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Biomedical subjects

J M Lancaster

Publications and source records attributed to J M Lancaster.

23 records · Page 2Linked to original sources
PubMed1986

Intraspinal pathways taken by sublaminar wires during removal. An experimental study.

The neurological complications of segmental sublaminar stabilization that have been reported by other authors led us to perform a cineradiographic study of the pathways in the spinal canal that were taken by wires as they were being removed. The single wires were removed by pulling on the wire while keeping the wire perpendicular to the lamina; by winding the wire on the wire-extractor, with the wire being kept as nearly parallel with the lamina as possible (the roll-up technique); or by pulling on the wire while keeping the wire parallel with the lamina. During removal, thirty-four single wires conformed to the lamina and forty-one single wires compressed the dura. The roll-up technique caused the most erratic pathways. Double wires, although they were removed together, assumed independent pathways unless a wire-extractor guide was used. These findings suggest that the removal of sublaminar wires may cause dural compression in the clinical situation.

Bone Wires↗
PubMedDate not supplied

Aberrant splicing of the TSG101 tumor suppressor gene in human breast and ovarian cancers.

OBJECTIVE: To determine whether large deletions or other alterations in the putative tumor suppressor gene TSG101 play a role in the molecular pathogenesis of breast and ovarian cancers. METHODS: Expression of TSG101 transcripts was examined in breast and ovarian cancers using the reverse transcriptase-polymerase chain reaction (RT-PCR), and selected transcripts were sequenced. Southern blot analysis was performed to determine whether there were genomic deletions in the TSG101 gene, and Northern blot analysis was used to examine the relative abundance of various transcripts. RESULTS: All the cancerous and normal breast tissue examined expressed full length 1145 base pair (bp) TSG101 transcripts. Additional truncated transcripts were seen using the RT-PCR in 57 (64%) of 89 primary breast cancers, 1 (20%) of 5 breast cancer cell lines, 3 (50%) of 6 normal breast tissues, 16 (64%) of 25 primary ovarian cancers and 1 (33%) of 3 ovarian cancer cell lines. Only the primary breast (21%) and ovarian (24%) cancers had three or more truncated transcripts. None of the normal tissues or cell lines examined had more than two aberrant transcripts. DNA sequencing revealed that the most commonly expressed truncated transcript arises because of loss of 902 bp between codons 153 and 1055. Only full length TSG101 transcripts were seen on Northern blot analysis of breast cancer cell lines, however. There was no evidence of genomic deletions in the TSG101 gene on Southern blot analysis. CONCLUSION: Truncated TSG101 transcripts that probably represent splice variants are present in some breast and ovarian cancers, but there is no evidence to suggest that loss of this putative tumor suppressor gene plays a role in the molecular pathogenesis of these cancers.

Base Sequence↗
PubMedDate not supplied

High expression of insulin-like growth factor binding protein-2 messenger RNA in epithelial ovarian cancers produces elevated preoperative serum levels.

The molecular etiology of epithelial ovarian cancer remains unclear. Using microarray expression analysis, we recently reported that expression of the insulin-like growth factor binding protein-2 (IGFBP-2) gene is elevated in advanced epithelial ovarian cancers. The aim of this study was to further delineate the role of IGFBP-2 in the pathoetiology of epithelial ovarian cancer and determine if elevated ovarian cancer IGFBP-2 gene expression is reflected in serum. Relative IGFBP-2 expression was measured using quantitative real-time polymerase chain reaction in 113 epithelial ovarian cancers and 6 normal ovarian surface epithelial samples. Preoperative serum IGFBP-2 levels were measured by radioimmunoassay in 84 women (42 ovarian cancers, 26 benign gynecological conditions, and 10 healthy female controls). Ovarian cancers demonstrated 38-fold higher mean IGFBP-2 expression than normal ovarian epithelium (P < 0.01). Serum IGFBP-2 levels were elevated in women with early- and advanced-stage ovarian cancer compared to controls and patients with benign gynecological conditions (P = 0.05 and P < 0.01, respectively). Epithelial ovarian cancers express high levels of IGFBP-2 relative to normal ovarian epithelium, and this is associated with elevated serum IGFBP-2 levels compared to both normal controls and patients with benign gynecological disease. Our findings provide further support that the insulin-like growth factor pathway plays a significant role in epithelial ovarian cancer pathogenesis. Further, IGFBP-2 may represent an additional serum biomarker with utility in detection and monitoring of epithelial ovarian cancer.

Adenocarcinoma, Clear Cell↗
PubMedDate not supplied

Identification of genes associated with ovarian cancer metastasis using microarray expression analysis.

Although the transition from early- to advanced-stage ovarian cancer is a critical determinant of survival, little is known about the molecular underpinnings of ovarian metastasis. We hypothesize that microarray analysis of global gene expression patterns in primary ovarian cancer and metastatic omental implants can identify genes that underlie the metastatic process in epithelial ovarian cancer. We utilized Affymetrix U95Av2 microarrays to characterize the molecular alterations that underlie omental metastasis from 47 epithelial ovarian cancer samples collected from multiple sites in 20 patients undergoing primary surgical cytoreduction for advanced-stage (IIIC/IV) serous ovarian cancer. Fifty-six genes demonstrated differential expression between ovarian and omental samples (P < 0.01), and twenty of these 56 differentially expressed genes have previously been implicated in metastasis, cell motility, or cytoskeletal function. Ten of the 56 genes are involved in p53 gene pathways. A Bayesian statistical tree analysis was used to identify a 27-gene expression pattern that could accurately predict the site of tumor (ovary versus omentum). This predictive model was evaluated using an external data set. Nine of the 27 predictive genes have previously been shown to be involved in oncogenesis and/or metastasis, and 10/27 genes have been implicated in p53 pathways. Microarray findings were validated by real-time quantitative PCR. We conclude that gene expression patterns that distinguish omental metastasis from primary epithelial ovarian cancer can be identified and that many of the genes have functions that are biologically consistent with a role in oncogenesis, metastasis, and p53 gene networks.

Bayes Theorem↗