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G Drost

Publications and source records attributed to G Drost.

11 recordsLinked to original sources
PubMed2006

Drug treatment for myotonia.

BACKGROUND: Abnormal delayed relaxation of skeletal muscles, known as myotonia, can cause disability in myotonic disorders. Sodium channel blockers, tricyclic antidepressive drugs, benzodiazepines, calcium-antagonists, taurine and prednisone may be of use in reducing myotonia. OBJECTIVES: To consider the evidence from randomised controlled trials on the efficacy and tolerability of drug treatment in patients with clinical myotonia due to a myotonic disorder. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group trials register (April 2004), MEDLINE (January 1966 to December 2003) and EMBASE (January 1980 to December 2003). Grey literature was handsearched and reference lists of identified studies and reviews were examined. Authors, disease experts and manufacturers of anti-myotonic drugs were contacted. SELECTION CRITERIA: We considered all (quasi) randomised trials of participants with myotonia treated with any drug treatment versus no therapy, placebo or any other active drug treatment. The primary outcome measure was:reduced clinical myotonia using two categories: (1) no residual myotonia or improvement of myotonia or (2) No change or worsening of myotonia. Secondary outcome measures were:(1) clinical relaxation time; (2) electromyographic relaxation time; (3) stair test; (4) presence of percussion myotonia; and (5) proportion of adverse events. DATA COLLECTION AND ANALYSIS: Two authors extracted the data independently onto standardised extraction forms and disagreements were resolved by discussion. MAIN RESULTS: Nine randomised controlled trials were found comparing active drug treatment versus placebo or another active drug treatment in patients with myotonia due to a myotonic disorder. Included trials were double-blind or single-blind crossover studies involving a total of 137 patients of which 109 had myotonic dystrophy type 1 and 28 had myotonia congenita. The studies were of poor quality. Therefore, we were not able to analyse the results of all identified studies. Two small crossover studies without a washout period demonstrated a significant effect of imipramine and taurine in myotonic dystrophy. One small crossover study with a washout period demonstrated a significant effect of clomipramine in myotonic dystrophy. Meta-analysis was not possible. AUTHORS' CONCLUSIONS: Due to insufficient good quality data and lack of randomised studies, it is impossible to determine whether drug treatment is safe and effective in the treatment of myotonia. Small single studies give an indication that clomipramine and imipramine have a short-term beneficial effect and that taurine has a long-term beneficial effect on myotonia. Larger, well-designed randomised controlled trials are needed to assess the efficacy and tolerability of drug treatment for myotonia.

Humans↗
PubMed2006

[Case report: mast cell leukosis in a neonatal calf].

Multicentric mast cell tumours in a newborn Fleckvieh-calf are described. The calf showed clearly pronounced lesions over the whole body. The lesions were multiple raised, cutaneous, greyisch-red and partially ulcerated. It died three hours after birth. Pathohistological examinations resulted in multiple mast cell tumours within the dermis. In addition multifocal to diffuse mast cell aggregations were observed in several internal organs including the lymph nodes and the bone marrow. No evidence for the presence of bovine leukemia virus was found by both investigating a lymph node homogenate of the calf and a blood sample of the mother cow. In this paper the pathomorphology of this rare disease is described, a possible cause is discussed and a short review of the available literature is presented.

Animals↗
PubMed2005

[The spectrum of hereditary skeletal-muscle channelopathies].

Channelopathies are a heterogeneous group of genetic diseases in which a defective ion channel is responsible for the symptoms. They manifest as diseases of the heart, brain or skeletal muscle. Hereditary skeletal-muscle channelopathies are characterised by myotonia, periodic paralysis or a combination of both and can be categorised as chloride, sodium and calcium channelopathies. When there is myotonia, the skeletal-muscle membrane is overexcited. In cases of periodic paralysis, the skeletal-muscle membrane is inactive. It is difficult to classify hereditary muscle channelopathies on the basis of clinical criteria only. A more reliable diagnosis is made using DNA analysis. Scientific research should focus on genotype-phenotype relationships.

