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Results for “Microdissection”

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At least 325 records · Page 18Linked to original sources

PubMed2003

[Cloning associated genes using microdissection-cDNA PCR-SSH in gastric dysplasia].

OBJECTIVE: To construct cDNA subtracted libraries from gastric dysplasia and further screen differentially expressed genes. METHODS: Relatively pure dysplasia and normal tissue were procured by manual microdissection, and amplified by cDNA-PCR, which was used to carry on for suppression subtractive hybridization (SSH). Subtracted cDNA fragments were linked with vector, cloned, screened, sequenced, and made homologous search. Differentially expressed fragments were verified by dot hybridization. RESULTS: Two subtracted cDNA libraries were constructed. Among 26 sequenced clones, 15 fragments corresponded to known genes, 3 fragments were known EST and 8 fragments were unknown EST (GenBank BQ164614-BQ164616, BQ291516-BQ291520). Fifteen fragments were verified to be differentially expressed in gastric dysplasia. CONCLUSIONS: Subtracted cDNA libraries from gastric dysplasia are constructed using combination of microdissection-cDNA PCR and SSH setup in our laboratory. Some fragments have been screened and verified to help to search for novel associated genes with gastric carcinogenesis.

Cloning, Molecular↗

PubMed2005

[Preliminary biomarker related to nasopharyngeal carcinoma filtered from the whole genome expression profiling involved in microdissection nasopharyngeal tissues].

OBJECTIVE: To filter biomarkers of nasopharyngeal carcinoma (NPC) by constructing the homogenesis tissue gene expression profiling with the whole human genome GeneChip. METHODS: The epithelium cells of the homogenesis NPC and the pure nasopharyngeal normal tissues microdissected from nasopharyngeal biopsy which was preserved in the RNAlater were used to isolate RNA and then to harvest the aRNA through in vitro transcription, and aRNA prober was labled to hybridize to HG-U133. plus 2.0, so the expression profiling of each homogenesis tissue could be constructed. RESULTS: Some candidate biomarker genes related to the tumorigenesis of NPC had been filtered by comparing the expression profiling of NPC samples with the expression profiling of normal nasopharyngeal epithelia samples. Any genes regarding the metastasis of NPC might have been selected by comparing the expression profiling of no-metastasis samples with those of the metastasis samples. CONCLUSION: Using the whole genome GeneChip to construct the expression profiling for the microdissected homogenesis tissue is effective to filter the candidate biomarker genes.

Adult↗

PubMed2005

Comparative genomic hybridization using DNA from laser capture microdissected tissue.

Comparative genomic hybridization (CGH) is a powerful screening technique that can identify regions of gain and loss within the whole genome in a single experiment. The combination of laser capture microdissection, whole-genome amplification, and CGH permits genomic screening with high specificity and sensitivity. This complement of techniques has enabled analysis of focal regions and subpopulations of cells within a tissue, which has previously been difficult, providing insight into disease progression and heterogeneity. This chapter outlines the techniques involved in producing labeled probes from DNA extracted from laser capture microdissected material and the methods for hybridization of these probes to metaphase chromosomes. This protocol can also be applied to the preparation of probes for CGH arrays.

DNA, Neoplasm↗

PubMed2005

Combined laser-assisted microdissection and short tandem repeat analysis for detection of in situ microchimerism after solid organ transplantation.

Following the transplantation of a solid organ leukocytes of donor origin migrate out of the organ, contributing to a chimeric blood cell population ("peripheral microchimerism"). At the same time, leukocytes and pluripotent precursor cells of the recipient migrate into the organ, creating an "in situ microchimerism." A method is described for the identification of cells with the recipient's genotype in the transplanted organ by combining laser-assisted microdissection and short tandem repeat analysis. The microdissection allows the contamination-free isolation of morphologically and immunohistochemically characterized cells or groups of cells from histological tissue sections. The subsequent analysis of highly polymorphic short tandem repeats enables unequivocal genotyping in nearly all donor-recipient instances. Employing this new methodological approach, we could identify in individual transplanted organs differentiated parenchymal cells of recipient's origin, which most probably are derived from circulating precursor cells from the bone marrow.

Humans↗

PubMed2005

Heterochromatin and chromosome evolution: a FISH probe of Cebus apella paraguayanus (Primate: Platyrrhini) developed by chromosome microdissection.

