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Biomedical subjects

K Ogata

Publications and source records attributed to K Ogata.

At least 199 records · Page 11Linked to original sources
PubMed1995

Comparison of the free and DNA-complexed forms of the DNA-binding domain from c-Myb.

The DNA-binding domain of c-Myb consists of three imperfect tandem repeats (R1, R2 and R3). The three repeats have similar overall architectures, each containing a helix-turn-helix variation motif. The three conserved tryptophans in each repeat participate in forming a hydrophobic core. Comparison of the three repeat structures indicated that cavities are found in the hydrophobic core of R2, which is thermally unstable. On complexation with DNA, the orientations of R2 and R3 are fixed by tight binding and their conformations are slightly changed. No significant changes occur in the chemical shifts of R1 consistent with its loose interaction with DNA.

Amino Acid Sequence↗
PubMed1995

Effects of catechins on the mouse tumor cell adhesion to fibronectin.

We studied the effects of 5 kinds of catechins on the adhesion of mouse lung carcinoma 3LL and melanoma B16F10 cells to the fibronectin substratum. (-)-Epicatechin gallate and (-)-epigallocatechin gallate were active in inhibiting the 3LL cell adhesion, while (+)-catechin, (-)-epicatechin, and (-)-epigallocatechin were inactive. Gallate-containing catechins also impaired adhesion and/or spreading of B16F10 cells.

Animals↗
PubMed1995

Interaction of 5SrRNA-L5 protein complex, methionyl-tRNA, and methionyl-tRNA synthetase in the macromolecular ARS complex.

Rat liver cytosol was incubated with a trace amount of rat liver 5SrRNA which was highly labeled at the 3'-end with cytidine 3',5'-[5'-32P]biphosphate, and with [35S]methionine in the presence of ATP mixture, and then with an antibody against ribosomal protein L5. The mixture was analyzed by protein A-Sepharose chromatography. The following results were obtained. (i) The eluate with glycine-HCl buffer (pH 3.0) from the protein A-Sepharose column contained an overlapping peak of 32P- and 35S-radioactivities. In a control experiment using the same amount of 32P-labeled Escherichia coli 5SrRNA with the same specific activity, no fraction of the eluate contained 32P-radioactivity. (ii) The fractions containing both 32P- and 35S-radioactivities from the protein A-Sepharose column were crosslinked by UV irradiation. The products was subjected to PAGE, and RNA in each gel slice was eluted and purified. The fraction containing both 32P- and 35S-radioactivities was present in a region of somewhat higher molecular weight than that of 5SRNP, whereas very low 32P- and 35S-radioactivities were present in this region in the control experiment without UV irradiation. This finding suggested that [35S]methionyl-tRNA interacted with 32P-labeled 5SRNP. (iii) The fraction containing overlapping 32P- and 35S-radioactivities described above was subjected to Sephadex G-150 chromatography. The component containing both radioactivities was distributed in the region corresponding to molecular weights of 10,000 to 250,000 with a peak at about 200,000, suggesting the presence of a complex containing Met-RS (Mr 108,000), 5SRNP (Mr 74,000), and methionyl-tRNA (Mr 25,000). Furthermore, this fraction showed definite Met-RS activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acyl-tRNA Synthetases↗
PubMed1995

Effects of interleukin-12 on natural killer cell cytotoxicity and the production of interferon-gamma and tumour necrosis factor-alpha in patients with myelodysplastic syndromes.

The effects of interleukin 12 (IL-12) on natural killer (NK) cell cytotoxicity and on the production of interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) were examined in 15 patients with myelodysplastic syndromes (MDS), which are well known to have immunologic defects, and in 11 normal subjects. The NK cell cytotoxicity of all of the normal subjects was augmented by incubation with IL-12 alone, and co-incubation with interleukin 2 (IL-2) further augmented it (type A response). The MDS patients showed varied responses to IL-12/IL-2. Seven patients showed the type A response, resulting in augmented NK cell cytotoxicity which was similar to that in the normal subjects. In five other patients the cytotoxicity was not increased by IL-12 alone, but the combination of IL-12 and IL-2 did augment the cytotoxicity (type B response). The augmented cytotoxicity in these type B patients was lower than that in the normal subjects. In the final three MDS patients the cytotoxicity was low and not affected by IL-12 and/or IL-2 (type C response). All patients with refractory anaemia with excess blasts (RAEB) and patients with RAEB in transformation showed a type B or C response. Conversely, six of eight refractory anaemia patients showed a type A response. In MDS patients there was a positive correlation between the percentage of CD3- CD56+ cells in pre-incubated cells and the cytotoxicity of cells incubated with IL-12/IL-2. The combination of IL-12 and IL-2 augmented IFN-gamma and TNF-alpha production by nonadherent mononuclear cells in a synergistic or cumulative manner, respectively, in most patients. These results suggest that IL-12, alone or with IL-2, may modulate these important immunologic functions in most MDS patients.

