Phosphate Energy Metabolism During Domoic Acid-Induced Seizures

The effect of domoic acid-induced seizure activity on energy metabolism and on brain pH in mice was studied by continuous EEC recording and in vivo 31 P nuclear magnetic resonance (NMR) spectroscopy. Mice were divided into ventilated (n = 6) and nonventilated (n = 7) groups. Baseline EEG was 0.1-mV amplitude with frequence of >30-Hz and of 4–5 Hz. After intraperitoneal (i.p.) administration of domoic acid (6 mg/kg), electro graphic spikes appeared at increasing frequency, pro gressing to high-amplitude (0.1-0.8 mV) continuous sei zure activity (status epilepticus). In ventilated mice, the [ 31 P]NMR spectra showed that high-energy phosphate levels and tissue pH did not change after domoic acid administration or during the intervals of spiking or status epilepticus. Nonventilated mice showed periods of EEG suppression accompanied by decreases in the levels of high-energy phosphate metabolites and in pH, corresponding to episodic respiratory suppression during the spiking interval. In all animals, status epilepticus was fol lowed by a marked decrease in EEG amplitude that pro gressed rapidly to isoelectric silence. [ 31 P]NMR spectra obtained after this were indicative of total energy failure and tissue acidosis. In a separate group of ventilated mice (n = 4), domoic acid-induced status epilepticus was ac companied initially by an increase in mean arterial blood pressure (MAP) that slowly returned to baseline level. Isoelectric silence was accompanied by a decrease in MAP to 75 ± 8 mm Hg. These experiments suggest that domoic acid-induced seizures are not accompanied by an increase in substrate demand that exceeds supply.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65953/1/j.1528-1157.1993.tb02124.x.pd

The Effect of Fluorine Doping on the Characteristic Behaviour of CdTe

Fluorine which is an n-type dopant of cadmium telluride thin films was included during growth from a cadmium nitrate [Cd(NO3)2Æ4H2O] bath using an electrodeposition technique. The fluorine concentration in the Cd(NO3)2Æ4H2O baths were varied between 0.5 ppm and 50 ppm in order to determine its effect on the optical, structural, morphological and electrical properties of the as-deposited and the post-growth-treated layers. These characterisations were carried out using x-ray diffraction, ultraviolet–visible spectrophotometry, scanning electron microscopy, energy dispersive x-rays spectroscopy, photoelectrochemical cell measurement, direct current conductivity measurement and fully fabricated device characterisation. The results are systematically reported in this paper

Is the maturity of hospitals' quality improvement systems associated with measures of quality and patient safety?

UNLABELLED: ABSTRACT: BACKGROUND: Previous research addressed the development of a classification scheme for quality improvement systems in European hospitals. In this study we explore associations between the 'maturity' of the hospitals' quality improvement system and clinical outcomes. METHODS: The maturity classification scheme was developed based on survey results from 389 hospitals in eight European countries. We matched the hospitals from the Spanish sample (113 hospitals) with those hospitals participating in a nation-wide, voluntary hospital performance initiative. We then compared sample distributions and explored associations between the 'maturity' of the hospitals' quality improvement system and a range of composite outcomes measures, such as adjusted hospital-wide mortality, -readmission, -complication and -length of stay indices. Statistical analysis includes bivariate correlations for parametrically and non-parametrically distributed data, multiple robust regression models and bootstrapping techniques to obtain confidence-intervals for the correlation and regression estimates. RESULTS: Overall, 43 hospitals were included. Compared to the original sample of 113, this sample was characterized by a higher representation of university hospitals. Maturity of the quality improvement system was similar, although the matched sample showed less variability. Analysis of associations between the quality improvement system and hospital-wide outcomes suggests significant correlations for the indicator adjusted hospital complications, borderline significance for adjusted hospital readmissions and non-significance for the adjusted hospital mortality and length of stay indicators. These results are confirmed by the bootstrap estimates of the robust regression model after adjusting for hospital characteristics. CONCLUSIONS: We assessed associations between hospitals' quality improvement systems and clinical outcomes. From this data it seems that having a more developed quality improvement system is associated with lower rates of adjusted hospital complications. A number of methodological and logistic hurdles remain to link hospital quality improvement systems to outcomes. Further research should aim at identifying the latent dimensions of quality improvement systems that predict quality and safety outcomes. Such research would add pertinent knowledge regarding the implementation of organizational strategies related with quality of care outcomes

Technical and Comparative Aspects of Brain Glycogen Metabolism.

It has been known for over 50 years that brain has significant glycogen stores, but the physiological function of this energy reserve remains uncertain. This uncertainty stems in part from several technical challenges inherent in the study of brain glycogen metabolism, and may also stem from some conceptual limitations. Factors presenting technical challenges include low glycogen content in brain, non-homogenous labeling of glycogen by radiotracers, rapid glycogenolysis during postmortem tissue handling, and effects of the stress response on brain glycogen turnover. Here, we briefly review aspects of glycogen structure and metabolism that bear on these technical challenges, and discuss ways these can be overcome. We also highlight physiological aspects of glycogen metabolism that limit the conditions under which glycogen metabolism can be useful or advantageous over glucose metabolism. Comparisons with glycogen metabolism in skeletal muscle provide an additional perspective on potential functions of glycogen in brain