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Biomedical subjects

T Wada

Publications and source records attributed to T Wada.

At least 55 records · Page 3Linked to original sources
PubMed2002

The effect of growth of nasopharyngeal structures in velopharyngeal closure in patients with repaired cleft palate and controls without clefts: a cephalometric study.

To clarify the changes with growth of nasopharyngeal structures involved in velopharyngeal closure, a cross-sectional study from early childhood to puberty was carried out in 61 patients with repaired unilateral cleft lip and palate showing complete velopharyngeal closure (cleft group) and 82 controls without clefts (control group). Measurements of the nasopharyngeal area were derived from a coordinate system and landmarks on lateral cephalograms, and results were analysed by multivariate analysis and t test. The adequate ratio (velar length to pharyngeal depth ratio) in the control group was maintained at a stable value, indicating that the ratio around 1.3 would be standard to maintain velopharyngeal closure. The vertical position of posterior maxilla, pharyngeal depth and velar length in the cleft group showed a different pattern of growth from those in the control group. There was, however, characteristic growth in both groups for maintenance of velopharyngeal closure.

Adolescent↗
PubMed2002

Entrapment neuropathy of the palmar cutaneous branch of the median nerve concomitant with carpal tunnel syndrome: a case report.

A case of the entrapment neuropathy of the palmar cutaneous branch of the median nerve, concomitant with carpal tunnel syndrome is presented. This report demonstrates that the Semmes-Weinstein monofilament test and nerve conduction studies can identify entrapment of the palmar cutaneous branch of the median nerve concomitant with carpal tunnel syndrome.

Carpal Tunnel Syndrome↗
PubMed2002

Valgus deformity of the ankle following harvesting of a vascularized fibular graft in children.

Progressive valgus ankle deformity is a problematic postoperative donor-site morbidity of a vascularized fibular graft in children. To prevent this complication, tibiofibular metaphyseal synostosis (the Langenskiöld procedure) has been recommended. The authors objectively evaluated the preventive and therapeutic effects of this procedure on five children who had received free vascularized fibular grafts. Their average age at the time of operation was 3 years (range: 1 to 9 years). The Langenskiöld procedure was performed primarily in four patients, and not in one patient. The anteroposterior (A-P) mortise angle and the empirical axis of the donor-site ankle were measured radiographically. With regard to the A-P mortise angle, four of five patients showed valgus with a mild lateral wedging of the distal tibial epiphysis. The patient who did not receive the operation showed the largest A-P mortise angle and mild osteoarthritic changes. The empirical axis exceeded normal range in all of the five patients. These observations indicated that valgus deformity of the ankle in children after harvesting a vascularized fibular graft is inevitable, even if the Langenskiöld procedure is performed. The procedure can delay the ankle valgus. The authors recommend close follow-up of the children who receive the Langenskiöld procedure after harvesting a vascularized fibular graft.

Adolescent↗
PubMed2001

Novel synthetic approach to 19-nor-1alpha,25-dihydroxyvitamin D(3) and its derivatives by Suzuki-Miyaura coupling in solution and on solid support.

19-nor-1alpha,25-Dihydroxyvitamin D(3) was synthesized by the Suzuki-Miyaura coupling of the A-ring intermediate 3, which was efficiently prepared from readily available 5-(tert-butyldimethylsilyl)oxycyclohex-2-enone (5), with the boronate compound of the C,D-ring portion. The method could be applied to a solid-phase synthesis to prepare the des-C,D derivatives of 19-nor-1alpha,25-dihydroxyvitamin D(3). [reaction: see text]

Calcitriol↗
PubMed2001

Synthesis of a muscarinic receptor antagonist via a diastereoselective Michael reaction, selective deoxyfluorination and aromatic metal-halogen exchange reaction.

An efficient synthesis of a structurally unique, novel M(3) antagonist 1 is described. Compound 1 is conveniently disconnected retrosynthetically at the amide bond to reveal the acid portion 2 and the amine fragment 3. The synthesis of key intermediate 2 is highlighted by a ZnCl(2)-MAEP complex 19 catalyzed diastereoselective Michael reaction of dioxolane 7 with 2-cyclopenten-1-one (5) to establish the contiguous quaternary-tertiary chiral centers and a subsequent geminal difluorination of ketone 17 using Deoxofluor in the presence of catalytic BF(3).OEt(2). The synthesis of the amine moiety 3 is highlighted by the discovery of a novel n-Bu(3)MgLi magnesium-halogen exchange reaction for selective functionalization of 2,6-dibromopyridine. This new and practical metalation protocol obviated cryogenic conditions and upon quenching with DMF gave 6-bromo-2-formylpyridine (26) in excellent yield. Further transformations afforded the amine fragment 3 via reductive amination with 35, Pd-catalyzed aromatic amination, and deprotection. Finally, the highly convergent synthesis of 1 was accomplished by coupling of the two fragments. This synthesis has been used to prepare multi-kilogram quantities of the bulk drug.

