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Biomedical subjects

K Davis

Publications and source records attributed to K Davis.

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

Multiinstitutional experience with the management of superior mesenteric artery injuries.

BACKGROUND: Superior mesenteric artery (SMA) injuries are rare and often lethal injuries incurring very high morbidity and mortality. The purposes of this study are to review a multiinstitutional experience with these injuries; to analyze Fullen's classification based on anatomic zone and ischemia grade for its predictive value; to correlate the American Association for the Surgery of Trauma-Organ Injury Scale (AAST-OIS) for abdominal vascular injury with mortality; and to identify independent risk factors predictive of mortality, describing current trends for the management of this injury in America. DESIGN: We performed a retrospective multiinstitutional study of patients sustaining SMA injuries involving 34 trauma centers in the US over 10 years. Outcomes variables, both continuous and dichotomous, were analyzed initially with univariate methods. For the subsequent multivariate analysis, stepwise logistic regression was used to identify a set of risk factors significantly associated with mortality. RESULTS: There were 250 patients enrolled, with a mean Revised Trauma Score (RTS) of 6.44 and a mean Injury Severity Score (ISS) of 25. Surgical management consisted of ligation in 175 of 244 patients (72%), primary [corrected] repair in 53 of 244 patients (22%), autogenous grafts were used in 10 of 244 (4%), and prosthetic grafts of PTFE in 6 of 244 patients (2%). Overall mortality was 97 of 250 patients (39%). Mortality versus Fullen's zones: zone I, 39 of 51 (76.5%); zone II, 15 of 34 (44.1%); zone III, 11 of 40 (27.5%); and zone IV, 25 of 108 (23.1%). Mortality versus Fullen's ischemia grade: grade 1, 22 of 34 (64.7%). Mortality versus AAST-OIS for abdominal vascular injury: grade I, 9 of 55 (16.4%); grade II, 13 of 51 (25.5%); grade III, 8 of 20 (40%); grade IV, 37 of 69 (53.6%); and grade V, 17 of 19 (89.5%). Logistic regression analysis identified as independent risk factors for mortality the following: transfusion of greater than 10 units of packed RBCs, intraoperative acidosis, dysrhythmias, injury to Fullen's zone I or II, and multisystem organ failure. CONCLUSION: SMA injuries are highly lethal. Fullen's anatomic zones, ischemia grade, and AAST-OIS abdominal vascular injuries correlate well with mortality. Injuries to Fullen's zones I and II, Fullen's maximal ischemia grade, and AAST-OIS injury grades IV and V, high-intraoperative transfusion requirements, and presence of acidosis and disrhythmias are significant predictors of mortality. All of these predictive factors for mortality must be taken into account in the surgical management of these injuries.

Adolescent↗
PubMed2001

Dual control modes: combining volume and pressure breaths.

New modes of ventilator operation are often introduced without rhyme or reason. The dual control modes are, however, a response of the manufacturers to clinician desire to provide constant minute volume/tidal volume while operating in the pressure support or pressure control mode. Dual control modes allow the ventilator to control pressure or volume. The ventilator cannot control pressure and volume at the same time, so it is an either/or phenomenon. Dual control modes can operate "within a breath" or on a "breath to breath" basis. Dual control within a breath refers to a technique whereby the ventilator switches from pressure to volume control in the middle of a breath. In the technique of dual control breath to breath, all breaths are pressure control breaths, but the level of pressure varies from breath to breath in an effort to maintain a constant tidal volume.

Algorithms↗
PubMed2001

Narrative accounts of tracking the rural domestic violence survivors' journey: a feminist approach.

This research represents the first stage of a project to determine the level of use and effectiveness of informal support networks utilised by Australian rural women. We used a feminist narrative approach with semistructured interviews and a convenience sample of 26 rural women. Only 9 out of 12 women's stories are presented. We found that poverty and geographical, social, and emotional isolation resulted in the privatisation of abuse. Women were triggered to leave the family home when their children, friends, or family became victims of the abuse. They planned their escape by telephone with support of friends and family. Although they used these informal supports, the participants paradoxically expected a high level of expertise in domestic violence knowledge and skills. We recommend an integrated multilevel model of support for rural women in violent intimate relationships and their informal supporters.

Adaptation, Psychological↗
PubMed2001

Universal coverage in the United States: lessons from experience of the 20th century.

