Development of a simple method to evaluate medical staff radiation dose and its application to a software system supporting PET facility operation

In recent years, positron-emitting labelled radiopharmaceuticals have come to be used in conjunction with positron emission tomography (PET) in various clinical diagnoses. Radiation exposure of the medical staff is a key issue in the design of PET facilities intended to handle large numbers of persons for PET diagnosis. As a first step, the radiation dose to individuals who received radiopharmaceuticals was calculated using a mathematical phantom model and the EGS4 electromagnetic cascade Monte Carlo code and MCNP Monte Carlo code. Dose rate behind a lead shield was also calculated for various lead thicknesses. The radiation dose distribution around a syringe containing a positron emitter was calculated. The calculated dose distributions were fitted to polynomial equations. These calculations were evaluated against measurements. The second step was to evaluate medical staff dose at a specified time by superimposing dose distribution from each person who received radioisotopes taking into account radioactive decay. In this way, we developed software to support PET facility operation, namely, planning, prediction, control of medical staff dose and facility operation. This system was also designed to schedule daily radiopharmaceuticals production and to manage radioactive wastes by taking decay time into account.     

Phenotypic alterations of neuropeptide Y, vasoactive intestinal peptide and choline acetyltransferase in rat cultured chromaffin cells as effected by nerve growth factor and glucocorticoid

We assessed changes in neuropeptide Y (NPY), vasoactive intestinal peptide (VIP) and choline acetyltransferase (ChAT) immunoreactivities when neonatal rat chromaffin cells were cultured in a medium containing nerve growth factor (NGF), or the synthetic glucocorticoid dexamethasone (DEX), examining whether their expression was correlated with the morphological changes induced by NGF and DEX. All of the chromaffin cells in culture were tyrosine hydroxylase (TH)-immunopositive regardless of whether they extended processes. TH-immunoreactive materials of NGF-treated chromaffin cells were distributed in all the cytoplasmic processes, even at the tips of growth cones. The percentage of NPY-positive chromaffin cells did not change markedly when treated with NGF or DEX throughout the 14 days in culture. The proportion of VIP-positive chromaffin cells increased gradually in the NGF-treated group and that of ChAT-positive cells in the group was similar to VIP. The morphological alterations induced by NGF were not correlated with the changes in proportions of NPY-, VIP- or ChAT-positive chromaffin cells. The percentages of VIP- or ChAT-immunopositive chromaffin cells in the NGF-treated group showed much greater increases than those in the DEX-treated group. These findings suggest that NGF might modulate the phenotypic changes of neuropeptides and amines in rat chromaffin cells.     

Predictive factors for in-hospital mortality and delayed mortality following aneurysmal subarachnoid hemorrhage

It is important to detect predictive factors for in-hospital and delayed mortality of patients with subarachnoid hemorrhage (SAH) due to ruptured aneurysm. Forty-eight patients with initial bleeding of aneurysmal SAH were referred to our hospital from January 1982 to December 1985. In-hospital mortality was 16.7% (8 to 48), and 15% (6) of forty patients died later during the follow-up period. Using the Kaplan-Meier method we were able to conclude that, cumulatively, there was 70.8% probability that much patients would survive for 10 years. We analysed predictive factors of in-hospital and delayed mortality retrospectively. The most significant predictive factor for in-hospital mortality was SAH grading on admission, and for delayed mortality (29.2%) age on admission was the best predictive factor. In fact, two patients died with cardiac event during the follow-up period. This result suggests that, although the SAH grading on admission was the second most significant factor for delayed mortality, patients who survived in the acute phase had a survival probability similar to those in a normal control group.     

Neoadjuvant intraarterial chemotherapy for ten cases of inflammatory breast cancer by Seldinger's methods

The conventional methods (CM) of intraarterial (IA) chemotherapy for inflammatory breast cancer were catheterizations from superior epigastric and brachial artery under general anesthesia. Since 1997, we selected the Seldinger's methods (SM) for ten cases of the disease to control local effects and simplify the technique. Complications of the SM were slight, and side effects were equal to those with CM. The postoperative pathological findings of the SM showed the direct effects of chemotherapy to tumor cells (degenerative and necrotic changes) as compared with the embolism-like effects of CM. But the overall histological effects of chemotherapy by SM were almost equal to those for CM. The strong points of the SM were as follows: 1) More selective IA chemotherapy is available, 2) one can find the passage of the aim vessels and no trouble related to catheter, 3) general anesthesia is not necessary, and the techniques are simple, 4) the wounds are not remarkable. The disadvantages are as follows: 1) Patients must rest the day of IA chemotherapy, 2) in 20% of the procedures, one can not search the vessels, and 3) in 4 cases complications of stiffness of Mj or Mn pectral muscles were found. In future, we expect more effective results by dose escalation or combination chemotherapy.     

One‐Pot/Four‐Step/Palladium‐Catalyzed Synthesis of Indole Derivatives: The Combination of Heterogeneous and Homogeneous Systems

One‐pot, four‐step syntheses of indoles using both solid‐supported heterogeneous and homogeneous palladium catalysts and reagents were carried out. Such a combination of these two‐phase catalysts and reagents causes a dramatic increase in yield, and it is a simple process. The presented methodology is effective for four‐step reactions to provide various functionalized indoles.     

