Biallelic truncating mutations in FMN2, encoding the actin-regulatory protein Formin 2, cause nonsyndromic autosomal-recessive intellectual disability

Dendritic spines represent the major site of neuronal activity in the brain; they serve as the receiving point for neurotransmitters and undergo rapid activity-dependent morphological changes that correlate with learning and memory. Using a combination of homozygosity mapping and next-generation sequencing in two consanguineous families affected by nonsyndromic autosomal-recessive intellectual disability, we identified truncating mutations in formin 2 (FMN2), encoding a protein that belongs to the formin family of actin cytoskeleton nucleation factors and is highly expressed in the maturing brain. We found that FMN2 localizes to punctae along dendrites and that germline inactivation of mouse Fmn2 resulted in animals with decreased spine density; such mice were previously demonstrated to have a conditioned fear-learning defect. Furthermore, patient neural cells derived from induced pluripotent stem cells showed correlated decreased synaptic density. Thus, FMN2 mutations link intellectual disability either directly or indirectly to the regulation of actin-mediated synaptic spine density.

CLP1 founder mutation links tRNA splicing and maturation to cerebellar development and neurodegeneration

Neurodegenerative diseases can occur so early as to affect neurodevelopment. From a cohort of more than 2,000 consanguineous families with childhood neurological disease, we identified a founder mutation in four independent pedigrees in cleavage and polyadenylation factor I subunit 1 (CLP1). CLP1 is a multifunctional kinase implicated in tRNA, mRNA, and siRNA maturation. Kinase activity of the CLP1 mutant protein was defective, and the tRNA endonuclease complex (TSEN) was destabilized, resulting in impaired pre-tRNA cleavage. Germline clp1 null zebrafish showed cerebellar neurodegeneration that was rescued by wild-type, but not mutant, human CLP1 expression. Patient-derived induced neurons displayed both depletion of mature tRNAs and accumulation of unspliced pre-tRNAs. Transfection of partially processed tRNA fragments into patient cells exacerbated an oxidative stress-induced reduction in cell survival. Our data link tRNA maturation to neuronal development and neurodegeneration through defective CLP1 function in humans.

Hepatitis B virus X protein accelerates hepatocarcinogenesis with partner survivin through modulating miR-520b and HBXIP

BACKGROUND

Hepatitis B virus X protein (HBx) plays crucial roles in hepatocarcinogenesis. However, the underlying mechanism remains elusive. We have reported that HBx is able to up-regulate survivin in hepatocellular carcinoma tissues. The oncopreotein hepatitis B X-interacting protein (HBXIP), a target of miR-520b, is involved in the development of cancer. In this study, we focus on the investigation of hepatocarcinogenesis mediated by HBx.

METHODS

The expression of HBx and survivin was examined in the liver tissues of HBx-Tg mice. The effect of HBx/survivin on the growth of LO2-X-S cells was determined by colony formation and transplantation in nude mice. The effect of HBx/survivin on promoter of miR-520b was determined by Western blot analysis, luciferase reporter gene assay, co-immunoprecipitation (co-IP) and chromatin immunoprecipitation (ChIP), respectively. The expression of HBx, survivin and HBXIP was detected by immunohistochemistry and real-time PCR in clinical HCC tissues, respectively. The DNA demethylation of HBXIP promoter was examined. The functional influence of miR-520b and HBXIP on proliferation of hepatoma cells was analyzed by MTT, colony formation, EdU and transplantation in nude mice in vitro and in vivo.

RESULTS

In this study, we provided evidence that HBx up-regulated survivin in the liver cancer tissues of HBx-Tg mice aged 18 M. The engineered LO2 cell lines with survivin and/or HBx were successfully established, termed LO2-X-S. MiR-520b was down-regulated in LO2-X-S cells and clinical HCC tissues. Our data revealed that HBx survivin-dependently down-regulated miR-520b through interacting with Sp1 in the cells. HBXIP was highly expressed in LO2-X-S cells, liver cancer tissues of HBx-Tg mice aged 18 M and clinical HCC tissues (75.17%, 112/149). The expression level of HBXIP was positively associated with those of HBx or survivin in clinical HCC tissues. In addition, we showed that HBx survivin-dependently up-regulated HBXIP through inducing demethylation of HBXIP promoter in LO2-X-S cells and clinical HCC tissues. In function, low level miR-520b and high level HBXIP mediated by HBx with partner survivin contributed to the growth of LO2-X-S cells in vitro and in vivo.

