Biomedical subjects

H Kato

Publications and source records attributed to H Kato.

At least 37 records · Page 2Linked to original sources

PubMed2005

A large inflammatory fibroid polyp of the colon treated by endoclip-assisted endoscopic polypectomy: A case report.

Inflammatory fibroid polyp is a rare benign polypoid lesion of the gastrointestinal tract. Histologically, inflammatory fibroid polyp is characterised by an admixture of numerous small vessels, fibroblasts and oedematous connective tissue, accompanied by marked inflammatory infiltration by eosinophils. A 40-year-old man visited our hospital for the purpose of colorectal screening due to a positive faecal occult blood test. A pedunculated and reddish polyp was found endoscopically in the ascending colon. The polyp was large but was resected endoscopically without any problems. Histologically, the abnormal tissue of the polyp was located in the submucosal and mucosal layer. Proliferation of spindle cells and infiltration of inflammatory cells, such as plasma cells and eosinophils, were observed. Immunohistochemically, the spindle cells were positive for CD34, which was localised in the cytoplasm. These cells were also positive for S100 protein but were negative for c-kit and muscle markers. These findings are compatible with the histological diagnosis of inflammatory fibroid polyp. The surgical margin of the polyp was free of the tumour. Inflammatory fibroid polyp is more commonly found in the stomach or small intestine, and rarely in the colon, and therefore our case is a rare example of large and pedunculated colonic inflammatory fibroid polyp, which was treated successfully by endoscopic polypectomy.

Adult↗

PubMed2005

Phase I trial of oral S-1 combined with gemcitabine in metastatic pancreatic cancer.

The objective of this study was to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of S-1, an oral fluorouracil derivative, combined with gemcitabine, the current standard treatment for advanced pancreatic cancer (APC). The subjects were histopathologically proven APC patients with distant metastasis. S-1 was administered orally twice daily each day for 14 days and gemcitabine on days 8 and 15 of each cycle, and this was repeated every 21 days. Doses of each drug were planned as follows: level 1: 800/60, level 2a: 800/80, level 2b: 1000/60, level 3: 1000/80 (gemcitabine (mg m(-2))/S-1 (mg m(-2) day(-1))). In all, 21 patients with APC were enrolled. The main grade 3-4 toxicities observed during first cycle were neutropenia (33%), anaemia (10%), thrombocytopenia (14%) and anorexia (10%). There were no DLT observed in level 1. Three of six patients in level 2a had DLT and this level was considered the MTD. In all, 12 patients in level 2b had no DLT and this level was selected as the recommended dose. Applicable responses were one complete response and nine partial responses (48%). As toxicities were well tolerated and antitumour activities seem to be promising, this combination can be recommended for further phase II studies with APC.

Administration, Oral↗

PubMed2005

Synthetic biodegradable polymers as drug delivery systems for bone morphogenetic proteins.

Bone morphogenetic proteins (BMP) induce bone formation in vivo, and clinical application in repair of bone fractures and defects is expected. However, appropriate systems to deliver BMP for clinical use need to be developed. We synthesized a new synthetic biodegradable polymer, poly-D,L-lactic acid-para-dioxanone-polyethylene glycol block copolymer (PLA-DX-PEG), to serve as a biocompatible, biodegradable polymer for recombinant human (rh) BMP-2 delivery systems. In animal experiments, new bone was efficiently formed and a large bone defect was repaired using PLA-DX-PEG/rhBMP-2 composites. In addition, this new polymer could be used as an injectable delivery system for rhBMP-2. The rhBMP-2/PLA-DX-PEG composites also could be combined with other materials such as hydroxyapatite or titanium. This new synthetic polymer might be used for rhBMP-2 delivery in various clinical situations involving repair of bone, leading to great changes in orthopedic treatment.

Animals↗

PubMed2005

Spatially dependent inelastic tunneling in a single metallofullerene.

We have measured the elastic and inelastic tunneling properties of isolated Gd@C(82) molecules on Ag(001) using cryogenic scanning tunneling spectroscopy. We find that the dominant inelastic channel is spatially well localized to a particular region of the molecule. Ab initio pseudopotential density-functional theory calculations indicate that this channel arises from a vibrational cage mode. We further show that the observed inelastic tunneling localization is explained by strong localization in the molecular electron-phonon coupling to this mode.

Journal Article↗

PubMed2005

Individual fundamental mode dependence of H2O vibrational excitation in the 6-8 eV resonance region by electron impact.

