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T Sasano

Publications and source records attributed to T Sasano.

At least 19 recordsLinked to original sources
PubMed2006

Morphological and histopathological changes in tongues of experimentally developed acromegaly-like rats.

An acromegaly-like rat model recently developed by exogenous administration of insulin-like growth factor I (IGF-I) was used to investigate morphological and histopathological tongue changes and clarify whether the changes were reversible. Human recombinant IGF-I (640 microg/day) was continuously subcutaneously infused into ten-week-old male rats for four weeks (IGF-I group; n = 6). Control sham-operated animals were injected saline alone (control group; n = 6). Rats were sacrificed immediately on ending administration at the age of fourteen weeks. Another 12 rats (6 from each group) were housed for an additional four weeks after administration ended. Total IGF-I (human + rat) increased significantly during administration, returning to control levels afterwards. Tongue weights significantly increased with histopathological changes present (increases in the muscle-bundle width, spaces between muscle-bundles and epithelium thickness) in the IGF-I group compared to control rats. Tongue size returned to control levels after discontinuation of IGF-I administration. These findings suggest that the characteristic tongue enlargement was developed experimentally in our acromegaly-like rat model, and that such morphological and histopathological tongue changes are reversible on normalization of circulating IGF-I levels.

Acromegaly↗
PubMed2006

Toll-like receptors, NOD1, and NOD2 in oral epithelial cells.

Oral epithelium might be the first barrier against oral bacteria in periodontal tissue. We hypothesized that oral epithelium is endowed with innate immune receptors for bacterial components, which play roles in host defense against bacterial infection without being accompanied by excessive inflammatory responses. We found clear expression of Toll-like receptor (TLR)4 as well as TLR2, and strong expression of NOD1 and NOD2 in normal oral epithelial tissues by immunohistochemical analysis. We also showed that primary oral epithelial cells in culture expressed these molecules using PCR, flow cytometry, and immunostaining. In inflamed oral epithelium, cell-surface localizations of TLR2 and TLR4 were more clearly observed than in healthy tissue. Upon stimulation with synthetic ligands for these receptors, the expression of beta-defensin 2 was markedly up-regulated. These findings indicate that these molecules in oral epithelial cells are functional receptors that induce antibacterial responses.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Evaluation of the position, mobility, and morphology of the disc by MRI before and after four different treatments for temporomandibular joint disorders.

OBJECTIVES: The purpose of this study was to evaluate changes in disc position, mobility, and morphology in patients with temporomandibular joint disorders (TMD) in response to four different treatments, splint therapy, pumping manipulation, arthrocentesis, and arthroscopic surgery, using magnetic resonance imaging (MRI). METHODS: Eighty-five joints (85 patients) with unilateral internal derangement or osteoarthritis that were successfully treated were included in this study. The patients were divided into four groups as follows: splint therapy group, pumping manipulation group, arthrocentesis group, and arthroscopic surgery group. Changes in the disc position, mobility, and morphology before and after treatment were compared among the four groups using MRI. RESULTS: All discs showed anterior disc displacement (ADD) without reduction before treatment. Only 10% of the joints became ADD with reduction after treatment, and the other joints remained ADD without reduction in spite of treatment. Discs treated by arthroscopic surgery were located more anteriorly compared with pre-treatment. In pre-treatment MRI, the rate of stuck disc increased as the stage of the treatment advanced. In post-treatment MRI, all temporomandibular joints (TMJs) had mobile discs. The disc deformity advanced after arthrocentesis and arthroscopic surgery. CONCLUSIONS: Even though clinical signs and symptoms were alleviated by treatment, most discs remained ADD without reduction on MRI in spite of treatment. This suggests that the four treatments do not necessarily improve the position and deformity of the disc, and that arthroscopic surgery advances the deformity and anterior displacement of the disc. Disc mobility is important for improving clinical signs and symptoms.

Adolescent↗
PubMed2005

Chemically synthesized pathogen-associated molecular patterns increase the expression of peptidoglycan recognition proteins via toll-like receptors, NOD1 and NOD2 in human oral epithelial cells.