CONCLUSION

HBx accelerates hepatocarcinogenesis with partner survivin through modulating tumor suppressor miR-520b and oncoprotein HBXIP.

[Effects of recombinant human interleukin-11 on LPS-induced intestinal epithelial cell injury in rats]

OBJECTIVE

To study the effects of recombinant human interleukin-11 (rhIL-11) on the proliferation and apoptosis of rat intestinal epithelial cell line (IEC-6).

METHODS

IEC-6 cells were treated with LPS to establish necrotizing enterocolitis (NEC) model in vitro. rhIL-11 (100 ng/mL) was administered following LPS treatment and these cells were used as the IL-11 treatment group. The cells treated with normal saline only served as the control group. MTT assay was used to determine an optimal concentration (5-200 μg/mL) and time (1-24 h). MTT assay was used to measure the proliferation of IEC-6 cells at 3, 6, 9 and 12 hours after rhIL-11 treatment. Flow cytometry was used to evaluate the apoptosis of IEC-6 cells.

RESULTS

IEC-6 cells treated with various concentrations of LPS at various time points showed a lower proliferation than the control group (P<0.05). After 9 hours of rhIL-11 treatment, the proliferation activity of IEC-6 cells in the IL-11 treatment group significantly increased compared with the NEC model group without rhIL-11 treatment (P<0.05), reaching to the level of the control group. The total apoptotic and necrotic rate of IEC-6 cells in the IL-11 treatment group decreased significantly compared with the NEC model group without rhIL-11 treatment (P<0.01), but were still higher than the control group (P<0.05).

CONCLUSIONS

rhIL-11 can promote proliferation and reduce apoptotic and necrotic rates of IEC-6 cells treated with LPS.

[Perinatal high-risk factors for necrotizing enterocolitis in preterm infants: a case-control study]

OBJECTIVE

To study the timing of presentation and perinatal high-risk factors for necrotizing enterocolitis (NEC) in preterm infants with a gestational age of <33 weeks.

METHODS

A case-control study was conducted in 49 preterm infants with NEC (gestational age <33 weeks) who were admitted to the Neonatal Intensive Care Unit of Beijing Bayi Children's Hospital between October 1, 2010 and December 30, 2012, as well as preterm infants without NEC during the same period. The timing of presentation of NEC was retrospectively analyzed, and the perinatal high-risk factors for NEC were determined by multivariate logistic regression analysis.

RESULTS

The median age of onset was 17.5 days (range: 3-106 d) in preterm infants with NEC. Sex, being small for gestational age, delivery mode and antenatal corticosteroid therapy were not associated with the development of NEC; low gestational age, low birth weight and neonatal asphyxia increased the risk of NEC, and low gestational age was identified as an independent high-risk factor for the development of NEC.

CONCLUSIONS

Low gestational age is an important risk factor for the development NEC in preterm infants under 33 weeks' gestation, and the median age of onset is 17.5 days.

X-ray photoelectron spectroscopy study of the passivation of NiAl(100) by water vapor

The oxidation of NiAl(100) surfaces by water vapor is studied using X-ray photoelectron spectroscopy (XPS) to elucidate the effect of temperature and vapor pressure on the surface passivation mechanism of the NiAl alloy. The water-vapor oxidation at ambient temperature (25 °C) results in self-limiting Al(OH)3/Al2O3 bilayer film growth to a less extent of the limiting thickness regimes, in which the growth of the inner Al2O3 layer occurs via dehydration of the outer Al(OH)3 layer. The growth of the passivating overlayer at the ambient temperature depletes Al and forms a Ni-rich layer at the oxide/alloy interface that impedes supply of Al atoms to the outer surface for Al(OH)3 formation via the hydration reaction, whereby resulting in a more Al-deficient structure of the outer Al(OH)3 layer upon increasing the vapor pressure. In contrast, the water-vapor oxidation at 300 °C results in Al2O3 single-layer film growth to a larger limiting thickness without involving the transient hydroxide phase of Al(OH)3. It is shown that increasing the oxidation temperatures results in the formation of a more compact Al2O3 film owning to the enhanced bulk diffusion rate that maintains an adequate supply of Al atoms to the oxide/alloy interface to sustain the oxide film growth to the full extent of the limiting thickness.

