d-galactose causes embryonic development arrest and placental development disorders in mice by increasing ROS and inhibiting SIRT1/FOXO3a axis.

INTRODUCTION: Does an elevation in d-Galactose (D-Gal) levels within the body contribute to abnormal embryonic development and placental dysfunction during pregnancy? METHODS: Mouse embryos were cultivated to the blastocyst stage under varying concentrations of D-Gal. The blastocyst formation rate was measured, and the levels of reactive oxygen species (ROS), sirtuin 1 (SIRT1), and forkhead box O3a (FOXO3a) in blastocysts were assessed. Mice were intraperitoneally injected with either saline or D-Gal with or without SRT1720. On the 14th day of pregnancy, the fetal absorption rate and placental weight were recorded. Placental levels of superoxide dismutase (SOD) and malondialdehyde (MDA) were determined. The expression of senescence-related factors, such as senescence-associated ß-galactosidase (SA-ß-gal) in the placenta was examined, and the expression of placental SIRT1, FOXO3a and p21 was evaluated by immunohistochemistry and Western blotting. RESULTS: D-Gal adversely affects early embryonic development in vitro, resulting in a decreased blastocyst formation rate. Furthermore, D-Gal downregulates SIRT1 and FOXO3a while increasing ROS levels in blastocysts. Concurrently, D-Gal induces placental dysfunction, characterized by an elevated fetal absorption rate, reduced placental weight, diminished SOD activity, and increased MDA content. The senescence-related factor SA-ß-gal was detected in the placenta, along with altered expression of placental SIRT1, FOXO3a, and p21. The SIRT1 agonist SRT1720 mitigated this damage by increasing SIRT1 and FOXO3a expression. DISCUSSION: The inhibition of early embryonic development and placental dysfunction induced by D-Gal may be attributed to the dysregulation of SIRT1. Activating SIRT1 emerges as a potentially effective strategy for alleviating the adverse effects of D-Gal exposure.

Toxoplasma gondii Induces Pyroptosis in Human Placental Trophoblast and Amniotic Cells by Inducing ROS Production and Activation of Cathepsin B and NLRP1/NLRP3/NLRC4/AIM2 Inflammasome.

Toxoplasma gondii infection in pregnant women may cause fetal anomalies; however, the underlying mechanisms remain unclear. The current study investigated whether T. gondii induces pyroptosis in human placental cells and the underlying mechanisms. Human placental trophoblast (BeWo and HTR-8/SVneo) and amniotic (WISH) cells were infected with T. gondii, and then reactive oxygen species (ROS) production, cathepsin B (CatB) release, inflammasome activation, and pyroptosis induction were evaluated. The molecular mechanisms of these effects were investigated by treating the cells with ROS scavengers, a CatB inhibitor, or inflammasome-specific siRNA. T. gondii infection induced ROS generation and CatB release into the cytosol in placental cells but decreased mitochondrial membrane potential. T. gondii-infected human placental cells and villi exhibited NLRP1, NLRP3, NLRC4, and AIM2 inflammasome activation and subsequent pyroptosis induction, as evidenced by increased expression of ASC, cleaved caspase-1, and mature IL-1ß and gasdermin D cleavage. In addition to inflammasome activation and pyroptosis induction, adverse pregnancy outcome was shown in a T. gondii-infected pregnant mouse model. Administration of ROS scavengers, CatB inhibitor, or inflammasome-specific siRNA into T. gondii-infected cells reversed these effects. Collectively, these findings show that T. gondii induces NLRP1/NLRP3/NLRC4/AIM2 inflammasome-dependent caspase-1-mediated pyroptosis via induction of ROS production and CatB activation in placental cells. This mechanism may play an important role in inducing cell injury in congenital toxoplasmosis.

Effects of phthalates on human chorionic trophoblast cells and mouse embryonic development.

