Melatonin pretreatment protects against focal cerebral ischemia in the rat

Melatonin (MT) possesses many properties of an ideal neuroprotectant. In this study, the neuroprotective effects of exogenous MT were tested in a middle cerebral artery occlusion (MCAO) stroke model. Adult male Sprague-Dawley rats (280 to 360 g) were anesthetized with sodium pentobarbital (60 mg/kg, I.P.) to undergo reversible right-sided endovascular MCAO for 3 hours. Arterial blood pressure, heart rate and cerebral blood flow (CBF) were monitored, and rectal temperature was kept between 36.5 and 37.5 ºC throughout anesthesia. One I.P. dose of MT (at 1.5, 5, or 15 mg/kg) or the vehicle was given 30 minutes before onset of ischemia. The rats were decapitated on day 3 of MCAO, and their brains were stained with 2% triphenyltetrazolium chloride for determination of infarction. Results were compared using 2-tailed student’s t test. When compared to the relative infarct volume of 31.8±3.3% (mean±SEM; 16 rats) in the control group, treatment with MT reduced the relative infarct volume in a dose-dependent manner (30.5±3.2% in the 1.5 mg/kg group [17 rats]; 15.9±2.2% in the 5 mg/kg group [16 rats], P < 0.05; 21.4±3.0% in the 15 mg/kg group [15 rats], P < 0.05). There was no significant difference in heart rate, arterial blood pressure and CBF among the groups. We concluded that a single dose of MT between 5 and 15 mg/kg protects against focal cerebral ischemia, when given 30 minutes before onset of ischemia. The above doses of MT do not produce significant hemodynamic effects nor alter the CBF during ischemia and reperfusion. Supported by the CRCG Research Grant 10202138 of the University of Hong Kongpublished_or_final_versio

In vivo neuroprotection of melatonin against focal cerebral ischaemia in the rat

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The enhancement of community integration in Hong Kong: Coping strategies of Chinese parents of children with autism spectrum disorders

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The enhancement of community integration in Hong Kong: Coping strategies of Chinese parents of children with autism spectrum disorders

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A Tale Of Two Societies: The Doing Of Qualitative Comparative Research In Hong Kong And Britain

This paper reports on some of the challenges and benefits of international collaboration in conducting comparative qualitative research, drawing on our experience of working together on a small exploratory study of two generations of women in Britain and Hong Kong. Cross-national collaborative research is now common in Europe, a product of European funding, but it is far rarer to find qualitative, cross cultural studies of societies that are geographically and culturally more distant from each other. Moreover, texts dealing with cross-cultural qualitative fieldwork are generally based on the premise of a researcher from one culture (usually from rich countries or the global north) working in ‘other’ cultures (Liamputtong 2010; Cleary 2013) and therefore focus on issues of cultural knowledge and sensitivity. Where collaboration is mentioned it is generally in terms of outsiders working with local communities or local researchers (Cleary 2013). Our study was not of this kind. We worked as an equal partnership between two principal investigators, one Hong Kong Chinese (H) and the other white British (J) and with the intention of comparing the lives of Hong Kong Chinese and white British women, the majority ethnicities in the two locations.published_or_final_versio

Development of a community-based network to promote smoking cessation among female smokers in Hong Kong

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Association of proinflammatory cytokines and chemotherapy-associated cognitive impairment in breast cancer patients: a multi-centered, prospective, cohort study.

BackgroundExisting evidence suggests that proinflammatory cytokines play an intermediary role in postchemotherapy cognitive impairment. This is one of the largest multicentered, cohort studies conducted in Singapore to evaluate the prevalence and proinflammatory biomarkers associated with cognitive impairment in breast cancer patients.Patients and methodsChemotherapy-receiving breast cancer patients (stages I-III) were recruited. Proinflammatory plasma cytokines concentrations [interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, granulocyte-macrophage colony-stimulating factor, interferon-γ and tumor necrosis factor-α] were evaluated at 3 time points (before chemotherapy, 6 and 12 weeks after chemotherapy initiation). The FACT-Cog (version 3) was utilized to evaluate patients' self-perceived cognitive disturbances and a computerized neuropsychological assessment (Headminder) was administered to evaluate patients' memory, attention, response speed and processing speed. Changes of cognition throughout chemotherapy treatment were compared against the baseline. Linear mixed-effects models were applied to test the relationships of clinical variables and cytokine concentrations on self-perceived cognitive disturbances and each objective cognitive domain.ResultsNinety-nine patients were included (age 50.5 ± 8.4 years; 81.8% Chinese; mean duration of education = 10.8 ± 3.3 years). Higher plasma IL-1β was associated with poorer response speed performance (estimate: -0.78; 95% confidence interval (CI) -1.34 to -0.03; P = 0.023), and a higher concentration of IL-4 was associated with better response speed performance (P = 0.022). Higher concentrations of IL-1β and IL-6 were associated with more severe self-perceived cognitive disturbances (P = 0.018 and 0.001, respectively). Patients with higher concentrations of IL-4 also reported less severe cognitive disturbances (P = 0.022).ConclusionsWhile elevated concentrations of IL-6 and IL-1β were observed in patients with poorer response speed performance and perceived cognitive disturbances, IL-4 may be protective against chemotherapy-associated cognitive impairment. This study is important because cytokines would potentially be mechanistic mediators of chemotherapy-associated cognitive changes

Fitness Ranking of Individual Mutants Drives Patterns of Epistatic Interactions in HIV-1

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