MGr1-Ag/37LRP promotes growth and proliferation of gastric cancer in vitro and in vivo

Gastric carcinoma (GC) is an aggressive cancer with a poor prognosis. We previously reported that MGr1-Ag was involved in multidrug resistance and anti-apoptosis in GC. However, the exact function of MGr1-Ag in GC proliferation is not clear. In this study, we found that MGr1-Ag was highly expressed in GC tissues and four GC cell lines compared with nontumor gastric tissues or gastric epithelial mucosa cells. The high expression of MGr1-Ag/37LRP was also consistent with the decreased median survival time of GC patients. We employed lenti-mediated RNA interference technique to knock down MGr1-Ag expression in SGC7901 and MKN45 cells, respectively, and observed its effects on GC cells growth in vitro and in vivo. Further study showed that knockdown of MGr1-Ag could inhibit GC cell proliferation by inhibiting the cell cycle S-phase entry and induced apoptosis. Soft agar colony formation assay indicated that the colony formation ability of SGC7901 and MKN45 cells decreased after lenti-MGr1-Ag small interfering RNA (siRNA) infection. Western blot revealed that cyclin D1 and Bcl-2 expression were downregulated whereas p27 and Bax were upregulated in lenti-MGr-siRNA-infected GC cells. Further study demonstrated that the proliferation effect of MGr1-Ag in GC is dependent on its laminin-binding region. Taken together, these data revealed a novel function of MGr1-Ag that can possibly be used as an independent prognostic factor and a potential therapeutic target for GC.

Randomised clinical trial: L-ornithine-L-aspartate reduces significantly the increase of venous ammonia concentration after TIPSS

BACKGROUND

Use of TIPSS is associated with increases in ammonia concentration and hepatic encephalopathy (HE) risk. L-ornithine-L-aspartate (LOLA) is effective in reducing ammonia concentration.

AIM

To evaluate the effects of LOLA on venous ammonia concentration after TIPSS.

METHODS

The included patients were randomised to receive LOLA or no-LOLA treatment for 7 days. Fasting and post-prandial venous ammonia levels were the primary outcomes. Psychometric performance, post-TIPSS HE, and liver and renal function were assessed as secondary outcomes.

RESULTS

Of 133 cirrhotic patients who received successful TIPSS between November 2011 and June 2012, 40 met the inclusion criteria and were randomised to the LOLA (n = 21) or control (n = 19) groups. Change in fasting ammonia significantly favoured the LOLA group at days 4 (P = 0.001) and 7 (P = 0.003). Changes in post-prandial ammonia concentration significantly favoured the LOLA group at days 1, 4 and 7 as well. During the study period, patients in the LOLA group had better improvement in psychometric tests than those in the control group. Overt HE during treatment was observed in one patient in the LOLA group and three patients in the control group (P = 0.331). There were no differences in complications, adverse events or mortality between the two groups.

CONCLUSIONS

Prophylactic use of LOLA infusion after TIPSS is safe and effective in significantly reducing the increase of venous ammonia concentration, and can benefit the patient's mental status as well.

Systematic review: faecal microbiota transplantation therapy for digestive and nondigestive disorders in adults and children

BACKGROUND

There has been growing interest in the use of faecal microbiota transplantation (FMT) for the treatment of gastrointestinal and nongastrointestinal diseases.

AIM

To review systematically the reported efficacy and safety of FMT in the management of gastrointestinal and nongastrointestinal disorders in adults and children.

METHODS

The systematic review followed Cochrane and PRISMA recommendations. Available articles were identified using three electronic databases in addition to hand searching and contacting experts. Inclusion criteria were any reports of FMT therapy written in English.

RESULTS

A total of 844 patients who had undergone FMT were identified from 67 published studies. The most common indications were refractory/relapsing Clostridium difficile infection (CDI) (76.3%) and inflammatory bowel disease (IBD) (13.2%). There has been only one placebo-controlled trial, a successful trial in 43 patients with recurrent CDI. Seven publications report FMT in paediatric patients with a total of 11 treated, 3 with chronic constipation and the remainder with recurrent CDI or ulcerative colitis (UC). 90.7% of patients with refractory/relapsing CDI were cured and 78.4% of patients with IBD were in remission after FMT. FMT therapy could also be effective in treatment of some nongastrointestinal disorders such as chronic fatigue syndrome. The only reported serious adverse event attributed to the therapy was a case of suspected peritonitis.

CONCLUSIONS

Although more controlled trials are needed, faecal microbiota transplantation therapy shows promise in both adults and children with gastrointestinal diseases such as CDI and IBD.

Sorafenib dose escalation is not uniformly associated with blood pressure elevations in normotensive patients with advanced malignancies

Hypertension with vascular endothelial growth factor (VEGF) receptor inhibitors is associated with superior treatment outcomes for advanced cancer patients. To determine whether increased doses of sorafenib cause incremental increases in blood pressure (BP) we measured 12-hour ambulatory BP in 41 normotensive advanced solid tumor patients in a randomized dose escalation study. After 7 days’ sorafenib (400mg BID) mean diastolic BP (DBP) increased in both study groups. After dose escalation, group A (400mg TID) had marginally significant further increase in 12-hour mean DBP (p=0.053) but group B (600mg BID) did not achieve statistically significant increases (p=0.25). Within groups, individuals varied in BP response to sorafenib dose escalation, but these differences did not correlate with changes in steady state plasma sorafenib concentrations. These findings in normotensive patients suggest BP is a complex pharmacodynamic biomarker of VEGF inhibition. Patients have intrinsic differences in sensitivity to the BP elevating effects of sorafenib.

