Quantitative secondary ion monitoring gas chromatography/mass spectrometry of diethylstilbestrol in bovine liver

A procedure is described for the extraction of diethylstilbestrol (DES) from animal tissue for quantitative capillary gas chromatography/mass spectrometry (GC/MS). The procedure is based upon use of a strong anion exchange polystyrene divinylbenzene resin for sample purification. The recovery of DES from the resin clean up was 88% in the high parts per trillion (ppt) range. Criteria for identification of DES using selected ion monitoring (SIM) GC/MS are presented. Liquid chromatography/mass spectrometry (LC/MS) was used to investigate altered DES cis/trans ratios observed in biological extracts.     

Processes of State Formation in the Inca Heartland (Cuzco, Peru)

This article addresses Inca state formation in the central highlands of Peru. Using ethnohistoric materials and new archaeological survey data from three areas surrounding Cuzco, the capital of the Inca empire, we argue that rapid Inca expansion after C.E. 1400 was made possible by long-term processes of state formation and regional consolidation. From C.E. 1000-1400, a centralized state developed in the Cuzco Valley, extending its direct administrative control over numerous neighboring groups. Less powerful neighboring polities accepted Inca adm nistration early on, perhaps even n tiating Inca patronage. Strong rivals to Inca control maintained their independence, at times depopulating intermediate areas and settling in defensive sites to protect settlements and resources. Finally, groups of intermediate complexity used alliances and violence to align themselves with the strongest regional competitors. Such variability in regional integration strategies reveals how Inca state formation processes influenced later patterns of imperial conquest and administraton. [Keywords: inca, state formation, imperialism, archaeology, ethnicityl     

Cauliflower mosaic virus: Pathways of infection

This short review summarizes what is known, and points out some of the unknown features, about the molecular biology of the natural spread of cauliflower mosaic virus into a susceptible host and its subsequent replication in that host.     

Lack of enantiomeric specificity in the effects of anesthetic steroids on lipid bilayers

The most important target protein for many anesthetics, including volatile and steroid anesthetics, appears to be the type A γ-amino butyric acid receptor (GABA_AR), yet direct binding remains to be demonstrated. Hypotheses of lipid-mediated anesthesia suggest that lipid bilayer properties are changed by anesthetics and that this in turn affects the functions of proteins. While other data could equally well support direct or lipid-mediated action, enantiomeric specificity displayed by some anesthetics is not reflected in their interactions with lipids. In the present study, we studied the effects of two pairs of anesthetic steroid enantiomers on bilayers of several compositions, measuring potentially relevant physical properties. For one of the pairs, allopregnanolone and ent-allopregnanolone, the natural enantiomer is 300% more efficacious as an anesthetic, while for the other, pregnanolone and ent-pregnanolone, there is little difference in anesthetic potency. For each enantiomer pair, we could find no differences. This strongly favors the view that the effects of these anesthetics on lipid bilayers are not relevant for the main features of anesthesia. These steroids also provide tools to distinguish in general the direct binding of steroids to proteins from lipid-mediated effects.