Altered polyamine levels in skeletal muscle of patients with myasthenia gravis.

Forty patients with myasthenia gravis were tested for polyamine content of the musculus sternothyreoideus removed during thymectomy. Cases with slight muscle alteration were found to show elevated values for all the three polyamines (putrescine, spermidine and spermine) examined with an increased spermidine/spermine ratio. In severe muscular atrophy, however, the high spermidine and spermine levels were accompanied by unchanged putrescine content and spermidine/spermine ratio. Denervational changes in polyamine levels parallel to the degree of muscular damage are useful indicators of the actual grade of muscle atrophy associated with myasthenia gravis. In histologically intact samples, without apparent signs of muscular atrophy the spermidine level and spermidine/spermine ratio were increased in comparison to the control. In addition to being very early signs of denervation, these higher values are possibly the biochemical expression of some adaptive, compensatory hyperfunction of the muscle fibers.

Myasthenia gravis: prognostic significance of clinical data in the prediction of post-thymectomy respiratory crises.

Medical records of 170 patients who had undergone thymectomy for myasthenia gravis were reviewed from the point of view of respiratory disturbances. In the group of patients requiring mechanical ventilation for over 24 hours after operation the incidence of high preoperative cholinesterase inhibitor intake, severe bulbar symptoms and severe myasthenia gravis with anamnestic respiratory crisis and cardiorespiratory disease were much higher than in the group of patients who could have their trachea extubation within 24 hours. The presence of a thymic tumour, patients' age over 50 years and the so-called precrisis have revealed differences between the two groups, while the patient groups were identical in mean age, duration of myasthenia gravis and sex distribution. The above clinical data are recommended to be considered in the evaluation of the need for postoperative mechanical ventilation or extubation and preparation of preventive tracheotomy.

Myasthenia gravis: long-term prognostic value of thymus lactate dehydrogenase isoenzyme pattern of hyperplastic thymus and thymoma.

Lactate dehydrogenase (LDH) isoenzyme pattern and the percent of H-subunit content were determined in the thymus of 62 patients (55 with hyperplasia, 7 with tumours) after thymectomy. An increase in LDH1 relative activity indicates that in the thymus of patients with myasthenia gravis the ratio of mature differentiated thymocytes was higher than in the thymus of control subjects. LDH isoenzyme profiles of thymus tumours were similar to those described in other neoplasms, except that thymomas with apparent predominance of epithelial cells and with minimal lymphocytic reaction exhibited a marked elevation only in LDH2 relative activity, presumably associated with the specific (secretory) function of epithelial cells. The elevation of H-subunit content, a parameter characteristic of both thymic components (lymphoid and epithelial), correlated closely with a poor clinical condition in patients several years after surgery.

Myasthenia gravis: protective effect of ipratropiumbromide (Atrovent) on airways obstruction caused by edrophonium chloride (Tensilon).

The preventive effect of Atrovent Dosier-Aerosol on the airway flow resistance (Raw) caused by Tensilon was studied on 10 patients suffering from myasthenia gravis. Atrovent completely prevented the increase of Raw in 8 cases and considerably decreased it in 2 cases. The measure of the reaction observed may be influenced by the intensity of the cholinergic symptoms occurring on administration of Tensilon as well as by the magnitude of the initial Raw value. No side-effect which may be attributed to the administration of Atrovent could be observed, the substance did not increase the myasthenic symptoms. According to the study, Atrovent is a suitable medicine for the prevention of airway obstruction caused by Tensilon.

[Ultrastructure and classification of epithelial thymomas]. / Az epithelialis thymomák ultrastruktúrája és felosztása.

4 epithelial thymomas out of 36 various types of it were studied electronmicroscopically. The following types were distinguished: clear cell thymoma, dark cell, solid thymoma, lacunar and spindle cell thymoma. These types of thymomas differ not only morphologically, but clinically. Authors suggest, that these tumours take their origin from the star-shaped clear- and dark medullar epithelial cells.

[Myasthenia gravis: epithelial cells of the hyperplastic thymus. Morphometric and ultrastructural study]. / Myasthenia gravis: a hyperplasiás thymus epitheliális sejtjei. Morfometriás és ultrastrukturális tanulmány.

Epithelial cells of hyperplastic thymuses, removed because of myasthenia gravis were studied electronmicroscopically and morphometrically. The correlation between the age of patients and the number of epithelial cells of the thymus is discussed. Various type of epithelial cells are distinguished. Authors believe, that in the pathogenesis of myasthenia gravis beside the presence of lymphoid follicles in the hyperplastic thymus increase of the number of epithelial cells and their activation may take a part.

