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T Tada

Publications and source records attributed to T Tada.

At least 55 records · Page 3Linked to original sources
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↗
PubMed2001

Association of allelic losses at 3p25.1, 13q12, or 17p13.3 with poor prognosis in breast cancers with lymph node metastasis.

To identify specific allelic losses that might correlate with postoperative mortality of patients with node-positive breast carcinomas, we examined tumors from a cohort of 263 such patients, who were followed clinically for 5 years postoperatively, for allelic losses among 18 microsatellite markers. Patients whose tumors had lost an allele at 3p25.1, 13q12, or 17p13.3 had significantly higher risks of mortality than those whose tumors retained both alleles at those loci. At 3p25.1, the 5-year mortality rate was 33.8% among patients with losses vs. 16.8% with retention (P = 0.0154); at 13q12, 30.3% vs. 13.0% (P = 0.0241); and at 17p13.3, 30.4% vs. 16.2% (P = 0.0243). Combined losses at 3p25.1 and 17p13.3 increased the predicted postoperative mortality risk by a factor of 4.9 (5-year mortality rate of 38.2% vs. 8.0%, P = 0.0006), and combined losses at 3p25.1 and 13q12 raised the predicted postoperative mortality risks by a factor of 2.9 (34.7% vs. 12.7%, P = 0.0441). These data indicate that loss of heterozygosity (LOH) at any one or a pair of loci at 3p25.1, 13q12, or 17p13.3 is a significant predictor of postoperative mortality for breast-cancer patients.

Adult↗
PubMed2001

Involvement of mu-calpain in human sperm capacitation for fertilization.

PROBLEM: The distribution and physiological role of calpains in human sperm were investigated. METHOD OF STUDY: Semen collected manually from healthy donors was liquefied then centrifuged by percoll gradient centrifugation. After exposure to different concentrations of Ca2+ ionophore A23187, the samples were used for immunostaining sodium dodecyl sulfate polyacrylamide gel electrophoresis, and western blot analysis. It was speculated from the results of the study using calpain-specific inhibitors that calpain contributes to the sperm motility and acrosome reaction. RESULTS: With the anti-pro mu-calpain antibody, sperm were immunostained, whereas all were negative for anti-pro mu-calpain antibody binding. Stained sperm were classified into four types according to the staining pattern: acrosome type, equatorial segment type, whole head type, and neck and tail segments type. Western blot analysis of sperm homogenate revealed a single 80-kDa band using the anti-pro mu-calpain antibody, its dose-dependent reduction with Ca2+ ionophore A23187 suggesting activation by this treatment. In the presence of membrane permeable calpain inhibitors, sperm motility and acrosome reaction were significantly suppressed. CONCLUSION: These results indicate that mu-calpain may play pivotal roles in the process of fertilization of human sperm.

Amino Acid Sequence↗
PubMed2001

Effect of probucol in lecithin-cholesterol acyltransferase-deficient mice: inhibition of 2 independent cellular cholesterol-releasing pathways in vivo.

Cellular cholesterol release takes place by at least 2 distinct mechanisms: the lecithin-cholesterol acyltransferase (LCAT)-driven net efflux by cholesterol diffusion and the generation of high density lipoprotein (HDL) with cellular cholesterol and phospholipid on the cell-apolipoprotein interaction. Therefore, LCAT deficiency impairs the former pathway, and the latter can be inhibited by probucol, which interferes with the apolipoprotein-cell interaction. Hence, probucol was given to the LCAT-deficient mice in the attempt to suppress both of these pathways. The mice were fed low (0.2%) and high (1.2%) cholesterol diets containing 0.5% probucol for 2 weeks. LCAT deficiency and probucol markedly decreased plasma HDL, and the effects were synergistic. Tissue cholesterol content was lower in the adrenal glands and ovaries in the LCAT-deficient mice and in the probucol-treated mice, suggesting that HDL is a main cholesterol provider for these organs. It was also moderately decreased in the spleen of the low cholesterol-fed female mice and in the thyroid gland of the low cholesterol-fed male mice. On the other hand, the esterified cholesterol content in the liver was substantially increased by the probucol treatment with a high cholesterol diet in the LCAT-deficient mice but not in the wild-type mice. Among the groups, there was no significant difference in the tissue cholesterol levels in other organs, such as the liver, spleen, thymus, brain, erythrocytes, thyroid gland, testis, and aorta, resulting from either LCAT deficiency or probucol. Thus, the apolipoprotein-mediated mechanism plays a significant role in the export of cellular cholesterol in the liver, indicating that the liver is a major site of the HDL assembly. Otherwise, tissue cholesterol homeostasis can largely be maintained in mice even when the assembly of new HDL is inhibited by probucol in the absence of LCAT. Nonspecific diffusion of cholesterol perhaps adequately maintains the homeostasis in the experimental condition.

