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Biomedical subjects

D Albertson

Publications and source records attributed to D Albertson.

At least 19 recordsLinked to original sources
PubMed2006

A large field CCD system for quantitative imaging of microarrays.

We describe a charge-coupled device (CCD) imaging system for microarrays capable of acquiring quantitative, high dynamic range images of very large fields. Illumination is supplied by an arc lamp, and filters are used to define excitation and emission bands. The system is linear down to fluorochrome densities <<1 molecule/microm2. The ratios of the illumination intensity distributions for all excitation wavelengths have a maximum deviation approximately +/-4% over the object field, so that images can be analyzed without computational corrections for the illumination pattern unless higher accuracy is desired. Custom designed detection optics produce achromatic images of the spectral region from approximately 450 to approximately 750 nm. Acquisition of a series of images of multiple fluorochromes from multiple arrays occurs under computer control. The version of the system described in detail provides images of 20 mm square areas using a 27 mm square, 2K x 2K pixel, cooled CCD chip with a well depth of approximately 10(5) electrons, and provides ratio measurements accurate to a few percent over a dynamic range in intensity >1000. Resolution referred to the sample is 10 microm, sufficient for obtaining quantitative multicolor images from >30,000 array elements in an 18 mm x 18 mm square.

DNA↗
PubMed2005

Fryns syndrome phenotype caused by chromosome microdeletions at 15q26.2 and 8p23.1.

BACKGROUND: Fryns syndrome (FS) is the commonest autosomal recessive syndrome in which congenital diaphragmatic hernia (CDH) is a cardinal feature. It has been estimated that 10% of patients with CDH have FS. The autosomal recessive inheritance in FS contrasts with the sporadic inheritance for the majority of patients with CDH and renders the correct diagnosis critical for accurate genetic counselling. The cause of FS is unknown. METHODS: We have used array comparative genomic hybridisation (array CGH) to screen patients who have CDH and additional phenotypic anomalies consistent with FS for cryptic chromosome aberrations. RESULTS: We present three probands who were previously diagnosed with FS who had submicroscopic chromosome deletions detected by array CGH after normal karyotyping with G-banded chromosome analysis. Two female infants were found to have microdeletions involving chromosome band 15q26.2 and one male had a deletion of chromosome band 8p23.1. CONCLUSIONS: We conclude that phenotypes similar to FS can be caused by submicroscopic chromosome deletions and that high resolution karyotyping, including array CGH if possible, should be performed prior to the diagnosis of FS to provide an accurate recurrence risk in patients with CDH and physical anomalies consistent with FS.

Abnormalities, Multiple↗
PubMed2003

Genome wide array comparative genomic hybridisation analysis of premalignant lesions of the stomach.

BACKGROUND: Gastric cancer is one of the most frequent malignancies in the world, ranking fifth in the Netherlands as a cause of cancer death. Surgery is the only curative treatment for advanced cases, but results of gastrectomy largely depend on the stage of the disease. A better understanding of the mechanisms of progression from a preneoplastic condition through intraepithelial neoplasia to invasive cancer may provide information relevant to designing focused prevention strategies. METHODS: Because the pattern of chromosomal aberrations in precursors of gastric cancer is unclear, 11 gastric polyps with intraepithelial neoplasia (three hyperplastic polyps and eight adenomas) were analysed by microarray comparative genomic hybridisation to study chromosomal instability in precursors of gastric cancer. RESULTS: Chromosomal aberrations were detected in all specimens. Adenomas showed no more chromosomal aberrations than did the hyperplastic polyps. The most frequent aberrations were gain of 7q36 and 20q12, and loss of 5q14-q21 in the adenomas, and loss of 15q11-14, 1p21-31, and 21q11-21.2 in the hyperplastic polyps. The most frequent chromosomal aberration in common to both types was loss of 9p21.3. CONCLUSION: Hyperplastic polyps showed many chromosomal aberrations, confirming that neoplastic transformation can occur in these lesions. These observations are consistent with the existence of two morphologically and genetically distinct pathways to gastric cancer-the hyperplastic polyp pathway and the (intestinal type) adenoma pathway. The relative contribution of each to gastric carcinogenesis in general, and how they compare to patterns of chromosomal aberrations in the more prevalent flat foci of intraepithelial neoplasia remain to be determined.

Adenoma↗
PubMed2001

Stromal-epithelial interactions in the progression of ovarian cancer: influence and source of tumor stromal cells.

Stromal cells are essential for the progression of many cancers including ovarian tumors. Stromal cell-epithelial cell interactions are important for tumor development, growth, angiogenesis, and metastasis. In the current study, the effects of normal ovarian bovine stromal cells on ovarian tumor progression was investigated. The hypothesis tested is that ovarian stromal cells will alter the onset and progression of ovarian tumors. Conditioned medium from normal bovine ovarian surface stromal cells was found to stimulate the growth of normal ovarian surface epithelium and had no effect on the growth of human tumor cell lines SKOV3 and OCC1. Human ovarian cancer cell lines, SKOV3 and OCC1, were injected subcutaneously into nude mice to examine tumor progression. Tumor growth in the nude mice was dramatically reduced when normal ovarian surface stromal cells were co-injected with SKOV3 or OCC1 cells. Similar results were obtained with normal bovine or human ovarian stromal cells. In contrast, irrelevant testicular stromal cells and epithelial cells had no effect on tumor growth in the nude mouse. Histological examination of these tumors revealed a characteristic stromal cell component adjacent to epithelial cell colonies. Sections of these tumors were hybridized with species specific genomic probes using fluorescence in situ hybridization to identify cell populations. Epithelial cells were shown to be of human origin (i.e. SKOV3 or OCC1), but stromal cells were found to be primarily murine in origin (i.e. host tissue). No detectable bovine cells were observed in the tumors after one week post-injection. Results suggest that stromal cells are an essential component of ovarian tumors. Interestingly, normal ovarian stromal cells had the ability to inhibit tumor growth, but were not able to survive long-term incubation at the tumor site. The developing tumor appears to recruit host (i.e. murine) stromal cells to invade the tumor and support its growth. In summary, normal ovarian stromal cells can inhibit ovarian tumor progression and the developing tumors recruit adjacent host stroma to become "tumor stroma". The tumor stroma likely develop an altered phenotype that cooperates with the tumorigenic epithelial cells to help promote the progression of ovarian cancer.

