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At least 19 recordsLinked to original sources
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↗
PubMed1989

Motor unit firing rates and firing rate variability in the detection of neuromuscular disorders.

We have used automatic decomposition electromyography (ADEMG) to study 41 muscles in 29 patients with well-defined peripheral and central motor disorders. In motor neuron diseases motor unit action potentials (MUAPs) showed increased amplitudes, firing rates and firing variability. Relatively large MUAPs sometimes were not identified by the computer program if they lacked sufficient high-frequency signal content, or were too variable in shape. In myopathies the MUAPs showed reduced amplitudes, durations and turns, and sometimes dramatic increases in firing rates. Also, the mean number of MUAPs per recording site was often increased, indicating excessive recruitment. In polymyositis (the best studied myopathy) the nature and magnitude of the MUAP shape and firing abnormalities were usually similar at different levels of contractile force, suggesting that motor units are affected without regard to recruitment order. In upper motor neuron paresis (multiple sclerosis), the shape properties of the MUAPs were normal, but mean firing rates were reduced, and firing variability increased. These findings confirm many of the traditional criteria for distinguishing neurogenic from myopathic disease electrophysiologically at the level of the individual MUAP. In addition, they demonstrate the potential diagnostic sensitivity of MUAP firing rate measurements for detecting neuromuscular dysfunction, and for differentiating between some cases of central and peripheral paresis, but not for distinguishing peripheral neurogenic from myopathic weakness, since firing rates tend to increase in both. Increased firing rate variability may be a marker of central or peripheral neurogenic weakness.

Action Potentials↗
PubMed1977

The spontaneous firing patterns of forebrain neurons. III. Prevention of induced asymmetries in caudate neuronal firing rates by unilateral thalamic lesions.

Unilateral lesions interrupting striatal outputs and inputs (MFB lesions) produce a marked slowing of neuronal firing in the caudate nucleus contralateral to the side of the lesions without affecting neuronal firing in the ipsilateral caudate nucleus. Although the MFB lesion also interrupts the nigrostriatal pathway and depletes the ipsilateral striatum of dipamine and its associated enzymes, the slowing of unit firing rates is apparently due to interruption of striatal outputs rather than inputs. Unilateral thalamic lesions palced ipsilateral to MFB lesions in iether the ventral anterior-ventrolateral nuclei (VA-VL) or in the center median-parafascicular nuclei (CM-PF) prevent the MFB lesion-induced asymmetry in caudate neuronal firing rates. These thalamic lesions do not, however, restore the striatal dopamine content depleted by the MFB lesion. Unilateral CM-PF lesions in otherwise intact cats do not alter caudate unit firing rates nor do they affect striatal dopamine. VA-VL lesions in otherwise intact cats produce a bilateral slowing in the spontaneous firing of neurons in the caudate nuclei, again, whithout altering caudate dopamine concentrations. These results provide further evidence that caudate dopamine concentration per se does not appear to be a potent variable in controlling the spontaneous firing rates of striatal neurons.

Animals↗
PubMed1976

Imported fire ant hypersensitivity. Studies of human reactions to fire ant venom.

It is now apparent that venom and venom components of the Hymenoptera superfamilies of Apida (honeybee) and Vespida (wasps, yellow jackets, and hornets) are becoming increasingly important in the diagnosis and treatment of hypersensitivity reactions. Stings from fire ants (superfamily Formicidae, family Myrmicinae) have also been recognized as causes of systemic reactions in man. Fire ant venom is unique in its composition, consisting mainly of alkaloids in aqueous suspension with only trace amounts of protein. This study compares the skin reactivity of fire ant venom and synthesized alkaloid components with the whole body extract (WBE) of fire ants and other Hymenoptera. The venom as well as the WBE of fire ants was found useful for skin test diagnosis of sensitive individuals. There appear to be cross-reactive or shared antigens between fire ant venom, WBE, and WBE of other Hymenoptera. Successful passive transfer of skin reactivity to nonsensitive individuals was accomplished with sera from sensitive individuals. Loss of this passive transfer by heating sera at 56 degrees C for 4 hr is evidence in favor of IgE mediating the positive skin test to the venom.

Animals↗
PubMed1992

Safety and efficacy of fire ant venom in the diagnosis of fire ant allergy.

