Effect of palmitoylethanolamide on degeneration of a human-derived retinal pigment epithelial cell induced by all-trans retinal.

AIM: To study the effect of palmitoylethanolamide (PEA) on apoptosis of retinal pigment epithelial (RPE) cells induced by all-trans retinal (atRAL) and to explore the possible molecular mechanism. METHODS: CellTiter 96® Aqueous One Solution Cell Proliferation Assay (MTS) was used to detect the effect of PEA on human-derived retinal epithelial cells (ARPE-19) viability induced by atRAL. A Leica DMi8 inverted microscope was used to observe cell morphology. Reactive oxygen species (ROS) production was evaluated with 2',7'-dichlorodihydrof-luorescein diacetate (H2DCFDA) staining and fluorescence microscopy. Expression of c-Jun N-terminal kinase (JNK), phosphorylated JNK (p-JNK), c-Jun, phosphorylated c-Jun (p-c-Jun), Bak, cleaved caspase-3, C/EBP homologous protein (CHOP), and binding (Bip) protein levels were tested by Western blot. Abca4 -/- Rdh8 -/- mice, mouse models of atRAL clearance defects which displays some symbolic characteristics of dry age-related macular degeneration (AMD) and Stargardt disease (STGD1). In the animal models, PEA was injected intraperitoneally. The full-field electroretinogram was used to detect visual function under scotopic conditions traced from mice. Optical coherence tomography showed reconstitution or thickening of the retinal pigment epithelium layer. Effect of PEA on fundus injury induced by light in Abca4-/-Rdh8-/- mice was observed by fundus photography. RESULTS: PEA ameliorated ARPE-19 cells apoptosis and inhibited ROS (including mitochondrial ROS) production induced by atRAL. PEA improved the retinal functional, prohibited both RPE and photoreceptor from death, ameliorates light-induced fundus impairment in Abca4 -/- Rdh8 -/- mice. In vitro and in vivo, PEA inhibited JNK, p-JNK, c-Jun, p-c-Jun, Bak, cleaved caspase-3, CHOP, and Bip protein levels induced by all-trans retinal in ARPE-19 cells. CONCLUSION: PEA has effect on treating RPE cells apoptosis in retinopathy caused by atRAL accumulation. PEA is a potential treatment strategy for dry AMD and STGD1. The molecular mechanism is affecting the ROS-JNK-CHOP signaling pathway partly.

All-trans-retinoic acid generation is an antidotal clearance pathway for all-trans-retinal in the retina.

The present study was designed to analyze the metabolites of all-trans-retinal (atRal) and compare the cytotoxicity of atRal versus its derivative all-trans-retinoic acid (atRA) in human retinal pigment epithelial (RPE) cells. We confirmed that atRA was produced in normal pig neural retina and RPE. The amount of all-trans-retinol (atROL) converted from atRal was about 2.7 times that of atRal-derived atRA after incubating RPE cells with 10 µmol/L atRal for 24 h, whereas atRA in medium supernatant is more plentiful (91 vs. 29 pmol/mL), suggesting that atRA conversion facilitates elimination of excess atRal in the retina. Moreover, we found that mRNA expression of retinoic acid-specific hydroxylase CYP26b1 was dose-dependently up-regulated by atRal exposure in RPE cells, indicating that atRA inactivation may be also initiated in atRal-accumulated RPE cells. Our data show that atRA-caused viability inhibition was evidently reduced compared with the equal concentration of its precursor atRal. Excess accumulation of atRal provoked intracellular reactive oxygen species (ROS) overproduction, heme oxygenase-1 (HO-1) expression, and increased cleaved poly(ADP-ribose) polymerase 1 (PARP1) expression in RPE cells. In contrast, comparable dosage of atRA-induced oxidative stress was much weaker, and it could not activate apoptosis in RPE cells. These results suggest that atRA generation is an antidotal metabolism pathway for atRal in the retina. Moreover, we found that in the eyes of ABCA4-/-RDH8-/- mice, a mouse model with atRal accumulation in the retina, the atRA content was almost the same as that in the wild type. It is possible that atRal accumulation simultaneously and equally promotes atRA synthesis and clearance in eyes of ABCA4-/-RDH8-/- mice, thus inhibiting the further increase of atRA in the retina. Our present study provides further insights into atRal clearance in the retina.

