Biomedical subjects

T Toyoshima

Publications and source records attributed to T Toyoshima.

At least 19 recordsLinked to original sources

PubMed2006

Bite force, occlusal contact area and masticatory efficiency before and after orthognathic surgical correction of mandibular prognathism.

The purpose of this study was to evaluate bite force, occlusal contact area and masticatory efficiency before and after sagittal split ramus osteotomy in 27 patients with mandibular prognathism, in comparison with 27 control subjects with normal occlusion. Bite force and occlusal contact area were simultaneously measured with a computerized occlusal analysis system, the Dental Prescale system. Masticatory efficiency was estimated by a low-adhesive colour-developing chewing-gum system. The data were collected at initial medical consultation, immediately before surgery, and at 6 weeks, 3 months, 6 months, 1 year and more than 2 years after surgery. Both bite force and occlusal contact area of the patients before surgery were significantly less than those of the controls. Although all three parameters had improved after orthognathic surgery, the bite force and occlusal contact area did not reach the values of the controls within 2 years postoperatively; masticatory efficiency at 2 years after surgery drew near to control levels. Bite force correlated with occlusal contact area in the patients postoperatively, whereas masticatory efficiency did not correlate with either of the other two parameters. These results suggest that further adjustment of occlusion and mechanical advantage should be considered before the end of treatment.

Adolescent↗

PubMed2006

Expression of tumor-associated antigen RCAS1 and its possible involvement in immune evasion in oral squamous cell carcinoma.

BACKGROUND: RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is known to induce apoptosis in its receptor-positive cells. The authors investigated RCAS1 expression in oral squamous cell carcinoma (SCC) and its association with the apoptosis of tumor-infiltrating lymphocytes (TILs). METHODS: In 130 patients with oral SCC, the expression of RCAS1 in tumor cells was immunohistochemically examined and the apoptosis of TILs was examined by Terminal Deoxynucleotidyltransferase-mediated dUTP Nick End Labeling (TUNEL) staining. RESULTS: RCAS1 was detected both on the cytoplasm and the membrane of tumor cells in 41 of 130 cases (31.5%). Focusing on the expression at the invasive front interacting with host immune cells, RCAS1 was detected in 22 of 130 cases (16.9%). The percentage of TUNEL-positive TILs in cases with RCAS1-positive SCCs was significantly higher than in cases with RCAS1-negative SCCs (P < 0.0001). CONCLUSIONS: RCAS1 can be expressed on oral SCC cells and may be involved in the tumor escape from the host immune system by inducing the apoptosis of TILs.

Aged↗

PubMed2002

Inhibitor of cyclooxygenase-2 induces cell-cycle arrest in the epithelial cancer cell line via up-regulation of cyclin dependent kinase inhibitor p21.

Cyclooxygenase-2 is the rate-limiting enzyme in synthesis of prostaglandins and other eicosanoids. Prior reports have shown that inhibition of cyclooxygenase-2 activity, either by selective inhibitors or by antisense oligonucleotide, results in suppression of growth of squamous cell carcinoma cell lines which express high cyclooxygenase-2 levels, such as NA, a cell line established from a squamous cell carcinoma of the tongue. To investigate the mechanisms by which cyclooxygenase-2 inhibitors suppressed growth of these cells, the effects of NS-398, the selective cyclooxygenase-2 inhibitor, on cell-cycle distribution were examined. NS-398 induced G0/G1 cell-cycle arrest in NA cells which expressed cyclooxygenase-2. G0/G1 arrest induced by NS-398 was accompanied by up-regulation of cyclin-dependent kinase inhibitor p21, but not by up-regulation of the other cyclin-dependent kinase inhibitors. Transfection with p21 antisense oligonucleotide inhibited cell-cycle arrest induced by NS-398. Accumulation in G0/G1 was also observed in NA cells transfected with cyclooxygenase-2 antisense oligonucleotide. On the other hand, NS-398-treated NA cells showed a loss of plasma membrane asymmetry, a marker of early events in apoptosis. However, NS-398 did not induce other morphological and biochemical changes related to apoptotic cell death. These results suggest that cyclooxygenase-2 inhibitor induces G0/G1 cell-cycle arrest in NA cells by up-regulation of p21. Our results also suggest that NS-398 is not sufficient to complete the whole process of apoptosis in NA cells, although it induces an early event in apoptosis.

