Changing phenotypic expression in a patient with a mitochondrial encephalopathy due to 13042G>A de novo mutation--a 5 year follow up

Mutations in NADH dehydrogenase (ND) subunits of complex I lead to mitochondrial encephalomyopathies associated with various phenotypes. This report aims to present the patient's clinical symptomatology in the context of a very rare 13042G>A de novo mutation and with an emphasis on changing phenotypic expression and pronounced, long-standing response to levetiracetam.

Muscle pathology in myotonic dystrophy: light and electron microscopic investigation in eighteen patients

Myotonic dystrophy (DM) is the most common muscular dystrophy in adults. Two known genetic subtypes include DM1 (myotonic dystrophy type 1) and DM2 (myotonic dystrophy type 2). Genetic testing is considered as the only reliable diagnostic criterion in myotonic dystrophies. Relatively little is known about DM1 and DM2 myopathology. Thus, the aim of our study was to characterise light and electron microscopic features of DM1 and DM2 in patients with genetically proven types of the disease. We studied 3 DM1 cases and 15 DM2 cases from which muscle biopsies were taken for diagnostic purposes during the period from 1973 to 2006, before genetic testing became available at our hospital. The DM1 group included 3 males (age at biopsy 15-19). The DM2 group included 15 patients (5 men and 10 women, age at biopsy 26-60). The preferential type 1 fibre atrophy was seen in all three DM1 cases in light microscopy, and substantial central nucleation was present in two biopsies. Electron microscopy revealed central nuclei in all three examined muscle biopsies. No other structural or degenerative changes were detected, probably due to the young age of our patients. Central nucleation, prevalence of type 2 muscle fibres, and the presence of pyknotic nuclear clumps were observed in DM2 patients in light microscopy. Among the ultrastructural abnormalities observed in our DM2 group, the presence of internal nuclei, severely atrophied muscle fibres, and lipofuscin accumulation were consistent findings. In addition, a variety of ultrastructural abnormalities were identified by us in DM2. It appears that no single ultrastructural abnormality is characteristic for the DM2 muscle pathology. It seems, however, that certain constellations of morphological changes might be indicative of certain types of myotonic dystrophy.

Elevated levels of anti-Chlamydia pneumoniae IgA and IgG antibodies in young adults with ischemic stroke

INTRODUCTION

Data on the role of Chlamydia pneumoniae in patients with ischemic stroke are inconsistent. We investigated the presence of anti-C. pneumoniae antibodies in young adults with ischemic stroke.

METHODS

94 patients (<55 years) with ischemic stroke and 103 controls were enrolled. Indices of anti-C. pneumoniae IgA and IgG were assessed with an ELISA. We determined OR and 95% CI for the IgA and IgG seropositivity in stroke cases.

RESULTS

Mean IgA and IgG indices were higher in stroke patients vs controls (IgA: 1.40 vs 0.56; P < 0.001; IgG: 0.85 vs. 0.78; P < 0.003). The IgA seropositivity was associated with stroke risk (11.92; 5.94-23.92; P < 0.001) as well as IgG seropositivity was (2.31; 1.15-4.61; P < 0.016). Seropositivity assessed with combined IgA and IgG indices was associated with increased stroke risk (OR 9.35; 95% CI 4.78-18.29; P < 0.0001). After controlling for age and sex, the IgA seropositivity yielded a significantly adjusted OR for stroke (8.95; 4.44-18.07; P < 0.002), while IgG seropositivity did not (0.85; 0.53-1.63).

CONCLUSIONS

We find an increased risk of stroke in young patients seropositive to C. pneumoniae in the IgA antibody class. Further studies to explore this finding are warranted.

Serum IgM anti-GM1 ganglioside antibodies in lower motor neuron syndromes

Lower motor neuron syndromes (LMNS) are heterogenous conditions, which include patients with progressive lower motor neuron disease (LMND) and cases with the clinical phenotype of motor neuropathy (MN). The aim of this study was to estimate the IgM anti-GM1 ganglioside antibodies titer and the ratio of the light chains in order to define the presence of autoimmunity process in particular cases with LMNS. Twenty-eight patients were diagnosed with LMND and 15 patients were diagnosed with MN (10 patients with multifocal motor neuropathy with conduction block, five patients with MN without conduction block). Total of 103 patients with classical amyotrophic lateral sclerosis (ALS) and 50 healthy, age-matched persons were also tested. The IgM anti-GM1 ganglioside titer and the ratio of lambda/kappa light chains in serum were determined using the ELISA technique. High titer of IgM anti-GM1 antibodies were detected in serum of 46% LMND patients, 80% of MN patients, and 18% of the classical ALS cases. An elevated ratio of lambda/kappa light chains appeared in 18% of LMND patients, and in 67% of the MN cases. The lambda/kappa light chains ratio was normal in all ALS patients. The presence of elevated titer of IgM anti-GM1 ganglioside antibodies and the changed ratio of the light chains supports the presence of autoimmune process in LMNS and may provide clues for their management.

