Expression of Chondrogenic Potential Markers in Cultured Chondrocytes from the Human Knee Joint.

OBJECTIVES: While substantial progress has been made in engineering cartilaginous constructs for animal models, further research is needed to translate these methodologies for human applications. Evidence suggests that cultured autologous chondrocytes undergo changes in phenotype and gene expression, thereby affecting their proliferation and differentiation capacity. This study was designed to evaluate the expression of chondrogenic markers in cultured human articular chondrocytes from passages 3 (P3) and 7 (P7), beyond the current clinical recommendation of P3. METHODS: Cultured autologous chondrocytes were passaged from P3 up to P7, and quantitative polymerase chain reaction (qPCR) was used to assess mRNA expression of chondrogenic markers, including collagen type I (COLI), collagen type II (COLII), aggrecan (AGG), bone morphogenetic protein 4 (BMP4), transcription factor SOX-9 (SOX9), proteoglycan 4 (PGR4), and transformation-related protein 53 (p53), between P3 and P7. RESULTS: Except for AGG, no significant differences were found in the expression of markers between passages, suggesting the maintenance of chondrogenic potential in cultured chondrocytes. Differential expression identified between SOX9 and PGR4, as well as between COLI and SOX9, indicates that differences in chondrogenic markers are present between age groups and sexes, respectively. CONCLUSIONS: Overall, expression profiles of younger and male chondrocytes exhibit conversion of mature cartilage characteristics compared to their counterparts, with signs of dedifferentiation and loss of phenotype within-group passaging. These results may have implications in guiding the use of higher passaged chondrocytes for engineering constructs and provide a foundation for clinical recommendations surrounding the repair and treatment of articular cartilage pathology in both sexes.

Exploring the use of rating scales with entrustment anchors in workplace-based assessment.

PURPOSE: Competency-based medical education (CBME) has prompted widespread implementation of workplace-based assessment (WBA) tools using entrustment anchors. This study aimed to identify factors that influence faculty's rating choices immediately following assessment and explore their experiences using WBAs with entrustment anchors, specifically the Ottawa Surgical Competency Operating Room Evaluation scale. METHOD: A convenience sample of 50 semi-structured interviews with Emergency Medicine (EM) physicians from a single Canadian hospital were conducted between July and August 2019. All interviews occurred within two hours of faculty completing a WBA of a trainee. Faculty were asked what they considered when rating the trainee's performance and whether they considered an alternate rating. Two team members independently analysed interview transcripts using conventional content analysis with line-by-line coding to identify themes. RESULTS: Interviews captured interactions between 70% (26/37) of full-time EM faculty and 86% (19/22) of EM trainees. Faculty most commonly identified the amount of guidance the trainee required as influencing their rating. Other variables such as clinical context, trainee experience, past experiences with the trainee, perceived competence and confidence were also identified. While most faculty did not struggle to assign ratings, some had difficulty interpreting the language of entrustment anchors, being unsure whether their assessment should be retrospective or prospective in nature, and if/how the assessment should change whether they were 'in the room' or not. CONCLUSIONS: By going to the frontline during WBA encounters, this study captured authentic and honest reflections from physicians immediately engaged in assessment using entrustment anchors. While many of the factors identified are consistent with previous retrospective work, we highlight how some faculty consider factors outside the prescribed approach and struggle with the language of entrustment anchors. These results further our understanding of 'in-the-moment' assessments using entrustment anchors and may facilitate effective faculty development regarding WBA in CBME.

Sacro-Iliac Joint Sensory Block and Radiofrequency Ablation: Assessment of Bony Landmarks Relevant for Image-Guided Procedures.

Image-guided sensory block and radiofrequency ablation of the nerves innervating the sacro-iliac joint require readily identifiable bony landmarks for accurate needle/electrode placement. Understanding the relative locations of the transverse sacral tubercles along the lateral sacral crest is important for ultrasound guidance, as they demarcate the position of the posterior sacral network (S1-S3 ± L5/S4) innervating the posterior sacro-iliac joint. No studies were found that investigated the spatial relationships of these bony landmarks. The purpose of this study was to visualize and quantify the interrelationships of the transverse sacral tubercles and posterior sacral foramina to inform image-guided block and radiofrequency ablation of the sacro-iliac joint. The posterior and lateral surfaces of 30 dry sacra (15 M/15 F) were digitized and modeled in 3D and the distances between bony landmarks quantified. The relationships of bony landmarks (S1-S4) were not uniform. The mean intertubercular and interforaminal distances decreased from S1 to S4, whereas the distance from the lateral margin of the posterior sacral foramina to the transverse sacral tubercles increased from S1 to S3. The mean intertubercular distance from S1 to S3 was significantly (p < 0.05) larger in males. The interrelationships of the sacral bony landmarks should be taken into consideration when estimating the site and length of an image-guided strip lesion targeting the posterior sacral network.

Neuromuscular partitioning of the gastrocnemius based on intramuscular nerve distribution patterns: implications for injections

Spasticity of the gastrocnemius is commonly treated with botulinum toxin injections; however, the optimal injection sites within each head have not been evaluated in relation to neuromuscular partitions. The purpose of the present study was to (1) document the intramuscular innervation patterns of the medial and lateral heads of gastrocnemius using 3 dimensional modeling; (2) determine if the medial and lateral heads of gastrocnemius are neuromuscularly partitioned; and (3) propose botulinum toxin injection strategies based on these findings. In this cadaveric study (n=24) the extramuscular and intramuscular innervation was serially dissected followed by digitization and 3D reconstruction and/or photography of the innervation pattern throughout the muscle volume. Intramuscular innervation patterns were defined to determine if the heads of gastrocnemius were neuromuscularly partitioned and based on these findings approaches for botulinum toxin injections were proposed. In all specimens except one, both heads of the gastrocnemius received independent innervation from three discrete nerve branches. Therefore, each head had three neuromuscular partitions defined by location as superior, inferomedial and inferolateral. In one specimen, the lateral head also received nerve branches via the soleus that innervated the inferolateral partition distally. Functionally, independent activation of the neuromuscular partitions of the gastrocnemius may result in differential contribution of the partitions to knee flexion and ankle plantarflexion. To capture all partitions, four injection sites into each belly were proposed. Future clinical studies are needed to determine if there is improved spasticity reduction by targeting neuromuscular partitions

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Enhancement of artemisinin concentration and yield in response to optimization of nitrogen and potassium supply to Artemisia annua.