Abstract P4-07-05: Cyclin D1 induction of dicer governs microRNA processing and expression in breast cancer

MicroRNAs (miRNAs), a class of non-coding small RNA, regulate gene expression through base-pairing binding to the complementary sequence in the 3’ untranslated region (3’ UTR) of mRNA. miRNAs contribute to the timing of development, apoptosis, cell cycle progression, cellular proliferation, stem cell self-renewal, cancer initiation and metastasis. The expression of miRNA is regulated during cell-cycle transition and cellular contact in part via active degradation. Aberrant expression of miRNAs or mutations of miRNA genes have been described in many types of tumors, including mammary tumors. The RNase III endoribonuclease Dicer cleaves long double-stranded RNA (dsRNA) or stem-loop-stem structured pre-miRNA to form mature miRNAs. RNAi-mediated knock-down of Dicer in human cells led to defects in both miRNA production and shRNA-mediated RNAi.

Initially cloned as a breakpoint rearrangement in parathyroid adenoma, the cyclin D1 gene encodes the regulatory subunit of the holoenzyme that phosphorylates and inactivates both the pRb tumor suppressor and the key inducer of mitochondrial biogenesis NRF-1. In addition, a DNA bound form of cyclin D1 regulates gene expression. Cyclin D1 expression is induced during mammary gland and retinal differentiation, and deletion of the murine cyclin D1 gene resulted in failed terminal alveolar breast bud development and retinal degeneration. Diverse biological functions regulated by cyclin D1 include the induction of cellular proliferation, angiogenesis, cellular migration, DNA damage repair, mitochondrial biogenesis, stem cell maintenance, and miRNA expression. Cyclin D1 was shown to regulate the miR-17/20 locus and found to bind the miR-17/20 regulatory region.

In order to determine further the mechanism by which cyclin D1 regulates non-coding RNA, we conducted studies of miRNA processing. We established cyclin D1-/- mouse embryonic fibroblasts cells (MEFs) and cyclin D1 knockdown (KD) MCF-7 human breast cancer cells. miRNA analysis indicated an induction of mature miRNA expression in cyclin D1 overexpressing cells. Analysis of the miRNA processing regulators demonstrated the selective induction of Dicer expression by cyclin D1. In cyclin D1-/- cells the reduction of Dicer abundance was accompanied by impairment of pre-miRNA to mature miRNA processing, which was restored with cyclin D1 rescue. Transient transgenic expression of cyclin D1 in the mouse mammary gland, or sustained transgenic expression of cyclin D1 induced mouse mammary gland tumors, recapitulated the induction of Dicer expression. Cyclin D1 and Dicer expression were correlated in luminal A and basal-like human breast cancer. Cyclin D1 regulation of cellular proliferation and migration was dependent upon Dicer. By demonstrating cyclin D1 induced Dicer abundance and function in tissue culture and in vivo, we provide evidence for novel crosstalk between the cell-cycle and non-coding miRNA biogenesis.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-07-05.

Abstract P1-07-05: The cell fate factor DACH1 represses YB-1-mediated oncogenic transcription and translation

The epithelial-mesenchymal transition (EMT) enhances cellular invasiveness and confers tumor cells with cancer stem cell like characteristics, through transcriptional and translational mechanisms. The mechanisms maintaining transcriptional and translational repression of EMT and cellular invasion are poorly understood. The Drosophila homologue of DACH1, the Dac gene is a key member of the retinal determination gene network that specifies organismal development. The dachshund (dac), eya1, eyes-absent (eya), twin of eyeless (toy), teashirt (tsh) and sinoculues (so) are expressed in progenitor cells, contributing to development of the eye and genitalia. Loss of DACH1 expression contributes to the expansion of neural progenitors, muscle satellite cell differentiation and breast cancer stem cells. In recent studies Dachshund repressed breast cancer stem cell expansion. DACH1 expression is reduced in a variety of human cancers including prostate, ovarian and human breast cancer.

Herein, the cell fate-determination factor Dachshund (DACH1), suppressed EMT via repression of cytoplasmic translational induction of Snail by inactivating the Y box-binding protein (YB-1). In the nucleus, DACH1 antagonized YB-1-mediated oncogenic transcriptional modules governing cell invasion. DACH1 blocked YB-1-induced mammary tumor growth and EMT in mice. In basal-like breast cancer (BLBC) the reduced expression of DACH1 and increased YB-1, correlated with poor metastasis free survival. The loss of DACH1 suppression of both cytoplasmic translational and nuclear transcriptional events governing EMT and tumor invasion may contribute to poor prognosis in BLBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-05.

Abstract P5-11-04: Post-translational modification of the cell-fate factor Dachshund determines p53 binding and signaling modules in breast cancer

Breast cancer is a leading form of cancer in the world. Initially cloned as a dominant inhibitor of the hyperactive EGFR, Ellipse, in Drosophila, the mammalian DACH1 regulates expression of target genes in part through interacting with DNA-binding transcription factors (c-Jun, Smads, Six, ERα), and in part through intrinsic DNA-sequence specific binding to Forkhead binding sites. The Drosophila dac gene is a key member of the retinal determination gene network (RDGN), which also includes eyes absent (eya), ey, twin of eyeless (toy), teashirt (tsh) and sin oculis (so), that specifies eye tissue identity.

