Biomedical subjects

Q Yang

Publications and source records attributed to Q Yang.

529 records · Page 30Linked to original sources

PubMedDate not supplied

Biological characterization of central and peripheral primary non small cell lung cancers (NSCLC).

BACKGROUND: Non Small Cell Lung Carcinomas (NSCLC) comprise 90% of all lung carcinomas. Studies have demonstrated a preferential central (bronchus-derived) localization for squamous cells, whereas adenocarcinomas are frequently peripheral (bronchiolo-alveolus derived). It has been suggested that exposure to carcinogenic insults including cigarette smoke, may induce different types of tumors in different locations. MATERIALS AND METHODS: Forty one NSCLC patients staged according to WHO and TNM were considered for localization and biological parameters (p53 expression, cell ploidy and S-phase). RESULTS: p53 overexpression was found more frequently in central than in peripheral tumors (69% vs 39%) (p = 0.074). Central tumors were more aneuploid (69%) than peripheral ones (46%) (p = 0.03) No difference in smoking habit was observed in the two groups. CONCLUSIONS: Our results suggest that there is no apparent biological difference between these two groups of NSCLCs, and that the smoking does not play a role in either histotype determination or biological behavior.

Adenocarcinoma↗

PubMedDate not supplied

Thymidine phosphorylase expression in invasive carcinoma: correlations with clinicopathologic variables and in vitro chemosensitivity to 5-fluorouracil.

BACKGROUND: Thymidine phosphorylase (TP) is critical for angiogenic activity, but little information is available on the relationship between TP expression and other Clinicopathologic variables. Furthermore, the relationship between TP and chemosensitivity is still debated. MATERIALS AND METHODS: The expression of TP was examined in 116 primary breast carcinomas and in vitro chemosensitivity was assessed in 67 of them by histoculture drug response assay (HDRA) using 5-fluorouracil (5-FU). RESULTS: Tumor cell TP expression was significantly inversely correlated with histological grade and positively correlated with Bcl-2 expression, but no association with other tumor variables was found. Unexpectedly, TP immunoreactivity was not related to 5-FU chemosensitivity. CONCLUSION: The present results suggest that TP is important for remodeling the existing vasculature early in tumor development and intraductal extension, expressions of TP and Bcl-2 are tightly linked and TP status can not generally predict chemotherapeutic sensitivity for 5-FU as a single molecular marker.

Antimetabolites, Antineoplastic↗

PubMedDate not supplied

Overexpression of p27 protein in human breast cancer correlates with in vitro resistance to doxorubicin and mitomycin C.

BACKGROUND: The cycle regulatory protein p27, an inhibitor of cyclin-dependent kinase (CDK), has been attributed a role in resistance to cancer chemotherapy. However, the predictive value of p27 for chemosensitivity of breast cancer is still unclear. We therefore analyzed the in vitro chemosensitivity to a series of anticancer agents in fresh breast cancer specimens and correlated it with the respective expression levels of p27. MATERIALS AND METHODS: The expression of p27 protein was examined immunohistochemically in 119 patients with primary breast cancer. The in vitro chemosensitivity was assessed by the histoculture drug response assay (HDRA) using mitomycin C (MMC), 5-fluorouracil (5-Fu), Doxorubicin (DXR), cisplatin (CDDP) and cyclophosphamide (CPA). RESULTS: Fifty-six (47%) of the 119 patients demonstrated p27 overexpression. The susceptibility of DXR and MMC in tumors with high p27 expression was significantly higher than that in tumors with low p27 expression. CONCLUSION: Immunohistochemical results regarding p27 might be therapeutically useful as an indicator of response to DXR and/or MMC based adjuvant chemotherapy for breast cancer.

Antineoplastic Agents↗

PubMedDate not supplied

Novel polymorphisms in prostate specific antigen gene and its association with prostate cancer.

