Sunscreen Label Marketing Towards Pediatric Populations: Guidance for Navigating Sunscreen Choice.

INTRODUCTION:  Sunscreen marketing to specific demographics is largely unregulated. Marketing specifically targeting pediatric populations has the potential to drive consumer behavior. The American Academy of Pediatrics (AAP) and American Academy of Dermatology (AAD) provide recommendations for sunscreen use in children over the age of six months. This study sought to determine if sunscreen products marketed toward pediatric populations align with healthcare guidelines. MATERIALS AND METHODS: Sunscreens available in major retail outlets in the Philadelphia area were cataloged and reviewed for marketing targeting specific demographics such as "baby", "babies", "children", "kids", "sports", and "active". The products were reviewed for sun protection factor (SPF), broad-spectrum ultraviolet (UV) protection, water resistance, active UV filters, and application method.  Results: Of 410 sunscreens cataloged, 27 were marketed towards "baby" or "babies", 44 towards "children" or "kids", and 71 towards "sports" or "active". All of the sunscreen products reviewed targeting the pediatric population offered water resistance for up to 80 minutes and broad-spectrum UV coverage. Sunscreens targeting "baby" or "babies" aligned most closely with AAP guidelines for sunscreen use in pediatric populations, with 92.6% offering an SPF between 15 to 50 and no products including oxybenzone as a UV filter. However, sunscreens targeting "children", "kids", "sports", and "active" bore a close resemblance to the overall sunscreen profile for all demographics but with a higher percentage of products containing oxybenzone. Oxybenzone was found in 11.4% of "children" and "kids" products and 16.9% of "sports" and "active" sunscreen products, compared to 7.6% of all sunscreen products available, and was also found in most sunscreen products with an SPF of 70 or higher. CONCLUSION:  Sunscreen products marketed towards "baby" and "babies" tend to align closely with guidelines for sunscreen use in the pediatric population for children over six months of age; however, those with brand marketing towards "children", "kids", "sports", and "active" do not. Limiting recommendations for a sunscreen product with an SPF of 30 to 50 targeting this demographic, however, sufficiently meets guidelines set forth by the AAP and AAD.

Availability of Adequate Photoprotection for Skin of Color.

INTRODUCTION: The impact of ultraviolet (UV) light on the skin is well-established to have both immediate and delayed effects with increasing awareness of the impact of visible light (VL) on the skin with regard to photoaging and dyspigmentation. The effects of VL disproportionately impact the skin of color with regard to discoloration of the skin leading to guidelines for photoprotection that include the use of iron oxides in sunscreen products that impart a tint. METHODS: Commercially available sunscreen products found in the suncare and sun protection displays at local stores, pharmacies, and grocery stores were cataloged, and ingredients were reviewed for the presence of iron oxides. RESULTS: Of the 410 commercially available sunscreen products cataloged, 1.7% of facial sunscreen products available offered iron oxides, and 0.5% of non-lip products offered shade matching. CONCLUSION: With only 1.7% of commercially available facial sunscreen products offering iron oxides in addition to traditional broad-spectrum UV protection, there is a clear gap in the market for iron oxide-containing sunscreen products to meet the photoprotection needs for the skin of color.

Assessment of UV Protection for Children's Summer Clothing.

INTRODUCTION:  Excess ultraviolet (UV) radiation exposure during childhood poses a particular long-term risk of developing skin cancer later in life however recent studies have called attention to the absorption of chemical sunscreen ingredients into the bloodstream with unclear significance. This has led to recommendations to consider sun protection in the form of clothing to reduce the need for sunscreen products. METHODS:  Ten brands of routine summer clothing not labeled as sun protective from five distributors marketed for children were identified with varying price ranges. Summer clothing items consisting of T-shirts and tops were evaluated for fiber composition, cost, and UPF testing was performed to determine UVA and UVB transmittance.  Results: Around 88.2% of blended textile compositions compared to 60% of 100% cotton textiles offered adequate UV protection with an Ultraviolet Protection Factor (UPF) greater than 15. 58% of blended fabrics compared to 50% of cotton textiles offered a UPF greater than 30. There was no correlation between brand and cost with UPF values.  Conclusions: In the absence of regulations for testing and labeling of all children's garments for UV protection, guidelines for the pediatric population for choosing clothing for the summer should reflect the information available to consumers that is easy to understand and more likely to result in higher UPF values. Based on fiber composition, blended textiles are more likely to have adequate UV protection compared to 100% cotton or 100% polyester.

