School closure may be effective in reducing transmission of respiratory viruses in the community.

Proposed measures to contain pandemic influenza include school closure, although the effectiveness of this has not been investigated. We examined the effect of a nationwide elementary school strike in Israel in 2000 on the incidence of influenza-like illness. In this historical observational study of 1.7 million members of a preferred provider organization, we analysed diagnoses from primary-care visits during the winter months in 1998-2002. We calculated the weekly ratio of influenza-like diagnoses to non-respiratory diagnoses, and fitted regression models for school-aged children, children's household members, and all other individuals aged >12 years. For each population the steepest drop in the ratio of influenza-like diagnoses to non-respiratory diagnoses occurred in the strike year 2 weeks after the start of the strike. The changes in the weekly ratio of influenza-like diagnoses to non-respiratory diagnoses were statistically significant (P=0.0074) for school children for the strike year compared to other years. A smaller decrease was also seen for the adults with no school-aged children in 1999 (P=0.037). The Chanukah holiday had a negative impact on the ratio for school-aged children in 1998, 1999 and 2001 (P=0.008, 0.006 and 0.045, respectively) and was statistically significant for both adult groups in 1999 and for adults with no school-aged children in 2001. School closure should be considered part of the containment strategy in an influenza pandemic.

Mandatory computer field for blood pressure measurement improves screening.

METHODS: We evaluated the effectiveness of a compulsory data field in a computerized medical record (CMR) in improving blood pressure (BP) screening. RESULTS: The proportion of study patients who had their BP measured increased from 40.6% to 58.5% (P < 0.001) after the intervention. After adjusting for age, gender and number of visits, patients were 73% more likely to have their BP recorded after the introduction of the compulsory field.

Production of glucose-fructose oxidoreductase and ethanol by Zymomonas mobilis ATCC 29191 in medium containing corn steep liquor as a source of vitamins.

Different concentrations of corn steep liquor (CSL) were tested in the cultivation of Zymomonas mobilis. Cell growth, ethanol production, and the formation of glucose-fructose oxidoreductase (GFOR) and glucono-delta-lactonase (GL), the enzymes responsible for the bio-production of gluconic acid and sorbitol, were examined. The cell yields using 25 g CSL l(-1) and 40 g CSL l(-1) (Y(X,S) approximately 0.031 g g(-1)) were close to that obtained with 5 g yeast extract (YE) l(-1). With 5 g CSL l(-1) and 15 g CSL l(-1), the nutritional limitation led to smaller Y(X/S). Using 100 g CSL l(-1) produced an inhibitory effect on cell growth. Similar ethanol yields (92-95%) were calculated for each concentration of CSL and also for YE medium. The highest specific GFOR/GL activities (13.2-13.5 U g(-1) dry cell) were reached with 25 g CSL l(-1) and 40 g CSL l(-1), values comparable to that achieved with 5 g YE l(-1). The results confirm that CSL is an effective and cheap supplement for Z. mobilis medium, increasing the economic potential of a large-scale bio-production of sorbitol and gluconic acid by untreated Z. mobilis cells. The economic feasibility of the process is discussed.

Antibiotic inhibition of RNA catalysis: neomycin B binds to the catalytic core of the td group I intron displacing essential metal ions.

The aminoglycoside antibiotic neomycin B induces misreading of the genetic code during translation and inhibits several ribozymes. The self-splicing group I intron derived from the T4 phage thymidylate synthase (td) gene is one of these. Here we report how neomycin B binds to the intron RNA inhibiting splicing in vitro. Footprinting experiments identified two major regions of protection by neomycin B: one in the internal loop between the stems P4 and P5 and the other in the catalytic core close to the G-binding site. Mutational analyses defined the latter as the inhibitory site. Splicing inhibition is strongly dependent on pH and Mg2+ concentration, suggesting electrostatic interactions and competition with divalent metal ions. Fe2+-induced hydroxyl radical (Fe-OH.) cleavage of the RNA backbone was used to monitor neomycin-mediated changes in the proximity of the metal ions. Neomycin B protected several positions in the catalytic core from Fe-OH. cleavage, suggesting that metal ions are displaced in the presence of the antibiotic. Mutation of the bulged nucleotide in the P7 stem, a position which is strongly protected by neomycin B from Fe-OH. cleavage and which has been proposed to be involved in binding an essential metal ion, renders splicing resistant to neomycin. These results allowed the docking of neomycin to the core of the group I intron in the 3D model.

City size effects, trends, and policies.

As cities increase in size, so do wage rates for the same work. There is evidence that the wage differential is persistent and stable over time, which suggests that the differential does not arise from a lack of adjustment that is in process of correction. Indeed, there is an inverse relation between size and growth rate. Large metropolitan areas with high wage rates have been losing population in recent years, which is hardly a sign that their higher wage rates are temporary inducements to workers to move into those cities. It is much more plausible that the differential is a more-orless permanent money payment that compensates urban residents for costs they bear as population size increases. This argument does not deny that there are nonwage benefits as well as costs of city size, that city size effects may vary between individuals and groups, or that there may be scope for improved policy on population distribution. Nonetheless, the benefits of size seem to be outweighed by the costs; all types and groups of people generally can and do move about until alternative locations are less attractive than their current location; and solutions to population distribution problems will often emerge as byproducts to the solutions of more basic problems.