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Biomedical subjects

C B Thompson

Publications and source records attributed to C B Thompson.

At least 307 records · Page 17Linked to original sources
PubMed1982

Size dependent platelet subpopulations: relationship of platelet volume to ultrastructure, enzymatic activity, and function.

A method for the separation of platelets on the basis of their size has been developed using counterflow centrifugation. Platelets were separated, free of plasma proteins and other cells, into seven subpopulations. The smallest-sized platelets, designated as Fraction 1, had a mean platelet volume (MPV) of 3.94 +/- 0.60 micrometer 3 (SD). Each successive fraction had a progressively larger MPV. The MPV for the largest-sized platelets, designated Fraction 7, was 8.19 +/- 0.64 micrometer 3. The MPV for the original platelets prior to fractionation was 6.57 +/- 0.61 micrometer 3. The mean density of Fraction 1 platelets was 1.067 +/- 0.002 g/cm3, while Fraction 7 had a mean density of 1.072 +/- 0.001 g/cm3. Transmission electron microscopy demonstrated that Fraction 1 had 4.3 +/- 0.9 dense bodies per platelet, and Fraction 7 had 12.6 +/- 2.4 dense bodies per platelet. Platelet LDH activity showed that the Fraction 1 platelets had 4.77 +/- 0.92 iu per 10(10) platelets; Fraction 7 platelets had 14.88 +/- 1.23 iu per 10(10) platelets. The LDH activity in the platelets before separation into subpopulations was 9.47 +/- 1.45 iu per 10(10) platelets. Platelet function was measured by ADP-induced aggregation, serotonin uptake, and thrombin-induced release. Progressively more rapid and more complete aggregation was observed as the platelet size increased over the seven fractions. Serotonin uptake was 4.2 times greater in the Fraction 7 platelets than in the Fraction 1 platelets. Quantitative release of serotonin following thrombin stimulation was significantly greater in the larger-sized platelets than in the smaller-sized platelets. The observed differences in platelet aggregation, dense body content, LDH activity, and serotonin uptake and release suggest that large platelets may be functionally more important than smaller platelets.

Adult↗
PubMed1981

Sedimentation behavior of activated human granulocytes. Aggregation and volume effects.

Human peripheral blood granulocytes (PMNs) obtained from normal adults were studied by an analytical gravity sedimentation system. Exposure of PMNs to endotoxin-activated serum (EAS) in a Ficoll density gradient containing Hank's balanced salt solution with calcium and magnesium produced significantly different sedimentation patterns compared to those from granulocytes exposed to normal serum under the same conditions. Experiments were performed to determine whether changes in granulocyte density, volume, shape, or aggregation were responsible for the sedimentation pattern of granulocytes exposed to EAS. The altered gravity sedimentation behavior of endotoxin-activated granulocytes was abolished when calcium and magnesium were not present in the Ficoll density gradient. Granulocyte aggregation was inhibited by the absence of calcium and magnesium in the medium during granulocyte stimulation, whereas the changes in granulocyte shape and volume associated with granulocyte stimulation were not affected. The data indicate that the altered granulocyte sedimentation pattern in the presence of EAS and calcium and magnesium was produced by granulocyte aggregation and not by changes in granulocyte volume or shape.

Adult↗
PubMedDate not supplied

Determining the National Flight Nurses Association's research priorities.

INTRODUCTION: Increased federal attention to nursing research has prompted professional nursing organizations to develop research programs identifying areas of scientific knowledge most needed for professional and clinical practice. The study purpose was to identify the National Flight Nurses Association's (NFNA's) research priorities. METHODS: A two-round Delphi technique was used, with systematic surveys in Round I mailed to 500 NFNA members. Responses from 127 members were coded to form the Round II survey that was completed by members at the NFNA meeting in St. Louis in October 1993. RESULTS: According to frequency scores, issues of highest priority relate to specialty and nonspecialty team, crew configurations, clinical indications for transport, airway management, educational preparation and continuing education. CONCLUSION: Identified priorities support development of research studies and programs that lead to increased knowledge, facilitate collaborative studies and also provide a basis for research funding.

Air Ambulances↗
PubMedDate not supplied

Documentation of decision-making during air transport.

INTRODUCTION: Decision-making is an integral part of quality patient care. The aim of this study was to evaluate decision-making documentation. METHODS: A retrospective descriptive design was used to examine the documentation for a convenience sample of 48 trauma patients transported by rotor-wing aircraft. RESULTS: A total of 1012 decisions were documented in the 48 records. The decisions were grouped into major conceptual problems. An average of 10.2 +/- 4.56 conceptual problems were identified in each record. The top 10 conceptual problems were evaluated. Adequate documentation was found to support all decision-making related to the top 10 problems. CONCLUSION: Although air medical personnel may not directly document statements of rationale for their decision-making, sufficient data were present in the records to support each documented decision.

Air Ambulances↗
PubMedDate not supplied

Flight nurse research activities.

INTRODUCTION: The study purpose was to identify how members of the Air & Surface Transport Nurses Association (ASTNA), formerly called the National Flight Nurses Association, use research in their flight nursing practice. METHODS: A survey was mailed to each ASTNA member requesting demographic data and a description of research activities used in their practice of flight nursing. RESULTS: Thirty percent of the 1643 members (n = 497) completed the survey. Sixty-four percent (320) of respondents were direct patient care providers, and 47% were certified flight registered nurses (CFRN). Thirteen percent (65) reported that research was mandated in their job description. Sixty-three percent (315) used research to guide practice, and 37% (183) incorporated research into policies and procedures. Thirty percent (149) actively conducted some type of research, 15% (76) presented at national conferences, and 11% (53) published in professional journals. CONCLUSION: Components of the ASTNA research standard are being met by most flight nurses. However, only a small percentage of these nurses are designing and conducting studies and formally disseminating their research findings. Flight nurses are involved in research, but their overall participation could be improved.

