摘要:

Polymerase chain reaction (PCR) technique is widely used in the diagnosis of lymphoma, and PCR amplification products are typically detected by polyacrylamide gel electrophoresis (PAGE). However, the identification of small clonal populations, or the distinction of clonal PCR products in a polyclonal milieu remains difficult, requiring technically demanding alterations to gel analysis. This study describes an alternative approach using a capillary electrophoresis (CE) system to produce an accurately sized electropherogram. A variety of patient samples were examined, including solid tissue, peripheral blood, bone marrow aspirates, and paraffin-embedded tissue. A total of 28 samples were evaluated by PCR for B-cell clonality by detection of immunoglobulin heavy chain gene rearrangement and 29 samples for T-cell clonality by detection of T-cell gamma locus gene rearrangement. Standard 10% PAGE analysis of PCR products was compared with CE. There was a 100% concordance in the assessment of both B-cell and T-cell clonality. Dilution studies with the SUP-B15 cell line showed a detection limit of 0.03% for B-cell clonality and 0.05% for T-cell clonality using CE, versus 0.2% to 1%, respectively for PAGE. Automated, fluorescent analysis of PCR products by CE seems to be at least equally as effective as gel-based analysis for the detection of clonal B-cell and T-cell populations. Moreover, CE offers superior resolution and improved sensitivity, thus representing a significant improvement over traditional gel electrophoretic techniques in these regards.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Clonal expansion of the germinal center B cells of human reactive lymph nodes was analyzed. By micromanipulation, 28 germinal centers were microdissected from three nonneoplastic lymph nodes that had been fixed with formalin. Immunoglobulin heavy chain variable (V) region gene rearrangement was examined by seminested polymerase chain reaction (PCR) using two sets of primers (FR2-J and FR3A-J). An oligoclonal development (one to five clones) was found in each germinal center. Depending on the primer used, four or five (16%) of the germinal centers showed a single rearrangement band. The average number of B-cell clones in each germinal center was approximately 2.5. Next, the authors analyzed 50 endoscopic biopsy specimens from 6 patients with non–mucosa-associated lymphoid tissue (MALT) type gastric lymphoma, 25 patients with chronic gastritis, and 19 patients with nonspecific colitis. In addition to the samples from the 6 patients with malignant lymphoma, 8 of 44 biopsy samples (18.2%) from patients diagnosed as having chronic gastritis or nonspecific colitis showed one or two amplified bands. These results indicate that PCR analysis of immunoglobulin heavy chain V region gene rearrangement in small biopsy specimens could be misleading, causing overdiagnosis of reactive lymphoid tissue as B-cell clonal proliferation.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

This study describes a new case of Ewing sarcoma (ES)-peripheral primitive neuroectodermal tumor (pPNET) with unusual phenotype and fusion gene structure. The tumor located in the inguinal area of a 15-year-old boy showed a highly aggressive behavior with hematogenous metastases after intensive chemotherapy and bone marrow transplant, causing death 28 months after diagnosis. The tumor displayed a clear cell pattern, and several neuroectodermal markers proved positive both in the original tumor and in xenografts. This neuroectodermal character was confirmed by electron microscopy. Moreover, cytogenetically the tumor has an unusual chromosomal rearrangement, t(2;22)(q13;q22),t(3;18)(p21;q23), representing a newEWS-FEVfusion type in which exon 7 ofEWSgene is fused with exon 2 ofFEVgene. This is the third published study of an ES-pPNET showingEWS-FEVfusion described, but it is the first study of a tumor with the aforementioned fusion points. These findings support the genetic and morphologic heterogeneity existing within the group of ES-pPNET tumors.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

The reliability of the Hybrid Capture II (HC-II; Digene, Silver Spring, MD, U.S.A.) assay was tested in detecting 18 human Papillomavirus (HPV) types for the screening of cervical lesions. Cytology, HPV testing, colposcopy, and biopsy were used to monitor 204 women with normal smears at the first entry. The median follow-up was 15 months (range, 4–27 months). The primary endpoint was clinical progression defined as the presence of a cervical intraepithelial lesion at the biopsy. In the patient population of 204 HPV-infected women, 81 (39.7%) had a persistent HPV infection at two or three examinations with a final histologic diagnosis of 14 high-grade and 13 low-grade squamous intraepithelial lesions (SIL) within 4 to 22 months. Women with regressive HPV infection did not develop any lesion during the same period. The evaluation of the viral load of high-risk HPV by the HC-II did not represent a sensitive approach to predict the persistence or the apparition of high-grade lesions. Thus, persistent high-risk HPV infection detected with HC-II represents a reliable tool to select populations at risk for the development of high-grade cervical lesions.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

