The acute effects of dietary nitrate supplementation on postmenopausal endothelial resistance to ischemia reperfusion injury: A randomized, placebo-controlled, double blind, crossover clinical trial.

Postmenopausal cardiovascular health is a critical determinant of longevity. Consumption of beetroot juice (BR) and other nitrate rich foods is a safe, effective non-pharmacological intervention strategy to increase systemic bioavailability of the vasoprotective molecule, nitric oxide (NO), through the exogenous nitrate (NO3-)-nitrite (NO2-)-NO pathway. We hypothesized that a single dose of nitrate-rich beetroot juice (BRnitrate 600 mg NO3- / 140 mL, BRplacebo ~ 0 mg/ 140 mL) would improve resting endothelial function and resistance to ischemia-reperfusion (IR) injury to a greater extent in early- (1-6 years following their final menstrual period (FMP), n=12) compared to late- (6+ years after FMP, n=12) postmenopausal women. Analyses with general linear models revealed a significant (p<0.05) time*treatment interaction effect for brachial artery adjusted FMD. Pairwise comparisons revealed adjusted FMD was significantly lower following IR-injury in comparison to all other time points with BRplacebo (Early FMD 2.51 ± 1.18%, Late FMD 1.30 ± 1.10, p<0.001) and was lower than post-IR with BRnitrate (Early FMD 3.84 ± 1.21%, Late FMD 3.21 ± 1.13 %, p=0.014). Considering the postmenopausal stage-dependent variations in endothelial responsiveness to dietary nitrate at rest and post-IR, we predict differing mechanisms underpin macrovascular protection against IR injury. NCT03644472.

How to design and implement a Group Poem activity.

Museum-based learning activities provide interactive and innovative ways to integrate the arts and humanities into medical education. Like other museum-based activities, the Group Poem supports the development of multiple clinically relevant skills and attributes, such as observation, communication, perspective-taking, empathy, and implicit bias awareness. In this paper, we present a step-by-step guide for educators seeking to design and implement a museum-based Group Poem activity for medical learners. The overall 'task' of the activity is for learners to collectively create a poem that they perform for others, a process that participants find to be engaging and meaningful to their formation as physicians. In this paper, we provide specific directions on pre-selecting the works of art, preparing the supplies, dividing into small groups, providing iterative instructions to learners, managing the timing of the session, and debriefing the activity. Although designed to be experienced in an art museum, we note that the Group Poem activity can also be conducted in the classroom or virtually using photographic or digital reproductions of artwork.

Inorganic nitrate supplementation and blood flow restricted exercise tolerance in post-menopausal women.

Exercise tolerance appears to benefit most from dietary nitrate (NO3-) supplementation when muscle oxygen (O2) availability is low. Using a double-blind, randomized cross-over design, we tested the hypothesis that acute NO3- supplementation would improve blood flow restricted exercise duration in post-menopausal women, a population with reduced endogenous nitric oxide bioavailability. Thirteen women (57-76 yr) performed rhythmic isometric handgrip contractions (10% MVC, 30 per min) during progressive forearm blood flow restriction (upper arm cuff gradually inflated 20 mmHg each min) on three study visits, with 7-10 days between visits. Approximately one week following the first (familiarization) visit, participants consumed 140 ml of NO3- concentrated (9.7 mmol, 0.6 gm NO3-) or NO3-depleted beetroot juice (placebo) on separate days (≥7 days apart), with handgrip exercise beginning 100 min post-consumption. Handgrip force recordings were analyzed to determine if NO3- supplementation enhanced force development as blood flow restriction progressed. Nitrate supplementation increased plasma NO3- (16.2-fold) and NO2- (4.2-fold) and time to volitional fatigue (61.8 ± 56.5 s longer duration vs. placebo visit; p = 0.03). Nitrate supplementation increased the rate of force development as forearm muscle ischemia progressed (p = 0.023 between 50 and 75% of time to fatigue) with non-significant effects thereafter (p = 0.052). No effects of nitrate supplementation were observed for mean duration of contraction or relaxation rates (all p > 0.150). These results suggest that acute NO3- supplementation prolongs time-to-fatigue and speeds grip force development during progressive forearm muscle ischemia in postmenopausal women.

