Search PubMed⌕ Search

Biomedical subjects

R Steele

Publications and source records attributed to R Steele.

At least 19 recordsLinked to original sources
PubMed2000

Hepatitis C virus NS5A protein modulates transcription through a novel cellular transcription factor SRCAP.

Hepatitis C virus NS5A protein transcriptionally modulates cellular genes and promotes cell growth. NS5A is likely to exert its activity in concert with cellular factor(s). Using a yeast two-hybrid screen, we have demonstrated that NS5A interacts with the C-terminal end of a newly identified cellular transcription factor, SRCAP. The authenticity of this interaction was verified by a mammalian two-hybrid assay, in vitro pull-down experiment, and an in vivo coimmunoprecipitation assay in human hepatoma (HepG2) cells. An in vitro transient transfection assay demonstrated that SRCAP can efficiently activate transcription when recruited by the Gal4 DNA-binding domain to the promoter. However, down-regulation of p21 promoter activity by NS5A was enhanced following ectopic expression of SRCAP. Together these results suggest that the interaction of NS5A and SRCAP may be one of the mechanisms by which NS5A exerts its effect on cell growth regulation contributing to hepatitis C virus-mediated pathogenesis.

Adenosine Triphosphatases↗
PubMed2000

Hepatitis C virus NS5A protein protects against TNF-alpha mediated apoptotic cell death.

Hepatitis C virus (HCV) often causes a prolonged and persistent infection which may lead to hepatocellular carcinoma. We have previously reported that the nonstructural 5A (NS5A) protein of HCV promotes cell growth [Ghosh, A.K., Steele, R., Meyer, K., Ray, R., Ray, R.B., 1999. Hepatitis C virus NS5A protein modulates cell cycle regulatory genes and promotes cell growth. J. Gen. Virol. 80, 1179-1183]. In this study, we investigated the role of HCV NS5A (genotype 1a, strain H) in TNF-alpha induced apoptotic cell death. HepG2 cells expressing NS5A exhibited an inhibitory role in relation to TNF-alpha mediated apoptotic cell death. The NS5A protein blocked the activation of caspase-3 and inhibited proteolytic cleavage of the death substrate poly (ADP-ribose) polymerase in TNF-alpha induced cells. Together, these results suggest that HCV NS5A protein protects against TNF-alpha mediated apoptotic cell death.

Blotting, Western↗
PubMed2000

Facilitating day-to-day decision making in palliative care.

As part of a larger grounded theory study investigating the process by which palliative care patients make everyday choices, a secondary analysis of data was conducted to investigate the ways nurses support or restrict patients' participation in their care. Constant comparative methods were used to generate a detailed, contextually grounded description of nurses' strategies that influenced patients' participation in making everyday choices about their personal and nursing care. Data consisted of field notes derived from observations of patients and their caregivers in two hospital-based palliative care units and from 23 transcripts of interviews with participating nurses and patients. Nurses' efforts to support patients' participation in decision making were described as a four-phase process: getting to know the patient, enhancing opportunities for choice, being open to patient choice, and respecting choice. Factors influencing nurses' use of supportive behaviors and behaviors that restricted patients' participation in everyday choices were identified. Given the importance patients attributed to making choices, these findings provide a foundation for the design of nursing interventions that hold great potential for directly influencing quality of life.

Adult↗
PubMed2000

The value of early postictal EEG in children with complex febrile seizures.

PURPOSE: To assess the usefulness of an early postictal EEG in neurologically normal children with complex febrile seizures. METHODS: We conducted a retrospective chart review of all neurologically normal children who were hospitalized over a period of 2.5 years after complex febrile seizures, and had an EEG up to 1 week after the seizure. RESULTS: Thirty-three patients (mean age, 17.8 months) qualified for inclusion into the study. Twenty-four patients were qualified as complex cases based on one factor (prolonged in 9, repetitive in 13, and focal in 2). Nine other patients had two complex factors: in six patients, the seizures were long and repetitive; in two patients, the seizures were focal and repetitive; and in one patient, the seizures were long, focal, and repetitive. Thirteen (39%) patients experienced prior febrile seizures. All 33 patients had a normal postictal sleep EEG. Our results indicate with a 95% probability that the true rate of abnormalities in an early postictal EEG performed on otherwise normal children with complex febrile seizures is 8.6% or less. CONCLUSIONS: The yield of abnormalities of an early postictal EEG in this population is low and similar to the reported rate of abnormalities in children with simple febrile seizures. The routine practice of obtaining an early EEG in neurologically normal children with complex febrile seizures is not justified.

Child, Preschool↗
PubMed1999

PTEN transcriptionally modulates c-myc gene expression in human breast carcinoma cells and is involved in cell growth regulation.

