Histological alterations in male A/J mice following nose-only exposure to tobacco smoke.

The incidence and multiplicity of grossly observed and microscopic lesions of the respiratory tract of A/J mice exposed nose-only to mainstream smoke (50, 200, or 400 mg total particulate matter/m3 from 2R4F cigarettes) was compared to those of filtered air controls. Animals were necropsied at the end of exposure (5 mo) or following 4 or 7 mo of recovery. Lungs were visually inspected for tumors at all necropsies and examined histopathologically at 9 and 12 mo. At 5 mo no tumors were recorded. No significant elevations in tumor incidence or multiplicity were recorded although at 9 mo multiplicity was elevated in the mid-exposure group (0.90 versus 0.55 tumors per animal for controls). At 12 mo, multiplicity was increased over the 9-mo necropsy at all exposures except 200 mg/m3; however, there were no dose-related trends in multiplicity or incidence. Histopathological alterations included hyperplasia, metaplasia, and inflammation of the nose and larynx and proliferative lesions of the lungs. At 9 mo, the multiplicity of focal lung lesions was 1.4 per animal in controls but averaged 1.0 among smoke-exposed groups. There was an inverse relation (p < .059) between smoke concentration and the percentage of hyperplastic lesions at 9 mo. At 12 mo the high-exposure group had slightly increased multiplicity of 2.3 lesions compared with 1.6 among controls, while the percentage of hyperplasic lesions was similar between groups. Nose-only inhalation of mainstream tobacco smoke resulted in chronic inflammatory changes of the respiratory tract yet failed to produce statistically significant changes in tumor incidence or multiplicity.

Complex data produce better characters.

Two studies were conducted to explore the use of complex data in character description and hybrid identification. In order to determine if complex data allow the production of better characters, eight groups of plant systematists were given two classes of drawings of plant parts, and asked to divide them into character states (clusters) in two separate experiments. The first class of drawings consisted only of cotyledons. The second class consisted of triplets of drawings: a cotyledon, seedling leaf, and inflorescence bract. The triplets were used to simulate complex data such as might be garnered by looking at a plant. Each experiment resulted in four characters (groups of clusters), one for each group of systematists. Visual and statistical analysis of the data showed that the systematists were able to produce smaller, more precisely defined character states using the more complex drawings. The character states created with the complex drawings also were more consistent across systematists, and agreed more closely with an independent assessment of phylogeny. To investigate the utility of complex data in an applied task, four observers rated 250 hybrids of Dubautia ciliolata X arborea based on the overall form (Gestalt) of the plants, and took measurements of a number of features of the same plants. A composite score of the measurements was created using principal components analysis. The correlation between the scores on the first principal component and the Gestalt ratings was computed. The Gestalt ratings and PC scores were significantly correlated, demonstrating that assessments of overall similarity can be as useful as more conventional approaches in determining the hybrid status of plants.

Atypical herpetic endotheliitis.

BACKGROUND: Three patients ranging in age from 26 to 40 years presented with unilateral posterior stromal lesions with diffuse stromal edema. There was no history of prior surgery, trauma, infectious disease, dystrophy or exposure to noxious agents. Only one patient had signs of anterior chamber reaction and none of the patients showed any sign of epithelial involvement or of associated blood vessels or scarring. All three patients presented with features atypical of herpetic disease, such as lack of epithelial involvement and posterior stromal opacification. They also demonstrated many of the typical characteristics of herpetic disease, however, and thus were diagnosed as having herpetic endotheliitis. RESULTS: All three patients were treated with a regimen of antiviral agents and corticosteroids. Two patients improved, although the time frame differed in each. One patient subjectively improved, then worsened 1 month later after discontinuing treatment on her own. She was lost to subsequent follow-up. CONCLUSIONS: Young patients presenting with unilateral posterior stromal opacification and stromal edema in the absence of epithelial involvement are likely to have endotheliitis of herpetic origin.

The differential diagnosis of visual disorders in patients presenting with marked symptoms but with no observable ocular abnormality.

A differential diagnosis of nine conditions which sometimes produce distressing symptoms without overt signs is presented. Sophisticated tests, especially electrodiagnostic ones, can aid the optometrist in making the correct decision. The selected procedures and the expected results are summarized in a table. The conditions reviewed are Stargardt's macular degeneration, Leber's congenital amaurosis, albinism, foveal hypoplasia, retinitis pigmentosa, retrobulbar neuritis, amblyopia, and problems of psychogenic origin.

Electro-oculography, dark adaptometry, and laser interferometry.

This paper discusses the basic concepts of electrooculography (E.O.G.), dark adaptometry, and laser interferometry. Included is the clinical relevance of each procedure.