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Biomedical subjects

K Davis

Publications and source records attributed to K Davis.

At least 73 records · Page 4Linked to original sources
PubMed2000

Attribution of injury to alcohol involvement in young adults seriously injured in alcohol-related motor vehicle crashes.

BACKGROUND: Approximately 40% of all traffic fatalities are associated with the use of alcohol. Hospitalization for serious injury after a motor vehicle crash related to use of alcohol may be an opportunity to change drinking behaviors in non-alcohol-dependent drinkers, thereby reducing the risk for future disability and death. OBJECTIVES: To determine the degree to which non-alcohol-dependent adults aged 18 to 45 years with alcohol-related vehicular trauma attributed their injury to use of alcohol. METHODS: During hospitalization, 132 subjects involved in alcohol-related motor vehicle crashes were interviewed. The interviews included the question, "To what extent do you believe your alcohol consumption was responsible for this injury?" Responses were measured on a 7-point scale ranging from 1 (not at all) to 7 (totally). RESULTS: In response to the question about attribution of injury to alcohol, 37.8% of subjects responded "not at all," 24.3 responded "somewhat," and 37.9% responded "mostly" or "totally." Spearman rank correlation between attribution of injury to alcohol involvement and blood alcohol content at admission was r = 0.440 (P < .001). CONCLUSIONS: More than 60% of patients injured in alcohol-related motor vehicle crashes attributed their injury partly or totally to use of alcohol. When alcohol-free, hospitalized patients with higher blood levels of alcohol on admission were more likely than those with lower levels to attribute their injury to alcohol. Hospitalization for a motor vehicle crash related to use of alcohol provides an opportunity for interventions to decrease drinking.

Accidents, Traffic↗
PubMed2000

The effects of passive humidifier dead space on respiratory variables in paralyzed and spontaneously breathing patients.

BACKGROUND: Passive humidifiers have gained acceptance in the intensive care unit because of their low cost, simple operation, and elimination of condensate from the breathing circuit. However, the additional dead space of these devices may adversely affect respiratory function in certain patients. This study evaluates the effects of passive humidifier dead space on respiratory function. METHODS: Two groups of patients were studied. The first group consisted of patients recovering from acute lung injury and breathing spontaneously on pressure support ventilation. The second group consisted of patients who were receiving controlled mechanical ventilation and were chemically paralyzed following operative procedures. All patients used 3 humidification devices in random order for one hour each. The devices were a heated humidifier (HH), a hygroscopic heat and moisture exchanger (HHME) with a dead space of 28 mL, and a heat and moisture exchanger (HME) with a dead space of 90 mL. During each measurement period the following were recorded: tidal volume, minute volume, respiratory frequency, oxygen consumption, carbon dioxide production, ratio of dead space volume to tidal volume (VD/VT), and blood gases. In the second group, intrinsic positive end-expiratory pressure was also measured. RESULTS: Addition of either of the passive humidifiers was associated with increased VD/VT. In spontaneously breathing patients, VD/VT increased from 59 +/- 13 (HH) to 62 +/- 13 (HHME) to 68 +/- 11% (HME) (p < 0.05). In these patients, constant alveolar ventilation was maintained as a result of increased respiratory frequency, from 22.1 +/- 6.6 breaths/min (HH) to 24.5 +/- 6.9 breaths/min (HHME) to 27.7 +/- 7.4 breaths/min (HME) (p < 0.05), and increased minute volume, from 9.1 +/- 3.5 L/min (HH) to 9.9 +/- 3.6 L/min (HHME) to 11.7 +/- 4.2 L/min (HME) (p < 0.05). There were no changes in blood gases or carbon dioxide production. In the paralyzed patient group, VD/VT increased from 54 +/- 12% (HH) to 56 +/- 10% (HHME) to 59 +/- 11% (HME) (p < 0.05) and arterial partial pressure of carbon dioxide (PaCO2) increased from 43.2 +/- 8.5 mm Hg (HH) to 43.9 +/- 8.7 mm Hg (HHME) to 46.8 +/- 11 mm Hg (HME) (p < 0.05). There were no changes in respiratory frequency, tidal volume, minute volume, carbon dioxide production, or intrinsic positive end-expiratory pressure. DISCUSSION: These findings suggest that use of passive humidifiers with increased dead space is associated with increased VD/VT. In spontaneously breathing patients this is associated with an increase in respiratory rate and minute volume to maintain constant alveolar ventilation. In paralyzed patients this is associated with a small but statistically significant increase in PaCO2. CONCLUSION: Clinicians should be aware that each type of passive humidifier has inherent dead space characteristics. Passive humidifiers with high dead space may negatively impact the respiratory function of spontaneously breathing patients or carbon dioxide retention in paralyzed patients. When choosing a passive humidifier, the device with the smallest dead space, but which meets the desired moisture output requirements, should be selected.