Humans↗
PubMed2003

Selective spatial information from surface EMG after temporal filtering: the application to interference EMG using cross-covariance analysis.

OBJECTIVE: An increased spatial resolution in multichannel surface EMG recordings would provide new possibilities for the investigation of intermuscular and intramuscular coordination. A known analytical solution for volume conduction allows the conclusion that a high pass filtered surface electromyography (SEMG) signal contains information from a smaller environment near the recording electrode and therefore provides a higher spatial resolution. METHODS: The present paper concerns experiments on 9 subjects to measure, from the human biceps brachii muscle during static isometric contraction, using multichannel surface EMG. Cross-correlation functions between bipolar SEMG channels were calculated and high pass filtered. RESULTS: The correlation peaks showed the signs of propagating action potentials. The spatial width in the direction perpendicular to the muscle fibres decreased with increasing cut-off frequency. There exists an optimal cut-off frequency, which provides the best spatial resolution. It correlates with the thickness of the subcutaneous fat layer which causes a minimum depth of the active muscle fibres measured. CONCLUSIONS: High pass filtered cross-covariance functions of bipolar SEMG channels have an increased spatial resolution perpendicular to the muscle fibre direction and the frequency content of the signals can potentially give an indication of the depth of the active muscle fibres.

Action Potentials↗
PubMed2003

Pyridostigmine in postpolio syndrome: no decline in fatigue and limited functional improvement.

OBJECTIVES: To investigate the effect of pyridostigmine on fatigue, physical performance, and muscle function in subjects with postpoliomyelitis syndrome. METHODS: 67 subjects with increased fatigue and new weakness in one quadriceps muscle showing neuromuscular transmission defects, were included in a randomised, double blind, placebo controlled trial of 60 mg pyridostigmine four times a day for 14 weeks. Primary outcome was fatigue (on the "energy" category of the Nottingham health profile). Secondary outcomes included two minute walking distance and quadriceps strength and jitter. Motor unit size of the quadriceps was studied as a potential effect modifier. The primary data analysis compared the changes from baseline in the outcomes in the last week of treatment between groups. RESULTS: 31 subjects treated with pyridostigmine and 31 subjects treated with placebo completed the trial. No significant effect of pyridostigmine was found on fatigue. The walking distance improved more in the pyridostigmine group than in the placebo group (by 7.2 m (6.0%); p<0.01). Subgroup analysis showed that a significant improvement in walking performance was only found in subjects with normal sized motor units. Quadriceps strength improved more in the pyridostigmine group than in the placebo group (by 6.7 Nm (7.2%); p = 0.15). No effect of pyridostigmine was found on jitter. CONCLUSIONS: Pyridostigmine in the prescribed dose did not reduce fatigue in subjects with postpoliomyelitis syndrome. However, it may have a limited beneficial effect on physical performance, especially in subjects with neuromuscular transmission defects in normal sized motor units.

Adult↗
PubMed2001

Propagation disturbance of motor unit action potentials during transient paresis in generalized myotonia: a high-density surface EMG study.

Patients with autosomal recessive generalized myotonia, or Becker's disease, often suffer from a peculiar transient paresis. As yet, the relationship between this transient paresis and the defect in the gene encoding for a voltage gated Cl- channel protein in the muscle membrane of these patients is unclear. In order to gain a better understanding of the electrophysiological properties of the muscle fibre membrane in these generalized myotonia patients, we have studied transient paresis with a novel high-density surface EMG (sEMG) technique. We conclude that the transient paresis is explained by a deteriorating muscle membrane function, ending in conduction block and paresis. Multi-channel sEMG during the period of force decline in transient paresis shows a decrease in peak-peak amplitude of the motor unit action potentials from endplate towards tendon. This disturbance increases with time and place, indicating a deteriorating membrane function, and ends in a complete blocking of propagation within seconds. Spatiotemporally, this leads to a V-shaped sEMG pattern. In a more general sense, this contribution shows how spatiotemporal information, available through non-invasive high-density sEMG, may provide novel insights into electrophysiological aspects of membrane dysfunction.