Phthalate exposure is associated with reproductive health, but the mechanism is unclear. This study used human chorionic trophoblast epithelial cells (HTR8/Svneo cells) and mouse embryos as objects aims to explore the effects of phthalate plasticizers on germ cells and fertility and the possible signalling pathways. In the present study, high concentrations of MEHP for 24 h significantly inhibited the proliferation and viability of HTR8/SVneo cells. Compared with the negative control (NC) group, the MEHP medium and high concentration groups promoted the apoptosis of HTR8/SVneo cells and inhibited the cell cycle, HTR8/SVneo cells were blocked in G1/G0 phase and could not enter S phase, and cell meiosis was inhibited. Western blot experiments showed that there was no difference in the protein expression of wnt inhibitory factor 1 (WIF1) and ß-catenin in HTR8/SVneo cells between the MEHP exposure groups and the NC groups. In vitro embryo culture experiments found that there was no difference in blastocyst formation rate among groups after exposure to DEHP for 2 h. Immunofluorescence showed that the expression of WIF1 decreased in the low concentration group, and there was no difference in the medium and high concentration groups, while the expression of ß-catenin was increased in both the low concentration group and the high concentration group. Our data suggest that exposure to phthalate plasticizers can affect the viability, cell cycle and apoptosis of trophoblast cells, resulting in abnormal expression of the embryonic WIF1/ß-catenin signalling pathway and impaired fertility.

Geography shapes the genomics and antimicrobial resistance of Salmonella enterica Serovar Enteritidis isolated from humans.

Multidrug-resistant (MDR) Salmonella has been a long-standing challenge in public health and food safety. The prevalence of MDR S. Enteritidis, especially isolated from humans, in China is significantly higher than those from the U.S. and other countries. A dataset of 197 S. Enteritidis genomes, including 16 sequenced clinical isolates from China and 181 downloaded genomes of human isolates from the U.S., Europe, and Africa, was analyzed for genomic diversity, virulence potential, and antimicrobial resistance (AMR). Phylogenomic analyses identified four major well-supported clades (I-IV). While AMR genotype in the majority of isolates in clades I and IV displayed as pan-susceptible, 81.8% (9/11) and 22.4% (13/58) of isolates in clades III and II were MDR, respectively. It is noted that 77% (10/13) of MDR isolates in clade II were from China. The most common antimicrobial resistance genes (ARGs) carried by the Chinese isolates were aph(3')-IIa, blaCTX-M-55, and blaTEM-1B, whereas blaTEM-1B, sul1, sul2, drfA7, aph(3")-Ib/strA, and aph(6)-Id/strB were most often identified in those from Africa (clade III). Among the 14 plasmid types identified, IncX1 and IncFII(pHN7A8) were found exclusively in the Chinese MDR isolates, while IncQ1 was highly associated with the African MDR isolates. The spvRABCD virulence operon was present in 94.9% (187/197) of isolates tested and was highly associated with both the IncF (IncFII and IncFIB) plasmids. In addition, phylogenetic differences in distribution of Salmonella pathogenicity islands (SPIs), prophages and other accessory genes were also noted. Taken together, these findings provide new insights into the molecular mechanisms underpinning diversification of MDR S. Enteritidis.

Host defense against the infection of Klebsiella pneumoniae: New strategy to kill the bacterium in the era of antibiotics?

Klebsiella pneumoniae (K. pneumoniae) is a typical gram-negative iatrogenic bacterium that often causes bacteremia, pneumonia and urinary tract infection particularly among those with low immunity. Although antibiotics is the cornerstone of anti-infections, the clinical efficacy of ß-lactamase and carbapenems drugs has been weakened due to the emergence of drug-resistant K. pneumoniae. Recent studies have demonstrated that host defense plays a critical role in killing K. pneumoniae. Here, we summarize our current understanding of host immunity mechanisms against K. pneumoniae, including mechanical barrier, innate immune cells, cellular immunity and humoral immunity, providing a theoretical basis and the new strategy for the clinical treatment of K. pneumoniae through improving host immunity.

Whole genome sequencing analyses revealed that Salmonella enterica serovar Dublin strains from Brazil belonged to two predominant clades.

