This paper is a review of the causes of intermittent monocular blindness. The nature of cholesterol and platelet retinal emboli is discussed. Their sources, the frequency with which they may cause transient or fixed blindness and the association between these emboli and pathology of the major cerebral vessels and other organs is discussed.

Consideration is given to the equally important abnormalities of platelet behavior and to some of the physiology of retinal blood flow and non-embolic blindness.

The current treatment of this symptom may be anticoagulation, surgical correction of a stenotic artery or both. The effect of treatment is unpredictable and in some situations the rationale is suspect.

This review may provide a summary on which to base future studies of the effectiveness of various therapeutic agents.

On the basis of the information presented in this review, it is difficult to reach any firm decision regarding the role of cyclic AMP (or cyclic GMP) in synaptic transmission in the brain. While it is clear that cyclic nucleotide levels can be altered by the exposure of neural tissues to various neurotransmitters, it would be premature to claim that these nucleotides are, or are not, essential to the transmission process in the pre- or postsynaptic components of the synapse. In future experiments with cyclic AMP it will be necessary to consider more critically whether the extracellularly applied nucleotide merely provides a source of adenosine and is thus activating an extracellularly located adenosine receptor, or whether it is actually reaching the hypothetical sites at which it might act as a second messenger. The application of cyclic AMP by intracellular injection techniques should minimize this particular problem, although possibly at the expense of new difficulties. Prior blockade of the adenosine receptor with agents such as theophylline or adenine xylofuranoside may also assist in the categorization of responses to extracellularly applied cyclic AMP as being a result either of activation of the adenosine receptor or of some other mechanism. Ultimately, the development of highly specific inhibitors for adenylate cyclase should provide a firm basis from which to draw conclusions about the role of cyclic AMP in synaptic transmission. Similar considerations apply to the actions of cyclic GMP and the role of its synthesizing enzyme, guanylale cyclase.

The use of phosphodiesterase inhibitors in studies on cyclic nucleotides must also be approached with caution. The diverse actions of many of these compounds, which include calcium mobilization and block of adenosine uptake, could account for many of the results that have been reported in the literature.

Haloperidol (0.25 mglkg i.m.) was injected daily for 6 months in six normal monkeys. Over a 24 hour period, the following symptoms could he observed: akathisia, circling, akinesia, choreoathetoid and dystonic movements, oro-facial dyskinesias and postural tremor with or without harmaline. Six months after cessation of haloperidol, harmaline-induced postural tremor could still be observed in all animals and oro-facial abnormal movements, in one monkey. The neuropathologic study of the experimental material did not disclose any alteration of the central nervous system.

Morphological speech zone asymmetry in man cannot be due to environmental or developmental factors after birth. The functional implication of such a finding is not yet clear. Morphological asymmetry of the human brain is paralleled by electrophysiological evidence of cerebral hemispheric asymmetries. The results of our analysis of 50 infants suggest that clear occipital-temporal coherency asymmetry similar, but not identical to the adult pattern, also exists at or near birth. These asymmetries are generated by stimuli with no verbal content and in infants who presumably have no or an undeveloped capability for language. It is suggested that language is only a part of much more fundamental asymmetries which include the processing of auditory and visual information. Our results, and those of others, are consistent with the assumption that the left hemisphere is more able to relate stimuli to past experience, either short or long-term, while the right hemisphere is more able to process stimuli which are not easily identifiable or referable. These capabilities would not be based on language, and hence would be expected to develop independently and possibly before speech. The demonstration that reversing electrophysiological asymmetries can be generated with non-speech stimuli in the visual and auditory modalities, and in neonates, supports such an assumption.

A 76-year-old male with a severely deforming rheumatoid arthritis, eosinophilic!, polymyositis, and episcleritis developed a transient tonic pupil. The episcleritis, and a muscle biopsy revealing an occlusive arteritis with eosinophilia, suggest that a widespread rheumatoid arteritis caused a reversible ischemic insult to the ciliary ganglion and thus created a transient denervation of the pupil.

The clinical and histological features of two cases of giant cell tumor of the sphenoid bone are described. Both presented with similar symptoms and signs, comparable to previously described cases. The problems in histological differential diagnosis are discussed and radiotherapy as the treatment of choice is suggested.