History and Trends of 3D Bioprinting.

The field of bioprinting is rapidly evolving as researchers innovate and drive the field forward. This chapter provides a brief overview of the history of bioprinting from the first described printer system in the early 2000s to present-day relatively inexpensive commercially available units and considers the current state of the field and emerging trends, including selected applications and techniques.

Interaction of material stiffness and negative pressure to enhance differentiation of bone marrow-derived stem cells and osteoblast proliferation.

Negative pressure wound therapy (NPWT) results in improved wound repair and the combined use of NPWT with elastomeric materials may further stimulate and accelerate tissue repair. No firmly established treatment modalities using both NPWT and biomaterials exist for orthopedic application. The goal of this study was to investigate the response of osteoblasts and bone marrow-derived mesenchymal stem cells to negative pressure and to determine whether a newly developed elastic osteomimetic bone repair material (BRM), a blend of type I collagen, chondroitin 6-sulfate, and poly (octanediol citrate) could enhance the osteoblastic phenotype.

Gradient Poly(ethylene glycol) Diacrylate and Cellulose Nanocrystals Tissue Engineering Composite Scaffolds via Extrusion Bioprinting.

Bioprinting has advanced drastically in the last decade, leading to many new biomedical applications for tissue engineering and regenerative medicine. However, there are still a myriad of challenges to overcome, with vast amounts of research going into bioprinter technology, biomaterials, cell sources, vascularization, innervation, maturation, and complex 4D functionalization. Currently, stereolithographic bioprinting is the primary technique for polymer resin bioinks.

Changing Trends of Color of Different Laryngeal Regions in Laryngopharyngeal Reflux Disease.

Introduction: In our previous study, we demonstrated that there might be correlations between laryngopharyngeal reflux disorder and the hue value of laryngoscopic images. And we found that different regions of larynx have different hue values. It was hypothesized that the degree of inflammation varies between different laryngeal regions, due to an acid reflux pattern.

Bioprinting of Cartilage and Skin Tissue Analogs Utilizing a Novel Passive Mixing Unit Technique for Bioink Precellularization.

Bioprinting is a powerful technique for the rapid and reproducible fabrication of constructs for tissue engineering applications. In this study, both cartilage and skin analogs were fabricated after bioink pre-cellularization utilizing a novel passive mixing unit technique. This technique was developed with the aim to simplify the steps involved in the mixing of a cell suspension into a highly viscous bioink.

Polymer microfiber meshes facilitate cardiac differentiation of c-kit(+) human cardiac stem cells.

Electrospun microfiber meshes have been shown to support the proliferation and differentiation of many types of stem cells, but the phenotypic fate of c-kit(+) human cardiac stem cells (hCSCs) have not been explored. To this end, we utilized thin (~5µm) elastomeric meshes consisting of aligned 1.7µm diameter poly (ester-urethane urea) microfibers as substrates to examine their effect on hCSC viability, morphology, proliferation, and differentiation relative to cells cultured on tissue culture polystyrene (TCPS).

Fiber/collagen composites for ligament tissue engineering: influence of elastic moduli of sparse aligned fibers on mesenchymal stem cells.

Electrospun microfibers are attractive for the engineering of oriented tissues because they present instructive topographic and mechanical cues to cells. However, high-density microfiber networks are too cell-impermeable for most tissue applications. Alternatively, the distribution of sparse microfibers within a three-dimensional hydrogel could present instructive cues to guide cell organization while not inhibiting cell behavior.

Static and cyclic mechanical loading of mesenchymal stem cells on elastomeric, electrospun polyurethane meshes.

Biomaterial substrates composed of semi-aligned electrospun fibers are attractive supports for the regeneration of connective tissues because the fibers are durable under cyclic tensile loads and can guide cell adhesion, orientation, and gene expression. Previous studies on supported electrospun substrates have shown that both fiber diameter and mechanical deformation can independently influence cell morphology and gene expression. However, no studies have examined the effect of mechanical deformation and fiber diameter on unsupported meshes.

Cellularized cylindrical fiber/hydrogel composites for ligament tissue engineering.

