Long-term Levodopa Treatment Accelerates the Circadian Rhythm Dysfunction in a 6-hydroxydopamine Rat Model of Parkinson's Disease / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Parkinson's disease (PD) patients with long-term levodopa (L-DOPA) treatment are suffering from severe circadian dysfunction. However, it is hard to distinguish that the circadian disturbance in patients is due to the disease progression itself, or is affected by L-DOPA replacement therapy. This study was to investigate the role of L-DOPA on the circadian dysfunction in a rat model of PD.</p><p><b>METHODS</b>The rat model of PD was constructed by a bilateral striatal injection with 6-hydroxydopamine (6-OHDA), followed by administration of saline or 25 mg/kg L-DOPA for 21 consecutive days. Rotarod test, footprint test, and open-field test were carried out to evaluate the motor function. Striatum, suprachiasmatic nucleus (SCN), liver, and plasma were collected at 6:00, 12:00, 18:00, and 24:00. Quantitative real-time polymerase chain reaction was used to examine the expression of clock genes. Enzyme-linked immunosorbent assay was used to determine the secretion level of cortisol and melatonin. High-performance liquid chromatography was used to measure the neurotransmitters. Analysis of variance was used for data analysis.</p><p><b>RESULTS</b>L-DOPA alleviated the motor deficits induced by 6-OHDA lesions in the footprint and open-field test ( P < 0.01, P < 0.001, respectively). After L-DOPA treatment, Bmal1 decreased in the SCN compared with 6-OHDA group at 12:00 ( P < 0.01) and 24:00 ( P < 0.001). In the striatum, the expression of Bmal1, Rorα was lower than that in the 6-OHDA group at 18:00 (P < 0.05) and L-DOPA seemed to delay the peak of Per2 to 24:00. In liver, L-DOPA did not affect the rhythmicity and expression of these clock genes (P > 0.05). In addition, the cortisol secretion was increased (P > 0.05), but melatonin was further inhibited after L-DOPA treatment at 6:00 (P < 0.01).</p><p><b>CONCLUSIONS</b>In the circadian system of advanced PD rat models, circadian dysfunction is not only contributed by the degeneration of the disease itself but also long-term L-DOPA therapy may further aggravate it.</p>

Effects of temperature and hydraulic residence time (HRT) on treatment of dilute wastewater in a carrier anaerobic baffled reactor / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To examine the effect of hydraulic residence time (HRT) on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor (CABR), and hence to gain a deeper insight into microbial responses to hydraulic shocks on the base of the relationships among macroscopic performance, catabolic intermediate, and microcosmic alternation.</p><p><b>METHODS</b>COD, VFAs, and microbial activity were detected with constant feed strength (300 mg/L) at different HRTs (9-18 h) and temperatures (10 degrees C-28 degrees C) in a CABR.</p><p><b>RESULTS</b>The removal efficiencies declined with the decreases of HRTs and temperatures. However, the COD removal load was still higher at short HRT than at long HRT. Devastating reactor performance happened at temperature of 10 degrees C and at HRT of 9 h. HRTs had effect on the VFAs in the reactor slightly both at high and low temperatures, but the reasons differed from each other. Microbial activity was sensitive to indicate changes of environmental and operational parameters in the reactor.</p><p><b>CONCLUSION</b>The CABR offers to certain extent an application to treat dilute wastewater under a hydraulic-shock at temperatures from 10 degrees C to 28 degrees C.</p>