Apoptosis↗

PubMed2001

Specific inhibition of cyclooxygenase-2 results in inhibition of proliferation of oral cancer cell lines via suppression of prostaglandin E2 production.

Prostaglandins (PGs) are known to play important roles in the proliferation of various types of cancer cells. PGs are produced by the action of cyclooxygenase (COX) enzymes, and two forms of COX, COX-1 and COX-2, have been described. Previous studies have demonstrated that overexpression of COX-2 is associated with colon carcinogenesis, tumor invasion and metastatic potential of colon cancer. In this study, the role of COX-2 on proliferation of squamous cell carcinoma cell lines was investigated. NS-398, a selective COX-2 inhibitor, inhibited proliferation of NA cells, a squamous cell caricinoma cell line that constitutively expresses COX-2 mRNA. NS-398 suppressed the spontaneous production of PGE2 by NA cells, and the antiproliferative effect of NS-398 was abolished by addition of PGE2. Similar results were obtained from experiments using COX-2 antisense oligonucleotide. These results suggest that specific inhibition of COX-2 inhibits proliferation of cancer cells expressing COX-2 mRNA via suppression of PGE2 production.

Carcinoma, Squamous Cell↗

PubMed2001

Leakage of energy to the body surface during defibrillation shock by an implantable cardioverter-defibrillator (ICD) system--experimental evaluation during defibrillation shocks through the right ventricular lead and the subcutaneous active-can in canines.

The leakage of electrical current to the body surface during defibrillation shock delivery by an implantable cardioverter-defibrillator (ICD) device (the Medtronic Jewel Plus PCD system) was evaluated in 5 dogs. The defibrillation shocks were delivered between the active-can implanted in the left subclavicular region and the endocardial lead placed in the right ventricle at the energy levels of 1, 2, 8, 12, 24 and 34 J. During each delivery, the electrical current leakage from the body surface was measured by electrodes connected to a circuit at 4 recording positions: (A) parallel-subcutaneous (the electrodes were fixed in the subcutaneous tissue of the left shoulder and the right lower chest, and the direction of the electrode vector was parallel to the direction of the defibrillation energy flow); (B) cross-subcutaneous (the electrodes were fixed in the subcutaneous tissue of the right shoulder and the left lower chest, and the vector of the electrodes was roughly perpendicular to the direction of the energy flow); (C) parallel-surface (the electrodes were fixed with ECG paste on the shaved skin surface at the left shoulder and the right lower chest); and (D) surface grounded (the electrodes were fixed on the shaved skin surface at the left shoulder and the left foot, which was grounded). The circuit resistance was set at a variable level (100-5,000 ohms) in accordance with the resistance measured through each canine body. Leakage energies were measured in 750 defibrillation shocks with each circuit resistance in 5 dogs. The leakage energy increased in accordance with the increase of the delivered energy and the decrease of the circuit resistance in all 4 recording positions. When the circuit resistance was set at 1,000 ohms, the leakage energy during shock delivery at 34 J was 32+/-17 mJ at position A, 5+/-9 mJ at B, 10+/-9 mJ at C, and 4+/-3 mJ at D (p=0.042). The peak current was highest at position A and was 87+/-22 mA with a circuit resistance of 1,000 ohms. The power of the leakage energy depended on the delivered energy and the impedance between the electrodes. The angle between the alignment of the recording electrodes and the direction of the energy flow was another important factor in determining the leakage energy. Although the peak current of the leakage energy reached the level of macro shock, the highest leakage energy from the body surface was considerably less because of the short duration of the shock delivery.

Animals↗

PubMed2001

The contribution of low affinity NGF receptor (p75NGFR) to delayed neuronal death after ischemia in the gerbil hippocampus.

The implication of low affinity nerve growth factor receptor (p75NGFR), which is believed to play a pro-apoptotic role, in delayed neuronal death (DND) after ischemia in the gerbil hippocampus was investigated. Immunohistochemistry and Western blot analysis revealed that the presence of p75 NGFR immunoreactivity (IR) was negligible in the hippocampus of the sham control gerbil but appeared clearly in CA1 neurons 3 and 4 days after 5-min transient ischemia. Terminal deoxynucleotidyl transferase-mediated UTP nick end labeling (TUNEL) positive nuclei appeared when the level of p75NGFR IR increased. Furthermore, almost all TUNEL-positive CA1 neurons also costained for p75NGFR. These results suggest that p75NGFR contributes to DND after ischemia by an apoptotic mechanism.