Action Potentials↗
PubMed2000

Recent progress in the diagnostic use of surface EMG for neurological diseases.

The different techniques to measure and analyze surface EMG are summarized with an emphasis on the clinician's point of view. The application of surface EMG in neurological disease is hampered by many inherent problems, especially the difficulties in extracting features of single motor units. However, the evolution of surface EMG from single bipolar recordings via a linear array of multiple electrodes to densely packed, multi-channel electrode arrays could in principle solve this problem. The added value of using multiple channels (up to 128) with an interelectrode distance of a few millimetres to obtain more spatial information is emphasized. At least for some muscles it is now possible to extract information from the surface EMG, conventionally thought to belong to the domain of needle EMG (for example the "electrical size" of motor units). The use of analysis techniques such as the estimation of muscle fiber conduction velocity has already proven to be of diagnostic value in several myopathies characterized by a disturbed membrane function and in metabolic myopathies with abnormal fatigue profiles. Future research should be directed at the development of analysis techniques enabling the extraction of more relevant motor unit variables from surface EMG signals.

Electromyography↗
PubMed2000

Cerebellar involvement as a rare complication of pneumococcal meningitis.

A 4-year old girl with meningitis, caused by streptococcus pneumoniae, developed a subcoma with respiratory insufficiency, followed by a severe cerebellar syndrome. Cerebellar involvement after regaining consciousness consisted of a symmetrical ataxia and mutism. This mutism changed into dysarthria and finally into normal speech. Magnetic resonance imaging revealed lesions in both cerebellar hemispheres, suggesting cerebellitis. She recovered with prompt antibiotic treatment.

Cerebellar Diseases↗
PubMed1991

Induction and characterization of monoclonal anti-idiotypic antibodies reactive with idiotopes of canine parvovirus neutralizing monoclonal antibodies.

Monoclonal anti-idiotypic (anti-Id) antibodies (Ab2) were generated against idiotypes (Id) of canine parvovirus (CPV) specific monoclonal antibodies (MoAbs). The binding of most of these anti-Id antibodies to their corresponding Id could be inhibited by antigen, thus classifying these anti-Id antibodies as Ab2 gamma or Ab2 beta. By inhibiting experiments it was shown that these anti-Id antibodies did not recognize interspecies cross-reactive idiotopes, but recognized private idiotopes, uniquely associated with the Id of the anti-CPV MoAb used for immunization. This classifies these anti-Id antibodies as non-internal image Ab2 gamma. The potential use of these non-internal image anti-Id antibodies for the induction of antiviral antibodies in the CPV system is discussed.

Animals↗
PubMed1981

Production and potential use of monoclonal antibodies against polio viruses.

Lymphocyte hybridomas secreting monoclonal antibodies against different strains of polio virus type 1, 2, or 3 have been produced. For this purpose Balb/C mice were immunized with purified and inactivated virus suspensions and their splenocytes were fused with P3X63Ag8 mouse myeloma cells. Screening for antibody production was performed in an enzyme-linked immunosorbent assay (ELISA). Antibodies were produced either in cell culture or in Balb/C mice by passaging the hybridomas as solid or ascitic tumors, after they had been cloned at least three times by limiting dilutions in microtiter plates. Specificities of a number of these monoclonal antibodies were determined in the ELISA and in a neutralization test using different polio virus subtypes. The results indicate that for epidemiological studies monoclonal antibodies may prove to be very useful tools. Also the use of monoclonal antibodies for vaccine production (affinity chromatography; characterization of viral substructures) and routine vaccine control purpose (antigen quantification; neutralization of vaccine virus) seems attractive. Two of the neutralizing monoclonal antibodies against polio virus type 1, showed a selective immunoprecipitation with VP1, which suggests that VP1 is an important polypeptide for the induction of neutralizing antibody in vivo.

Animals↗