Immunohistochemical analysis of two strains of lion (Panthera leo)-adapted canine distemper virus in ferrets (Mustela putorius furo).

Canine distemper virus (CDV) caused epizootics in lions (Panthera leo) in Tanzania's Serengeti National Park in 1994 and in captive lions and other Panthera spp. in the USA in 1991-1992. In this study, immunohistochemistry was used to compare viral distribution in tissues collected from ferrets (Mustela putorius furo) inoculated with one of the two lion-derived CDV isolates, either from Serengeti (A94-11/13) or from California (A92-27/20). The California isolate resulted in severe morbidity in all nine ferrets, whereas the Serengeti isolate resulted in severe morbidity in five of the nine ferrets. A slightly higher proportion of infected cells was found in many tissues in the Serengeti isolate-inoculated ferrets. These findings indicate that the pathogenicity of the California isolate is not directly related to the number of infected cells.

Usefulness of electron beam tomography to detect progression of coronary and aortic calcium in middle-aged women.

Electron beam tomography (EBT) permits the noninvasive quantification of coronary and aortic calcium as a marker of atherosclerosis. Coronary and aortic calcium are strongly related to premenopausal cardiovascular risk factors in middle-aged women. This report evaluates changes in coronary and aortic calcium over an average of 18 months in 80 women. Measurement variation over time and between readings is also evaluated in these women who were followed through the menopausal transition. Eight years after menopause, 80 women (average age 63 years) underwent serial EBT of the coronary arteries and aorta separated by 18 months. Calcium scores were based on the number and density of calcific deposits. Duplicate readings were obtained to evaluate the effect of reading variation on calcium scores. At baseline, the median calcium score was 0 in the coronary arteries and 58 in the aorta. Average change in coronary (+11) and aortic (+112) calcium were significantly different from zero (p < 0.001). Reading variability did not contribute significantly to the variation in calcium scores. Extent of calcium in the coronary arteries was associated with progression of calcium in the aorta (p = 0.013). Both coronary and aortic calcium were significantly associated with premenopausal cardiovascular risk factors. Thus, progression of coronary and aortic calcium using EBT can be observed over a short time in healthy middle- aged women.

A novel intermediate filament-associated protein: further characterization of the G.3.5 antigen.

Several novel intermediate filament-associated proteins (IFAPs) have been discovered using hybridoma technology on multiple sclerosis plaque tissue. One of these, designated the G.3.5 antigen, is a desmin-binding IFAP in skeletal and cardiac muscle. It has been suggested that because of sequence similarities to alpha-actinin the G.3.5 antigen is an alpha-actinin-like protein which may cross-link actin and intermediate filaments in the cytoskeleton. In this study, it is reported that (1) the G.3.5 antigen is present in hepatocytes in addition to the previously described astrocytes, skeletal and cardiac myocytes, fibroblasts, and several other non-nervous tissues; (2) in myocytes and hepatocytes, the G.3.5 and alpha-actinins do not co-localize; (3) by transmission electron microscopy the G.3.5 antigen appears to be a rod-shaped dimer similar to alpha-actinin; (4) isolation of the G.3.5 antigen does not simultaneously isolate alpha-actinin; and (5) limited proteolysis of the G.3.5 antigen and alpha-actinin generates dissimilar maps. In binding studies, alpha-actinin cross-links actin but has no effect on desmin; the G.3.5 antigen does not appear to cross-link actin, desmin or mixtures of both under the assay conditions. These results support the hypothesis that the G.3.5 antigen is a novel IFAP related to alpha-actinin, but do not support a role for the antigen as a cross-linker between intermediate filaments and actin.