A H-1 MRS study of probable Alzheimer's disease and normal aging: Implications for longitudinal monitoring of dementia progression

In order to evaluate the capability of H-1 MRS to monitor longitudinal changes in subjects with probable Alzheimer's disease (AD), the temporal stability of the metabolite measures N-acetylaspartate and N-acetylas-partylglutamate (NA), total Creatine (Cr), myo-Inositol (mI), total Choline (Chol), NA/Cr, mI/Cr, Chol/Cr and NA/mI were investigated in a cohort of normal older adults. Only the metabolite measures NA, mi, Cr, NA/Cr, mI/Cr, and NA/mI were found to be stable after a mean interval of 260 days. Relative and absolute metabolite measures from a cohort of patients with probable AD were subsequently compared with data from a sample of normal older adult control subjects, and correlated with mental status and the degree of atrophy in the localized voxel. Concentrations of NA, NA/Cr, and NA/mI were significantly reduced in the AD group with concomitant significant increases in mi and mI/Cr. There were no differences between the two groups in measures of Cr, Chol, or Chol/Cr. Significant correlations between mental status as measured by the Mini-Mental State Examination and NA/mI, mI/Cr and NA were found. These metabolite measures were also significantly correlated with the extent of atrophy (as measured by CSF and GM composition) in the spectroscopy voxel. (C) 1999 Elsevier Science Inc.

An evaluation of the time dependence of the anisotropy of the water diffusion tensor in acute human ischemia

We have performed MRI examinations to determine the water diffusion tensor in the brain of six patients who were admitted to the hospital within 12 h after the onset of cerebral ischemic symptoms. The examinations have been carried out immediately after admission, and thereafter at varying intervals up to 90 days post admission. Maps of the trace of the diffusion tensor, the fractional anisotropy and the lattice index, as well as maps of cerebral blood perfusion parameters, were generated to quantitatively assess the character of the water diffusion tensor in the infarcted area. In patients with significant perfusion deficits and substantial lesion volume changes, four of six cases, our measurements show a monotonic and significant decrease in the diffusion anisotropy within the ischemic lesion as a function of time. We propose that retrospective analysis of this quantity, in combination with brain tissue segmentation and cerebral perfusion maps, may be used in future studies to assess the severity of the ischemic event. (C) 1999 Elsevier Science Inc.

The breeding-season diet of wedge-tailed eagles (Aquila audax) in western New South Wales and the influence of Rabbit Calicivirus Disease

A total of 2071 individual prey items were identified from 34 active and 55 inactive wedge-tailed eagle nests following the 1995, 1996 and 1997 breeding seasons. Overall, the eagle's diet was comparable to that reported in other studies within semi-arid regions, with rabbits, reptiles and macropods accounting for 47.8, 22.6 and 13.7% of prey items, respectively. In spring 1996 rabbit calicivirus moved into the study area, resulting in a 44-78% reduction in rabbit abundance (Sharp et al. 2001). An index was developed to enable the time since death for individual prey items to be approximated and a historical perspective of the eagle's diet to be constructed. Rabbits constituted 56-69% of dietary items collected during the pre-rabbit calicivirus disease (RCD) samples, but declined to 31% and 16% in the two post-RCD samples. A reciprocal trend was observed for the proportion of reptiles in the diet, which increased from 8-21% of pre-RCD dietary items to 49-54% after the advent of RCD. Similarly, the proportion of avian prey items was observed to increase in the post-RCD samples. These data suggested that prey switching may have occurred following the RCD epizootic. However, a lack of data on the relative abundances of reptiles and birds prevented an understanding of the eagle's functional responses to be developed and definitive conclusions to be drawn. Nevertheless, the eagles were observed to modify their diet to the change in rabbit densities by consuming larger quantities of native prey species.

Establishment and characterization of a new epithelial cell line, KC-1, from koala (Phascolarctos cinereus) conjunctiva

A novel, untransformed koala cell line (KC-1) was established by culturing koala conjunctival tissue in growth medium, which has permitted the study of the cell biology of this unique system. After the establishment of the KC-1 cell line, the cells were characterized by light microscopy, doubling time, and Western blot analysis. Light microscopy revealed that the cells have an epithelial morphology. Doubling times were significantly different (P < 0.015) depending on fetal calf serum (FCS) concentration (16.5 h in 10% FCS and 26.5 h in 2% FCS). Cells constricted while in suspension but were shown to attach to the coverslip (or flask) and flatten rapidly, less than 1 h after seeding. To confirm the epithelial nature of the cells, protein was extracted and Western blot analysis was performed. Subsequent probing with primary and secondary antibodies (monoclonal anticytokeratin clone C-11 IgG1 and anti-mouse IgG) revealed two bands at 45 and 52 kDa (compared against a protein molecular weight marker) that correspond to primary type I keratin and major type II keratin, respectively, expressed in simple epithelial cells. The koala cell line was adapted to grow continuously in Dulbecco modified Eagle medium containing 10% FCS for at least 30 passages. This unique cell line is an ideal toot for further investigation on koala cell biology and cytogenetics and for exploration of the pathophysiological mechanism of eye infections caused by different pathogens in koalas.