Animals↗
PubMed2001

Inflammatory cytokine cascade released by leukocytes in cerebrospinal fluid after subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) elicits an inflammatory response in the subarachnoid space, which is mediated by the release of various cytokines. To assess their involvement in post-hemorrhagic complications, we determined the source and time-course of the release of inflammatory cytokines and acute-phase proteins in cerebrospinal fluid (CSF) following SAH. Concentrations of interleukin (IL)- 1beta, IL-6, transforming growth factor-beta1 (TGF-beta1) and C-reactive protein (CRP) in CSF of 36 patients with SAH were measured by enzyme-linked immunoabsorbent assay (ELISA). Floating cells collected from the CSF were centrifuged four to six days after SAH, and examined immunohistochemically. Intracellular IL-1beta and IL-6 were examined by flow cytometric analysis. The molecular weight of TGF-beta1 in CSF of 30 patients was examined by Western blot analysis. The TGF-beta1 levels of patients who had undergone ventriculoperitoneal (VP) shunt (n = 19) was significantly higher than nonshunt group (n = 16). The CRP levels of VP shunt group was significantly higher than nonshunt group. IL-6 concentration was maximal within day 0-1 and it was secreted by neutrophils and monocytes. ELISA showed consistently low levels of IL-1beta, whereas a proportion of monocytes and lymphcytes were IL- 1beta-positive by flow cytometric analysis. TGF-beta1 levels were also maximal on day 0-1 according to ELISA, although it tended to be in the inactive form derived from platelets. A 25 kDa band of TGF-1 was detectable for at least 13 days after SAH, which may have been secreted in part by neutrophils and monocytes. CRP levels in CSF peaked on day 2-3. The present results suggest that leukocytes induced by SAH play an important role in post-hemorrhagic inflammation in the subarachnoid space by releasing IL-6 and TGF-beta1. The CRP and TGF-beta1 levels in CSF are strongly concerned with communicating hydrocephalus after SAH.

Adult↗
PubMed2001

Toti-/pluripotential stem cells and epigenetic modifications.

The recent fascinating breakthrough in the area of stem cell research is the successful production of cloned animals via nuclear transplantation of somatic nucleus by intrinsic trans-acting factors of oocytes and trans-differentiation of somatic stem cells from adult organs induced by extrinsic growth factors. During the process of nuclear reprogramming, epigenetic modification of the somatic nuclei must be achieved to acquire toti-/pluripotential competence. However, the molecular mechanism involved is largely unknown. It has been shown that DNA methylation, histone acetylation and chromatin structure are involved in the establishment of epigenetic modification. Now it is evident that they function cooperatively to establish and maintain active or inactive chromatin state. Here we discuss the mechanisms of epigenetic modification potentially involved in the event of nuclear reprogramming.

Animals↗
PubMed2001

[Sentinel node detection of patients with breast cancer by radionuclide method: consideration of radiation safety].

Sentinel node was detected by 99mTc labeled nanocolloid in five patients with breast cancer. Surgery of breast cancer was done at 16 hours after the administration of 74 MBq of 99mTc labeled nanocolloid. Sentinel node was searched by scintigraphy prior to surgery and by gamma-probe during surgery. Radioactivity of injected site, sentinel nodes, blood contaminated gauze, and other garbage was measured by GM detector. Radiation to medical staffs was monitored by a pocket radiation detector and film batches. Sentinel nodes were successfully detected both by scintigraphy and gamma-detector. More than 70% of radioactivity remained in the administered site at 16 hours. Small amount of radioactivity was detectable in the sentinel node. Almost no radioactivity was detectable in blood-contaminated gauze and other garbage. Radiation dose to the main surgeon was 4 to 6 microSv per surgery by a pocket radiation detector. Radiation dose to the assistant surgeon was 2 microSv per surgery. Radiation dose by labeling or injection was 0 to 1 microSv per procedure. No detectable radiation was measured by film batches. It is concluded that the detection of sentinel node by 99mTc labeled nanocolloid is a safe procedure from the point of radiation safety consideration.

Breast Neoplasms↗
PubMed2001

Biosynthetic response of cultured articular chondrocytes to mechanical vibration.

The objective of this study was to determine the effects of mechanical vibration loading on DNA and proteoglycan syntheses in cultured rabbit articular chondrocytes. Chondrocyte culture plates were placed in a vibratory apparatus and subjected to a mechanical vibratory load at various frequencies and periods in culture. Mechanical vibration was applied at a sinusoidal waveform of 1.4 g acceleration with frequencies of 200, 300, 400, 800, and 1600 Hz. 3H-Thymidine and H2(35)SO4 incorporation were used to detect radiolabeled DNA and proteoglycan syntheses, respectively. A frequency of 300 Hz showed a time-dependent augmentation of DNA synthesis and gave a maximal increase at day 3 with periodic vibration (8 h per day) and at 72 h or longer with continuous vibration. It also promoted proteoglycan synthesis in long-term culture (from 3 to 15 days) by periodic vibration. However. frequencies above 400 Hz suppressed biosynthesis. These results suggest that mechanical vibration at certain frequencies may modulate biosynthetic response of articular chondrocytes.

