Chris MacDonald

Activating positive memory engrams suppresses depression-like behaviour

Stress is considered a potent environmental risk factor for many behavioural abnormalities, including anxiety and mood disorders. Animal models can exhibit limited but quantifiable behavioural impairments resulting from chronic stress, including deficits in motivation, abnormal responses to behavioural challenges, and anhedonia. The hippocampus is thought to negatively regulate the stress response and to mediate various cognitive and mnemonic aspects of stress-induced impairments, although the neuronal underpinnings sufficient to support behavioural improvements are largely unknown. Here we acutely rescue stress-induced depression-related behaviours in mice by optogenetically reactivating dentate gyrus cells that were previously active during a positive experience. A brain-wide histological investigation, coupled with pharmacological and projection-specific optogenetic blockade experiments, identified glutamatergic activity in the hippocampus–amygdala–nucleus-accumbens pathway as a candidate circuit supporting the acute rescue. Finally, chronically reactivating hippocampal cells associated with a positive memory resulted in the rescue of stress-induced behavioural impairments and neurogenesis at time points beyond the light stimulation. Together, our data suggest that activating positive memories artificially is sufficient to suppress depression-like behaviours and point to dentate gyrus engram cells as potential therapeutic nodes for intervening with maladaptive behavioural states.

Charitable Conflicts of Interest

This paper looks at conflicts of interest in the not-for-profit sector. It examines the nature of conflicts of interest and why they are of ethical concern, and then focuses on the way not-for-profit organisations are especially prone to and vulnerable to conflict-of-interest scandals. Conflicts of interest corrode trust; and stakeholder trust (particularly from donors) is the lifeblood of most charities. We focus on some specific challenges faced by charitable organisations providing funding for scientific (usually medical) research, and examine a case study involving such an organisation. One of the principal problems for charities of this kind is that they often distribute their funds within a relatively small research community (defined by the boundaries of a small region, like an American state or Spanish Autonomous region, or a small country), and it often proves difficult to find high-level researchers within the jurisdiction to adjudicate impartially the research grants. We suggest and recommend options appropriate for our case study and for many other organisations in similar situations.

Ethics and Genetics: Susceptibility Testing in the Workplace

Genetic testing in the workplace is a technology both full of promise and fraught with ethical peril. Though not yet common, it is likely to become increasingly so. We survey the key arguments in favour of such testing, along with the most significant ethical worries. We further propose a set of pragmatic criteria, which, if met, would make it permissible for employers to offer (but not to require) workplace genetic testing.

Proton-Coupled Oligopeptide Transporter (POT) Family Expression in Human Nasal Epithelium and Their Drug Transport Potential

The molecular and functional expression of peptide transporters (PEPT1 and PEPT2, PHT1, PHT2) in human nasal epithelium was investigated. Quantitative/reverse transcriptase polymerase chain reaction (qPCR/RT-PCR), Western blotting and indirect immuno-histochemistry were used to investigate the functional gene and protein expression for the transporters. Uptake and transport studies were performed using metabolically stable peptides [β-alanyl-L-lysyl-Nε-7-amino-4-methyl-coumarin-3-acetic acid (β-Ala-Lys-AMCA) and β-alanyl-L-histidine (carnosine)]. The effects of concentration, temperature, polarity, competing peptides, and inhibitors on peptide uptake and transport were investigated. PCR products corresponding to PEPT1 (150 bp), PEPT2 (127 bp), PHT1 (110 bp) and PHT2 (198 bp) were detected. Immunohistochemistry and Western blotting confirmed the functional expression of PEPT1 and PEPT2 genes. The uptake of β-Ala-Lys-AMCA was concentration-dependent and saturable (Vmax =4.1 ( 0.07 μmol/min/mg protein, Km = 0.6 ( 0.07 μM). The optimal pH for intracellular accumulation of β-Ala-Lys-AMCA was 6.5. Whereas dipeptides and carbonyl cyanide m-chlorophenylhydrazone (CCCP) significantly inhibited peptide uptake and transport, L-Phe had no effect on peptide transport. The permeation of β-alanyl-L-histidine was concentration-, direction-, and temperature-dependent. The uptake, permeation, qPCR/RT-PCR and protein expression data showed that the human nasal epithelium functionally expresses proton-coupled oligopeptide transporters.

