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Biomedical subjects

M J Burns

Publications and source records attributed to M J Burns.

At least 37 records · Page 2Linked to original sources
PubMed1997

Another hot tub hazard. Toxicity secondary to bromine and hydrobromic acid exposure.

We describe the clinical course of two patients who developed acute pneumonitis followed by reactive airways dysfunction syndrome after bathing in a hot tub. Additional findings were present and suggested that exposure to a corrosive agent was responsible. Bromine and hydrobromic acid generated from a widely used water disinfectant were implicated as the underlying cause. Physicians should be alert to the possibility that such exposures may initiate or exacerbate inflammatory pulmonary disease.

Acute Disease↗
PubMed1995

Borrelia burgdorferi upregulates expression of adhesion molecules on endothelial cells and promotes transendothelial migration of neutrophils in vitro.

The accumulation of leukocytic infiltrates in perivascular tissues is a key step in the pathogenesis of Lyme disease, a chronic inflammatory disorder caused by Borrelia burgdorferi. During an inflammatory response, endothelial cell adhesion molecules mediate the attachment of circulating leukocytes to the blood vessel wall and their subsequent extravasation into perivascular tissues. Using cultured human umbilical vein endothelial cells (HUVEC) in a whole-cell enzyme-linked immunosorbent assay, we demonstrated that B. burgdorferi activated endothelium in a dose- and time-dependent fashion as measured by upregulation of the adhesion molecules E-selectin, vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1). As few as one spirochete per endothelial cell stimulated increased expression of these molecules. Expression of E-selectin peaked after spirochetes and HUVEC were coincubated for 4 h and returned to near-basal levels by 24 h. In contrast, expression of VCAM-1 and ICAM-1 peaked at 12 h and remained elevated at 24 h. HUVEC monolayers cultured on acellular amniotic tissue were used to investigate the consequences of endothelial cell activation by spirochetes. After incubation of HUVEC-amnion cultures with B. burgdorferi, subsequently added neutrophils migrated across the endothelial monolayers. This process was mediated by E-selectin and by CD11/CD18 leukocytic integrins. The extent of migration depended on both the number of spirochetes used to stimulate the HUVEC and the length of the coincubation period. These results raise the possibility that B. burgdorferi induces a host inflammatory response and accompanying perivascular damage through activation of vascular endothelium.

Borrelia burgdorferi Group↗
PubMed1993

The value of baseline chest radiograph reports in the care of elderly patients in an emergency department.

The authors used a before/after research design to determine the impact of written reports of baseline chest radiographs (CXRs) on the care of elderly patients during 48 emergency department visits. Internal medicine housestaff completed questionnaires that included inquiries about their treatment plans for the patients both before and after they reviewed reports of baseline CXR results. The investigators compared these answers to determine the proportion of patients for whom baseline CXR reports changed patient management. In addition, three faculty reviewers used the nominal group process, a consensus analysis approach, to measure treatment changes and to estimate benefit to the patients from the alterations in management. The housestaff indicated that written baseline CXR reports caused them to change treatment plans during only 2 (4%) of the 48 visits. In both cases, they provided aggressive treatment for congestive heart failure because of baseline CXR results. The faculty reviewers could find only one case in which baseline CXR findings might have changed their management plans. Moreover, they were not convinced that the treatment changes indicated by the housestaff actually benefitted the patients. These results suggest that written reports of baseline CXRs do not improve the care of acutely ill patients in an emergency department setting.

Aged↗
PubMed1993

Soaring suppurative sea shells from the sea shore: Pseudomonas aeruginosa and Klebsiella pneumoniae septic arthritis after a marine sea shell injury.

Septic arthritis is the most important diagnosis to consider in patients presenting with acute monarticular arthritis. We present the case of an eight-year-old girl who developed a Pseudomonas aeruginosa and Klebsiella pneumoniae septic arthritis of her knee following an injury with a marine sea shell. After treatment with antibiotics and arthroscopic irrigation, she had good functional recovery. We could find no previously reported cases of Pseudomonas aeruginosa or Klebsiella pneumoniae septic arthritis resulting from an injury in a marine environment. The pathogenesis and treatment of septic arthritis and infection following marine injuries are discussed.

