Biomedical subjects

K Sumiyoshi

Publications and source records attributed to K Sumiyoshi.

At least 19 recordsLinked to original sources

PubMed2006

Neutrino signals from the formation of a black hole: A probe of the equation of state of dense matter.

The gravitational collapse of a nonrotating, black-hole-forming massive star is studied by nu-radiation-hydrodynamical simulations for two different sets of realistic equation of state of dense matter. We show that the event will produce as many neutrinos as the ordinary supernova, but with distinctive characteristics in luminosities and spectra that will be an unmistakable indication of black hole formation. More importantly, the neutrino signals are quite sensitive to the difference of equation of state and can be used as a useful probe into the properties of dense matter. The event will be unique in that they will be shining only by neutrinos (and, possibly, gravitational waves) but not by photons, and hence they should be an important target of neutrino astronomy.

Journal Article↗

PubMed2006

Efficacy and safety of nurse-administered propofol sedation during emergency upper endoscopy for gastrointestinal bleeding: a prospective study.

BACKGROUND AND STUDY AIMS: Recent studies have documented the safety of propofol sedation for endoscopic procedures, but many endoscopists are reluctant to use propofol for high-risk patients because of adverse effects. The aim of this study was to demonstrate the safety and efficacy of nurse-administered propofol sedation during emergency upper endoscopy for patients with gastrointestinal bleeding. PATIENTS AND METHODS: Over a period of 18 months, 120 patients suffering from acute upper gastrointestinal bleeding received propofol sedation administered by a registered nurse. Among these, 15 patients were classified into American Society of Anesthesiologists (ASA) class IV, 84 were ASA class III, and 21 were ASA class II. Patients without gastrointestinal bleeding, who also received propofol during the same period and were matched for age, gender, and ASA class, served as controls. RESULTS: Endoscopic hemostasis was achieved in 98.3 % of patients, and 97.5 % were satisfied with the procedure. In patients with gastrointestinal bleeding, the rates of hypotension (systolic blood pressure < 90 mmHg) and hypoxemia (peripheral oxygen saturation < 90 %) were 8.3 % and 6.7 % respectively, values higher than those in the control group. However, neither mask ventilation nor endotracheal intubation was necessary. Although two patients with gastrointestinal bleeding developed pneumonia, most likely due to aspiration during the procedure, they recovered within 5 days of treatment. There were no sedation-associated severe complications or mortalities. CONCLUSION: Using a strict protocol designed to protect the patient's airway and cardiovascular function, nurse-administered propofol sedation during emergency upper gastrointestinal endoscopy is safe and appropriate in cases of acute gastrointestinal bleeding.

Acute Disease↗

PubMed2003

Smads regulate collagen gel contraction by human dermal fibroblasts.

BACKGROUND: Transforming growth factor (TGF)-beta induces fibroblast contraction that is implicated in efficient wound healing. The Smad family of proteins mediates signal transduction of the TGF-beta superfamily. However, its role in fibroblast contraction remains unclear. OBJECTIVES: To determine whether Smad proteins regulate fibroblast contraction. METHODS: We used an in vitro type I collagen gel contraction assay with human dermal fibroblasts infected with adenoviruses carrying Smads. RESULTS: Overexpression of Smad3, a major signal transducer in the Smad family, enhanced collagen gel contraction by fibroblasts when compared with fibroblasts overexpressing a control lacZ. Addition of a very low concentration of TGF-beta1 that did not affect the collagen gel contraction by itself enhanced the contraction by fibroblasts overexpressing Smad3. In contrast, TGF-beta1-mediated collagen gel contraction was suppressed by overexpression of Smad7, a major inhibitory regulator in the Smad family, in fibroblasts. In addition, inhibitors of the Erk and p38 pathways, PD98059 and SB203580, did not affect TGF-beta1-mediated collagen gel contraction by dermal fibroblasts. CONCLUSIONS: Modulation of Smad3 or Smad7 expression in dermal fibroblasts affected their contraction of collagen gels possibly by regulating TGF-beta signalling in fibroblasts.

Blotting, Western↗

PubMed2003

Pressure-pain threshold of oral mucosa and its region-specific modulation by pre-loading.

