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Background. Effective influenza surveillance requires new methods capable of rapid and inexpensive genomic analysis of evolving viral species for pandemic preparedness, to understand the evolution of circulating viral species, and for vaccine strain selection. We have developed one such approach based on previously described broad-range reverse transcription PCR/ electrospray ionization mass spectrometry (RT-PCR/ESI-MS) technology. Methods and Principal Findings. Analysis of base compositions of RT-PCR amplicons from influenza core gene segments (PB1, PB2, PA, M, NS, NP) are used to provide subspecies identification and infer influenza virus H and N subtypes. Using this approach, we detected and correctly identified 92 mammalian and avian influenza isolates, representing 30 different H and N types, including 29 avian H5N1 isolates. Further, direct analysis of 656 human clinical respiratory specimens collected over a seven-year period (1999–2006) showed correct identification of the viral species and subtypes with .97% sensitivity and specificity. Base composition derived clusters inferred from this analysis showed 100% concordance to previously established clades. Ongoing surveillance of samples from the recent influenza virus seasons (2005–2006) showed evidence for emergence and establishment of new genotypes of circulating H3N2 strains worldwide. Mixed viral quasispecies were found in approximately 1% of these recent samples providing a view into viral evolution. Conclusion/Significance. Thus, rapid RT-PCR/ESI-MS analysis can be used to simultaneously identify all species of influenza viruses with clade-level resolution, identify mixed viral populations and monitor global spread and emergence of novel viral genotypes. This high-throughput method promises to become an integral component of influenza surveillance.

Quantitating regional myocardial perfusion has been the much sought-after but still elusive goal of many intensive investigations over the years. Videodensitometry of the variation of myocardial echogenicity in two-dimensional (2-D) echocardiograms as a function of time in conjunction with the injection of a bolus of an ultrasound contrast agent has been used clinically as a tool for a direct assessment of regional myocardial perfusion, despite that the precise relationship between tissue echogenicity observed on an image and the echoes detected by the ultrasonic probe is unknown. A study was undertaken to determine whether ultrasonic backscatter calculated from unprocessed radio frequency (RF) echoes returned from myocardium could be used to quantitate regional myocardium perfusion. A real-time ultrasonic scanner has been modified and interfaced to a microcomputer to acquire RF data at a rate up to 10 frames per second. Preliminary experimental data were obtained from four open-chest dogs following intracoronary injection of a bolus of Albunex® and two dogs following intravenous injection with this modified scanner. On one hand, these results indicate that the integrated backscatter measured from the region of myocardium perfused by the coronary artery where Albunex® is injected and selected for monitoring initially increases, reaches a peak, and then decreases as the contrast agent is washed out and that the magnitude of the peak is approximately linearly proportional to the volume concentration of Albunex® microspheres injected, clearly demonstrating the feasibility of this approach for quantitating region myocardial perfusion. On the other hand, intravenous injections did not result in any appreciable change in myocardial backscatter in the left ventricle although a response could be observed in the left ventricular blood pool.

AlbunexR is an ultrasound contrast agent prepared by sonicating 5% human serum albumin to produce stable, air‐filled, albumin‐coated microspheres. It is an effective ultrasound contrast agent for use during echocardiography and other ultrasound radiological procedures. Current research is directed toward understanding the physics of the interaction of ultrasound with AlbunexR in tissue. A theoretical model describing the dynamics of these bubbles has been developed by assuming a solid elastic shell. The shell (1) supports a strain that counters the effect of surface tension and thus stabilizes the bubble against dissolution; (2) increases the stiffness of the bubble and thus raises the resonance frequency of the bubble significantly; (3) increases the effective damping of the bubble and thus reduces the scattering cross section of the bubble markedly. Experimental measurements of speed of sound, attenuation coefficient, and backscatter coefficient have been made as functions of acoustic frequency and gas ...

Albunex® is an ultrasound contrast agent prepared by sonicating 5% human serum albumin to produce stable, air‐filled, albumin microspheres. It is an effective ultrasound contrast agent for use with echocardiography and other ultrasound radiology procedures. The characteristics of Albunex that are responsible for the clinically observed high echogenicity of Albunex are discussed. Albunex is composed of a high concentration of noncoalescing microspheres (400–500 μ/nl) with a mean diameter of ≈4 μm and a shell thickness of 30–50 nm, as determined by particle analysis, light microscopy, and electron microscopy. Attenuation and backscatter measurements as a function of ultrasonic frequency and amplitude are reported for varying concentration and size distributions of Albunex.

Nascent SH(X 2Πi, v‘=0,1) and SD(X 2Πi, v‘=0,1) rotational state population distributions, spin–orbit state population ratios, and Λ‐doublet state population ratios have been measured following the UV excimer laser photodissociation of H2S (λ=193, 222, and 248 nm) and D2S (λ=193 and 222 nm), respectively. Nascent SH(X 2Πi, v‘=0) rotational state distributions following 193 nm photodissociation of cold H2S in a free jet expansion vs 300 K H2S in a flowing gas cell were essentially the same, indicating that photofragment angular momentum must be originating predominantly in the dissociation event, and not from rotational energy contained in the parent triatom. Laser excitation spectra of SH(X 2Πi, v‘=1) and SD(X 2Πi, v‘=1) have been recorded for the first time. Rotational state distributions for SH(X 2Πi, v‘) and SD(X 2Πi, v‘) are independent of v‘. Λ‐doublet population ratios of the nascent photofragments are essentially unity for all the cases measured. The nascent rotational state distributions are consi...

The response to dietary deprivation in late pregnancy, as compared to the non-pregnant condition, is more rapid and profound in terms of mobilization of fuels frm peripheral tissues as well as hepatic ketogenesis and gluconeogenesis ("accelerated starvation"). We examined the potential role of hepatic insulin and glucagon receptors in mediating these changes by comparing 48-h fasted 18-day pregnant and age-matched nongravid rats. Molar ratios for insulin:glucagon in peripheral and portal blood were significantly higher in the pregnant rats. Insulin binding to purified liver plasma membrane receptors, when appropriately corrected for differences in insulin degradation by the membrane system, was marginally diminished in the pregnant animals. Glucagon binding and adenylate cyclase activation by glucagon was indistinguishable in the two groups of animals. On the basis of portal vein hormone concentrations and the values for receptor binding, liver insulinization relative to glucagonization appears to be unchanged or slightly increased in the fasted pregnant rat compared to the fasted nongravid rat. Thus, it seems unlikely that much of the "accelerated starvation" response in late pregnancy can be ascribed to diminished insulin and/or increased glucagon availability at the hepatocellular level. Instead, it is hypothesized that postreceptor events play the major role in sustaining the intrahepatic realignments of established fasting in late pregnancy.