AT2R Activation Improves Wound Healing in a Preclinical Mouse Model.

Abnormal skin healing resulting in chronic wounds or hypertrophic scarring remains a major healthcare burden. Here, the antifibrotic angiotensin II type 2 receptor (AT2R) signaling pathway was modulated to determine its impact on cutaneous wound healing. Balb/c mice received two splinted full-thickness wounds. Topical treatments with the selective AT2R agonist compound 21 (C21) and/or selective antagonist PD123319 or saline vehicle were administered until sacrifice on post-wounding days 7 or 10. The rate of wound re-epithelialization was accelerated by PD123319 and combination treatments. In vitro, C21 significantly reduced human fibroblast migration. C21 increased both collagen and vascular densities at days 7 and 10 post-wounding and collagen I:III ratio at day 10, while PD123319 and combination treatments decreased them. Genes associated with regeneration and repair were upregulated by C21, while PD123319 treatment increased the expression of genes associated with inflammation and immune cell chemotaxis. C21 treatment reduced wound total leukocyte and neutrophil staining densities, while PD123319 increased these and macrophage densities. Overall, AT2R activation with C21 yields wounds that mature more quickly with structural, cellular, and gene expression profiles more closely approximating unwounded skin. These findings support AT2R signal modulation as a potential therapeutic target to improve skin quality during wound healing.

Interprofessional learning about medication safety.

BACKGROUND: Safe medication management requires collaboration between health professionals. APPROACH: A mixed academic and clinician team co-designed and co-facilitated a 2-h interprofessional medication safety workshop, covering medication history taking, perioperative medication management, discharge planning, incident review and dosing and administration calculations. Three workshop sessions were delivered across three sites during September 2019 at a large metropolitan healthcare network. Senior nursing, medical and pharmacy students were invited to participate in the workshops and evaluation. EVALUATION: We evaluated satisfaction, learning experience and perceived clinical application for medical, pharmacy and nursing students. Surveys were conducted immediately after each workshop and at 4 weeks. Quantitative data was analysed descriptively and qualitative data analysed using thematic analysis. Forty-five students participated in the evaluative component of the workshops. Mean student response scores demonstrated a high level of satisfaction with the workshop's relevance and utility to their learning. Students expressed strong agreement that the workshop promoted communication across professions for medication safety. Analysis of the qualitative data identified seven key themes, with consistently positive responses provided in each: interactions within the interprofessional team; recognising the importance of teams; learning the process of medication use; acknowledging and working with difference; role playing; thinking patient safety; and authenticity. IMPLICATIONS: A 2-h interprofessional workshop about medication safety provided positive learning experiences with high satisfaction to medical, nursing and pharmacy students, and had strong perceived applicability to their future clinical practice.

Muscle fiber-type specific terminal Schwann cell pathology leads to sprouting deficits following partial denervation in SOD1G93A mice.

Amyotrophic lateral sclerosis (ALS) is an adult-onset disease characterized by the progressive death of motoneurons and denervation of muscle fibers. To restore motor function, surviving motoneurons in partially denervated muscles typically sprout axons to reinnervate denervated endplates. However, studies on the SOD1G93A rodent models of ALS indicate that sprouting is significantly limited in fast, but not slow, twitch muscles after disease onset. This limitation hastens the rate of muscle weakness and loss of motor function. The causes of this limitation are currently unknown. Sprouting could be limited because the SOD1G93A mutation weakens motoneurons making them incapable of expanding their field of innervation. Alternatively, motoneurons may be capable of sprouting, but unable to do so due to the loss of a permissive sprouting environment. To distinguish between the two possibilities, we compared the sprouting capacity of motoneuron subtypes by partially denervating the fast twitch plantaris (composed of type IIa/IIb muscle fibers) and slow twitch soleus muscles (type I/IIa fibers) prior to disease onset and weakening in SOD1G93A and WT mice. We found that only motoneurons innervating the SOD1G93A plantaris had a limited sprouting capacity. This was correlated with the selective loss of terminal Schwann cells (TSCs) at IIb fibers and an increase in macrophage infiltration. Treating SOD1G93A mice with the tyrosine kinase inhibitor, masitinib, significantly reduced infiltration, prevented TSC loss, and increased the sprouting capacity to near normal. These results suggest that TSCs at denervated type IIb muscle fibers are aberrantly targeted by infiltrating macrophages in SOD1G93A mice, and their loss accounts, at least in part, for the compromised sprouting capacity of the largest motoneurons during early stages of ALS.