Salmonella Dublin is a cattle-associated serovar sporadically causing disease in humans. S. Dublin strains isolated in Brazil and in other countries were analyzed to determine their phylogenetic relationships, the presence of genes, plasmids, genomic regions related to virulence and antimicrobial resistance genes repertoire, using WGS analyses. Illumina was used to sequence the genome of 112 S. Dublin strains isolated in Brazil from humans (n = 82) and animals (n = 30) between 1983 and 2016. Furthermore, 87 strains from other countries were analyzed. WGSNP analysis revealed three different clades, in which the strains from Brazil belonged to two clades, A and C. Most of the genes and genomic regions searched varied among the strains studied. The siderophore genes iroB and iroC were exclusively found in strains from Brazil and pegD gene, related to fimbrial adherence determinants, were positive in 124 strains from clades A and B but absent in all the strains from clade C (n = 71). Eleven plasmid replicons were found in the strains from Brazil, and nine were exclusively found in strains from other countries. The antimicrobial resistance genes mdsA and mdsB, that encode an efflux pump, were found in all the strains studied. The strains from Brazil carried other resistance genes, such as tet(A) (n = 11), tet(B) (n = 4) and tet(C) (n = 4), blaTEM-1 (n = 4), catA1 (n = 1), aadA1 (n = 1), and sul1 (n = 1). In conclusion, S. Dublin strains isolated in Brazil presented some few unique genes not found in strains from other countries and were allocated into two distinct clades with strains of human and animal origin epidemiologically related. This fact stresses the zoonotic potential of S. Dublin circulating in Brazil for more than 30 years.

SRT1720 plays a role in oxidative stress and the senescence of human trophoblast HTR8/SVneo cells induced by D-galactose through the SIRT1/FOXO3a/ROS signalling pathway.

D-galactose (D-gal) is a reducing sugar widely distributed in food. In a pregnant animal model exposed to D-gal, D-gal was found to have toxic effects on both the mother and foetus through oxidative stress. However, little is known about the effect of D-gal exposure on the placenta and its underlying mechanism. In this study, we evaluated the effects of D-gal on HTR8/SVneo cells and the mechanisms in vitro. In the present study, the activity of HTR8/SVneo human trophoblasts decreased in a time- and concentration-dependent manner after exposure to D-gal. D-gal resulted in premature senescence of HTR8/SVneo cells, as confirmed by assessing ß-galactosidase (SA-ß-gal) activity and the expression of senescence-related factor p21. We also verified the damage of oxidative stress induced by D-gal by measuring the expression of reactive oxygen species (ROS), sirtuin 1 (SIRT1) and forkhead box O (FOXO) 3a. SRT1720, as a SIRT1 activator, mitigated D-gal-induced oxidative stress and senescence by upregulating SIRT1 and FOXO3a expression and reducing ROS production. Our data suggest that D-gal may induce HTR8/SVneo premature ageing through the SIRT1/FOXO3a/ROS signalling pathway mediated by oxidative stress and that SIRT1 protects cells from this damage.

Evaluation of Virulence Determinants Using Whole-Genome Sequencing and Phenotypic Biofilm Analysis of Outbreak-Linked Staphylococcus aureus Isolates.

Biofilms are a frequent cause of food contamination of potentially pathogenic bacteria, such as Staphylococcus aureus. Given its vast role in human disease, the possible impact of biofilm-producing S. aureus isolates in a food processing environment is evident. Sixty-nine S. aureus isolates collected from one firm following multiple staphylococcal food poisoning outbreak investigations were utilized for this analysis. Strain evaluations were performed to establish virulence determinants and the evolutionary relationships using data generated by shotgun whole-genome sequencing (WGS), along with end point polymerase chain reaction (PCR) and in vitro phenotypic assessments. S. aureus isolates were grouped into six well-supported clades in the phylogenetic tree, with the relationships within the clades indicating a strong degree of clonal structure. Our analysis identified four major sequence types 47.8% ST1, 31.9% ST45, 7.2% ST5, and 7.2% ST30 and two major spa types 47.8% t127 and 29.0% t3783. Extrapolated staphylococcal enterotoxin (SE) analysis found that all isolates were positive for at least 1 of the 23 SEs and/or SE-like toxin genes. Enterotoxigenic assessments found that 93% of the isolates expressed a classical SE(A-E). SE gene concurrence was observed at 96.2%, based on PCR and WGS results. In total, 46 gene targets were distinguished. This included genes that encode for adhesion and biofilm synthesis such as clfA, clfB, bbp, ebpS, ica, bap and agr. Our evaluation found agr group III to be the most prevalent at 55%, followed by 35% for agr group I. All isolates harbored the complete intercellular adhesion operon that is recognized to contain genes responsible for the adhesion step of biofilm formation by encoding proteins involved in the syntheses of the biofilm matrix. Phenotypic characterization of biofilm formation was evaluated three times, with each test completed in triplicate and accomplished utilizing the microtiter plate method and Congo red agar (CRA). The microtiter plate results indicated moderate to high biofilm formation for 96% of the isolates, with 4% exhibiting weak to no biofilm development. CRA results yielded all positive to intermediate results. The potential to inadvertently transfer pathogenic bacteria from the environment into food products creates challenges to any firm and may result in adulterated food.

