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At least 19 recordsLinked to original sources
PubMed1983

Fire ant venom hypersensitivity. I. Comparison of fire ant venom and whole body extract in the diagnosis of fire ant allergy.

Levels of IgE antibody to fire ant whole body extract (FA-WBE) and fire ant venom (FAV) were evaluated in 60 patients with clinical histories of fire ant sting hypersensitivity and 11 frequently stung individuals without significant clinical reactivity to fire ant. An overlap of levels of IgE antibody to FA-WBE and FAV was seen between groups of patients with increasingly severe clinical reactivity; however, the group mean IgE antibody level of patients without significant clinical reactivity differed markedly from the group means of patients with more severe clinical reactivity (p less than 0.001). In 31 patients a good correlation (r = 0.6935) was found comparing FA-WBE IgE antibody level with FA-WBE skin tests, and in 26 patients a good correlation (r = 0.8564) was obtained comparing FAV IgE antibody levels with FAV skin tests. An excellent Spearman rank correlation coefficient (r = 0.9197) was found on comparison of FAV and FA-WBE IgE antibody levels in 71 individuals. Cross-reactivity of FAV and FA-WBE was demonstrated by the ability of these reagents to competitively inhibit the binding of IgE antibody to solid-phase FA-WBE and FAV in the radioallergosorbent test (RAST). From these results we conclude that FAV and FA-WBE both contain relevant allergens important in fire ant-allergic individuals and that skin tests and RAST are both valid as diagnostic tests for fire ant allergy. Finally, there is a good correlation between RAST and skin tests using FA-WBE or FAV as test reagents, since these reagents are highly cross-reactive as demonstrated by their ability to inhibit each other in the RAST.

Adolescent↗
PubMed2001

Correlation between uncoupled conductance-based integrate-and-fire neurons due to common and synchronous presynaptic firing.

We investigate the firing characteristics of conductance-based integrate-and-fire neurons and the correlation of firing for uncoupled pairs of neurons as a result of common input and synchronous firing of multiple synaptic inputs. Analytical approximations are derived for the moments of the steady state potential and the effective time constant. We show that postsynaptic firing barely depends on the correlation between inhibitory inputs; only the inhibitory firing rate matters. In contrast, both the degree of synchrony and the firing rate of excitatory inputs are relevant. A coefficient of variation CV > 1 can be attained with low inhibitory firing rates and (Poisson-modulated) synchronized excitatory synaptic input, where both the number of presynaptic neurons in synchronous firing assemblies and the synchronous firing rate should be sufficiently large. The correlation in firing of a pair of uncoupled neurons due to common excitatory input is initially increased for increasing firing rates of independent inhibitory inputs but decreases for large inhibitory firing rates. Common inhibitory input to a pair of uncoupled neurons barely induces correlated firing, but amplifies the effect of common excitation. Synchronous firing assemblies in the common input further enhance the correlation and are essential to attain experimentally observed correlation values. Since uncorrelated common input (i.e., common input by neurons, which do not fire in synchrony) cannot induce sufficient postsynaptic correlation, we conclude that lateral couplings are essential to establish clusters of synchronously firing neurons.

Animals↗
PubMed1991

Occupational noise exposure and hearing loss in fire fighters assigned to airport fire stations.

The National Institute for Occupational Safety and Health (NIOSH) was requested to conduct a health hazard evaluation (HHE) at a large metropolitan fire department. The request concerned the hearing levels and noise exposures of fire fighters who were assigned to two fire stations serving the international airport. There was concern that these fire fighters were at a greater risk of accruing hearing loss than fire fighters located at other fire stations because of the addition of aircraft noise to their occupational noise exposures. The city also requested that NIOSH investigate other fire stations, not influenced by the airport, for noise exposures and hearing ability among a larger population of the fire fighters. NIOSH investigators conducted noise surveys at five fire stations and examined the hearing ability of 197 fire fighters. The noise surveys consisted of personal noise dosimetry on fire fighters assigned to the fire station for the entire 24-hr tour of duty over 2 consecutive days at each of the five stations. A NIOSH investigator accompanied the fire fighters on their vehicle to log response times and activities. The audiometric examinations were pure-tone, air conduction tests administered according to the Occupational Safety and Health Administration's (OSHA's) hearing conservation amendment. The noise dosimetry results revealed time-weighted averages (TWAs) that ranged from 60 to 82 dBA. However, the levels encountered during Code 3 responses (warning lights, sirens, and air horns) reached 109 dBA for a 1-min time period. The audiometric results showed that the average fire fighter exhibited a characteristic noise-induced permanent threshold shift.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Playing with fire: images of fire on toy packaging.

