High glucose induces dysfunction and apoptosis in endothelial cells: is the effect of high glucose persistence more important than concentration?

Oxidative stress and inflammation are involved in the pathogenesis of diabetic endothelial dysfunction. Herein we reported the biological changes induced by hyperglycemia in human umbilical vein endothelial cells (HUVECs) and the potential underlying mechanisms sought to determine whether high glucose concentration or the persistence plays a key role in the development of vascular lesions. The HUVECs were exposed to various glucose concentrations (5, 15, 30, and 60 mmol/L of D-glucose supplemented), and several oxidative stress factors, such as NO, NOS, and ROS, and inflammatory signaling markers, such as TNF-α, TNFR, RIP, TRADD, TRAF-2 and NF-κB, were analyzed at various times (24, 48, 72, and 96 h). High glucose (HG) induced a transient increase of NO within 24 h and decreased afterwards, in accord with the expression of eNOS. HG also increased ROS and TNF-α production and activated the TNF-α-mediated signal transduction, decreasing cell viability and inducing apoptosis. However, 3 HG groups had similar effects on HUVECs with the increased duration of exposure, which resulted in the amplified oxidative and inflammatory damage. Taken together, these findings suggest that the HG persistence exacerbates oxidative stress and activates the inflammatory-mediated signaling pathways, inducing endothelial dysfunction and apoptosis, regardless of the concentration of HG. Our results provide the first evidence that HG persistence is more important than concentration in the progress of diabetic endothelial dysfunction.

Ablation of AMP-activated protein kinase alpha1 and alpha2 from mouse pancreatic beta cells and RIP2.Cre neurons suppresses insulin release in vivo

AIMS/HYPOTHESIS

AMP-activated protein kinase (AMPK) is an evolutionarily conserved enzyme and a target of glucose-lowering agents, including metformin. However, the precise role or roles of the enzyme in controlling insulin secretion remain uncertain.

METHODS

The catalytic alpha1 and alpha2 subunits of AMPK were ablated selectively in mouse pancreatic beta cells and hypothalamic neurons by breeding Ampkalpha1 [also known as Prkaa1]-knockout mice, bearing floxed Ampkalpha2 [also known as Prkaa2] alleles (Ampkalpha1 ( -/- ),alpha2( fl/fl ),), with mice expressing Cre recombinase under the rat insulin promoter (RIP2). RIP2 was used to express constitutively activated AMPK selectively in beta cells in transgenic mice. Food intake, body weight and urinary catecholamines were measured using metabolic cages. Glucose and insulin tolerance were determined after intraperitoneal injection. Beta cell mass and morphology were analysed by optical projection tomography and confocal immunofluorescence microscopy, respectively. Granule docking, insulin secretion, membrane potential and intracellular free Ca(2+) were measured with standard techniques.

RESULTS

Trigenic Ampkalpha1 ( -/- ),alpha2( fl/fl ) expressing Cre recombinase and lacking both AMPKalpha subunits in the beta cell, displayed normal body weight and increased insulin sensitivity, but were profoundly insulin-deficient. Secreted catecholamine levels were unchanged. Total beta cell mass was unaltered, while mean islet and beta cell volume were reduced. AMPK-deficient beta cells displayed normal glucose-induced changes in membrane potential and intracellular free Ca(2+), while granule docking and insulin secretion were enhanced. Conversely, betaAMPK transgenic mice were glucose-intolerant and displayed defective insulin secretion.

CONCLUSIONS/INTERPRETATION

Inhibition of AMPK activity within the beta cell is necessary, but not sufficient for stimulation of insulin secretion by glucose to occur. AMPK activation in extrapancreatic RIP2.Cre-expressing cells might also influence insulin secretion in vivo.

Effect of the ratios of diameter of silo to bead on the pressure screening in granular columns

We present the apparent mass measurements at the bottom of granular packings for different bead and silo sizes. The redirection parameter K in Janssen theory is found to increase with the ratios of the diameter of the silo to the bead. We attribute this feature to the friction between the beads and the confining wall of silo; it is the role of friction that leads to variations in the shielding of vertical stresses as well as pressure screening.

