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Biomedical subjects

K Tsutsui

Publications and source records attributed to K Tsutsui.

262 records · Page 15Linked to original sources
PubMedDate not supplied

Specificity of SAF-A and lamin B binding in vitro correlates with the satellite DNA bending state.

There is evidence that Matrix Attachment Region (MAR)-binding proteins also bind satellite DNA (satDNA). The aim of the current work was to determine whether the major nuclear matrix (NM) MAR-binding proteins are able to recognize satDNAs of different locations and what DNA structural features are important for the recognition. In nuclei and NM, a number of the same polypeptides were recognized on a southwestern blot when MAR of immunoglobulin kappa gene (Ig kappa MAR) and pericentromeric (periCEN) satDNA fragments were used. However, the binding decreased dramatically when human and mouse CEN satDNA were used for the probes. After an NM extract was subjected to ion exchange chromatography, the main DNA-binding proteins were identified as SAF-A (scaffold attachment factor A) and lamin B. It was not possible to test the binding of lamin B by gel mobility shift assay (GMSA), but SAF-A showed an ability to distinguish CEN and periCEN satDNA fragments in GMSA. While periCEN fragments have an abnormally slow mobility on electrophoresis, which is a hallmark of bent DNA, CEN satDNA fragments have a normal mobility. A computer analysis was done using the wedge model (Ulanovsky and Trifonov [1987] Nature 326:720-722), which describes how the curved state depends on particular nucleotide sequences. The curved states of the fragments predicted by the model are in good agreement with their ability to be recognized by NM proteins. Thus SAF-A and lamin B are able to recognize conserved structural features of satDNA in the same way that MAR-binding proteins recognize MARs in spite of a lack of a consensus sequence. CEN and periCEN satDNAs are distinguished by proteins in correlation with the helical curvature of these fragments.

Animals↗
PubMedDate not supplied

A novel approach to high-throughput quality control of parallel synthesis libraries.

Combinatorial chemistry is a powerful tool to enhance drug discovery efforts in the pharmaceutical industry. One type of combinatorial chemistry, parallel synthesis, is now widely used to prepare numerous compounds of structural diversity. A novel high-throughput method for quality control of parallel synthesis libraries has been developed. The method uses flow injection MS, for proof of structure and estimation of purity, and a novel direct injection CLND technique for quantitation of amount. Following the synthesis of a small molecule library, compounds analyzed using this technique were characterized by mass spectrometry, and an accurate concentration of the compound was assessed by CLND. Characterization of one compound is completed in 60 s, allowing for up to 1000 compounds to be analyzed in a single day. The data is summarized using pass/fail criteria using internally developed software.

Chemistry, Organic↗
PubMedDate not supplied

MR imaging of gynecologic lymphoma.

We present a case of solitary secondary gynecologic lymphoma, in which MR imaging contributed to the diagnosis. The finding was a region of uterine enlargement consisting of ill-defined nodules of variable signal intensity diffusely mixed with the myometrium.

Aged↗
PubMedDate not supplied

Involvement of muscle by malignant lymphoma: MR and CT appearances.

OBJECTIVE: The purpose of this study is to investigate the CT and MR findings of muscular involvement by malignant lymphoma and identify the CT and MR features that may assist in their diagnosis. MATERIALS AND METHODS: Magnetic resonance imaging was performed on four patients (five lesions) with pathologically proven non-Hodgkin lymphoma using a 1.5 T unit (Cases 1, 2, and 4) and a 0.5 T scanner (Case 3). Computed tomography scans were carried out on three patients (Cases 1, 3, and 4). RESULTS: The lesions that extended along muscle fascicles with preserved fat planes looking like swelling of the muscle were of slightly hyper- to isointensity relative to uninvolved muscles on T1-weighted images, of hyperintensity on T2-weighted images, and of low or isodensity on CT. Microscopically, lymphoma cells were seen clustering among normal and atrophic muscle fibers in a biopsy specimen of one patient. The lesions enhanced relatively homogeneously after Gd-DTPA injection. In three cases, vessels were coursing through the lesion on MRI and in two cases on enhanced CT. CONCLUSION: Magnetic resonance imaging proved useful to show the extension of involvement of muscular lymphoma compared with CT. The diagnosis of infiltration of muscle by lymphoma is entertained when a lesion of relatively homogeneous intensity and density extends along the muscle fascisles without obliteration of the fat planes and especially when vessels are identified within the lesion.

Aged↗
PubMedDate not supplied

Tumor vessels and contrast enhancement of hepatocellular carcinoma demonstrated by percutaneous transhepatic portography. Report of a case.