The challenge of creating a 'we're all this together' culture in Addenbrooke's theatres.

In the wake of seven consecutive never events in theatres during 2011-2012, senior managers at Addenbrooke's had a challenge--to raise morale and support staff to fully support the WHO surgical safety checklist process. Theatres operations manager Maggie Ward and the theatres team took some innovative steps to change culture in theatres.

Mechanically overloading collagen fibrils uncoils collagen molecules, placing them in a stable, denatured state.

Due to the high occurrence rate of overextension injuries to tendons and ligaments, it is important to understand the fundamental mechanisms of damage to these tissues' primary load-bearing elements: collagen fibrils and their constituent molecules. Based on our recent observations of a new subrupture, overload-induced mode of fibril disruption that we call discrete plasticity, we have sought in the current study to re-explore whether the tensile overload of collagen fibrils can alter the helical conformation of collagen molecules. In order to accomplish this, we have analyzed the conformation of collagen molecules within repeatedly overloaded tendons in relation to their undamaged matched-pair controls using both differential scanning calorimetry and variable temperature trypsin digestion susceptibility. We find that tensile overload reduces the specific enthalpy of denaturation of tendons, and increases their susceptibility to trypsin digestion, even when the digestion is carried out at temperatures as low as 4 °C. Our results indicate that the tensile overload of collagen fibrils can uncoil the helix of collagen molecules, placing them in a stable, denatured state.

Cross-link stabilization does not affect the response of collagen molecules, fibrils, or tendons to tensile overload.

We investigated whether immature allysine-derived cross-links provide mechanically labile linkages by exploring the effects of immature cross-link stabilization at three levels of collagen hierarchy: damaged fibril morphology, whole tendon mechanics, and molecular stability. Tendons from the tails of young adult steers were either treated with sodium borohydride (NaBH4) to stabilize labile cross-links, exposed only to the buffer used during stabilization treatment, or maintained as untreated controls. One-half of each tendon was then subjected to five cycles of subrupture overload. Morphologic changes to collagen fibrils resulting from overload were investigated using scanning electron microscopy, and changes in the hydrothermal stability of collagen molecules were assessed using hydrothermal isometric tension testing. NaBH4 cross-link stabilization did not affect the response of tendon collagen to tensile overload at any of the three levels of hierarchy studied. Cross-link stabilization did not prevent the characteristic overload-induced mode of fibril damage that we term discrete plasticity. Similarly, stabilization did not alter the mechanical response of whole tendons to overload, and did not prevent an overload-induced thermal destabilization of collagen molecules. Our results indicate that hydrothermally labile cross-links may not be as mechanically labile as was previously thought.

Repeated subrupture overload causes progression of nanoscaled discrete plasticity damage in tendon collagen fibrils.

A critical feature of tendons and ligaments is their ability to resist rupture when overloaded, resulting in strains or sprains instead of ruptures. To treat these injuries more effectively, it is necessary to understand how overload affects the primary load-bearing elements of these tissues: collagen fibrils. We have investigated how repeated subrupture overload alters the collagen of tendons at the nanoscale. Using scanning electron microscopy to examine fibril morphology and hydrothermal isometric tension testing to look at molecular stability, we demonstrated that tendon collagen undergoes a progressive cascade of discrete plasticity damage when repeatedly overloaded. With successive overload cycles, fibrils develop an increasing number of kinks along their length. These kinks-discrete zones of plastic deformation known to contain denatured collagen molecules-are accompanied by a progressive and eventual total loss of D-banding along the surface of fibrils, indicating a loss of native molecular packing and further molecular denaturation. Thermal analysis of molecular stability showed that the destabilization of collagen molecules within fibrils is strongly related to the amount of strain energy dissipated by the tendon after yielding during tensile overload. These novel findings raise new questions about load transmission within tendons and their fibrils and about the interplay between crosslinking, strain-energy dissipation ability, and molecular denaturation within these structures.

