Generalized teleparallel de Sitter geometries

Theories of gravity based on teleparallel geometries are characterized by the torsion, which is a function of the coframe, derivatives of the coframe, and a zero curvature and metric compatible spin-connection. The appropriate notion of a symmetry in a teleparallel geometry is that of an affine symmetry. Due to the importance of the de Sitter geometry and Einstein spaces within General Relativity, we shall describe teleparallel de Sitter geometries and discuss their possible generalizations. In particular, we shall analyse a class of Einstein teleparallel geometries which have a 4-dimensional Lie algebra of affine symmetries, and display two one-parameter families of explicit exact solutions.

The Effect of Insulin and Insulin-like Growth Factor 1 (IGF-1) on Cellular Proliferation and Migration of Human Subacromial Bursa Tissue

Purpose

To evaluate the effect of a one-time dose of insulin or insulin-like growth factor 1 (IGF-1) on cellular proliferation and migration of subacromial bursa tissue (SBT) over time.

Methods

SBT was harvested from over the rotator cuff tendon in 4 consecutive patients undergoing primary arthroscopic rotator cuff repair. SBT was cultured for 3 weeks in complete media until reaching confluence. The culture dishes were stored in a humidified, low oxygen tension (5% CO₂) incubator at 37°C. SBT of each patient underwent treatment with a one-time dose of insulin or IGF-1, whereas nontreated SBT served as a negative control. Cellular proliferation and migration were evaluated after 24, 48, 72, and 96 hours of incubation. SBT-derived cells migrated in the detection field were visualized using fluorescent microscopy.

Results

Cellular proliferation at 24, 48, 72, and 96 hours was 1.40 ± 0.27, 1.00 ± 0.20, 1.47 ± 0.31, and 1.68 ± 0.28 for IGF-1; 1.44 ± 0.24, 1.15 ± 0.27, 1.60 ± 0.36, and 1.61 ± 0.32 for insulin; and 1.51 ± 0.35, 1.29 ± 0.33, 1.53 ± 0.35, and 1.57 ± 0.38 for nontreated SBT. Untreated SBT demonstrated a significantly greater proliferation when compared with IGF-1 and insulin within the first 48 hours, although this effect was found to subside by 96 hours. Cellular migration at 24, 48, 72, and 96 hours was 575.7 ± 45.0, 641.6 ± 77.7, 728.3 ± 122.9, and 752.3 ± 114.5 for IGF-1; 528.4 ± 31.3, 592.5 ± 69.8, 664.2 ± 115.2, and 695.6 ± 148.2 for insulin; and 524.4 ± 41.9, 564.4 ± 49.8, 653.2 ± 81.5, and 685.7 ± 115.5 for nontreated SBT. Insulin showed no difference in migration at each timepoint compared to nontreated SBT (P > .05, respectively).

Conclusions

Insulin and IGF-1 initially inhibit cellular proliferation of human SBT, although this effect was found to subside by 96 hours. Further, neither insulin nor IGF-1 changed the slope of cellular migration over time. However, each treatment group demonstrated a significant increase in cellular proliferation and migration.

Clinical Relevance

In the setting of biologic augmentation of rotator cuff repair, the compatibility and synergistic effect of insulin on human SBT is highly limited.

Analysis of Time to Form Colony Units for Connective Tissue Progenitor Cells (Stem Cells) Harvested From Concentrated Bone Marrow Aspirate and Subacromial Bursa Tissue in Patients Undergoing Rotator Cuff Repair

Purpose

To evaluate the time required for colonies to develop from concentrated bone marrow aspirate (cBMA) and subacromial bursal tissue samples.

Methods

Samples of cBMA and subacromial bursa tissue were harvested from patients undergoing rotator cuff repair surgery between November 2014 and December 2019. Samples were analyzed for time to form colonies and number of colonies formed. The impact of age, sex, and cellularity (cBMA only) was analyzed. Samples were cultured and evaluated daily for colony formation in accordance with the guidelines of the International Society for Cellular Therapy. Demographic factors were analyzed for impact on time to form colonies and number of colonies formed.

Results

Samples of cBMA were obtained from 92 patients. Subacromial bursa tissue was obtained from 54 patients. For cBMA, older age was associated with more days to form colonies (P = .003), but sex (P = .955) and cellularity (P = .623) were not. For bursa, increased age was associated with longer time to form colonies (P = .002) but not sex (P = .804). Conclusions: Increased age (in cBMA and subacromial bursa tissue) and lower initial cellularity (in cBMA) are associated with longer time to form colonies in culture.

