Vitamin C intake and apoptosis in normal rectal epithelium.

Apoptosis, or programmed cell death, may lower the risk of neoplasia by removing genetically damaged or mutated cells. A high rate of apoptosis has been linked to a reduced risk of colorectal adenomas; therefore, it is important to understand factors that impact apoptosis. Antioxidants (e.g., vitamin C) protect cells from harmful oxidation processes but may interfere with apoptosis by protecting genetically damaged cells from reactive oxygen species-dependent cell death. The objective of this study was to evaluate the association between vitamin C intake and apoptosis in normal rectal mucosa. Study participants were part of a large, cross-sectional study, the Diet and Health Study III. Participants were recruited from consecutive, consenting patients who underwent colonoscopy at University of North Carolina Hospitals between August 1, 1998 and March 4, 2000. Vitamin C intake, obtained from a food frequency questionnaire, included both dietary sources and vitamin supplements. Apoptosis was measured by morphological evaluation of H&E-stained sections obtained from pinch biopsy samples of normal rectal mucosa in consenting participants (n = 503). The relationship between vitamin C and apoptosis varied by adenoma status. Among individuals with adenomas, there was an inverse linear association between apoptosis and total vitamin C intake. Similarly, individuals with adenomas in the highest quintile of total vitamin C intake were substantially less likely than those in the lowest quintile to have increased colonic apoptosis (odds ratio, 0.05; 95% confidence interval, 0.01-0.46). Vitamin C was not significantly associated with apoptosis in adenoma-free patients. High vitamin C intake was associated with reduced colorectal apoptosis among individuals with adenomas in this study population. Given that high apoptosis may lower colorectal cancer risk, vitamin C supplements may be contraindicated for patients with a history of adenomas.     

Effects of bromelain on motor responses following intra-medial forebrain bundle 6-OHDA injection in rat model of parkinsonism

Metabolic Brain Disease - Parkinson’s disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. The conventional therapeutic...     

A syndemic of psychosocial health problems is associated with increased HIV sexual risk among Nigerian gay,bisexual, and other men who have sex with men (GBMSM)

ABSTRACT

Nigerian gay, bisexual and other men who have sex with men (GBMSM) experience negative psychosocial health problems, which may increase their risk for HIV infection. Few studies have explored the syndemic effect of co-occurring psychosocial health problems on HIV sexual risk among Nigerian GBMSM. We investigated the co-occurrence of syndemic psychosocial health problems and their synergistic effect on HIV risk behaviors. We assessed depressive symptoms, post-traumatic stress disorder, alcohol dependence, tobacco use, and hard-drug use. The outcome variables were the number of male sexual partners and consistent condom use. In a multivariable model, experiencing 4 or more psychosocial health problems – compared to experience none or one psychosocial health problem – was significantly associated with increasing number of male sexual partners. We found no statistically significant association between the number of syndemic psychosocial health problems and consistent condom use. Our study findings provides evidence of a synergistic relationship between negative psychosocial health factors and HIV sexual risk behavior. These findings underscore the importance of developing HIV prevention programming aimed at reducing HIV transmission risk that incorporate substance use and mental health treatments, in order to improve the overall health and quality of life for Nigerian GBMSM.     

Effects of the novel catalyst Ni–S2O82−–K2O/TiO2 on efficient lignin depolymerization

To improve the utilization of lignin, much effort has been devoted to lignin depolymerization with the aim to decrease waste and enhance profitability. Here, a dual property (acid and base) catalyst, namely S₂O₈²⁻–K₂O/TiO₂, was carefully researched. Upon loading S₂O₈²⁻ and K₂O onto TiO₂, acid and base sites emerged, and S₂O₈²⁻ and K₂O mutually enhanced the acid and base strengths of the catalyst enormously; this indeed facilitated lignin depolymerization. Under appropriate conditions, the yields of liquid product, petroleum ether soluble (PE-soluble) product and total monomer products were 83.76%, 50.4% and 28.96%, respectively. The constituents of the PE-soluble fraction, which are mainly monomers and dimers, can be used as liquid fuels or additives. In addition, after the catalyst was modified by Ni, better results were obtained. Surprisingly, it was found that the Ni enhanced not only the hydrogenation capacity but also the acidity. The highest high heating value (HHV) of the liquid product (33.6 MJ kg⁻¹) was obtained, and the yield of PE-soluble product increased from 50.4 to 56.4%. The product can be utilized as a fuel additive or be converted to bio-fuel. This catalysis system has significant potential in the conversion of lignin to bio-fuel.