Draft Genome Sequences of 62 Staphylococcus aureus Isolates Associated with Four Foodborne Outbreaks in the United States.

Staphylococcus aureus bacteria are ranked among the top five foodborne pathogens in the United States. Here, we report the draft genome sequences of 62 S. aureus isolates that originated from the manufacturing environment of an Illinois bakery and were associated with outbreaks between 2010 and 2011 in the United States.

Experimental study of nitrobenzene degradation in water by strong ionization dielectric barrier discharge.

Nitrobenzene (NB) is toxic and carcinogenic aromatic compound widely used in several industries which is ultimately found in their effluents. In this work, dielectric barrier discharge (DBD) reactor was employed for the degradation of nitrobenzene in aqueous solution. Active species like O3 and •OH produced by DBD reactor were mixed with water which degraded the NB. The results indicated that the lower NB concentrations slightly acidic conditions and high voltage ranges showed the optimum efficiencies. Moreover, the impacts of active species inhibitors isopropyl alcohol (IPA), tert-butanol (TBA), inorganic ions for instance sulfates ( S O 4 2 - ), bicarbonates ( H C O 3 - ), nitrates ( N O 3 - ), carbonates ( C O 3 2 - ) and chlorides (Cl-) on the degradation of NB were examined. This analysis showed that the hydroxyl radical was captured by the addition of these inhibitors and resulted in the decrease in efficiencies. Byproducts produced during the degradation of nitrobenzene were assessed by analytical techniques of high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), UV-visible spectroscopy and total organic carbon (TOC) analysis. Main intermediate products were nitrophenols and low molecular weight organic acids including oxalic acid and acetic acid that were eventually mineralized to CO2 and H2O. The dielectric barrier discharge technology was found productive for the degradation of nitroaromatic compounds.

Effect of Time, Temperature, and Transport Media on the Recovery of Listeria monocytogenes from Environmental Swabs.

ABSTRACT: Environmental monitoring for Listeria monocytogenes in food processing environments is key for ensuring the safety of ready-to-eat foods. For sampling, swabs are often hydrated with a wetting or transport medium that may contain neutralizers and other ingredients. After swabbing the environment, the swabs may then be transported or shipped cold to an off-site laboratory for testing, ideally within 48 h. Extended shipping times may subject the pathogen to increased temperatures in the presence of the wetting medium, organics, and other chemicals from the processing facility that could confound detection. This study evaluated growth and detection of L. monocytogenes on stainless steel exposed to either buffer or sodium hypochlorite before drying. Swabs were rehydrated with Butterfield's phosphate buffer, neutralizing buffer, Letheen broth, or Dey-Engley neutralizing broth before swabbing. Swabs were stored in the presence of no added food, cheese whey, or ice cream under both optimal (4°C) and suboptimal (15°C) temperatures for up to 72 h. Overall, there was no growth of L. monocytogenes at 4°C through 72 h of storage, although enrichment from these swabs was dependent on the presence and type of food matrix. Pathogen growth during storage at 15°C was more variable and depended on both the food matrix and transport media used, with Dey-Engley and Letheen broths allowing for the highest population increases. Overall, more enrichments resulting in L. monocytogenes detections were observed when using Letheen broth and neutralizing buffer than Dey-Engley broth, which resulted in fewer detections at 15°C. Logistic regression and Cochran-Mantel-Haenszel analyses determined that storage temperature, transport media, and food matrix all significantly affected detection of L. monocytogenes, whereas storage time did not have a clear effect on recovery from swabs.