Several lines of evidence suggest DACH1 may function as a tumor suppressor. Clinical studies have demonstrated a correlation between poor prognosis and reduced expression of the cell-fate determination factor DACH1 in breast cancer, and loss of DACH1 expression has been observed in prostate and endometrial cancer. DACH1 inhibits breast cancer tumor metastasis and reduces breast cancer stem cell expansion via Sox2/Nanog. Although these studies suggest DACH1 may function as a tumor suppressor, the molecular mechanisms remain poorly defined. Herein, endogenous DACH1 co-localized with p53 in a nuclear, extranucleolar compartment and bound to p53 in human breast cancer cell lines, p53 and DACH1 bound common genes in ChIP-Seq. Full inhibition of breast cancer contact-independent growth by DACH1 required p53. The p53 breast cancer mutants R248Q and R273H, evaded DACH1 binding. DACH1 phosphorylation at serine residue (S439) inhibited p53 binding and phosphorylation at p53 amino-terminal sites (S15, S20) enhanced DACH1 binding. DACH1 binding to p53 was inhibited by NAD-dependent deacetylation via DACH1 K628. DACH1 repressed p21CIP1 and induced RAD51, an association found in basal breast cancer. DACH1 inhibits breast cancer cellular growth in an NAD and p53 dependent manner through direct protein-protein association.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-11-04.

Abstract P3-02-03: The phosphatase function of the eyes absent (EYA) homolog is required for the induction of breast cancer cellular proliferation via cyclin D1

The Drosophila Eyes Absent Homologue 1 (EYA1) is a component of the retinal determination gene network (RDGN) and serves as an H2AX phosphatase. The cell fate determination gene network includes the dachshund (dac), twin-of-eyeless (toy), eye absent (eya), teashirt (tsh) and sine oculis (So). In Drosophila, mutations of the RDGN leads to failure of eye formation, whereas, forced expression induces ectopic eye formation. EYA functions as a transcriptional co-activator being recruited in the context of local chromatin, but lacking intrinsic DNA binding activity. EYA family members EYA 1-4 are defined by a 275 amino acid carboxyl-terminal motif that is conserved between species, referred to as the EYA domain (ED). The human homologs EYA 1-4 are highly conserved in their EYA domain and amino termini, with the exception of a small tyrosine rich residue region named EYA domain II.

Altered expression or functional activity of the RDGN has been documented in a variety of malignancies. DACH1 expression is reduced in breast, prostate, endometrial and brain cancer. EYA2 is up regulated in ovarian cancer, promoting tumor growth. EYA1 and EYA2 enhanced survival in response to DNA damage producing agents in HEK293 cells. Eya2 was required for Six1/TGFb signals that govern a prometastatic phenotype and epithelial mesenchymal transition (EMT). Although EYA proteins are expressed in human breast cancer, the relationship to molecular genetic subtype, prognosis and the molecular mechanisms governing contact-independent growth are not known.

The cyclin D1 gene encodes the regulatory subunits of a holoenzyme that phosphorylates and inactivates the pRb protein. Herein, comparison with normal breast demonstrated EYA1 is overexpressed with cyclin D1 in luminal B breast cancer subtype. EYA1 enhanced breast tumor growth in mice in vivo requiring the phosphatase domain. EYA1 enhanced cellular proliferation, inhibited apoptosis, and induced contact-independent growth and cyclin D1 abundance. The induction of cellular proliferation and cyclin D1 abundance, but not apoptosis, was dependent upon the EYA1 phosphatase domain. The EYA1-mediated transcriptional induction of cyclin D1 occurred via the AP-1 binding site at -953 and required the EYA1 phosphatase function. The AP-1 mutation did not affect SIX1-dependent activation of cyclin D1. EYA1 was recruited in the context of local chromatin to the cyclin D1 AP-1 site. The EYA1 phosphatase function determined the recruitment of CBP, RNA polymerase II and acetylation of H3K9 at the cyclin D1 gene AP-1 site regulatory region in the context of local chromatin. The EYA1 phosphatase regulates cell cycle control via transcriptional complex formation at the cyclin D1 promoter.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-02-03.

Long-term use of multivitamins and risk of colorectal adenoma in women

Background:

Use of multivitamins may reduce the risk of colorectal adenoma, but the duration of use needed is unclear.

Methods:

We prospectively examined years of multivitamin use and risk of colorectal adenoma among 43 641 women who had a first endoscopy between 1991 and 2007 in the Nurses' Health Study II. Use of multivitamins was assessed through biennial questionnaires since 1989.

Results:

We documented 2277 colorectal adenoma cases. Reporting multivitamin use at any time during the study period compared with never reporting its use was associated with a reduced risk of adenoma (multivariable relative risk (RR)=0.86, 95% confidence interval (CI): 0.76–0.97). There was no clear trend with duration of multivitamin use: years of use compared with never use, ⩽4 years (RR=0.84, 95% CI: 0.74–0.96), 5–9 years (RR=0.89, 95% CI: 0.77, 1.02), 10–14 years (RR=0.86, 95% CI: 0.74, 1.01), 15–19 years (RR=0.85, 95% CI: 0.70, 1.02), and 20–26 years (RR=0.80, 95% CI: 0.64, 1.01); (P trend=0.87). The strongest associations (years of use vs never user) were for size of adenoma: large (⩾1 cm) <4 years (RR=0.75, 95% CI: 0.58–0.96) and in alcohol users (⩾1.4 g per day) 20–26 years (RR=0.67, 95% CI: 0.49–0.91).

Conclusion:

Our findings suggest that use of multivitamins is associated with lower risk of colorectal adenoma, even with relatively short duration of use.

