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Biomedical subjects

A Axelsson

Publications and source records attributed to A Axelsson.

At least 19 recordsLinked to original sources
PubMed1995

Survival among patients with out-of-hospital cardiac arrest found in electromechanical dissociation.

BACKGROUND: Many patients who suffer an out-of-hospital cardiac arrest are found in electromechanical dissociation at the time the Emergency Medical Service (EMS) arrives. Since they have a poor prognosis, less attention has been paid to them. AIM: To describe a consecutive population of patients with out-of-hospital cardiac arrest found in electromechanical dissociation and to try to define indicators for an increased chance of survival in this patient population. SETTING: The municipality of Göteborg. PATIENTS: All the patients who suffered an out-of-hospital cardiac arrest between 1981-1992 and were reached by our EMS system and in whom cardiopulmonary resuscitation (CPR) was attempted. RESULTS: In all, there were 3434 patients with cardiac arrest of whom 748 (22%) were found in electromechanical dissociation. They differed from patients found in ventricular fibrillation as there were more women, a higher frequency of cardiac arrest during the night, a lower frequency of witnessed cardiac arrest and consequently a lower frequency of bystander-initiated CPR. In all, 96 patients (13%) were hospitalized alive and only 16(2%) could be discharged from hospital. In a multivariate analysis relating to age, sex, time of cardiac arrest, interval between collapse and the arrival of the first ambulance, bystander-initiated CPR and treatment with adrenaline, atropine and tribonate, no independent predictor of survival was found. CONCLUSION: Of all the patients with out-of hospital cardiac arrest in whom CPR was attempted by our EMS, 22% were found in electromechanical dissociation. Of these, 13% were hospitalized alive and 2% could be discharged from the hospital. No independent predictor of an increased chance of survival was found.

Adolescent↗
PubMed1995

Adrenaline in out-of-hospital ventricular fibrillation. Does it make any difference?

BACKGROUND: A large proportion of cardiac arrests outside hospital are caused by ventricular fibrillation. Although it is frequently used, the exact role of treatment with adrenaline in these patients remains to be determined. AIM: To describe the proportion of patients with witnessed out-of-hospital cardiac arrest found in ventricular fibrillation who survived and were discharged from hospital in relation to whether they were treated with adrenaline prior to hospital admission. PATIENTS AND TREATMENT: All the patients with out-of-hospital cardiac arrest found in ventricular fibrillation in Göteborg between 1981 and 1992 in whom cardiopulmonary resuscitation (CPR) was initiated by our emergency medical service (EMS). During the observation period, some of the EMS staff were authorized to give medication and some were not. RESULTS: In all, 1360 patients were found in ventricular fibrillation and detailed information was available in 1203 cases (88%). Adrenaline was given in 417 cases (35%). Among patients with sustained ventricular fibrillation, those who received adrenaline experienced the return of spontaneous circulation more frequently (P < 0.001) and were hospitalized alive more frequently (P < 0.01). However, the rate of discharge from hospital did not differ significantly between the 2 groups. Among patients who converted to asystole or electromechanical dissociation, those who received adrenaline experienced the return of spontaneous circulation more frequently (P < 0.001) and were hospitalised alive more frequently (P < 0.001). However, the rate of discharge from hospital did not differ significantly between the 2 groups. CONCLUSIONS: On the basis of 2 treatment regimens during a 12-year survey, we explored the usefulness of adrenaline in out-of-hospital ventricular fibrillation. Both patients with sustained ventricular fibrillation and those who converted to asystole or electromechanical dissociation had an initially more favourable outcome if treated with adrenaline. However, the final outcome was not significantly affected. This study does not confirm the hypothesis that adrenaline increases survival among patients with out-of-hospital cardiac arrest who are found in ventricular fibrillation.

Aged↗
PubMed1995

Hearing in pop/rock musicians: a follow-up study.

