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PubMed1990

Road to a smoke-free fire service for Florida: policies and progress.

In 1986 the Professional Fire Fighters of Florida (PFFF), a labor organization of 11,000 members, passed an unprecedented resolution to create a "smoke-free fire service." The PFFF's commitment arose from its (i) concern for the health of fire fighters, (ii) need to address the issue of smoking to protect the fire fighters' "Heart and Lung Law," and (iii) attempt to avert criticism of its proposed presumptive "Cancer Bill." In 1987 the PFFF gained support for its resolution from a council representing chiefs, fire instructors and inspectors, and volunteer fire fighters. Prior to the "smoke-free" resolution, one fire department in Florida required that new fire fighters be non-smokers. Since the resolution passed, 14 departments added this requirement. In 1989 the PFFF succeeded in getting a landmark bill passed requiring that new fire fighters be non-users of tobacco for at least one year prior to application. Important implications of the PFFF's efforts to create a "smoke-free fire service" are also discussed.

Fires↗
PubMed1987

Transit time analysis of the forced expiratory spirogram of fire-fighters.

Analysis of the forced expiratory spirogram using time as the primary variable had been shown to be a promising method for detecting small airway dysfunction. This paper describes its application on 277 fire-fighters. Spirometry was performed when the fire-fighters were at rest and had not been fighting fires for the previous 24 hours. The best of three spirograms were used to compute the mean transit time (MTT). Through multiple linear regression analysis, age was the only factor that was significantly associated with MTT. The regression coefficients for age of smoking and non-smoking fire-fighters were nearly equal (0.011 and 0.010 seconds per year respectively). When 28 pairs of smoking and non-smoking fire-fighters were matched for age, duration of service, ethnicity and job groups, their average MTT were not significantly different. An increasing age-adjusted mean MTT was seen among the non-smoking fire-fighters with job groups requiring greater exposure to fire-fighting. Normal smokers had been shown to have a much greater regression coefficient for age on MTT when compared to normal nonsmokers. When compared with this study, the regression equation for MTT of non-smoking fire-fighters differed markedly from that of normal non-smokers and approached that of normal smokers. Coupled with the 'dose-response' relationship shown in the non-smoking fire-fighters, this study provides evidence of pulmonary dysfunction in fire-fighters. This pulmonary dysfunction may be localised in the small airways.

Adult↗
PubMed1996

The epidemiology of aircraft fire in commuter and air taxi crashes.

BACKGROUND: Aircraft fire is recognized as an important risk factor for occupant fatality in aviation crashes, but its epidemiology has not been adequately studied. OBJECTIVE: This study examines factors related to the occurrence of aircraft fire, ignition sources, and factors influencing rescue and firefighting in commuter and air taxi crashes. METHODS: Commuter and air taxi crashes in 1983-88 that involved aircraft fire were analyzed using National Transportation Safety Board (NTSB) data, including NTSB supplemental forms on fire and on rescue and firefighting. RESULTS: Aircraft fire was recorded in 17% of the 888 commuter and air taxi crashes. Factors associated with increased likelihood of fire in these crashes were non-airport location (adjusted relative risk 2.7, 95% confidence interval 1.8-4.1), twin-engine aircraft (RR 2.5, 95% Cl 1.6-3.9), and nighttime (RR 1.7, 95% Cl 1.1-2.5). Fire was more common in Beech 18's than other twin-engine airplanes. The majority (59%) of fires occurred during impact sequence, and an additional 17% occurred after the aircraft came to rest. The engine was identified as the ignition source in 59% of the crashes, followed by hot surface (18%), short circuit (9%), and sparks (9%). Fire sensing and extinguishing systems were installed in only 19% of the aircraft. Rescue and firefighting efforts were hampered most commonly by terrain (48%), weather (47%), and darkness (38%). CONCLUSIONS: Typically induced by impact and started at the engine, aircraft fire is most likely when a crash occurs at night, in a non-airport location, and in instrument meteorological conditions. These high-risk circumstances also often thwart rescue and firefighting efforts.

