Koichiro Sera

Chemical characterization of particles in winter-night smog in Tokyo

Abstract Continuous measurement of PM 10 , PM 2.5 and carbon (organic, elemental composition) concentrations, and samples of PM 10 and PM 2.5 collected on a polycarbonate membrane filter (Nuclepore ® , pore size: 0.8xa0μm), were carried out during a period from December 1998 to January 1999 at Shinjuku in Tokyo in order to investigate the chemical characterization of particles in winter-night smog within a large area of the Japan Kanto Plain including the Tokyo Metropolitan area. These were measured using an ambient particulate monitor (tapered element oscillating microbalance—TEOM) and a carbon particulate monitor. Elemental compositions in the filter samples of PM 10 and PM 2.5 were determined by means of particle-induced X-ray emission (PIXE) analysis. Ionic species (anion: F − , Cl − , NO 3 − , SO 4 2− and C 2 O 4 2− ; cation: Na + , NH 4 + , K + , Ca 2+ and Mg 2+ ) in the filter samples were analyzed by ion chromatography. The temporal variation patterns of PM 2.5 were similar to those of PM 10 and carbon. PM 2.5 made up 90% of the PM 10 at a high concentration, and 70% at a low concentration. Concentrations of 22 elements in both the PM 10 and PM 2.5 samples were consistently determined by PIXE, and Na, Mg, Al, Si, S, Cl, K, Ca, Fe, Zn and Pb were found to be the major components. Among these S and Cl were the most dominant elements of the PM 2.5 and PM 10 at high concentrations. Ionic species were mainly composed of Cl − , NO 3 − , SO 4 2− and NH 4 + . The component proportion of carbon, the other elements (total amount of measured elements other than S and Cl) and secondary-formed particles of PM 2.5 was similar to that of PM 10 . The major component was carbon particles at a low concentration and secondary-formed particles at a high concentration. The proportion of NH 4 NO 3 and NH 4 Cl plus HCl in secondary-formed particles at a high concentration, in particular, was as high as 90%.

Trace elements in renal disease and hemodialysis

Abstract A number of considerations suggest that trace element disturbances might occur in patients with renal disease and in hemodialysis (HD) patients. Using particle induced X-ray emission, we demonstrated the relations between serum concentration, urinary excretion of the trace elements and creatinine clearance (Ccr) in randomized 50 patients. To estimate the effects of HD, we also observed the changes of these elements in serum and dialysis fluids during HD. Urinary silicon excretion decreased, and serum silicon concentration increased as Ccr decreased, with significant correlation ( r =0.702, p r =0.676, p r =0.452, p

Twenty-eight element concentrations in mane hair samples of adult riding horses determined by particle-induced X-ray emission

The concentrations of 28 elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Sr, Ti, V, Y, and Zn) were measured in mane hair by the particle-induced X-ray emission method. Except for Br, Cl, K, S, and P, the trace element concentrations in mane hair of horses are similar to literature values for human hair. The values obtained are not dependent on the horses age, breed, and sex and could be used as reference values in the assessment of diseases and nutritional status in equines.

TARGETED DELIVERY OF CHEMOTHERAPEUTIC AGENTS USING IMPROVED RADIOSENSITIVE LIQUID CORE MICROCAPSULES AND ASSESSMENT OF THEIR ANTITUMOR EFFECT

PURPOSEnRadiation-sensitive microcapsules composed of alginate and hyaluronic acid are being developed. We report the development of improved microcapsules that were prepared using calcium- and yttrium-induced polymerization. We previously reported on the combined antitumor effect of carboplatin-containing microcapsules and radiotherapy.nnnMETHODS AND MATERIALSnWe mixed a 0.1% (wt/vol) solution of hyaluronic acid with a 0.2% alginate solution. Carboplatin (l mg) and indocyanine green (12.5 microg) were added to this mixture, and the resultant material was used for capsule preparation. The capsules were prepared by spraying the material into a mixture containing a 4.34% CaCl(2) solution supplemented with 0-0.01% yttrium. These capsules were irradiated with single doses of 0.5, 1.0, 1.5, or 2 Gy (60)Co gamma-rays. Immediately after irradiation, the frequency of microcapsule decomposition was determined using a microparticle-induced X-ray emission camera. The amount of core content released was estimated by particle-induced X-ray emission and colorimetric analysis with 0.25% indocyanine green. The antitumor effect of the combined therapy was determined by monitoring its effects on the diameter of an inoculated Meth A fibrosarcoma.nnnRESULTSnMicrocapsules that had been polymerized using a 4.34% CaCl(2) solution supplemented with 5.0 x 10(-3)% (10(-3)% meant or 10%(-3)) yttrium exhibited the maximal decomposition, and the optimal release of core content occurred after 2-Gy irradiation. The microcapsules exhibited a synergistic antitumor effect combined with 2-Gy irradiation and were associated with reduced adverse effects.nnnCONCLUSIONnThe results of our study have shown that our liquid core microcapsules can be used in radiotherapy for targeted delivery of chemotherapeutic agents.

Standardized uptake value in high uptake area on positron emission tomography with 18F-FRP170 as a hypoxic cell tracer correlates with intratumoral oxygen pressure in glioblastoma.

