Serum Cyr61 as a potential biomarker for diagnosis of colorectal cancer

PURPOSE

To determine the sensitivity and specificity of serum Cyr61 as a potential biomarker for the diagnosis of colorectal cancer (CRC) and to assess the association between serum Cyr61 level and CRC clinicopathological status.

METHODS

We used an enzyme-linked immunosorbent assay to measure serum Cyr61 in patients with CRC, patients with colorectal adenomas, and healthy controls. We also analyzed the relationship between serum Cyr61 and clinicopathological features of CRC patients. The levels of serum carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were quantified using the Roche Cobas 6000 Analyzer. The sensitivity and specificity of Cyr61, CEA, CA19-9 and CEA + CA19-9 were evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

The serum level of Cyr61 was significantly increased in CRC patients compared with colorectal adenoma patients and healthy controls (p < 0.001). Furthermore, the area under the ROC curve for Cyr61 was 0.935 (95 % confidence interval 0.902-0.968), higher than that for CEA + CA19-9 (0.827, 95 % confidence interval: 0.783-0.871). Use of a Cyr61 cutoff value of 92.0 pg/mL allowed distinguishing CRC patients and healthy controls with a sensitivity of 83 % and a specificity of 97 %. Among CRC patients, an elevated level of serum Cyr61 was significantly associated with more advanced TNM stage (p < 0.0042), lymph node metastasis (p < 0.0088), and vascular invasion (p = 0.0027).

CONCLUSION

Cyr61 has potential as a serum biomarker for the diagnosis of CRC and for assessment of the clinicopathological status of CRC.

Integrated Microfluidic Aptasensor for Mass Spectrometric Detection of Vasopressin in Human Plasma Ultrafiltrate

We present a microfluidic aptamer-based biosensor for detection of low-molecular-weight biomarkers in patient samples. Using a microfluidic device that integrates aptamer-based specific analyte extraction, isocratic elution, and detection by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, we demonstrate rapid, sensitive and label-free detection of arginine vasopressin (AVP) in human plasma ultrafiltrate. AVP molecules in complex matrices are specifically captured by an aptamer that is immobilized on microbeads via affinity binding in a microchamber. After the removal of unbound, contaminating molecules through washing, aptamer-AVP complexes are thermally disrupted via on-chip temperature control. Released AVP molecules are eluted with purified water and transferred to a separate microchamber, and deposited onto a single spot on a MALDI plate via repeated, piezoelectrically actuated ejection, which enriches AVP molecules over the spot area. This integrated on-chip sample processing enables the quantitative detection of low-abundance AVP by MALDI-TOF mass spectrometry in a rapid and label-free manner. Our experimental results show the detection of AVP in human plasma ultrafiltrate as low as physiologically relevant picomolar concentrations via aptamer-based selective preconcentration, demonstrating the potential of our approach as a rapid (~ 1hr), sensitive clinical AVP assay.

[Comparison of balloon catheter dilatation and silicon intubation as the secondary treatment for congenital nasolacrimal duct obstruction after failed primary probing]

OBJECTIVE

To determine the success rates and compare the results of balloon catheter dilation and nasolacrimal intubation as treatment for congenital nasolacrimal duct obstruction after failed probing, stratified by category of age and type of obstruction.

METHODS

It was a prospective, randomized, clinical trial that enrolled 189 children (245 eyes) aged between 6 months to 48 months who had a history of failed nasolacrimal duct probing. All eyes underwent either balloon catheter nasolacrimal duct dilation or nasolacrimal duct intubation randomly. The eyes were divided into 2 age categories: category 1 (6-24 months) and category 2 (>24 months) and into 2 types of obstructions: simple obstruction and complex obstruction. Treatment success was defined as absence of epiphora, mucous discharge, or increased lacrimal lake at the outcome visit 6 months after surgery. Complications were also compared.

