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S J Miller

Publications and source records attributed to S J Miller.

At least 73 records · Page 4Linked to original sources
PubMed1997

Pain management guidelines: implications for managed care--a roundtable discussion.

One of the most important concerns of patients with cancer, particularly those with metastatic disease, is "Will I be in constant pain?" This is a similar concern voiced by patients with late-stage human immunodeficiency virus infection. The management of chronic pain has enormous implications on a patient's ability to function and on his or her quality of life. In June 1996, Medical Interface convened a panel of experts in Chicago to discuss pain management therapies, guidelines, and how these issues will affect, and be affected by, the managed care environment.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Cell-type-specific modulation of PDGF-B regulatory elements via viral enhancer competition: a caveat for the use of reference plasmids in transient transfection assays.

The human platelet-derived growth factor-B (PDGF-B) gene has been shown to display a wide range of levels of mRNA transcription in a variety of cell types. Functional analyses of PDGF-B gene expression have begun to reveal intricate, cell-type-specific regulatory mechanisms involving multiple control elements. We have previously isolated and characterised several elements involved in the control of human PDGF-B gene expression in the JEG-3 choriocarcinoma cell line and in the breast cancer-derived cell line, ZR-75. Assessment of the positive or negative regulatory contributions of these elements was carried out using transient transfection assays. Such studies routinely require the inclusion of a reference plasmid in order to determine transfection efficiency. Here we show that competition for regulatory factors occurs in transfected cells between viral enhancers and elements regulating PDGF-B gene transcription. A frequently used reference plasmid which utilises the SV40 promoter and enhancer region to drive expression of a beta-galactosidase reporter gene was found to severely repress the activity of a co-transfected reporter construct containing the PDGF-B promoter and its intronic enhancer in JEG-3 cells. This competition was localised to the enhancer region of the SV40 regulatory sequences and surprisingly, the effect was reversed in ZR-75 cells; where increasing the amount of reference plasmid strongly stimulated the activity of the PDGF-B construct. These results imply that the same intronic region which functions equally well as an enhancer in two distinct cell-types, may operate in response to different transcription factor complements. Furthermore, this data demonstrates that the choice of reference plasmid and its quantitative use can be a crucial factor when examining putative regulatory elements by transient transfection methods.

Chloramphenicol O-Acetyltransferase↗
PubMed1996

Cloning and functional characterization of the gene encoding the TFIIIB90 subunit of RNA polymerase III transcription factor TFIIIB.

The yeast RNA polymerase III (pol III) general transcription factor TFIIIB is composed of three subunits; the TATA-binding protein (TBP)1, the TFIIB-related factor (BRF1), and a third factor termed TFIIIB90 or B". Here we report the purification of yeast TFIIIB90, cloning of the gene encoding TFIIIB90, and reconstitution of TFIIIB from recombinant polypeptides. The TFIIIB90 open reading frame encodes a 68-kDa polypeptide and has no obvious similarity to any other known protein sequences. The gene encoding TFIIIB90 is essential for viability of yeast. Using recombinant TFIIIB subunits, we found that TFIIIB90 interacts weakly with TBP in the absence of BRF1, and that this interaction is enhanced at least 25-fold by BRF1. In addition, TFIIIB90 showed pol III specificity as it could not interact with the pol II-specific TFIIB-TBP-DNA complex. To localize the regions of the TBP-DNA complex that interact with BRF1 and TFIIIB90, we tested whether the pol II factors TFIIA and TFIIB interfered with the binding of BRF1 and TFIIIB90 to TBP-DNA. Our results suggest that the binding sites for BRF1 and TFIIIB90 on TBP-DNA both overlap the binding sites for TFIIA and TFIIB.

Amino Acid Sequence↗
PubMed1996

p53 and translational control.

The tumor suppressor p53 plays a role in mediating a G1 arrest (for example, in response to DNA damage), in the cellular commitment to apoptosis and in suppression of transformation. The mechanism of action of p53 in each of these biological outcomes is likely to be overlapping. Current data indicate that p53 functions as a sequence specific transcriptional activator. p53 can also repress transcription from certain promoters. One way in which p53 mediates a G1 arrest after DNA damage appears to be clear. Cells exposed to ionizing radiation show elevated levels of p53 protein. The increase in p53 levels is thought to be responsible for the increase in the cyclin-dependent kinase (cdk) inhibitor p21 mediated through the p53 binding sites in the p21 promoter. With regard to the ability of p53 to suppress transformation, there is data suggesting that p53 functions other than, or in addition to, its transcriptional activation function may be necessary. Similar data exist for p53-dependent apoptosis. Recently a role for p53 at another level of gene regulation, namely, translational regulation has been proposed. p53 associates with various components of the translation machinery and has been implicated in the translational regulation of both the p53 and CDK4 mRNAs. Here we will summarize the evidence suggesting a role for p53 in translation and how this regulation might be achieved.

