One hundred consecutive patients with myasthenia gravis (MG) referred between 1985 and 1989 were analysed for epidemiological characteristics, evolution of early signs, delay in diagnosis, yield of diagnostic tests and effects of treatment. The female to male ratio was 1.6:1.0. Sixteen patients had a thymoma. Ocular MG occurred in 14. Associated autoimmune diseases were found in 15 patients. In 34% of the women and 10% of the men the diagnosis was delayed for more than 2 years. In the first 3 months progression was more rapid in men than in women. Anti-acetylcholine receptor antibodies were found in 94% of the patients with generalized MG and in 29% of the ocular patients. The neostigmine or the edrophonium test was positive in 84% of the generalized and in 60% of the ocular patients. Electromyography was diagnostic in 71% of the generalized and in 42% of the ocular patients tested. Thymectomy was performed in 56 patients (12 with thymomas). Fifty-one per cent were treated with one or more immunosuppressive drugs, at any time. After a mean follow-up of 9.6 years after onset remissions had occurred in 43%, considerable improvement in 25%, moderate improvement in 20% and 12% remained unchanged. There were no deaths due to MG. Thirty-six per cent remained dependent on immunosuppressive drugs. Medication-free remission was most frequent (35%) in the early-onset (< 50 years) group. Side-effects of pyridostigmine were noted in 34% of 99 patients, of prednisone in 65% of 49 patients, and of azathioprine in 54% of 28 patients, but these necessitated stopping the drug in only 1%, 10% and 14% respectively.

In myasthenia gravis, loss of acetylcholine receptors at motor end-plates is induced by antireceptor autoantibodies. At end-plates in rats in which myasthenia gravis-like symptoms are induced by chronic treatment with alpha-bungarotoxin, acetylcholine release is increased. Within muscles from such rats there is a strong correlation between the increase of acetylcholine release at an end-plate and the loss of postsynaptic acetylcholine receptors, caused by the toxin. The question is whether upregulation of acetylcholine release is a clinically relevant compensatory mechanism in myasthenia gravis or only a feature of the animal model using alpha-bungarotoxin. We investigated electrophysiologically the in vitro acetylcholine release at end-plates of muscles from patients with myasthenia gravis and rats with experimental autoimmune myasthenia gravis where acetylcholine receptor reduction is caused by autoantibody attack. In both human and rat autoimmune myasthenic muscle, the mean quantal content was considerably increased compared with control levels. At each individual myasthenic end-plate, the increase in quantal content appeared to be correlated with the reduction of the amplitude of the miniature end-plate potential. This finding suggests the existence of an important compensatory mechanism in myasthenia gravis, in which retrograde acting factors (i.e., from muscle fiber to nerve terminal) upregulate acetylcholine release.

Robotic thymectomy in patients with MG is safe and feasible. A neurological benefit and decreased use of steroids can be obtained in the majority of patients. No significant difference in neurological outcome was observed as the result of timing of robot thymectomy after the onset of MG.

Today's health sciences educational programmes have to deal with a growing and changing amount of knowledge. It is becoming increasingly important for students to be able to use and manage knowledge. We suggest incorporating open-book tests in assessment programmes to meet these changes. This view on the use of open-book tests is discussed and the influence on test quality is examined. To cope with the growing amount of medical knowledge, we have divided the body of knowledge into core knowledge, which students must know without need for references, and backup knowledge, which students need to understand and use properly with the help of references if so desired. As a result, all tests consist of a subtest for reproduction and understanding of core knowledge (a closed-book test) and a subtest for the ability to understand and manage backup knowledge (an open-book test). Statistical data from 14 such double-subtest exams for first and second-year students were analyzed for two cohorts (N = 435 and N = 449) with multilevel analysis, in accordance with generalizability theory. The reliability of the open and closed-book sections of the separate tests varied between 0.712 and 0.850. The open-book items reduce reliability somewhat. The estimated disattenuated correlation was 0.960 and 0.937 for cohorts 1 and 2 respectively. It is concluded that the use of open-book items with closed-book items slightly decreases test reliability but the overall index is acceptable. In addition, open and closed-book sections are strongly positively related. Therefore, open-book tests could be helpful in complementing today's assessment programmes.