Elongation of seminal and lateral roots of rice seedlings was markedly inhibited by high ammonium levels in growth medium. However, high exogenous nitrate concentrations had little inhibitory effect on root growth. The objective of this study was to elucidate the relationship between inhibition of rice root growth induced by high ammonium conditions and ammonium assimilation in the seedlings. Activity of glutamine synthetase (GS) was kept at a low level in the seminal roots of the seedlings grown under high nitrate levels. In contrast, high ammonium levels significantly enhanced the GS activity in the roots, so that Gln abundantly accumulated in the shoots. These results indicate that ammonium assimilation may be activated in the seminal roots under high ammonium conditions. Application of methionine sulfoximine (MSO), an inhibitor of GS, relieved the repression of the seminal root elongation induced by high ammonium concentrations. However, the elongation of lateral roots remained inhibited even under the same condition. Furthermore, MSO drastically increased ammonium level and remarkably decreased Gln level in the shoots grown under high ammonium conditions. These results show that, for rice seedlings, an assimilatory product of ammonium, and not ammonium itself, may serve as an endogenous indicator of the nitrogen status involved in the inhibition of seminal root elongation induced by high levels of exogenous ammonium.

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cell tracking with magnetic resonance imaging (MRi) is important for evaluating the biodistribution of transplanted cells. Umbilical cord-derived mesenchymal stem cells (UC-MSCs) have emerged as a promising therapeutic tool in regenerative medicine. We examined the Uc-MScs labeled with superparamagnetic (Spio) and ultrasmall superparamagnetic iron oxide (USpio) in terms of cell functioning and imaging efficiency in vitro and in vivo. The UC-MSCs were co-incubated with SPIO or USPIO at a concentration of 50 or 100 µg/mL of label. Viability and proliferation were assessed by Trypan blue dye exclusion and MTT assay, respectively. Differentiation (chondrogenesis, osteogenesis, and adipogenesis) was induced to examine the impact of labelling on stemness. for in vitro experiments, we used 7-T MRI to assess the T 2 values of phantoms containing various concentrations of cell suspensions. For in vivo experiments, nine neonatal rats were divided into the control, SPIO, and USPIO groups. The UC-MSCs were injected directly into the rat brains. MRI images were obtained immediately and at 7 and 14 days post injection. The UC-MSCs were successfully labeled with SPIO and USPIO after 24 h of incubation. Cell viability was not changed by labelling. Nevertheless, labelling with 100 µg/mL USPIO led to a significant decrease in proliferation. The capacity for differentiation into cartilage was influenced by 100 µg/mL of SPIO. MRI showed that labeled cells exhibited clear hypointense signals, unlike unlabeled control cells. In the USPIO-labeled cells, a significant (P < 0.05) decrease in t 2 values (= improved contrast) was observed when compared with the controls and between phantoms containing the fewest and the most cells (0.5 × 10 6 versus 2.0 × 10 6 cells/mL). In vivo, the labeled cells were discernible on T 2-weighted images at days 0, 7, and 14. The presence of SPIO and USPIO particles at day 14 was confirmed by Prussian blue staining. Microscopy also suggested that the regions occupied by the particles were not as large as the corresponding hypointense areas observed on MRI. Both labels were readily taken up by the UC-MSCs and identified well on MRI. While SPIO and USPIO provide improved results in MRI studies, care must be taken while labelling cells with high concentrations of these agents. Mesenchymal stem cells (MSCs), a kind of somatic stem cells, are isolated from the mesenchymal tissues, such as fat, bone, and cartilage. MSCs can differentiate into mesodermal cells 1 , endodermal 2 , and ectodermal cells 3. Because of their regenerative and immunoregulatory capacities 4 , MSCs are expected to be applied for the therapy of various diseases, such as osteogenesis imperfecta, ischemic stroke, and cardiac infarction. Bone marrow is the most common source of MSCs. However, collecting MSCs from the bone marrow is highly invasive, and the maximal life span of the cells is affected by the donor's age 5. Currently, an umbilical cord tissue called Wharton's jelly is attracting attention, as a promising source of stem cells becaus...

CYFRA 21-1 is a fragment of cytokeratin 19 (CK 19). Four patients with large intrahepatic (or peripheral) cholangiocarcinoma (CC) and high serum levels of CYFRA 21-1 (normal, < or = 2 ng/ml) are reported. CYFRA 21-1 levels exceeded 9 ng/ml in all 4 patients. Carcinoembryonic antigen (CEA), was high in 1 (CEA; normal range, < or = 5.0 ng/ml) and carbohydrate antigen 19-9 (CA 19-9) was high in 3 (CA19-9; normal range, < or = 36 U/ml). We also measured serum levels of CYFRA 21-1 in 13 patients with hepatocellular carcinoma (HCC) more than 5 cm in diameter. Levels of CYFRA 21-1 exceeded 2 ng/ml in 9 of the HCC patients and were higher than 9 ng/ml in 2 of the HCC patients. Levels of alpha fetoprotein (AFP) and/or protein induced by vitamin K absence or antagonist II (PIVKA II) were elevated in all HCC patients (AFP, PIVKA II, respectively; normal range, < or = 10.0 ng/ml and < or = 0.1 AU/ml) CYFRA 21-1 levels were measured twice or three times during the clinical course in 2 CC patients and in 6 HCC patients, and increased gradually with tumor growth in the 2 CC patients and in 3 of the 6 HCC patients. Marked increases in serum CYFRA 21-1 levels in patients with large liver cancers, particularly in those with normal levels of AFP and PIVKA II, would suggest the existence of intrahepatic CC rather than HCC.

