Pyridostigmine kinetics in healthy subjects and patients with myasthenia gravis.

Comparative pyridostigmine kinetics in plasma were measured in 10 healthy subjects given 4 mg iv and 60 mg oral pyridostigmine bromide. As determined from the AUC ratio, oral availability was 11.5% to 18.9% (means = 14.3%). Mean t 1/2 of the plasma level decline after oral dosing was 200 minutes, twice as long as the terminal elimination t1/2 after intravenous infusion (97 minutes). Thus absorption may proceed at a slower rate than elimination. Comparison of intraindividual data revealed strict dependence of the AUC on the infused dose (2, 4, and 8 mg) in one subject and variability in AUC up to a factor of two when two subjects took oral pyridostigmine three times. Patients with myasthenia who were receiving continuous therapy with oral pyridostigmine had AUC values per unit dose corresponding to those in healthy subjects. Storage stability of pyridostigmine in plasma required acidification of samples and storage at -75 degrees C. When native plasma was kept at -20 degrees C, there was appreciable loss of pyridostigmine within 1 to 2 months, the extent of which depended on the initial concentration.

Intrathecal baclofen therapy for stiff-man syndrome and progressive encephalomyelopathy with rigidity and myoclonus.

We report on eight patients with stiff-man syndrome (SMS) or its "plus" variant, progressive encephalomyelopathy with rigidity and myoclonus (PERM) receiving intrathecal baclofen via pump. In six of the patients, follow-ups continued for approximately 2.5 to 6.5 years after pump implantation. Intrathecal baclofen was an effective last-resort alternative for patients who responded poorly to or did not tolerate oral antispasticity medications. General mobility increased, and spasms and rigidity were reduced; however, no complete remissions were observed either before or after pump implantation. PERM patients showed more severe and rapid progression of symptoms and more attacks of autonomic dysregulation than SMS patients. They also required higher doses and more rapid dosage increases. Complications of intrathecal baclofen therapy included spasm-induced rupture of the catheter, catheter dislocation causing radicular symptoms, and pump malfunction resulting in inaccurate dosage administration. Patients suffered fewer side effects with intrathecal baclofen than with oral medication, but overdose resulted in a transient, comalike state in one patient and sudden dosage reduction due to pump failure was fatal in another.

Paraneoplastic myasthenia gravis: detection of anti-MGT30 (titin) antibodies predicts thymic epithelial tumor.

It has been suggested that antibodies against non-acetylcholine receptor proteins of striated muscle are markers of the presence of a thymic epithelial tumor in patients with myasthenia gravis (MG). These antibodies may be measured using an immunofluorescence assay against striated muscle (anti-STR) or an ELISA with a recombinant 30-kd titin fragment (anti-MGT30). To directly compare anti-STR with anti-MGT30, we examined the sera of 276 consecutive patients with known or suspected MG. Definite diagnoses and thymic histology, if available, were correlated with the antibody assays. Of the 276 patients, 164 had MG. Thymic histology was obtained in 44 patients: 18 had lymphofollicular hyperplasia, 13 thymic epithelial tumors, 8 atrophy, and 5 were normal. When compared with anti-STR, anti-MGT30 showed a sensitivity of 69% (STR 77%), specificity of 100% (STR 56%, p = 0.026), negative predictive value of 82% (STR 77%), and positive predictive value of 100% (STR 56%, p = 0.003) for the identification of a thymic epithelial tumor versus thymic hyperplasia. We conclude that the anti-MGT30 ELISA is better than the anti-STR immunofluorescence assay for the diagnosis of paraneoplastic MG.

CD45 isoform expression in autoimmune myasthenia gravis.

