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1.
Transplant Proc ; 51(4): 1263-1267, 2019 May.
Article in English | MEDLINE | ID: mdl-31101211

ABSTRACT

Thoracic organ transplantation made a fresh start in Hungary with the first double lung transplant in December 2015. This major leap in Hungarian transplantation was preceded by almost 10 years of preparation, new infrastructure development, and structural changes not only at the organizational level but in human resources as well. In the following years, until recently, altogether 47 lung transplants were performed on 24 men and 23 women. The underlying pathologies were as follows: chronic obstructive pulmonary disease, 25; cystic fibrosis, 11; idiopathic pulmonary fibrosis, 7; as well as other diseases, including bronchiectasis, eosinophilic granuloma, lymphangioleiomyomatosis, and primary pulmonary hypertension in 4 cases. The youngest recipient was 13 and the oldest was 65 years old. Overall survival rates at 30 days and at 1 year were 96% and 82%, respectively. No patients were lost in the cystic fibrosis and other diseases group, whereas the 1-year survival rates of the chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis groups were 73% and 71%, respectively. The results show the robustness and viability of the program, although there is still opportunity for further improvement. In this short paper, we summarize the fields of possible further cooperation of thoracic and cardiac teams as well as future challenges facing the new Hungarian lung transplant program.


Subject(s)
Cardiology , Lung Diseases/surgery , Lung Transplantation/methods , Lung Transplantation/statistics & numerical data , Adolescent , Adult , Aged , Female , Humans , Hungary , Male , Middle Aged , Surgeons , Survival Rate , Young Adult
2.
Transplant Proc ; 51(4): 1296-1298, 2019 May.
Article in English | MEDLINE | ID: mdl-31101218

ABSTRACT

Lung transplant is an effective way to treat many end-stage lung diseases. However, one of the main barriers of allograft organ transplant is still the immunologic rejection of transplanted tissue, which is a response of the HLA molecules. Rejection is a complex process involving both T-cell-mediated delayed-type hypersensitivity reactions and antibody-mediated hypersensitivity reactions to histocompatibility molecules on foreign grafts. We report the case of a 25-year-old female patient with cystic fibrosis who underwent 2 lung transplants because of her initial diagnosis and appearance of bronchiolitis obliterans syndrome after the first transplant. Only 13 months after the second transplant, despite the therapies applied, a new rejection occurred associated with high mean fluorescent intensity donor-specific antibody levels, which resulted later in the death of the patient. The present case draws attention to the importance of matching HLA molecules between donor and recipient in addition to immunosuppressive therapy.


Subject(s)
Cystic Fibrosis/surgery , Graft Rejection/immunology , Lung Transplantation/adverse effects , Reoperation/adverse effects , Adult , Bronchiolitis Obliterans/etiology , Bronchiolitis Obliterans/surgery , Female , HLA Antigens/immunology , Humans , Transplantation, Homologous/adverse effects
3.
Transplant Proc ; 49(7): 1535-1537, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28838435

ABSTRACT

The first successful lung transplantation was done in 1963 by James Hardy in the United States. The Vienna Lung Transplant program was launched in 1989 by Professor Walter Klepetko, and in 1996 lung transplantation became available in this center also for Hungarian patients. By 2013, conditions for full-scale Hungarian lung transplantation program were ripe. The Hungarian government invested 3 million Euros for infrastructural developments that made the operation and the perioperative care available. Besides funding, the professional training of medical personnel was also essential for this program to start. Hungarian specialists have had internship opportunities to study all aspects of lung transplantation at the Thoracic Surgery Department in Vienna. After successful preparations, the first lung transplantation in Hungary was performed on December 12, 2015.


Subject(s)
Lung Transplantation , Program Development , Humans , Hungary , Program Evaluation
4.
Transplant Proc ; 49(7): 1538-1543, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28838436

ABSTRACT

Until December 2015, Hungarian patients' lung transplantations (LTXs) were done at the Medical University of Vienna. After several years of preparation, the National Hungarian Lung Transplantation Program was launched and the first milestone LTX was performed in Budapest on December 12, 2015. During the first 12 months, 18 lung transplantations took place in Hungary, including the first one. Data were retrospectively collected to analyze the early postoperative problems of the first 18 LTX patients of the newly launched Hungarian National Lung Transplantation Program. No patients with primary pulmonary hypertension and no children were transplanted during this period. We found that the postoperative problems of LTX differ from those of other huge thoracic surgeries both in a quantitative and a qualitative manner. We also reveal problems that are not present with other thoracic surgeries. The wide variety of problems during the early postoperative period after LTX can be managed by a highly organized and coordinated interdisciplinary teamwork.


