Morio Shimada

Anti-Hypertensive Effect of γ-Aminobutyric Acid (GABA)-Rich Chlorella on High-Normal Blood Pressure and Borderline Hypertension in Placebo-Controlled Double Blind Study

The anti-hypertensive effect of GABA-rich Chlorella was studied after oral administration for 12 weeks in the subjects with high-normal blood pressure and borderline hypertension in the placebo-controlled, double-blind manner in order to investigate if GABA-rich Chlorella, a dietary supplement, is useful in control of blood pressure. Eighty subjects with Systolic blood pressure (SBP) 130–159 mmHg or diastolic blood pressure (DBP) 85–99 mmHg (40 subjects/group) took the blinded substance of GABA-rich Chlorella (20 mg as γ-aminobutyric acid) or placebo twice daily for 12 weeks, and had follow-up observation for an additional 4 weeks. Systolic blood pressure in the subjects given GABA-rich Chlorella significantly decreased compared with placebo (p < 0.01). Diastolic blood pressure had the tendency to decrease after intake of GABA-rich Chlorella. Neither adverse events nor abnormal laboratory findings were reported throughout the study period. Reduction of SBP in the subjects with borderline hypertension was higher than those in the subjects with high-normal blood pressure. These results suggest that GABA-rich Chlorella significantly decreased high-normal blood pressure and borderline hypertension, and is a beneficial dietary supplement for prevention of the development of hypertension.

Evaluation of gadoxetate disodium as a contrast agent for mouse liver imaging : comparison with gadobenate dimeglumine

We investigated the characteristics of gadoxetate disodium (Gd-EOB-DTPA) as a contrast agent for magnetic resonance imaging of the mouse liver. Mice were imaged sequentially under isoflurane anesthesia using a T1-weighted, three-dimensional fast low-angle shot (3D FLASH) sequence after an intravenous injection of Gd-EOB-DTPA or gadobenate dimeglumine (Gd-BOPTA), and the time course of the contrast effect was examined. The time course of the contrast effect of Gd-EOB-DTPA was also assessed after intravenous injection under pentobarbital anesthesia and after subcutaneous injection while awake or under isoflurane or pentobarbital anesthesia. Moreover, different doses of Gd-EOB-DTPA or Gd-BOPTA were injected subcutaneously into conscious mice, and the clarity of the liver border was evaluated visually. Intravenous injection under isoflurane anesthesia caused rapid contrast enhancement in the liver with both Gd-EOB-DTPA and Gd-BOPTA, and the contrast effect was 41% stronger with Gd-EOB-DTPA. Subcutaneous injection of Gd-EOB-DTPA caused delayed but favorable contrast enhancement in the liver. Washout of Gd-EOB-DTPA was faster in mice injected while awake than in those injected under anesthesia. After intravenous injection, washout was faster under pentobarbital anesthesia than under isoflurane anesthesia. The peak liver contrast was 11% and 18% stronger under pentobarbital anesthesia than under isoflurane anesthesia, after intravenous and subcutaneous injections, respectively. Subcutaneous injection of Gd-EOB-DTPA or Gd-BOPTA caused dose-dependent contrast effects in the liver. At a given dose, the contrast effect tended to be stronger and liver demarcation tended to be clearer with Gd-EOB-DTPA than with Gd-BOPTA. In conclusion, intravenous or subcutaneous injection of Gd-EOB-DTPA produces a favorable contrast effects in the mouse liver, indicating its potential in investigating mouse models of liver diseases. The contrast effects vary between conscious mice and anesthetized mice and among anesthetic agents used.

Interstitial magnetic resonance lymphography: comparative animal study of gadofluorine 8 and gadolinium diethylenetriamine-pentaacetic acid.

Purpose We evaluated the usefulness of gadofluorine 8 (G8) and gadolinium diethylenetriamine-pentaacetic acid (Gd-DTPA) for interstitial magnetic resonance lymphography (MRL). Method Phantom imaging studies were conducted with G8 and Gd-DTPA corresponding to 0.1–0.005 &mgr;mol Gd/mL, and signal intensity was measured. Popliteal lymph node (PLN) accumulation was investigated in rabbits. Imaging was performed before and after subcutaneous administration of G8 (50 &mgr;mol Gd/mL) and Gd-DTPA (50 &mgr;mol Gd/mL). Contrast enhancement ratio measurements of PLN were determined both prior to and following the administration. Results Signal intensity of phantom for G8 are higher than those for Gd-DTPA from 0.1 to 0.002 &mgr;mol Gd/mL (P < 0.0001). Imaging after 5 minutes can clearly detect PLN accumulation on two contrast agents. Nevertheless, PLN accumulation of Gd-DTPA disappeared after about 30 minutes. A statistically significant difference between G8 and Gd-DTPA can be seen from 5 to 90 minutes in CER (P < 0.0001). PLN became clearly visible at 5 minutes after the injection of G8 and Gd-DTPA. Nevertheless, PLN accumulation of Gd-DTPA disappeared at 30 minutes. Otherwise, PLN accumulation of G8 continued up to 90 minutes. Conclusion These studies indicated that G8 was more suitable than Gd-DTPA as a contrast agent for interstitial MRL up to 90 minutes.

Diet and gastrointestinal signal on T1-weighted magnetic resonance imaging of mice.

