F-19 MR imaging of glucose metabolism in the rabbit

Noninvasive metabolic magnetic resonance (MR) imaging reflecting glucose metabolism in the aldose-reductase-sorbitol (ARS) pathway was performed in the rabbit head; after administration of the fluorinated glucose analogue 3-fluoro-3-deoxy-D-glucose (3FD-glucose), fluorine-19 images were generated. Images of 3FD-glucose showed significant 3FD-glucose uptake by adipose tissue, indicating its buffering effects in case of excess loads of glucose. Images of 3-fluoro-3-deoxy-D-sorbitol (3FD-sorbitol) demonstrated the spatial distribution of aldose reductase activities and significant sorbitol accumulation in the lens. Images of 3-fluoro-3-deoxy-D-fructose (3FD-fructose) showed preferential uptake of fructose by muscle tissue. The extremely low toxicity of 3FD-glucose indicates promise for its clinical application in metabolic imaging.     

Zur Frage der aggregationsbedingten Aktivierungen von Pockenviren

Zusammenfassung Mit Hilfe von Gruppensynergismus-Diagrammen habenSharp und Mitarbeiter drei aggregationsbedingte Pockenvirus-Aktivierungsphänomene demonstriert: anomale Plaquebildung durch Kaninchenpockenvirus, MultiplizitätsAktivierung von Vacciniavirus und Multiplizitäts-Reaktivierung an vorher partiell inaktivierten Viruspopulationen.Die Basis sämtlicher Gruppensynergismus-Diagramme bildet die von den Autoren als allgemeingültig angenommene Proportionalität der Plaquetiter zu den Mengen kinetisch autonomer oder aktiver Viruseinheiten. Anhand eines einfachen Modelles einer aggregierenden Viruspopulation wird nachgewiesen, daß diese Annahme unhaltbar ist und zu der unrichtigen Interpretation führen muß, niedrig aktive Viruspopulationen würden durch Teilchenaggregierung Steigerungen ihrer biologischen Aktivität erfahren.Die Ursachen der Fehlschlüsse werden untersucht und durch Beispiele erläutert.

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Concerning aggregation dependent activations of poxvirusesI. Erroneous conclusions deduced from group synergism diagrams

Summary With the aid of group synergism diagramsSharp and coworkers have demonstrated three activation phenomena of pox viruses, depending on particle aggregation: anomalous plaque production of rabbitpox virus, multiplicity activation of vaccinia virus and multiplicity reactivation of partially inactivated viruses.The authors' basis for all group synergism diagrams is supposed proportionality between the number of plaques and kinetically autonomous or active virus units. Certain shortcomings inherent in this concept can be shown by using a simple model of an aggregating virus population. It can further be shown that this hypothesis leads to the misinterpretation that an increase in virus activity were caused by particle aggregation.The sources of the errors are investigated and are illustrated by examples.

     

Factors linked to bacterial vaginosis in nonpregnant women

OBJECTIVES: The purposes of this study were to test the hypothesis that vaginal douching is linked to bacterial vaginosis in both symptomatic and asymptomatic women and to identify other demographic, reproductive, and lifestyle factors associated with bacterial vaginosis. METHODS: In this cross-sectional study involving 3 clinic sites, 496 nonpregnant women completed a self-administered questionnaire. Their vaginal smears were assessed and cross-validated for bacterial vaginosis. RESULTS: The prevalence of bacterial vaginosis across clinics ranged from 15% to 30%. In analyses restricted to site 1, adjusted odds ratios (ORs) for bacterial vaginosis remained significant for African American women with 13 or fewer years of education (OR = 5.5, 95% confidence interval [CI] = 2.1, 14.5), hormone use within the past 6 months (OR = 0.5, 95% CI = 0.2, 0.8), and vaginal douching within the past 2 months (OR = 2.9, 95% CI = 1.5, 5.6). CONCLUSIONS: Two lifestyle factors emerge as strongly associated with bacterial vaginosis: systemic contraceptives appear protective, whereas douching is linked to an increase in prevalence. The temporal relationship between douching and bacterial vaginosis needs further clarification.     

Digital beam attenuator technique for compensated chest radiography

The feasibility of producing patient-specific beam attenuators for chest radiography has been investigated using an anthropomorphic phantom and a human volunteer. A low-dose test exposure is digitized, processed, and used to print a small cerium filter, which is placed in the x-ray beam near the collimator. The final radiograph is recorded on film. The technique results in relatively uniform film exposure, so that structures in all regions of the chest are simultaneously displayed with optimal film contrast. The equalized exposure improves image quality in the normally underpenetrated regions and reduces the role of cross-scatter from the lungs. The image is analogous to optical or computer-processed unsharp masking techniques, but the processing is accomplished in the x-ray beam and results in an improved exposure distribution, giving advantages that cannot be achieved with image processing techniques alone.