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M Ohki

Publications and source records attributed to M Ohki.

At least 19 recordsLinked to original sources
PubMed1996

A yeast artificial chromosome contig and NotI restriction map that spans the tumor suppressor gene(s) locus, 11q22.2-q23.3.

Human chromosome 11q22-q23 is a pathologically important region in which a high level of loss of heterozygosity has been reported for breast, ovary, cervical, colon, and lung carcinomas, malignant melanomas, and hematologic malignancies. This strongly indicates that one or more tumor suppressor genes reside within the deleted region. In this report, we report the development of a contig map that covers most of the deleted regions found in these malignancies. The map comprises a contig of 66 overlapping yeast artificial chromosomes (YACs) and spans a region of 17 Mb from the PGR gene at 11q22.2 to the MLL gene at q23.3. In the process of screening the YACs, 50 new sequence-tagged site markers were developed from the termini of the YAC inserts. These markers were used for chromosome walking, and the data were then integrated into the contig map. NotI restriction mapping of these YACs revealed the presence of at least 26 NotI sites in the region. Using 22 of them, a NotI restriction map of the region from PGR to D11S939 was developed. This YAC contig will provide efficient tools for identification of the putative tumor suppressor gene(s).

Base Sequence↗
PubMed1996

Identification of a novel human gene containing the tetratricopeptide repeat domain from the Down syndrome region of chromosome 21.

The Down syndrome (DS) region on chromosome 21, which is responsible for the DS main features, has been defined by analysis of DS patients with partial trisomy 21. Within the DS region, we constructed a 1.6-Mb P1 contig map previously. To isolate gene fragments from the 1.6-Mb region, we performed direct cDNA library screening and exon trapping using the P1 clones and a human fetal brain cDNA library, and obtained 67 cDNA fragments and 52 possible exons. Among them, 23 cDNA fragments and 4 exons were interpreted to be derived from a single gene by localization on P1 clones and by Northern analysis. To obtain the full-length cDNA sequence, longer cDNA clones were further screened from another human cDNA library which was enriched with longer cDNA species. These clones were sequenced and assembled to a sequence of 9045 bp. This transcribed sequence encodes a novel 2025 amino-acid protein containing tetratricopeptide repeat (TPR) motifs and therefore the gene was designated as TPRD (a gene containing the TPR motifs on the Down syndrome region). The TPR domain has been found in a certain protein phosphatase and in other proteins involved in the regulation of RNA synthesis or mitosis. The TPRD gene, the novel gene which was proved to be in the 1.6-Mb region and to have the interesting features described above, is a candidate for genes responsible for the DS phenotypes.

Amino Acid Sequence↗
PubMed1996

Texture analysis of sonographic features of the parotid gland in Sjögren's syndrome.

OBJECTIVE: The purpose of this study was to develop a method for quantitative analysis of the sonographic features of parotid glands as a noninvasive tool for the diagnosis of Sjögren's syndrome. SUBJECTS AND METHODS: Sonographic texture analyses were performed on the parotid glands of 44 patients with Sjögren's syndrome, 83 healthy volunteers, and 17 patients with chronic parotitis, using a fast Fourier transform program. RESULTS: Texture analysis of sonographic studies of the parotid gland using a Fourier transform showed that the sum of the normalized radial power spectrum in the low-spatial-frequency region (S value) of the parotid gland was significantly higher (p < .0001) in the patients with definite Sjögren's syndrome [6.70 +/- 2.13 (x10(5))] than in the 72 age-matched normal volunteers [3.25 +/- 1.08 (x10(5))]. However, patients with probable Sjögren's syndrome showed S values [3.92 +/- 1.88 (x10(5))] similar to those of the controls. On the other hand, SDs of the echo levels in the parotid gland showed significantly greater (p < .0001) values in patients with definite (4.63 1.07) and probable (4.53 1.47) Sjögren's syndrome than in the normal controls (3.30 0.76). Discriminant analysis showed that a combination of these two distinctive values increased diagnostic accuracy to 96.9%. Furthermore, S values and SDs correlated well with the qualitative grading of sonographic features and with the gradings of sialography. CONCLUSION: The system we describe for texture analysis of sonographic images is useful in the diagnosis of Sjögren's syndrome.