Peptidoglycan recognition proteins (PGRPs), a novel family of pattern recognition molecules (PRMs) in innate immunity conserved from insects to mammals, recognize bacterial cell wall peptidoglycan (PGN) and are suggested to act as anti-bacterial factors. In humans, four kinds of PGRPs (PGRP-L, -Ialpha, -Ibeta and -S) have been cloned and all four human PGRPs bind PGN. In this study, we examined the possible regulation of the expression of PGRPs in oral epithelial cells upon stimulation with chemically synthesized pathogen-associated molecular patterns (PAMPs) in bacterial cell surface components: Escherichia coli-type tryacyl lipopeptide (Pam3CSSNA), E. coli-type lipid A (LA-15-PP), diaminopimelic acid containing desmuramyl peptide (gamma-D-glutamyl-meso-DAP; iE-DAP), and muramyldipeptide (MDP). These synthetic PAMPs markedly upregulated the mRNA expression of the four PGRPs and cell surface expression of PGRP-Ialpha and -Ibeta, but did not induce either mRNA expression or secretion of inflammatory cytokines, in oral epithelial cells. Suppression of the expression of Toll-like receptor (TLR)2, TLR4, nucleotide-binding oligomerization domain (NOD)1 and NOD2 by RNA interference specifically inhibited the upregulation of PGRP mRNA expression induced by Pam3CSSNA, LA-15-PP, iE-DAP and MDP respectively. These PAMPs definitely activated nuclear factor (NF)-kappaB in the epithelial cells, and suppression of NF-kappaB activation clearly prevented the induction of PGRP mRNA expression induced by these PAMPs in the cells. These findings suggested that bacterial PAMPs induced the expression of PGRPs, but not proinflammatory cytokines, in oral epithelial cells, and the PGRPs might be involved in host defence against bacterial invasion without accompanying inflammatory responses.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2004

Platelet responses and anaphylaxis-like shock induced in mice by intravenous injection of whole cells of oral streptococci.

Intravenous injection of lyophilized whole cells of various oral streptococcal strains into muramyldipeptide (MDP)-primed C3H/HeN mice induces rapid anaphylactoid shock. Here we examined the mechanism underlying this shock. In non-primed mice, Streptococcus intermedius K-213K (SiK213) and Streptococcus constellatus T21 (ScT21) produced little or no sign of shock. In MDP-primed mice, SiK213 caused lethal shock, while ScT21 only had a weak effect. SiK213 induced decreases in blood platelets and 5-hydroxytryptamine (5HT) preceding the shock, while the effects of ScT21 were weak. The SiK213-induced 5HT decrease and shock were reduced by a complement-C5 inhibitor. These results suggest that (i). streptococcal bacterial cells can induce rapid platelet responses, (ii). complement-dependent degradation of platelets may be involved in streptococcus-induced shock, (iii). the streptococcus-induced platelet degradation or degranulation may occur largely in the systemic circulation, and (iv). platelets may play a role not only in infectious diseases caused by gram-negative bacteria, but also in diseases caused by gram-positive bacteria.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed2004

Insulin-like growth factor-I stimulates acromegaly-like specific mandibular enlargement in rats.

To help us investigate the time course of mandibular enlargement in acromegaly or acrogiantism to determine the most suitable period for occlusal treatment in this disease, our aim was to develop a rat model of acromegaly (acrogiantism). In this study, prominent mandibular enlargement was induced by continuous subcutaneous infusion of human recombinant insulin-like growth factor-I (IGF-I) (640 microg/day) in 10-week-old male rats for 4 weeks (n = 6); the control sham-operated group was injected with saline alone (n = 6). Circulating human IGF-I was clearly detectable in the IGF-I group during the four-week administration period, while endogenous rat IGF-I levels decreased. Total IGF-I (human + rat) increased significantly during administration, returning to control levels afterwards. The length of every bone examined (mandible, maxilla, and femur) showed a significant increase compared to control rats, especially the mandible. Although the mandible did not continue to grow after discontinuation of IGF-I administration, it did not return to control size, unlike the maxilla and femur, and disharmonious jaw size (between maxilla and mandible) persisted even after circulating IGF-I levels normalized. These findings in our rat model suggest that mandibular occlusal treatment should only be considered for acromegalic (acrogiantic) patients after serum IGF-I levels have normalized and bone growth has ceased.

Acromegaly↗
PubMed2003

A simple, yet accurate method for detecting and quantifying secretions from human minor salivary glands using the iodine-starch reaction.