Once subjected to denture wearing, oral mucosa has to withstand mechanical loads of various levels and durations. However, how this load affects oral mucosal sensitivity is unknown. This study investigated the pressure-pain threshold (PPT) of oral mucosa with or without pre-loading. An electric pressure algometer was developed specifically for measuring the PPT of oral mucosa. Measurements of 10 dentulous maxillae showed that the baseline PPT (BPPT) of the palatal site was 4.9- and 3.7-fold greater than that of the labial or buccal sites, respectively. The PPT of the labial site decreased significantly compared with its BPPT after 2 s-100% BPPT and 5 s-100% BPPT pre-loading. The PPT of the palatal site increased after 5 s-50% BPPT and 5 s-80% BPPT and 0.2 s-100% BPPT and 2 s-100% BPPT pre-loading. The PPT of the buccal site did not change after all levels and durations of pre-loadings tested. These results indicated the disproportionate modulation of oral mucosal PPT following various loads, suggesting that oral mucosa possesses region-specific psychophysical tolerance to mechanical stimuli.

Adult↗

PubMed2002

Transforming growth factor-beta1 suppresses atopic dermatitis-like skin lesions in NC/Nga mice.

BACKGROUND: Atopic dermatitis is a chronic, relapsing inflammatory disorder characterized by pruritic and eczematous skin lesions. Transforming growth factor (TGF)-beta1 has been implicated in the suppression of inflammatory responses. OBJECTIVE: The purpose of this study is to determine whether TGF-beta1 suppresses skin lesions in a mouse model of atopic dermatitis. METHODS: We used the NC/Nga strain of mice as an in vivo model of atopic dermatitis. The effects of exogenous TGF-beta1 on atopic dermatitis-like skin lesions in NC/Nga mice were evaluated clinically, histologically and immunologically. RESULTS: Subcutaneous injection of recombinant TGF-beta1 macroscopically suppressed eczematous skin lesions in NC/Nga mice associated with reduced serum immunoglobulin E (IgE) levels. Histological analysis showed that TGF-beta1 significantly inhibited the infiltration of inflammatory cells such as mast cells and eosinophils into the skin of NC/Nga mice. Spontaneous interferon (IFN)-gamma production from splenocytes of NC/Nga mice was down-regulated by the treatment with TGF-beta1 and neutralizing antibody against IFN-gamma inhibited skin lesions in NC/Nga mice. The inhibitory effect of TGF-beta1 on the skin lesions lasted at least 1 week after cessation of the treatment. CONCLUSION: These findings indicate that TGF-beta1 suppressed atopic dermatitis-like skin lesions in NC/Nga mice at least in part through down-regulation of IFN-gamma. These results suggest that TGF-beta1 may have a therapeutic potential for atopic dermatitis.

Animals↗

PubMed2002

Pressure-pain threshold determination in the oral mucosa: validity and reliability.

Fundamental knowledge of pain in the oral mucosa is lacking. We determined the validity and reliability of the pressure-pain threshold (PPT) measurement in the oral mucosa using a newly developed hand-held pressure algometer. Ten dentulous subjects were recruited, and the PPT was measured at the bilateral buccal (on the attached gingiva apical to the midline of the upper first premolars, 3 mm from the mucogingival junction) and the palatal sites (mid-point between the bilateral upper first molars). The PPT linearly increased with an increase in load-rate (P < 0.0001). The PPT yielded a high intra-individual stability both for the same-day consecutive trials and weekly sessions. The palatal site revealed a 4- to 4.65-fold greater PPT than the buccal sites (Bonferroni, P < 0.0001), whereas no difference was found between the bilateral buccal sites (P=0.663). Despite a great interindividual variation in the PPT, significant intra-individual correlations were found among the measurement sites. This suggested differences in individual sensitivity to pain in the oral mucosa, which may determine overall pain sensation specific to an individual. A pressure algometer described herein reliably assessed the PPT in the oral mucosa and sensitively discriminated PPT differences at different sites and at different load-rates, suggesting the reliability and validity of PPT measurements in the oral mucosa for clinical and research investigations.

Adult↗

PubMed2000

Cerebral blood flow measurement of severely head-injured patients during mild hypothermia.

In 14 patients with severe head injury, the cerebral blood flow (CBF) during mild hypothermia therapy was measured. Their Glasgow Coma Scale scores on admission were 8 or less and the intracranial pressures were greater than 20 mmHg despite conventional therapy. The CBF was measured with two-level stable xenon CT techniques. And in 11 patients, the cerebral metabolic rates for oxygen (CMRO2) was also calculated. All cases were divided into two groups according to the outcome at discharge by using the Glasgow Outcome Scale, good outcome group in 6 and poor outcome one in 8. The values of mean CBF and CMRO2 of each group were 25.6 +/- 6.6 vs 24.4 +/- 6.4 ml/100 g/min and 1.26 +/- 0.45 vs 0.79 +/- 0.31 ml/100 g/ml, respectively. There were no statistically significant differences between both groups. Single CBF measurement during this therapy may not be helpful as a factor of prognosis evaluation in patients with severe head injury.

