Search PubMed⌕ Search

Biomedical subjects

C Patterson

Publications and source records attributed to C Patterson.

At least 55 records · Page 3Linked to original sources
PubMed2001

Reactive oxygen species regulate heat-shock protein 70 via the JAK/STAT pathway.

Reactive oxygen species (ROS) such as hydrogen peroxide (H(2)O(2)) activate intracellular signal transduction pathways implicated in the pathogenesis of cardiovascular disease. H(2)O(2) is a mitogen for rat vascular smooth muscle cells (VSMCs), and protein tyrosine phosphorylation is a critical event in VSMC mitogenesis. Therefore, we investigated whether the mitogenic effects of H(2)O(2), such as stimulation of extracellular signal-regulated kinase (ERK)2, are mediated via activation of cytoplasmic Janus tyrosine kinases (JAKs). JAK2 was activated rapidly in VSMCs treated with H(2)O(2), and signal transducers and activators of transcription (STAT) STAT1 and STAT3 were tyrosine-phosphorylated and translocated to the nucleus in a JAK2-dependent manner. Inhibition of JAK2 activity with AG-490 partially inhibited H(2)O(2)-induced ERK2 activity, suggesting that JAK2 is upstream of the Ras/Raf/mitogen-activated protein kinase-ERK/ERK mitogenic pathway. Because heat-shock proteins (HSPs) can protect cells from ROS, we investigated the effect of H(2)O(2) on HSP expression. H(2)O(2) stimulated HSP70 expression in a time-dependent manner, and AG-490 abolished H(2)O(2)-induced HSP70 expression. H(2)O(2) activated the HSP70 promoter via enhanced binding of STATs to cognate binding sites in the promoter. Regulation of chaperones such as HSP70 via activation of the JAK/STAT pathway suggests that in addition to its growth-promoting effects, this pathway may help VSMCs adapt to oxidative stress.

Animals↗
PubMed2001

Cyclic strain increases protease-activated receptor-1 expression in vascular smooth muscle cells.

Cyclic strain regulates many vascular smooth muscle cell (VSMC) functions through changing gene expression. This study investigated the effects of cyclic strain on protease-activated receptor-1 (PAR-1) expression in VSMCs and the possible signaling pathways involved, on the basis of the hypothesis that cyclic strain would enhance PAR-1 expression, reflecting increased thrombin activity. Uniaxial cyclic strain (1 Hz, 20%) of cells cultured on elastic membranes induced a 2-fold increase in both PAR-1 mRNA and protein levels. Functional activity of PAR-1, as assessed by cell proliferation in response to thrombin, was also increased by cyclic strain. In addition, treatment of cells with antioxidants or an NADPH oxidase inhibitor blocked strain-induced PAR-1 expression. Preincubation of cells with protein kinase inhibitors (staurosporine or Ro 31-8220) enhanced strain-increased PAR-1 expression, whereas inhibitors of NO synthase, tyrosine kinase, and mitogen-activated protein kinases had no effect. Cyclic strain in the presence of basic fibroblast growth factor induced PAR-1 mRNA levels beyond the effect of cyclic strain alone, whereas no additive effect was observed between cyclic strain and platelet-derived growth factor-AB. Our findings that cyclic strain upregulates PAR-1 mRNA expression but that shear stress downregulates this gene in VSMCs provide an opportunity to elucidate signaling differences by which VSMCs respond to different mechanical forces.

Aorta↗
PubMed2001

p47phox is required for atherosclerotic lesion progression in ApoE(-/-) mice.

NADPH oxidase is upregulated in smooth muscle cells (SMCs) in response to growth factor stimulation, concomitant with increased reactive oxygen species (ROS) production. We investigated the role of ROS production by NADPH oxidase in SMC responses to growth factors and in atherosclerotic lesion formation in ApoE(-/-) mice. SMCs from wild-type, p47phox(-/-), and gp91phox(-/-) mice differed markedly with respect to growth factor responsiveness and ROS generation. p47phox(-/-) SMCs had diminished superoxide production and a decreased proliferative response to growth factors compared with wild-type cells, whereas the response of gp91phox(-/-) SMCs was indistinguishable from that of wild-type SMCs. The relevance of these in vitro observations was tested by measuring atherosclerotic lesion formation in genetically modified (wild-type, p47phox(-/-), ApoE(-/-), and ApoE(-/-)/p47phox(-/-)) mice. ApoE(-/-)/p47phox(-/-) mice had less total lesion area than ApoE(-/-) mice, regardless of whether mice were fed standard chow or a high-fat diet. Together, these studies provide convincing support for the hypothesis that superoxide generation in general, and NADPH oxidase in particular, have a requisite role in atherosclerotic lesion formation, and they provide a rationale for further studies to dissect the contributions of ROS to vascular lesion formation.

Animals↗
PubMed2001

Health-related quality of life following podiatric surgery.

This 6-month prospective study investigated the outcomes of foot surgery performed by Fellows of the Australian College of Podiatric Surgeons. The study recruited 140 patients who were treated for orthopedic, neurological, or integumentary diseases of the foot. The majority of subjects who underwent podiatric surgery experienced significant postoperative improvements in a range of health-related quality-of-life dimensions as measured by the disease-specific Foot Health Status Questionnaire (FHSQ) and the generic Short Form 36 (SF-36) questionnaire. Subjects reported a reduction in foot pain, increased levels of physical function, improved general foot health perception, and improved footwear-related quality of life. No significant adverse outcomes or unplanned re-admissions to the hospital were reported. This study demonstrates the advantage of assessing health-related quality of life as opposed to patient satisfaction.

