Role of L-selectin in physiological manifestations after burn and smoke inhalation injury in sheep.
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The effects of a monoclonal antibody against L-selectin [leukocyte adhesion molecule (LAM)1-3] on microvascular fluid flux were determined in conscious sheep subjected to a combined injury of 40% third-degree burn and smoke inhalation. This combined injury induced a rapid increase in systemic prefemoral lymph flow (sQlymph) from the burned area and a delayed-onset increase in lung lymph flow. The initial increase in sQlymph was associated with an elevation of the lymph-to-plasma oncotic pressure ratio; consequently, it leads to a predominant increase in the systemic soft tissue permeability index (sPI). In an untreated control group, the increased sPI was sustained beyond 24 h after injury. Pretreatment with LAM1-3 resulted in earlier recovery from the increased sPI, although the initial responses in sQlymph and sPI were identical to those in the nontreatment group. The delayed-onset lung permeability changes were significantly attenuated by pretreatment with LAM1-3. These findings indicate that both leukocyte-dependent and -independent mechanisms are involved in the pathogenesis that occurs after combined injury with burn and smoke inhalation. (+info)
Early alterations of lung injury following acute smoke exposure and 21-aminosteroid treatment.
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In a simulated fire-related smoke exposure protocol, New Zealand white rabbits were utilized to investigate the potential effects of the 21-aminosteroid (lazaroid) analog U75412E on the early events of acute lung injury. Inhalation of a total of 1.6 mg/kg U75412E aerosolized at a rate of 1.53 mg/min at 0.5 hr after smoke exposure significantly attenuated the extent of lung injury at 1 hr, as evidenced by decreased bronchoalveolar lavage (BAL) concentration of total protein, 6-keto-prostaglandin F1-alpha, and blood gas defect. Histopathologic examination demonstrated that the lazaroid significantly attenuated smoke-induced lung injury as evidenced by a decrease in wet lung/body weight ratio, necrosis, and sloughing of airway epithelial cells. Electron microscopy showed that the lazaroid decreased smoke-induced interstitial edema and the vacuolization of alveolar type II epithelium (21.6 +/- 9.7 vs 8.5 +/- 3.6 vacuoled blebs/cell, smoke only vs smoke + lazaroid). However, U75412E did not attenuate smoke-induced changes in BAL concentration of tumor necrosis factor-alpha, total cell count, and granulocyte percentage. These observations suggest that U75412E may exert its action through cooperative mechanisms, such as the modulation of arachidonic acid metabolism, in addition to its characterized antioxidative effects. (+info)
Increased group IV cytosolic phospholipase A2 activity in lungs of sheep after smoke inhalation injury.
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Increased phospholipase A2 (PLA2) activity was measured in cytosolic fractions of lungs from sheep exposed to smoke from burning cotton or to synthetic smoke consisting of carbon and acrolein, a cotton smoke toxin. Three peaks of PLA2 activity were identified by heparin-Sepharose chromatography. The heparin-nonbinding PLA2 activity was twofold higher in the extracts from lungs exposed to smoke than in normal lungs. This activity was identified as the group IV 85-kDa cytosolic PLA2 (cPLA2). The activities of the forms of PLA2 that bound to heparin did not change after smoke exposure. Those activities showed a pH optimum of 9.0, required a millimolar Ca2+ concentration for full activity, and were inhibited by 5 mM dithiothreitol. One activity eluted at an NaCl concentration typical for group Ib and V PLA2 and had the expected substrate specificity. The other form of lung PLA2 that bound heparin was a group II PLA2. Lung myeloperoxidase activity increased progressively with increased exposure to smoke. cPLA2 was identified in sheep neutrophils. With 30 breaths of smoke exposure, there was an increase in cPLA2 activity without a difference in immunoreactivity on Western blot, indicating that the increased activity was not due to increased amounts of protein. In conclusion, smoke induces increases in resident lung cell cPLA2 activity that is likely responsible for eicosanoid production, leading to lung inflammation and bronchoconstriction. (+info)
The "Let's Get Alarmed!" initiative: a smoke alarm giveaway programme.
