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Biomedical subjects

C M Burns

Publications and source records attributed to C M Burns.

At least 19 recordsLinked to original sources
PubMed1992

The CD45 tyrosine phosphatase regulates phosphotyrosine homeostasis and its loss reveals a novel pattern of late T cell receptor-induced Ca2+ oscillations.

CD45 is a transmembrane tyrosine phosphatase implicated in T cell antigen receptor (TCR)-mediated activation. In T cell variants expressing progressively lower levels of CD45 (from normal to undetectable), CD45 expression was inversely related to spontaneous tyrosine phosphorylation of multiple proteins, including the TCR zeta chain, and was directly correlated with TCR-driven phosphoinositide hydrolysis. The Ca2+ response in these cells was altered in an unexpected fashion. Unlike wild-type cells, stimulated CD45- cell populations did not manifest an early increase in intracellular Ca2+, but did exhibit a delayed and gradual increase in mean intracellular Ca2+. Computer-aided fluorescence imaging of individual cells revealed that CD45- cells experienced late Ca2+ oscillations that were not blocked by removal of extracellular Ca2+. CD45 revertants had the signaling properties of wild-type cells. Thus, CD45 has a profound influence on both TCR-mediated signaling and phosphotyrosine homeostasis, and its loss reveals a novel role for this tyrosine phosphatase in Ca2+ regulation.

Animals↗
PubMed1992

High percentage of CD8+, Leu-7+ cells in rheumatoid arthritis synovial fluid.

OBJECTIVE: While analyzing the phenotype of the synovial fluid mononuclear cells (SFMC) clustered about dendritic cells in rheumatoid arthritis (RA) joint effusions, it was noted that most of the clustering cells were CD8+ and coexpressed Leu-7. Therefore, the present study was conducted to investigate the frequency of CD8+, Leu-7+ cells in RA SF: METHODS: SFMC from 13 patients with RA and from 12 patients with non-RA inflammatory arthritides were examined for CD8 and Leu-7 expression using 2-color immunofluorescence flow cytometry. RESULTS: RA SFMC had statistically significantly greater percentages of total CD8+ cells, total Leu-7+ cells, and CD8+, Leu-7+ cells, compared with SFMC from the non-RA patients. These RA CD8+, Leu-7+ SFMC had a distinctive electron microscopic appearance compared with CD8+, Leu-7- SFMC. When peripheral blood mononuclear cells (PBMC) from 31 RA patients (including 7 from the SFMC group) were compared with PBMC from 15 normal controls, the percentage of CD8+, Leu-7+ cells was not significantly greater in the RA patients. However, the combination of a modest increase in CD8+, Leu-7+ cells and a decrease in total CD8 cells in RA PBMC altered the composition of the RA CD8 population compared with normal PBMC, such that over 40% of RA peripheral blood CD8 cells coexpressed Leu-7. CONCLUSION: The increased frequency of CD8+, Leu-7+ cells in RA SFMC may arise from the fact that a high percentage of the CD8+ PBMC in RA patients are also Leu-7+. This altered composition of CD8 cells in RA SF may have a role in the pathogenesis of the disease.

Antigens, Differentiation↗
PubMed1991

TV and ECT.

Explore the source record for details and available documents.

Depressive Disorder↗
PubMed1991

Nursing care in electroconvulsive therapy.

Psychiatric nursing care for the electroconvulsive therapy (ECT) patient has evolved from a traditional supportive and adjunctive practice to the current practice of independent and collaborative nursing actions. The nurse's multifaceted role is enacted by providing education and support, performing pretreatment assessments, monitoring the procedure, and observing and interpreting posttreatment patient responses. Areas of future nursing education and research should include the expansion of nursing practice with the ECT patient in the provision of quality nursing care.

Electroconvulsive Therapy↗
PubMed1991

Diagnostic peritoneal lavage as an indicator for therapeutic surgery.

Diagnostic peritoneal lavage (DPL) has been reported to be extremely accurate in identifying intra-abdominal injury. Many studies, however, fail to indicate clearly if the procedure is helpful in determining which patients require truly therapeutic surgical intervention, because not all injuries need such surgery. In this study the authors reviewed the charts of 174 patients with blunt abdominal trauma and, by applying strict criteria to define a therapeutic laparotomy, sought to determine, retrospectively, whether DPL was useful for indicating the need for therapeutic surgery. Although 94% of patients with positive findings from DPL underwent a laparotomy, only 65% underwent one that was clearly of therapeutic value. Although other factors may have partially contributed to the discrepancy between these results and those generally referred to in the trauma literature, this study suggests that criteria providing a strict definition of a therapeutic laparotomy must be universally applied when analysing the value of DPL.

