Metabolic effects of bariatric surgery in type 2 diabetic patients with body mass index < 35 kg/m2

AIM

The aim of this meta-analysis is to assess the metabolic effects of bariatric surgery in type 2 diabetes mellitus (T2DM) patients with body mass index (BMI) < 35 kg/m(2) .

METHODS

We performed an electronic literature search of published articles to identify relevant evidence since inception to June 2011. Primary outcome measures were metabolic improvement and resolution diabetes after bariatric surgery. The weighted mean difference (WMD) and its 95% confidence interval (CI) were calculated from the raw data extracted from the original literature. The software Review Manager (version 4.3.1) was applied for meta-analysis.

RESULTS

Thirteen trials involving 357 patients were included in the meta-analysis. The follow-up interval ranged from 6 months to 18 years. According to WMD calculation, bariatric surgery led to 5.18 kg/m(2) of BMI lowering (95% CI, 3.79-6.57, p < 0.00001), 4.8 mmol/l of fasting plasma glucose (FPG) decrement (95% CI, 3.88-5.71 mmol/l, p < 0.00001), 2.59% of HbA1c decreasing (95% CI, 2.12-3.07%, p < 0.00001), 56.67 mg/dl of triglyceride decrement (95% CI 11.53-101.82, p = 0.01) and 48.38 mg/dl of total cholesterol reduction (95% CI 21.08-75.68, p = 0.0005). Moreover, the procedures produced an increased high-density lipoprotein cholesterol by 5.37 mg/dl (95% CI -11.37-0.63, p = 0.08). However, this effect was not statistically significant. Overall, 80.0% of the patients achieved adequate glycaemic control (HbA1c < 7%) without antidiabetic medication. The surgeries produced a low incidence of major complications (3.2%) with no mortality.

CONCLUSIONS

Bariatric surgery is effectual and safe in the treatment of non-severely obese (BMI < 35 kg/m(2) ) T2DM patients. Moreover, the metabolic benefits acquired from the procedures can be long sustained after the surgery.

P5-01-13: High Levels of Nuclear Heat Shock Factor 1 (HSF1) Are Associated with Poor Prognosis in Breast Cancer: Results from the Nurses' Health Study

Purpose: Heat shock factor 1 (HSF1) is the master transcriptional regulator of the cellular response to heat and a wide variety of other stressors. We previously reported that HSF1 promotes the survival and proliferation of malignant cells. At this time, however, the clinical and prognostic significance of HSF1 in cancer is unknown.

Patients and methods: Breast cancer samples from 1,841 participants in the Nurses’ Health Study (NHS) were scored for levels of nuclear HSF1. Associations of HSF1 status with clinical parameters and survival outcomes were investigated by Kaplan-Meier analysis and Cox proportional hazard models. The associations were further delineated by Kaplan-Meier analysis using publicly available mRNA expression data.

Results: Nuclear HSF1 levels were elevated in ∼80% of in situ and invasive breast carcinomas. In invasive carcinomas, HSF1 expression was associated with high histologic grade, larger tumor size, and nodal involvement at diagnosis (P&lt;0.0001). Overall, in multivariate analysis, high-HSF1 levels were associated with increased breast cancer-specific mortality (HR, 1.62; 95% CI, 1.21−2.17). This association was seen in the ER-positive population (HR, 2.10; 95% CI, 1.25−2.47), even in early-stage lymph node negative cases (HR, 1.98; 95% CI, 1.17−3.33). In public expression profiling data, high-HSF1 mRNA levels were also associated with an increase in ER-positive breast cancer-specific mortality.

Conclusions: Increased HSF1 is associated with reduced survival in breast cancer. The findings indicate that HSF1 should be evaluated prospectively as an independent prognostic indicator in ER-positive breast cancer and that HSF1 may provide a useful therapeutic target.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-01-13.

P4-02-12: Plasma Estradiol Levels and Degree of Estrogen Receptor Positivity by Image Analysis in a Large Cohort of Breast Cancer Cases: Results from the Nurses' Health Study

Background

Breast cancer risk is strongly associated with endogenous reproductive hormones. There is also good evidence to suggest that endogenous estradiol levels are more strongly associated with the development of estrogen receptor (ER) positive breast cancers than with ER negative cancers. However, the degree of ER positivity in those cancers that develop is not yet established. Therefore, we sought to evaluate the proportion and intensity of tumor cells demonstrating ER positivity using image analysis in a large cohort of breast cancers for which we also had plasma estradiol levels.

Design: Tissue microarray (TMA) sections of breast cancers from women enrolled in the Nurses’ Health Study were immunostained for ER (1D5, Dako Corporation, Carpinteria, CA). Slides were then scanned using the ScanScope slide scanning system (Aperio Technologies Inc., Vista, CA) and ER staining was assessed for both intensity and percent of nuclei staining positively using a specific algorithm, Nuclear v9, which evaluates nuclear size, intensity, roundness, curvature, compactness, and elongation. Plasma samples were collected prior to the date of diagnosis for all women in the study and estradiol levels were determined by radioimmunoassay following extraction and celite column chromatography.

Result: Image analysis data for ER was available for 691 breast cancers. The mean percent of tumor cell positivity was approximately uniformly distributed, with a mean of 44.5%, (median=41.3%, max=99.6%). The proportion of tumor cells staining for ER from the TMA cores was positively associated with patient age (p&lt;0.0001), and postmenopausal status (p=0.008), while inversely associated with tumor grade (p&lt;0.0001). Among women with image analysis data for ER, plasma estradiol data were also available for 320 postmenopausal women. Estrogen receptor positivity (by proportion or intensity) did not vary according to plasma estradiol levels (p=0.17).

Exercise improved rat metabolism by raising PPAR-α

Based on the importance of exercise and crucial role of liver in metabolism, the aim of this study was to determine whether the expression of peroxisome proliferator-activated receptor (PPAR)-α, γ and adiponectin receptor 2 in OLETF rat liver were altered in conjunction with improved metabolism with exercise training. OLETF rats were randomly assigned to 2 groups: sedentary control group (n=26), and long-term exercise-trained group (n=26). Full data were available on 32 OLETF rats (16 for each group). Adiponectin, glucose, insulin, triglyceride and cholesterol were assessed. Livers were taken to determine the expression of PPAR-α, γ and adiponectin receptor 2. Compared with sedentary control group, fasting glucose (9.38 ± 2.99 mmol/L vs. 7.32 ± 1.76 mmol/L, P<0.05), triglyceride (1.73 ± 0.34 mmol/L vs. 0.89 ± 0.12 mmol/L, P<0.05) and cholesterol (4.41 ± 0.75 mmol/L vs. 2.13 ± 0.32 mmol/L, P<0.05) were substantially reduced after exercise, which significantly correlated with increased PPAR-α (P<0.05) in liver. The expression of PPAR-α upstream and target genes, including hepatocyte nuclear factor-4 (HNF4), carnitine palmitoyl transferase 1 (CPT-1), catalase (CAT) and ATPbinding cassette transporter A1 (ABCA1) also increased significantly. Therefore, our findings suggest that increased PPAR-α expression in OLETF rats liver is a contributory factor to the exercise-related improvements in whole-body metabolism.