Chemical Hypoxic Preconditioning Improves Survival and Proliferation of Mesenchymal Stem Cells.

Increasing evidence has demonstrated that mesenchymal stem cells (MSCs) have been linked to tissue regeneration both in vitro and in vivo. However, poor engraftment and low survival rate of transplanted MSCs are still a major concern. It has been found that the proliferation, survival, and migration of MSCs are all increased by hypoxic preconditioning. However, the molecular mechanism through which hypoxic preconditioning enhances these beneficial properties of MSCs remains to be fully investigated. Therefore, the present study is aimed to investigate the mechanism by which hypoxic preconditioning enhances the survival of MSCs. We used proteomic analysis to explore the molecules that may contribute to the survival and proliferation of hypoxic preconditioned (HP) MSCs. The analysis revealed a higher expression of prelamin A/C (Lmna), glutamate dehydrogenase 1(Glud1), Actin, cytoplasmic 1(Actb), Alpha-enolase (Eno1), Glucose-6-phosphate 1-dehydrogenase (G6pd), Protein disulfide-isomerase A3 (Pdia3), Malate dehydrogenase (Mdh1), Peroxiredoxin-6 (Prdx6), Superoxide dismutase (Sod1), and Annexin A2 (Anxa2) in HP-MSCs. These proteins are possibly involved in cellular survival and proliferation through various cellular pathways. This research could aid in understanding the processes involved in hypoxic preconditioning of MSCs and designing of cell-based therapeutic strategies for tissue regeneration.

Differential Protein Expression in Response to Varlitinib Treatment in Oral Cancer Cell Line: an In Vitro Therapeutic Approach.

Epidermal growth factor receptor (EGFR) is the most frequently overexpressed receptor histologically exhibited by oral squamous cell carcinoma (OSCC) patients. Aberrated EGFR signaling may lead to recurrence and metastasis, thus laying the foundation of targeted therapy. Deactivating EGFR is likely to prevent downstream signaling thus resulting in apoptosis. Tyrosine kinase inhibitors (TKIs) have come into play to revert aggressiveness of OSCC. We exploited comparative proteomic analyses based on anti-EGFR potential of varlitinib, using cellular proteomes from treated and untreated groups of oral cancer cells to identify protein players functional during oral carcinogenesis. Following separation by two-dimensional electrophoresis, differentially expressed cellular proteins (varlitinib-treated and untreated cells) were analyzed and later identified using QTOF mass spectrometer. In silico analysis for protein-protein interaction was carried out using STRING. Six differentially expressed proteins were identified as binding immunoglobulin protein (BiP), heat shock protein 7 C (HSP7C), protein disulfide isomerase 1 A (PDIA1), vimentin (VIME), keratin type I cytoskeletal 14 (K1C14), and ß-Actin (ACTB). Relative expression of five proteins was found to be downregulated upon varlitinib treatment, whereas only K1C14 was upregulated in treated cells compared to control. Protein network analysis depicts the interaction between BiP, PDIA1, VIME, etc. indicating their role in oral carcinogenesis. Oral cancer cells show proteome shift based on varlitinib treatment compared to corresponding controls. Our data suggest candidature of varlitinib as a potent therapeutic agent and BiP, PDIA1, HSP7C, VIME, and ß-Actin as complementary/prognostic markers of OSCC.

Polymorphic Variants of ASS1 Gene Related to Arginine Metabolism and the Risk of HCC.

