Optogenetic approaches addressing extracellular modulation of neural excitability

The extracellular ionic environment in neural tissue has the capacity to influence, and be influenced by, natural bouts of neural activity. We employed optogenetic approaches to control and investigate these interactions within and between cells, and across spatial scales. We began by developing a temporally precise means to study microdomain-scale interactions between extracellular protons and acid-sensing ion channels (ASICs). By coupling single-component proton-transporting optogenetic tools to ASICs to create two-component optogenetic constructs (TCOs), we found that acidification of the local extracellular membrane surface by a light-activated proton pump recruited a slow inward ASIC current, which required molecular proximity of the two components on the membrane. To elicit more global effects of activity modulation on ‘bystander’ neurons not under direct control, we used densely-expressed depolarizing (ChR2) or hyperpolarizing (eArch3.0, eNpHR3.0) tools to create a slow non-synaptic membrane current in bystander neurons, which matched the current direction seen in the directly modulated neurons. Extracellular protons played contributory role but were insufficient to explain the entire bystander effect, suggesting the recruitment of other mechanisms. Together, these findings present a new approach to the engineering of multicomponent optogenetic tools to manipulate ionic microdomains, and probe the complex neuronal-extracellular space interactions that regulate neural excitability.

Analysis of lymphatic and blood vessel invasion biomarkers in T1 esophagogastric adenocarcinomas for improved patient prognostication

Lymphovascular invasion (LVI) in T1 esophagogastric adenocarcinoma may predict risk of recurrence despite definitive treatment with surgery or endoscopic resection. Podoplanin and CD34 are emerging biomarkers of lymphatic and blood vessel invasion, respectively, and could be adopted to refine LVI assessment. A consecutive series of 65 patients with T1 adenocarcinomas diagnosed at Nottingham University Hospitals were investigated. T1 tumors from 43/65 patients who received primary surgery only were suitable for LVI evaluation by hematoxylin and eosin (H&E) staining as well as by CD34 and Podoplanin immunohistochemistry. LVI was correlated to clinicopathological features and recurrence free survival. H&E staining detected LVI in 11.6% (5/43) of T1 tumors. CD34 and Podoplanin immunohistochemistry significantly improved LVI detection to 25.6% (11/43). Compared with LVI by H&E, immunohistochemical evaluation of blood vessel invasion (CD34) or lymphatic vessel invasion (Podoplanin) was significantly associated with higher grade (P = 0.005), submucosal invasion (T1b) (P = 0.018), lymph node positivity (N1) (P = 0.029) and poor recurrence free survival (P = 0.0003). Our study provides evidence that CD34 and Podoplanin immunohistochemistry could improve LVI detection and allow better prognostication of patients and optimum selection of definitive treatment. Larger multicenter studies are required for further validation that could have significant clinical implications.

Efficacy and tolerability of albiglutide versus placebo or pioglitazone over 1 year in people with type 2 diabetes currently taking metformin and glimepiride: HARMONY 5

AIMS

To investigate the efficacy and tolerability of albiglutide, a weekly glucagon-like peptide-1 receptor agonist, when added to metformin and glimepiride in a triple therapy regimen in people with type 2 diabetes mellitus.

METHODS

This was a 156-week, randomized, double-blind, parallel-group, multicentre study. In the present paper we describe the primary results, namely those at 52 weeks. Adult participants (n = 685) were randomly assigned to albiglutide (30 mg/week), pioglitazone (30 mg/day) or placebo. If needed, blinded uptitration of albiglutide (to 50 mg/week) and pioglitazone (to 45 mg/day) was allowed. The participant's current dose of metformin (>1500 mg/day) was maintained throughout. The glimepiride dose (4 mg/day), standardized before randomization, could be decreased if persistent hypoglycaemia occurred.

RESULTS

The week 52 model-adjusted difference in change of glycated haemoglobin (primary endpoint) for albiglutide versus placebo was -0.87 [95% confidence interval (CI) -1.07, -0.68]%-units (p < 0.001), and for albiglutide versus pioglitazone it was 0.25 (95% CI 0.10, 0.40)%-units; therefore, not non-inferior. In the albiglutide group only, fasting plasma glucose reduced rapidly in the first 2 weeks. Confirmed hypoglycaemia occurred in 14% of participants on albiglutide, 25% on pioglitazone and 14% on placebo. The mean (± standard error) weight change was -0.42 (±0.2) kg with albiglutide, +4.4 (±0.2) kg (p < 0.001) with pioglitazone, and -0.40 (±0.4) kg with placebo and serious adverse events occurred in 6.3, 9.0 and 6.1% of participants in the respective groups. Injection site reactions occurred in 13% of participants on albiglutide and resulted in treatment discontinuation for four participants (1.4%).

CONCLUSIONS

Albiglutide, as part of triple therapy, provided effective glucose-lowering and was generally well tolerated.