Analysis of Variance↗
PubMed2000

The intersection of socioeconomic variables, oral health, and systemic disease: all health care is cultural.

In the last decade, there has been an increase in the proportion of the American population that lacks health insurance. Additionally, long-term disparities in health access and status for populations of color have continued to exist without major change. A review of the literature in periodontia shows a statistical relationship between the risk of periodontal disease and a range of sociodemographic characteristics (race, income, social class). However, the factors giving rise to this increased risk or how to reduce it are unclear. Cultural competence, an elaboration of biopsychosocial theory, hypothesizes a relationship between the culture of a group and its risk of disease and the kind and quality of services obtained. Four areas of a culturally competent approach are cited as a minimum base of standards for providing services to people of color.

Chronic Disease↗
PubMed1999

The 100 most-cited articles from JMB.

Over the last 40 years, JMB has published many thousands of articles, all of which have been important in some way. Compiling a list of the 'most important' however, is an invidious task. Friendships can falter on such an undertaking, but the Institute of Scientific Information has provided us with an objective methodology for 'ranking' articles, according to the number of times any paper is cited in other publications. This evaluation can of course be criticised for its bias towards papers describing novel techniques or methods. Often, the true intellectual milestones may be found in the reference list of the most cited papers. With increasing age, each paper also has more time in which to have been cited, and so the group of highest scoring articles is also dominated by some of the oldest. On the other hand, with increasing time, papers have an increasing chance of being forgotten, and the citation rates of these are therefore also a measure of their persisting importance. On balance, it does represent a value in some way related to how often that paper has been used. With many caveats, we present the list of the 100 most cited papers in JMB over the past 40 years. Many of these papers have helped or influenced both a great many people, and a great many subsequent advances in molecular biology.

Bibliometrics↗
PubMed1999

Gene disruption in Schizosaccharomyces pombe using a temperature-sensitive Ura4p.

We have generated a temperature-sensitive form of the Ura4p protein from the fission yeast Schizosaccharomyces pombe. A single T-to-C mutation at nucleotide 782 (relative to the initiator ATG codon of ura4) changes the leucine residue at position 261 in Ura4p to a proline. The mutant Ura4p(ts) supports growth at 30 degrees C but is unable to allow growth at 37 degrees C in the absence of uracil when a single copy of the gene is integrated into the host chromosome. Using the ura4(ts) cassette for gene replacements simplifies the identification of transformants in which the disruption construct has undergone homologous integration into the host chromosome, as these individuals contain a single copy of the ura4(ts) gene and fail to grow when replicated to 37 degrees C in the absence of uracil.

Amino Acid Substitution↗
PubMed1999

Functional characterization of the S. cerevisiae genome by gene deletion and parallel analysis.

The functions of many open reading frames (ORFs) identified in genome-sequencing projects are unknown. New, whole-genome approaches are required to systematically determine their function. A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in rich medium. The phenotypes of more than 500 deletion strains were assayed in parallel. Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium.

Culture Media↗
PubMed1999

Changes in respiratory mechanics after tracheostomy.