BACKGROUND: Hepatocellular carcinoma is a primary liver cancer and 6th most common cancer globally. Inefficient diagnostic strategies and the limited availability of treatments are the foremost reasons. Variable factors directly impact the disease burden, among them, molecular alterations have been found to play a significant role. In liver, argininosuccinate synthase-1 is a center of arginine metabolism and rate limiting enzyme of urea cycle. It also triggers multiple mechanisms that lead to HCC pathogenesis. OBJECTIVES: The aim of this study is to analyze the ASS1 gene expression, its polymorphic genotype and microsatellite instability among HCC patients from our Pakistani population. METHOD: Blood samples were collected from disease and healthy control individuals. Allele-Specific PCR was performed for SNP analysis. MSI of tri and tetra nucleotide repeats were analyzed by PCR. The differential expression of ASS1 gene was also investigated. Furthermore, the reactome database and STRING software were utilized for finding correlations between ASS1 gene with other associated gene/proteins. RESULTS: The GG wild-type genotype was more prevailed in the disease group as compared to the control. Significant downregulation in ASS1 and NOS2 genes was observed. Bioinformatics analysis reveals the correlation between ASS1 polymorphism and HCC development appears to be linked with the EMT pathway and polyamine production. Furthermore, MSI significantly resided in the disease group. Results were analyzed statistically to calculate the significance of obtained results. CONCLUSION: Study concludes that the insight of HCC mechanism through population-specific genetic mutations and altered gene expression of ASS1 might be helpful in early diagnostic and therapeutic purposes.

Novel Synergistic Combination of Pamidronate and Temozolomide for Breast Cancer Therapeutics.

OBJECTIVE: Human breast cancer is among one major health concerns with high prevalence and mortality among women worldwide. Various cellular signaling pathways are implicated in carcinogenesis. One of the major pathways that affect the downstream cellular growth cascades is Mevalonate pathway (MVA). The inhibition of MVA is therapeutically beneficial for various cancers. Pamidronate (PAM) (MVA inhibitor), a nitrogen-containing bisphosphosphonate, is an antiresorptive FDAapproved drug. The objective of our study was to explore adjuvant therapy using a combination of PAM and an alkylating agent, Temozolomide (TMZ) against breast cancer. METHODS: We have examined the differential gene and protein expression in response to the combination treatment strategy. For gene expression analysis RT-qPCR and for proteomic study, twodimensional gel electrophoresis and mass spectrometry techniques were utilized. RESULTS: Combination treatment (PAM+TMZ) showed more pronounced cytotoxic effect as compared to single agent treatment. Our results indicate that MVA pathway regulatory genes (FDFT1, FDPS, KRAS) are significantly (p<0.05) downregulated in combination-treated breast cancer cells. The differential proteomic analysis showed lower expression of GFAP, PPA1 and TRIM68 proteins after synergistic treatment whereas, these proteins are found to be up-regulated in multiple cancers. CONCLUSION: The present study reveals that a combination of PAM and TMZ produces an effective anti-cancerous effect on breast cancer cells. Therefore, this novel therapeutic regimen is likely to provide a better treatment strategy for breast cancer.

Oxidative Stress Induced Cell Cycle Arrest: Potential Role of PRX-2 and GSTP-1 as Therapeutic Targets in Hepatocellular Carcinoma.

