Polymorphisms in oxidative stress-related genes and mortality in breast cancer patients--potential differential effects by radiotherapy?

We assessed whether variants in 22 oxidative stress-related genes are associated with mortality of breast cancer patients and whether the associations differ according to radiotherapy. Using a prospective cohort of 1348 postmenopausal breast cancer patients, we estimated hazard ratios (HR) and 95% confidence intervals (CI) for 109 single nucleotide polymorphisms (SNPs) using Cox proportional hazards regression. Validation of results was attempted using two Scandinavian studies. Eleven SNPs in MT2A, NFE2L2, NQO1, PRDX1, and PRDX6 were significantly associated with overall mortality after a median follow-up of 5.7 years. Three SNPs in NQO1 (rs2917667) and in PRDX6 (rs7314, rs4916362) were consistently associated with increased risk of dying across all three study populations (pooled: HRNQO1_rs2917667 1.20, 95% CI 1.00-1.44, p = 0.051; HRPRDX6_rs7314 1.16, 95% CI 1.00-1.35, p = 0.056, HRPRDX6_rs4916362 1.14 95% CI 1.00-1.32, p = 0.062). Potential effect modification by radiotherapy was found for CAT_rs769218. In conclusion, genetic variants in NQO1 and PRDX6 may modify breast cancer prognosis.

Effect of olive oil phenols on the production of inflammatory mediators in freshly isolated human monocytes

Recent in vitro and in vivo studies suggest that the anti-inflammatory properties of extra virgin olive oil may be involved in the prevention of chronic degenerative diseases. In this study, the ability of olive oil phenols to influence the release of superoxide anions (O2-), prostaglandin E2 (PGE2) and tumor necrosis factor α (TNFα) and the expression of cyclooxygenase2 (COX2) in human monocytes, freshly isolated from healthy donors, was investigated. O2- were measured by superoxide dismutase-inhibitable cytochrome c reduction and PGE2 and TNFα production were determined in culture medium with appropriate enzyme immunoassay kits. COX2 mRNA and protein were evaluated by quantitative reverse transcription-polymerase chain reaction and Western immunoblotting, respectively. Treatment of monocytes for 24 h with 100 μM of hydroxytyrosol (3,4-DHPEA), tyrosol (p-HPEA) and their secoiridoid derivatives (3,4-DHPEA and p-HPEA linked to the dialdehydic form of elenolic acid: 3,4-DHPEA-EDA and p-HPEA-EDA, respectively) significantly (P<.05) inhibited the production of O2(-) as follows: 3,4-DHPEA (40%,), p-HPEA (9%), 3,4-DHPEA-EDA (25%) and p-HPEA-EDA (36%). Hydroxytyrosol also considerably reduced the expression of COX2 at both the mRNA and protein level (P<.05) and caused a clear dose-dependent reduction of PGE2 released into the culture medium (45% and 71% at 50 and 100 μM, respectively, P<.05). The COX2 mRNA was also efficiently inhibited by the secoiridoids. Moreover, it was shown that hydroxytyrosol increased the monocytes TNFα production. In addition to other chemopreventive properties, these results suggest that the health effects of olive oil phenols may be related to their ability to modulate the production of pro-inflammatory molecules, a property common to non-steroidal anti-inflammatory drugs.

Protective effect of lycopene against ochratoxin A induced renal oxidative stress and apoptosis in rats

This study was designed to investigate the possible protective effect of lycopene against the renal toxic effects of OTA. Male Sprague-Dawley rats (<200 g, n=6) were treated with OTA (0.5 mg/kg/day) and/or lycopene (5 mg/kg/day) by gavage for 14 days. Histopathological examinations were performed and apoptotic cell death in both cortex and medulla was evaluated by TUNEL assay. Besides, biochemical parameters and activities of renal antioxidant selenoenzymes [glutathione peroxidase 1 (GPx1), thioredoxin reductase (TrxR)], catalase (CAT), superoxide dismutase (SOD); concentrations of total glutathione (GSH), and malondialdehyde (MDA) levels were measured. OTA treatment was found to induce oxidative stress in rat kidney, as evidenced by marked decreases in CAT (35%) activity and GSH levels (44%) as well as increase in SOD activity (22%) vs control group. Furthermore, TUNEL analysis revealed a significant increase in the number of TUNEL-positive cells in cortex (49%) and medulla (75%) in OTA administrated group compared to control (p<0.05). Lycopene supplementation with OTA increased GPx1 activity and GSH levels, and decreased apoptotic cell death in both cortex and medulla vs. control. The results of this study showed that at least one of the mechanisms underlying the renal toxicity of OTA is oxidative stress and apoptosis is the major form of cell death caused by OTA. Besides, our data indicate that the natural antioxidant lycopene might be partially protective against OTA-induced nephrotoxicity and oxidative stress in rat.

