The Mid-Infrared Spectra of Normal Galaxies.

The mid-infrared spectra (2.5-5 and 5.7-11.6 µm) obtained by ISOPHOT reveal the interstellar medium emission from galaxies powered by star formation to be strongly dominated by the aromatic features at 6.2, 7.7, 8.6, and 11.3 µm. Additional emission appears in between the features, and an underlying continuum is clearly evident at 3-5 µm. This continuum would contribute about a third of the luminosity in the 3-13 µm range. The features together carry 5%-30% of the 40-120 µm far-infrared (FIR) luminosity. The relative fluxes in individual features depend very weakly on galaxy parameters such as the far-infrared colors, direct evidence that the emitting particles are not in thermal equilibrium. The dip at 10 µm is unlikely to result from silicate absorption since its shape is invariant among galaxies. The continuum component has a fnu~nu+0.65 shape between 3 and 5 µm and carries 1%-4% of the FIR luminosity; its extrapolation to longer wavelengths falls well below the spectrum in the 6-12 µm range. This continuum component is almost certainly of nonstellar origin and is probably due to fluctuating grains without aromatic features. The spectra reported here typify the integrated emission from the interstellar medium of the majority of star-forming galaxies and could thus be used to obtain redshifts of highly extincted galaxies up to z=3 with SIRTF.

Nanophthalmic sclera. Ultrastructural, histochemical, and biochemical observations.

Scleral tissue from two cases of nanophthalmos was examined by amino acid analysis, light microscopy, histochemistry, and transmission electron microscopy. Perifibrillar aggregates, similar to proteoglycans, were prominent in the nanophthalmic sclera. The sclerae were thicker than normal and the bundles of collagen fibrils were less ordered. The clinical features of vortex vein compression seem causally related to the disordered and thickened sclera, which, in turn, may be caused by dysfunctional proteoglycans, or interaction with the scleral collagen, or both.

Unilateral optic nerve head and choroidal metastases from a bronchial carcinoma.

A 61-year-old man presented with uniocular gradually progressive visual loss, pain in the eye, visual activity of 6/60, markedly constricted visual fields, optic disc edema, retinal pigment epithelial disturbance at the posterior pole, and markedly delayed filling of the choroid on angiography, with a normal fellow eye. He had suffered from recurrent seizures for 15 years, with some evidence of cortical demyelination. Erythrocyte sedimentation rate was elevated. About 5 months after the onset of visual disturbance, evidence of bronchial carcinoma became apparent and he died 6 weeks later. The etiology of his ocular lesions was established only by histopathological evidence of metastases into the optic nerve head and the choroid. Diagnostic problems presented by the ocular findings are discussed.