A functional cellulose synthase from ascidian epidermis

Among animals, urochordates (e.g., ascidians) are unique in their ability to biosynthesize cellulose. In ascidians cellulose is synthesized in the epidermis and incorporated into a protective coat know as the tunic. A putative cellulose synthase-like gene was first identified in the genome sequences of the ascidian Ciona intestinalis. We describe here a cellulose synthase gene from the ascidian Ciona savignyi that is expressed in the epidermis. The predicted C. savignyi cellulose synthase amino acid sequence showed conserved features found in all cellulose synthases, including plants, but was most similar to cellulose synthases from bacteria, fungi, and Dictyostelium discoidium. However, unlike other known cellulose synthases, the predicted C. savignyi polypeptide has a degenerate cellulase-like region near the carboxyl-terminal end. An expression construct carrying the C. savignyi cDNA was found to restore cellulose biosynthesis to a cellulose synthase (CelA) minus mutant of Agrobacterium tumefaciens, showing that the predicted protein has cellulose synthase activity. The lack of cellulose biosynthesis in all other groups of metazoans and the similarity of the C. savignyi cellulose synthase to enzymes from cellulose-producing organisms support the hypothesis that the urochordates acquired the cellulose biosynthetic pathway by horizontal transfer.     

What has happened in the last 50 years in immunology

Fifty years ago, in 1964, our understanding of the immune system was very rudimentary. Gell and Coombs had just described classes of hypersensitivity reactions, and Bruton had described and commenced immunoglobulin replacement in agammaglobulinaemia. The distinction between T and B cells was not identified and characterised until the 1960s and 1970s. This was followed by increasing recognition of T and B cell collaboration in immune responses and identification of significant immunodeficiencies. CD4 and CD8 T cells were only recognised in the 1970s and 1980s. We now know of five CD4 subsets; dysfunction of each is associated with different disorders. By 2014, advances in technology have enabled identification of the genetic basis of over 240 primary immunodeficiencies. Research into the gut microbiome and vitamin D holds promise for the understanding, treatment and prevention of autoimmune and allergic diseases. Immunoglobulin preparations for the treatment of antibody deficiencies improved with the development of preparations for intravenous then subcutaneous administration, giving patients choice and the ability for home‐based treatment, especially if experiencing infusion associated adverse effects. Newborn screening for severe combined immunodeficiency is a reality. Improvements in haemopoietic stem cell transplantation and now gene therapy, albeit still only available in the research setting, are improving long‐term survival in primary immunodeficiencies. Biologic therapeutic agents are improving the control of autoimmune disease but potentially leading to secondary immunodeficiency, increasing the risk of opportunistic infection and malignancy. It is an exciting time.     

Regenerative peripheral nerve interfaces for real-time,proportional control of a Neuroprosthetic hand

Introduction

Regenerative peripheral nerve interfaces (RPNIs) are biological constructs which amplify neural signals and have shown long-term stability in rat models. Real-time control of a neuroprosthesis in rat models has not yet been demonstrated. The purpose of this study was to: a) design and validate a system for translating electromyography (EMG) signals from an RPNI in a rat model into real-time control of a neuroprosthetic hand, and; b) use the system to demonstrate RPNI proportional neuroprosthesis control.

Methods

Animals were randomly assigned to three experimental groups: (1) Control; (2) Denervated, and; (3) RPNI. In the RPNI group, the extensor digitorum longus (EDL) muscle was dissected free, denervated, transferred to the lateral thigh and neurotized with the residual end of the transected common peroneal nerve. Rats received tactile stimuli to the hind-limb via monofilaments, and electrodes were used to record EMG. Signals were filtered, rectified and integrated using a moving sample window. Processed EMG signals (iEMG) from RPNIs were validated against Control and Denervated group outputs.

Results

Voluntary reflexive rat movements produced signaling that activated the prosthesis in both the Control and RPNI groups, but produced no activation in the Denervated group. Signal-to-Noise ratio between hind-limb movement and resting iEMG was 3.55 for Controls and 3.81 for RPNIs. Both Control and RPNI groups exhibited a logarithmic iEMG increase with increased monofilament pressure, allowing graded prosthetic hand speed control (R²?=?0.758 and R²?=?0.802, respectively).

Conclusion

EMG signals were successfully acquired from RPNIs and translated into real-time neuroprosthetic control. Signal contamination from muscles adjacent to the RPNI was minimal. RPNI constructs provided reliable proportional prosthetic hand control.

     

Deformation strain is the main physical driver for skeletal precursors to undergo osteogenesis in earlier stages of osteogenic cell maturation

Mesenchymal stem cells play a major role during bone remodelling and are thus of high interest for tissue engineering and regenerative medicine applications. Mechanical stimuli, that is, deformation strain and interstitial fluid‐flow‐induced shear stress, promote osteogenic lineage commitment. However, the predominant physical stimulus that drives early osteogenic cell maturation is not clearly identified. The evaluation of each stimulus is challenging, as deformation and fluid‐flow‐induced shear stress interdepend. In this study, we developed a bioreactor that was used to culture mesenchymal stem cells harbouring a strain‐responsive AP‐1 luciferase reporter construct, on porous scaffolds. In addition to the reporter, mineralization and vitality of the cells was investigated by alizarin red staining and 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide. Quantification of the expression of genes associated to bone regeneration and bone remodelling was used to confirm alizarin red measurements. Controlled perfusion and deformation of the 3‐dimensional scaffold facilitated the alteration of the expression of osteogenic markers, luciferase activity, and calcification. To isolate the specific impact of scaffold deformation, a computational model was developed to derive a perfusion flow profile that results in dynamic shear stress conditions present in periodically loaded scaffolds. In comparison to actually deformed scaffolds, a lower expression of all measured readout parameters indicated that deformation strain is the predominant stimulus for skeletal precursors to undergo osteogenesis in earlier stages of osteogenic cell maturation.     