Subject(s)
Lung Transplantation/adverse effects , Postoperative Complications/etiology , Female , Humans , Hungary , Male , Middle Aged , Postoperative Period , Program Evaluation , Retrospective Studies
5.
Transplant Proc ; 49(7): 1544-1548, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28838437

ABSTRACT

Lung transplantation (LUTX) became a worldwide accepted standard therapy for certain well-defined chronic end-stage lung diseases. Until recently, patients on mechanical ventilation or extracorporeal life support techniques were hardly eligible for LUTX because of the inferior short-term results. However, a paradigm shift has occurred, and now these techniques represent bridging options to LUTX for listed patients. In the current practice, transplantation from the intensive care unit (ICU) is not extraordinary in patients on the waiting list. On the other hand, transplantation of an ICU patient who has previously been healthy without any chronic lung disease is still exceptional. Here we report a unique case of a 37-year-old woman without any relevant medical history who developed acute lung failure based on a cryptogenic organizing pneumonia. Her condition rapidly deteriorated and she required mechanical support, then she was bridged to transplantation on venovenous extracorporeal membrane oxygenation. She was listed for LUTX, and despite elevated panel-reactive antibody values, positive crossmatch LUTX was performed. Induction therapy, alemtuzumab, plasmapheresis, and intravenous immunoglobulin were administered. Her recovery was slow but finally she could be discharged from hospital in stable condition. After 2 months at home, she was readmitted to the hospital with respiratory failure from combined antibody-mediated rejection and infection. Before December 2015, the launch of Hungarian National Lung Transplantation Program, Hungarian patients were transplanted in Vienna. This case presents an exceptional example of national and international teamwork that aimed to save a young woman's life.


Subject(s)
Cryptogenic Organizing Pneumonia/complications , Lung Transplantation/methods , Respiratory Insufficiency/surgery , Acute Disease , Adult , Cryptogenic Organizing Pneumonia/pathology , Disease Progression , Extracorporeal Membrane Oxygenation , Female , Humans , Immunosuppression Therapy , Respiration, Artificial , Respiratory Insufficiency/etiology
6.
Nanoscale ; 7(10): 4406-10, 2015 Mar 14.
Article in English | MEDLINE | ID: mdl-25686156

ABSTRACT

Optical effects in template-directed colloidal assembly are explored to fabricate microscale patterns with integrated three-dimensional (3D) nanostructures. This method allows the patterning of periodic nanostructures in arbitrarily designed regions by controlling particle assembly and light illumination. Using both "bottom-up" and "top-down" methods, this approach enables low-cost fabrication of hierarchical devices.

7.
Parkinsonism Relat Disord ; 8(3): 171-6, 2002 Jan.
Article in English | MEDLINE | ID: mdl-12039427

ABSTRACT

Previous research on tremor pathophysiology showed that tremor can be affected, e.g. by electrical stimulation of the peripheral nerve, mechanical perturbation of the limb and by transcranial magnetic stimulation of the motor cortex. This report is focused on possible effects of muscle vibration (MV) on resting tremor in Parkinson's Disease (PD). Vibratory stimulation was applied to the tendons of M. extensor carpi radialis longus and M. flexor ulnaris in 27 subjects with moderate PD resting tremor. The following effects were observed: (1) tremor stopped or started time-locked to MV onset and offset, (2) tremor persisted during MV but its frequency pattern changed. These results are discussed with specific emphasis to effects of MV on spinal and supraspinal levels.


Subject(s)
Parkinsonian Disorders/physiopathology , Proprioception/physiology , Tremor/physiopathology , Vibration , Aged , Aged, 80 and over , Electromyography , Female , Forearm/physiopathology , Humans , Male , Middle Aged , Tendons/physiopathology , Time Factors
8.
Clin Neurophysiol ; 112(4): 636-40, 2001 Apr.
Article in English | MEDLINE | ID: mdl-11275536