Accidents, Aviation↗
PubMed2003

Temporal firing characteristics and the strategic role of subicular neurons in short-term memory.

The role of subicular neurons is explored with respect to their participation in short-term memory during performance of a spatial Delayed-Nonmatch-to-Sample (DNMS) task by well-trained rats. Subicular and CA1 neuron firing was examined in the same animals in relation to the encoding of task-relevant events during the DNMS trial. The results indicate that subicular neurons have completely different firing signatures than well-characterized hippocampal neurons in this task. Firing patterns of subicular neurons consisted of five different categories spanning all three phases of the DNMS trial, but concentrated mostly within the Sample and early portion of the Delay period. Unlike hippocampal neurons, subicular cells did not exhibit conjunctive firing correlates with respect to particular combinations of task events; rather, subicular cell firing was differentiated primarily on the basis of temporal specificity within the trial. Only two of the five subicular cell types fired differentially on correct versus error trials; however, one cell type exhibited such differential firing as an inverse function of duration of delay interval. Experiments employing gamma-aminobutyric acid GABA(B) receptor agonists and antagonists showed that both behavioral performance as well as subicular cell firing were disrupted significantly by baclofen at short delays, while performance at long delays and hippocampal cell firing were relatively immune to this effect. The relevance of subicular cell firing in the task with respect to its temporal relation to delay-dependent hippocampal neuronal activity suggests that the structures have complementary roles in the encoding and representation of items in short-term memory.

Action Potentials↗
PubMed1987

Neuroleptic-induced changes in the firing pattern of guinea pig nigrostriatal neurons.

It is well established that neuroleptics increase the firing rate of nigrostriatal neurons. However, the action of these drugs on firing pattern has received scant attention. The effect of local administration of neuroleptic agents was investigated on the firing pattern, and also firing rate, of nigrostriatal neurons. Chlorpromazine or haloperidol was microinjected into the substantia nigra of the urethane-anaesthetized guinea pig during extracellular recordings from identified nigrostriatal cells. Both neuroleptics induced the familiar increase in firing rate of nigrostriatal neurons. More significantly, however, these drugs also caused a dose-dependent change in firing pattern, specific to neuroleptic action. This change consisted of a drug-induced transition from slow irregular single or double spikes with a short interspike interval ('beat' firing) to irregular bursts of spikes with a longer interspike interval ('burst' firing). Furthermore, the transition from beat to burst firing occurred sharply and sometimes continued to switch in a regular cyclical fashion between the two modes for up to three hours following infusion of the neuroleptic. Administration of neuroleptics may thus provide a useful tool for studying the physiology of the firing pattern of nigrostriatal neurons.

Action Potentials↗
PubMed1984

Influence of motor unit firing statistics on the median frequency of the EMG power spectrum.

Changes in the EMG power spectrum during static fatiguing contractions are often attributed to changes in muscle fibre action potential conduction velocity. Mathematical models of the EMG power spectrum, which have been empirically confirmed, predict that under certain conditions a distinct maximum occurs in the low-frequency part of the spectrum, indicating the dominant firing rate of the motor units. The present study investigated the influence of this firing rate peak on the spectral changes during a static fatiguing contraction at 50% of maximum EMG amplitude in the frontalis and corrugator supercilii muscles. An exponential decrease of the median frequency (MF) of the EMG power spectrum was observed when the firing rate peak was absent. When the firing rate peak was present, an exaggerated decrease of MF in the beginning of the contraction was found, which was associated with an increase in firing rate peak magnitude. In later stages of the contraction, a partial recovery of MF occurred, concomitant with a decrease in firing rate peak magnitude. The influence of the firing rate peak on MF was also investigated during nonfatiguing contractions of the frontalis muscle at 20, 40, 60, and 80% of maximum EMG amplitude. A curvilinear relationship between MF and contraction strength was found, whether firing rate peaks were present or absent. The presence of firing rate peaks, however, was associated with a decrease in MF which was inversely related to contraction strength, due to the inverse relationship between firing rate peak magnitude and contraction strength.