In magnetic resonance (MR) imaging of small animals, the gastrointestinal contents may give rise to intense signals on T1-weighted images. The aim of this study was to determine the optimal dietary preparation to reduce gastrointestinal signals in mice and to evaluate the usefulness of this approach. Images of the mouse trunk were obtained using a T1-weighted, three-dimensional fast low-angle shot sequence under various dietary conditions and were compared with respect to the gastrointestinal signals and image quality. The dietary preparation studied included giving alternative diets for 24 h, intestinal cleansing, and 6-h fasting. Mice with and without dietary preparation underwent MR lymphography using gadofluorine 8, and the visualization of abdominal lymph nodes was compared. In the absence of dietary preparation, hyperintense areas were conspicuous in the gastrointestinal system, whereas on the images taken from mice fed potato or sweet potato for 24 h before imaging, gastrointestinal hyperintensity was less prominent. This preparation also reduced artifactual signals and resulted in higher-quality images of the kidneys. Intestinal cleansing, which consisted of 24-h fasting and laxative intake, did not reduce the gastrointestinal signals and caused signal changes that were indicative of fatty liver development. Some of the abdominal lymph nodes of the mice that did not receive dietary preparation were visualized on MR lymphography source images but not on maximum intensity projection (MIP) images. In contrast, on the MIP images of mice fed potato, all the lymph nodes delineated on the source images were successfully visualized. In conclusion, feeding mice potato or sweet potato for 24 h before MR imaging reduces the gastrointestinal signals and image degradation due to artifacts. Appropriate dietary preparations facilitate the display of target structures on MIP images and are expected to enhance the capabilities of small animal MR imaging.

Phantom and animal studies of a new hepatobiliary agent for MR imaging: Comparison of Gd-DTPA-DeA with Gd-EOB-DTPA

To investigate the characteristics of Gd‐DTPA‐DeA as a hepatobiliary contrast agent for MR imaging in comparison with those of Gd‐EOB‐DTPA.

Integrated Lymphography Using Fluorescence Imaging and Magnetic Resonance Imaging in Intact Mice

We assessed lymph drainage in living mice by an integrated imaging method using fluorescence imaging (FLI) and magnetic resonance imaging (MRI). Mice were subcutaneously injected with quantum dots and gadofluorine 8 into the right rear footpad. They were fixed on a transparent flat plate and underwent FLI and MRI successively. Small markers were attached to the mouse surface for spatial coregistration, and image fusion of FLIs and MRIs was performed. Two-dimensional fluorescence reflectance imaging was used for FLI. FLI and MRI provided generally consistent results and demonstrated lymphatic flow to the popliteal, sacral, and iliac lymph nodes in most mice and to the renal, inguinal, and lumbar-aortic lymph nodes in some mice. On the fusion images, the locations of the lymph nodes in the mouse trunk were in good agreement between FLI and MRI, indicating successful spatial registration even for the deep structures. The popliteal node tended to be visualized a little farther caudally in FLI than in MRI, presumably because the overlying tissues were thicker in the cranial portion. Integrated FLI/MRI lymphography with image fusion appears to be a useful tool for analysis of the murine lymphatic system.

Development of the Press-Through Package Recognizable with Abdominal X-Ray Image of Abdominal Soft Tissue Phantom

Background: Patients with dementia who accidentally swallowed a press- through package (PTP) have been increased in recent years. Swallowed PTP is usually detected with CT having a risk of radiation exposure since PTP is very difficult to detect with abdominal X-ray image. Purpose: This study is aimed at developing the new PTP sheet recognizable with abdominal X-ray by improving the conventional PTP sheet. Material and Methods: The PTP sheet samples used in this study are: No. 1 Control: Commercially available tablet 100 mg, No. 2 Triple-stacked aluminum foil, 6-overcoated with BaSO4 10.3 g/m2, No. 3 Aluminum foil, 6-overcoated with BaSO4 10.3 g/m2, No. 4 Five-stacked aluminum foil, 6-overcoated with BaSO4 No. 5 Aluminum foil, single-coated with WO3 2.55 g/m2, No. 6 Aluminum foil, double-coated with WO3 5.1 g/m2, No. 7 Aluminum foil, triple-coated with WO3 7.66 g/m2, No. 8 Three-stacked aluminum foil, triple-coated with WO3. PTP sheets (No. 1 - No. 8) were placed inside the abdominal soft tissue phantom, and the images were obtained using FUJIFILM DR CALNEO PT. Region of interest (ROI) was placed on PTP sheets (No. 1 - No. 8) and abdominal soft tissue liquid phantom, and each contrast was measured from the average pixel of the two ROIs. Contrast was calculated by the calculation formula. Each ROI was measured three times, and their average value and standard deviation were estimated. Results: Statistical significance in contrast was not observed in commercial PTP sheet (No. 1), PTP sheet (No. 3), and PTP sheet (No. 5), while there was a significant difference between PTP sheet (No. 1) and PTP sheet (No. 2), PTP sheet (No. 4) PTP sheet (No. 6), PTP sheet (No. 7) (p 4 is considered to be more suitable than PTP sheets of WO3 (No. 6, No. 7, No. 8) because it is easier to produce. We will develop oral PTP sheets for patients with dementia for abdominal X-ray in the future.

Computer-assisted esophageal wall motion analysis from digital fluoroscopic images

The dynamic image recognition is applied to the robot engineering sciences. This technology (the optical flow method) was used the computer aided diagnosis of the esophageal fluoroscopy. The dynamic images were obtained by means of using digital video recorder. The motion vectors are calculated using the computer vision algorithm (the gradient based method) from these dynamic images in each pixels. The motion vectors were visualized in color images and allow images. The results showed that the motion of normal esophageal walls were manly in the horizontal direction, whereas a large oblique direction component was observed in that of abnormal esophageal walls. The dynamic image recognition was useful in clinical study for the analysis of esophageal wall motion.