Functional brain connectivity and cognition: effects of adult age and task demands

Previous neuroimaging research has documented that patterns of intrinsic (resting state) functional connectivity (FC) among brain regions covary with individual measures of cognitive performance. Here, we examined the relation between intrinsic FC and a reaction time (RT) measure of performance, as a function of age group and task demands. We obtained filtered, event-related functional magnetic resonance imaging data, and RT measures of visual search performance, from 21 younger adults (19–29 years old) and 21 healthy, older adults (60–87 years old). Age-related decline occurred in the connectivity strength in multiple brain regions, consistent with previous findings. Among 8 pairs of regions, across somatomotor, orbitofrontal, and subcortical networks, increasing FC was associated with faster responding (lower RT). Relative to younger adults, older adults exhibited a lower strength of this RT-connectivity relation and greater disruption of this relation by a salient but irrelevant display item (color singleton distractor). Age-related differences in the covariation of intrinsic FC and cognitive performance vary as a function of task demands.     

Evaluation of multiplex Polymerase chain reaction utilising multiple targets in Mycobacterium tuberculosis direct test negative but culture positive cases: A potential method for enhancing the diagnosis of tuberculosis

Purpose: To evaluate multiplex Polymerase Chain Reaction (MPCR) utilising multiple targets (IS6110, Protein b [Pab] and MPB64 genes) in Mycobacterium tuberculosis Direct Test (MTD) negative but culture positive cases and comparison of MPCR with Real-Time polymerase chain reaction (RT-PCR) for diagnosis of tuberculosis. Materials and Methods: MPCR was carried out on 28 culture positive sputum samples. Out of 28 culture positive samples, 17 were originally reported, as MTD test negative and 11 were MTD test positive, respectively. The results of MPCR were compared with RT-PCR. To check the specificity of the tests, MPCR and RT-PCR were also evaluated with 16 non-tuberculous mycobacterial (NTM) isolates. Results: Out of 28 culture positive sputum samples, MPCR was positive in all 28/28 samples, whereas RT-PCR was positive in 27/28 samples and MTD test was originally tested positive in six sputum samples and on repeating MTD testing, five more sputum samples were positive and thus total number of MTD positive were 11/28 sputum samples, respectively. All the tests were negative on evaluation with all the 16 NTMs, thus giving specificity of 100% to all the tests; sensitivity of MPCR, RT-PCR and MTD tests were 100%, 96.42% and 39.28%, respectively, in these specifically selected samples. Conclusions: MPCR may be an important tool in the rapid diagnosis of tuberculosis especially in disease endemic, resource limited countries.     

Chemokine programming dendritic cell antigen response: part I – select chemokine programming of antigen uptake even after maturation

Here, we report on the successful programming of dendritic cells (DCs) using selectively applied mixtures of chemokines as a novel protocol for engineering vaccine efficiency. Antigen internalization by DCs is a pivotal step in antigen uptake/presentation for bridging innate and adaptive immunity and in exogenous gene delivery used in vaccine strategies. Contrary to most approaches to improve vaccine efficiency, active enhancement of antigen internalization by DCs as a vaccine strategy has been less studied because DCs naturally down‐regulate antigen internalization upon maturation. Whereas chemokines are mainly known as signal proteins that induce leucocyte chemotaxis, very little research has been carried out to identify any additional effects of chemokines on DCs following maturation. Here, immature DCs are pre‐treated with select chemokines before intentional maturation using lipopolysaccharide (LPS). When pre‐treated with a mixture of CCL3 and CCL19 in a 7 : 3 ratio, then matured with LPS, chemokine pre‐treated DCs exhibited 36% higher antigen uptake capacity than immature DCs and 27% higher antigen‐processing capacity than immature DCs treated only with LPS. Further, CCL3 : CCL19 (7 : 3) pre‐treatment of DCs modulated MHC molecule expression and secretion of various cytokines of DCs. Collectively, DC programming was feasible using a specific chemokine combination and these results provide a novel strategy for enhancing DC‐based vaccine efficiency. In Part II, we report on the phenotype changes and antigen presentation capacity of chemokine pre‐treated murine bone marrow‐derived DCs examined in long‐term co‐culture with antigen‐specific CD4⁺ T cells.     

Cellular uptake,elimination and toxicity of CdSe/ZnS quantum dots in HepG2 cells

In this work, the cellular uptake, elimination and toxicity of CdSe/ZnS QDs in HepG2 cells were comprehensively studied using inductively coupled plasma mass spectrometry (ICP-MS), MTT assay, AO/EB staining, and glutathione level and gene expression analysis. ICP-MS analytical results showed that the uptake efficiency of CdSe QDs by HepG2 cells was lower than that of Cd(II) and Se(IV), and the uptake was dose- and time-dependent. The uptake amount was related to the physicochemical properties of QDs, and NH₂-QDs with smaller size were more easily taken up by cells. In combination with various biochemical methodologies, a systematic and thorough quantitative analysis of the in vitro effects of CdSe/ZnS QDs with different coatings was conducted, along with that of Cd (II) and Se (IV). Although Cd(II) above 8.9 μM exhibited obvious toxicity to the cells, no obvious toxicity of four CdSe/ZnS QDs was observed within the tested concentration range (10–100 nM), most likely due to the protection of the ZnS shell and the PEG coating. From the molecular level's point of view, QDs at concentration of 100 nM exhibit obvious impact on the cells, such as increased gene expression (MT1A and CYP1A1), which was positively correlated with the intracellular concentration of QDs.     