Adult↗
PubMed1995

Centre and magnitude of vertical forces in complete denture wearers.

The aim of this study was to examine the centre and magnitude of a vertical component of occlusal forces in complete denture wearers during several activities using a newly developed method. A lower complete denture was divided into upper and lower parts parallel to the occlusal plane. They were connected by four force transducers which were embedded in the first premolar and the second molar portions on both sides of the denture base. Forces were recorded during tapping, chewing peanuts and raisins, and clenching. The centre and the magnitude of the forces were calculated from forces recorded by the four transducers. The maximum error of the centre was 1 mm, and the maximum error of the magnitude was 4%. The centre was observed between a first molar and the middle of the edentulous dental arch. Maximal mean value of the forces during chewing was 65-110 N.

Aged↗
PubMed1995

Giant cell tumors of tendon sheath: a single and multiple immunostaining analysis.

Nineteen giant cell tumors of tendon sheath (GCTTS) were studied to elucidate the origin of the proliferating cells of these tumors, using single and multiple immunostaining techniques with a labeled avidin-biotin [LAB] method in paraffin-embedded tissues. Proliferating cell nuclear antigen (PCNA) and Ki-67 (MIB-1) antigen were present in mononuclear cells (PCNA 26%; MIB-14%) but were absent in giant cells. These findings indicate that mononuclear cells, but not giant cells, participate in the proliferative compartment of GCTTS. A histiocytic marker, HAM56, was positive in many mononuclear cells (mean 81%), but was totally negative in osteoclastic giant cells. Another histiocytic antigen, CD68, was expressed in both mononuclear cells (mean 28%) and most of the giant cells (mean 89%). By triple immunostaining for PCNA, HAM56 and vimentin, 83% of PCNA-positive mononuclear cells co-expressed HAM56. Because of the frequent co-expression of PCNA and HAM56, the main portion of proliferating cells in GCTTS may represent a monocyte/macrophage lineage. However, there is a small but definite mesenchymal/fibroblastic component, characterized by PCNA+vimentin+HAM56-, relating to the proliferative compartment of GCTTS. Multiple immunostainings with MIB-1 showed similar patterns to those with PCNA. These observations indicate that the GCTTS represent bimodal proliferative lesions consisting of histiocytic and mesenchymal/fibroblastic elements.

Adolescent↗
PubMed1995

Effects of interleukin-1 and tumor necrosis factor on megakaryocytopoiesis: mechanism of reactive thrombocytosis.

We studied the effects of interleukin-1 (IL-1) and tumor necrosis factor (TNF) on mouse megakaryocytopoiesis to evaluate the role of these cytokines in reactive thrombocytosis associated with inflammation. Injections of IL-1 or TNF to mice induced a significant increase in the megakaryocyte progenitor cell (CFU-Meg) count in the spleen. When IL-1 and TNF were injected simultaneously, the splenic CFU-Meg count was remarkably increased compared with mice injected with either IL-1 (p < 0.003) or TNF (p < 0.001) alone. On the other hand, neither IL-1 nor TNF showed any megakaryocyte-potentiating or -stimulating effects in vitro. In the sera obtained 4 h after administration of IL-1, TNF or both, high megakaryocyte potentiating activities were found. Furthermore, an extremely high level of IL-6 was detected in the serum after administration of both IL-1 and TNF. These results strongly suggest that IL-1 and TNF stimulate megakaryocytopoiesis indirectly via other cytokine(s) induced from accessory cells, and that increased levels of IL-1 and TNF play important roles in the development of reactive thrombocytosis caused by inflammation.

Animals↗
PubMed1995

Interleukin-2 therapy for myelodysplastic syndrome: does it work?

Recent clinical studies suggested that interleukin-2 (IL-2) has therapeutic potential for some hematologic malignancies, but the therapeutic role of IL-2 for myelodysplastic syndrome (MDS) is still unclear. MDS is a clonal malignant disorder which often involves a variety of immunologic abnormalities. Examination of the effects of IL-2 on MDS in vitro yielded the following results: (1) IL-2 did not induce the proliferation of blasts in most MDS cases. (2) The cytotoxicity of IL-2-induced lymphokine-activated killer (LAK) cells for cell lines and MDS blasts was reduced in the high-risk MDS group (refractory anemia with excess blasts (RAEB), RAEB in transformation and MDS transformed to acute leukemia), but it was still preserved in the low-risk MDS group (refractory anemia (RA) and RA with ringed sideroblasts). However, considerable variation in LAK cell cytotoxicity was noted in each group. (3) The reduced LAK cell cytotoxicity observed in MDS was explained, at least in part, by the presence of a reduced of number of natural killer (NK) cells amongst the LAK cells. (4) MDS patients who have a high blood soluble IL-2 receptor (sIL-2R) level often had defects in NK and CD8+ T cells. These in vitro findings suggest that the response to IL-2 is heterogeneous in MDS patients, and those who have a low-risk MDS subtype and/or a low blood sIL-2R level, may be prone to respond to IL-2 therapy. Clinical trials are mandatory in order to elucidate the efficacy of IL-2 therapy in the treatment of MDS.