Gene Expression Regulation↗
PubMed1996

Identification of a specific DNA region required for enhanced transcription of HER2/neu in the MDA-MB453 breast cancer cell line.

Overexpression and/or amplification of the HER2/neu gene has been shown in roughly 30% of breast cancer patients. Increased levels of HER2/neu mRNA in some breast cancer cell lines is partially caused by increased gene transcription. In MDA-MB453 human breast cancer cells, an activated trans-acting factor is involved in the increased transcription of HER2/neu by mediating its effects through a specific DNA region in the HER2/neu promoter. A methylation interference experiment showed a novel sequence for protein-DNA interactions. Three polypeptides of approximately 110, 70, and 35 kD interact with this DNA element. This region of the human HER2/neu promoter is highly conserved in the rat and mouse promoters and was shown to be capable of mediating transcriptional trans-activation in HER2/neu-overexpressing MDA-MB453 cells while having little effect in a control cell line that expresses basal levels of HER2/neu. Knowledge on interactions between this DNA element and nuclear protein factors may help us better understand the molecular mechanisms regulating HER2/neu overexpression in breast cancer cells.

Animals↗
PubMed1996

Allele-specific in situ hybridization (ASISH) analysis: a novel technique which resolves differential allelic usage of H19 within the same cell lineage during human placental development.

Precursory studies of H19 transcription during human foetal development have demonstrated maternally derived monoallelic expression. Analyses in extra-embryonic tissues, however, have been more equivocal, with discernible levels of expression of the paternal allele of H19 documented in the first trimester placenta. By refining the in situ hybridization technique we have developed an assay to enable the functional imprinting status of H19 to be determined at the cellular level. This assay involves the use of oligonucleotide DNA probes that are able to discriminate between allelic RNA transcripts containing sequence polymorphisms. Biallelic expression of H19 is confined to a subpopulation of cells of the trophoblast lineage, the extravillous cytotrophoblast, while the mesenchymal stroma cells maintain the imprinted pattern of monoallelic expression of H19 throughout placental development. This data demonstrates that the low level of paternal H19 expression previously detected in normal human placenta is not due to a random loss of functional imprinting, but appears to result from a developmentally regulated cell type-specific activation of the paternal allele. In addition, biallelic expression of H19 does not seem to affect the functional imprinting of the insulin-like growth factor II gene, which is monoallelically expressed at relatively high levels in the extra-villous cytotrophoblasts. These results imply that the allelic usage of these two genes in normal human placental development may not be directly analogous to the situation previously documented in the mouse embryo.

Alleles↗
PubMed1995

An Inr-containing sequence flanking the TATA box of the human c-sis (PDGF-B) proto-oncogene promoter functions in cis as a co-activator for its intronic enhancer.

High-level activity of the human PDGF-B promoter in choriocarcinoma cell lines depends upon an atypical, intronic enhancer-like element which does not function with heterologous promoters tested. An extensive series of mutant PDGF-B promoter-driven constructs identified a sequence flanking the TATA box which is required specifically for enhancer-mediated transcription in human choriocarcinoma cell lines. This element, which we here term an enhancer-dependent cis co-activator (EDC) contains an Inr (initiator) consensus sequence upstream of the TATA box which is required, but not sufficient for its function. Requirement for the EDC is cell type-specific, since it was dispensable for enhancer-mediated transcription in a human breast cancer cell line. Although it lies within the region defined, the TATA box itself is not required for EDC function, or for basal promoter function which may derive from a second Inr-like sequence situated at the transcriptional start site. These observations indicate that interactions between some promoter and enhancer elements may be more complex than that generally described for 'classical' enhancer systems and may suggest an additional function for the initiator motif.

Base Sequence↗
PubMed1995

Paternally derived H19 is differentially expressed in malignant and nonmalignant trophoblast.

