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H Hamada

Publications and source records attributed to H Hamada.

At least 73 records · Page 4Linked to original sources
PubMed2001

Roles of nodal-lefty regulatory loops in embryonic patterning of vertebrates.

Nodal is a signalling molecule that belongs to the transforming growth factor-beta superfamily of proteins, and Lefty proteins are antagonists of Nodal signalling. The nodal and lefty genes form positive and negative regulatory loops that resemble the reaction-diffusion system. As a pair, these genes control various events of vertebrate embryonic patterning, including left-right specification and mesoderm formation. In this review, we will focus on recent studies that have addressed the roles of nodal and lefty in mouse development.

Animals↗
PubMed2001

Side-to-side arterial anastomosis model in the rat internal and external carotid arteries.

Microvascular anastomosis has become a general and essential technique in the field of vascular reconstructive surgery. Side-to-side microvascular anastomosis is rarely performed by microsurgeons. Laboratory training models are essential for the development and refinement of microsurgical techniques. A new experimental model of a side-to-side "arterial" anastomosis in the rat internal and external carotid arteries is presented, in which 100 percent patency was accomplished immediately, and was maintained 7 days after anastomosis. This model can provide an experimental and training tool for side-to-side anastomosis of small arteries.

Anastomosis, Surgical↗
PubMed2001

Caspase-9 transduction overrides the resistance mechanism against p53-mediated apoptosis in U-87MG glioma cells.

OBJECTIVE: Conflicting reports have been published with regard to the relationship between the efficacy of p53 gene therapy and the p53 status of gliomas. In this study, we evaluated whether U-87MG glioma cells harboring wild-type p53 and U251 and U-373MG glioma cells harboring mutated p53 demonstrate different sensitivities to p53-induced apoptosis. In addition, we tested whether transduction of Bax or caspase-9, which are downstream components of p53-induced apoptosis, can override the resistance mechanism of U-87MG cells to apoptosis. METHODS: We transduced U-87MG, U251, and U-373MG glioma cells with p53, Bax, or caspase-9 genes via adenovirus (Adv) vectors, to induce the same level of respective proteins, and evaluated the degree of apoptosis. RESULTS: U-87MG cells were highly resistant to Adv for p53 (Adv-p53)-mediated apoptosis, whereas U251 and U-373 cells underwent extensive apoptosis after Adv-p53 infection. In U-87MG cells, the elevation of Bax and Fas was not as marked as that observed in U251 and U-373MG cells after Adv-p53 infection. Endogenous expression of Bcl-XL and Bcl-2 in U-87MG cells was greater than that in U251 and U-373MG cells. U-87MG cells were more resistant to Bax-mediated apoptosis than were U251 or U-373MG cells. In contrast, U-87MG cells were more sensitive to caspase-9-mediated apoptosis than were U251 or U-373MG cells, suggesting that transduction of caspase-9 may override the resistance mechanism of U-87MG to p53-mediated apoptosis. CONCLUSION: These results demonstrate that proapoptotic function induced by p53 transduction in U-87MG cells was repressed at several steps and that induction of caspase-9 may circumvent this resistance mechanism.

Apoptosis↗
PubMed2001

Sarcoidosis associated with psoriasis vulgaris.

We report a 70-year-old patient with sarcoidosis associated with psoriasis vulgaris. He had a nodule on the medial lower lid of his right eye. Oral corticosteroid for the sarcoid lesions and oral PUVA for psoriasis were employed. The cutaneous lesion disappeared within two months after starting the therapy. No relapse of sarcoidosis has been seen for eight years. The association of sarcoidosis with psoriasis has been previously reported; however, it is still unclear whether this association coincidental or meaningful.

Aged↗
PubMed2001

Co-transduction of Apaf-1 and caspase-9 augments etoposide-induced apoptosis in U-373MG glioma cells.

Several apoptosis-related genes have been reported to be involved in chemotherapy-induced apoptosis in cancers. An assessment of the relationship between expression of those genes and the degree of chemotherapy-induced apoptosis may be useful in improving the efficacy of cancer therapy. We transduced Apaf-1 (apoptotic protease-activating factor-1) and caspase-9 into U-373MG glioma cells using adenovirus (Adv) vectors in the presence of etoposide and evaluated the degree of apoptosis. The degree of apoptosis in etoposide-treated U-373MG cells infected with Adv for Apaf-1 (Adv-APAF1) was higher (27%) than that in cells infected with control Adv (14%), that in cells infected with Adv for caspase-9 (Adv-Casp9) was higher (34%) than that in cells infected with Adv-APAF1, and that in cells infected with both Adv-APAF1 and Adv-Casp9 was the highest (41%). Treatment with etoposide increased expression of p53 and decreased expression of Bcl-X(L) in U-373MG cells which harbored mutant p53. These results indicate that the expression of Apaf-1 and caspase-9 may be important determinants in predicting the sensitivity of cancers to chemotherapy. Adv-mediated co-transduction of Apaf-1 and caspase-9 should render cancer cells highly sensitive to chemotherapy.

