Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 193-221) Also available in print.

Chapter one of my thesis has been published in the May 2008 issue of the journal Evolution under the title “A TALE OF TWO CONTINENTS: BAKER’S RULE AND THE MAINTENANCE OF SELF-INCOMPATIBILITY IN LYCIUM (SOLANACEAE).” This chapter was co-authored by Dr. Jill S. Miller and Dr. Rachel Levin.

This diploma thesis deals with application of wolfberry (Lycium chinense) and maca (Lepidium meyenii) in food products. Both plants have high nutrition content and are studied for their health benefits to humans. In case of wolfberry it’s mainly immune-stimulating and antioxidant properties. Maca is known for increasing fertility and there’s also reported lowering of cholesterol and blood sugar. In theoretic part are summarized findings about chemical composition, science studies about effects of these plants, situation on the Czech trade and project of use. Aim of this thesis was to create practical demonstration of use and consumption both plants and to evaluate it by methods of sensory analysis. For this purpose three samples of wolfberry cereal bars and three samples of chocolate with maca powder were produced. These samples were sensory evaluated using ranking test, scale test and profile test. Higher amount of maca in chocolate had worse rating, while use of wolfberry was rated quite well. Therefore three wolfberry cereal bars were produced as the final product in cooperation with bakery and chocolate factory Fikar – bar with fruit filling glazed with chocolate, classical bar glazed and classical bar not glazed with chocolate, as a demonstration of possible industrial use.

published_or_final_version / abstract / Obstetrics and Gynaecology / Master / Master of Philosophy

published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Understanding the salt marsh ecosystem in the Guadalupe Estuary is needed because wetlands in this system support the endangered whooping crane (Grus americana). The marsh plant research and monitoring described herein were based in the salt marshes at Aransas National Wildlife Refuge (ANWR), which are utilized by the cranes each winter. Past research indicates that the Carolina wolfberry (Lycium carolinianum) contributes 21-52% of crane energy intake early in the wintering period (Chavez 1996). Beginning in Fall 2003, vegetation transects were sampled along an estuarine gradient at ANWR. Species diversity and composition was similar at the three sites, with all sites containing the same 6-7 common species. While Spartina alterniflora is only a minor part of this vegetation community, it dominates the few low inter-tidal, fringe areas present. Species composition exhibited little variability from Year 1 to Year 2 of the study. Densities and biomass of L. carolinianum were not significantly different between sites or years. L. carolinianum, while important to salt marsh ecology, accounts for only a small portion of the overall productivity. Based on correlation coefficients, L. carolinianum was found in association with some of the common species in the vegetation community, indicating that its growth and survival requirements are typical to the salt marshes at ANWR. Also beginning in Fall 2003, I repeatedly sampled L. carolinianum in permanent plots along the estuarine gradient. L. carolinianum exhibits strong temporal patterns. Leaf production peaked in early spring and again just prior to peak berry abundance. Flowering of L. carolinianum occurred in October and November. Peak berry abundance coincided with the cranes’ arrival in late October and early November. Berry production occurred in October, November, and December; berries were virtually non-existent in the marshes for the remainder of the year. Stepwise regression showed stem diameter alone was a good estimator of aboveground biomass of this species in ANWR marshes, accounting for 94% of the variability (p<0.001). Changes in aboveground biomass followed no distinct patterns in the year of monitoring, perhaps due to the woody stem of the plant. Spatial patterns in L. carolinianum were not explained by water quality parameters alone; it is suggested that soil properties may help to account for the spatial variability.

