USE OF 99mTc-MERCAPTOACETYLTRIGLYCINE TO EVALUATE RENAL FUNCTION IN HORSES

Ten healthy horses were injected intravenously with 99mTc-MAG3 and the disappearance of radioactivity from the blood was measured. The total body clearance (Cl(B)) and elimination half-life (t1/2(beta)) were 7.9 +/- 1.5 ml/kg/minute and 32.8 +/- 4.1 minutes, respectively. The disappearance of 99mTc-MAG3 from the blood of 2 horses with compromised renal function was also measured. The data suggest that 99mTc-MAG3 is a useful and clinically applicable radiopharmaceutical for measurement of effective renal blood flow in the horse.     

Australian surveillance for avian influenza viruses in wild birds between July 2005 and June 2007

Objective   To identify and gain an understanding of the influenza viruses circulating in wild birds in Australia.
Design   A total of 16,303 swabs and 3782 blood samples were collected and analysed for avian influenza (AI) viruses from 16,420 wild birds in Australia between July 2005 and June 2007. Anseriformes and Charadriiformes were primarily targeted.
Procedures   Cloacal, oropharyngeal and faecal (environmental) swabs were tested using polymerase chain reaction (PCR) for the AI type A matrix gene. Positive samples underwent virus culture and subtyping. Serum samples were analysed using a blocking enzyme-linked immunosorbent assay for influenza A virus nucleoprotein.
Results   No highly pathogenic AI viruses were identified. However, 164 PCR tests were positive for the AI type A matrix gene, 46 of which were identified to subtype. A total of five viruses were isolated, three of which had a corresponding positive PCR and subtype identification (H3N8, H4N6, H7N6). Low pathogenic AI H5 and/or H7 was present in wild birds in New South Wales, Tasmania, Victoria and Western Australia. Antibodies to influenza A were also detected in 15.0% of the birds sampled.
Conclusions   Although low pathogenic AI virus subtypes are currently circulating in Australia, their prevalence is low (1.0% positive PCR). Surveillance activities for AI in wild birds should be continued to provide further epidemiological information about circulating viruses and to identify any changes in subtype prevalence.     

Magnetar-like emission from the young pulsar in Kes 75

We report the detection of magnetar-like x-ray bursts from the young pulsar PSR J1846-0258, at the center of the supernova remnant Kes 75. This pulsar, long thought to be exclusively rotation-powered, has an inferred surface dipolar magnetic field of 4.9 x 10(13) gauss, which is higher than those of the vast majority of rotation-powered pulsars, but lower than those of the approximately 12 previously identified magnetars. The bursts were accompanied by a sudden flux increase and an unprecedented change in timing behavior. These phenomena lower the magnetic and rotational thresholds associated with magnetar-like behavior and suggest that in neutron stars there exists a continuum of magnetic activity that increases with inferred magnetic field strength.     

Polyteny: A Source of Cryptic Speciation among Copepods

A large form of the copepod Pseudocalanus is found in two warm, semi-landlocked fiords in arctic Canada, together with a similar but smaller form attributable to the widespread P. minutus. The large form has the same chromosomne number as P. minutus, but has larger chromosomes and a higher nuclear DNA content. There are suggestions in the literature that other similar polytenic and cryptic species occur among copepods.     

Efficacy of a transmissible gastroenteritis coronavirus with an altered ORF-3 gene.

Serial passage of virulent transmissible gastroenteritis virus through cell culture reduced its virulence in 3-day-old piglets. Intramuscular inoculation of pregnant gilts with 2 doses of this modified-live virus elicited a level of lactogenic immunity that protected their nursing piglets against a lethal dose of challenge virus. Sequence analysis of a 637-bp fragment of the spike gene containing most of the aminopeptidase receptor and the 4 major antigenic sites from the original and the serially passed viruses were nearly identical. Gel analysis revealed that the fragment from the ORF-3 gene of virulent virus was smaller than the corresponding fragment from the serially passed virus. Sequence analysis of the fragment from the passed virus revealed that the sequence between nt 5310 and nt 5434 was replaced by a 636-bp fragment from the polymerase 1A gene. This replacement resulted in the loss of the CTAAACTT leader RNA-binding site and ATG start codon for the ORF-3A gene but it did not affect the ORF-3B gene.     

Population nucleation, intensive agriculture, and environmental degradation: The Cahokia example

Cahokia, the largest pre-European settlement in North America, was situated on the Middle Mississippi River floodplain and flourished for approximately three hundred years from the 10th century AD onward. The site was favorably located from an environmental standpoint, being proximal to a diversity of microhabitats including expanses of open water and marshes from which the essential, renewable fish protein could be procured. More importantly, the largest local zone of soils characterized as optimal for prehistoric hoe cultivation lay immediately to the east. Here, on the floodplain and along its bordering alluvial fans, the large maize outfields were situated, while the multi-crop house gardens were placed within the habitation zone on soils that had often been culturally enriched by prior occupation. As successful as this strategy might have been for small, dispersed populations in such a plentiful environment, nucleation of large numbers of people at Cahokia provided a different adaptive context that ultimately led to ruinous consequences. The seeds for the city's destruction centered anthropogenically produced environmental degradation. Demands on wood resources for fuel and construction were enormous and agricultural field clearance was in forested rather than prairie settings. The resultant watershed deforestation produced greatly increased rates of erosion, runoff, and unseasonable downstream flooding during the summer growing season. The economic and social consequences of declining production and localized crop failures proved disastrous for this city of farmers.