Adenoviridae↗
PubMed2001

Glucose intolerance, plasma insulin levels, and colon adenomas in Japanese men.

Hyperinsulinemia may be related to colon carcinogenesis. Several studies have suggested that diabetes mellitus is related to increased risk of colon cancer. We examined cross-sectionally the relation of fasting plasma insulin levels and glucose tolerance status to colon adenomas. In a consecutive series of 951 men undergoing total colonoscopy for a health examination at the Japan Self Defense Forces Fukuoka Hospital from April 1998 to August 1999, we identified 233 cases of colon adenomas and 497 controls with normal colonoscopy. Glucose tolerance status was determined by a 75-g oral glucose tolerance test, and subjects were classified as normal, impaired glucose tolerance (IGT) or non-insulin dependent diabetes mellitus (NIDDM). Plasma insulin levels were measured after subjects had fasted overnight. Logistic regression analysis and analysis of covariance was used to control for age and obesity. While plasma insulin levels were unrelated to colon adenomas, NIDDM was associated with a significantly increased risk of colon adenomas. There was no association between IGT and colon adenomas. NIDDM was more strongly associated with proximal colon adenomas. The findings suggest that long-term hyperinsulinemic status associated with NIDDM may increase the risk of colon adenomas, and subsequently of colon cancer.

Adenoma↗
PubMed2001

Rapid detection of chromosome aneuploidies by prenatal interphase FISH (fluorescence in situ hybridization) and its clinical utility in Japan.

OBJECTIVE: The purpose of this study was to assess the accuracy, informative rate, detection rate, and clinical utility of prenatal interphase fluorescence in situ hybridization (FISH) analysis of amniotic fluid samples from Japanese women. METHODS: Amniotic fluid specimens from 2,639 Japanese women were received for prenatal interphase FISH and chromosome analysis. A questionnaire was designed to evaluate FISH clinical utility by collaboration sites. RESULTS: Based on 2,319 tested samples, the accuracy (100%), informative (94%), and detection (87.6%) rates were all high. The accuracy (100%), informative (90.2%), and detection (90.0%) rates were also remarkable in third-trimester pregnancies. We perceive significant advantages from this test regarding medical management and patient satisfaction. CONCLUSIONS: This novel report shows that in Japan prenatal interphase FISH testing is highly informative and accurate, not only in second-trimester pregnancies but also in third-trimester pregnancies. This test provides advantages to both physicians and patients, provided that its capabilities and limitations are understood.

Adult↗
PubMed2001

Robustness to head misalignment of virtual sound imaging systems.

When binaural sound signals are presented with two loudspeakers, the listener's ears are required to be in the relatively small region which is under control of the system. Misalignment of the head results in inaccurate synthesis of the binaural signals. Consequently, directional information associated with the acoustic signals is inaccurately reproduced. When the two loudspeakers are placed close together, the spatial rate of change of the generated sound field is much smaller than that generated by two loudspeakers spaced apart. Therefore, the performance of such a system is expected to be more robust to misalignment of the listener's head. Robustness of performance is investigated here with respect to head displacement in three translational and three rotational directions. A comparison is given between systems consisting of two loudspeakers either placed close together or spaced apart. The extent of effective control with head displacement and the resulting deterioration in directional information is investigated in the temporal and spectral domain by analyzing synthesized binaural signals. Subjective localization experiments are performed for cases in which notable differences in performance are expected from the previous analysis. It is shown that the system comprising two loudspeakers that are close together is very robust to misalignment of the listener's head.

Acoustics↗
PubMed2001

Prolonged antigen exposure ameliorates airway inflammation but not remodeling in a mouse model of bronchial asthma.