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OBJECTIVES: To reduce fires and fire related injuries by increasing the prevalence of functioning smoke alarms in high risk households. SETTING: The programme was delivered in an inner London area with above average material deprivation and below average smoke alarm ownership. The target population included low income and rental households and households with elderly persons or young children. METHODS: Forty wards, averaging 4000 households each, were randomised to intervention or control status. Free smoke alarms and fire safety information were distributed in intervention wards by community groups and workers as part of routine activities and by paid workers who visited target neighbourhoods. Recipients provided data on household age distribution and housing tenure. Programme costs were documented from a societal perspective. Data are being collected on smoke alarm ownership and function, and on fires and related injuries and their costs. RESULTS: Community and paid workers distributed 20,050 smoke alarms, potentially sufficient to increase smoke alarm ownership by 50% in intervention wards. Compared with the total study population, recipients included greater proportions of low income and rental households and households including children under 5 years or adults aged 65 and older. Total programme costs were 145,087 Pounds. CONCLUSIONS: It is possible to implement a large scale smoke alarm giveaway programme targeted to high risk households in a densely populated, multicultural, materially deprived community. The programme's effects on the prevalence of installed and functioning alarms and the incidence of fires and fire related injuries, and its cost effectiveness, are being evaluated as a randomized controlled trial. (+info)
House fire injury prevention update. Part II. A review of the effectiveness of preventive interventions.
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OBJECTIVE: To evaluate and summarize the house fire injury prevention literature. METHODS: MEDLINE (1983 to March 1997) was searched by keyword: fire, burn, etiology, cause, prevention, epidemiology, and smoke detector/alarm. ERIC (1966 to March 1997) and PSYCLIT (1974 to June 1997) were searched by keyword: as above, and safety, skills, education, and training. Other sources included references of retrieved publications, review articles, and books; Injury Prevention hand search; government documents; and internet sources. Sources relevant to residential fire injury prevention were selected, evaluated, and summarized. RESULTS: Forty three publications were selected for review, including seven randomized controlled trials, nine quasiexperiments, two natural experiments, 21 prospective cohort studies, two cross sectional surveys, one case report, and one program evaluation. These studies examined the following types of interventions: school (9), preschool (1), and community based educational programs (5); fire response training programs for children (7), blind adolescents (2), and mentally retarded adults (5) and children (1); office based counseling (4); home inspection programs (3); smoke detector giveaway campaigns (5); and smoke detector legislation (1). CONCLUSIONS: This review of house fire prevention interventions underscores the importance of program evaluation. There is a need for more rigorous evaluation of educational programs, particularly those targeted at schools. An evidence based, coordinated approach to house fire injury prevention is critical, given current financial constraints and the potential for program overload for communities and schools. (+info)
Systematic review of controlled trials of interventions to promote smoke alarms.
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AIMS: To evaluate the effects of promotion of residential smoke alarms. METHODS: Electronic databases, conference proceedings, and bibliographies were systematically searched, and investigators and organisations were contacted, in order to identify controlled trials evaluating interventions designed to promote residential smoke alarms. The following were assessed: smoke alarm acquisition, ownership, and function; fires; burns; and fire related injuries. Odds ratios (OR) were estimated by meta analysis of randomised trials. RESULTS: A total of 26 trials were identified, of which 13 were randomised. Overall, counselling and educational interventions had only a modest effect on the likelihood of owning an alarm (OR = 1.26; 95% confidence interval (CI): 0.87 to 1.81) or having a functional alarm (OR = 1.19; 95% CI: 0.85 to 1.66). Counselling as part of primary care child health surveillance had greater effects on ownership (OR = 1.93; 95% CI: 1.04 to 3.58) and function (OR = 1. 72; 95% CI: 0.78 to 3.78). Results were sensitive to trial quality, however, and effects on fire related injuries were not reported. In two non-randomised trials, direct provision of free alarms significantly increased functioning alarms and reduced fire related injuries. Media and community education showed little benefit in non-randomised trials. CONCLUSION: Counselling as part of child health surveillance may increase smoke alarm ownership and function, but its effects on injuries are unevaluated. Community smoke alarm give away programmes apparently reduce fire related injuries, but these trials were not randomised and results must be interpreted cautiously. Further efforts to promote smoke alarms in primary care or through give away programmes should be evaluated by adequately designed randomised controlled trials measuring injury outcomes. (+info)
Profile of the pediatric burn patient at the Schneider Children's Medical Center of Israel.