RESULTS

In 124 eyes treated with balloon catheter dilatation, 112 were successful (90.3%) comparing with 106 successful eyes (87.6%) in 121 eyes treated with nasolacrimal duct intubation. The risk ratio for success between intubation and balloon dilation was 0.971, and the 95% confidence interval was 0.95-1.22. Within each age category, the success rate varied but did not show significant difference: In those under 24 months, success rate was 89.7% in 97 eyes treated with intubation, and 91.9% in 99 eyes treated with balloon dilation (RR, 0.976; 95% CI, 0.590-0.956). In those above 24 months, success rate was 79.1% in 24 eyes treated with intubation, and 84.0% in 25 eyes treated with balloon dilation (RR, 0.942; 95%CI, 0.813-1.387). In the group of simple obstruction, success rate was 96.5% in 87 eyes treated with intubation, and 93.1% in 88 eyes treated with balloon dilation (RR, 1.036; 95% CI, 0.967-1.105). In the group of complex obstruction, Success rate was 64.7% in 34 eyes treated with intubation, and 86.1% in 36 eyes treated with balloon dilation. The success rate of balloon dilatation showed slightly higher than that of intubation (RR, 0.751; 95% CI, 0.590-0.956). There were 59 eyes showed complications in intubation group, while only 2 eyes in balloon dilation group.

CONCLUSIONS

Both balloon catheter dilation and nasolacrimal duct intubation could alleviate the clinical signs of persistent nasolacrimal duct obstruction with a similar percentage of patients. In the complex obstruction group, balloon catheter dilation showed better efficacy than nasolacrimal duct intubation.

Dynamic Modeling of a Laminated Composite- Material Flexible Robot Arm Made of Short Beams

High-precision assembly tasks are often performed by compact industrial robots with small work envelopes. The end-effector positional accuracy of compact robots can be accurately predicted by considering the links of the robot arm as short beams. In this study, a general procedure to derive a dynamic model for a revolute flexible robot arm, which takes into consideration the rotary inertia and shear deformation effects, is presented. Only the last link of the arm is considered to be flexible and assumed to be fabri cated from laminated composite materials.

Hamilton's principle is used to derive the equations of motion. A displacement finite element model based on the Timoshenko beam theory is implemented to approximate the solution. The digital simulation studies predict the deflections at the end effector and examine the combined effects of rotary inertia and shear deformation. Further more, the improvement in the dynamic response of the robot arm resulting from the fabrication of the manipula tor from laminated composite materials is demonstrated.

The Function and Regulation of BMP6 in Various Kinds of Stem Cells

Stem cells, by definition, are the primitive cells that have the potential of both self-renewal and differentiation into a number of mature and functional cells, and thus they have great applications in cell therapy and tissue engineering for regenerative medicine. Bone morphogenetic protein 6 (BMP6) belongs to transforming growth factor β(TGF-β) superfamily. The fate determinations of stem cells require complex regulatory networks that involve BMP6 signaling pathway. Recent studies have demonstrated that BMP6 plays crucial roles in controlling the self-renewal and differentiation of stem cells. In this review, we address the expression, function and regulation of BMP6 in various kinds of stem cells, with focus on mesenchymal stem cells (MSCs), germline stem cells (GSCs), hematopoietic stem cells (HSCs), and neural stem cells (NSCs). Notably, there are distinct effects of BMP6 on promoting self-renewal and differentiation of these stem cells. We also discuss the involement of BMP6 in diseases, including leukemia, astrocytic glioma, and Alzheimer's disease, and the therapy of these diseases via gene targeting. We further highlight certain issues for further investigation on the regulation and function of BMP6 in stem cells. Significantly, a thorough understanding of BMP6 regulation on a variety of adult stem cells could make them feasible for applications in both regenerative and reproductive medicine, and it would shed novel insights into the etiology of the diseases and offer new targets for drug design to treat these disorders.

A study on the role of apoptotic human umbilical cord mesenchymal stem cells in bleomycin-induced acute lung injury in rat models

OBJECTIVE

We sought to determine whether normal human umbilical cord mesenchymal stem cells and apoptotic human umbilical cord mesenchymal stem cells play any role in the lung repair following bleomycin-induced lung injury in rat models.

