Magnetic and upconverted luminescent properties of multifunctional lanthanide doped cubic KGdF4 nanocrystals

Lanthanide (Ln3+) doped KGdF4 (Ln=Yb3+, Er3+, Ho3+, Tm3+) nanocrystals with a mean diameter of approximately 12 nm were synthesized by a hydrothermal method using oleic acid as a stabilizing agent at 180 °C. The nanocrystals crystallize in the cubic phase as α-NaGdF4. When excited by a 980 nm laser, these Ln3+ doped nanocrystals exhibit multicolor up-conversion (UC) emissions in red, yellow, blue and white. The calculated color coordinates demonstrate that white UC emission (CIE-X=0.352, CIE-Y=0.347) can be obtained by varying the dopant concentrations in the Yb3+/Ho3+/Tm3+ triply-doped nanocrystals to yield different RGB emission intensities. The measured field dependence of magnetization (M-H curves) of the KGdF4 nanocrystals shows their paramagnetic characteristics that can be ascribed to the non-interacting localized nature of the magnetic moment of Gd3+ ions. Moreover, low temperature thermal treatment can enhance UC properties, magnetization and magnetic mass susceptibility of Ln3+ doped KGdF4 nanocrystals. The multifunctional Ln3+ doped KGdF4 nanocrystals have potential applications in color displays, bioseparation, and optical-magnetic dual modal nanoprobes in biomedical imaging.

Nociceptive afferent activity alters the SI RA neuron response to mechanical skin stimulation

Procedures that reliably evoke cutaneous pain in humans (i.e., 5-7 s skin contact with a 47-51 °C probe, intradermal algogen injection) are shown to decrease the mean spike firing rate (MFR) and degree to which the rapidly adapting (RA) neurons in areas 3b/1 of squirrel monkey primary somatosensory cortex (SI) entrain to a 25-Hz stimulus to the receptive field center (RF(center)) when stimulus amplitude is "near-threshold" (i.e., 10-50 μm). In contrast, RA neuron MFR and entrainment are either unaffected or enhanced by 47-51 °C contact or intradermal algogen injection when the amplitude of 25-Hz stimulation is 100-200 μm (suprathreshold). The results are attributed to an "activity dependence" of γ-aminobutyric acid (GABA) action on the GABA(A) receptors of RA neurons. The nociceptive afferent drive triggered by skin contact with a 47-51 °C probe or intradermal algogen is proposed to activate nociresponsive neurons in area 3a which, via corticocortical connections, leads to the release of GABA in areas 3b/1. It is hypothesized that GABA is hyperpolarizing/inhibitory and suppresses stimulus-evoked RA neuron MFR and entrainment whenever RA neuron activity is low (as when the RF(center) stimulus is weak/near-threshold) but is depolarizing/excitatory and augments MFR and entrainment when RA neuron activity is high (when the stimulus is strong/suprathreshold).

Endovascular treatment for cerebral aneurysms using stents

Endovascular stent placement combined with coil embolization is an established procedure for the treatment of intracranial aneurysms. We describe lesion outcome using stents for the treatment of intracranial aneurysms. Sixty-nine patients (30 females and 39 males; age range 12-78 years) treated with stent placement at Beijing Tiantan Hospital over a six-year period. Seventy- six cerebral aneurysms were encountered and 74 lesions were treated with 79 stents. Outcome was evaluated using the Glasgow Outcome Scale (GOS) score during a mean follow-up period of 32 months. Of the 74 stented aneurysms, 34 (45.9%) were located in the anterior circulation and 40 (54.1%) in the posterior circulation. Forty-eight (64.9%) aneurysms were small and 26 (35.1%) were large or giant. In 67 (90.5%) aneurysms embolization was completed by packing the aneurysm sac with platinum coils. In five small fusiform and four saccular aneurysms, the stent was used alone. Six procedure-related complications were observed and a cause of death in 7.2% of the patients. Follow-up angiography obtained at three months to one year in 68 (91.9%) aneurysms demonstrated complete occlusion in 43 aneurysms with a progressive thrombosis rate of 19.4% (six out of 31 aneurysms). Aneurysm recurrence occurred in four (5.8%) patients, three were treated with coil embolization and one with placement of another stent. Overall long-term outcome was good (GOS Score 4 or 5) in 92.8%, and fatal (GOS Score 1) in 7.2% of the patients. Intracranial stents can be a useful addition to coil embolization for complex broad-based aneurysms. Favorable overall long-term outcome can be achieved in 92.8% of patients when using endovascular stent placement techniques.

