Quality of life (QoL) in southern Chinese with systemic lupus erythematosus (SLE)

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Neuroprotective effects of Lycium barbarum polysaccharides against rat hippocampal apoptosis induced by chronic intermittent hypoxia

Poster presentationWe have shown neuronal apoptosis in the hippocampus of rats exposed to chronic intermittent hypoxia mimicking severe conditions of obstructive sleep apnea (OSA) syndrome in patients [1]. Lycium barbarum polysaccharides (LBP), active biological ingredients of traditional Chinese herbal medicine Goji, have been shown to possess cytoprotective properties [2]. The aim of this study was to examine the protective effects of LBP against neuronal apoptosis in the hippocampus in a severe OSA rodent model. We hypothesized that oral administration of LBP ameliorates neuronal apoptosis in the rat hippocampus induced by chronic intermittent hypoxia. Adult SD rats were randomly divided into 4 experimental groups, namely: (i) normoxic control (Nx); (ii) Nx treated with LBP; hypoxic groups treated with either (iii) LBP or (iv) vehicle. The hypoxic groups were kept in a normobaric chamber with inspired oxygen alternating from 21 to 5 ± 0.5% oxygen per minute for 8 hr/day for 7 days, whereas Nx groups was maintained in room air for 7 days. LBP (1mg/kg) were orally fed to the rats 2 hours prior the daily hypoxic treatment. Rats were sacrificed and the hippocampus was harvested for measurements of oxidative marker, malondialdehyde (MDA), apoptotic cell death using TUNEL assay, protein expression levels of antioxidant enzymes, and inflammatory cytokines by Western blot. There were significantly more TUNEL positive –labeling cells in the CA regions and dentate gyrus of the hippocampus in the vehicle-treated hypoxic group than those of the Nx control and LBP-treated groups. In addition, levels of MDA and the protein expressions of cleaved caspase 3 and inflammatory cytokines were increased in the vehicle-treated hypoxic group when compared to the Nx groups and were lowered by the LBP treatment. Intriguingly, there were significantly more PCNA-labeling cells in the dentate gyrus of the hippocampus in the LBP-treated hypoxic groups than those of the other groups. Also, the protein expression of cyclin D1 was increased in the hypoxic groups when compared to the Nx groups. In conclusion, oral administration of LBP significantly ameliorates oxidative stress, inflammation and neuronal apoptosis with enhanced proliferative activities in the hippocampus of rats exposed to chronic intermittent hypoxia. Thus, LBP may be proposed as a health supplement to mitigate neurological deficits in OSA patients, for which awaits future studies to delineate the neuroprotective mechanism of LBP. [Studies supported by research grants (HKU 7510/06M, HKU 766110M) from RGC and funding (201007176007, SFPBR 200911159072) from HKU] [1] Hung, M.W., et al. (2008) J Pineal Res 44: 214-221. [2] Chang, R.C., et al. (2008). Cell Mol Neurobiol 28: 643-652.published_or_final_versio

Neuroprotective Mechanism of Lycium barbarum Polysaccharides against Hippocampal-Dependent Spatial Memory Deficits in a Rat Model of Obstructive Sleep Apnea

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A robust computational algorithm for inverse photomask synthesis in optical projection lithography

Inverse lithography technology formulates the photomask synthesis as an inverse mathematical problem. To solve this, we propose a variational functional and develop a robust computational algorithm, where the proposed functional takes into account the process variations and incorporates several regularization terms that can control the mask complexity. We establish the existence of the minimizer of the functional, and in order to optimize it effectively, we adopt an alternating minimization procedure with Chambolle's fast duality projection algorithm. Experimental results show that our proposed algorithm is effective in synthesizing high quality photomasks as compared with existing methods.published_or_final_versio

Monoamine oxidase A upregulated by chronic intermittent hypoxia activates indoleamine 2,3-dioxygenase and neurodegeneration

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M30 Antagonizes Indoleamine 2,3-Dioxygenase Activation and Neurodegeneration Induced by Corticosterone in the Hippocampus

Monoamine oxidases (MAO), downstream targets of glucocorticoid, maintain the turnover and homeostasis of monoamine neurotransmitters; yet, its pathophysiological role in monoamine deficiency, oxidative stress and neuroinflammation remains controversial. Protective effects of M30, a brain selective MAO inhibitor with iron-chelating antioxidant properties, have been shown in models of neurodegenerative diseases. This study aims to examine the neuroprotective mechanism of M30 against depressive-like behavior induced by corticosterone (CORT). Sprague-Dawley rats were given CORT subcutaneous injections with or without concomitant M30 administration for two weeks. CORT-treated rats exhibited depressive-like behavior with significant elevated levels of MAO activities, serotonin turnover, oxidative stress, neuroinflammation and apoptosis in the hippocampus with significant losses of synaptic proteins when compared to the control. The expression and activity of cytokine-responsive indoleamine 2,3-dioxygenase (IDO-1), a catabolic enzyme of serotonin and tryptophan, was significantly increased in the CORT-treated group with lowered levels of serotonin. Besides, CORT markedly reduced dendritic length and spine density. Remarkably, M30 administration neutralized the aberrant changes in the hippocampus and prevented the induction of depressive-like behavior induced by CORT. Our results suggest that M30 is neuroprotective against CORT-induced depression targeting elevated MAO activities that cause oxidative stress and neuroinflammation, resulting in IDO-1 activation, serotonin deficiency and neurodegeneration.published_or_final_versio

Diffuse panbronchiolitis: the Hong Kong experience

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The clinical profile and respiratory ciliary assessment in Kartageners syndrome

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The relationship between sputum microbial load and leucocyte count in stable bronchiectasis

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Characterization of the chronobiological signals based on the continuous wavelet transform

Chronobiology, which studies periodic patterns or rhythms of the living beings, often needs to characterize the observed chronobiological time series (CTS) and to study the stability and adaptability of the periodic patterns in different environmental conditions. Fourier transform (FT) based methods and complex demodulation (CD) approach have been widely used in such study. However, the former lacks temporal resolution and the later needs to extract the temporal behaviors of individual frequencies. In this paper, we proposed a new approach to characterize the CTS based on the continuous wavelet transform (CWT). It allows us to investigate the time-frequency dynamics of different rhythmic-band activities in the CTS simultaneously. Two application results have been presented to illustrate the proposed method.published_or_final_versio