Adolescent↗

PubMed1999

Pancreatic Schwannoma: report of a case.

We present herein a case of solitary schwannoma of the pancreas and also review 26 previously reported cases from the English and Japanese literature. Primary schwannoma of the pancreas is a rare tumor. A 50-year-old female was discovered to have a large mass in the upper abdomen on ultrasonography. An examination by computed tomography (CT) scan, magnetic resonance imaging (MRI), and ultrasonography revealed a solid and cystic tumor in the left upper quadrant of the abdomen. A distal pancreatectomy with a splenectomy was performed to remove this tumor. A microscopic examination identified the tumor to be situated in the pancreas while it was composed of cells that originated from Schwann cells. Only 26 cases of pancreatic schwannoma have previously been reported in the English and Japanese literature. We describe in detail the characteristic findings based on image analyses, including CT scan, MRI, ultrasonography, and angiography, in these 26 cases.

Diagnostic Imaging↗

PubMed1999

[Arterial infusion therapy with implantable port for inoperable hepatobiliary tumors].

PURPOSE: To assess the clinical utility of arterial infusion therapy with implantable port for inoperable malignant hepatobiliary tumors. MATERIALS AND METHODS: Twenty-seven patients with advanced hepatobiliary tumors (M:F = 14:13, mean age 63.6, 11 cases with metastases from colon cancer, 4 cases from gastric cancer, 5 cases with gallbladder cancer, 3 cases with cholangiocarcinoma, 2 cases with cholangiocellularcarcinoma, 1 case with hepatocellular carcinoma and 1 with pancreatic cancer) were treated with arterial infusion ports which were placed via left subclavian artery or femoral artery. The regimens used were FEM for 5 cases, EEP for 2 cases and FP for 20 cases. RESULTS: Overall mean survival date was 241.8 days. The numbers of cases with CR, PR, NC and PD were 1, 6, 10 and 10, respectively, and the effective rate was 25.9%. Mean survivals of cases with cholangiocellularcarcinoma, metastases from gastric cancer and colon cancer were 715 days, 324.3 days and 245.9 days, respectively. Severe gastrointestinal side effects (> grade 3) were not observed. Serious bone marrow suppressions were frequently observed with FEM and EEP, but were rare with FP (10%). DISCUSSION: Arterial infusion therapy with implantable port is clinically useful for advanced cholangiocancer and metastases from the gastrointestinal system. This system contributes to the quality of life of patients, since the infusion procedure is simple and can be archived in the outpatient clinics.

Adult↗

PubMed1998

Difference in the mechanism of balancing-side disclusion between 1st and 2nd molars.

This study investigates the cusp angle and movement variables related to balancing-side disclusion and compares the characteristics between the 1st and 2nd molar regions. Fifty-six normal young adults were divided into two groups according to balancing-side contact: a disclusion group consisting of 40 subjects (80 excursions), and a non-disclusion group consisting of 16 subjects (20 excursions). Lateral excursions were measured in six-degrees of freedom, and the inclinations of the frontal paths were calculated on the working-side canine, balancing-side 1st and 2nd molars and balancing-side condylar point. The cusp angle was measured using a three-dimensional digitizer. While there were no differences between disclusion and non-disclusion groups in the inclination of the balancing-side condylar path, significant differences were found in the cusp angle and the inclination of the working-side canine path. In the non-disclusion group, the cusp angle of the 2nd molar was markedly greater than that of the 1st molar. It was concluded that the inclination of the anterior guidance and the cusp angle of related teeth have a great effect on the occurrence of balancing-side disclusion and that the mechanism of high frequent balancing-side contacts at the 2nd molar was characterized by its greater cusp angle compared to the 1st molar.

Adult↗

PubMed1998

Relationship between preoperative assessment of organ function and postoperative morbidity in patients with oesophageal cancer.

OBJECTIVE: To find out if strict assessment of organ function preoperatively predicted morbidity and mortality in patients being operated on for oesophageal carcinoma. DESIGN: Retrospective study. SETTING: Teaching hospital, Japan. SUBJECTS: 178 patients operated on for oesophageal cancer 1989-1993. INTERVENTIONS: Oesophagectomy and reconstruction (using either stomach or colon) in one stage by a right thoracoabdominal approach in 173, and transhiatal resection in 5 with either poor pulmonary reserve or early lesions. MAIN OUTCOME MEASURES: Correlation between preoperative assessment of organ function and postoperative development of complications. RESULT: 79 patients (44%) developed complications and 6 died (3%). Pulmonary dysfunction preoperatively was significantly associated with the development of all complications (p=0.001) and of postoperative pulmonary complications (p=0.04). No other preoperative assessment correlated significantly with the development of postoperative complications. CONCLUSION: Accurate preoperative assessment of pulmonary function is a valuable indicator of postoperative morbidity.

