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Biomedical subjects

N Kurata

Publications and source records attributed to N Kurata.

At least 55 records · Page 3Linked to original sources
PubMed1997

Physical mapping of the rice genome with YAC clones.

Construction of a rice physical map covered by YAC clones which have been arranged over half of the genome length is presented here. A total of 1285 RFLP and RAPD markers almost evenly distributed on the rice genetic map could select 2974 YAC clones and 2443 clones of them were located on their original positions. Rice YACs carrying 350 kb average insert fragments of 2443 clones could cover 222 megabase length of the rice genome, corresponding to 52% of the whole genome size (4.3 Mb). Chromosome landing with many YAC clones on the high-density genetic map loci efficiently integrated the genetic map with a physical map. This is the first step to generate a comprehensive genome map of rice. An integrated genome map should be an indispensable tool to figure out genome structure as well as to clone trait genes by map-based cloning.

Chromosome Mapping↗
PubMed1996

Physical mapping of rice chromosomes 8 and 9 with YAC clones.

First efforts for physical mapping of rice chromosomes 8 and 9 were carried out by ordering YAC clones of a rice genomic DNA library covering six genome equivalents with mapped DNA markers. A total of 79 and 74 markers from chromosomes 8 and 9, respectively, were analyzed by YAC colony and Southern hybridization using RFLP markers of cDNA and genomic clones, and by polymerase chain reaction (PCR) screening using PCR-derived and sequence-tagged site (STS) markers. As a result, 252 YAC clones were confirmed to contain the mapped DNA fragments on both chromosomes. A contig map was constructed by ordering these YAC clones and about 53% and 43% genome coverage was obtained for chromosomes 8 and 9, respectively, assuming a YAC clone size of 350 kb and overlap between neighboring YACs of 50%. A continuous array of YAC clones with minimum overlap gave a total size of 18.9 Mb for chromosome 8 and 15.6 Mb for chromosome 9, which are close to previous estimates. These contig maps may provide valuable information that can be useful in understanding chromosome structure and isolating specific genes by map-based cloning.

Blotting, Southern↗
PubMed1996

Assignment of YAC clones spanning rice chromosomes 10 and 12.

Yeast artificial chromosome (YAC) clones were assigned on rice (Oryza saliva L. cv. Nipponbare) chromosomes 10 and 12 using DNA markers from our high-density linkage map. Out of 1,383 markers localized in this genetic map, 68 and 74 markers were located on chromosomes 10 and 12, respectively. Screening of the YAC genomic library was conducted by colony hybridization and Southern hybridization using restriction fragment length polymorphism (RFLP) markers or by polymerase chain reaction (PCR) using sequence-tagged site (STS) markers. We have completed the screening of 68 markers on chromosomes 10 and 74 markers on chromosome 12. A total of 134 and 103 YACs were assigned to chromosomes 10 and 12, respectively, with an estimated coverage of more than 60% for chromosome 10 and about 47% for chromosome 12. As rice is considered a model plant for genome analysis, the ordered YAC clones on chromosomes 10 and 12 as well as other chromosomes will certainly be helpful for isolation of agronomically and biologically important genes and for understanding the genome structure of these chromosomes.

Chromosome Mapping↗
PubMed1996

Physical mapping of rice chromosome 1 with yeast artificial chromosomes (YACs).

We have constructed a physical map of rice chromosome 1 using yeast artificial chromosomes (YACs). A YAC library of 350 kb average insert size, covering about 6 rice haploid genome equivalents, was screened using 182 DNA markers which we had previously located on chromosome 1, by colony hybridization and polymerase chain reaction (PCR) amplification. One hundred and sixty-two DNA markers identified at least one YAC each carrying one, two or more marker sequences, for a total of 476 clones. Of these identified YACs, 284 were located in their original positions on chromosome 1. These 284 YACs defined 69 YAC contigs or islands which are estimated to cover more than 60% of the total chromosome length. The use of mapped DNA markers in constructing a physical map facilitates the integration of genetic and physical maps, as well as fine ordering of the DNA markers, especially at sites where the markers are clustered tightly on the genetic map. Our high density molecular map has been proven, by chromosome landing with YACs using mapped DNA markers, to cover more than half of the entire length of chromosome 1. The remaining 192 YACs were selected by other copies of DNA markers that mapped on chromosome 1. This description of the YAC contigs formed on chromosome 1 constitutes the second report of rice physical mapping, following that for chromosome 6.

Chromosome Mapping↗
PubMed1996

Construction of YAC contigs on rice chromosome 5.

