The aim of this study was to analyze the influence of variations in the size of regions of interest (ROIs) on values of caudate glucose consumption [regional cerebral metabolic rate of glucose (rCMRglc)] assessed by PET. In addition, we tried to establish the influence of ROI size on levels of significance assessing differences in mean caudate glucose consumption between two groups of subjects. For this purpose, rCMRglc was measured using [18F]fluorodeoxyglucose and the PC-4096 PET camera with an in-plane resolution of 7.1 mm in 12 normal subjects and 12 subjects with early Huntington disease. Caudate rCMRglc was histographically determined using 10 different ROI widths ranging from 2 mm, corresponding to the peak value of caudate rCM-Rglc, to 20 mm. The increase in ROI width from 2 to 20 mm led to a significant decrease of caudate rCMRglc by approximately 66% in the normal subjects and in the patients. The Student t value assessing the differences in mean caudate rCMRglc between the two groups decreased gradually from 5.61 for an ROI width of 2 mm to 3.78 for an ROI width of 20 mm. This corresponds to a worsening of the level of significance from 10(-5) to 10(-3), i.e., by a factor of 100. These data show that (given the resolution of presently used PET cameras) the selection of peak values of caudate rCMRglc is the best way to discriminate between groups of subjects supposed to differ with respect to caudate rCMRglc.

Adult↗

PubMedDate not supplied

Multiorgan dysfunction syndrome: how water might contribute to its progression.

Multiorgan dysfunction syndrome (MODS) is one of the most frequent conditions encountered in intensive-care medicine. MODS is defined as total or partial loss of two or more organs with vital functions. The development of acute renal failure (ARF) in MODS leads to an additional aggravation with considerably higher hospital mortality than in other ICU patients with MODS. Whereas dissolved substances involved in the regulation of regional blood flow, endothelial cell injury, microvascular permeability, oxygenation, and nutrition of cells are at the focus of interest in MODS, hardly any scientific attention is paid to their main solvent water. An impaired renal water excretion and an increased metabolic water volume requiring excretion interfere with diffusive and convective oxygen transport through the different fluid compartments. It will be shown first that the ratio of U(osm)/ P(osm) appears to be a reliable tool to assess overhydration in ARF. Secondly, the limits of urinary output in response to water intake will be considered. Furthermore, the metabolic water formation by an enhanced degradation of endogenous protein and fat will be discussed. Finally, the daily caloric intake is questioned with respect to energy expenditure and metabolic water formation.

Aged↗

PubMedDate not supplied

Carbon arc plasma as a source of nanotubes: emission spectroscopy and formation mechanism.

Diagnostics of carbon arc plasma by optical emission spectroscopy during the synthesis of carbon nanotubes is reviewed. Spatial distributions of temperature and C2 radicals in different plasmas are presented. The influence of gas pressure, anode composition, and reaction environment is discussed. Mechanisms of carbon nanotube formation are reviewed, with an emphasis on surface diffusion processes and catalytic effects.

Carbon↗

PubMedDate not supplied

[Effect of N-methyl-N-beta-chloroethyl-hydrazine-HCl on the growth and multiplication of yeast cells (Saccharomyces cerevisiae) (author's transl)].

N-Methyl-N-beta-chloroethyl-hydrazine-HCl and its benzaldehydhydrazone inhibit growth and multiplication of yeast cells. The DNA-synthesis is partially blocked. After removal of the substances the rate of this synthesis is much more increased than that of RNA and protein. The both substances we tested are more effective than simple alkylhydrazines.

DNA↗