A mechanism of retinal protection from light-induced degeneration by hydrogen sulfide

Since our initial demonstrations that hydrogen sulfide (H(2)S) may function as a neuromodulator in the brain and a smooth muscle relaxant in the vascular system, accumulating evidence shows that H(2)S may function as a signaling molecule. We and others also found that H(2)S has a cytoprotective effect. Because H(2)S is well-known toxic gas, a cytoprotective role has been overlooked. H(2)S protects neurons from oxidative stress. It also protects cardiac muscle from ischemia-reperfusion injury. The finding led to the application of H(2)S to the bypass surgery patients in Phase II clinical trial. Cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) are well known as H(2)S-producing enzymes. We recently demonstrated that the other H(2)S-producing enzyme, 3-mercaptopyruvate sulfurtransferase (3MST) along with cysteine aminotransferase (CAT) is localized to neurons in the brain and to the vascular endothelium. However, the regulation of H(2)S production by 3MST/CAT pathway had not been well understood. The present study shows that H(2)S production by 3MST/CAT pathway is regulated by Ca(2+) and that H(2)S protects retinal photoreceptor cells from light induced degeneration by suppressing excessive Ca(2+) influx caused by intense light.

Multidimensional CAT Item Selection Methods for Domain Scores and Composite Scores: Theory and Applications

Multidimensional computer adaptive testing (MCAT) can provide higher precision and reliability or reduce test length when compared with unidimensional CAT or with the paper-and-pencil test. This study compared five item selection procedures in the MCAT framework for both domain scores and overall scores through simulation by varying the structure of item pools, the population distribution of the simulees, the number of items selected, and the content area. The existing procedures such as Volume (Segall in Psychometrika, 61:331-354, 1996), Kullback-Leibler information (Veldkamp & van der Linden in Psychometrika 67:575-588, 2002), Minimize the error variance of the linear combination (van der Linden in J. Educ. Behav. Stat. 24:398-412, 1999), and Minimum Angle (Reckase in Multidimensional item response theory, Springer, New York, 2009) are compared to a new procedure, Minimize the error variance of the composite score with the optimized weight, proposed for the first time in this study. The intent is to find an item selection procedure that yields higher precisions for both the domain and composite abilities and a higher percentage of selected items from the item pool. The comparison is performed by examining the absolute bias, correlation, test reliability, time used, and item usage. Three sets of item pools are used with the item parameters estimated from real live CAT data. Results show that Volume and Minimum Angle performed similarly, balancing information for all content areas, while the other three procedures performed similarly, with a high precision for both domain and overall scores when selecting items with the required number of items for each domain. The new item selection procedure has the highest percentage of item usage. Moreover, for the overall score, it produces similar or even better results compared to those from the method that selects items favoring the general dimension using the general model (Segall in Psychometrika 66:79-97, 2001); the general dimension method has low precision for the domain scores. In addition to the simulation study, the mathematical theories for certain procedures are derived. The theories are confirmed by the simulation applications.

Novel sutureless transplantation for primary pterygium associated with cysts

AIM

To evaluate the efficacy and safety of a novel sutureless AMT (amniotic membrane transplantation) or CAT (conjunctivolimbal autograft transplantation) using fibrin glue for reconstructing corneoconjunctival surfaces for primary pterygium associated with cysts.

METHODS

A prospective descriptive study was made of the period 1 January 2006-1 May 2009. Nine patients with primary pterygium associated with cysts underwent pterygium and cyst excision followed by sutureless AMT or CAT using fibrin glue.

RESULTS

During a mean follow-up of 8.00±0.67 months, all eyes maintained a smooth and stable corneal epithelial surface without recurrent erosion or persistent epithelial defect. The limbal donor site showed the presence of mild depressions without the formation of pseudopterygium. All eyes have good tear secretion function, tear film stability and ocular motility.

CONCLUSION

Sutureless transplantation using fibrin glue is safe and effective for restoring a stable corneoconjunctival epithelium in primary pterygium associated with cysts.