Neoadjuvant Short-Course Radiotherapy for Upper Third Rectal Tumors: Systematic Review and Individual Patient Data Metaanalysis of Randomized Controlled Trials.

BACKGROUND: There is no consensus on the use of neoadjuvant radiotherapy for tumors of the upper third of the rectum. Due to conflicting findings in high-quality trials and significant long-term side effects associated with neoadjuvant radiotherapy, the benefit of neoadjuvant radiotherapy for upper third rectal tumors is less certain than for lower two third rectal tumors. This metaanalysis compares oncological outcomes with neoadjuvant radiotherapy and surgery versus surgery alone for upper third rectal tumors. PATIENTS AND METHODS: PubMed, Embase, and the Cochrane library databases were searched. Randomized controlled trials (RCT) comparing neoadjuvant radiotherapy and surgery versus surgery alone for resectable rectal cancer were included. Individual patient data were sought from the principal investigator of each eligible trial for comparative data on patients with upper third rectal tumors. The main outcomes measured were survival outcomes, oncological outcomes, postoperative morbidity, and late toxicity. RESULTS: Individual patient data from two RCTs examining outcomes in 758 patients were obtained. Published data from one further RCT containing comparable data on upper third rectal tumors were included in analysis of local recurrence. In patients with curative surgery, there was no significant reduction in local recurrence or significant improvement in overall survival or disease-free survival with neoadjuvant radiotherapy (LR RR: 0.38, 95% CI 0.14-1.04, p = 0.06) (OS RR: 1.10, 95% CI 0.98-1.24, p = 0.11) (DFS RR: 1.11, 95% CI 0.97-1.26, p = 0.13). CONCLUSIONS: The benefit of neoadjuvant radiotherapy for upper third rectal tumors is not certain, and surgery alone for patients with potentially curative disease at preoperative staging may be sufficient.

Manufacture of High-Performance Tidal Turbine Blades Using Advanced Composite Manufacturing Technologies.

After wind and solar energy, tidal energy presents the most prominent opportunity for generating energy from renewable sources. However, due to the harsh environment that tidal turbines are deployed in, a number of design and manufacture challenges are presented to engineers. As a consequence of the harsh environment, the loadings on the turbine blades are much greater than that on wind turbine blades and, therefore, require advanced solutions to be able to survive in this environment. In order to avoid issues with corrosion, tidal turbine blades are mainly manufactured from fibre reinforced polymer composite material. As a result, the main design and manufacture challenges are related to the main structural aspects of the blade, which are the spar and root, and the connection between the blade and the turbine hub. Therefore, in this paper, a range of advanced manufacturing technologies for producing a 1 MW tidal turbine blade are developed. The main novelty in this study comes with the challenges that are overcome due to the size of the blade, resulting in thickness composite sections (> 130 mm in places), the fast changes in geometry over a short length that isn't the case for wind blades and the required durability of the material in the marine environment. These advances aim to increase the likelihood of survival of tidal turbine blades in operation for a design life of 20 + years.

Effects of acute dietary nitrate supplementation on aortic blood pressures and pulse wave characteristics in post-menopausal women.