MATERIALS AND METHODS

Umbilical cord mesenchymal stem cells were obtained from the umbilical cord following caesarian section from healthy normal babies. Plasmin deprivation method was used for culture of human umbilical cord mesenchymal stem cells and flow cytometry was used to identify cell surface antigen and activity of stem cells and apoptosis. The animal model of acute lung injury was established by a one-off intratracheal instillation of bleomycin (BLM) (5 mg/kg) and then normal stem cells and apoptotic stem cells were separately injected. Alveolar lavage fluid and lung tissue were collected for further analysis prior to the injury and at days 3, 7, 14 after administration of BLM. The number of neutrophils in the broncho alveolar lavage fluid (BALF) was counted; Bicinchoninic Acid (BCA) method was used for estimation of total protein content in alveolar lavage fluid; biochemical assay was used for estimation of myeloperoxidase (MPO) activity; hematoxylin and eosin (HE) staining of lung tissue was used for histopathology analysis; reverse transcription-polymerase chain reaction (RT-PCR) assay was used for the determination of interferon-gamma (INF-γ) and mRNA changes of interleukin-4 (IL-4) in lung tissue. Enzyme-linked immunosorbent assay (ELISA) was used for the determination of cytokines TNF-α in the lung tissue.

RESULTS

Apoptotic human umbilical cord mesenchymal stem cells were more effective in reducing lung neutrophil infiltration and total protein leakage in rat models of acute lung injury (ALI). There was also an improvement in the degree of vascular permeability, reduction in the level of proinflammatory cytokines, INF-γ gene level and boost in anti-inflammatory cytokine IL-4 levels which also helps in more effectively reducing the degree of injury in ALI.

CONCLUSIONS

Human umbilical cord mesenchymal stem cell transplantation may have a bright future in the clinical setting for the treatment of ALI/acute respiratory distress syndrome (ARDS). Apoptotic human umbilical cord mesenchymal stem cells may have more effective than normal human umbilical cord mesenchymal stem cells in the treatment of acute lung injury.

Bulking agents - an analysis of 500 cases and review of the literature

INTRODUCTION

Stress urinary incontinence (SUI) is common, impacts women's quality of life and generates high costs. Physiotherapy is the first line therapy and if it fails, suburethral slings are currently the gold standard in SUI surgery. Bulking agents injected periurethrally might be a beneficial alternative, but there is a paucity of data on bulking therapy. Aim of the current-study was to analyze the efficacy and safety of bulking agents in the setting of a tertiary referral center prospectively.

MATERIALS AND METHODS

In the last 13 years 514 elderly women with SUI were treated by injection therapy with either collagen, hyaluronic acid, ethylene vinyl alcohol or polyacrylamide hydrogel. Subjective and objective outcomes were recorded at the 12 month post-operative appointment using the King's Health Questionnaire (KHQ) and Visual Analogue Scale (VAS) to describe their incontinence severity, standardized Pad-Test, and urethral pressure profile.

RESULTS

Demographic data were equally distributed in all four groups of agents used. Sixty-one patients were lost to follow-up (10.6%). Statistically significant changes were found for maximum urethral closure pressure (MUCP), pad weight, and VAS before and after bulking for the four agents used. Pad-Test was negative in 73.2% of patients after bulking therapy. Subjective assessment showed improvements in general health and role limitations. The overall complication rate poly- was low for all agents.

CONCLUSIONS

The current study shows an improvement of incontinence after bulking therapy applying subjective and objective outcomes in an elderly population. In contrast to earlier reports, side effects due to injections were few and mild. We can advocate bulking therapy for the.

Pcgf6, a polycomb group protein, regulates mesodermal lineage differentiation in murine ESCs and functions in iPS reprogramming

Polycomb group (PcG) proteins comprise evolutionary conserved factors with essential functions for embryonic development and adult stem cells. PcG proteins constitute two main multiprotein polycomb repressive complexes (PRC1 and PRC2) that operate in a hierarchical manner to silence gene transcription. Functionally distinct PRC1 complexes are defined by Polycomb group RING finger protein (Pcgf) paralogs. So far, six Pcgf paralogs (Pcgf1-6) have been identified as defining components of different PCR1-type complexes. Paralog-specific functions are not well understood. Here, we show that Pcgf6 is the only Pcgf paralog with high expression in undifferentiated embryonic stem cells (ESCs). Upon differentiation Pcgf6 expression declines. Following Pcgf6 kockdown (KD) in ESCs, the expression of pluripotency genes decreased, while mesodermal- and spermatogenesis-specific genes were derepressed. Concomitantly with the elevated expression of mesodermal lineage markers, Pcgf6 KD ESCs showed increased hemangioblastic and hematopoietic activities upon differentiation suggesting a function of Pcgf6 in repressing mesodermal-specific lineage genes. Consistant with a role in pluripotency, Pcgf6 replaced Sox2 in the generation of germline-competent induced pluripotent stem (iPS) cells. Furthermore, Pcgf6 KD in mouse embryonic fibroblasts reduced the formation of ESC-like colonies in OSKM-driven reprogramming. Together, these analyses indicate that Pcgf6 is nonredundantly involved in maintaining the pluripotent nature of ESCs and it functions in iPS reprogramming.

