Targeted Molecular Imaging Using Aptamers in Cancer

Imaging is not only seeing, but also believing. For targeted imaging modalities, nucleic acid aptamers have features such as superior recognition of structural epitopes and quick uptake in target cells. This explains the emergence of an evolved new class of aptamers into a wide spectrum of imaging applications over the last decade. Genetically encoded biosensors tagged with fluorescent RNA aptamers have been developed as intracellular imaging tools to understand cellular signaling and physiology in live cells. Cancer-specific aptamers labeled with fluorescence have been used for assessment of clinical tissue specimens. Aptamers conjugated with gold nanoparticles have been employed to develop innovative mass spectrometry tissue imaging. Also, use of chemically conjugated cancer-specific aptamers as probes for non-invasive and high-resolution imaging has been transformative for in vivo imaging in multiple cancers.

Structural stability of interaction networks against negative external fields

We explore structural stability of weighted and unweighted networks of positively interacting agents against a negative external field. We study how the agents support the activity of each other to confront the negative field, which suppresses the activity of agents and can lead to collapse of the whole network. The competition between the interactions and the field shape the structure of stable states of the system. In unweighted networks (uniform interactions) the stable states have the structure of k-cores of the interaction network. The interplay between the topology and the distribution of weights (heterogeneous interactions) impacts strongly the structural stability against a negative field, especially in the case of fat-tailed distributions of weights. We show that apart from critical slowing down there is also a critical change in the system structure that precedes the network collapse. The change can serve as an early warning of the critical transition. To characterize changes of network structure we develop a method based on statistical analysis of the k-core organization and so-called "corona" clusters belonging to the k-cores.

Astrocytic water channel aquaporin-4 modulates brain plasticity in both mice and humans: a potential gliogenetic mechanism underlying language-associated learning

The role of astrocytes in brain plasticity has not been extensively studied compared with that of neurons. Here we adopted integrative translational and reverse-translational approaches to explore the role of an astrocyte-specific major water channel in the brain, aquaporin-4 (AQP4), in brain plasticity and learning. We initially identified the most prevalent genetic variant of AQP4 (single nucleotide polymorphism of rs162008 with C or T variation, which has a minor allele frequency of 0.21) from a human database (n=60 706) and examined its functionality in modulating the expression level of AQP4 in an in vitro luciferase reporter assay. In the following experiments, AQP4 knock-down in mice not only impaired hippocampal volumetric plasticity after exposure to enriched environment but also caused loss of long-term potentiation after theta-burst stimulation. In humans, there was a cross-sectional association of rs162008 with gray matter (GM) volume variation in cortices, including the vicinity of the Perisylvian heteromodal language area (Sample 1, n=650). GM volume variation in these brain regions was positively associated with the semantic verbal fluency. In a prospective follow-up study (Sample 2, n=45), the effects of an intensive 5-week foreign language (English) learning experience on regional GM volume increase were modulated by this AQP4 variant, which was also associated with verbal learning capacity change. We then delineated in mice mechanisms that included AQP4-dependent transient astrocytic volume changes and astrocytic structural elaboration. We believe our study provides the first integrative evidence for a gliogenetic basis that involves AQP4, underlying language-associated brain plasticity.

Community health needs assessment: a nurses' global health project in Vietnam

BACKGROUND

Global health has been directed to providing solutions to various health issues cross-nations, and nurses have received wide recognition as a key health workforce to reduce health disparities globally. Nurses involved in global health research are required to implement evidence-based global nursing practices based on the assessments of local health needs.

AIM

To assess health needs and to suggest future interventions in rural communities of Vietnam.

METHODS

A multifaceted rapid participatory appraisal with information pyramid was used applying mixed methods from six sources: existing record review, surveys of community residents, surveys of healthcare providers, focus group discussions with community leaders, informal discussions with governmental health administrators and observations of community health station (CHS) facilities.

RESULTS

The majority used the CHSs as primary health facilities with high satisfaction for services currently provided. However, there were needs for the stations to provide more comprehensive services including chronic diseases, and for healthcare providers to improve their competences. Community leaders showed high interest in health information for chronic diseases and strong commitment to involvement in the activities for health of their communities. The findings suggest future interventions in the areas of the enhancement of CHS' functions, human resources and the self-care capacity of community residents.

CONCLUSION AND POLICY IMPLICATIONS

The rapid participatory appraisal approach emphasizing community participation and partnership was a useful tool to compile accurate information about the current needs of the community on health, the preparedness of healthcare services to meet community's demands and about community capacity. This process is fundamental to nurses, who initiate global health projects in resource-limited international countries, to generate evidences regarding practice, research and policy for taking responsibilities in promoting the sustainable development goals.

Randomised trial comparing forced-air warming to the upper or lower body to prevent hypothermia during thoracoscopic surgery in the lateral decubitus position

BACKGROUND

In the supine position, forced-air warming is more effective on the lower body than on the upper body to prevent intraoperative hypothermia. However, it is unknown in the lateral decubitus position. We thus compared forced-air warming on the upper and lower bodies in the lateral position.

METHODS

Patients (n=123) were randomised to receive forced-air warming on the upper body or lower body during thoracoscopic surgery in the lateral position. We measured the nasopharyngeal temperature at 0, 30, 60, 90, and 120 min after lateral positioning during surgery and the infrared tympanic membrane temperature at 0, 30, 60, 90, and 120 min after surgery. Patients received both upper and lower body warming at a temperature of <35.5°C. The primary outcome was the incidence of intraoperative hypothermia with a temperature of <36.0°C.

