The human exosome: an autoantigenic complex of exoribonucleases in myositis and scleroderma

The anti-PM/Scl autoantibodies are known to characterize a subset of autoimmune patients with myositis, scleroderma (Scl), and the PM/Scl overlap syndrome. The major autoantigens that are recognized by anti-PM/Scl autoantibodies are designated PM/Scl-100 and PM/Scl-75. These autoantigens have been reported to associate into a large complex consisting of 11 to 16 proteins and to play a role in ribosome synthesis. Recently, it was discovered that the PM/Scl complex is the human counterpart of the yeast (Saccharomyces cerevisiae) exosome, which is an RNA-processing complex consisting of 11 3' → 5' exoribonucleases. To date, 10 human exosome components have been identified, although only some of these were studied in more detail. In this review, we discuss some recent advances in the characterization of the PM/Scl complex.     

Efficacy of Removal of Sucrose-Supplemented Interproximal Plaque by Electric Toothbrushes in an In Vitro Model

Electric toothbrushes were evaluated using a model of plaque removal by fluid shear forces. Sucrose supplementation during plaque development did not affect the removal of bacteria from biofilm exposed to low-energy shear but did increase their resistance to high-energy shear. The toothbrush supplying high-energy shear forces removed significantly more viable bacteria.     

Territory size in the moorhen (Gallinula chloropus): An outcome of RHP asymmetry between neighbours

Territory size can be considered as the outcome of contests between an owner and its neighbours for the resource units in the defended area. Variation in territory size could be dependent upon three possible asymmetries: (1) difference in resource holding potential (RHP); (2) difference in resource value to the competitors; and (3) difference in ‘ownership’ status. These possibilities were tested in a 3-year study of moorhens which defend linear territories along ditches in a grazing marsh habitat. Of the three, relative difference in RHP between an owner and its two neighbours provided the best correlation with territory size. There was no relationship between the amount of resources per unit area and territory size nor between the time of establishing a territory and its later size. Heavier moorhens are more likely to win contests in winter flocks and are thought to have a greater RHP. The ratio of the weight of a male territory owner to the weight of both its male neighbours was highly correlated with territory size. Birds with larger territories may gain more potential nesting sites with good cover from predators.     

Effect of melatonin on jet lag after long haul flights.

OBJECTIVE: To determine whether doses of the pineal hormone melatonin alleviate jet lag. DESIGN: Double blind, placebo controlled crossover trial. SETTING: Long haul return flights from Auckland, New Zealand, to London and back. SUBJECTS: Twenty volunteers with experience of transcontinental flights (eight women and 12 men aged 28 to 68). INTERVENTIONS: Melatonin (or placebo) 5 mg three days before flight, during flight, and once a day for three days after arrival. END POINT: Symptoms of jet lag. MEASUREMENTS AND MAIN RESULTS: Visual analogue scale for feelings of jet lag and tiredness; profile of moods states questionnaire for vigour-activity and fatigue-inertia; and retrospective ratings 10 days after arrival of sleep pattern, energy, and daytime tiredness. Feelings of jet lag were less for subjects taking melatonin (mean score 2.15 v 3.4); these subjects took fewer days than the placebo group to establish a normal sleep pattern (2.85 v 4.15), to not feel tired during the day (3.0 v 4.6), and to reach normal energy levels (3.25 v 4.7). Results for fatigue-inertia and vigour-activity were similar. For all subjects jet lag was more severe on the return (westward) than the outward (eastward) journey. CONCLUSIONS: Melatonin can alleviate jet lag and tiredness after long haul flights.     

Total sleep deprivation does not significantly degrade semantic encoding

ABSTRACT

Sleep deprivation impairs performance on cognitive tasks, but it is unclear which cognitive processes it degrades. We administered a semantic matching task with variable stimulus onset asynchrony (SOA) and both speeded and self-paced trial blocks. The task was administered at the baseline and 24 hours later after 30.8 hours of total sleep deprivation (TSD) or matching well-rested control. After sleep deprivation, the 20% slowest response times (RTs) were significantly increased. However, the semantic encoding time component of the RTs remained at baseline level. Thus, the performance impairment induced by sleep deprivation on this task occurred in cognitive processes downstream of semantic encoding.