Animals↗

PubMed2001

Collagen-binding domain of a Clostridium histolyticum collagenase exhibits a broad substrate spectrum both in vitro and in vivo.

The substrate spectrum of the tandem collagen-binding domain (CBD) of Clostridium histolyticumclass I collagenase (ColG) was examined both in vitro and in vivo. CBD bound to insoluble type I, II, III and IV collagens in vitro, and to skin, aorta, tendon, kidney, trachea and corneal tissues containing various types of collagen fibrils or sheets. CBD bound to all kinds of collagen fibrils regardless of their diameters and also bound to sheet-forming collagen in the glomerular basal lamina or Descemet's membrane of the cornea. This wide substrate spectrum expands possible applications of the drug delivery system we proposed previously (PNAS 95:7018-7023, 1998). Therapeutic agents fused with CBD will bind not only to subcutaneous tissues, but also to other tissues containing non-type I collagen.

Animals↗

PubMed2000

Identification of tranilast-binding protein as 36-kDa microfibril-associated glycoprotein by drug affinity chromatography, and its localization in human skin.

To elucidate the molecular mechanism involved in the suppression of keloids and hypertrophic scars by tranilast, we investigated the target protein of tranilast in bovine skin and aorta. A specific tranilast-binding protein was isolated from both tissues by drug affinity chromatography and was identified as 36-kDa microfibril-associated glycoprotein (36-kDa MAGP). Binding of 36-kDa MAGP to tranilast seemed to be specific since 36-kDa MAGP could be eluted from the drug affinity column by tranilast itself and also binding of 36-kDa MAGP to other anti-allergy drugs (amlexanox and cromolyn) is significantly weaker than that to tranilast. Light and electron microscopic immunohistochemistry detected the protein at the periphery of elastic fibers in normal human skin. In hypertrophic scar tissue, however, 36-kDa MAGP was located on small bundles of microfibrils. These findings provide support for the concept that elastogenesis occurs in scar tissue and 36-kDa MAGP might be one of the targets for tranilast.

Amino Acid Sequence↗

PubMed2000

Production of nitric oxide from endothelial cells by 31-amino-acid-length endothelin-1, a novel vasoconstrictive product by human chymase.

Human chymase selectively converts big endothelin (ET)-1 to 31-amino-acid-length ET-1 [ET-1(1-31)]. In this study we examined effect of ET-1(1-31) on endothelial function. ET-1(1-31) evoked contraction in a concentration-dependent manner at > 10(-8) M, which was about 10 times weaker than that of conventional ET-1 [ET-1(1-21)]. BQ485, an ETA receptor antagonist, completely abolished ET-1(1-31)-induced contraction, but BQ788, an ETB receptor antagonist, slightly enhanced it, suggesting that ET-1(1-31) relaxes artery via endothelium. On endothelial cells, ET-1(1-21) and ET-1(1-31) increased [Ca2+]i and produced NO, both of which were significantly inhibited by BQ788 and not by BQ485. These results indicate that ET-1(1-31) increased [Ca2+]i and produced NO in endothelial cells through ETB receptor similarly with ET-1(1-21), although slight difference in effect on smooth muscle cells.

Animals↗

PubMed2000

Paralytic toxins in a ribbon worm Cephalothrix species (Nemertean) adherent to cultured oysters in Hiroshima Bay, Hiroshima Prefecture, Japan.

In 1998, during the surveillance of the toxicity of various marine fouling organisms in Hiroshima Bay, Hiroshima Prefecture, Japan, specimens of the ribbon worm, "himomushi" Cephalothrix sp. (Nemertean) adherent to the shells of cultured oysters hanging onto floating culture rafts were found to contain toxins which showed strong paralytic action in mice throughout the survey period, February to May. The maximum toxicity (as tetrodotoxin, TTX) was 14,734 MU/g whole body. Attempts were made to identify the paralytic toxins in this worm. The "himomushi" toxin (HMT) was extracted from the worm with 80% methanol acidified with acetic acid and the extract defatted with dichloromethane. The aqueous layer was chromatographed on activated charcoal and the unbound and bound toxic fractions were analyzed by high-performance liquid chromatography and gas chromatography-mass spectrometry. It was rather unexpectedly revealed from these results that HMT was comprised of TTX, 4-epiTTX, anhydroTTX and three unidentified toxins. To our knowledge, this is the first report of the occurrence of toxic organisms, containing a high concentration of TTX, adherent to cultured bivalves such as oysters.

