How can the pressure in anti-embolism stockings be maintained during use? Laboratory evaluation of simulated 'wear' and different reconditioning protocols.

BACKGROUND: Deep vein thrombosis is a major global health issue, responsible for thousands of deaths each year. While thrombi can form under a variety of circumstances, lack of mobility significantly increases risk and therefore non-ambulant patients are frequently fitted with anti-embolism stockings on admission to hospital, to aid blood flow, prevent pooling and thus clotting. Anti-embolism stockings are the most widely used non-invasive medical device on the market and are believed to reduce the risk of deep vein thrombosis by 40%. Despite their widespread use in hospitals world-wide, there is remarkably little research addressing their use or reconditioning and a wide variety of different reconditioning protocols are used in hospitals. OBJECTIVE: The objective of this study was to establish the impact of different wear and reconditioning protocols on the pressure delivering ability of anti-embolism stockings. DESIGN/METHODS: A laboratory investigation was undertaken to evaluate the pressure delivering ability of 2 major global brands of anti-embolism stockings over 5-8days of simulated wear (extension on static cylinders) and 4 different reconditioning protocols. 1 set of samples was continuously 'worn' for 8days without reconditioning, 1 set of samples was 'worn' for 5days with a day of relaxation between each day of 'wear', 1 set was 'hand washed' and 1 set was machine washed and then allowed to relax between each day of 'wear'. The pressure was measured at the beginning and end of each period of 'wear'. SETTING: This study was undertaken in a conditioned textile testing laboratory that complies with BS EN ISO 139:2005+A1:2011. RESULTS: The pressure exerted by anti-embolism stockings reduced by between 15 and 24% after 24h of wear, it reduced by between 21 and 32% when worn continuously for 8days. Allowing stockings to rest for a day between days of wear allowed them to recover slightly but this recovery was only temporary. Washing stockings regenerated their pressure delivering potential significantly and machine washing allowed some to recover to exert more pressure than they had when new. CONCLUSIONS: Different brands of anti-embolism stockings exert different pressures on the same size of leg, when correctly fitted. The pressure exerted by anti-embolism stockings decreases with use but the correct pressure gradient is maintained if correctly fitted. Washing stockings after 24h of wear is effective in restoring their pressure delivering abilities and in some cases can surpass their 'as new' pressure delivering ability.

Impact of Moisture on the Pressure Delivering Potential of Pressure Garments.

Pressure garments are the main method of treatment and prophylaxis for hypertrophic burn scars. The pressure they exert on the scarred skin prevents contractures forming, reduces the itchiness and pruritus associated with active hypertrophic scars, and is believed, by many, to hasten normalization of the scar tissue. The pressure exerted is believed to be critical to treatment success and can be predicted based on laboratory measurement of the fabric's tension profile. All previous research on the pressures delivered by pressure garments has been undertaken using dry fabrics in either laboratory or clinical conditions. However, many patients have complained of increased perspiration when wearing pressure garments, and many burn victims live and work in hot conditions where high levels of perspiration may be expected. This article investigated the impact of moisture content on fabric tension and thus the pressure exerting ability of pressure garments. Four different fabrics currently used in the construction of pressure garments were evaluated in seven different states of "wetness" from completely dry to completely saturated in water or artificial perspiration. Standard laboratory methods were used to measure the initial tension in fabrics and the tension after 11 cycles of extension. Pressures that would be exerted by these fabrics were calculated using the Laplace law. The results of this study showed that the tension, and therefore pressure delivering ability, of fabrics used in pressure garments was significantly reduced when they were wet but that the amount or type of "wetness" did not have a significant effect on pressure delivering ability.

Biomechanical and ergonomic assessment of urban transit operators.

BACKGROUND: The prevalence of neck and low back musculoskeletal injuries in transit operators has been shown to be high; with work absences exceeding double the National average. There is a lack of biomechanical data generated from field researches to inform on musculoskeletal risk associated with transportation and driving occupations. Instead there has been a reliance on simulated driving and questionnaire-based research. OBJECTIVES: This study was designed to examine the musculoskeletal and biomechanical stresses experienced by urban bus drivers. The main objective was to obtain a baseline understanding of sitting posture, muscle activiation and subjective ratings of stress during regular driving tasks. PARTICIPANTS: Fifteen urban city bus drivers were recruited for this study. METHODS: Bus drivers drove the same 65-minute bus route once, at the same time of day, in the same preselected bus. Wireless surface electromyography monitored muscular activity of the drivers' neck, upper trapezius, and erector spinae and video analysis and seat pressure mapping was used to monitor changes in driving posture. A health and lifestyle questionnaire was administered to record specific neck and back pain experienced by drivers as well as to provide lifestyle habits. RESULTS: Drivers were found to exhibit non-neutral postures for less than 30% of the time while conducting routine tasks of turning and stopping for passenger loading and unloading. The neck posture was the greatest concern in terms of non-neutral posture and this was supported by the higher muscle activation to the neck musculature. There was significant posture adjustment made during the one-hour driving period with the adjustments increasing with driving time. CONCLUSION: Activities associated with bus driving appear to require the use of non-neutral postures an increase in muscle activation. Significant postural adjustments were needed over the one-hour observation period suggesting that the musculoskeletal demands may increase over a regular 12-hour shift.