Dynamics of Th17 associating cytokines in Cryptosporidium parvum-infected mice

Cryptosporidium parvum commonly inhabits the intestinal tract of animals and humans and can cause acute watery diarrhea and weight loss. However, host immune responses to Cryptosporidium infections are not fully understood. IL-17 (also called IL-17A) is a pro-inflammatory cytokine of Th17 cells that plays a role in the host response to Cryptosporidium baileyi infection. The present study examined levels of IL-17-specific messenger RNA (mRNA) and Th17 associating cytokines in C. parvum-infected immune-suppressed BALB/c mice using real-time quantitative PCR (qPCR). Levels of IL-17 protein were determined by ELISA. The results showed that levels of IL-17 mRNA and Th17 cell-related cytokines, namely TGF-β, IL-6, STAT-3, RORγt, IL-22, TNF-α, and IL-23, were significantly increased (P < 0.05) in gut-associated lymphoid tissue (GALT) and spleen. IL-17 protein levels in GALT were also significantly increased (P < 0.05) after infection. The present study suggested that Th17 cells play a role in host-C. parvum interaction. These results could inform future studies of the immune response against C. parvum infection in transient immunosuppressed populations.

Emergence of a new GII.17 norovirus variant in patients with acute gastroenteritis in Jiangsu, China, September 2014 to March 2015

From September 2014 to March 2015, 23 outbreaks of norovirus (NoV) acute gastroenteritis occurred in Jiangsu, China. Partial sequencing of the NoV capsid gene suggested that 16 of the 23 outbreaks were related to a new GII.17 variant. This variant was first detected in sporadic specimens in October 2014, and became predominant in February 2015. Analysis of the RNA-dependent RNA polymerase (RdRp), and complete capsid including the protruding domain P2 sequences confirmed this GII.17 variant as distinct from previously identified GII variants.

Development and cross-species transferability of unigene-derived microsatellite markers in an edible oil woody plant, Camellia oleifera (Theaceae)

Camellia oleifera is an important edible oil woody plant in China. Lack of useful molecular markers hinders current genetic research on this tree species. Transcriptome sequencing of developing C. oleifera seeds generated 69,798 unigenes. A total of 6949 putative microsatellites were discovered among 6042 SSR-containing unigenes. Then, 150 simple sequence repeats (SSRs) were evaluated in 20 varieties of C. oleifera. Of these, 52 SSRs revealed polymorphism, with the number of alleles per locus ranging from 2 to 15 and expected heterozygosity values from 0.269 to 0.888. The polymorphic information content varied from 0.32 to 0.897. Cross-species transferability rates in Camellia chekangoleosa and Camellia japonica were 90.4 and 78.8%, respectively. The 52 polymorphic unigene-derived SSR markers serve to enrich existing microsatellite marker resources for C. oleifera and offer potential for applications in genetic diversity evaluation, molecular fingerprinting, and genetic mapping in C. oleifera, C. chekangoleosa, and C. japonica.

Identification of a novel cytochrome P450 gene, CYP321E1 from the diamondback moth, Plutella xylostella (L.) and RNA interference to evaluate its role in chlorantraniliprole resistance

