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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 73 records · Page 4Linked to original sources

[Anesthetic management of a patient with tetanus using epidural anesthesia].

A 75-year-old woman with breast cancer complicated with tetanus was scheduled for mastectomy. Since severe bradycardia (17 beats.min-1) was detected by preoperative Holter monitoring, a temporary pacing catheter was inserted. She underwent mastectomy under general anesthesia using propofol combined with thoracic epidural anesthesia. She also received postoperative thoracic epidural block. Her perioperative heart rate was 80-105 beats.min-1 and the rhythm was sinus. There was no marked perioperative cardiovascular derangement.

Aged↗

[Endoscopic mucosal resection for early gastric carcinoma].

Endoscopic mucosal resection (EMR) has made it possible to perform radical resection of early gastric cancers in resectable cases. To extend the indications for EMR, we discuss the following. 1) Three hundred fifty-seven patients with 389 lesions of early gastric cancer who were treated either with whole-block resection or partial resection were analyzed to evaluate the recurrence rate by the method. The recurrence rate was 15.1% of 139 lesions treated with whole-block resection and 8.0% of 250 lesions treated with both methods. It is considered that partial resection with the marking procedure is very important to remove the cancer completely. 2) The management of recurrent cancer recognized at follow-up examination after EMR is very important for patients because these are operable cases. Of recurrent cancers, 80.5% were diagnosed within one year after EMR, and therefore during this period careful follow-up examinations should be done. The therapy used to treat these recurrent cancers was re-EMR in 26 cases and surgical operation in 15 cases. 3) Problems still remain concerning how to manage cancer invading the submucosa diagnosed after EMR.

Endoscopy, Gastrointestinal↗

Two-dimensional changes in soft tissue profile following surgical mandibular advancement in Japanese retrognathic adults.

The purpose of this study was to evaluate changes in the hard and soft tissues and to test a preliminary method for predicting the soft tissue profile changes in 14 Japanese retrognathic patients who underwent surgical mandibular advancement. A pair of pre- and postoperative lateral cephalograms was taken for each subject. A paired t test identified significant hard and soft tissue changes following surgery. A Pearson correlation analysis was used to identify soft tissue changes for hard tissue changes in the horizontal and vertical dimensions. Multiple regression models were generated to predict postoperative variables based on preoperative variables. Significant changes in the hard and soft tissues were found in the area inferior to the point Stomion in both the horizontal and vertical dimensions. The soft tissue changes demonstrated a significant correlation not only with the corresponding hard tissue, but also with noncorresponding anatomical points. Moreover, the tendency of changes in the soft tissue was different in the lower lip area from the chin area in both the horizontal and vertical dimensions. Significant R2 and higher contribution ratio were obtained from the multiple regression analysis for the chin area compared to the lower lip area.

Adult↗

Effects of sildenafil citrate (Viagra) combined with nitrate on the heart.

BACKGROUND: Sildenafil citrate (Viagra) is indicated for the treatment of erectile dysfunction. Large and sudden decreases in systemic blood pressure were reported in a substantial number of patients taking sildenafil citrate combined with nitroglycerin. We studied the effect of sildenafil citrate on the relationship between changes in systemic blood pressure and coronary blood flow. METHODS AND RESULTS: Healthy male beagles were used to assess systemic blood pressure, pulmonary arterial pressure, and flow in the left circumflex artery (in which a critical stenosis was established) and left anterior descending coronary artery. After measurement of the hemodynamic variables, 2 mg/kg sildenafil citrate was administered via a nasogastric tube. Hemodynamic changes were monitored for 1 hour. Subsequently, the acute effect of nitrate combined with sildenafil citrate was studied by the bolus injection of 0.2 mg isosorbide dinitrate before and after sildenafil citrate. Systemic blood and pulmonary arterial pressures and circumflex flow did not change during this study; however, left anterior descending coronary arterial flow increased from 16.0+/-5.8 to 24.6+/-8.7 mL/min 1 hour after administration of sildenafil citrate. The prolongation of systemic blood pressure decrease and the circumflex flow decrement induced by isosorbide dinitrate after sildenafil citrate were significantly larger and longer than those before sildenafil citrate. CONCLUSIONS: Sildenafil citrate had the effect of vasodilation in a normal coronary artery; however, a combined effect with nitrate resulted in large and protracted decreases in systemic blood pressure and coronary blood flow in vessels with critical stenosis.

