Investigation of changes in the iodine concentrations of oceanic sediment and terrestrial soil samples after thermal drying

To certify the suitability of pretreatment by thermal drying to measure iodine concentrations of oceanic sediment and terrestrial soil samples, changes in iodine concentrations after drying (50, 80 or 85, and 110 °C for 48 h) were examined using the samples in addition to a terrestrial plant (pine needles), which was selected as an intact organic sample. The iodine concentrations per wet weight of the sediment and soil samples processed by thermal drying were comparable to those of the raw samples at all temperatures. However, the concentrations of the plant samples dried at 85 and 110 °C were lower than those of the raw samples. The lower concentrations of the plant samples at higher temperatures were considered to be derived from the volatilization of a part of the plant's organic matter. Finally, these results suggested that the iodine concentrations in oceanic sediment and terrestrial soil samples scarcely change after thermal drying at 110 °C, although the concentrations may decrease when these samples include high contributions of fresh organic matter.

DISTRIBUTION OF RADIOCESIUM IN BLACK PINE TREE FORESTS IN ROKKASHO, AOMORI, JAPAN

Since the Fukushima Dai-ichi Nuclear Power Plant (FDNNP) accident in 2011, 134Cs had been detected in atmospheric deposition samples collected in Rokkasho and Aomori in Japan, located ~400-km north of the FDNNP, during March 2011-May 2015. To study the distribution of radiocesium (134, 137Cs) in a Japanese black pine tree forest, we measured the activity concentration of 134, 137Cs in whole black pine trees, including roots collected during 2017-19 along with soil samples in 2015 and 2017-19. The results show that most of the deposited 134Cs was retained in the forest floor in 2015, with depth distribution different from that of the weapon testing fallout. Proportions of the weapon fallout 137Cs in trunks, branches, needles and roots were 44, 17, 13 and 26%, respectively, indicating that >50% of 137Cs in above-ground part existed in the trunks. The total inventories of 134Cs and 137Cs in the forest were estimated to be 8.9 and 2.5·103 Bq m-2, respectively, and ~4.8% of 137Cs inventory was originated from the accident. Inventory of 134Cs in the forest-including the black pine trees-was 1.6 times larger than cumulative deposition outside of the forest due to the canopy effect.

Ten-year radiocesium fluvial discharge patterns from watersheds contaminated by the Fukushima nuclear power plant accident

After the Fukushima Dai-ichi nuclear power plant accident in March 2011, the fluvial discharge of ¹³⁷Cs from watersheds to rivers was analyzed between 2011 and 2021. The concentrations of dissolved and particulate ¹³⁷Cs were measured in river water samples collected from two rivers (the Hiso and Wariki rivers, mainly draining farmlands and forests, respectively) draining approximately 4-7 km² watersheds in a montane area (the areal deposition of ^134+137Cs; 1-3 MBq·m^-2 in March 2011) of Iitate Village, Fukushima. Over the 10 yr analysis, the particulate ¹³⁷Cs concentrations in the Hiso and Wariki rivers decreased by 70 and 50 times, respectively, and that of the dissolved form decreased by 150 and 130 times, respectively. Moreover, the apparent K_d (distribution coefficient) of ¹³⁷Cs for water samples from both rivers have increased gradually over these periods. In 2011, the ¹³⁷Cs discharge rates through the Hiso and Wariki rivers were 0.63% and 0.46% per year of the total amount of ¹³⁷Cs deposited in their catchments, respectively; however, by 2021, these rates had decreased to 0.09% and 0.03% per year. The cumulative ¹³⁷Cs discharge rates over 10 yr in the farmland- and forest-dominated rivers were 1.95% and 1.33%, respectively. These rates of the farmland-dominated river were ∼1.4-fold greater than those of the forest-dominated river. Moreover, ∼90% of the of the discharge occurred in particulate form while the remaining ∼10% was in the dissolved form. Thus, ¹³⁷Cs deposited within these watersheds due to the accident was gradually discharged by the rivers over the 10-yr period; however, the majority remains stored in soils and litters etc. of the catchment area. These results indicate that ¹³⁷Cs outflow from land-to-ocean will be limited in the future, as the river export of ¹³⁷Cs is expected to continue decreasing.

Concentrations of iodine-129 in coastal surface sediments around spent nuclear fuel reprocessing plant at Rokkasho, Japan, during and after its test operation

Concentrations of 129I in coastal surface sediment samples from the east coast of Aomori, Japan, 2–65 km away from the wastewater outlet of the nuclear fuel reprocessing plant at Rokkasho, Japan, were measured from 2006 to 2010. No clear effect on 129I/127I atom ratios in marine sediments was observed, although 129I was discharged from the plant, during its test operation using actual spent fuel, mainly between 2006 and 2008. The ratio in sediments collected at a fishing port at the mouth of a brackish lake increased in 2007, showing that the 129I migrated from the lake to the port.