The lack of published information about the minor salivary glands is due in part to the difficulties experienced in collecting and quantifying their secretions. In fact, no method exists for measuring their secretions that is both simple and accurate. This investigation examined the accuracy of our newly developed method (which simply employs the iodine-starch reaction) in 10 healthy non-medicated adults. A strip painted with a solution of iodine in absolute alcohol then with a fine starch powder mixed with castor oil was placed at a designated location on the lower-lip mucosa for 2 min to collect saliva. Black-stained spots of various sizes corresponding to the individual glands could be accurately visualized. After removal of the strip, the total stained area (mm2) was calculated by digitizing the spot areas using a computer system. The correlation coefficient (r) between known volumes of saliva and stain size was 0.995, indicating a close correlation. The correlation coefficient (r) between area values obtained in the first trial in each subject (Y) and the second (X; 10 min later) was 0.963, and the simple regression equation was close to Y=X, indicating good reproducibility. The mean flow rate microl/cm2 per min) obtained by converting mean total area to volume and thence to flow rate was 0.49+/-0.26, in good agreement with published values obtained by others. These results suggest that our newly developed method allows both the distribution and secretion rate of the minor salivary glands to be observed, and that it should be of practical value due to its simplicity, accuracy, and reproducibility.

Adult↗
PubMed2003

Centrally mediated reflex vasodilation in the gingiva induced by painful tooth-pulp stimulation in sympathectomized human subjects.

This study was designed to determine whether painful electrical stimulation of the tooth pulp induces centrally mediated reflex vasomotor changes in human gingiva and whether the sympathetic nervous system is involved in the vasomotor responses. Dynamic changes in maxillary gingival blood flow (GBF) following painful electrical stimulation of the mandibular lateral incisor were investigated, by means of laser-Doppler flowmetry, in both healthy volunteers and patients undergoing sympathetic blockade for hyperhidrosis. Increases in GBF were observed in both healthy volunteers and patients on the ipsilateral side without an increase in systemic blood pressure, but the evoked GBF increase disappeared when pain sensation was abolished by local anesthetization with 2% xylocaine solution. The vasodilator responses did not differ in amplitude between before and after the sympathectomy. These results suggest that painful tooth stimulation evokes centrally mediated reflex vasodilation, presumably via parasympathetic efferent fibers, in the human gingiva and that sympathetic vasomotor mechanisms are not involved in these responses.

Adult↗
PubMed2003

Usefulness of heavily T(2) weighted magnetic resonance images for the differential diagnosis of parotid tumours.

OBJECTIVES: To evaluate the usefulness of heavily T(2) weighted (T2W) magnetic resonance (MR) images for the differential diagnosis of parotid tumours. METHODS: Conventional T2W and heavily T2W images obtained from 43 patients with parotid tumours were reviewed retrospectively. Tumours were classified pathologically into three types: pleomorphic adenoma (25 cases), Warthin's tumour (7 cases) and malignant tumour (11 cases). During interpretation of each MR image, special attention was paid to the homogeneity and signal intensity displayed by the solid portions of the tumours. RESULTS: Heavily T2W images could distinguish pleomorphic adenoma from Warthin's tumour and malignant tumours based on the homogeneity and signal intensity of the solid portions, whereas conventional T2W images could not. On conventional T2W images, neither homogeneity nor signal intensity differed significantly among these three tumour types. On heavily T2W images, malignant and Warthin's tumours appeared more homogeneous than pleomorphic adenoma (P<0.0061); signal intensity from pleomorphic adenoma was significantly different to signal intensity from malignant tumours (P<0.05) and Warthin's tumour (P<0.005). CONCLUSIONS: Heavily T2W MR images can be useful in distinguishing pleomorphic adenoma from Warthin's tumour and malignant tumours.

Adenocarcinoma↗
PubMed2002

Dependence of pulpal blood-flow responses on baseline blood-flow in the cat.

It has been shown earlier that electrical stimulation of the distal cut end of the inferior alveolar nerve (IAN) in the cat evokes three different patterns of pulpal blood-flow (PBF) response in the ipsilateral mandibular canine tooth (a decrease, a biphasic response, or an increase). The response to a given stimulus sometimes changed to another pattern even in one and the same experimental animal during the course of the experiment. It is known that the evoked decrease is due to activation of the sympathetics and that the increase is due to antidromic activation of sensory fibres; but, it is unknown why the response varies so much. It is hypothesised that the baseline blood-flow (BBF) modulates vasomotor responses in the dental pulp. To test this hypothesis, the effects of BBF on PBF responses elicited by the IAN stimulation mentioned above were investigated. Dynamic changes in PBF in cat mandibular canine teeth were elicited by electrical stimulation of the distal cut end of the IAN, at various BBF, with blood-flow monitored by laser Doppler flowmetry. The amplitude of the PBF vasodilator response increased as BBF was adjusted downwards (by cooling the tooth). In contrast, the amplitude of the PBF vasoconstrictor response increased as the BBF rose. Vasodilator responses could be transformed into vasoconstrictor responses, and vice versa, by alterations in the BBF. No systemic blood-pressure changes were elicited throughout the experiment. These results indicate that a consideration of baseline vascular tone is important, whenever the size of PBF responses to various stimuli is discussed or calculated.