In myasthenia gravis (MG), humoral and cellular immune mechanisms are involved in the autoimmune pathogenesis. In this study, we investigated the role of the CD45 molecule in MG, having recently reported an association in multiple sclerosis. CD45, a protein-tyrosine phophatase receptor type C (PTPRC), is essential for both thymic selection and peripheral activation of T and B cells. Our aims were to determine (a) the prevalence of a functional mutation in the CD45 gene (exon 4 77C --> G; prevalence analysis), and (b) the distribution of memory (CD45RO+) and naive (CD45RA+) T cells in the peripheral blood (subset analysis). T cells from 78 patients with generalised MG were stained with monoclonal antibodies against CD45RO, CD45RA, CD4 and CD8 and quantified by four-colour flow cytometry. The control panel for the prevalence analysis (a) consisted of 303 healthy individuals. (b) From those, 67 age- and sex-matched probands were randomly selected as controls for the subset analysis. Patients were stratified according to their MG onset age, thymic pathology and immunosuppressive treatment. Statistical analysis was performed by Fisher's exact test, asymptotic chi2 test, the two-sided Mann-Whitney test and Spearman's correlation coefficient. As a result, the 77C --> G mutation in exon 4 of the CD45 gene was found in 1 of 78 patients versus none of the 303 controls. Thus, no association was detected with this single nucleotide polymorphism in MG patients overall. Surprisingly, however, ratios of CD45RO+ to CD45RA+ T cells were lower among CD8+ T cells from patients with late-onset MG (P = 0.023). Thymoma patients also showed a similar trend among CD4+ and CD8+ T-cells, as expected. These differences were not related to immunosuppressive drug treatment or thymectomy (in the 67 informative patients). Since there is no other evidence for increased thymopoiesis in late-onset MG, we propose an altered subset balance in the circulation.

Retrograde changes in motor and sensory conduction velocity after nerve injury.

Nerve section is followed by a reduction of motor and sensory conduction velocity in the proximal segment of the injured nerve. This reduction of velocity is associated with retrograde changes in fiber size. If reinnervation does not occur within the next 1 1/2--2 years, retrograde degeneration of nerve fibers results, and the amplitude of the evoked nerve potential in the proximal segment of the injured nerve decreases. This retrograde degeneration is probably significant in view of the poor results frequently obtained after nerve transplantation which is carried out too late.

Adult-onset rod disease with abundant intranuclear rods.

The third case of adult-onset rod disease (nemaline myopathy) with abundant myofibrillar as well as intranuclear rods is described. The 61-year-old woman suffered from progressive weakness of proximal extremities and of the neck, mimicking polymyositis. Muscle biopsy revealed a striking myopathic pattern, with intranuclear rods occurring in 31% of the fibres. On light and electron microscopy and by immunohistochemical study, the rods differed from myofibrillar rods. The absence of alpha-actinin in intranuclear rods suggests an enhanced readiness of actin filaments to bind to diverse proteins, instead of overproduction of alpha-actinin as the pathogenetic basis of the rod formation.

Adrenoleukodystrophy in an adult female. A clinical, morphological, and neurochemical study.

A 43-year-old female with adrenoleukodystrophy (ALD) is described, who developed spastic tetraparesis, suffered grand mal seizures, and became stuporous and demented during the last 5 years of her life. Computed tomography revealed symmetrical hypodense lesions in the peritrigonal regions. Adrenal insufficiency was not evident except for skin pigmentation. The ultrastructure of a rectal biopsy specimen showed inclusions with lamellae and interspersed clefts in macrophages of the submucosal layer. At autopsy, the adrenals were found to contain large foam cells filled with similar inclusions. The brain cortex and the spinal cord were histologically normal. However, cerebral white matter exhibited widespread demyelination which spared only the arcuate fibres. In regions of less severe demyelination scattered inflammatory cells were seen. On electron microscopy, aggregates of typical paired leaflets with distinct intermediate lines were demonstrated in perivascular macrophages. Histochemical study showed these cells to contain free as well as esterified cholesterol. Gas chromatographic analysis of very long chain fatty acids (VLFA) from the demyelinated cerebral white matter showed a marked increase of C26:0 fatty acid in cholesterol esters and above-normal values for C24:0 and C24:1 in gangliosides. It is suggested that the condition was a heterozygote form of X-linked ALD. Patients with neurodegenerative symptoms with or without adrenal insufficiency can easily be screened for X-linked ALD by VLFA analysis in blood or cultured fibroblasts.

