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N Yahata

Publications and source records attributed to N Yahata.

At least 37 records · Page 2Linked to original sources
PubMed1998

Telomerase activity in lung cancer cells obtained from bronchial washings.

BACKGROUND: Telomerase, a ribonucleoprotein enzyme that functions in the maintenance of telomeres (specialized structures at the ends of chromosomes), has been reported to be a novel diagnostic marker for malignant diseases. We sought to determine whether measurement of telomerase activity in bronchial washings is of value in the diagnosis of lung cancer. METHODS: Extracts of cells in bronchial washings were analyzed for telomerase activity by use of a telomeric repeat amplification protocol (TRAP) assay. Telomerase activity inside cells was evaluated by use of an in situ TRAP assay. The results of both TRAP assays were compared with those obtained from cytologic examination, which employed standard Papanicolaou staining. RESULTS: When results from the two TRAP assays were combined, telomerase activity was detected in bronchial washings from 18 (82%; 95% confidence interval [CI] = 60%-95%) of 22 patients with lung cancer. In contrast, cancer cells were detected by cytologic examination in the bronchial washings of nine (41%; 95% CI = 21%-64%) of the same 22 patients, a statistically significant difference (two-sided P = .0061). In patients with lung cancer, telomerase-positive cells could be detected in bronchial washings irrespective of tumor location--11 of 14 (79%; 95% CI = 49%-95%) peripheral cancerous lesions and seven of eight (88%; 95% CI = 47%-100%) central cancerous lesions were detected by use of TRAP assays (for comparison, two-sided P = .5349). CONCLUSIONS: A high percentage of patients with lung cancers had detectable telomerase activity in bronchial washings. Thus, the use of a cell extract-based or an in situ TRAP assay in addition to cytologic examination may make the diagnosis of lung cancer more reliable.

Adult↗
PubMed1998

Telomeric length and telomerase activity vary with age in peripheral blood cells obtained from normal individuals.

The telomerase activity and length of telomeres of peripheral blood mononuclear cells obtained from 124 healthy individuals aged 4-95 years was measured. Telomerase activity level was semiquantitatively assessed by a fluorescent-telomeric repeat amplification protocol (fluorescent-TRAP) using an internal telomerase assay standard, fluorescent primers and an automated laser fluorescent DNA sequencer. Telomeric length, measured by assay of terminal restriction fragments (TRFs), was determined in HinfI-digested DNA by Southern blot analysis using a (TTAGGG)4 probe. TRF length was determined in 80 individuals and age-related progressive reduction of size was observed. TRF length in peripheral blood mononuclear cells obtained from normal individuals (aged 4-39 years) decreased by approximately 84 bp per year, while in individuals aged > or = 40 years it decreased by 41 bp per year. In contrast, telomerase activity showed an apparent biphasic pattern with aging. Individuals aged 4-39 years showed a progressive decrease in telomerase activity, whereas 65% of those aged > or = 40 years showed relatively stable but very low telomerase activity, and the remaining individuals aged > or = 40 years had no detectable telomerase activity. These data obtained from normal individuals might in the future be of value to help risk stratify and manage the care of patients with leukemia.

Adolescent↗
PubMed1998

A sole del(15q) anomaly in post-myelodysplasia acute myeloid leukemia.

We report the second case of post-myelodysplasia acute myeloid leukemia (post-MDS AML) with a sole chromosome change del(15q). This anomaly is rarely seen. To our knowledge, only seven cases so far have been reported in human neoplasias, including one case each of acute myeloid leukemia (AML), acute lymphoid leukemia, post myelodysplasia AML, myelodysplastic syndrome, myelofibrosis, macroglobulinemia, Hodgkin's lymphoma and uterine leiomyoma. This case suggests that del(15q) is related to lympho-myeloproliferative disorders. Moreover, we speculate that certain oncogene(s) located on 15q might have some role in the progression of the disease, since the del(15q) anomaly appeared only in the AML phase in this case.

Acute Disease↗
PubMed1998

Human cord blood-derived primitive progenitors are enriched in CD34+c-kit- cells: correlation between long-term culture-initiating cells and telomerase expression.

We studied the functional characteristics of subpopulations of cord blood-derived CD34+ cells expressing different levels of CD38 and c-kit antigens, using clonal cell culture and long-term culture with allogeneic bone marrow stromal cells or the MS-5 murine stromal cell line to assay long-term culture-initiating cells (LTC-IC) in each subpopulation. To investigate the capacity for replication, proliferation, and differentiation of each subpopulation of CD34+ cells, we also studied the correlation between LTC-IC and telomerase activity. After 5 weeks of coculture, LTC-IC accounted for one out of 32 CD34+CD38- cells and one out of 33 CD34+c-kit- cells. In contrast, the frequency of LTC-IC was low in their antigen-positive counterparts (one per 84 CD34+CD38+ cells, one per 90 CD34+c-kit(low) cells, and very low among CD34+c-kit(high) cells). It was noteworthy that some LTC-IC derived from CD34+CD38- as well as CD34+c-kit- cells generated colony-forming cells (CFCs) after up to 9 weeks of coculture. Telomerase activity was consistently low in CD34+CD38- and CD34+c-kit- cells compared to CD38+ or c-kit(high or low) cells, suggesting that CD34+CD38- or c-kit- cells are likely to be more quiescent. These results suggest that the CD34+CD38- and CD34+c-kit- cell populations are primitive stem/progenitor cells, and that the telomerase activity of these cells correlates with their proliferative capacity as well as their stage of differentiation.