Tick infestation and spotted-fever group Rickettsia in shelter dogs, California, 2009

In response to an outbreak of Rocky Mountain spotted fever (RMSF) in Baja California in early 2009, dogs at two shelters in neighbouring Imperial County, California, were evaluated for ectoparasites. Brown dog ticks (Rhipicephalus sanguineus), a recognized vector for RMSF, were found on 35 (30%) of 116 dogs but all ticks tested negative for Rickettsia rickettsii by PCR.

The New Unified International Diabetes Federation/American Heart Association/National Heart, Lung, and Blood Institute Metabolic Syndrome definition: does it correlate better with C-reactive protein in Chinese patients diagnosed with type 2 diabetes?

This study evaluated the association between high-sensitivity C-reactive protein (hsCRP) and metabolic syndrome, defined by the definition proposed by the International Diabetes Federation (IDF), American Heart Association (AHA) and National Heart, Lung, and Blood Institute (NHLBI) versus the older IDF definition, in 506 Chinese patients with type 2 diabetes. Anthropometric and biochemical parameters were compared and analysed using multivariate linear regression models. Serum hsCRP was higher in patients with metabolic syndrome compared with those without metabolic syndrome for both definitions and increased as the number of components of metabolic syndrome increased (after adjusting for age, gender and smoking). Patients with metabolic syndrome according to the IDF/AHA/NHLBI but not the IDF definition had significantly higher hsCRP levels than those not meeting either definition and similar hsCRP levels to those meeting both definitions. Serum hsCRP levels were significantly associated with metabolic syndrome according to the IDF definition after adjusting for age, gender and smoking. Adding metabolic syndrome status according to the IDF/AHA/NHLBI definition significantly increased the fit of the multivariate linear regression model. The new IDF/AHA/NHLBI definition of metabolic syndrome may have a stronger relationship with serum hsCRP than the IDF definition.

Glucose metabolism-related protein 1 (GMRP1) regulates pancreatic beta cell proliferation and apoptosis via activation of Akt signalling pathway in rats and mice

AIMS/HYPOTHESIS

We attempted to elucidate the impacts on and possible mechanisms by which glucose metabolism-related protein 1 (GMRP1) affects beta cell survival.

METHODS

Adenovirus-mediated GMRP1 overproduction and siRNA-mediated knockdown were performed in INS-1E cells and rat islets, after which cell proliferation or apoptosis were determined, and phosphorylation of Akt and BCL2-associated agonist of cell death (BAD) investigated. INS-1E cells and rat islets were cultured at 5.6 (low) or 25 mmol/l (high) glucose for 24 or 48 h, and cell proliferation or apoptosis and GMRP1 levels were investigated. INS-1E cells were treated for 24 h with 0, 10, 50 and 100 nmol/l insulin, and GMRP1 levels were determined. After INS-1E cells were transfected with siRNA for 72 h, high glucose-induced cell proliferation and insulin-stimulated Akt phosphorylation were investigated. Glucose-infused rat models were established and beta cell proliferation and mass were evaluated. Levels of GMRP1, and phosphorylation of Akt and BAD were determined in glucose-infused islets. The GMRP1-mediated Akt pathway was also investigated in db/db mice.

RESULTS

Overproduction of GMRP1 promoted beta cell proliferation via increased phosphorylation of Akt. Knockdown of Gmrp1 (also known as Btbd10) reduced phosphorylation of Akt with enhanced beta cell apoptosis. High glucose increased GMRP1 levels and cell proliferation in INS-1E cells and islet cells. Knockdown of Gmrp1 decreased high glucose-induced cell proliferation and insulin-stimulated Akt phosphorylation. Increased GMRP1 levels were involved in the enhancement of beta cell proliferation and mass in glucose-infused islets. Decreased GMRP1 levels may participate in beta cell apoptosis of db/db mice.

CONCLUSIONS/INTERPRETATION

GMRP1 regulates pancreatic beta cell proliferation and apoptosis via activation of Akt signalling pathway.

Combined Structural and Optical Assessment of CVD Grown 3C-SiC/Si

A combined structural and optical assessment of cubic (3C-) SiC thin films grown on Si (100) substrates by chemical vapor epitaxy (CVD) is presented. The CVD growth was performed at both atmospheric and low (100 Torr) pressure, using a vertical reactor. The CVD-grown 3C-SiC films with different growth time were characterized by X-ray diffraction, Raman scattering and Fourier transform infrared (FTIR) spectroscopy to be single crystalline with a high degree of crystal perfection. The film thickness was determined from FTIR spectra. Variations of X-ray, FTIR and Raman spectra with different growth conditions and film thicknesses are studied comparatively. Related problems are discussed.

Transcription specificity of the class Ib genes SLA-6, SLA-7 and SLA-8 of the swine major histocompatibility complex and comparison with class Ia genes

Our aim was to analyse the transcription levels of the three non-classical class Ib genes SLA-6, SLA-7 and SLA-8 of the swine major histocompatibility complex in various tissues and conditions and to compare them to the transcription levels of classical class Ia genes. Twenty-five adult tissues from two pig breeds, pig renal PK15 cells infected with the Pseudorabies virus, and peripheral blood mononuclear cells (PBMCs) stimulated by lipopolysaccharide or a mixture of phorbol myristate acetate and ionomycin were included in our study. Relative transcription was quantified by quantitative real-time PCR. On average, in adult tissues and PBMCs and compared to SLA-6, the transcription level of SLA-Ia genes was 100-1000 times higher, the level of SLA-8 was 10-20 times higher, and that of SLA-7 was five times higher. Thus, SLA-8 is the most transcribed SLA-Ib gene, followed by the SLA-7 and SLA-6 genes. The highest transcription levels of SLA-Ib transcripts were found in the lymphoid organs, followed by the lung and the digestive tract. The tissue variability of expression levels was widest for the SLA-6 gene, with a 1:32 ratio between the lowest and highest levels in contrast to a 1:12 ratio for the SLA-7 and SLA-8 genes and a 1:16 ratio for the SLA-Ia genes. During PK-15 infection and PBMC stimulation, SLA-Ia and SLA-8 genes were downregulated, whereas SLA-6 and SLA-7 were upregulated, downregulated or not significantly modified. Our overall results confirm the tissue-wide transcription of the three SLA-Ib genes and suggest that they have complementary roles.