Adult↗
PubMed1996

MR imaging of the parotid gland in Sjögren's syndrome: a proposal for new diagnostic criteria.

OBJECTIVE: Because classic diagnostic techniques for sjögren's syndrome (SS) are invasive and require radiation exposure, a noninvasive diagnostic method might benefit patients with SS. The purpose of this study was to determine whether quantitative analysis of MR images of the parotid gland can differentiate patients with SS from normal subjects. SUBJECTS AND METHODS: We performed quantitative analysis of MR images of the parotid gland for 40 patients with definite and probable SS, for 30 normal subjects matched by age and sex to the SS patients, and for 10 patients with parotid inflammation. MR images of teh parotid gland were assessed by calculating standard deviations (SD) of signal intensity. RESULTS: SD of signal intensity exclusively (p < .0001) separated MR images of the parotid glands of patients with definite SS from those of normal subjects. SD of signal intensity for the parotid glands of patients with probable SS also were significantly higher (p < .001) than those of normal subjects. Changes in signal intensity were specific for SS and did not occur with parotid inflammation. Tentative categorization on the basis of signal intensity patterns on MR images of the parotid glands of SS patients showed a high correlation with the results of labial gland biopsy (r = .834) and sialography (r = .936). CONCLUSION: Taken together, these results conclusively indicate that quantitative analysis of MR images for SD of signal intensity is useful method for diagnosing SS and can replace classic methods, which are invasive.

Adolescent↗
PubMed1995

Assignment of the E4TF1-60 gene to human chromosome 21q21.2-q21.3.

The gene encoding human transcription factor E4TF1-60 was previously mapped to chromosome 21q21. We analyzed the localization of the E4TF1-60 gene in more detail by genomic Southern hybridization and determined the sequence of the exons and the regions surrounding the intron boundaries. We report here that E4TF1-60 locates in the long arm of chromosome 21 at q21.2-q21.3 and contains a total of ten exons.

Chromosomes, Artificial, Yeast↗
PubMed1995

Localization of cDNAs to a region poorly represented in the CEPH chromosome 21 YAC contig: candidate genes for genetic diseases mapped to 21q22.3.

Fifty-three cDNA fragments previously obtained by hybridization selection from random clones in the chromosome 21 cosmid library LL21CNO2 failed to identify clones in the chromosome 21 YAC contig described by Chumakov et al. (1992, Nature 359: 380-387). Using an expanded panel of somatic cell hybrids, we have verified that the majority of these cDNAs map to chromosome 21 and that in particular a very high proportion, approximately 85%, localize to a 5-Mb region of distal 21q22.3. Pulsed-field analysis coupled with information from the NotI restriction map of the region further indicate that 17 cDNA fragments map within 650 kb of the PFKL gene and thus may be candidates for genetic diseases linked to this gene. This work helps to characterize a region poorly represented in the CEPH YAC contig and adds to the number of cDNAs useful in analysis of chromosome 21-associated diseases.

Animals↗
PubMed1995

EWS-FLI-1 and EWS-ERG chimeric mRNAs in Ewing's sarcoma and primitive neuroectodermal tumor.

The t(11;22)(q24;q12) and t(21;22)(q22;q12) are specific chromosomal translocations found in the Ewing family of tumors including ES, PNET and Askin tumors. In these translocations, the amino-terminal portion of the EWS gene located in 22q12 fuses to the carboxyl-terminal portion of the FLI-1 gene located in 11q24 or the ERG gene located in 21q22, which belong to the ets oncogene superfamily of transcription activators. We investigated the chimeric mRNAs of 15 ESs (7 cell lines and 8 tumor samples) and 7 PNETs (3 cell lines and 4 tumor samples) using the RT-PCR method and sequencing. We detected 2 types of EWS-ERG chimeric mRNA in 2 ES cell lines and 1 PNET tumor sample in addition to 4 types of EWS-FLI-1 chimeric mRNA in 11 ESs (4 cell lines and 7 tumor samples) and 4 PNETs (2 cell lines and 2 tumor samples). There seemed to be no association between the type of chimeric mRNA and clinical features such as sex, age, primary site and histopathology of the patients. All of the chimeric mRNAs are generated from in-frame junctions and are thought to encode fusion proteins that may be the molecular mechanism involved in the Ewing family of tumors.