Despite prevention efforts designed to teach children that fire is not a toy, each year hundreds of children, primarily male, are injured while playing with fire. Mass-produced toys and games shape children's behaviors, and the fire images on toy packaging may send the message that fire is fun rather than dangerous. The purpose of this study was to determine the frequency of male fire-related injuries at our burn center and to investigate the use of fire images in toy packaging. An aisle-by-aisle search was conducted at a national toy store. Toys with fire images on their packaging were identified. Target gender and the setting in which the fire was displayed also were recorded. Only toys with clearly visible flames on their packaging were included. We reviewed our TRACS database from April 1997 to May 1999 for fire-related injuries to children admitted to our institution as a result of playing with fire. Review of toy stores revealed 404 toys with packaging containing fire images. Of these, 97% (393 of 404) were targeted to males. Video games were the leading category of flame-related packaging (208 of 404), followed by toy car/truck displays (84 of 404). Packaging for girls' toys had safe and contained settings, whereas boys' toys used settings that were uncontrolled and associated with speed and weapons. A total of 59 children, 52 males and 7 females, with a mean age of 10 +/- 0.6 years and mean TBSA burn of 12.3 +/- 2.1% were admitted to our facility with fire-related injuries during the study interval. Children imitate life with toys and use play to experiment with new behavior. Boys are receiving a powerful, consistent message from images of fire on toy packaging. These advertisements may help to contribute to the higher incidence of fire-related injuries in boys.

Accident Prevention↗
PubMed2001

Apamin-induced irregular firing in vitro and irregular single-spike firing observed in vivo in dopamine neurons is chaotic.

Dopamine neurons of the substantia nigra often fire action potentials irregularly in vivo, but in vitro fire in a regular, pacemaker-like firing pattern. Bath application of apamin, a blocker of calcium-activated potassium channels, can shift a dopamine neuron from pacemaker-like to irregular firing. To determine whether the irregular firing was caused by intrinsic cellular mechanisms rather than random synaptic input or some other form of noise, spike density functions of interspike interval records were analyzed using non-linear forecasting methods to quantify any non-linear (non-periodic) structure. Intrinsic cellular mechanisms are capable of producing chaotic firing, which is deterministic, non-linear, and loses predictability exponentially with increasing forecast time.To determine whether forecasting spike density functions could reliably measure predictability, forecasting was first applied to spike density functions produced by computer simulations of pacemaker-like, chaotic, and random firing, as well as pacemaker-like and chaotic firing that were randomly synaptically driven. Exponential loss of predictability was successfully detected in both chaotic and randomly driven chaotic firing. Predictability scaled faster than exponentially for random spiking, and linearly (slower than exponentially) for randomly driven pacemaker firing. The method was then applied to experimental records of apamin-induced irregular firing of rat dopaminergic neurons of the substantia nigra in vitro and in vivo. Exponential loss of predictability was detected in both cases, consistent with chaotic firing. Experimental records of pacemaker-like firing in vitro showed linear scaling, consistent with a randomly driven pacemaker. Several schemes for neural encoding of synaptic inputs have been suggested, such as rate codes or temporal codes. However, our results suggest that under some conditions, the irregular firing of dopamine neurons does not reflect the random temporal dynamics of its inputs, but rather the intrinsic, deterministic dynamics of dopamine cells themselves, under the tonic neuromodulatory influence of apamin in vitro and possibly that of an unidentified endogenous modulatory substance in vivo.