Administration, Oral↗

On-line coupling of solid-phase extraction to gas chromatography with fast solvent vaporization and concentration in an open injector liner. Analysis of pesticides in aqueous samples.

The purpose of this study is to combine solid-phase extraction (SPE) with gas chromatography (GC) for the fully automated determination of pesticides and herbicides in aqueous samples. The interface technique employed for connecting SPE with GC was fast solvent vaporization and concentration in an open injector liner. The interface device consisted of the programmed-temperature vaporizing injector without using the packing material in the liner and the target compounds were concentrated around the inlet of the GC capillary column. This avoided the degradation of target compounds, and no precise control of the injecting speed was required, when an automatic SPE system was connected to GC-MS. The aqueous samples used in this system were prepared by spiking 29 kinds of pesticide and herbicide compounds, which are regulated by the Ministry of Health and Welfare of the Japanese National government, in purified water and river water, to a resulting concentration of 1 microg/l. Employing this system, the recoveries and RSDs (n=6) of most compounds were greater than 75% and within 10%, respectively. From the results of this study, we found that on-line automatic SPE and capillary GC-MS equipped with the fast solvent vaporizing and concentrating method in an open injector liner could be connected in order to obtain good results for the determination of pesticides in water samples.

Chromatography, Gas↗

The role of CD4(+) or CD8(+) T cells in the protective immune response of BALB/c mice to Neospora caninum infection.

The role of CD4(+) or CD8(+) T cells in the immune response of BALB/c mice against Neospora caninum infection was examined by using anti-CD4 and/or anti-CD8 monoclonal antibodies (mAbs). Mice were intraperitoneally inoculated with anti-CD4 and/or anti-CD8 mAbs before and after infection with N. caninum and observed for 30 days after infection. Most of the anti-CD4 mAb-treated mice and all of the anti-CD4 and anti-CD8 mAbs-treated mice died within 30 days post-infection (p.i.). In contrast, 100% of PBS-treated mice and 70% of anti-CD8 mAb-treated mice survived more than 30 days. When compared with phosphate-buffered saline (PBS)-treated mice, the weight of mice treated with mAbs tended to decrease. From these results CD4(+) T cells, but not CD8(+) T cells, have an important role for protection of mice against N. caninum infection. Serum antibody levels to N. caninum in infected-mice treated with anti-CD4 mAb or a mixture of anti-CD4 and anti-CD8 mAbs were lower than those in the infected mice treated with anti-CD8 mAb or PBS. The mice treated with anti-interferon-gamma (IFN-gamma) mAb produced high antibody levels to N. caninum, but all mice died within 18 days p.i. These results indicated that IFN-gamma is an important cytokine for protection against N. caninum infection at the early stage of infection. However, since CD4(+) T cells against N. caninum were essential to the production of specific antibody, these antibodies might have important roles in host protection at the later stage of infection.

Animals↗

A novel gene derived from developing spinal cords, SCDGF, is a unique member of the PDGF/VEGF family.

We isolated a novel gene designated spinal cord-derived growth factor (SCDGF). Its expression was increased in chick spinal cords with embryonic development and decreased after hatching. The amino acid sequences of chick and human SCDGFs revealed a putative signal sequence followed by a CUB domain and a region homologous to the members of the platelet-derived growth factor/vascular endothelial growth factor family. Furthermore, human SCDGF secreted from the cells showed a mitogenic activity for 10T1/2 cells in vitro. These results led us to speculate that SCDGF plays an important role in the development of the spinal cord.

Amino Acid Sequence↗

Switch of histamine receptor expression from H2 to H1 during differentiation of monocytes into macrophages.

It is known that histamine suppresses gene expression and synthesis of tumor necrosis factor alpha (TNF-alpha) induced by lipopolysaccharide (LPS) in human peripheral blood mononuclear monocytes (HPM) or alveolar macrophages via histamine H2 receptors. We investigated the effect of histamine and differentiation in macrophages on the expression and secretion of TNF-alpha, TNF-alpha-converting enzyme (TACE), and histamine H1 and H2 receptors by use of a leukemia cell line, U937, and HPM. Differentiation of U937 and HPM cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) enhanced the H1 receptor expression and rather suppressed the H2 receptor, resulting in up-regulation of the histamine-induced expression and secretion of TNF-alpha, modulated via TACE. Therefore, histamine failed to inhibit up-regulated expression of TNF-alpha induced by LPS in macrophages. The switch from H2 to H1 receptors during differentiation in the monocyte/macrophage lineage could participate in the pathogenic processes of atherosclerosis and inflammatory reactions in the arterial wall.