In 1975, the threshold hearing levels (HLs) of 83 Swedish and British pop/rock musicians were examined with pure tone audiometry. At that time we found 13% of the musicians with a hearing loss > 20 dB HL at a high frequency pure tone average (3, 4, 6, and 8 kHz). The aim of the present investigation was to conduct an audiometric follow-up study of these musicians 16 years after the first examination. Fifty-three of the 83 pop/rock musicians were retested in 1991 to 1992. They also filled in a questionnaire concerning occupational noise activities, leisure noise activities, general health problems and subjective symptoms related to loud music exposure. The median pure tone audiogram was within 20 dB HL at all test frequencies. On an individual basis, 63% had normal high high frequency pure tone average scores and another 15% had a very limited high frequency hearing loss (< or = 25 dB HL). It seems surprising that pop/rock musicians after performing for 26 years have such well-preserved hearing. There might be a protective effect by the generally positive attitude from the musicians toward their performance and their audience. Regarding the loud and more or less continuous sound levels over 85 dBA there might also be a protective effect from a continuous contraction of the stapedius muscle.

Acoustic Stimulation↗
PubMed1995

Auditory brainstem response latencies in patients with tinnitus.

Two groups of patients with annoying tinnitus were studied with brainstem response audiometry. One group comprised 56 patients with normal hearing or slight hearing loss and another of 57 patients with moderate to pronounced sensorineural hearing loss. The patients were compared with 220 controls matched regarding gender, age, and hearing loss. Two patterns of abnormalities were found. One is a prolongation of wave I accompanied by a prolongation of waves III and V, findings which are consistent with a lesion in the peripheral auditory system. The other is a lengthening of the III-V IPL, indicating a dysfunction in the brainstem. Both patterns occurred most often in tinnitus patients with normal hearing or slight hearing loss.

Adult↗
PubMed1992

Effect of low level acoustic stimulation on temporary threshold shift in young humans.

To assess the effect of a low level acoustic stimulation on the susceptibility to noise, young human subjects were exposed to music at 70 dBA for 6 h per day during 9 days (training period). Noise sensitivity was assessed by measuring temporary threshold shift (TTS) induced by 105 dBSPL, 1/3 octave band noise at 2 kHz for 10 min. On the fifth day of the training period, a significant decrease of TTS was observed in the frequency range 3-3.5 kHz, in comparison with the baseline TTS obtained before being trained. As the training continued, the frequency range which showed a significant reduction of TTS expanded to 2-5 kHz.

Acoustic Stimulation↗
PubMed1992

The development of melanin in the stria vascularis of the gerbil.

One factor that influences noise susceptibility is pigmentation. The aim of this study was to investigate the development of melanocytes, other melanin-containing cells and the amount of melanin in stria vascularis from birth to adult age in the gerbil which has a uniform pigmentation of the fur and eyes, is born without hearing but establishes hearing function at 14-18 days after birth. Changes in the melanin morphology, concentration and distribution have been correlated to the development of the inner ear and to the time period during which hearing function is established, which indicates that the melanocytes in stria vascularis are of importance for the hearing function.

Age Factors↗
PubMed1992

The interaction of smoking and noise on temporary threshold shifts.

Four separate experiments examined the effects of cigarette smoking on temporary threshold shifts (TTS) following noise exposure. One experiment compared smokers and non-smokers after the subjects had abstained from smoking for at least 6 h. A second experiment tested only smokers who smoked a cigarette just before noise exposure, during the noise exposure and in a control condition during which they did not smoke. A third experiment tested only non-smokers who were exposed to noise after chewing nicotine gum or after a control condition in which they rested without chewing the gum. A fourth experiment tested smokers and non-smokers in one condition which required them to smoke a cigarette just prior to noise exposure and in another condition which prevented them from smoking. The results indicate that smokers consistently evidence slightly smaller TTS than do non-smokers. Non-smokers evidenced significantly greater TTS at one frequency after they had chewed nicotine gum than when they had not. These results suggest that the smaller TTS associated with cigarette smoking is related to both the chronic and the acute effects of smoking and that these effects may be more attributable to carbon monoxide than to nicotine.

Adolescent↗
PubMed1992

Psychological and audiological correlates of perceived tinnitus severity.

