Gliotic opaque posterior hyaloid membrane separation: report of two cases.

BACKGROUND: To report two cases with idiopathic unilateral diffuse opacification of the posterior hyaloid membrane (PHM) completely separated from the retina, the mechanism of which is possibly due to glial cell proliferation and migration. CASE PRESENTATION: Two Japanese women at age 75 and 84 with no systemic or ocular history developed diffuse opacification in one eye resembling a ground glass sheet almost all over the surface of the PHM, but not within the vitreous gel or fluid. The retinas were funduscopically normal; however, optical coherence tomography demonstrated hyperreflective icicle-like anterior protrusions from the surface of the fovea. The patients received pars plana vitrectomy, resulting in visual improvement. Cell block preparations of the vitreous in one case revealed a cluster of cells immunoreactive for glial fibrillary acidic protein in consistence with gliosis, while denying vitreoretinal lymphoma from lack of atypical cells and vitreous amyloidosis due to no staining for Congo red or direct fast scarlet. The lesions did not recur during follow-up with no new funduscopic abnormalities. CONCLUSIONS: To our knowledge, this is the first to demonstrate such peculiar cases of vitreous opacity with idiopathic and unilateral onset. Histological assessments revealed the possible pathogenesis of gliotic opaque PHM separation to cause its ground-glass-sheet appearance.

Human nasociliary nerve with special reference to its unique parasympathetic cutaneous innervation.

The frontal nerve is characterized by its great content of sympathetic nerve fibers in contrast to cutaneous branches of the maxillary and mandibular nerves. However, we needed to add information about composite fibers of cutaneous branches of the nasociliary nerve. Using cadaveric specimens from 20 donated cadavers (mean age, 85), we performed immunohistochemistry of tyrosine hydroxylase (TH), neuronal nitric oxide synthase (nNOS), and vasoactive intestinal polypeptide (VIP). The nasocilliary nerve contained abundant nNOS-positive fibers in contrast to few TH- and VIP-positive fibers. The short ciliary nerves also contained nNOS-positive fibers, but TH-positive fibers were more numerous than nNOS-positive ones. Parasympathetic innervation to the sweat gland is well known, but the original nerve course seemed not to be demonstrated yet. The present study may be the first report on a skin nerve containing abundant nNOS-positive fibers. The unique parasympathetic contents in the nasocilliary nerve seemed to supply the forehead sweat glands as well as glands in the eyelid and nasal epithelium.

Site-dependent differences in density of sympathetic nerve fibers in muscle-innervating nerves of the human head and neck.

The autonomic nerve supply of skeletal muscle has become a focus of interest because it is closely related to the adaptation of energy metabolism with aging. We have performed an immunohistochemistry study on tyrosine hydroxylase (TH) and neuronal nitric oxide synthase (nNOS) using specimens obtained from ten selected elderly cadavers (mean age 83.3 years) in which we examined muscle-innervating nerves (abbreviated ''muscle-nerves'' hereafter) of ten striated muscles (soleus, infraspinatus, extra-ocular inferior rectus, lateral rectus, superior obliquus, temporalis, orbicularis oculi, posterior cricoarytenoideus, trapezius and genioglossus) and, as a positive control, the submandibular ganglion. We found that the extra-ocular muscles received no or very few TH-positive nerve fibers. Muscle-nerves to the other head and neck muscles contained a few or several TH-positive fibers per section, but their density (proportional area of TH-positive fibers per nerve cross-section) was one-half to one-third of that in nerves to the soleus or infraspinatus. We did not find nNOS-positive fibers in any of these muscle-nerves. In the head and neck muscles, with the exception of those of the tongue, there appeared to be very few TH-positive nerve fibers along the feeding artery. Consequently, the head and neck muscles seemed to receive much fewer sympathetic nerves than limb muscles. There was no evidence that nNOS-positive nerves contributed to vasodilation of feeding arteries in striated muscles. This site-dependent difference in sympathetic innervation would reflect its commitment to muscle activity. However, we did not find any rules determining the density of nerves according to muscle fiber type and the mode of muscle activity.

Qualitative changes in fetal trabecular meshwork fibers at the human iridocorneal angle.

We examined a series of changes that occur in the trabecular meshwork fibers of human eyes during fetal development at 12-30 weeks of gestation. At 12 and 15 weeks, the uveal meshwork was stained black with silver impregnation (indicating the predominance of collagen types III and IV) in the endomysium of the ciliary muscle. At 20 weeks, in combination with Schlemm's canal, a dense fibrous tissue mass corresponding to the trabecular meshwork anlage appeared and was colored black. The anlage was continuous with the corneal endothelium rather than with the ciliary muscle. Until 25 weeks, the trabecular meshwork was identifiable as fragmented fiber bundles that stained red-black, suggesting a mixture of collagen types I, III, and IV. At 30 weeks, half of the ciliary muscle fibers were inserted into the scleral spur and not into the meshwork. Therefore, any contribution of ciliary muscle contraction to the differentiation of the trabecular meshwork would appear to be limited. We hypothesize that an uneven distribution of mechanical stresses in the area of the cornea-sclera junction causes a tear thereby creating Schlemm's canal and is accompanied by a change in the collagen fiber types comprising the meshwork.