Clinical Relevance

Although connective tissue progenitor cells are widely used in orthopaedic practice, there are few metrics to determine their efficacy. Time to form colonies may serve as an important measurement for determining connective tissue progenitor cell viability for augmentation of rotator cuff repair. Subacromial bursa tissue may represent a viable alternative to cBMA for augmentation of rotator cuff repair, capable of forming colonies expediently in vivo.

Intraoperative and In Vitro Classification of Subacromial Bursal Tissue

PURPOSE

To classify subacromial bursal tissue using intraoperative and in vitro characteristics from specimens harvested during arthroscopic shoulder surgery.

METHODS

Subacromial bursa was harvested over the rotator cuff from 48 patients (57 ± 10 years) undergoing arthroscopic shoulder surgery. Specimens were characterized intraoperatively by location (over rotator cuff tendon or muscle), tissue quality (percent of either fatty or fibrous infiltration), and vascularity before complete debridement. Nucleated cell counts were determined after 3 weeks incubation and histological sections were reviewed for degree of fatty infiltration and vascularity. Mesenchymal stem cell surface markers were counted via flow cytometry (n = 3) and cellular migration was observed using a fluoroscopic assay (n = 3).

RESULTS

Intraoperatively, muscle bursa was found most often to have >50% fatty infiltration (n = 39), whereas tendon bursa showed majority fibrous tissue (n = 32). Cellular proliferation did not significantly differ according to intraoperative tissue quality. Intraoperative vascularity was associated with greater proliferation for highly vascular samples (P = 0.023). Tendon bursa demonstrated significantly greater proliferation potential than muscle bursa (P = 0.00015). Histologic assessment of fatty infiltration was moderately correlated with gross tissue fattiness (ρ = -0.626, P = 7.14 × 10^-11). Flow cytometry showed that 90% to 100% of bursal cells were positive for MSC surface markers. Peak cellular migration rates occurred between 18 and 30 hours' incubation.

CONCLUSIONS

Intraoperative and in vitro subacromial bursa characteristics were not found to reliably correlate with the degree of cellular proliferation. However, the anatomic location of subacromial bursa was consistently predictive of increased proliferation potential. Bursa-derived nucleated cells were confirmed to include mesenchymal stem cells with migratory potential.

CLINICAL RELEVANCE

The anatomic distinction between muscle and tendon bursa provides a simple classification for predicting cellular activity.

Bedside Point-of-Care Ultrasound of an Adult with Diffuse Intermittent Abdominal Pain

A 29-year-old woman with a history of obesity status post Roux-en-Y gastric bypass greater than five years prior presented to the emergency department with four hours of sudden-onset stabbing left-sided abdominal pain associated with nausea and non-bloody emesis. She denied melaena and hematochezia, but did report two weeks of diarrhoea that was unchanged with this new onset abdominal pain.

Formative research to identify community partnerships and foster relationships for health promotion research in South Mississippi

OBJECTIVES

The purpose of this short communication is to describe the trust building and collaboration, fostering phases of a community-academic partnership between churches and academic researchers using a community-based participatory research approach.

STUDY DESIGN AND METHODS

An academic-community partnership with church leaders was initiated using survey administration and was further developed using focus groups. A coalition was developed, and it guided a subsequent focus group with church members.

RESULTS

Most churches surveyed did not have a health ministry in place but were agreeable that a variety of health topics were appropriate for the church setting. Church leaders felt that church members were key to engage in health programs in the church, whereas church members viewed pastoral support as important. Church leaders felt that working with a university brings credibility to their own health programs.

CONCLUSION

This early work provides a valuable example of how community collaborations may be initiated and developed using formative research methods, serving both community and research agendas.

Innovation in the occupational health physician profession requires the development of a work collective to improve the efficiency of MSD prevention

Given the ageing population of occupational health physicians and the deteriorating situation of employee health, reforms targeting the multi-disciplinary nature of occupational health are currently being drawn up. These are of great concern to doctors in terms of the future of occupational health, notably with regard to changing medical practices. The objective of this study is to explore the actual practices of occupational health physicians within the framework of MSD prevention in France. By analysing the activity of occupational health physicians, we could gain a better understanding of the coordination between those involved in OHS with the ultimate goal being to improve prevention. Based on an analysis of peer activity, this method made it possible to push beyond pre-constructed discourse. According to activity theories, it is through others that the history and controversies of a profession can be grasped and skills developed. The results produced by these collective discussions on activity analysis contributed to establish a collective point of view about the important aspects of their profession that need defending and the variations in professional genre in relation to the current reforms, notably.