Both the rising numbers of uninsured Americans and the recent presidential election have put the issue of universal health insurance coverage back on the national agenda. Lack of health insurance is a major barrier to care for 44 million Americans, and lack of high-quality, comprehensive insurance is a barrier to millions more. Universal coverage is one of the best ways to ensure that all Americans have equitable access to quality care, and it also contributes to the financial stability of health care providers, especially those in the urban safety net. A wide variety of ideas to expand health care coverage were proposed, and in some cases enacted, during the last century. At the beginning of the 21st century, the American health care system is made up of varied elements, ranging from employer-sponsored health insurance for the majority of working-age adults to the public Medicare program for the elderly. While this patchwork system leaves many Americans without health insurance, it also creates many different ways to expand coverage, including various options in both the private and public sectors. By understanding how the current health care system developed, how the various proposals for universal health coverage gained and lost political and public support, and the pros and cons of the various alternatives available to expand coverage, we create a solid base from which to solve the problem of the uninsured in the 21st century.

Health Benefit Plans, Employee↗
PubMed2001

Successful treatment of rhino-orbital mucormycosis without exenteration: the use of multiple treatment modalities.

PURPOSE: To describe the successful management of rhino-orbital mucormycosis without the use of orbital exenteration. METHOD: Case report. RESULTS: The patient had successful eradication of the fungal infection with retention of normal vision and ocular function. CONCLUSIONS: The use of multiple treatment modalities including aggressive surgical debridement guided by intraoperative frozen section monitoring, intravenous liposomal amphotericin B, intraorbital regular amphotericin B and hyperbaric oxygen may allow complete resolution of orbital phycomycosis and spare the patient from the blindness and disfigurement associated with exenteration.

Adult↗
PubMed2001

Prone positioning and inhaled nitric oxide: synergistic therapies for acute respiratory distress syndrome.

BACKGROUND: Inhaled nitric oxide (INO) and prone positioning have both been advocated as methods to improve oxygenation in patients with acute respiratory distress syndrome (ARDS). This study was designed to evaluate the relative contributions of INO and prone positioning alone and in combination on gas exchange in trauma patients with ARDS. METHODS: Sixteen patients meeting the consensus definition of ARDS were studied. Patients received mechanical ventilation in the supine position, mechanical ventilation plus INO at 1 part per million in the supine position, mechanical ventilation in the PP, and mechanical ventilation in the prone positioning plus INO at 1 part per million. A stabilization period of 1 hour was allowed at each condition. After stabilization,hemodynamic and gas exchange variables were measured. RESULTS: INO and prone positioning both increased PaO2/FIO2 compared with ventilation in the supine position. PaO2/FIO2 increased by 14% during use of INO, and 10 of 16 patients (62%) responded to INO in the supine position. PaO2/FIO2 increased by 33%, and 14 of 16 patients (87.5%) responded to the prone position. The combination of INO and prone positioning resulted in an improvement in PaO2/FIO2 in 15 of 16 patients(94%), with a mean increase in PaO2/FIO2 of 59%. Pulmonary vascular resistance was reduced during use of INO, with a greater reduction in pulmonary vascular resistance seen with INO plus prone positioning (175 +/- 36 dynes x s/cm5 vs. 134 +/- 28 dynes x s/cm5) compared with INO in the supine position (164 +/- 48 dynes x s/cm5 vs.138 +/- 44 dynes x s/cm5). There were no significant hemodynamic effects of INO or prone positioning and no complications were seen during this relative short duration of study. CONCLUSIONS: INO and prone positioning can contribute to improved oxygenation in patients with ARDS. The two therapies in combination are synergistic and may be important adjuncts to mechanical ventilation in the ARDS patient with refractory hypoxemia.

Administration, Inhalation↗
PubMed2001

Quantity and rigor of qualitative research in four pastoral counseling journals.

Examines the quantity (N = 26) and rigor of qualitative research in The Journal of Pastoral Care, Pastoral Sciences, Journal of Religion and Health, and Pastoral Psychology for 1993-1997. Defines qualitative research using the work of Douglas Sprenkle and Sidney Moon. Uses the eleven criteria developed by Nicholas Mays and Catherine Pope in British Medical Journal for judging rigor. Finds low quantity and mixed quality and discusses implications.

Bibliometrics↗
PubMed2001

Gaps in health coverage among working-age Americans and the consequences.