CADASIL: new cases and new questions

We described the first two unrelated Polish families with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). In the morphological examination with light microscopy, two kinds of changes were observed: (1). panarteritis nodosa-like changes with eosinophilic fibrinoid necrosis of the vessel wall and perivascular inflammatory infiltrates and (2). basophilic granular material in the tunica media characteristic of CADASIL. At electron microscopy, we found deposits of granular osmophilic material (GOM) within the wall of arteries, veins and capillary vessels. Our findings imply two questions requiring further investigation: Why in the genetically determined vascular disorder are the features of systemic inflammatory vascular disease present? Why in capillary walls deprived of smooth muscle cells are deposits of GOM present?

Effect of Riluzole on serum amino acids in patients with amyotrophic lateral sclerosis

OBJECTIVES

There is evidence that an imbalance between glutamatergic and inhibitory neurotransmission may contribute to selective neurodegeneration in amyotrophic lateral sclerosis (ALS). The efficacy of Riluzole in prolonging the survival of patients with ALS has been demonstrated in two large controlled trials. It is believed that Riluzole is a glutamate antagonist, but the exact mode of its action is not known. Data on the effects of Riluzole treatment on excitotoxic amino acid levels in serum are not available.

MATERIAL AND METHODS

We prospectively studied 17 patients with ALS (diagnosed according to the El Escorial criteria), who received long-term treatment with Riluzole (100 mg/day). The subjects were evaluated at baseline (before treatment) and after 6, 12 and 18 months on drug. Assessments included the functional status of the patients and serum levels of amino acids. Analysis of the serum amino acids was performed using high performance liquid chromatography techniques at baseline, and after 6, 12 and 18 months of the treatment.

RESULTS

At baseline, glutamate, GABA and total amino acid concentration in serum of the ALS patients, mainly in those with severe course of the disease, were increased. During the first 6 months of Riluzole treatment there was a significant decrease of glutamate and total amino acids, afterwards the values returned to the initial high values, or even an 'overshooting' in their levels appeared. We did not observe a similar effect of Riluzole on glutamate and other amino acids in patients with less advanced ALS.

CONCLUSIONS

It is suggested that the positive clinical effect of Riluzole in ALS patients may be related, at least partly, to its influence on amino acid metabolism in neural tissues.

[Kennedy's disease: expansion of the CAG trinucleotide]

Kennedy's disease is a rare X-linked spinal and bulbar muscular atrophy (SBMA). A degenerative process of the motor neurons is associated with an increase in the number of CAG repeats encoding a polyglutamine stretch within the androgen receptor. Despite a distinctive clinical phenotype, SBMA can be misdiagnosed, usually due to the lack of clear family history. Accurate diagnosis is important for genetic counseling and because alternative diagnosis of amyotrophic lateral sclerosis usually means much worse prognosis. We report 2 unrelated patients with Kennedy's disease in whom the clinical diagnosis was confirmed by showing the CAG repeat expansion.

[Neurotoxic activity of serum and cerebrospinal fluid of amyotrophic lateral sclerosis patients against some enzymes of glutamate metabolism]

One of the hypotheses in amyotrophic lateral sclerosis (ALS) indicates on excitatory amino acids as the cause of neuronal death. Changes in their concentration in the tissues and body fluids may be the consequence of a defect in their transport, as well as abnormal activities of glutamate metabolizing enzymes. Abnormal synthesis/degradation of these enzymes and/or influence of activators/inhibitors should be taken into account. The activity of enzymes of glutamate metabolism of rat spinal cord in vitro in the presence of serum and cerebrospinal fluid (CSF) of 20 patients with ALS and 20 healthy controls was tested. In the presence of serum of the ALS patients glutaminase was significantly stimulated, instead of being inhibited; the inhibition of GABA aminotransferase, glutamate decaboxylase and aspartate aminotransferase was less evident than in the controls, glutamate dehydrogenase lost its activity more than in control conditions, the inhibition of glutamine synthetase was comparable to that when normal serum was applied. The activity of the enzymes in the presence of CSF of ALS patients was generally similar to that of normal CSF, except of glutaminase which was stimulated and GABA aminotransferase, which was inhibited stronger than in the presence of normal CSF. This study indicates, that changes in glutamate concentration in tissues and body fluids in ALS may be caused, at least partly, by abnormalities in the activity of glutamate metabolism enzymes, which are in turn induced by neurotoxic agents present in body fluids of ALS patients.