Myasthenia gravis: the effect of Tensilon on the caloric nystagmus response. Photoelectronystagmographic study.

The nystagmus response evoked by thermic vestibular stimulation on 25 patients with myasthenia gravis and on 10 control persons was investigated using the photoelectronystagmographic method before and after administration of Tensilon. On the basis of 19 nystagmograms (capable of being evaluated) it was found that the test is of diagnostic value when combined with abstinence from drugs, furthermore, it may indicate under- or overtreatment of patients taking drugs. Excluding the drug-resistant, "burned out" cases, a certain correlation may be observed between the magnitude of the reaction evoked by Tensilon and the severity of the clinical condition independent from the existence of ocular symptoms. The advantage of the test, apart from being numerically measurable, is that it can be repeated because of its non-invasive nature causing no physical burden to the patient. Its disadvantage is that it cannot be applied in cases with a pre-existent difference in vestibular tonus - 20% in the material tested.

Myasthenia gravis: lung-function studies without and with edrophonium chloride.

25 myasthenia gravis-afflicted patients (14 crisis-endangered and 11 not endangered) were investigated with respect to their respiratory function and reaction of the respiratory parameters to Tensilon (edrophonium chloride). Results show that the vital capacity and the value of respiratory function parameters, measured under forced conditions, were partly significantly lower than those given as predicted values for healthy individuals. Maximal inspiratory flows indicated the greatest decrease. After intravenously administered Tensilon, the pathologically reduced maximal inspiratory flows increased. This positive effect of Tensilon can mark the alteration of the respiratory muscles and also the undertreatment of the patients. The observation that Tensilon may increase -- with some permanency -- the respiratory flow resistance and may decrease the maximal expiratory flow values, draws attention to the side effect (causing obstruction of the bronchi) of the drug, limiting its therapeutic use for patients in myasthenic crisis, especially in those complicated by obstructive lung disease.

[Ultrastructure of the thymus and neuromuscular junction in myasthenic and non-myasthenic patients]. / A thymus és neuromuscularis junctio finomszerkezete myastheniás és nem myastheniás betegekben.

Ultrastructural changes in 35 neuromuscular junctions taken from myasthenic patients (in 2 cases: hyperplasia of the thymus, in 1 case: epithelial thymoma was present) treated with anticholinesterase during 1--2 years, appeared to be similar to those observed in non-myasthenic patients with lymphoid thymoma (getting no treatment with anticholinesterase). Number of the secretory granules in the epithelial cells of the thymus was in accordance with the severity of the disease. It can be assumed, that in the disturbance of the neuro-muscular transmission of the stimuli the activation of the epithelial cells may play a part.

Myasthenia gravis: mitotic activity of thymus-dependent and blood-lymphocytes.

The thymus and blood lymphocytes of 20 thymectomized patients with myasthenia gravis, including 3 cases of thymoma, have been studied for mitotic activity (spontaneous mitotic activity of native thymocytes, responsiveness of cultured cells to PHA, DNA-polymerase specific activity). The myasthenic thymus gland was found to be the site of a spontaneous DNA-synthesis of similar intensity as the mitotic activity of the thymus in infancy. This was also reflected by the DNA-polymerase activity of the cells. While the thymocyte cultures responded well to PHA stimulation in 50% of the cases, the blood-lymphocytes were found unresponsive. There was a partial correlation between the individual parameters of mitotic activity, but practically none between the mitotic activity and the clinical severity of myasthenia or the histological features of the thymus or of thymoma. Except in the latter cases, a correlation was found between mitotic activity and preoperative immunosuppressive treatment. It is suggested that the T-lymphocytes are not directly involved in the pathomechanism of myasthenia gravis.

Myasthenia gravis: ALG treatment of seriously ill patients.

The authors review the theoretical basis of human antilymphocyte globulin (ALG) and human antihymocyte globulin (ATG) treatment in myasthenia gravis. Ten selected seriously ill myasthenic patients were treated with ALG and/or ATG. Three of the patients improved significantly and a further four moderately, whereas the condition of three patients did not change. ALG therapy is effective in the suppression of cellular immune mechanism, therefore it can be assumed that it exerts its effect in myasthenia gravis by inhibiting thymus hormone stimulation.