Neotropical Primate karyotypes are highly variable, particularly in the heterochromatic regions, not only regarding the amount of heterochromatin, but also the composition. G and C banding and FISH techniques provide useful information to characterize interspecific relationships. We used chromosome microdissection to develop a FISH probe of the chromosome 11 heterochromatic block (11qHe+) of Cebus apella paraguayanus (CAPp). Fragments of the 11qHe+ microdissected from fibroblast cell culture were collected in a PCR tube, amplified by degenerate oligonucleotide primer-PCR and subsequently labeled. The specificity of the FISH probe was confirmed in metaphases of some Ceboidea species. Signals were located in the He+ of chromosomes 4, 11, 12, 13, and 19 of CAPp and in the He+ of chromosomes 4, 12 and 13 of C. a. nigritus (CAPn); no signals were observed when other Ceboidea species were analyzed. We propose that the heterochromatin observed in CAPp and CAPn is specific for these species. We consider this C. apella heterochromatin identity as a possible key for the interpretation of chromosomal evolution in these Ceboidea.

Animals↗

PubMedDate not supplied

Analysis of the HER2/neu gene amplification in microdissected breast cancer tumour samples.

The HER2/neu oncogene has been reported to be amplified in > 20% of invasive ductal carcinomas. In order to investigate the HER2/neu status in pure populations of breast cancer cells, a laser capture microdissection (LCM) system was used. Formalin-fixed paraffin-embedded breast tissue areas corresponding to normal ducts, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) were microdissected and genomic DNA was isolated by a modified proteinase K- phenol extraction method and subjected to PCR for HER2/neu analysis. One hundred % concordance for detection of the HER2/neu gene amplification was found between immunohistochemistry and PCR used in combination with LCM. Our results indicated that LCM is a powerful technique for isolating pure populations of cells from paraffin-embedded tissue sections and that these cells can be used to study genomic alterations at the DNA level.

Base Sequence↗

PubMedDate not supplied

Laser microdissection and microsatellite analysis of colorectal adenocarcinomas.

BACKGROUND: Microsatellite instability (MSI) is an important marker in colorectal cancer. The analysis may be difficult if the tumour is heterogeneous or only scarce material is available. The aim of this study was to apply laser microdissection (LMD) to MSI analysis in an attempt to allow diagnosis in these situations. MATERIALS AND METHODS: Twenty-two primary tumours and eight lymph node metastases from twenty patients were laser microdissected and MSI analysis was performed with an optimised multiplex PCR. Differences in allelic size between tumour and blood were evaluated to determine the MSI status. RESULTS: The method proved efficient in as little as 4,000 microm3 formalin-treated and paraffin-embedded tumour tissue. The result of microsatellite analysis was independent of sample location in the primary tumour and its metastasis. CONCLUSION: LMD followed by a multiplex PCR is a useful method for MSI analysis in cases of tumour heterogeneity and scarce tumour material.

Adenocarcinoma↗

PubMed1997

Maternal balanced translocation leading to partial duplication of 4q and partial deletion of 1p in a son: cytogenetic and FISH studies using band-specific painting probes generated by chromosome microdissection.

A 9-month-old boy with pre- and post-natal growth retardation, microcephaly, plagiocephaly, and several minor anomalies had the initial karyotype: 46,XY,der(1)t(1;?) (p36.1;?). Further analysis showed that the der(1) was derived from an unfavorable segregation of a maternal complex chromosome rearrangement, i.e., 46,XX,der(1)t(1;?) (p36.1;?), der(4)t(4;?)(q?;?). Whole chromosome fluorescence in situ hybridization (FISH) and chromosome microdissection were used to clarify the maternal karyotype as: 46,XX,der(1)t(1;4)(4qter-->4q33::1p36.13-->1qter),der( 4)t(1;4)inv(4)(4pter-->4q31.3::1p36.33-->1p36.13::4q33 -->4q31.3::1p36.33-->1pter). Therefore, the karyotype of the boy actually was 46,XY,der(1)t(1;4) (p36.13;q33). Clinical comparison of the patient's clinical findings showed similarities to individuals with partial del(1p) and dup(4q). To our knowledge the above cytogenetic abnormalities have not been described previously. This case further demonstrates the advantages of chromosome microdissection and FISH in the identification of anomalous chromosome regions and breakpoints.