Arthritis, Infectious↗
PubMed1992

E-selectin (endothelial-leukocyte adhesion molecule-1) is not required for the migration of neutrophils across IL-1-stimulated endothelium in vitro.

Treatment of vascular endothelial cells with inflammatory cytokines stimulates surface expression of E-selectin (previously known as endothelial-leukocyte adhesion molecule-1) and promotes the transendothelial migration of neutrophils. To assess participation of E-selectin in cytokine-mediated neutrophil migration, an in vitro model consisting of monolayers of human umbilical vein endothelial cells (HUVEC) grown on amniotic connective tissue was used. When HUVEC-amnion cultures were stimulated for 4 h with relatively low concentrations of IL-1 (0.1 to 0.15 U/ml), mAb BB11 or H18/7 to E-selectin partially inhibited migration of subsequently added neutrophils. However, when the cultures were stimulated with 15 U/ml of IL-1 for 4 or 24 h, little to no inhibition was observed. mAb to E-selectin also failed to inhibit migration of neutrophils across HUVEC-amnion cultures treated with low doses of IL-1 when the leukocytes were additionally stimulated by the chemoattractant leukotriene B4. In contrast, migration of neutrophils across IL-1-treated HUVEC was profoundly inhibited by mAb to CD11/CD18 leukocytic integrins under all conditions tested. Results of these studies suggest that participation of E-selectin is not essential for migration of neutrophils across cytokine-stimulated HUVEC in vitro; rather, E-selectin can be bypassed in favor of CD11/CD18-dependent mechanisms under appropriate circumstances.

Antibodies, Monoclonal↗
PubMed1992

A comparison of HIV-1, HBV, and HTLV-I/II seroprevalence rates of injured patients admitted through California emergency departments.

STUDY OBJECTIVE: To determine the seroprevalence rates of hepatitis B virus (HBV) and human T-lymphotropic virus (HTLV-I/II) and to compare these rates with the HIV-1 seroprevalence rate in a sample of injured patients admitted through ten California emergency departments. DESIGN: Prospective blinded testing for serologic markers for HBV, HTLV-I/II, and HIV-1 on routinely collected blood samples. SETTING: Ten California hospitals were chosen to reflect geographic and demographic diversity. TYPE OF PARTICIPANTS: All injured adult patients who were admitted to a participating hospital through the ED during consecutive three-month periods from June through November 1989. MEASUREMENTS: Serum samples were tested for HIV-1 antibody, HTLV-I/II antibody, and hepatitis B surface antigen (HBsAg) using standard methods. Mann-Whitney U tests, chi 2 tests for independence, sign tests, chi 2 tests for goodness of fit, and logistic regression were used as appropriate. RESULTS: Seroprevalence rates were as follows: HBV, 2.6% (57 of 2,209); HTLV-I/II, 2.0% (46 of 2,262); and HIV-1, 1.4% (31 of 2,264). CONCLUSION: The seroprevalence rate of HBV was slightly higher than that of HIV-1 in this sample of injured patients. Mortality estimates suggest, however, that HBV and HIV-1 pose roughly similar risks to emergency personnel, although the risk of HBV infection can be markedly reduced by vaccination. The data from this and other studies suggest that the ED incidence of HTLV-I/II in United States is low. The relative health risks to emergency personnel from HTLV-I/II appear to be minimal at this time.

California↗
PubMed1991

Resting electrocardiograms as baseline tests: impact on the management of elderly patients.