Predictive performance of reported population pharmacokinetic models of vancomycin in Chinese adult patients

WHAT IS KNOWN AND OBJECTIVE

There are numerous studies on population pharmacokinetics of vancomycin in adult patients. However, there is no such research for Chinese adult patients. This study was conducted to evaluate the predictive performance of reported population pharmacokinetic models of vancomycin in Chinese adult patients and to identify some models appropriate for our population.

METHODS

A literature search was conducted in PubMed to obtain the population pharmacokinetic models of vancomycin published between December 2010 and September 2012. The models were assessed using concentration data collected from Chinese patients for external validation. Models with relatively poor predictability were excluded from further analysis. The performance of the remaining models was evaluated in patients with different levels of creatinine clearance, age, body weight and sex by Bayesian method. This method was also used to compare the predictive performance based on peak concentration and trough concentration and the predictability based on different number of observed concentrations.

RESULTS

One hundred and sixty-five blood concentrations from 72 Chinese adult patients were collected retrospectively to serve as the test data set. The evaluated models included all those reported in the seven publications reviewed by Marsot et al. and three other studies published after December 2010. Three models with poor performance on external validation were excluded from the next Bayesian analysis. The distribution of covariates in the model building data set had an important effect on prediction. The predictability based on peak/trough concentration was similar among the evaluated models, and no significant difference was found using our data set except for Roberts' model. As expected, an increased number of samples improved the performance of the Bayesian prediction.

WHAT IS NEW AND CONCLUSION

With our data set, the performance of the evaluated models varied. The characteristics of the patient population and distribution of covariates should be given more consideration when choosing a model to predict blood concentrations. The model developed by Purwonugroho et al. using a data set from patients similar to ours is appropriate for Bayesian dose predictions for vancomycin concentrations in our population of Chinese adult patients.

Loss of cell adhesion molecule CHL1 improves homeostatic adaptation and survival in hypoxic stress

Close homologue of L1 (CHL1) is a transmembrane cell adhesion molecule that is critical for brain development and for the maintenance of neural circuits in adults. Recent studies revealed that CHL1 has diverse roles and is involved in the regulation of recovery after spinal cord injury. CHL1 expression was downregulated in the cerebral cortex, hypothalamus, and brain stem after the induction of acute hypoxia (AH). In the current study, we sought to address the role of CHL1 in regulating homeostasis responses to hypoxia using CHL1-knockout (CHL1^−/−) mice. We found that, compared with wild-type littermates, CHL1^−/− mice showed a dramatically lower mortality rate and an augmented ventilatory response after they were subjected to AH. Immunofluorescence staining revealed that CHL1 was expressed in the carotid body (CB), the key oxygen sensor in rodents, and CHL1 expression level in the CB as assayed by western blot was decreased after hypoxic exposure. The number of glomus cells and the expression of tyrosine hydroxylase (a marker for glomus cells) in the CB of CHL1^−/− mice appeared to be increased compared with CHL1^+/+ mice. In addition, in the ex vivo CB preparation, hypoxia induced a significantly greater afferent nerve discharge in CHL1^−/− mice compared with CHL1^+/+ mice. Furthermore, the arterial blood pressure and plasma catecholamine levels of CHL1^−/− mice were also significantly higher than those of CHL1^+/+ mice. Our findings first demonstrate that CHL1 is a novel intrinsic factor that is involved in CB function and in the ventilatory response to AH.

Traditional and commercial turkeys show similar susceptibility to foot pad dermatitis and behavioural evidence of pain

1. An experiment was conducted to compare the development and clinical significance of foot pad dermatitis (FPD) in 4 lines of turkey poults kept on wet or dry litter for 6 d. 2. Turkeys kept on wet litter were less active and expressed fewer unique sequences of behaviour than poults kept on dry litter, suggesting that high FPD scores are associated with pain during movement. 3. Heavier lines of turkeys had higher mean foot scores that developed earlier, than those in a traditional line, but the effect was relatively small and not statistically significant after 6 d, whereas there were large differences between individuals within line. 4. Body weight gains were greater, and feed intake was lower in the commercial lines kept on dry litter compared with wet litter. There were no differences in water intake between poults kept on wet or dry litter.

The role of DAB2IP in androgen receptor activation during prostate cancer progression

Altered androgen-receptor (AR) expression and/or constitutively active AR are commonly associated with prostate cancer (PCa) progression. Targeting AR remains a focal point for designing new strategy of PCa therapy. Here, we have shown that DAB2IP, a novel tumor suppressor in PCa, can inhibit AR-mediated cell growth and gene activation in PCa cells via distinct mechanisms. DAB2IP inhibits the genomic pathway by preventing AR nuclear translocation or phosphorylation and suppresses the non-genomic pathway via its unique functional domain to inactivate c-Src. Also, DAB2IP is capable of suppressing AR activation in an androgen-independent manner. In addition, DAB2IP can inhibit several AR splice variants showing constitutive activity in PCa cells. In DAB2IP(-/-) mice, the prostate gland exhibits hyperplastic epithelia, in which AR becomes more active. Consistently, DAB2IP expression inversely correlates with AR activation status particularly in recurrent or metastatic PCa patients. Taken together, DAB2IP is a unique intrinsic AR modulator in normal cells, and likely can be further developed into a therapeutic agent for PCa.