PACE+ Nutrition and Exercise Counseling for Obese Patients Based on Stage of Change at an Urban Primary Care Clinic

Background: Obesity screening and behavioral counseling for adults is recommended but rarely feasible to reduce the risk of developing cancer and many chronic diseases. We intiated obesity screening at an urban clinic and offered obese patients tailored counseling using PACE+, a validated tool designed for the primary care setting.

Aim: To evaluate obesity screening rates, readiness to change, preferences for change and change in BMI in patients counseled with PACE+.

Methods: Electronic medical record (EMR) review of patient data from May 2006 to March 2008. Analyses comparing stage of change to patient characteristics was conducted using the Cochran-Armitage Trend Test. Bivariate comparisons of the continuous items were analyzed using the Chi-square.

Results: Of 5,390 patients in the clinic practice, 2532 (47%) were obese, 2269 (42%) were normal or overweight, and 589 (11%) were not screened. PACE+ educators counseled 843 obese patients (33%) May 2006-March 2008. Mean age 50, mean BMI 39, 79% female and 98% African American. 31% of PACE+ participants had hypertension, diabetes mellitus and hyperlipidemia. Stage of change for exercise was most often contemplation (38%) and preparation (40%). The preferred activity was walking (62%). Most cited reasons to change behavior were to lower blood pressure, improve health, reduce weight, and increase energy. Most reported activity barriers were pain (20%), weather (13%), and time (10%). Most patients rated their stage of change for reducing calories as preparation (62%). Anticipated nutrition adherence barriers were “will-power,” cost, and time. Participants rated their self-confidence for activity and dietary changes highly. A trend to weight stabilization and weight loss was observed with follow-up.

Conclusion: Obesity screening and a structured low-intensity behavioral counseling by educators was feasible and reached 33% of obese patients in the practice. PACE+ evaluation in the EMR provides retrievable and measurable information about patient stage of change, preferences and perceived adherence barriers. This data can direct efforts to link community and personal resources to optimize behavioral and weight outcomes. Pain cited as an activity barrier by 20% needs further study.

High efficiency thin-film crystalline Si/Ge tandem solar cell

We propose and simulate a photovoltaic solar cell comprised of Si and Ge pn junctions in tandem. With an anti-reflection film at the front surface, we have shown that optimal solar cells favor a thin Si layer and a thick Ge layer with a thin tunnel hetero-diode placed in between. We predict efficiency ranging from 19% to 28% for AM1.5G solar irradiance concentrated from 1 approximately 1000 Suns for a cell with a total thickness approximately 100 microm.

Variation explained in mixed-model association mapping

Genomic mapping of complex traits across species demands integrating genetics and statistics. In particular, because it is easily interpreted, the R(2) statistic is commonly used in quantitative trait locus (QTL) mapping studies to measure the proportion of phenotypic variation explained by molecular markers. Mixed models with random polygenic effects have been used in complex trait dissection in different species. However, unlike fixed linear regression models, linear mixed models have no well-established R(2) statistic for assessing goodness-of-fit and prediction power. Our objectives were to assess the performance of several R(2)-like statistics for a linear mixed model in association mapping and to identify any such statistic that measures model-data agreement and provides an intuitive indication of QTL effect. Our results showed that the likelihood-ratio-based R(2) (R(LR)(2)) satisfies several critical requirements proposed for the R(2)-like statistic. As R(LR)(2) reduces to the regular R(2) for fixed models without random effects other than residual, it provides a general measure for the effect of QTL in mixed-model association mapping. Moreover, we found that R(LR)(2) can help explain the overlap between overall population structure modeled as fixed effects and relative kinship modeled though random effects. As both approaches are derived from molecular marker information and are not mutually exclusive, comparing R(LR)(2) values from different models provides a logical bridge between statistical analysis and underlying genetics of complex traits.

The relationship between Chinese construction workers' HIV/AIDS-related knowledge, attitudes and behaviour: a structural equation model

This study explored the relationship between human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS)-related knowledge, attitudes and behaviour in migrant urban construction workers using structural equation modelling (SEM). A cross-sectional study was conducted among 428 male subjects on three building sites in Shenyang City. The SEM model of HIV/AIDS-related knowledge, attitudes and behaviour was built using LISREL version 8.5 and it fitted the data well, as shown by an adjusted goodness of fit index of 0.82 and a root mean square error of approximation of 0.094. Knowledge of HIV/AIDS was closely correlated with attitudes and behaviour. Age was an important factor affecting HIV/AIDS-related knowledge, attitudes and behaviour. These findings suggest that increasing HIV/AIDS-related knowledge could improve the attitude and behaviour of migrant urban construction workers, enabling them to avoid high-risk behaviour that increases the spread of HIV/AIDS. Any intervention used will need to take the important factor of age into consideration.