BACKGROUND AND AIMS: The resurgence of malaria, particularly in the developing world, is considerable and exacerbated by the development of single-gene multi-drug resistances to chemicals such as chloroquinone. Drug therapies, as recommended by the World Health Organization, now include the use of antimalarial compounds derived from Artemisia annua--in particular, the use of artemisinin-based ingredients. Despite our limited knowledge of its mode of action or biosynthesis there is a need to secure a supply and enhance yields of artemisinin. The present study aims to determine how plant biomass can be enhanced while maximizing artemisinin concentration by understanding the plant's nutritional requirements for nitrogen and potassium. METHODS: Experiments were carried out, the first with differing concentrations of nitrogen, at 6, 31, 56, 106, 206 or 306 mg L(-1) being applied, while the other differing in potassium concentration (51, 153 or 301 mg L(-1)). Nutrients were supplied in irrigation water to plants in pots and after a growth period biomass production and leaf artemisinin concentration were measured. These data were used to determine optimal nutrient requirements for artemisinin yield. KEY RESULTS: Nitrogen nutrition enhanced plant nitrogen concentration and biomass production successively up to 106 mg N L(-1) for biomass and 206 mg N L(-1) for leaf nitrogen; further increases in nitrogen had no influence. Artemisinin concentration in dried leaf material, measured by HPLC mass spectroscopy, was maximal at a nitrogen application of 106 mg L(-1), but declined at higher concentrations. Increasing potassium application from 51 to 153 mg L(-1) increased total plant biomass, but not at higher applications. Potassium application enhanced leaf potassium concentration, but there was no effect on leaf artemisinin concentration or leaf artemisinin yield. CONCLUSIONS: Artemisinin concentration declined beyond an optimal point with increasing plant nitrogen concentration. Maximization of artemisinin yield (amount per plant) requires optimization of plant biomass via control of nitrogen nutrition.

Effect of long-term aspirin use on embolic events in infective endocarditis.

BACKGROUND: In a recent clinical trial, aspirin therapy was initiated approximately 34 days after the onset of symptoms but did not reduce the risk of embolism in patients with endocarditis. However, it is possible that aspirin used early in the course of the disease may be beneficial. The purpose of the study is to assess the effect of long-term daily aspirin use on the risk of embolic events in patients with infective endocarditis. METHODS: The clinical characteristics and outcomes of patients excluded from the Multi-Centre Aspirin Trial in Infective Endocarditis because of long-term aspirin use (n = 84) were compared with the data for patients randomized to the placebo arm (n = 55). The former patients took aspirin before and during the early stages of infective endocarditis, whereas the latter patients were not exposed to aspirin before and during the entire hospitalization. Logistic modeling was used to assess the effect of long-term aspirin use on embolism and bleeding. RESULTS: There was a trend toward excess bleeding in long-term aspirin recipients, compared with placebo recipients (P = .065). Logistic modeling revealed that long-term aspirin use may be associated with excess bleeding (unadjusted odds ratio, 2.35 [P = .059]; adjusted odds ratio, 2.08 [P = .118]), but it had no impact on the risk of embolic events in either model. CONCLUSIONS: In patients with endocarditis, long-term daily use of aspirin does not reduce the risk of embolic events but may be associated with a higher risk of bleeding. In the acute phase of endocarditis, aspirin should be used with caution.

A randomized trial of aspirin on the risk of embolic events in patients with infective endocarditis.

OBJECTIVES: This study examined the effect of aspirin on the risk of embolic events in infective endocarditis (IE). BACKGROUND: Embolism is a major complication of IE, and studies in animal models have shown that platelet inhibition with aspirin can lead to more rapid vegetation resolution and a lower rate of embolic events. METHODS: We conducted a randomized, double-blinded, placebo-controlled trial of aspirin treatment (325 mg/day) for four weeks in patients with IE to test the hypothesis that the addition of aspirin would reduce the incidence of clinical systemic embolic events. Patients with perivalvular abscess were excluded. Serial cerebral computed tomograms and transesophageal echocardiograms were obtained in a subset of patients. RESULTS: During the four-year study period, 115 patients were enrolled: 60 assigned to aspirin and 55 assigned to placebo. Embolic events occurred in 17 patients (28.3%) on aspirin and 11 patients (20.0%) on placebo, with an odds ratio (OR) of 1.62 (95% confidence interval [CI] 0.68 to 3.86, p = 0.29). There was a trend toward a higher incidence of bleeding in the patients taking aspirin versus placebo (OR 1.92, 95% CI 0.76 to 4.86, p = 0.075). Development of new intracranial lesions was similar in both groups. Aspirin had no effect on vegetation resolution and valvular dysfunction. CONCLUSIONS: In endocarditis patients already receiving antibiotic treatment, the addition of aspirin does not appear to reduce the risk of embolic events and is likely associated with an increased risk of bleeding. Aspirin is not indicated in the early management of patients with IE.