Abnormalities, Multiple↗

PubMed1996

Practical histological microdissection for PCR analysis.

Recovery of cells by histological microdissection is increasingly used for analysis by polymerase chain reaction (PCR) or microchemical techniques. This paper describes techniques of histological microdissection. Sections of archival formalin-fixed, paraffin-embedded tissue up to 15 years old were mounted on plain glass slides. Sections 6-7 microns in thickness stained with toluidine blue were dissected under proteinase K buffer solution, using an electrolytically sharpened tungsten needle in a bacteriological loop-holder and a Leitz mechanical micromanipulator (model M). Detached cell groups were recovered in a silicone-coated pipette tip for PCR analysis after digestion in 25-50 microliters of proteinase K (500/ml) in TRIS-HCl buffer (pH 8.3). Consistent amplification and analysis of microsatellite loci were obtained from 2 microliters of crude lysate using 28-30 cycles of PCR incorporating a 32P 5'-end-labelled primer, electrophoresis under denaturing conditions on 6 per cent polyacrylamide gels, and autoradiographic detection.

Alleles↗

PubMed1998

Distinct cytogenetic alterations in squamous intraepithelial lesions of the cervix revealed by laser-assisted microdissection and comparative genomic hybridization.

BACKGROUND: It has been established that comparative genomic hybridization (CGH) on Papanicolaou-stained cervical smears can be used to identify chromosomal imbalances. METHODS: In this study, the authors identified normal and dysplastic squamous epithelial cells cytologically, eliminated surrounding bacteria or leukocytes by a ultraviolet laser microbeam under microscopic control, and scraped out the cell groups of interest by a microdissection system. In 3 cases of squamous intraepithelial lesions (SIL), a total of 9 samples of dysplastic (n = 6) and nontumorous cells (n = 3) were investigated, each of them consisting of 3-40 cells. The DNA was amplified by degenerate oligonucleotide primed PCR (DOP-PCR) and used for CGH. RESULTS: Analyses of all nontumorous cell groups resulted in fluorescence ratio profiles that showed no deviation from the normal range, confirming that no methodologic artefacts have been produced. The CGH profiles from dysplastic cells, however, showed various chromosomal imbalances affecting six to nine different chromosomes. The most frequent gains in DNA were observed on chromosomes 1p, 2q, 4, and 5, whereas losses were found on chromosomes 6q and 13q. CONCLUSIONS: The results of this study demonstrate the feasibility and reliability of CGH on microdissected cell samples of routinely processed cervical smears. To the authors' knowledge, this is the first study reporting the use of CGH on cervical routine smears. This approach offers the opportunity to investigate sequence copy number changes in small, morphologically well-defined groups of dysplastic cells. It may, therefore, serve as a cytogenetic screening test for identifying chromosomal aberrations in precancerous lesions that are associated with a high risk for progression to invasive cancer.

Chromosome Aberrations↗

PubMed1996

Detection of frequent allelic loss of 6q23-q25.2 in microdissected human breast cancer tissues.

Detection of allelic loss in human breast cancer is hindered by the fact that breast cancer tissues are frequently infiltrated by stromal and inflammatory cells. For this study, we carefully microdissected infiltrating breast cancer tumor cells from contaminating normal cells and analyzed the DNA from these samples for allelic loss on the long arm of chromosome 6 by using a panel of 15 dinucleotide repeat markers. We found 53 of the 66 cases studied (80%) to have allelic loss of either the entire chromosomal arm (37 cases) or a portion of the chromosomal arm (16 cases). One common region that was identified for all tumors with deletions of 6q was the area between markers D6S310/314 and D6S473/255, consistent with a tumor suppressor gene locus at 6q23-6q25.2. The use of tissue microdissection allowed the detection of allelic loss in this chromosomal region in human breast cancer at a much higher frequency than was previously recognized.

Adult↗

PubMed1997

Combined chromosome microdissection and comparative genomic hybridization detect multiple sites of amplification DNA in a human lung carcinoma cell line.

Chromosome microdissection-fluorescence in situ hybridization and comparative genomic hybridization (CGH) were performed in parallel to identify the native location of amplified DNA in a human non-small cell lung cancer (NSCLC) cell line exhibiting a homogeneously staining region (hsr) and double minutes (dmin). The native locations of microdissected DNA from the hsr and dmin were 7p12-13 and 8q24, respectively. Southern analysis revealed coamplification of EGFR (7p12) and MYC (8q24). CGH detected amplification of DNA not only from 7p12-13 and 8q24, but also from 9p24 and 10q22.