This paper examines health coverage and access to care among working-age adults using the Kaiser/Commonwealth 1997 National Survey of Health Insurance. One in three (52 million) working-age adults were either uninsured at the time of the survey or had a recent gap in their health coverage in the past two years. Having even a temporary gap in health coverage made a significant difference in access to care. Compared to the elderly, who are continuously covered by Medicare, working-age adults have greater problems paying their medical bills and gaining access to care and are less satisfied with their health insurance coverage.

Adolescent↗
PubMed2001

Epistemology at work: the ontological relationship between feminist methods, intersubjectivity and nursing research--a research exemplar.

This article explores the importance of strong epistemological and ontological links in nursing research by examining the design and process of a recent research project. The research topic concerns the relationship between self-concept and nursing practice. In this article, the authors demonstrate that commitment to a methodologically consistent process and the necessary associated epistemological and ontological positions provides a depth and structure to nursing research. It is the authors' belief that such consistency within research acts to strengthen the research process, and consequently strengthens nursing's research base and knowledge.

Feminism↗
PubMed2000

Binding of beta-carbolines and related agents at serotonin (5-HT(2) and 5-HT(1A)), dopamine (D(2)) and benzodiazepine receptors.

A large series of beta-carbolines was examined for their ability to bind at [3H]agonist-labeled 5-HT(2A) serotonin receptors. Selected beta-carbolines were also examined at 5-HT(2C) serotonin receptors, 5-HT(1A) serotonin receptors, dopamine D(2) receptors, and benzodiazepine receptors. Indolealkylamines and phenylisopropylamines were also evaluated in some of these binding assays. The beta-carbolines were found to bind with modest affinity at 5-HT(2A) receptors, and affinity was highly dependent upon the presence of ring substituents and ring saturation. The beta-carbolines displayed little to no affinity for 5-HT(1A) serotonin receptors, dopamine D(2) receptors and, with the exception of beta-CCM, for benzodiazepine receptors. Examples of beta-carbolines, indolealkylamines (i.e. N,N-dimethyltryptamine analogs), and phenylisopropylamines have been previously shown to produce common stimulus effects in animals trained to discriminate the phenylisopropylamine hallucinogen DOM (i.e. 1-(2, 5-dimethoxy-4-methylphenyl)-2-aminopropane) from vehicle. Although the only common receptor population that might account for this action is 5-HT(2A), on the basis of a lack of enhanced affinity for agonist-labeled 5-HT(2A) receptors, as well as on their lack of agonist action in the PI hydrolysis assay, it is difficult to conclude that the beta-carbolines behave in a manner consistent with that of other classical hallucinogens.

Animals↗
PubMed2000

Measurement of the W-->taunu production cross section in pp collisions at square root s=1.8 TeV.

We report on a measurement of sigma(pp-->W+X)B(W-->taunu) in pp collisions at sqrt[s]=1.8 TeV at the Fermilab Tevatron. The measurement is based on an integrated luminosity (lum) of 18 pb-1 of data collected with the D0 detector during 1994-1995. We find that sigma(pp-->W+X)B(W-->taunu)=2.22+/-0.09 (stat)+/-0. 10 (syst)+/-0.10 (lum) nb. Lepton universality predicts that the ratio of the tau and electron electroweak charged current couplings to the W boson, gWtau/gWe, be unity. We find gWtau/gWe=0.980+/-0.031, in agreement with lepton universality.

Journal Article↗
PubMed2000

Probing Balitsky-Fadin-Kuraev-Lipatov dynamics in the dijet cross section at large rapidity intervals in pp collisions at sqrt[s]=1800 and 630 GeV.

Inclusive dijet production at large pseudorapidity intervals (Deltaeta) between the two jets has been suggested as a regime for observing Balitsky-Fadin-Kuraev-Lipatov (BFKL) dynamics. We have measured the dijet cross section for large Deltaeta in pp collisions at sqrt[s]=1800 and 630 GeV using the D0 detector. The partonic cross section increases strongly with the size of Deltaeta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alphaBFKL(20 GeV)=1.65+/-0.07.

Journal Article↗
PubMed2000

Flow cytometric analysis of immunoprecipitates: high-throughput analysis of protein phosphorylation and protein-protein interactions.