ABSTRACT

OBJECTIVE: Although the therapeutic effects of botulinum toxin A can be explained by its action at the neuromuscular junction, central or more proximal effects have also been discussed. METHODS: Eleven patients with torticollis spasmodicus and 3 patients with writer's cramp were studied before and 1 and 5 weeks after the first treatment with botulinum toxin. We measured compound muscle action potentials (CMAPs), motor conduction velocities (MCVs), the shortest (SFL) and the mean F-wave latencies (MFL) and F-wave persistence (30 trials) of untreated muscles for each side (ulnar nerve-abductor digiti minimi muscle, peroneal nerve-tibialis anterior muscle). RESULTS: CMAPs and MCVs showed no significant changes. For both nerves, however, SFL and MFL were prolonged slightly 1 week after treatment and returned to about baseline after 5 weeks (t test). The F-wave persistence was reduced 1 week after treatment for the right ulnar and both peroneal nerves (t test). CONCLUSIONS: These results are not likely due to an impairment of neuromuscular transmission. Instead, we propose a decreased excitability of alpha-motoneurons supplying non-treated muscles. A reduction of muscle spindle activity or changes of the recurrent inhibition are discussed as possible causes.


Subject(s)
Action Potentials/physiology , Botulinum Toxins, Type A/therapeutic use , Dystonic Disorders/drug therapy , Muscle Contraction/physiology , Muscle, Skeletal/drug effects , Torticollis/drug therapy , Adult , Botulinum Toxins, Type A/administration & dosage , Dystonic Disorders/physiopathology , Female , Humans , Male , Middle Aged , Muscle, Skeletal/physiology , Peroneal Nerve/physiopathology , Time Factors , Torticollis/physiopathology , Ulnar Nerve/physiopathology
9.
In Vivo ; 14(1): 173-82, 2000.
Article in English | MEDLINE | ID: mdl-10757075

ABSTRACT

High throughput gene expression profiling is increasingly becoming a desirable method for identifying genes differentially expressed in disease versus normal tissues. Microarrays and gene chips containing hundreds to thousands of genes of interest, both known and novel, can be used to establish the expression profile of numerous genes in a single experiment. In order to validate the hits emerging out of such an experiment it is necessary to use an appropriate panel of the cDNA repository. We investigated the usefulness of such a method to identify prostate cancer-specific genes. A microarray containing 588 known genes was analyzed using cDNA probes derived from normal and three independent prostate tumors. At least 19/588 genes were found to be differentially expressed in the tumors in comparison to the normal tissue. Among the nine test genes chosen, one gene, Glutathione-S-transferase theta 1 (GSTT1), showed a correlation with the microarray results when analyzed by RT-PCR. Using a comprehensive panel of normal and tumor tissues and cancer-derived cell lines, we have rapidly validated the expression relevance of GSTT1 in solid tumors. The microarray was also useful in the preliminary identification of androgen-regulated genes in the prostate tumor models. These results indicate that microarray in combination with a relevant cDNA repository can facilitate rapid identification of potential targets for therapy and diagnosis of prostate and other cancers.


Subject(s)
Gene Expression Profiling , Oligonucleotide Array Sequence Analysis/methods , Prostatic Neoplasms/genetics , Female , Gene Expression Regulation, Enzymologic , Gene Expression Regulation, Neoplastic , Glutathione Transferase/genetics , Glutathione Transferase/metabolism , Humans , Male , Prostatic Neoplasms/enzymology , RNA/genetics , RNA, Neoplasm/genetics , Reverse Transcriptase Polymerase Chain Reaction , Tissue Distribution , Tumor Cells, Cultured
10.
Anticancer Res ; 20(1A): 53-8, 2000.
Article in English | MEDLINE | ID: mdl-10769634

ABSTRACT

The expressed sequence tag (EST) databases are an attractive starting point for gene discovery for diseases like cancer. Validation of gene targets from these sequences (both known and novel) in cancers requires a comprehensive expression profiling. We identified from the Cancer Gene Anatomy Project database (CGAP), a hit called neurotensin receptor (NT-r) that was expressed in the pancreatic cancer cDNA libraries. Neurotensin (NT), a neuroendocrine peptide, exerts trophic effects in vivo and stimulates the growth of cancer-derived cell lines in vitro. High affinity neurotensin receptors (NT-r) are expressed in cancer-derived cell lines and in some primary tumors. To date, a comprehensive expression profile of the NT-r in diverse cancers and normal tissues has not been reported. A cancer-selective expression of NT-r, if demonstrable, may provide a basis for a diagnostic and potential therapeutic utility. We demonstrate that the NT-r is expressed in a variety of cancer-derived cell lines as well as primary tumors, but only in a select few normal tissues. The expression of NT, on the other hand, was detected in many normal tissues, but not in the cancer-derived cell lines. The NT expression however, was detected in the primary tumors. We further demonstrate that NT expression is stimulated by androgen deprivation in the prostate cancer models. These results demonstrate the usefulness of a panel of cDNA repository for rapid validation of potential cancer targets.