Reliability and validity testing of the SF-36 questionnaire for the evaluation of the quality of life of Chinese urban construction workers

The quality of life (QOL) of the Chinese 'floating' migrant population is of growing concern. Urban construction workers are the main migrant population in China, but there is little published research on their QOL. The reliability and validity of the 36-Item Short Form Health Survey (SF-36) questionnaire were assessed by conducting a population-based study of migrant construction workers in Shenyang, China. Two construction sites were randomly selected from each of the five districts of Shenyang City and 1200 copies of the questionnaire were distributed to rurally-registered, non-Shenyang workers aged > or = 16 years at these sites. A total of 1125 questionnaires were evaluated. The overall Cronbach's alpha coefficient of the SF-36 questionnaire was 0.821 while the respective Cronbach's alpha coefficient for each dimension was > 0.70. Results showed that the SF-36 questionnaire demonstrated good reliability and validity, and that it can be used to measure QOL among Chinese migrant urban construction workers.

Evaluation of the association of CXCR4 expression with HER2 status or mTOR expression levels

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Introduction: CXCR4 is a chemokine receptor that is linked to breast cancer metastasis. The putative mechanism involves activation of the HER-2/PI3K/PTEN/Akt/mammalian target of rapamycin (mTOR) pathway, resulting in enhanced synthesis of downstream proteins such as CXCR4 and eukaryotic initiation factor 4E (eIF4E). Overexpression of eIF4E has been shown to be an independent predictor of breast cancer outcome. Because HER-2/mTOR/CXCR4 pathway has mainly been observed in vitro, it deserves scrutiny to determine whether it is also seen in human breast cancers. We hypothesize that HER-2/mTOR axis is not significantly associated with CXCR4 regulation in human breast cancers. Method: 107 stages 1 - 3 breast cancers from a prospective breast cancer database were analyzed. Samples were quantified for mTOR, CXCR4, and eIF4E levels by Western Blot. mTOR, and eIF4E levels were quantified as fold-over benign breast tissues and CXCR4 levels were quantified as fold-over Hela cells. CXCR4 overexpression was defined as low (< 6.0 fold) or high (≥ 6.0 fold), and eIF4E expression level was separated into tertiles. Primary end points were cancer recurrence and death. Statistical analyses performed were independent student t-test, Spearman correlation, Kaplan-Meier survival curves, log-rank test, and Cox proportional hazard model. Results: All 59 HER-2 (-) and 48 HER-2 (+) breast cancer specimens overexpressed CXCR4 (mean=6.18 ±4.4), mTOR (mean=1.24 ±1.58), and eIF4E (mean=9.53 ±6.42). Unlike in vitro data, there was no difference in mean CXCR4 expression level between HER-2 (-) and HER-2 (+) tumors (mean=6.55, 5.72, respectively) (p=0.33). While mTOR correlated significantly with eIF4E level (p=0.0006, r = 0.34), it did not correlate with CXCR4 level (p=0.713, r=0.036). Only nodal status (p=0.04) and eIF4E level (p=0.03) were independent predictors of breast cancer death. Conclusions: We demonstrate that CXCR4 regulation in human breast cancers is more complex than previously thought. There was no correlation between mTOR and CXCR4 levels, nor was there a difference in mean CXCR4 overexpression levels between HER-2 (+) and HER-2 (-) tumors. Pathways regulating CXCR4 expression warrant further investigation.

No significant financial relationships to disclose.

QTL analyses of seed weight during the development of soybean (Glycine max L. Merr.)

