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Biomedical subjects

K Davis

Publications and source records attributed to K Davis.

At least 91 records · Page 5Linked to original sources
PubMed1999

CASS Registry long term surgical survival. Coronary Artery Surgery Study.

OBJECTIVES: To show the effect of clinical, angio and demographic traits on late survival of Coronary Artery Surgery Study (CASS) patients following coronary artery bypass grafting (CABG) and introduce Hazard Function analysis to CASS survival data. METHODS: Patients were reached by mail survey with 94% response. By National Death Index, vital status was obtained in 99.7% (n = 8221) with a mean follow up of 15 years. Cox proportional hazard and Blackstone Hazard Function regressions were used to assess effects of preoperative traits. RESULTS: Ninety percent of patients were alive at 5, 74% at 10 and 56% at 15 years. Of those age 65 and age 75 at operation, 74% and 59% were living at 10 years and 54% and 33% at 15 years (now age 90), survival exceeding the matched U.S. population. Hazard Function falls rapidly after CABG to 9 to 12 months, then rises, doubling by 15 years. Young patients, below age 35, had lower late survival. The time-segmented Cox model (divided at time suggested by the Hazard Function) identified traits showing predictive power early, throughout and late. Female sex, small body surface, ischemic symptoms and emergency status affected survival early. Heavier weight, infarct(s), diuretics, diabetes, smoking, left main and LAD stenosis and use of vein grafts only increased hazard late only. CONCLUSIONS: There are still lessons from the CASS database. CABG in the elderly is supported by the survival pattern of our patients age 75 at operation. Time-segmented Cox analysis and Hazard Function analysis separate baseline variables into those that predict early mortality and those that predict long survival.

Adult↗
PubMed1999

Discovery of self: exploring, interconnecting and integrating self (concept) and nursing.

Self concept of individual nurses is still largely unexplored in nursing. While the role of self-knowledge and self-actualisation are recognised as integral to nursing practice, little has been done to examine their relationships to self concept and nursing practice. The aim of this research study was to explore the role and significance that self concept plays in women nurses' experience of their beginning practice. The exploration examined factors which contribute to and impact on self concept within a nursing practice environment. Self concept relates to how an individual experiences oneself and is integrally linked to one's interactions and relationships with others. This two phase research was situated in critical and feminist theory using reflective journalling (phase one) and story telling/narrative (phase two) as the research methods. This paper discusses the three major themes which arose in phase one of the research. Those were: exploring experiences; interconnecting personal and professional worlds; and, integrating self 'into' nursing. The paper also explores inter-subjectivity in terms of the contribution this concept makes to our understanding of research findings.

Female↗
PubMed1999

An RGS protein regulates the pheromone response in the fission yeast Schizosaccharomyces pombe.

The rate and extent of a cell's response to an extracellular stimulus is influenced by regulators that act on the intracellular signalling machinery. Although not directly involved in propagating the intracellular signal, regulators control the activity of the proteins that transmit the signals. To understand this aspect of cell signalling, we have studied the pheromone response pathway in the fission yeast Schizosaccharomyces pombe, a relatively simple signalling system in a genetically tractable organism. We demonstrate this approach by investigating the role of Rgs1, a member of the Regulator of G protein Signalling (RGS) family of proteins. The rgs1 gene was identified through the Sz. pombe genome sequencing project (accession number Q09777) and recognized as having similarity to RGS proteins [Tesmer et al. (1997) Cell 89: 251-261], but this is the first report concerning the activity of the protein. Strains lacking rgs1 (Deltargs1) are hypersensitive to pheromone stimulation and unable to conjugate with a mating partner. Inhibition of mating occurs at a relative late stage in the process as Deltargs1 strains exhibit pheromone-dependent transcription and form shmoos. Expression of SST2 (an RGS protein that regulates pheromone signalling in the budding yeast Saccharomyces cerevisiae) overcomes the hypersensitivity of the Deltargs1 strains but fails to rescue their mating defect.

Amino Acid Sequence↗
PubMed1999

A mouse model for evaluation of prophylaxis and therapy of Ebola hemorrhagic fever.

The Zaire subtype of Ebola virus (EBO-Z) is lethal for newborn mice, but adult mice are resistant to the virus, which prevents their use as an animal model of lethal Ebola infection. We serially passed EBO-Z virus in progressively older suckling mice, eventually obtaining a plaque-purified virus that was lethal for mature, immunocompetent BALB/c and C57BL/6 inbred and ICR (CD-1) outbred mice. Pathologic changes in the liver and spleen of infected mice resembled those in EBO-Z-infected primates. Virus titers in these tissues reached 10(9) pfu/g. The LD50 of mouse-adapted EBO-Z virus inoculated into the peritoneal cavity was approximately 1 virion. Mice were resistant to large doses of the same virus inoculated subcutaneously, intradermally, or intramuscularly. Mice injected peripherally with mouse-adapted or intraperitoneally with non-adapted EBO-Z virus resisted subsequent challenge with mouse-adapted virus.

