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Christopher M Bloom,1 Ryan J Post,1 Joshua Mazick,1 Brittany Blumenthal,1 Caroline Doyle,1 Brenna Peters,1 Jeff Dyche,2 D Gene Davenport3 1Providence College, Providence, RI, USA; 2James Madison University, Harrisonburg, VA, USA; 3Saint Louis University, St Louis, MO, USA Abstract: Traditionally, the signaled avoidance (SA) paradigm has been used in an attempt to better understand human phobia. Animal models of this type have been criticized for ineffectively representing phobia. The SA model characterizes phobia as an avoidance behavior by presenting environmental cues, which act as warning signals to an aversive stimulus (ie, shock). Discriminated conditioned punishment (DCP) is an alternative paradigm that characterizes phobia as a choice behavior in which fear serves to punish an otherwise adaptive behavior. The present study quantifies the differences between the paradigms and suggests that DCP offers an alternative paradigm for phobia. Rats trained on either SA or DCP were compared on a number of behavioral variables relevant to human phobia. Results indicate that rats in the DCP paradigm responded significantly earlier to warning signals and were more effective at preventing shocks than rats in the SA paradigm. Implications of this alternative paradigm are discussed. Keywords: animal models, avoidance, fear conditioning, anxiety disorders

Generally injuries that remove or disrupt the endothelial cells lining blood vessels stimulate formation of vascular lesions composed of smooth muscle cells. One of the first events after such endothelial cell disruption is the generation of thrombin at the site of injury. This leads to platelet activation and thrombus formation. Evidence suggests that thrombus formation may stimulate smooth muscle-cell proliferation through the action of any number of factors emanating from the thrombus including platelet- or macrophage-derived factors, platelet-derived growth factor, basic fibroblast growth factor or thrombin. Atherosclerotic plaques continue to grow for many years. The slow indolent process of nondenuding chemical injury of the endothelium and lesion formation may be accelerated periodically by thrombi forming on the lumenal surface at sites of small denuding injuries leading to progressive atherosclerotic disease. Genistein, an isoflavonoid derived from soy products, has been shown to inhibit thrombin formation and platelet activation in vitro in addition to its antigrowth factor activity. Should it have similar actions in vivo, this compound has the potential to affect the progression of atherosclerotic disease by modifying coagulation responses. To assess the potential of genistein as a therapeutic for vascular disease, additional studies will be required to establish its effect on experimental vascular lesion formation. [ABSTRACT FROM AUTHOR]

El Niño events owe their name to their tendency to be locked to the seasonal cycle. A simple explanation is proposed here for the locking of the peak of ENSO's basin-scale warming to the end of the calendar year. The explanation is based on incorporating a seasonally varying coupled ocean--atmosphere instability strength into the delayed oscillator mechanism for the ENSO cycle. It is shown that the seasonally varying amplification of the Rossby and Kelvin ocean waves by the coupled instability forces the events to peak when this amplification is at its minimum strength, at the end of the calendar year. The mechanism is demonstrated using a simple delayed oscillator model and is further analyzed using the Cane--Zebiak model. Being based on the oversimplified delayed oscillator paradigm of ENSO, the proposed mechanism cannot be expected to fully explain the locking of observed events to the end of the year. However, the wave dynamics perspective it offers to approaching the ENSO phase-locking problem may serve as a first step toward a fuller explanation based on more realistic models and additional data analysis. [ABSTRACT FROM AUTHOR]

Vertebral body aplasia or hypoplasia leads to rapidly progressive spinal deformity and neurologic defects when unrecognized in infancy. Four patients with this unusual defect are described. [ABSTRACT FROM AUTHOR]

Abstract Periodic epidemics of malaria are a major public health problem for many sub-Saharan African countries. Populations in epidemic prone areas have a poorly developed immunity to malaria and the disease remains life threatening to all age groups. The impact of epidemics could be minimized by prediction and improved prevention through timely vector control and deployment of appropriate drugs. Malaria Early Warning Systems are advocated as a means of improving the opportunity for preparedness and timely response. Rainfall is one of the major factors triggering epidemics in warm semi-arid and desert-fringe areas. Explosive epidemics often occur in these regions after excessive rains and, where these follow periods of drought and poor food security, can be especially severe. Consequently, rainfall monitoring forms one of the essential elements for the development of integrated Malaria Early Warning Systems for sub-Saharan Africa, as outlined by the World Health Organization. The Roll Back Malaria Technical Resource Network on Prevention and Control of Epidemics recommended that a simple indicator of changes in epidemic risk in regions of marginal transmission, consisting primarily of rainfall anomaly maps, could provide immediate benefit to early warning efforts. In response to these recommendations, the Famine Early Warning Systems Network produced maps that combine information about dekadal rainfall anomalies, and epidemic malaria risk, available via their Africa Data Dissemination Service. These maps were later made available in a format that is directly compatible with HealthMapper, the mapping and surveillance software developed by the WHO's Communicable Disease Surveillance and Response Department. A new monitoring interface has recently been developed at the International Research Institute for Climate Prediction (IRI) that enables the user to gain a more contextual perspective of the current rainfall estimates by comparing them to previous seasons and climatological averages. These resources are available at no cost to the user and are updated on a routine basis.