Mutations in CSPP1 lead to classical Joubert syndrome

Joubert syndrome and related disorders (JSRDs) are genetically heterogeneous and characterized by a distinctive mid-hindbrain malformation. Causative mutations lead to primary cilia dysfunction, which often results in variable involvement of other organs such as the liver, retina, and kidney. We identified predicted null mutations in CSPP1 in six individuals affected by classical JSRDs. CSPP1 encodes a protein localized to centrosomes and spindle poles, as well as to the primary cilium. Despite the known interaction between CSPP1 and nephronophthisis-associated proteins, none of the affected individuals in our cohort presented with kidney disease, and further, screening of a large cohort of individuals with nephronophthisis demonstrated no mutations. CSPP1 is broadly expressed in neural tissue, and its encoded protein localizes to the primary cilium in an in vitro model of human neurogenesis. Here, we show abrogated protein levels and ciliogenesis in affected fibroblasts. Our data thus suggest that CSPP1 is involved in neural-specific functions of primary cilia.

Sensitive and selective detection of copper ions with highly stable polyethyleneimine-protected silver nanoclusters

Copper is a highly toxic environmental pollutant with bioaccumulative properties. Therefore, sensitive Cu(2+) detection is very important to prevent over-ingestion, and visual detection using unaugmented vision is preferred for practical applications. In this study, hyperbranched polyethyleneimine-protected silver nanoclusters (hPEI-AgNCs) were successfully synthesized using a facile, one-pot reaction under mild conditions. The hPEI-AgNCs were very stable against extreme pH, ionic strength, temperature, and photoillumination and could act as sensitive and selective Cu(2+) sensing nanoprobes in aqueous solutions with a 10 nM limit of detection. In addition, hPEI-AgNCs-doped agarose hydrogels were developed as an instrument-free and regenerable platform for visual Cu(2+) and water quality monitoring.

AMPD2 regulates GTP synthesis and is mutated in a potentially treatable neurodegenerative brainstem disorder

Purine biosynthesis and metabolism, conserved in all living organisms, is essential for cellular energy homeostasis and nucleic acid synthesis. The de novo synthesis of purine precursors is under tight negative feedback regulation mediated by adenosine and guanine nucleotides. We describe a distinct early-onset neurodegenerative condition resulting from mutations in the adenosine monophosphate deaminase 2 gene (AMPD2). Patients have characteristic brain imaging features of pontocerebellar hypoplasia (PCH) due to loss of brainstem and cerebellar parenchyma. We found that AMPD2 plays an evolutionary conserved role in the maintenance of cellular guanine nucleotide pools by regulating the feedback inhibition of adenosine derivatives on de novo purine synthesis. AMPD2 deficiency results in defective GTP-dependent initiation of protein translation, which can be rescued by administration of purine precursors. These data suggest AMPD2-related PCH as a potentially treatable early-onset neurodegenerative disease.

Disassembly mediated fluorescence recovery of gold nanodots for selective sulfide sensing

We report a one-pot, two-step strategy to synthesize fluorescent gold nanodots (AuNDs) co-modified with 1-(10-mercaptodecyl)-5-methylpyrimidine-2,4-dione (TSH) and 11-mercaptoundecanoic acid (MUA) through a ligand exchange reaction and demonstrate their capability of selective sulfide sensing in aqueous media on the basis of fluorescence recovery.

Duloxetine use in chronic painful conditions--individual patient data responder analysis

Background

Duloxetine has been studied in four distinct chronic pain conditions – osteoarthritis (OA), fibromyalgia, chronic low back pain (CLBP) and diabetic peripheral neuropathic pain (DPNP). These trials have involved large numbers of patients with at least moderate pain, and have used similar methods for recording pain intensity, over about 12 weeks.