New Group IV chemical motifs for improved dielectric permittivity of polyethylene

An enhanced dielectric permittivity of polyethylene and related polymers, while not overly sacrificing their excellent insulating properties, is highly desirable for various electrical energy storage applications. In this computational study, we use density functional theory (DFT) in combination with modified group additivity based high throughput techniques to identify promising chemical motifs that can increase the dielectric permittivity of polyethylene. We consider isolated polyethylene chains and allow the CH2 units in the backbone to be replaced by a number of Group IV halides (viz., SiF2, SiCl2, GeF2, GeCl2, SnF2, or SnCl2 units) in a systematic, progressive, and exhaustive manner. The dielectric permittivity of the chemically modified polyethylene chains is determined by employing DFT computations in combination with the effective medium theory for a limited set of compositions and configurations. The underlying chemical trends in the DFT data are first rationalized in terms of various tabulated atomic properties of the constituent atoms. Next, by parametrizing a modified group contribution expansion using the DFT data set, we are able to predict the dielectric permittivity and bandgap of nearly 30,000 systems spanning a much larger part of the configurational and compositional space. Promising motifs which lead to simultaneously large dielectric constant and band gap in the modified polyethylene chains have been identified. Our theoretical work is expected to serve as a possible motivation for future experimental efforts.

Thrombotic risk factors in Chinese Budd-Chiari syndrome patients. An observational study with a systematic review of the literature

In Western countries, thrombotic risk factors for Budd-Chiari syndrome (BCS) are very common, including factor V Leiden mutation, prothrombin G20210A mutation, myeloproliferative neoplasms, paroxysmal nocturnal haemoglobinuria, etc. However, the data regarding thrombotic risk factors in Chinese BCS patients are extremely limited. An observational study was conducted to examine this issue. A total of 246 BCS patients who were consecutively admitted to our department between July 1999 and December 2011 were invited to be examined for thrombotic risk factors. Of these, 169 patients were enrolled. Neither factor V Leiden mutation nor prothrombin G20210A mutation was found in any of 136 patients tested. JAK2 V617F mutation was positive in four of 169 patients tested. Neither MPL W515L/K mutation nor JAK2 exon 12 mutation was found in any of 135 patients tested. Overt myeloproliferative neoplasms were diagnosed in five patients (polycythemia vera, n=3; essential thrombocythemia, n=1; idiopathic myelofibrosis, n=1). Two of them had positive JAK2 V617F mutation. Both CD55 and CD59 deficiencies were found in one of 166 patients tested. This patient had a previous history of paroxysmal nocturnal haemo-globinuria before BCS. Anticardiolipin IgG antibodies were positive or weakly positive in six of 166 patients tested. Hyperhomocysteinaemia was found in 64 of 128 patients tested. 5,10-methylenetetrahydrofolate reductase C677T mutation was found in 96 of 135 patients tested. In conclusion, factor V Leiden mutation, prothrombin G20210A mutation, myeloproliferative neoplasms, and paroxysmal nocturnal haemoglobinuria are very rare in Chinese BCS patients, suggesting that the etiological distribution of BCS might be different between Western countries and China.

The tumor suppressor p53 regulates c-Maf and Prox-1 to control lens differentiation

The tumor suppressor p53 plays a key role in regulating apoptosis and cell cycle progression. In addition, p53 is implicated in control of cell differentiation in muscle, the circulatory system, ocular lens and various carcinoma tissues. However, the mechanisms by which p53 controls cell differentiation are not fully understood. Here we present evidence that p53 directly regulates c-Maf and Prox1, two important transcription factors controlling differentiation in the ocular lens. First, human and murine c-Maf and Prox1 gene promoters contain authentic p53 DNA binding sites. Second, p53 directly binds to the p53 binding sites found in the promoter regions. Third, exogenous p53 induces dose-dependent expression of the luciferase report gene driven by both c-Maf and Prox1 promoters, and p53 binds to both promoters in the ChIP assays. Fourth, in the in vitro differentiation model, knockdown of p53 significantly inhibits lens differentiation which is associated with downregulated expression of c-Maf and Prox1. Finally, in p53 knockout mice, the expression of c-Maf and Prox1 are significantly altered. Together, our results reveal that p53 regulates lens differentiation through modulation of two important transcription factors, c-Maf and Prox1, and through them p53 thus controls expression of various differentiation-related downstream crystallin genes.

siRNA silencing of gene expression in trabecular meshwork: RhoA siRNA reduces IOP in mice

Few reports described efficient transfection in the trabecular meshwork (TM) in vivo. In the present study, we investigated the distribution of cy3-labeled siRNAs after giving injection into the anterior chamber (AC) and explored the use of RhoA siRNA (siRhoA) to modulate intraocular pressure (IOP) through downregulation of RhoA gene and protein expression. Cy3-labeled siRNAs were injected into the AC to investigate the distribution. In addition, siRhoA was applied to normal and DEX-induced elevated IOP mice. The RhoA gene was detected at 1d post-injection (PI) using real-time RT-PCR. Proteins were examined using immunofluorescence staining at 1, 2, and 3 day PI. IOP was measured pre- and post-injection using a TONOPEN. Toxicity was preliminarily assessed using clinical observation and hematoxylin-eosin staining. The study demonstrated that cy3-labeled siRNAs accumulated in mouse TM in a dose-dependent manner, with a peak at 24h PI. There was no visible siRNA fluorescence in the corneal endothelium, and little in the iris. siRhoA caused large decreases in RhoA mRNA and protein expression in mouse TM (p < 0.01). In normal mice, injections of siRhoA induced decreases in IOP, by 2d, with recovery to baseline by 3d PI. For DEX-treated animals, IOP significantly decreased from 2d to 5d PI (p < 0.05). There was no obvious toxicity after the siRhoA application. These results suggest that (1) siRNA injection into the AC leads to transient gene transfection in TM; (2) inhibiting RhoA expression in TM with siRNA is effective in suppressing elevated IOP in mice, suggesting that siRhoA is a potential pharmaceutical intervention for glaucoma.