[Functional healing of compartment syndrome of the tibia. An analysis of follow-up results]. / Funktionelle Ausheilung nach Compartmentsyndrom des Unterschenkels. Eine Analyse der Spätergebnisse.

In a retrospective review 78 compartmental syndromes, treated between 1980 and 1988, were analyzed. The mean follow-up was 42 months. 43 patients (53%) suffered an traffic accident. Direct trauma forces predominated (66 patients). The functional results after crush injuries had been worser than after contusion injuries or direct trauma forces. The functional results depended from the posttraumatic interval of decompression. The later the fasciotomy the worser the functional results had been. A wide fascial decompression is necessary. Two cases of rebound compartmental syndromes after unilateral fasciotomy reveal the skin as an important limiting factor in severe cases of compartmental syndrome.

Accessory nerve stimulation in the assessment of myasthenia gravis.

Repetitive nerve stimulation (5/second) was done at the median nerve at the wrist and at the accessory nerve just behind the sternocleidomastoid muscle before and 20 seconds to 5 minutes after tetanic nerve stimulation (1 minute). Since the degree of the neuromuscular block depends on the body temperature these investigations were done successively at skin temperatures of 32 degrees C and 36 degrees C. A comparison of the results obtained revealed the highest rate of pathologic decrement with posttetanic accessory nerve stimulation (32 degrees C = 77%, 36 degrees C = 87%), whereas with posttetanic median nerve stimulation pathological results were obtained in a significantly lower proportion (32 degrees C = 50%, 36 degrees C = 60%). The advantages of the stimulation of the accessory nerve for the detection of partial neuromuscular block are: 1. The superficially located accessory nerve allows for supramaximal stimulation with rather low stimulus intensities (6-20 mA). 2. Since the accessory nerve is mainly a motor nerve, the stimulation is less painful than the stimulation of a mixed nerve. 3. Stimulation of a proximal nerve is more sensitive for detecting a defect in neuromuscular transmission than stimulation of a distal nerve. 4. There is no risk of a pneumothorax and of a traumatic nerve lesion as there is with stimulation of the brachial plexus by needle electrodes.

[Clinical evaluation system (score) of ocular symptoms in myasthenia gravis]. / Klinisches Bewertungssystem (Score) der oculären Symptomatik bei Myasthenia gravis.

A new rating scheme (score) is presented for ocular symptomatology in myasthenia gravis. The score (0-10) combines separate ratings upper eyelid weakness (ptosis) and paralysis of the outer ocular muscles (double vision). It is relatively insensitive to subjective influences and to the rater's experience. It yields replicable values which are especially important for longitudinal studies, for testing new therapeutic strategies and for their statistical validation.

[Myasthenic syndrome during penicillamine treatment (author's transl)]. / Myasthene Syndrome unter Penicillamin-Therapie.

The clinical and electrophysiological findings in 2 men who had developed a myasthenic syndrome after taking penicillamine for rheumatoid arthritis will be described. The symptoms began with dysfunction of the eye muscles following a generalised muscle weakness. Course of illness after withdrawal of penicillamine was not uniform. In one of the patients a complete remission occurred within a year. The other became steadily worse and required continuous treatment with cholinesterase inhibitors. Electrophysiological examinations showed neuromuscular blockade, posttetanic exhaustion, posttetanic potentiation was found in one patient only. An immunopharmacological block of acetylcholine receptors induced by penicillamine is discussed from a pathogenetical point of view.

[Chronic recurrent meningoencephalitis simulating limbic encephalitis]. / Chronisch rezidivierende Meningoenzephalitis mit dem klinischen Erscheinungsbild einer limbischen Enzephalitis.

We report on a woman patient who since 1976 has suffered eight episodes of a meningoencephalitis with features of limbic encephalitis. The duration of the individual episodes has varied from 3 weeks to 2 months. Each time recovery has always been complete. Despite numerous cultural and serological examinations of blood and cerebral spinal fluid (CSF), no infectious agent has been detected. The etiology and entity of this illness are still unclear. To our knowledge such a clinical course has never been reported.

Normal sensory conduction in the saphenous nerve in man.