Methods

Data from the trials were pooled according to painful condition, and reanalysed at the level of the individual patient and using increasing levels of pain intensity reduction (<15%, 15–29%, 30–49%, ≥50%), with different imputation methods on withdrawal.

Results

The proportion of patients recording at least 50% pain intensity reduction plateaued after 2–6 weeks in fibromyalgia, and 8–12 weeks in other conditions. The duloxetine-specific benefit [number needed to treat (NNT) for at least 50% pain intensity reduction] was fairly constant after about 2 weeks for DPNP and fibromyalgia and after about 4 or 5 weeks for OA and CLBP. In all conditions, responses were bimodal, with patients generally experiencing either very good or very poor pain relief. Last-observation-carried-forward imputation produced numerically and occasionally statistically better (lower) NNTs than use of baseline-observation-carried-forward (true response).

Conclusions

Baseline-observation-carried-forward (true response), which combines the success of high levels of pain relief with the failure to experience pain relief on withdrawal of the drug is conservative and probably reflective of clinical practice experience. The distribution of effect was not normal; few patients had the average response and averages are not an appropriate descriptor for these data.

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Ursolic acid induces apoptosis via Akt/NF-κB signaling suppression in T24 human bladder cancer cells

The Akt/NF-κB pathway is involved in numerous anti‑apoptotic and drug resistance events which occur in various types of bladder cancer. The present study investigated the role of ursolic acid in the regulation of anti-apoptotic Akt and NF-κBp65 signaling. T24 human bladder cancer cells were treated with ursolic acid at final concentrations of 12.5, 25 or 50 µmol/l for 48 h. Quantitative PCR (qPCR) and western blotting were performed to detect mRNA and protein expression, respectively. The results showed that anti-apoptotic phospho-Akt1 (pAkt1), phospho-IκBα (pIκBα), NF-κBp65 and Bcl-2 were inhibited and pro-apoptotic caspase-3 was upregulated in a dose‑dependent manner. A 50 µmol/l dose of ursonic acid decreased the mRNA expression levels of anti-apoptotic NF-κBp65 and Bcl-2 0.17 (8.9/52.6)-fold and 0.22 (9.5/42.3)‑fold, respectively. The pro-apoptotic caspase-3 mRNA expression levels were upregulated 4.78 (38.7/8.1)-fold. The anti-apoptotic pAkt1, pIκBα, NF-κBp65 and Bcl-2 protein levels were downregulated to 5.1 (blot grayscales vs. control at 32.3), 3.2 (vs. 24.2), 8.5 (vs. 45.1) and 9.2 (vs. 40.3). The protein levels of pro-apoptotic caspase-3 were upregulated to 20.7 (vs. 4.7). The proliferative activity of T24 cells treated with 12.5, 25.0 and 50.0 µmol/l ursolic acid was significantly reduced compared with that of control cells (83.8, 56.2 and 31.5 vs. 97.6%, respectively, P<0.05 for each). In conclusion, ursolic acid is important in inducing apoptosis via the suppression of Akt/NF-κB signaling in T24 human bladder cancer cells and this occurs in a dose-dependent manner. Ursolic acid may therefore serve as a naturally occurring candidate drug for the prevention and treatment of bladder cancer.

Abstract 3948: An inhibitor of uPA reduces osteosarcoma metastasis by blocking signaling in tumour cells and the bone marrow microenvironment