Downregulation of caspase-9 is a frequent event in patients with stage II colorectal cancer and correlates with poor clinical outcome

OBJECTIVE

 To evaluate the clinical significance of caspase-9 mRNA expression and investigate its prognostic value in stage II colorectal cancer.

METHOD

Quantitative real-time RT-PCR was used to analyse caspase-9 mRNA expression in cancer tissue and corresponding normal mucosa from 120 patients.

RESULTS

Compared with normal mucosa, the expression of caspase-9 mRNA was found to be downregulated in cancer tissue (P = 0.001). Poorly differentiated cancer showed lower mRNA expression than cancer with greater differentiation (P = 0.031). The Kaplan-Meier survival analysis demonstrated that patients with downregulated caspase-9 showed a worse overall survival (P = 0.012) and disease-free survival (P = 0.022). Cox's proportional hazards regression model confirmed that expression of caspase-9 was the strongest prognostic factor in stage II colorectal cancer.

CONCLUSION

The mRNA expression of caspase-9 can be used as an independent prognostic factor for patients with stage II colorectal cancer.

Irbesartan treatment up-regulates hepatic expression of PPARalpha and its target genes in obese Koletsky (fa(k)/fa(k)) rats: a link to amelioration of hypertriglyceridaemia

BACKGROUND AND PURPOSE

Hypertriglyceridaemia is associated with an increased risk of cardiovascular disease. Irbesartan, a well-established angiotensin II type 1 receptor (AT(1)) blocker, improves hypertriglyceridaemia in rodents and humans but the underlying mechanism of action is unclear.

EXPERIMENTAL APPROACH

Male obese Koletsky (fa(k)/fa(k)) rats, which exhibit spontaneous hypertension and metabolic abnormalities, received irbesartan (40 mg x kg(-1) x day(-1)) or vehicle by oral gavage over 7 weeks. Adipocyte-derived hormones in plasma were measured by ELISA. Gene expression in liver and other tissues was assessed by real-time PCR and Western immunoblotting.

KEY RESULTS

In Koletsky (fa(k)/fa(k)) rats irbesartan lowered plasma concentrations of triglycerides and non-esterified fatty acids, and decreased plasma insulin concentrations and the homeostasis model assessment of insulin resistance index. However, this treatment did not affect food intake, body weight, epididymal white adipose tissue weight, adipocyte size and plasma leptin concentrations, although plasma adiponectin was decreased. Irbesartan up-regulated hepatic expression of mRNAs corresponding to peroxisome proliferator-activated receptor (PPAR)alpha and its target genes (carnitine palmitoyltransferase-1a, acyl-CoA oxidase and fatty acid translocase/CD36) that mediate hepatic fatty acid uptake and oxidation; the increase in hepatic PPARalpha expression was confirmed at the protein level. In contrast, irbesartan did not affect expression of adipose PPARgamma and its downstream genes or hepatic genes that mediate fatty acid synthesis.

CONCLUSIONS AND IMPLICATIONS

These findings demonstrate that irbesartan treatment up-regulates PPARalpha and several target genes in liver of obese spontaneously hypertensive Koletsky (fa(k)/fa(k)) rats and offers a novel insight into the lipid-lowering mechanism of irbesartan.

Antigen sampling on the Peyer's patches in a murine small bowel transplantation model

AIM

This study investigated changes in the mucosal barrier of transplanted intestines with particular emphasis on antigen sampling by Peyer's patches (PPs).

METHODS

Heterotopic small bowel transplantation (SBTx) was performed as described previously. C57BL/6 mice were used as donors and BALB/c (allogeneic) or C57BL/6 mice (syngeneic) as recipients. Tacrolimus (FK506) or saline control was administered to the recipients for 2 weeks. Four groups included in this study were: syngeneic with or without immunosuppression (SYN and SYN + FK506, respectively) and allogeneic with or without immunosuppression (ALLO and ALLO + FK506, respectively). Animals were sacrificed weekly after SBTx to evaluate microfold (M) cells within PPs and for routine histology. By the third postoperative week, recipients were subjected to an intestine loop model to examine the uptake of microbeads by M cells as well as expression of Toll-like receptor 2 (TLR2) protein in the PPs with or without a TLR2 agonist challenge. We also measured occludin expression on follicle-associated epithelium (FAE) of PPs in the grafts.