A novel screening method of cellulase-producing bacteria

Cellulase is the key to utilize the renewable and abundant cellulose resource, cellulase-producing microorganism is an important source of cellulase. The traditional screening method of cellulase-producing microorganism is low efficacy and not macroscopic. The screening method in this study was based on the interactive culture character between cellulase-producing bacteria and Phytophthora parasitica var. nicotianae on plates, the results indicated that the inhibition zone and cellulase activity of bacterial strains are conformity on the whole, so the screening method is very quickly and apparent.

Gender-Dependent Penetrance of Small Heterodimer Partner (SHP) Gene Deficiency in Overweight/Obese Chinese Pedigrees

Mutations of the small heterodimer partner ( SHP) gene have been associated with mild obesity in Japanese subjects. This study was designed to investigate whether there was a similar association in 772 Chinese adults. A total of 272 subjects were normal weight, 423 were overweight and 77 were obese. Four non-synonymous mutations (R34X, H53fsdel10, G171A, G189E) were identified in 10 out of the 500 overweight/obese subjects, but were not seen in the normal weight controls (prevalence 2.00% versus 0.00%, respectively). The relatives of proband carriers, including 25 carriers and 33 non-carriers from three generations, were also screened for 10 multigenerational non-consanguineous pedigrees. A gender-dependent penetrance effect was observed in the pedigrees. Furthermore, the frequency of SHP gene mutations was significantly higher in those with type 2 diabetes compared with the non-diabetics (61.5% versus 28.1%, respectively). These data provide evidence of a gender-dependent effect on penetrance for SHP deficiency and suggest that SHP mutations increase susceptibility to type 2 diabetes.

Oxidative Stress and Apoptosis of Human Brain Microvascular Endothelial Cells Induced by Free Fatty Acids

Damage to endothelial cells is a key event in the pathogenesis of atherosclerosis and vascular disease. This study aimed to determine whether free fatty acids (FFAs) induced oxidative stress and apoptosis in human brain microvascular endothelial cells (HBMVECs) in vitro and, if so, which signalling pathway mediated these effects. After culture in different concentrations of FFAs for 24-72 h, cell viability/proliferation was determined using a cell counting kit, apoptosis was detected by measuring caspase-3 activity and by using annexin V-conjugated fluorescein isothiocyanate/propidium iodide staining, and oxidative stress was evaluated by measuring the levels of reactive oxygen species (ROS) and mitochondrial membrane potential (MMP). The HBMVECs exposed to FFAs showed significantly decreased cell proliferation, increased apoptosis and ROS levels, and decreased MMP. In conclusion, the results showed that high levels of FFAs induced oxidative stress, which damaged HBMVECs and resulted in apoptosis.

Effect of 14-3-3 tau protein on differentiation in BeWo choriocarcinoma cells

This study aimed to investigate the location and function of tau isoform of 14-3-3 proteins in human trophoblast. 14-3-3 tau was localized in human cytotrophoblast cells, but not in syncytiotrophoblast cells in both first trimester and term placenta by immunochemistry stain. Forskolin-induced cell fusion (BeWo cells) confirmed that 14-3-3 tau was decreased during trophoblast differentiation. Forskolin-induced differentiation was stimulated by small-interfering (si) RNA induced down-regulation of 14-3-3 tau, contrarily, it was suppressed by plasmid induced upregulation of 14-3-3 tau in BeWo cells. When BeWo cells were treated with 14-3-3 tau siRNA, an increase in protein concentration of cell cycle inhibitor p27kip1 and a decrease in protein concentration of proliferating cell nuclear antigen, as well as activation of the extracellular signal-regulated kinase (ERK) pathway, were also noticed. These findings suggest that 14-3-3 tau might be mediated trophoblast differentiation through cell cycle regulation.

The Association of Dysglycaemia and Cardiovascular Disease in Patients with Metabolic Syndrome

The objective of this study was to investigate the relationship between increased prevalence of cardiovascular disease and glucose regulation status in Chinese patients with metabolic syndrome (MetS). All patients underwent an oral glucose tolerance test (2-h post-load plasma glucose) to determine their glucose regulation status and had their brachial–ankle pulse wave velocity (baPWV) measured. Of the 590 patients included in the study, 115 (19.5%) had normal glucose tolerance, 114 (19.3%) had impaired fasting glucose (IFG) alone, 38 (6.4%) had impaired glucose tolerance (IGT) alone, 197 (33.4%) had diabetes mellitus and 126 (21.4%) had combined glucose intolerance (CGI; IFG plus IGT). Patients with diabetes mellitus had a significantly higher baPWV compared with all other groups and patients with CGI had a significantly higher baPWW compared with patients with IFG. Dysglycaemia was common in patients with MetS. An increased prevalence of cardiovascular disease in patients with MetS was related to their glucose regulation status.

A common variant in MTNR1B, encoding melatonin receptor 1B, is associated with type 2 diabetes and fasting plasma glucose in Han Chinese individuals

AIMS/HYPOTHESIS

Recently, three groups independently reported that variation in MTNR1B, the gene encoding melatonin receptor 1B, was associated with an increased risk of type 2 diabetes, increased fasting plasma glucose and impaired insulin secretion in populations of European ancestry. In the present study, we investigated whether a single MTNR1B polymorphism was associated with type 2 diabetes in Han Chinese individuals, to elucidate whether this is a cross-populational effect.

METHODS

The MTNR1B variant rs10830963 was genotyped in 1,165 type 2 diabetic patients and 1,105 normoglycaemic control individuals of southern Han Chinese ancestry who were residents of the metropolitan area of Shanghai. The risk of developing type 2 diabetes was calculated using a logistic regression model adjusted for age, sex and BMI. A possible association with fasting plasma glucose was analysed in the normoglycaemic control individuals using a multiple linear regression analysis with adjustments for age, sex and BMI.