Sustainable MSD prevention: management for continuous improvement between prevention and production. Ergonomic intervention in two assembly line companies

To increase output and meet customers' needs, companies have turned to the development of production management systems: Kaizen, one piece flow, Kanban, etc. The aim of such systems is to accelerate decisions, react to environmental issues and manage various productions. In the main, this type of management system has led to the continuous improvement of production performance. Consequently, such production management systems can have unexpected negative effects on operators' health and safety. Conversely, regulation and control systems focusing on work-related risks have obliged firms to implement health and safety management systems such as OHSAS 18001. The purpose of this type of system, also based on continuous improvement, is to reduce risks, facilitate work-related activities and identify solutions in terms of equipment and tools. However, the prevention actions introduced through health and safety systems often result in other unexpected and unwanted effects on production. This paper shows how companies can improve the way they are run by taking into account both types of management system.

Providing humanistic care: dentists' experiences in deprived areas

Communication barriers severely reduce the effectiveness of oral health care provision to people living in poverty. Our objective was to identify specific approaches and skills developed by dentists for more effective treatment of people living in poverty and addressing their needs. We conducted qualitative research based on in-depth interviews with eight dentists practicing in disadvantaged communities of Montreal, Canada. Analyses consisted of interview debriefing, transcript coding, and data interpretation. Results revealed that, over years of practice, these dentists had developed a five-faceted socio-humanistic approach that involved: (1) understanding patients' social context; (2) taking time and showing empathy; (3) avoiding moralistic attitudes; (4) overcoming social distances; and (5) favoring direct contact with patients. This approach is original, and, even though participants found it successful, it should be evaluated in terms of its impact for access to services and patients' experience of care.

Selective activation of nuclear factor kappa B in the cochlea by sensory and inflammatory stress

Damage response pathways triggered by mechanical stress might reasonably be expected to be conserved throughout evolution. However, using a nuclear factor kappa B (NF-kappaB) reporter mouse we show here that this phylogenetically recent transcription factor plays a major role in the response to mechanosensory stress in the mammalian inner ear. The protective action of NF-kappaB is exerted in neither sensory nor non-sensory epithelial cells, but rather in connective tissue cells within the spiral ligament and spiral limbus. In the spiral ligament, predominantly type I fibrocytes are activated following noise exposure, whereas type II fibrocytes are activated following systemic inflammatory stress. Immune-mediated and acoustic trauma-mediated hearing loss syndromes in humans may in part result from the vulnerability of type II and type I fibrocytes to systemic inflammatory stress and acoustic trauma, respectively. Unexpected cell-specific and stress-specific NF-kappaB activation found in the inner ear in this in vivo study suggest that this approach may have wide applications in demonstrating similar specializations of stress responses in other tissues, including the brain.

Discoidin domain receptor 2 impairs insulin-stimulated insulin receptor substrate-1 tyrosine phosphorylation and glucose uptake in 3T3-L1 adipocytes

Differentiation of preadipocytes into functional adipocytes depends on early proliferative events (mitotic clonal expansion) and extracellular matrix interactions. We report that discoidin domain receptor (DDR) 2, a novel adhesion receptor, is expressed in 3T3-L1 preadipocytes and is downregulated during the early phase of adipogenesis. DDR2 overexpression (DDR2-L1 preadipocytes) reduced subconfluent proliferation by 56% (p<0.001) and insulin-stimulated tyrosine phosphorylation of insulin receptor substrate (IRS)-1 by 34% (p<0.05). The mitotic clonal expansion phase of differentiating confluent DDR2-L1 preadipocytes was impaired by approximately 25% (p<0.05). Although induction of peroxisome proliferator-activated receptor gamma, fatty acid synthase, and adiponectin was not altered, the resulting adipocytes were 55% larger (p<0.05), and contained 66% more triacylglycerol (p<0.01). The induction of CCAAT/enhancer binding protein alpha was reduced by 37% (p<0.05), correlating with a similar reduction in insulin-stimulated IRS-1 tyrosine phosphorylation and glucose transport in DDR2-L1 adipocytes (decreases of 22% and 27%, respectively; p<0.05 for both). Our data show that DDR2 is expressed in adipose cells and that its overexpression leads to insulin resistance.

Macrophage-conditioned medium inhibits the differentiation of 3T3-L1 and human abdominal preadipocytes

AIMS/HYPOTHESIS

In obesity, a limited adipogenic capacity may promote adipocyte hypertrophy and increase the risk of insulin resistance and type 2 diabetes. Recent data indicate that macrophages reside within adipose tissue in obese rodents and humans. We hypothesised that secreted macrophage factors may inhibit adipogenesis.