Adolescent↗
PubMed1993

Effects of dizocilpine (MK-801) on rat midbrain dopamine cell activity: differential actions on firing pattern related to anatomical localization.

The effects of the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine ((+)-MK-801) on the firing pattern of midbrain dopamine neurons were studied with single cell recording techniques in male albino rats anaesthetized with chloral hydrate. The extracellularly recorded electrical activity of single, identified dopamine neurons was studied with respect to firing rate, burst firing and regularity of firing. MK-801 (0.01-1.0 mg/kg IV) induced different effects in different subgroups of midbrain dopamine neurons. In the substantia nigra, firing rate was increased while the pattern was regularized and burst firing slightly increased. In the ventral tegmental area, firing rate and regularity of firing was also increased while effects on burst firing were bidirectional. Histological inspections revealed that neurons which responded with an increase in burst firing were mainly located in the nucleus paranigralis subdivision of the ventral tegmental area, while cells responding with a decrease were predominantly found in the nucleus parabrachialis pigmentosus subdivision. The effects of MK-801 were similar to previously described effects of phencyclidine, another non-competitive NMDA antagonist. The present effects of MK-801 might shed some light on the mechanisms involved in psychotic symptoms induced by phencyclidine and other non-competitive NMDA antagonists.

Action Potentials↗
PubMed1999

Relation between torque history, firing frequency, decruitment levels and force balance in two flexors of the elbow.

By means of intramuscular electromyographic recordings, we studied the firing frequencies and recruitment/decruitment thresholds of individual motor units in two elbow flexors, the biarticular biceps brachii muscle and the monoarticular brachioradialis muscle. Subjects had to perform isometric contractions with increasing elbow flexion torque until a specific peak torque level was reached. The torque level was kept constant for 6 s during which firing frequencies were measured. Then the torque was decreased to a lower level and, after 3 s, firing frequencies were again measured for 6 s. By repeating this procedure, the torque level was decreased stepwise until the motor unit under study stopped firing. The last level before the unit stopped firing was considered to be the decruitment torque level. We measured the firing frequency at recruitment and decruitment, the torque-frequency relationship and the recruitment and decruitment torque thresholds after various levels of peak torque. In the biceps, both the firing frequencies at a specific torque level and the decruitment torque level itself were independent of the peak torque. In the brachioradialis, however, firing frequencies at a specific torque level decreased and decruitment torque levels increased after subjects generated higher peak torques. Thus, in this muscle firing frequencies as well as decruitment thresholds show hysteresis effects. The result indicates a shift of force from the brachioradialis muscle during recruitment to the biceps muscle during decruitment. This shift is smaller than was concluded from previous studies in which decruitment threshold levels for the brachioradialis muscle were assumed to be independent of force history. Moreover, we found that in both muscles decruitment firing frequencies were lower than recruitment frequencies and they were independent of the peak torque level. In order to analyse the effect of the peak torque level on the distribution of force over the two muscles, we performed a model study in which we simulated the activation-frequency relation of two elbow flexors: a biceps-like and brachioradialis-like muscle, each contributing equally to the elbow torque during recruitment. In addition, we analysed how the different behaviour of the biceps and the brachioradialis during decruitment alters their contribution to the total torque production and how this redistribution is caused. The model study shows that the shift in contribution to the total torque is not constant during the relaxation phase and is not caused by a simple mechanism like a shift of activation from one muscle to another. Furthermore, changes limited to the muscle in which hysteresis is present do not seem to be sufficient to explain the experimental results.

Action Potentials↗
PubMed1992

Concentrations of carbachol stimulating phosphoinositide hydrolysis cause a sustained decrease in membrane potential and firing rate: role of inositol and inositol polyphosphate second messengers.