Telephone referral education, and evidence of retention and transfer after six-months.

BACKGROUND: Effective communication between clinicians is essential for safe, efficient healthcare. We undertook a study to determine the longer-term effectiveness of an education session employing a structured method to teach referral-making skills to medical students. METHODS: All final year medical students received a forty-five minute education intervention consisting: discussion of effective telephone referrals; video viewing and critique; explanation, demonstration and practice using ISBAR; provision of a memory aid for use in their clinical work. Audio recordings were taken during a subsequent standardised simulation scenario and blindly assessed using a validated scoring system. Recordings were taken immediately before (control), several hours after (intervention), and at approximately six months after the education. Retention of the acronym and self-reports of transfer to the clinical environment were measured with a questionnaire at eight months. RESULTS: Referral clarity at six months was significantly improved from pre-intervention, and referral content showed a trend towards improvement. Both measures were lower than the immediate post-education test. The ISBAR acronym was remembered by 59.4% (n = 95/160) and used by the vast majority of the respondents who had made a clinical telephone referral (n = 135/143; 94.4%). CONCLUSIONS: A brief education session improved telephone communication in a simulated environment above baseline for over six months, achieved functional retention of the acronym over a seven to eight month period and resulted in self reports of transfer of the learning into practice.

Six year audit of cardiac arrests and medical emergency team calls in an Australian outer metropolitan teaching hospital.

PROBLEM: In-hospital cardiac arrest often represents failure of optimal clinical care. The use of medical emergency teams to prevent such events is controversial. In-hospital cardiac arrests have been reduced in several single centre historical control studies, but the only randomised prospective study showed no such benefit. In our hospital an important problem was failure to call the medical emergency team or cardiac arrest team when, before in-hospital cardiac arrest, patients had fulfilled the criteria for calling the team. DESIGN: Single centre, prospective audit of cardiac arrests and data on use of the medical emergency team during 2000 to 2005. SETTING: 400 bed general outer suburban metropolitan teaching hospital. STRATEGIES FOR CHANGE: Three initiatives in the hospital to improve use of the medical emergency team: orientation programme for first year doctors, professional development course for medical registrars, and the evolving role of liaison intensive care unit nurses. KEY MEASURES FOR IMPROVEMENT: Incidence of cardiac arrests. EFFECTS OF THE CHANGE: Incidence of cardiac arrests decreased 24% per year, from 2.4/1000 admissions in 2000 to 0.66/1000 admissions in 2005. LESSONS LEARNT: Medical emergency teams can be efficacious when supported with a multidisciplinary, multifaceted education system for clinical staff.

Expression of disulphide-bridge-dependent conformational epitopes and immunogenicity of the carboxy-terminal 19 kDa domain of Plasmodium yoelii merozoite surface protein-1 in live attenuated Salmonella vaccine strains.

The 19 kDa carboxy-terminal domain of Plasmodium yoelii merozoite surface protein-1 (MSP1(19)) was expressed in Salmonella vaccine strains as a carboxy-terminal fusion to fragment C of tetanus toxin (TetC). This study demonstrates that antibodies that recognize disulphide-dependent conformational epitopes in native MSP1 react with the TetC-MSP1(19) fusion protein expressed in Salmonella. The proper folding of MSP1(19) polypeptide is dependent on both the Salmonella host strain and the protein to which the MSP1(19) polypeptide is fused. Serum from mice immunized with Salmonella typhimurium C5aroD expressing TetC-MSP1(19) recognized native MSP1 as shown by immunofluorescence with P. yoelii-infected erythrocytes. Antibody levels to MSP1(19) were highest in out-bred mice immunized with S. typhimurium C5aroD carrying pTECH2-MSP1(19) and antibody was mostly directed against reduction-sensitive conformational epitopes. However, antibody levels were lower than in BALB/c mice immunized with a glutathione S-transferase (GST)-MSP1(19) fusion protein in Freund's adjuvant, and which were protected against P. yoelii challenge infection. In challenge experiments with P. yoelii the Salmonella-immunized mice were not protected, probably reflecting the magnitude of the antibody response. The results of this study have important implications in the design of live multivalent bacterial vaccines against eukaryotic pathogens.