the immune response. When the Ad-Bal viral vector (over 1 x 10(7) pfu) was injected subcutaneously, both humoral and cell-mediated immunities were induced. However, immune response induced by the Ad-Bal vector alone was weaker than that induced by the recombinant vaccinia viral vector. We then employed the following three immunization protocols: (l) DNA vaccination followed by immunization with the Ad-Bal; (2) vaccination using the Ad-Bal vector followed by DNA vaccination; and (3) DNA vaccination followed by Ad-Bal infection and passive transfer of dendritic cells (DCs) infected with the Ad-Bal. Among the three protocols, the last gave the strongest humoral and cell-mediated immunity. These results suggest that the combination of DNA vaccination, Ad-Bal vector infection and passive transfer of Ad-Bal-infected DCs can induce strong immunity against HIV-1 Bal.

AIDS Vaccines↗
PubMed2001

Basaloid-squamous cell carcinoma of the esophagus: diagnosis based on immunohistochemical analysis.

Basaloid-squamous cell carcinoma of the esophagus (BSCC) is an extremely rare tumor. Histologically, this tumor should be differentiated from adenoid cystic carcinoma (ACC) and small cell undifferentiated carcinoma (SCUC). Biologically, this tumor is very aggressive, with a propensity for distant metastasis. We report a 64-year-old male with esophageal BSCC. The patient complained of dysphagia and was found to have a torous lesion in the esophagus on radiological examination. Upper gastrointestinal fiberscopy showed a localized ulcerative type tumor, which was diagnosed as squamous cell carcinoma (SCC) on biopsy. Surgery resulted in curative resection. A histological examination of the resected tumor showed features of BSCC. Immunohistochemical examination demonstrated AE3/1- and CAM 5.2-positive tumor cells, and laminin-positive cells in the periphery of the nests. These data were useful in differentiating this tumor from ACC and SCUC. Six months after surgery, the patient developed hepatic metastases, which were successfully treated by regional chemotherapy via the hepatic artery by using fluorouracil. The patient is currently being followed up at the outpatient clinic and shows no signs of any recurrence.

Biomarkers↗
PubMed2001

Electroconvulsive shock regulates serotonin transporter mRNA expression in rat raphe nucleus.

The antidepressive actions of electroconvulsive shock (ECS) therapy are considered to involve altered neurotransmission of serotonin. In this study, we investigated the effects of acute and chronic ECS on 5-hydroxytryptamine (5-HT) transporter mRNA expression in rat raphe nucleus. We found that serotonin transporter (5-HTT) mRNA expression was decreased in 9 and 24 h after acute ECS and in 3, 9, 24 h and 2 weeks after chronic ECS in rat raphe nucleus. We presume that the adaptive change in 5-HTT mRNA expression is possibly related to the therapeutic efficacy of electroconvulsive therapy (ECT) on medication-resistant depression.

Animals↗
PubMed2001

Thyrocyte integration, and thyroid folliculogenesis and tissue regeneration: perspective for thyroid tissue engineering.

The thyroid gland is composed of many ball-like structures called thyroid follicles, which are supported by the interfollicular extracellular matrix (ECM) and a capillary network. The component thyrocytes are highly integrated in their specific structural and functional polarization. In conventional monolayer and floating culture systems, thyrocytes cannot organize themselves into follicles with normal polarity. In contrast, in 3-D collagen gel culture, thyrocytes easily form stable follicles with physiological polarity. Integration of thyrocyte growth and differentiation results ultimately in thyroid folliculogenesis. This culture method and subacute thyroiditis are two promising models for addressing mechanisms of folliculogenesis, because thyroid-follicle formation actively occurs both in the culture system and at the regenerative phase of the disorder. The understanding of the mechanistic basis of folliculogenesis is prerequisite for generation of artificial thyroid tissue, which would enable a more physiological strategy to the treatment of hypothyroidism caused by various diseases and surgical processes than conventional hormone replacement therapy. We review here thyrocyte integration, and thyroid folliculogenesis and tissue regeneration. We also briefly discuss a perspective for thyroid tissue regeneration and engineering.

Animals↗