Search PubMed⌕ Search

Biomedical subjects

T Tada

Publications and source records attributed to T Tada.

At least 37 records · Page 2Linked to original sources
PubMed2001

Alpha-fetoprotein producing gastric cancer lacks transcription factor ATBF1.

Alpha-fetoprotein (AFP) producing gastric cancer (AFP-GC) is very malignant and highly metastatic compared with common gastric cancer. However, the causal relationship between AFP production and the high malignancy of AFP-GC is unclear. We investigated AFP gene regulation in AFP-GC by an active transcription factor, HNF1 (hepatocyte nuclear factor 1) and a repressive transcription factor, ATBF1 (AT motif binding factor 1). RNase protection assays revealed that the production of AFP in gastric cancer cells did not directly associate with HNF1 expression. An inverse relation between the expressions of ATBF1 and AFP was clearly observed in gastric cancer cells. CAT assays showed the direct inhibition of AFP gene expression by ATBF1. Methylation analysis of the AFP promoter region in gastric cancer cells suggested that methylation itself could not explain the silencing of the AFP gene. Immunohistochemistry of resected clinical samples revealed that AFP producing cells lacked ATBF1 immunoreactivity. Our data suggests that the absence of ATBF1 is responsible for AFP gene expression in gastric cancer, and the absence of ATBF1 is a distinct characteristic of AFP-GC and might be important for its highly malignant nature.

DNA Methylation↗
PubMed2001

Regulation of rat hippocampal neural cadherin in the kainic acid induced seizures.

Regulation of neural (N-) cadherin expression in the hippocampus was examined by in situ hybridization and immunohistochemistry methods in the rat model of kainic acid (KA) induced seizures. After 12 and 24 h of KA administration, mRNA expression level of N-cadherin decreased in the hippocampal CA1 and CA3 area in parallel with decrease of the number of neural cells. In contrast, after 48 h and 7 days, mRNA expression level recovered partially, although the number of neural cells remained small. In addition, immunohistochemical staining indicated that N-cadherin protein expression of survived neurons increased significantly after 48 h of KA administration. These results indicated that N-cadherin might be involved in neuronal reconstruction at the hippocampus.

Animals↗
PubMed2001

Network structure of curdlan in DMSO and mixture of DMSO and water.

The viscoelastic property of curdlan solution in dimethyl sulfoxide (DMSO) was investigated. We discuss the difference in the viscoelastic properties of curdlan solution in DMSO and that in 0.1 N NaOH aqueous solution. The viscoelastic function for curdlan solution in 0.1 N NaOH aqueous solution showed the Newtonian flow at the concentration of curdlan as high as 10 wt %. On the other hand, the Newtonian flow was observed in the concentrations below 7 wt % for curdlan solution in DMSO, and the plateau region appeared beyond this concentration. It was revealed by small angle x-ray diffraction measurements that the difference in the mechanical property would be originated from the difference in the network structure. The overlapping concentration c* was calculated on the basis of the mean field theory, and disagreement between theoretical prediction and experimental result was shown. We clarified that the above disagreement can be explained by the polydispersity of the curdlan sample, assuming adequate distribution functions. The static structure of the gel prepared by adding water to curdlan solution in DMSO was investigated. It was clarified by the dynamic viscoelasticity measurement that the cross-linking density increases with increasing the water content.

Dimethyl Sulfoxide↗
PubMed2001

Abnormal activity in the globus pallidus in off-period dystonia.

Pallidotomy was performed in a parkinsonian patient with off-period foot dystonia. Dystonia appeared at the beginning of surgery and disappeared after the first microelectrode penetration of the globus pallidus, perhaps a micropallidotomy effect. Neuronal recording during dystonia revealed that the mean firing rates were low in both the internal and external segments of the globus pallidus, and that firing was irregular in the internal segment of the globus pallidus, compared with firing patterns in offstate parkinsonian patients without dystonia. These firing patterns immediately changed into those of nondystonic, off-state parkinsonism after relief of dystonia These results suggest that off-period dystonia results from the same physiological change in the basal ganglia as that in primary dystonia.

Dystonia↗
PubMed2001

Neuronal activity in the globus pallidus in chorea caused by striatal lacunar infarction.

Pallidotomy was performed in a patient with hemichorea caused by lacunar infarction in the striatum. Chorea in the lower limb was reduced after a neurosurgical lesion in the medial portion of the sensorimotor territory of the internal segment of the globus pallidus, and chorea in the upper limb disappeared after an additional lesion in the lateral portion of that same area. Intraoperative neuronal recording revealed that mean firing rates were low, and that firing was irregular in the globus pallidus compared with off-state parkinsonian patients. These results suggest that chorea with striatal infarction is driven by phasic neuronal activity with a low firing rate in the globus pallidus and that the neural pathway of chorea has a functional somatotopical organization in the globus pallidus.

