Rheological characterization of cell-laden alginate-gelatin hydrogels for 3D biofabrication.

Biofabrication of tissue models that closely mimic the tumor microenvironment is necessary for high-throughput anticancer therapeutics. Extrusion-based bioprinting of heterogeneous cell-laden hydrogels has shown promise in advancing rapid artificial tissue development. A major bottleneck limiting the rapid production of physiologically relevant tissue models is the current limitation in effectively printing large populations of cells. However, by significantly increasing hydrogel cell-seeding densities, the time required to produce tissues could be effectively reduced. Here, we explore the effects of increasing cell seeding densities on the viscoelastic properties, printability, and cell viability of two different alginate-gelatin hydrogel compositions. Rheological analysis of hydrogels of varying cell seeding densities reveals an inverse relationship between cell concentration and zero-shear viscosity. We also observe that as cell seeding densities increases, the storage moduli decrease, thus lowering the required printing pressures for gel extrusion. We also observe that increasing cell concentration can negatively impact the structural properties of the extruded material by increasing post-print line spreading. We find that hydrogels composed of higher molecular weight alginates and the highest cell-seeding densities (107 cells/mL) yield higher cell viability (>80%) and structural uniformity after printing. The optimized printing parameters determined for the alginate-gelatin bioinks explored may aid in the future rapid fabrication of functional tissue models for therapeutic screening.

Clinical Commentary: Rehabilitation Using Acute Dry Needling for Injured Athletes Returning to Sport and Improving Performance.

Dry needling is most commonly used in the subacute and chronic phases of an injury; therefore, it is imperative to understand the use of dry needling in the acute phases of an injury. There are four main reasons to use dry needling during the acute phase of injury: to relieve pain, decrease edema, increase range of motion and flexibility, and increase strength and power. Dry needling can be used pregame, postgame, during half time or an intermission, or following an injury. Although further research is needed, acute dry needling can be used to bolster athletes' health and possibly improve sports performance.

MoWa: A Disinfectant for Hospital Surfaces Contaminated With Methicillin-Resistant Staphylococcus aureus (MRSA) and Other Nosocomial Pathogens.

Introduction: Staphylococcus aureus strains, including methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA), are a main cause of nosocomial infection in the world. The majority of nosocomial S. aureus-infection are traced back to a source of contaminated surfaces including surgery tables. We assessed the efficacy of a mixture of levulinic acid (LA) and sodium dodecyl sulfate (SDS), hereafter called MoWa, to eradicate nosocomial pathogens from contaminated surfaces. Methods and Results: A dose response study demonstrated that MoWa killed 24 h planktonic cultures of S. aureus strains starting at a concentration of (LA) 8.2/(SDS) 0.3 mM while 24 h preformed biofilms were eradicated with 32/1.3 mM. A time course study further showed that attached MRSA bacteria were eradicated within 4 h of incubation with 65/2 mM MoWa. Staphylococci were killed as confirmed by bacterial counts, and fluorescence micrographs that were stained with the live/dead bacterial assay. We then simulated contamination of hospital surfaces by inoculating bacteria on a surface prone to contamination. Once dried, contaminated surfaces were sprayed with MoWa or mock-treated, and treated contaminated surfaces were swabbed and bacteria counted. While bacteria in the mock-treated samples grew at a density of ~104 cfu/cm2, those treated for ~1 min with MoWa (1.0/0.04 M) had been eradicated below limit of detection. A similar eradication efficacy was obtained when surfaces were contaminated with other nosocomial pathogens, such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, or Staphylococcus epidermidis. Conclusions: MoWa kills planktonic and biofilms made by MRSA and MSSA strains and showed great efficacy to disinfect MRSA-, and MSSA-contaminated, surfaces and surfaces contaminated with other important nosocomial pathogens.

Ballroom dance for persons with multiple sclerosis: a pilot feasibility study.

Purpose: The purpose of this study was to evaluate the exercise intensity and feasibility of recreational ballroom dance for persons with multiple sclerosis (MS).Methods: Seven persons with MS participated in 2 one-hour dance sessions per week for 6 weeks. Dance types included rumba, foxtrot, waltz, and push-pull. Six other persons with MS comprised a control group that did not dance. Heart rate and ratings of perceived exertion (RPE) were monitored during the sessions. Outcomes included: quality of life, fatigue, depression, self-efficacy, timed up and go, Berg Balance Scale, Dynamic Gait Index and the Multiple Sclerosis Functional Composite comprising 9-hole peg test, 25-ft walk test, and Paced Auditory Serial Addition Test (PASAT), a cognitive test.Results: Heart rates and RPE indicated that ballroom dance for persons with MS can provide a light to moderate exercise intensity. After the dance program, quality of life and PASAT improved as did the MS Functional Composite Score. No changes were noted in the control group.Conclusions: Recreational ballroom dance is feasible and can provide an exercise stimulus sufficient to help meet exercise recommendations for persons with multiple sclerosis as well as improve quality of life and cognition in persons with MS.Implications for rehabilitationExercise or physical activity is important for the health and wellness of persons with multiple sclerosis.Persons with multiple sclerosis often seek information about non-traditional low-impact physical activity.In a small controlled sample, partnered recreational ballroom or social dance for persons with multiple sclerosis has been shown to be feasible and of recommended exercise intensity.Further, partnered recreational ballroom dance for persons with multiple sclerosis can improve measures of quality of life and cognitive function.