Resolution of airway inflammation following ovalbumin inhalation: comparison of ISS DNA and corticosteroids

In this study we have compared the therapeutic effect of the administration of immunostimulatory DNA sequences (ISS) with that of corticosteroids on the resolution of airway inflammation and airway hyperreactivity (AHR) in a mouse model. Mice which had already developed significant levels of eosinophilic airway inflammation 24 h after allergen challenge were then treated with either ISS or corticosteroids, and the effect on AHR and airway inflammation assessed 6 d later. ISS inhibited AHR as effectively as corticosteroids. Combination therapy with ISS and corticosteroids was more effective than monotherapy with either ISS or corticosteroids in inhibiting AHR. In ovalbumin-challenged mice, levels of bronchoalveolar lavage (BAL) eosinophils were significantly reduced with either ISS or corticosteroids. ISS induced significant levels of BAL interferon-gamma, whereas corticosteroids did not induce expression of BAL interferon-gamma. Both ISS and corticosteroids significantly reduced levels of interleukin-5 in BAL, as well as the number of Periodic Acid Schiff-positive airway epithelial cells. Corticosteroids, but not ISS, increased the number of eosinophils in regional mediastinal lymph nodes. Very few apoptotic peribronchial cells were noted following ovalbumin challenge as assessed by TUNEL assay. Corticosteroids, but not ISS, induced an increase in the small number of apoptotic peribronchial cells. The mechanism by which either ISS or corticosteroids inhibit AHR is likely to be mediated by distinct and shared cellular pathways. The combination of the shared and distinct anti-inflammatory pathways may account for the additive effect of ISS and corticosteroids on inhibiting AHR.     

Effects of surfactants on the properties of PLGA nanoparticles

The objective of this study was to investigate the physical characteristics of poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) coated with two surfactants, Pluronic or the commonly used polyvinyl alcohol (PVA); and determine their in vitro efficiency as drug carriers for cancer therapy. Free surfactant cytotoxicity results indicated that Pluronic F127 (PF127) was most cytocompatible among the Pluronics tested and hence chosen for coating PLGA NPs for further studies. Release studies using doxorubicin (DOX) as a drug model showed sustained release of DOX from both PVA- and PF127-coated PLGA NPs (PLGA-PVA and PLGA-PF127, respectively) over 28 days. Further, there was no significant difference in human dermal fibroblasts and human aortic smooth muscle cell survival when exposed to both types of NPs. Cellular uptake studies demonstrated that uptake of both nanoparticle types was dose-dependent for both prostate and breast cancer cells. However, these cancer cells internalized more PLGA-PF127 NPs than PLGA-PVA NPs. Moreover, studies showed that drug-loaded PLGA-PF127 NPs not only killed more cancer cells than drug-loaded PLGA-PVA NPs, but also overcame drug resistance in LNCaP, MDA-MB-231, and MDA-MB-468 cancer cells on re-exposure. These results indicate that PLGA-PF127 NPs can form a promising system that not only delivers anti-cancer drugs, but also overcomes drug resistance, which is prevalent in most cancer cells.     

The effect of smoking on the ocular surface and the precorneal tear film

Background

Smoking, both active and passive, creates a plethora of health-related problems, which primarily affect the cardiovascular and respiratory systems. There is very little evidence on the effects of tobacco smoke on the eye, especially regarding anterior ocular surface related pathology. This study was undertaken to determine the effects of smoking on the ocular surface and the tear film in smokers.

Methods

A total of 51 (102 eyes) smokers and 50 (100 eyes) age-and gender-matched healthy non-smokers were included in this study. The ocular surface was evaluated by measuring tear film break-up time, surface staining with fluorescein, and corneal and conjunctival sensitivities, and by completing the Schirmer''s II test. Data was analysed using Statistical Package for Social Sciences (SPSS) version 11.5. A p value less than 0.05 was considered statistically significant.