A physical map of rice chromosome 5 was constructed with yeast artificial chromosome (YAC) clones along a high-resolution molecular linkage map carrying 118 DNA markers distributed over 123.7 cM of genomic DNA. YAC clones have been identified by colony and Southern hybridization for 105 restriction fragment length polymorphism (RFLP) markers and by polymerase chain reaction (PCR) screening for 8 sequence-tagged site (STS) markers and 5 randomly amplified polymorphic DNA (RAPD) markers. Of 458 YACs, 235 individual YACs with an average insert length of 350 kb were selected and ordered on chromosome 5 from the YAC library. Forty-eight contigs covering nearly 21 Mb were formed on the chromosome 5; the longest one was 6 cM and covered 1.5 Mb. The length covered with YAC clones corresponded to 62% of the total length, of chromosome 5. There were many multicopy sequences of expressed genes on chromosome 5. The distribution of many copies of these expressed gene sequences was determined by YAC Southern hybridization and is discussed. A physical map with these characteristics provides a powerful tool for elucidation of genome structure and extraction of useful genetic information in rice.

Chromosome Mapping↗
PubMed1996

Evaluating systemic lupus erythematosus disease activity using molecular markers of hemostasis.

OBJECTIVE: To determine the usefulness of measuring sensitive markers of the coagulation-fibrinolysis system (i.e., thrombin-antithrombin III complex [TAT], D dimer fragments [DD], and plasmin-alpha2-plasmin inhibitor complex [PIC]) for evaluating disease activity in patients with systemic lupus erythematosus (SLE). METHODS: We studied 57 SLE patients. Plasma concentrations of DD were measured by latex agglutination using monoclonal antibodies; TAT and PIC were determined by sandwich enzyme-linked immunosorbent assay. Disease activity was determined by using the SLE Disease Activity Index (SLEDAI). RESULTS: Levels of TAT, DD, and PIC were higher in SLE patients than in healthy controls (P<0.05). Levels of TAT and DD showed good correlations with SLEDAI scores (for TAT r=0.66, P<0.001; for DD r=0.50, P<0.001). Elevated levels of TAT, DD, and PIC were decreased following treatment. CONCLUSION: These results strongly suggest that measurement of molecular markers of hemostasis is useful for evaluating disease activity in patients with SLE.

Adult↗
PubMed1996

Pulmonary artery involvement as first manifestation in three cases of Takayasu arteritis.

Although the pulmonary artery is often involved in Takayasu arteritis, only a few cases have been reported in which pulmonary artery involvement occurred as the initial clinical manifestation. Based upon history, physical findings, laboratory data, and radiographic studies, we diagnosed Takayasu arteritis in three young females who had pulmonary artery occlusion without apparent lesions in the aortic arch and its main branches. Major symptoms and signs encountered were persistent mild or moderate chest pain, pleural effusion, and an episode of hemoptysis. Pulmonary artery occlusions were confirmed by angiography and perfusion studies. Steroid treatment relieved the symptoms in two cases, but the 3rd case required additional therapy with methotrexate for the suppression of disease activity. We emphasize the importance of considering Takayasu arteritis in cases with the above-mentioned signs and symptoms and pulmonary artery occlusion, despite the absence of aortic lesions.

Adult↗
PubMed1996

An ordered yeast artificial chromosome library covering over half of rice chromosome 6.

Yeast artificial chromosome (YAC) clones carrying DNA marker sequences located on the rice genetic map of chromosome 6 were ordered for physical mapping. A total of 122 restriction fragment length polymorphism markers, 16 sequence-tagged site markers, and five random amplified polymorphic DNA markers located, on average, at 0.9-cM intervals, were used for YAC clone screening by colony/Southern hybridization and PCR screening, respectively. A total of 216 individual YACs were selected from our YAC library of 7000 clones covering six genome equivalents. Each DNA marker could select, on average, 4.8 YAC clones, with 11 clones being the maximum. The YACs localized to the corresponding linkage map positions form 43 contigs and encompass about 60% of rice chromosome 6. This is the first step in constructing a physical map covering the whole rice genome by chromosome landing with YAC clones. These YACs and data will be used soon to isolate phenotypical trait genes by map-based cloning.

Blotting, Southern↗
PubMed1996

High-affinity anti-DNA antibody parallels clinical course of immunoadsorption therapy for systemic lupus erythematosus.

Anti-DNA antibody, especially high-affinity anti-DNA antibody (ADNA), is thought to have an important role in the pathogenesis of lupus nephritis. In this study, ADNA which binds to double-stranded DNA under a high concentration of sodium chloride was measured in patients who had received immunoadsorption (IA) therapy with a dextran-sulfate column. Titers of high-affinity ADNA in the cases with renal dysfunction tended to be higher than in those without renal dysfunction. The change in the titer of high-affinity ADNA paralleled the clinical course. These findings suggest that measurement of high-affinity ADNA is useful for follow-up of the clinical course of patients who have undergone IA therapy.

