Prolonged administration of antithymocyte serum in mice. II. Histopathological investigation

Prolonged administration of ATS to mice resulted in depletion of small lymphocytes in the thymus-dependent (paracortical) areas of lymph nodes in all mice. Small lymphocyte depletion of the thymus-dependent periarteriolar region of the spleen was present in most mice, although this feature was masked by plasmacytosis in this region in some. Depletion of small lymphocytes in the thymus-dependent areas of Peyer's patches was evident in some of the younger mice. None of these changes in lymphoid organs were seen in control mice, untreated or given NRS. The thymus was unaffected except in some ATS- or NRS-treated mice which were sick and/or old, in which the narrowing of the thymic cortex was attributed to non-specific stress. Plasmacytosis was seen in the medullae of lymph nodes of both ATS- and NRS-treated mice, although it was more intense in the latter. In non-lymphoid organs the most striking changes were seen in the kidneys of mice treated both with ATS and NRS. Complex-type nephritis followed by amyloidosis was seen in a large proportion of mice over 6 months old in both these groups and in these mice amyloid was seen frequently in other organs, including spleen and liver. Tumours occurred in fifty-four ATS-treated mice, but in no other group. Fifty-two of these tumours were attributable to polyoma virus; two other were lymphoblastomas. Reticulum cell hyperplasia was seen in two further mice.

The erythrocyte glutathione reductase activity (E.C. 1.6.4.2) of healthy blood donors

The erythrocyte glutathione reductase activity was measured in 199 healthy blood donors. The normal range was found to be 6.3 to 39.0 IU/10(9) erythrocytes. There was no variation related to either age or sex.

Ocular myasthenia: evaluation of Tensilon tonography and electronystagmography as diagnostic tests

The value of electronystagmography (ENG) and of tonography in monitoring the beneficial effect of edrophonium chloride (Tensilon) on the extraocular muscles in myasthenia gravis has been assessed. Studies were performed on 17 patients with myasthenia gravis and on 18 control subjects, of whom nine had extraocular muscle weakness due to myopathic or neurogenic lesions.Electronystagmography recorded the repetitive following movements of the eyes elicited during optokinetic nystagmus. Neuromuscular fatigue with the subsequent beneficial response to Tensilon was clearly seen in 50% of patients with myasthenia. False positive responses were not seen in control subjects but in many of these, as in the remaining myasthenic patients, the amplitude and rate of nystagmus seen in the ENG was very variable. These difficulties suggest that the ENG is of limited value as a diagnostic test in myasthenia gravis.Tonography, recording the intraocular pressure of the eye continuously over four minutes, was found to be of considerable value. We found that the intraocular pressure fell on average by 1·6 to 1·8 mm Hg over a one minute period in the control recordings but increased by a mean of 1·6 mm Hg in patients with myasthenia, with a peak effect 35 seconds after Tensilon. In only one patient was there a complete failure of response. This patient, and also another woman who showed a less striking response, had severe myasthenia with a fixed ocular weakness. It is suggested that an absence of any increase in tension with Tensilon may be seen in patients with permanent neostigmine-resistant myopathic change. A small false positive response was seen on one occasion only in a patient with a sympathetic nerve lesion.Tensilon tonography, as a simple painless procedure, would appear to be of considerable value in the diagnosis of ocular myasthenia and also as a diagnostic test in the exclusion of myasthenia as a cause of isolated extraocular neuromuscular weakness.