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Kiyomi Yamazaki

Publications and source records attributed to Kiyomi Yamazaki.

6 recordsLinked to original sources
PubMed2006

Hunchback sequence binding protein suppresses mouse TGF-beta3 promoter in vitro.

Transforming growth factor-beta3 (TGF-beta3) has a specific role in vivo in the patterning of embryonic and tissue-specific gene expression. We have cloned and sequenced the mouse TGF-beta3 5'-flanking region to study the transcriptional regulation of this gene. Promoter fragments were cloned into a promoterless luciferase reporter plasmid to study functional activity in a human skin melanoma cell line A375 (A375). Sequential 5'-deletion encompassing DNA sequences from -2297 to -1003 bp exhibited high promoter activity in A375 cells, whereas the promoter activity decreased to minimal in the -742 to 104 bp regions, suggesting both positive and negative transcriptional regulation in the TGF-beta3 promoter. The fragment containing 1.8 kb had the highest luciferase activity. Characterization of this 1.8 kb 5'-flanking region upstream of the translation start site showed a putative hunchback-binding site consensus sequence. The electrophoretic mobility shift assay (EMSA) and transient transfection experiments showed that the putative hunchback-binding site is functional and regulated TGF-beta3 promoter transcriptional activity. The DNA-complex including the hunchback sequence binding protein (HbSBP) was important for suppression of the promoter activity in A375 cells. Mutation of the hunchback consensus sequence resulted in up to 2-fold higher promoter activity than the wild type construct. There was an absence of HbSBP in other cell lines tested including 3T3 fibroblast and B-16 mouse skin melanoma as determined by EMSA and Western blot analysis. HbSBP may function as a TGF-beta3 gene transcriptional regulator and may be expressed in a cell type-specific manner.

Animals↗
PubMed2006

An instructive case suggesting cyclical primary hyperparathyroidism.

We report an instructive case of primary hyperparathyroidism in which cyclical secretion of PTH may have caused repeated hypercalcemic crises followed by temporary remission with a spontaneous drop in PTH. A 64-year-old man was admitted to our hospital twice with severe hypercalcemic crisis (corrected calcium (cCa) 15.0 mg/dl and 16.7 mg/dl) accompanied by an increase in intact PTH (220 pg/ml and 470 pg/ml). During both events, the serum PTH values spontaneously dropped followed by remission of the hypercalcemia. The tumor, detected at the left-upper side, showed neither vascularity on ultrasound examination nor washout delay on MIBI scintigraphy, suggesting that two parathyroid adenoma infarctions had occurred. Cervical exploration was undertaken. The histopathological examinations confirmed that the tumor was parathyroid adenoma. Contrary to our expectation, however, it did not reveal necrotic tissue that would indicate recent infarction. The findings in this case may be explained by cyclical secretion of PTH from a parathyroid adenoma. Although cyclical Cushing's syndrome is well known, to our knowledge this is the first documented case suggesting cyclical primary hyperparathyroidism.

Bone Density↗
PubMed2005

Probability of axillary lymph node metastasis when sentinel lymph node biopsy is negative in women with clinically node negative breast cancer: a Bayesian approach.

BACKGROUND: Although sentinel lymph node biopsy(SLNB)is highly accurate in predicting axillary nodal status in patients with breast cancer, it has been shown that the procedure is associated with a few false negative results. The risk of leaving metastatic nodes behind in the axillary basin when SLNB is negative should be estimated for an individual patient if SLNB is performed to avoid conventional axillary lymph node dissection(ALND). METHODS: A retrospective analysis of 512 women with T1-3N0M0 breast cancer was conducted to derive a prevalence of nodal metastasis by T category as a pre-test(i.e., before SLNB)probability and to examine potential confounders on the relationship between T category and axillary nodal involvement. Probability of nodal metastasis when SLNB was negative was estimated by means of Bayes' theorem which incorporated the pre-test probability and sensitivity and specificity of SLNB. RESULTS: Axillary nodal metastasis was observed in 6.1% of T1a-b, 25.1% of T1c, 28.7% of T2, 35.0% of T3 tumors. Point estimates for the probability of nodal involvement when SLNB was negative ranged from 0.3-1.3% for T1a-b, 1.6-6.3% for T1c, 2.0-7.5% for T2, and 2.6-9.7% for T3 tumors with representative sensitivities of 80%, 85%, 90% and 95%, respectively. The risk may be higher when the tumor involves the upper outer quadrant of the breast, while it may be lower for an underweight woman. CONCLUSIONS: The probability of axillary lymph node metastasis when SLNB is negative can be estimated using a Bayesian approach. Presenting the probability to the patient may guide the decision of surgery without conventional ALND.

Adult↗
PubMed2004

Prehistoric Sado Island populations of Sus scrofa distinguished from contemporary Japanese wild boar by ancient mitochondrial DNA.

Ancient mitochondrial DNA (mtDNA) mainly from Jomon Period Sus scrofa bone specimens (6,100-1,700 years old) was examined to clarify the genetic relationships between prehistoric and contemporary S. scrofa on Hokkaido, Honshu, Sado, and Izu islands of the Japanese Archipelago. Phylogenetic analysis of the mtDNA control region (574 bp) and analysis of pairwise nucleotide differences between prehistoric and contemporary S. scrofa sequences showed the following relationships between these groups: (1) a group genetically similar to contemporary Japanese wild boars was found mainly on Honshu Island, Hokkaido Island, and the Izu Islands, and (2) a monophyletic group distinct from contemporary Japanese wild boars was found on Sado Island. These results suggest that prehistoric people introduced S. scrofa from Honshu Island to Hokkaido Island and the Izu Islands. The estimated divergence times between the prehistoric Sado group and the other prehistoric S. scrofa is approximately congruent with the geological isolation of Sado Island from Honshu Island. Our results suggest that this extinct S. scrofa population was present on Sado Island as recently as around 2,000 years ago.

Animals↗
PubMed2003

Adrenal-preserving laparoscopic surgery in selected patients with bilateral adrenal tumors.

BACKGROUND: There have been few reports of laparoscopic adrenal-sparing surgery for bilateral adrenal tumors. We review our experience with this type of surgery with the aim of evaluating its feasibility and safety. METHODS: Over a 4-year period, we treated 9 patients with bilateral benign adrenal tumors. Seven patients had bilateral pheochromocytomas (MEN 2: 5, VHL: 1, sporadic: 1), and 2 patients had Cushing's syndrome caused by bilateral adrenocortical adenomas. Laparoscopic procedures were performed by a flank approach. The mean diameter of the tumors was 3.7 cm (range, 2.0-8.5 cm). RESULTS: All the tumors were removed laparoscopically. Four patients with hereditary pheochromocytomas underwent bilateral total adrenalectomy because of the large tumor size and multiplicity. The other 5 patients were treated successfully with preservation of adrenocortical function. In 4 of these 5 patients, the adrenal tumors were 3 cm or less in diameter. None of the patients experienced surgical complications. At a mean follow-up of 16 months (range, 4-40 months), none of the 5 patients who were treated by adrenal-sparing surgery required corticosteroid replacement. CONCLUSION: Laparoscopic surgery is feasible for the treatment of bilateral adrenal tumors. Adrenal-preserving laparoscopic surgery may be practicable for the removal of these tumors, if the tumor on either side is 3 cm or less in diameter; however, our follow up is short (mean, 16 months).

Adrenal Gland Neoplasms↗