published_or_final_version / Medicine / Doctoral / Doctor of Philosophy

published_or_final_version / Public Health / Master / Master of Public Health

While obstructive sleep apnea among children with Down syndrome is very common, the pre-existing risk factors and its impact to neurodevelopment are not well known. The aims and objectives of this systematic review are to determine the prevalence of OSA among DS children and to identify the associated risk factors. 6 articles that met the inclusion criteria were retrieved after using PubMed and Google Scholar in literature searching. The prevalence of OSA has great variation among different countries but are relatively high, ranging from 57% to 79%. OSA was significant associated with obesity, age and tonsil size. It is also known to associate with behavioral problem in DS children and delay their neurodevelopment. Therefore, early treatment followed by appropriate modification in lifestyle and diet is crucial in managing OSA. / published_or_final_version / Public Health / Master / Master of Public Health

Objective: Obesity has become one of the major global public epidemic problems while the knowledge of childhood obesity is a bit limited within Chinese study. This review examined the association between sleep duration and childhood overweight and obesity in China. Methods: This systematic review was conducted by searching online electronic resources of papers from PubMed and Chinese database CNKI published up to 2013. The keywords of “sleep” OR “risk factors” AND “obesity OR overweight” AND “child OR adolescent” AND “China OR Hong Kong OR Taiwan” were used for searching and identifying. The search filter to restrict the study design as the observational study written in English or Chinese in these databases was used. Results: Four case-control studies, and eight cross-sectional studies were included in the systematic review. Despite of different method in assessing sleep duration, all included studies suggested that sleep duration is consistently and negatively related with childhood obesity, mainly assessed using Body Mass Index (BMI) in China. Conclusion: Most included articles reported the association between short sleep duration and childhood obesity/overweight. However, given the cross-section nature of the data, the causal relation between sleep duration and obesity remains unclear. Whether sleep duration may be the factor to be considered in childhood obesity prevention strategies remains to be confirmed possibly by studies with longitudinal design or randomized control trials. / published_or_final_version / Medicine / Master / Master of Public Health

Background Insomnia is a common and increasing illness among general population all over the world. With insomnia, patients would more likely to have physical, social dysfunction and mood disorders, and even have increased risk of accidents. Therefore, identifying the harm of insomnia and improving the quality of life of patients are very important. Objectives The objective of this systematic review is to evaluate quality of life in patients affected with insomnia. Particularly focuses on the following two question: 1) How insomnia impact quality of life in patients with insomnia. 2) What factors affect quality of life among people with insomnia, such as demographic factors, physical and psychological factors. Methods Systematic reviewing the articles from 1990 to 2013 in PubMed and Medline, which evaluated the quality of life in patients affected with insomnia, using the keywords “insomnia” AND “quality of life”. Results and Discussion There were 9 articles have been included in this review. The year were ranged from 1998 to 2012,8 out of 9 papers had the average age ranged from 42-57 year old. Insomnia significantly related to all of the eight domains and PCS,MCS of QOL negatively, and both of the severity of insomnia and the number of sleep problems have negative impact on QOL. Moreover, regarding the factors which affect QOL of patients, older, female, not married, smoking, drinking, psychiatric disorders and without treatment were associated with lower QOL. Furthermore, regarding the future directions, in Hong Kong the application of the results in this review is appropriate but still need more studies which evaluating the associated factors of insomniacs’ QOL with validated Chinese version QOL measures. Conclusion There was a negative relationship between insomnia and quality of life, and the severity of insomnia and the number of sleep problems had negative impact on quality of life. Particularly, older, female, single statuse, smoking, drinking, psychiatric disorders had negative influence on patients’s QOL. Regarding the control strategies, using appropriate medical treatment under physician guidance, consultation of mental disorders, increasing the public awareness of the harm of insomnia play a pivotal role in reduce the impairment of insomnia. / published_or_final_version / Public Health / Master / Master of Public Health

