Biodegradation study of poly(hydroxybutyrate-co-hydroxyvalerate)/halloysite/oregano essential oil compositions in simulated soil conditions.

The aim of this work was to evaluate the influence of halloysite clay nanoparticles - unmodified (Hal) and organically modified (mHal) - and oregano essential oil (OEO), used as an antimicrobial agent in active packaging, on the biodegradation behavior of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) films. Five samples were prepared by melt mixing using 3 wt% clay, and 8 wt% and 10.4 wt% OEO. PHBV compositions containing OEO presented the highest rate of biodegradation, achieving 46% of mass loss after aging for 12 weeks in simulated soil. The addition of clay nanoparticles reduced the polymer's biodegradation to 32%. The compositions containing OEO showed a rough and layered surface with visible cracks, indicating degradation occurring through layer-by-layer erosion from the surface. This degradation was confirmed by the chemical changes on the surface of all samples, with a slight decrease in molar masses. The composition containing 8 wt% OEO presented an increase in the crystallization degree as a result of the preferential consumption of amorphous phase, whereas for the compositions containing clay nanoparticles, both crystalline and amorphous regions were degraded at similar rates. Therefore, the combination of additives allows the biodegradation process of PHBV to be controlled for use in the production of active packaging.

The More You Know, the Less You Stress: Menstrual Health Literacy in Schools Reduces Menstruation-Related Stress and Increases Self-Efficacy for Very Young Adolescent Girls in Mexico.

Improving the menstrual health literacy of girls and boys is a key strategy within a holistic framework of Save the Children's school health and comprehensive sexuality education programming. As menstrual health is an emerging area of study and programming, Save the Children continues to learn and adjust its interventions using program evaluations and rigorous monitoring. This paper will examine program-monitoring data from three cohorts, representing 47 public schools in Mexico City, Puebla, and Mérida, Mexico. The study focuses on female students in 5th and 6th grade who participated in We See Equal, a school-based program centered on gender equality and puberty education, between September 2018 and December 2019. This study used a cross-sectional quantitative cohort approach to document changes in girls' experiences and perceptions around managing menstruation in school. The analysis compares girls' knowledge and experiences before and after participation in We See Equal to understand how knowledge changes over the program and how those changes may contribute to menstruation-related school engagement, stress, and self-efficacy (MENSES) outcomes. Multivariate regression models explored relationships between MENSES outcomes, knowledge and socioeconomic status (SES). Overall, results show that the more knowledge girls acquired, the higher their self-efficacy score and the lower their stress score, however, certain MHH knowledge was more predictive of MENSES outcomes and varied by SES. Among girls from lower SES, we observed significant relationships between knowing what their period was prior to menarche and the three MENSES outcomes. Decreases in menstruation-related stress were driven by items related to the practical knowledge of how to dispose of sanitary pads and reduced feelings of nervousness on days they had their period at school. Increases in self-efficacy were primarily driven by girls' confidence in their ability to track their period from month to month, feelings that they could still do well on an exam if they had their period at school, and security that they could ask a friend to lend them a pad if they needed one. Implications for future menstrual health literacy programming and targeting populations for menstrual health education, as well as priorities for future research will be discussed.

Data on SVCT2 transporter expression and localization in cancer cell lines and tissues.

The data presented in this article are related to the research paper entitled "Increased expression of mitochondrial sodium-coupled ascorbic acid transporter-2 (mitSVCT2) as a central feature in breast cancer", available in Free Radical Biology and Medicine Journal [1]. In this article, we examined the SVCT2 transporter expression in various breast cancer cell lines using RT-PCR and Western blot assays. In addition, we analyzed the subcellular localization of SVCT2 by immunofluorescence colocalization assays and cellular fractionation experiments. Finally, an analysis of different cancer tissue microarrays immunostained for SVCT2 and imaged by The Human Protein Atlas (https://www.proteinatlas.org) is presented.

Increased expression of mitochondrial sodium-coupled ascorbic acid transporter-2 (mitSVCT2) as a central feature in breast cancer.

The potential role of vitamin C in cancer prevention and treatment remains controversial. While normal human cells obtain vitamin C as ascorbic acid, the prevalent form of vitamin C in vivo, the uptake mechanisms by which cancer cells acquire vitamin C has remained unclear. The aim of this study is to characterize how breast cancer cells acquire vitamin C. For this, we determined the expression of vitamin C transporters in normal and breast cancer tissue samples, and in ZR-75, MCF-7, MDA-231 and MDA-468 breast cancer cell lines. At the same time, reduced (AA) and oxidized (DHA) forms of vitamin C uptake experiments were performed in all cell lines. We show here that human breast cancer tissues differentially express a form of SVCT2 transporter, that is systematically absent in normal breast tissues and it is increased in breast tumors. In fact, estrogen receptor negative breast cancer tissue, exhibit the most elevated SVCT2 expression levels. Despite this, our analysis in breast cancer cell lines showed that these cells are not able to uptake ascorbic acid and depend on glucose transporter for the acquisition of vitamin C by a bystander effect. This is consistent with our observations that this form of SVCT2 is completely absent from the plasma membrane and is overexpressed in mitochondria of breast cancer cells, where it mediates ascorbic acid transport. This work shows that breast cancer cells acquire vitamin C in its oxidized form and are capable of accumulated high concentrations of the reduced form. Augmented expression of an SVCT2 mitochondrial form appears to be a common hallmark across all human cancers and might have implications in cancer cells survival capacity against pro-oxidant environments.