Blotting, Southern↗

PubMed2003

Laser-mediated microdissection facilitates analysis of area-specific gene expression in rheumatoid synovium.

OBJECTIVE: Current approaches to analyzing gene expression in rheumatoid arthritis (RA) synovium are based on RNA isolated either from cultured synovial cells or from synovial biopsy specimens. This strategy does not, in general, allow distinction of specific gene expression between cells originating from different synovial areas, due to potential mixture of expression profiles. Therefore, we established the combination of laser-mediated microdissection (LMM) and differential display to analyze profiles of gene expression in histologically defined areas of rheumatoid synovium. The present study was undertaken to establish parameters for this technique and assess its usefulness for gene expression analysis. METHODS: Cryosections derived from RA synovial tissues were used to obtain cell samples from synovial lining versus sublining, using a microbeam laser microscope. RNA was isolated and analyzed by nested RNA arbitrarily primed-polymerase chain reaction (RAP-PCR) for differential display fingerprinting. Differentially expressed bands were cut out, and PCR products were eluted, cloned, and sequenced. Differential expression of identified sequences was confirmed by in situ hybridization and immunohistochemistry analysis. RESULTS: Microdissected sections of RA synovial tissue containing approximately 600 cells yielded enough RNA to produce a reproducible RNA fingerprint pattern. Several genes could be identified as being expressed differentially between the synovial lining and the sublining, and their expression could be confirmed at the messenger RNA and protein levels. CONCLUSION: The combination of LMM and RAP-PCR presents a valuable tool to obtain novel insights into the area-dependent differential regulation of gene expression in RA synovium. Both known and previously unknown genes were revealed with this technique. This study is the first to demonstrate the potential of this analytic strategy in the investigation of a nonmalignant, multifactorial, inflammatory disease.

Arthritis, Rheumatoid↗

PubMed2003

Intraluminal blunt microdissection for angioplasty of coronary chronic total occlusions.

This study describes a new approach to crossing coronary chronic total occlusions using controlled blunt microdissection and its successful application to coronary angioplasty in three patients. After guidewire techniques failed to cross the occlusions, the blunt intraluminal microdissection catheter was deployed. Actuation of a hinged jaw on the catheter distal assembly created a channel for the guidewire through the diseased segment, in the true lumen (a right coronary and a left circumflex artery) and subintimally (a circumflex artery), to allow angioplasty and stenting. Coronary circulation improved from TIMI grade 0 to 3. Angina was relieved in all three cases. Subsequent angiography for two cases, 2 and 19 months after PTCA, respectively, showed restored flow and patent stented regions.

Angioplasty, Balloon, Coronary↗

PubMed2003

Proteomic analysis of immunostained, laser-capture microdissected brain samples.

Proteomic analysis is often performed on homogenized preparations of whole tissues, which does not provide any information about relevant biochemical changes in specific cell types. Laser-capture microdissection (LCM) is a technique that is precise enough to dissect single cells within a tissue section. Phenotypically defined cells of interest may be visualized by immunostaining prior to microdissection. Previously published immunostaining protocols adapted to LCM require the use of very high antibody titers and very short incubation times. This raises the concern that low-abundance antigens would not be detected and that antisera would be rapidly depleted. In addition, protein recovery from samples was not evaluated in most of these studies. Here, we describe an optimized immunostaining method based on immunofluorescence. By comparing two-dimensional electrophoresis (2-DE) results obtained from immunostained LCM brain tissue samples to those obtained from unstained, manually dissected samples, we demonstrated that immunofluorescent staining gave comparable protein recovery and similar resolution of protein spots on 2-DE gels. Moreover, matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry analysis of selected spots from gels derived from control and immunostained LCM samples revealed that the immunostaining process had minimal effect on protein identification. LCM of immunofluorescently labeled tissue sections is a practical and powerful method to perform proteomic studies on specifically defined cell groups.

Animals↗

PubMed2003

Analysis of colorectal tumor progression by microdissection and comparative genomic hybridization.

