RESUMEN
BACKGROUND: Previous studies mostly did not separate between symptomatic disc herniation combined with osteochondrosis/spondylosis of the lumbar spine and symptomatic disc herniation in radiographically normal intervertebral spaces. This may at least in part explain the differences in the observed risk patterns. AIMS: To investigate the possible aetiological relevance of physical and psychosocial workload to lumbar disc herniation with and without concomitant osteochondrosis/spondylosis. METHODS: A total of 267 cases with acute lumbar disc herniation (in two practices and four clinics) and 197 control subjects were studied. Data were gathered in a structured personal interview and analysed using logistic regression to control for age, region, nationality, and diseases affecting the lumbar spine. Cases without knowledge about osteochondrosis/spondylosis (n=42) were excluded from analysis. Risk factors were examined separately for those cases with (n=131) and without (n=94) radiographically diagnosed concomitant osteochondrosis or spondylosis. RESULTS: There was a statistically significant positive association between extreme forward bending and lumbar disc herniation with, as well as without concomitant osteochondrosis/spondylosis. There was a statistically significant relation between cumulative exposure to weight lifting or carrying and lumbar disc herniation with, but not without, concomitant osteochondrosis/spondylosis. Cases with disc herniation reported time pressure at work as well as psychic strain through contact with clients more frequently than control subjects. CONCLUSIONS: Further larger studies are needed to verify the concept of distinct aetiologies of lumbar disc herniation in relatively younger persons with otherwise normal discs and of disc herniation in relatively older persons with structurally damaged discs.
Asunto(s)
Desplazamiento del Disco Intervertebral/etiología , Vértebras Lumbares , Enfermedades Profesionales/etiología , Adulto , Estudios de Casos y Controles , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Osteocondritis/complicaciones , Esfuerzo Físico , Postura , Factores de Riesgo , Osteofitosis Vertebral/complicaciones , Estadística como Asunto , Estrés Psicológico/complicaciones , Carga de TrabajoRESUMEN
BACKGROUND AND PURPOSE: An animal model of incomplete forebrain ischemia resembling human hemodynamic insufficiency was established. The model allows examination of acute and chronic changes of local cerebral blood flow (lCBF) and reserve capacity in correlation with behavioral parameters. METHODS: Anesthetized male Wistar-Kyoto rats underwent bilateral carotid occlusion (BCO). Laser-Doppler scanning of lCBF at baseline conditions and after acetazolamide was done 30 minutes after BCO, motor and memory function tests were administered after 1 and 2 days, and both investigations were repeated after 1, 2, 4, and 6 weeks. A sham-operated and a control group without any vessel manipulation served as controls. RESULTS: lCBF dropped within 60 minutes after surgery by 62% (P<0.001) in 10 animals surviving BCO (BCOsurvival) and by 69% in 5 rats that died within 9 days (BCOlethal). Acetazolamide increased lCBF to 142.33% in controls, to 136.66% in sham-operated rats (both significant), and to 104.80% in BCOsurvival (not significant), and it decreased flow by 23.1% in BCOlethal rats (P<0.001). Baseline lCBF normalized within 4 weeks. Total motor function scores were significantly reduced from 9 points preoperatively to 5.80+/-0.65 in BCOlethal and 6.68+/-0.54 points in BCOsurvival rats 1 day after occlusion. Memory retention function remained impaired after BCO, as did the acetazolamide response, which correlated with motor score and was inversely related to maze exploration time. CONCLUSIONS: This model allows long-term follow-up of cerebral function, lCBF, and reserve capacity in a pathophysiological setting similar to hemodynamic insufficiency in humans.
Asunto(s)
Arteriopatías Oclusivas/fisiopatología , Isquemia Encefálica/fisiopatología , Circulación Cerebrovascular/fisiología , Memoria/fisiología , Neuronas Motoras/fisiología , Acetazolamida/farmacología , Animales , Anticonvulsivantes/farmacología , Conducta Animal , Presión Sanguínea , Arterias Carótidas , Circulación Cerebrovascular/efectos de los fármacos , Enfermedad Crónica , Modelos Animales de Enfermedad , Conducta Exploratoria , Flujometría por Láser-Doppler , Masculino , Aprendizaje por Laberinto , Ratas , Ratas Endogámicas WKYRESUMEN
The assessment of the cerebrovascular reserve capacity (RC) has become a widely used tool in the management of cerebrovascular disease. Discrepancies become obvious, however, if results obtained with different methods are compared. Aim of the present study, therefore, was to compare blood velocity and cerebral perfusion data in the same group of healthy test persons. In 32 volunteers regional cerebral blood flow (rCBF) was measured with the 133Xe-inhalation method. F1 as grey matter flow and the initial slope index (ISI) were computed. Simultaneously flow velocity in the middle cerebral artery (VMCA) was assessed by transcranial Doppler sonography (TCD). Measurements were performed in the resting state, during inhalation of 7% CO2 and after 1 g acetazolamide. Baseline VMCA was 62.38 +/- 16.1 cm/s, 90.84 +/- 23.85 cm/s during hypercapnia and 84.91 +/- 24.54 cm/s after acetazolamide. There was no significant change of baseline or stimulated values with age. F1 rose from baseline 76.25 +/- 12.48 ml/100 g/min to 103.90 +/- 14.6 ml/100 g/min in hypercapnia and to 98.4 +/- 14.9 ml/100 g/min after acetazolamide. The baseline F1 values and the response to CO2 decreased with age (p = 0.01) whereas for the acetazolamide reaction an age dependency could not be proven. ISI baseline values (41.5 +/- 6.1 ml/100 g/min) as well as those found after CO2 or acetazolamide decreased significantly with age. In hypercapnia changes of F1 and ISI were not too well related with changes of VMCA (F1: r = 0.599; ISI: r = 0.473), but better during acetazolamide exposure (F1: r4 = 0.715; ISI: r = 0.522). The age dependency of resting and stimulated values has to be considered when assessing the reserve capacity. There is a correlation between changes of the perfusion and flow parameters in healthy individuals which, however, may be worse in cerebrovascular disease.
Asunto(s)
Acetazolamida/farmacología , Dióxido de Carbono/farmacología , Circulación Cerebrovascular/efectos de los fármacos , Adolescente , Adulto , Anciano , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Arterias Cerebrales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valores de Referencia , Estimulación QuímicaRESUMEN
Regional cerebral blood flow (rCBF) was measured by means of the 133-Xenon inhalation method in 12 healthy male volunteers experienced in self-hypnosis for several months. During a well performed levitation of the right arm in hypnosis as compared to resting conditions, we found a global increase of cortical blood flow and a regional activation of temporal areas; the latter finding is considered to reflect acoustical attention. In addition, a so far unexplained desactivation of inferior temporal areas was observed during successful self-hypnosis and hypnosis. While there was a global absolute increase of cortical blood flow bilaterally, we could not observe a relative increase of the right as compared to the left hemisphere during hypnosis. Several subjects successfully performed the levitation of the right arm, despite a relative left hemispheric activation, provided the absolute right hemispheric activation remained dominant.