[The effect of selegiline and vitamin E in the treatment of ALS: an open randomized clinical trials]

A role for oxidative stress in the etiology or progression of amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases has been recently proposed. We conducted the 18-month, randomized treatment trial with oral vitamin E (600 IU daily) and selegiline (10 mg daily) in 67 patients with sporadic ALS. Thirty five patients were randomly assigned to receive antioxidative therapy (vitamin E plus selegiline) and the remaining 32 patients were the ALS controls who received symptomatic treatment. The primary end point was survival and functional status. At the end of 18-month study, 13 patients in the treatment group and 14 in the control group died or were tracheostomized. A decline in functional disability was also similar in both groups. Long-term antioxidative treatment did not benefit patients with ALS.

[Symptomatic treatment and palliative care of ALS]

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease, affecting upper and lower motor neurons, which eventually progresses to respiratory deterioration and death in most of the patients. Only one drug, riluzole, has been approved for the treatment of ALS. The drug has a benefit, prolonging life by 3-6 months, but the disease progresses inexorably, with no better quality of life. The fundamental role of medicine is sometimes to cure, but always to bring comfort. In current situation, ALS patients need adequate palliative care more than anything else. Prognosis and treatment options should be discussed with the patient and the relatives, but full information about the prognosis may deprive the patient of hope. However, disclosure of the prognosis is necessary to obtain informed consent for management decisions such as tracheostomy and artificial ventilation. Nasal positive-pressure ventilation (BiPAP) is an alternative to tracheostomy, at least for some patients without advanced bulbar impairment. Nutritional status in patients who cannot swallow can be efficiently improved by a percutaneous endoscopic gastrostomy. (PEG).

[The role of mitochondrial respiratory chain in the pathogenesis of ALS]

Mitochondrial dysfunction and abnormal electron chain transport (ECT) may be involved in the pathogenesis of ALS. The aim of this study was to investigate the effect of cerebrospinal fluid (CSF) from ALS patients on the activity of ECT enzymes in mitochondrial cerebral crude preparations in the rats. We found that CSF inhibited the activity of complex I-III in 20%, complex II-III in 12% and complex IV in 33% of the ALS patients. CSF from the controls did not affect the activity of complex I-III and II-III. The effect of the CSF ultrafiltrates with cut off below 5000 daltons on the activity of ECT enzymes was also investigated. The CSF ultrafiltrates inhibited the activity of complex I-III, complex II-III and complex IV in 38%, 44% and 53% of the ALS patients, and in 80%, 53% and 43% of the controls, respectively. The results of this study and our previously reported experiments on the sera of ALS patients may indicate that neurotoxic effects of body fluids from ALS patients could be mediated by inhibition of the respiratory chain enzymes. This confirms an important role of mitochondrial dysfunction in the pathogenesis of ALS.

[Proton MR spectroscopy studies of the brain in ALS patients]

Nuclear magnetic resonance spectroscopy (MRS) has an ability to measure brain metabolites noninvasively in vivo. The content of N-acetyl-aspartate (NAA) is used as a biochemical marker of neuronal integrity and viability. In amyotrophic lateral sclerosis (ALS) patients the degeneration and neuronal loss of motor cortex was reported. The presence of these changes can lead to the decrease of NAA. The aim of this study was to evaluate the neurochemical status of motor cortex (by using 1H-MRS) in 11 patients with clinically definite or probable forms of ALS (according to the El Escorial criteria). These data were compared with MRS results from 4 healthy controls. The mean NAA/(Cr + PCr) values were decreased by 19% (p < 0.05) when compared with controls. In 4 ALS patients the NAA/(Cr + PCr) ratio was decreased by 31% (p < 0.05) and these patients had rapidly progressing disease. In other 7 ALS patients, we found that NAA/(Cr + PCr) was decreased by 10% (p < 0.05) and they showed less advanced neurological symptoms. 1H-MRS of the motor cortex can be a new diagnostic tool in ALS and it might help to monitor the progress of the disease.