Measurements of the sensory conduction velocity and the parameters of nerve action potentials in the saphenous nerve offer many advantages, compared with measurements in other nerves of the leg, regarding accuracy and the time required to complete the investigations. Therefore, the electroneurographical examination of the saphenous nerve is recommended in the early diagnosis of polyneuropathies and is indispensable in the exact diagnosis of proximal neuropathies and lesions of the femoral nerve. In the present study we indicate the proximal and distal segments of the saphenous nerve and illustrate the nerve action potentials from 70 normal subjects.

[Spontaneous oral dyskinesia. Successful treatment with tetrabenazine (author's transl)]. / Spontane orale Dyskinesien. Erfolgreiche Therapie mit Tetrabenazin (Nitoman).

Tetrabenazine (50-150 mg/day) was a moderate to excellent efficacy in each of six patients with severe spontaneous oral dyskinesia. Slight akinesia, rigidity, and transient disorientation were occasional side effects that could easily be controlled and were tolerated by the patient in view of the lasting amelioration of this debilitating symptom. When tetrabenazine was administered for blepharospasm, only two of six cases showed partial improvement with more severe side effects.

[Hypokalemic periodic paralysis provoked by "Ambene"]. / Hypokaliämische periodische Lähmung provoziert durch "Ambene".

The case of a 42-year-old man is reported, who on four occasions developed a hypokalaemic periodic paralysis after an intramuscular injection of "Ambene". The detailed examination of this patient shows, that it is the primary, autosomal dominant inherited form of hypokalaemic periodic paralysis, and not the secondary form, which is caused by a renal or gastrointestinal loss of potassium. Clinical and electrophysiological, as well as histopathological and electron microscopic findings are presented, showing the typical vacuolar myopathy with submicroscopic tubular structures. In the literature there is evidence for an increased sensitivity of the muscle membrane to insulin with an increased potassium-shift inside the cell in hypokalaemic periodic paralysis. "Ambene" is a combination, which contains amongst other substances dexamethasone and the local anaesthetic drug lidocain. In the present case the paresis was possibly caused by a combined effect of dexamethasone with a consequent hyperglycaemia and lidocain with a change in the excitability of the muscle membrane. The pathophysiological mechanism of hypokalaemic periodic paralysis is discussed in terms of the release by the combination of these two drugs. It has not previously been reported that "Ambene" can provoke a hypokalaemic periodic paralysis. This is a severe side effect because of the resulting cardiac and respiratory problems.

[Serum levels of pyridostigmine in myasthenia gravis: methods and clinical significance]. / Serumspiegel von Pyridostigmin bei Myasthenia gravis: Methoden und klinische Bedeutung.

Correlation studies on patients with myasthenia gravis are reported in which clinical assessment of fatigue and neurophysiological findings are compared to blood levels of pyridostigmine. Measurements using a high-pressure liquid chromatography method (HPLC), give reproducible results. The levels of pyridostigmine in the serum or plasma of healthy controls and of patients show no essential differences. Components of coffee, tea, chocolate and cigarettes can markedly disturb the chromatography by adding additional peaks, so that interpretation becomes difficult or impossible. Blood levels can be measured approximately one hour after oral intake of 60 mg pyridostigmine. Concentrations rise for two to four hours and then decline exponentially. The half-life of pyridostigmine was between 156 and 210 minutes. Despite identical oral dosages, the concentration differed intraindividually and interindividually among patients. While the blood level does not reach its maximum value for 1-1 1/2 to 3 hours, the maximum clinical and neurophysiological effect of pyridostigmine appears 30-60 minutes after ingestion. Variable distribution of cholinesterase inhibitors over the different compartments (blood, synaptic region) is assumed to cause this temporal lag. If the total amount of pyridostigmine is divided into 4-5 doses, the concentration profiles over the course of a day are relatively stable. There is no significant correlation between the variations in blood level throughout one day, and changes in myasthenic symptomatology. Effects of pyridostigmine can be measured at levels as low as 5 ng/ml; at levels above 40 ng/ml further improvement can be detected only rarely. Blood levels were lower if corticosteroids were administered simultaneously; azathioprine had no influence on blood levels. Blood levels assays allow better differentiation of cholinergic and myasthenic crises and the identification of disturbed absorption and interactions with other medications.