Regional and global contributions of anthropogenic iodine-129 in monthly deposition samples collected in North East Japan between 2006 and 2015

We measured the monthly atmospheric deposition flux of ¹²⁹I at Rokkasho, Aomori, Japan-the location of a commercial spent nuclear fuel reprocessing plant-from 2006 to 2015 to assess the impact of the plant on environmental ¹²⁹I levels. The plant is now under final safety assessment by a national authority after test operation using actual spent nuclear fuel. During cutting and chemical processing in test operations from April 2006 to October 2008, ¹²⁹I was discharged to the atmosphere and detected in our deposition samples. ¹²⁹I deposition fluxes largely followed the discharge pattern of ¹²⁹I from the plant to the atmosphere, and most of the deposited ¹²⁹I originated from the plant. In and after 2009, ¹²⁹I deposition fluxes decreased dramatically to reach the background level; the ¹²⁹I deposition fluxes at Rokkasho were almost the same as those at Hirosaki, where an additional sampling point was set up as a background site 85 km from the plant in 2011. The background ¹²⁹I deposition fluxes showed seasonal variation-high in winter and low in the other seasons-at both Rokkasho and Hirosaki. The results of a backward trajectory analysis of the air mass at Rokkasho suggested that reprocessing plants in Europe were the origins of the high ¹²⁹I flux in winter. The contribution of ¹²⁹I released from the Fukushima Dai-ichi Nuclear Power Plant accident to the ¹²⁹I deposition flux at Rokkasho in 2011 was small on the basis of the ¹²⁹I/¹³¹I activity ratio.

Vertical distribution of radiation dose rates in the water of a brackish lake in Aomori Prefecture, Japan

Seasonal radiation dose rates were measured with glass dosemeters housed in watertight cases at various depths in the water of Lake Obuchi, a brackish lake in Aomori Prefecture, Japan, during fiscal years 2011-2013 to assess the background external radiation dose to aquatic biota in the lake. The mean radiation dose in the surface water of the lake was found to be 27 nGy h(-1), which is almost the same as the absorption dose rate due to cosmic ray reported in the literature. Radiation dose rates decreased exponentially with water depth down to a depth of 1 m above the bottom sediment. In the water near the sediment, the dose rate increased with depth owing to the emission of γ-rays from natural radionuclides in the sediment.

Effects of radiocesium inventory on (137)Cs concentrations in river waters of Fukushima, Japan, under base-flow conditions

To investigate the behavior of nuclear accident-derived (137)Cs in river water under base-flow conditions, concentrations of dissolved and particulate (137)Cs were measured at 16 sampling points in seven rivers of Fukushima Prefecture, Japan, in 2012 and 2013. The concentration of dissolved (137)Cs was significantly correlated with the mean (137)Cs inventory in the catchment area above each sampling point in both sampling years. These results suggest that the concentration of dissolved (137)Cs under base-flow conditions is primarily determined by the (137)Cs inventory of the catchment area above the sampling point. However, the concentration of particulate (137)Cs did not show a clear relationship with either the mean (137)Cs inventory or the dissolved (137)Cs concentration, thus indicating that particulate and dissolved forms do not effectively interact in rivers. To evaluate the contribution of the (137)Cs inventory within catchment areas, we analyzed relations between the (137)Cs concentration and the mean (137)Cs inventory over the area within certain flow path lengths that were traced along the river and slope above the sampling point. Coefficients of determination for dissolved (137)Cs concentrations were highest for the longest flow path, i.e., the whole catchment area, and lower for shorter flow paths. Coefficients of determination for particulate (137)Cs concentrations were only moderately high for the shortest flow path in 2012, whereas the values were quite low for all flow paths in 2013. These results suggest that dissolved (137)Cs can originate from a larger area of the catchment even under base-flow conditions; however, particulate (137)Cs did not show such behavior. The results also show that under base-flow conditions, dissolved and particulate (137)Cs behave independently during their transport from river catchments to the ocean.

A high incidence of WT1 abnormality in bilateral Wilms tumours in Japan, and the penetrance rates in children with WT1 germline mutation

Background:

Bilateral Wilms tumours (BWTs) occur by germline mutation of various predisposing genes; one of which is WT1 whose abnormality was reported in 17–38% of BWTs in Caucasians, whereas no such studies have been conducted in East-Asians. Carriers with WT1 mutations are increasing because of improved survival.

Methods:

Statuses of WT1 and IGF2 were examined in 45 BWTs from 31 patients with WT1 sequencing and SNP array-based genomic analyses. The penetrance rates were estimated in WT1-mutant familial Wilms tumours collected from the present and previous studies.