Animals↗

PubMed2000

Magnetic resonance coronary angiography in patients with ischemic heart disease: analysis of coronary arterial blood flow velocity pattern.

Only a few reports evaluating coronary arterial blood flow velocity patterns using magnetic resonance (MR) coronary angiography have appeared to date. This study reports an evaluation of coronary arterial blood flow velocity patterns in patients with ischemic heart disease and in healthy subjects using MR coronary angiography. The subjects consisted of 20 patients with ischemic heart disease (IHD group) and 20 normal healthy subjects (N group). Using the fCARD PC method, ECG-gated MR coronary angiography was performed using an anteroposterior opposing phased array coil. Regions of interest were placed on bilateral coronary arteries to measure coronary arterial blood flow velocity patterns. The IHD group was divided into two subgroups, based on the presence (MI group) or absence (AP group) of infarcted myocardium using 99m Tc-methoxyisobutylisonitrile (MIBI) myocardial scintigraphy. Average diastolic peak velocity (ADPV) was lower in the IHD group than in the N group. In addition, the diastolic / systolic velocity ratio (DSVR) was significantly lower in the MI group. Moreover, in the AP group, both the ADPV and DSVR values were significantly increased in those who had undergone percutaneous transluminal coronary angioplasty postoperatively. Different from the Doppler guidewire method, MR coronary angiography facilitates noninvasive evaluation of coronary arterial blood flow velocity. Therefore, these results indicate that MR coronary angiography represents a potentially useful technique for diagnosing lesions of coronary arteries and evaluating their functions. This noninvasive method can be expected to replace the invasive Doppler guidewire method in the near future with development of MR coronary angiography technology.

Aged↗

PubMed2000

Patient with atrioventricular node reentrant tachycardia with eccentric retrograde left-sided activation: treatment with radiofrequency catheter ablation.

We describe a patient with supraventricular tachycardia with triple atrioventricular (AV) node pathway physiology. A discontinuous curve was present in the antegrade AV nodal function curves. During right ventricular pacing, the earliest retrograde atrial activation was recorded at the left-sided coronary sinus electrode. The retrograde ventricular-atrial interval was long and had decremental conduction. We induced a slow-slow AV node reentrant tachycardia (AVNRT) with eccentric retrograde left-sided activation. After slow pathway ablation, dual AV nodal pathway physiology was present. AVNRT with eccentric retrograde left-sided activation is relatively rare, and our findings suggest that eccentric retrograde left-sided atrial inputs consist partially of a slow pathway and disappear with slow pathway ablation.

Atrial Function, Left↗

PubMed2000

Treatment with low-dose cytosine arabinoside followed by administration of macrophage colony-stimulating factor prolongs the survival of patients with RAEB, RAEB-T, or leukemic phase myelodysplastic syndrome: a pilot study.

The treatment of patients with aggressive subclasses of myelodysplastic syndrome (MDS) remains a challenge. In an effort to improve the survival of patients with refractory anemia with excess blasts (RAEB), RAEB in transformation (RAEB-t), or acute myelogenous leukemia transformed from MDS (MDS-AML), we conducted a small trial in which 28 such patients were treated with low-dose cytosine arabinoside (LDAraC) followed by administration of macrophage colony-stimulating factor (M-CSF). The overall rate of response to the treatment was 61%, including 39% with a complete response, which is higher than rates obtained in previous studies in which LDAraC alone was administered to patients with MDS. Median survival was 23.5 months in cases of RAEB, 16.7 months in cases of RAEB-t, and 19.7 months in cases of MDS-AML. The overall survival of the study group appeared to be prolonged in comparison with a historical control group of patients treated with LDAraC alone. It is suggested that M-CSF added to the administration of LDAraC plays an active role in the therapy. No therapy-related death occurred. Some unique actions of M-CSF were suggested in this trial. It is concluded that therapy with LDAraC + M-CSF is a useful treatment option for patients with aggressive subclasses of MDS and MDS-AML to provide better response and survival.

Adult↗

PubMed2000

[A case of peripelvic extravasation related to pregnancy].