Action Potentials↗
PubMed2003

Evaluation of the fire simulation processes of the National Fire Management System's Initial Attack Analysis processor.

The fire simulation processes of the National Fire Management System's (NFMAS) Initial Attack Analysis (IAA) processor were evaluated by conducting two types of sensitivity analysis: one based on a hypothetical set of data to assess IAA's outputs under a wide range of fire input values, and the other using an actual Stanislaus National Forest database to test IAA's validity with a real set of data. The results revealed that IAA's outputs (projected annual number of fires and area burned) were most sensitive, in descending order, to the input values of the fire spread rate, the productivity rates of the suppression forces, and the initial attack time, for all fuel models tested. In contrast, IAA's outputs were extremely insensitive to variations in the fire size at discovery. Changes are necessary in the ways IAA incorporates the fire size at discovery to facilitate the comparison among various fire detection options. The program's "escaped fire situation" analysis was found inadequate, because the projected annual frequencies and final sizes of the simulated escaped fire events produced unacceptable results with the Stanislaus National Forest database. Assigning final sizes to simulated escaped fires according to the fire intensity level in which they are historically expected to occur provides a consistent way of calculation of the projected annual area burned and the consequent cost plus net value change (C + NVC).

Conservation of Natural Resources↗
PubMed2001

Blood carbon monoxide and hydrogen cyanide concentrations in the fatalities of fire and non-fire associated civil aviation accidents, 1991-1998.

Blood samples submitted to the Civil Aeromedical Institute (CAMI) from aviation accident fatalities are analyzed for carbon monoxide (CO), as carboxyhemoglobin (COHb), and hydrogen cyanide, as cyanide (CN(-)). These analyses are performed to establish possible exposure of victims to smoke from in-flight/post-crash fires or to CO from faulty exhaust/heating systems. The presence of both gases in blood would suggest that the victim was alive and inhaled smoke. If only COHb is elevated, the accident (or a death) could be the result of CO contamination of the interior. Information pertaining to blood levels of these gases in aviation fatalities, in relation to the associated accidents, is scattered or not available, particularly with regard to toxicity. Therefore, considering that COHb> or =10% and CN(-)> or =0.25 microg/ml are sufficient to produce some degree of toxicological effects, the necessary information was extracted from the CAMI database. Samples from 3857 fatalities of 2837 aviation accidents, occurring during 1991-1998, were received; 1012 accidents, encompassing 1571 (41%) fatalities, were fire associated, whereas 1820 accidents were non-fire related. The remaining five accidents were of unknown fire status. There were fewer fire related fatalities and associated accidents in the (COHb> or =10% and CN(-)> or =0.25 microg/ml) category than that in the (COHb<10% and CN(-)<0.25 microg/ml) category. No in-flight fire was documented in the former category, but in-flight fires were reported in 14 accidents (18 fatalities) in the latter category. No non-fire accident fatality was found wherein levels of both gases were determined to be at or above the stated levels. There were 15 non-fire accidents with 17 fatalities wherein only COHb (10-69%) was elevated. The present study suggests that aviation fire accidents/fatalities were fewer than aviation non-fire accidents/fatalities and confirms that aviation accidents related to in-flight fires and CO-contaminated interiors are rare.

Accidents, Aviation↗
PubMed1999

Reexamining fire suppression impacts on brushland fire regimes

California shrubland wildfires are increasingly destructive, and it is widely held that the problem has been intensified by fire suppression, leading to larger, more intense wildfires. However, analysis of the California Statewide Fire History Database shows that, since 1910, fire frequency and area burned have not declined, and fire size has not increased. Fire rotation intervals have declined, and fire season has not changed, implying that fire intensity has not increased. Fire frequency and population density were correlated, and it is suggested that fire suppression plays a critical role in offsetting potential impacts of increased ignitions. Large fires were not dependent on old age classes of fuels, and it is thus unlikely that age class manipulation of fuels can prevent large fires. Expansion of the urban-wildland interface is a key factor in wildland fire destruction.

