A pulsed neutron transmission coupled with a two-dimensional position sensitive neutron detector gives a time-of-flight spectrum at each pixel of the detector, which depends on the total ...cross-sections of materials. In order to extract quantitative information of the preferred orientation included in the Bragg scattering total cross-section data, a spectral analysis software for the 2D imaging has been developed, and the transmission data of an unbent iron plate were analyzed. The 2D images with respect to the preferred orientation were successfully obtained, and the effectiveness of spectroscopic neutron transmission imaging was indicated.
Human pentavalent arsenic metabolic intermediate, monomethylarsonic acid (MMAs
V), is a major arsenic type found in the blood in chronic arsenic poisoning patients, but little information is ...available on its toxicity potential or mechanisms of action. In this study, we investigated the molecular mechanisms of in vitro cytolethality of MMAs
V using rat liver TRL 1215 cells. Cellular arsenic concentrations reached the nanomolar range in TRL 1215 cells when cells were exposed to millimolar levels of MMAs
V, and most of the MMAs
V was not metabolized during the 48-h incubation. Under these conditions, MMAs
V showed significant cytolethality when cellular reserves of reduced glutathione (GSH) were depleted. Morphological and biochemical evidence confirmed that MMAs
V induced both necrosis and apoptosis in the cellular GSH-depleted cells. MMAs
V significantly enhanced cellular caspase 3 activity in the cellular GSH-depleted cells, and a caspase 3 inhibitor blocked MMAs
V-induced apoptosis. MMAs
V also enhanced the production of cellular reactive oxygen species (ROS) in the cellular GSH-depleted cells, and addition of a membrane-permeable radical trapping reagent completely prevented both MMAs
V-induced cellular caspase 3 activation and cytolethality in these cells. These observations suggest that MMAs
V typically generates harmful ROS in cells, and cellular GSH prevents cytolethality by scavenging these toxic ROS. However, when cellular GSH levels are decreased, MMAs
V induces oxidative stress in the cells, and this leads to apoptosis and/or necrosis depending on the cellular ROS/GSH ratio.
Inorganic arsenicals are clearly toxicants and carcinogens in humans. In mammals, including humans, inorganic arsenicals often undergo methylation, forming compounds such as dimethylarsinic acid ...(DMAs
V). Recent evidence indicates that DMAs
V is a complete carcinogen in rodents although evidence for inorganic arsenicals as carcinogens in rodents remains equivocal. Thus, we studied the molecular mechanisms of in vitro cytolethality of DMAs
V using a rat liver epithelial cell line (TRL 1215). DMAs
V selectively induced apoptosis in TRL 1215 cells; its LC
50 value after 48 h exposure was 4.5 mM. The addition of a glutathione synthase inhibitor, L-buthionine-
S,R-sulfoximine (BSO), actually decreased DMAs
V-induced apoptosis. DMAs
V exposure temporarily decreased cellular reduced glutathione (GSH) levels and enhanced cellular glutathione
S-transferase (GST) activity from 6 h after the exposure when the cells were still alive. Also, DMAs
V exposure activated cellular caspase 3 activity with a peak at 18 h after the exposure when apoptosis began, and BSO treatment completely inhibited this enzyme activity. The additions of inhibitors of caspase 3, caspase 8, and caspase 9 significantly reduced DMAs
V-induced apoptosis. Taken together, these data indicate that cellular GSH was required for DMAs
V-induced apoptosis to occur, and activation of cellular caspases after conjugation of DMAs
V with cellular GSH appears to be of mechanistic significance. Further research will be required to determine the role of intracellular GSH and methylation in the toxicity of arsenicals in chronic arsenic poisoning or in cases where arsenicals are used as chemotherapeutics.
A spectroscopic neutron imaging is attractive in the research field of energy-selective neutron radiography. Imaging using the time-of-flight (TOF) method at a pulsed neutron source is very suitable ...for such spectroscopic measurements. We developed new two-dimensional position sensitive neutron detectors (2D-PSNDs) aiming at high detection efficiency, high counting rate and high time resolution which are the most important 2D-PSND performances for the spectroscopic imaging. These detectors consist of independent 6Li-glass (Ce) scintillator pixels, and have been used in various pulsed neutron transmission experiments. As a result, we have succeeded in developing various new imaging techniques; crystallographic, nuclide-selective and thermographic imaging.