Intestinal mucosa permeability following oral insulin delivery using core shell corona nanolipoparticles

Chitosan nanoparticles (NC) have excellent capacity for protein entrapment, favorable epithelial permeability, and are regarded as promising nanocarriers for oral protein delivery. Herein, we designed and evaluated a class of core shell corona nanolipoparticles (CSC) to further improve the absorption through enhanced intestinal mucus penetration. CSC contains chitosan nanoparticles as a core component and pluronic F127-lipid vesicles as a shell with hydrophilic chain and polyethylene oxide PEO as a corona. These particles were developed by hydration of a dry pluronic F127-lipid film with NC suspensions followed by extrusion. Insulin nested inside CSC was well protected from enzymatic degradation. Compared with NC, CSC exhibited significantly higher efficiency of mucosal penetration and, consequently, higher cellular internalization of insulin in mucus secreting E12 cells. The cellular level of insulin after CSC treatment was 36-fold higher compared to treatment with free insulin, and 10-fold higher compared to NC. CSC significantly facilitated the permeation of insulin across the ileum epithelia, as demonstrated in an ex vivo study and an in vivo absorption study. CSC pharmacological studies in diabetic rats showed that the hypoglycemic effects of orally administrated CSC were 2.5-fold higher compared to NC. In conclusion, CSC is a promising oral protein delivery system to enhance the stability, intestinal mucosal permeability, and oral absorption of insulin.     

Imaging of neurosphere oxygenation with phosphorescent probes

Multicellular spheroids are useful models of mammalian tissue for studies of cell proliferation, differentiation, replacement therapies and drug action. Having a size of 100–500 μm they mimic in vivo micro-environment and characteristic gradients of O₂, pH and nutrients. We describe the use of cell-penetrating O₂ probes based on phosphorescent Pt-porphyrins to perform high-resolution 2D and 3D mapping of O₂ in spheroid structures by live cell fluorescence imaging technique. Optimised procedures for preparation of neurospheres from cortical neural cells isolated from embryonic rat brain, their staining with the phosphorescent O₂ probes NanO2 and MM2 and subsequent analysis of oxygenation on different live cell imaging platforms, including widefield and confocal phosphorescence lifetime imaging microscopy (PLIM), conventional confocal and two-photon ratiometric intensity based O₂ detection are presented. This is followed by a series of physiological experiments in which oxygenation patterns of the neurospheres are correlated with culturing conditions (atmospheric hypoxia and hyperoxia, size, growth factors), distribution of stem cells, mature neurons and astrocytes, HIF-2α stabilisation and responses to metabolic stimulation. The O₂ imaging method allows multiplexing with many conventional fluorescent probes to perform multi-parametric imaging analysis of cells in 3D microenvironment. It can be applied to other types of spheroids and 3D tissue models.     

A dual sensor for real-time monitoring of glucose and oxygen

A dual glucose and oxygen sensor in a polymer format was developed. The dual sensor composed of a blue emitter as the glucose probe, a red emitter as an oxygen probe, and a yellow emitter as a built-in reference probe which does not respond to either glucose or oxygen. All the three probes were chemically immobilized in a polyacrylamide-based matrix. Therefore, the dual sensor possesses three well separated emission colors and ratiometric approach is applicable for analysis of the glucose and oxygen concentration at biological conditions. The sensor was applied for real-time monitoring of glucose and oxygen consumption of bacterial cells, Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis), and mammalian cells of mouse macrophage J774 and human cervical cancer HeLa cell lines. On the other hand, in order to achieve satisfactory sensing performance for glucose, compositions of the matrices among poly(2-hydroxyethyl methacrylate), polyacrylamide, and poly(6-aminohexyl methacrylamide) which is a linker polymer for grafting the glucose probe, were optimized.     

Lack of evidence for an association between seminoma and human papillomavirus infection using GP5+/GP6+ consensus primers

Testicular germ cell tumors account for about 1% of all cancers. The incidence of these tumors is increasing and they represent the most common solid malignancies of young men aged 15–40 years with seminoma being one of the most common histotype. Pathogenesis of testicular germ cell tumors remains unknown and, although cryptorchidism is considered the main risk factor, there is evidence of an association with environmental and genetic risk factors. Human papillomaviruses (HPV) are a family of DNA viruses and represent a major risk factor for cervical cancer. In addition, they have been associated with other human non‐malignant and malignant diseases, including breast and head and neck cancer. HPV sequences have been detected throughout the male lower genitourinary tract as well as in seminal fluid and an increased testicular tumorigenesis has been reported in HPV transgenic mice. Aim of this study was to evaluate the potential involvement of HPV in human testicular tumorigenesis. Real‐time PCR employing GP5+/GP6+ consensus HPV primers was used to examine the presence of HPV sequences in a subset of human seminoma (n = 61) and normal testicles (n = 23). None of the specimens tested displayed the presence of HPV DNA. These findings do not support an association between HPV and human seminoma and warrant further studies to assess definitively the role of these viruses in human testicular tumorigenesis. J. Med. Virol. 85:105–109, 2012. © 2012 Wiley Periodicals, Inc.