Biomedical subjects

Shinichi Tsuchiya

Publications and source records attributed to Shinichi Tsuchiya.

3 recordsLinked to original sources

PubMed2005

The "spanning protocol": a new DNA extraction method for efficient single-cell genetic diagnosis.

PURPOSE: We evaluated methods of preparation of DNA from single cells for amplification and preimplantation genetic diagnosis (PGD), including our "spanning protocol." METHODS: Dystrophin gene exons 45 and 51 were amplified by nested polymerase chain reaction (PCR) from a single lymphocyte or blastomere. Amplification efficiencies were compared between DNA extraction by (A) lysis in distilled water with freeze-thawing and boiling; (B) two-step lysis involving potassium hydroxide and dithiothreitol; and (C) the spanning protocol, using N-lauroylsarcosine. RESULTS: With method A, amplification efficiency was 66/120 (55%) and false-positive such as amplification failure or allele drop out was 42/120 (35%); with B, 96/120 (80%) and 21/120 (17.5%); and with C, 111/120 (92%) and 5/120 (4.2%), using single blastomeres and unaffected lymphocytes from male. Occurrence of false-negative such as contamination of another DNA with method A was 4/120 (3.3%); with B, 10/120 (8.3%); and with C, 2/120 (1.7%) from using single lymphocytes from affected males. CONCLUSION: The spanning protocol was most efficient for extracting DNA from a single cell and should be particularly useful for preimplantation genetic diagnosis.

Blastomeres↗

PubMed2004

[Clinicopathological characteristics of atypical cystic duct (ACD) of the breast: assessment of ACD as a precancerous lesion].

OBJECTIVE: To assess the clinicopathological features of atypical cystic duct (ACD) as a precancerous lesion of the breast. METHODS: Whole mammary gland serial sections were performed on 200 cases of breast cancer without pre-operative biopsy (prior operation, fine needle aspiration or needle biopsy were routinely performed in each case). The clinicopathological findings and immunohistochemical features of ACD were investigated. RESULTS: Forty-four (22%) of the 200 breast cancer patients had ACD breast lesions. The frequency of patients with ACD increased in premenopausal women (P=0.001). A number of ACD lesions displayed a histological transition to adjacent ductal carcinoma in-situ. In 16 of 44 (36%) patients with ACD, carcinoma cells stained positive for p53. In 12 of these 16 cases (75%), ACD cells also stained positive for p53 protein (P=0.001). Myoepithelial cells of ACD appeared attenuated and stained strongly for alpha-smooth muscle actin. There was no correlation between the ACD-present group and the ACD-absent group in tumor size, nodal metastasis, and immunostaining patterns of estrogen receptor (ER), progesterone receptor (PR), p53, c-erbB-2 and Ki-67 labeling index of cancerous tissues. All 44 ACD lesions showed a negative staining of c-erbB-2, regardless of the staining result in their corresponding carcinomas. The mean Ki-67 labeling index of ACD lesions was low. CONCLUSIONS: ACD is frequently associated with breast cancer. It may represent a precancerous mammary lesion, supported by the frequent histological continuum between ACD and malignancy, and simultaneous p53 over-expression present in both ACD and its corresponding breast carcinoma.

Biomarkers, Tumor↗

PubMed2002

Correlation of allelic losses and clinicopathological factors in 504 primary breast cancers.

BACKGROUND: We have defined 18 chromosomal regions in which allelic losses were frequent among breast cancers. We examined whether specific allelic losses might correlate with any clinicopathological factors. METHODS: We tested DNA from matched normal and tumor tissues for loss of heterozygosity (LOH) at 18 microsatellite loci from a cohort of 504 patients who had undergone surgery for breast cancer. RESULTS: LOH at 3p14.3 correlated with a larger size of tumor (greater than 2 cm). LOH at 1p22, 3p25.1, 3p14.3, or 17q21.1 correlated with loss of estrogen receptors. LOH at as many as eleven regions correlated with loss of progesterone receptor, suggesting that these represent general phenomena associated with progression of cancer. Above all, allelic losses at 11q23-24, 13q12, 17p13.3, or 22q13 significantly correlated with lymph-node metastasis (11q23-24, p= 0.0042; 13q12, p=0.0207; 17p13.3, p=0.0478; 22q13, p=0.0162). CONCLUSION: These results suggest that some clinical characteristics of breast cancers are determined by loss of tumor suppressor genes present at specific chromosome regions. Especially, LOH at 11q23-24, 13q12, 17p13.3, and 22q13 is a significant predictor of lymph-node metastasis for patients who have undergone surgery for breast cancer, and may serve as a negative prognostic indicator.

Adult↗