Anemia, Refractory↗
PubMed1995

A new method for the relief of adult phimosis.

Infantile circumcision is not ordinarily performed in Japan. Adult circumcision causes esthetic problems with scarring and color change, especially in Asian patients. We report our experience with 10 adults who underwent a new method of surgery for correction of phimosis via a longitudinal incision of the prepuce along the constricted area ventrally to release constriction, followed by transverse closure of the wound; removal of excess skin by pinching at the dorsal root of the penis, incising circumferentially except for 2 cm. of ventral skin, and closing the dorsal wound. Functional results in all cases were satisfactory and preputial constriction was fully relieved. Cosmetic results were superior to those of conventional circumcision and dorsal slit methods of adult circumcision because contrasting coloration was obscured behind pubic hair and scarring was coincidental with or beneath the pubic hairline.

Adolescent↗
PubMed1995

[The glutamic acid decarboxylase (GAD) antibodies and their clinical significance].

Since it was reported that the 64kD antigen that had been found to be the target of autoantibodies in the sera from IDDM patients was the same as GAD, GAD antibodies have been one of the focuses of many investigations. In this study, we developed a sensitive radioimmunoassay (RIA) system for GAD antibodies in human sera using native GAD purified from the pig brain. To confirm the relevance of pig GAD as the target antigen, we compared the sequences and antigenic activities among pig, rat and recombinant human GAD65. Based on the data from our and other laboratories, the homology of amino acid sequences between pig and human GAD65 was 96.4%. The coefficient of correlation between the results of human and pig GAD RIA was 0.948. The GAD antibody study group confirmed the clinical usefulness of GAD antibodies not only for the diagnosis of IDDM but also slowly progressive IDDM.

Animals↗
PubMed1995

Identification of human skeletal remains with a mandibular static bone cavity by comparison between ante- and post-mortem dental orthopantomograms: a case report.

We report a case of human skeletal remains in which a mandibular static bone cavity noted in a dental orthopantomogram assisted the positive identification. Unknown totally skeletonized human remains were found on a bushy slope of a hill. In the pockets of the clothing, there were a wooden seal, on which a family name was inscribed, and two cigarette lighters bearing the name of a bank. The body was identified as a male, about 50 years old. The estimated time elapsed since death was about six months to one year. No evidence of trauma was found in the clothing and the bones. The possible cause of death was due to poisoning from ingestion of bromvalerylurea (hypnotics). From the family name inscribed on the seal and the name of a bank on the cigarette lighters, the police investigation caught a missing man of 46 years old, who had last been seen alive about 6 months before. A dental orthopantomogram taken about 2 years before his disappearance was available for comparison. Eighteen days after recovery positive identification was practically accomplished based on unique features of the dental findings and a fairly rare, mandibular static bone cavity (a kind of bone cysts) by a X-ray comparison.

Bone Cysts↗
PubMed1995

Computer graphics of center of masticatory forces in complete dentures.

1. INTRODUCTION. In dental education, it is valuable to show visually the differences between a good-fitting and an ill-fitting complete denture. A vector of masticatory forces across all the teeth of the denture is available to estimate the capability of the denture. The vector is simple while the forces exerted on a denture are very complex. A vector has only two factors, the point of application (center of force) and the magnitude. Because a complete denture acts as a unit, we can obtain the vector from electrical signals detected by transducers installed in the denture base. The aim of this study was to develop software which is able to show visually to dental students, the differences between the vectors of the dentures of three representative complete denture wearers. 2. METHODS. Three subjects, each with either a good, a moderate or an ill-fitting complete denture, were selected. Subject 1 could use the denture very comfortably during experiment. Subject 2 was uncomfortable at the insertion of the new denture, but after adaptations to the denture he could use it very well. Subject 3 had been uncomfortable during the experiment. A bottom complete denture was divided into upper and lower parts. These were connected by the four force-detecting units which were embedded in approximately the first premolar and second molar regions on both sides of the denture. The electric signals from these units during the chewing of peanuts and raisins (sampling time period: 30 msec) were recorded as digital signals and processed using the computer (Macintosh IIcx, Apple Computer) with the A/D converter (Lab-NB), National Instruments). Center and magnitudes of masticatory force were calculated from all sampling points using our newly developed software scripted by ¿C¿ (MPW C, Apple Computer). On the other hand, a tracing of the external shape of the dentition of the denture was made using the project (V-12, NIKON). The tracing of the dentition, with center and magnitude of masticatory forces was displayed successively on the screen like a movie. 3. RESULTS AND DISCUSSION. The typical scenes in each cases during one stroke of chewing were illustrated in Figure 1. The center of each circle is the point of application of the vector and the diameter of the circle is its magnitude. As time proceeded, the diameter of the circle became larger. As the period of denture insertion proceeded, the center of masticatory force was localized on the first molar region in subject 1, was shifted from the middle of the dental arch to the molar in subject 2, and was irregularly moved on the middle of the dental arch in subject 3. This software could visualize the center of masticatory force as an indicator of the type of fitting of the complete denture on display.