Adolescent↗
PubMed1995

Cloning and gene mapping of the mouse homologue of the CBFA2T1 gene associated with human acute myeloid leukemia.

The human CBFA2T1 (also known as MTG8) gene, on chromosome 8, has been identified through its involvement in the t(8;21) chromosomal translocation, frequently found in acute myeloid leukemia. We report here the isolation and characterization of the mouse homologue of the CBFA2T1 gene, Cbfa2t1h. Nucleotide sequence analysis of Cbfa2t1h cDNA clones revealed an open reading frame encoding a protein of 577 amino acids with an extremely high degree of amino acid identity (99.3%) to the human protein. The nucleotide sequence is also highly conserved between mouse and human in the 5'- and 3'-untranslated regions (87.0, 92.0, and 93.7% identities for 5'-untranslated, coding, 3'-untranslated regions, respectively). The 3'-untranslated region of Cbfa2t1h contains a (CA)n dinucleotide repeat, and the polymerase chain reaction amplification of the (CA)n repeat region revealed fragment length polymorphism among mouse strains. Using this polymorphism, we have mapped Cbfa2t1h to mouse chromosome 4 close to the centromere using SMXA recombinant inbred strains and 106 intersubspecific backcross progenies of the (DBA/2 x Mae) x Mae cross. The chromosomal location was also confirmed by fluorescence in situ hybridization.

Acute Disease↗
PubMed1995

Alternative splicing and genomic structure of the AML1 gene involved in acute myeloid leukemia.

We previously isolated the AML1 gene, which is rearranged by the t(8;21) translocation in acute myeloid leukemia. The AML1 gene is highly homologous to the Drosophila segmentation gene runt and the mouse transcription factor PEBP2 alpha subunit gene. This region of homology, called the Runt domain, is responsible for DNA-binding and protein--protein interaction. In this study, we isolated and characterized various forms of AML1 cDNAs which reflect a complex pattern of mRNA species. Analysis of these cDNAs has led to the identification of two distinct AML1 proteins, designated AML1b (453 amino acids) and AML1c (480 amino acids), which differ markedly from the previously reported AML1a (250 amino acids) with regard to their C-terminal regions, although all three contain the Runt domain. The large C-terminal region common to AML1b and AML1c is suggested to be a transcriptional activation domain. AML1c differs from AML1b by only 32 amino acids in the N-terminal. Characterization of the genomic structure revealed that the AML1 gene consists of nine exons and spans > 150 kb of genomic DNA. Northern blot analysis demonstrated the presence of six major transcripts, encoding AML1b or AML1c, which can all be explained by the existence of two promoters, alternative splicing and differential usage of three polyadenylation sites. A minor transcript encoding AML1a which results from alternative splicing of a separate exon can be detected only by reverse transcription-polymerase chain reaction amplification. The distinct proteins encoded by the AML1 gene may have different functions, which could contribute to regulating cell growth and/or differentiation through transcriptional regulation of a specific subset of target genes.

Alternative Splicing↗
PubMed1995

Relation of early menarche to high bone mineral density.

The study of background factors in individuals with high bone mineral density (BMD) may provide useful information in the prevention of osteoporosis. We investigated the relationship of reproductive factors to BMD. In 519 female volunteers (327 postmenopausal and 192 premenopausal women) ranging in age from 21 to 74 (mean 52.3 +/- 11.8) years, spinal BMD values were obtained using both quantitative computed tomography and dual x-ray absorptiometry. The z score was calculated from the mean BMD in each 5-year age group, and high BMD and low BMD was defined as BMD with z score > + 1.5 and < -1.5, respectively. Normal BMD was defined as BMD within the range - 1.0 < z score < +1.0. Long reproductive period, early menarche, and late menopause were associated with high BMD. Among these, the reproductive period showed the strongest association with BMD. In postmenopausal women, early menopause had a significant relationship with low BMD, and early menarche also had some relation to high BMD. In premenopausal women, there was a significant relationship between early menarche and high BMD. The age at menarche may have a strong association with peak bone mass, as suggested by the positive correlation of early menarche with high BMD observed in this study. It is considered important to prevent risk factors that disturb the beginning of menstruation in adolescent girls.