Amides↗
PubMed2001

First photosensitized enantiodifferentiating isomerization by optically active sensitizer immobilized in zeolite supercages.

Enantiodifferentiating photoisomerization of (Z)-cyclooctene sensitized by (R)- or (S)-1-methylheptyl benzoate immobilized in zeolite supercages afforded the respective enantiomer pair, (-)- and (+)-(E)-isomer (1E) in 5% enantiomeric excess, whilst racemic 1E was obtained upon homogeneous-phase photosensitization with the same antipodal sensitizer pair, thus demonstrating for the first time that chirally modified zeolites not only serve as supramolecular photosensitizing media but also enhance the original enantiodifferentiating ability of chiral photosensitizer.

Journal Article↗
PubMed2001

The stress kinase mitogen-activated protein kinase kinase (MKK)7 is a negative regulator of antigen receptor and growth factor receptor-induced proliferation in hematopoietic cells.

The dual specificity kinases mitogen-activated protein kinase (MAPK) kinase (MKK)7 and MKK4 are the only molecules known to directly activate the stress kinases stress-activated protein kinases (SAPKs)/c-Jun N-terminal kinases (JNKs) in response to environmental or mitogenic stimuli. To examine the physiological role of MKK7 in hematopoietic cells, we used a gene targeting strategy to mutate MKK7 in murine T and B cells and non-lymphoid mast cells. Loss of MKK7 in thymocytes and mature B cells results in hyperproliferation in response to growth factor and antigen receptor stimulation and increased thymic cellularity. Mutation of mkk7 in mast cells resulted in hyperproliferation in response to the cytokines interleukin (IL)-3 and stem cell factor (SCF). SAPK/JNK activation was completely abolished in the absence of MKK7, even though expression of MKK4 was strongly upregulated in mkk7(-/-) mast cell lines, and phosphorylation of MKK4 occurred normally in response to multiple stress stimuli. Loss of MKK7 did not affect activation of extracellular signal-regulated kinase (ERK)1/2 or p38 MAPK. mkk7(-/-) mast cells display reduced expression of JunB and the cell cycle inhibitor p16INK4a and upregulation of cyclinD1. Reexpression of p16INK4a in mkk7(-/-) mast cells abrogates the hyperproliferative response. Apoptotic responses to a variety of stimuli were not affected. Thus, MKK7 is an essential and specific regulator of stress-induced SAPK/JNK activation in mast cells and MKK7 negatively regulates growth factor and antigen receptor-driven proliferation in hematopoietic cells. These results indicate that the MKK7-regulated stress signaling pathway can function as negative regulator of cell growth in multiple hematopoietic lineages.

Animals↗
PubMed2001

A highly purified RNA polymerase II elongation control system.

Studying the sensitivity of transcription to the nucleotide analog 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole has led to the discovery of a number of proteins involved in the regulation of transcription elongation by RNA polymerase II. We have developed a highly purified elongation control system composed of three purified proteins added back to isolated RNA polymerase II elongation complexes. Two of the proteins, 5,6-dichloro-1-beta-d-ribofuranosylbenzimidazole sensitivity-inducing factor (DSIF) and negative elongation factor (NELF), act as negative transcription elongation factors by increasing the time the polymerase spent at pause sites. P-TEFb reverses the negative effect of DSIF and NELF through a mechanism dependent on its kinase activity. TFIIF is a general initiation factor that positively affects elongation by decreasing pausing. We show that TFIIF functionally competes with DSIF and NELF, and this competition is dependent on the relative concentrations of TFIIF and NELF.

Nuclear Proteins↗
PubMed2001

Specific tissue distribution of megsin, a novel serpin, in the glomerulus and its up-regulation in IgA nephropathy.

Mesangial cells play critical roles in maintaining a structure and function of the glomerulus. We previously cloned a novel mesangium-predominant gene, megsin, a new serine protease inhibitor. To clarify localization and roles of megsin protein, we raised polyclonal antibodies to megsin. By immunohistochemistry, megsin protein was specifically identified in the mesangial area. The amount of megsin protein was increased in glomeruli of patients with IgA nephropathy than in those of normal individuals and of patients with minimal change nephrotic syndrome or membranous nephropathy, suggesting a pathophysiological role of megsin as a functional modulator of mesangial functions in situ.

Amino Acid Sequence↗
PubMed2001

Increased susceptibility of decay-accelerating factor deficient mice to anti-glomerular basement membrane glomerulonephritis.