We have investigated the relationship between muscarinic agonist-stimulated phosphoinositide (PI) hydrolysis and electrophysiological responses in rat hippocampal slice preparations. In a previous extracellular study, we found that muscarinic agonists at concentrations that stimulate PI hydrolysis result in a biphasic firing response; an initial increase in firing followed by loss of firing at higher concentrations. To test the hypothesis that variability in obtaining consistent loss of firing is related to depletion of intracellular inositol, we investigated the effects of adding exogenous inositol to the buffer. We now report that concentrations of inositol similar to those in cerebral spinal fluid (30-100 microM) augment carbamylcholine (carbachol, CCh) mediated loss of firing and [3H]inositol-1,3,4,5-tetrakisphosphate ([3H]Ins(1,3,4,5)P4) formation. Inhibition of firing produced by 30 microM CCh in the presence of inositol was associated with a sustained depolarization of 20-25 mV, an increased slope resistance in the depolarized range (-60 to -40 mV), and a parallel shift in the hyperpolarized (-100 to -70 mV) range of the voltage-current curve and increased frequency of spontaneous IPSPs. Under voltage-clamp, measurements of the M-current (IM) showed sustained inactivation by CCh with reversal after washout of CCh. Manual depolarization of cells by current injection to the same level of depolarization as attained with CCh did not usually lead to the same loss of firing. These findings suggest that IM, and possibly other voltage-independent currents or ion pumps, may cause loss of firing only in part through a depolarization blockade of firing and not through desensitization. Furthermore, CCh treatment without inositol did not depolarize neurons as much as CCh with inositol, and usually did not cause a delayed loss of firing. Brain slice preparations may thus require physiological concentrations of inositol to show consistent or maximum phosphoinositide-mediated electrophysiological responses.

Action Potentials↗
PubMed1988

Allergens in Hymenoptera venom. XXI. Cross-reactivity and multiple reactivity between fire ant venom and bee and wasp venoms.

The relationships between fire ant venom and bee and wasp venoms were explored by studying sera from five groups of subjects. Group 1 included adults not allergic to any venoms and who were not exposed to fire ants. Group 2 included adults with fire ant exposure who were not allergic to venoms. Group 3 included patients with recent systemic reactions to fire ant venom. Group 4 included patients allergic to bee and vespid venoms with no fire ant exposure. Last, group 5 included patients allergic to bee and vespid venoms with fire ant exposure. None of the serum samples from group 1 was RAST reactive to fire ant venom, but 24% of those from group 2 were fire ant positive, as were 100% of those from group 3, 51% of those from group 4, and 87% of those from group 5. The RAST-positive patients in groups 2 and 5 were also skin test positive. RAST inhibition studies demonstrated cross-reactivity in some cases and multiple reactivity in others. The serum samples were further investigated via nondenaturing electrophoretic immunoblot studies and RAST with highly purified allergens. Serum samples from group 4 reacted to a single band on immunoblots and with only one of the four purified allergens from fire ant venom (Solenopsis invicta I, or Sol i I). Serum samples from groups 2, 3, and 5 showed various patterns of allergen reactivity. All serum samples from patients allergic to fire ant venom who also reacted to bee and/or vespid venoms by RAST contained IgE antibodies binding to Sol i I.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Regular firing patterns of suprachiasmatic neurons maintained in vitro.

Cells of the suprachiasmatic nucleus (SCN) recorded in vitro display a characteristic firing pattern. Unlike many other central neurons, they have the ability to fire at a constant low rate with fixed interspike interval. This regularity is most pronounced at firing rates above 3-5 spikes/s. Spontaneous firing below 3 spikes/s was less regular but became increasingly regular as the firing rate was increased. Similarly, regular discharges became irregular when the firing rate was reduced below 3-5 spikes/s. The mean spontaneous firing rate was 5.6 +/- 1.6, range less than 1 to 12 spikes/s and cells were resistant to attempts to increase their rate of firing beyond 15-20 spikes/s. Statistical analysis showed that the firing patterns of all the cells studied formed a single continuous population in terms of their interspike interval distributions, and that these distributions were a function of the firing rate. Addition of either of two commonly used anesthetics, urethane or sodium pentabarbitone, disrupted previously stable, regular activity.