BACKGROUND: The increasing incidence and mortality rate of HCC is a major concern, especially for developing countries of the world. Hence, extensive research is being carried out in order to explore new approaches for developing successful therapeutic strategies for HCC. The controversial role of oxidative stress in the prognosis and treatment of various diseases such as cancer has become an area of great interest and intrigue for many scientists throughout the world. OBJECTIVE: We aim to investigate the role of induced oxidative stress on the suppression of HCC Huh-7 cancerous cells as a therapeutic approach. METHODS: Induction of oxidative stress via H2O2 treatment produced cell cytotoxicity in a dose dependent manner and also led to the overexpression of GSTP-1 and PRX-2. The expression of GSTP- 1 and PRX-2 was compared in HCC Huh-7 treated, untreated cells and normal hepatocytes using immunocytochemistry. Furthermore, the effects of oxidative stress on cell cycle arrest were also studied through flow cytometry. RESULTS: Our study demonstrated the inhibition of cancer cell proliferation as a result of H2O2 induction by arresting the cell cycle at the G2 phase. CONCLUSION: The induction of oxidative stress could be a potential therapeutic approach for treating HCC in the future. GSTP-1 and PRX-2 can serve as substantial therapeutic targets for the treatment of HCC.

Serum HSP90-Alpha and Oral Squamous Cell Carcinoma: A Prospective Biomarker.

AIM: This study aims to perform differential protein expression analysis of serum samples from Oral Squamous Cell Carcinoma (OSCC) patients and healthy controls in search of potential diagnostic and/or prognostic biomarker(s). OBJECTIVE: OSCC is usually diagnosed late, which results in poor survival and high mortality. Identification of non-invasive prognostic biomarkers is of utmost importance for early diagnosis and proper management of the disease; hence we used a proteomic approach to identify potential biomarkers from serum. METHODS: Serum samples (OSCC n=45 and control n=30) were depleted, and proteins were separated using 2-D gel electrophoresis followed by identification by mass spectrometric analysis. Gene expression analysis of identified proteins in malignant and normal tissue was also performed to complement proteomics studies. RESULTS: Among differentially expressed proteins, up-regulation of heat shock protein alpha (HSP90α) from the serum of oral cancer patients was observed. We also observed elevated levels of Haptoglobin (HP) along with downregulation of Type II keratin cytoskeletal 1(KRT1) and serum albumin (ALB) in oral cancer patients. Gene expression studies on identified proteins in malignant and normal tissue revealed a similar pattern with the exception of KRT1. We believe that elevated levels of serum HSP90 alpha might be used as a potential biomarker. CONCLUSION: Our findings suggest a contribution of HSP90 alpha and other identified proteins in oral pathology as pro/anti-apoptotic modulators, thus considering their potential as predictive biomarkers.

Effect of valproic acid on the hepatic differentiation of mesenchymal stem cells in 2D and 3D microenvironments.

Mesenchymal stem cells (MSCs) have multi-lineage differentiation potential which make them an excellent source for cell-based therapies. Histone modification is one of the major epigenetic regulations that play central role in stem cell differentiation. Keeping in view their ability to maintain gene expression essential for successful differentiation, it was interesting to examine the effects of valproic acid (VPA), a histone deacetylase inhibitor, in the hepatic differentiation of MSCs within the 3D scaffold. MSCs were treated with the optimized concentration of VPA in the 3D collagen scaffold. Analyses of hepatic differentiation potential of treated MSCs were performed by qPCR, immunostaining and periodic acid Schiff assay. Our results demonstrate that MSCs differentiate into hepatic-like cells when treated with 5 mM VPA for 24 h. The VPA-treated MSCs have shown significant upregulation in the expression of hepatic genes, CK-18 (P < 0.05), TAT (P < 0.01), and AFP (P < 0.001), and hepatic proteins, AFP (P < 0.05) and ALB (P < 0.01). In addition, acetylation of histones (H3 and H4) was significantly increased (P < 0.001) in VPA-pretreated cells. Further analysis showed that VPA treatment significantly enhanced (P < 0.01) glycogen storage, an important functional aspect of hepatic cells. The present study revealed the effectiveness of VPA in hepatic differentiation within the 3D collagen scaffold. These hepatic-like cells may have an extended clinical applicability in future for successful liver regeneration.