The efficacy and safety of antiviral therapy with lamivudine to stop the vertical transmission of hepatitis B virus

The purpose of this study was to investigate the efficacy and safety of lamivudine (LAM) in stopping the vertical transmission of hepatitis B virus (HBV). Pregnant women with normal alanine transaminase (ALT) (n = 100) and with abnormal ALT (n = 100) who were positive for hepatitis B e antigen (HBeAg), and with HBV DNA (deoxyribonucleic acid) levels ≥1.0 × 107 copies/ml were enrolled in this study. One hundred volunteers (50 with normal ALT, 50 with abnormal ALT) received 100 mg of LAM daily from the 24th to 32nd week of gestation and the untreated 100 volunteers served as controls. All infants received passive-active immunoprophylaxis. Compared to the control group, the study group got a marked reduction in serum levels (P < 0.001) and high negativity (P < 0.001) of HBV DNA before delivery. They also got normalization in ALT levels as much as controls received general medication (P > 0.05). The prenatal transmission rate in the study group was significantly lower than that of the control group (P < 0.05). There were no differences in incidences of congenital malformation between the two groups (P > 0.05). LAM treatment can effectively and safely stop vertical transmission of HBV and normalize the ALT levels of pregnant women.

Nonlinear population pharmacokinetics of sirolimus in patients with advanced cancer

Sirolimus, the prototypical inhibitor of the mammalian target of rapamycin, has substantial antitumor activity. In this study, sirolimus showed nonlinear pharmacokinetic characteristics over a wide dose range (from 1 to 60 mg/week). The objective of this study was to develop a population pharmacokinetic (PopPK) model to describe the nonlinearity of sirolimus. Whole blood concentration data, obtained from four phase I clinical trials, were analyzed using a nonlinear mixed-effects modeling (NONMEM) approach. The influence of potential covariates was evaluated. Model robustness was assessed using nonparametric bootstrap and visual predictive check approaches. The data were well described by a two-compartment model incorporating a saturable Michaelis–Menten kinetic absorption process. A covariate analysis identified hematocrit as influencing the oral clearance of sirolimus. The visual predictive check indicated that the final pharmacokinetic model adequately predicted observed concentrations. The pharmacokinetics of sirolimus, based on whole blood concentrations, appears to be nonlinear due to saturable absorption.

Meta-analysis: effect of preoperative infliximab use on early postoperative complications in patients with ulcerative colitis undergoing abdominal surgery

BACKGROUND

Infliximab is widely used in severe and refractory ulcerative colitis (UC). The results of clinical studies are inconsistent on whether preoperative infliximab use increases early postoperative complications in UC patients.

AIM

To determine the clinical safety and efficacy of preoperative infliximab treatment in UC patients with regard to short-term outcomes following abdominal surgery.

METHODS

PubMed, Embase databases were searched for controlled observational studies comparing postsurgical morbidity in UC patients receiving infliximab preoperatively with those not on infliximab. The primary endpoint was total complication rate. Secondary endpoints included the rate of infectious and non-infectious complications. We calculated pooled odds ratios (ORs) with 95% confidence intervals (CIs) as summary measures.

RESULTS

A total of 13 studies involving 2933 patients were included in our meta-analysis. There was no significant association between infliximab therapy preoperatively and total (OR = 1.09, 95% CI: 0.87-1.37, P = 0.47), infectious (OR = 1.10, 95% CI: 0.51-2.38, P = 0.81) and non-infectious (OR = 1.10, 95% CI: 0.76-1.59, P = 0.61) postoperative complications respectively. Infliximab might be a protective factor against infection for the use within 12 weeks prior to surgery (OR = 0.43, 95% CI: 0.22-0.83, P = 0.01). No publication bias was found.

CONCLUSION

Preoperative infliximab use does not increase the risk of early postoperative complications in patients with ulcerative colitis undergoing abdominal surgery.

Evaluation of the hok/sok killer locus for enhanced plasmid stability

The effectiveness of the hok/sok plasmid stability locus and mechanism of cloned-gene loss was evaluated in shake-flask cultures. Addition of the hok/sok locus dramitically increasedapparent plasmid segregational stability to the hok/sok(-) control. In terms of the number of generations before 10%of the population became plasmid-free, segregational stability was increased by 11- to 20-fold in different media in the absence of induction of the cloned-gene (hok/sok(+) plasmid stable for over 200 generations in all media tested). With constant expression of beta-galactosidase in the absence of an tibiotic, the segregational stability of the plasmid containing hok/sok was incresed more than 17- to 30-fold when beta-galactosidase was expressed at 7-15 wt % of total cell protein. Although the hok/sok system stabilized the plasmid well infour different media (Luria-Bertani (LB), LB glucose, M9C Trp, and a representative fedbatch medium), the ability of hok/sok to maintain the plasmid with induction of the cloned gene decreased as the complexity of the media increased. This result is better interpreted in terms of the influence of cloned-gene expression on plasmidmaintenance; plasmid segregational stability decreased linearly as specificbeta-galactosidase activity increased. (c) 1994 John Wiley & Sons, Inc.