Risk of serious NSAID-related gastrointestinal events during long-term exposure: a systematic review

Objective: Exposure to non-steroidal anti-inflammatory drugs (NSAIDs) is associated wit increased risk of serious gastrointestinal (GI) events compared with non-exposure. We investigated whether that risk is sustained over time. Data sources: Cochrane Controlled Trials Register (to 2002); MEDLINE, EMBASE, Derwent Drug File and Current Contents (1999-2002); manual searching of reviews (1999-2002). Study selection: From 479 search results reviewed and 221 articles retrieved, seven studies of patients exposed to prescription non-selective NSAIDs for more than 6 months and reporting time-dependent serious GI event rates were selected for quantitative data synthesis. These were stratified into two groups by study design. Data extraction: Incidence of GI events and number of patients at specific time points were extracted. Data synthesis: Meta-regression analyses were performed. Change in risk was evaluated by testing whether the slope of the regression line declined over time. Four randomised controlled trials (RCTs) provided evaluable data from five NSAID arms (aspirin, naproxen, two ibuprofen arms, and diclofenac). When the RCT data were combined, a small significant decline in annualised risk was seen: -0.005% (95% Cl, -0.008% to -0.001%) per month. Sensitivity analyses were conducted because there was disparity within the RCT data. The pooled estimate from three cohort studies showed no significant decline in annualised risk over periods up to 2 years: -0.003% (95% Cl, -0.008% to 0.003%) per month. Conclusions: Small decreases in risk over time were observed; these were of negligible clinical importance. For patients who need long-term (> 6 months) treatment, precautionary measures should be considered to reduce the net probability of serious GI events over the anticipated treatment duration. The effect of intermittent versus regular daily therapy on long-term risk needs further investigation.

A late Pleistocene predator-accumulated avifauna from Kids Cave, West Coast, South Island, New Zealand

A fossil deposit excavated from the floor of Kids Cave, West Coast, South Island, New Zealand, is interpreted as having been primarily accumulated by New Zealand falcon Falco novaeseelandiae, with some contribution by Haast's eagle Harpagornis moorei. The fauna is rich: 3699 bones represented 41 bird species, two frog species, unspecified geckoes and skinks, and one bat species. Fossil deposition was mainly within the Last Glacial Maximum from about 22,000 cal yr bp to about 15,000 cal yr bp, with a marked change in sediment characteristics at the onset of the LGM's coldest period. Chronological control is given by three Uranium-series dates for a speleothem and radiocarbon AMS dating of four avian eggshell samples and one bone. The fauna is the first extensive predator accumulation of LGM age described from the West Coast of the South Island, and it indicates a palaeoenvironment of a mosaic of shrublands with forest patches. The onset of the coldest part of the LGM (Aurora 3 glacial advance, 19,500 - 19,000 cal yrs bp) saw marked climate cooling/drying affecting the site, but the avifauna indicates that although open-country taxa became more common in this period, some forest persisted nearby throughout the remainder of the LGM.

Hydrogen from coal: Production and utilisation technologies

Error condition detected Although coal may be viewed as a dirty fuel due to its high greenhouse emissions when combusted, a strong case can be made for coal to be a major world source of clean H-2 energy. Apart from the fact that resources of coal will outlast oil and natural gas by centuries, there is a shift towards developing environmentally benign coal technologies, which can lead to high energy conversion efficiencies and low air pollution emissions as compared to conventional coal fired power generation plant. There are currently several world research and industrial development projects in the areas of Integrated Gasification Combined Cycles (IGCC) and Integrated Gasification Fuel Cell (IGFC) systems. In such systems, there is a need to integrate complex unit operations including gasifiers, gas separation and cleaning units, water gas shift reactors, turbines, heat exchangers, steam generators and fuel cells. IGFC systems tested in the USA, Europe and Japan employing gasifiers (Texaco, Lurgi and Eagle) and fuel cells have resulted in energy conversions at efficiency of 47.5% (HHV) which is much higher than the 30-35% efficiency of conventional coal fired power generation. Solid oxide fuel cells (SOFC) and molten carbonate fuel cells (MCFC) are the front runners in energy production from coal gases. These fuel cells can operate at high temperatures and are robust to gas poisoning impurities. IGCC and IGFC technologies are expensive and currently economically uncompetitive as compared to established and mature power generation technology. However, further efficiency and technology improvements coupled with world pressures on limitation of greenhouse gases and other gaseous pollutants could make IGCC/IGFC technically and economically viable for hydrogen production and utilisation in clean and environmentally benign energy systems. (c) 2005 Elsevier B.V. All rights reserved.