PURPOSE: Consumption of nitrate-rich beetroot juice can lower blood pressure in peripheral as well as central arteries and may exert additional hemodynamic benefits (e.g. reduced aortic wave reflections). The specific influence of nitrate supplementation on arterial pressures and aortic wave properties in postmenopausal women, a group that experiences accelerated increases in these variables with age, is unknown. Accordingly, the primary aim of this study was to determine the effect of consuming nitrate-rich beetroot juice on resting brachial and aortic blood pressures (BP) and pulse wave characteristics in a group of healthy postmenopausal women, in comparison to a true (nitrate-free beetroot juice) placebo. METHODS: Brachial (oscillometric cuff) and radial (SphygmoCor) pressures and derived-aortic waveforms were measured during supine rest in thirteen healthy postmenopausal women (63 ±â€¯1 yr) before and 100 min after consumption of 140 ml of either nitrate-rich (9.7 mmol, 0.6 gm NO3-) or nitrate-depleted beetroot juice on randomized visits approximately 10 days apart (cross-over design). Ten young premenopausal women (22 ±â€¯1 yr) served as a reference (non-supplemented) cohort. RESULTS: Brachial and derived-aortic variables showed the expected age-associated differences in these women (all p < 0.05). In post-menopausal women, nitrate supplementation reduced (p < 0.05 vs. placebo visit) brachial systolic BP (BRnitrate -4.9 ±â€¯2.1 mmHg vs BRplacebo +1.1 ± 1.8 mmHg), brachial mean BP (BRnitrate -4.1 ±â€¯1.7 mmHg vs BRplacebo +0.9 ± 1.3 mmHg), aortic systolic BP (BRnitrate -6.3 ±â€¯2.0 mmHg vs BRplacebo +0.5 ± 1.7 mmHg) and aortic mean BP (BRnitrate -4.1 ±â€¯1.7 mmHg vs BRplacebo +0.9 ± 1.3 mmHg), and increased pulse pressure amplification (BRnitrate +4.6 ± 2.0% vs BRplacebo +0.7 ± 2.5%, p = 0.04), but did not alter aortic pulse wave velocity or any other derived-aortic variables (e.g., augmentation pressure or index). CONCLUSIONS: Dietary nitrate supplementation favorably modifies aortic systolic and mean blood pressure under resting conditions in healthy postmenopausal women. Acute supplementation of nitrate does not, however, appear to restore indices of aortic stiffness in this group. Future work should evaluate chronic, long-term effects of this non-pharmacological supplement.

Assessing the usability by clinicians of VISION: A hierarchical display of patient-collected physiological information to clinicians.

BACKGROUND: The inability of patients to accurately and completely recount their clinical status between clinic visits reduces the clinician's ability to properly manage their patients. One way to improve this situation is to collect objective patient information while the patients are at home and display the collected multi-day clinical information in parallel on a single screen, highlighting threshold violations for each channel, and allowing the viewer to drill down to any analog signal on the same screen, while maintaining the overall physiological context of the patient. All this would be accomplished in a way that was easy for the clinician to view and use. METHODS: Patients used five mobile devices to collect six heart failure-related clinical variables: body weight, systolic and diastolic blood pressure, pulse rate, blood oxygen saturation, physical activity, and subjective input. Fourteen clinicians practicing in a heart failure clinic rated the display using the System Usability Scale that, for acceptability, had an expected mean of 68 (SD, 12.5). In addition, we calculated the Intraclass Correlation Coefficient of the clinician responses using a two-way, mixed effects model, ICC (3,1). RESULTS: We developed a single-screen temporal hierarchical display (VISION) that summarizes the patient's home monitoring activities between clinic visits. The overall System Usability Scale score was 92 (95% CI, 87-97), p < 0.0001; the ICC was 0.89 (CI, 0.79-0.97), p < 0.0001. CONCLUSION: Clinicians consistently found VISION to be highly usable. To our knowledge, this is the first single-screen, parallel variable, temporal hierarchical display of both continuous and discrete information acquired by patients at home between clinic visits that presents clinically significant information at the point of care in a manner that is usable by clinicians.

Small bowel perforation due to ingested frog bone: a case report.

Perforation of the gastrointestinal tract by ingested foreign body is an uncommon surgical emergency, most typically associated with the consumption of fish and chicken bones. We present an unusual case of a gentleman presenting emergently with an acute abdomen following ingestion of a meal containing frog meat. Emergent computed tomography (CT) revealed findings suggestive of jejunal perforation due to a foreign body. At laparotomy, a mid-jejunal site of perforation was noted due to a protruding piece of fractured frog bone. Washout and primary repair of the small bowel enterotomy were performed, and the patient made an excellent post-operative recovery.

Contemporary approach to cardiogenic shock care: a state-of-the-art review.

Cardiogenic shock (CS) is a time-sensitive and hemodynamically complex syndrome with a broad spectrum of etiologies and clinical presentations. Despite contemporary therapies, CS continues to maintain high morbidity and mortality ranging from 35 to 50%. More recently, burgeoning observational research in this field aimed at enhancing the early recognition and characterization of the shock state through standardized team-based protocols, comprehensive hemodynamic profiling, and tailored and selective utilization of temporary mechanical circulatory support devices has been associated with improved outcomes. In this narrative review, we discuss the pathophysiology of CS, novel phenotypes, evolving definitions and staging systems, currently available pharmacologic and device-based therapies, standardized, team-based management protocols, and regionalized systems-of-care aimed at improving shock outcomes. We also explore opportunities for fertile investigation through randomized and non-randomized studies to address the prevailing knowledge gaps that will be critical to improving long-term outcomes.