Detection of gluten in a pilot-scale barley-based beer produced with and without a prolyl endopeptidase enzyme.

Immunochemical and mass spectrometric methods were used to examine the gluten composition of a gluten-reduced beer produced by brewing with barley malt in the presence of prolyl endopeptidase (PEP) and a final filtration treatment with diatomaceous earth and perlite. The competitive ELISA is generally considered appropriate for the analysis of hydrolysed gluten, but it is not considered a scientifically valid method for the quantification of gluten in fermented or hydrolysed foods due to the lack of an appropriate reference standard. As no single analytical method can capture the spectrum of gluten-derived products in beer, a comprehensive approach was employed to analyse the intact and hydrolysed fractions of gluten with complementary methods. The combination of PEP addition and diatomaceous earth/perlite filtration was more effective at reducing the concentration of detectable gluten than each of the treatments alone. However, gluten proteins and/or polypeptides were observed in filtered, PEP-treated beers using sandwich ELISA methods, western blot, and bottom-up mass spectrometry. In addition, mass spectrometry results showed that the number of hydrolysed gluten peptides was almost unaffected by the filtration process. Gluten peptides that contained potentially immunopathogenic sequences were identified in the filtered PEP-containing beers by MS. Variability in gluten composition was observed between three replicate pilot-scale productions, suggesting that the gluten profile in beer could differ from batch to batch. As there is uncertainty in the detection and quantification of gluten in hydrolysed and fermented foods, characterisation of hydrolysed gluten by complementary analytical methodologies is recommended.

Comparison of TEMPO® BC with Spiral Plating Methods for the Enumeration of Bacillus cereus in Cosmetic Products Either Naturally Preserved or Preserved with Phenoxyethanol.

Background: The U.S. Food and Drug Administration's (FDA) Bacteriological Analytical Manual (BAM) uses Bacillus cereus rapid agar (BACARA) and Mannitol-yolk-polymyxin (MYP) agar for the enumeration of the members of B. cereus group. Objective: The automated TEMPO Most Probable Number system was compared with the FDA BAM method for the detection of B. cereus group members in cosmetic products. Methods: We inoculated a range of cosmetic products with pure B. cereus spore suspensions (density = 0.5 McFarland) at high (6 log CFU/mL), medium (5 log CFU/mL), and low (4 log CFU/mL) levels. Test portions were aged for 72 h. Five replicates per sample were analyzed; uninoculated test portions served as controls. We also evaluated whether TEMPO BC erroneously detected non-B. cereus or other adulterant organisms. Results: No significant differences (P > 0.05) were found among the TEMPO BC and the BAM spiral plating methods. Correlations between TEMPO BC - BACARA and TEMPO BC - MYP were 0.895 and 0.893 for powder type products, 0.834 and 0.846 for cream and oil-based products, and 0.929 and 0.923 for liquid products, respectively. Non-B. cereus strains were not detected by TEMPO BC. Conclusions: The TEMPO BC method can be used for the detection of B. cereus in cosmetic products without preservatives, or those preserved with either phenoxyethanol or other organic substances.

Assessment of Periodontal Biotype in a Young Chinese Population using Different Measurement Methods.

Periodontal biotype is used to describe the morphological characteristics of periodontal tissues and is closely related to periodontal health and prognosis of many dental treatments. This study was undertaken to explore the periodontal biotype distribution in a young Chinese population and to evaluate the accuracy of different methods for gingival thickness (GT) measurement. A total of 372 teeth from 31 periodontally healthy subjects were included. GT was measured simultaneously by probe transparency, transgingival probing and cone-beam computed tomography (CBCT). Some other anatomic parameters, including crown width/crown length ratio, attached gingival width, labial bone thickness and papilla volume were recorded for periodontal biotype classification. As found by probe transparency, the gingivae of 222 teeth (59.68%) were thick, while those of 150 teeth (40.32%) were thin. The mean GT of included subjects was 1.03 ± 0.31 mm as measured by transgingival probing and 1.03 ± 0.24 mm as measured by CBCT. Four groups were identified by cluster analysis. Thick-flap biotype, average-scalloped biotype, average-flap biotype and thin-scalloped biotype comprised 137 teeth (36.83%), 96 teeth (25.81%), 39 teeth (10.48%) and 100 teeth (26.88%), respectively. These results demonstrate that the most common periodontal biotype in this young Chinese population was the thick-flap type with low aesthetic risk.