A single-tube real-time nested polymerase chain reaction (PCR) was developed to detect human Papillomavirus (HPV) DNA in a closed tube system. The oligonucleotide primers MY09/MY11 and GP5+/GP6+ were included in contiguous reactions, thus eliminating the need to transfer first round PCR product into a second tube. The sensitivity and specificity of the optimized single-tube nested PCR were comparable with that achieved by two separate reactions on a conventional thermal block system using serial dilutions derived from plasmids containing DNA of 20 HPV types. A minimum of 10 copies of HPV types 11 and 16 DNA could be detected by both systems. In clinical samples, HPV types 1A, 2, 3, 5, 6–8, 10, 11, 14, 16, 17, 18, 20, 31, 33, 35, 39, 45, 49, 50, 52–54, 57, 62, 66, 70, CP8304 and LVX82/MM7 could be detected by both PCR methods. A total of 145 samples collected from patients were tested for the presence of HPV DNA with the two PCR systems: 124 (86.1%) of 144 samples gave concordant results in both assays. The HPV DNA positive PCR amplicons were typed and concordant results were obtained in 47 of 67 positive samples tested in both amplicons. In samples containing multiple HPV types at least one type was common to both amplicons.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Cytokines such as tumor necrosis factor (TNF)-&agr; and Interleukin (IL)-10 play significant roles in autoimmunity and transplantation tolerance. Allelic polymorphisms that occur in the regulatory regions of these cytokine genes are closely associated with acute and chronic transplant rejection. The presence of a G-to-A polymorphism at position −308 in the promoter region of the TNF-&agr; gene can increase transcription six-to sevenfold. Likewise, the G-A polymorphism at position −1082 of the IL-10 promoter results in lower levels of IL-10 protein. Accordingly, a genotype that dictates the production of high levels of TNF-&agr; with low IL-10 capabilities is most likely to generate an inflammatory environment that is less receptive to the transplant. The potential for determining a patient's haplotype before transplantation may be an effective way of monitoring the post-transplant status of such patients. A variety of methodologies that address the detection of mutations have been used both in research and clinical diagnostic tests. This study analyzes the genetic variations in cytokines using two methodologies: the traditional allele-specific oligonucleotide (ASO) polymerase chain reaction (PCR) and the newer and more flexible Invader technology. The sensitivity and specificity of the Invader assay for simultaneous investigation of multiple targets makes it a useful tool in such analyses.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

Promoter methylation represents an important mechanism for silencing gene expression in higher eukaryotes. To study methylation of the promoter of the tumor suppressor p16INK4a, a fast and simple method was developed that, in contrast to previous studies, relies on the positive display of methylated sites (PDM). The method is based on bisulfite treatment of DNA, polymerase chain reaction (PCR)-amplification of the modified DNA and restriction digest of de novo created restriction sites to positively display DNA methylation in a background of unmethylated DNA. Since methylated as well as unmethylated DNA is amplified, information on the proportion of both is provided. Using this approach, 33 ductal invasive carcinomas, 4 normal mammary tissues, and 4 cell lines were analyzed for methylation. Methylation in the p16INK4apromoter was detected in 1 of 33 carcinomas (3%) and in 0 of 4 normal tissues. The conclusion is that PDM provides a useful tool in determining the degree and pattern of promoter methylation and is suitable to screen large series of tissue samples.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID

摘要:

When a DNA probe hybridizes a DNA target and generates a G/A mismatch in the probe-target DNA heteroduplex, the mismatch enzyme,mutY, will cut the A base at the site of the mismatch. This specific cleavage at the mismatched A on the known probe will reveal the complementary DNA sequences of the targets. This study shows mismatch cleavage assays identify the complementary sequence of cryptic plasmid target in the extract of chlamydia infected cells in culture. In addition, the specific cleavage at a single base permits differentiation of two sequences with one base difference. This was shown in differentiating the subtypes of human immunodeficiency virus (HIV) type 1. The addition of amines in the assays increases the sensitivity by freeing the target for recycling. The combined assay system of high sensitivity and demonstrated specificity allows further evaluation for direct identification of pathogenic microorganisms in patient samples.

ISSN:1052-9551    

出版商:OVID    

年代:2000

数据来源: OVID