BACKGROUND: Activation-induced protein phosphorylation can be studied by Western blotting, but this method is time consuming and depends on the use of radioactive probes for quantitation. We present a novel assay for the assessment of protein phosphorylation based on latex particles and flow cytometry. METHODS: This method employs monoclonal antibodies coupled to latex particles to immobilize protein kinase substrates. Their phosphorylation status is assessed by reactivity with phosphoepitope-specific antibodies. The amount of immobilized protein on the particles was analyzed by direct or indirect immunofluorescence with antibodies to nonphosphorylated epitopes. RESULTS: The assay allowed measurement of phosphorylation of multiple protein kinase substrates in stimulated T cells, including the zeta chain of the T-cell receptor, ZAP-70, CD3, CD5, SHP-1, and ERK-2, using 1-3 microg of total cell protein per sample. The assay provided high resolution of kinetics of phosphorylation and dephosphorylation. Interactions of protein kinase substrates with associated signaling molecules were demonstrated. CONCLUSIONS: The novel assay allows high-throughput quantitative measurement of protein modifications during signal transduction.

Animals↗
PubMed2000

Nicotinic receptor subtypes in human brain ageing, Alzheimer and Lewy body diseases.

Human brain ageing is associated with reductions in a variety of nicotinic receptors subtypes, whereas changes in age-related disorders including Alzheimer's disease or Parkinson's disease are more selective. In Alzheimer's disease, in the cortex there is a selective loss of the alpha4 (but not alpha3 or 7) subunit immunoreactivity and of nicotine or epibatidine binding but not alpha-bungarotoxin binding. Epibatidine binding is inversely correlated with clinical dementia ratings and with the level of Abeta1-42, but not related to plaque or tangle densities. In contrast, alpha-bungarotoxin binding is positively correlated with plaque densities in the entorhinal cortex. In human temporal cortex loss of acetylcholinesterase catalytic activity is positively correlated with decreased epibatidine binding and in a transgenic mouse model over expressing acetylcholinesterase, epibatidine binding is elevated. In Parkinson's disease, loss of striatal nicotine binding appears to occur early but is not associated with a loss of alpha4 subunit immunoreactivity. Tobacco use in normal elderly individuals is associated with increased alpha4 immunoreactivity in the cortex and lower densities of amyloid-beta plaques, and with greater numbers of dopaminergic neurons in the substantia nigra pars compacta. These findings indicate an early involvement of the alpha4 subunit in beta-amyloidosis but not in nigro-striatal dopaminergic degeneration.

Acetylcholinesterase↗
PubMed2000

The acute effects of body position strategies and respiratory therapy in paralyzed patients with acute lung injury.

BACKGROUND: Routine turning of critically ill patients is a standard of care. In recent years, specialized beds that provide automated turning have been introduced. These beds have been reported to improve lung function, reduce hospital-acquired pneumonia, and facilitate secretion removal. This trial was designed to measure the physiological effects of routine turning and respiratory therapy in comparison with continuous lateral rotation (CLR). METHODS: The study was a prospective, quasi-experimental, random assignment, trial with patients serving as their own controls. Paralyzed, sedated patients with acute respiratory distress syndrome were eligible for study. Patients were randomized to receive four turning and secretion management regimens in random sequence for 6 h each over a period of 24 h: (1) routine turning every 2 h from the left to right lateral position; (2) routine turning every 2 h from the left to right lateral position including a 15-min period of manual percussion and postural drainage (P&PD); (3) CLR with a specialized bed that turned patients from left to right lateral position, pausing at each position for 2 min; and (4) CLR with a specialized bed that turned patients from left to right lateral position pausing at each position for 2 min, and a 15-min period of percussion provided by the pneumatic cushions of the bed every 2 h. RESULTS: Nineteen patients were entered into the study. There were no statistically significant differences in the measured cardiorespiratory variables. There was a tendency for the ratio of partial pressure of arterial oxygen to fractional inspired oxygen concentration (PaO2/FIO2) to increase (174 +/- 31 versus 188 +/- 36; P = 0.068) and for the ratio of deadspace to tidal volume (Vd/Vt) to decrease (0.62 +/- 0.18 versus 0.59 +/- 0.18; P = 0.19) during periods of CLR, but these differences did not achieve statistical significance. There were statistically significant increases in sputum volume during the periods of CLR. The addition of P&PD did not increase sputum volume for the group as a whole. However, in the four patients producing more than 40 ml of sputum per day, P&PD increased sputum volume significantly. The number of patient turns increased from one every 2 h to one every 10 min during CLR. CONCLUSION: The acute effects of CLR are undoubtedly different in other patient populations (spinal cord injury and unilateral lung injury). The link between acute physiological changes and improved outcomes associated with CLR remain to be determined.

Adult↗