Therapeutic effect of hydrogen peroxide via altered expression of glutathione S-transferase and peroxiredoxin-2 in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) has a high incidence and mortality that epitomizes one of the prominent causes of cancer-related death globally. Novel therapeutic approaches are therefore required. Reactive oxygen species (ROS) are necessary for maintaining cell cycle. Although ROS is involved in HCC progression, hydrogen peroxide (H2O2) has anti-proliferative effect on HCC. METHOD: HCC Huh-7 cells were cultured and incubated with various concentrations of H2O2. Paraoxonase activity, levels of malondialdehyde, glutathione and protein oxidation were measured in treated and untreated Huh-7 cells. Furthermore, untreated and treated Huh-7 cells were subjected to two dimensional gel electrophoresis and identified protein spots which were differentially expressed by LC-MS/MS analysis. qRT-PCR was performed to validate the identified proteins. RESULTS: H2O2 depleted glutathione (GSH) with the concomitant up-regulation of GSTP1 and Prx2. H2O2 also increased malondialdehyde and protein oxidation, decreased the activity of paraoxonase in Huh-7 cells. CONCLUSION: H2O2 could be used as a novel therapeutic agent that might be beneficial in inducing cell cytotoxicity and hence suppress HCC proliferation.

Role of magnetic resonance cholangiopancreatography (MRCP) in learning anatomical variations in pancreatic duct.

OBJECTIVE: To assess the frequency of anatomical variations of pancreatic duct through magnetic resonance cholangiography pancreatography. . METHODS: The cross-sectional prospective study was conducted from May 2011 to December 2012 at the Department of Anatomy, Institute of Basic Medical Sciences (IBMS), Dow University of Health Sciences, Karachi, in collaboration with the Department of Radiology, Aga Khan University Hospital, Karachi. The study comprised diagnosed cases of pancreato-biliary disease booked for magnetic resonance cholangiography pancreatography. Images were obtained using 1.5 Tesla magnetic resonance imaging scanner, and information of anatomical variations visualised on the imaging film was assessed and documented. RESULTS: Of the 377 subjects, 196(52%) were females and 181(48%) were males. Pancreas divisum was found in 21(5.6%) subjects; 13(62%) females and 8(38%) males. . Duct of Santorini was detected in 3(0.8%) subjects; 2(66.6%) females and 1(33.3%) male. CONCLUSIONS: Variations in pancreatic duct could be identified by using the simple, non-invasive method of magnetic resonance cholangiography pancreatography.

Identification of Differentially Expressed Proteins from Smokeless Tobacco Addicted Patients Suffering from Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is the eight most common malignancy worldwide with an incidence rate of 40% in south-east Asia. Lack of effective diagnostic tools at early stage and disease recurrence despite extensive treatments are main reasons for high mortality and low survival rates. The aim of current study was to identify differentially expressed proteins to explore potential candidate biomarkers having diagnostic significance. We performed comparative proteomic analysis of paired protein samples (cancerous buccal mucosa and adjacent normal tissue) from OSCC patients using a combination of two dimensional gel electrophoresis and Mass spectrometric analysis. On the basis of spot intensity, seventeen proteins were found to be consistently differentially expressed among most of the samples which were identified through mass spectrometry. For validation of identified proteins, expression level of stratifin was determined using immuno-histochemistry and Western blot analysis. All identified proteins were analyzed by STRING to explore their interaction. Among uniquely identified proteins in this study, at least two candidate markers (Ig Kappa chain C region and Isoform 2 of fructose bisphosphate aldolase A) were found to be novel with respect to OSCC which can be explored further. Results presented in current study are likely to contribute in understanding the involvement of these molecules in carcinogenesis apart from their plausible role as diagnostic/prognostic markers.

Identification of GIMAP7 and Rabl3 as Putative Biomarkers for Oral Squamous Cell Carcinoma Through Comparative Proteomic Approach.