Sleep Mediates the Association Between PTSD Symptoms and Chronic Pain in Youth

Symptoms of post-traumatic stress disorder (PTSS) and chronic pain have been shown to co-occur at high rates in adolescents and this co-occurrence is linked to worse pain and quality of life. Sleep disturbance has been posited as a mechanism underlying this co-occurrence in conceptual models of mutual maintenance. This study examined the mediating role of sleep in the relationship between PTSS and pain in youth (aged 10–17 years) with chronic pain. Ninety-seven participants completed measures of PTSS, pain (intensity and interference), anxiety symptoms, and sleep quality, in addition to demographic characteristics. Mediation models were conducted. Findings revealed that, over and above the influence of associated demographic characteristics (age, race) and anxiety symptoms, sleep quality partially mediated the relationships between PTSS and pain intensity and interference for youth with chronic pain. Specifically, higher levels of PTSS was linked to higher levels of pain intensity and pain interference, and these relationships were partially explained by poor sleep quality. Findings highlight the potential mechanistic role of sleep in explaining the co-occurrence of chronic pain and PTSS and suggest sleep might be an important target in future interventions.

Attentional and Interpretational Biases Toward Pain-Related Stimuli in Children and Adolescents: ASystematic Review of the Evidence

This review investigated whether youth exhibit attention or interpretation biases toward pain-related information and whether such biases are more pronounced in youth with chronic pain. Three databases were searched to identify studies that assessed attention or interpretation biases using an accepted experimental paradigm. Ten studies were identified, 8 examining attentional biases and 2 examining interpretation biases. As in the adult literature, there was no evidence of attentional biases toward pain in youth without chronic pain. Three studies investigating youth without chronic pain found evidence for relationships between catastrophizing or anxiety and indicators of vigilance or avoidance (in 2 cases, for youth with low self-reported attentional control). For attentional biases, 5 studies compared youth with and without chronic pain. Two of these studies measured cortical correlates and found evidence of neurologic activity indicating a bias in orienting to pain-related stimuli. Three studies examined biases toward pain-related words or pictures. Of those, 2 found evidence of biases at subliminal presentation times, indicating vigilance (although 1 only after a stressful task). For supraliminal presentations, 1 study found evidence of avoidance, one of difficulty disengaging, and one of general slowing of responses. Only 1 study compared youth with and without pain for interpretation bias in adolescents, and interpretation biases were greater for youth with chronic pain. As with attention, no evidence for interpretation biases were found in youth without chronic pain. Overall, there is weak evidence to support vigilance in youth with chronic pain compared with those without. However, whether pain affects the subsequent deployment of attention is unclear. There is no evidence for biases toward pain in youth without chronic pain, but evidence suggests that anxiety or catastrophizing and attentional control may moderate pain-related attentional biases. There is also weak evidence of interpretation bias in youth with chronic pain compared with those without.

The Treatment of Acute Pain in the Emergency Department: A White Paper Position Statement Prepared for the American Academy of Emergency Medicine

Background

Pain is one of the most common reasons patients present to the emergency department (ED). Emergency physicians should be aware of the numerous opioid and nonopioid alternatives available for the treatment of pain.

Impact of a Regional Pharmacy Call Center on Telephone Access Metrics Within the Veterans Health Administration

Purpose:

To establish a cost-effective centralized pharmacy call center to serve the patients of Veterans Integrated Service Network (VISN) 11 that would meet established performance metrics.

Methods:

A pilot project began in August 2011 with the Indianapolis VA Medical Center (VAMC) and the Health Resource Center (HRC) in Topeka, Kansas. The Indianapolis VAMC used a first-call resolution business model consisting of pharmacy technicians receiving tier 1 phone calls that could be escalated to a tier 2 line that consisted of lead technicians and pharmacists, while the HRC utilized general telephone agents that would transfer unresolved calls to the primary facility. Pre- and post-VISN 11 Pharmacy Call Center performance metrics were compared for each of the 7 facilities in the network with the goals being monthly average abandoned call rate less than 5% and average speed to answer less than 30 seconds. Cost per call was also compared.

Results:

The average abandoned call rate for the network during the year prior to VISN 11 Pharmacy Call Center implementation (August 2010-July 2011) was 15.66% and decreased to 3% in July 2014. The average abandoned call rate decreased for each individual facility. In fiscal year 2014, the VISN 11 Pharmacy Call Center was operating at a cost of $4.35 per call while providing more services than the HRC, resulting in less workload being transferred back to the individual facilities.

Conclusion:

A centralized VISN pharmacy call center is a reasonable alternative to individual facility call centers or the HRC.