OBJECTIVE: To determine the effects of tracheostomy on respiratory mechanics and work of breathing (WOB). DESIGN: A before-and-after trial of 20 patients undergoing tracheostomy for repeated extubation failure. SETTING: Surgical intensive care unit at a university teaching hospital and a level I trauma center. PATIENTS: A consecutive sample of 20 patients who met extubation criteria (Pa(O2), >55 mm Hg; pH >7.30; and respiratory rate, <30/min on room air continuous positive airway pressure after 20 minutes) but failed extubation on 2 occasions were eligible for the study. INTERVENTIONS: Respiratory mechanics, lung volumes, and WOB were measured before and after tracheostomy. MAIN OUTCOME MEASURES: Patients in whom extubation fails often progress to unassisted ventilation after tracheostomy. The study hypothesis was that tracheostomy would result in improved pulmonary function through changes in respiratory mechanics. RESULTS: Data are given as means +/- SDs. After tracheostomy, WOB per liter of ventilation (0.97+/-0.32 vs. 0.81+/-0.46 J/L; P<.09), WOB per minute (8.9+/-2.9 vs. 6.6+/-1.4 J/min; P<.04), and airway resistance (9.4+/-4.1 vs. 6.3+/-4.5 cm H20/L per second; P<.07) were reduced compared with breathing via an endotracheal tube. These findings, however, do not fully explain the ability of patients to be liberated from mechanical ventilation after tracheostomy. In 4 patients who were extubated before tracheostomy, WOB was significantly greater during extubation than when breathing through an endotracheal or tracheostomy tube (1.2+/-0.19 vs. 0.81+/-0.24 vs. 0.77+/-0.22 J/L). CONCLUSIONS: We believe that the rigid nature of the tracheostomy tube represents reduced imposed WOB compared with the longer, thermoliable endotracheal tube. The clinical significance of this effect is small, although as respiratory rate increases, the effects are magnified. In patients in whom extubation failed, WOB may be elevated because of incomplete control of the upper airway. Future studies should evaluate the cause of increased WOB after extubation.

Adult↗
PubMed1999

A prospective comparison of laparoscopic ultrasound vs intraoperative cholangiogram during laparoscopic cholecystectomy.

BACKGROUND: The laparoscopic ultrasound (US) probe provides a new modality for evaluating biliary anatomy during laparoscopic cholecystectomy (LC). METHODS: We performed a laparoscopic US examination in 65 patients without suspected common bile duct (CBD) stones prior to the performance of a laparoscopic cholangiogram (IOC). We then compared the cost, time required, surgeon's assessment of difficulty, and interpretations of findings. RESULTS: There was a significant difference in the cost of US versus the cost of IOC ($362 +/- 12 versus $665 +/- 12; p < 0.05). Surgeons who had performed >10 US (EXP) were compared with those who had performed </=10 (NOV). There were significant differences between the EXP and NOV groups in ease of examination, visualization of biliary anatomy, and accuracy of measurement of the CBD. CONCLUSIONS: The use of laparoscopic US for the accurate evaluation of the CBD and biliary anatomy requires that the surgeon has surpassed the learning curve, which we have defined as having performed >10 US exams.

Adult↗
PubMed1999

Primitive human hematopoietic progenitor cells express receptors for granulocyte-macrophage colony-stimulating factor.

Most cytokines act only synergistically in assays of primitive progenitor cell proliferation, and effects have usually been observed first after prolonged cell culture. Studies reporting that primitive progenitors lack receptors for a number of cytokines, including granulocyte-macrophage colony stimulating factor (GM-CSF), could indicate that several "synergistic" cytokines primarily affect cells that have differentiated in vitro. Here, however, we show that freshly isolated primitive progenitor cells (CD34hi CD38-) express receptors for GM-CSF at levels 20%-30% of granulo-monocytic progenitors. Although GM-CSF had minimal effects on the survival or proliferation of primitive progenitors when added alone, the cytokine enhanced stem cell factor (SCF) induced cell cycle entry in the first generation. The effect was not observed when cells were incubated sequentially with SCF and GM-CSF. The results suggest that the synergistic effects of GM-CSF are mediated directly on primitive progenitor cells and that the cytokine may be useful to enhance cell cycle entry of hematopoietic stem cells.

Antigens, CD↗
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↗