RESULTS

Transportation of microbeads through the PPs of the grafts increased in the ALLO + FK506 group compared with that in the SYN or SYN + FK506 group. This finding was accompanied by increased expression of TLR2 in the PPs and a gradually increased number of M cells following SBTx. However, occludin expression patterns on the FAE of the PPs in the grafts were similar among SYN, SYN + FK506, and ALLO + FK506 groups. Nevertheless, as transportation of microbeads and TLR2 expression in the PPs of the grafts was enhanced once exposed to Pam3Cys-SKKKK, similar results were not seen in the ALLO + FK506 group.

CONCLUSIONS

Our study revealed that the mucosal barrier of intestinal grafts is altered under alloreactivity as evidenced by enhanced antigen sampling. Such a change may provide a pathway for translocation of microorganisms in the lumen.

Effects of the composition of standard reference material on the accuracy of determinations of 210Pb and 137Cs in soils with gamma spectrometry

The effect of the composition of the used standard reference material (SRM) on results of determination of fallout radionuclides in soil samples was studied. Using five soil types as SRMs, we measured the specific activity of (210)Pb and (137)Cs in six target samples of Chestnut soil. It was observed that the determination of the (210)Pb activity in the samples depended on the chemical composition of SRMs used to create the efficiency curves. Thus, using SRMs similar in chemical composition to the target samples should improve accuracy in the determination of (210)Pb in environmental samples.

Periodontal pathogen Aggregatibacter actinomycetemcomitans LPS induces mitochondria-dependent-apoptosis in human placental trophoblasts

OBJECTIVE

Increasing evidence suggests an association between periodontal disease and low birthweight (LBW); however the underlying molecular mechanisms are yet to be fully elucidated. In this study, we performed a microarray analysis to observe the human placental trophoblast-like BeWo cells response to lipopolysaccharide (LPS) from periodontopathogen Aggregatibacter actinomycetemcomitans (Aa), in order to investigate the molecular basis of mechanisms for periodontitis-associated LBW. In vivo pregnant rats were also used to confirm the in vitro results.

STUDY DESIGN

The effects of Aa-LPS on cultured human placental trophoblast-like BeWo cells were studied using a DNA microarray, Ingenuity Pathway Analysis, real-time PCR and poly-caspase staining. The in vivo effects of Aa-LPS in pregnant rats were examined using TUNEL assays.

RESULTS

In BeWo cells, Aa-LPS increased levels of cytochrome c, caspase 2, caspase 3, caspase 9 and BCL2-antagonist/killer 1 mRNA, decreased those of B-cell CLL/lymphoma 2, BCL2-like 1 and catalase mRNA and increased poly-caspase activity, all of which are consistent with activation of the mitochondria-dependent apoptotic pathway. TUNEL assays confirmed the increased incidence of apoptosis in placentas of Aa-LPS-treated rats (p < 0.001).

CONCLUSION

Aa-LPS induces apoptosis in human trophoblasts via the mitochondria-dependent pathway, and this effect may contribute to the pathogenesis of periodontitis-associated LBW.

Measurement of the bottom quark contribution to nonphotonic electron production in p + p collisions at √s=200 GeV

The contribution of B meson decays to nonphotonic electrons, which are mainly produced by the semileptonic decays of heavy-flavor mesons, in p + p collisions at √s=200  GeV has been measured using azimuthal correlations between nonphotonic electrons and hadrons. The extracted B decay contribution is approximately 50% at a transverse momentum of pT≥5  GeV/c. These measurements constrain the nuclear modification factor for electrons from B and D meson decays. The result indicates that B meson production in heavy ion collisions is also suppressed at high pT.