MATERIALS AND METHODS

Conditioned media from cultured murine J774 or human THP-1 macrophages were collected, and added to either murine 3T3-L1 preadipocytes or human abdominal stromal preadipocytes from subcutaneous or omental fat depots.

RESULTS

Macrophage-conditioned medium (MacCM) strongly inhibited 3T3-L1 adipogenesis. Dose-response studies with J774-MacCM revealed that 80 and 100% of J774-MacCM completely suppressed triacylglycerol accumulation as well as the induction of fatty acid synthase, peroxisome proliferator-activated receptor gamma, CCAAT/enhancer binding protein alpha, and adiponectin. Similar inhibitory effects on 3T3-L1 preadipocytes were observed with THP-1-MacCM. Differentiation of human abdominal subcutaneous stromal preadipocytes was moderately reduced (subcutaneous>omental) by J744-MacCM. In contrast, the differentiation of both subcutaneous and omental stromal preadipocytes was completely inhibited by THP-1-MacCM, as determined on the basis of morphology and triacylglycerol accumulation, as well as fatty acid synthase and adiponectin protein expression.

CONCLUSIONS/INTERPRETATION

Secreted macrophage products inhibit the differentiation of 3T3-L1 preadipocytes as well as human abdominal stromal preadipocytes.

Introducing an evaluation of community based occupational therapy services: a client-centred practice

The results of a study conducted in 1996 by the "Groupe de recherche en ergothérapie communautaire" (GREC), indicate that the quality of occupational therapy services in community settings is infrequently evaluated. A conceptual framework supporting such a process is presented in the context of client-centered services with a focus on continuous health care improvement. Both the research process leading to the design of an assessment tool, and its congruence with the beliefs and values of the profession, are explored. Finally, some issues relating to the implementation of a formal evaluation process are discussed.

Caught up in uroweb

Emphasizing "interactive exchange and discussion" among urologists worlwide, the mission of Uroweb (www.uroweb.org) is to be a global resource for urologic specialists and investigators, although the content is mostly from urologists in Europe and the United States. The European Association of Urology, which developed this World Wide Web site, notes it was born out of the desire to link educational and practical treatment information from a wide variety of sources.

Minimally invasive direct coronary artery bypass surgery

Three patients with isolated disease of the left anterior descending coronary received a minimally invasive direct coronary artery bypass operation. All were discharged from the hospital in 2 days and are doing well. This is an exciting new procedure which combines the long-term benefits of bypass using the mammary artery with a shortened hospital stay and a rapid postoperative recovery.

Everyday memory following traumatic brain injury

Residual memory deficits may represent a problem to the everyday functioning of a large number of people, including those who have sustained traumatic brain injury (TBI). The present exploratory study sought to investigate the interrelationships between subjective memory reports, performance on traditional memory tests, and performance on tests of prospective memory. These interrelationships were contrasted between a group of 24 adults who had sustained TBI and a group of 24 matched control subjects. Prospective memory was hypothesized to be indicative of everyday memory functioning. The results provided preliminary evidence that prospective memory tests are sensitive to TBI-related neurological impairment and, in comparison to traditional tests, may be better indicators of functional memory capacity. This pattern was particularly true for control subjects, possibly because TBI subjects had difficulties in evaluating their memory functioning.

Optimal technetium-99m RBC labeling for gastrointestinal hemorrhage study

Four methods of Tc-99m red blood cell labeling were tested for labeling efficiency and kinetics in normal adults. From a perspective of the gastrointestinal hemorrhage study, the in vivo method was least appropriate because of extravascular loss of pertechnetate. The modified in vitro method was disadvantageous because of long labeling intervals in a syringe fixed to the patient's forearm (45 minutes). The pure in vitro methods produced the highest labeling efficiency (95% +) and are preferred by the authors.

Scintigraphy of gastrointestinal hemorrhage: superiority of 99mTc red blood cells over 99mTc sulfur colloid

The relative efficacy of 99mTc sulfur colloid and in vitro-labeled 99mTc red blood cells in detecting and localizing gastrointestinal hemorrhage was evaluated in a prospective tandem study of 100 patients referred for suspicion of gastrointestinal tract hemorrhage. Thirty-eight true-positive scintigrams were obtained with 99mTc red blood cells, whereas 99mTc sulfur colloid detected only five sites of hemorrhage. Scintigraphic findings were corroborated by clinical, endoscopic, arteriographic, and surgical findings. 99mTc red blood cells were clearly superior, with a sensitivity of 93%, specificity of 95%, and overall accuracy of 94% in detecting and localizing gastrointestinal hemorrhage.