Aspartame, a ‘first generation sweetener’, is widely used in a variety of foods, beverages, and medicine. The FDA has determined the acceptable daily intake (ADI) value of aspartame to be 50 mg/kg of body weight/day, while the JECFA (Joint FAO/WHO Expert Committee on Food Additives) has set this value at 40 mg/kg of body weight/day. Safety issues have been raised about aspartame due to its metabolites, specifically toxicity from methanol and/or its systemic metabolites formaldehyde and formic acid. The immune system is now recognized as a target organ for many xenobiotics, such as drugs and chemicals, which are able to trigger unwanted apoptosis or to alter the regulation of apoptosis. Our previous studies has shown that oral administration of aspartame (40 mg/kg.bw/day) or its metabolites for 90 days increased oxidative stress in immune organs of Wistar albino rats. In this present study, we aimed to clarify whether aspartame consumption over a longer period (90-days) has any effect on the expression of hsp70, bcl-2 and bax at both mRNA transcript and protein expression levels in immune organs. We observed that oral administration of aspartame for 90 days did not cause any apparent DNA fragmentation in immune organs of aspartame treated animals; however, there was a significant increase in hsp70 expression, apart from significant alteration in bcl-2 and bax at both mRNA transcript and protein expression level in the immune organs of aspartame treated animals compared to controls. Hence, the results indicated that hsp70 levels increased in response to oxidative injury induced by aspartame metabolites; however, these metabolites did not induce apoptosis in the immune organs. Furthermore, detailed analyses are needed to elucidate the precise molecular mechanisms involved in these changes.
Epinephrine is often used for the treatment of patients with heart failure, low cardiac output and cardiac arrest. It can acutely improve hemodynamic parameters; however, it does not seem to improve longer term clinical outcomes. Therefore, we hypothesized that epinephrine may induce unfavorable changes in gene expression of cardiomyocyte. Thus, we investigated effects of epinephrine exposure on the mediation or modulation of gene expression of cultured cardiomyocytes at a genome-wide scale. Our investigation revealed that exposure of cardiomyocytes to epinephrine in an in vitro environment can up-regulate the expression of angiopoietin-2 gene (+2.1 times), and down-regulate the gene expression of neuregulin 1 (−3.7 times), plasminogen activator inhibitor-1 (−2.4 times) and SPARC-related modular calcium-binding protein-2 (−4.5 times). These changes suggest that epinephrine exposure may induce inhibition of angiogenesis-related gene expressions in cultured rat cardiomyocytes. The precise clinical significance of these changes in gene expression, which was induced by epinephrine exposure, warrants further experimental and clinical investigations.
Infections are identified as the most common preventable cause of death in pediatric oncology patients. Assessing and stratifying risk of infections are essential to prevent infection in these patients. To date, no tool can fulfill this demand in China. This study aimed to develop a nursing work-based and Chinese-specific tool for pediatric nurses to assess risk of infection in oncology patients. This research was a modified Delphi study. Based on a literature review, a 37-item questionnaire rating on a 0–5 scale was developed. Twenty-four experts from 8 hospitals in 6 provinces of China were consulted for three rounds. Consensus for each item in the first round was defined as: the rating mean was>3 and the coefficient of variation (CV) was<0.5. Consensus for each item in the second round was defined as CV<0.3. Consensus among experts was defined as: P value of Kendall's coefficient of concordance (W)<0.05. After three rounds of consultation, a two-part tool was developed: the Immune Status Scale (ISS) and the Checklist of Risk Factors of Infection (CRFI). There were 5 items in the ISS and 14 in the CRFI. Based on the ISS score, nurses could stratify children into the low-risk and high-risk groups. For high-risk children, nurses should screen risk factors of infection every day by the CRFI, and twice weekly for low-risk children. Further study is needed to verify this tool's efficacy.
Endocrine therapy using estrogen receptor-α (ER-α) antagonists for attenuating horm2one-driven cell proliferation is a major treatment modality for breast cancers. To exploit any DNA repair deficiencies associated with endocrine therapy, we investigated the functional and physical interactions of ER-α with O6-methylguanine DNA methyltransferase (MGMT), a unique DNA repair protein that confers tumor resistance to various anticancer alkylating agents. The ER-α -positive breast cancer cell lines (MCF-7, T47D) and ER- negative cell lines (MDAMB-468, MDAMB-231), and established inhibitors of ER-α and MGMT, namely, ICI-182,780 (Faslodex) and O6-benzylguanine, respectively, were used to study MGMT- ER interactions. The MGMT gene promoter was found to harbor one full and two half estrogen-responsive elements (EREs) and two antioxidant-responsive elements (AREs). MGMT expression was upregulated by estrogen, downregulated by tamoxifen in Western blot and promoter-linked reporter assays. Similarly, both transient and stable transfections of Nrf-2 (nuclear factor-erythroid 2-related factor-2) increased the levels of MGMT protein and activity 3 to 4-fold reflecting novel regulatory nodes for this drug-resistance determinant. Of the different ER-α antagonists tested, the pure anti-estrogen fulvestrant was most potent in inhibiting the MGMT activity in a dose, time and ER-α dependent manner, similar to O6-benzylguanine. Interestingly, fulvestrant exposure led to a degradation of both ER-α and MGMT proteins and O6-benzylguanine also induced a specific loss of ER-α and MGMT proteins in MCF-7 and T47D breast cancer cells with similar kinetics. Immunoprecipitation revealed a specific association of ER-α and MGMT proteins in breast cancer cells. Furthermore, silencing of MGMT gene expression triggered a decrease in the levels of both MGMT and ER-α proteins. The involvement of proteasome in the drug-induced degradation of both proteins was also demonstrated. Fulvestrant enhanced the cytotoxicity of MGMT-targeted alkylating agents, namely, temozolomide and BCNU by 3 to 4-fold in ER-α positive cells, but not in ER–negative cells. We conclude that MGMT and ER-α proteins exist as a complex and are co-targeted for ubiquitin-conjugation and subsequent proteasomal degradation. The findings offer a clear rationale for combining alkylating agents with endocrine therapy.
Aspartame, a ‘first generation sweetener’, is widely used in a variety of foods, beverages, and medicine. The FDA has determined the acceptable daily intake (ADI) value of aspartame to be 50 mg/kg of body weight/day, while the JECFA (Joint FAO/WHO Expert Committee on Food Additives) has set this value at 40 mg/kg of body weight/day. Safety issues have been raised about aspartame due to its metabolites, specifically toxicity from methanol and/or its systemic metabolites formaldehyde and formic acid. The immune system is now recognized as a target organ for many xenobiotics, such as drugs and chemicals, which are able to trigger unwanted apoptosis or to alter the regulation of apoptosis. Our previous studies has shown that oral administration of aspartame (40 mg/kg.bw/day) or its metabolites for 90 days increased oxidative stress in immune organs of Wistar albino rats. In this present study, we aimed to clarify whether aspartame consumption over a longer period (90-days) has any effect on the expression of hsp70, bcl-2 and bax at both mRNA transcript and protein expression levels in immune organs. We observed that oral administration of aspartame for 90 days did not cause any apparent DNA fragmentation in immune organs of aspartame treated animals; however, there was a significant increase in hsp70 expression, apart from significant alteration in bcl-2 and bax at both mRNA transcript and protein expression level in the immune organs of aspartame treated animals compared to controls. Hence, the results indicated that hsp70 levels increased in response to oxidative injury induced by aspartame metabolites; however, these metabolites did not induce apoptosis in the immune organs. Furthermore, detailed analyses are needed to elucidate the precise molecular mechanisms involved in these changes.