The utility of atlas-assisted segmentation in the male pelvis is dependent on the interobserver agreement of the structures segmented

OBJECTIVE

To investigate the relationship between the ability of atlas-based autosegmentation to reduce outlining time in the male pelvis (body, bladder, rectum, femoral heads, prostate and seminal vesicles) and the interobserver agreement in the delineation of these structures. To examine any increase of the interobserver agreement with the use of an autosegmentation tool.

METHODS

We created atlases in the ABAS™ system v. 2.0 (Elekta, Crawley, UK) and recorded the time to delineate the above structures on eight patients with and without its aid. We also measured the interobserver agreement in the structure definitions using several metrics [Dice's similarity coefficient (DSC), mean distance to conformity, percentage volume difference] with and without the aid of ABAS.

RESULTS

There is a high degree of correlation between the time saving with the use of ABAS and the degree of interobserver agreement (r = 0.90 for DSC). This indicates that for structures where the interobserver agreement is low (DSC < 0.65), the ABAS does not reduce outlining time. We found that the interobserver agreement is increased with ABAS only for the prostate.

CONCLUSION

Outlining time saved in the male pelvis is highly correlated with the interobserver agreement of the structures. Only for the prostate does the use of ABAS significantly reduce the amount of interobserver variation in contouring.

ADVANCES IN KNOWLEDGE

The use of autosegmentation software increases the outlining time for structures where the interobserver agreement is low. Any increase in the interobserver agreement in contouring with the aid of such software may be limited to those structures where there is currently mid-range agreement between observers.

Targeting cells with single vectors using multiple-feature Boolean logic

Precisely defining the roles of specific cell types is an intriguing frontier in the study of intact biological systems and has stimulated the rapid development of genetically encoded tools for observation and control. However, targeting these tools with adequate specificity remains challenging: most cell types are best defined by the intersection of two or more features such as active promoter elements, location and connectivity. Here we have combined engineered introns with specific recombinases to achieve expression of genetically encoded tools that is conditional upon multiple cell-type features, using Boolean logical operations all governed by a single versatile vector. We used this approach to target intersectionally specified populations of inhibitory interneurons in mammalian hippocampus and neurons of the ventral tegmental area defined by both genetic and wiring properties. This flexible and modular approach may expand the application of genetically encoded interventional and observational tools for intact-systems biology.

MRI-based abnormalities in young adults at risk of adverse bone health due to childhood-onset metabolic & endocrine conditions

OBJECTIVE

Traditional methods of bone densitometry may not provide a comprehensive assessment of bone health. We aimed to assess bone micro-architecture and bone marrow adiposity (BMA) by MRI in adults with osteogenesis imperfecta (OI) and endocrinopathy including GH deficiency and/or hypogonadism.

MEASUREMENTS

High-resolution micro-MRI images were acquired at the tibia using 3T MRI to calculate parameters of bone micro-architecture in seven adults with OI and 10 adults with endocrinopathies. MR Spectroscopy was performed in participants to calculate vertebral BMA, which was expressed as percentage fat fraction (%FF). Lumbar spine DXA was performed to assess bone mineral density. The MRI data were compared with a group of 22 healthy adults who were divided into two age-matched control groups.

RESULTS

Intra-operator repeatability was high, with an average CoV of 1% for micro-MRI and 2·5% for MRS. The ratio of apparent bone volume to total volume (appBV/TV) in the endocrinopathy and OI groups was lower than in age-matched control groups (P = 0·003 and P = 0·008 respectively). A weak association between DXA BMD and appBV/TV was also observed (r = 0·5, P = 0·045). %FF was higher in the endocrinopathy group than in the age-matched control group (P = 0·005), but no difference in %FF was observed between the OI group and their age-matched control group (P = 0·26).

CONCLUSIONS

MRI provides valuable detailed information on the micro-architecture and adiposity of bones and is capable of showing clear differences in bone parameters in a range of clinical conditions associated with abnormal bone health.

Experimental validation of a novel compact focusing scheme for future energy-frontier linear lepton colliders

A novel scheme for the focusing of high-energy leptons in future linear colliders was proposed in 2001 [P. Raimondi and A. Seryi, Phys. Rev. Lett. 86, 3779 (2001)]. This scheme has many advantageous properties over previously studied focusing schemes, including being significantly shorter for a given energy and having a significantly better energy bandwidth. Experimental results from the ATF2 accelerator at KEK are presented that validate the operating principle of such a scheme by demonstrating the demagnification of a 1.3 GeV electron beam down to below 65 nm in height using an energy-scaled version of the compact focusing optics designed for the ILC collider.

Bcl2 is an independent prognostic marker of triple negative breast cancer (TNBC) and predicts response to anthracycline combination (ATC) chemotherapy (CT) in adjuvant and neoadjuvant settings

BACKGROUND

TNBC represents a heterogeneous subgroup of BC with poor prognosis and frequently resistant to CT.