Subject(s)
Gene Expression Regulation, Neoplastic , Neoplasm Proteins/genetics , Neoplasms/genetics , Receptors, Neurotensin/genetics , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Colonic Neoplasms/genetics , Colonic Neoplasms/metabolism , DNA, Complementary/genetics , DNA, Neoplasm/genetics , Databases, Factual , Female , Gene Expression Profiling , Gene Library , Humans , Male , Neoplasm Proteins/biosynthesis , Neoplasms/metabolism , Organ Specificity , Ovarian Neoplasms/genetics , Ovarian Neoplasms/metabolism , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/metabolism , Prostatic Neoplasms/genetics , Prostatic Neoplasms/metabolism , RNA, Messenger/biosynthesis , RNA, Messenger/genetics , RNA, Neoplasm/biosynthesis , RNA, Neoplasm/genetics , Receptors, Neurotensin/biosynthesis , Tumor Cells, Cultured
11.
Adv Exp Med Biol ; 384: 161-71, 1995.
Article in English | MEDLINE | ID: mdl-8585448

ABSTRACT

We recorded twitch parameters of motor units of the human first dorsal interosseus muscle applying low-rate intramuscular microstimulation of motor axons (IMS) or spike-triggered averaging (STA). The values of contraction time, half-relaxation time and maximal rate of rise of force were significantly smaller in the STA studies. The reduction corresponded to the effect expected from partial twitch fusion. Twitch amplitudes, however, were not smaller than those in the IMS studies, indicating that other factors, such as motor unit synchronization, compensate for the effects of partial fusion.


Subject(s)
Axons/physiology , Motor Neurons/physiology , Muscle Contraction/physiology , Adult , Amyotrophic Lateral Sclerosis/physiopathology , Electromyography , Female , Hereditary Sensory and Motor Neuropathy/physiopathology , Humans , Male , Middle Aged , Muscle Denervation , Muscular Atrophy/physiopathology
12.
Electroencephalogr Clin Neurophysiol ; 93(2): 100-5, 1994 Apr.
Article in English | MEDLINE | ID: mdl-7512915

ABSTRACT

We recorded twitches of single motor units (MUs) in the human first dorsal interosseus muscle using either spike-triggered averaging (STA; 236 MUs in 12 normal subjects) or low-rate intramuscular microstimulation of motor axons (IMS; 200 MUs in 20 normal subjects). We analysed twitch force (TF), maximal rate of rise of force (MRRF), contraction time (CT) and half-relaxation time (HRT). MRRF, CT and HRT were significantly smaller with STA than with IMS whereas TFs were fairly similar. Higher stimulus rates (up to 14 Hz) in IMS resembling the voluntary MU firing rates in STA were associated with a decrease of all twitch parameters because of partial fusion of the twitches (20 MUs). Concerning MRRF, CT and HRT, the reduced values matched those obtained by STA, suggesting that the underestimation of these parameters in STA can be mainly attributed to partial fusion. The reduction of TF with high rate IMS but not with STA reveals that other factors such as MU synchronization and non-linear force summation of MU contractions must counteract the effects of partial fusion in STA. We conclude that both STA and IMS are appropriate for assessing TFs in man while the time-dependent parameters MRRF, CT and HRT will be underestimated with STA.


Subject(s)
Motor Neurons/physiology , Muscles/physiology , Adult , Electric Stimulation , Electromyography/methods , Female , Humans , Male , Middle Aged , Muscle Contraction/physiology , Muscles/innervation , Time Factors
13.
Neurosci Lett ; 150(1): 21-4, 1993 Feb 05.
Article in English | MEDLINE | ID: mdl-8469397