Aged↗

PubMed1998

Adenosquamous carcinoma of the pancreas: report of two cases.

Adenosquamous carcinoma of the pancreas is a rare variant of pancreatic exocrine carcinoma. We herein report two patients with this entity. One patient was a 60-yr-old Japanese man complaining of a palpable mass, 5.5 cm in the greatest diameter, in the epigastrium. Serum CA 19-9 was increased (2010 U/ml). Ultrasonography and computed tomography showed a mass in the pancreatic tail with central necrosis and invading the posterior wall of the stomach. Angiography showed an encasement of the splenic artery and complete obstruction of the splenic vein. Distal pancreatectomy, splenectomy, and partial resection of the stomach were done. The patient died of uncontrolled bleeding from the duodenal ulcer four months after operation. The other patient was a 73-yr-old man who presented with jaundice. The CA 19-9 was also elevated (354.8 U/ml). Ultrasonography showed a pancreatic head mass of heterogeneous echogeneity and computed tomography demonstrated a cystic mass with an enhanced rim, indicating necrosis in the tumor center. Angiography showed a hypervascular mass in the head of the pancreas. Pylorus-preserving pancreatoduodenectomy was done, but the patient died of multiple liver metastases 10 months after the operation. From our experience with the two patients, the presence of central necrosis in an infiltrative huge pancreatic tumor seems to be suggestive of the diagnosis of adenosquamous carcinoma of the pancreas.

Aged↗

PubMed1997

Tumor invasion and angiogenesis in early esophageal squamous cell carcinoma.

BACKGROUND AND OBJECTIVES: Although the relationship between angiogenesis and tumor proliferation or malignant potential has been previously demonstrated in several studies, early stage of cancer invasion and angiogenesis has seldom been investigated. METHODS: From the esophageal specimens of eight recently resected cases with esophageal squamous cell carcinoma, 25 areas of carcinoma-in-situ or microinvasive carcinoma were selected, and then a serial histologic investigation and immunohistochemical staining for the detection of Factor VIII-related antigen to investigate microvessels in the lamina propria mucosae beneath the lesions as a measure of angiogeneses and staining for laminin to visualize basement membrane was performed. Lymphocyte infiltration below the lesions were also estimated. In view of early cancerous invasion, histologic patterns of the growth of the lesions were divided into "flat," "expansive," and "downgrowth" patterns. RESULTS: Although downgrowth patterns are thought to be more invasive, relationships between the histologic patterns, and basement membrane staining patterns, and lymphocyte infiltration patterns were not demonstrated. However, the angiogenetic ratio (the number of vessels/cm under the lesions divided by that under normal epithelium) was observed to be significantly and closely related to tumor invasion patterns (P < 0.01), although it was not related to the destruction of the basement membrane or lymphocyte infiltration below the lesions. CONCLUSIONS: The angiogenesis of esophageal squamous cell carcinoma is closely correlated to the tumor invasion patterns in early esophageal cancerous lesions.

Carcinoma in Situ↗

PubMed1997

Biosynthesis and secretion of MHC class III gene products (complement C4 and factor B) in the exocrine pancreas.

We recently found that complement C3 is locally synthesized and secreted into the exocrine pancreas. In the present study, we attempted to demonstrate the secretion of complement C4 and factor B in the exocrine pancreas. In five samples of pancreatic fluid, both C4 and factor B proteins were detected by enzyme-linked immunosorbent assay (ELISA). Immunoblot analysis revealed the C4 and factor B molecules in pancreatic fluid to be identical with these molecules in serum. Reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis in pancreatic carcinoma cell lines suggested ductal epithelial cells to be the local production sites of these proteins in the pancreas. The secretion of C4 and factor B in ductal cell lines (PANC-1 and MIA PaCa-2) was independently regulated by interleukin (IL)-1 beta, tumor necrosis factor (TNF)-alpha, and interferon (IFN)-gamma; C4 secretion was induced by IFN-gamma, whereas factor B secretion was induced by IL-1 beta, TNF-alpha, or IFN-gamma. These observations indicate that: (a) complement C4 and factor B are secreted into the exocrine pancreas, (b) ductal epithelial cells appear to be the site of C4 and factor B biosynthesis, and (c) local secretion of C4 and factor B in the pancreas is differentially regulated by IL-1 beta, TNF-alpha, and IFN-gamma.