Resonance phenomena in the bending (010), symmetric (100), and asymmetric (001) stretching vibrational modes in water (H(2)O) molecules have been investigated by measuring differential cross sections (DCSs) at fixed energy losses of 0.43, 0.46, 0.49, and 0.51 eV while sweeping the impact energies from 1.6 to 10 eV, at angles 60 degrees and 90 degrees, using a crossed-beam method. No resonancelike enhanced features have been observed in the study of the (010) mode. In the DCSs for the combined (100+001) mode, a single broad hump was observed at each angle, whose position shifts towards the higher energy side with increasing scattering angle, a feature typical of the interference profiles previously observed in a study of the (301) vibrational mode. DCSs for the (001) mode exhibited a rather isotropic angular distribution with no evidence of resonances. However, enhancement of DCSs were indeed observed for the (100) mode, at the energy loss of 0.46 eV, which is attributable to the A(1) symmetry resonance that was studied by Seng and Linder [J. Phys. B 9, 2539 (1976)], with a typical s-wave characteristic angular distribution. Theoretical analysis based on the continuum multiple-scattering approach has been carried out to provide rationale to the experimental results.

Journal Article↗

PubMed2005

Surgery for clinical T3 carcinomas of the upper thoracic oesophagus and the need for new strategies.

BACKGROUND: Patients with T3 carcinomas have a dismal prognosis, even after complete resection of the primary tumour and metastatic nodes. This study focused on the clinicopathological characteristics and outcomes after surgical resection of clinical T3 carcinomas of the upper thoracic oesophagus. METHODS: Between January 1988 and February 2000, 888 consecutive patients underwent surgical removal of carcinomas of the thoracic oesophagus or oesophagogastric junction at the National Cancer Centre Hospital, Japan. The case records of 51 consecutive patients with clinical T3 tumours of the upper thoracic oesophagus were analysed retrospectively. RESULTS: No patient received preoperative therapy. Complications occurred in 41 (80 per cent). In-hospital and 30-day postoperative mortality rates were 10 and 4 per cent respectively. Gross residual primary tumour or metastasis in regional nodes invading adjacent structures was noted in 14 patients (27 per cent) and incomplete resection including microscopic residual tumour in 23 (45 per cent). Overall 3- and 5-year survival rates were 20 and 12 per cent; median survival was 13.1 months. CONCLUSION: Surgical resection of clinical T3 carcinomas of the upper thoracic oesophagus is associated with a high postoperative complication rate, incomplete resection and unsatisfactory outcome. Reconsideration of the surgical treatment strategy for these tumours is needed.

Adult↗

PubMed2005

Correlation between RhoA overexpression and tumour progression in esophageal squamous cell carcinoma.

AIMS: The aim of this study was to clarify the clinico-pathologic outcome and prognostic significance of RhoA in esophageal squamous cell carcinoma (ESCC). METHODS: Immunohistochemical staining for RhoA was performed on surgical specimens obtained from 122 patients with ESCC. RESULTS: There were significant correlations among RhoA overexpression and TNM clinical classification (depth of invasion, P=0.028; presence of regional lymph node metastasis, P=0.009; presence of distant metastasis, P=0.003; staging P=0.006), lymphatic invasion (P=0.002), and blood-vessel invasion (P=0.004). The five-year survival rates for ESCC patients with RhoA overexpression were significantly lower than those in patients with RhoA under-expression (P=0.002). CONCLUSIONS: Our results demonstrated immunohistochemically that the expression of RhoA protein appeared to be correlated with tumour progression of ESCC. Patients with RhoA overexpression tended to have poor prognosis compared with patients with RhoA under-expression.

Adult↗

PubMed2005

Direct evidence for mutual interactions between perineuronal astrocytes and interneurons in the CA1 region of the rat hippocampus.

Recent studies have demonstrated that astrocytes express a variety of ion channels and neurotransmitter receptors and can modulate the activity of neurons. Since a single astrocyte makes tight contacts with many neighboring neuronal cells, they can provide efficient and wide modulation of neuronal networks. Here, we provide direct evidence for mutual interactions between perineuronal astrocytes and interneurons in the stratum radiatum of the rat hippocampus. Direct depolarization of a perineuronal astrocyte suppressed the excitatory postsynaptic currents in an adjacent interneuron and increased the paired-pulse ratio, indicating that perineuronal astrocytes have a suppressive effect on presynaptic elements. Moreover, perineuronal astrocyte activation modulated the directly induced firing pattern of the interneuron, with initial facilitation and subsequent suppression. Conversely, direct firing of the interneuron depolarized the membrane potential and reduced the input resistance of the perineuronal astrocyte. These results directly demonstrate the existence of bidirectional interactions between neurons and perineuronal astrocytes.