Molecular and histological characterization of age spots.

Age spots, also called solar lentigines and lentigo senilis, are light brown to black pigmented lesions of various sizes that typically develop in chronically sun-exposed skin. It is well known that age spots are strongly related to chronic sun exposure and are associated with photodamage and an increased risk for skin cancer; however, the mechanisms underlying their development remain poorly understood. We used immunohistochemical analysis and microarray analysis to investigate the processes involved in their formation, focusing on specific markers associated with the functions and proliferation of melanocytes and keratinocytes. A total of 193 genes were differentially expressed in age spots, but melanocyte pigment genes were not among them. The increased expression of keratins 5 and 10, markers of basal and suprabasal keratinocytes, respectively, in age spots suggests that the increased proliferation of basal keratinocytes combined with the decreased turnover of suprabasal keratinocytes leads to the exaggerated formation of rete ridges in lesional epidermis which in turn disrupts the normal processing of melanin upwards from the basal layer. Based on our results, we propose a model for the development of age spots that explains the accumulation of melanin and the development of extensive rete ridges in those hyperpigmented lesions.

Identification of Genes Expressed in Hyperpigmented Skin Using Meta-Analysis of Microarray Data Sets.

More than 375 genes have been identified that are involved in regulating skin pigmentation and these act during development, survival, differentiation, and/or responses of melanocytes to the environment. Many of these genes have been cloned, and disruptions of their functions are associated with various pigmentary diseases; however, many remain to be identified. We have performed a series of microarray analyses of hyperpigmented compared with less pigmented skin to identify genes responsible for these differences. The rationale and goal for this study was to perform a meta-analysis on these microarray databases to identify genes that may be significantly involved in regulating skin phenotype either directly or indirectly that might not have been identified due to subtle differences by any of these individual studies alone. The meta-analysis demonstrates that 1,271 probes representing 921 genes are differentially expressed at significant levels in the 5 microarray data sets compared, providing new insights into the variety of genes involved in determining skin phenotype. Immunohistochemistry was used to validate two of these markers at the protein level (TRIM63 and QPCT), and we discuss the possible functions of these genes in regulating skin physiology.

NUAK2 Amplification Coupled with PTEN Deficiency Promotes Melanoma Development via CDK Activation.

The AMPK-related kinase NUAK2 has been implicated in melanoma growth and survival outcomes, but its therapeutic utility has yet to be confirmed. In this study, we show how its genetic amplification in PTEN-deficient melanomas may rationalize the use of CDK2 inhibitors as a therapeutic strategy. Analysis of array-CGH data revealed that PTEN deficiency is coupled tightly with genomic amplification encompassing the NUAK2 locus, a finding strengthened by immunohistochemical evidence that phospho-Akt overexpression was correlated with NUAK2 expression in clinical specimens of acral melanoma. Functional studies in melanoma cells showed that inactivation of the PI3K pathway upregulated p21 expression and reduced the number of cells in S phase. NUAK2 silencing and inactivation of the PI3K pathway efficiently controlled CDK2 expression, whereas CDK2 inactivation specifically abrogated the growth of NUAK2-amplified and PTEN-deficient melanoma cells. Immunohistochemical analyses confirmed an association of CDK2 expression with NUAK2 amplification and p-Akt expression in melanomas. Finally, pharmacologic inhibition of CDK2 was sufficient to suppress the growth of NUAK2-amplified and PTEN-deficient melanoma cells in vitro and in vivo. Overall, our results show how CDK2 blockade may offer a promising therapy for genetically defined melanomas, where NUAK2 is amplified and PTEN is deleted.

Photobiological implications of melanin photoprotection after UVB-induced tanning of human skin but not UVA-induced tanning.