Animals↗
PubMed2001

Catheter ablation of idiopathic left ventricular tachycardia with multiple breakthrough sites guided by an electroanatomical mapping system.

Idiopathic ventricular tachycardia (VT) has been considered to be amenable to radiofrequency catheter ablation guided by Purkinje potentials. However, there appear to be various types of reentrant circuits associated with this VT deduced from the results of the successful radiofrequency catheter ablation cases. We describe in this report a patient with idiopathic left ventricular tachycardia which was electrically inducible and verapamil sensitive. Multiple earliest ventricular activation sites during tachycardia were detected with electroanatomical mapping using the CARTO system. Multiple applications at these sites failed to eliminate the VT. The earliest Purkinje potential was recorded at least 1.5 cm away from the earliest ventricular activation sites, and the radiofrequency current application at this site resulted in the complete abolition of this VT. The reentrant circuit of this tachycardia seemed to have multiple breakthrough sites to the ventricular myocardium, which were distant from the requisite part of the reentrant circuit of this VT involving the Purkinje fiber network conduction system.

Adult↗
PubMed2001

Evaluation of pulse sequences used for magnetic resonance sialography.

OBJECTIVES: To determine the most appropriate sequences for the visualization of small parotid ducts in MR sialography. METHODS: MR images of a phantom consisting of distilled water in polyethylene tubes were obtained with turbo-spin echo (TSE), single-shot turbo-spin echo (SSTSE), half-fourier acquisition, single-shot turbo-spin echo (HASTE) and turbo gradient-spin echo (TGSE) pulse sequences and compared visually and quantitatively. MR sialograms obtained from healthy volunteers and patients with Sjögren's syndrome (SS) were obtained using the same four sequences. RESULTS: In the phantom, TSE images were best and the contrast-noise ratio (CNR) highest. In the volunteers, the main ducts were especially clearly visualized with TSE and in SSTSE; however, the majority of secondary and/or tertiary parotid ducts were not depicted by any of the sequences used. In SS patients, images of small main ducts and small pseudocysts were clearer using TSE. However, TSE could not depict the narrow main ducts or peripheral ducts or very small pseudocysts. CONCLUSIONS: TSE is considered the most suitable MR sequence for assessing small parotid gland ducts. However, further improvement is needed since it does not always visualize them sufficiently.

Adult↗
PubMed2001

Serious arrhythmias in patients with apical hypertrophic cardiomyopathy.

We report cases of serious arrhythmias associated with apical hypertrophic cardiomyopathy (AHCM). Thirty-one patients were referred to our institute to undergo further assessment of their AHCM from 1988 to 1999. Three patients with nonsustained ventricular tachycardia demonstrated an 123I-MIBG regional reduction in the tracer uptake. In two patients with ventricular fibrillation (VF), the findings from 123I-MIBG imaging revealed regional sympathetic denervation in the inferior and lateral regions. Electrophysiologic study demonstrated reproducible induction of VF in aborted sudden death and presyncopal patients, resulting in the need for an implantable defibrillator device and amiodarone in each patient. Patients with refractory atrial fibrillation with a rapid ventricular response suffered from serious congestive heart failure. A prudent assessment and strategy in patients with this disease would be indispensable in avoiding a disastrous outcome.

3-Iodobenzylguanidine↗
PubMed2000

Low-dose continuous indomethacin in early days of age reduce the incidence of symptomatic patent ductus arteriosus without adverse effects.

We conducted a comparative study to evaluate whether the low-dose continuous indomethacin therapy in the early days of age would reduce incidence of the symptomatic patent ductus arteriosus (PDA) without the adverse effects. Thirty-seven infants were in the historical comparison group, and 39 infants were given low-dose indomethacin continuously (0.004 mg/kg/h) from 6-12 postnatal hours until the recognition of closing PDA. Low-dose continuous indomethacin significantly decreased the incidence of symptomatic PDA at 5 days of age (p < 0.01) as compared with the historical comparison group. There was no episode of decreasing urinary output and necrotizing enterocolitis in the indomethacin group. We conclude that the low-dose continuous indomethacin therapy results in decreasing the incidence of symptomatic PDA without significant adverse reactions.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Repeated acute hypoxia temporarily attenuates the ventilatory respiratory response to hypoxia in conscious newborn rats.