BACKGROUND: In naive rodents, repeated exposure to aerosolized antigen induces suppression of the Th2 response to the antigen. We hypothesized that more prolonged exposure of established asthma model to antigen aerosols may downregulate asthmatic phenotype. METHODS: After establishing an ovalbumin (OVA)-induced asthma model, mice were further exposed to OVA (prolonged exposure group) or phosphate-buffered saline (positive controls) 3 days per week for 6 weeks. During week 7, the mice of both groups were finally challenged with OVA. RESULTS: Prolonged OVA exposure resulted in marked suppression of serum OVA-specific immunoglobulin E (IgE) antibody levels, eosinophilia of the airway, and airway hyperresponsiveness (AHR). However, airway remodeling characterized by goblet cell hyperplasia and airway fibrosis was observed to the same degree in both groups. These effects were accompanied by diminished production of Th2 cytokines such as interleukin-4 (IL-4), IL-5 and IL-13 in bronchoalveolar lavage fluid (BALF) and cultured supernatant of splenocytes. Furthermore, prolonged exposure markedly increased IL-12 levels in BALF. CONCLUSIONS: Prolonged antigen exposure has inhibitory effects on eosinophilic inflammation, AHR and IgE response to antigen, but not on airway remodeling, presumably via inhibition of Th2 cytokines and increased IL-12 production in the lungs.

Animals↗
PubMed2001

5-hydroxytryptamine strongly inhibits fluid secretion in guinea pig pancreatic duct cells.

We studied the distribution of 5-hydroxytryptamine- (5-HT-) containing cells in the guinea pig pancreas and examined the effects of 5-HT on fluid secretion by interlobular pancreatic ducts. The 5-HT-immunoreactive cells with morphological characteristics of enterochromaffin (EC) cells were scattered throughout the duct system and were enriched in islets of Langerhans. The fluid secretory rate in the isolated interlobular ducts was measured by videomicroscopy. Basolateral applications of 5-HT strongly but reversibly reduced HCO(3)-dependent, as well as secretin- and acetylcholine- (ACh-) stimulated, fluid secretion, whereas 5-HT applied into the lumen had no such effects. Secretin-stimulated fluid secretion could be inhibited by a 5-HT(3) receptor agonist, but not by agonists of the 5-HT(1), 5-HT(2), or 5-HT(4) receptors. Under the stimulation with secretin, 5-HT decreased the intracellular pH (pH(i)) and reduced the rate of pH(i) recovery after acid loading with NH(4)(+), suggesting that 5-HT inhibits the intracellular accumulation of HCO3(-). The elevation of intraductal pressure in vivo reduced secretin-stimulated fluid secretion, an effect that could be attenuated by a 5-HT(3) receptor antagonist. Thus, 5-HT, acting through basolateral 5-HT(3) receptors, strongly inhibits spontaneous, secretin-, and ACh-stimulated fluid secretion by guinea pig pancreatic ducts. 5-HT released from pancreatic ductal EC cells on elevation of the intraductal pressure may regulate fluid secretion of neighboring duct cells in a paracrine fashion.

Acetylcholine↗
PubMed2001

High throughput prediction of oral absorption: improvement of the composition of the lipid solution used in parallel artificial membrane permeation assay.

The purpose of the present study was to improve the composition of the lipid solution used in parallel artificial membrane permeation assay for the precise prediction of oral absorption. We modified the composition of lipid solution, which was used to make a lipid membrane on the filter support. First, we changed the chain length of organic solvent (PC/alkyldienes [C7-C10]). A negative charge was then added to the membrane to mimic the intestinal membrane (PC/stearic acid/1,7-octadiene and PC/PE/PS/PI/cholesterol/1,7-octadiene). Finally, we examined the predictability of the PC/PE/PS/PI/CHO/1,7-octadiene membrane using structurally diverse compounds. Permeability coefficients of tested compounds were increased as the chain length of alkyldiene became shorter. The addition of a negative charge to the membrane increased the permeability of the basic compounds. However, the negatively charged membrane with stearic acid showed different permeability profiles from PC/PE/PS/PI/CHO. The predictability of the PC/PE/PS/PI/CHO/1,7-octadiene membrane was adequate (r = 0.858, n = 31) for use during the early stages of the drug discovery/development process.

Absorption↗
PubMed2001

A walking stick for a pure akinesia patient.

We describe a 63-year-old female patient with pure akinesia whose gait was facilitated by a handmade converted walking stick. A posterior ventral pallidotomy had been performed, but it did not alleviate symptoms. Her husband made a walking stick with a wire loop at the bottom, perpendicular to the walking direction. When the patient stepped over the loop, the frozen gait was improved. This converted walking stick is easily made and inexpensive. Although the walking stick did not improve the patient's gait radically, use of the converted walking stick effectively improved the patient's daily life because successful treatment of pure akinesia cannot be established.

Canes↗
PubMed2001

Functional glucosylation of kojic acid and daidzein with the Eucalyptus membrane-associated UDP-glucosyltransferase reaction system.