Repetitive suberythemal UVA and/or UVB exposures were used to generate comparable UV-induced tans in human skin over the course of 2 weeks. To evaluate the potential photoprotective values of those UVA- and/or UVB- induced tans and to avoid the confounding issue of residual UV-induced DNA damage, we waited 1 week before challenging those areas with a 1.5 MED of UVA+UVB after which we measure DNA damage. The results show that the type of UV used to induce skin pigmentation affects the redistribution of melanin in the skin and/or de novo melanin synthesis. The UVA-induced tans failed to even provide a minimal SPF of 1.5, which suggests that producing a tan with UVA-rich sunlamps prior to a holiday or vacation is completely counterproductive.

UV exposure modulates hemidesmosome plasticity, contributing to long-term pigmentation in human skin.

Human skin colour, ie pigmentation, differs widely among individuals, as do their responses to various types of ultraviolet radiation (UV) and their risks of skin cancer. In some individuals, UV-induced pigmentation persists for months to years in a phenomenon termed long-lasting pigmentation (LLP). It is unclear whether LLP is an indicator of potential risk for skin cancer. LLP seems to have similar features to other forms of hyperpigmentation, eg solar lentigines or age spots, which are clinical markers of photodamage and risk factors for precancerous lesions. To investigate what UV-induced molecular changes may persist in individuals with LLP, clinical specimens from non-sunburn-inducing repeated UV exposures (UVA, UVB or UVA + UVB) at 4 months post-exposure (short-term LLP) were evaluated by microarray analysis and dataset mining. Validated targets were further evaluated in clinical specimens from six healthy individuals (three LLP+ and three LLP-) followed for more than 9 months (long-term LLP) who initially received a single sunburn-inducing UVA + UVB exposure. The results support a UV-induced hyperpigmentation model in which basal keratinocytes have an impaired ability to remove melanin that leads to a compensatory mechanism by neighbouring keratinocytes with increased proliferative capacity to maintain skin homeostasis. The attenuated expression of SOX7 and other hemidesmosomal components (integrin α6ß4 and plectin) leads to increased melanosome uptake by keratinocytes and points to a spatial regulation within the epidermis. The reduced density of hemidesmosomes provides supporting evidence for plasticity at the epidermal-dermal junction. Altered hemidesmosome plasticity, and the sustained nature of LLP, may be mediated by the role of SOX7 in basal keratinocytes. The long-term sustained subtle changes detected are modest, but sufficient to create dramatic visual differences in skin colour. These results suggest that the hyperpigmentation phenomenon leading to increased interdigitation develops in order to maintain normal skin homeostasis in individuals with LLP.

A Functional Data Analysis Approach for Circadian Patterns of Activity of Teenage Girls.

BACKGROUND: Longitudinal or time-dependent activity data are useful to characterize the circadian activity patterns and to identify physical activity differences among multiple samples. Statistical methods designed to analyze multiple activity sample data are desired, and related software is needed to perform data analysis. METHODS: This paper introduces a functional data analysis (fda) approach to perform a functional analysis of variance (fANOVA) for longitudinal circadian activity count data and to investigate the association of covariates such as weight or body mass index (BMI) on physical activity. For multiple age group adolescent school girls, the fANOVA approach is developed to study and to characterize activity patterns. The fANOVA is applied to analyze the physical activity data of three grade adolescent girls (i.e., grades 10, 11, and 12) from the NEXT Generation Health Study 2009-2013. To test if there are activity differences among girls of the three grades, a functional version of the univariate F-statistic is used to analyze the data. To investigate if there is a longitudinal (or time-dependent activity count) difference between two samples, functional t-tests are utilized to test: (1) activity differences between grade pairs; (2) activity differences between low-BMI girls and high-BMI girls of the NEXT study. RESULTS: Statistically significant differences existed among the physical activity patterns for adolescent school girls in different grades. Girls in grade 10 tended to be less active than girls in grades 11 & 12 between 5:30 and 9:30. Significant differences in physical activity were detected between low-BMI and high-BMI groups from 8:00 to 11:30 for grade 10 girls, and low-BMI group girls in grade 10 tended to be more active. CONCLUSIONS: The fda approach is useful in characterizing time-dependent patterns of actigraphy data. For two-sample data defined by weight or BMI values, fda can identify differences between the two time-dependent samples of activity data. Similarly, fda can identify differences among multiple physical activity time-dependent datasets. These analyses can be performed readily using the fda R program.