Animals↗
PubMed2001

[Clinical efficacy of magnetic resonance cholangiopancreatography in the diagnosis of biliary tract diseases].

This study was carried out to clarify the efficacy of magnetic resonance cholangiopancreatography (MRCP) in the diagnosis of biliary tract diseases, Three hundred and eleven patients who underwent MRCP and ERCP during the period from January 1999 to December 1999 at our institution were included in the study. Two gastroenterologists who were blinded to results of direct cholangiography and final diagnoses interpreted MRCP images prospectively. The biliary duct was visualized by MRCP and ERCP in 99.4% and 89.5% of the cases, respectively. The sensitivity, specificity, and accuracy of MRCP in the diagnosis of choledocholithiasis were 95%, 97%, and 97%, respectively. MRCP depicted the presence of strictures with a sensitivity, specificity, and accuracy of 97%, 96%, and 96%, respectively. There were three false-positive cases because of artifacts from arterial compression, The accuracy of MRCP and ERCP in differentiation of benign strictures from malignant ones was 85% and 96%, respectively. Based on these results, it is concluded that MRCP has high capability in visualization of the biliary tree, and in detection of stones and strictures, To avoid over and under-diagnosis, awareness of some pitfalls inherent in, MRCP is important. We suggest that MRCP should be recommended for patients with suspicion of biliary tract diseases in the initial stage of making diagnosis.

Adult↗
PubMed2000

Adaptive evolution of the African and Indonesian coelacanths to deep-sea environments.

We have PCR amplified and sequenced the rhodopsin (RH1) and evolutionarily closely related RH2 genes of the Indonesian coelacanth, now referred to as Latimeria menadoensis. When the RH1 and RH2 coding sequences are constructed, expressed in cultured cells, and reconstituted with 11-cis-retinal, the resulting visual pigments have wavelengths of maximal absorption (lambda(max)) of 485 and 479 nm, respectively. These lambda(max) values are identical to those of the African coelacanth, Latimeria chalumnae, showing that the Indonesian coelacanths also detect a narrow range of color. Statistical analyses show that the adaptation of the coelacanths toward the deep-sea started as early as 200 million years ago.

Adaptation, Physiological↗
PubMed2000

Structure of porcine pancreatic elastase complexed with FR901277, a novel macrocyclic inhibitor of elastases, at 1.6 A resolution.

Human leukocyte elastase (HLE) is a serine protease that contributes to tissue destruction in various disease states-for example, in emphysema. FR901277 is a natural product isolated from the culture filtrate of Streptomyces resistomicificus and is a potent inhibitor of both HLE and porcine pancreatic elastase (PPE). FR901277 consists of four normal amino acids and three unusual amino acids, and is a unique bicyclic peptide compound. The crystal structure of PPE complexed with FR901277 has been determined at 1.6 A resolution. The Ogamma atom of Ser-195 in PPE did not form a covalent bond with FR901277, but formed a hydrogen bond with the Nvarepsilon atom of His-57. On the other hand, the portion from L-Orn(1) through dehydroxyThr(3) in FR901277 formed an antiparallel beta-sheet structure with the backbone of the active site in PPE. The S4 through S2' binding subsites in PPE were all occupied by the hydrophobic side chains of the inhibitor molecule. Especially, the ethylidene moiety of FR901277 occupied the S1 specific pocket, indicating a CH/pi interaction. In addition, the isopropyl side chain of L-Val(7) was located at the enzyme surface between the S2 and S1' pockets with several van der Waals contacts. However, the amino acid (4) residue was not involved in a significant interaction with PPE. Comparison of inhibitor structures in different environments showed that FR901277 has a highly rigid bicyclic framework; however, it can slightly change its conformation according to the circumstances. The binding mode of FR901277 at the active site of PPE was directly applicable to that in HLE, after consideration of induced fit. The structure of the PPE-FR901277 complex provided much information regarding potential sites for modification of the physicochemical properties of FR901277.

Amides↗
PubMed2000

2,2'-Spirobi(1,3-benzodithiole).

The X-ray structure analysis of 2,2'-spirobi(1,3-benzodithiole), C(13)H(8)S(4), has been performed. The molecule has crystallographic twofold rotation symmetry, the axis passing through the spiro-C atom. The four S atoms are arranged around the spiro-C atom in two almost orthogonal CS(2) planes. However, because of large bending of the two five-membered rings, close contact is present between two connected C atoms on the benzo group of each 1,3-benzodithiole ring and one S atom on the other 1,3-benzodithiole ring.

Journal Article↗