[Transcatheter closure of patent foramen ovale in patients after cryptogenic stroke]

Paradoxical embolism through a patent foramen (PFO) is a possible mechanism of ischaemic stroke in patients with cryptogenic stroke. Occlusion of PFO in such patients is considered by some authors as most effective in stroke prevention. We present our initial experience with transcatheter closure of PFO with the new self-expanding device--the Amplatzer PFO occluder in three young patients (age < 50 years). Each of them experienced at least one ischaemic stroke episode, without a left heart or carotid source and each had an interatrial communication with right-to-left shunting during Valsalva manoeuvre on echocardiography. The PFO's were closed completely without complications, under transoesophageal echo guidance in general anaesthesia. Complete closure was confirmed at one-month follow-up echocardiogram in each patient. No repeat cerebral accidents occurred at that time. The procedures were relatively easy and the clear presentation of the implant on TEE and fluoroscopy, made implantation fully controlled. The unique feature of the device is, that until release it can easily be retrieved, repositioned or removed. Transcatheter closure of PFO with the Amplatzer PFO occluder may become the new therapeutic option for patients with cryptogenic stroke and presumed paradoxical embolism.

[A case of neurogenic dysphagia responding to nitrates]

We described a 47-year-old man with ischemic stroke who developed a brainstem syndrome with persistent dysphagia. He was fed by the nasogastric tube placed intermittently by himself for almost 7 months after the stroke. Elective feeding via percutaneous endoscopic gastrostomy (PEG) was not accepted by the patient. All treatment attempts with benzodiazepines, antidepressants and spasmolytic agents were unsuccessful. Videofluoroscopic investigation revealed excessive and long-lasting spasm of the upper esophageal sphincter which was associated with the massive aspiration of the contrast. The patient dramatically improved after treatment with nitroglycerin and long-acting nitrates with almost complete recovery of normal swallowing. A strikingly good effect of nitrates in the treatment of oropharyngeal dysphagia is emphasized by the authors.

Anti-neural antibodies in serum and cerebrospinal fluid of amyotrophic lateral sclerosis (ALS) patients

OBJECTIVES

An autoimmune basis has been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). This hypothesis is supported by the presence of antibodies that interact with motoneuron antigens in serum of these patients. Against autoimmunity are the discrepances in the frequency of the antibodies appearance and also failure of immunosuppression. The aim of our study was to evaluate the titer of antibodies against GM1-gangliosides, AGM1-gangliosides and anti-sulfatides in paired serum and cerebrospinal fluid samples in the ALS patients.

MATERIAL AND METHODS

Serum of 103 and CSF of 79 patients with ALS was examined. The "disease controls" consisted of 22 cases of other motor neuron diseases and 50 healthy, age-matched normals. CSF was drawn at the same time from 79 ALS patients, 6 cases of the "disease controls" and 50 normals. To study the titer of antibodies against GM1-gangliosides, AGM1-gangliosides and sulfatides the ELISA technique has been applied.

RESULTS

An increased titer against GM1-gangliosides, AGM1-gangliosides and sulfatides in ALS appeared in serum in 18%, 32%, and 11%, resp., in the "disease controls" the increased antibodies titer appeared in single cases. In CSF the appropriate values in ALS were 20%, 15%, 8%, resp. In the "disease controls" a high antibodies titer was a rare finding.

CONCLUSIONS

It is concluded that in some ALS cases and also in some patients with other motor neuron diseases an autoimmune mechanism may contribute to motor neuron injury.

[Hereditary neuropathy with liability to pressure palsies caused by 17p11.2 chromosome deletion]

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disorder characterised by recurrent mononeuropathies. Electrophysiological studies reveal slowed conduction velocity in peripheral nerves. The main histopathological findings are focal thickenings of myelin-tomaculae. In most cases HNPP is associated with a deletion within PMP-22 (peripheral myelin protein; PMP) gene on chromosome 17p11.2. The gene penetration is almost complete but the expression may be variable. DNA analysis is of practical importance in diagnosing HNPP especially in sporadic cases and also in individuals without clinical and electrophysiological signs of neuropathy. We present the first Polish family with HNPP, in which the genetic defect has been confirmed by DNA analysis.