Absorptiometry, Photon↗
PubMed1995

YAC analysis and minimal tiling path construction for chromosome 21q.

We have undertaken a detailed analysis of several hundred YACs from widely available YAC libraries which map to human chromosome 21 with the goal of improving the physical map of chromosome 21 and determining the feasibility of producing a minimal tiling path of well characterized, stable, non-chimeric YACs spanning the long arm of the chromosome (21q). We report information on over 500 YACs known to contain STS from 21q including information on size, stability, chimerism, marker content, and NotI restriction sites. YACs derive from the CEPH and St. Louis YAC libraries, and STSs include the set of 198 markers originally used do assemble a YAC contig of 21q, as well as additional anonymous probes and gene markers. This information has assisted in refinements of STS order, has defined a region of general instability in 2lq22.3, has identified an increased number of NotI restriction sites, and has defined cryptic gaps, particularly in 2lq2l, for which few or no markers are available. These results have allowed us to develop and assess a minimal tiling path of overlapping YACs consisting of 59 YACs (and two PI clones), largely non chimeric, stable, and of verified STS content. They total 30 mb of non-overlapping DNA, and contain all chromosome 21 specific STSs originally used to define the 810 YAC 21q YAC contig. When integrated with the analysis of a somatic cell hybrid mapping panel of chromosome 21 reported in the accompanying manuscript, a greatly enhanced understanding of the physical map of chromosome 21 is obtained.

Chromosome Mapping↗
PubMed1995

Disappearance of AML1-MTG8(ETO) fusion transcript in acute myeloid leukaemia patients with t(8;21) in long-term remission.

In a study of 23 patients with t(8;21)-associated acute myeloid leukaemia the AML1-MTG8 fusion transcript was present in the majority of serial samples obtained from 17 patients followed for up to 34 months after diagnosis, but was absent in samples from all six patients who had been in continuous complete remission for 61 months after allogeneic bone marrow transplantation (BMT), or for 52, 53, 123, 182 and 198 months, respectively, after courses of intensive chemotherapy. Previous studies showed that the AML1-MTG8 fusion transcript was present in most patients with this type of translocation in long-term remission. Our results indicate that blood cells of patients with t(8;21) in remission of over 10 years may not show the AML1-MTG8 fusion transcript, and that those of patients who have undergone allogeneic BMT or intensive chemotherapy may become fusion transcript-negative much earlier. Our study suggests that leukaemic cells with the AML1-MTG8 fusion transcript may survive for some time after courses of chemotherapy or BMT, but that they may eventually be eradicated by immunologic and other antileukaemic mechanisms.

Acute Disease↗
PubMed1995

Trabecular texture analysis of CT images in the relationship with spinal fracture.

PURPOSE: To evaluate age-related changes in trabecular texture and bone mineral density (BMD) and to determine the usefulness of texture analysis in the assessment of the risk of fracture. MATERIALS AND METHODS: The vertebral trabecular BMD was measured in 209 women aged 18-86 years. Run length analysis was applied to computed tomographic images obtained with 2-mm section thickness. The width of the trabecula (T-texture) and the width of the intertrabecular space (I-texture) were calculated. RESULTS: I-texture significantly increased with age in women 50 years of age or older (P < .0001). Women with fracture had significantly lower BMD (P < .0001 at 60-69 years, P < .05 at 70-79 years) and significantly higher I-texture (P < .05 at 60-69 years, P < .01 at 70-79 years). For fracture risk, BMD had the highest sensitivity and I-texture had the highest specificity in women aged 60-69 years; I-texture had the highest sensitivity and specificity in women aged 70-79 years. CONCLUSION: Texture analysis was helpful in the assessment of fracture risk, especially in elderly women.