Thirty-three adult patients who had had systemic allergic reactions to fire ant stings and 33 insect-nonallergic control subjects were skin tested with single lots of Solenopsis invicta (Sol i) fire ant venom (IFAV) and two commercially available imported fire ant whole body extracts (IFA WBEs). All three extracts were analyzed for protein concentration. Sol i II and Sol i III concentrations were each assayed by means of two ELISAs with complementary monoclonal antibodies, one species specific and one cross-reactive. Radioallergosorbent test (RAST) to IFAV and both IFA WBEs was performed on sera from all study subjects. Both IFA WBEs contained high concentrations of fire ant body proteins. Sol i II and III concentrations each varied twofold between the two IFA WBE preparations. Patients were generally more reactive to IFAV than IFA WBE by skin testing and RAST. IFAV RAST appeared to be a more sensitive assay than IFA WBE RAST. No adverse reactions occurred to skin testing with IFAV, but intradermal testing with higher concentrations of IFA WBE caused delayed large local reactions in 16 of 30 (53%) control subjects. These reactions were attributed to the large amounts of extraneous body proteins in IFA WBE. These results (1) demonstrate that skin testing with IFAV is safe, (2) indicate that IFAV is more potent than IFA WBE, and (3) suggest that IFAV may be the superior reagent for diagnosis of fire ant allergy.

Adult↗
PubMed1977

Carboxyhemoglobin concentrations in flash fire victims: report of six simultaneous fire fatalities without elevated carboxyhemoglobin.

Eight people died in a traffic accident involving a tractor-trailer and ten autos. The accident caused a series of flash fires from ruptured gas tanks. Complete autopsies established that six of the victims died exclusively from thermal trauma; none showed an elevated blood carboxyhemoglobin concentration. Flash fire victims are exceptions to the axiom that elevation of blood carboxyhemoglobin is a sine qua non for concluding that a decedent recovered from the scene of a conflagration was alive in the fire.

Accidents, Traffic↗
PubMed1979

Fire deaths and drinking: data from the Ontario fire reporting system.

Data on recorded alcohol impairment of 264 victims of fatal fires in Ontario in 1976 are analyzed. Male victims were twice as likely to be impaired as females, and impairment was more common among those under 50 years of age. Alcohol impairment was most often noted in victims of fires at night and on weekends. Overall, 31% of adult victims were reported as alcohol impaired. The Ontario data suggests alcohol involvement in victims was not associated with smoking as a cause of the fire.

Alcohol Drinking↗
PubMed1987

Neuronal firing in the pallidal region: firing patterns during sleep-wakefulness cycle in cats.

Neuronal activity was investigated by extracellular microelectrodes in the pallidal region of freely moving cats during wakefulness (W), slow-wave sleep (SWS) and paradoxical sleep (PS). The firing of 150 units from 35 points was examined. On the basis of the modifications of firing rates and patterns during the sleep-wakefulness cycle, 5 groups of neurons were distinguished. Two of these groups were characterized by strong increase of firing rate in W and PS and in one of them this increase preceded the cortical activation at the SWS-PS transition by an average of 26 sec. The role played by the basal forebrain area in the regulation of the sleep-wakefulness cycle is discussed.

Action Potentials↗
PubMed1989

Survey of fatal anaphylactic reactions to imported fire ant stings. Report of the Fire Ant Subcommittee of the American Academy of Allergy and Immunology.

A physician questionnaire survey was conducted by the Fire Ant Subcommittee of the American Academy of Allergy and Immunology to document deaths caused by imported fire ant stings. From the 29,300 physicians surveyed, reports of 83 fatal and two near-fatal fire ant-sting reactions were received. Most anaphylactic deaths were reported from Florida (22) and Texas (19). After excluding duplicate reports, four confirmed deaths were documented in Alabama, 10 in Florida, two in Georgia, two in Louisiana, and 14 in Texas.

Adult↗
PubMed1979

The spontaneous firing patterns of forebrain neurons. IV. Effects of bilateral and unilateral frontal cortical ablations on firing of caudate, globus pallidus and thalamic neurons.