ADAM Proteins↗

A solitary bone cyst in the spinous process of the cervical spine: a case report.

STUDY DESIGN: A case report. OBJECTIVES: To illustrate a rare case of histologically confirmed solitary bone cyst involving the spinous process of C7. SUMMARY OF BACKGROUND DATA: A solitary bone cyst involving the spine is very unusual. Although four cases of a solitary bone cyst in the spine have been reported in the literature, the current authors have been able to find only one case of solitary bone cyst in the spinous process. All four patients reported in the literature were over 30 years of age. The patient in the current case was a 13-year-old girl with no history of trauma. METHODS: Radiographs and a computed tomography scan of the cervical spine were performed before the operation, as was a histologic examination to make a diagnosis of the lesion. RESULTS: The intraoperative findings from examination of the stagnant fluid within the lesion and the histologic examination indicated the diagnosis of a solitary bone cyst. CONCLUSIONS: A solitary bone cyst in the spine is rare, especially in the young. An osteolytic lesion in the spinous process of the spine tends to be diagnosed as an osteoblastoma or as a giant cell tumor of the bone. A solitary bone cyst of the spine, although rare, must be considered as a differential diagnosis.

Adolescent↗

Detection of mononuclear cells as the source of the increased tissue factor mRNA in the liver from lipopolysaccharide-treated rats.

Tissue factor (TF) triggers the coagulation cascade reaction in vivo. Overexpression of TF mRNA is one leading cause of disseminated intravascular coagulation and thrombosis-related organ failure. In response to lipopolysaccharide (LPS) stimulation, various cell types can produce TF mRNA in vitro. However, there is currently no agreement on what types of cells in the liver overexpress TF mRNA after LPS treatment. For the first report, we found the increased TF mRNA with reverse transcription-polymerase chain reaction (RT-PCR), and confirmed a fourfold increase (p<0.001 vs. control, t-test) of the TF mRNA level with RT-competitive PCR in the liver of LPS-treated (2.0 mg/kg i.v. injection) rats. There was no significant difference in the glyceraldehyde-3-phosphate dehydrogenase mRNA level between LPS-treated rats and control rats. To clarify the localization and cellular source of LPS-induced TF mRNA, we performed in situ hybridization analysis with [35S]-labeled oligonucleotides probes, which we originally designed. We detected intense signals of TF mRNA in mononuclear cells but not in endothelial cells around the hepatic vein of LPS-treated rats. In this study, we showed that the TF mRNA level induced by LPS treatment, which may indicate mononuclear cells associated, significantly increased in the liver of rats. These results will provide circumstantial support for the therapeutic strategy that mononuclear cell should be one of the target cells to be treated in the early phase of disseminated intravascular coagulation in the liver, and that the need to suppress its overexpression of TF mRNA is essential for preventing hypercoagulable condition.

Animals↗

p21 and parathyroid hormone-related peptide in the growth plate.

It is essential for terminal chondrocytes to die before the conversion of calcified cartilage to bone. We have previously demonstrated that apoptosis occurred in the terminal hypertrophic chondrocyte of the growth plate. However, the essential mechanism by which the differentiation of chondrocytes is regulated has not yet been characterized. The purpose of this study was to investigate the mechanism for regulating chondrocyte differentiation. We focused on PTHrP and p21 which regulated the differentiation of chondrocytes and investigated how these factors interacted with each other in chondrocyte differentiation in the growth plate. PTHrP was strongly positive on immunostaining at the interface between the proliferating and the upper zone of the hypertrophic chondrocytes, whereas p21 was negative. On the other hand, p21 was positive in the lower zone of hypertrophic chondrocytes. Furthermore, PTHrP up-regulated the cell proliferation and down-regulated the expression of the p21 messengers in SW-1353 chondrosarcoma cells. These findings indicated that PTHrP might be a negative regulator for p21 in the differentiation of chondrocytes.