[Intracerebral hemorrhage following amphetamine use]

We describe a young male who suffered intracerebral hemorrhage (ICH) following nasal use of amphetamine. He recovered completely within several weeks of hospitalization. Angiography and MRI did not reveal vascular malformation and therefore we suspect that the ICH in our patient may be attributed to the effect of amphetamine alone.

[Disorders of neuromuscular transmission]

Disorders of neuromuscular transmission include a heterogenous group of diseases affecting the neuromuscular junction. The most important clinical syndrome is idiopathic myasthenia gravis. As a group, these disorders exhibit several common features, the essential one being a fluctuating fatigability and weakness of muscles. In this short review the molecular pathogenesis of different myasthenic syndromes is discussed.

ApoE polymorphism in Polish patients with Alzheimer's disease

Alzheimer's disease is a genetically heterogeneous disorder of CNS. The presence of APOE-epsilon 4 allele is known to increase the risk of early and late onset sporadic and late onset familial forms of AD. In various Western European countries, USA, Canada, Japan and Australia the allelic frequency ranges between 0.1-0.18 in controls, and between 0.24-0.52 in AD patients. In the present study on Polish population, we analyzed the frequency of APOE-epsilon 4 allele in persons with Alzheimer's disease (AD). APOE genotypes were determined in 30 mild to moderate AD (83%) and mixed dementia (MIX, 17%), as well as in 11 nondemented first-degree relatives of AD (NDR), recruited from AD patient registry in Warsaw. Among the AD and MIX patients the APOE-epsilon 4, epsilon 3, epsilon 2 allele frequency was 0.333, 0.65 and 0.017 respectively.

Mutations in the human skeletal muscle chloride channel gene (CLCN1) associated with dominant and recessive myotonia congenita

Myotonia, defined as delayed relaxation of muscle after contraction, is seen in a group of genetic disorders that includes autosomal dominant myotonia congenita (Thomsen's disease) and autosomal recessive myotonia congenita (Becker's disease). Both disorders are characterized electrophysiologically by increased excitability of muscle fibers, reflected in clinical myotonia. These diseases are similar except that transient weakness is seen in patients with Becker's, but not Thomsen's disease. Becker's and Thomsen's diseases are caused by mutations in the skeletal muscle voltage-gated chloride channel gene (CLCN1). Genetic screening of a panel of 18 consecutive myotonia congenita (MC) probands for mutation in CLCN1 revealed that a novel Gln-68-Stop nonsense mutation predicts premature truncation of the chloride channel protein. Four previously reported mutations, Arg-894-stop, Arg-338-Gln, Gly-230-Glu, and del 1437-1450, were also noted in our sample set. The Arg-338-Gln and Gly-230-Glu mutations were found in patients with different phenotypes from those of previous reports. Further study of the Arg-338-Gln and Gln-230-Glu alleles may shed light on variable modes of transmission (dominant versus recessive) in different families. Physiologic study of these mutations may lead to better understanding of the pathophysiology of myotonia in these patients and of voltage-gated chloride channel structure/function relationships in skeletal muscles.

A cerebrospinal fluid turnover in Parkinson's disease

In 30 patients with Parkinson's disease (PD) CT scan, isotopic cisternography and neuropsychological examination were performed to test possible relationship between cerebrospinal fluid (CSF) turnover, intellectual impairment and brain atrophy. Pathological cisternography was found in one third of the patients and it was positively correlated with the Columbia Rating Scale. Cerebral atrophy on CT was found more frequently in patients with earlier onset of PD. Combined pathological pattern on CT scan and on cisternography was correlated with intellectual decline. We conclude from this study, that in PD intellectual deterioration and brain atrophy separately are not connected with abnormal CSF turnover.

[Nocturnal paroxysmal hemoglobinuria--case report]

Paroxysmal nocturnal hemoglobinuria (PNH)-a case report. We present clinical and postmortem findings in patient with PNH who developed cerebral thrombosis. The pathogenesis of the PNH is discussed.

[Neurosarcoidosis or Guillain-Barre syndrome complicating sarcoidosis]

We described a young male with severe Guillain-Barré syndrome in whom pulmonary sarcoidosis was also detected. Based upon the results of diagnostic procedures (nerve biopsy, CSF examination, electrophysiological study) we postulate that this was a Guillain-Barré syndrome coexisting with sarcoidosis, and not the case of sarcoid neuropathy.