Suppression of cellular immunity by cord blood-derived unrestricted somatic stem cells is cytokine-dependent.

Unrestricted somatic stem cells (USSC) have the potential to differentiate into tissues derived from all three germinal layers and therefore hold promise for use in regenerative therapies. Furthermore, they have haematopoietic stromal activity, a characteristic that may be exploited to enhance haematopoietic engraftment. Both applications may require USSC to be used in an allogeneic, HLA-mismatched setting. We have therefore studied their in vitro interaction with cellular immunity. USSC showed no allostimulatory activity and caused only minimal inhibition of allogeneic T-cell responses. However, following pre-stimulation with IFNgamma and TNFalpha, they inhibited T-cell proliferation in an indoleamine 2, 3-dioxygenase-dependent manner and suppressed graft-versus-host type reactions. In addition, USSC inhibited DC maturation and function. This inhibition was overridden by stronger DC maturation signals provided by IL-1beta, IL-6, PGE(2) and TNFalpha compared to TNFalpha alone. Pre-stimulation of USSC with IFNgamma and TNFalpha had a similar effect: Inhibition of DC maturation was no longer observed. Thus, USSC are conditionally immunosuppressive, and IFNgamma and TNFalpha constitute a switch, which regulates their immunological properties. They either suppress T-cell responses in the presence of both cytokines or in their absence block DC differentiation and function. These activities may contribute to fine-tuning the immune system especially at sites of tissue damage in order to ensure appropriate differentiation of USSC and subsequent tissue repair. Therapeutically, they may help to protect USSC and possibly their progeny from immune rejection.

The impact of design variables and aftercare regime on the long-term performance of pressure garments.

We sought to establish the impact of pressure garment design variables, moisturizer use, and laundry method on the ability of pressure garments to maintain their pressure delivering potential, indicated here by garment tension, over time and use. Twenty-six sets of three replicate pressure garment sleeves were constructed from four powernet fabrics, using three reduction factors and six sleeve dimensions. These pressure garment sleeves were extended for 23 hours on static cylinder models followed by hand or machine laundry up to 28 times. Some sleeves were additionally exposed to moisturizers during their extension. Garment tension and dimensions were measured before and during the simulated wear and wash period to indicate each garment's ability to maintain its tension and therefore pressure throughout a period of "use." The results of the investigation were analyzed in groups where each group contained only 1 variable, thereby allowing the variables with the most significant impact on tension degradation to be identified. The investigation confirmed that all pressure garments lost tension and therefore pressure delivering ability over time and use. It further revealed that pressure garments designed to exert greater pressures degraded faster than those designed to exert lower pressures. Contact between pressure garments and moisturizers accelerated tension degradation, and machine-washing pressure garments tended to prolong their pressure-delivering properties compared with hand-washing them. To maintain the initial pressure delivered by pressure garments, powernet fabrics should be prestressed before being designed/constructed and they should be machine-washed by patients.

Adult human fibroblasts are potent immunoregulatory cells and functionally equivalent to mesenchymal stem cells.

Bone marrow mesenchymal stem cells (MSC) have potent immunosuppressive properties and have been advocated for therapeutic use in humans. The nature of their suppressive capacity is poorly understood but is said to be a primitive stem cell function. Demonstration that adult stromal cells such as fibroblasts (Fb) can modulate T cells would have important implications for immunoregulation and cellular therapy. In this report, we show that dermal Fb inhibit allogeneic T cell activation by autologously derived cutaneous APCs and other stimulators. Fb mediate suppression through soluble factors, but this is critically dependent on IFN-gamma from activated T cells. IFN-gamma induces IDO in Fb, and accelerated tryptophan metabolism is at least partly responsible for suppression of T cell proliferation. T cell suppression is reversible, and transient exposure to Fb during activation reprograms T cells, increasing IL-4 and IL-10 secretion upon restimulation. Increased Th2 polarization by stromal cells is associated with amelioration of pathological changes in a human model of graft-vs-host disease. Dermal Fb are highly clonogenic in vitro, suggesting that Fb-mediated immunosuppression is not due to outgrowth of rare MSC, although dermal Fb remain difficult to distinguish from MSC by phenotype or transdifferentiation capacity. These results suggest that immunosuppression is a general property of stromal cells and that dermal Fb may provide an alternative and accessible source of cellular therapy.