Induction of apoptosis by the ginsenoside Rh2 by internalization of lipid rafts and caveolae and inactivation of Akt

Background and purpose:

Lipid rafts and caveolae are membrane microdomains with important roles in cell survival signalling involving the Akt pathway. Cholesterol is important for the structure and function of these microdomains. The ginsenoside Rh2 exhibits anti-tumour activity. Because Rh2 is structurally similar to cholesterol, we investigated the possibility that Rh2 exerted its anti-tumour effect by modulating rafts and caveolae.

Experimental approach:

A431 cells (human epidermoid carcinoma cell line) were treated with Rh2 and the effects on cell apoptosis, raft localization and Akt activation measured. We also examined the effects of over-expression of Akt and active-Akt on Rh2-induced cell death.

Key results:

Rh2 induced apoptosis concentration- and time-dependently. Rh2 reduced the levels of rafts and caveolae in the plasma membrane and increased their internalization. Furthermore, Akt activity was decreased and consequently, Akt-dependent phosphorylation of Bad, a pro-survival protein, was decreased whereas the pro-apoptotic proteins, Bim and Bax, were increased upon Rh2 treatment. Unlike microdomain internalization induce by cholesterol depletion, Rh2-mediated internalization of rafts and caveolae was not reversed by cholesterol addition. Also, cholesterol addition did not restore Akt activation or rescue cells from Rh2-induced cell death. Rh2-induced cell death was attenuated in MDA-MB-231 cells over-expressing either wild-type or dominant-active Akt.

Conclusions and implications:

Rh2 induced internalization of rafts and caveolae, leading to Akt inactivation, and ultimately apoptosis. Because elevated levels of membrane rafts and caveolae, and Akt activation have been correlated with cancer development, internalization of these microdomains by Rh2 could potentially be used as an anti-cancer therapy.     

In-Vitro Assessment of the Acaricidal Properties of Artemisia annua and Zataria multiflora Essential Oils to Control Cattle Ticks

Background

The aim of this study was to investigate the ‘acaricidal effect’ of Zataria multiflora and Artemisia annua essential oils on Rhipicephalus (Boophilus) annulatus.

Methods

This study was carried out in 2009 in the Laboratory of Parasitology of the Faculty of Veterinary Medicine of Shahrekord University, west central Iran. Six dilutions (5, 10, 20, 40, 60 and 80 µL/cm³) of both essential oils were used against engorged female R. (Boophilus) annulatus ticks using an in vitro immersion method. The mortality rates for each treatment were recorded 6, 15 and 24 hours post inoculation (hpi). Mortality rate was analyzed using Repeated Measures Analysis of Variance, and comparison of means was carried out using General Linear Models Procedure.

Results

The mortality rate caused by different dilutions of Z. multiflora essential oil ranged from 26.6% (using 10 µL/cm³) to 100% (using 40 µL/cm³) and for A. annua essential oil it was 33.2 to 100% (using 20 and 80 µL/cm³, respectively) by the end of the experiment (36 hpi). No mortality was recorded for the non-treated control group or for dilutions less than 5 and 10 µL/cm³ using Zataria and Artemisia essential oils, respectively. For Z. multiflora mortality peaked at 15 hpi for all concentrations other than 20 µL/cm³ and took 24 h to achieve its maximum effect while for A. annua the two highest concentrations needed 24 hpi to reach their full effect. In addition, essential oils applied at more than 20 and 60 µL/cm³ caused 100% egg-laying failure in engorged female ticks by Zataria and Artemisia, respectively while no failure was observed for the non-treated control group. The mortality rate in both botanical acaricides was dose-dependent.

Conclusion

Both these medicinal plants have high potential acaricidal effects on the engorged stage of R. (Boophilus) annulatus in vitro.     

A comparison of Malone appendicostomy and cecostomy for antegrade access as adjuncts to a bowel management program for patients with functional constipation or fecal incontinence

Background

Appendicostomy and cecostomy are two approaches for antegrade enema access for children with severe constipation or fecal incontinence as adjuncts to a mechanical bowel management program. Each technique is associated with a unique set of complications. The purpose of our study was to report the rates of various complications associated with antegrade enema access techniques to help guide which option a clinician offers to their patients.