ABSTRACT

Motor units (MUs) with low voluntary recruitment thresholds are the first to be activated by transcranial magnetic stimulation. It is not clear, however, if high-threshold MUs can also be activated and if they contribute to motor evoked potentials (MEPs). We therefore studied 11 high-threshold motor units in the first dorsal interosseous muscle of 11 healthy subjects. Voluntary recruitment thresholds ranged from 22 to 41% (29.5 +/- 5.6%; mean +/- S.D.) of maximal muscle force. When MUs were driven at their recruitment thresholds, transcranial magnetic stimuli were applied to the vertex. Peri-stimulus time histograms of MU discharges were constructed. All MUs studied revealed a period of increased firing probability at 19-27 ms after the stimulus (primary peak). Stimulus intensities were lower by 10-57% of the maximal stimulator output than required to produce near maximal MEPs in conventional surface EMG recordings in the same subjects. We conclude that high-threshold MUs can be activated by transcranial magnetic stimulation and that they contribute to conventionally recorded MEPs.


Subject(s)
Brain/physiology , Motor Activity , Transcranial Magnetic Stimulation , Adult , Evoked Potentials , Female , Humans , Male , Movement , Muscles/innervation , Muscles/physiology
14.
Muscle Nerve ; 15(10): 1138-42, 1992 Oct.
Article in English | MEDLINE | ID: mdl-1406771

ABSTRACT

M responses and twitch contractions were evoked in single motor units (MUs) of the first dorsal interosseus muscle by intramuscular microstimulation of motor axons. Two-hundred nine MUs were studied in 21 subjects. Thirty-five MUs (17%) showed F waves in addition to M responses. Twitch force was used to provide an indirect measure of MU size; additionally, twitch contraction time was measured. There was no select group of MUs generating F waves with regard to the above contraction parameters. However, four of five MUs with very high twitch forces, above 70 mN, generated F waves. We conclude that MUs of all sizes produce F waves with similar probability. Only few MUs with very strong twitch forces, i.e., very large MUs, may be more subject to F-wave production and may be involved in the generation of the so-called repeater F waves.


Subject(s)
Motor Neurons/physiology , Muscles/innervation , Action Potentials/physiology , Adult , Axons/physiology , Electromyography , Female , Humans , Male , Middle Aged , Muscle Contraction/physiology , Muscles/physiology
15.
Article in German | MEDLINE | ID: mdl-1425390

ABSTRACT

It is still unknown why only few motor units (MUs) generate F-waves in response to supramaximal stimulation of a motor nerve. Therefore we investigated whether the F wave production might depend on MU-size. According to the size principle of Henneman we used the twitch force as indirect measure of MU-size. MU twitch force was determined applying the technique of intramuscular microstimulation of single motor axons. 127 MUs were analysed in 16 normal subjects. F-waves were observed in 35 MUs (27%). It was found that MUs of different sizes produced F-waves with approximately the same probability. Obviously size is not a relevant factor for the capability of a MU to produce F-waves. Only the few very large MUs of a pool may have an increased tendency to produce F-waves because four of five MUs with extremely large twitch forces (> 70 mN) generated F-waves.


Subject(s)
Electromyography , Motor Neurons/physiology , Adult , Humans , Middle Aged , Reference Values
16.
Orv Hetil ; 133(36): 2293-6, 1992 Sep 06.
Article in Hungarian | MEDLINE | ID: mdl-1383903

ABSTRACT

Six patients with obstruction of the trachea were treated with silicone rubber endothracheal stents implanted with flexible bronchoscope. In every case the stent caused significant clinical improvement of the ventilation. At the postintubation stenosis the stent can result a final recovery, at the malignant processes the implantation seems to be a new palliative method.


Subject(s)
Stents , Tracheal Stenosis/therapy , Accidents , Bronchoscopy , Fiber Optic Technology , Humans , Intubation, Intratracheal , Lung Neoplasms/complications , Palliative Care , Trachea/injuries , Tracheal Stenosis/etiology , Tracheal Stenosis/rehabilitation
17.
Neuromuscul Disord ; 2(4): 261-7, 1992.
Article in English | MEDLINE | ID: mdl-1483052

ABSTRACT

Intramuscular microstimulation of motor axons was used to study twitch responses of 209 motor units (MUs) in the first dorsal interosseus muscle (FDI) of 20 normal subjects. Twitch peak force (TF), maximum rate of rise of force (MRRF), contraction time (CT) and one-half relaxation time (HRT) were determined. The distributions of TF (mean 16.0 mN, median 10.3 mN) and MRRF (mean 0.88 N s-1, median 0.66 N s-1) were skewed to the right with the majority of the values lying in the lower ranges, whereas CT (mean 63 ms, median 62 ms) and HRT (mean 61 ms, median 58 ms) were approximately normally distributed. TF was significantly correlated with MRRF, but not with CT in contrast with studies of cat gastrocnemius muscle. TF values were similar to those obtained by spike-triggered averaging in the same muscle. The method proved to be reliable and appropriate for use in patients. Examples of MU twitch parameters from three patients with chronic partial denervation of the FDI are described.