The paternal allele of the H19 gene has been shown to be transcriptionally inactive in the developing human embryo. Using reverse transcription PCR and RNase protection assays, we demonstrate that expression of H19 is predominantly, but not exclusively, from the maternal allele in the human placenta. In situ hybridization analysis shows strong expression of the H19 gene in eight complete hydatidiform moles, hyperplastic tissues consisting of trophoblasts which contain only paternally derived genetic material, indicating that H19 is not functionally imprinted in this tissue. H19, a putative growth suppressor, is oppositely imprinted to the neighboring insulin-like growth factor II (IGF2) gene and an up-regulation of IGF2 expression has been linked previously to a down-regulation of H19 expression in the progression to Wilms' tumor. Two cases of complete hydatidiform mole which progressed to choriocarcinoma show high levels of expression of both H19 and IGF2. The choriocarcinomas which developed from these complete hydatidiform moles showed similar expression of IGF2 but a decreased number of H19-positive cells, which may reflect selection for cells expressing IGF2 and against those expressing H19 in this tissue.

Alleles↗
PubMed1995

p53-dependent repression of CDK4 translation in TGF-beta-induced G1 cell-cycle arrest.

Transforming growth factor beta 1 (TGF-beta 1) can cause a cell-cycle arrest in G1. Inhibition of cyclin-dependent kinase 4 (cdk4) synthesis plays a significant role in the mechanism by which this cytokine causes G1 growth arrest. Deregulated expression of cdk4 confers resistance to TGF-beta 1. Here, we show that TGF-beta 1 down-regulates cdk4 expression by inhibiting its translation. Moreover, mutant p53 confers resistance to TGF-beta 1 by interfering with the down-regulation of cdk4 in response to the cytokine. In contrast, we demonstrate that wild-type p53 represses the translation of CDK4. Regulation of cdk4 synthesis by both p53 and TGF-beta 1 is mediated by the 5'-untranslated region of the CDK4 message. Thus, regulation of CDK4 translation may be involved in control of G1 progression by p53.

Base Sequence↗
PubMed1995

A modified Chrisman-Snook procedure for reconstruction of the lateral ligaments of the ankle: review of 18 cases.

The outcome of 18 ankles of 16 patients who underwent a modification of the Chrisman-Snook lateral ligamentous reconstruction was analyzed. The modification described herein attempts a more anatomic reconstruction of the calcaneofibular ligament, while the anterior talofibular ligamentous reconstruction remains unchanged. All patients were evaluated before and after surgery by physical examinations and stress inversion radiographs were taken to measure the degree of talar tilt. Additional postoperative assessment consisted of a questionnaire, inversion and eversion isokinetic strength measurements, subtalar joint inversion stress radiographs (stress Brodén's views), and a hop test to assess ankle confidence. An average preoperative talar tilt of 13.7 degrees was reduced to an average of 2.3 degrees after surgery. Post-operative subtalar stress radiographs revealed an average of 2.8 degrees of subtalar tilt compared with the "normal" average of 7.2 degrees in the nonoperative ankles. While no ankles were found before surgery to have a 3+ anterior drawer sign, 11 ankles had 3+ inversion laxity. Excessive inversion laxity, which can occur through both the ankle and subtalar joints, more than anterior drawer laxity, may appear to be the primary determinant of functional ankle instability in the chronic setting. We recommend subtalar stress radiographs, in addition to routine talar stress radiographs, to quantify the relative contributions of each of these joints to inversion laxity in a symptomatic patient to guide appropriate treatment. The described procedure will anatomically stabilize both joints to inversion stress.

Adolescent↗
PubMed1994

How a New York cardiac surgery program uses outcomes data.

In New York State, a risk-adjusted outcomes system has been used by the Department of Health to monitor all cardiac operations since January 1989. Hospital-specific and physician-specific results are published annually. In this report we describe the experience of one hospital in New York State whose results showed a higher than expected surgical mortality. Staff reactions were initially skeptical, and case reviews found no quality-of-care problems. However, a different approach using statistical analysis of the detailed case-specific outcomes data was more revealing. The excess mortality was localized to patients having high-acuity, emergency coronary artery bypass grafting, particularly those who had suffered a preoperative acute myocardial infarction less than 6 hours before, those who were in shock, or those who were in a hemodynamically unstable condition. The staff responded with a focused effort to optimize the management of these patients, resulting in zero mortality for emergency coronary artery bypass grafting during the following year. In the process, staff from all departments joined together in a more collaborative approach to the cardiac surgery program. Outcomes data can be useful for effecting program improvement if comparable norms and open access for flexible analysis are available.

Cardiac Surgical Procedures↗