Adaptation, Physiological↗
PubMed1999

Prospective, randomized comparison of epidural versus parenteral opioid analgesia in thoracic trauma.

OBJECTIVE: To evaluate systemic versus epidural opioid administration for analgesia in patients sustaining thoracic trauma. SUMMARY BACKGROUND DATA: The authors have previously shown that epidural analgesia significantly reduces the pain associated with significant chest wall injury. Recent studies report that epidural analgesia is associated with a lower catecholamine and cytokine response in patients undergoing elective thoracotomy compared with patient-controlled analgesia (PCA). This study compares the effect of epidural analgesia and PCA on pain relief, pulmonary function, cathechol release, and immune response in patients sustaining significant thoracic trauma. METHODS: Patients (ages 18 to 60 years) sustaining thoracic injury were prospectively randomized to receive epidural analgesia or PCA during an 18-month period. Levels of serum interleukin (IL)-1beta, IL-2, IL-6, IL-8, and tumor necrosis factor-alpha (TNF-alpha) were measured every 12 hours for 3 days by enzyme-linked immunosorbent assay. Urinary catecholamine levels were measured every 24 hours. Independent observers assessed pulmonary function using standard techniques and analgesia using a verbal rating score. RESULTS: Twenty-four patients of the 34 enrolled completed the study. Age, injury severity score, thoracic abbreviated injury score, and length of hospital stay did not differ between the two groups. There was no significant difference in plasma levels of IL-1beta, IL-2, IL-6, or TNF-alpha or urinary catecholamines between the two groups at any time point. Epidural analgesia was associated with significantly reduced plasma levels of IL-8 at days 2 and 3, verbal rating score of pain on days 1 and 3, and maximal inspiratory force and tidal volume on day 3 versus PCA. CONCLUSIONS: Epidural analgesia significantly reduced pain with chest wall excursion compared with PCA. The route of analgesia did not affect the catecholamine response. However, serum levels of IL-8, a proinflammatory chemoattractant that has been implicated in acute lung injury, were significantly reduced in patients receiving epidural analgesia on days 2 and 3. This may have important clinical implications because lower levels of IL-8 may reduce infectious or inflammatory complications in the trauma patient. Also, tidal volume and maximal inspiratory force were improved with epidural analgesia by day 3. These results demonstrate that epidural analgesia is superior to PCA in providing analgesia, improving pulmonary function, and modifying the immune response in patients with severe chest injury.

Adolescent↗
PubMed1999

Primary care and psychiatry: anticipating an interfaith marriage.

The emergence of a managed-care--driven health delivery system in the United States has had a major impact on both primary care physicians and psychiatrists. Since a significant portion of psychiatric disorders present in primary care settings and a significant number of patients with emotional disorders receive their care from primary care physicians, the convergence of the two fields of medicine seems likely. Surveys document that both the diagnosis and the treatment of emotional disorders are inadequate in primary care. The authors review possible approaches to rectifying this situation and show that the attachment of the psychiatrist to the primary care team offers many advantages to the provision of clinical services, the education of a diverse group of trainees, and the collaboration of two categories of physician not typically seen as working closely together. The authors also describe an outpatient county medical clinic in which the concept of "attachment-liaison" of the psychiatrist to the primary care setting is tested on a daily basis. The authors (a psychiatrist and an internist), who met in this setting, detail their initial expectations and the observed outcomes of having a psychiatrist join the clinic team. The various tasks of the psychiatrist in this primary care setting are enumerated, along with several typical case presentations.

Humans↗
PubMed1999

Familial risk estimation in systemic sclerosis.

BACKGROUND: Familial systemic sclerosis has been rarely reported. Assumptions have therefore been made implying no familial disease aggregation. This study critically challenges the assumption using a methodical population-based epidemiological approach to quantify the prevalence and characteristics of familial systemic sclerosis. METHODS: In this retrospective cohort study the systemic sclerosis prevalence in first degree family members was compared between 715 systemic sclerosis patients (710 families) and 371 randomly ascertained age and gender group-matched general practice controls (371 families). These data, obtained by telephone questionnaire (living patients) or medical records review (deceased patients and untraceable patients of unknown living status), were validated, where necessary, and expressed in terms of relative risk, absolute risk and population point prevalence. RESULTS: Systemic sclerosis affecting first degree members was validated in ten of 710 families. Reporting of systemic disease in another four more distant family members, and the co-occurrence of systemic and localised disease in three families was also documented. Observed and expected disease subtype concordance was 80% (44-97%) and 68% respectively and the female predominance among familial cases was similar to that for non-familial disease. The risk of disease in a subsequent first degree relative was compared to the risk in an initial first degree family member. Its estimated magnitude was wide (11-158). However, use of population prevalence data to determine the expected number of systemic sclerosis patients in the negative cohorts' families suggests the higher estimate is more realistic. Despite the high magnitude, the absolute disease risk in first degree family members remained low--approximating 1%. The population prevalence of familial systemic sclerosis approximated 1.4/million. CONCLUSIONS: This study substantially increases the otherwise small list of documented instances of familial systemic sclerosis. More importantly, it quantifies the risk for the first time, ranking it as the disease's most powerful determinant identified to date.