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BACKGROUND: Burn trauma occurs mostly in young children. Burn injury in the pediatric age group has multiple-aspect sequelae. OBJECTIVES: To characterize the profile of the injured pediatric burn patient, thus targeting the most vulnerable pediatric group. METHODS: Between 1 January and 31 December 1996, a total of 9,235 pediatric patients were admitted for various traumatic injuries (burns, lacerations, fractures, etc.) to the Emergency Medicine Department of Schneider Children's Medical Center. We conducted a retrospective study of the patients' charts, including demographic data, which were stored in a computerized database, for statistical evaluation. The characteristics of pediatric burn patients were examined and compared with other pediatric trauma patients. RESULTS: Of the total patient population, 282 (3.1%) suffered from burns (37% females, 63% males). The most frequent burn injury was scald burn (58%). The pediatric group that was most exposed to burns was 13-18 month old males. CONCLUSIONS: Having identified the high risk group among the pediatric burn patients, we suggest that prevention programs be directed towards this group in order to reduce further risk of burn injury. (+info)
Prior exposure to aged and diluted sidestream cigarette smoke impairs bronchiolar injury and repair.
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The bronchiolar injury/repair response to naphthalene (NA) in mice includes acute distal airway epithelial injury that is followed by epithelial proliferation and redifferentiation, which result in repair of the epithelium within 14 days. To test whether prior exposure to aged and diluted sidestream cigarette smoke (TS) would alter the injury/repair response of the airway epithelium, adult mice were exposed to either filtered air (FA) or smoke for 5 days before injection with either corn oil carrier (CO) or naphthalene. Mice were killed 1 and 14 days after naphthalene injury. Lung and lobar bronchus were examined and measured using high-resolution epoxyresin sections. The control group (FACOFA) that was exposed to filtered air/corn oil/filtered air contained airway epithelium similar to untreated controls at all airway levels. The group exposed to tobacco smoke/corn oil/filtered air (TSCOFA) contained some rounded cells in the small airways and some expansion of the lateral intercellular space in the larger airways. Necrotic or vacuolated cells were not observed. As expected, the epithelium in the group exposed to filtered air/naphthalene/filtered air (FANAFA) contained many light-staining vacuolated Clara cells and squamated ciliated cells within distal bronchioles during the acute injury phase. Repair (including redifferentiation of epithelial cells and restoration of epithelial thickness) was nearly complete 14 days after injury. The extent of Clara cell injury, as assessed in lobar bronchi, was not different between the four groups. Although the FANAFA group contained greater initial injury in the distal airways at 1 day, the group exposed to tobacco smoke/naphthalene/filtered air (TSNAFA) had the least amount of epithelial repair at 14 days after naphthalene treatment; many terminal bronchioles contained abundant squamated undifferentiated epithelium. We conclude that tobacco smoke exposure prior to injury (1) does not change the target site or target cell type of naphthalene injury, since Clara cells in terminal bronchioles are still selectively injured; (2) results in slightly diminished acute injury from naphthalene in distal bronchioles; and (3) delays bronchiolar epithelial repair. (+info)