Animals↗
PubMed1998

Comparison of telomerase activity in normal chorionic villi to trophoblastic diseases.

Trophoblasts are derived from the normal placenta, and they infiltrate into the endometrium and the maternal blood vessels under strict control but, unlike malignant cells, never metastasize. To understand the proliferative characteristics of trophoblasts and its related disorders, we assessed telomerase activity in chorionic villi obtained from 27 normal individuals, 9 hydatidiform moles, and 2 choriocarcinomas. Telomerase activity was detected in 13/27 (48%) normal chorionic villi samples. The detectability and the level of telomerase activity depended on gestational age; 8/10 (80%) villi samples in the first trimester (relative telomerase activity; 1.77 +/- 1.37), whereas 2/8 (25%) villi samples in the second trimester (0.78 +/- 1.52) and 3/9 (33%) in the third trimester (0.28 +/- 0.43) had telomerase activity. Telomerase activity of normal chorionic villi in the first trimester was higher than that of the third trimester (P = 0.0251). In contrast, all mole samples had increased telomerase activity compared to normal villi (3.17 +/- 2.81, P = 0.0152). Thus, a relationship may exist among cell proliferation, telomerase activity, and progression to trophoblastic disease.

Adult↗
PubMed1998

Serum soluble CD44 levels for monitoring disease states in acute leukemia and myelodysplastic syndromes.

To determine the clinical implications of soluble CD44 (sCD44) levels in hematologic neoplasias, we developed an enzyme-linked immunosorbent assay for sCD44 using two monoclonal antibodies to the standard 90 kDa form, and assessed the serum concentration of sCD44 in normal healthy volunteers, patients with acute leukemia, myelodysplastic syndromes (MDS), and those with chronic myeloid leukemia (CML). Compared to that in normal individuals (n=51; 145. 1 24.6 ng/ml), the serum sCD44 level was significantly elevated in patients with acute myeloid leukemia (AML; n=18; 331.9 99.0 ng/ml, P=0.0001), acute lymphoid leukemia (ALL; n=16; 551.3 427.8 ng/ml, P=0.0001) and CML (n=18; 262.0 97.5 ng/ml, P=0.0001). The sCD44 level was slightly elevated in patients with MDS (n=43; 173.8 54.9 ng/ml, P=0.0071). In patients with acute leukemia, serum sCD44 concentrations decreased significantly in response to treatment and reached nearly normal levels after complete remission (P=0.0005 in AML and P=0.0032 in ALL). The sCD44 levels in patients with MDS increased after they developed acute leukemia, whereas no significant difference in sCD44 levels was observed between the chronic and the blastic phases in patients with CML. Our results indicate that serum sCD44 levels may be a useful marker for monitoring response to treatment and disease progression, especially in acute leukemia.

Acute Disease↗
PubMed1998

[Development of in situ TRAP assay detecting telomerase activity in cell].

Telomerase is a ribonucleoprotein that is detected in more than 85% of primary cancer tissues using a telomeric repeat amplification protocol (TRAP) assay. Thus, telomerase is considered to be a novel marker for cancer. Telomerase activity is not detectable in somatic cells, except for hematopoietic cells and cryptic cells in the intestine and hair follicles, thus, detection of telomerase is important to delineate clinical implication of telomerase activity. We have developed semiquantitative fluorescence-based TRAP assay using fluorescence-end-labeling primers. Moreover, we also developed an in situ TRAP assay that detects telomerase activity at the cellular level. Using these TRAP assays, we are able to detect telomerase activity in various kinds of extracts or cytological specimens and therefore these applications may have additive information in the early detection of cancer and monitoring disease condition.

Biomarkers, Tumor↗
PubMed1998

[The advantage of an in situ TRAP assay for the detection of telomerase activity using bronchial washings obtained from lung cancer patients].

In most previous reports telomerase activity in lung cancer patients has been detected using tissue extracts. We have developed a semiquantitative fluorescence-based TRAP assay using fluorescence-end-labeling primers. Moreover, we also developed an in situ TRAP assay that detects telomerase activity at the cellular level. Thus, using these TRAP assays, we can detect telomerase activity in lung cancer cells obtained from bronchial washings. A high incidence of lung cancer patients with class I-III cytology had detectable telomerase activity, thus, a combination of a cell extract based. TRAP assay and an in situ TRAP assay may provide additive information to cytology for the diagnosis of lung cancer.

Bronchoalveolar Lavage↗
PubMed1998

[Telomerase activity and determination of cancer in urological neoplasias using exfoliated urinary cells: in situ TRAP assay and its application].