We asked whether repeated hypoxic exposures during the early neonatal periods could affect the ventilatory control, such as the lung volume-dependent ventilatory inhibition (HBR), pulmonary ventilation (VE), and CO2 production (VCO2). Within each litter of rats, one group of pups (experimental group H) was exposed to 6% O2 (30-min duration twice a day from postnatal d 1 to 4). The other group (control group C) was exposed to air. At 5 d after birth, the HBR was triggered by lung inflation via negative body surface pressure (10 cm H2O). Measurements of VE and VCO2 were done by plethysmography and the inflow-outflow CO2 difference, respectively. At 2 wk of age, VE and VCO2 measurements were repeated by the barometric technique and the inflow-outflow CO2 difference, respectively. Each conscious pup was breathing normoxia (21% O2) and then hypoxia (10% O2). Results were as follows: 1) during normoxia, HBR was stronger and both VE and VCO2 were higher in H pups than in C pups; 2) during hypoxia, the HBR of C was as in normoxia, whereas that of H was increased above the normoxic value; 3) during hypoxia, C maintained VE, whereas H decreased it; 4) in hypoxia, VCO2 was reduced significantly in both groups; 5) at 2 wk of age, VE and VCO2 did not differ between H and C during normoxia or in response to 10% hypoxia. We conclude that in rat pups, repeated hypoxic episodes can modify the HBR and, at least temporarily, reduce the VE response to hypoxia with a decrease in VCO2. The findings are in agreement with the view that repeated hypoxic exposures in the neonatal period could interfere with the development of respiratory control and could possibly be involved in the mechanisms of neonatal apnea or sudden infant death syndrome.

Animals↗
PubMed1999

Diastolic potentials observed in idiopathic left ventricular tachycardia.

Radiofrequency catheter ablation (RF-CA) has demonstrated a high success rate in eliminating idiopathic left ventricular tachycardia (ILVT), and the target site is determined by the score of pace mapping or the Purkinje potential (PP) preceding the onset of the ventricular activation, which is considered to indicate the exit site of the reentrant circuit. However, only a few reports have described the potential obtained from the slow conduction zone. RF-CA was successfully performed in 8 patients with ILVT. Careful mapping of the left ventricle during tachycardia was carried out to find the diastolic potential (DP). A DP was obtained in 4 patients (group 1), but not in 4 others (group 2). The local electrogram was recorded from the distal tip of the ablation catheter during the RF current application in order to investigate the pattern of termination of ILVT. A DP was recorded at the point where the catheter was slightly pulled back to a site proximal to the exit site of the reentrant circuit at the left interventricular basal septum. In group 1, conduction block between the DP and PP eliminated ILVT in 3 out of 4 cases, and 1 case showed conduction block between the DP and ventricular potential. In 2 out of 4 patients in group 2, the local electrogram showed conduction block between PP and the ventricular potential when VT terminated. The ablation site in group 1 was located relatively more basal than that in group 2 in anatomy. A DP was obtained in a half of the cases with ILVT and RF-CA at this site could eliminate ILVT. A DP was obtained at a site relatively basal to the exit of the reentrant circuit and it is considered that this is a useful marker in terms of the successful ablation of ILVT.

Adolescent↗
PubMed1999

Linearly and circularly polarized, 50 Hz magnetic fields did not alter intracellular calcium in rat immune cells.

This study was conducted to determine if exposure to 50 Hz magnetic field (MF) affects intracellular calcium ([Ca2+]i). We employed flow cytometry for real-time detection of possible changes in [Ca2+]i in a large number of cells. A solenoid coil for vertical MF exposure and a multiple-loop square-coil for horizontal MF were utilized. In the laboratory, background 50 Hz MF was less than 0.08 microT when all necessary equipment was powered. Rat thymocytes were exposed to 0.1 mT horizontal or vertical field, or to 0.14 mT circularly polarized field for 30 min; the effects of consecutive exposures to vertical and horizontal MFs, or vice versa, for 20 min each also were examined. In addition, intact thymocytes or lectin-activated thymocytes, splenocytes and peripheral blood lymphocytes were exposed to the 5 mT vertical field for 30 min. In all these experiments, no alteration in [Ca2+]i was evident. As a positive control, a calcium ionophore always was added to the medium following MF exposure to verify that the cells were capable of increasing [Ca2+]i and the system would record the response. The data indicate that MF exposure had no effect on [Ca2+]i under any of the conditions examined.

Animals↗