4-Aminopyridine↗

PubMed2005

Infected Charcot spine.

STUDY DESIGN: Case report of an infected Charcot spine following spinal cord injury. OBJECTIVE: To describe this very rare pathological condition and the results of surgical treatment. SETTING: A department of orthopaedic surgery in Japan. METHODS: A 44-year-old man presented with a destructive lesion in the lumbo-sacral spine and a fistula in his back. Anterior bone graft, percutaneous external spinal fixation, and suction/irrigation of the wound were performed. After 4 months, posterior spinal instrumentation surgery was carried out. RESULTS: Primary closure of the fistula and complete bone fusion was achieved after the operation. CONCLUSION: Infection of a Charcot spine, although a rare clinical entity, should be considered as a diagnostic possibility in the spinal cord-injured patients. External spinal fixation is a useful method for the unstable spinal lesion with infection.

Adult↗

PubMed2005

Predominant presence of Streptococcus anginosus in the saliva of alcoholics.

Chronic alcohol consumption is known to be a major risk factor for cancers of the upper aerodigestive tract. The incidence of esophageal cancer (4.4%) in alcoholics is reported to be much higher than that in the Japanese population as a whole (0.0001%). This suggests the presence of specific factors in chronic alcohol consumption-related carcinogenesis. Recently, data showing a significant correlation between Streptococcus anginosus and carcinogenesis in the upper aerodigestive tract have been reported. In this study, the ratio of S. anginosus to oral bacteria in the saliva of 38 alcoholic patients was investigated to determine if there is an association between alcoholic patients and S. anginosus infection. The level of S. anginosus in the saliva from 22 healthy people, 41 esophageal cancer patients, 32 gastritis patients, and 24 periodontitis patients was also investigated and compared to the level in alcoholic patients. In the saliva from esophageal cancer patients, the level of S. anginosus was not significantly different from that of healthy people. The levels of S. anginosus in periodontitis and gastritis patients were also similar. In alcoholics, however, there was an extremely high level of S. anginosus, suggesting that they, rather than healthy people and general esophageal cancer patients, have a high risk for S. anginosus infection.

Adult↗

PubMed2005

RASSF1A gene promoter methylation in esophageal cancer specimens.

SUMMARY. RASSF1A is frequently inactivated by promoter methylation in human cancers. To understand the involvement of the RASSF1A gene in esophageal squamous cell cancer (ESCC), we investigated the methylation of the RASSF1A gene in primary ESCC to define the frequency of this epigenetic aberration and its clinicopathological significance. Methylation-specific polymerase chain reaction (MSP) was used to detect RASSF1A gene methylation in DNA from 55 cases of ESCC. Methylation of the RASSF1A gene was found in 13 of 55 (24%) cases of primary ESCC. No association was found between the promoter methylation of the RASSF1A gene in primary ESCC and age, gender, localization, invasion depth, or tumor stage. Association was found with tumor differentiation. There was no correlation with its prognosis. In conclusion, it was suggested that an inactivation of the RASSF1A gene due to promoter methylation was associated with de-differentiation of the tumor in ESCC.

Age Factors↗

PubMed2005

Expression and subcellular localization of WAVE isoforms in the megakaryocyte/platelet lineage.

WAVE isoforms, which consist of WAVE-1, WAVE-2 and WAVE-3, are members of the Wiskott-Aldrich syndrome protein (WASP) family. They are implicated in the regulation of actin-cytoskeletal reorganization downsteam of the small GTPase, Rac. Since platelet attachment to extracellular matrices leads to filopodial and lamellipodial extension, we examined the expression and subcellular localization of WAVEs in platelets. Employing primary megakaryocytic cells derived from cord blood as well as megakaryocytic cell lines, we also examined their expression during megakaryocytic differentiation. Immunoblotting and immunohistochemical analysis revealed that platelets expressed WAVE-1 and WAVE-2, whereas WAVE-3 expression was hardly to be detected. WAVE-1 expression was associated with megakaryocytic differentiation, whereas WAVE-2 and WAVE-3 expression was not changed by the differentiation. In adhered platelets both WAVE-1 and WAVE-2 were localized at the edge of the lamellipodia and at the tips of filopodia. In WASP-deficient platelets we found normal lamellipodial formation and localization of WAVE-1 and WAVE-2 at the edges of lamellipodia. Furthermore, we demonstrated that WAVE-1 and WAVE-2 moved from a detergent-soluble cytosolic fraction to insoluble cytoskeleton fraction after platelet aggregation. These results suggest that WAVE-1 and WAVE-2 regulate actin reorganization during platelet spreading and aggregate formation.