Animals↗
PubMed2001

Integration of cytogenetic landmarks into the draft sequence of the human genome.

We have placed 7,600 cytogenetically defined landmarks on the draft sequence of the human genome to help with the characterization of genes altered by gross chromosomal aberrations that cause human disease. The landmarks are large-insert clones mapped to chromosome bands by fluorescence in situ hybridization. Each clone contains a sequence tag that is positioned on the genomic sequence. This genome-wide set of sequence-anchored clones allows structural and functional analyses of the genome. This resource represents the first comprehensive integration of cytogenetic, radiation hybrid, linkage and sequence maps of the human genome; provides an independent validation of the sequence map and framework for contig order and orientation; surveys the genome for large-scale duplications, which are likely to require special attention during sequence assembly; and allows a stringent assessment of sequence differences between the dark and light bands of chromosomes. It also provides insight into large-scale chromatin structure and the evolution of chromosomes and gene families and will accelerate our understanding of the molecular bases of human disease and cancer.

Chromosome Aberrations↗
PubMed1998

Positional cloning of ZNF217 and NABC1: genes amplified at 20q13.2 and overexpressed in breast carcinoma.

We report here the molecular cloning of an approximately 1-Mb region of recurrent amplification at 20q13.2 in breast cancer and other tumors and the delineation of a 260-kb common region of amplification. Analysis of the 1-Mb region produced evidence for five genes, ZNF217, ZNF218, and NABC1, PIC1L (PIC1-like), CYP24, and a pseudogene CRP (Cyclophillin Related Pseudogene). ZNF217 and NABC1 emerged as strong candidate oncogenes and were characterized in detail. NABC1 is predicted to encode a 585-aa protein of unknown function and is overexpressed in most but not all breast cancer cell lines in which it was amplified. ZNF217 is centrally located in the 260-kb common region of amplification, transcribed in multiple normal tissues, and overexpressed in all cell lines and tumors in which it is amplified and in two in which it is not. ZNF217 is predicted to encode alternately spliced, Kruppel-like transcription factors of 1,062 and 1,108 aa, each having a DNA-binding domain (eight C2H2 zinc fingers) and a proline-rich transcription activation domain.

Amino Acid Sequence↗
PubMed1998

Dermatomyositis: a dermatology-based case series.

BACKGROUND: Dermatomyositis is associated with significant morbidity and occasional mortality. Currently there is no consensus on treatment for patients with dermatomyositis. OBJECTIVE: Our purpose was to review the clinical features and response to therapy of patients with dermatomyositis and compare these data with previous series of patients with dermatomyositis/polymyositis. METHODS: Clinical characteristics of 65 patients seen during a 10-year period were reviewed retrospectively. Twenty-one of these patients were enrolled in a prospective, uncontrolled study of treatment with high-dose prednisone followed by slow tapering. RESULTS: Clinical features were similar to those previously described; however, muscle strength at diagnosis was on average greater in patients in this series than in patients previously reported. Malignancy was present in 5 of 43 adult patients (12%), but was not found in patients with juvenile dermatomyositis. Another connective tissue disease was present in 19% of patients. Twelve patients had dermatomyositis sine myositis. Eighteen of 21 patients (85%) in the prednisone study group had resolution of myositis. CONCLUSION: Patients with dermatomyositis in this series had less active myositis at presentation, but were otherwise similar to patients with dermatomyositis/polymyositis previously reported. Treatment with high-dose daily prednisone followed by slow tapering was effective.

Adult↗
PubMed1996

cec-1, a soma-specific chromobox-containing gene in C. elegans.

The chromo domain is a phylogenetically conserved sequence motif which was identified as a region of homology between the repressor protein Pc and the heterochromatin constitutive protein HP1 of Drosophila. The specific function of the chromo domain is not yet understood, but it seems to be required for protein-protein interactions in chromatin-associated complexes. Here, we present a new chromobox-containing gene from Caenorhabditis elegans (cec-1). It encodes a nuclear protein that is present in all somatic cells from the 50- to 80-cell stage on throughout development and in adult animals. No cec-1 protein was detected in the cells of early embryos, in germ cells, and in their precursor cells Z2 and Z3. cec-1 mRNA, however, is already present in all the blastomeres of early embryos. Immunolocalization experiments revealed a homogeneous distribution of CEC-1 within interphase nuclei, while during mitosis CEC-1 seems to dissociate from the condensing chromosomes. The expression pattern of the cec-1 gene suggests that it may represent a new regulatory gene in C. elegans.

Amino Acid Sequence↗