MATERIAL AND METHODS

The relationship between Bcl2 immunohistochemical protein expression and clinico-pathological outcomes was assessed in 736 TNBC-patients: 635 patients had early primary-TNBC (EP-TNBC) and 101 had primary locally advanced (PLA)-TNBC treated with neo-adjuvant- ATC-CT.

RESULTS

Negative Bcl2 (Bcl2-) was observed in 70% of EP-TNBC and was significantly associated with high proliferation, high levels of P-Cadherin, E-Cadherin and HER3 (P's < 0.01), while Bcl2+ was significantly associated with high levels of p27, MDM4 and SPAG5 (P < 0.01). After controlling for chemotherapy and other prognostic factors, Bcl2- was associated with 2-fold increased risk of death (P = 0.006) and recurrence (P = 0.0004). Furthermore, the prognosis of EP-TNBC/Bcl2- patients had improved both BC-specific survival (P = 0.002) and disease-free survival (P = 0.003), if they received adjuvant-ATC-CT. Moreover, Bcl2- expression was an independent predictor of pathological complete response of primary locally advanced triple negative breast cancer (PLA-TNBC) treated with neoadjuvant-ATC-CT (P = 0.008).

CONCLUSION

Adding Bcl2 to the panel of markers used in current clinical practice could provide both prognostic and predictive information in TNBC. TNBC/Bcl2- patients appear to benefit from ATC-CT, whereas Bcl2+ TNBC seems to be resistant to ATC-CT and may benefit from a trial of different type of chemotherapy with/without novel-targeted agents.

VimA-dependent modulation of the secretome in Porphyromonas gingivalis

The VimA protein of Porphyromonas gingivalis is a multifunctional protein involved in cell surface biogenesis. To further determine if its acetyl coenzyme A (acetyl-CoA) transfer and putative sorting functions can affect the secretome, its role in peptidoglycan biogenesis and effects on the extracellular proteins of P. gingivalis FLL92, a vimA-defective mutant, were evaluated. There were structural and compositional differences in the peptidoglycan of P. gingivalis FLL92 compared with the wild-type strain. Sixty-eight proteins were present only in the extracellular fraction of FLL92. Fifteen proteins present in the extracellular fraction of the parent strain were missing in the vimA-defective mutant. These proteins had protein sorting characteristics that included a C-terminal motif with a common consensus Gly-Gly-CTERM pattern and a polar tail consisting of aromatic amino acid residues. These observations suggest that the VimA protein is likely involved in peptidoglycan synthesis, and corroborates our previous report, which suggests a role in protein sorting.

Klebsiella pneumoniae producing KPC carbapenemase in a district general hospital in the UK

We report two patients with multidrug-resistant KPC-carbapenemase-producing Klebsiella pneumoniae urinary tract infections. A bla(KPC-2) gene was detected in both of the isolates by polymerase chain reaction and sequencing. The isolates had identical pulsed-field gel electrophoresis patterns and belonged to sequence type ST11. The index patient probably acquired the KPC-producing strain while in hospital in Curaçao, with subsequent nosocomial transmission to the second patient occurring in our hospital. We describe the interventions that were taken to prevent its further spread within the acute Trust and the community.

Geostatistical modeling of the spatial variability and risk areas of southern root-knot nematodes in relation to soil properties

Identifying the spatial variability and risk areas for southern root-knot nematode [Meloidogyne incognita (Kofoid & White) Chitwood] (RKN) is key for site-specific management (SSM) of cotton (Gossypium hirsutum L.) fields. The objectives of this study were to: (i) determine the soil properties that influence RKN occurrence at different scales; and (ii) delineate risk areas of RKN by indicator kriging. The study site was a cotton field located in the southeastern coastal plain region of the USA. Nested semivariograms indicated that RKN samples, collected from a 50×50 m grid, exhibited a local and regional scale of variation describing small and large clusters of RKN population density. Factorial kriging decomposed RKN and soil properties variability into different spatial components. Scale dependent correlations between RKN data showed that the areas with high RKN population remained stable though the growing season. RKN data were strongly correlated with slope (SL) at local scale and with apparent soil electrical conductivity deep (EC(a-d)) at both local and regional scales, which illustrate the potential of these soil physical properties as surrogate data for RKN population. The correlation between RKN data and soil chemical properties was soil texture mediated. Indicator kriging (IK) maps developed using either RKN, the relation between RKN and soil electrical conductivity or a combination of both, depicted the probability for RKN population to exceed the threshold of 100 second stage juveniles/100 cm(3) of soil. Incorporating EC(a-d) as soft data improved predictions favoring the reduction of the number of RKN observations required to map areas at risk for high RKN population.