Blood Platelets↗

PubMed2005

Impaired platelet function in a patient with P2Y12 deficiency caused by a mutation in the translation initiation codon.

In this study, we have identified a patient (OSP-1) with a congenital P2Y12 deficiency showing a mild bleeding tendency from her childhood and examined the role of P2Y12 in platelet function. At low concentrations of agonists OSP-1 platelets showed an impaired aggregation to several kinds of stimuli, whereas at high concentrations they showed a specifically impaired platelet aggregation to adenosine diphosphate (ADP). ADP normally induced platelet shape change and failed to inhibit PGE1-stimulated cAMP accumulation in OSP-1 platelets. Molecular genetic analysis revealed that OSP-1 was a homozygous for a mutation in the translation initiation codon (ATG to AGG) in the P2Y12 gene. Heterologous cell expression of wild-type or mutant P2Y12 confirmed that the mutation was responsible for the deficiency in P2Y12. OSP-1 platelets showed a markedly impaired platelet spreading onto immobilized fibrinogen. Real-time observations of thrombogenesis under a high shear rate (2000 s(-1)) revealed that thrombi over collagen were small and loosely packed and most of the aggregates were unable to resist against high shear stress in OSP-1. Our data suggest that secretion of endogenous ADP and subsequent P2Y12-mediated signaling are critical for platelet aggregation, platelet spreading, and as a consequence, for stabilization of thrombus.

Aged↗

PubMed2005

Formation and resolution of ankylosis under application of recombinant human bone morphogenetic protein-2 (rhBMP-2) to class III furcation defects in cats.

OBJECTIVES: Periodontal regeneration under application of bone morphogenetic protein (BMP) is compromised by ankylosis. Ankylosis disappearance following application of BMP has been observed in the case of a small defect, which might be beneficial change for periodontal regeneration. However, the histological observation of ankylosis disappearance has not been demonstrated in a large defect. The purpose of this present study was to confirm resolution of ankylosis during periodontal regeneration by recombinant human BMP-2 (rhBMP-2) applied to class III furcation defects. MATERIAL AND METHODS: Class III furcation defects were created in the premolars of six adult cats. The rhBMP-2 material, prepared by applying rhBMP-2 to a combination of polylactic acid-polygricolic copolymer and gelatin sponge (PGS; 0.33 microg rhBMP-2/mm(3) PGS) or control material containing only PGS, was implanted into each defect. The cats were killed at 3, 6 or 12 weeks after surgery and serial sections were prepared for histological and histometrical observation. RESULTS: Ankylosis was observed in some of the rhBMP-2/PGS group at 3 and 6 weeks, but not at 12 weeks. At 6 weeks, osteoclast-like cells were visible in the rhBMP-2/PGS group with ankylosis. Residual PGS was evident between the bone and root surface in the rhBMP-2/PGS group without ankylosis at 3 weeks. CONCLUSIONS: Resolution of ankylosis by osteoclast-like cells possibly occurred under application of rhBMP-2. Residual PGS might play an important role in preventing ankylosis formation.

Absorbable Implants↗

PubMed2005

Quantitative detection of volatile sulfur compound- producing microorganisms in oral specimens using real-time PCR.

OBJECTIVE: It is well-known that some periodontopathic bacteria, especially Porphyromonas gingivalis, Fusobacterium nucleatum, Tannerella forsythia (formerly Bacteroides forsythus or Tan. forsythensis), and Treponema denticola, actively produce volatile sulfur compounds (VSCs), such as H2S and CH3SH. We previously reported a qualitative relationship between periodontopathic bacteria and VSCs; however, a quantitative analysis of periodontopathic bacteria in oral specimens is required for further characterization of the relationship between oral bacteria and VSCs. In this study, we report a real-time polymerase chain reaction (PCR) method for the quantitative analysis of VSC-producing bacteria in oral specimens. SUBJECTS AND METHODS: Specimens were collected from 22 patients who visited the Preventive Dentistry and Breath Odor Clinic of Kyushu Dental College. A real-time PCR assay using the TaqMan system, based on the 5'-3' exonuclease activity of Taq polymerase, was employed for the quantitative analysis of periodontopathic bacteria that produce VSCs. RESULTS: Using real-time PCR, we performed a quantitative analysis of P. gingivalis, F. nucleatum, Tan. forsythia, and T. denticola in the saliva, on the tongue coat, and in the subgingival plaque of patients with oral malodor. CONCLUSION: Real-time PCR using the TaqMan system can be used for the quantitative analysis of VSC-producing oral bacteria.