A patient with an Edmondson type I-II hepatocellular carcinoma had, at celiac angiography, a poor arterial supply but a rich portal supply as observed at percutaneous transhepatic portography, an observation not previously reported in this disease. The importance of demonstrating the vascular supply of the tumor previous to planned intravascular treatment is obvious.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Transplantation of new autologous biomaterials into jaw cleft.

This study compared bone-marrow grafting using chondroid or fibula bone grafts transplanted into simulated alveolar bone defects in mice. The osteogenic procedure was also investigated. As an experimental model of the maxillary alveolar bone cleft, suitable for testing bone-inductive materials, a surgical trephine with a low-speed dental engine was used to form critical-sized defects in the pre-maxillary bones of male mice. Distraction osteogenesis was performed using an external fixation device. The osteotomy site was surrounded by an external callus, consisting of hyaline cartilage, that contained a large quantity of chondroid bone. Transplanted bone within chondroid bone was characterized by bone formation and remodelling 30 days post-transplantation, and bone adhesion following chondroid bone grafting was better than adhesion following fibula grafting. The present findings are the first to demonstrate the potential of chondroid bone transplantation as a new therapeutic system of bone grafting, suitable for bone substitution in craniofacial bone defects.

Animals↗
PubMedDate not supplied

Amyloid beta protein deposition in osteopetrotic (op/op) mice is reduced by injections of macrophage colony stimulating factor.

The deposition of amyloid beta (Abeta) protein is a neuropathological change that characterizes Alzheimer's disease. Animals with the osteopetrosis (op/op) mutation suffer from a general skeletal sclerosis, a significantly reduced number of macrophages and osteoclasts in various tissues, and have no systemic macrophage colony stimulating factor (M-CSF). This study examined the effect that M-CSF injections had on Abeta deposition and microglial cell distribution in the brains of normal and op/op mice. Abeta-positive plaques were detected in the cerebral cortex of op/op mice, but not in normal mice. M-CSF reduced the numbers of Abeta-positive plaques in op/op mice. The microglial cell population was reduced in op/op mice compared with normal mice, and M-CSF increased the numbers to 65.8% of that observed in normal mice. Our results suggest that a clearer understanding of the role that microglial cells play in Abeta deposition may help determine the mechanisms involved in the pathogenesis of Alzheimer's disease.

Amyloid beta-Peptides↗
PubMedDate not supplied

The tumor-preventing effect of a mixture of several lactic acid bacteria on 1,2-dimethylhydrazine-induced colon carcinogenesis in mice.

The anti-tumor effect of a dietary supplement obtained from mixed cultures of several lactic acid bacteria was examined in the colon of tumor-inducing ICR male mice by use of a carcinogen, 1,2-dimethylhydrazine (DMH, 20 mg/kg body weight, 1 intra-muscular injection per week for 10 weeks). The animals were sacrificed either 15 weeks or 24-26 weeks after the first carcinogen injection. Macroscopically, the incidence of colon tumors at a 24-26 week period of tumor induction was apparently lower in mice treated with both the DMH and dietary supplement (76%) than in those treated with DMH alone (100%). Histologically, microadenomas were induced predominantly in the anal half of the total colon, and large lymphoid aggregates were often associated with dysplastic crypts in the distal colon. Apoptotic cell masses were shed into the distended lumen of the involved crypts. The statistical analysis at a 15-week period of tumor induction indicated that the incidence of microadenomas per tumor-induced mouse was lowered significantly by use of the dietary supplement. From the present results, it is suggested that the intake of the dietary supplement inhibits the early development of colon adenomas, and the inhibition of microadenomas results in a reduction of subsequent polyp and tumor yield in the mouse colon.

1,2-Dimethylhydrazine↗
PubMedDate not supplied

Purification and biochemical characterization of squirrel monkey retrovirus-H produced in a human lymphoblastoid cell line.

We found a type D retrovirus in a human lymphoblastoid cell line of B-cell lineage. Molecular cloning and nucleotide sequencing of the provirus genome revealed that this virus was closely related to squirrel monkey retrovirus (SMRV), and we designated this virus as SMRV-H. To investigate the relationship between these retroviruses, SMRV-H was purified from the virus-producing cells, and its biochemical properties were characterized. The cell-adhesive virus particles were successfully separated from the cell by a brief trypsin treatment and purified by velocity sedimentation. The purification of the virus was confirmed by electron microscopy. Major gag protein of the virus is phosphorylated, and has a molecular weight of 34 kDa. The virion-associated reverse transcriptase prefers Mg2+ to Mn2+. These properties of SMRV-H were almost the same as those of SMRV.

Animals↗