[Neurogenic pulmonary edema: case report and analysis of pathogenesis]

We describe a young female with subarachnoid haemorrhage (SAH) who developed neurogenic pulmonary edema (NPE). The symptoms of NPE were associated with severe mitral regurgitation. Both NPE and mitral insufficiency were completely reversible. The pathogenesis of NPE and cardiac injury is discussed.

[Myasthenic crisis during pregnancy: case report and literature survey]

We report the successful use of high-dose intravenous immunoglobulins during pregnancy in a young woman with myasthenic crisis. To our knowledge, immunoglobulins in the management of myasthenic crisis during pregnancy have not been previously described. It is emphasized that both the patient and her fetus tolerated the treatment well.

On the legacy of Joseph Babiński

Joseph Babiński pioneered development of French neurosurgery and world clinical neurology. Although he was best known for his discovery of the extensor plantar response, his foundations in the modern semiology of neurology are unequivocal. He introduced the concepts and terminology of cerebellar symptoms and discovered a reflex asymmetry as the sign of organic disease. Although he considered the development of French neurosurgery by his pupils as his greatest accomplishment, it is 'the sign' that has dominated his legacy over the years. This sign will also celebrate a centenary in 1996.

Dihydropyridine receptor mutations cause hypokalemic periodic paralysis

Hypokalemic periodic paralysis (hypoKPP) is an autosomal dominant skeletal muscle disorder manifested by episodic weakness associated with low serum potassium. Genetic linkage analysis has localized the hypoKPP gene to chromosome 1q31-q32 near a dihydropyridine (DHP) receptor gene. This receptor functions as a voltage-gated calcium channel and is also critical for excitation-contraction coupling in a voltage-sensitive and calcium-independent manner. We have characterized patient-specific DHP receptor mutations in 11 probands of 33 independent hypoKPP kindreds that occur at one of two adjacent nucleotides within the same codon and predict substitution of a highly conserved arginine in the S4 segment of domain 4 with either histidine or glycine. In one kindred, the mutation arose de novo. Taken together, these data establish this DHP receptor as the hypoKPP gene. We are unaware of any other human diseases presently known to result from DHP receptor mutations.

Sodium channel mutations in paramyotonia congenita and hyperkalemic periodic paralysis

Clinical and electrophysiological data have outlined a spectrum of similar yet distinct periodic paralyses, including potassium-sensitive (hyperkalemic periodic paralysis [HYPP]) and temperature-sensitive (paramyotonia congenita [PC]) forms. Recent work has revealed that these disorders result from allelic defects in the alpha-subunit of the adult, human skeletal muscle sodium channel. We report an additional mutation, a leucine-->arginine substitution in the S3 segment of domain 4 (L1433R), that results in the PC phenotype. Five other HYPP and PC families have been ascertained, and previously reported sodium channel mutations have been identified in each. Characterization of these mutations and phenotypic variations in such families will contribute to the understanding of sodium channel structure and function relationships, as well as channel malfunction in the periodic paralyses.

Treatment of myotonia with antiarrhythmic drugs

The effects of disopyramide, phenytoin, mexiletine, and tocainide were compared in 30 patients with myotonic disorders. The severity of myotonia was assessed by clinical and electromyographic criteria at the end of each treatment phase lasting four weeks. Mexiletine (MXT) and tocainide (TCD) were found to be the most potent antimyotonic agents. The antimyotonic efficacy of MXT and TCD is explained by their fast-blocking effect on voltage-dependent sodium channels in the muscle membrane. The benefits of myotonia control with pharmacological agents must be weight against the risk of therapy in the individual patient. Because of the risks of hematologic problems, TCD is not recommended by us for the treatment of myotonia.

[Acute encephalopathy in ethylene glycol poisoning]

Poisoning with ethylene glycol is the most frequent poisoning in our country. Acute encephalopathy during this poisoning may be a cause of important diagnostic difficulties, especially in the initial phase of the poisoning, due to the variety of symptoms and signs. Three cases of this poisoning are reported. All patients were erroneously referred and admitted to neurological hospital department. It is postulated that in each case of coma of unknown aetiology with signs suggesting damage to the brain stem and hyperventilation arterial blood gasometric examination should be done and blood and urine should be taken for toxicological investigations. In the treatment of glycol poisoning the most important task is to correct metabolic acidosis and to apply early dialysis treatment in serious intoxication.