Insect cytochrome P450 monooxygenases (P450s) play an important role in catalysis of many reactions leading to insecticides resistance. Our previous studies on transcriptome analysis of chlorantraniliprole-resistant development in the diamondback moth, Plutella xylostella revealed that up-regulation of cytochrome P450s are one of the main factors leading to the development of chlorantraniliprole resistance. Here, we report for the first time a novel cytochrome P450 gene CYP321E1, which belongs to the cytochrome P450 gene family CYP321. Real-time quantitative PCR (RT-qPCR) analyses indicated that CYP321E1 was expressed at all developmental stages of P. xylostella but was highest in the fourth-instar larvae; furthermore, the relatively high expression was observed in the midgut of the fourth-instar larvae, followed by fat bodies and epidermis. The expression of CYP321E1 in P. xylostella was differentially affected by three representative insecticides, including alphamethrin, abamectin and chlorantraniliprole. Among them, the exposure to chlorantraniliprole resulted in the largest transcript level of this cytochrome P450 gene. The findings suggested potential involvement of CYP321E1 in chlorantraniliprole resistance of P. xylostella. To assess the functional link of CYP321E1 to chlorantraniliprole resistance, RNA interference (RNAi)-mediated gene silencing by double stranded RNA (dsRNA) injecting was used. Results revealed that injection delivery of dsRNA can greatly reduce gene expression after 24 h. As a consequence of RNAi, a significant increment in mortality of larvae injected CYP321E1 dsRNA was observed after 24 h of exposure to chlorantraniliprole. These results strongly support our notion that this novel cytochrome P450 gene plays an important role in chlorantraniliprole detoxification in the diamondback moth and is partly responsible for its resistance.

Reconsideration of the relevance of mild wedge or short vertebral height deformities across a broad age distribution

Based on an evaluation of vertebral fracture prevalence on lateral radiographs across all age groups in a large cohort, mild or wedge-shaped vertebral body changes identified among adults should be managed as osteoporosis or at least considered as a risk factor for osteoporotic fracture, since they are rare among young subjects.

INTRODUCTION

Radiographic assessment of vertebral fractures is limited by the inability to distinguish mild fractures from congenital mild wedge deformities or vertebrae of short vertebral height. We attempted to quantify the expected background prevalence of these deformities by measuring vertebral fracture prevalence across all age groups in a large hospital-based retrospective Chinese cohort.

METHODS

We reviewed eligible lateral chest radiographs from patients admitted to Peking Union Medical College Hospital during 2011 using the Genant semiquantitative method for vertebral fracture assessment (T4-L2). We evaluated fracture prevalence among subjects by sex, 10-year age group, and fracture severity grades subjectively. We further analyzed characteristics of subjects with mild (grade I) fractures to estimate the relative contribution of congenital mild wedge deformities.

RESULTS

A total of 10,720 subjects (5,396 men and 5,324 women) with lateral chest radiographs were evaluated. Subjects ranged in age from 0.5 to 97 years with a mean of 51.8 ± 17.4 years (men 52.8 ± 17.6 years; women 50.8 ± 17.2 years). When stratified by 10-year age groups, the prevalence of vertebral fractures was relatively low until about 40 years of age, after which prevalence increased for both genders. Fractures (13 fractures for 9 males and 6 fractures for 5 females) seen in subjects younger than 40 years of age were almost exclusively mild grade fractures. No fractures were identified in subjects younger than 20 years of age.

CONCLUSIONS

Mild or wedge-shaped vertebral body changes on lateral radiographs are rare among young subjects, indicating that when mild vertebral deformities are found among adults, they are likely to be the product of aging and not congenital variation. Clinically, therefore, mild vertebral body changes should be managed as osteoporosis or at least considered as a risk factor for osteoporotic fracture.

Risk factors for locoregional recurrence after postmastectomy radiotherapy in breast cancer patients with four or more positive axillary lymph nodes

BACKGROUND

We investigated risk factors for locoregional recurrence (lrr) in breast cancer patients with 4 or more positive axillary lymph nodes receiving postmastectomy radiotherapy (pmrt).

METHODS

Medical records (1998-2007) were retrospectively reviewed for the population of interest. The Kaplan-Meier method was used to calculate the survival rate; Cox regression models were used for univariate and multivariate analysis of predictors of breast cancer lrr.