Major depressive disorder (MDD) is a debilitating disorder affecting hundreds of millions of people worldwide. The etiology of the disease is unknown, and how antidepressant medications reverse depression is unclear. However, imaging and postmortem studies of MDD patients show abnormalities in several limbic areas of the brain, including the prefrontal cortex. The involvement of the ventromedial prefrontal cortex (vmPFC) in depression has been particularly intriguing, for this region demonstrates reduced metabolic activity in remission, and this reduction is unique to treatment responders. In addition, deep brain stimulation targeting the subgenual cingulate cortex in the vmPFC has been shown to be effective in treating 'treatment-resistant' patients. Furthermore, neuroanatomical studies have shown that this region projects to many downstream limbic areas implicated to play roles in MDD. I therefore hypothesized that 1) the vmPFC may be an important target of antidepressant drugs, and that 2) this region may play a role in the generation of depression-associated behaviors. To test the first hypothesis, I administered desipramine (DMI), a tricyclic antidepressant, to rats. I found that the rat vmPFC was significantly activated by DMI, whereas the dorsomedial PFC (dmPFC) was not. I also found that the drug increases neuronal activity in the nucleus accumbens, but this activation was dependent on the integrity of the vmPFC. To test the second hypothesis, I induced neuronal lesions in the rat dmPFC or vmPFC and subjected the animals to behavioral tests. I found that while lesions in both areas led to increased REM sleep, only vmPFC-lesioned animals had reduced REM latency, increased sleep fragmentation and increased forced swim test immobility. Together, these results demonstrate that the vmPFC may be an important region for both antidepressant action and the generation of depression-like behaviors.

Not available / text

published_or_final_version / Dentistry / Master / Master of Orthodontics

Brazilian tegus (Tupinambis merianae) were instrumented with telemetry encoder implants that measured and broadcast heart rate (HR), breathing rate (fR), and deep body temperature (Tb) and were then allowed to freely roam in outdoor enclosures mimicking their natural environment for a full year (2004) in order to monitor the circadian and circannual patterns in behaviour and cardio-respiratory physiology. The year was divided up into 5 seasons based upon the physiology and behaviour of the tegus: early activity season (Sept.-Nov.), late activity season (Dec.-Feb.), entrance into hibernation (March-April), hibernation (May-July), and arousal from hibernation (August). The activity seasons were characterized by warm weather with frequent rainfall which slowly decreased in temperature and precipitation as tegus started entering hibernation so that the end of the dormant season was marked by dry, cold weather. Tegus in the early activity season demonstrated high activity associated with breeding demands, displayed elevated HR and fR, and were able to maintain a large temperature differential (4-7°C) between deep body temperature (Tb) and their respective burrow (Tburrow) during sleep. As the season progressed into late activity season, average Tb remained constant but average HR and fR progressively declined indicating nightly torpor. Periods of inactivity during the active seasons were rare and associated with inclement weather. Tegus entered hibernation through bouts of inactivity that progressively increased in frequency and duration. During this time, Tb was regulated but declined at different rates in regards to daytime and nighttime values. Heart rate through the entrance into hibernation and hibernation periods frequently demonstrated arrhythmias that increased in duration but decreased with frequency as hibernation progressed. Through hibernation, Tb continued to decline for the first month but HR and fR were constant, demonstrating a temperature independent suppression of metabolism. Through the hibernation season tegus sporadically aroused and emerged from their burrows to warm up and after a short basking period would return to the burrows and swiftly resume hibernation. While hibernating, heart rate was characteristically regular but breathing was sporadic orepisodic. Arousals became more frequent towards the end of hibernation so that when they entered arousal from hibernation season most tegus were emerging daily. At this time daily maximum deep body temperature (Tbmax) swiftly returned to active season values but nighttime daily minimum deep body temperature (Tbmirt) values only showed a gradual increase through August, indicating different body temperature set points (Tbset) for active and sleep states. Changes in heart rate and breathing rate during the year showed greatest correlation with changes in photoperiod, although throughout hibernation HR and fR also showed tight correlation with Tb.

Menopausal symptoms, including sleep problems, occur as a result of reduced production of ovarian hormones in middle-aged women, and are often treated with replacement of these hormones. However, the efficacy of hormone replacement for improving sleep is controversial. We assessed sleep/wake patterns during baseline and recovery following 6 h of sleep deprivation in ovariectomized middle-aged rats treated with oil, estradiol, or estradiol and progesterone. We found that, at baseline, hormone administration reduced rapid eye movement (REM) sleep initiation and non-REM sleep amount, promoting wakefulness, particularly during the dark (active) phase, but that, during recovery following sleep deprivation, hormonal treatment reduced sleep intensity initially and lengthened REM sleep recovery. These results indicate that in middle-aged female rats ovarian hormones modulate baseline and recovery sleep differently, possibly by modulating circadian and homeostatic regulation of sleep in an age-dependent manner.