Aerospace Medicine↗
PubMedDate not supplied

Intubation quality assurance thresholds.

INTRODUCTION: Quality assurance (QA) and continuous quality improvement (CQI) are valued activities within health-care organizations. Quality assurance indicators as guidelines for quality practice usually are established intuitively. The purpose of this study was to determine an appropriate threshold for successful intubation in patients transported by air and to examine factors impacting this success rate. SETTING: Fifteen rotor-wing programs from across the United States participated. METHOD: The study was a prospective descriptive design. A total of 369 flight crew members agreed to participate, and intubations were attempted on 862 patients during the 12-month study. RESULTS: Intubations were attempted on 862 patients and were successful in 788 (91.4%) of the patients. Of the patients not successfully intubated, 14 received supplemental oxygen only, 25 were supported with bag-valve-mask, 26 received a surgical cricothyroidotomy and for nine patients it was unknown what form of airway support was provided. CONCLUSION: Factors impacting successful intubation include cardiac arrest, use of neuromuscular blockade, use of sedatives and facial trauma. Data from the study support a threshold for successful intubation of between 90% and 95%.

Air Ambulances↗
PubMedDate not supplied

Quality assurance and continuous quality improvement within air transport programs.

INTRODUCTION: In June of 1993, the Association of Air Medical Services (AAMS) Quality Management Committee surveyed 240 air medical programs regarding their Quality Assurance and Continuous Quality Improvement activities. METHODS: The survey tool consisted of questions related to Quality Assurance/Continuous Quality Improvement program structure and specific Quality Assurance indicators contained in the AAMS/NFNA Quality Assurance Resource Document. Comparisons were made among fixed-wing, rotor-wing, and combined programs, for use of the Quality Assurance Resource Document, for availability of computers and for hospital-based versus profit or public service programs. RESULTS: Returned surveys totaled 148 for a 62% return rate, with most of the respondents being single hospital based programs. Ninety-three percent of those surveyed have a Quality Assurance program in place to monitor indicators, whereas 63% have also begun to include the Continuous Quality Improvement team process. Only 50% of respondents use computers in their Quality Assurance/Continuous Quality Improvement activities. CONCLUSION: Significant differences among groups were found for several Quality Assurance indicators.

Air Ambulances↗
PubMedDate not supplied

Basics of research (Part 12): Qualitative research.

Although both the assumptions and methods of qualitative and quantitative approaches in nursing research are different, both have the goal of furthering the scientific basis for practice. A variety of qualitative approaches are available, and which approach to use depends on the purpose of the research. In general, qualitative investigations address broad questions related to description, discovery, or theory building, and, as a consequence, the researcher is concerned with the entire context surrounding the phenomenon of interest rather than concentrating on specific variables thought to influence that phenomenon. The type of data collected and the methods of analysis differ, but qualitative research demands the same careful attention to selecting a design appropriate to answer the research question and the same assurance of rigor in conducting the research and interpreting the results as is required in quantitative studies. When these issues are thoroughly addressed, the clinician has a basis for judging both the accuracy and the applicability of qualitative research findings.

Anthropology, Cultural↗
PubMedDate not supplied

Levels of c-myc oncogene mRNA are invariant throughout the cell cycle.

The steady-state messenger RNA levels of several genes increase when cells are stimulated to proliferate. The transcripts from one such gene, the proto-oncogene c-myc, increase approximately 20-fold shortly after cells are stimulated to proliferate and then decline before the onset of DNA synthesis. It has been inferred from these data that expression of c-myc may be specific to the G1 portion of the cell cycle. Alternatively, this transient increase in c-myc mRNA following the stimulation of quiescent cells could be the result of an activational event that renders the cells competent to enter the cell cycle. To distinguish between these possibilities, we performed experiments to determine whether the amount of c-myc mRNA fluctuates during the cell cycle in cells that are under constant stimulation to proliferate. Although c-myc mRNA does undergo a transient increase within 2 h of serum stimulation of quiescent serum-deprived cells, our results show that the level of c-myc mRNA is constant throughout the cell cycle and does not diminish in density-arrested cells maintained in the presence of serum growth factors. In contrast to c-myc, the mRNA levels of two other genes whose expression has been associated with cellular proliferation do show consistent variations within the cell cycle. Both thymidine kinase (TK) and histone 2b (H2b) mRNA levels increase during S phase in continuously growing cells and decrease when cell replication ceases in density-arrested cultures. Therefore, the transient increase in c-myc transcription following the activation of quiescent cells is not due to the type of cell cycle-dependent regulation characteristic of the TK and H2b genes.

Animals↗
PubMedDate not supplied

c-myc oncogene protein synthesis is independent of the cell cycle in human and avian cells.

Several lines of evidence suggest a role for the myc oncogene in cell proliferation. Most recently, mitogenic stimulation of quiescent lymphoid, fibroblast and epithelial cells has been demonstrated to lead to a sharp increase in c-myc RNA levels. To determine how c-myc expression is linked to the cell proliferative cycle, we have used centrifugal elutriation to enrich for populations of avian and human cells at different stages of the cell cycle. Centrifugal elutriation is a counterflow centrifugation method that separates cells on the basis of volume, a parameter correlating well with progression through the cell cycle. Using myc-specific anti-peptide antibodies, we show here that the synthesis, half-life and modification of c-myc proteins are constant throughout the cell cycle of normal and transformed cells.

Animals↗