RESULTS

Intraoperative hypothermia was less frequent with the upper body warming than with the lower body warming {21/62 vs 35/61, risk ratio [95% confidence interval (CI)] 0.6 (0.4-0.9), P=0.011}. The intraoperative temperature was higher with the upper body warming than with the lower body warming at 30 (P=0.002), 60 (P<0.001), and 90 (P<0.001) min after lateral positioning, and the postoperative temperature was higher at 0 (P<0.001) and 30 (P=0.001) min after surgery. Fewer patients received both upper and lower body warming in the upper body warming group than in the lower body warming group during surgery (1 vs 7, P=0.032).

CONCLUSIONS

Forced-air warming was more effective on the upper body than on the lower body to prevent hypothermia during thoracoscopic surgery in the lateral decubitus position.

CLINICAL TRIAL REGISTRATION

NCT02993666.

Underage drinking, group identity and access to alcohol: a qualitative study of Chinese youths

Despite substantial research into underage youth's source of alcohol, few studies have examined how they go about obtaining alcohol through various means. This study explored the nature of alcohol access by Chinese adolescents and how their own perceptions around alcohol availability influence them to source alcohol in particular ways. This research involved focus groups with 111 young people aged 14-17 in Hong Kong, China. A grounded theory analysis was conducted using NVivo 10. While participants perceived ease of obtaining alcohol from retail outlets, proxy purchasing through friendship group members was reported as routine experience primarily to avoid potential embarrassment of being turned away. Convincing vendors that they were of legal drinking age was the convention used most commonly by Chinese teen drinkers. Participants expressed resentment toward adults who were willing to supply minors with alcohol. Nevertheless, this feeling of disappointment did not alter the ways they sourced alcohol. Access activities embodied a symbol of group identity in the collectivist Chinese culture. Results suggest that greater consideration should be given to understanding the complex interplay between alcohol access and community experience within peers. The perceived importance of face saving in Chinese culture may provide avenues for preventing youth access to alcohol.

Blind SELEX Approach Identifies RNA Aptamers That Regulate EMT and Inhibit Metastasis

Identifying targets that are exposed on the plasma membrane of tumor cells, but expressed internally in normal cells, is a fundamental issue for improving the specificity and efficacy of anticancer therpeutics. Using blind cell Systemic Evolution of Ligands by EXponetial enrichment (SELEX), which is untargeted SELEX, we have identified an aptamer, P15, which specifically bound to the human pancreatic adenocarcinoma cells. To identify the aptamer binding plasma membrane protein, liquid chromatography tandem mass spectrometry (LC-MS/MS) was used. The results of this unbiased proteomic mass spectrometry approach identified the target of P15 as the intermediate filament vimentin, biomarker of epithelial-mesenchymal transition (EMT), which is an intracellular protein but is specifically expressed on the plasma membrane of cancer cells. As EMT plays a pivotal role to transit cancer cells to invasive cells, tumor cell metastasis assays were performed in vitro P15-treated pancreatic cancer cells showed the significant inhibition of tumor metastasis. To investigate the downstream effects of P15, EMT-related gene expression analysis was performed to identify differently expressed genes (DEG). Among five DEGs, P15-treated cells showed the downregulated expression of matrix metallopeptidase 3 (MMP3), which is involved in cancer invasion. These results, for the first time, demonstrate that P15 binding to cell surface vimentin inhibits the tumor cell invasion and is associated with reduced MMP3 expression. Thus, suggesting that P15 has potential as an anti-metastatic therapy in pancreatic cancer.Implications: This study reveals that anti-vimentin RNA aptamers selected via blind-SELEX inhibit the tumor cell metastasis. Mol Cancer Res; 15(7); 811-20. ©2017 AACR.

Aptamer-Drug Conjugates of Active Metabolites of Nucleoside Analogs and Cytotoxic Agents Inhibit Pancreatic Tumor Cell Growth

Aptamer-drug conjugates (ApDCs) have the potential to improve the therapeutic index of traditional chemotherapeutic agents due to their ability to deliver cytotoxic drugs specifically to cancer cells while sparing normal cells. This study reports on the conjugation of cytotoxic drugs to an aptamer previously described by our group, the pancreatic cancer RNA aptamer P19. To this end, P19 was incorporated with gemcitabine and 5-fluorouracil (5-FU), or conjugated to monomethyl auristatin E (MMAE) and derivative of maytansine 1 (DM1). The ApDCs P19-dFdCMP and P19-5FdUMP were shown to induce the phosphorylation of histone H2AX on Ser139 (γ-H2AX) and significantly inhibited cell proliferation by 51%–53% in PANC-1 and by 54%–34% in the gemcitabine-resistant pancreatic cancer cell line AsPC-1 (p ≤ 0.0001). P19-MMAE and P19-DM1 caused mitotic G2/M phase arrest and inhibited cell proliferation by up to 56% in a dose-dependent manner when compared to the control group (p ≤ 0.001). In addition, the cytotoxicity of P19-MMAE and P19-DM1 in normal cells and the control human breast cancer cell line MCF7 was minimal. These results suggest that this approach may be useful in decreasing cytotoxic side effects in non-tumoral tissue.