We determined telomerase activity semiquantitatively and in-cell telomerase activity in exfoliated urinary cells obtained from urological neoplasias. Semiquantitative determination of telomerase activity was performed using a fluorescent-based telomeric repeat amplification protocol (TRAP) and telomerase activity at the cellular level was determined by an in situ TRAP assay. Fluorescent-based TRAP assay detected urinary telomerase activity in about 80% patients with urological neoplasia before treatment, whereas urinary cells obtained from 30% patients after/during treatment with either chemotherapy or operation (class II-V) had detectable telomerase activity. In contrast, the in situ TRAP assay detected telomerase-positive cells in 85% patients before treatment and 60% patients after/during treatment. Of note is a dissociation of the results between fluorescent-based TRAP assay and that of in situ TRAP assay in some patients. Some patients without detectable telomerase activity using the fluorescent-based TRAP assay showed a low frequency of telomerase-positive cells in the urine. A combination of semiquantitative analysis and an in situ TRAP assay to detect telomerase-positive cells might be a useful tool in the detection and monitoring of patients with urological neoplasias.

Humans↗
PubMed1998

[*5q--syndrome].

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Anemia, Refractory↗
PubMed1997

[Detection of telomerase activity and its clinical application].

Telomerase is a ribonuclear protein that is detected in more than 90% of primary cancer tissues using a telomeric repeat amplification protocol (TRAP) assay, thus, telomerase is considered to be a novel marker for cancer. Telomerase activity is not detectable in somatic cells, except for hematopoietic cells and cryptic cells in the intestine and hair follicles, thus, quantitation of telomerase is important to delineate clinical implication of telomerase activity. We have developed semiquantitative fluorescence-based TRAP assay. Moreover, we also developed an in situ TRAP assay that detects telomerase activity at the cellular level. Thus, using these TRAP assays, we are able to detect telomerase activity in various kinds of extracts or cytological specimens and therefore these applications may have additive information in the early detection of cancer and monitoring disease condition.

Adult↗
PubMed1996

Antisense phosphorothioate oligonucleotide inhibits interleukin 1 beta production in the human macrophage-like cell line, U937.

To find more efficacious therapeutic possibilities for treatment of inflammatory disease, we studied the effects of antisense oligonucleotides on interleukin 1 beta (IL-1 beta) production of the human macrophage-like U937 cells. U937 cells were incubated with several kinds of oligonucleotides. Total human IL-1 beta production was determined using an enzyme-linked immunosorbent assay. An antisense phosphorothioate oligonucleotide (S-oligo), complementary to the sequence, including initiation codon of the IL-1 beta gene, inhibited IL-1 beta production in a dose-dependent and sequence-specific manner. The effect of the antisense S-oligo was neutralized by mixing with a sense but not with a scramble S-oligo. Cellular uptake of S-oligo scanned with a laser confocal imaging system was time and temperature dependent, and its intracellular distribution was mainly to the cytosols in U937 cells. Human IL-1 beta antisense S-oligo inhibited IL-1 beta production of U937 cells, suggesting a potential to reduce some kinds of inflammatory processes.

Base Sequence↗
PubMed1990

Structure of the gene encoding beta-1,3-glucanase A1 of Bacillus circulans WL-12.

The nucleotide sequence of the glcA gene encoding the precursor of extracellular beta-1,3-glucanase (beta Gl) A1, a polysaccharidase produced by Bacillus circulans WL-12, was determined. The putative glcA gene was 2046 bp long, encoding a polypeptide of 682 amino acids (aa). The N-terminal aa sequence of beta Gl produced in Escherichia coli harboring the glcA plasmid was identical to that of beta Gl A1 prepared from the culture fluid of B. circulans WL-12. In both proteins, cleavage of the signal sequence of pre-beta Gl occurred between Ala-38 and Ala-39 of the predicted sequences.

Amino Acid Sequence↗
PubMed1990

[MR images of gliomas].

MR images of 55 gliomas (23 malignant gliomas, 16 Grade I-II astrocytomas, 7 oligodendrogliomas, 5 pontine gliomas, 2 central neurocytomas and 2 ependymomas) were reviewed. Histological diagnosis was obtained in all of these gliomas. Morphologic appearance and signal intensities of each glioma were evaluated on T1 and T2 weighted images. Nearly isointensity areas which correspond to enhanced areas on CT scans were observed in all malignant gliomas, and 19 of 23 malignant gliomas (83%) showed heterogeneous intensities on MR images. On the other hand, 12 of 16 benign astrocytomas (75%), 5 of 7 oligodendrogliomas (71%) and all of 5 pontine gliomas showed homogeneous intensities. All of central neurocytomas and ependymomas were shown as a solid tumor with cysts and heterogeneous intensities. In conclusion, although MR images without Gd-DTPA seemed not to be superior to contrast CT in differentiating malignant gliomas from benign one, it appears significant to know some tissue characteristics on MR images of gliomas in differentiating from the other brain tumors.

Adolescent↗