To prevent complement-mediated autologous tissue damage, host cells express a number of membrane-bound complement inhibitors. Decay-accelerating factor (DAF, CD55) is a GPI-linked membrane complement regulator that is widely expressed in mammalian tissues including the kidney. DAF inhibits the C3 convertase of both the classical and alternative pathways. Although DAF deficiency contributes to the human hematological syndrome paroxysmal nocturnal hemoglobinuria, the relevance of DAF in autoimmune tissue damage such as immune glomerulonephritis remains to be determined. In this study, we have investigated the susceptibility of knockout mice that are deficient in GPI-anchored DAF to nephrotoxic serum nephritis. Injection of a subnephritogenic dose of rabbit anti-mouse glomerular basement membrane serum induced glomerular disease in DAF knockout mice but not in wild-type controls. When examined at 8 days after anti-glomerular basement membrane treatment, DAF knockout mice had a much higher percentage of diseased glomeruli than wild-type mice (68.8 +/- 25.0 vs 10.0 +/- 3.5%; p < 0.01). Morphologically, DAF knockout mice displayed increased glomerular volume (516 +/- 68 vs 325 +/- 18 x 10(3) microm(3) per glomerulus; p < 0.0001) and cellularity (47.1 +/- 8.9 vs 32.0 +/- 3.1 cells per glomerulus; p < 0.01). Although the blood urea nitrogen level showed no difference between the two groups, proteinuria was observed in the knockout mice but not in the wild-type mice (1.4 +/- 0.7 vs 0.02 +/- 0.01 mg/24 h albumin excretion). The morphological and functional abnormalities in the knockout mouse kidney were associated with evidence of increased complement activation in the glomeruli. These results support the conclusion that membrane C3 convertase inhibitors like DAF play a protective role in complement-mediated immune glomerular damage in vivo.

Animals↗
PubMed2001

Somatic mosaicism in Wiskott--Aldrich syndrome suggests in vivo reversion by a DNA slippage mechanism.

Somatic mosaicism caused by in vivo reversion of inherited mutations has been described in several human genetic disorders. Back mutations resulting in restoration of wild-type sequences and second-site mutations leading to compensatory changes have been shown in mosaic individuals. In most cases, however, the precise genetic mechanisms underlying the reversion events have remained unclear, except for the few instances where crossing over or gene conversion have been demonstrated. Here, we report a patient affected with Wiskott--Aldrich syndrome (WAS) caused by a 6-bp insertion (ACGAGG) in the WAS protein gene, which abrogates protein expression. Somatic mosaicism was documented in this patient whose majority of T lymphocytes expressed nearly normal levels of WAS protein. These lymphocytes were found to lack the deleterious mutation and showed a selective growth advantage in vivo. Analysis of the sequence surrounding the mutation site showed that the 6-bp insertion followed a tandem repeat of the same six nucleotides. These findings strongly suggest that DNA polymerase slippage was the cause of the original germ-line insertion mutation in this family and that the same mechanism was responsible for its deletion in one of the propositus T cell progenitors, thus leading to reversion mosaicism.

Adult↗
PubMed2001

The regulation of elongation by eukaryotic RNA polymerase II: a recent view.

The elongation of mRNA by RNA polymerase II (RNAPII) is controlled by the diverse actions of cis- and trans-acting elements that respond to a variety of biological signals. Elongation regulation, which determines the processivity of RNAPII, occurs during the steps of transcription initiation and elongation through both negative and positive influences. It has been generally accepted that negative elongation factors repress the elongation reaction. It is also generally accepted that positive elongation factors act by allowing the stalled RNAPII to escape from an inactive state, thus facilitating the production of full-length transcripts. However, recent data suggests that these opposing regulatory mechanisms can be achieved through a coupling pattern, rather than through independent activity. In addition, biochemical experiments using 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB) have identified several factors involved in DRB-sensitive transcription, and elucidated the mechanism of interplay between the positive and negative elongation factors. Here, we will review the major findings from studies on RNAPII elongation control. We will further discuss the properties of newly identified factors that have resulted from studies on the action of DRB on elongation.

RNA Polymerase III↗
PubMed2001

Impaired synergistic activation of stress-activated protein kinase SAPK/JNK in mouse embryonic stem cells lacking SEK1/MKK4: different contribution of SEK2/MKK7 isoforms to the synergistic activation.