Oral squamous cell carcinoma (OSCC) accounts for more than 90% of all oral cancers and has been listed as sixth most common human cancer. Due to late diagnosis and insufficient therapeutic response among patients, the survival rate remains very low accentuating the importance of early diagnostic markers. The study aimed to identify differentially expressed proteins in search for putative serum biomarkers and drug targets. Serum samples (n = 45) were depleted and resolved on two dimensional gel electrophoresis. Among differentially expressed proteins, two were identified using MALDI-TOF mass spectrometry. Gene expression levels of identified proteins were quantified in malignant and normal tissue using RT-qPCR. To validate serum Rabl3 expression, sandwich ELISA was performed. Proteomics analysis revealed two proteins which were found to be associated with oral cancer. The expression of GIMAP7 was found to be down regulated in serum of patients suffering from oral cancer while the expression of Rabl3 was found to be up-regulated. Gene expression analysis in malignant tissue and adjacent normal tissue revealed the same pattern. Quantitative ELISA was used to validate expression of Rabl3 in serum from oral cancer patients and healthy subjects which demonstrated significant up-regulation in cancer patients. Findings in current study demonstrate differential expression of novel putative biomarkers GIMAP7 and Rabl3 in oral cancer which suggests their potential role in oral cancer pathology and can be considered as predictive biomarkers.

Alendronate and FTI-277 combination as a possible therapeutic approach for hepatocellular carcinoma: An in vitro study.

BACKGROUND: An important product of mevalonate pathway is downstream synthesis of isoprenoid units that has long been implicated in development and progression of tumor. It has been speculated that inhibition of protein prenylation might be therapeutically beneficial. The objective of current study was to evaluate antitumor potential of a novel therapeutic combination of mevalonate pathway inhibitors, FTI-277 and alendronate. We also examined differentially expressed proteins in response to treatment using proteomics approach. METHODS: Huh-7 cells were incubated with different concentrations of FTI-277 alone and in combination with alendronate. Differential protein and gene expression was examined through two dimensional gel electrophoresis and real-time quantitative polymerase chain reaction (qPCR), respectively. Proteins were identified using tandem mass spectrometry analysis. RESULTS: Treatment of hepatocellular carcinoma (HCC) cell line with FTI-277 alone showed cell death in a time and dose dependent manner while in combination with alendronate, a synergistic apoptotic effect at 24 h was observed. Proteomic studies on the 20 µmol/L FTI-277 and 5 µmol/L alendronate +20 µmol/L FTI-277 treated cells revealed altered expression of different proteins including peroxiredoxin 2 (Prx2), glutathione S transferase 1 (GSTP1), Rho GTPase activating protein (RhoGAP), triosephosphate isomerase (TPI), and heat shock protein 60 (HSP60). Down-regulated expression of Prx2 and GSTP1 in treated cells was also confirmed by real-time qPCR analysis. CONCLUSIONS: Combined treatment of FTI-277 and alendronate on Huh-7 HCC cells showed cell death suggesting their anticancer potential. Such treatment approaches are likely to offer new therapeutic strategies.

Effects of 5'-azacytidine and alendronate on a hepatocellular carcinoma cell line: a proteomics perspective.

Hepatocellular carcinoma (HCC) is the third leading cause of cancer related deaths around the world. Due to late diagnosis and development of drug resistance in patients suffering from HCC, development of more effective therapeutic strategies is inevitable. The aim of this study was to evaluate the combined apoptotic effect of 5'-Azacytidine (5'-AzaC) and alendronate (ALN) on Huh-7 HCC cell line and to explore differential expression at genomics and proteomics level. Incubation of HCC cell line with 5'-AzaC alone showed cell death in a time and dose dependent manner while in combination with ALN, increased cytotoxicity was observed. Up-regulation of CASP7(Caspase7) and LZTS1 (leucine zipper, putative tumor suppressor 1) and down-regulation of DNMT1(DNA (cytosine-5-)-methyltransferase 1) was noted in treated cells. Proteomic studies on the treated cells revealed altered expression of different proteins including peroxiredoxin 2 (Prx2), Annexin 5 (Anx5), Rho GTPase activating protein (RhoGAP), Nuclear factor-kappa B (NF-kB), tumor necrosis factor alpha-induced protein (TNF), triosephosphate isomerase (TPI), Glutathione S transferase (GSTP1) and Heat shock protein60 (HSP60). Our study demonstrated the cytotoxic effect of 5'-AzaC and ALN drug combination on Huh-7 HCC cells suggesting such combinations may be explored as a possible therapeutic approach. Current study revealed that Huh-7 HCC cells are sensitive to 5'-AzaC and ALN drug combination and such combination approaches could lead to the development of new therapeutic strategies. Furthermore, we also report the expression of Anx5 exclusively in untreated cancerous cell line indicating the possibility of being used as a potential therapeutic target and biomarker.

