Search PubMed⌕ Search

Biomedical subjects

D Claus

Publications and source records attributed to D Claus.

At least 145 records · Page 8Linked to original sources
PubMed1988

Cross-sectional epidemiological study on neurotoxicity of solvents in paints and lacquers.

In a multi-disciplinary retrospective study we examined 105 house painters employed for at least ten years (median 27 years, range 10-36 years). Fifty-three workers from various professions (non-painters), who were matched with regard to age, occupational training and socio-economic status served as the control group. In both groups no cases of a clinically manifest polyneuropathy or encephalopathy were found. The neurophysiological examinations (EEG and NCV-measurement) showed no differences in painters and controls that would indicate adverse effects of organic solvents. There were no cases with neuroradiological findings of a diffuse cerebral atrophy. Furthermore the evaluation of certain brain structures (ventricular diameter, cella media index) of the CAT films did not reveal any significant differences. In the neurobehavioral tests significant differences in the results were only found in the subtests "change of personality" and "short term memory capacity" in a subgroup of painters with repeated prenarcotic symptoms at the workplace. Ambient air monitoring measurements at 30 representative workplaces showed that the concentrations of the main components of the solvent-mixtures were well below the MAK-values. The results of the "Erlangen Painter Study" does not confirm former epidemiologic findings from other countries, mainly Denmark. However, there are some aspects, such as minor solvent exposure in German house painters, insufficient diagnostic and etiological procedures as well as misclassifications which may explain the different experiences.

Adolescent↗
PubMed1988

The influence of vibration on the excitability of alpha motoneurones.

Transcranial magnetic brain stimuli were delivered to 6 healthy subjects at different time intervals after the beginning of muscle vibration. Vibration of 6 sec duration in 4 subjects and of 100 msec duration in 6 subjects was applied to the right abductor digiti minimi muscle using an electromagnetic mechanical stimulator. The responses to brain stimuli were enhanced in this muscle when vibration began 9 msec before the transcranial stimulus, i.e., when the descending volley and the monosynaptic afferent Ia volley arrived simultaneously at the anterior horn cell. With long lasting vibration an enhancement of responses to brain stimuli was seen, which began after 120 msec and continued for up to 5 sec after the onset of vibration. This is consistent with a tonic, probably polysynaptic, excitatory Ia influence on homonymous alpha motoneurones, as well as the well known monosynaptic effect.

Action Potentials↗
PubMed1988

Hepatic artery thrombosis in pediatric liver transplantation.

The incidence of hepatic artery thrombosis was analyzed in a series of 59 consecutive liver transplants performed in 52 children less than 15 years of age at the University of Louvain Medical School, Brussels, from March 1984 to March 1987. This incidence was 17% for the whole series; it was increased in small recipients less than 3 years of age and less than 15 kg (23%) in weight, as well as when the liver was harvested from a small donor less than 15 kg in weight (38%). It was also increased when the donor liver was supplied by more than one artery. This incidence was markedly reduced by arterial revascularization from the aorta, either directly or by interposition of an iliac segment; the reduced-size livers had a much lower incidence of arterial thrombosis (5%) than the whole livers (23%). In the present series, we did not find any argument to support the view that poorly controlled rejection could be implicated in the pathogenesis of arterial thrombosis.

Adolescent↗
PubMed1988

Central motor conduction in degenerative ataxic disorders: a magnetic stimulation study.

Central motor conduction to small hand muscles was measured using magnetic stimulation of the motor cortex and electrical stimulation of proximal motor roots in 11 patients with Friedreich's ataxia, 10 patients with early onset cerebellar ataxia with retained tendon reflexes (EOCA) and 13 patients with late onset degenerative cerebellar disease (LOCD). Central motor conduction was abnormal in 91% with Friedreich's ataxia, 70% with EOCA and 38% with LOCD. Central motor conduction abnormalities were not specific to individual disorders but were more severe and were related to disease duration in Friedreich's ataxia and EOCA.

Adult↗
PubMed1988

[Interaction of transcranial magnetic stimulation and mechanical stimuli].

The influence of different mechanical stimuli on the excitability of spinal motoneurones was investigated in 5 different experiments using transcranial magnetic brain stimulation. A servo controlled moving coil was used to deliver rectangular mechanical stimuli or vibration to the right abductor digiti minimi muscle (ADM) thus exciting spindle primaries. With the ADM relaxed, vibration produced an early enhancement of compound responses (CMAPs) after transcranial magnetic brain stimuli. This is thought to be due to simultaneous arrival of the descending corticospinal volley and of the afferent la volley at the anterior horn cell. With long lasting vibration an enhancement of responses to brain stimuli continued up to 5 seconds after the onset of vibration. Voluntary muscle contraction increased the CMAP. CMAPs measured with voluntary muscle contraction plus mechanical muscle stimulation did not differ from those with muscle contraction alone. Therefore an excitatory influence of mechanical stimuli cannot be seen with ADM contracted.

Afferent Pathways↗
PubMed1988

[Liver transplantation in the child. The situation in Europe and personal results of the first 100 patients].

Pediatric liver transplantation in Europe has expanded rapidly during the last four years. The survival rate of the 254 children less than 15 years recorded in the European Registry on December 31, 1987 was 68% at one year and 61% at three years; nineteen centers have contributed to this activity, of which 11 had performed less than 5 cases each while two thirds of the experience was concentrated in three centers (Brussels, Cambridge, Hannover). The results obtained in the first 100 children (65% were younger than 3 years) who received a liver graft at the University of Louvain Medical Center in Brussels between March 1, 1984 and July 31, 1988 are reported. The survival rates (79% at one year and 73% at three year) which do not differ with regard to the age, the indication of the technical modalities (whole liver or reduced size livers) are strongly influenced by the clinical condition (84% vs 50% at one year in elective and emergency transplantations respectively). One third of the 122 grafts transplanted by the authors were reduced livers harvested from older and often adult donors. This technique provides results of equal quality and does not entail an increased rate of technical complications; on the contrary, the incidence of arterial thrombosis has been significantly reduced. Transplantation of a reduced size liver is safe and should be recommended even in elective conditions, in view of the dire shortage of small pediatric donors.