[Respiratory insufficiency in patients with myasthenia gravis]

We evaluated 20 patients who required prolonged mechanical ventilation for respiratory failure associated with myasthenia gravis. All 20 patients survived and were weaned from the ventilator after 3 to 14 days (mean 6.5 days) of respiratory support. Progressing bulbar symptoms and respiratory infection were the most frequent causes of the myasthenic crisis. During a period of assisted mechanical ventilation, anticholinesterase medication was interrupted and the patients were treated with steroids and antibiotics. Plasmapheresis may be considered in the management of myasthenic crisis.

Drug-induced myotonia in human intercostal muscle

The myotonia-inducing effects of furosemide and clofibrate, two widely used pharmaceutical agents, were investigated in excised human external intercostal muscle. The effects of anthracene-9-carboxylic acid (9-AC), a well-known myotonia-producing chemical, were also tested for comparison. In the presence of these drugs the electrical threshold was lowered, and a constant current pulse produced multiple spiking. Short trains of direct stimuli were often followed by after-activity, and this caused a myotonia-like prolongation of muscle contraction. Voltage-clamp experiments showed that 0.05 mM anthracene-9-carboxylic acid, 1 mM furosemide, and 1 mM clofibrate decreased the chloride conductance of the muscle fiber membrane to 14, 18, and 40%, respectively, of the normal value, and the myotonia-inducing potency of the 3 drugs was correlated with the decreased chloride conductance. The potassium currents were not affected by these compounds.

Progressive supranuclear palsy with lower motor neuron involvement. A case report

The clinical picture of progressive supranuclear palsy is relatively constant, including supranuclear ophthalmoplegia, pseudobulbar palsy, axial dystonia in extension, parkinsonian signs, postural instability and dementia. A case is reported, which is unusual in having flexor dystonia of the neck and marked signs of lower motor neuron involvement.

[Isaacs-Mertens syndrome: continuous activity of motor units]

The syndrome of Isaacs-Mertens is a rare neuromuscular disease in which the motor unit is continuously active. The diagnosis is based on electrophysiological methods and pharmacological tests. The involvement of laryngeal muscles observed in the reported female patient has been as yet rarely described in this syndrome. In the treatment long-term administration of carbamazepine 600 mg daily gave a considerable clinical improvement. The pathological mechanism of the syndrome is discussed in the light of the performed examinations and a review of the pertinent literature.

Membrane currents in human intercostal muscle at varied extracellular potassium

Hyperpolarizing and depolarizing square steps were imposed on the membrane potential of excised human intercostal muscle fibers by means of a 3-microelectrode voltage clamp. The steady-state amplitudes of the membrane currents inducing such steps were investigated as a function of the membrane potential, while the muscle was bathed in solutions varying in potassium content (Ke = 1, 3.5, 7, 20, and 60 mM). At all potassium concentrations, the membrane acted as a rectifier, both in the inward- and outward-going directions. Inward currents were much reduced when Ke was lowered from 3.5 to 1 mM, and were increased when Ke was raised beyond 3.5 mM. The delayed outward current was reduced when Ke was increased from 3.5 mM to 7 mM and higher potassium concentration. The results were qualitatively similar to those reported for rat skeletal muscle.

The resting membrane parameters of human intercostal muscle at low, normal, and high extracellular potassium

Membrane parameters at the respective resting potentials in low, normal, and high extracellular potassium solutions were determined in intercostal muscle fibers from 15 patients with no known neuromuscular disease. In synthetic interstitial fluid (normal potassium concentration 3.5 mmol/liter), we found the following mean values: resting membrane potential RP = -83.3 mV, space constant lambda = 2364 micron, fiber diameter d = 49.3 micron, fiber input resistance Rin = 795 k omega, specific membrane capacitance Cm = 4.7 muF/cm2, and specific membrane resistance Rm = 5970 omega X cm2. The specific membrane conductance was gm = 168 muS/cm2, 76% of it being chloride conductance, 24% being potassium conductance. The dependence of the membrane parameters on the extracellular potassium concentration followed the predictions by the constant field theory. There was no indication of active chloride transport. The resting membrane conductance decreased with temperature with a Q10 of 1.3. Excitability parameters were nearly independent of temperature between 37 and 27 degrees C.