Osteosarcoma (OS) is the most common primary malignant bone tumour in children and adolescents. Pulmonary metastasis is the major complication of OS and results in just 10-20% long-term survival. We have shown that metastatic potential is an inherent characteristic of OS, and that the bone microenvironment contributes to OS metastasis (Endo-Munoz et al. Cancer Res 70:7063-72, 2010). Specifically, loss of osteoclasts increases the metastatic potential of OS, and bone marrow cells (BMC) increase the migration of OS cells. However, the factors regulating inherent and BMC-mediated metastasis have not been elucidated. We have used a multi-omics approach to identify genes and proteins that may mediate OS metastasis. We found very high levels of mRNA and protein expression and secretion of the urokinase plasminogen activator (uPA) and its receptor (uPAR) exclusively in metastatic OS. Addition of uPA-rich OS conditioned medium to metastatic OS cells significantly (P &lt; 0.007) increased their basal in vitro migration to levels similar to those observed with recombinant human uPA. On the other hand, overall migration was significantly (P &lt; 0.005) inhibited by addition of a neutralizing mAb against uPAR or an uPA inhibitor. Silencing of uPAR also abrogated the response to uPA and decreased metastasis in an orthotopic model, indicating that uPA/uPAR signaling acts in a positive feedback loop in the regulation of inherent OS metastasis. To investigate whether BMC could also be signaling through uPA/uPAR, we performed a comparative transcriptomic analysis of metastatic and non-metastatic OS cell lines before and after treatment with BMC conditioned medium, and found that uPA was the most significantly (FC = 7.97, B = 18.82) upregulated gene after BMC treatment. Moreover, immunohistochemistry on femurs of mice bearing OS tumours showed high expression of uPA in the bone marrow as well as in the leading edges of the tumour. In addition, BMC conditioned medium containing high levels of secreted uPA also significantly increased metastatic OS cell migration. Our data indicate that increased uPA gene expression induced by BMC could contribute to enhanced secretion of uPA by OS cells, which in turn could augment signaling through uPAR to increase migration. In addition, BMC secrete uPA into the microenvironment to further increase migration of OS tumour cells in close proximity. Finally, we used a therapeutic inhibitor of uPA in an orthotopic mouse model of OS. The uPA inhibitor reduced metastasis significantly (P = 0.0004) in the treated group. This opens the possibility that uPA inhibitors, which are already in clinical trials for a number of cancers, may also be a useful therapeutic in the treatment for OS metastasis.

Citation Format: Liliana B. Endo-Munoz, Na Cai, Andrew Cumming, Dorothy Loo, Michelle Hill, Pamela Mukhopadhyay, Nicholas A. Saunders. An inhibitor of uPA reduces osteosarcoma metastasis by blocking signaling in tumour cells and the bone marrow microenvironment . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3948. doi:10.1158/1538-7445.AM2013-3948

Paradoxical role of autophagy in the dysplastic and tumor-forming stages of hepatocarcinoma development in rats

Many reports have shown that autophagy has a role as both a promoter and inhibitor in tumor development. However, the mechanism of this paradox is unknown. Tumor development is a multistep process. Therefore, we investigated whether the role of autophagy in hepatocarcinoma formation depended on the stage of tumor development. Based on our results, autophagy inhibition by chloroquine had a tumor-promotive effect in the rat model with N-diethylnitrosamine-induced hepatocarcinogenesis in its dysplastic stage (Ds) and a tumor-suppressive effect in its tumor-forming stage (Ts). In the Ds, autophagy inhibition enhanced cell proliferation, DNA damage and inflammatory cytokines expression in liver. These changes were dependent on the upregulation of reactive oxygen species (ROS) that was resulted from autophagy inhibition, and ultimately accelerated the process of hepatocarcinogenesis. However, in the Ts, autophagy inhibition restrained tumor formation by decreasing tumor cell survival and proliferation. In this stage, autophagy inhibition led to excessive ROS accumulation in the tumor, which promoted cell apoptosis, and prominently suppressed tumor cell metabolism. Taken together, our data suggested that autophagy suppressed hepatocarcinogenesis in the Ds by protecting normal cell stability and promoted hepatocarcinogenesis in the Ts by supporting tumor cells growth. Autophagy always had a role as a protector throughout the process of hepatocarcinoma development.