RESULTS

The genetic variant rs10830963 was associated with an increased risk of type 2 diabetes in our Han Chinese cohort (OR 1.16, 95% CI 1.03-1.31, p = 0.015). As previously described, the risk variant was also associated with increased fasting plasma glucose, showing an increase of 0.068 mmol/l (95% CI 0.036-0.100, p = 4 x 10(-5)) per risk allele.

CONCLUSIONS/INTERPRETATION

A common variant in the MTNR1B gene is associated with an increased risk of type 2 diabetes and increased fasting plasma glucose in Han Chinese, suggesting an important role for this polymorphism in populations of different ethnic and environmental backgrounds.

Hyperbaric oxygen preconditioning protects against traumatic brain injury at high altitude

BACKGROUND

Recent studies have shown that preconditioning with hyperbaric oxygen (HBO) can reduce ischemic and hemorrhagic brain injury. We investigated effects of HBO preconditioning on traumatic brain injury (TBI) at high altitude and examined the role of matrix metalloproteinase-9 (MMP-9) in such protection.

METHODS

Rats were randomly divided into 3 groups: HBO preconditioning group (HBOP; n = 13), high-altitude group (HA; n = 13), and high-altitude sham operation group (HASO; n = 13). All groups were subjected to head trauma by weight-drop device, except for HASO group. HBOP rats received 5 sessions of HBO preconditioning (2.5 ATA, 100% oxygen, 1 h daily) and then were kept in hypobaric chamber at 0.6 ATA (to simulate pressure at 4000m altitude) for 3 days before operation. HA rats received control pretreatment (1 ATA, room air, 1 h daily), then followed the same procedures as HBOP group. HASO rats were subjected to skull opening only without brain injury. Twenty-four hours after TBI, 7 rats from each group were examined for neurological function and brain water content; 6 rats from each group were killed for analysis by H&E staining and immunohistochemistry.

RESULTS

Neurological outcome in HBOP group (0.71 +/- 0.49) was better than HA group (1.57 +/- 0.53; p < 0.05). Preconditioning with HBO significantly reduced percentage of brain water content (86.24 +/- 0.52 vs. 84.60 +/- 0.37; p < 0.01). Brain morphology and structure seen by light microscopy was diminished in HA group, while fewer pathological injuries occurred in HBOP group. Compared to HA group, pretreatment with HBO significantly reduced the number of MMP-9-positive cells (92.25 +/- 8.85 vs. 74.42 +/- 6.27; p < 0.01).

CONCLUSIONS

HBO preconditioning attenuates TBI in rats at high altitude. Decline in MMP-9 expression may contribute to HBO preconditioning-induced protection of brain tissue against TBI.

Genetic and QTL analysis of resistance to Xiphinema index in a grapevine cross

Resistance to the dagger nematode Xiphinema index has been an important objective in grape rootstock breeding programs. This nematode not only causes severe feeding damage to the root system, but it also vectors grapevine fanleaf virus (GFLV), the causal agent of fanleaf degeneration and one of the most severe viral diseases of grape. The established screening procedures for dagger nematode resistance are time consuming and can produce inconsistent results. A fast and reliable greenhouse-based system for screening resistance to X. index that is suitable for genetic studies and capable of evaluating breeding populations is needed. In this report, the dynamics of nematode numbers, gall formation, and root weight loss were investigated using a variety of soil mixes and pot sizes over a 52-week period. Results indicated that the number of galls formed was correlated with the size of the nematode population and with the degree of root weight loss. After inoculation with 100 nematodes, gall formation could be reliably evaluated in 4-8 weeks in most plant growth conditions and results were obtained 6 months more rapidly than past evaluation methods. This modified X. index resistance screening method was successfully applied to 185 of the 188 F(1) progeny from a cross of D8909-15 x F8909-17 (the 9621 population), which segregates for a form of X. index resistance originally derived from Vitis arizonica. Quantitative trait loci (QTL) analysis was carried out on both parental genetic maps of 255 markers using MapQTL 4.0. Results revealed that X. index resistance is controlled by a major QTL, designated Xiphinema index Resistance 1 (XiR1), near marker VMC5a10 on chromosome 19. The XiR1 QTL was supported by a LOD score of 36.9 and explained 59.9% of the resistance variance in the mapping population.

Performance and comparison of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease formulae in estimating glomerular filtration rate in a Chinese Type 2 diabetic population

AIMS

Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks.

METHODS

A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared.

RESULTS

The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks.

CONCLUSIONS

These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.

Functional characterization of TIP60 sumoylation in UV-irradiated DNA damage response

The histone acetyltransferase TIP60 regulates the DNA damage response following genotoxic stress by acetylating histone and remodeling chromatin. However, the molecular mechanisms underlying the TIP60-dependent response to UV-induced DNA damage remain poorly understood. To systematically analyse proteins that regulate TIP60 activity in response to UV irradiation, we performed a proteomic analysis of proteins selectively bound to TIP60 in response to UV irradiation using mass spectrometry and identified a novel regulatory mechanism by which TIP60 orchestrates transcriptional activation of p53-dependent checkpoint response in UV-irradiated cells. The initial step of this pathway involves UV-induced association of TIP60 with SUMO-conjugation enzymes and site-specific sumoylation of TIP60 at lysines 430 and 451 via Ubc9. This sumoylation initiates the relocation of TIP60 from nucleoplasm to the promyelocytic leukemia body, which is essential for the UV-irradiated DNA damage repair response via a p53-dependent pathway. Significantly, inhibition of TIP60 sumoylation by overexpression of non-sumoylatable mutant abrogates the p53-dependent DNA damage response, demonstrating the importance of TIP60 sumoylation in response to UV irradiation. Our biochemical characterization demonstrated that the sumoylation of TIP60 augments its acetyltransferase activity in vitro and in vivo. Thus, this study shed new light on the function and regulation of TIP60 activity in UV-irradiated DNA damage response.