Results:

We detected WT1 abnormalities in 25 (81%) of 31 patients and two families, which were included in the penetrance rate analysis of familial Wilms tumour. Of 35 BWTs from the 25 patients, 31 had small homozygous WT1 mutations and uniparental disomy of IGF2, while 4 had large 11p13 deletions with the retention of 11p heterozygosity. The penetrance rate was 100% if children inherited small WT1 mutations from their fathers, and 67% if inherited the mutations from their mothers, or inherited or had de novo 11p13 deletions irrespective of parental origin (P=0.057).

Conclusions:

The high incidence of WT1 abnormalities in Japanese BWTs sharply contrasts with the lower incidence in Caucasian counterparts, and the penetrance rates should be clarified for genetic counselling of survivors with WT1 mutations.

Autosomal recessive cystinuria caused by genome-wide paternal uniparental isodisomy in a patient with Beckwith-Wiedemann syndrome

Approximately 20% of Beckwith-Wiedemann syndrome (BWS) cases are caused by mosaic paternal uniparental disomy of chromosome 11 (pUPD11). Although pUPD11 is usually limited to the short arm of chromosome 11, a small minority of BWS cases show genome-wide mosaic pUPD (GWpUPD). These patients show variable clinical features depending on mosaic ratio, imprinting status of other chromosomes, and paternally inherited recessive mutations. To date, there have been no reports of a mosaic GWpUPD patient with an autosomal recessive disease caused by a paternally inherited recessive mutation. Here, we describe a patient concurrently showing the clinical features of BWS and autosomal recessive cystinuria. Genetic analyses revealed that the patient has mosaic GWpUPD and an inherited paternal homozygous mutation in SLC7A9. This is the first report indicating that a paternally inherited recessive mutation can cause an autosomal recessive disease in cases of GWpUPD mosaicism. Investigation into recessive mutations and the dysregulation of imprinting domains is critical in understanding precise clinical conditions of patients with mosaic GWpUPD.

Ultrafast time-resolved magneto-optical imaging of all-optical switching in GdFeCo with femtosecond time-resolution and a μm spatial-resolution

We developed an ultrafast time-resolved magneto-optical (MO) imaging system with several millidegree resolution of light polarization angle, 100 fs time-resolution, and a micrometer spatial resolution. A CCD camera with about 10(6) pixels is used for detection and MO images with an absolute angle of the light polarization are acquired by the rotating analyzer method. By optimizing the analysis procedure with a least square method and the help of graphical processor units, this novel system significantly improves the speed for MO imaging, allowing to obtain a MO map of a sample within 15 s. To demonstrate the strength of the technique, we applied the method in a pump-and-probe experiment of all-optical switching in a GdFeCo sample in which we were able to detect temporal evolution of the MO images with sub-picosecond resolution.

A novel de novo point mutation of the OCT-binding site in the IGF2/H19-imprinting control region in a Beckwith-Wiedemann syndrome patient

The IGF2/H19-imprinting control region (ICR1) functions as an insulator to methylation-sensitive binding of CTCF protein, and regulates imprinted expression of IGF2 and H19 in a parental origin-specific manner. ICR1 methylation defects cause abnormal expression of imprinted genes, leading to Beckwith-Wiedemann syndrome (BWS) or Silver-Russell syndrome (SRS). Not only ICR1 microdeletions involving the CTCF-binding site, but also point mutations and a small deletion of the OCT-binding site have been shown to trigger methylation defects in BWS. Here, mutational analysis of ICR1 in 11 BWS and 12 SRS patients with ICR1 methylation defects revealed a novel de novo point mutation of the OCT-binding site on the maternal allele in one BWS patient. In BWS, all reported mutations and the small deletion of the OCT-binding site, including our case, have occurred within repeat A2. These findings indicate that the OCT-binding site is important for maintaining an unmethylated status of maternal ICR1 in early embryogenesis.

Daily radionuclide ingestion and internal radiation doses in Aomori prefecture, Japan

To assess internal annual dose in the general public in Aomori Prefecture, Japan, 80 duplicate cooked diet samples, equivalent to the food consumed over a 400-d period by one person, were collected from 100 volunteers in Aomori City and the village of Rokkasho during 2006–2010 and were analyzed for 11 radionuclides. To obtain average rates of ingestion of radionuclides, the volunteers were selected from among office, fisheries, agricultural, and livestock farm workers. Committed effective doses from ingestion of the diet over a 1-y period were calculated from the analytical results and from International Commission on Radiological Protection dose coefficients; for 40K, an internal effective dose rate from the literature was used. Fisheries workers had significantly higher combined internal annual dose than the other workers, possibly because of high rates of ingestion of marine products known to have high 210Po concentrations. The average internal dose rate, weighted by the numbers of households in each worker group in Aomori Prefecture, was estimated at 0.47 mSv y-1. Polonium-210 contributed 49% of this value. The sum of committed effective dose rates for 210Po, 210Pb, 228Ra, and 14C and the effective dose rate of 40K accounted for approximately 99% of the average internal dose rate.