PurposeThe aim of this study was to clarify the reliability of positron emission tomography (PET) using a new hypoxic cell tracer, 1-(2-[18F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (18F-FRP170).ProceduresTwelve patients with glioblastoma underwent 18F-FRP170 PET before tumor resection. Mean standardized uptake value (SUV) and normalized SUV were calculated at regions within a tumor showing high (high-uptake area) and relatively low (low-uptake area) accumulations of 18F-FRP170. In these areas, intratumoral oxygen pressure (tpO2) was measured using microelectrodes during tumor resection.ResultsMean tpO2 was significantly lower in the high-uptake area than in the low-uptake area. A significant negative correlation was evident between normalized SUV and tpO2 in the high-uptake area.ConclusionThe present findings suggest that high accumulation on 18F-FRP170 PET represents viable hypoxic tissues in glioblastoma.

Selective alterations of brain dopamine D2 receptor binding in cirrhotic patients: results of a 11C-N-methylspiperone PET study

Alterations of the brain dopamine system have been implicated in the neurological complications of chronic liver failure. The present study was aimed at the measurement of dopamine D2 binding sites in cirrhotic patients by positron emission tomography (PET) using 11C-N-methylspiperone as ligand. The regions of interest (ROI) were designated on a three-dimensional stereotaxic ROI template (3DSRT). The pixel values of twelve ROIs corrected by the pixel value of the cerebellum after 80xa0min static scanning were used to quantitate changes in binding. D2 binding sites were significantly decreased in the hippocampus and thalamus of cirrhotic patients and were positively correlated with serum bilirubin levels and Child–Pugh scores and were negatively correlated with prothrombin times (thalamus). Loss of D2 sites was greater in thalamus and hippocampus of alcoholic cirrhotics compared to non-alcoholics. Statistically significant correlations were also observed between D2 binding sites in hippocampus, thalamus and lenticular nuclei and history of overt encephalopathy. These findings suggest that D2 receptor binding in some regions of brain in cirrhotic patients is influenced by factors such as the severity of liver damage and history of alcohol dependency or overt encephalopathy. Alterations of D2 receptor sites indicative of dopaminergic synaptic dysfunction could play an important role in the pathogenesis of the cognitive and motor disturbances associated with chronic liver failure.

Influence of the Coat Color on the Trace Elemental Status Measured by Particle-Induced X-ray Emission in Horse Hair

The influence of hair color on the trace elemental status in horses hair has been studied. A current analytical technique such as particle-induced X-ray emission (PIXE) used in this study has provided reliable, rapid, easy, and relatively inexpensive diagnostic methods. Twenty-eight elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Ga, Hg, K, Mg, Mn, Mo, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Sr, Ti, V, Y, and Zn) in mane hair were detected by the PIXE method. The gray hair contains significantly greter amounts of Cu, Ti, and Zn, and lower amounts of Br, Ca, Se, and Sr than those in other colored horse hairs (p<0.05). Those results measured in the horses hair were similar to those found in human and dog hair. When interpreting a result, it should be kept in mind that hair color, especially gray hair, influences the concentrations of some elements in horse hair.

Correlation between 25 element contents in mane hair in riding horses and atrioventricular block

The influence of atrioventricular block (AV-block) on the trace elemental status in a horse hair was studied. The particle-induced X-ray emission (PIXE) method has provided a reliable, rapid, easy, and relatively inexpensive diagnostic method. Twenty-five elements (Al, Br, Ca, Cl, Co, Cu, Cr, Fe, Hg, K, Mg, Mn, Na, Nb, Ni, P, Pb, Rb, S, Se, Si, Ti, Y, and Zn) in mane hair and serum were measured by the PIXE method. A horse hair with first- and second-degree AV-block contained significantly greater amounts of Br, Ca, Sr, and Zn than those of horses without electrocardiographic abnormalities, whereas there was no significant differences in the elemental contents of the serum of the both groups. Those results in contents of a horse hair suggest that the evaluation of the degree of ionic imbalance by this method might be used to predict the susceptibility of a horse to heart disease much before symptoms appear.

SIMULTANEOUS MEASUREMENT OF TWO DIFFERENT TARGETS BY MEANS OF VACUUM AND IN-AIR PIXE

A simultaneous measuring system of two different targets by in-vacuum and in-air PIXE has been developed in order to improve efficiency of analyses in the limited machine time. The proton beam passes through a thin target in vacuum and it allows us to perform in-vacuum PIXE, and the beam is further transported to the in-air PIXE system for analyzing another target. The beam intensity for in-air PIXE while performing in-vacuum PIXE is 1.5 nA, which is almost sufficient. The effect of slight changes in the beam transport parameters on the background X-rays for both in-vacuum and in-air PIXE has been found to be negligible. As a result, it is confirmed that accuracy and sensitivity of analysis for many kinds of sample, such as various samples in earth, environmental sciences and in bio-medicine, are almost unchanged for the both systems, and a four-detector-simultaneous measuring system has been completed. It is expected that the system will work miracle for solving the problem of deficient machine time in our laboratory.

PHYSICAL QUANTITATIVE ANALYSIS IN IN-AIR PIXE

A physical method of quantitative analysis for in-air PIXE has been established. Among the three parameters required for performing physical analysis, X-ray production cross sections were recalculated by using the effective energy of the proton beam after losing its energy through a Kapton foil and in air. Detection efficiencies of the Si(Li) detector have been determined according to our method established for in vacuum system, where effects of absorption of X-rays in air are incorporated into the detection efficiencies. As a result, it is confirmed that the present method gives us accurate results in the analyses of standard samples as well as actual samples such as soil and ash. It becomes possible to perform quantitative analysis of various samples by optimizing the measuring conditions depending on the samples.