Bite Force↗
PubMed1995

Investigation of Culicoides (Diptera: Ceratopogonidae) in relation to the transmission of bovine Onchocerca and other filariae in central Kyushu, Japan.

In Kyushu, Japan, where a human case of zoonotic onchocerciasis was found, a survey was conducted to know if the bovine Onchocerca species of this region, O. gutturosa, O. lienalis and O. sp., which develop in local Simulium spp., were also transmitted by Culicoides. A total of 17,006 out of 42,582 females of eight Culicoides species captured by light-traps from May to November in 1989 and 1990 at two cattle sheds, one in Oita and one in Kumamoto, were dissected and examine for Onchocerca infection. Overall results showed that none of the species had filarial infections except 4 of 946 C. arakawae, an ornithophilic species, collected in Oita which harboured filarial larvae with a short tail, belonging to Lemdaninae. Unsheathed microfilariae indistinguishable from O. lienalis or O. gutturosa were found in the midgut of only one blood-fed C. matsuzawai collected in Oita. It is concluded that Culicoides species would not be vectors of these three bovine Onchocerca species. Additional collections of Culicoides in a residential area of Oita showed that several filarial species, Lemdaninae and Splendidofilarinae, probably from birds, are transmitted by C. arakawae.

Animals↗
PubMed1994

Solution structure of a specific DNA complex of the Myb DNA-binding domain with cooperative recognition helices.

The DNA-binding region of Myb consists of three imperfect tandem repeats (R1, R2, and R3). We have determined the solution structure of a specific DNA complex of the minimum DNA-binding domain (R2R3) by heteronuclear multidimensional NMR. Both R2 and R3 contain three helices, and the third helix in each is found to be a recognition helix. R2 and R3 are closely packed in the major groove, so that the two recognition helices contact each other directly to bind to the specific base sequence, AACNG cooperatively; this is a significant arrangement of recognition helices. The three key base pairs in this sequence are specifically recognized by Asn-183 (R3), Lys-182 (R3), and Lys-128 (R2). In contrast, R1 has no specific interactions with DNA from our NMR study of the DNA complex of the full DNA-binding domain (R1R2R3).

Amino Acid Sequence↗
PubMed1994

Presence of role of the 5SrRNA-L5 protein complex (5SRNP) in the threonyl- and histidyl-tRNA synthetase complex in rat liver cytosol.

A complex containing Thr-RS and His-RS was purified about 1000 to 2000-fold from rat liver cytosol by successive column chromatographies on Sephadex G-200, Phenyl-Sepharose CL-4B, and tRNA-Sepharose. The ratio of the specific activity of Thr-RS and His-RS was relatively constant throughout the purification steps, suggesting that the two synthetases were co-purified as a complex. Chromatographic analyses of the tRNA-Sepharose fraction by Sephadex G-150 column chromatography showed the presence of a hybrid form of the Thr-RS monomer and the His-RS monomer in addition to dimer forms of both enzymes from the pattern of activity of both enzymes. The monomer form of Thr-RS showed high activity comparable to the dimer form and the monomer form of His-RS showed definite activity. An association form of Thr-RS and His-RS dimers was detected by Sephadex G-200 chromatography of rat liver cytosol. Northern blot analysis of RNA prepared from the tRNA-Sepharose fraction showed the presence of 55SrRNA blot analysis of the tRNA-Sepharose fraction using an antibody against ribosomal protein L5, showed the presence of ribosomal protein L5 in this fraction. These findings suggest that the presence of a 5SRNA-L5 protein complex (5SRNP) in the Thr-RS and His-RS complex. 5SRNP enhanced the activity of Thr-RS in a freshly prepared tRNA-Sepharose fraction. It also enhanced the activity of the rat liver cytosol for the attachment of [3H]threonine to endogenous tRNA. This activity was inhibited by an antibody against protein L5, and the inhibition was reversed by addition of 5SRNP. These results indicate that 5SRNP plays a role as a positive effector of Thr-RS in the complex.

Animals↗