PURPOSE: We evaluated management decisions of house staff in a university hospital emergency department (ED) to determine the impact of baseline electrocardiogram (ECG) results on the care of elderly patients. SUBJECTS AND METHODS: The study employed a prospective before-after research design. The subjects included internal medicine house staff assigned to the ED and the 47 elderly patients treated by them during 58 ED visits. The measures of impact on patient care included how often and in what ways comparison of baseline and ED ECG results changed the house staff's diagnostic impressions and treatment plans. To determine changes, we asked house staff to indicate their impressions and management plans before and after comparing baseline and ED ECG results. In addition, a panel of faculty members used a modification of the nominal group process to determine treatment changes and to estimate benefit to patients from the changes. RESULTS: House staff indicated that baseline ECG results led them to change diagnostic impressions during 13 (22%) and treatment plans during eight (14%) of the 58 visits. Six of the patients benefited from the treatment changes. The faculty judges indicated that baseline ECG findings would have altered their diagnostic impressions in eight (14%) and treatment decisions in three (5%) of the 58 cases, one of which would have benefited from the change. All patients for whom there were changes of impression or plan had prior histories of cardiovascular disease. CONCLUSION: We conclude that baseline ECGs provide ED house staff with diagnostic information that often leads to changes in management of elderly patients with prior histories of cardiovascular disease. Future studies should evaluate the efficacy of baseline ECGs in patients without such histories.

Aged↗
PubMed1988

Usefulness of ambulatory radionuclide monitoring of left ventricular function early after acute myocardial infarction for predicting residual myocardial ischemia.

Ambulatory radionuclide monitoring of left ventricular function was performed with the nuclear Vest device in 35 patients early after acute myocardial infarction. Patients were evaluated during post-infarction treadmill, other activities that included mental stress and cold pressor challenge, and with stress thallium imaging and cardiac catheterization. Of the 35 patients evaluated, 14 had ischemic responses on treadmill testing and 21 had negative responses. By contrast, 20 had redistribution by thallium imaging suggesting ischemia. Vest studies demonstrated 56 responses suggestive of ischemia in 23 patients. Twenty-two occurred during exercise and 13 with mental stress. Seventy-five percent were silent and only 39% had associated electrocardiographic changes. Vest responses were compared in patients whose thallium scan was indicative of ischemia (thallium-positive) and those without ischemia (thallium-negative). Ejection fraction was higher in the thallium-positive group (0.52 +/- 0.11), as compared with thallium-negative patients (0.44 +/- 0.1). With exercise, ejection fraction decreased for the thallium-positive patients from 0.52 +/- 0.11 to 0.40 +/- 0.09 at peak exercise. For thallium-negative patients, ejection fraction changes were not significant. During mental stress, ejection fraction decreased from 0.51 +/- 0.11 to 0.45 +/- 0.12 for thallium-positive patients while thallium-negative patients were unchanged. Vest-measured decreases in ejection fraction of greater than or equal to 5 units during exercise were highly sensitive (90%), specific (73%) and predictive (82%) of a positive thallium scan. The same response for mental stress was specific (87%) and predictive (85%) of a positive scan result.(ABSTRACT TRUNCATED AT 250 WORDS)

Cold Temperature↗
PubMed1988

Hemodynamic effects of intravenous metoprolol in acute myocardial infarction: the role of anatomic subsets in predicting patient response.

The acute effects of intravenous metoprolol were evaluated in 30 patients with myocardial infarction by means of serial hemodynamic and radionuclide measurements of left ventricular function. Within 1 hour of completion of the metoprolol dosing, 90% of the patients underwent cardiac catheterization to define anatomy and to assess patients for interventional therapy; the remainder had catheterization by 72 hours. All patients tolerated intravenous metoprolol without significant side effects. Patient responses to therapy were divided into two groups based on the angiographic findings. At catheterization, all group 1 patients had visible collaterals to or a patent vessel supplying the vascular distribution of the infarction. All group 2 patients had occluded coronary arteries without evidence of collaterals to the infarct zone. Group 1 (n = 13) improved both systolic and diastolic left ventricular function (mean ejection fraction [EF] = 46% to 55%, peak filling rate [PFR] = 2.1 to 3.2 Edv/sec), while group 2 (n = 17) patients were unchanged (EF = 43% to 42%, PFR = 2.0 to 1.9). Patient characteristics and time to treatment were similar in both groups, as were the hemodynamic effects of metoprolol. Heart rate decreased 20% in group 1 and 22% in group 2 and cardiac output fell 22% in group 1 and 32% in group 2. Acute improvement in ventricular function in these patients appears to be closely related to the coronary anatomy, and in those with flow to the infarct zone, intravenous metoprolol may be effective in preserving left ventricular function.