Journal Article↗
PubMed1984

The control of firing pattern in nigral dopamine neurons: burst firing.

In addition to firing in a single spiking mode, dopamine (DA) cells have been observed to fire in a bursting pattern with consecutive spikes in a burst displaying progressively decreasing amplitude and increasing duration. In vivo intracellular recording demonstrated the bursts to typically ride on a depolarizing wave (5 to 15 mV amplitude). Although the burst-firing frequency of DA cells showed little correlation with the base line firing rate, increases in firing rate were usually associated with an increase in burst firing. Increases in burst firing could also be elicited by intracellular calcium injection and could be prevented by intracellular injection of EGTA, suggesting a calcium involvement in bursting. Blockade of potassium conductances with extracellular iontophoresis of barium or intracellular injection of tetraethylammonium bromide could also trigger an increased degree of burst firing in DA cells. These data suggest that the increased calcium influx accompanying an increased firing rate triggers burst firing, possibly by inactivating a potassium conductance. A switch from a single spiking mode to a burst-firing mode may be important in modulating striatal DA release, as shown for burst firing in other preparations.

Action Potentials↗
PubMed1998

Phasic firing time locked to cocaine self-infusion and locomotion: dissociable firing patterns of single nucleus accumbens neurons in the rat.

The activity of single nucleus accumbens (NAcc) neurons of rats was extracellularly recorded during intravenous cocaine self-administration sessions (0.7 mg/kg per infusion, fixed ratio 1). We reported previously that NAcc neurons showed a change, usually a decrease, in firing rate during the first 1 min after the cocaine-reinforced lever press. This postpress change was followed by a progressive reversal of that change, which began within the first 2 min after the press and was not complete until the last 1 min before the next lever press (termed the change + progressive reversal firing pattern). In the present study we documented a regular pattern of locomotion that occurred in parallel with the change + progressive reversal firing pattern. This observation suggested that discharges time locked to locomotion may determine the change + progressive reversal firing pattern. However, 55% of the neurons failed to show firing time locked to locomotion that could have contributed to the change + progressive reversal firing pattern. Moreover, for all neurons, the change + progressive reversal firing pattern was apparent even if the calculation of firing rate excluded all periods of locomotion. The present data showed that the change + progressive reversal firing pattern is not solely attributable to phasic changes in firing time locked to the execution of locomotion. The change + progressive reversal firing pattern closely mirrors changes in drug level and dopamine overflow observed by previous researchers and may thus be a component of the neurophysiological mechanism by which drug level regulates drug-taking behavior during an ongoing self-administration session.

Action Potentials↗
PubMed1996

Fire fatality study: demographics of fire victims.

Injury or death caused by fire is frequent and largely preventable. This study was undertaken to define the populations, locations, times and behaviours associated with fatal fires. Seven hundred and twenty-seven fatalities occurring within the State of New Jersey, between the years 1985 and 1991, were examined retrospectively. Most deaths were attributed to a combination of smoke inhalation and burn injury. Five hundred and seventy-four fatalities occurred in residential fires. Smoking materials were the most common source of ignition for residential fires. More than half of the fatal residential fires started between the hours of 11 p.m. and 7 a.m. Children and the elderly represented a disproportionate percentage of fire victims. Victims under the age of 11 years or over the age of 70 years constituted 22.1 per cent of the state population but 39.5 per cent of all fire fatalities. Fire-prevention efforts should target home fire safety, and should concentrate on children and the elderly. The development of fire-safe smoking materials should be encouraged.

Adolescent↗
PubMedDate not supplied

Demographic characteristics, fire experiences, and distress of residential fire survivors.