Thymectomy in myasthenia with pure ocular symptoms.

Eighteen patients with exclusively ocular symptoms of myasthenia were thymectomised. Suspected thymoma, resistance to pyridostigmine therapy or relapse following immunosuppressive therapy were taken as indications for surgery. The mean preoperative observation period before operation was 40 months, and after operation was 26 months. There was no operative or postoperative morbidity or mortality. Histological thymic abnormalities were found in all patients (in one case, thymoma; in four, persistent thymus; in 13, thymic hyperplasia). The histological abnormalities were identical to those found in generalised myasthenia. This included the distribution of T-cell subtypes as identified by use of monoclonal antibodies. The severity of ocular symptoms was rated using a score developed for this purpose. The score progressively declined after surgery to an average of 70% of its initial amount in 80% of patients. Full remission occurred in three cases. No patient developed generalized myasthenia. Antibody titres against acetylcholine receptors if elevated preoperatively also dropped following surgery, with one exception. Clear criteria for the expected therapeutic success of thymectomy could not be identified. Based on our results, and on the assumed significance of the thymus gland for pathogenesis, thymectomy should be considered in patients with pure ocular symptoms.

[Antibody-controlled cytostatic therapy of malignant thymoma with concomitant myasthenia gravis]. / Antikörperkontrollierte zytostatische Therapie des malignen Thymoms bei begleitender Myasthenia gravis.

In a 46-year-old female patient with malignant thymoma and concomitant myasthenia gravis relapse with gravitational metastases occurred 6 1/2 years after the first operation. Metastases could be removed surgically only partially and were subsequently irradiated with 50 Gy. After 3 1/2 years renewed metastatic growth occurred. Until then the concomitant myasthenia had been stable during treatment with pyridostigmine and azathioprin and intermittent prednisone; acetylcholine receptor antibody titres had remained largely stable. Combined cytostatic treatment with vincristine, cyclophosphamide, prednisone and doxorubicin or cisplatin led to regression of metastases during the observation period of 1 1/2 years and at the same time to stabilisation of the myasthenia. Acetylcholine receptor antibody titres decreased and this was roughly paralleled by clinical improvement. Whereas there is no obvious correlation of antibodies against acetylcholine-receptor protein and tendency of tumour growth there is good agreement with the course of the accompanying myasthenia.

[Correlation of acetylcholine receptor antibodies and clinical severity of myasthenia gravis in combined immunosuppressive therapy]. / Korrelation von Acetylcholin-Receptor-Antikörpern und klinischem Schweregrad der Myasthenia gravis unter kombinierter immunsuppressiver Therapie.

The correlation between the severity of symptoms in myasthenia gravis (score) and the level of acetylcholine receptor-antibodies (ACHR-Ab) was studied in 24 patients treated with immunosuppressive therapy. This correlation was significant in every case regardless of whether or not thymectomy was performed in addition. It was demonstrated by means of a long-term follow up study, that a change in ACHR-Ab preceeds the corresponding change in score by 2-4 months in 80% of our patients. Measurements of ACHR-Ab ease the management of the therapy with immunosuppressants and make it safer. This is particularly true prior to and after termination of the treatment. A change in ACHR-Ab level by more than 20% indicates a change in score.

[The ultimate electromyographic patterns in reinnervated muscle (author's transl)]. / Elektromyographische Spätbefunde nach Reinnervation

We investigated 59 patients in later stages after section and suture (n =23) or transplantation (n = 36) of the ulnar or median nerve. The most typical change in electromyographic pattern consists in a markedly increase of mean amplitude, due to an increased number and concentration of muslce fibers in the reconstituted motor-units. The mean duration and the incidence of polyphasic potentials are only slightly increased, indicating a nearly synchronous excitement of the different muscle fibers of the various motor-units. In no case there is a complete recovery; the mean amplitude of evoked potentials in reinnervated muscles varied from 32% in poor-, to 62% in satisfactory reinnervation, compared with the corresponding normal muscle in the opposite hand.