[Distribution and Burial Characteristics of Nitrogen Forms in Sediment of Dianchi Lake During Last Century].

In order to analyze the composition, distribution and burial characteristics of nitrogen in sediments of Dianchi Lake in the last hundred years, 6 sediment cores were sampled in July 2014 to determine the contents of different nitrogen species and sedimentary age sequence. The integrated results demonstrated a high content of total nitrogen in sediments ranging from 1263.68-7155.17 mg·kg-1. The contents of nitrate nitrogen and ammonium nitrogen were low, which were 10.00-144.00 mg·kg-1and 9.20-146.50 mg·kg-1, respectively. Organic nitrogen was the main component in the sediments, ranging from 255.80 to 5644.25 mg·kg-1, composing a large average percentage of 91.26%. In addition, the nitrogen pollution of sediment in Dianchi Lake has reached a high level and is becoming serious since 1970s, which surged in the late 1990s. The spatial difference of total nitrogen was obvious, with comparably the most in the south, less in the north and least in the center. The average deposition rate was changing from 0.092 g·(cm2·a)-1 to 0.187 g·(cm2·a)-1 in the last 100 years and increased first, then declined, finally showed a slight upward trend over time. The burial rate of total nitrogen in sediment increased over time and almost grew up straightly after 1990,which decreased from the south to the north of Dianchi Lake in space. It was estimated that the reserves of total nitrogen, organic nitrogen, nitrate nitrogen, ammonium nitrogen in the sediment were 92139.15 t, 86745.62 t, 2464.16 t, 2929.37 t, respectively, from 1900 to 2014.

[Distribution Characteristics of n-alkanes in Sediment Core and Implication of Environment in Different Lakes of Dianchi].

In order to study the composition and environment significance of the organic matter in Lake Dianchi, samples from two sediment cores from the northern and southern parts of the lake were collected in July, 2014. Meanwhile, the vertical distributions of total organiccarbon (TOC), total nitrogen (TN), n-alkanes fractions were investigated. The results showed that ① the concentrations of TOC and TN had been clearly increasing since the 1970s, which implied that the primary productivity of Lake Dianchi was continuously enhanced; ② The values of the parameter n-C27/n-C31, Paqand CPI indicated the alternation between herbs and woody plants from the bottom up in Lake Dianchi sediments. Besides, the high carbon number of organic matter in sediments mainly originated from endogenous submerged floating and large plants; ③ The index of C/N and distribution characteristics of n-alkanes suggested differences in the various sources of organic matter in different lakes. In detail, organic matter came from terrigenous organic matter of anthropogenic sources and endogenous bacteria in the sediments of northern Dianchi, while organic matter was derived from endogenous aquatic and terrestrial higher plants mixed source in the sediments of southern Dianchi. Finally, it is worthwhile to emphasize further research on organic matter in different lakes of Lake Dianchi.

[Adsorption and Desorption Characteristics of Endosulfan in Purple Soil].

In order to reveal the residual process of endosulfan in purple soil and protect soil ecological environment, the adsorption and desorption characteristics of endosulfan in purple soil were investigated, and effects of temperature, adsorbent amount, and initial pH of adsorption solution on the adsorption capacity were also examined by static adsorption and desorption experiments. The results showed that the adsorption kinetic process could be well described by the second-order kinetic equation with the initial rate constants of α-, ß-endosulfan as 0. 157 and 0. 115 mg.(g.min)-1, respectively. The adsorption thermodynamic process could be well described by the Langmuir isotherm with the maximum adsorption capacities of α-, ß-endosulfan as 0. 257 mg . g -1 and 0. 155 mg . g -1, respectively. The adsorption process of endosulfan in purple soil may be an exothermic physicochemical process, and is dominated by physical adsorption. Under the experimental conditions examined in this study, the initial pH of adsorption solution had a relative great influence on the adsorption capacity, whereas the temperature and adsorbent amount had no significant influence. The desorption experiments found that the maximum desorption capacities of α-, ß-endosulfan adsorbed in purple soil were 0. 029 mg . g -1 and 0. 017 mg . g -1 at 6 and 4 h, and accounted for 10. 5% and 16. 1% in the maximum adsorption capacities, respectively.