Sustained blockade of ascorbic acid transport associated with marked SVCT1 loss in rat hepatocytes containing increased ascorbic acid levels after partial hepatectomy.

The liver has an extraordinary regenerative capacity in response to partial hepatectomy (PHx), which develops with neither tissue inflammation response nor alterations in the whole organism. This process is highly coordinated and it has been associated with changes in glutathione (GSH) metabolism. However, there are no reports indicating ascorbic acid (AA) levels after partial hepatectomy. AA and GSH act integrally as an antioxidant system that protects cells and tissues from oxidative damage and imbalance observed in a variety of diseases that affect the liver. Although rat hepatocytes are able to synthesize AA and GSH, which are the providers of AA for the whole organism, they also acquire AA from extracellular sources through the sodium-coupled ascorbic acid transporter-1 (SVCT1). Here, we show that hepatocytes from rat livers subjected to PHx increase their GSH and AA levels from 1 to 7 days post hepatectomy, whose peaks precede the peak in cell proliferation observed at 3 days post-hepatectomy. The increase in both antioxidants was associated with higher expression of the enzymes involved in their synthesis, such as the modifier subunit of enzyme glutamine cysteine ligase (GCLM), glutathione synthetase (GS), gulonolactonase (GLN) and gulonolactone oxidase (GULO). Importantly, rat hepatocytes, that normally exhibit kinetic evidence indicating only SVCT1-mediated transport of AA, lost more than 90% of their capacity to transport it at day 1 after PHx without evidence of recovery at day 7. This observation was in agreement with loss of SVCT1 protein expression, which was undetectable in hepatocytes as early as 2h after PHx, with partial recovery at day 7, when the regenerated liver weight returns to normal. We conclude that after PHx, rat hepatocytes enhance their antioxidant capacity by increasing GSH and AA levels prior to the proliferative peak. GSH and AA are increased by de novo synthesis, however paradoxically hepatocytes from rat subjected to PHx also suppress their capacity to acquire AA from extracellular sources through SVCT1.

Essential role of intracellular glutathione in controlling ascorbic acid transporter expression and function in rat hepatocytes and hepatoma cells.

Although there is in vivo evidence suggesting a role for glutathione in the metabolism and tissue distribution of vitamin C, no connection with the vitamin C transport systems has been reported. We show here that disruption of glutathione metabolism with buthionine-(S,R)-sulfoximine (BSO) produced a sustained blockade of ascorbic acid transport in rat hepatocytes and rat hepatoma cells. Rat hepatocytes expressed the Na(+)-coupled ascorbic acid transporter-1 (SVCT1), while hepatoma cells expressed the transporters SVCT1 and SVCT2. BSO-treated rat hepatoma cells showed a two order of magnitude decrease in SVCT1 and SVCT2 mRNA levels, undetectable SVCT1 and SVCT2 protein expression, and lacked the capacity to transport ascorbic acid, effects that were fully reversible on glutathione repletion. Interestingly, although SVCT1 mRNA levels remained unchanged in rat hepatocytes made glutathione deficient by in vivo BSO treatment, SVCT1 protein was absent from the plasma membrane and the cells lacked the capacity to transport ascorbic acid. The specificity of the BSO treatment was indicated by the finding that transport of oxidized vitamin C (dehydroascorbic acid) and glucose transporter expression were unaffected by BSO treatment. Moreover, glutathione depletion failed to affect ascorbic acid transport, and SVCT1 and SVCT2 expression in human hepatoma cells. Therefore, our data indicate an essential role for glutathione in controlling vitamin C metabolism in rat hepatocytes and rat hepatoma cells, two cell types capable of synthesizing ascorbic acid, by regulating the expression and subcellular localization of the transporters involved in the acquisition of ascorbic acid from extracellular sources, an effect not observed in human cells incapable of synthesizing ascorbic acid.

Who and why? HIV-testing refusal during pregnancy: implication for pediatric HIV epidemic disparity.

To identify characteristics of pregnant women who refuse HIV testing and determine predictive factors and the reasons for refusal, we conducted face-to-face interviews of pregnant women at prenatal clinics of public and private hospitals. We found 8% (n=65) of 826 pregnant women interviewed refused HIV testing. In bivariate analysis, foreign-born pregnant women residing in Los Angeles County were twice more likely to refuse HIV testing than U.S.-born pregnant women (odds ratio [OR] = 1.97, 95% confidence interval [CI] 1.11-3.49, p <.05). In a multivariate stepwise logistic regression model analysis, variables that were independent predictors of HIV testing refusal during pregnancy were being foreign-born (OR = 2.11, 95% CI 1.07-4.38), not receiving general information about HIV (OR = 7.48, 95% CI 1.86-30.01), and not receiving specific information about HIV and pregnancy (OR = 3.54, 95% CI 1.91-6.57). The most common reasons for testing refusal were being in a monogamous relationship for foreign-born women (41%) and already being tested for U.S.-born women (65%).