Accurate dose assessment system for an exposed person utilising radiation transport calculation codes in emergency response to a radiological accident.

A system has been developed to assess radiation dose distribution inside the body of exposed persons in a radiological accident by utilising radiation transport calculation codes-MCNP and MCNPX. The system consists mainly of two parts, pre-processor and post-processor of the radiation transport calculation. Programs for the pre-processor are used to set up a 'problem-dependent' input file, which defines the accident condition and dosimetric quantities to be estimated. The program developed for the post-processor part can effectively indicate dose information based upon the output file of the code. All of the programs in the dosimetry system can be executed with a generally used personal computer and accurately give the dose profile to an exposed person in a radiological accident without complicated procedures. An experiment using a physical phantom was carried out to verify the availability of the dosimetry system with the developed programs in a gamma ray irradiation field.

Effect of dried bonito (katsuobushi) and some of its components on GABAA receptors.

Katsuobushi, a popular Japanese food additive and traditional flavour enhancer, is produced from a fish, bonito, by a variety of processes, including boiling, sun drying, smoking and mould culturing. Aqueous katsuobushi (AK), which is produced from katsuobushi powder by extraction with water, and some of its aroma components, such as 2-ethyl-3-methylpyrazine and phenol derivatives, potentiated dose-dependently the response of the GABAA receptors expressed in Xenopus oocytes. When AK, 2-ethyl-3-methylpyrazine or 3-methoxyphenol were injected into mice prior to an intraperitoneal administration of pentobarbital, the pentobarbital-induced sleeping time increased. In an elevated plus maze test, intraperitoneal administration of 2-ethyl-3-methylpyrazine to mice increased significantly both the number of entries into the open arms and the duration of stay in the open arms, indicating anti-anxiety activity. Katsuobushi and its aroma components may modulate human mood or consciousness through acting on GABAA receptors in the brain.

Matrix metalloproteinase-9 is associated with blood-brain barrier opening and brain edema formation after cortical contusion in rats.

Matrix metalloproteinases (MMPs) are associated with blood-brain opening and may be involved in the pathophysiology of acute brain injury. Previous research demonstrated that knockout mice deficient in MMP-9 subjected to transient focal cerebral ischemia had reduced blood-brain barrier (BBB) disruption and attenuated cerebral infarction. In this study, we examined MMP-9 up-regulation, BBB disruption, and brain edema formation after cortical impact injury in rats. Cortical contusion was induced by controlled cortical impact. Animals were sacrificed at intervals after injury. MMP up-regulation was assessed by gelatin zymography, and BBB integrity was evaluated using Evans blue dye with a spectrophotometric assay. Brain water content was measured by comparing wet and dry weights of each hemisphere as an indicator of brain edema. Zymograms showed elevated MMP-9 as early as at 3 hours after injury, reaching a maximum at 18 hours. Peak levels of BBB disruption occurred 6 hours after injury. Brain edema became progressively more severe, peaking 24 hours after injury. Compared to control group, treatment with MMP-inhibitor GM6001 significantly reduced BBB disruption 6 hours and brain water content (85.9 +/- 0.5% vs. 82.6 +/- 0.3%; p < 0.05) 24 hours after injury. These findings suggest that MMP-9 may contribute to BBB disturbance and subsequent brain edema after traumatic brain injury.

The presequence of the precursor to the nucleus-encoded 30 kDa protein of photosystem II in Euglena gracilis Z includes two hydrophobic domains.

A cDNA clone for the extrinsic 30 kDa protein (OEC30) of photosystem II in Euglena gracilis Z was isolated and characterized. The open reading frame of the cDNA encoded a polypeptide of 338 amino acids, which consisted of a long presequence of 93 amino acids and a mature polypeptide of 245 amino acids. Two hydrophobic domains were identified in the presequence, in contrast to the presence of a single hydrophobic domain in the presequence of the corresponding proteins from higher plants. At the N- and C-terminal regions, respectively, of the presequence, a signal-peptide-like sequence and a thylakoid-transfer domain were identified. The presence of a long and unique presequence in the precursor to OEC30 is probably related to the complexity of the intracellular processes required for the synthesis and/or transport of the protein in Euglena.