Prostate-specific antigen (PSA) is now used widely for the diagnosis and monitoring of patients with prostate cancer. The PSA gene is a target of the androgen receptor (AR) which interacts with androgen response elements (AREs) in the PSA gene promoter. Recently, we identified two novel polymorphisms in the PSA promoter ARE2 region in breast cancer. We hypothesized that some genetic variations might also exist in the AREs of prostate cancer, and that feature might correlate with cancer development and/or progression. To test this hypothesis, three AREs of the PSA gene promoter were characterized for 47 prostate cancer cases and 105 controls from the Japanese population. We demonstrated the presence of two polymorphisms at positions -252 (G or A) and -205 (A or AA), which were the same as those we have found in breast cancer. Interestingly, the -252 A was linked with the presence of -205 AA, and the -252 G was always linked with the presence of -205 A. Therefore, only A-AA and G-A (-252--205) alleles were present in the Japanese population. The proportion of patients who were either heterozygotes or homozygotes for the A-AA allele was not significantly different from that observed among 105 individuals without cancer (p = 0.726). However, comparing with G-A allele homozygotes, prostate cancer patients carrying at least 1 A-AA alleles tended to exhibit high serum PSA levels (p = 0.0002), poor differentiation (p = 0.0149) and advanced clinical stage (p = 0.0077). These results suggest that the novel polymorphisms identified in the PSA gene promoter may affect transcriptional activity of the PSA gene, and an excess of PSA production may enhance rapid progression of prostate cancer.

Aged↗

PubMedDate not supplied

Hypermethylation does not account for the frequent loss of the retinoic acid receptor beta2 in breast carcinoma.

Hypermethylation of the retinoic acid receptor (RAR) beta2 has been detected in breast cancer cell lines and is known to repress the level of RAR beta2 transcription. RAR beta2 mRNA loss has often been detected in breast cancer tumors, whether promoter region methylation of the RAR beta2 gene accounts for its loss is still unknown. We examined the methylation status of RAR beta2 in breast tumors; 21 out of 50 (42%) breast tumors showed RAR beta2 hypermethylation. RT-PCR analysis showed a complete loss of RAR beta2 mRNA expression in 15 out of 43 (35%) breast tumors. No correlation between the hypermethylation and RAR beta2 loss was found, suggesting that hypermethylation is not fully responsible for the loss of expression of the RAR beta2 gene during breast tumorigenesis.

Aged↗

PubMedDate not supplied

Metabolic rate and nitrogen balance after skeletal trauma in female and male rats.

Unequal metabolic responses to trauma by women and men have been suggested, but an explicit investigation demonstrating this conjecture has not been made. The responses of resting energy expenditure (REE) and nitrogen balance for 3 days before and 7 days after skeletal trauma were determined for female and male rats. Food intake and body weight were recorded daily, and 24-h urine samples were collected. Baseline REE and nitrogen balance were obtained for 3 consecutive days before induction of trauma. Then rats were divided into female trauma (n = 8), male trauma (n = 7), female control (n = 8), and male control (n = 7) groups. Trauma was produced by bilateral femoral fracture to anesthetized rats. Control rats were anesthetized without skeletal trauma. Traumatized rats were fed ad libitum for 7 days, and control rats were pair fed with the traumatized rats. The results showed that REE increased and nitrogen balance decreased in traumatized male rats relative to their controls. Traumatized female rats had increased REE and unchanged nitrogen balance compared with their controls. Traumatized female rats had a larger percentage increase in REE on days 5 through 7 than did traumatized male rats. These findings demonstrate a difference between female and male rats in response to trauma. Female rats use more energy and lose less nitrogen after trauma than do male rats. The results suggest that recommendations for increased energy and protein needs after trauma should consider the sex of the subject intended to be fed.

Animals↗

PubMedDate not supplied

A needle-type sensor for monitoring glucose in whole blood.

A new surface-process technology employing electrochemical fixation of a bioactive substance (enzyme and heparin) to a sensor electrode was developed to provide biocompatability and functionality. The fabrication process includes electroentrapment of glucose oxidase and heparin on a platinum electrode by using 1,3-phenylenediamine codeposition. Electrochemically grown 1,3-phenylenediamine was also used as the outer coating of the sensor's enzyme electrode in order to extend the linear range. The sensor shows a sensitivity of 3 nA/mM and a linear range from 40 to 400 mg/dL at 37 degrees C when tested in whole blood. This sensor is characterized by a fast response. The sensor shows a minimum change in its performance when stored inactive in buffer for 12 weeks. When tested at physiologic glucose levels, the sensor demonstrates satisfactory low interference from common interfering substances. This technology seems promising for the preparation of implantable intravascular biosensors.

Anticoagulants↗