RESULTS

The study enrolled 439 patients. Median duration of follow-up was 54 months. The 5-year rates of locoregional recurrence-free survival (lrrfs), distant metastasis-free survival (dmfs), and breast cancer-specific survival (bcss) were 87.8%, 59.5%, and 70.7% respectively. In patients with lrr and no concomitant metastasis, and in those without lrr, the 5-year rates of dmfs were 21.1% and 65.7% respectively (p < 0.001), and the 5-year rates of bcss were 34.5% and 76.4% respectively (p < 0.001). Univariate analysis showed that menopausal status (p = 0.041), pN stage (p = 0.006), and positivity for her2 [human epidermal growth factor receptor 2 (p = 0.003)] or the triple-negative disease subtype (p < 0.001) were determinants of lrrfs. Multivariate analysis showed that pN3 stage [hazard ratio (hr): 2.241; 95% confidence interval (ci): 1.270 to 3.957; p = 0.005], her2 positivity (hr: 2.705; 95% ci: 1.371 to 5.335; p = 0.004), and triple-negative disease subtype (hr: 4.617; 95% ci: 2.192 to 9.723; p < 0.001) were independent prognostic factors of lrrfs.

CONCLUSIONS

In breast cancer patients with 4 or more positive axillary lymph nodes who undergo pmrt for breast cancer, lrr significantly influences survival. Patients who developed lrr carried a high risk for distant metastasis and death. Pathologic stage (pN3), her2 positivity, and the triple-negative disease subtype are risk factors that significantly influence lrrfs.

Successful transplantation of kidney allografts in sensitized rats after syngeneic hematopoietic stem cell transplantation and fludarabine

Current methods to remove donor-specific HLA antibody (DSA) from sensitized patients remain imperfect. We tested novel approaches to desensitization using an animal model of allogeneic sensitization with skin grafts from dark agouti (DA) to Lewis rats. At the peak IgG alloantibody response we transplanted DA kidneys into nephrectomized Lewis recipients (n = 6) and all died within 10 days from antibody-mediated rejection (AMR). Allogeneic hematopoietic stem cell transplants (HSCT) from DA donors failed to engraft after lethal or sub-lethal irradiation. Sensitized rats given lethal irradiation plus syngeneic green fluorescent protein (GFP) + HSCT had repopulation of blood, spleen, thymus and lymph nodes by GFP+ cells. At 2 months after HSCT, serum DSA levels were reduced 60-70% and DSA (IgG) production in cultured splenocytes was also significantly decreased. However, there was only a modest improvement in graft survival from an average of 6.5 to 13.9 (n = 9) days. Adding seven daily doses of fludarabine to the preconditioning regimen resulted in long-term survival (>90 days) in 7 out of 10 rat kidney allografts. We conclude that syngeneic HSCT performed after preconditioning with irradiation and fludarabine can reduce DSA, prevent DSA rebound and AMR, enabling successful transplantation in animals with strong antibody reactivity to the donor MHC.

Geranylgeranylation signals to the Hippo pathway for breast cancer cell proliferation and migration

Protein geranylgeranylation (GGylation) is an important biochemical process for many cellular signaling molecules. Previous studies have shown that GGylation is essential for cell survival in many types of cancer. However, the molecular mechanism mediating the cell survival effect remains elusive. In this report, we show that the Hippo pathway mediates GGylation-dependent cell proliferation and migration in breast cancer cells. Blockade of GGylation enhanced phosphorylation of Mst1/2 and Lats1, and inhibited YAP and TAZ activity and the Hippo-YAP/TAZ pathway-dependent transcription. The effect of GGylation blockade on inhibition of breast cancer cell proliferation and migration is dependent on the Hippo-YAP/TAZ signaling, in which YAP appears to regulate cell proliferation and TAZ to regulate cell migration. Furthermore, GGylation-dependent cell proliferation is correlated with the activity of YAP/TAZ in breast cancer cells. Finally, Gγ and RhoA are the GGylated proteins that may transduce GGylation signals to the Hippo-YAP/TAZ pathway. Taken together, our studies have demonstrated that the Hippo-YAP/TAZ pathway is essential for GGylation-dependent cancer cell proliferation and migration.

The low-temperature form of calcium gold stannide, CaAuSn

The EuAuGe-type CaAuSn phase has been synthesized and single-crystal X-ray diffraction analysis reveals that it has an orthorhombic symmetry (space group Imm2), with a = 4.5261 (7) Å, b = 7.1356 (11) Å and c = 7.8147 (11) Å. The structure features puckered layers that are connected by homoatomic Au-Au and Sn-Sn interlayer bonds. This structure is one of the two parent structures of its high-temperature polymorph (ca 873 K), which is an intergrowth structure of the EuAuGe- and SrMgSi-type structures in a 2:3 ratio.

