Evaluation of the nephrotoxicity and safety of low-dose aristolochic acid, extending to the use of Xixin (Asurum), by determination of methylglyoxal and d-lactate.

ETHNOPHARMACOLOGICAL RELEVANCE: Most Aristolochiaceae plants are prohibited due to aristolochic acid nephropathy (AAN), except Xixin (Asarum spp.). Xixin contains trace amounts of aristolochic acid (AA) and is widely used in Traditional Chinese Medicine. Methylglyoxal and d-lactate are regarded as biomarkers for nephrotoxicity. AIM OF THE STUDY: The use of Xixin (Asarum spp.) is essential and controversial. This study aimed to evaluate tubulointerstitial injury and interstitial renal fibrosis by determining urinary methylglyoxal and d-lactate after withdrawal of low-dose AA in a chronic mouse model. MATERIALS AND METHODS: C3H/He mice in the AA group (n = 24/group) were given ad libitum access to distilled water containing 3 µg/mL AA (0.5 mg/kg/day) for 56 days and drinking water from days 57 to 84. The severity of tubulointerstitial injury and fibrosis were evaluated using the tubulointerstitial histological score (TIHS) and Masson's trichrome staining. Urinary and serum methylglyoxal were determined by high-performance liquid chromatography (HPLC); urinary d-lactate were determined by column-switching HPLC. RESULTS: After AA withdrawal, serum methylglyoxal in the AA group increased from day 56 (429.4 ± 48.3 µg/L) to 84 (600.2 ± 99.9 µg/L), and peaked on day 70 (878.3 ± 171.8 µg/L; p < 0.05); TIHS and fibrosis exhibited similar patterns. Urinary methylglyoxal was high on day 56 (3.522 ± 1.061 µg), declined by day 70 (1.583 ± 0.437 µg) and increased by day 84 (2.390 ± 0.130 µg). Moreover, urinary d-lactate was elevated on day 56 (82.10 ± 18.80 µg) and higher from day 70 (201.10 ± 90.82 µg) to 84 (193.28 ± 61.32 µg). CONCLUSIONS: Methylglyoxal is induced after AA-induced tubulointerstitial injury, so methylglyoxal excretion and metabolism may be a detoxification and repair strategy. A low cumulative AA dose is the key factor that limits tubulointerstitial injury and helps to repair. Thus, AA-containing herbs, especially Xixin, should be used at low doses for short durations (less than one month).

Proteomics analysis of altered proteins in kidney of mice with aristolochic acid nephropathy using the fluorogenic derivatization-liquid chromatography-tandem mass spectrometry method.

Aristolochic acid (AA) causes interstitial renal fibrosis, called aristolochic acid nephropathy (AAN). There is no specific indicator for diagnosing AAN, so this study aimed to investigate the biomarkers for AAN using a proteomics method. The C3H/He female mice were given ad libitum AA-distilled water (0.5 mg/kg/day) and distilled water for 56 days in the AA and normal groups, respectively. The AA-induced proteins in the kidney were investigated using a proteomics study, including fluorogenic derivatization with 7-chloro-N-[2-(dimethylamino)ethyl]-2,1,3-benzoxadiazole-4-sulfonamide, followed by high-performance liquid chromatography analysis and liquid chromatography tandem mass spectrometry with a MASCOT database searching system. There were two altered proteins, thrombospondin type 1 (TSP1) and G protein-coupled receptor 87 (GPR87), in the kidney of AA-group mice on day 56. GPR87, a tumorigenesis-related protein, is reported for the first time in the current study. The renal interstitial fibrosis was certainly induced in the AA-group mice under histological examination. Based on the results of histological examination and the proteomics study, this model might be applied to AAN studies in the future. TSP1 might be a novel biomarker for AAN, and the further role of GPR87 leading to AA-induced tumorigenesis should be researched in future studies.

Cross-cultural variation of memory colors of familiar objects.

The effect of cross-regional or cross-cultural differences on color appearance ratings and memory colors of familiar objects was investigated in seven different countries/regions - Belgium, Hungary, Brazil, Colombia, Taiwan, China and Iran. In each region the familiar objects were presented on a calibrated monitor in over 100 different colors to a test panel of observers that were asked to rate the similarity of the presented object color with respect to what they thought the object looks like in reality (memory color). For each object and region the mean observer ratings were modeled by a bivariate Gaussian function. A statistical analysis showed significant (p < 0.001) differences between the region average observers and the global average observer obtained by pooling the data from all regions. However, the effect size of geographical region or culture was found to be small. In fact, the differences between the region average observers and the global average observer were found to of the same magnitude or smaller than the typical within region inter-observer variability. Thus, although statistical differences in color appearance ratings and memory between regions were found, regional impact is not likely to be of practical importance.

Chromaticity stability of phosphor-converted white light-emitting diodes with an optical filter.

The thermal stability of blue LEDs and yellow YAG phosphor for blue-pumped white LEDs is critical to the performance of white LEDs, including the color properties and luminous efficacy. To investigate the thermal effect on the color properties of emitted white light, the junction temperature of the excitation blue LED was raised by increasing the supplied current. However, by choosing an optical filter with the appropriate transmittance spectrum for processing a portion of the blue light output and reexciting the secondary yellow emission, we observed a reduction in color instability and lower color temperature across the current range of 20-200 mA. Moreover, the color temperature distribution was improved.