The effect of alendronate on proteome of hepatocellular carcinoma cell lines.

Cancer is a life threatening disorder effecting 11 million people worldwide annually. Among various types of cancers, Hepatocellular carcinoma (HCC) has a higher rate of mortality and is the fifth leading cause of cancer related deaths around the world. Many chemotherapeutic drugs have been used for the treatment of HCC with many side effects. These drugs are inhibitors of different cell regulatory pathways. Mevalonate (MVA) pathway is an important cellular cascade vital for cell growth. A variety of inhibitors of MVA pathway have been reported for their anticancerous activity. Bisphosphonates (BPs) are members of a family involved in the treatment of skeletal complications. In recent years, their anticancer potential has been highlighted. Current study focuses on exploring the effects of alendronate (ALN), a nitrogen containing BP, on hepatocellular carcinoma cell line using genomic and proteomics approach. Our results identified ten differentially expressed proteins, of which five were up regulated and five were down regulated in ALN treated cells. Furthermore, we also performed gene expression analysis in treated and control cell lines. The study may help in understanding the molecular mechanism involved in antitumor activity of ALN, identification of possible novel drug targets, and designing new therapeutic strategies for HCC.

Lactate dehydrogenase like crystallin: a potentially protective shield for indian spiny-tailed lizard (Uromastyx hardwickii) lens against environmental stress?

Taxon specific lens crystallins in vertebrates are either similar or identical with various metabolic enzymes. These bifunctional crystallins serve as structural protein in lens along with their catalytic role. In the present study, we have partially purified and characterized lens crystallin from Indian spiny-tailed lizard (Uromastyx hardwickii). We have found lactate dehydrogenase (LDH) activity in lens indicating presence of an enzyme crystallin with dual functions. Taxon specific lens crystallins are product of gene sharing or gene duplication phenomenon where a pre-existing enzyme is recruited as lens crystallin in addition to structural role. In lens, same gene adopts refractive role in lens without modification or loss of pre-existing function during gene sharing phenomenon. Apart from conventional role of structural protein, LDH activity containing crystallin in U. hardwickii lens is likely to have adaptive characteristics to offer protection against toxic effects of oxidative stress and ultraviolet light, hence justifying its recruitment. Taxon specific crystallins may serve as good models to understand structure-function relationship of these proteins.

Expression and activity of paraoxonase 1 in human cataractous lens tissue.

Paraoxonase 1 (PON1) is a high-density lipoprotein-associated enzyme that is believed to be involved in the protection against oxidative stress. There is evidence that paraoxonase activity is reduced in patients with diabetes and cataract. In the current study, we analyzed mRNA expression of PON1 as well as other members of the paraoxonase family, PON2 and PON3, in human cataractous lens samples. Our results indicate that only PON1 is expressed at the gene and protein levels in human lens tissues. We quantified MDA levels and measured PON1 (paraoxonase/arylesterase) enzymatic activities in subjects suffering from cataract due to aging and diabetes. Decreased PON1 activity was more pronounced in diabetic patients (p< 0.001) compared to senile subjects, which may be due to glycation and increased oxidative insult. To examine the structural alterations that occur in response to glycation, we constructed a three-dimensional model of PON1 and its glycated variant. Glycation at Lys70 and Lys75 is predicted to cause hindrance in binding of substrate to the active site of the enzyme.