Abdominal Injuries↗
PubMed1990

In vitro maturation and encapsidation of the DNA of transposable Mu-like phage D108.

Mu and D108 are related, temperate, transposable coliphages with unusual modes of DNA replication (transposition) and virion DNA maturation. These double-stranded DNA genomes replicate intrachromosomally and are matured and encapsidated linked to DNA sequences flanking the dispersed, integrated phage genomes. We have developed an in vitro system that employs crude lysates prepared from cells late in the Mu lytic cycle and that is proficient for both maturation and encapsidation of D108 DNA. Different forms of phage DNA were packaged at different efficiencies, with a circular pSC101::D108cts10 plasmid being most efficient, linearized plasmid less so, and mature virion DNA a poor substrate. The addition of purified D108 Ner protein to the reaction had no effect, whereas D108 repressor (c protein) inhibited the reaction. Escherichia coli integration host factor and D108 transposase proteins exerted an inhibitory effect on circular DNA substrates but had little effect on linear DNA packaging. This in vitro system, coupled with that developed for transposition, can now be used to biochemically dissect the protein and substrate requirements of these phages' DNA maturation pathway and the nature of the molecular switch between DNA transposition and encapsidation.

Bacteriophage mu↗
PubMed1990

Intimate association of Thy-1 and the T-cell antigen receptor with the CD45 tyrosine phosphatase.

Immunoprecipitation of Thy-1 from Triton X-100 detergent lysates of surface-iodinated and chemically cross-linked T cells precipitated at least five major and discrete bands. Four of these bands were identified as Thy-1, CD45 (a transmembrane tyrosine phosphatase), a major histocompatibility complex-encoded class I molecule, and beta 2-microglobulin. Similar analyses revealed that CD45 was coprecipitated from lysates of cross-linker-treated cells by antibodies to the T-cell antigen receptor (TCR). The same pattern of coprecipitated bands was observed when digitonin was used to lyse untreated cells. Immunoprecipitation of Thy-1 or the TCR from lysates of cross-linked T cells precipitated CD45 tyrosine phosphatase activity. Calculations based upon the amounts of coprecipitated enzymatic activity or TCR zeta chain indicate that a substantial fraction of Thy-1 and TCR complexes can be cross-linked to CD45. These data support a model in which the dependence of Thy-1 signaling on TCR coexpression is due to their common interaction with a tyrosine phosphatase and provide a possible structural basis for the influence of CD45 on TCR-mediated signaling.

Animals↗
PubMed1990

Computed tomography of abdomen (CTA) in management of blunt abdominal trauma.

We reviewed our initial 2-year experience utilizing CT of the abdomen (CTA) in the management of blunt abdominal trauma. Thirty-four of 176 patients (19%) admitted with this diagnosis during 1987-88 underwent CTA as part of their initial evaluation. All patients were hemodynamically stable. Of the 34 CTA's, 15 were negative and the remaining 19 showed positive findings. When the CTA was negative, it was correct in 14 of 15 cases (93%). One case of a perforated jejunum was missed. Of the 19 positive CTA's, 12 cases were treated by observation. The CTA diagnosed a variety of intra- and extraperitoneal injuries which were successfully managed nonoperatively. It, however, missed findings in two cases. Seven of 19 positive CTA cases underwent laparotomy. CTA missed findings in four of these cases. These errors may have been related to the quality of the CTA technique which was subsequently assessed to be suboptimal. When positive, CTA was correct in 13 of 19 cases (68%). The overall accuracy rate was 79% (27 of 34). Subsequent review of the CT scans, however, improved the accuracy rate to 88% (30 of 34). CTA was found to be a valuable adjunct to clinical monitoring in the management of blunt abdominal trauma. However, if the utilization of CTA does not include appropriate patient selection, standardized CTA technique, and accurate radiologic interpretation, there is a significant potential for serious error.

Abdominal Injuries↗
PubMed1987

The implementation of postgraduate training programs through state and local resources.