An end-to-end delay analysis method is proposed for the datacenter network, the topology of which is N-stage tandem LAN switches with variable bandwidth links. According to the characteristics of ...burst (ON/OFF) traffic in the datacenter network, the arrival traffic to the switches is modeled as a series of rectangular traffic elements. By analyzing the queue-size behaviors of the N-stage switches, the transient behavior of the end-to-end delay can be obtained deterministically and accurately and expressed as a concatenation of a linear function of time t. The proposed analysis method is verified by comparing results of both an analysis and a simulation.
A 46-year-old man who had been treated with azathioprine (150 mg/day) and prednisolone (7.5-10 mg/day) for 16 years after allogeneic renal transplantation was admitted to our hospital in July 1996 ...for evaluation of pancytopenia. Three years earlier he had been given a diagnosis of renal pelvic and ureteral cancer, and underwent left nephrectomy with total uretectomy. His bone marrow was normocellular with excess of blasts (27.6%), and displayed trilineage myelodysplasia. A chromosomal analysis of the bone marrow revealed 43-45, XY with del (1) (p13), -5, del (7) (q22), -17, -18, and -19. The patient was given a diagnosis of refractory anemia with excess of blasts in transformation (RAEB in T), and treated with idarubicin and cytosine arabinoside. Two months later, overt acute leukemia developed and reinduction chemotherpay was started, but the patient died of cerebral hemorrhage in October. This case suggests that immunosuppressive agents such as azathioprine might play an important role in the pathogenesis of MDS (RAEB in T) and renal pelvic and ureteral cancer after renal transplantation.
This report details a case of infection associated hemophagocytic syndrome (IAHS). A 20-year-old female was admitted to our hospital with persistent high fever in July, 1994. Physical examination ...revealed high body temperature (40 degrees C), marked hepatosplenomegaly and no superficial lymph node swelling. Laboratory examination revealed leukopenia and abnormal liver function on admission. Serum ferritin levels were surprisingly elevated. The coagulation tests showed high FDP and D-dimer. Specific viral antibody titers were not elevated such as Epstein-Barr virus or Cytomegalovirus. Bone marrow examination revealed histiocytic hyperplasia with hemophagocytosis, and the histiocytes were well matured. We diagnosed IAHS. Corticosteroids were administered on the 3rd hospital day (methylprednisolone 1 g/day, 3 days), but persistent high fever and laboratory findings did not improve. So we tried etoposide (etoposide 200 mg/day, 5 days) therapy on the 13th hospital day. After administration of etoposide, she failed to recover from severe leukopenia and suffered from meningitis. We administered G-CSF, gamma-globulin and antibiotics for intensive supportive therapy. As the leukocyte count increased, her symptoms and laboratory data improved. There was no hemophagocytosis in her bone marrow before discharge. Recently, etoposide is said to be effective for reactive monocytic proliferation. Administration of etoposide was very effective for IAHS, although corticosteroids, were ineffective.
The Bragg-edge positions of an annealed sample correspond to those of a cast sample whilst the total cross section of an annealed sample is smaller than that of a cast sample. The total cross section ...may be influenced by the crystallite size and extinction. Multiple scattering will occur in the same crystal grain if the crystallite size is large. The extinction seems to increase with increasing crystallite size. Powdered Si is prepared by rushing the single crystal of Si, so that the grain size agrees with the crystallite size. Si was sieved to get grain sizes about 2.7 mum, 100 mum and 200 mum, respectively. The Bragg-edge positions among the three samples are the same. The total cross section decreases with increasing crystallite size. It is found that the total cross section depends on the crystallite size and the extinction is one factor to decrease the value of the total cross section. Bragg-edge neutron transmission is a useful tool as a nondestructive test.
Disseminated intravascular coagulation (DIC) is one of the most critical complications of malignant diseases. It is conventionally diagnosed by a decrease in platelets and an increase in ...fibrin/fibrinogen degradation products (FDP). Recently, an immunological assay was developed that can directly quantify the amount of soluble fibrin (SF) formed in the blood. This study examined this assay system in the diagnosis of DIC and found that it is a good indicator of both fibrin formation and of DIC. Plasma levels of SF correlated well with the DIC score, which is determined according to the 'DIC Scoring Guideline' proposed by the DIC Study Group under the Japanese Ministry of Public Welfare in 1988. It also correlated well with the serum levels of FDP. Normal values of plasma SF ranged between 0 and 9.50 micrograms/ml. Interestingly, values of SF in females tended to increase with age, for reasons that are not yet determined.
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