Kojic acid was glucosylated to kojic acid 5- and 7-O-beta-D-glucopyranosides by cultured cells of Eucalyptus perriniana. The glucosylation was also performed effectively by the enzymatic reaction system using membrane-associated UDP-glucosyltransferase from the cells with addition of UDP-glucose. The production of the 5-O-D-glucoside occurred exclusively prior to that of the 7-O-glucoside in both systems. In the same manner, daidzein was converted to daidzin (daidzein 7-O-beta-D-glucopyranoside) by the enzymatic system. Here, we propose methods for the structural modification of phytoestrogen-related substances by enzymatic beta-glucosylation.

Journal Article↗
PubMed2001

Mixed connective tissue disease associated with von Recklinghausen's neurofibromatosis.

We report a 42-year-old Japanese woman with Recklinghausen's neurofibromatosis 1 (NF1) who developed mixed connective tissue disease (MCTD). Previously experiencing good health without an increase in subcutaneous nodules, she presented with Raynaud's phenomenon, swollen hands and polyarthralgia Clinical examination revealed a high titer of anti-RNP antibody, and she was thus diagnosed as having MCTD. She was treated with oral prednisolone (10 mg/day) and her symptoms improved rapidly. Since the association of MCTD and NF1 has not been reported previously, we concluded that this association is rare. We also discussed the association of NF1 and autoimmune diseases including MCTD.

Adult↗
PubMed2001

Severe inclusion body myositis with interstitial pneumonia.

We report a patient with a severe inclusion body myositis (IBM). His illness was unusual in terms of a rapid progression, high creatine kinase levels, and complication with interstitial pneumonia. He responded well to immunosuppressive agents such as corticosteroids, cyclosporin A, cyclophosphamide, and immunoglobulin. The present patient indicates the wide range of the disease, and that immunosuppressive agents may be useful for treatment of IBM.

Aged↗
PubMed2001

[A case of sarcoidosis with muscle nodules].

A 65-year-old man with sarcoidosis, accompanied by muscle nodules, noticed a painless and enlarged nodule in his forearm. MRI of the nodule showed that a star-shaped area of lower signal intensity was surrounded by an area of higher signal intensity. Histological examination showed granulomas composed of multinuclear giant cells and epithelioid cells. Sarcoidosis was diagnosed. Eight months later, he was admitted to our hospital because of enlargement of the nodular region with pain and stiffness. Marked uptake of 67Ga was observed in the right arm and leg. MRI revealed sarcoid nodules in these regions. An enlargement of the higher signal intensity area was observed in the right forearm nodule. We started administration of prednisolone. Forty days later, his symptoms had disappeared and the size of higher signal intensity area of the nodule had reduced dramatically. 67Ga scintigram and MRI were useful for diagnosis and monitoring during therapy in this patient.

Aged↗
PubMed2001

Establishment and characterization of a novel malignant astrocytoma cell line derived from a tumor removed in a patient with neurofibromatosis type 1.

OBJECT: Patients with neurofibromatosis Type 1 (NF1) have a predisposition to development of a variety of benign and malignant tumors including neurofibromas, astrocytomas, pheochromocytomas, and malignant peripheral nerve sheath tumors. The availability of an astrocytoma cell line derived from NF1 would be useful in studies in which sporadic astrocytomas could be compared with NF1-derived astrocytomas. In this article the authors describe a novel astrocytoma cell line, TM-31, that they established from a tumor removed in a 42-year-old woman with NF1. METHODS: The TM-31 cell line was prepared from a surgical specimen of malignant astrocytoma and was serially subcultured over 250 times throughout a 6-year period without showing any sign of cell senescence. Immunocytochemical analyses demonstrated that TM-31 cells are negative for glial fibrillary acidic protein but positive for vimentin and S-100 protein. The TM-31 cells display little neurofibromin expression when subjected to immunoblotting, indicating that there is an NF1 gene mutation. Polymerase chain reaction-single-strand conformational polymorphism analysis revealed that TM-31 cells harbor a p53 point mutation in exon 7, codon 238. Chemosensitivity testing of TM-31 cells revealed a resistance to 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea, although they are sensitive to cisplatin and etoposide. In addition, TM-31 cells displayed no morphological differentiation after all-transretinoic acid and dibutyryl cyclic adenosine monophosphate treatments. Pharmacological inhibition of farnesyltransferase of the Ras oncoprotein led to decreased proliferative activity and inhibition of anchorage-independent growth of TM-31 cells in soft agar. CONCLUSIONS: The TM-31 cell line is an immortalized astrocytoma cell line derived from a tumor obtained in a patient with NF1. Ras activation may be the major event of proliferative activity and of the transformed phenotype of TM-31 cells, and the farnesyltransferase inhibitor may be potentially important as a novel antiproliferative therapy for NF1-derived astrocytomas.

Astrocytoma↗