Peripheral blood CD4+CD8+ lymphocytes in cynomolgus monkeys are of resting memory T lineage

In this study, we analyzed peripheral blood CD4+CD8+ double-positive (DP) lymphocytes in adult cynomolgus monkeys (Macaca fascicularis). Forty of 55 monkeys had > 5% of the peripheral blood DP subpopulation (9.3 +/- 5.9%; mean +/- SD) in peripheral blood lymphocytes (PBL) in contrast to a low percentage of peripheral blood DP cells in humans and mice. In a cross-sectional study, the peripheral blood DP cells were found to increase in proportion with age. To clarify whether peripheral blood DP lymphocytes were immature precursors released from thymus without prior differentiation, the expressions of CD8 chains and CD1b on peripheral blood DP lymphocytes were compared with those on thymocytes. The peripheral blood DP lymphocytes were CD8 alpha + beta- and CD1b-, while thymic DP lymphocytes were CD8 alpha + beta + and CD1b +, suggesting that the peripheral blood DP cells are extrathymic T lymphocytes. Furthermore, the peripheral blood DP lymphocytes exhibited a resting memory T cell phenotype with CD2hiCD3+CD28-CD29hiCD49dhiCD69- CD80lo. Taken together, adult cynomolgus monkeys possess a unique peripheral blood DP T cell subpopulation which expresses a resting memory T cell phenotype. In addition, similar phenotypic properties of DP lymphocytes were distributed in the spleen and lymph nodes, although the proportion was less in the spleen and much less in lymph nodes than in PBL.      

Incidence of diabetic retinopathy in a Hong Kong Chinese population

Background: The aim was to examine the progression and regression of diabetic retinopathy within a four‐year period in a Chinese population with type 2 diabetes mellitus in a community optometry clinic in Hong Kong. Methods: During the period May 2005 to November 2009, 5,160 patients with type 2 diabetes mellitus who had attended at least two diabetic retinopathy screening sessions at a community optometry clinic were included as subjects in this study. All had retinal photographs taken of both eyes, which were of sufficiently good quality for grading. For the purpose of this study, diabetic retinopathy grading was based on the results of the worst eye. The main outcomes were the within four‐year incidence of diabetic retinopathy and the incidence of progression and regression of diabetic retinopathy. Results: Of the 5,160 subjects in this study, 3,647 had no diabetic retinopathy, while 1,513 had diabetic retinopathy at the baseline visit. Of those 3,647 subjects with no diabetic retinopathy, the within four‐year cumulative incidence of any diabetic retinopathy, mild or moderate non‐proliferative diabetic retinopathy and sight‐threatening diabetic retinopathy was 15.16 per cent, 14.45 per cent, 0.69 per cent and 0.03 per cent, respectively. Of those 1,513 subjects with diabetic retinopathy at baseline, the within four‐year progression incidence of diabetic retinopathy was 6.61 per cent and the regression incidence of diabetic retinopathy was 45.54 per cent. Conclusion: The high regression incidence of diabetic retinopathy suggests that it might not be necessary for all patients with diabetes to be screened annually. Other methods to determine the screening frequency for an individual patient should be explored.     

Comparison between elderly inpatient fallers with and without dementia

INTRODUCTION

This study aimed to examine the various factors associated with inpatient falls among patients with and without dementia in a hospital setting.

METHODS

This was a retrospective one-year study using data collected from Singapore General Hospital''s electronic reporting system for inpatient falls.

RESULTS

In the study period, 298 patients aged ≥ 65 years fell during their hospital stay. The majority of the patients (n = 248) did not have dementia. In our study, fallers with dementia were more likely to use ambulatory aids, be visually impaired and have urinary incontinence. More patients with dementia than those without had a history of previous falls, and were placed on fall precaution with restricted freedom of movement, which at times, included restraints. However, the difference between patients who were put on restraints and those who were allowed to move freely was not statistically significant. The majority of falls in both groups occurred at the bedside. We found that fallers without dementia were more likely to fall during the morning shift, whereas fallers with dementia were more likely to fall during the night shift. Fallers with dementia were more likely to be confused at the time of the fall.

CONCLUSION

In our study, we found that fallers with dementia were more likely to have visual impairment, have urinary incontinence, use walking aids, and to be confused and physically restrained at the time of the fall. The fallers without dementia in our study may have undiagnosed dementia.