A novel tumor suppressor gene, PTEN, has recently been identified at chromosome 10q23, which is inactivated in a number of different tumor types including breast cancer. An investigation of the functional role suggested that PTEN transcriptionally represses both exogenous and endogenous c-myc expressions in human breast carcinoma cells. PTEN, when ectopically expressed in human breast carcinoma cells, exhibited an inhibition of phosphorylation of both activating residues of protein kinase B (PKB)/AKT at Ser-473 and Thr-308 without any significant alteration of AKT expression. Furthermore, introduction of PTEN into human breast carcinoma cells induced apoptotic cell death and inhibited cell growth and tumor formation in nude mice. Taken together, our data suggest that PTEN acts as a transcriptional repressor, inhibits the AKT-mediated cell survival signaling pathway, and negatively regulates human breast carcinoma cell growth. These results further emphasize the potential of PTEN as a gene therapeutic agent.

Animals↗
PubMed1999

MBP-1 physically associates with histone deacetylase for transcriptional repression.

MBP-1, a c-myc promoter binding protein, is a mammalian transcription factor with intriguing properties including transcriptional repression of cellular genes. Recently, we have identified and characterized two different repressor domains of MBP-1. In this report, we have demonstrated that MBP-1 physically associates with histone deacetylase (HDAC), thus promoting formation of neucleosomes that inhibit transcription. Trichostatin A, an inhibitor of histone deacetylase, significantly reduces MBP-1-mediated transcriptional repression. However, MBP-1-mediated repression on c-myc promoter is resistant to histone deacetylase activity. Our results suggest that MBP-1 represses transcription by recruiting histone deacetylase as one of the mechanisms, whereas the other mechanism is resistant to HDAC activity and probably related to direct binding of promoter sequences or interaction through yet unidentified factor.

3T3 Cells↗
PubMed1999

Ultrasound densitometry of the os calcis in patients with hemiparesis following a cerebrovascular accident.

Ultrasound densitometry has been measured in the os calcis of 31 stroke patients (14 women, 17 men), ages 46-87 years, to determine whether bone density is lower than expected for normal subjects at this site, and to investigate whether or not the stroke side has lower values than the nonstroke side. We have also measured a large control group of 268(39 men, 228 women) subjects who showed similar values to other published data. Immobility is a known precursor to bone loss and so we also compared ultrasound Stiffness Index with an index of mobility in 22 of the stroke patients. In healthy subjects, ultrasound densitometry (measured as Stiffness) fell by 25% in females from 48-52 to 68-72 years. Stiffness (expressed as z-score) in patients with stroke was low in females (P < 0.02) but not in males, but both stroke side and nonstroke side were equally low. Stiffness did not decline with time since stroke, but did correlate with mobility after stroke, on the stroke (r = 0.73) and nonstroke (r = 0.62) side. The data suggest that stroke patients, particularly females, have low bone density before the stroke event. The greater ultrasound Stiffness with increasing mobility after stroke may suggest that active rehabilitation after stroke may produce denser bone.

Activities of Daily Living↗
PubMed1999

Hepatitis C virus NS5A protein modulates cell cycle regulatory genes and promotes cell growth.

The phosphoprotein NS5A of hepatitis C virus has recently been suggested to control PKR protein kinase for resistance to interferon. To investigate other functions of NS5A, studies were initiated on the regulation of transcription of important cellular genes and of cell growth by this protein. The results suggested that NS5A protein represses transcription of the cell cycle regulatory gene p21WAF1, while it activates the human proliferating cell nuclear antigen gene in murine fibroblasts and human hepatoma cells. Furthermore, introduction of NS5A into murine fibroblasts (NIH3T3) promoted anchorage-independent growth and tumour formation in nude mice. Thus, NS5A appears to exhibit a role in cell growth regulation.

Animals↗
PubMed1999

Functional domains of c-myc promoter binding protein 1 involved in transcriptional repression and cell growth regulation.

We initially identified c-myc promoter binding protein 1 (MBP-1), which negatively regulates c-myc promoter activity, from a human cervical carcinoma cell expression library. Subsequent studies on the biological role of MBP-1 demonstrated induction of cell death in fibroblasts and loss of anchorage-independent growth, reduced invasive ability, and tumorigenicity of human breast carcinoma cells. To investigate the potential role of MBP-1 as a transcriptional regulator, a chimeric protein containing MBP-1 fused to the DNA binding domain of the yeast transactivator factor GAL4 was constructed. This fusion protein exhibited repressor activity on the herpes simplex virus thymidine kinase promoter via upstream GAL4 DNA binding sites. Structure-function analysis of mutant MBP-1 in the context of the GAL4 DNA binding domain revealed that MBP-1 transcriptional repressor domains are located in the N terminus (amino acids 1 to 47) and C terminus (amino acids 232 to 338), whereas the activation domain lies in the middle (amino acids 140 to 244). The N-terminal domain exhibited stronger transcriptional repressor activity than the C-terminal region. When the N-terminal repressor domain was transferred to a potent activator, transcription was strongly inhibited. Both of the repressor domains contained hydrophobic regions and had an LXVXL motif in common. Site-directed mutagenesis in the repressor domains indicated that the leucine residues in the LXVXL motif are required for transcriptional repression. Mutation of the leucine residues in the common motif of MBP-1 also abrogated the repressor activity on the c-myc promoter. In addition, the leucine mutant forms of MBP-1 failed to suppress cell growth in fibroblasts like wild-type MBP-1. Taken together, our results indicate that MBP-1 is a complex cellular factor containing multiple transcriptional regulatory domains that play an important role in cell growth regulation.