Subject(s)
Muscle Contraction/physiology , Muscles/physiopathology , Adult , Electric Stimulation , Electromyography , Female , Humans , Male , Micromanipulation , Middle Aged , Muscles/innervation , Neuromuscular Diseases/physiopathology , Time Factors
18.
Ann Biomed Eng ; 20(2): 205-24, 1992.
Article in English | MEDLINE | ID: mdl-1575377

ABSTRACT

In this study we explored the possibility of suppressing pathological tremors using closed-loop functional electrical stimulation (FES) to activate the tremorogenic muscles out-of-phase. A displacement signal monitored with a transducer was filtered so as to be "tuned" to the tremor frequency at the wrist or elbow. The filtered signal was used to amplitude-modulate the electrical stimulation. The design process was based on measurements of the open-loop frequency response characteristics of the forearm and hand to stimulation of the elbow and wrist flexors and extensors in a number of subjects. These data allowed us to identify closed-loop configurations, which attenuated 2-5 Hz tremors substantially, while only minimally attenuating functional movements in the 0-1 Hz range. There was a fairly delicate balance between efficacy and the risk of instability. However, designs were identified that offered enough tremor suppression and adequate immunity to muscle/load variations for the technique to be considered seriously for clinical application.


Subject(s)
Electric Stimulation , Tremor/physiopathology , Forearm , Humans , Isometric Contraction/physiology , Movement/physiology , Muscles/physiology , Reference Values
19.
Ann Biomed Eng ; 20(2): 225-36, 1992.
Article in English | MEDLINE | ID: mdl-1575378

ABSTRACT

In this study we evaluated a technique for tremor suppression with functional electrical stimulation (FES), the technical details of which were described in the previous paper. Three groups of patients were investigated: those with essential tremor, parkinsonian tremor, and cerebellar tremor associated with multiple sclerosis. In each group, tremor was attenuated by significant amounts (essential tremor: 73%; parkinsonian tremor: 62%; cerebellar tremor: 38%). These attenuations were in good accord with predictions based on the dynamic analyses and filter designs derived in the previous paper. With filters "tuned" to the lower mean tremor frequency encountered in the cerebellar patients, more attenuation was possible in this group as well. We identified some practical limitations in the clinical application of the technique in its present form. The most important was that in daily use, only one antagonist pair of muscles can realistically be controlled. At first sight, this restricts the usefulness of the system to patients with single-joint tremors. However, the concomitant use of mechanical orthoses may broaden the scope of application.


Subject(s)
Electric Stimulation Therapy , Tremor/therapy , Adult , Cerebellar Diseases/complications , Data Interpretation, Statistical , Female , Humans , Male , Middle Aged , Movement/physiology , Multiple Sclerosis/complications , Parkinson Disease/complications , Pilot Projects , Tremor/etiology , Tremor/physiopathology
20.
Electroencephalogr Clin Neurophysiol ; 81(4): 279-83, 1991 Aug.
Article in English | MEDLINE | ID: mdl-1714822

ABSTRACT

Paired motor unit discharges (PDs), i.e., two discharges of the same motor unit (MU) with short interval, and their relation to tremor amplitude were studied in the first dorsal interosseous muscle (FDI) of patients with parkinsonian or essential tremor and in normal subjects mimicking tremor. In both pathological and voluntary tremor, interdischarge intervals of PDs were inversely correlated with the amplitude of the subsequent tremor beat, i.e., PDs with shorter intervals were followed by higher tremor beats. To further assess their mechanical impact, PDs were simulated by applying paired stimuli to MUs of the FDI in normal subjects using intramuscular microstimulation. Following paired stimuli, summation of twitch responses was more than linear. This was also the case with the paired stimuli applied at a tremor-like repetition rate (5 Hz). These findings stress the importance of PDs for tremor expression.


Subject(s)
Motor Neurons , Tremor/physiopathology , Adult , Aged , Electrophysiology , Humans , Middle Aged , Motor Neurons/physiology , Muscles/physiology
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