To improve the utilization of lignin, much effort has been devoted to lignin depolymerization with the aim to decrease waste and enhance profitability.     

Isolation and identification of three new chromones from the leaves of Pimenta dioica with cytotoxic,oestrogenic and anti-oestrogenic effects

Context: Pimenta dioica (L.) Merr. (Myrtaceae) is used in Costa Rican traditional medicine for women’s health. Our previous work showed that P. dioica extracts were oestrogenic.

Objectives: This work identifies phytochemicals from P. dioica that are responsible for the plant’s oestrogen-like activities.

Materials and methods: P. dioica leaves were collected in Costa Rica in 2005. Fractions resulting from chromatographic separation of a methanol extract were tested at 50?μg/mL in a competitive oestrogen receptor-binding assay. Active compounds were isolated by HPLC and identified by NMR and MS. Pure compounds were tested at 1?μM in the oestrogen-responsive SEAP reporter gene assay. The effects on cell viability, cytotoxicity and apoptosis were investigated in breast cancer (MCF-7 and SK-BR3) and gastric cancer (AGS and NCI-N87) cell lines using the ApoTox-Glo and Caspase-Glo assays and qPCR.

Results: Quercitrin and three new chromones, including a 2-phenoxychromone, 6,8-di-C-methylcapillarisin (1) were isolated and identified. Compound 1 caused a 6.2-fold increase in SEAP expression at 1?μM (p?2 caused a 6.0-fold increase in SEAP, inhibited the growth of MCF-7, AGS and NCI-N87 cells (IC₅₀ 54.27, 38.13 and 51.22?μg/mL, respectively), and induced apoptosis via caspase 8 and increased the Bax/Bcl-2 mRNA ratio in MCF-7 cells. Compound 3 was anti-oestrogenic in MCF-7 cells.

Discussion and conclusions: Compounds from P. dioica have oestrogenic, anti-oestrogenic and cytotoxic effects that may explain the ethnomedical use of this plant.     

Food Frequency Questionnaires and Overnight Urines Are Valid Indicators of Daidzein and Genistein Intake in U.S. Women Relative to Multiple 24-h Urine Samples

Data regarding convenient, valid methods for measuring U.S. isoflavone intake are limited. We evaluated a soy food questionnaire (SFQ), the Willett food frequency questionnaire (FFQ), and overnight urine samples relative to excretion in 24-h urine samples. We also described intake among women in a high-risk program for breast or ovarian cancer. Between April 2002 and June 2003, 451 women aged 30 to 50 yr with a family history of breast or ovarian cancer completed the SFQ and FFQ. Of them, 27 provided four 24-h and overnight urine specimens. In these women, 24-h sample measures were correlated with SFQ estimates of daidzein (Spearman r = .48) and genistein (r = .54) intake, moderately correlated with the Willett FFQ (daidzein r = .38, genistein r = .33), and strongly correlated with overnight urine excretion (daidzein r = .84, genistein r = 0.93). Among all 451 SFQ respondents, mean (median) daidzein and genistein intakes were 2.8 (0.24) and 3.9 (0.30) mg/day. Primary sources of both were soymilk, soy nuts, and tofu. We conclude that targeted soy food questionnaires, comprehensive FFQs, and multiple overnight urines are all reasonable options for assessing isoflavone intake in epidemiologic studies.     

Local IGFBP-3 mRNA expression,apoptosis and risk of colorectal adenomas

Background  

IGF binding protein-3 (IGFBP-3) regulates the bioavailability of insulin-like growth factors I and II, and has both anti-proliferative and pro-apoptotic properties. Elevated plasma IGFBP-3 has been associated with reduced risk of colorectal cancer (CRC), but the role of tissue IGFBP-3 is not well defined. We evaluated the association between tissue or plasma IGFBP-3 and risk of colorectal adenomas or low apoptosis.