Inhibition of cerebellar granule cell turning by alcohol

Ectopic neurons are often found in the brains of fetal alcohol spectrum disorders (FASD) and fetal alcohol syndrome (FAS) patients, suggesting that alcohol exposure impairs neuronal cell migration. Although it has been reported that alcohol decreases the speed of neuronal cell migration, little is known about whether alcohol also affects the turning of neurons. Here we show that ethanol exposure inhibits the turning of cerebellar granule cells in vivo and in vitro. First, in vivo studies using P10 mice demonstrated that a single intraperitoneal injection of ethanol not only reduces the number of turning granule cells but also alters the mode of turning at the EGL-ML border of the cerebellum. Second, in vitro analysis using microexplant cultures of P0-P3 mouse cerebella revealed that ethanol directly reduces the frequency of spontaneous granule cell turning in a dose-dependent manner. Third, the action of ethanol on the frequency of granule cell turning was significantly ameliorated by stimulating Ca(2+) and cGMP signaling or by inhibiting cAMP signaling. Taken together, these results indicate that ethanol affects the frequency and mode of cerebellar granule cell turning through alteration of the Ca(2+) and cyclic nucleotide signaling pathways, suggesting that the abnormal allocation of neurons found in the brains of FASD and FSA patients results, at least in part, from impaired turning of immature neurons by alcohol.

p85α mediates p53 K370 acetylation by p300 and regulates its promoter-specific transactivity in the cellular UVB response

Inducible acetylation of p53 at lysine residues has a great impact on regulating the transactivation of this protein, which is associated with cell growth arrest and/or apoptosis under various stress conditions. However, the factor(s) for regulating p53 acetylation remains largely unknown. In the current study, we have shown that p85α, the regulatory subunit of phosphatidylinositol-3-kinase, has a critical role in mediating p53 acetylation and promoter-specific transactivation in the ultraviolet B (UVB) response. Depletion of p85α in mouse embryonic fibroblasts significantly impairs UVB-induced apoptosis, as well as p53 transactivation and acetylation at Lys370 (Lys373 of human p53); however, the accumulation, nuclear translocation and phosphorylation of p53 are not affected. Interestingly, p85α binds to p300, promotes the p300-p53 interaction and the subsequent recruitment of the p53/p300 complex to the promoter region of the specific p53 target gene in response to UVB irradiation. Moreover, ablation of p53 acetylation at Lys370 by site-directed mutagenesis dramatically suppresses UVB-induced expression of the specific p53-responsive gene as well as cell apoptosis. Therefore, we conclude that p85α is a novel regulator of p53-mediated response under certain stress conditions, and targeting the p85α-dependent p53 pathway may be promising for cancer therapy.

Cellular immune responses to recurring influenza strains have limited boosting ability and limited cross-reactivity to other strains

Influenza vaccine provides protection against infection with matched strains, and this protection correlates with serum antibody titres. In addition to antibodies, influenza-specific CD8+ T-lymphocyte responses are important in decreasing disease severity and facilitating viral clearance. Because this response is directed at internal, relatively conserved antigens, it affords some cross-protection within a given subtype of influenza virus. With the possibility of a broader A(H1N1) Mexico outbreak in the fall of 2009, it appeared worthwhile studying the degree of cellular immune response-mediated cross-reactivity among influenza virus isolates. The composition of the 2006-2007 influenza vaccine included the A/New Caledonia/20/1999 strain (comprising a virus that has been circulating, and was included in vaccine preparations, for 6-7 years) and two strains not previously included (Wisconsin and Malaysia). This combination afforded us the opportunity to determine the degree of cross-reactive cellular immunity after exposure to new viral strains. We analysed the antibody responses and the phenotype and function of the T cell response to vaccine components. The results obtained show that antibody responses to A/New-Caledonia were already high and vaccination did not increase antibody or cytotoxic T lymphocyte responses. These data suggest that repeated exposure to the same influenza stain results in limited boosting of humoral and cellular immune responses.

A comparison of batch effect removal methods for enhancement of prediction performance using MAQC-II microarray gene expression data

Batch effects are the systematic non-biological differences between batches (groups) of samples in microarray experiments due to various causes such as differences in sample preparation and hybridization protocols. Previous work focused mainly on the development of methods for effective batch effects removal. However, their impact on cross-batch prediction performance, which is one of the most important goals in microarray-based applications, has not been addressed. This paper uses a broad selection of data sets from the Microarray Quality Control Phase II (MAQC-II) effort, generated on three microarray platforms with different causes of batch effects to assess the efficacy of their removal. Two data sets from cross-tissue and cross-platform experiments are also included. Of the 120 cases studied using Support vector machines (SVM) and K nearest neighbors (KNN) as classifiers and Matthews correlation coefficient (MCC) as performance metric, we find that Ratio-G, Ratio-A, EJLR, mean-centering and standardization methods perform better or equivalent to no batch effect removal in 89, 85, 83, 79 and 75% of the cases, respectively, suggesting that the application of these methods is generally advisable and ratio-based methods are preferred.