At harvest traits such as seed weight are the sum of development and responses to stresses over the growing season and particularly during the reproductive phase of growth. The aim here was to measure quantitative trait loci (QTL) underlying the seed weight from early development to drying post harvest. One hundred forty-three F(5) derived recombinant inbred lines (RILs) developed from the cross of soybean cultivars 'Charleston' and 'Dongnong 594' were used for the analysis of QTL underlying mean 100-seed weight at six different developmental stages. QTL x Environment interactions (QE) were analyzed by a mixed genetic mode based on 3 years' data. At an experiment-wise threshold of a=0.05 and by single-point analysis 94 QTL unaffected by QE underlay the mean seed weight at different developmental stages. Sixty-eight QTL affected by QE that also underlay mean seed weight were identified. From the 162 QTL 42 could be located on 12 linkage groups by composite interval mapping (LOD>2.0). The numbers, locations and types of the QTL and the genetic effects were different at each developmental stage. On linkage group C2 the distantly linked QTL swC2-1, swC2-2 and swC2-3 each affected mean seed weight throughout the different developmental stages. The DNA markers linked to the QTL possessed potential for use in marker-assisted selection for soybean seed size. The identification of QTL with genetic main effects and QE interaction effects suggested that such interactions might significantly alter seed weight during seed development.

RNA interference-mediated silencing of the polo-like kinase 1 gene enhances chemosensitivity to gemcitabine in pancreatic adenocarcinoma cells

Gemcitabine is the first-line chemotherapeutic agent for advanced adenocarcinoma of the pancreas; however, chemoresistance to gemcitabine remains a major cause of failure for the clinical treatment of this disease. Polo-like kinase 1 (Plk-1) is highly expressed in pancreatic cancer cell lines and pancreatic tumour tissues, and is involved in a wide variety of cell cycle processes. Nevertheless, its biological role and implication for gemcitabine resistance are not clearly defined. In this study, we used RNA-interference (RNAi)-mediated depletion of Plk-1 to determine its potential for sensitizing pancreatic tumour cells to gemcitabine. We showed that the level of Plk-1 protein was correlated significantly with gemcitabine resistance in human pancreatic adenocarcinoma cells and that overexpression of Plk-1 reduced sensitivity to gemcitabine in these cells. In addition, small interfering RNA (siRNA)-mediated knockdown of Plk-1 caused cell cycle arrest at G2/M and the reduction of cellular proliferation. More importantly, the treatment of pancreatic cancer cells with Plk-1 siRNA followed by exposure to gemcitabine dramatically decreased cell viability and increased cellular apoptosis, as compared with treatment with either agent alone. These observations indicate that down-regulation of Plk-1 expression by RNAi enhances gemcitabine sensitivity and increases gemcitabine cytotoxicity in pancreatic tumour cells. This is the first demonstration that the combination of Plk-1 gene therapy and gemcitabine chemotherapy has synergistic anti-tumour activity against pancreatic carcinoma in vitro. This combination treatment warrants further investigation as an effective therapeutic regimen for patients with resistant pancreatic cancer and other tumours.

A statistical analysis on the removal of organic matter in subsurface flow constructed wetlands in the U.K

The performances of 98 subsurface flow constructed wetlands in the U.K. are analysed for the rates of organic matter removal from various wastewaters. The analyses of 78 subsurface horizontal flow wetlands are focused on deriving the value of rate constant K(BOD) in the Kickuth equation and evaluating the probability of meeting the target when the equation is used in design. The analyses of 20 vertical flow wetlands are focused on establishing the correlations between BOD (biochemical oxygen demand) removal rate and organic loading; an empirical relation has been developed to estimate the surface areas of the wetlands.

Thin-trimming of the scrotal reconstruction flap: long-term follow-up shows reversal of spermatogenesis arrest

OBJECTIVE

To explore a method to decrease the arrest of spermatogenesis in patients undergoing scrotum reconstruction with a flap.

METHODS

A follow-up study on a patient whose scrotum had been reconstructed with a flap revealed the arrest of spermatogenesis. The flap was trimmed thin on two occasions, and the composition of the seminal fluid was followed up.

RESULTS

The follow-up showed a decrease in the arrest of spermatogenesis after the flap was thin-trimmed.

CONCLUSIONS

Thin-trimming the reconstruction flap can decrease the degree of spermatogenesis arrest in patients who have received scrotum reconstruction by thick flap.