The purpose of this study was to evaluate the effectiveness of intracellular magnetic hyperthermia treatment (MHT) in comparison with that of extracellular MHT using magnetic particle imaging (MPI). Colon-26 cells were implanted subcutaneously into the backs of 8-week-old male BALB/c mice. When the tumor volume reached approximately 100 mm 3 , the mice were divided into control (n = 10), extracellular MHT (n = 8), and intracellular MHT groups (n = 7). In the control group, MHT was not performed. In the extracellular MHT and intracellular MHT groups, the tumors were injected directly with magnetic nanoparticles (MNPs) (400 mM Resovist®) and were heated for 20 min using an alternating magnetic field. During MHT, the temperatures of the tumor and rectum were measured using optical fiber thermometers. In the extracellular MHT group, MHT was performed 15 min after the injection of MNPs, whereas MHT was performed one day after the injection of MNPs in the intracellular MHT group. In both groups, MPI images were obtained using our MPI scanner immediately before, immediately after, and 7 and 14 days after MHT. After the MPI studies, we drew a region of interest (ROI) on the tumor in the MPI image and calculated the average, maximum, and total MPI values and the number of pixels within the ROI. Transmission electron microscopic (TEM) images were also obtained from resected tumors. In all groups, tumor volume was measured every day and the relative tumor volume growth (RTVG) was calculated. The TEM images showed that almost all the MNPs were aggregated in the extracellular space in the extracellular MHT group, whereas they were contained within the intracellular space in the intracellular MHT group. Although the temperature of the tumor in the intracellular MHT group was significantly lower than that in the extracellular MHT group, the RTVG value in the intracellular MHT group was significant- ly lower than that in the control group 2 days or more after MHT and that in the extracellular MHT group 3, 4, and 5 days after MHT. The average MPI value normalized by that immediately before MHT in the intracellular MHT group was significantly higher than that in the extracellular MHT group immediately and 7 days after MHT. The maximum and total MPI values normalized by those immediately before MHT in the intracellular MHT group were significantly higher than those in the extracellular MHT group 7 days after MHT, suggesting that the temporal change of MNPs within the tumor in the intracellular MHT group was smaller than that in the extracellular MHT group. Our results suggest that intracellular MHT is more cytotoxic than extracellular MHT in spite of a lower temperature rise of tumors, and that MPI is useful for evaluating the difference in the temporal change of MNPs in the tumor between extracellular MHT and intracellular MHT.

This study aimed to evaluate the effect of chemical exchange saturation transfer (CEST) on the ischemic regions in hypoxic-ischemic encephalopathy (HIE) in comparison with diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) using a 7T-MRI. Methods: We used neonatal rats (n = 8), aged 8 days, to clarify the progression of HIE. The rat model of HIE was developed by ligating and severing the left common carotid artery, followed by 45 minutes of recovery, and 60 minutes of hypoxia (8% O 2 /92% N 2 ; 34°C). At 0-2 and 24 hours after the onset of HIE, CEST imaging, DWI, and MRS were performed with a 7T-MRI. The magnetization transfer ratio (MTR) asymmetry curves and four MTR asymmetry maps at 0.5, 1.0, 2.0, and 3.5 ppm were calculated using the CEST images. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) maps were calculated by DWI, and brain metabolites were assessed by MRS. Results: In the ischemic regions of neonatal rats, FA was significantly increased at 0-2 hours and decreased at 24 hours after the onset of HIE. ADC in the ipsilateral side was significantly lower than that of contralateral side. All rats with HIE showed hypointense areas on MTR asymmetry maps (2.0 and 3.5 ppm), that did not correspond with the hyperintense areas on DWI. In addition, a significant increase in lactate levels was observed at 0-2 and 24 hours after the onset of HIE. Conclusion: CEST MTR maps did not correspond with the hyperintense areas on DWI at 0-2 and 24 hours after the onset of HIE. The change of multi offset CEST signal may be primarily related to the brain metabolites and pH alterations, such as that caused by lactate, after the onset of HIE.

Purpose: Magnetic targeting refers to the attachment of therapeutic agents to magnetizable particles such as magnetic nanoparticles (MNPs) and then applying magnetic fields to concentrate them to the targeted region such as solid tumors. The purpose of this study was to investigate the usefulness of magnetic particle imaging (MPI) for monitoring the effect of magnetic targeting using tumor-bearing mice. Materials and Methods: Colon-26 cells (1 × 10 6 cells) were implanted into the backs of eight-week-old male BALB/c mice. When the tumor volume reached approximately 100 mm 3 , the mice were divided into treated (n = 8) and untreated groups (n = 8). The tumors in the treated group were directly injected with MNPs (Resovist ® , 250 mM) and a neodymium magnet was attached to the tumor surface, whereas the magnet was not attached to the tumor in the untreated group. The mice were imaged using our MPI scanner and the average and maximum MPI values were obtained by drawing a region of interest (ROI) on the tumor, with the threshold value for extracting the contour of the tumor being taken as 40% of the maximum MPI value in the ROI. The relative tumor volume growth (RTVG) was calculated from (V − V0)/V0, where V0 and V represented the tumor volume immediately before and after the injection of MNPs, respectively. Results: The average and maximum MPI values in the treated group were significantly higher than those in the untreated group 3 days after the injection of MNPs, suggesting the effectiveness of magnetic targeting. There were no significant differences in RTVG between the two groups. Conclusion: Our preliminary results suggest that MPI is useful for monitoring the effect of magnetic targeting.