Expression of bone morphogenetic protein-6 in dental follicle stem cells and its effect on osteogenic differentiation.

The dental follicle (DF) plays an essential role in tooth eruption via regulation of bone resorption and bone formation. Bone morphogenetic protein-6 (BMP6) expression in the DF is coincident with bone growth in the tooth crypt. DF stem cells (DFSCs) have been shown to possess strong osteogenic capability. This study aims to determine the expression of BMP6 in DFSCs and to elucidate the role of BMP6 in the osteogenesis of DFSCs. DFSCs and their non-stem cell counterpart, DF cells (DFCs), were obtained from the DFs of rat pups. We showed that expression of BMP6 was significantly higher in the DFSCs than in the DFCs. DFSCs lost osteogenic capability during in vitro expansion, and DFSCs in late passages had reduced BMP6 expression as compared to early passages of DFSCs when they were subjected to osteogenic induction. Addition of exogenous human recombinant BMP6 (hrBMP6) to the osteogenic medium dramatically enhanced the osteogenesis of the late-passage DFSCs. Knockdown of BMP6 by short interfering RNA in the DFSCs in early passages resulted in a decrease in osteogenesis, which could be restored by addition of hrBMP6. We concluded that DFSCs need to express high levels of BMP6 to maintain their osteogenesis capability. Increased BMP6 expression seen in vivo in the DF may reflect the activation of DFSCs for osteogenic differentiation for bone growth during tooth eruption.

Competency in trauma surgery: a national survey of trainees and consultants.

BACKGROUND: The current sparsity of surgical trainees' exposure to training in operative trauma surgery is multifactorial. This concern has been addressed in the revised Intercollegiate Surgical Curriculum Programme (ISCP) for general and vascular surgery (2021). In the lead up to its implementation, we aimed to assess both trainee and consultant confidence levels as a surrogate reflection in the core competency operative skills in general emergency trauma surgery, identify individual experience in commonly performed trauma procedures and gauge interest in a career in trauma surgery. METHOD: An online survey was circulated to general surgery and vascular surgery trainees and consultants. Self-reported competencies were assessed using a 1-10 confidence rating scale. Most questions were based on competencies in emergency trauma surgery as set out by the ISCP. RESULTS: Out of 251 surgical trainees and consultants, 119 responded to our survey (47.4% response rate). Less than half (44.1%; n = 52) of respondents had experienced a trauma thoracotomy. Respondents scored 'somewhat' or 'not at all' competent in the majority of competencies assessed. CONCLUSION: Self-reported competencies in operative trauma skills across all subgroups were sub-standard with incremental levels of perceived competence proportional to years of surgical training. Our data supports the necessity of the new curriculum, in addition to modern training pathways with direct exposure to operative trauma surgery involving dedicated trauma centres and networks, and responsibility of training pathways in the provision of training trauma surgery.

Structural analysis of a fibre-reinforced composite blade for a 1 MW tidal turbine rotor under degradation of seawater.

This paper presents a structural performance study of a fibre-reinforced composite blade for a 1 MW tidal turbine rotor blade that was designed for a floating tidal turbine device. The 8-m long blade was manufactured by ÉireComposites Teo and its structural performance was experimentally evaluated under mechanical loading in the Large Structures Research Laboratory at the University of Galway. Composite coupons, applied with an accelerated ageing process, were tested to evaluate the influence of seawater ageing effects on the performance of the materials. The material strength of the composites was found to have a considerable degradation under the seawater ingress. As part of the design stage, a digital twin of the rotor blade was developed, which was a finite-element model based on layered shell elements. The finite-element model was verified to have good accuracy, with a difference of 4% found in the blade tip deflection between the physically measured test results in the laboratory and numerical prediction from the model. By updating the numerical results with the material properties under seawater ageing effects, the structural performance of the tidal turbine blade under the working environment was studied. A negative impact from seawater ingress was found on the blade stiffness, strength and fatigue life. However, the results show that the blade can withstand the maximum design load and guarantee the safe operation of the tidal turbine within its design life under the seawater ingress.