Biomedical subjects

Makoto Kammori

Publications and source records attributed to Makoto Kammori.

6 recordsLinked to original sources

PubMed2003

Demonstration of human telomerase reverse transcriptase (hTERT) in human parathyroid tumours by in situ hybridization with a new oligonucleotide probe.

BACKGROUND AND OBJECTIVE: Telomerase activity is present in most malignant tumours and might provide a mechanism for unlimited replication of neoplastic cells. Expression of the gene encoding human telomerase reverse transcriptase (hTERT), the telomerase catalytic subunit gene, is associated with telomerase activity, and it is overexpressed in most parathyroid carcinomas. We have therefore studied hTERT expression in parathyroid tumours. METHODS: In the present study, we assayed telomerase activity by the telomeric repeat amplification protocol (TRAP) and used in situ hybridization (ISH) to study hTERT mRNA expression in four parathyroid metastatic cancers, six adenomas and two parathyroid hyperplasia tissue specimens. RESULTS: Telomerase activity was detected by the TRAP assay in all of the parathyroid cancers (100%) but in none of the eight parathyroid benign lesions. hTERT gene expression was detected in the nuclei of the parathyroid cancer cells in all of the lesions (100%) but in none of the eight parathyroid benign lesions. CONCLUSIONS: Our results demonstrate a correlation between telomerase activity and hTERT gene expression measured by ISH (P < 0.001) in parathyroid tumours. We succeeded in very clearly and sensitively demonstrating hTERT mRNA in parathyroid tissues by using a new probe.

Adenoma↗

PubMed2003

Clinical application of human telomerase reverse transcriptase gene expression in thyroid follicular tumors by fine-needle aspirations using in situ hybridization.

Most of fine-needle aspiration (FNA) biopsies for follicular tumors of the thyroid are deemed 'indeterminate' or 'suspicious' with regard to malignancy, even though most of these lesions are benign. Therefore, additional diagnostic markers of malignancy are needed. Telomerase activity is present in most malignant tumors. Expression of the gene encoding human telomerase reverse transcriptase (hTERT) is very closely associated with telomerase activity, this gene is overexpressed in most thyroid carcinomas. We examined telomerase activity by the telomeric repeat amplification protocol (TRAP) and hTERT gene expression by in situ hybridization (ISH) in thyroid tissue including 6 follicular carcinomas and 15 follicular adenomas. ISH for hTERT gene was performed using FNA samples from the same patients. Telomerase activity was detected in all six of the follicular carcinomas and in five (33%) of the 15 follicular adenoma tissue specimens. hTERT gene expression was detected the follicular cancer cells in all of the lesions and in one (7%) of the 15 thyroid adenomas. Moreover, we demonstrated that hTERT gene expression was occurring in four (67%) of the 6 follicular carcinoma biopsy specimens obtained using FNA. These results suggest that the detection of hTERT gene expression using ISH tissue specimens can be used to distinguish between benign and malignant follicular lesions of the thyroid, however the detection of hTERT gene in FNA samples using ISH cannot be used to definitively diagnose follicular tumors of the thyroid.

Adenocarcinoma, Follicular↗

PubMed2002

Consistent decrease in telomere length in parathyroid tumors but alteration in telomerase activity limited to malignancies: preliminary report.

Telomerase is known to be activated and telomere length altered in various types of malignant and benign tumors, but whether this is also the case for parathyroid lesions has hitherto been unclear. We therefore investigated telomerase activity and telomere length in 3 parathyroid metastatic cancers, 6 adenomas, 2 cases of parathyroid hyperplasia, and 16 samples of normal parathyroid tissue. Telomerase activity, assayed by the telomeric repeat amplification protocol, was detected in all of the parathyroid cancers (100%), in none of the 8 parathyroid benign lesions, and in only 1 of the 16 normal parathyroid samples (8.3%). Telomere length, determined by the terminal restriction fragment assay, was reduced in the tumor tissues with a mean telomere length of 8.23 +/- 0.86 kbp compared with the 12.61 +/- 0.81 kbp for the 16 age-matched subjects (p = 0.002). The results indicate that telomerase activity and telomere length may reflect the biologic behavior of individual parathyroid lesions.