Relational Professional Autonomy

The notion of “relational” autonomy—as described by feminist scholars such as Susan Sherwin and Anne Donchin—has been the subject of a significant body of literature over the last few years and has recently generated some interest within the field of bioethics. Although the focus of this interest has been the autonomy of ordinary moral agents, the analysis of relational autonomy can usefully be extended to apply to the autonomy of professionals, not only as individual moral agents, but in their roles as professionals as well. In this paper, I argue that professional autonomy, rightly understood, is relational in nature. This understanding of professional autonomy stands to improve our understanding of professional ethics, as well as providing a particular, concrete example of what we mean when we call autonomy “relational” and “socially embedded.

Characterization of Calu-3 cell monolayers as a model of bronchial epithelial transport: organic cation interaction studies

Background: To fully exploit organic cation transporters for targeted drug delivery in the lung, the use of a readily available and well-characterized tissue culture model and cheap easily detectable substrates is indispensable. Objectives: To investigate the suitability of Calu-3 as tissue model for characterizing organic cation permeation across the bronchial cells using a fluorescent dye, 4-(4-(Dimethylamino)styryl)-N-methylpyridinium iodide (4-DI-1-ASP). Methods: Substrate uptake, inhibition, and transport were performed to establish active transport mechanism. Organic cation transporter expression was determined with quantitative polymerase chain reaction (qPCR), immune-histochemistry, and fluorescent microscopy. Results: 4-Di-1-ASP uptake in Calu-3 cells was concentration (Km = 2.7 ± 0.3 mM, Vmax = 4.6 ± 2.6 nmol/µg protein/30 min), temperature (uptake at 37°C>>4°C), and pH dependent (higher uptake at pH ≥ 7). L-carnitine, verapamil, and corticosterone significantly inhibited its uptake with IC50 of 28.2, 0.81, and 0.12 mM, respectively. Transport of the dye across the cells was polarized (AP→BL transport was 2.5-fold > BL→AP), saturable (Km = 43.9 ± 3.2) (µM; Vmax =0.0228± nmol/cm2/sec) and reduced 3-fold by metabolic inhibition. The expression pattern of the organic cation transporters (OCT) and carnitine/organic cation transporter (OCTN) isoforms was: OCT1<<OCT3 <OCTN1<OCTN2; OCT2 was not detected. Conclusions: Based on qPCR, immunohistochemistry, uptake and transport data, the Calu-3 cells can be used as a model for not only studying strategies for optimizing the effect of inhaled organic cations, but also for cross-validating newly-developed respiratory cell lines.

Differential expression of organic cation transporters in normal and polyps human nasal epithelium: Implications for in vitro drug delivery studies

The aim of this study was to compare the expression of organic cation transporters (OCTs) in normal and polyps nasal epithelium. Primary cell cultures of human nasal epithelium (polyps and normal tissues) were compared by investigating the uptake of a fluorescent organic cation, [4-dimethylaminostyryl-N-methylpyridinium (4-Di-1-ASP)]. The effect of concentration, temperature, pH and competing inhibitors were investigated. Quantitative polymerase chain reaction (qPCR) was used to compare the OCTs gene expression levels in the cells. The K(m) (μM) and V(max) (μM/mg protein/15 min) for 4-Di-1-ASP uptake were higher in normal (K(m)=3031 ± 559.6, V(max)=70.8 ± 8.8) cells compared to polyps (K(m)=952.4 ± 207.8, V(max)=30.9 ± 2.1). qPCR results showed that OCT1-3 and organic cation/carnitine transporter 1-2 gene transcripts (OCTN1-2) were expressed in both normal and polyps cells at comparable levels, with OCT-3 having the highest expression level in both cultures. Kruskal-Wallis ANOVA showed that pH and specific inhibitors had similar effects on both normal and polyps cells (p>0.5). Similarly, OCTs and OCTNs gene expression levels were similar. This study showed that polyps biopsies can be used for isolating cells to study organic cation transporters in human nasal epithelium as no major functional or molecular differences relative to normal cells could be found.