Adsorption stripping voltammetry of phenol at Nafion-modified glassy carbon electrode in the presence of surfactants

In this paper, a new voltammetric method for the determination of phenol is described. In pH 8.00 phosphate buffer and in the presence of long-chain cationic surfactant-cetyltrimethylammonium bromide-phenol has a very sensitive oxidation peak at 0.47 V (vs. SCE) on the Nafion-modified glassy carbon electrode (GCE). The experimental parameters, such as supporting electrolyte and pH values, amounts of Nafion, varieties and concentration of surfactants, accumulation potential and time, as well as scan rate were optimized. The peak current is linear with the concentration of phenol in the range from 8x10(-9) to 1x10(-5) M, and the detection limit is 1x10(-9) M after being accumulated at -0.50 V (vs. SCE) for 3 min. Trace levels of phenol in water samples were determined by using this voltammetric method, the average recovery was calculated to be 99.56%.

A correlative analysis of epidemiologic and molecular characteristics of methicillin-resistant Staphylococcus aureus clones from diverse geographic locations with virulence measured by a Caenorhabditis elegans host model

Methicillin-resistant Staphylococcus aureus (MRSA) strains from different geographic areas have different genetic backgrounds, suggesting independent clonal evolutions. To better understand the virulence of MRSA strains and the relationship to their clonal and geographic origins, we undertook an analysis of epidemiologic, molecular, and virulence characteristics of a large number of MRSA isolates from geographically diverse origins, in a Caenorhabditis elegans infection model. A total of 99 MRSA isolates collected between 1993 and 2010 at the Geneva University Hospitals from diverse global origins were characterized with Panton–Valentine leukocidin (PVL), toxic shock syndrome toxin (TSST), accessory gene regulator (agr) group, staphylococcal cassette chromosome mec (SCCmec), S. aureus protein A (spa), multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE) typing. Epidemiologic data were provided from clinical records. The bacterial virulence was tested in a C. elegans host model. The inter-relationships of epidemiological/molecular characteristics in association with nematocidal activities were analyzed with univariate and two-factor analysis of variance (ANOVA). Community-associated MRSA (CA-MRSA) strains were more virulent than hospital-associated MRSA (HA-MRSA), with higher nematocidal activities in CA-MRSA strains (0.776 vs. 0.506, p = 0.0005). All molecular characteristics (PVL, TSST, spa, SCCmec, MLST, and PFGE types) showed a significant association with nematocidal activities on univariate analysis (p < 0.005). PVL was not a significant predictor after adjusting for genomic backgrounds using spa, MLST, or PFGE typing. The dominant CA-MRSA strains in North America showed higher nematocidal activities than strains from other regions (p < 0.0001). Strains with global origins containing distinct genetic backgrounds have different virulence in the C. elegans model. Nematocidal activities were most highly correlated with SCCmec, spa, MLST, and PFGE typing, suggesting that genomic background rather than a single exotoxin characteristic was the most discriminating predictor of virulence.

Seebeck rectification enabled by intrinsic thermoelectrical coupling in magnetic tunneling junctions

An intrinsic thermoelectric coupling effect in the linear response regime of magnetic tunneling junctions (MTJ) is reported. In the dc response, it leads to a nonlinear correction to Ohm's law. Dynamically, it enables a novel Seebeck rectification and second harmonic generation, which apply for a broad frequency range and can be magnetically controlled. A phenomenological model on the footing of the Onsager reciprocal relation and the principle of energy conservation explains very well the experimental results obtained from both dc and frequency-dependent transport measurements performed up to GHz frequencies. Our work refines previous understanding of magnetotransport and microwave rectification in MTJs. It forms a new foundation for utilizing spin caloritronics in high-frequency applications.

MicroRNA-7 functions as an anti-metastatic microRNA in gastric cancer by targeting insulin-like growth factor-1 receptor

Metastasis is a major clinical obstacle in the treatment of gastric cancer (GC) and it accounts for the majority of cancer-related mortality. MicroRNAs have recently emerged as regulators of metastasis by acting on multiple signaling pathways. In this study, we found that miR-7 is significantly downregulated in highly metastatic GC cell lines and metastatic tissues. Both gain-of-function and loss-of-function experiments showed that increased miR-7 expression significantly reduced GC cell migration and invasion, whereas decreased miR-7 expression dramatically enhanced cell migration and invasion. In vivo metastasis assays also demonstrated that overexpression of miR-7 markedly inhibited GC metastasis. Moreover, the insulin-like growth factor-1 receptor (IGF1R) oncogene, which is often mutated or amplified in human cancers and functions as an important regulator of cell growth and tumor invasion, was identified as a direct target of miR-7. Silencing of IGF1R using small interefering RNA (siRNA) recapitulated the anti-metastatic function of miR-7, whereas restoring the IGF1R expression attenuated the function of miR-7 in GC cells. Furthermore, we found that suppression of Snail by miR-7, through targeting IGF1R, increased E-cadherin expression and partially reversed the epithelial-mesenchymal transition (EMT). Finally, analyses of miR-7 and IGF1R levels in human primary GC with matched lymph node metastasis tissue arrays revealed that miR-7 is inversely correlated with IGF1R expression. The present study provides insight into the specific biological behavior of miR-7 in EMT and tumor metastasis. Targeting this novel miR-7/IGF1R/Snail axis would be helpful as a therapeutic approach to block GC metastasis.

Transgastric endoscopic gastroenterostomy using a partially covered occluder: a canine feasibility study

BACKGROUND AND STUDY AIMS

The use of natural orifice transluminal endoscopic surgery (NOTES) for gastroenterostomy has been previously reported, but it remains technically challenging and additional assistance is often needed. The aim of this study was to develop and evaluate a novel method for the creation of a gastroenterostomy using NOTES with an occluder.