Action Potentials↗
PubMed1995

Evidence for a repetitive (burst) firing pattern in a sub-population of 5-hydroxytryptamine neurons in the dorsal and median raphe nuclei of the rat.

Previous electrophysiological studies have shown that spontaneously active mesencephalic 5-hydroxytryptaminergic neurons of anaesthetized or freely moving animals fire solitary spikes in a slow, regular pattern. In the present study, using extracellular single unit recordings from dorsal and median raphe neurons of the anaesthetized rat, an additional electrophysiological property of a sub-population of presumed 5-hydroxytryptaminergic neurons was observed. These neurons, during their otherwise regular firing pattern, repeatedly fired two (or occasionally three or even four) spikes where only one was expected. Spikes in this burst-like repetitive firing mode (spikes in doublets or triplets) occurred in a short time interval (range: 2.4-11.5 ms), and with a diminishing spike amplitude. Cross-correlation analysis of spikes in doublets revealed a very high interdependency between them. The proportion of spikes in doublets to solitary spikes showed great variation between different neurons, ranging from 5 to 95% of the total spikes displayed. However, for each neuron the proportion of spikes in doublets to solitary spikes, and the time interval between the spikes in doublets, remained constant during control recordings. All these features are characteristic of single neurons firing in a repetitive firing pattern rather than simultaneous recordings of two separate 5-hydroxytryptaminergic neurons. Repetitive firing neurons were recorded with a similar frequency in both chloral hydrate and Saffan anaesthetized rats, and were detected using both glass and metal electrodes. Furthermore, neurons with a repetitive firing pattern were inhibited by intravenous administration of a selective 5-hydroxytryptamine1A receptor agonist and a 5-hydroxytryptamine reuptake inhibitor, thus displaying responses typical of 5-hydroxytryptaminergic neurons. Repetitive firing neurons occurred in both the dorsal and median raphe nuclei, although they were much more frequent in the dorsal raphe nucleus (91 of 332 neurons). The occurrence of repetitive firing neurons in the midbrain raphe nuclei is a newly described phenomenon which may indicate unique properties of a sub-population of 5-hydroxytryptaminergic neurons. In functional terms, it could modify both axonal and dendritic 5-hydroxytryptamine release, and provide an additional option for neuronal information signalling.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed2006

Cortical network modeling: analytical methods for firing rates and some properties of networks of LIF neurons.

The circuitry of cortical networks involves interacting populations of excitatory (E) and inhibitory (I) neurons whose relationships are now known to a large extent. Inputs to E- and I-cells may have their origins in remote or local cortical areas. We consider a rudimentary model involving E- and I-cells. One of our goals is to test an analytic approach to finding firing rates in neural networks without using a diffusion approximation and to this end we consider in detail networks of excitatory neurons with leaky integrate-and-fire (LIF) dynamics. A simple measure of synchronization, denoted by S(q), where q is between 0 and 100 is introduced. Fully connected E-networks have a large tendency to become dominated by synchronously firing groups of cells, except when inputs are relatively weak. We observed random or asynchronous firing in such networks with diverse sets of parameter values. When such firing patterns were found, the analytical approach was often able to accurately predict average neuronal firing rates. We also considered several properties of E-E networks, distinguishing several kinds of firing pattern. Included were those with silences before or after periods of intense activity or with periodic synchronization. We investigated the occurrence of synchronized firing with respect to changes in the internal excitatory postsynaptic potential (EPSP) magnitude in a network of 100 neurons with fixed values of the remaining parameters. When the internal EPSP size was less than a certain value, synchronization was absent. The amount of synchronization then increased slowly as the EPSP amplitude increased until at a particular EPSP size the amount of synchronization abruptly increased, with S(5) attaining the maximum value of 100%. We also found network frequency transfer characteristics for various network sizes and found a linear dependence of firing frequency over wide ranges of the external afferent frequency, with non-linear effects at lower input frequencies. The theory may also be applied to sparsely connected networks, whose firing behaviour was found to change abruptly as the probability of a connection passed through a critical value. The analytical method was also found to be useful for a feed-forward excitatory network and a network of excitatory and inhibitory neurons.