Fluvial discharges of radiocaesium from watersheds contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident, Japan

A large amount of radiocaesium, (134)Cs and (137)Cs, was released to the atmosphere and Pacific Ocean from the Tokyo Electric Power Company's Fukushima Dai-ichi Nuclear Power Plant (FDNPP) that was damaged by the tsunami caused by the Tohoku earthquake on 11 March 2011. Radiocaesium deposited on the ground is now the most important consideration in assessing the risk to people in the vicinity of the FDNPP and remediating the contaminated area. Transfer of radiocaesium from the ground through rivers is an important factor in the downstream contamination of irrigation waters, paddy fields, lakes, and the sea. We estimated the transport of radiocaesium through two small rivers, the Hiso River and Wariki River, that traverse mountainous areas in Fukushima Prefecture. Areal depositions of radiocaesium in their watersheds (catchments) were high (1-3 MBq m(-2)). Water samples were collected from the rivers twice during each of two baseflow and two flood stages in 2011 and analysed for radiocaesium in particulate and dissolved forms. The radiocaesium concentrations depended strongly on the rates of water discharge. Maximum activities of radiocaesium in the samples from the Hiso River and Wariki River when there was precipitation or flooding (July and September) were 25 ± 0.31 and 35 ± 0.25 Bq L(-1), respectively. Particulate radiocaesium during periods of flooding contributed over 90% of the total radiocaesium activity in the samples. The discharge of radiocaesium from the catchments during 2011 was estimated to be 0.5% and 0.3% of the total amount of radiocaesium deposited on the catchments of the Hiso River and Wariki River, respectively. It is considered that the most of the radiocaesium deposited in the catchment remains on the soil surface.

Abnormal fast activity before the onset of West syndrome

In our sequential EEG study performed on 68 infants with various pre- and perinatal brain insults, we found peculiar abnormal fast activity (AFAs) in 12 patients. 9 of the 12 patients with AFAs later developed West syndrome (WS) compared with only 3 of the 56 patients without AFAs (p<0.001, χ(2) test). We analyzed these AFAs using EEG topography, and compared them with ictal fast activity (IFA) corresponding to tonic spasms observed later in the same patients after they had developed WS. We also investigated the clinical and EEG features in these patients. AFAs were first observed commonly at 4-5 months of CA, before the onset of WS. AFA topographic maps revealed posterior predominance in 11 of the 12 patients; IFA maps also showed posterior predominance but were more widely distributed. We propose that, though AFAs and IFAs are different, they share certain aspects of their pathophysiology, and that the maturational process of the occipital cortex plays an important role in the shared aspects. Since AFAs are observed before the onset of WS, they can be considered a sign that WS is imminent.

Concentrations of 137Cs, 90Sr, 108m Ag, 239+240 Pu and atom ratio of 240Pu/239Pu in tanner crabs, Chionoecetes japonicus and Chionoecetes opilio collected around Japan

The anthropogenic radionuclides, (137)Cs, (90)Sr, (108m)Ag, (239+240)Pu, were measured in two Chionoecetes species, red queen crab (Chionoecetes japonicus) and snow crab (Chionoecetes opilio) collected around Japan during 1996-2007. There was no increase in the concentrations of these radionuclides and no large variation of the atom ratio of (240)Pu/(239)Pu during this research period. These results indicated that the source of the radionuclides was not the radioactive wastes dumped by the former USSR and Russia and originated from past nuclear weapon tests. The higher atom ratio in the crab species than that from global fallout would be contributed by the Pacific Proving Grounds close-in fallout. The variability of the concentration of radionuclides in the crab species would result from the variability of the composition and quantity in the diet. However, the decrease in the concentration of radionuclides with sampling depth would depend on the concentration in the seawater and diet.

Uranium isotopes in well water samples as drinking sources in some settlements around the Semipalatinsk Nuclear Test Site, Kazakhstan

Radiochemical results of U isotopes (234U, 235U and 238U) and their activity ratios are reported for well waters as local sources of drinking waters collected from the ten settlements around the Semipalatinsk Nuclear Test Site (SNTS), Kazakhstan. The results show that 238U varies widely from 3.6 to 356 mBq/L (0.3-28.7 μg/L), with a factor of about 100. The 238U concentrations in some water samples from Dolon, Tailan, Sarzhal and Karaul settlements are comparable to or higher than the World Health Organization's restrictive proposed guideline of 15 μg (U)/L. The 234U/238U activity ratios in the measured water samples are higher than 1, and vary between 1.1 and 7.9, being mostly from 1.5 to 3. The measured 235U/238U activity ratios are around 0.046, indicating that U in these well waters is of natural origin. It is probable that the elevated concentration of 238U found in some settlements around the SNTS is not due to the close-in fallout from nuclear explosions at the SNTS, but rather to the intensive weathering of rocks including U there. The calculated effective doses to adults resulting from consumption of the investigated waters are in the range 1.0-18.7 μSv/y. Those doses are lower than WHO and IAEA reference value (100 μSv/y) for drinking water.