Adolescent↗
PubMed1988

[Perception of vibration. Normal findings and methodologic aspects].

Measurement of vibratory perception threshold was carried out on the internal malleoli of 73 healthy subjects and 26 diabetic patients with symptoms of polyneuropathy in their legs. The tests were done first with a tuning fork, using a measuring scale to reflect the amplitude of vibration, and then with an electromagnetic vibrameter (Somedic AB, Stockholm). The results obtained using the vibrameter were much more sensitive than those recorded with the tuning fork (12 and 3 pathological results respectively, in 26 patients). Vibratory perception sensitively reflects disturbances of the function of fast adapting mechanoreceptors and of thick myelinated sensory nerve fibres. The results proved to be readily reproducible. Some variability was noted in the normal values obtained: A further development of the method to exclude the influence of reaction times of patient and investigator on the results might reduce this variability.

Adult↗
PubMed1987

[Is the increase in brain volume of abstinent alcoholics a sequela of rehydration?].

A group of 30 alcoholics as identified using the MALT score were examined both within the first 36 h of alcohol withdrawal and then again at the end of a 10-day treatment in hospital. We looked for clinical signs of dehydration, water and electrolyte imbalance, and concentration of steroid metabolites in the urine. Cranial computed tomography was also performed twice, again at the beginning and end of the 10-day period. The size of cerebrospinal fluid spaces was calculated through measuring the frontal interhemisphere distance, the width of cortical sulci, the ventricle III diameter, the Cella media index and also the number of vermal sulci. All patients had a brain atrophy which did not disappear within the 10 days. The neuroradiological parameters remained completely unchanged in the control examination. However, the laboratory parameters of the internal milieu had normalized. Therefore, it is submitted that the shrinkage of the brain of alcoholics cannot be due to a reversible intra- or extracellulary dehydration. There was also no proof of a hormonal cause for the brain shrinkage. As a consequence other etiological factors gain importance, such as malnutrition or a toxic alcohol effect.

Adult↗
PubMed1987

Autosomal recessive and dominant forms of polycystic kidney disease are not allelic.

Linkage analysis has been carried out in 11 kindreds with autosomal recessive polycystic kidney disease (ARPKD) using the genetic marker 3'HVR, closely linked (theta = 0.05) to the gene of the autosomal dominant type. Close linkage (theta less than or equal to 0.20) between the locus of the marker and that of ARPKD can be excluded. These data strongly suggest that the loci for the autosomal recessive and dominant forms of polycystic kidney disease are not allelic.

Alleles↗
PubMed1987

Gordon's reflex phenomenon in Huntington's disease.

The patellar tendon jerk was examined quantitatively in 8 cases of Huntington's disease and in 27 controls using surface electrodes over the quadriceps femoris and biceps femoris muscles. The purpose was to investigate whether Gordon's patellar phenomenon was caused by a lack of antagonistic innervation or by late agonistic tonic reflex activity in Huntington's disease. Specific results could indicate that the patellar tendon jerk could be used as a diagnostic aid, as is the long loop reflex of hand muscles. A late tonic stretch response was found, appearing between 160 and 260 ms after the tendon tap. This response appeared in 6 out of the 8 Huntington's cases, even when Gordon's phenomenon was not observed. Therefore, it could be assumed that the tonic quadriceps activation gives rise to the clinically observed Gordon's phenomenon.

Adolescent↗
PubMed1987

[Single-fiber electromyography, examination technic and findings].

Single-fibre electromyography has become much easier because of the advantages offered by modern computerised EMG equipment. Fibre density, jitter and the frequency of blockings can thus be examined with relative reliability. The technique allows a sensitive diagnosis of disturbances of neuromuscular stimulus transmission. Furthermore, different pathological results obtained in patients suffering from neuropathies or myopathies (12 controls, 65 patients) proved the diagnostic value of single-fibre EMG. The method is a valuable addition to conventional EMG. The examination technique is described and illustrated by various examples.

Electromyography↗
PubMed1987

Methods of measurement of thermal thresholds.

Thermal tests were performed in 117 healthy subjects on the face, wrist and leg; 32 were tested on the legs with different rates of cooling and warming. Additionally 2 groups of diabetics (37 patients) were tested. Thermotesting was most sensitive on the legs using a rate of temperature change of 2.5-2.8 oC/s. Warm and cold perception should be tested separately. Cold perception testing is most sensitive. Combined tests of warm and cold thresholds as well as the testing of cool pain and heat pain do not improve results. Abnormal cold perception may be an early indicator of diabetic small fibre polyneuropathy, leading to cold trauma and ulcers on the feet.

Adult↗
PubMed1987

[Somatosensory evoked potentials following tactile skin stimulation].

Somatosensory evoked potentials were recorded for tactile stimuli applied to the fingers II and V as well as paravertebrally. The advantage of the painless mechanical stimuli is their specificity and the well defined stimulus localization. The question was therefore if the evoked responses are clearly demarcated. Nack potentials (N22: 22.5 and 22.3 ms) as well as cortical SEP's (P1: 33.2 and 32.8 ms) were easily to derive. It was also possible to get SEP's for segmental paravertebral tactile stimuli. For the finger stimulation an Erb's potential could not be recorded reliably.

Adolescent↗