Pharmacogenomics and the Yin/Yang actions of ginseng: anti-tumor, angiomodulating and steroid-like activities of ginsenosides.

In Chinese medicine, ginseng (Panax ginseng C.A. Meyer) has long been used as a general tonic or an adaptogen to promote longevity and enhance bodily functions. It has also been claimed to be effective in combating stress, fatigue, oxidants, cancer and diabetes mellitus. Most of the pharmacological actions of ginseng are attributed to one type of its constituents, namely the ginsenosides. In this review, we focus on the recent advances in the study of ginsenosides on angiogenesis which is related to many pathological conditions including tumor progression and cardiovascular dysfunctions. Angiogenesis in the human body is regulated by two sets of counteracting factors, angiogenic stimulators and inhibitors. The 'Yin and Yang' action of ginseng on angiomodulation was paralleled by the experimental data showing angiogenesis was indeed related to the compositional ratio between ginsenosides Rg1 and Rb1. Rg1 was later found to stimulate angiogenesis through augmenting the production of nitric oxide (NO) and vascular endothelial growth factor (VEGF). Mechanistic studies revealed that such responses were mediated through the PI3K-->Akt pathway. By means of DNA microarray, a group of genes related to cell adhesion, migration and cytoskeleton were found to be up-regulated in endothelial cells. These gene products may interact in a hierarchical cascade pattern to modulate cell architectural dynamics which is concomitant to the observed phenomena in angiogenesis. By contrast, the anti-tumor and anti-angiogenic effects of ginsenosides (e.g. Rg3 and Rh2) have been demonstrated in various models of tumor and endothelial cells, indicating that ginsenosides with opposing activities are present in ginseng. Ginsenosides and Panax ginseng extracts have been shown to exert protective effects on vascular dysfunctions, such as hypertension, atherosclerotic disorders and ischemic injury. Recent work has demonstrates the target molecules of ginsenosides to be a group of nuclear steroid hormone receptors. These lines of evidence support that the interaction between ginsenosides and various nuclear steroid hormone receptors may explain the diverse pharmacological activities of ginseng. These findings may also lead to development of more efficacious ginseng-derived therapeutics for angiogenesis-related diseases

Está insatisfeito com o seu chefe? Será devido a ele ou a si? O efeito que o locus de controlo tem na relação entre liderança e satisfação

Dissertação de Mestrado apresentada no ISPA - Instituto Universitário para a obtenção de grau de Mestre na especialidade de Psicologia Social e das Organizações.A presente investigação teve como objetivo estudar a relação que existe entre as variáveis Liderança, Satisfação com o Líder e Locus de Controlo, no âmbito organizacional. Sendo assim, o principal objetivo da investigação é estudar se a relação entre Liderança e Satisfação com o Supervisor é positiva ou negativa, e se o Locus de Controlo tem um efeito moderador nessa mesma relação. A amostra desta dissertação é composta por 149 trabalhadores (dos quais 68% são do género feminino) recrutados através do método snowball, e que têm supervisão direta. A avaliação da Liderança Transformacional e Transacional foi feita através do Questionário Multifatorial de Liderança (Salanova, Lorente, Chambel, & Martínez, 2011); a Satisfação com o Supervisor foi avaliada com recurso a parte do Questionário de Satisfação Laboral S20/23, (Pocinho e Garcia, 2008); e o Locus de Controlo foi medido através da escala MASLOC (Multidimensional Academic-Specific Locus of Control) (Barros, 1992). Os resultados indicam que existe uma relação positiva entre os dois estilos de Liderança e a Satisfação com o Supervisor. No entanto, o efeito de moderação do Locus de Controlo entre a Liderança e a Satisfação com o Supervisor não se verificou. No fim foram discutidas as implicações e limitações consideradas no presente estudo e foram feitas sugestões para estudos futuros.This research aimed to examine the relationship between Leadership, Satisfaction with Leadership, and Locus of Control in organizations. Specifically, this research tested if the relationship between leadership style and employees satisfaction with leadership is moderated by employees’ locus of control. Participants were 149 employees (68% of which were female), engaged in the current research through a snowball participant’s recruitment procedure. All participants had a direct supervisor. Transformational and transactional Leadership styles were measured using the Multifactorial Leadership Questionnaire (Salanova, Lorente, Chambel, & Martínez, 2011); Satisfaction with supervisor was assessed using part of the Satisfaction with Work Questionnaire (Pocinho & Garcia, 2008); and Locus of Control was measured using the MASLOC (Multidimensional Academic-Specific Locus of Control), (Barros, 1992). The research findings suggest that there is a positive relationship between supervisor’s Leadership style, and employees’ satisfaction with leadership. However, locus of control did not have any effect on this relationship. The study’s limitations and implications were also debated in the end of the dissertation

Developing a primary 4-6 initiation programme for newly arrived non-Chinese speaking children in Hong Kong

published_or_final_versionEducationMasterMaster of Educatio

Zebrafish as an In Vivo Model to Assess Epigenetic Effects of Ionizing Radiation

Exposure to ionizing radiations (IRs) is ubiquitous in our environment and can be categorized into “targeted” effects and “non-targeted” effects. In addition to inducing deoxyribonucleic acid (DNA) damage, IR exposure leads to epigenetic alterations that do not alter DNA sequence. Using an appropriate model to study the biological effects of radiation is crucial to better understand IR responses as well as to develop new strategies to alleviate exposure to IR. Zebrafish, Danio rerio, is a scientific model organism that has yielded scientific advances in several fields and recent studies show the usefulness of this vertebrate model in radiation biology. This review briefly describes both “targeted” and “non-targeted” effects, describes the findings in radiation biology using zebrafish as a model and highlights the potential of zebrafish to assess the epigenetic effects of IR, including DNA methylation, histone modifications and miRNA expression. Other in vivo models are included to compare observations made with zebrafish, or to illustrate the feasibility of in vivo models when the use of zebrafish was unavailable. Finally, tools to study epigenetic modifications in zebrafish, including changes in genome-wide DNA methylation, histone modifications and miRNA expression, are also described in this review

Effect of Photon Hormesis on Dose Responses to Alpha Particles in Zebrafish Embryos

Photon hormesis refers to the phenomenon where the biological effect of ionizing radiation with a high linear energy transfer (LET) value is diminished by photons with a low LET value. The present paper studied the effect of photon hormesis from X-rays on dose responses to alpha particles using embryos of the zebrafish (Danio rerio) as the in vivo vertebrate model. The toxicity of these ionizing radiations in the zebrafish embryos was assessed using the apoptotic counts at 20, 24, or 30 h post fertilization (hpf) revealed through acridine orange (AO) staining. For alpha-particle doses ≥ 4.4 mGy, the additional X-ray dose of 10 mGy significantly reduced the number of apoptotic cells at 24 hpf, which proved the presence of photon hormesis. Smaller alpha-particle doses might not have inflicted sufficient aggregate damages to trigger photon hormesis. The time gap T between the X-ray (10 mGy) and alpha-particle (4.4 mGy) exposures was also studied. Photon hormesis was present when T ≤ 30 min, but was absent when T = 60 min, at which time repair of damage induced by alpha particles would have completed to prevent their interactions with those induced by X-rays. Finally, the drop in the apoptotic counts at 24 hpf due to photon hormesis was explained by bringing the apoptotic events earlier to 20 hpf, which strongly supported the removal of aberrant cells through apoptosis as an underlying mechanism for photon hormesis