Stress-activated protein kinase/c-Jun NH(2)-terminal kinase (SAPK/JNK), which is a member of the mitogen-activated protein kinase (MAPK) family, plays an important role in a stress-induced signaling cascade. SAPK/JNK activation requires the phosphorylation of Thr and Tyr residues in its Thr-Pro-Tyr motif, and SEK1 (MKK4) and MKK7 (SEK2) have been identified as the upstream MAPK kinases. Here we examined the activation and phosphorylation sites of SAPK/JNK and differentiated the contribution of SEK1 and MKK7alpha1, -gamma1, and -gamma2 isoforms to the MAPK activation. In SEK1-deficient mouse embryonic stem cells, stress-induced SAPK/JNK activation was markedly impaired, and this defect was accompanied with a decreased level of the Tyr phosphorylation. Analysis in HeLa cells co-transfected with the two MAPK kinases revealed that the Thr and Tyr of SAPK/JNK were independently phosphorylated in response to heat shock by MKK7gamma1 and SEK1, respectively. However, MKK7alpha1 failed to phosphorylate the Thr of SAPK/JNK unless its Tyr residue was phosphorylated by SEK1. In contrast, MKK7gamma2 had the ability to phosphorylate both Thr and Tyr residues. In all cases, the dual phosphorylation of the Thr and Tyr residues was essentially required for the full activation of SAPK/JNK. These data provide the first evidence that synergistic activation of SAPK/JNK requires both phosphorylation at the Thr and Tyr residues in living cells and that the preference for the Thr and Tyr phosphorylation was different among the members of MAPK kinases.

Animals↗
PubMed2001

Cooperative multipoint recognition of organic dyes by bis(beta-cyclodextrin)s with 2,2'-bipyridine-4,4'-dicarboxy tethers.

A series of novel 6,6'-bis(beta-cyclodextrin)s linked by 2,2'-bipyridine-4,4'-dicarboxy tethers; that is, 2,2'-bipyridine-4,4'-dicarboxy-bridged bis(6-O-beta-cyclodextrin) (2) and N,N'-bis(2-aminoethyl )-2,2'-bipyridine-4,4'-dicarboxamide-bridged (3), N,N'-bis(5-amino-3-azapentyl)-2,2'-bipyridine-4,4'-dicarboxamide-bridged (4) and N,N'-bis(8-amino-3,6-diazaoctyl)-2,2'-bipyridine-4,4'-dicarboxamide-bridged bis(6-amino-6-deoxy-beta-cyclodextrin) (5), has been synthesized as cooperative multipoint-recognition receptor models. The inclusion complexation behavior of 2-5 with organic dyes; that is, ammonium 8-anilino-1-naphthalenesulfonate, Brilliant Green, Methyl Orange, Acridine Red, and Rhodamine B, has been investigated in aqueous phosphate buffer solutions (pH 7.20) at 25 degrees C by means of ultraviolet, fluorescence, and circular dichroism spectrometry as well as by fluorescence lifetime measurements. The spectral titrations gave the complex stability constants (Ks) and Gibbs' free energy changes (deltaG degrees) for the inclusion complexation of 2-5 with the organic dyes and other thermodynamic parameters (deltaH degrees and deltaS degrees) for the inclusion complexation of 2-4 with the fluorescent dyes Acridine Red and Rhodamine B. Bis(beta-cyclodextrin)s 2-5 displayed higher binding abilities toward most of the examined dye molecules than native beta-cyclodextrin 1; this is discussed from the viewpoints of the size/shape-fit concept, the induced-fit interaction, and cooperative, multipoint recognition by the bridging chain and the dual hydrophobic cavities. Thermodynamically, the inclusion complexation of 2-4 with Acridine Red is totally enthalpy driven with a negative or minor positive entropic contribution, but the inclusion complexation with Rhodamine B is mainly entropy-driven with a mostly positive, but occasionally negative, enthalpic contribution; in some cases this determines the complex stability.

Journal Article↗
PubMed2001

Unique fluorescence behavior of rhodamine B upon inclusion complexation with novel bis(beta-cyclodextrin-6-yl) 2,2'-bipyridine-4,4'-dicarboxylate.

Newly synthesized bis(beta-cyclodextrin-6-yl) 2,2'-bipyridine-4,4'-dicarboxylate was found to induce an unusual fluorescence enhancement of Rhodamine B (RhB) upon complexation. This effect is attributable to the equilibium shift of RhB to the highly fluorescent carboxylate ion form, which is induced by the cooperative binding by two appropriately preorganized cyclodextrin units in the bis(beta-cyclodextrin). This sandwich complexation behavior was investigated by means of the fluorescence and 2D NMR spectroscopy.

Cyclodextrins↗
PubMed2001

Stimulation of RNA polymerase II elongation by hepatitis delta antigen.

Transcription elongation by RNA polymerase II (RNAPII) is negatively regulated by the human factors DRB-sensitivity inducing factor (DSIF) and negative elongation factor (NELF). A 66-kilodalton subunit of NELF (NELF-A) shows limited sequence similarity to hepatitis delta antigen (HDAg), the viral protein required for replication of hepatitis delta virus (HDV). The host RNAPII has been implicated in HDV replication, but the detailed mechanism and the role of HDAg in this process are not understood. We show that HDAg binds RNAPII directly and stimulates transcription by displacing NELF and promoting RNAPII elongation. These results suggest that HDAg may regulate RNAPII elongation during both cellular messenger RNA synthesis and HDV RNA replication.

Amino Acid Sequence↗