Clofibrate-induced myotonia in rats

Determination of enzymatic activity, protein profile and phospholipid composition of muscle plasma membranes and sarcoplasmic reticulum in rats were carried out after clofibrate injections in a dose of 0.4 g/kg body weight. In the plasma membranes, the activity of Na+ + K+, Mg2+ ATPase was insignificantly decreased, and that of 5'-nucleotidase significantly diminished. A non-significant change was observed in the total amount of phopholipids. The amount of phosphoethanolamine appeared to be lower. Changes in the protein profile were seen. In the sarcoplasmic reticulum, the major abberation was the decrease of Mg2+ ATPase activity. No evident changes were observed in the phospholipid behaviour. Abnormalities in the protein profile appeared. In the myofibrillar proteins, increases of alpha-actinin and troponin at the expense of myosin were observed. In the clofibrate model of myotonia in rats, the changes in the biochemical parameters were less pronounced as compared to the previously tested 20,25-diazacholesterol model.

Treatment of myotonic dystrophy with acetazolamide

This report describes a patient with myotonic dystrophy who had severe action and percussion myotonia. The patient was unresponsive to diphenylhydantoin therapy. Treatment with acetazolamide, 250 mg daily, decreased the myotonia markedly. A possible mechanism of the favorable effect of acetazolamide in myotonia is discussed.

Myotonia induced with clofibrate in rats

Myotonia was induced in rats with clofibrate given in daily subcutaneous injections of 0.4 g/kg. The first myotonic discharges were recorded electromyographically from the extensor digitorum longus, tibialis anterior, and gastrocnemius muscles after 4 days on clofibrate, but from the soleus not until after 11 days. Clofibrate induced myotonic activity in chronically denervated muscle also. During repetitive nerve stimulation the electrical response of the muscle was declining in all myotonic rats. It did so also when repetitive stimulation was applied directly to the muscle, which would seem to suggest a myotonic defect as the cause. Several drugs were tested and diphenylhydantoin proved to inhibit myotonia most effectively. Animals on an extended clofibrate schedule (12 weeks) had ECG abnormalities resembling those seen in patients with myotonic dystrophy.

Sarcoplasmic reticulum in experimental myotonia in rats

Determinations of enzymatic activity, protein structure and phospholipid composition of sarcoplasmic reticulum isolated from the soleus muscle (S), extensor digitorum longus muscle (EDL) and gastrocnemius muscle (G) in rats were carried out after various periods of 20,25-diazacholesterol administration. The sarcoplasmic reticulum from G and EDL of myotonic rats exhibited a rise in basal ATP-ase activity and a fall of total phospholipids. The protein of molecular weight of 100000 daltons in G and EDL was slightly more pronounced.

Plasma membranes of muscle in experimental myotonia in rats

Determinations of protein and phospholipid composition, as well as enzymatic activity, were carried out in plasma membranes isolated from the muscle of rats, after different periods of 20,25-diazacholesterol administration. A decrease in the level of phospholipids, and in the total amount of plasma membrane proteins, connected with a relative reduction in the amount of protein of a molecular weight of 100000 daltons, was found. The activity of (Na+ + K+)-ATP-ase gradually decreased while a reverse tendency was observed in the case of 5'-nucleotidase. Changes in ATP-ase and phospholipids appeared even prior to electrophysiologically recorded signs of the myotonia. The mechanism of these changes and their possible role in myotonia are discussed.

Myofibrillar protein pattern in experimental myotonia in rats

Experimental myotonia was induced in rats by long-term administration of 20,25-diazacholesterol. Electrophysiological, morphological and biochemical investigations were carried out on m. soleus, m. extensor digitorum longus and m. gastrocnemius. The effect of 20,25-diazacholesterol administration on myofibrillar proteins was studied and a significant rise in the concentration of a protein presumed to be alpha-actinin was demonstrated in m. gastrocnemius. A change of the same character, not statistically significant, was observed in the m. extensor digitorum longus.

Neuromuscular failure in myotonic rats

Myotonia-like activity was recorded from various muscles of rats treated with 25-azacholesterol for a period of 2-8 weeks. 50% of myotonic rats showed a decline of amplitude of the evoked muscle potentials of the flexor digitorum muscle on stimulation of the median nerve with supramaximal stimuli at frequencies of 3, 5, 8, 15 or 50 cps. Administration of prostigimine increased neuromuscular failure. This temporary paresis of myotonic muscle resembles the transient impediment of motility of myotonic patients and it is entirely different from myasthenic transmission defect.