Adult↗
PubMed1996

Trimethadione N-demethylation by rat liver CYP2E1 in vitro.

Trimethadione (TMO) is a model drug utilized for estimation of hepatic metabolism in clinical studies, and it was reported that TMO N-demethylase activity was inhibited by CYP2E1 inhibitors and substrates in rat in vivo. This study was performed to investigate the involvement of the CYP2E1 subfamily on TMO N-demethylation in vitro and to clarify these inhibitory mechanisms. The effects of acetone (AC), imidazole (IM) and N-nitrosodimethylamine (NDA) on TMO N-demethylation were studied in vitro. Rat hepatic microsomal fractions were employed as the enzyme source of TMO N-demethylase and the activity was determined by the production of dimethadione (DMO). DMO was analyzed by a GC/FTD equipped with a narrow-bore capillary column. TMO N-demethylation was biphasic by the graphic analysis of Eadie-Hofstee plots; this suggests the involvement of at least two enzymes in TMO metabolism in the rat. The kinetic parameters for the formation of DMO were analyzed graphically using double-reciprocal plots. The apparent K(m1), K(m2) and Vmax1, Vmax2 values for DMO formation were 4, 20 mM and 182, 595 pmol/mg protein/min, respectively. AC and IM inhibited TMO N-demethylase activity competetively. However, mixed inhibition kinetics was observed by NDA. Furthermore, TMO N-demethylase activity was inhibited by antiserum to CYP2E1 by 62% and CYP3A2 by 46%. These results indicate that the CYP2E1 subfamily is the major enzyme involved in TMO N-demethylation in rat in vitro although the CYP3A2 is also involved in this transformation.

Animals↗
PubMed1996

[A successful repair of left ventricular rupture after surgical treatment of ventricular septal perforation complicated due to acute myocardial infarction].

A 75-year-old woman was admitted complaining of anterior chest pains, and peripheral coldness. The 6th day after admission, a loud systolic murmur of Levine IV/VI was audible at the apex. The chest X-ray film demonstrated a cardiomegaly and ST elevation in the V1-V5 leads. UCG and right-heart catheterization revealed an intraventricular shunt from left to right, and the diagnosis of ventricular septal perforation after acute antero-septal myocardial infarction was confirmed. Although, we were continuing and aggressive medical treatment with the intraaortic balloon pumping, an emergency operation for ventricular septal perforation was performed, 15 days after onset. The direct closure of the septal perforation and the plication of the left ventricular free wall with two felt strips were performed. The postoperative course seemed well. But in the 3rd postoperative day, massive bleeding was recognized through the drainage tube. The left ventricular rupture was suggested, and a massive blood transfusion was done. An emergency operation was performed. Another left ventricular free wall was lacerated about 6 mm at the apex. The laceration was closed with teflon felt strips. The patient survived through the operation, and is doing well after 7 years since the operation.

Aged↗
PubMed1995

Conservation of fine-scale DNA marker order in the genomes of rice and the Triticeae.

DNA markers distribute over large chromosomal regions exhibit conservation of order (collinearity) in different cereal species, but it is not known whether this is maintained on a finer scale, i.e. < or = 2 cM. To address this, sets of two or more genetically linked DNA markers were localised to yeast artificial chromosomes containing rice DNA inserts. Linkage analysis of these DNA markers in barley revealed complete correspondence with their genetic order in rice, the distance between linked sequences on rice chromosomes being < 1.6 cM or < or = 1 + 10(6) bp (1 Mb). Thus, DNA markers separated in this range are collinear in rice, barley and, by inference, other members of the Triticeae. These results are discussed with respect to the use of rice as a key system for the isolation of cereal genes.

Base Sequence↗
PubMed1995

Rice-barley synteny and its application to saturation mapping of the barley Rpg1 region.

In order to facilitate the map-based cloning of the barley stem rust resistance gene Rpg1, we have demonstrated a high degree of synteny at a micro level between the telomeric region of barley chromosome 1P and rice chromosome 6. We have also developed and applied a simple and efficient method for selecting useful probes from large insert genomic YAC and cosmid clones. The gene order within the most terminal 6.5 cM of barley chromosome 1P was compared with the most terminal 2.7 cM of rice chromosome 6. Nine rice probes, previously mapped in rice or isolated from YAC or cosmid clones from this region, were mapped in barley. All, except one, were in synteny with the rice gene order. The exception, probe Y617R, was duplicated in barley. One copy was located on a different chromosome and the other in a non-syntenic position on barley chromosome 1P. The barley probes from this region could not be mapped to rice, but two of them were inferred to be in a syntenic location based on their position on a rice YAC. This work demonstrates the utility of applying the results of genetic and physical mapping of the small genome cereal rice to map-based cloning of interesting genes from large genome relatives.