The microRNA-302-367 cluster suppresses the proliferation of cervical carcinoma cells through the novel target AKT1

The miR-302-367 cluster is specifically expressed in human embryonic stem cells and has been shown to convert human somatic cells into induced pluripotent stem cells. Here, we investigated the role of the miR-302-367 cluster in cervical carcinoma. The cluster was not endogenously expressed in cervical cancer cells, and its ectopic expression did not reprogram the cervical cancer cells to an embryonic stem cell-like state. However, ectopic expression of the miR-302-367 cluster in HeLa and SiHa cervical cancer cells inhibited cell proliferation and tumor formation by blocking the G1/S cell cycle transition. We identified a new cell cycle regulatory pathway in which the miR-302-367 cluster directly down-regulated both cyclin D1 and AKT1 and indirectly up-regulated p27(Kip1) and p21(Cip1), leading to the suppression of cervical cancer cell proliferation. Our findings suggest that the miR-302-367 cluster may be used as a therapeutic reagent for the treatment of cervical carcinoma.

PI3K/AKT/mTOR signaling pathway inhibitors in proliferation of retinal pigment epithelial cells

AIM

To determine whether the PI3K/AKT/mTOR pathway is activated in proliferative vitreoretinopathy (PVR) in homo-sapiens.

METHODS

The retina of controls and patients with PVR were collected and their levels of PI3K, phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP-1 were determined by Western blot. The cultured human retinal pigment epithelial cell line D407 was treated with a specific mTOR inhibitor, rapamycin (RAPA) or a PI3K inhibitor, LY294002, of various concentrations and durations. Cell morphology was observed by phase contrast microscopy and the proliferation and apoptosis of treated cells were determined by MTT assay and flow cytometry.

RESULTS

Levels of PI3K, phospho-AKT, phospho-mTOR, phospho-P70S6K and phospho-4EBP1 was increased in the retina in PVR (P<0.05). In D407 cells, both RAPA and LY294002 significantly inhibited cell proliferation and cell cycle progression, and promoted apoptosis (P <0.05); morphologically, the cells became smaller. Both RAPA and LY294002 reduced levels of phospho-AKT, phospho-mTOR, phospho-p70S6k and phospho-4EBP1 expression (P <0.05). RAPA, but not LY294002, had no significant effect on PI3K expression.

CONCLUSION

PI3K/AKT/mTOR signaling pathway is highly activated in the retinal pigment epithelial cells of PVR. The inhibitors of PI3K/AKT/mTOR signaling pathway, RAPA and LY294002, could inhibited the PI3K/AKT/mTOR signaling pathway by reducing the levels of phosphorylation of mTOR pathway components.

Time-varying latent effect model for longitudinal data with informative observation times

In analysis of longitudinal data, it is not uncommon that observation times of repeated measurements are subject-specific and correlated with underlying longitudinal outcomes. Taking account of the dependence between observation times and longitudinal outcomes is critical under these situations to assure the validity of statistical inference. In this article, we propose a flexible joint model for longitudinal data analysis in the presence of informative observation times. In particular, the new procedure considers the shared random-effect model and assumes a time-varying coefficient for the latent variable, allowing a flexible way of modeling longitudinal outcomes while adjusting their association with observation times. Estimating equations are developed for parameter estimation. We show that the resulting estimators are consistent and asymptotically normal, with variance-covariance matrix that has a closed form and can be consistently estimated by the usual plug-in method. One additional advantage of the procedure is that it provides a unified framework to test whether the effect of the latent variable is zero, constant, or time-varying. Simulation studies show that the proposed approach is appropriate for practical use. An application to a bladder cancer data is also given to illustrate the methodology.

[Comparative study on application of Duo positive airway pressure and continuous positive airway pressure in preterm neonates with respiratory distress syndrome]

OBJECTIVE

To determine whether early application of Duo positive airway pressure (DuoPAP), in comparison with nasal continuous positive airway pressure (NCPAP), can reduce the need for endotracheal intubation and mechanical ventilation and decrease the incidence of bronchopulmonary dysplasia (BPD) in preterm neonates with respiratory distress syndrome (RDS).

METHODS

In a single-center, randomized controlled trial, preterm neonates (gestational ages 30-35 weeks) with RDS were randomly assigned to receive DuoPAP (n=34) or NCPAP (n=33) within 6 hours of birth. If the two noninvasive ventilations were not effective, endotracheal intubation and mechanical ventilation were used, and pulmonary surfactant was administered as rescue therapy. The total invasive respiratory support rate and incidence of BPD within 24, 48 and 72 hours of birth were observed. The two groups were compared in terms of PaCO2, PaO2 and oxygenation index (OI) at 1, 12, 24, 48 and 72 hours after using the noninvasive respiratory support.