A 35-year-old woman was hospitalized at 39 weeks 0 days of gestation because of acute left flank pain. Magnetic resonance imaging (MRI) revealed bilateral hydronephrosis with peripelvic extravasation of contrast material around the left kidney. The pregnancy ended with a cesarean section and after the cesarean section a left double-J-stent was placed cystoscopically. An excretory urogram following the removal of the ureteral stent showed no extravasation or hydronephrosis in either kidney.

Adult↗

PubMed1999

Nitric oxide up-regulates the expression of intercellular adhesion molecule-1 on cancer cells.

Nitric oxide (NO) is an unstable free radical that functions as a cytotoxic agent secreted by macrophages to kill cancer cells. Here we report the effect of NO on the expression of intercellular adhesion molecule-1 (ICAM-1) on cancer cells. NO donors such as SNP, SNAP and SIN-1 up-regulated the expression of ICAM-1 on NA cells, a squamous cell carcinoma cell line. Northern blot analysis showed that the induction of ICAM-1 might be due to transcriptional induction of ICAM-1 mRNA. Up-regulation of ICAM-1 mRNA by NO donors was inhibited by carboxy-PTIO, a NO scavenger. Although NF-kappaB activity was induced by NO donors, AP-1 was not induced by them. Staurosporin, a protein kinase C (PKC) inhibitor, inhibited the induction of ICAM-1 on NA cells by NO, whereas genistein, a protein tyrosine kinase inhibitor, did not. These findings indicate that NO up-regulates ICAM-1 expression on cancer cells by a regulatory mechanism involving PKC and suggest that NF-kappaB, but not AP-1, might be involved in induction of ICAM-1 by NO in cancer cells.

Benzoates↗

PubMed1999

Re-evaluation of sexual dimorphism in human corpus callosum.

To study the sexual dimorphism of human corpus cauosum (CC), we analyzed the midsaggital magnetic resonance imaging (MRI) morphometry in 67 adults aged (mean+/-s.d.) 36.82+/-9.35 years. Four specific angles of the CC were determined. All four angles in 34 females and 33 age-matched males showed a significant difference between females and males. These morphometric findings confirm a gender difference in the orientation of corpus callosum.

Adult↗

PubMed1999

The chronic cell death with DNA fragmentation after post-ischaemic hypothermia in the gerbil hippocampus.

The long-term effects of post-ischaemic hypothermia are controversial. The purpose of this study was to examine the long-term effects of post-ischaemic hypothermia on neuronal survival in gerbils in terms of morphology and function. Hypothermia was induced at 32 degrees C for 4 h immediately after ischaemia. Examination was performed at 1 week and at 1 month after ischaemia. Post-ischaemic hypothermia prevented CA1 neuronal damage 1 week after ischaemia. At 1 month after ischaemic insult, however, the degree of the protective effect of post-ischaemic hypothermia was reduced in the lateral and medial CA1 areas. DNA fragmentation was also observed at 1 month. The errors in the 8-arm radial maze trial were increased at 1 month. These data may indicate that cells in the CA1 area are very vulnerable to ischaemia and die after post-ischaemic hypothermia, and that their death is associated with apoptosis.

Analysis of Variance↗

PubMed1999

Burch bladder neck suspension for cystocele repair: the necessity of combined vaginal procedures for severe cases.

BACKGROUND: Burch operation is an accepted form of bladder neck suspension for small cystoceles. The purpose of the present study was to evaluate the efficacy of Burch repair for severe cystoceles compared with Burch repair along with vaginal procedures. METHODS: A total of 14 patients with severe cystocele (grade III-IV) treated with open Burch operation were evaluated retrospectively. Of these patients, eight were Burch only and the remaining six underwent combined Burch with vaginal repair (anteroposterior vaginal wall plasty and hysterectomy). RESULTS: After a mean follow up of 40 months (range 6-80), cystocele recurred in one patient at 1 month, and rectocele became prominent in three patients, including one who also presented uterine prolapse among the Burch-only group. Conversely, all six patients who underwent the combined operation showed no occurrence of cystocele or rectocele. The proportion of patients not failing treatment was significantly higher in the combined operation group than in the Burch-only group. Intermittent self-catheterization was needed in one patient from the combined operation group for 6 months, but all other patients had restored smooth urination within a few weeks after the operation. CONCLUSIONS: The results suggest that, for severe cystoceles, Burch-only repair is insufficient and combined Burch with vaginal repair should be used to manage various pelvic hypermobility symptoms.

Aged↗