Animals↗

Genomic HLA profiles of MS in Hokkaido, Japan: important role of DPB1*0501 allele.

The polymorphism of the HLA class II genes was investigated in 97 patients with multiple sclerosis (MS) in Hokkaido, the northernmost main island of Japan. Of these, 80 patients were classified as having conventional MS and 17 as having opticospinal MS (OS-MS). Our findings confirmed a previous report that the DPB 1*0501 allele is positively associated with OS-MS (P = 0.0043). The frequency of DPB 1*0501 was also found to be higher in conventional MS patients than in controls (79% vs. 58%, P = 0.0084), although the differences were not statistically significant. Our results indicate that OS-MS is a DPB 1*0501-associated subgroup of MS, and that DPB1*0501 is also correlated with risk of conventional MS in Japanese.

Adolescent↗

Dynamic viscoelastic properties and the age changes of long-term soft denture liners.

The dynamic viscoelastic properties of long-term soft denture liners were measured over a wide range of frequencies using a dynamic viscoelastometer based on a non-resonance-forced vibration principle. Changes in properties over a 3 yr period have also been monitored. One acrylic material, one fluoroelastomer, one heat cured silicone and one self-curing addition silicone were used. Complex dynamic tensile modulus (E*), tensile storage modulus (E'), tensile loss modulus (E") and loss tangent (tan delta) were determined over the frequency range from 0.01 to 100 Hz on administration of a 0.27% strain at 37 degrees C. The dynamic viscoelasticity of the acrylic and fluoroelastomer products was more sensitive to changes in frequency than that of silicone products. The acrylic material and fluoroelastomer exhibited viscoelastic behaviour whilst silicones exhibited elastic behaviour. The silicone products remained unchanged after soaking for 3 yr whilst the acrylic and fluoroelastomer products underwent significant change.

Acrylates↗

Genetics of multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. Although environmental risk factors are clearly involved in MS, the importance of genetic factors has been strongly supported by the results of studies on multiplex families, though a weak association with major histocompatibility complex (MHC) has been the only genetic feature of MS consistently observed to date. Other candidates genes have been pointed out, but none has been confirmed. Recent genome scans suggest that no single MS susceptibility locus is necessary or sufficient to cause MS, and this finding is compatible with a polygenic etiology. Furthermore, MS is a heterogeneous disorder, and thus different genes may influence its course or presentation. Actually, some candidate genes have been proposed, which contribute to the genotype-phenotype interactions in MS.

Cytokines↗

Both the HLA-CPB1 and -DRB1 alleles correlate with risk for multiple sclerosis in Japanese: clinical phenotypes and gender as important factors.

The purpose of this study was to clarify the association of HLA-DRB1 and -DPB1 alleles with multiple sclerosis (MS) in Japanese, to determine whether optico-spinal MS (OS-MS) and conventional MS are immunogenetically distinct, and to verify the role of gender difference in HLA associations of MS. We studied HLA-DRB1 and -DPB1 polymorphisms in 166 Japanese patients with MS. Forty-seven patients were classified as having the optico-spinal MS (OS-MS) and 119 as having conventional MS. A lack of DPB1*0301 and a higher frequency of DPB1*0501 compared with controls (corrected P<0.0074; odds ratio=9.48) were found in OS-MS. By contrast, we found for the first time an association of DPB1*0301 with conventional MS in Japanese (corrected P=0.0444; odds ratio=3.28). Logistic analysis, adjusted for sex and age, revealed independent associations of DPB1*0301 (P=0.0004, adjusted odds ratio (aOR)=4.70), DPB1*0501 (P=0.0081, aOR= 2.50) and DRB1*1501 (P=0.0252, aOR=2.21) with conventional MS. However, the frequencies of DRB1*1501 and DPB1*0501 in male patients with conventional MS were equal to those in male controls while the DPB1*0301 frequency was increased in both male and female patients. We did not find any association of these HLA alleles with disease course and severity. In conclusion, OS-MS is a DPB1*0501-associated distinct subtype of MS, and DPB1*0301 is the most strongly associated allele with conventional MS in Japanese. In addition, gender plays an important role in HLA association with MS.

Alleles↗