Action Potentials↗
PubMed2001

Establishment of embryonic stem cell lines from cynomolgus monkey blastocysts produced by IVF or ICSI.

Human embryonic stem (ES) cells are predicted to be a valuable source for producing ES-derived therapeutic spare tissues to treat diseases by controlling their growth and differentiation. To understand the regulative mechanisms of their differentiation in vivo and in vitro, ES cells derived from nonhuman primates could be a powerful tool. We established four ES cell lines from cynomolgus monkey (Macaca fascicularis) blastocysts produced by in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). The ES cells were characterized by the expression of specific markers such as alkaline phosphatase and stage-specific embryonic antigen-4. They were successfully maintained in an undifferentiated state and with a normal karyotype even after more than 6 months of culture. Pluripotential competence was confirmed by the formation of teratomas containing ectoderm-, mesoderm-, and endoderm- derivatives after subcutaneous injection into SCID mice. Differentiation to a variety of tissues was identified by immunohistochemical analyses using tissue-specific antibodies. Therefore, we established pluripotent ES cell lines derived from monkeys that are widely used as experimental animals. These lines could be a useful resource for preclinical stem cell research, including allogenic transplantation into monkey models of disease.

Animals↗
PubMed2001

Controlling the direction of kinesin-driven microtubule movements along microlithographic tracks.

Motor proteins are able to move protein filaments in vitro. However, useful work cannot be extracted from the existing in vitro systems because filament motions are in random directions on two-dimensional surfaces. We succeeded in restricting kinesin-driven movements of microtubules along linear tracks by using micrometer-scaled grooves lithographically fabricated on glass surfaces. We also accomplished the extraction of unidirectional movement from the bidirectional movements along the linear tracks by adding arrowhead patterns on the tracks. These "rectifiers" enabled us to construct microminiturized circulators in which populations of microtubules rotated in one direction, and to actively transport microtubules between two pools connected by arrowheaded tracks in the fields of micrometer scales.

Absorption↗
PubMed2001

Relation between changes in long-latency stretch reflexes and muscle stiffness in Parkinson's disease--comparison before and after unilateral pallidotomy.

OBJECTIVE: To study the effects of posteroventral pallidotomy on both the size of long-latency stretch reflex (LLR) and the muscle stiffness in the wrist flexor muscles. PATIENTS AND METHODS: Eleven consecutive patients (right-handed, 6 men and 5 women) underwent left-side microelectrode-guided pallidotomy. The LLR of the contralesional forearm was studied at baseline and 2-3 months after surgery while patients continued to take their optimal medical regimens ('on' period). Patients were instructed not to respond to the perturbation (passive mode) or to oppose the mechanical extensor perturbation (active mode). RESULTS: The stretch reflex evoked by extension perturbations of the wrist consisted of a short-latency reflex (M1) and an LLR (M2). Pallidotomy had no effects on the size of M1 components in both passive and active mode and on that of M2 component in the passive mode, however, it significantly reduced M2 component in the active mode (P<0.05). The inherent muscle stiffness over 60 ms period of mechanical stretch was not influenced by pallidotomy in any experimental condition (preoperative vs. postoperative or passive mode vs. active mode). The hand displacement following M2 component increased significantly after pallidotomy in both passive (P<0.005) and active mode (P<0.05). The inverted value of the displacement following M2 component correlated with the size of M2 component (r=0.60, P<0.001). CONCLUSIONS: Pallidotomy decreased the transcortical reflex gain, probably at cortical level, and consequently reduced muscle stiffness.

Adult↗
PubMed2001

Ruptured epidermoid cyst and haematoma of spleen: a diagnostic clue of high levels of serum carcinoembryonic antigen, carbohydrate antigen 19-9 and Sialyl Lewis x.

Splenic epidermoid cyst is a rare disease and that with haematoma is even more rare. The case of epidermoid cyst of the spleen is described, in a 36-year-old Japanese female, manifesting as left hypochondralgia and rupture of the cyst. Clinical features were splenic lesion 14 cm in diameter and consisting of round-hypovascular and crescent-hypervascular sublesions. Extravasation of cystic fluid was detected in abdominal cavity Preoperative diagnosis was difficult due to such uncommon features, however high levels of serum tumour markers (carcinoembryonic antigen, carbohydrate antigen 19-9, Sialyl Lewis x) strongly suggested epidermoid cyst. Laparotomic splenectomy and cholecystectomy were performed for splenic lesion and gallstones, and serum tumour markers decreased following surgery. Pathological diagnosis of the round-hypovascular lesion was epidermoid cyst and crescent-hypervascular lesion was haemorrhage (haematoma).

