Biomedical subjects

M Tatebe

Publications and source records attributed to M Tatebe.

7 recordsLinked to original sources

PubMed2005

Results of ulnar shortening osteotomy for ulnocarpal impaction syndrome in wrists with neutral or negative ulnar variance.

Ulnocarpal impaction syndrome was diagnosed in six wrists of five patients with neutral or negative ulnar variance. All underwent ulnar shortening with satisfactory results. The average grip strength increased from 53% to 78% and the range of flexion-extension increased from 82% to 93%, the mean Cooney's score improved from 25 to 83. These cases show that ulnocarpal impaction syndrome can occur in wrists with zero or negative ulnar variance, and that ulnar shortening is an effective treatment for such wrists.

Adult↗

PubMed2005

Bilateral Kienbock's disease.

We conducted a retrospective review of 11 patients with bilateral Kienbock's disease from our series of 251 patients with Kienbock's disease. There were no significant differences in radiographic parameters, including ulnar variance and carpal bone angle, between those with unilateral and those with bilateral Kienbock's disease. None of the patients with bilateral disease had been treated with corticosteroids or had a systemic disease that predisposed to osteonecrosis. Thus, this study failed to demonstrate any risk factor for bilateral, as opposed to unilateral Kienbock's disease.

Adolescent↗

PubMed2005

Differentiation of transplanted mesenchymal stem cells in a large osteochondral defect in rabbit.

BACKGROUND: Although accumulating evidence shows that mesenchymal stem cells (MSC) are a promising cell source for articular cartilage repair, the fate of transplanted MSC has not been extensively studied. METHODS: To monitor their persistence and differentiation, we labeled uninduced MSC with a fluorescent dye, PKH26, and transplanted them, in a poly-glycolic-acid scaffold, to full-thickness defects made in the weight-bearing area of rabbit femoral trochleae with hyaluronate sheets. The fate of the labeled cells was monitored for up to 8 weeks. RESULTS: Two weeks after transplantation, immature cartilage containing collagen type II had formed. By 8 weeks, this cartilage had thinned and immunolabeling for collagen type II gradually disappeared from the basal region, which became positive for collagen type I. Most chondrocytes within the regenerated cartilage were PKH26-positive and, therefore, derived from transplanted MSC, whereas osteoblasts within the regenerated bone were a mixture of donor- and host-derived cells. The thickness of the cartilage became thinner up to 8 weeks and then remained stable up to 42 weeks after surgery. DISCUSSION: These results showed that uninduced MSC were able to survive osteochondral defects and differentiated according to the environment, making a major contribution to initial cartilage formation and a partial contribution to bone regeneration.

Animals↗

PubMed2004

Differences in radiographic findings between scaphoid fracture patterns.

Scaphoid fracture patterns can be divided into volar and dorsal type using three-dimensional computed tomography. Ninety-nine patients underwent this examination plus radiography to determine how often fracture pattern was identifiable by radiography including proximal fragment ratio (PFR) measurement. Oblique radiographs obtained at 45 degrees of pronation demonstrated a volar displacement in 28 of 37 volar type fractures in three-dimensional computed tomography (76%), while as oblique view with 45 degrees of supination could identify the dorsal type in ten of 18 (56%). PFR showed a significant difference, with means of 0.59 for volar type and 0.43 for dorsal type. Using oblique views in the two rotational directions together with the PFR, the two fracture patterns could be differentiated in 35 of 43 fractures (81%). No differences were evident between the two fracture patterns with respect to prevalence of dorsal intercalated segment instability deformity.

Adolescent↗

PubMed1997

Selective multiple labeling strategy to obtain accurate NMR parameters for nucleic acids. Conformational analysis around the glycosidic bond.

