Observation of the effect of gravity on the motion of antimatter.

Einstein's general theory of relativity from 19151 remains the most successful description of gravitation. From the 1919 solar eclipse2 to the observation of gravitational waves3, the theory has passed many crucial experimental tests. However, the evolving concepts of dark matter and dark energy illustrate that there is much to be learned about the gravitating content of the universe. Singularities in the general theory of relativity and the lack of a quantum theory of gravity suggest that our picture is incomplete. It is thus prudent to explore gravity in exotic physical systems. Antimatter was unknown to Einstein in 1915. Dirac's theory4 appeared in 1928; the positron was observed5 in 1932. There has since been much speculation about gravity and antimatter. The theoretical consensus is that any laboratory mass must be attracted6 by the Earth, although some authors have considered the cosmological consequences if antimatter should be repelled by matter7-10. In the general theory of relativity, the weak equivalence principle (WEP) requires that all masses react identically to gravity, independent of their internal structure. Here we show that antihydrogen atoms, released from magnetic confinement in the ALPHA-g apparatus, behave in a way consistent with gravitational attraction to the Earth. Repulsive 'antigravity' is ruled out in this case. This experiment paves the way for precision studies of the magnitude of the gravitational acceleration between anti-atoms and the Earth to test the WEP.

Respiratory tract infections by Mycoplasma pneumoniae in children: a review of diagnostic and therapeutic measures.

UNLABELLED: This review discusses the current knowledge on laboratory tests and treatment of respiratory tract infections caused by Mycoplasma pneumoniae (MP) in children. MP infection is endemic in most areas of the world. The highest incidence is seen in children aged between 3 and 14 years. Most infections are mild and non-pneumonic. Parapneumonic complications of MP pneumonia are rare. Complications are described affecting the skin, central nervous system, kidneys, heart, muscles and the eyes. To diagnose an acute MP infection in children, a combination of PCR and IgM serology is sensitive and convenient. In both tests it is possible to obtain a result in 1 to 2 days. As a consequence, adequate antibiotic treatment can be prescribed to the child. Macrolides are the first choice in treatment of MP infection in children. CONCLUSION: The most sensitive and rapid test to diagnose a Mycoplasma pneumoniae infection in children is a combination of nasopharyngeal polymerase chain reaction and IgM enzyme immunoassay. The treatment of choice in children is a macrolide.

Efficacy, safety and tolerability of 3 day azithromycin versus 10 day co-amoxiclav in the treatment of children with acute lower respiratory tract infections.

To compare the efficacy, safety and tolerability of a 3 day course of azithromycin with a 10 day course of co-amoxiclav in the treatment of children with acute lower respiratory tract infection (LRTI), 118 patients with community-acquired LRTI were included in a multicentre randomized double-blind, double-dummy study. The diagnosis of LRTI was based on the presence of respiratory signs and symptoms in combination with consolidation on a chest radiograph or clinical evidence of LRTI. Patients received oral azithromycin suspension (10 mg/kg/24 h) or placebo in one dose for 3 days and co-amoxiclav (45/11.25 mg/kg/24 h) or placebo in three doses for 10 days. Of 110 eligible patients, 56 and 54 patients, respectively, were treated with azithromycin or co-amoxiclav. The percentage of patients cured or clinically improved at days 10-13 (primary endpoint) was 91% for azithromycin and 87% for co-amoxiclav. This difference of 4% (90% confidence interval: -6%, +14%) was not statistically significant (P= 0.55). Significantly (P = 0.01) more related adverse events were found in the co-amoxiclav group. This was largely due to a higher percentage (43% versus 19%) of gastrointestinal complaints. A 3 day course of azithromycin (three doses) is as effective in the treatment of LRTI in children as a 10 day course of co-amoxiclav (30 doses). The azithromycin group had fewer adverse events. We conclude that azithromycin is an effective, safe and well-tolerated drug in the treatment of children with LRTI. An additional advantage is the easy administration and short duration of therapy.

Minor acute effect of an inhaled corticosteroid (budesonide) on bronchial hyperresponsiveness to methacholine in children with asthma.

Several studies have shown that long-term administration of inhaled corticosteroid reduces airway hyperresponsiveness. This study was performed in order to exclude an acute effect of inhaled corticosteroid. In a double-blind, randomized, cross-over study, children with asthma, who had never used inhaled or oral corticosteroid, received a single dose of 0.8 mg budesonide or placebo on two separate days, with an interval of at least 48 h. On each test day, baseline forced expiratory volume in one second (FEV1) and methacholine responsiveness (expressed as provocative dose producing a 20% fall in FEV1 (PD20) to methacholine, in doubling dose) were measured. Both measurements were repeated 2 and 5 h after administration of the drug. Twenty children were included in the study. FEV1 showed a mean increase of 1% at 5 h on the budesonide day, and a decrease of 2% on the placebo day (p = 0.01). PD20 increased by 0.1 doubling dose on the budesonide day, and decreased by 0.4 doubling dose on the placebo day. These changes are within the measurement variation (p = 0.06). We conclude that a single dose of 0.8 mg budesonide has a minor effect on methacholine responsiveness 5 h after administration in children with asthma. It is unlikely that such an effect interferes with the interpretation of data collected in long-term studies.