The United States has one of the highest per capita fire death rates in the world. Death rates alone, however, fail to reflect the breadth of loss experienced by residential fire survivors. Despite the frequency of home fires and the potential for loss, little is known about this vulnerable population. Interviews were conducted with 440 fire survivors 14 weeks after fires. Demographic characteristics of residential fire survivors, survivors' fire experiences, psychological distress after fires and the interrelationships among these variables were examined. This sample of urban fire survivors largely comprised poor, middle-aged African American women. Psychological distress was measured by the General Severity Index of the Brief Symptom Inventory, and the results showed that survivors were highly distressed, even in the absence of fire-related death or physical injury.

Adolescent↗
PubMed1988

Unilateral lesion of the nigrostriatal pathway decreases the firing rate and alters the firing pattern of globus pallidus neurons in the rat.

Activities of spontaneously firing neurons in the globus pallidus of intact rats and rats that survived unilateral lesions of the nigrostriatal pathway for 3 days, 1 week, or 6-11 weeks were compared. No significant differences in neuronal firing rate, firing pattern, and number of cells per pass were observed between chloral hydrate-anesthetized control and lesioned animals. However, in locally anesthetized animals, pallidal cells fired significantly faster than in chloral hydrate-anesthetized animals, and the lesion caused a decrease in the firing rates of pallidal cells 1 week and 6-9 weeks postlesion. In addition, significant differences in the firing pattern of pallidal cells, as determined by the ratio of the mean to median interspike intervals, were seen between locally anesthetized controls and animals surviving 3 days, 1 week, and 6-9 weeks postlesion. This altered firing pattern tended to return to normal with time. The number of cells per pass was not significantly altered by the lesion. Data from this study suggest that, in locally anesthetized animals, the removal of the tonic dopaminergic input to the basal ganglia causes pallidal cells to decrease their firing rates in a time-dependent fashion and causes reversable firing pattern changes. This suggests that tonically active dopamine neurons, probably acting through the striatopallidal pathway, regulate the firing rate and mechanisms controlling the temporal ordering of spontaneous discharges of globus pallidus neurons.

Action Potentials↗
PubMed1996

Application of full-scale fire tests to characterize and improve the aircraft postcrash fire environment.

The Federal Aviation Administration (FAA) has conducted numerous full-scale fire tests for the purpose of characterizing the postcrash cabin fire environment and developing improved fire test criteria for cabin materials. The tests consistently demonstrated the importance of cabin flashover on occupant survivability. Flashover is basically a sudden, very rapid spread of fire, generating large quantities of heat, smoke, and toxic gases that quickly fill the cabin. Before flashover, the cabin environment is largely survivable; after flashover, occupant survival becomes highly unlikely. Thermal incapacitation is more important near the fire origin and at higher elevations, whereas toxic gas incapacitation is predominant away from the fire origin and at lower elevations. The FAA has developed and adopted improved fire test methods for seat cushions (fire blocking layers) and interior panels (low heat release). In both cases, the fire test methods are consistent with full-scale test results and serve to improve occupant survivability by delaying the onset of flashover, thereby providing substantially greater available time for occupant evacuation.

Accidents, Aviation↗
PubMed2003

The three Rs of fire safety, emergency action, and fire prevention planning: promoting safety at the worksite.

Fire safety is of paramount importance for everyone. In many workplaces, the occupational health nurse's scope of practice encompasses safety related activities. Included within this role is the responsibility for fire safety, emergency action, and fire prevention planning. The Three Rs of fire safety, emergency action, and fire prevention plans are rules, responsibilities, and resources. Myriad building and fire safety codes, regulations, and standards exist with which an employer must comply. An employer's responsibility for installing, testing, inspecting, and maintaining fire safety related equipment is extensive. Emergency action and fire prevention planning begins with conducting a detailed physical survey and preparing site maps. It includes making key policy decisions, writing procedures, and training employees in those procedures by practicing and executing site drills. The best resources available for emergency planning are the local fire department and the property insurer. Planning ahead means an efficient emergency response if disaster strikes. It saves lives, limits property damage, and preserves the environment.

Emergencies↗