3T3 Cells↗
PubMed1999

Evaluation of an evidence-based guideline for bronchiolitis.

OBJECTIVE: To describe the effect of implementing an evidence-based clinical practice guideline for the inpatient care of infants with bronchiolitis at the Children's Hospital Medical Center in Cincinnati, Ohio. METHODOLOGY: A multidisciplinary team generated the guideline for infants < or = 1 year old who were admitted to the hospital with a first-time episode of typical bronchiolitis. The guideline was implemented January 15, 1997, and data on all patients admitted with bronchiolitis from that date through March 27, 1997, were compared with data on similar patients admitted in the same periods in the years 1993 through 1996. Data were extracted from hospital charts and clinical and financial databases. They included LOS and use and costs of resources ancillary to bed occupancy. RESULTS: After implementation of the guideline, admissions decreased 29% and mean LOS decreased 17%. Nasopharyngeal washings for respiratory syncytial virus were obtained in 52% fewer patients. Twenty percent fewer chest radiographs were ordered. There were significant reductions in the use of all respiratory therapies, with a 30% decrease in the use of at least 1 beta-agonist inhalation therapy. In addition, 51% fewer repeated inhalations were administered. Mean costs for all resources ancillary to bed occupancy decreased 37%. Mean costs for respiratory care services decreased 77%. CONCLUSIONS: An evidence-based clinical practice guideline for managing bronchiolitis was highly successful in modifying care during its first year of implementation.guideline, bronchiolitis, evidence-based medicine, pediatrics, outcome research.

Administration, Inhalation↗
PubMed1998

Hepatitis C virus core protein represses p21WAF1/Cip1/Sid1 promoter activity.

Hepatitis C virus (HCV) often causes a prolonged and persistent infection, and an association between hepatocellular carcinoma (HCC) and HCV infection has been noted. Recent experimental evidence using a cloned genomic region suggests that the putative core protein of HCV has numerous biological properties and is implicated as a viral factor for HCV mediated pathogenesis. WAF1/Cip1/Sid1 (p21) is the prototype of a family of proteins that inhibit cyclin-dependent kinases (CDK) and regulate cell cycle progression in eukaryotic cells. In this study, we have observed that the HCV core protein represses the transcriptional activity of the p21 promoter when tested separately by an in-vitro transient expression assay using murine fibroblasts (NIH3T3), human hepatocellular carcinoma (HepG2), and human cervical carcinoma (HeLa) cells. A deletion analysis of the p21 promoter suggested that the HCV core responsive region is located downstream of the p53 binding site. A gel mobility shift analysis showed that the HCV core protein does not bind directly to p21 regulatory sequences. Thus, the HCV core protein appears to act as an effector in the promotion of cell growth by repressing p21 transcription through unknown cellular factor(s).

Animals↗
PubMed1998

Inhibition of tumor necrosis factor (TNF-alpha)-mediated apoptosis by hepatitis C virus core protein.

Hepatitis C virus (HCV) putative core protein has displayed many intriguing biological properties. Since tumor necrosis factor (TNF) plays an important role in controlling viral infection, in this study the effect of the core protein was investigated on the TNF-alpha induced apoptosis of human breast carcinoma cells (MCF7). HCV core protein when expressed inhibited TNF-alpha-induced apoptotic cell death unlike the control MCF7 cells, as determined by cell viability and DNA fragmentation analysis. Additionally, HCV core protein blocked the TNF-induced proteolytic cleavage of the death substrate poly(ADP-ribose) polymerase from its native 116-kDa protein to the characteristic 85-kDa polypeptide. Results from this study suggest that the HCV core protein plays a role in the inhibition of TNF-alpha-mediated cell death. Thus, the ability of core protein to inhibit the TNF-mediated apoptotic signaling pathway may provide a selective advantage for HCV replication, allowing for evasion of host antiviral defense mechanisms.

Apoptosis↗
PubMed1998

The Family Health Project: psychosocial adjustment of children whose mothers are HIV infected.

The psychosocial adjustment of 87 inner-city African American children 6-11 years old whose mothers were HIV infected was compared with that of 149 children from a similar sociodemographic background whose mothers did not report being HIV infected. Children were not identified as being HIV infected. Mother reports, child reports, and standardized reading achievement scores were used to assess 4 domains of adjustment: externalizing problems, internalizing problems, cognitive competence, and prosocial competence. The results indicated that, on average, children from both groups had elevated levels of behavior problem scores and low reading achievement scores when compared with national averages. Relative to children whose mothers were not infected, those whose mothers were HIV infected were reported to have more difficulties in all domains of psychosocial adjustment. Potential family processes that may explain the findings are discussed.

Achievement↗