A systematic synthesis of pyrimidine nucleosides with 13C-labels only at specific atoms in both the base and sugar moieties has been developed in order to obtain conformational information about the glycosidic bond through measurement of the accurate vicinal coupling constants between H1' and C2/C6. For this purpose, 13C labels at three positions, namely C1', C2, and C6, are essential. We have synthesized selectively multiply labeled nucleosides, such as [2, 1'-13C2]-thymidine, [2, 1'-13C2]-2'-deoxycytidine, [6, 1'-13C2]-thymidine, and [6, 1'-13C2]-2'-deoxycytidine. These nucleosides will be useful to determine the relative orientation of the base and sugar moieties.

Carbon Isotopes↗

PubMed1993

RNA priming coupled with DNA synthesis on natural template by calf thymus DNA polymerase alpha-primase.

A bovine genomic DNA library was surveyed with respect to the template activity for RNA-primed DNA synthesis by calf thymus DNA polymerase alpha-primase complex. About 7% of the single-stranded DNA clones contained distinct initiation sites consisting of pyrimidine clusters of pyrimidine-rich sequences. The initiation sites were located at or near the 3'-end of the pyrimidine clusters. One of these sequences, containing a 10-mer pyrimidine cluster with major initiation sites, was analyzed in detail. By the successive substitutions of pyrimidines in the cluster with oligodeoxydenylate [(dA)n] in the 5' to 3' direction, the minimum length of the initiation sequence was estimated to be as long as the 7-mer. In contrast, when one or three pyrimidines at the 3'-end of the cluster were replaced with (dA)n, the priming activity was largely lost, indicating that these pyrimidine residues were indispensable for priming. Furthermore, base substitutions of upstream or downstream sequences outside the pyrimidine cluster also decreased the total priming frequencies. Interestingly, the base substitutions inside or outside of the pyrimidine cluster sometimes caused a shift in the major priming sites. These results indicate that the minimum priming unit of the CTPPS1 template for RNA-primed DNA synthesis consists of a pyrimidine cluster (6-mer) with one purine at its 3'-border and that both the 3'-downstream 6-bases and the 5'-upstream 17-bases modulate the priming by enhancing the priming frequency and/or slightly shifting the sites of initiation of primer synthesis. It was also revealed that the lengths of the product RNA primers became shorter as the length of pyrimidine cluster was shortened by substitution with (dA)n. The gel retardation assay further showed that the complex formation between DNA polymerase alpha-primase and the DNA templates was strongly in competition with poly(dC), poly(dG), and poly(dT) but not with poly(dA). Furthermore, template activities as well as the pyrimidine contents of a series of base-substituted DNA correlated well with their affinities to the enzyme, as measured by both gel retardation assay and their Km values for the priming reaction. Apparently, DNA polymerase alpha-primase primarily recognizes the minimum priming unit consisting of a pyrimidine cluster with a purine at the 3'-boundary of purine, but the initiation of primer RNA synthesis can be modified by pyrimidine residues outside of the minimum priming unit.

Adenosine Triphosphate↗

PubMed1993

Deoxypyrimidine cluster mediates the priming by calf thymus DNA primase subunit.

Homogeneously purified DNA polymerase alpha subunit-free primase was used to analyze primer RNA synthesis. On a chemically synthesized 36 mer DNA template, a part of upstream region of human c-myc gene, the primer synthesis started from a doublet of deoxythymidine (TT) in the deoxypyrimidine-rich sequence. The primase in DNA polymerase alpha-primase complex synthesized 21-mer reaction product, while DNA polymerase alpha-free primase gave the similar products, 21- and 22-mer, indicating that the site recognition was carried out by primase itself and DNA polymerase alpha subunit has an auxiliary role on it. Product analysis using DNA fragments carrying base substitutions further revealed that the existence of deoxypyrimidine residues around the starting sites was important for priming frequencies. Competition analysis showed that the priming was strongly competed by poly(dC), and to a much lesser extent by poly(dA). Gel-shift analysis showed that the primase could bind to the DNA template, and this complex formation was also competed by poly(dC), but not by poly(dA). These results indicate that primase subunit interacts with the starting site by binding directly with deoxypyrimidine residues.

Animals↗