Mycophenolate mofetil therapy for childhood-onset steroid dependent nephrotic syndrome after long-term cyclosporine: extended experience in a single center

BACKGROUND

Mycophenolate mofetil (MMF) is being used increasingly in children with steroid-dependent nephrotic syndrome (SDNS). However, there is limited information on the optimal therapeutic range for mycophenolic acid (MPA), the active metabolite of MMF, in these patients.

METHODS

26 patients with SDNS (mean age 13.1 years, 19 with minimal change disease and 7 with focal segmental glomerulosclerosis) who had received MMF for at least 6 months after longterm cyclosporine (CsA, mean 56 months) at Saitama Children's Medical Center between September 2002 and August 2008 were analyzed. MMF was introduced at an initial dose of 250 mg/12 h, adjusted to maintain target predose MPA at greater than 2 microg/ml (maximum 1 g twice daily) gradually over 4 weeks. After the introduction of MMF, the dosages of both CsA and prednisolone (PSL) were tapered off if possible.

RESULTS

The mean MMF dose required was 34 +/- 6 mg/kg, which maintained the mean predose MPA levels of 3.1 mg/ml. In 26 patients, treatment with MMF for a mean follow-up period of 19 months (range 7 - 42), resulted in a reduction of the mean PSL dose from 0.33 +/- 0.23 to 0.17 +/- 0.11 mg/kg per day (p < 0.01) and mean CsA dose from 3.2 +/- 1.7 to 1.3 +/- 1.8 mg/kg per day (p < 0.01). The mean 12-monthly relapse rates decreased from 2.5 +/- 1.4 to 0.8 +/- 1.2 episodes (p < 0.01). In 20 patients treated with MMF (77%), the dose of PSL and/or CsA was successfully tapered with a reduction in the relapse rates. In 6 patients, however, CsA therapy was reintroduced or its dose was increased because of treatment failure. The patients whose average predose MPA levels were less than 3 microg/ml were significantly likely to have treatment failure (p < 0.05). 2 patients reduced the MMF dosage because of anemia or herpes labialis. However, no severe gastrointestinal discomfort was seen in any patients. Despite long-term CsA therapy, marked tubulointerstitial fibrosis developed during MMF therapy in surveillance biopsies of only one of these five patients.

CONCLUSIONS

Therapy with MMF based on the predose MPA levels can be a less toxic alternative to CsA or in some cases a useful additional medication to allow for a reduction in the CsA and/or PSL dosage.

Inventories of 239+240Pu, 137Cs, and excess 210Pb in sediments from freshwater and brackish lakes in Rokkasho, Japan, adjacent to a spent nuclear fuel reprocessing plant

We investigated the vertical profiles of (239+240)Pu, (137)Cs, and excess (210)Pb ((210)Pb(ex)) in sediment core samples obtained from two freshwater lakes and two brackish lakes situated near the first commercial spent nuclear fuel reprocessing plant in Rokkasho, Japan, before the final test of the plant using actual spent nuclear fuel. The inventory of (239+240)Pu in those lakes was larger than that in soil in Rokkasho, which indicated the inflow of (239+240)Pu from the catchment area in addition to direct deposition on the lake surfaces. The (137)Cs inventory in sediments of the brackish lakes was lower than that in the soil, which showed that part of the (137)Cs was removed from the sediments by the brackish water or that it was not deposited into the sediments, because of the high solubility of Cs in brackish water. The (137)Cs inventory in sediments of the freshwater lakes was higher than that of the brackish lakes, and comparable with that in soil except for one core sample out of four. The (239+240)Pu/(137)Cs ratio in freshwater lake sediments was higher than that in soil, and that indicated that part of the (137)Cs was lost from the sediments. The low inventory of (137)Cs may be attributable to competition for absorption sites in sediments with ammonium ions formed in the reducing environment which occurs from summer to fall in the sediments. Those data will be used as background data on the artificial radionuclides in the lakes to assess the effect of released radionuclides on their concentrations.

Characterization of non-linear relationship between total and unbound serum concentrations of valproic acid in epileptic children

OBJECTIVE

To establish a regression equation to properly estimate the unbound serum concentration of valproic acid (VPA) from its total serum concentration; the relationship between total and unbound serum VPA concentrations was retrospectively characterized.

METHODS

Data were obtained from the clinical examination records that were routinely archived during therapeutic drug monitoring. The screening encompassed 342 records of 108 paediatric patients whose total and unbound VPA concentrations had been determined. The relationship between total and unbound VPA concentrations was characterized according to the Langmuir equation by taking account of inter-individual variability with the nonmem program.

