Galaxy growth in a massive halo in the first billion years of cosmic history.

According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field. Observing these structures during their period of active growth and assembly-the first few hundred million years of the Universe-is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far. Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey. High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe. These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.

Methamphetamine overdose: experience with six cases.

We describe experience with 6 cases of methamphetamine overdose. Because of its low cost, easy availability and longer duration of action compared to cocaine, methamphetamine has become the drug of choice in various communities. Marked change in mental status was observed in all of our patients. One patient had a myocardial infarction that responded well to thrombolytic therapy. Clinicians should be familiar with the medical effects and treatment of acute methamphetamine toxicity.

[Cooperation of veterinarians in legislation in the area of environmental hygiene (Germany and the European Economic Community)]. / Mitwirkung des Tierarztes bei der Rechtssetzung im Bereich der Umwelthygiene (Deutschland und EG).

After a brief exposition of the tasks about the protection against chemical, physical, and biological environmental risks, a demonstration will be given according to deliberations of our law system about the possibilities for veterinarians to cooperate in the legislative branches. A detailed examination on former activities in the fields of pollution and the food-chain are to serve as a model for the future legislative process in Germany with the intention to strive for a harmonization of the in parts independently developed legislative branches. The external harmonization, a long-term objective, is to be found in the form of an uniform environmental law. Veterinarians take a great interest to work in advance for this uniform law in the way they bring new perspectives by cooperating in the fields of environmental hygiene and toxicology for the protection of the environmental media, of species and the food-chain. In conclusion one finds a brief documentation about the impact of the adaptation of law and the process on the EC-level.

Simulation of human pharmacokinetic profiles in mice, and impact on antimicrobial efficacy of netilmicin, ticarcillin and ceftazidime in the peritonitis-septicemia model.

Pharmacokinetic profiles in small animals substantially differ from those observed in man. We hence devised a man adapted animal model to critically assess the impact of such differences on antimicrobial efficacy. We approximated in mice the human pharmacokinetic profiles of netilmicin, ticarcillin and ceftazidime. The CD50 (curative dose for 50% of lethally intra-peritoneally infected animals) against Pseudomonas aeruginosa was comparatively determined for murine versus man-adapted pharmacokinetic profiles. With netilmicin the man-adapted profile was significantly less efficacious than the murine profile. In contrast, a significant superiority of the man-adapted profile was found with the beta-lactam drugs. We conclude that determinations of antimicrobial activity in small animals may yield misleading results in respect to man. Depending on the drug in question, murine pharmacokinetics may lead to overestimation or underestimation of antimicrobial activity. Our findings are of particular importance for the interpretation of studies in small animals comparing different antimicrobial compounds or different dosage regimens.

Antibiotic therapy of infections due to Pseudomonas aeruginosa in normal and granulocytopenic mice: comparison of murine and human pharmacokinetics.

An effort was made to elucidate the limits of drug-activity tests in small animals. Human plasma kinetics of gentamicin, netilmicin, ticarcillin, ceftazidime, and ceftriaxone were approximated in normal and in granulocytopenic mice infected with various strains of Pseudomonas aeruginosa in the thigh muscle or intraperitoneally. The effect of such dosing on bacterial time-kill curves and on survival was compared with the effect of identical amounts of drug given as a single-bolus injection. With beta-lactams, a highly significant superiority of fractionated dosing (simulated human kinetics) over bolus injections (murine plasma kinetics) was demonstrated, whereas with aminoglycosides it was a single-bolus injection that tended to be more active. Thus, when tested in conventional small-animal models, aminoglycoside activity may be overestimated, whereas beta-lactam activity may be underestimated in respect to humans. These differences found in vivo most probably reflect the different pharmacodynamics between aminoglycosides and beta-lactam drugs (time-kill curves, dose-response curves, and postantibiotic effect) similar to those previously observed in vitro.