Effects of organic solvents on two retinal pigment epithelial lipofuscin fluorophores, A2E and all-trans-retinal dimer.

Gene and drug therapies are being developed to alleviate vision loss in patients with Stargardt's disease and age-related macular degeneration (AMD). To evaluate the therapeutic effects of these treatments, organic solvents are routinely used to extract and quantify bisretinoid lipofuscin constituents, such as N-retinylidene-N-retinyl-ethanolamine (A2E) and all-trans-retinal dimer (ATR-dimer). By high-performance liquid chromatography (HPLC), we found that A2E and ATR-dimer were both altered by tetrahydrofuran (THF) and chloroform, but were stable in dimethyl sulfoxide (DMSO) or methanol (MeOH). In addition, cyclohexane and ethanol (EtOH) did not alter ATR-dimer, whereas an alteration of A2E occurred in EtOH. On the basis of these findings, we designed processes II-IV, generated by modifications of process I, a routine method to measure bisretinoid compounds in vivo. Extra amounts of either ATR-dimer or A2E in mouse eyecups were released by processes II-IV versus process I. Efforts to clarify the effects of organic solvents on lipofuscin pigments are important because such studies can guide the handling of these fluorophores in related experiments.

Structures and biogenetic analysis of lipofuscin bis-retinoids.

Age-related macular degeneration (AMD) is still an incurable blinding eye disease because of complex pathogenic mechanisms and unusual diseased regions. With the use of chemical biology tools, great progress has been achieved in improving the understanding of AMD pathogenesis. The severity of AMD is, at least in part, linked to the non-degradable lipofuscin bis-retinoids in retinal pigment epithelial (RPE). This material is thought to result from the lifelong accumulation of lysosomal residual bodies containing the end products derived from the daily phagocytosis of rod outer segments by RPE cells. Here, we present previously recognized bis-retinoids with focus on structures and biosynthetic pathways. In addition to a brief discussion on the mutual conversion relationships of bis-retinoids, future perspectives and the medical relevance of such studies on these lipofuscin constituents are also highlighted.

Information extraction for tracking liver cancer patients' statuses: from mixture of clinical narrative report types.

OBJECTIVE: To provide an efficient way for tracking patients' condition over long periods of time and to facilitate the collection of clinical data from different types of narrative reports, it is critical to develop an efficient method for smoothly analyzing the clinical data accumulated in narrative reports. MATERIALS AND METHODS: To facilitate liver cancer clinical research, a method was developed for extracting clinical factors from various types of narrative clinical reports, including ultrasound reports, radiology reports, pathology reports, operation notes, admission notes, and discharge summaries. An information extraction (IE) module was developed for tracking disease progression in liver cancer patients over time, and a rule-based classifier was developed for answering whether patients met the clinical research eligibility criteria. The classifier provided the answers and direct/indirect evidence (evidence sentences) for the clinical questions. To evaluate the implemented IE module and the classifier, the gold-standard annotations and answers were developed manually, and the results of the implemented system were compared with the gold standard. RESULTS: The IE model achieved an F-score from 92.40% to 99.59%, and the classifier achieved accuracy from 96.15% to 100%. CONCLUSIONS: The application was successfully applied to the various types of narrative clinical reports. It might be applied to the key extraction for other types of cancer patients.

Preliminary studies on the chemical characterization and antioxidant properties of acidic polysaccharides from Sargassum fusiforme.

In order to investigate the antioxidant properties of the polysaccharides from the brown alga Sargassum fusiforme, the crude polysaccharides from S. fusiforme (SFPS) were extracted in hot water, and the lipid peroxidation inhibition assay exhibited that SFPS possessed a potential antioxidant activity. Hence, two purely polymeric fractions, SFPS-1 and SFPS-2 were isolated by the column of DEAE (2-diethylaminoethanol)-Sepharose Fast Flow, with their molecular weights of 51.4 and 30.3 kDa determined by high performance gel permeation chromatography (HPGPC). They were preliminarily characterized using chemical analysis in combination of infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and found to contain large amounts of uronic acids and beta-glycosidical linkages. The antioxidant activities of these two SFPS fractions were evaluated using superoxide and hydroxyl radical-scavenging assays. The results show that the antioxidant ability of SFPS-2 was higher than that of SFPS-1, probably correlating with the molecular weight and uronic acid content.