Action Potentials↗
PubMed2004

Pallidal control of substantia nigra dopaminergic neuron firing pattern and its relation to extracellular neostriatal dopamine levels.

The firing patterns of dopaminergic neurons in vivo are strongly modulated by afferent input. The principal GABAergic inputs to the dopaminergic neurons of the substantia nigra originate from neurons of the neostriatum, globus pallidus and substantia nigra pars reticulata. It has previously been shown that the firing pattern of nigral dopaminergic neurons can be manipulated by pharmacologically induced excitation or inhibition of the globus pallidus with relatively little effect on firing rate. We used this technique to explore the relation between the firing pattern of dopaminergic neurons and extracellular dopamine levels in the neostriatum in vivo. Specifically, we tested whether an increase in burst firing in dopaminergic neurons produced by increased pallidal activity led to increased extracellular dopamine levels in the neostriatum. Single unit extracellular recording combined with simultaneous microdialysis was used to measure the firing rates and patterns of dopaminergic neurons and extracellular striatal dopamine levels, respectively, during bicuculline-induced excitation of the globus pallidus. Pallidal excitation resulted in a marked increase in burst firing in dopaminergic neurons along with only a slight increase in firing rate, but produced a significant elevation (approximately 45%) in neostriatal dopamine levels. These data suggest that afferent-induced burst firing in dopaminergic neurons leads to an increase in extracellular dopamine levels in the neostriatum when compared with less bursty patterns with similar overall firing rates.

Animals↗
PubMed2006

Maturation of firing pattern in chick vestibular nucleus neurons.

The principal cells of the chick tangential nucleus are vestibular nucleus neurons participating in the vestibuloocular and vestibulocollic reflexes. In birds and mammals, spontaneous and stimulus-evoked firing of action potentials is essential for vestibular nucleus neurons to generate mature vestibular reflex activity. The emergence of spike-firing pattern and the underlying ion channels were studied in morphologically-identified principal cells using whole-cell patch-clamp recordings from brain slices of late-term embryos (embryonic day 16) and hatchling chickens (hatching day 1 and hatching day 5). Spontaneous spike activity emerged around the perinatal period, since at embryonic day 16 none of the principal cells generated spontaneous action potentials. However, at hatching day 1, 50% of the cells fired spontaneously (range, 3 to 32 spikes/s), which depended on synaptic transmission in most cells. By hatching day 5, 80% of the principal cells could fire action potentials spontaneously (range, 5 to 80 spikes/s), and this activity was independent of synaptic transmission and showed faster kinetics than at hatching day 1. Repetitive firing in response to depolarizing pulses appeared in the principal cells starting around embryonic day 16, when <20% of the neurons fired repetitively. However, almost 90% of the principal cells exhibited repetitive firing on depolarization at hatching day 1, and 100% by hatching day 5. From embryonic day 16 to hatching day 5, the gain for evoked spike firing increased almost 10-fold. At hatching day 5, a persistent sodium channel was essential for the generation of spontaneous spike activity, while a small conductance, calcium-dependent potassium current modulated both the spontaneous and evoked spike firing activity. Altogether, these in vitro studies showed that during the perinatal period, the principal cells switched from displaying no spontaneous spike activity at resting membrane potential and generating one spike on depolarization to the tonic firing of spontaneous and evoked action potentials.

2-Amino-5-phosphonovalerate↗
PubMed2000

Improving the processing of high-gold metal-ceramic frameworks by a pre-firing heat treatment.

