Modeling the MHC class I pathway by combining predictions of proteasomal cleavage, TAP transport and MHC class I binding.

Epitopes presented by major histocompatibility complex (MHC) class I molecules are selected by a multi-step process. Here we present the first computational prediction of this process based on in vitro experiments characterizing proteasomal cleavage, transport by the transporter associated with antigen processing (TAP) and MHC class I binding. Our novel prediction method for proteasomal cleavages outperforms existing methods when tested on in vitro cleavage data. The analysis of our predictions for a new dataset consisting of 390 endogenously processed MHC class I ligands from cells with known proteasome composition shows that the immunological advantage of switching from constitutive to immunoproteasomes is mainly to suppress the creation of peptides in the cytosol that TAP cannot transport. Furthermore, we show that proteasomes are unlikely to generate MHC class I ligands with a C-terminal lysine residue, suggesting processing of these ligands by a different protease that may be tripeptidyl-peptidase II (TPPII).

Mechanical failures as a contributing cause to motor vehicle accidents South Africa.

Over the past decades motor vehicles became the primary mode of transportation in developing countries. At the same time an improvement in automotive engineering and manufacturing as well as the phenomena of urbanisation have resulted in more vehicles spending more time on the road at higher speeds. Invariably this leads to driving scenarios where safety critical manoeuvres have to be performed that rely on the mechanical condition of the vehicles. In developing countries, where economic realities force the population to make use of older and less reliable vehicles, the risk of accidents caused by some sort of mechanical failure increases. The casualty rate (events causing death and/or serious injuries) for road traffic accidents in South Africa is amongst the highest in the world. This trend has persisted with little variation over the years, despite the efforts of local road safety organisations and research institutes to decrease them. The main goal of this study was to establish the contribution of mechanical failures to motor vehicle accidents, and furthermore, to compare it with international trends. Data obtained from accident response units (ARU) indicate that tyres and brakes were the main contributors to mechanical failures resulting in accidents in the Pretoria region (Gauteng Province). However, the reported percentage of approximately 3% is comparable to similar statistics from developed countries. Detailed information on the condition of road-going vehicles was then collected in this area. The roadside survey (potential mechanical defect tests (PMDT)) indicated that 40% of the vehicles surveyed on the suburban road and 29% of the vehicles surveyed on the highway had mechanical defects that contravened current road and traffic regulations in South Africa and may, therefore, be at risk of causing an accident due to a mechanical failure. In the Minibus (taxi) survey, large irregularities in tyre inflation pressure were identified as a cause of concern. The main conclusion from this work is that tyres and brakes are the two most dominant components that contribute to the mechanical defects causing accidents, with overloading an additional factor to consider. It is important to acknowledge that these three factors can easily be monitored during simple roadside inspections.

Exploratory study of the decongestive effect of Rhinopront syrup in adults and in children with acute rhinitis.

The decongestive effect of Rhinopront syrup was assessed in 18 adults and 18 children with acute rhinitis, by comparison to a matching placebo syrup and to a commercial standard decongestant (Triaminic tablets or drops). The evolution of symptoms following single dose administration of each treatment was estimated both by objective measurements of nasal resistance using bilateral rhinomanometry and by subjective evaluation of nasal congestion and aspect of the mucosa. In children, the treatment was continued over the next 4 days and the global clinical efficacy of the formulations was subjectively evaluated by the parents. In adult patients, a significant decrease in nasal resistance was obtained after a single dose of Rhinopront (15 g). The effect was already important after 0.5 h and reached a minimum of approximately 50% of baseline within 1 to 2 h; the drop in nasal resistance was significantly less intense for Triaminic (p < 0.05; 0.5-1-h period) and for the placebo (p < 0.05; 0.5-2-h period). In children, the scatter of rhinomanometric measurements precluded the observation of any significant within- or between-group differences; however, a significantly lower nasal congestion score was observed for Rhinopront than placebo, between 4 and 10 h after single dose administration (1 g per year of age). The present work suggests that Rhinopront is an effective nasal decongestant in adults and children with acute congestive rhinitis and supports the adequacy of the proposed twice-daily dosing rate.

Daily chromium intake by infants in Belgium.

The chromium content of human breast milk, infant formulae, cow's milk and beikost was measured by graphite furnace atomic absorption spectrometry following different digestion steps. No significant variation in chromium concentration during lactation was found. The mean concentration was 0.18 ng/ml. The daily chromium intake for Belgian infants of 3 months of age using different types of food was estimated. Exclusively breast fed infants consumed 0.1 microgram/day, while for infants fed cow's milk the intake was five times higher. The exclusive use of commercial infant formulas resulted in an intake of 2 up to 10 micrograms chromium a day.

Chromium and selenium levels in commercially available enteral nutrition.

Chromium and selenium contents of thirty-five commercially available enteral feed were determined by atomic-absorption spectrometry after previous wet ashing. Daily chromium intake, based on a 2,000 kcal (8,368 kJ) diet, was below the proposed safe and adequate intake for 78% of the feedings. Hypocaloric diets especially provided extremely low doses of this element. For selenium nearly 80% of the diets provided intakes below the recommended 50 micrograms/day. Selenium concentration was positively correlated with the protein content (p = 0.007), whilst fat content and selenium concentrations showed a significant negative correlation (p = 0.002). No definite correlation could be found between the selenium and chromium content of the food (p greater than 0.1).