Administration, Oral↗
PubMed1988

Comparable effects of intravenous nitroglycerin and intravenous nitroprusside in acute ischemia.

Forty patients with unstable angina were randomized to therapy with intravenous nitroglycerin (NTG) or nitroprusside (NTP). Invasive hemodynamic measurements were compared in both treatment groups and were used in concert with serial radionuclide monitoring of left ventricular function as patients were titrated to a therapeutic dose. Of the 22 patients randomized to intravenous NTG, there were 18 responders. Cardiac output significantly increased 28%, from 5.0 to 6.5 L/min at maximum effect. Mean pulmonary capillary wedge pressure (PCWP) decreased from 19 to 12 mm Hg. Mean arterial pressure decreased 10% and heart rate was unchanged (82 beats/min pre-treatment, 81 beats/min post-treatment). Radionuclide determined ejection fraction (EF) increased an average of 0.13, from 0.45 to 0.58. Peak filling rate paralleled increases in EF, increasing from 2.2 to 3.4 EDV/sec at peak level. Hemodynamic and radionuclide responses in the intravenous NTP group were compared to those with NTG. Of 18 patients randomized to NTP, 15 responders increased cardiac output from 5.1 to 6.8 L/min, a 35% increase. PCWP was 18 mm Hg at baseline and 10 mm Hg at peak effect. Mean arterial pressure decreased 13%, which was not significantly different from the NTG group. Heart rate response was identical to that in the NTG group. Ejection fraction increased an average of 0.17, from 0.43 to 0.60. Similar improvements were seen in peak filling rate (2.09 to 3.3 EDV/sec). There were no baseline differences between the NTG and NTP groups. In these patients NTG and NTP demonstrated equal efficacy, with the majority of patients showing substantial improvement in acute hemodynamics and left ventricular function with either agent.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1984

Specific inhibition of in vitro lymphocyte transformation by an anti-pan T cell (gp67) ricin A chain immunotoxin.

The toxin A chain of ricin has been conjugated by a disulfide bond to a murine monoclonal antibody that recognizes the gp67kD antigen present on 95% of peripheral T lymphocytes. The immunotoxin retains both functions of its component parts: it binds to human peripheral blood lymphocytes, and it inhibits protein synthesis in a cellfree reticulocyte system. The immunotoxin has been evaluated for its ability to inhibit in vitro T lymphocyte transformation. In the presence of 20 mM NH4Cl, the immunotoxin decreases lymphocyte proliferation in response to phytohemagglutinin to less than 8% of untreated controls. The proliferative response in mixed lymphocyte culture and the development of allocytotoxic T cells is also dramatically inhibited by this immunotoxin. Monoclonal antibody alone does not inhibit these responses. Specificity of the immunotoxin has been established: the effect of the immunotoxin can be blocked by unconjugated monoclonal antibody, but not by a control monoclonal antibody that recognizes another T lymphocyte differentiation antigen or by a control monoclonal antibody that does not recognize human peripheral blood leukocytes. Treatment of human bone marrow cells with the immunotoxin preserves hematopoietic progenitor cells, as measured by granulocyte-macrophage, erythroid, and multipotential hematopoietic progenitor cell assays. These results indicate that an anti-pan T lymphocyte-ricin A chain immunotoxin is an effective agent against immunocompetent T lymphocytes in vitro, and may be an effective agent for use in clinical bone marrow transplantation.

Animals↗
PubMed1979

Wound infection associated with Vibrio alginolyticus.

A 42-year-old man had an infected ulcerated lesion of the anterior aspect of the right lower extremity. Vibrio alginolyticus was twice isolated from the lesion. Emphasis is placed on the clinical and laboratory characteristics of this organism and its differentiation from other halophilic vibrios.

Adult↗