Adult↗
PubMed2001

Role of the epithelium in opposing H(2)O(2)-induced modulation of acetylcholine-induced contractions in rabbit intrapulmonary bronchiole.

1. The role played by the epithelium in H(2)O(2)-induced modulation of the mechanical responses induced by acetylcholine (ACh) in rabbit intrapulmonary bronchioles was investigated in epithelium-intact and -denuded strips. 2. When ACh (3 microM) was applied intermittently, H(2)O(2) (30 microM) enhanced the ACh-induced contractions in epithelium-intact strips. In contrast, in epithelium-denuded strips H(2)O(2) (30 microM) inhibited such contractions. At higher concentrations, H(2)O(2) concentration-dependently attenuated the ACh-induced contractions in both epithelium-intact and -denuded strips, its action being more potent in the latter strips than in the former. 3. Diclofenac (a cyclo-oxygenase inhibitor; 3 microM) reduced the H(2)O(2)-induced enhancement of ACh-contractions in epithelium-intact strips but had no effect on the H(2)O(2)-induced inhibition in epithelium-denuded strips. N(G)-nitro-L-arginine did not alter the effect of H(2)O(2) on ACh-induced contractions in epithelium-intact strips. 4. Catalase (500 u ml(-1)) completely blocked both H(2)O(2)-induced effects on ACh-contractions (enhancement and inhibition). Neither superoxide dismutase (200 u ml(-1)) nor deferoxamine (0.5 mM) had any effect on H(2)O(2)-induced inhibition in epithelium-denuded strips. 5. Aminotriazole (an inhibitor of catalase; 50 mM) significantly potentiated the H(2)O(2)-induced inhibition of ACh-contractions in epithelium-intact strips but not in epithelium-denuded strips. 6. The density ratio for catalase (epithelium-intact over -denuded strips) analysed by Western blot was about 2.1, suggesting that epithelium contains more catalase than smooth muscle. 7. It is concluded that in rabbit intrapulmonary bronchioles, H(2)O(2) has dual actions on ACh-contractions. It is suggested that the epithelium may act as a powerful biochemical barrier via both the action of catalase (scavenging H(2)O(2)) and the release of bronchoconstrictor prostaglandins, thus attenuating the H(2)O(2)-induced modulation of ACh-contractions.

Acetylcholine↗
PubMed2001

Successful primary reinforced repair of esophageal perforation using a pedicled omental graft through a transhiatal approach.

Esophageal perforation is potentially lethal if untreated. We report a case of distal esophageal perforation probably caused by swallowing a fish bone. The patient initially received conservative treatment 4 days after the esophageal injury. The treatment was promptly changed from conservative to operative treatment owing to rapid manifestation of suppurative mediastinitis followed by peritonitis. The patient successfully underwent primary repair of the perforation buttressed with a pedicled omental graft pulled up through the esophageal hiatus following a laparotomy. We discuss the validity of this method of transhiatal approach without thoracotomy for primary repair of distal esophageal perforation.

Aged↗
PubMed2001

Diagnosis of Toxoplasma meningoencephalitis in a non-AIDS patient using PCR.

We report herein a rare case of Toxoplasma gondii meningoencephalitis in a non-AIDS patient. Although T. gondii itself was not detected in nucleated cells in peripheral blood and cerebrospinal fluid under the microscope, the polymerase chain reaction method effectively detected the B1 gene of T. gondii in the cells. A serological examination showed increased levels of the IgG but not the IgM antibody to T. gondii, suggesting reactivation of the infection in the brain.

Animals↗
PubMed2001

Different keratin profiles in craniopharyngioma subtypes and ameloblastomas.

Craniopharyngiomas are generally considered to arise from the remnants of Rathke's pouch or a misplaced enamel organ. We tried to refine these hypotheses, comparing the subtypes of craniopharyngioma with Rathke's cleft cyst, a known Rathke's pouch derivative, and with ameloblastoma, an enamel organ derivative. Nineteen craniopharyngiomas (14 adamantinomatous and 5 papillary type tumors) and 17 ameloblastomas were immunostained for cytokeratin (CK) 7, CK 8, CK 14, and human hair keratin (HHK). All cases of adamantinomatous craniopharyngioma were CK 7+/CK 8+/CK 14+. Two cases (40%) of papillary craniopharyngioma were CK 7+/CK 8+/CK 14+, whereas the remaining three cases (60%) were CK 7+/CK 8-/CK 14+. Fifteen cases (88%) of ameloblastoma were CK 7-/CK 8+/CK 14+. Only the shadow cells present in adamantinomatous craniopharyngiomas were positive for HHK, which may indicate their follicular differentiation. In Rathke's cleft cyst, ciliated cuboidal cells were CK 7+/CK 8+/CK 14- and metaplastic squamous cells were CK 7+/CK 8/CK 14+. These findings suggest that both subtypes of craniopharyngioma may differ from ameloblastoma in histogenesis, although cytokeratin expression patterns may change during tumor development. Adamantinomatous craniopharyngioma may be related to a heterotopic ectodermal tissue which can differentiate into hair follicles, while papillary craniopharyngioma may arise from Rathke's cleft cyst.

