Biomedical subjects

Mai Nguyen

Publications and source records attributed to Mai Nguyen.

23 records · Page 2Linked to original sources

PubMed2002

Tumor-specific DNA in plasma of breast cancer patients.

The presence of DNA fragments circulating in cancer patients was described a number of years ago. The mere presence of DNA in the circulation is not indicative of cancer. However, there are reports that apoptosis and necrosis of the cancer cells can increase the levels of circulating DNA. The study of plasma DNA with the detection of genetic abnormalities associated with specific cancers has produced some promising results. Primary cancer often harbors ras or p53 mutations and the detection of these mutations in free circulating DNA could indicate the presence of cancer. Other approaches have included detection of specific losses of heterozygosity (LOH), microsatellite instability (MI) and promoter hyper-methylation. For breast cancer, studies published to date have focused on detecting LOH, MI and methylation of the p16INK4A promoter. Good concordance between alterations in the primary tumor and detection of the same alterations in the circulation has been observed. Also, it is encouraging to note that DNA alterations have been detected in patients with small or even in situ lesions, indicating that circulating tumor DNA is shed early in the disease process. If 'universal' breast-specific DNA alterations can be identified, this approach may hold significant promise for early detection of breast cancer.

Adult↗

PubMed2002

Retraction.

Explore the source record for details and available documents.

Retraction Notice↗

PubMed2000

Selective Modulation of Paracortical Dendritic Cells and T-Lymphocytes in Breast Cancer Sentinel Lymph Nodes.

Sentinel nodes (SNs), the nodes nearest a primary tumor on the direct lymphatic drainage path, are the site of earliest metastases, and in melanoma show striking immune modulation. We evaluated SNs from breast cancer patients for evidence of similar immune perturbation. The purpose of this study was to evaluate whether SNs from patients with breast cancer show the alterations in the histology and cytology of the paracortical areas seen in SNs from patients with melanoma. Formalin-fixed and paraffin-embedded sections from 32 SNs and 32 nonsentinel nodes (NSNs) from patients with breast cancer were evaluated. Sections were stained with hematoxylin and eosin and with antibodies to S-100 protein and HLA-DR, DQ, and DP to identify interdigitating dendritic cells (IDCs), and by an antibody to CD43RA to delineate T lymphocytes. By computerized image analysis we evaluated the distribution, frequency, immunophenotype, and activation status of IDCs and associated T lymphocytes in SNs and NSNs. Average areas occupied by S-100-positive dendritic cells (DCs) in SNs and NSNs were 0.13% and 19.98%, respectively, of total nodal area (p < 0.0001). The average density of S-100-positive IDCs in SNs was 11.00/mm2 and in NSNs was 257.88/mm2 (p < 0.0001). In SNs 43.55% of DCs (4.93/mm2) were nondendritic, 51.92% (5.69/mm2) had short dendrites, and 5.2% were mature with long dendrites (0.62/mm2). In SNs the ratio of immature to mature IDCs was 7.95:1. In NSNs, 8.09% of DCs (8.5/mm2) were nondendritic, 28.22% (67.46/mm2) had short dendrites, and 63.07% (145.96/mm2) were mature DCs with long dendrites. The ratio of immature to mature DCs in NSNs was 1:6.66. The average areas occupied by HLA class II-positive DCs in SNs and NSNs were 4.21% and 31.82%, respectively, of total nodal area. The frequency of coexpression of S-100 and HLA class II by immature IDCs without dendrites was 11.27% in SNs and 15.00% in NSNs. In both SNs and NSNs (p < 0.001) all mature S-100-positive IDCs with long dendrites expressed HLA class II. CD43RA-positive T lymphocytes occupied 20.06% of total nodal area in SNs and 63.57% in NSNs (p < 0.0001). The SNs from breast cancer patients are profoundly immune modulated with, by comparison to NSNs, markedly reduced paracortical areas, densities of paracortical DCs, frequency of S-100-positive IDCs coexpressing HLA class II, and a predominance of immature nondendritic and poorly dendritic DCs.

Journal Article↗

PubMedDate not supplied

A sensitive and specific method for the determination of total ribavirin in human red blood cells by liquid chromatography-tandem mass spectrometry.

A sensitive and specific method using high-performance liquid chromatography (LC)-tandem mass spectrometry (MS) for the analysis of total ribavirin in human red blood cells (RBC) is developed and validated. The method involves the addition of an internal standard and perchloric acid, the conversion of ribavirin phosphorylated metabolites to ribavirin, purification with a solid-phase exchange cartridge, and LC-MS-MS analysis. The MS-MS is selected to monitor m/z 245-113 for ribavirin and m/z 250-113 for [13C]ribavirin using positive electrospray ionization. The calibration curve is linear over a concentration of 100-10,000 ng/mL with a limit of quantitation of 100 ng/mL. Mean interassay accuracy for quality control (QC) at 100, 1000, and 10,000 ng/mL are 101.8%, 99.4%, and 98.8%, respectively. Mean interassay precision (%CV) for QC at 100, 1000, and 10,000 ng/mL are 5.0%, 5.0%, and 2.5%, respectively. Extractibility of total ribavirin from RBC is confirmed with RBC obtained from a [(14)C]ribavirin-dosed monkey. The method is used to determine the free and total ribavirin concentration in human RBC obtained from hepatitis C patients treated with ribavirin.

Antiviral Agents↗

PubMedDate not supplied

The expression of ER beta protein correlates with vascular endothelial growth factor and its prognostic significance in human breast cancer.

Although cloning of ER beta has prompted a reevaluation of the role of ERs in human breast cancer and there have been many studies focusing on the clinical value of ER beta detection, however, few reports evaluated the prognostic significance of ER beta based on follow-up data. The VEGF gene transcription may be mediated by different ER subtypes directly. The aim of this study was to evaluate the relationship of angiogenesis factor VEGF with different ER subtypes and the prognostic value of ER beta and VEGF in 116 human breast cancer patients. Of these patients, 40 (34.5%) were ER beta protein high expressed and 76 (65.5%) were ER beta protein low expressed. When correlated the ER beta protein levels with other clinical characteristics, statistical significance (p<0.05) was found between ER beta protein expression and menopausal status, and tumor grade. No significance was found between ER beta protein level and node status, stage, or tumor size. Inverse relationship was found between ER beta protein expression and PR status (p<0.05). When comparing the VEGF levels with different ER subtypes a significant difference between ERs and VEGF was found. In ER beta protein high expression group, the VEGF protein was highly expressed (p<0.01), inverse relationship was also found between ER alpha and VEGF. In univariate analysis ER alpha, ER beta and VEGF levels had prognostic value for both relapse-free survival and overall survival (p<0.05). However, in a multivariate study, ER beta and ER alpha protein levels lost the prognostic value either to relapse-free survival or to overall survival. Only VEGF levels acted as an independent prognostic factor to disease-free survival. The result suggested that ER beta protein may have important prognostic value in human breast cancer patients. VEGF expression may be mediated through different ER subtypes.

Adult↗