Beliefs and attitudes towards tinnitus have been found to play an important role in the process of rehabilitation. The relationship between audiological, psychological and psychosomatic factors (self-assessment of vertigo and headache and the perceived severity of tinnitus) was investigated in a clinical population of 163 subjects. Audiological descriptives comprised pure-tone average (dB HL), etiology of hearing loss, duration of tinnitus and tinnitus localisation. Perceived severity of tinnitus was assessed with a questionnaire focusing on tinnitus impact on aspects of quality of life, concentration and sleep. A 28-item handicap and support questionnaire was used and factor analysed, resulting in three factors: perceived attitudes, social support and disability/handicap. Tinnitus severity was significantly related to perceived attitudes. The influence of social support on tinnitus severity did not seem to be crucial. The results showed that significantly more women than men complained about vertigo. Unilateral tinnitus localisation was also more prevalent in females. The subjects with multiple tinnitus localisations were older and had significantly more sleep disturbance than subjects with tinnitus localized to the ears only. In accordance with previously reported observations, the frequency of headaches was strongly correlated with the severity of tinnitus.

Adaptation, Psychological↗
PubMed1992

Acupuncture for tinnitus management.

Fifty-six patients with continuous and severe tinnitus as their major complaint were treated with traditional Chinese acupuncture. After a pre-treatment period with baseline evaluation of tinnitus, 10 treatments were given during a period of 20 days, followed by a post-treatment period in order to obtain indications of prolonged treatment effects. Assessments were made using visual analogue scales (VAS) and a verbal retrospective rating scale. Three patients reported improvement which lasted for at least 10 days after the last treatment, indicating a possible long-term effect in some cases. Twenty-one percent of the patients reported transient intensity reductions lasting for hours/days. Estimated 'substantial' improvement rate by VAS, consistent for all three parameters involved (intensity, annoyance, awareness), was 20%, while the corresponding deterioration rate was 25%. Statistical analysis of the whole group did not show any significant general treatment effects. Interactions between treatment evaluations by verbal rating and VAS are discussed as well as interactions with psychological components.

Acupuncture Points↗
PubMed1992

Noise levels from toys and recreational articles for children and teenagers.

This study examined the noise level emitted by toys and recreational articles used by children and teenagers. The results indicate that many of the items tested emit sufficiently intense noise to be a source of noise induced hearing loss in school-age children. While the baby toys provided noise exposure within the limits of national regulations, they are most intense in a frequency range that corresponds to the resonance frequency of the external auditory canal of very young children. Hobby motors emit noise that may require protection depending upon the length of use. Fire-crackers and cap guns emit impulse noises that exceed even conservative standards for noise exposure.

Adolescent↗
PubMed1991

Simulation of batch and continuous reactors with co-immobilized yeast and beta-galactosidase.

A reaction-diffusion model was used to simulate a co-immobilized system utilizing the numerical method of orthogonal collocation. The production of ethanol from deproteinized whey using beta-galactosidase co-immobilized with Saccharomyces cerevisiae in calcium alginate gel beads was chosen as a model system. Calculated concentrations of lactose, glucose, galactose and ethanol were compared with experimental data for a batch reactor and a continuous horizontal packed-bed reactor. The mathematical model has been used to analyse the influence of internal and external mass transfer for the continuous reactor. The external mass transfer was shown to be of minor importance. The introduction of baffles decreased the backmixing in the horizontal packed-bed reactor. Internal mass transfer was found to be the main cause of the reduction in the apparent reaction rate. Thus, much of the expected increase in reaction rate is diminished by mass transfer hindrance when the cell concentration is increased.

Alginates↗
PubMed1991

Inner ear damage from toy cap pistols and fire-crackers.

Groups of guinea pigs comprising 7 animals in each group were exposed to 10, 50 or 100 exposures to fire-crackers or 10, 50 or 100 exposures to toy cap pistol shots. An additional group of 7 animals comprised the control material. The exposures were performed with 15-s intervals at 0.25 m distance for the toy cap pistol shots and at 0.8 m for the fire-crackers. The peak sound level at the ear was 155 dBC for both impulsive sounds. After a 3-week survival period the animals were anesthetized and decapitated. The cochleas were examined histologically in surface preparations and read double-blind. One animal in each group exposed to 10 fire-crackers and 10 toy cap pistol shots showed sensory cell loss. With 50 or 100 toy cap pistol shots or fire-cracker exposures, 24 out of 28 animals showed pronounced sensory cell loss. The present results clearly indicate the risk for noise-induced hearing loss in children playing with toy cap guns and fire-crackers.