RESULTS

The total VPA concentration (C(t)) in the screened patients ranged from 5.5 to 179.8 microg/mL, and the unbound VPA concentration (C(f)) increased in a non-linear manner as the total VPA concentration increased. Taking account of the effects of antiepileptics concurrently administered, the VPA dissociation constant (K(d)) and maximum binding site concentration (B(m)) were 7.8 +/- 0.7 and 130 +/- 4.5 microg/mL respectively, for the regression equation, C(t) = C(f) + B(m) x C(f)/(K(d) + C(f)). An alteration in the unbound concentration was seen in patients who were treated with the combination of VPA and ethosuximide and in those who received two additional antiepileptics.

CONCLUSIONS

A regression equation for estimation of the unbound VPA concentration, based on total VPA concentration collected during routine therapeutic drug monitoring was established. Use of two additional antiepileptics and ethosuximide treatment was considered as potential factors affecting unbound VPA concentration.

Relation of spasms and myoclonus to suppression-burst on EEG in epileptic encephalopathy in early infancy

PURPOSE

This study was intended to clarify the relation between spasms in series and a suppression-burst (SB) EEG pattern which have a common nature of repetitive bursting activity in epileptic encephalopathy in early infancy.

METHODS

The ictal EEG traces of spasms were temporally compressed and expanded to study the beginning and ending phases of series along with their spectral analysis in two patients with Ohtahara syndrome (OS) and one with early myoclonic encephalopathy (EME). The EEG bursts associated with myoclonus were also investigated.

RESULTS

A mutual transition was indicated between the ictal activity of spasms and the bursts in the peri-series SB on EEG. Gamma rhythm was detected in common in the ictal activity and the peri-series and interictal bursts on EEG, and also in the bursts with myoclonus.

CONCLUSION

The relation between the ictal activity of spasms and SB on EEG was shown to be close. The generative mechanisms of spasms and myoclonus might be linked to the bursting tendency intrinsic to immature brain function.

Secondary oxidation product on Si(111)-(7 x 7) characterized by isotope-labeled vibrational spectroscopy

The reaction of O(2) with Si(111)-(7 x 7) has been studied by electron energy-loss spectroscopy at 82 K. In addition to the losses due to Si-O-Si configurations, we observed two Si-O stretch modes depending on the coverage. A 146-meV peak appears at the initial reaction stage and was ascribed to a metastable product with one oxygen atom bonding on top of Si adatom and the other inserted into the backbond. The initial product is further oxidized to produce the second Si-O stretch peak at 150 meV. The secondary product was partially substituted with isotopes and analyzed with a simple model of coupled oscillators. The vibrational spectra reflect dynamical couplings between the isotopes, which is consistent with those predicted from the tetrahedral SiO(4) structure with one on top and three inserted oxygen atoms.

Deposition of 137Cs in Rokkasho, Japan and its relation to Asian dust

Biweekly atmospheric depositions of (137)Cs were measured in Rokkasho, Aomori, Japan from March 2000 to March 2006 to study recent (137)Cs deposition. Although the deposition level was generally lower than the detectable limit, deposition samples collected in spring occasionally had measurable levels of (137)Cs. The annual (137)Cs deposition from 2001 to 2005 was 0.04-0.69 Bq m(-2) with a mean value of 0.27 Bq m(-2). Depositions of insoluble Al, Fe and Ti were strongly correlated with the (137)Cs deposition, suggesting that suspension of soil particles was the main source of the recent (137)Cs deposition. Asian dust events were coincident with some of the significant (137)Cs depositions in spring. It was found that the ratios of (137)Cs/Al and Fe/Al could be used as indices for discriminating Asian dust from suspension of the local surface soil. Backward trajectory analysis suggested southern Mongolian and northeastern China regions as sources of the significant (137)Cs depositions.

Hypercalcemia in childhood acute lymphoblastic leukemia: frequent implication of parathyroid hormone-related peptide and E2A-HLF from translocation 17;19

Hypercalcemia is relatively rare but clinically important complication in childhood leukemic patients. To clarify the clinical characteristics, mechanisms of hypercalcemia, response to management for hypercalcemia, incidence of t(17;19) and final outcome of childhood acute lymphoblastic leukemia (ALL) accompanied by hypercalcemia, clinical data of 22 cases of childhood ALL accompanied by hypercalcemia (>12 mg/dl) reported in Japan from 1990 to 2005 were retrospectively analyzed. Eleven patients were 10 years and older. Twenty patients had low white blood cell count (<20 x 10(9)/l), 15 showed hemoglobin> or =8 g/dl and 14 showed platelet count > or =100 x 10(9)/l. Parathyroid hormone-related peptide (PTHrP)-mediated hypercalcemia was confirmed in 11 of the 16 patients in whom elevated-serum level or positive immunohistochemistry of PTHrP was observed. Hypercalcemia and accompanying renal insufficiency resolved quickly, particularly in patients treated with bisphosphonate. t(17;19) or add(19)(p13) was detected in five patients among 17 patients in whom karyotypic data were available, and the presence of E2A-HLF was confirmed in these five patients. All five patients with t(17;19)-ALL relapsed very early. Excluding the t(17;19)-ALL patients, the final outcome of ALL accompanied by hypercalcemia was similar to that of all childhood ALL patients, indicating that the development of hypercalcemia itself is not a poor prognostic factor.