Comparative toxicity of hydrophobic contaminants to microalgae and higher plants

To enable rapid and sensitive screening of phytotoxic compounds in terrestrial system, a 4 day solid-phase microalgal bioassay was developed. Three species of microalgae (Selenastrum capricornutum, Chlorococcum hypnosporum and Chlorococcum meneghini) were chosen to investigate their responses to DDTs (DDT, DDD and DDE) and PAHs (naphthalene, phenanthrene and pyrene) spiked sands. The bioassay results showed that PAHs and DDTs were toxic to microalgae in a 4-day exposure tests but not to seed germination of ryegrass (Lolium perenne). Phenanthrene was the most phytotoxic. Among three investigated endpoints, fluorescence emissions by microalgae were less sensitive than cell density (optical density OD(650)) and chlorophyll a concentration as endpoints. In general, S. capricornutum was the most sensitive species for PAHs (EC(50) for phenanthrene = 9.4 mg kg(-1)), while C. meneghini for DDTs (EC(50) for DDE = 20.0 mg kg(-1)). Comparison of the microalgal tests with US EPA standard seed germination/root elongation test (using Lolium perenne) demonstrated the superior screening potential of phytotoxic hydrophobic compounds using the proposed bioassay. Using OD(650) as the endpoint, EC(10) of selected microalgae for PAHs and DDTs were 0.43-64.3 mg kg(-1) and 0.67-117 mg kg(-1) respectively, which were much lower than the EC(10) of L. perenne for both PAHs (94-187 mg kg(-1)) and DDTs (113-483 mg kg(-1)). The results encourage further studies involving wider types of vascular plants and more comparison with standard phytotoxicity tests from different authorities using contaminated soils to verify the effectiveness of the microalgal bioassay.

Screening of PAHs and DDTs in sand and acrisols soil by a rapid solid-phase microalgal bioassay

Previously we have demonstrated the rapid screening potential of a newly developed solid-phase microalgal bioassay with spiked sands. In this paper, we report further comparative results using both PAHs and DDTs spiked sands and field-collected acrisols soils. Toxicity responses obtained from standard higher plant tests with three species of plants (Lolium perenne, Cynodon dactylon and Brassica chinensis) were compared with those obtained from a cocktail of microalgae (Selenastrum capricornutum, Chlorococcum hypnosporum and the indigenous Chlorococcum meneghini). The 5-day seed germination/root elongation tests were not sensitive at all in contrast to the 4-day solid-phase microalgal tests and the 28-day early seedling growth tests in both spiked sands and contaminated soils. Sensitivities of microalgal tests were generally higher than the seedling growth tests in spiked sands. Concerning the assays with contaminated soil, the responses of microalgae and higher plants varied. However, the results demonstrated that microalgae could generally act as effective surrogates to screen xenobiotic compounds at toxic level to higher plants, with the local species C. meneghini especially sensitive to reveal phytotoxic effects. This promising rapid screening solution is possible to be used in accompany with standard seedling growth tests when assessing phytotoxicities of contaminated areas, especially for acrisols soil.

Characterization of urinary peptide biomarkers of acute rejection in renal allografts

We previously demonstrated that 4.7 kDa and 4.4 kDa peptides are useful in diagnosing acute rejection in renal transplant recipients. The aim of this study was to characterize these polypeptides and assess their potential as biomarkers. The polypeptides were identified as human beta-Defensin-1 (4.7 kDa) and alpha-1-antichymotrypsin (4.4 kDa), by tandem mass spectrometry and ProteinChip immunoassay. The urinary abundance of both polypeptides, assessed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS), revealed a reduction in beta-Defensin-1 while alpha-1-antichymotrypsin increased in patients with rejection (p < 0.05) compared with clinically stable transplants. The area under the curve (AUC) for the receiver operator characteristic (ROC) curve for the diagnosis of rejection for the ratio of both peptides combined was 0.912. Longitudinal analysis confirmed a reduction in beta-Defensin-1 with a reciprocal increase in alpha-1-antichymotrypsin as rejection developed. The difference in urinary beta-Defensin-1 levels quantified by radioimmunoassay was 176.8 +/- 122.3 pg/mL in stable patients compared with 83.2 +/- 52.2 pg/mL in patients with acute rejection, with an ROC AUC of 0.749 (p < 0.01). Immunohistochemistry (IHC) confirmed reduced beta-Defensin-1 expression in the renal parenchyma of patients experiencing acute rejection. In conclusion, the ratio of beta-Defensin-1 and alpha-1-antichymotrypsin excretion in the urine is a novel, potentially useful candidate biomarkers of acute rejection.

Pollutants in Hong Kong soils: polycyclic aromatic hydrocarbons

An extensive soil survey was carried out to study the polycyclic aromatic hydrocarbon (PAH) contaminations in 138 soil samples collected throughout Hong Kong. Results demonstrated that there were low levels of PAH contaminations (median of summation operator 16US EPA PAHs=140 microg kg(-1)) for all land uses (urban park, greening area, country park, rural area, restored landfill, agricultural farmland, orchard farm, crematorium, industrial and near highway area). However, localized hotspots were identified with summation operator 16PAH concentrations as high as 19,500 microg kg(-1) in one urban park. These findings were also confirmed by multivariate analysis. Comparison of PAH profiles showed a widespread domination of its 4-ring member. The major contribution was vehicular emissions from petroleum, and however at the hotspots, the improper disposal of used motor oils. In general, the pollution levels for all the land uses were below the recommended values for residential and general purposes stated in soil quality guidelines such as Netherlands and Denmark except certain identified hotspots. The potential health hazards imposed by these hotspots were alarming, and their existence (3 out of 138 samples) suggested that sole monitoring of atmospheric PAHs may not adequately address the hidden risks to human in urban city.

Astrocyte-derived estrogen enhances synapse formation and synaptic transmission between cultured neonatal rat cortical neurons

Recent in vitro studies have found that astrocytes exert powerful control over the number of neuronal synapses, leading us to consider why glia can exert this control and what the underlying mechanism(s) may be. To understand the potential possibility, we studied the formation of synapses and synaptic function in primary rat cortical neurons. We found that primary cultured neonatal rat cortical astrocytes modulate synaptogenesis and synaptic function through producing and secreting estradiol into culture medium. The concentration of estradiol produced by pure cultured astrocytes increased in correspondence with the days of culture and the number of proliferating astrocytes, which peaked at 266+/-22 ng/l around day 14 of culture. When astrocyte-conditioned medium (ACM) was added into pure cultured cortical neurons, the number of synapses formed between cortical neurons increased by nearly sixfold. The mean frequency and the amplitude of mini-postsynaptic currents (mPSCs) increased from 13+/-4 events/min and 20.5+/-2 pA to 73+/-16 events/min and 29.1+/-3 pA, respectively. In the meantime, the level of estrogen receptor-alpha (ER-alpha) expressed on neonatal rat cortical neurons was significantly up-regulated. Moreover, the effect of ACM on synaptic formation and transmission was blocked by tamoxifen (estrogen receptor antagonist) in culture. After the treatment of tamoxifen, the number of synapses on neurons decreased from 79+/-9 to 32+/-3. The mean amplitude and frequency of mPSCs were also dropped to 24.5+/-2 pA and 35+/-10/min, respectively. Unexpectedly, exogenic estradiol can mimic the effect of ACM on synaptic formation and transmission. Finally, to understand whether astrocyte-derived estradiol regulates the synaptic transmission via presynapse, the release of presynaptic vesicle from neuron was monitored by FM 4-64 assay. The results showed that when ACM or exogenic estradiol was added into neurons, the kinetics of vesicle release speed are similar to that of neuronal cultured with astrocytes, which were faster than that of just pure neuronal cultures. These observations suggest that estrogen synthesized and secreted by astrocytes can regulate synapse formation and synaptic transmission.