Animals↗
PubMed1991

Psychological dimensions in patients with disabling tinnitus and craniomandibular disorders.

Forty-two patients with severe tinnitus and craniomandibular disorders (CMD) are presented from an audiological and psychological point of view. During a 2-week period, the patients rated their mood and their tinnitus. Based upon mood ratings, patients were grouped into three clusters (high, medium and low mood). The three groups differed in a number of respects, audiological as well as psychological. Patients in the low mood group experienced significantly more intense and severe tinnitus and more daily stress than patients in the high mood group. Ratings of irritation and concentration difficulties seemed to be mood related, and discriminated between patients in the low mood group and patients in the moderate and the high mood groups. Difference in hearing level between the left and the right ear was more pronounced in patients with low mood. There were, however, no significant differences between the groups in the stomatognathic variables. It is concluded that the above mentioned audiological and psychological observations should be considered as potentially important for satisfactory management of individual tinnitus patients. Further studies of the effects of optimally compensated hearing on depressed mood in patients with noise-induced hearing loss (NIHL) and tinnitus are required.

Affect↗
PubMed1990

Prevalence of signs and symptoms of craniomandibular disorders in tinnitus patients.

One hundred two tinnitus patients were examined to determine the prevalence of signs and symptoms of CMD. The examination comprised determination of the anamnestic and clinical dysfunction indices according to Helkimo; assessment of the dentition, occlusal factors, and signs of parafunctions; and accomplishment of a tension test. Patients also answered a questionnaire concerning the presence and frequency of CMD symptoms and headaches, as well as influence on tinnitus by mandibular movements, by pressure applied to the TMJ, or by dental therapy. Frequent headaches and fatigue/tenderness in jaw muscles were more prevalent in tinnitus patients than in epidemiologic samples, as was the prevalence of clinical findings of pain on palpation of masticatory muscles, impaired mandibular mobility, and signs of parafunctions. About one-third of the patients reported influence on tinnitus by mandibular movements and/or pressure applied to the TMJs. A theoretic model of causal connections between tinnitus and signs and symptoms of CMD in some tinnitus patients is suggested.

Adolescent↗
PubMed1989

Noise and vibration interactions: effects on hearing.

There is the suggestion in the literature that vibration may potentiate the effects of noise and may thus increase the risk of hearing loss in a variety of exposure situations. However, in human experimental studies, which, by necessity, are limited to low levels of exposure, the effects measured are relatively small. A very limited number of animal studies have also shown an enhanced noise-induced hearing loss in the presence of vibration, but the scope of these studies is limited. The animal studies (chinchilla) that form the basis of this report were performed using a 30-Hz, 3g rms and a 20-Hz, 1.3g rms cage vibration separately and in combination with continuous noise (95-dB, 0.5-kHz octave band) and impact noise (113, 119, or 125 dB peak SPL) exposure paradigms. All exposures lasted for 5 days. The impact noise exposures were designed to have approximately equal total energy. Temporary and permanent threshold shifts were measured using evoked potentials, and sensory cell loss was measured using surface preparation histology. The results obtained from some of the noise/vibration paradigms showed that such exposures can alter some of the dependent measures of hearing. This effect was statistically significant only for the stronger vibration exposure conditions and was evident primarily in the extent of the outer hair cell losses and in the shape of the PTS audiogram.

Animals↗
PubMed1989

The influence of carbogen on susceptibility to TTS.

A group of 20 male subjects were exposed to noise in each of four separate conditions. In two conditions they inhaled carbogen (95% oxygen, 5% carbon-dioxide). In two others they inhaled compressed air. In two conditions they were exposed to noise after inhalation and in two they were exposed to noise during the inhalation. The results indicated that carbogen inhalation reduced the magnitude of TTS but only in the 'During' condition.

Adolescent↗