Business Ethics 101 for the Biotech Industry

Biotechnology companies face ethical challenges of two distinct types: bioethical challenges faced on account of the nature of work in the life sciences, and corporate ethical challenges on account of their nature as commercial entities. The latter set of challenges has received almost no attention at all in the academic literature or media. This paper begins to remedy that lacuna, examining ethical issues that arise specifically on account of the status of biotech companies as commercial entities. The focus here is on three representative issues: product safety, corporate social responsibility, and corporate governance. It is argued that each of these issues poses particular ethical challenges for companies in the biotech sector. In the area of product safety, it is noted that biotech companies face particular challenges in determining what counts as a ‘safe’ product, given the contentious nature of what might count as a ‘harm’ in the biotech field. In the area of corporate social responsibility, the adoption of a ‘stakeholder approach’ and an attempt to manage the social consequences of products pose special challenges for biotech companies. This is due to the enormous range of groups and individuals claiming to have a stake in the doings of such companies, and the trenchant controversies over just what the social consequences of various biotechnologies might be. In the area of corporate governance, biotech companies need to seek out and follow best practices regarding the ways in which information, authority, and influence flow between a company’s shareholders, managers, and Board of Directors, if they are to avoid duplicating the ethical and financial scandal that brought down ImClone. An important meta-issue, here — one that renders each of these corporate ethical challenges more vexing — is the difficulty of finding the appropriate benchmarks for ethical corporate behavior in a field as controversial, and as rapidly evolving, as biotechnology. Three programmatic suggestions can be made: Firstly, scholars and others interested in the ethical performance of the biotech sector must seek out and build opportunities for richer interdisciplinary collaboration. Secondly, companies within the biotech sector must seek out expertise and build capacity and competency in dealing with the corporate ethical issues that arise in their sector. Finally, companies in the biotech sector should explore the opportunities for collective problem solving afforded by the existence of local, national, and international industry associations such as the Biotechnology Industry Organization, BIOTECanada, and EuropaBio.

Water-soluble organic solubilizers for in vitro drug delivery studies with respiratory epithelial cells: Selection based on various toxicity indicators

The aim of this study was to use different toxicity indices to investigate the effect of N, N-Dimethylacetamide (DMA), Polyethylene glycol 400 (PEG 400), Methyl-Pyrrolidone/aromatic hydrocarbon (MPH), Cremophor® EL, and Dimethylsulfoxide (DMSO) on Calu-3 cells. Membrane perturbation and cytotoxicity were investigated using lactate dehydrogenase (LDH), 3-[4, 5-Dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolinium bromide (MTT), transepithelial electrical resistance (TEER) assessment, sodium fluorescein (SF) permeation, and phalloidin actin staining. The MDH activity of cells treated with DMSO (≤ 4.0 v/v), Cremophor EL (≤ 10% v/v), and PEG 400 (≤ 10% v/v) was not significantly altered (p > 0.5). Similarly, DMSO (≤ 8.0% v/v), Cremophor® EL (≤ 16.0% v/v) and PEG 400 (≤ 32.0% v/v) had no significant effect on LDH (p > 0.05). Conversely, MPH and DMA at very low concentrations (≤ 0.25% v/v) induced cell toxicity. However, up to 2.0% v/v MPH and (DMA) had no effect on TEER and SF permeation. No obvious change in actin staining was observed for DMSO (15%), Cremophor® EL (15%), and MPA (1%). However, the actin architecture for cells treated with DMA (1%) and PEG 400 (15%) appeared significantly different from control. Based on this study Cremophor (≤ 10%), PEG 400 (≤ 5%), and DMSO (≤ 5%), and low concentrations of DMA and MPA (≤ 0.25%) were suitable for in vitro studies with Calu-3 cells.

Personal Genomics: Democratization, or Empowerment, or ‘Something’

about their phenotypic characteristics, such as age, gender, and disease status (Linz et al. 2004). If an individual can be identified in a database, it may also be possible to identify some of the individual’s close relatives as well, due to shared genomic characteristics (Linz et al. 2004). One implication of these and other studies is that removal of personal identifiers is no longer a surefire method for protecting confidentiality when sharing genomic information (Zerhouni and Nabel 2008). In response to the limitations of using de-identification as a method for protecting the confidentiality of genomic data, several biomedical research organizations, including the National Institutes of Health (NIH), have moved away from open access data-sharing policies (Zerhouni and Nabel 2008). The NIH has decided that data from genome-wide association studies will be released only to researchers and institutions who sign an agreement stating terms and conditions pertaining to how the data will be used, protected, stored, and shared (Zerhouni and Nabel 2008). Individuals who share the genomic and health information on social networks may not fully comprehend the potential consequences of data sharing. They may not understand that by sharing information on social networks they risk their own confidentiality as well as the confidentiality of their family members. Private companies that offer these services should take appropriate steps to inform individuals about confidentiality risks and take steps to protect individuals and their families from harm.