Conversion of nonfusing mumps virus infections to fusing infections by selective proteolysis of the HN glycoprotein

Mumps virus strains differ in their ability to induce cell fusion following an infection: strains with activeneuraminidase (NANase) fail to cause cell fusion, while strains with less active NANases cause cell fusion. When chymotrypsin is added to infected cells, cell fusion is amplified in a concentration-dependent manner for all mumps virus strains. Virions produced in such infections do not express HN glycoprotein-associated activities. Chymotrypsin treatment of purified mumps virus in vitro results in sequential cleavage into two glycopolypeptides, HNc1 (32K) and HNc2′ (41K), with concomitant loss of hemagglutinating and NANase activities, and infectivity. Further incubation with chymotrypsin causes complete degradation of HNc1 and digestion of HNc2′ to HNc2 (13K–19K). Both HNc2′ and HNc2 contain the [³H]palmitic acid label found in the HN polypeptide, which suggests that these fragments are associated with the viral membrane. Analyses of infected cells and released virions indicate that chymotrypsin acts similarly on HN exposed at the cell surface. Exogenous NAnase does not abolish the protease-augmented cell fusion though it does reduce cell fusion of untreated fusing strain infections. These results confirm that mumps virus HN glycoprotein is critically linked to cell fusion cytopathology and show that cyrptic cell fusion activity in nonfusing strain infections can be unmasked by the proteolytic removal of the HN glycoprotein.     

Ecotropic and dualtropic mink cell focus-inducing murine leukemia viruses can induce a wide spectrum of H-2 controlled lymphoma types

Neonatal infection of C57BL and BALB/c mice by cloned ecotropic and dualtropic mink cell focus-inducing (MCF) murine leukemia viruses (MuLV) induces a wide spectrum of different lymphomas of T, B, and non-T/non-B cell types. Oncogenic dualtropic MCF viruses and poorly oncogenic ecotropic MuLV act synergistically in lymphomagenesis. Within one mouse strain virus-induced T-cell lymphomas arise earlier than B-cell lymphomas after neonatal inoculation of a single-cloned MuLV. The host genetic constitution, notably the H-2 complex has a marked influence on lymphoma type. This H-2 influence can be explained by an H-2-linked difference in penetration of the thymus early in life by oncogenic thymotropic MuLV, which in turn is correlated with, but not necessarily due to the magnitude of the anti-MuLV antibody response.     

Clinical use of biofeedback in rehabilitation

Clinical electromyographic (EMG) biofeedback was an outgrowth of diagnostic electromyography and research on the fine control of motor units. In rehabilitation, EMG biofeedback has gained a firm place in the treatment of upper motor neuron lesions, particularly in retraining muscles and inducing relaxation of spastic muscles of stroke patients. In cerebral palsy and musculoskeletal disturbances, additional feedback transducers (e.g., electrogoniometers, pressure-sensitive and position-sensing devices) are gaining wider use. Spasmodic torticollis has proved to be particularly suitable for behavioral methods of treatment, including EMG feedback.     

Stimulus range influences intensity and hedonic ratings of flavour

Five concentrations of an artificial orange drink were presented for sensory evaluation in three overlapping concentration ranges. Three sensory panels, each of 30 subjects, rated the concentrations for intensity of flavour (intensity scale), relation to ideal flavour intensity (ideal-point scale), and pleasantness (hedonic scale). Except for the two extreme concentrations, neither of which was presented in more than one range, in all three response tasks the mean rating for a given concentration varied with the concentration range in which it was presented. However, the mean ratings showed good correspondence across response tasks (e.g. the concentration perceived as "moderately sweet" on the intensity scale was perceived as "just right" on the ideal-point scale and of maximal pleasantness on the hedonic scale), suggesting a link between the intensity and hedonic dimensions of sensory experience.     

Balloon embolization to occlude a Blalock-Taussig shunt

Balloon embolization was used to successfully occlude a large residual Blalock-Taussig shunt. The use of an "upstream" nondetachable balloon catheter to reduce flow and turbulence during final positioning of the detachable balloon may have made the technique safer and more precise.