A profile of implementation strategies for funding postgraduate training programs using local or state resources is described. The need for those implementation strategies as well as basic principles for successful implementation is documented. Two programs are briefly described--a University Affiliated Program (UAP) in western New York and a UAP in Missouri--as the basis for generating implementation strategies. Finally a discussion is provided reviewing the strengths and weaknesses of these strategies.

Developmental Disabilities↗
PubMed1987

Nutrition knowledge in the obese and overweight.

A 20-question multiple choice questionnaire on nutrition knowledge, health care and exercise was developed and validated (Cronbach alpha 0.83). When applied to a population of the obese and overweight, these individuals scored well (63.5 +/- 1.4 per cent) compared to other hospital patients (50.2 +/- 1.7 per cent), and out-patients (47.7 +/- 2.3 per cent). There was no difference between scores in patients presenting to a hospital clinic (who were heavier) and those presenting in the community. Even allowing for age and sex, the obese and overweight scored better than other groups (P less than 0.005). There was no relationship between knowledge score and weight. A group of overweight patients with non-insulin-dependent diabetes mellitus scored poorly (42.3 +/- 2.3 per cent). From this study it was apparent that good nutrition and health care knowledge is not necessarily related to good weight control, other factors seem limiting in this sample. The questionnaire itself may be used to assess whether change in knowledge following nutrition education is related to weight loss.

Adult↗
PubMed1985

Accident-injury organization: Canadian overview.

Trauma from motor vehicle accidents is a major health-care problem, resulting in enormous economic losses to the country, and is second only to heart disease as a reason for hospitalization in Canada. Funding fro research and accident-injury programs is critically low. National and provincial trauma registries must be developed to provide data that can be used appropriately to plan and monitor the strategy of accident health-care and prevention programs. Manitoba, which has in place a trauma registry, has a province-wide trauma system comprising two comprehensive trauma units and seven regional centres located strategically in the catchment areas of the major centres. A comparison of the performance of this system with that of hospitals in Baltimore has shown that the Manitoba system provides an equal level of care. The author recommends that a trauma system be established that a trauma system be established in regions of one to two million population. Each region should have one to three comprehensive trauma services and a number of regional trauma services, each strategically located. With appropriate funding for trauma care, the proposed system would pay for itself.

Accident Prevention↗
PubMed1984

Surgery in the resuscitation of critically injured patients.

Immediate surgery is essential to resuscitate and save 5% to 10% of those suffering life-threatening trauma. Recently, emergency room surgery has been proposed as the procedure to follow in stabilizing such patients. Over a 3-year period, 41 moribund patients were treated by the trauma service at the Health Sciences Centre in Winnipeg. All were managed in the main operating theatre following a "crash protocol" for immediate surgery. Twenty-three patients arrived in cardiac arrest or with an unrecordable blood pressure; of these, 4 (17%) survived. Eighteen patients had a blood pressure of 70 mm Hg systolic or less and failed to respond to massive O positive blood transfusion; of these, 14 (77%) survived. The mix of mode of injury and injury severity scoring is important to compare results from within and between centres. The author's experience indicates that the use of a high-priority crash protocol for managing moribund patients with life-threatening traumatic injury in the main operating room provides a standard of care equal to or better than that reported for emergency room surgery.

Adolescent↗
PubMed1982

Diaphragmatic rupture due to blunt abdominal trauma.

Twenty-two instances of diaphragmatic rupture secondary to blunt thoracoabdominal trauma were seen at the Trauma Unit of the Health Sciences Centre, Winnipeg, Manitoba, Canada during a 30 year period. Diaphragmatic laceration occurred in the right leaf in 11, in the left in ten, and in both sides in one instance. In 14, the diagnosis was made and repair effected within 24 hours of presentation. Seven were diagnosed and treated from three days to several years after the injury. Two patients died soon after admission. They were victims of multiple intra-abdominal as well as intrathoracic injuries. Repair was generally effected through a laparotomy during the immediate post-traumatic period. Thoracotomy was used in those diagnosed after the latent interval. The diagnosis of diaphragmatic disruption should be considered in any patient suffering from blunt thoracoabdominal trauma. Usually a roentgenogram of the chest will confirm the suspected injury. In contradistinction to most of the reported series, our experience indicates that right diaphragmatic injuries are more common than what is usually thought.

Abdominal Injuries↗