Results

The smoker group had significantly lower tear film break-up time, and corneal and conjunctival sensitivity than the nonsmoker group. Punctate staining was significantly higher in the smoker group than the non-smoker group. There was no statistically significant difference in Schirmer''s II test results between the smoker and non-smoker group.

Conclusion

Smoking caused adverse effects on the precorneal tear film and there was strong association between smoking and tear film instability. Although a causative relationship could not be determined, there is a need for further longitudinal studies.     

Ability to delay neuropathological events associated with astrocytic MAO-B increase in a Parkinsonian mouse model: implications for early intervention on disease progression

We previously demonstrated that elevation of astrocytic monoamine oxidase B (MAO-B) levels in adoxycycline (dox)-inducible transgenic mouse model following 14 days of dox induction results in several neuropathologic features similar to those observed in the Parkinsonian midbrain (Mallajosyula et al., 2008).These include a specific, selective and progressive loss of dopaminergic neurons of the substantia nigra (SN),selective decreases in mitochondrial complex I (CI) activity and increased oxidative stress. Here, we report that the temporal sequence of events following MAO-B elevation initially involves increased oxidative stress followed by CI inhibition and finally neurodegeneration. Furthermore, dox removal (DR) at days 3 and 5 of MAO-B induction was sufficient to arrest further increases in oxidative stress as well as subsequent neurodegenerative events. In order to assess the contribution of MAO-B-induced oxidative stress to later events, we compared the impact of DR which reverses the MAO-B increase with treatment of animals with the lipophilic antioxidant compound EUK-189. EUK-189 was found to be as effective as DR in halting downstream CI inhibition and also significantly attenuated SN DA cell loss as a result of astrocytic MAO-B induction. This suggests that MAO-B-mediated ROS contributes to neuropathology associated with this model and that antioxidant treatment can arrest further progression of dopaminergic cell death. This has implications for early intervention therapies.     

An evaluation of resampling methods for assessment of survival risk prediction in high-dimensional settings

Resampling techniques are often used to provide an initial assessment of accuracy for prognostic prediction models developed using high-dimensional genomic data with binary outcomes. Risk prediction is most important, however, in medical applications and frequently the outcome measure is a right-censored time-to-event variable such as survival. Although several methods have been developed for survival risk prediction with high-dimensional genomic data, there has been little evaluation of the use of resampling techniques for the assessment of such models. Using real and simulated datasets, we compared several resampling techniques for their ability to estimate the accuracy of risk prediction models. Our study showed that accuracy estimates for popular resampling methods, such as sample splitting and leave-one-out cross validation (Loo CV), have a higher mean square error than for other methods. Moreover, the large variability of the split-sample and Loo CV may make the point estimates of accuracy obtained using these methods unreliable and hence should be interpreted carefully. A k-fold cross-validation with k = 5 or 10 was seen to provide a good balance between bias and variability for a wide range of data settings and should be more widely adopted in practice.     

Assessment of microsatellite instability in colorectal carcinoma at an Indian center

Aim The purpose of the present study was to evaluate the frequency of microsatellite instability (MSI) in colorectal cancers in an Indian cohort. Materials and methods Paraffin embedded tissue samples of colorectal cancers from 46 patients were assessed for mismatch repair protein expression (hMLH1 and hMSH2) by immunohistochemistry. Subsequently, MSI analysis was done after PCR amplification of five Bethesda markers. Results Amongst 46 cases studied, only 5 patients (10.8%) showed MSI. Out of these, two (4.3%) had high microsatellite instability (MSI-H) and three (6.5%) showed low microsatellite instability (MSI-L). Out of 46 cases, 41 were microsatellite stable (MSS). In the 46 cases tested by immunohistochemistry, 7 (15.7%) showed the absence of hMLH1 and 1 case showed the absence of hMSH2. Conclusion Our study indicates a similar rate of incidence of MSI in colorectal cancers in the Indian cohort compared to the West (10–15%) despite lower incidence of colorectal cancers and predominance of rectosigmoid tumors in the Indian population.