This investigation aimed to identify patterns of copy number change in colorectal tumor progression from adenoma to liver metastasis. Fifty-three microdissected sub-regions from 17 cases of colorectal cancer were assigned to one of six histopathologically defined categories: coexisting adenoma, tumor above the muscularis layer, tumor within the muscularis layer, tumor extending through the bowel wall to serosal fat, lymph node metastasis, and liver metastasis. Microdissected samples were treated by a microwave processing step and then used as templates for universal PCR amplification. PCR products were fluorophore labeled and subjected to comparative genomic hybridization. Copy number changes were found in all samples, and every chromosome arm (excluding acrocentric short arms) was affected. More losses than gains were detected, but there were no significant differences between the numbers of changes seen in each category. Each individual sample revealed unique changes, additional to those shared within each case. The most frequently observed gains were of X and 12q. The most common losses were of 8p, 16p, 9p, 15q, 18q, and 10q. Nominally significant associations were observed between metastatic tumor and loss of 12q24.1 or 10p13-14, non-metastatic tumor and loss of 8q24.1, tumor extending to serosal fat and loss of 6q24-25 or gain of 4q11-13, tumor extending to serosal fat and metastatic lesions and loss of 4q32-34 or 22q11-12, and adenoma and loss of 15q24. Loss of 4q32-34 remained highly significant after correction for multiple testing. Adenoma was the only category not to show loss of 17p. These data reveal a genetically heterogeneous picture of tumor progression, with a small number of changes associated with advanced disease.

Adenocarcinoma↗

PubMed2004

Laser microdissection reveals regional and cellular differences in GFAP mRNA upregulation following brain injury, axonal denervation, and amyloid plaque deposition.

Astrocytes are one of the major cell types responding to central nervous system injury. Upregulation of the astrocytic intermediate filament molecule glial fibrillary acidic protein (GFAP) is a key event associated with this reaction. To study the response of astrocytes to different types of brain lesions, GFAP mRNA expression was analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in mouse brain following injury, axonal denervation (entorhinal cortex lesion), and amyloid plaque deposition (APP23 transgenic mice). Analysis of tissue areas surrounding a lesion revealed a 21-fold increase of GFAP mRNA in tissue surrounding an injury site, a 6-fold increase in denervated tissue areas, and a 5-fold increase in plaque containing tissue. To this GFAP mRNA increase, astrocytic proliferation and migration as well as an increase of cellular GFAP mRNA expression within astrocytes could have contributed. To determine the degree of GFAP mRNA upregulation in individual astrocytes, an immunofluorescence protocol was developed to harvest astrocytes selectively by laser microdissection and preserve intact RNA. qRT-PCR analysis of GFAP mRNA in microdissected astrocytes revealed an 82-fold increase in astrocytes surrounding an injury site, a 30-fold increase in astrocytes located in a denervation zone, and an 18-fold increase in astrocytes surrounding an amyloid plaque. These data demonstrate that GFAP mRNA is strongly upregulated within individual reactive astrocytes in response to a lesion. Because astrocytic GFAP mRNA upregulation differs among the three lesioning paradigms, we conclude that the lesion type is an important determinant of postlesional astrocytic reactivity.

Animals↗

PubMed2002

Differential gene expression in breast cancer cell lines and stroma-tumor differences in microdissected breast cancer biopsies revealed by display array analysis.

To examine gene-expression patterning in late-stage breast cancer biopsies, we used a microdissection technique to separate tumor from the surrounding breast tissue or stroma. A DD-PCR protocol was then used to amplify expressed products, which were resolved using PAGE and used as probe to hybridize with representative human arrays and cDNA libraries. The probe derived from the tumor-stroma comparison was hybridized with a gene array and an arrayed cDNA library derived from a GCT of bone; 21 known genes or expressed sequence tags were detected, of which 17 showed differential expression. These included factors associated with epithelial to mesenchymal transition (vimentin), the cargo selection protein (TIP47) and the signal transducer and activator of transcription (STAT3). Northern blot analysis was used to confirm those genes also expressed by representative breast cancer cell lines. Notably, 6 genes of unknown function were restricted to tumor while the majority of stroma-associated genes were known. When applied to transformed breast cancer cell lines (MDA-MB-435 and T47D) that are known to have different metastatic potential, DD array analysis revealed a further 20 genes; 17 of these genes showed differential expression. Use of microdissection and the DD-PCR array protocol allowed us to identify factors whose localized expression within the breast may play a role in abnormal breast development or breast carcinogenesis.

Biomarkers, Tumor↗