Plasmon hybridization in composite nanostructures with tunable resonances and vertex truncation analysis

An Ag/SiO₂/Ag sandwich delta nanostar with three sharp angles (30°) is proposed. The extinction efficiency property with a variation in environment refractive index has been investigated in detail by the finite difference time domain method. The refractive index response sensitivity is 482.67  nm/RIU. And the correlations between resonance wavelengths and thickness of the dielectric layer are also established. It reveals that as the thickness increases, the peak wavelength turns to red shift, and a tunable resonance wavelength is achieved through the thickness adjusting of the SiO₂ layer. The maximum of the electric field enhancement is 833.776 with the thickness of the dielectric layer h=40  nm. Moreover, the influence of the vertex truncation on the extinction spectra and the refractive index sensitivity has also been analyzed.

Allelic differences between Europeans and Chinese for CREB1 SNPs and their implications in gene expression regulation, hippocampal structure and function, and bipolar disorder susceptibility

Bipolar disorder (BD) is a polygenic disorder that shares substantial genetic risk factors with major depressive disorder (MDD). Genetic analyses have reported numerous BD susceptibility genes, while some variants, such as single-nucleotide polymorphisms (SNPs) in CACNA1C have been successfully replicated, many others have not and subsequently their effects on the intermediate phenotypes cannot be verified. Here, we studied the MDD-related gene CREB1 in a set of independent BD sample groups of European ancestry (a total of 64,888 subjects) and identified multiple SNPs significantly associated with BD (the most significant being SNP rs6785[A], P=6.32 × 10(-5), odds ratio (OR)=1.090). Risk SNPs were then subjected to further analyses in healthy Europeans for intermediate phenotypes of BD, including hippocampal volume, hippocampal function and cognitive performance. Our results showed that the risk SNPs were significantly associated with hippocampal volume and hippocampal function, with the risk alleles showing a decreased hippocampal volume and diminished activation of the left hippocampus, adding further evidence for their involvement in BD susceptibility. We also found the risk SNPs were strongly associated with CREB1 expression in lymphoblastoid cells (P<0.005) and the prefrontal cortex (P<1.0 × 10(-6)). Remarkably, population genetic analysis indicated that CREB1 displayed striking differences in allele frequencies between continental populations, and the risk alleles were completely absent in East Asian populations. We demonstrated that the regional prevalence of the CREB1 risk alleles in Europeans is likely caused by genetic hitchhiking due to natural selection acting on a nearby gene. Our results suggest that differential population histories due to natural selection on regional populations may lead to genetic heterogeneity of susceptibility to complex diseases, such as BD, and explain inconsistencies in detecting the genetic markers of these diseases among different ethnic populations.

Neonatal ketamine exposure causes impairment of long-term synaptic plasticity in the anterior cingulate cortex of rats

Ketamine, a dissociative anesthetic most commonly used in many pediatric procedures, has been reported in many animal studies to cause widespread neuroapoptosis in the neonatal brain after exposure in high doses and/or for a prolonged period. This neurodegenerative change occurs most severely in the forebrain including the anterior cingulate cortex (ACC) that is an important brain structure for mediating a variety of cognitive functions. However, it is still unknown whether such apoptotic neurodegeneration early in life would subsequently impair the synaptic plasticity of the ACC later in life. In this study, we performed whole-cell patch-clamp recordings from the ACC brain slices of young adult rats to examine any alterations in long-term synaptic plasticity caused by neonatal ketamine exposure. Ketamine was administered at postnatal day 4-7 (subcutaneous injections, 20mg/kg given six times, once every 2h). At 3-4weeks of age, long-term potentiation (LTP) was induced and recorded by monitoring excitatory postsynaptic currents from ACC slices. We found that the induction of LTP in the ACC was significantly reduced when compared to the control group. The LTP impairment was accompanied by an increase in the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-mediated excitatory synaptic transmission and a decrease in GABA inhibitory synaptic transmission in neurons of the ACC. Thus, our present findings show that neonatal ketamine exposure causes a significant LTP impairment in the ACC. We suggest that the imbalanced synaptic transmission is likely to contribute to ketamine-induced LTP impairment in the ACC.