To assess the effects of partial deafferentation of the neostriatum on spontaneous neuronal activity in the basal ganglia and related thalamic nuclei, ablations of frontal cortex were carried out in adult cats. Postoperative measures of interspike intervals of single neurons in the caudate nucleus, globus pallidus and ventral anterior-ventral lateral complex of the thalamus revealed a slowing of neuronal firing in these structures as compared with non-lesioned controls. The fact that deafferentation by cortical damage produces changes in neuronal firing in target neurons of the striatum (globus pallidus) and in thalamic neurons at least two synapses removed from the striatum is noteworthy. The possible extent to which these results might have been influenced by reduction of cortical inputs to or denervation of the thalamus is discussed.

Afferent Pathways↗
PubMed1990

[Reactions at the nonprecious metal-ceramic interface during porcelain firing. (3) A commercial alloy forming much Cr oxide during firing].

To examine the interface reaction between porcelain and a commercial Ni-Cr dental alloy (containing higher Cr and Mo) during porcelain firing, electron probe microanalyzer (EPMA) and X-ray diffraction have been used to characterize the interface which has emerged by means of selective dissolution of the alloy caused by a bromine-methanol solution. Much Cr oxide was formed at the early stage of firing, and remained in the reaction layer even if the holding time at 960 degrees C was up to 8 minutes. As a result, many Cr atoms diffused into the porcelain layer, most of which was found to form oxides through X-ray diffraction. Moreover, the porcelain layer nearest to the oxide layer was deduced to be modified seriously.

Chromium↗
PubMed1978

Hippocampal place units in the freely moving rat: why they fire where they fire.

Place units in the dorsal hippocampus of the freely-moving rat signal the animal's position in an environment (place field). In the present experiments, thirty four place units were recorded in two different environments: one, a small platform where the rat had received neither training nor reward; the other, an elevated T-maze inside a set of black curtains where the rat had been trained on a place discrimination. The places within the curtained enclosure were specified by four cues (a light, a card, a fan, and a buzzer) in addition to the food. Other cues were eliminated by rotating the maze and the four controlled cues relative to the external world from trial-to-trial. Some units had place fields in both environments while others only had a place field in one. No relationship could be seen between the place fields of units with fields in both environments. All twelve units tested extensively in the controlled enclosure had place fields related to the controlled cues. Probe experiments in which only some of the controlled cues were available showed that some of these units were being excited by one or two cues while others were influenced in a more complex way. The fields of these latter units were maintained by any two of the 4 cues and were due to inhibitory influences which suppressed the unit firing over the rest of the maze.

Acoustic Stimulation↗
PubMed1989

Survey of whole body-extract immunotherapy for imported fire ant- and other hymenoptera-sting allergy. Report of the Fire Ant Subcommittee of the American Academy of Allergy and Immunology.

A survey of 5300 allergists was conducted to determine the number and geographic distribution of patients receiving immunotherapy for imported fire ant (IFA) allergy in the United States and Canada. Responses were received from 1293 physicians who reported a total of 2573 patients being treated in 28 states. Most patients were from the southeast, but some patients were reported to be receiving IFA immunotherapy in areas outside the boundaries of known IFA infestation. Although IFA is a widespread health hazard in the southeast, it appears to exert an uneven impact on allergy practice in this region. Of the 1293 physicians responding to the survey, 117 (9%) reported the use of whole body extract (WBE) in the treatment of 1746 patients with winged Hymenoptera-sting allergy. Continued use of WBE immunotherapy was reported by physicians from all regions of the United States and from Canada. The largest numbers of patients receiving winged WBE immunotherapy were reported from Texas (641), Pennsylvania (246), Florida (129), and Canada (127). The results of this survey suggest a need for continuing medical education regarding (1) the magnitude of the health hazard posed by the IFA and (2) the efficacy of venom versus WBE in the treatment of winged Hymenoptera-sting allergy.

Animals↗
PubMed1979

[Psychophysiology of fire walking. II. Pain perception in pyrovasy (fire walking)].

Our paper is concerned with considerations of pain physiology in pyrovasy and with neuropharmacological effects of the Opiate antagonist Naloxone. These considerations explain the relationship of analgesia and hypersthesia with stress induced behavior and states of consciousness. Apart from psychophysiological aspects we can distinguish from a biochemical and neurophysiological point of view two mechanisms of pain perception in pyrovates: 1. Certain mechanical stimuli brought about by the individual running technique of the pyrovate cause convergence of noxis and non-noxic afferent impulses as well as central inhibition of the effect of noxic stimuli. 2. The long stressful period of preparations induces a temporary surplus of Endorphins elevating the pain threshold.

Adult↗