Cohort Studies↗
PubMed1999

Systemic sclerosis prevalence and mortality in Sydney 1974-88.

BACKGROUND: Systemic sclerosis prevalence and mortality estimates have demonstrated wide variability. The sole Australian study published to date demonstrated high prevalence rates when compared to overseas estimates. The prevalence and mortality findings reported in this paper derive from a larger study which addressed the distribution and determinants of systemic sclerosis within Sydney. AIMS: To determine systemic sclerosis prevalence and mortality rates within Sydney over 15 years, 1974-88. METHODS: Cases were ascertained from multiple sources including death certificates, hospitals, physicians, vascular surgeons' and dermatologists' private practices, a systemic sclerosis self-help group and private medical laboratories. RESULTS: Overall, 715 cases were identified. Females comprised 77% (95% CI: 74-80) of cases. Disease of the limited subtype accounted for 79% (95% CI: 76-82) of all systemic sclerosis, being relatively more frequent in living than deceased cases, and in females than males. Crude prevalence estimates appeared to rise between 1975 (4.52/100,000 95% CI:3.75-5.29/100,000) and 1988 (8.62/100,000 95% CI:7.64-9.60/100,000) as did estimates of diffuse disease. However, diffuse disease prevalence, when expressed as a proportion of total disease prevalence, showed no significant temporal change. Although crude mortality rates also showed apparent temporal increases (0.24/100,000 in 1975 to 0.80/100,000 in 1988) standardised mortality rates showed less convincing trends (0.41/100,000 in 1976 and 0.40/100,000 in 1988). Death certificate-derived mortality rates provided relatively large underestimates of total mortality. However, these underestimates were relatively constant over time. CONCLUSIONS: This study has demonstrated systemic sclerosis prevalence and mortality rates comparable to overseas estimates, consistently higher prevalence and mortality rates in females than males, proportionally higher rates of diffuse disease in males than females and in deceased cases than living cases, a diffuse: limited disease ratio apparently stable over time, apparently increasing temporal prevalence and mortality rates and, by implication, rising incidence rates. The observed temporal rise in diffuse disease prevalence and the absence of a convincing fall in diffuse disease mortality suggests a rising temporal incidence rate of diffuse disease. Standardised mortality rates demonstrated less consistent trends than did crude mortality rates and failed to demonstrate convincing declines in mortality subsequent to the introduction of ACE inhibitors for management of systemic sclerosis renal disease. Death certificate-derived systemic sclerosis mortality rates considerably and consistently underestimated systemic sclerosis-all cause mortality.

Data Collection↗
PubMed1999

Nitrotyrosine formation with endotoxin-induced kidney injury detected by immunohistochemistry.

The presence of nitrotyrosine in the kidney has been associated with several pathological conditions. In the present study, we investigated nitrotyrosine formation in rat kidney after animals received endotoxin for 24 h. With lipopolysaccharide (LPS) treatment, immunohistochemical data demonstrated intense nitrotyrosine staining throughout the kidney. In spite of marked nitrotyrosine formation, the architectural appearance of tubules, glomeruli, and capillaries remained intact when examined by reticulin staining. Our data suggested that the marked staining of nitrotyrosine in proximal tubular epithelial cells was in the subapical compartment where the endocytic lysosomal apparatus is located. Thus a large portion of nitrotyrosine may come from the hydrolysis of nitrated proteins that are reabsorbed by the proximal tubule during the LPS treatment. We also found the colocalization of nitric oxide synthase (NOS-1) and nitrotyrosine within the macula densa of LPS-treated rats by using a double fluorescence staining method. In renal arterial vessels, vascular endothelial cells were more strongly stained for nitrotyrosine than vascular smooth muscle cells. Control animals without LPS treatment showed much less renal staining for nitrotyrosine. The general distribution of nitrotyrosine staining in control rat renal cortex is in the proximal and convoluted tubules, whereas the endothelial cells of vasa recta are major areas of nitrotyrosine staining in inner medulla. The renal distribution of nitrotyrosine in control and LPS-treated animals suggests that protein nitration may participate in renal regulation and injury in ways that are yet to be defined.