Adult↗
PubMed2000

Hydrogen peroxide- and peroxynitrite-induced mitochondrial DNA damage and dysfunction in vascular endothelial and smooth muscle cells.

The mechanisms by which reactive species (RS) participate in the development of atherosclerosis remain incompletely understood. The present study was designed to test the hypothesis that RS produced in the vascular environment cause mitochondrial damage and dysfunction in vitro and, thus, may contribute to the initiating events of atherogenesis. DNA damage was assessed in vascular cells exposed to superoxide, hydrogen peroxide, nitric oxide, and peroxynitrite. In both vascular endothelial and smooth muscle cells, the mitochondrial DNA (mtDNA) was preferentially damaged relative to the transcriptionally inactive nuclear beta-globin gene. Similarly, a dose-dependent decrease in mtDNA-encoded mRNA transcripts was associated with RS treatment. Mitochondrial protein synthesis was also inhibited in a dose-dependent manner by ONOO(-), resulting in decreased cellular ATP levels and mitochondrial redox function. Overall, endothelial cells were more sensitive to RS-mediated damage than were smooth muscle cells. Together, these data link RS-mediated mtDNA damage, altered gene expression, and mitochondrial dysfunction in cell culture and reveal how RS may mediate vascular cell dysfunction in the setting of atherogenesis.

Cells, Cultured↗
PubMed2000

Systematic implementation of an advance directive program in nursing homes: a randomized controlled trial.

CONTEXT: Although advance directives are commonly used in the community, little is known about the effects of their systematic implementation. OBJECTIVES: To examine the effect of systematically implementing an advance directive in nursing homes on patient and family satisfaction with involvement in decision making and on health care costs. DESIGN: Randomized controlled trial conducted June 1, 1994, to August 31, 1998. SETTING AND PARTICIPANTS: A total of 1292 residents in 6 Ontario nursing homes with more than 100 residents each. INTERVENTION: The Let Me Decide advance directive program included educating staff in local hospitals and nursing homes, residents, and families about advance directives and offering competent residents or next-of-kin of mentally incompetent residents an advance directive that provided a range of health care choices for life-threatening illness, cardiac arrest, and nutrition. The 6 nursing homes were pair-matched on key characteristics, and 1 home per pair was randomized to take part in the program. Control nursing homes continued with prior policies concerning advance directives. MAIN OUTCOME MEASURES: Residents' and families' satisfaction with health care and health care services utilization over 18 months, compared between intervention and control nursing homes. RESULTS: Of 527 participating residents in intervention nursing homes, 49% of competent residents and 78% of families of incompetent residents completed advance directives. Satisfaction was not significantly different in intervention and control nursing homes. The mean difference (scale, 1-7) between intervention and control homes was -0.16 (95 % confidence interval [CI], -0.41 to 0.10) for competent residents and 0.07 (95% CI, -0.08 to 0.23) for families of incompetent residents. Intervention nursing homes reported fewer hospitalizations per resident (mean, 0.27 vs 0.48; P = .001) and less resource use (average total cost per patient, Can $3490 vs Can $5239; P = .01) than control nursing homes. Proportion of deaths in intervention (24%) and control (28%) nursing homes were similar (P = .20). CONCLUSION: Our data suggest that systematic implementation of a program to increase use of advance directives reduces health care services utilization without affecting satisfaction or mortality.

Advance Directives↗
PubMed2000

Focal elastic obstruction of the inferior vena cava.

Obstruction of the supra-hepatic inferior vena cava (IVC) is a common cause of hepatic venous hypertension and the most common cause of Budd-Chiari Syndrome. Because most cases of IVC obstruction go undiagnosed until Budd-Chiari Syndrome develops, the natural history of IVC obstruction is not well defined. We report a case of a focal, elastic, non-membranous obstruction of the IVC causing hepatic venous hypertension and elevated serum transaminases in a 36-year-old man. The obstruction was successfully treated with placement of a self-expanding metallic stent with normalization of hepatic transaminases.

Adult↗
PubMed2000

New rules impact sedation and anesthesia care, Part 1.

Learn why the Joint Commission has revised its anesthesia care standards. The new standards incorporate four sedation levels: minimum sedation, moderate sedation/analgesia, deep sedation/analgesia, and anesthesia.

Anesthesia↗
PubMed2000

New rules impact sedation and anesthesia care, Part 2.

In Part 1, the author explained the four new definitions that are changing the Joint Commission's sedation and anesthesia standards: minimum sedation, moderate sedation/analgesia, deep sedation/analgesia, and anesthesia. Part 2 explains how these definitions will impact the delivery of care in your units.

Anesthesia↗
PubMed2000

The human herpesvirus 8 homolog of Epstein-Barr virus SM protein (KS-SM) is a posttranscriptional activator of gene expression.

Homologs of the Epstein-Barr virus (EBV) SM protein exist in several human and nonhuman herpesviruses. Structure and function differ significantly among these proteins. We have cloned and characterized the human herpesvirus 8 (HHV8) gene, KS-SM, which is homologous to the EBV SM and herpes simplex virus ICP27 genes, from an HHV8-infected primary effusion lymphoma. KS-SM is shown to be a posttranscriptional activator of gene expression in cotransfection studies. KS-SM activated gene expression in a gene-specific, promoter-independent manner. In particular, KS-SM enhanced the expression of KDR/flk-1, a receptor for vascular endothelial growth factor (VEGF), in cotransfection studies. Since expression of KDR/flk-1 is increased in Kaposi's sarcoma and HHV8-infected cell cultures and VEGF enhances the proliferation of HHV8-infected cells, KS-SM may play a pathogenic role in Kaposi's sarcoma.

Amino Acid Sequence↗