Environmentally induced changes in peripheral benzodiazepine receptors are stressor and tissue specific

The stress-induced changes in peripheral benzodiazepine receptors (PBR) can be observed in a number of different tissues, depending upon the nature and chronicity of the aversive experience. In addition, virtually all stress procedures that cause rapid changes in PBR simultaneously increase the physical activity or metabolic rate of the subjects. The present study analyzed the contributions of rapid alterations in activity or metabolic rate with and without aversive stimulation and their subsequent impact on PBR. Mechanically induced increases in activity by forced running stress results in a significant reduction in [3H]Ro 5-4864 binding to PBR in olfactory bulb, opposite to the PBR changes in this tissue following forced cold-water swim stress. Pharmacological induction of increased locomotor activity as well as metabolic rate by d-amphetamine causes a significant increase in cardiac PBR binding, again, opposite to the response typically observed following inescapable shock stress. Finally, administration of the anxiogenic beta-carboline, FG-7142, causes increases in both hippocampus and adrenal gland PBR binding reminiscent of acute noise stress exposure. These experiments demonstrate that increased locomotor activity or metabolic rate alone is not a necessary and sufficient condition for previous stress-induced changes in PBR. Conversely, increased metabolic rate coupled with an aversive stimulus appears to be an important factor for inducing stress-like changes in PBR. This data, coupled with previous reports, suggests that rapid alterations in these sites are stressor and tissue dependent. Finally, we propose that the PBR may be involved in many aspects of the stress response including: a) a blowarning system in adrenal gland, b) participation in stress-induced hypertension via renal PBR, and c) a modulator of stress-induced immunosuppression and subsequent recovery of function or recuperation by actions on immune cells.     

Electrophysiologic observations in the classical form of Pelizaeus-Merzbacher disease

In a 20-year-old patient with the classic form of Pelizaeus-Merzbacher disease, electroencephalograms during wakefulness were moderately diffusely abnormal, and an overnight polygraphic sleep recording showed distorted nonrapid eye movement sleep patterns without vertex sharp waves, K-complexes, spindles, or positive occipital sharp transients. Rapid eye movement sleep could be identified. Cerebral responses evoked by light flashes, clicks, and electric stimulation of the median nerves were abnormal.     

Photoresponse of high resistivity cadmium telluride between room temperature and 400°C

The behavior of CdTe as an infrared photodetector to operate at 400°C over the range between 0.8 and 1.2 μ was studied. It was shown that chlorine-doped CdTe indeed can be prepared to possess signal-to-noise ratios at 400°C of 50:1 at 50 μW/cm² of illumination with a 1 kHz bandwidth. Furthermore, iridium has proven to be a stable contact, and 1000-hr life tests of Ir-contacted CdTe chips in hermetically sealed, gas filled T08 transistor headers showed no significant variations in the signal-to-noise ratios.     

Application of a wide area backup protection expert system toprevent cascading outages

A strategy to prevent cascading outages in power systems is proposed in this paper. The strategy employs wide-area backup protection and artificial intelligence techniques to minimize the impact of a fault on a network. There are two ways in which wide-area backup protection can prevent cascading trips leading to a wide spread blackout: (1) precise location of a fault so that only the circuit breakers necessary to isolate the fault are tripped, and (2) avoidance of unnecessary trips, due to hidden failure or overloading, by blocking the trip signals of conventional backup protection relays. The limitations of conventional backup protection are examined and methods of improvement are presented