Animals↗
PubMed1999

Understanding the diverse needs of the Medicare population: implications for Medicare reform.

Meeting the health care needs of millions of elderly and disabled Americans is central to the debate over Medicare's future. Using data from a nationally representative survey of 3,309 beneficiaries, Medicare's most vulnerable beneficiaries were profiled, examining variations in coverage, satisfaction, access, and financial difficulties. A substantial portion of the Medicare population--two thirds--were found to have health problems or low incomes. The analysis found that about 40% of beneficiaries with incomes below the poverty level, in fair or poor health, or with ADL limitations, have difficulties paying their medical bills or getting needed health care. Medicare's disabled, under-65 beneficiaries are at even higher risk: nearly half (47%) have health care access problems or deal with financial hardship due to medical bills. The diverse needs and experiences of the Medicare population are underscored, providing new insights into the challenge of maintaining or improving protection for those with greatest need while assuring the long-term fiscal viability of the program.

Aged↗
PubMed1999

Contemporary theories and contemporary nursing--advancing nursing care for those who are marginalized.

This paper critiques the topic of postmodernism and how it is represented in nursing and social science literature. This critique classified the debates into three identifiable constructs, those being: dissatisfaction; fragmentation and integration. The authors propose a solution from the integration debate by putting forward the notion of an 'integrated postmodern turn'. The 'solution' is situated within feminism and draws on modernist and postmodernist theory. The integrated model is grounded in nursing clinical examples which demonstrate the usefulness and workability of this approach when caring for those who are marginalized by nurses because of their ethnicity, gender, cultural and/or spiritual beliefs.

Existentialism↗
PubMed1999

Shaping the future of Medicare.

This article suggests that further major changes in Medicare at this time are unwarranted. The enactment of the Balanced Budget Act (BBA) has eliminated the need for quick action to assure solvency of the Part A Trust Fund, which is projected to be in balance for at least ten years. It will take time to implement and assess the effects of the BBA. The uncertainties of future trends in the health sector and Medicare suggest a go-slow approach. Future reforms to finance health care as the baby boom generation retires should be guided by the goals of continuing to assure health and economic security to elderly and disabled beneficiaries, with particular attention to the financial burdens on lower-income beneficiaries and those with serious illnesses or chronic conditions. Employers are cutting back on retiree health coverage, and the appropriate contribution of employers will need to be addressed. The BBA included major provisions to expand Medicare managed care choices. Special attention will need to be given to how well these innovations work, their cost impact on Medicare, the extent to which beneficiaries are able to make informed choices, and whether risk selection among plans and between traditional Medicare and plans can be adequately addressed. Most of the savings of BBA came from tighter payment rates to managed care plans and fee-for-service providers; it is unclear whether these will lead to rates well below the private sector or whether further savings can be achieved by extending these changes beyond 2002.

Budgets↗
PubMed1999

Zone I retroperitoneal hematoma identified by computed tomography scan as an indicator of significant abdominal injury.

OBJECTIVE: All zone I retroperitoneal hematomas (Z1RPHs) identified at laparotomy for blunt trauma traditionally require exploration. The purpose of this study was to correlate patient outcome after blunt abdominal trauma with the presence of Z1RPH diagnosed on admission computed tomography (CT) scan. METHODS: This is a retrospective review of patients with blunt trauma who were admitted to a Level 1 trauma center and who underwent CT scan during a 40-month period. All scans with a traumatic injury were reviewed to identify and grade Z1RPH as mild, moderate, or severe. Patients requiring operative treatment were compared with those who were observed. Statistical analysis was performed with Student's t test and chi-square test, with P < .05 considered significant. RESULTS: Eighty-five (15.5%) of the CT scans were positive for Z1RPH. None of the 50 patients with a mild Z1RPH had their treatment altered. Of the 29 patients with a moderate or severe Z1RPH, 8 required celiotomy. The patients requiring celiotomy had significant elevations of solid viscus score (SVS) (4.9 +/- 1.6 versus 1.8 +/- 0.3), abdominal Abbreviated Injury Scale (3.8 +/- 0.3 versus 2.6 +/- 0.3), and transfusion requirements (13 +/- 4 versus 2 +/- 1). All patients (N = 4) with an SVS >4 required operative treatment. Seventy-two percent of patients with more than 1 intra-abdominal injury required abdominal exploration. CONCLUSIONS: The presence of a moderate or severe Z1RPH and more than 1 intra-abdominal injury or an SVS >4 on admission CT scan is an important radiographic finding. This injury pattern should be considered a contraindication for nonoperative treatment of the associated solid organ injury.

Abdominal Injuries↗