Promoter polymorphism in the macrophage migration inhibitory factor gene is associated with obesity

OBJECTIVE

To explore the association of promoter polymorphisms of macrophage migration inhibitory factor (MIF) gene with obesity.

SUBJECTS

In total, 213 nondiabetic Japanese subjects. They were divided into three groups according to World Health Organization definitions: lean (body mass index (BMI) <25 kg/m2), overweight (25 < or = BMI < 30 kg/m2) and obese (BMI> or = 30 kg/m2).

METHODS

We examined two polymorphic loci in the MIF gene in the subjects: a single-nucleotide polymorphism at position -173 (G/C) and a CATT-tetranucleotide repeat polymorphism at position -794, which both can affect promoter activity in different cells.

RESULTS

We detected four alleles: 5-, 6-, 7- and 8-CATT at position -794. Genotypes without the 5-CATT allele (X/X, X refers to 6-, 7- or 8-CATT alleles) were more common in obese subjects than in lean or overweight groups (P = 0.013). The X-CATT allele was more frequent in obese subjects than in lean or overweight subjects (P = 0.030). In contrast, -173G/C was not associated with obesity. Among the haplotypes of the two promoter polymorphisms, G/5-CATT ((-173G/C)/(-794[CATT](5-8))) was associated with a decreased risk of obesity (P = 0.025) and G/6-CATT with an increased risk of overweight (P=0.028).

CONCLUSION

Promoter polymorphism in the MIF gene is linked with obesity.

Genetic linkage analysis of pulmonary fibrotic response to silica in mice

Inter-individual variations in the development of silicosis, even within the same environments, have been reported, which suggest the contribution of genetic factors in silicosis aetiology. The aim of the present study was to determine whether there is any significant genetic influence on the development of silicosis. Furthermore, which genetic loci are responsible for the pulmonary response to silica exposure? Eight strains of inbred mice were used to examine the genetic influence on the lung fibrotic response to silica exposure. After intercross-breeding between the most susceptible and most resistant strains, a genome-wide linkage analysis of quantitative trait loci (QTL) was performed. Hydroxyproline was applied as an index, and genotypes of 167 marker genes were analysed by fragment analysis using a capillary-type sequencer. There was significant inter-strain difference in the mean concentration of hydroxyproline contents among the eight strains of mice. Breeding studies were conducted between the most susceptible, C57BL/6J, and the most resistant strain, CBA/J. A genome-wide linkage analysis of silica-exposed intercrossed cohorts identified significant QTL on chromosome 4 and suggestive QTL on chromosomes 3 and 18. The present study demonstrates that genetic factors may play a significant role in fibrotic-lung responses to silica; one significant and two suggestive quantitative trait loci were identified.

Rapid Method for the Analysis of Plutonium Isotopes in a Soil Sample within 60 min

A rapid method for the determination of Pu isotopes in a soil sample within 60 min of starting sample pretreatment was developed. The large reduction in the analysis time was attained by the rapid and perfect digestion of the sample using an alkaline fusion method with an induction heating machine. Pu concentrations were then determined by flow injection/ICP-MS using a solid extraction resin after preconcentration by batch extraction with a chelate resin. The limits of detection for 239Pu and 240Pu were 9.2 fg and 4.3 fg, corresponding to 0.03 and 0.05 Bq kg(-1), respectively, under our analytical conditions, which satisfy the lower detection limits (0.5 Bq kg(-1) of 239Pu, and 2 Bq kg(-1) of 240Pu) required for rapid analysis techniques by the Ministry of Education, Culture, Sports, Science and Technology, Japan. This method provides a powerful and practical technique for emergency monitoring in and around nuclear facilities that handle large amounts of plutonium.