Microarray-based compendium of hepatic gene expression profiles for prototypical ADME gene-inducing compounds in rats and mice in vivo

To examine species-specific aspects of the induction of absorption, distribution, metabolism and excretion (ADME)-related genes, we used 25 000 gene oligonucleotide microarrays to construct a rodent gene-response compendium that compared hepatic gene expression profiles and developed consensus aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR) and pregnane X-receptor (PXR) ligand signatures relevant to drug clearance. Twenty-six inducer compounds were chosen from the literature. Rats and mice received one of six dose levels (log2 dose escalation, 32-fold dose range) of each compound daily for 3 days. Animals were necropsied 6-9 h after the last dose, and tissues were collected for RNA analysis. Hepatic gene expression profiles were obtained using Rosetta Resolver expression analysis system, and ADME-related genes were extracted. Cross-talk among nuclear receptors or hepatoxicity at high dose levels resulted in large signatures (usually >1000 genes at p < 0.01) for most compounds. After ADME gene transcript enrichment, agglomerative clustering separated AhR ligands from CAR/PXR ligands, but it was difficult to distinguish CAR from PXR ligands. Consensus signatures were derived from groups of AhR, CAR and PXR ligands; and cross-talk among responding genes was determined. Many compounds had distinct log dose-response profiles, and relative potencies for ligands were established. Robust responses by CYP1A1, CYP2B10 (CAR responsive in mice) and CYP2B15 (CAR responsive in rats) and CYP3A1 (PXR responsive in rats) were used to benchmark the relative potency of different ligands and to determine the relative selectivity for AhR, CAR or PXR. By using a compendium of gene expression profiles, we defined species-specific induction patterns across the ADME transcriptome.

Proteomic analysis of hypoxia-induced responses in the syncytialization of human placental cell line BeWo

Syncytiotrophoblast formation is affected by a number of pathological conditions and suppressed syncytiotrophoblast formation due to hypoxia may play a role in the pathogenesis of preeclampsia. However, the molecular basis of hypoxia-inhibited trophoblast syncytialization is poorly understood. To determine the effect of hypoxia on trophoblast syncytialization, a proteomic analysis was performed in the human cytotrophoblast cell line BeWo using two-dimensional electrophoresis and MALDI-TOF-TOF-MS. Hypoxia induced marked inhibition of BeWo cell fusion and differentiation. The proteomic profiling was established under hypoxia in BeWo cell syncytialization. The results showed that twenty proteins were significantly up-or down-regulated under hypoxia, compared with cells under normoxia. In response to hypoxia, three antioxidants, peroxiredoxin 1, peroxiredoxin 2 and 1-Cys peroxiredoxin, were down-regulated, two proteins involved in glycolysis pathway (malate dehydrogenase and enolase) were up-regulated. The expression of two members of the annexin family (annexin A2 and annexin A5) increased. We also found a decreased expression of 14-3-3 tau protein in hypoxia treated cells. Proteins implied in protein degradation and folding were also identified. The expression of two cytoskeleton components (keratin 1 and beta-actin) was found to be down-regulated. In addition, galectin-3 was up-regulated. These proteins have been implicated in regulating cellular oxidative stress, glycolysis, signal transduction, protein folding and degradation, cell mobility and cytoskeletal structure formation. Western blot analysis revealed that the levels of peroxiredoxin 1 and 14-3-3 tau decreased, whereas the levels of annexin A5 and annexin A2 increased in BeWo cells under hypoxia. These findings provided new insights into the molecular mechanisms in mediating cellular response to hypoxia in trophoblast syncytialization.

Mutant B-RAF signaling and cyclin D1 regulate Cks1/S-phase kinase-associated protein 2-mediated degradation of p27Kip1 in human melanoma cells

Levels of cyclins and cyclin-dependent kinase (Cdk) inhibitors are tightly controlled during normal cell proliferation and are frequently dysregulated in cancerous cells. In melanoma, cyclin D1 is highly expressed and downregulation of the Cdk inhibitor, p27(Kip1), is associated with a poor prognosis. Mutant B-RAF is frequently expressed in melanoma and overrides growth factor and matrix adhesion control of cyclin D1 and p27(Kip1) levels in human melanocytes. Here, we demonstrate that p27(Kip1) expression is regulated by multiple mechanisms in melanoma cells. B-RAF regulates p27(Kip1) mRNA abundance independently of cyclin D1. Additionally, B-RAF and cyclin D1 control the levels of S-phase kinase-associated protein 2 (Skp2) that directs ubiquitin-mediated proteolysis of p27(Kip1). The cofactor for Skp2, Cdc kinase subunit 1 (Cks1) controls levels of Skp2 in melanoma cells and acts jointly with Skp2 to regulate p27(Kip1) levels. Importantly, expression of Cks1 is regulated by B-RAF and cyclin D1 at the mRNA level. Reduced Cks1 or Skp2 expression and enhanced p27(Kip1) levels inhibit melanoma cell growth. In summary, p27(Kip1) expression in melanoma is regulated by B-RAF at the mRNA level, and via B-RAF and cyclin D1 control of Cks1/Skp2-mediated proteolysis.

A GPI-anchored co-receptor for tissue factor pathway inhibitor controls its intracellular trafficking and cell surface expression

BACKGROUND

Tissue factor pathway inhibitor (TFPI) lacks a membrane attachment signal but it remains associated with the endothelial surface via its association with an, as yet, unidentified glycosyl phosphatidylinositol (GPI)-anchored co-receptor.

OBJECTIVES/METHODS

Cellular trafficking of TFPI within aerolysin-resistant ECV304 and EA.hy926 cells, which do not express GPI-anchored proteins on their surface, was compared with their wild-type counterparts.