Adult↗

PubMed2005

Clinical course of fetal congenital atrioventricular block in the Japanese population: a multicentre experience.

OBJECTIVES: To elucidate the prenatal and postnatal course of fetal congenital atrioventricular block (CAVB) during the past decade in the Japanese population. DESIGN: Retrospective multicentre study. All fetuses with CAVB in 10 Japanese institutions in the period from January 1990 to August 2001 were included. PATIENTS: Of the 48 fetuses with CAVB, 17 had a congenital heart defect (CHD) (14 with left atrial isomerism) and 31 had a structurally normal heart (22 with positive maternal autoantibodies). Gestational age at diagnosis was 15 to 38 (median 26) weeks. RESULTS: Of the 17 fetuses with a CHD, three were aborted, one died before birth, and eight died after birth (three in the neonatal period and five after the neonatal period). Of the 31 fetuses without a CHD, two died before birth and two died after birth. CHD (p = 0.005) and the presence of fetal hydrops (p = 0.05) were significant risk factors for death. However, fetal ventricular and atrial heart rates, gestational age at delivery, and birth weight were not related to death. Transplacental medication of sympathomimetics increased the fetal heart rate in five of eight fetuses treated. Dexamethasone did not improve the degree of heart block in any of the six fetuses treated. Postnatally, pacemakers were implanted in 30 of 40 babies. Four fetuses with maternal autoantibodies had decreased cardiac function. CONCLUSIONS: CHD and fetal hydrops are risk factors for prenatal and postnatal death. The fetal ventricular rate of 55 beats/min did not appear to be a threshold value by which to predict fetal hydrops. Patients with CAVB should be subjected to close long term follow up to check for the need for pacemaker implantation or for late onset cardiac dysfunction.

Anti-Arrhythmia Agents↗

PubMed2005

Quantitative MRI of the wrist and nerve conduction studies in patients with idiopathic carpal tunnel syndrome.

OBJECTIVE: To correlate morphological findings of idiopathic carpal tunnel syndrome (CTS) with the function of the median nerve. METHODS: In this study, 105 wrists of 105 women patients with idiopathic CTS, and 36 wrists of 36 female volunteers were subjected to nerve conduction studies and MRI. Cross sectional area, signal intensity ratio, and the flattening ratio of the median nerve, carpal tunnel area, flexor tendon area, synovial area, and intersynovial space, and the palmar bowing of the transverse carpal ligament (TCL) were quantified by MRI and correlated with the severity of the disease determined by nerve conduction studies. RESULTS: Cross sectional areas of the median nerve, flexor tendons, and carpal tunnel, and the palmar bowing of the TCL of the CTS groups were greater than in the control group, but differences were not detected among the CTS groups for the area of the flexor tendons and the carpal tunnel. Enlargement, flattening, and high signal intensity of the median nerve at the distal radioulnar joint level were more significant in the advanced than in the earlier stages of the disease. Increase in palmar bowing of the TCL was less prominent in the most advanced group. Linear correlation between the area of the carpal tunnel and palmar bowing of the TCL was noted. CONCLUSION: Severity of the disease could be judged by evaluating not only longitudinal changes of signal intensity and configuration of the median nerve, but also palmar bowing of the TCL. Increased palmar bowing of the TCL was found to be associated with an increase in the area of the carpal tunnel.

Carpal Tunnel Syndrome↗

PubMed2005

[Pneumothorax in elderly patients].

Pneumothorax is a frequent affliction with the incidence peaks in youth and old age. The disease is more frequent in males and smokers. Most of the old patients have emphysema and/ or pulmonary fibrosis as the underlying disease. They often show low respiratory function and/ or heart failure. The first step in treatment is pleural drainage to achieve pulmonary re-expansion. If it is difficult to cure by pleural drainage, we try to perform pleurodesis using the chemicals such as OK-432 and tetracycline. As the next step, we try to perform video assisted thoracic surgery (VATS) or operation without video. To stop smoking is important before and after operation. We reviewed about pneumothorax in old patients.

Aged↗