Depression and low bone mineral density: a meta-analysis of epidemiologic studies

SUMMARY

The association between depression and loss of bone mineral density (BMD) has been reported inconsistently. This meta-analysis, which pooled results from 14 qualifying individual studies, found that depression was associated with a significantly decreased BMD, with a substantially greater BMD decrease in depressed women and in cases of clinical depression.

INTRODUCTION

The reported association between depression and loss of BMD has been controversial. This meta-analysis was conducted to determine whether depression and BMD are associated and to identify the variation in some subgroups.

METHODS

English-language articles published before October 2008 were used as the data source. A total of six case-controlled and eight cross-sectional studies met prestated inclusion criteria (N = 10,523). Information on study design, participant characteristics, measurements of BMD and depression, and control for potential confounders was abstracted independently by two investigators using a standardized protocol.

RESULTS

Overall, depression was associated with a significant decrease in mean BMD of spine (-0.053 g/cm(2) [95% confidence interval {CI} -0.087 to -0.018 g/cm(2)]) and hip (-0.052 g/cm(2) [95% CI -0.083 to -0.022 g/cm(2)]). A substantially greater BMD decrease was observed in depressed women (-0.076 g/cm(2) in spine; -0.059 g/cm(2) in hip) and in cases of clinical depression (-0.074 g/cm(2) in spine; -0.080 g/cm(2) in hip).

CONCLUSION

Depression is associated with low BMD, with a substantially greater BMD decrease in depressed women and in cases of clinical depression. Depression should be considered as an important risk factor for osteoporosis.

Chemistry and quality of Hibiscus (Hibiscus sabdariffa) for developing the natural-product industry in Senegal

The objectives of this study were to assess and improve the quality of the hibiscus calyces from Senegal over 2 production seasons (2004 to 2005), to develop and adapt new procedures for the determination of hibiscus anthocyanins and analysis of the 2 major ones, delphinidin-3-sambubioside and cyanidin-3-sambubioside. The foreign matter, total ashes, and acid insoluble ashes showed that the calyces harvested in 2005 were produced following hygienic practices, while the color assessment of the calyces and analysis of hibiscus active principles also showed higher amounts of anthocyanins in 2005. A protocol to measure anthocyanins by pH-differential UV-Vis spectrophotometry was adapted to measure the hibiscus anthocyanins from a water extract. The spectrophotometric method for quantitation of total anthocyanins showed a close correlation (r(2)= 0.82) when compared with the HPLC method, suggesting the use of the colorimetric method in quality control programs as an affordable alternative method to assess anthocyanin content in hibiscus. New and raised standards for the cleanliness and active principle content in hibiscus are also proposed. This study demonstrated that the implementation of a quality control program and the application of agricultural good practices in the production and processing of hibiscus calyces can lead to higher quality natural plant products.

Direct visualization of optical frequency invisibility cloak based on silicon nanorod array

A new invisibility cloak was recently proposed for hiding objects in front of a highly reflecting mirror. This cloak requires only modest values of optical constants with minimal anisotropy and thus can be implemented by using non-resonant dielectric materials, making it an ideal system for optical frequency operation. We implemented the cloak using an array of silicon nanorods fabricated by electron-beam lithography. We then directly visualized the cloaking effect by monitoring the light propagation inside the device using the near-field optical microscopy.

A low dose of Mycoplasma pneumoniae infection enhances an established allergic inflammation in mice: the role of the prostaglandin E2 pathway

BACKGROUND

Over 40% of chronic stable asthma patients have evidence of respiratory Mycoplasma pneumoniae (Mp) infection as detected by PCR, but not by serology and culture, suggesting that a low-level Mp is involved in chronic asthma. However, the role of such a low-level Mp infection in the regulation of allergic inflammation remains unknown.

OBJECTIVE

To determine the impact of a low-level Mp infection in mice with established airway allergic inflammation on allergic responses such as eosinophilia and chemokine eotaxin-2, and the underlying mechanisms [i.e. the prostaglandin E(2) (PGE(2)) pathway] since PGE(2) inhalation before an allergen challenge suppressed the eosinophil infiltration in human airways.

METHODS

BALB/c mouse models of ovalbumin (OVA)-induced allergic asthma with an ensuing low- or high-dose Mp were used to assess IL-4 expression, bronchoalveolar lavage (BAL) eosinophil, eotaxin-2 and PGE(2) levels, and lung mRNA levels of microsomal prostaglandin E synthase-1 (mPGES-1). Primary alveolar macrophages (pAMs) from naïve BALB/c mice were cultured to determine whether Mp-induced PGE(2) or exogenous PGE(2) down-regulates IL-4/IL-13-induced eotaxin-2.

RESULTS

Low-dose Mp in allergic mice significantly enhanced IL-4 and eotaxin-2, and moderately promoted lung eosinophilia, whereas high-dose Mp significantly reduced lung eosinophilia and tended to decrease IL-4 and eotaxin-2. Moreover, in both OVA-naïve and allergic mice, lung mPGES-1 mRNA and BAL PGE(2) levels were elevated in mice infected with high-dose, but not low-dose Mp. In pAMs, IL-4/IL-13 significantly increased eotaxin-2, which was reduced by Mp infection accompanied by dose-dependent PGE(2) induction. Exogenous PGE(2) inhibited IL-4/IL-13-induced eotaxin-2 in a dose-dependent manner.

CONCLUSIONS

This study highlights a novel concept on how different bacterial loads in the lung modify the established allergic airway inflammation and thus interact with an allergen to further induce Th2 responses. That is, unlike high-level Mp, low-level Mp fails to effectively induce PGE(2) to down-regulate allergic responses (e.g. eotaxin-2), thus maintaining or even worsening allergic inflammation in asthmatic airways.

Development of monoclonal antibody-coated immunomagnetic beads for separation and detection of norovirus (genogroup II) in faecal extract samples

AIMS

The aim of this study is to develop an RT-PCR assay combined with immunomagnetic beads (IMS/RT-PCR) coating monoclonal antibody (Mab) for separation and detection of norovirus (genogroup II) in faecal samples. We furthermore compare its detection limits with IMS/RT-PCR using polyclonal antibody (Pab) and the TRIzol extraction method followed by RT-PCR (TRIzol-RT-PCR).

METHODS AND RESULTS

Mab-coated beads and Pab-coated beads were added to a series of tenfold dilutions of faecal extract containing norovirus in 1 ml PBS. After incubation and collection, the RNA was released by heating from virus separated by beads. The tenfold dilutions of faecal were also extracted with TRIzol reagent. The RNA was used as the template for RT-PCR detection (primers: JV12-JV13). IMS/RT-PCR using Mab showed an endpoint in the 10(-7) dilution and was 10(2) times more sensitive than IMS/RT-PCR using Pab and was at least 10(3) times more sensitive than TRIzol-RT-PCR method.

CONCLUSIONS

IMS/RT-PCR using Mab proved to be a more sensitive method of noroviruses (NVs) detection than IMS/RT-PCR using Pab and the TRIzol-RT-PCR method.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to detect NVs with IMS/RT-PCR using Mab, and could serve as a model for future assays when broadly reactive NVs-specific Mabs are developed.