Interaction of folliculin (Birt-Hogg-Dubé gene product) with a novel Fnip1-like (FnipL/Fnip2) protein

Birt-Hogg-Dubé (BHD) syndrome is characterized by the development of pneumothorax, hair folliculomas and renal tumors and the responsible BHD gene is thought to be a tumor suppressor. The function of folliculin (Flcn), encoded by BHD, is totally unknown, although its interaction with Fnip1 has been reported. In this study, we identified a novel protein binding to Flcn, which is highly homologous to Fnip1, and which we named FnipL (recently reported in an independent study as Fnip2). The interaction between FnipL/Fnip2 and Flcn may be mediated mainly by the C-terminal domains of each protein as is the case for the Flcn-Fnip1 interaction. FnipL/Fnip2 and Flcn were located together in the cytoplasm in a reticular pattern, although solely expressed Flcn was found mainly in the nucleus. Cytoplasmic retention of Flcn was canceled with C-terminal truncation of FnipL/Fnip2, suggesting that FnipL/Fnip2 regulates Flcn distribution through their complex formation. By the employment of siRNA, we observed a decrease in S6K1 phosphorylation in the BHD-suppressed cell. We also observed a decrease in S6K1 phosphorylation in FNIP1- and, to a lesser extent, in FNIPL/FNIP2-suppressed cells. These results suggest that Flcn-FnipL/Fnip2 and Flcn-Fnip1 complexes positively regulate S6K1 phosphorylation and that FnipL/Fnip2 provides an important clue to elucidating the function of Flcn and the pathogenesis of BHD.

A whole genome linkage scan identifies multiple chromosomal regions influencing adiposity-related traits among Samoans

We conducted a genome-wide scan in 46 pedigrees, with 671 phenotyped adults, from the independent nation of Samoa to map quantitative trait loci (QTLs) for adiposity-related phenotypes, including body mass index (BMI), abdominal circumference (ABDCIR), percent body fat (%BFAT), and fasting serum leptin and adiponectin. A set of 378 autosomal and 14 X chromosomal microsatellite markers were genotyped in 572 of the adults. Significant genetic correlations (0.82-0.96) were detected between pairs of BMI, ABDCIR, %BFAT and leptin. Suggestive linkages were found on 13q31 (LOD = 2.30 for leptin, LOD = 2.48 for %BFAT, LOD = 2.04 for ABDCIR, and LOD = 2.09 for BMI) and on 9p22 (LOD = 3.08 for ABDCIR and LOD = 2.53 for %BFAT). Furthermore, bivariate linkage analyses indicated that the genetic regions on 9p22 (bivariate LOD 2.35-3.10, LOD(eq) (1df) 1.88-2.59) and 13q31 (bivariate LOD 1.96-2.64, LOD(eq) 1.52-2.21) might harbor common major genes with pleiotropic effects. Other regions showing suggestive linkage included 4q22 (LOD = 2.95) and 7p14 (LOD = 2.64) for %BFAT, 2q13 for adiponectin (LOD = 2.05) and 19q12 for BMI-adjusted leptin (LOD = 2.03). Further fine mapping of these regions may help identify the genetic variants contributing to the development of obesity in Samoan adults.

Chiari malformation caused by craniometaphyseal dysplasia: case report and review of literature

Chiari malformation is commonly considered a congenital condition. To our knowledge, reports of progressively symptomatic Chiari Iota malformation with craniometaphyseal dysplasia are rare. The authors present a case of progressively symptomatic Chiari Iota malformation occurring in an 11-month-old infant with craniometaphyseal dysplasia. The patient presented with a typical facial appearance and radiological skeletal survey. Posterior fossa decompression was performed. In the meantime, the patient was given Rocaltrol (calcitriol) and adopted a low calcium diet. His neurological symptoms were markedly improved after surgery. The clinical presentations, radiographical features and prognosis of the patient are discussed with reference to the literature.

A guanylyl cyclase-like gene is associated with Gibberella ear rot resistance in maize (Zea mays L.)