Adult↗

PubMed1997

Characterization of complement C3, C4, and factor B molecules in human bile.

We performed molecular analysis of complement components (C3, C4, and factor B) in human bile by sodium dodecyl sulfate-polyarylamide gel electrophoresis (SDS-PAGE) and immunoblotting. Complement C3 was detected as a molecule composed of a 115-kDa alpha-chain linked to a 70-kDa beta-chain by disulfide bonds, and C3 levels ranged from 45 to 650 micrograms/ml (n = 15). C4 was detected as a triple chain (98-kDa alpha-chain, 73-kDa beta-chain, and 33-kDa gamma-chain) molecule linked by disulfide bonds, and C4 levels ranged from 2.5 to 60 micrograms/ml. Factor B, a component of the alternative pathway, was also detected, as an intact form. Factor B levels ranged from 0.3 to 8.0 micrograms/ml. The sizes and subunit structures of complement components in human bile were compatible with those reported in human serum. The results of a hemolytic assay indicated that complement molecules in human bile were functionally active. These molecules may participate in local immune and inflammatory responses in the biliary tract.

Bile↗

PubMed1997

Effect of occlusal splint on masticatory movement in healthy individuals.

To investigate the effects of wearing an occlusal splint on masticatory movements in healthy individuals, twelve healthy individuals were examined. A full maxillary stabilization splint made of heat-cured acrylic resin was fabricated for, and worn by, each individual for 24 hours. Masticatory movement was measured before and after the 24-hour period using a 3-D mandibular movement analyzing system. While the duration of a masticatory cycle+ did not change, the occlusal time significantly decreased after use of the splint. The lateral displacement of the opening phase to the balancing-side area also decreased after use of the splint, showing a vertical pattern of the opening path. Measurement in more healthy individuals and patients should help clarify the therapeutic mechanism of the splint in the treatment of temporomandibular disorders.

Adult↗

PubMed1997

Tumour necrosis factor-alpha up-regulates decay-accelerating factor gene expression in human intestinal epithelial cells.

The increased expression of decay-accelerating factor (DAF) has been detected in intestinal epithelial cells at the inflamed mucosa. In this study, we examined the effects of tumour necrosis factor (TNF)-alpha on DAF expression in three intestinal epithelial cell lines. DAF mRNA expression was evaluated by Northern blot analysis, and DAF protein expression was analysed by biotin labelling and immunoprecipitation. TNF-alpha induced a marked increase in DAF mRNA and protein expression in HT-29, T84 and Caco-2 cells. In HT-29 cells, the effects of TNF-a on DAF mRNA accumulation were observed in a dose-dependent manner; DAF mRNA accumulation reached a maximum at 3-6 hr, and then gradually decreased. These effects of TNF-alpha required de novo protein synthesis. Messenger RNA stability studies suggested that TNF-alpha partially regulated DAF gene expression by a posttranscriptional mechanism. Moreover, the combination of TNF-alpha and interleukin (IL)-4 induced an additive increase in DAF mRNA accumulation in HT-29 and T84 cells. In human intestinal epithelial cells, TNF-alpha acts as a potent inducer of DAF mRNA expression, indicating an important role for TNF-alpha in the regulation of DAF expression at the inflamed mucosa.

Blotting, Northern↗

PubMed1996

What is the earliest malignant lesion in the esophagus?

BACKGROUND: The incidence of early esophageal cancer is definitely increasing due to recent advances in diagnostics. When we discuss early carcinoma of the esophagus, however, there is still controversy as to whether dysplasia is either benign or the earliest malignant lesion. METHODS: Nineteen resected esophaguses with both cancer and dysplasia (including 19 cancers concomitant with 26 dysplastic lesions) were studied for expression of p53 protein. RESULTS: Immunohistochemical overexpression of p53 protein in esophageal dysplasia is almost the same as that in cancer. CONCLUSIONS: Esophageal dysplasia should be recognized as the earliest malignant lesion which already demonstrates cancerous features although it is not immediately critical. A routine endoscopic Lugol's solution test is very useful for both detection and following-up of the early nests in the esophagus. These lesions are good candidates for endoscopic mucosal resection for the purpose of accurate diagnosis or curative treatment.

Esophageal Neoplasms↗