In order to understand the possible mechanisms in the glaucoma-related retinopathy, the role of the vasoconstrictor, endothelin-1 (ET-1), receptor for advanced glycation end-products (RAGE) as well as its ligand, Aβ in the degeneration of retinal ganglion cells (RGCs) were studied in experimental models. In addition, the relationship of ET-1, RAGE and Aβ for the RGC protective mechanism of Lycium Barbarum (LB) was also investigated. In the first part, ET-1 together with its receptors, ETA and ETB, were studied to understand their possible roles in chronic ocular hypertension (COH). The neuronal protective mechanism of LB was also determined by using a well established COH rat model. In normal rats, ET-1 and its receptors, ETA and ETB, were distributed in the retina, vasculature and optic nerve. Interestingly, ET-1 expression was up-regulated after COH. LB could decrease the expression of ET-1 and regulate its receptors (up-regulation of ETB and down-regulation of ETA in vasculature; up-regulation of ETA and down-regulation of ETB in RGCs) under the condition of COH. These data suggested that the RGC protective mechanism of LB might be related to its ability to regulate the biological effects of ET-1. To investigate the pathogenic effect of ET-1 in glaucoma, in the second part, we used transgenic mice with over-expression of ET-1 on endothelial cells (TET-1 mice). We found that beginning at 10-12 months, TET-1 mice showed a progressive retinal degeneration (loss of RGCs associated with neurons in the inner nuclear layer and outer nuclear layer of the retina) without elevation of the intraocular pressure (IOP). The data demonstrated that TET-1 mice may serve as a potential model to investigate the role of endothelial ET-1 in the pathogenesis of normal tension glaucoma and other degenerative retinopathy. To investigate whether LB plays a role on neuronal protection other than in COH, in the third part, we used an acute ocular hypertension (AOH)-induced ischemia mouse model. We found that LB could rescue RGCs under AOH insult, associating with blood vessel protection (decreasing the damage of blood-retinal-barriers and rescuing the survival of endothelial cells and pericytes) and inhibiting retinal gliosis. We also found the protective mechanism of LB was closely correlated with down-regulation of the expression of RAGE, ET-1, APP (amyloid precursor protein), AGE (advanced glycation end-product) as well as Aβ; therefore to reduce the damage effects of these RAGE-mediated reactions to the retinal neurons, blood vessels and glial cells involved in the ischemic insult. Taken together, the present study demonstrated that TET-1 mice may be a potential model for investigating the role of ET-1 in degenerative retinopathies, such as normal tension glaucoma. We also showed the neuronal protective mechanism of LB in vivo was associated with inhibiting the biological effect of ET-1 and down-regulating the damage signaling pathways mediated by the activation of RAGE and its ligands (AGE and Aβ). These results provided further understandings in the mechanism of the glaucoma-related retinopathy. In addition, LB could be a neuroprotective agent to the retina following both chronic and acute injuries. / published_or_final_version / Anatomy / Doctoral / Doctor of Philosophy

Ischemic stroke is a devastating cerebrovascular disease resulting in high mortality rate and distressing sequelae such as hemiplegia, ataxia and even visual impairment. Retinal ischemia refers to a common pathological feature shared by many blinding diseases including retinal vascular occlusions, diabetic retinopathy, glaucoma, and retinopathy of prematurity. Ischemia/reperfusion injury is implicated in both of these pathological conditions, which greatly impact on one’s daily life. The eventual consequence of the insult is irreversible neuronal cell death and functional deterioration. Apart from current symptomatic treatment for these diseases, researchers and clinicians are dedicated to look for ideal neuroprotectant to meet the clinical needs. Traditional Chinese medicine has been received accumulating attention in recent years, and Lycium barbarum is one of them. The polysaccharides (LBP) utilized in the present study are the rich extracts of the fruit of Lycium barbarum that has been shown to exert many biological effects. This study aims to evaluate its protective effects in cerebral and retinal ischemia, which has not yet been fully investigated. A well-established rodent model, middle cerebral artery occlusion, was utilized in the present study to mimic cerebral and retinal ischemia/reperfusion injury. In the study of cerebral ischemia, both pre-treatment and post-treatment of LBP were explored. Seven-day LBP pre-treatment revealed significant protection against neurological deficits and cerebral infarction. Besides, it attenuated cerebral edema and glial activation, as well as preserved blood-brain barrier integrity. Further study showed that these beneficial effects of LBP pre-treatment might act via anti-apoptosis, antioxidation and anti-inflammation. However, similar findings were not noted in LBP post-treatment experiments, possibly due to the timing of intervention. In the investigation of retinal ischemia, the observation time was prolonged to 7 days after the insult. Electroretinogram was used to evaluate the functional alternation of retinal neurons. Sustained retinal dysfunction was induced by two-hour ischemia. LBP pre-treatment with continuous daily supplementation effectively alleviated visual dysfunction and protected the retina from morphological impairment including neuronal death, glial activation and blood-retinal barrier disruption. Similarly, these protective effects might be associated with the involvement of attenuation of apoptosis and oxidative stress. In conclusion, LBP pre-treatment with continuous daily supplementation protected the brain and retina, both functionally and morphologically, from ischemia/reperfusion injury. This dosing regimen hold great promise in serving as a prophylactic neuroprotectant in patients at high risk for ischemic stroke, as well as preserving normal visual function and reducing irreversible neuronal death in ischemic retinopathies. Further studies on the active ingredients and underlying mechanisms would be informative for better application of LBP in clinical situation. / published_or_final_version / Ophthalmology / Doctoral / Doctor of Philosophy