Adenoma↗

PubMed2002

Telomere shortening with aging in human thyroid and parathyroid tissue.

Progressive telomere shortening with aging was studied using normal thyroid tissue specimens from 46 human subjects aged between 0 and 98 yr and normal parathyroid tissue specimens from 21 human subjects aged between 0 and 83 yrs. There has hitherto been no information documented about telomere length in such thyroid and parathyroid tissues. Age-related shortening at rates of 91 and 92 base pairs (bp) per year, respectively, were observed. Telomere lengths of normal thyroid tissues were 16.53 +/- 1.10 (mean +/- SE), 14.31 +/- 0.80, 11.27 +/- 0.68 and 8.73 +/- 1.08 kbp for age groups less than 2, 20-50, 51-80 and more than 80 yr. Telomere lengths of normal parathyroid tissues were 15.80 +/- 1.46 (mean +/- SE), 15.36 +/- 0.86 and 10.93 +/- 0.78 kbp for age groups less than 4, 20-50 and 51-80 yr. Telomere shortening occurred after 50 yr of age in thyroid and parathyroid tissues. Human thyroid and parathyroid tissues do not seem to show the rapid reduction in telomere length early in life that was reported for some human cell types, suggesting that the rate of telomere shortening has tissue-specific characteristics.

Adult↗

PubMed2002

Oncocytic adenocarcinoma of the stomach: parietal cell carcinoma.

We report 10 cases of an unusual type of gastric adenocarcinoma that occurred in elderly patients 58-81 years of age. Histologically, the tumors were well to moderately differentiated tubular adenocarcinomas with very eosinophilic, finely granular cytoplasm. Immunohistochemical stains for antimitochondrial antibody were strongly positive. Ultrastructurally, the tumor cells had numerous mitochondria in their cytoplasm and occasional intracytoplasmic lumina with associated long microvilli. These histologic and ultrastructural features are similar to those of parietal cells in normal gastric fundic mucosa, but immunohistochemical staining of the tumors using four different antiparietal cell antibodies (anti-H(+)-K(+)-adenosine triphosphatase antibodies) was negative in all cases. Therefore, we think that these tumors were not parietal cell carcinomas but could be termed oncocytic adenocarcinomas, or adenocarcinomas with oncocytic differentiation. Previously reported cases of parietal cell carcinoma have been said to have a favorable prognosis, but it will be necessary to study a larger number of cases to determine the prognosis of oncocytic adenocarcinoma.

Adenocarcinoma↗

PubMed2002

Demonstration of human telomerase reverse transcriptase in human colorectal carcinomas by in situ hybridization.

Telomerase activity is present in most malignant tumors and provides a mechanism for unlimited replication of neoplastic cells. Expression of the gene encoding human telomerase reverse transcriptase (hTERT), the telomerase catalytic subunit gene, is associated with telomerase activity, and it is overexpressed in most colorectal carcinomas. In the present study we assayed telomerase activity by the telomeric repeat amplification protocol (TRAP) and used in situ hybridization (ISH) and the reverse transcription polymerase chain reaction (RT-PCR) to study hTERT expression in colorectal carcinomas and adjacent normal tissues. Telomerase activity was found in 30/35 (85.7%) of normal mucosae and 35/35 (100%) of adenocarcinomas, and RT-PCR detected hTERT in 33/35 (94.3%) of the carcinomas. ISH, on the other hand, detected weak but significant expression of hTERT in a significant percentage of lymphocytes infiltrating normal colorectal mucosa. hTERT gene expression was detected in the nuclei of adenocarcinoma cells in 27/35 (77.1%) of the lesions. The results of our comparison of telomerase activity and hTERT gene expression by RT-PCR-based ISH appeared contradictory, but a careful review suggested that the discrepancy was attributable to contamination by infiltrating lymphocytes. Our findings suggest that ISH-based analysis of hTERT gene expression is superior to both TRAP telomerase activity and hTERT mRNA RT-PCR analysis as a means of determining telomerase status during carcinogenesis.

Aged↗