RESULTS

The total invasive respiratory support rates within 48 and 72 hours after birth were significantly lower in the DuoPAP group than in the NCPAP group (P<0.05). There was no difference in the incidence of BPD between the two groups (P>0.05). The OI in the DuoPAP group was significantly higher than in the NCPAP group at 1, 12, 24, 48 and 72 hours after noninlasive respiratory support (P<0.05). The DuoPAP group showed significantly lower PaCO2 than the NCPAP group at 1, 12, and 24 hours after noninvasive respiratory support (P<0.05). PaO2 was significantly higher in the DuoPAP group than in the NCPAP group at 1 and 12 hours after noninvasive respiratory support (P<0.05).

CONCLUSIONS

Compared with NCPAP, early application of DuoPAP can decrease the need for endotracheal intubation and mechanical ventilation in preterm neonates with RDS, showing promise for broad use.

Expressions of survivin and vascular endothelial growth factor in a Murine model of proliferative retinopathy

AIM

To examine the expression of survivin and vascular endothelial growth factor(VEGF) during the development of retinal neovascularization (NV) in a mouse model.

METHODS

A well-characterized murine model of retinal NV was used to study the expression of survivin and VEGF. NV of the retina was induced in mice by exposure to 75% O(2) from postnatal day P7 to P12, followed by return to room air from P12 to P17. Expression of survivin and VEGF protein was analyzed by Immunohistochemistry. In addition, mouse model of proliferative retinopathy was analyzed by retinal fluorescein angiography and quantification analysis.

RESULTS

The normal mice had both superfiekal and deep vascular layers that extended from the optic nerve to the periphery. In intraocular pressure(IOP) mice were characterized by represent a typical pattern of pathological retinal NV. There are less or little nuclei of new vessels vascular endothelial cell breaking through the inner retinal than in retinopathy of prematurity (ROP) mice, large clusters of blood vessels were adherent to the internal limiting membrane(ILM) (0.27±0.20 vs 23.38±1.027, t=9.454, P<0.001). During the angiogenic period from P13 to P17, survivin and VEGF protein expression increased in experimental retinas compared with control samples(2.56±0.46 vs 3.34±0.40, t=17.43, P<0.01: 2.18±0.75 vs 4.34±0.25, t=19.61, P<0.01). Protein levels of VEGF and survivn has significantly positive correlation (P<0.05, r=0.411).

CONCLUSION

Correlation was made at the protein levels of survivin expression compared with that of VEGF in a murine model of retinal NV, which suggests a temporal role for survivin and VEGF in new vessel formation in response to hypoxic stimulation.

Long-term protective effects of methamphetamine preconditioning against single-day methamphetamine toxic challenges

Methamphetamine (METH) use is associated with neurotoxic effects which include decreased levels of dopamine (DA), serotonin (5-HT) and their metabolites in the brain. We have shown that escalating METH dosing can protect against METH induced neurotoxicity in rats sacrificed within 24 hours after a toxic METH challenge. The purpose of the current study was to investigate if the protective effects of METH persisted for a long period of time. We also tested if a second challenge with a toxic dose of METH would cause further damage to monoaminergic terminals. Saline-pretreated rats showed significant METH-induced decreases in striatal DA and 5-HT levels in rats sacrificed 2 weeks after the challenge. Rats that received two METH challenges showed no further decreases in striatal DA or 5-HT levels in comparison to the single METH challenge. In contrast, METH-pretreated rats showed significant protection against METH-induced striatal DA and 5-HT depletion. In addition, the METH challenge causes substantial decreases in cortical 5-HT levels which were not further potentiated by a second drug challenge. METH preconditioning provided almost complete protection against METH -induced 5-HT depletion. These results are consistent with the idea that METH pretreatment renders the brain refractory to METH-induced degeneration of brain monoaminergic systems.