Taches de bougie.

BACKGROUND: Posterior segment lesions, including taches de bougie, may be the presenting sign of sarcoidosis. In patients with unrecognized sarcoidosis, taches de bougie may be misinterpreted as the lesions of birdshot chorioretinopathy (BCR) or multifocal choroiditis (MFC). METHODS: In a retrospective study, the authors identified 22 patients with taches de bougie and sarcoidosis. A tissue biopsy showed noncaseating granulomas in 17 patients. All available ophthalmic and medical records of these patients were reviewed. RESULTS: Two patterns of taches de bougie were observed. Sixteen patients (73%) had small, discrete white spots in the inferior or nasal periphery, indistinguishable from the lesions of MFC. In six patients (27%), larger, posterior, pale yellow-orange streaks developed that were identical to the lesions of BCR. Visual prognosis was better with posterior streaks. The chest x-ray was normal in 5 of 16 patients with peripheral spots and in 3 of 6 patients with posterior streaks. Serum angiotensin-converting enzyme was negative in 5 of 14 patients. Gallium scan showed increased hilar uptake in five patients, three of whom had a normal chest x-ray. Human lymphocyte antigen A29 was positive in one of nine patients. CONCLUSIONS: Sarcoidosis should be considered in patients with fundus findings that resemble BCR or MFC. Initial evaluation should include chest x-ray and testing the angiotensin-converting enzyme level. These test results may be negative in patients outside the 20- to 40-year age group for typical sarcoid. Further evaluation with nondirected conjunctival biopsy and whole-body gallium scan may be indicated in certain patients, including (1) those with BCR or MFC with normal chest x-ray and elevated angiotensin-converting enzyme level; (2) patients older than 50 years with MFC; or (3) human lymphocyte antigen A29-negative BCR.

The effects of ablation of visual cortex in neonatal rabbits on the organization of retinothalamic and retinopretectal projections.

Primary visual cortex was ablated unilaterally in neonatal rabbits. Following a survival of 2-4 months, retrograde degeneration of the dorsal lateral geniculate nucleus (LGd) was assessed, and reorganization of retinofugal pathways was studied using methods of anretrograde transport of [3H]proline or of horseradish peroxidase. A complete lesion of primary visual cortex resulted in complete retrograde degeneration of the LGd with no sparing of any class of neurons. The terminations of retinofugal axons in the pretectum and thalamus were compared with those observed in normal animals. No major reorganization of ipsilateral retinofugal projections was observed in either the thalamus and pretectum ipsilateral to the ablated cortex, or in the thalamus and pretectum contralateral to the ablated cortex. However, contralateral retinofugal projections to the thalamus and to the pretectum ipsilateral to the ablated cortex were significantly different from normal. In the thalamus, the projections to the lateral posterior nucleus were expanded in area and increased in density. In the pretectum, the projections to the rostral pretectal areas were greatly increased in area, especially in the region of the olivary pretectal nucleus and posterior pretectal nucleus. However, the density of these projections was not increased relative to normal. Consideration of these results in relation to other published data on the anatomical consequences of neonatal visual cortex lesions, both in mammals which show behavioral sparing following neonatal visual cortex lesions and in mammals which, like the rabbit, show no behavioral sparing, suggests that: (1) behavioral sparing may correlate with patterns of survival or death of neurons in the thalamus and retina; and (2) reorganization of retinofugal pathways is not necessarily associated with behavioral sparing.

Innervation of extraocular muscles in the rabbit.

The innervation of extraocular muscles in the rabbit was studied by using the methods of horseradish peroxidase (HRP) histochemistry, gross dissection, and quantitative morphology. Subdivisions of the oculomotor complex that innervate the superior rectus, inferior rectus, medial rectus, and inferior oblique and levator palpebrae are described, and our results are in agreement with previous accounts of the projections of this nucleus. Our analysis of the innervation of the lateral rectus and retractor bulbi muscles, however, differs from previous descriptions. The axons of approximately 80% of neurons in the abducens nucleus are in the VIth nerve and innervate the lateral rectus muscle, and approximately 15-20% are internuclear neurons both surrounding and intermingling with the motor neurons of the abducens nucleus. The interneurons project to the medial rectus subdivision of the contralateral oculomotor complex via the medial longitudinal fasciculus (MLF). Neurons in both the abducens and the accessory abducens nucleus innervate the retractor bulbi muscles via the VIth nerve. All neurons in the accessory abducens nucleus innervate the retractor bulbi muscles, but gross dissection revealed that the retractor bulbi is also innervated by the IIIrd nerve. The bases for differences between our data and previously published descriptions are discussed. The trochlear nucleus of the rabbit has not been previously studied by methods of axonal transport. The body of the nucleus, its caudal tail, the trajectories of axons entering the trochlear nerve, and soma size distributions are described. The trochlear nucleus contains approximately 900 neurons; most are motoneurons the axons of which travel in the trochlear nerve and decussate in the anterior medullary velum. Approximately 3% of trochlear motor neurons innervate the ipsilateral superior oblique muscle. Their soma size is significantly smaller than that of contralaterally projecting neurons. For comparative purposes, the innervation of extraocular muscles by the trochlear nerve was also investigated in several rodents and carnivores. In all animals studied, the percentage of trochlear neurons innervating the ipsilateral superior oblique muscle was strikingly uniform (2-4%). Gross dissection of the extraocular muscles revealed in the rabbit a muscle, innervated by the trochlear nerve, for which we propose the name "tensor trochleae." In the rabbit, this muscle is innervated by approximately one-third of the trochlear motor neurons.(ABSTRACT TRUNCATED AT 400 WORDS)