Gibberella ear rot, caused by the fungal pathogen Fusarium graminearum Schwabe, is a serious disease of maize (Zea mays L.) grown in northern climates. The infected maize grain contains toxins that are very harmful to livestock and humans. A maize gene that encodes a putative 267-amino acid guanylyl cyclase-like protein (ZmGC1) was characterized and shown to be associated with resistance to this disease. The putative ZmGC1 amino acid sequence is 53% identical and 65% similar to AtGC1, an Arabidopsis guanylyl cyclase. The Zmgc1 coding sequence is nearly identical in a Gibberella ear rot-resistant line (CO387) and a susceptible line (CG62) but several nucleotide sequence differences were observed in the UTRs and introns of the two alleles. Using a 463 bp probe derived from the CG62 allele of Zmgc1 and a recombinant inbred (RI) mapping population developed from a CG62 x CO387 cross, six Zmgc1 restriction fragment length polymorphism (RFLP) fragments (ER1_1, ER1_2, ER1_3, ER1_4, ER1_5, and ER5_1) were mapped on maize chromosomes 2, 3, 7, and 8. Markers ER1_1 and ER5_1 on chromosomes 7 and 8, respectively, were significantly associated with Gibberella ear rot resistance, each in three different environments. The amount of Zmgc1 transcript in ear tissues increased more quickly and to a greater extent in the resistant genotype compared to the susceptible genotype after inoculation with F. graminearum. Zmgc1 is the first guanylyl cyclase gene characterized in maize and the first gene found to be associated with Gibberella ear rot resistance in this plant.

First Report of Five Sooty Blotch and Flyspeck Fungi on Prunus americana in the United States

The sooty blotch and flyspeck (SBFS) complex includes more than 30 fungi that blemish the cuticle of apple fruit, causing economic losses in humid regions worldwide (1). In August 2005, we sampled SBFS-infested wild plum (Prunus americana) fruit growing in hedgerows in Iowa. Colonies were categorized according to mycelial type (1), and isolates were made from representative colonies onto acidified water agar (AWA). Plum skins with SBFS signs were excised, pressed, and photographed. DNA was obtained from purified isolates and also from mycelium and fruiting bodies scraped directly from plum fruit skins. Extracted DNA was amplified using primer pair ITS1-F/Myc1-R (ACTCGTCGAAGGAGCTACG) and PCR products were sequenced using primer pair ITS-1F/ITS4. Six sequences were obtained from pure cultures and seven from colonies on plum fruit skin. BLAST analysis of the 470-bp sequences showed 100% homology to five known species in the SBFS complex: Zygophiala cryptogama, Zygophiala wisconsinensis, Pseudocercosporella sp. RH1, and Stomiopeltis spp. RS1 and RS2 (GenBank Accession Nos. AY598854, AY598853, AY5988645, AY598882, and AY598883, respectively). Observations of colony and fruiting structure morphology from cultures on potato dextrose agar (PDA) and colonies on plums confirmed species identity. A modified version of Koch's postulates was conducted to verify that these fungi caused the signs observed on plum and could also infest apple fruit. In June 2006, 1-month-old cultures on PDA were pulverized in a blender with sterile distilled water, passed through four layers of sterile cheesecloth, and transferred to sterile jars. Each isolate was inoculated onto 20 fruit on plum trees (P. americana) on the Iowa State University (ISU) campus and 20 fruit on cv. Golden Delicious apple trees at the ISU Research Station, Gilbert, IA. Each fruit was disinfested with 70% ethanol, air dried, swabbed with inoculum, and covered with a Fuji bag. At harvest, fungal colonies on fruit were reisolated onto AWA. DNA was extracted from pure cultures; when isolations on agar were unsuccessful, DNA was extracted directly from colonies on fruit. PCR was conducted using ITS1-F/Myc1-R, and PCR products were sequenced using ITS1-F/ITS4. All five species were reisolated and sequenced from apple. Pseudocercosporella sp. RH1 and Stomiopeltis sp. RS1 were sequenced from inoculated plums. Although flyspeck, presumably caused by Schizothyrium pomi, was reported on Japanese plum (P. salicina) in Japan (2) and black cherry (P. serotina) in the United States (3), to our knowledge this is the first report of SBFS fungi on plum in the United States and the first confirmation that fungi from plum can produce SBFS signs on apple fruit. Wild plum may therefore act as a reservoir host, providing inoculum for SBFS infestations on apple. References: (1) J. Batzer et al. Mycologia 97:1268, 2005. (2) H. Nasu and H. Kunoh. Plant Dis. 71:361, 1987. (3) T. B. Sutton. Plant Dis. 72:801, 1988.