Adolescent↗
PubMed1994

An RNA-binding protein gene, TLS/FUS, is fused to ERG in human myeloid leukemia with t(16;21) chromosomal translocation.

The t(16;21)(p11;q22) translocation is a recurrent chromosomal abnormality found in several types of myeloid leukemia. We have previously demonstrated that the breakpoints of this translocation are clustered in a specific intron of the ERG gene on chromosome 21, which has recently been reported to be involved in Ewing's sarcoma. We show here that the TLS/FUS gene on chromosome 16 is fused with the ERG gene to produce the TLS/FUS-ERG chimeric transcript by this translocation. The TLS/FUS gene has been identified as a translocated gene in myxoid liposarcoma by the t(12;16)(q13;p11) translocation and encodes an RNA-binding protein that is highly homologous to the product of the EWS gene involved in Ewing's sarcoma. Thus, the TLS/FUS-ERG gene fusion in t(16;21) leukemia is predicted to produce a protein that is very similar to the EWS-ERG chimeric protein responsible for Ewing's sarcoma.

Base Sequence↗
PubMed1994

Generation of the AML1-EVI-1 fusion gene in the t(3;21)(q26;q22) causes blastic crisis in chronic myelocytic leukemia.

The t(3;21)(q26;q22) translocation, which is one of the consistent chromosomal abnormalities found in blastic crisis of chronic myelocytic leukemia (CML), is thought to play an important role in the leukemic progression of CML to an acute blastic crisis phase. The AML1 gene, which is located at the translocation breakpoint of the t(8;21)(q22;q22) translocation found in acute myelocytic leukemia, was also rearranged by the t(3;21)(q26;q22) translocation. Screening of a cDNA library of the t(3;21)-carrying leukemic cell line cells (SKH1) resulted in the isolation of two potentially complete AML1-EVI-1 chimeric cDNAs of 6 kb. Two species of AML1-EVI-1 fusion transcripts of 8.2 and 7.0 kb were detected in SKH1 cells. These cells expressed the 180 kDa AML1-EVI-1 fusion protein containing an N-terminal half of AML1 including a runt homology domain which is fused to the entire zinc finger EVI-1 protein. The AML1-EVI-1 fusion transcript was consistent in all three cases of the t(3;21)-carrying leukemia examined by RNA-based PCR. These findings strongly suggest that the t(3;21) translocation results in the formation of a new class of chimeric transcription factor which could contribute to the leukemic progression of CML through interference with cell growth and differentiation.

3T3 Cells↗
PubMed1994

Sixty new STSs (sequence-tagged sites) of human chromosome 21.

From human chromosome 21-specific libraries, 22 SfiI linking clones and 38 P1 clones were isolated and regionally mapped on the chromosome. The terminal sequences of these clones were determined and pairs of PCR primers were generated which could specifically amplify the sequenced regions. These sequence-tagged sites (STSs) should be useful for constructing a high resolution map of human chromosome 21.

Base Sequence↗
PubMed1994

Association between anthropometric measures and spinal bone mineral density.

RATIONALE AND OBJECTIVES: The relationship of vertebral bone mineral density (BMD) to various anthropometric factors, including body weight and height, vertebral volume, and muscle area was examined. The sex- and menopause-related differences in these relationships also were studied. METHODS: Both cortical and trabecular BMD were measured using quantitative computed tomography (QCT). Integral BMD was measured using dual x-ray absorptiometry (DXA) in 74 men and in 96 premenopausal and 155 postmenopausal women. The psoas muscle area was measured using CT images. Vertebral volume was determined using CT images and CT topography. RESULTS: Bone mineral density had the strongest relationship with age in postmenopausal women. Trabecular BMD was correlated with muscle area and vertebral volume in premenopausal women, but not in postmenopausal women. The correlation of trabecular BMD with various anthropometric factors in men was stronger than that in women. Dual x-ray absorptiometry-BMD was found to be more affected by bone volume than was QCT-BMD. CONCLUSIONS: The association of anthropometric factors with BMD differs in men and women, as well as in premenopausal and postmenopausal women.

Absorptiometry, Photon↗