Adolescent↗
PubMed2001

Atypical pleomorphic astrocytoma in the pineal gland: case report.

OBJECTIVE AND IMPORTANCE: We report a rare case of pleomorphic astrocytoma in the pineal region that took a benign course despite pleomorphism. CLINICAL PRESENTATION: A 30-year-old woman suddenly developed right hemiparesis followed by loss of consciousness. A computed tomographic scan revealed a mass in the pineal region accompanied by obstructive hydrocephalus. Her symptoms improved after ventriculoperitoneal shunt surgery. INTERVENTION: The tumor was totally removed in an en bloc fashion using the occipital interhemispheric transtentorial route. Light microscopy revealed that the tumor had marked pleomorphism and multinucleated, bizarre giant cells, but neither mitosis nor necrosis was seen. Glial fibrillary acid protein was immunohistochemically positive in a few tumor cells. Retinal soluble antigen was negative. No reticulin network between the tumor cells was observed. A histological diagnosis of atypical pleomorphic astrocytoma was made. CONCLUSION: No signs of recurrence have been observed for 7 years after surgery without adjuvant therapy. Histologically, the tumor resembled pleomorphic xanthoastrocytoma or pleomorphic granular cell astrocytoma, but the immunohistochemical findings were not completely compatible with either diagnosis. This benign astrocytoma in the pineal gland with unique features is the first such case reported.

Adult↗
PubMed2001

A uniform and one-dimensional stacking of 2,5-dichlorotetracyanoquinodimethanide molecules in the tetramethylarsonium salt.

In the tetramethylarsonium salt of 2,5-dichloro-7,7,8,8-tetracyanoquinodimethanide [systematic name: tetramethylarsonium 2,2'-(2,5-dichlorocyclohexa-2,5-diene-1,4-diylidene)bis(propanedinitrile)], C(4)H(12)As(+).C(12)H(2)Cl(2)N(4)(-) or [As(CH(3))(4)](C(12)H(2)Cl(2)N(4)), the cation lies disordered about a twofold axis and the radical ion lies about an inversion center forming a uniform [interplanar distance 3.35 (2) A] and one-dimensional stacking without any slip. The electrical conductivity of the single crystal at room temperature was less than 10(-9) S cm(-1), and the temperature dependence of paramagnetic susceptibility obeyed a one-dimensional antiferromagnetic Heisenberg model with a spin-exchange integral of 83 K in the temperature range 1.8-320.0 K.

Journal Article↗
PubMed2001

Crystallization and preliminary X-ray analysis of a novel pectolytic enzyme, polymethoxygalacturonase SX1 from Trichosporon penicillatum.

A novel pectolytic enzyme, polymethoxygalacturonase SX1 from Trichosporon penicillatum, with a molecular weight of 36 kDa was crystallized by the hanging-drop vapour-diffusion method using polyethylene glycol 1000 as a precipitant. The crystals belonged to the monoclinic space group C2, with unit-cell parameters a = 165.6, b = 61.0, c = 48.7 A, beta = 93.1 degrees. The calculated V(M) based on one molecule per asymmetric unit was 3.40 A(3) Da(-1). A native data set was collected to 2.08 A resolution from a crystal on a Cu Kalpha rotating-anode X-ray source. A molecular-replacement solution was obtained using the program AMoRe and the structure of endopolygalacturonase II from Aspergillus niger as a model.

Crystallization↗
PubMed2001

Purification, crystallization and preliminary X-ray diffraction analysis of the fructose-1,6-/sedoheptulose-1,7-bisphosphatase of Synechococcus PCC 7942.

Fructose-1,6-/sedoheptulose-1,7-bisphosphatase of Synechococcus PCC 7942, overexpressed from Escherichia coli, has been purified and crystallized by the hanging-drop vapour-diffusion method using ammonium sulfate as a precipitant. The crystals were monoclinic, with unit-cell parameters a = 80.1, b = 84.2, c = 104.3 A, beta = 101.7 degrees. They belonged to space group P2(1) and diffracted to at least 2.2 A resolution. The calculated V(M) value, based on a tetramer in the asymmetric unit, was 2.2 A(3) Da(-1).

Crystallization↗