Chromosome Mapping↗
PubMed1995

Genomic organization of 57 ribosomal protein genes in rice (Oryza sativa L.) through RFLP mapping.

Four hundred cDNA clones from rice (Oryza sativa L.) callus and root cDNA libraries, with a high similarity to about 70 kinds of ribosomal proteins (r-protein) in eukaryotic as well as procaryotic organisms, were identified by their deduced amino acid sequences. Southern hybridization of 114 independent cDNA clones with total rice genomic DNA showed 77 distinct and specific hybridization patterns. Of the 77 clones representing the above hybridization patterns, copies of 67 clones corresponding to 57 r-proteins could be estimated and, among these, only 6 clones were single copy, indicating that almost 90% of these r-proteins in rice were encoded by small multigene families. Loci of 36 r-protein genes could be mapped on the rice linkage map by using 30 full-length cDNA clone sequences from specific RELP bands. Another 21 expressed gene loci were mapped using 3' untranslated region specific cDNA probes amplified from the multicopy cDNA clones representing 17 of the r-protein multicopy gene families. The above 57 loci were mapped from 51 cDNA clones and 41 of these r-protein genes mapped to regions that did not show any clustering, while in 5 cases, pairs of r-protein genes cosegregated or linked closely. The r-protein genes in rice were located throughout the 12 chromosomes and it was found that more than one copy within a multigene family may be expressed simultaneously.

Base Sequence↗
PubMed1995

Changes of hepatic microsomal oxidative drug metabolizing enzymes in chronic renal failure (CRF) rats by partial nephrectomy.

Male SD rats, 7-weeks-old, were used to investigate the changes in the hepatic drug metabolizing system of chronic renal failure (CRF) model rats. Partial nephrectomy (5/6) was performed in a two-stage surgical procedure. After nephrectomy, the rats were housed under regular conditions at least 21 days. After confirming the CRF states, trimethadione (TMO, 100 mg/kg, i.p.) was administered for evaluation of the hepatic drug metabolizing capacity; the ratio of dimethadione (DMO: the only metabolite of TMO) to TMO (DMO/TMO) in the serum and the dialysate from the blood microdialysis method were ascertained. The hepatic drug metabolizing enzyme contents and activities were also determined. In the CRF rats, the DMO/TMO ratios decreased significantly; total cytochrome P450 (CYP) contents, aminopyrine N-demethylase activity and delta-aminolevulinic acid synthetase activity also decreased significantly in the CRF rats. The extent of the alterations of these enzyme contents and activities correlated well with the severity of the CRF states evaluated by the serum blood urea nitrogen and creatinine concentrations. With Western blot analysis, the levels of CYP2C6, CYP2C11 and CYP3A2 decreased considerably in the CRF rats. These results suggest that CRF states induce not only a reduction of renal function but also an alteration of hepatic metabolism.

Animals↗
PubMed1995

[A case of Felty's syndrome with marked thrombocytopenia and severe hypocomplementemia].

Felty's syndrome is diagnosed when a patient shows both splenomegaly and leukocytopenia of various degree during the course of rheumatoid arthritis (RA). The accompanying immunologic abnormalities (e.g., antinuclear antibody, antiplatelet antibody, and hypocomplementemia) also characterize Felty's syndrome, but some authors may regard these abnormalities as a transitional form into overlap syndrome [RA + systemic lupus erythematosus (SLE)]. Here we reported a female case of Felty's syndrome who showed marked thrombocytopenia and severe hypocomplementemia. Thrombocytopenia had been refractory against several forms of therapies including high-dose methylprednisolone. Simultaneously, she had various autoantibodies (i.e., antiplatelet antibody, positive Coombs' test, antithyroglobulin antibody, antimicrosome antibody and anti-RNP antibody). Although she did not fulfill the ARA diagnostic criteria for SLE, the degree of thrombocytopenia as well as that of hypocomplementemia argued in favor of the overlap of SLE in this patient. Low-dose cyclosporin A (CsA) combined with small dose of prednisolone could increase both platelet count and level of complement. Notably, the titers of several autoantibodies dropped after CsA was started. These findings might suggest that CsA could normalize the underlying immunologic abnormalities in this patient. However, the disease activity of RA could not be decreased without a help of low-dose methotrexate.

Antirheumatic Agents↗