RESULTS AND CONCLUSIONS

Although aerolysin-resistant cells produce normal amounts of TFPI mRNA, TFPI is not expressed on the cell surface and total cellular TFPI is greatly decreased compared with wild-type cells. Additionally, normal, not increased, amounts of TFPI are secreted into conditioned media indicating that TFPI is degraded within the aerolysin-resistant cells. Confocal microscopy and studies using metabolic inhibitors demonstrate that aerolysin-resistant cells produce TFPI and transport it into the Golgi with subsequent degradation in lysosomes. The experimental results provide no evidence that cell surface TFPI originates from secreted TFPI that binds back to a GPI-anchored protein. Instead, the data suggest that TFPI tightly, but reversibly, binds to a GPI anchored co-receptor in the ER/Golgi. The co-receptor then acts as a molecular chaperone for TFPI by trafficking it to the cell surface of wild-type cells or to lysosomes of aerolysin-resistant cells. TFPI that escapes co-receptor binding is secreted through the same pathway in both wild-type and aerolysin-resistant cells. The data provide a framework for understanding how TFPI is expressed on endothelium.

Analysis of off-flavor compounds in water at sub part per trillion level by GC/MS with programmable temperature vaporizer inlet

"Earthy-musty" off-flavor problems in water samples are due to organic compounds present at the sub part per trillion level. Most of the studies in the analysis of tastes and odorous compounds focus on the extraction pre concentration technique, with detection at picogram per liter level of the earthy-musty off-flavor compounds, which are difficult to achieve. The objective of this study is to develop a new method involving the GC/MS with programmable temperature vaporizer (PTV) inlet via large volume injection (LVI) or solid phase micro-extraction (SPME), to attain analytical sensitivity equal to or better than olfactory sensitivity. Six "earthy-musty" organic compounds; 2-methylisoborneol (MIB); geosmin; 2, 4, 6-trichloroanisole (2,4,6-TCA); 2, 3, 6-trichloroanisole (2,3,6-TCA); 2, 3, 4-trichloroanisole (2,3,4-TCA); and 2, 4, 6-tribromoanisole (2,4,6-TBA), were used as probes for this study. It was found that LVI via PTV could greatly improve system sensitivity towards the detection of off-flavor compounds with low volatility such as haloanisoles. For those off-flavor compounds with high volatility, eg MIB, SPME coupled with PTV-GC-MS with cool initial temperature has always demonstrated the best sensitivity.

Structural Characterization of Nickel Oxide Nanowires by X-ray Absorption Near-Edge Structure Spectroscopy

Nickel oxide nanowires modified by poly(vinylpyrrolidone) (PVP) were synthesized via a simple chemical pattern. For the first time NiO nanowires with diameters ranging from 40 to 100 nm with the expected ratio (length vs diameter) ranging from 54 to 90 were grown using a simple solution-phase approach (mild method). These nickel nanowires exhibited unique photoluminescence features and displayed a significant UV luminescence. X-ray absorption near-edge spectroscopy has been used to characterize the local Ni environment and identify the electronic structure. Comparing experimental and theoretical spectra at the Ni and O K edges, we determine the lattice distortion via the analysis of the characteristic preedge features and the multiple-scattering structures detected in the X-ray absorption near-edge structure spectra. The correlation between experimental features and the disordered or distorted local structures is also discussed.

[The single nucleotide polymorphisms and its application to forensic medicine]

Single-nucleotide polymorphisms (SNPs) are the most abundant forms of human genetic variation. These variable sites are present at high density in the genome, making them powerful tool for the diagnosis of genetic and genetic-related diseases, population genetics research and drug development. They are also found widespread application to the forensic medicine. This report mainly describe the SNPs characteristics and its potential applications to the forensic medicine including the possibility, the problems and high-throughput automation detection methods.

Signal transduction events elicited by cancer prevention compounds

Many chemopreventive agents have been shown to modulate gene expression including induction of phase II detoxifying enzymes, such as glutathione S-transferases (GST) and quinone reductases (QR). Induction of phase II enzymes in general leads to protection of cells/tissues against exogenous and/or endogenous carcinogenic intermediates. The antioxidant or electrophile response element (ARE/EpRE) found at the 5'-flanking region of these phase II genes may play important role in mediating their induction by xenobiotics including chemopreventive agents. Members of the basic leucine zipper (bZIP) transcription factor, Nrf2 which heterodimerizes with Maf G/K, are found to bind to the ARE, and transcriptionally-activated ARE. Recently, we showed that the mitogen-activated protein kinases (MAPK) were activated by phase II gene inducers such as phenolic antioxidant butylated hydroxyanisol (BHA) and isothiocyanate sulforaphane (SUL), and involved in the transcription activation of ARE-mediated reporter gene. Transfection studies with wild-type and dominant negative mutants of Nrf2 and MAPK showed synergistic response during co-transfection as well as to phase II gene inducers. However, increasing the concentrations of these compounds such as BHA, the activities of cell death signaling molecules, caspases, were stimulated and resulted in apoptotic cell death. At these concentrations, BHA stimulated loss of mitochondrial membrane potential, cytochrome c release, and activation of caspase 3, 8 and 9 preceding apoptosis. Further increase in concentrations led to rapid cell necrosis. A model is proposed for BHA and SUL, in that at low concentrations, these potential chemopreventive agents may modulate MAPK pathway leading to transcription activation of Nrf2 and ARE with subsequent induction of cellular defensive enzymes including phase II detoxifying enzymes as well as other defensive genes, which may protect the cells against cellular injury, which is a homeostatic response. At higher concentrations, these agents may activate the caspase pathways, leading to apoptosis, a potential beneficial effect if occurs at preneoplastic/neoplastic tissues, but a potential cytotoxic response if occurs in normal tissues. On the other hand, some phenolic compounds such as resveratrol inhibits TPA- or UV-induced AP-1-mediated activity through the inhibition of c-Src non-receptor tyrosine kinase and MAPK pathways. It is possible that in proliferating or stimulated cells, these chemopreventive compounds may block proliferation by inhibiting these signaling kinases, whereas in non-proliferating or quiescent cells, some of these compounds may activate these signaling kinases leading to gene expression of cellular defensive enzymes such as phase II detoxifying enzymes. The studies of these and other signaling pathways may yield insights into the development of potential chemopreventive compounds.

