Effect of additional cations on the twitching reaction to intracarotid, nonionic contrast media in rabbits

Previous investigations in this laboratory have confirmed the observation of facial muscle twitching during intracarotid injections of nonionic contrast media (CM) in rabbits. The reaction appears to be a locally mediated effect. To further investigate this reaction, cortical electroencephalogram (EEG) and facial electromyogram (EMG) recordings were made from rabbits receiving selective internal carotid artery (ICA) and external carotid artery (ECA) injections of CM. The effects of iopromide and iohexol were compared with and without the addition of sodium (Na) and calcium (Ca) ions at different concentrations. External carotid injections of iopromide also were performed in some animals paralyzed with D-tubocurarine to exclude the possibility that the reaction is due to an effect on peripheral nerves. The addition of between 5 and 20 mM Ca ions to both CM prevented the reaction but while the addition of Na ions (up to 150 mM) to iopromide had some preventative effect, it did not totally abolish the reaction. In those animals paralyzed with D-tubocurarine, the reaction to iopromide, as observed and recorded by EMG, was the same as that occurring in nonparalyzed animals. This finding is consistent with this reaction being independent of the peripheral nervous system.     

A benign gonadal stromal tumor of the testis of spindle fibroblastic type

Non-Leydig cell gonadal stromal tumors of the testis are rare and most are benign. Criteria for determining malignancy are poorly defined. A gonadal stromal tumor of spindle fibroblastic cells presented in a 34 year old male. The patient remains alive and well with no evidence of metastasis 3 years following surgery. Light and electron microscopical features of the tumor are described.     

Intracerebral ganglioglioma.

A case of a rare intracerebral tumour, namely a ganglioglioma, is reported to illustrate the CT and MRI features. The finding of focal thinning of the inner skull vault in association with an adjacent intracerebral mass lesion can aid in the diagnosis of intracerebral ganglioglioma.