OBJECTIVES: High-gold metal-ceramic alloys are difficult to elaborate due to their soft surface. Overlappings after grinding cause porosities at the metal-ceramic interface. Poor mechanical strength at high temperatures leads to thermal distortion of the framework. During firing hardness and high temperature strength of the alloy improve, thus improving processing. Therefore the question arises if by a pre-firing heat treatment hardening can be anticipated without affecting the mechanical strength after firing. METHODS: Four commercially available alloys were investigated with regard to hardness, thermal distortion, proof stress, and grain growth in the as-cast state, after a pre-firing heat treatment at 950 degrees C for 10 min, after a complete firing cycle and after a combination of both heat treatments. Hardness was measured as HV5/30, thermal distortion by means of a three point bending test and proof stress according to ISO 9693: 1991. The results were compared by means of Student's t-test (p < 0.05). RESULTS: For all alloys hardness, resistance to thermal distortion, and proof stress significantly increased after the pre-firing heat treatment compared to the as-cast state. When a pre-firing heat treatment was performed before the complete firing cycle, hardness may slightly drop, but proof stress and resistance to thermal distortion remained at least constant or even improved, compared to the results obtained after a complete firing cycle. Grain growth due to the pre-firing heat treatment was not observed. SIGNIFICANCE: The results showed, that a heat treatment of high-gold frameworks performed directly after casting improves processing without affecting mechanical strength.

Ceramics↗
PubMed2005

Personal protection measures against fire ant attacks.

BACKGROUND: Fire ant stings lead to significant morbidity and mortality each year. Virtually no information exists in the scientific literature about the effectiveness of personal protection measures against these ants. OBJECTIVES: To quantify the level of protection from ant stings by socks and cotton tights and to evaluate the efficacy of repellents and other chemicals in preventing stings. METHODS: Commercially obtained infant socks were fitted on a plastic doll's foot, which was touched to fire ant mounds in a series of controlled experiments. Socks and cotton tights were stretched over a human finger and placed in a fire ant mound to test the ability of ants to sting through fabric. Assays were developed to screen chemical substances for their ability to stop or prevent fire ant stings. RESULTS: Socks of any type reduced the number of fire ants that reached the skin and delayed the time required for ants to reach the skin above the sock level. Fire ants were unable to sting through all socks tested. Ants successfully stung both paper towels and human skin, regardless of chemical substance or repellent applied to them. CONCLUSIONS: Socks provide some degree of protection from fire ant stings; therefore, children living in fire ant-infested areas should wear them. Fire ants appear unable to sting through many commercially available socks. Cotton tights may be useful in protecting the lower extremities of children. Fire ants are not deterred from stinging by a wide variety of insect repellents and chemical substances.

Animals↗
PubMed1996

Hypersensitivity to fire ant venom.

LEARNING OBJECTIVES: Reading this article will reinforce the reader's knowledge of the taxonomy, origin, and distribution of fire ants and will increase his ability to diagnose and manage reactions caused by the two imported species, Solenopsis invicta and richteri. This review will also enhance the reader's knowledge of the available diagnostic methods and therapeutic measures, including the role of fire ant venom versus whole body extract in the management of fire ant allergy. DATA SOURCES: Information for this review was obtained primarily from abstracts and articles written by investigators recognized for their expertise in fire ant venom research. STUDY SELECTION: References were selected based on their clinical applicability and relevance to the epidemiology and pathophysiology of imported fire ant hypersensitivity. CONCLUSIONS: The imported fire ant represents a significant health hazard for persons living in fire ant endemic areas in the southern United States. Sting reactions range from local pustules and large, late-phase responses to life-threatening anaphylaxis. Fire ant allergen-specific immunotherapy can reduce the risk of subsequent systemic reactions. Four important Sol i venom allergens have been isolated and characterized. Clinical studies have been designed to compare the safety and efficacy of fire ant venom with whole body extract for diagnosis and treatment of fire ant allergy.

Animals↗