[Determination of rutin and quercetin in mulberry leaves by high performance capillary electrophoresis]

Rutin and quercetin are the main effective components of mulberry leaves with the functions of controlling the increase of fat in serum and controlling the formation of arterio-sclerosis. In this article a high performance capillary electrophoretic(HPCE) method was used to separate and determine rutin and quercetin in mulberry leaves collected from different periods, different places and different kinds in Xinjiang. Electrophoretic conditions were as follows: a capillary tube (75 microns i.d. x 57 cm (effective length, 50 cm)), with 10 mmol/L dihydrogen sodium phosphate-20 mmol/L sodium borate containing 15% methanol as the running buffer (pH 8.62) and an applied voltage of 20 kV, at 25 degrees C, detected at a wavelength of 245 nm. Under the optimum conditions, rutin and querctin were separated successfully from other components within 12 minutes. The corrected peak areas of rutin and quercetin increased linearly with the increase of their concentrations in the range of 4.4 mg/L-28.8 mg/L and 1.8 mg/L-145.8 mg/L respectively. The corresponding regression equations for rutin and quercetin were Y = 71.60 rho + 30.51 (r = 0.9991) and Y = 315.17 rho - 929.70 (r = 0.9949) respectively, and the recoveries were 95.64% and 99.36%. The analytical results demonstrate the method is simple, quick and well reproducible, and can be used as a reliable tool for the quality control of mulberry leaves.

Human IFN-alpha protein engineering: the amino acid residues at positions 86 and 90 are important for antiproliferative activity

Human IFN-alpha is a family of structurally related proteins that exhibit a wide range of antiproliferative activities. To understand the structural basis for these different antiproliferative activities, eight recombinant human IFN-alpha hybrids (HY) of alpha21a/alpha2c (HY-4, HY-5) and mutants (site-directed mutagenesis (SDM)-1, 2 and cassette mutagenesis (CM)-1, 2, 3, and 4) have been expressed, purified, and characterized. The data showed that the amino acid region 81-95 is important for antiproliferative activity. Site-directed mutagenesis and cassette mutagenesis studies showed that if serine (S) 86 and asparagine (N) 90 were replaced by tyrosine (Y), the antiproliferative activity was increased. We have also observed that if Y86 was replaced by isoleucine (I), the antiproliferative activity was comparable. However, if Y86 was replaced by aspartic acid (D), lysine (K), or alanine (A), the antiproliferative activity was substantially decreased. Our results indicate that Y and/or I at position 86 and Y at position 90 are very important in antiproliferative activity of human IFN-alpha. Circular dichroism spectra showed that the amino acid replacements at position 86 did not change the secondary structure. Thus the biological activity changes among those mutants do not appear to be due to conformational changes. The results also suggest that hydrophobic residue(s) at position 86 may be important for the interaction of the molecule with its receptor. The competitive binding data correlated with the antiproliferative activity. The N-terminal region of the molecule and the hydrophobic residues (including Y and I) on the C-helix region at positions 86 and/or 90 are important for binding and antiproliferative activities of human IFN-alphas.

Induction of xenobiotic enzymes by the MAP kinase pathway and the antioxidant or electrophile response element (ARE/EpRE)

Cellular responses to xenobiotic-induced stress can signal proliferation, differentiation, homeostasis, apoptosis, or necrosis. To better understand the underlying molecular mechanisms after exposure to xenobiotics or drugs, we studied the signal transduction pathways, the mitogen-activated protein kinase (MAPK), and the basic leucine zipper transcription factor Nrf2, activated by different agents in the induction of Phase II drug metabolizing enzymes (DMEs). The MAPKs, characterized as proline-directed serine/threonine kinases, are essential components of signaling pathways that convert various extracellular signals into intracellular responses through serial phosphorylation cascades. Once activated, MAPKs can phosphorylate many transcription factors, such as c-Jun, ATF-2, and ultimately lead to changes in gene expression. Two classes of Phase II gene inducers, which are also cancer chemopreventive agents, were studied: (1) the phenolic antioxidants, namely butylated hydroxyanisole (BHA) and its active de-methylated metabolite t-butylhydroquinone (tBHQ), and phenolic flavonoids such as green tea polyphenols (GTP) and (-)-epigallocatechin-3-gallate (EGCG); and (2) the naturally occurring isothiocyanates, namely phenethyl isothiocyanate (PEITC), and sulforaphane. BHA and tBHQ are both well-known phenolic antioxidants used as food preservatives, and strongly activate c-Jun N-terminal kinase 1 (JNK1), extracellular signal-regulated protein kinase 2 (ERK2), or p38, in a time- and dose-dependent fashion. Free radical scavengers N-acetyl-L-cysteine (NAC), or glutathione (GSH), inhibited ERK2 activation and, to a much lesser extent, JNK1 activation by BHA/tBHQ, implicating the role of oxidative stress. Under conditions where MAPKs were activated, BHA or GTP also activated ARE/EpRE (antioxidant/electrophile response element), with the induction of Phase II genes such as NQO. Transfection studies with various cDNAs encoding wild-type or dominant-negative mutants of MAPKs and/or transcription factor Nrf2, substantially modulated ARE-mediated luciferase reporter activity in the presence or absence of phenolic compounds. Other phytochemicals including PEITC, and sulforaphane, also differentially regulated the activities of MAPKs, Nrf2, and ARE-mediated luciferase reporter gene activity and Phase II enzyme induction. A model is proposed where these xenobiotics (BHA, tBHQ, GTP, EGCG, PEITC, sulforaphane) activate the MAPK pathway via an electrophilic-mediated stress response, leading to the transcription activation of Nrf2/Maf heterodimers on ARE/EpRE enhancers, with the subsequent induction of cellular defense/detoxifying genes including Phase II DMEs, which may protect the cells against toxic environmental insults and thereby enhance cell survival. The studies of these signaling pathways may yield insights into the fate of cells upon exposure to xenobiotics.

[Fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid]

A fluorescence quenching method for the determination of p-hydroxyphenylpyruvic acid with trytophan in the medium pH 11.01 NH3-NH4Cl is studied. The calibration curve is linear for p-hydroxyphenylpyruvic acid from 0 to 15 micrograms.mL-1 with lambda ex/lambda em = 285/356 nm. The detection limit is 0.37 microgram.mL-1. Twenty replicate determinations of solutions containing 10 micrograms.mL-1 p-hydroxyphenylpyruvic acid show a relative standard deviation of 1.2%. This method can be applied to the determination of p-hydroxyphenylpyruvic acid in serum with satisfactory results.