Structure-Based Design,Synthesis, and Biological Evaluation of Imidazo[4,5-b]Pyridin-2-one-Based p38 MAP Kinase Inhibitors: Part 2

We identified novel potent inhibitors of p38 mitogen-activated protein (MAP) kinase using a structure-based design strategy, beginning with lead compound, 3-(butan-2-yl)-6-(2,4-difluoroanilino)-1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-one ( 1 ). To enhance the inhibitory activity of 1 against production of tumor necrosis factor-α (TNF-α) in human whole blood (hWB) cell assays, we designed and synthesized hybrid compounds in which the imidazo[4,5-b]pyridin-2-one core was successfully linked with the p-methylbenzamide fragment. Among the compounds evaluated, 3-(3-tert-butyl-2-oxo-2,3-dihydro-1H-imidazo[4,5-b]pyridin-6-yl)-4-methyl-N-(1-methyl-1H-pyrazol-3-yl)benzamide ( 25 ) exhibited potent p38 inhibition, superior suppression of TNF-α production in hWB cells, and also significant in vivo efficacy in a rat model of collagen-induced arthritis (CIA). In this paper, we report the discovery of potent, selective, and orally bioavailable imidazo[4,5-b]pyridin-2-one-based p38 MAP kinase inhibitors.     

Adaptation to climate change and conservation of biodiversity using green infrastructure

In recent years, we have experienced mega‐flood disasters in Japan due to climate change. In the last century, we have been building disaster prevention infrastructure (artificial levees and dams, referred to as “grey infrastructure”) to protect human lives and assets from floods, but these hard protective measures will not function against mega‐floods. Moreover, in a drastically depopulating society such as that in Japan, farmland abandonment prevails, and it will be more difficult to maintain grey infrastructure with a limited tax income. In this study, we propose the introduction of green infrastructure (GI) as an adaptation strategy for climate change. If we can use abandoned farmlands as GI, they may function to reduce disaster risks and provide habitats for various organisms that are adapted to wetland environments. First, we present a conceptual framework for disaster prevention using a hybrid of GI and conventional grey infrastructure. In this combination, the fundamental GI, composed of forests and wetlands in the catchment (GI‐1) and additional multilevel GIs such as flood control basins that function when floodwater exceeds the planning level (GI‐2) are introduced. We evaluated the flood attenuation function (GI‐1) of the Kushiro Wetland using a hydrological model and developed a methodology for selecting suitable locations of GI‐2, considering flood risk, biodiversity and the distribution of abandoned farmlands, which represent social and economic costs. The results indicated that the Kushiro Wetland acts as a large natural reservoir that attenuates the hydrological peak discharge during floods and suitable locations for introducing GI‐2 are concentrated in floodplain areas developing in the downstream reaches of large rivers. Finally, we discussed the network structure of GI‐1 as a hub and GI‐2 as a dispersal site for conservation of the Red‐crowned Crane, one of the symbolic species of Japan.     

Effect of lubricant fluid on plastic metal flow in sliding contact

Plastic metal flow in surface layers, especially “abnormal metal flow”, in which the direction of metal flow in the inner surface layer is different from that in the layer nearer the surface, in sliding contacts between a pin of cemented carbide and a ring of steel under lubrication is discussed in this paper. Low viscosity mineral oil is used as a base oil. Sulphide and chloride extreme pressure additives are also mixed with the base oil. Such a lubricant has a great influence on the plastic metal flow of a ring.While base oil produces severe plastic metal flow, the sulphide additive causes the plastic metal flow to be very mild. In contrast, a lubricant containing a chloride additive causes abnormal metal flow, where cracks can be seen. Conditions for and causes of abnormal metal flow are investigated.     

Biohybrid device with antagonistic skeletal muscle tissue for measurement of contractile force

ABSTRACT

This paper describes a fabrication method and driving property of a biohybrid device with an antagonistic pair of skeletal muscle tissues and a flexible substrate. Since two skeletal muscle tissues are symmetrically arranged with the flexible substrate as the central axis, the flexible substrate deforms according to differences in their tension. In the formation of the antagonistic pair of skeletal muscle tissues, we assembled myoblast-laden hydrogel sheets and cultured them to construct a single skeletal muscle tissue on each side of the flexible substrate. We confirmed that the skeletal muscle tissue on the flexible substrate had the fundamental morphology and function of skeletal muscle. Furthermore, we made the biohybrid device actuate with deformation of the flexible substrate by selective contractions of the skeletal muscle tissues. From the deformation of the flexible substrate, we estimated the contractile force of each skeletal muscle tissue in the biohybrid device using finite element analysis. This biohybrid device, composed of an antagonistic pair of skeletal muscle tissues and a flexible substrate, can potentially be used in biological studies and pharmacokinetic assays involving the antagonistic pair of skeletal muscles.