Immunological development of preterm infants in early infancy

To evaluate the immunological development of preterm infants, especially in early infancy, we examined the serum cytokine levels and the expression of Th2 and Th1 chemokine receptors, CCR4 and CCR5, on days 0, 14 and 28 in 16 low birth weight infants (1720.38 +/- 502.80 g) born at less than 37 (33.63 +/- 3.29) weeks of gestation. Using an enzyme-linked immunosorbent assay (ELISA), serum interleukin (IL)-4 levels exhibited an increase on day 14, but decreased to the initial level on day 28 (P < 0.05). The significant elevation of serum transforming growth factor (TGF)-beta levels was confirmed on day 14 (P < 0.05) but decreased to the initial level on day 28 (P < 0.05). The expression of CCR4 and CCR5 were examined using reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometric analysis. The RT-PCR confirmed the expression of CCR5-mRNA soon after birth, while there was no expression of CCR4-mRNA. Thereafter, the expression of CCR4-mRNA increased significantly and reached the level of CCR5-mRNA expression on day 28 (P < 0.05). Flow cytometric analysis, however, revealed that the expression levels of both CCR4 and CCR5 were low at birth. Thus, CCR4(+) CD4(+) cells were significantly increased from days 0-28 (P < 0.05), while CCR5(+) CD4(+) cells were not. Increased IL-4 and TGF-beta synthesis as well as increased CCR4(+) CD4(+) cells suggest that, under extra-maternal circumstances, there is a shift in bias toward Th2 responses even in preterm infants soon after delivery, while they may be capable of developing Th1 mediated responses soon after birth.

Development of Rapid Plutonium Analysis for Environmental Samples by Isotope Dilution/Inductively Coupled Plasma Mass Spectrometry with On-line Column

This paper describes our development of a rapid on-line column/ID-ICP-MS technique for the analysis of plutonium (Pu) in environmental samples using an UTEVA extraction chromatograph resin (UTEVA resin) column. It took only 40 min to separate and measure Pu in the sample solution, including the time for conditioning the resin column for the next analysis. In our method, Pu in a 3 M nitric acid solution was fed to the UTEVA resin, and then eluted from the resin by reducing Pu to Pu(III) with 3 M nitric acid mixed with 0.01 M ascorbic acid after washing the resin. The outflow from the resin column was directly introduced to an ICP-MS system. The low concentration of ascorbic acid and the small volume of the eluting solution (0.6 mL) made successive stable analysis possible without any skimmer cone clogging. The chemical recovery of Pu during column operation was 70%, and typical lower detection limits for 239Pu, 240Pu and 242Pu were 9.2, 4.3 and 7.5 fg (21, 36 and 1.1 microBq), respectively. We analyzed five international standard materials for Pu, and obtained good results.

Hyperbaric oxygenation therapy for simple adhesive postoperative intestinal obstruction in children: comparison of the use of a short tube versus a long tube

We hypothesized that hyperbaric oxygenation (HBO) combined with a long tube (LT) [HBO + LT] would be more effective than HBO combined with a short tube (ST) [HBO + ST] for simple adhesive postoperative intestinal obstruction (APIO) in children, assuming that there is synergism between HBO and LT. The objective of this study was to determine retrospectively the effect of HBO + LT compared to HBO + ST for simple APIO in children. Seventy-three patients were diagnosed with simple APIO, and 51 of these patients were treated with HBO + LT during 104 HBO sessions, while 22 were treated with HBO + ST during 34 HBO sessions. HBO was performed at a pressure of 2 atmospheres for 60 minutes once daily. The recovery rates after HBO therapy were 87.5 % for the HBO + LT group and 82.4 % for the HBO + ST group (p = 0.4496). HBO was performed 5 +/- 3 (range 1 to 15) times for the HBO + LT group and 4 +/- 2 (range 1 to 8) times for the HBO + ST group (p = 0.9847) for ultimate recovery from simple APIO. The recovery rate after HBO therapy of up to 6 sessions was 78.2 % for HBO + LT and 92.1 % for HBO + ST (p = 0.0360) among the cases that recovered ultimately. The effect of HBO + LT did not significantly differ from that of HBO + ST, but the insertion of an LT is more intricate and the cost is higher than that of an ST. Therefore, we conclude that the use of an LT is not necessarily required for HBO therapy for simple APIO.

Cytokines in the gastric mucosa of children with Helicobacter pylori infection

AIM

Few studies have looked at the cytokine profile in gastric mucosa in children with Helicobacter pylori infection. This study investigated cytokines and their effects on histological abnormalities in the gastric mucosa of children with H. pylori infection.

METHODS

The levels of interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and IL-8 proteins were measured in biopsy specimens from the gastric antrum and corpus of children with H. pylori infection, and related to inflammatory cell infiltrations.

RESULTS

The antral and corporal mucosal levels of IFN-gamma and IL-8 proteins were significantly higher in children with H. pylori infection than in uninfected children, but there was no such difference in the levels of IL-4 protein. The antral mucosal level of IL-8 protein was significantly higher than the corporal mucosal level of IL-8 protein in the infected children. Inflammatory cell infiltration was significantly higher in the infected children than in the uninfected children, but there were no significant correlations between mucosal cytokine levels and inflammatory cell infiltrations.

CONCLUSION

The results suggest that the predominant Th1 cytokine response and enhanced IL-8 production in the mucosa may be involved in the gastric inflammation seen in children infected with H. pylori, as well as in adult patients.