METHODS

Transgastric endoscopic gastroenterostomy was performed in 12 healthy female dogs using a therapeutic upper gastrointestinal endoscope and a partially covered occluder. The occluder was removed with a snare 1 week later. The patency of the gastroenterostomy was confirmed by endoscopy, contrast radiological study, necropsy, and histological examination after 2 weeks.

RESULTS

NOTES gastroenterostomy with an occluder was successful in all 12 dogs. The mean operative time was 32.3 ± 10.3 min (range 20.3 - 53.5). One dog (the first; 8.3 %) died 4 days after the operation of severe intra-abdominal infection due to incorrect deployment of the occluder and poor bowel preparation. Minor bleeding occurred at the anastomosis after removal of the occluder in two of the remaining dogs (18.2 %). Necropsy revealed postoperative adhesions that had developed at the anastomotic site in one dog (9.1 %). No anastomotic leakage or intestinal obstruction was observed. Complete healing of the anastomosis was confirmed on histological evaluation.

CONCLUSION

Gastroenterostomy performed entirely by NOTES using an occluder was technically feasible in this survival animal model.

Donor-specific HLA antibodies in a cohort comparing everolimus with cyclosporine after kidney transplantation

Donor-specific HLA antibodies (DSA) have a negative impact on kidney graft survival. Therefore, we analyzed the occurrence of DSA and antibody-mediated rejection (AMR) in patients from two prospective randomized trials in our center. At 3-4.5 months posttransplant 127 patients were randomized to continue cyclosporine or converted to everolimus therapy. The presence of DSA was prospectively assessed using Luminex assays. AMR was defined according to the Banff 2009 classification. Antibody screening was available in 126 patients with a median follow-up of 1059 days. Seven out of 65 (10.8%) patients on cyclosporine developed DSA after a median of 991 days. In comparison, 14/61 patients (23.0%) randomized to everolimus developed DSA after 551 days (log-rank: p = 0.048). Eight patients on everolimus compared to two patients on cyclosporine developed AMR (log-rank: p = 0.036). Four of 10 patients with AMR-all in the everolimus group-lost their graft. A multivariate regression model revealed everolimus, >3 mismatches and living donor as significant risk factors for DSA. Acute rejection within the first year, >3 mismatches, everolimus and living donor were independent risk factors for AMR. This single center analysis demonstrates for the first time that everolimus-based immunosuppression is associated with an increased risk for the development of DSA and AMR.

Thermal and laser properties of Nd:Lu₃Sc₁.₅Ga₃.₅O₁₂ for high power dual-wavelength laser

We measured the thermal properties of Nd:Lu₃Sc₁.₅Ga₃.₅O₁₂ (Nd:LuSGG) crystal, including the thermal expansion coefficient, specific heat, and thermal diffusion coefficient. The calculated thermal conductivity is 4.4 W/mK at room temperature. A high-power continuous-wave and passively Q-switched Nd:LuSGG laser was also demonstrated. Continuous-wave output power of 6.96 W is obtained which is the highest power with this material. For the first time to our knowledge, the passively Q-switched Nd:LuSGG laser is reported with the shortest pulse width, largest pulse energy, and highest peak power are achieved to be 5.1 ns, 62.5 μJ, and 12 kW, respectively. By spectral analysis, it has been found that the Nd:LuSGG laser was located at 1059 nm under low pump power, and became dual-wavelength at 1061.5 and 1059 nm when the incident pump power is over 2.27 W. The generating mechanism of dual-wavelength laser is also discussed.

Hydrophobic anions potently and uncompetitively antagonize GABA(A) receptor function in the absence of a conventional binding site

BACKGROUND AND PURPOSE

A 'lock-and-key' binding site typically accounts for the effect of receptor antagonists. However, sulphated neurosteroids are potent non-competitive antagonists of GABA(A) receptors without a clear structure-activity relationship. To gain new insights, we tested two structurally unrelated hydrophobic anions with superficially similar properties to sulphated neurosteroids.

EXPERIMENTAL APPROACH

We used voltage-clamp techniques in Xenopus oocytes and hippocampal neurons to characterize dipicrylamine (DPA) and tetraphenylborate (TPB), compounds previously used to probe membrane structure and voltage-gated ion channel function.

KEY RESULTS

Both DPA and TPB potently antagonized GABA(A) receptors. DPA exhibited an IC₅₀ near 60 nM at half-maximal GABA concentration and antagonism with features indistinguishable from pregnenolone sulphate antagonism, including sensitivity to a point mutation in transmembrane domain 2 of the α1 subunit. Bovine serum albumin, which scavenges free membrane-associated DPA, accelerated both capacitance offset and antagonism washout. Membrane interactions and antagonism were explored using the voltage-dependent movement of DPA between membrane leaflets. Washout of DPA antagonism was strongly voltage-dependent, paralleling DPA membrane loss, although steady-state antagonism lacked voltage dependence. At antagonist concentrations, DPA failed to affect inhibitory post-synaptic current (IPSC) amplitude or decay, but DPA accelerated pharmacologically prolonged IPSCs.

CONCLUSIONS AND IMPLICATIONS

Neurosteroid-like GABA(A) receptor antagonism appears to lacks a conventional binding site. These features highlight key roles of membrane interactions in antagonism. Because its membrane mobility can be controlled, DPA may be a useful probe of GABA(A) receptors, but its effects on excitability via GABA(A) receptors raise caveats for its use in monitoring neuronal activity.