Electrospun meshes suffer from poor cell infiltration and limited thickness, which restrict their use to thin tissue applications. Herein, we demonstrate two complementary processes to overcome these limitations and achieve elastomeric composites that may be suitable for ligament repair. First, C3H10T1/2 mesenchymal stem cells were incorporated into electrospun meshes using a hybrid electrospinning/electrospraying process.

Tim-3 alters the balance of IL-12/IL-23 and drives TH17 cells: role in hepatitis B vaccine failure during hepatitis C infection.

Hepatitis B virus (HBV) vaccination is recommended for individuals with hepatitis C virus (HCV) infection given their shared risk factors and increased liver-related morbidity and mortality upon super-infection. Vaccine responses in this setting are often blunted, with poor response rates to HBV vaccinations in chronically HCV-infected individuals compared to healthy subjects. In this study, we investigated the role of T cell immunoglobulin mucin domain-3 (Tim-3)-mediated immune regulation in HBV vaccine responses during HCV infection.

Preliminary experimental results from a MARS Micro-CT system.

The Medipix All Resolution System (MARS) system is a commercial spectral/multi-energy micro-CT scanner designed and assembled by the MARS Bioimaging, Ltd. in New Zealand. This system utilizes the state-of-the-art Medipix photon-counting, energy-discriminating detector technology developed by a collaboration at European Organization for Nuclear Research (CERN).

Impaired hepatitis B vaccine responses during chronic hepatitis C infection: involvement of the PD-1 pathway in regulating CD4(+) T cell responses.

Vaccination for hepatitis B virus (HBV) in the setting of hepatitis C virus (HCV) infection is recommended, but responses to vaccination are blunted when compared to uninfected populations. The mechanism for this failure of immune response in HCV-infected subjects remains unknown but is thought to be a result of lymphocyte dysfunction during chronic viral infection. We have recently demonstrated that PD-1, a novel negative immunomodulator for T cell receptor (TCR) signaling, is involved in T and B lymphocyte dysregulation during chronic HCV infection.

The effects of combined cyclic stretch and pressure on the aortic valve interstitial cell phenotype.

Aortic valve interstitial cells (VIC) can exhibit phenotypic characteristics of fibroblasts, myofibroblasts, and smooth muscle cells. Others have proposed that valve cells become activated and exhibit myofibroblast or fibroblast characteristics during disease initiation and progression; however, the cues that modulate this phenotypic change remain unclear. We hypothesize that the mechanical forces experienced by the valve play a role in regulating the native phenotype of the valve and that altered mechanical forces result in an activated phenotype.

Differential regulation of T and B lymphocytes by PD-1 and SOCS-1 signaling in hepatitis C virus-associated non-Hodgkin's lymphoma.

HCV infection is associated with immune dysregulation and B cell Non-Hodgkins lymphoma (HCV-NHL). We have previously shown in vitro that HCV core protein differentially regulates T and B cell functions through two negative signaling pathways, programmed death-1 (PD-1) and suppressor of cytokine signaling-1 (SOCS-1). In this report, we performed a detailed immunologic analysis of T and B cell functions in the setting of HCV-NHL.

PD-1 negatively regulates interleukin-12 expression by limiting STAT-1 phosphorylation in monocytes/macrophages during chronic hepatitis C virus infection.

Hepatitis C virus (HCV) is remarkably efficient at evading host immunity to establish chronic infection. During chronic HCV infection, interleukin-12 (IL-12) produced by monocytes/macrophages (M/Mφ) is significantly suppressed. Programmed death-1 (PD-1), an inhibitory receptor on immune cells, plays a pivotal role in suppressing T-cell responses during chronic viral infection.

Murine Multiple Sleep Latency Test: phenotyping sleep propensity in mice.

Study Objectives: Objectives were to (1) establish a measure of sleep propensity for a more comprehensive characterization of sleepiness in murine genetics and interventional studies and (2) to characterize sample sizes necessary for statistical differences in effect.

Design: Average multiple sleep latency values were compared in mice, varying strain, circadian time, and forced-wakefulness conditions.

Subjects: Adult male mice of inbred strains were studied.

Effectiveness of exercise versus normal activity on acute low back pain: an integrative synthesis and meta-analysis.

There are a variety of protocols used to treat acute low back pain in adults. Therapies currently prescribed include bed rest, normal activity, and exercise therapy. The effectiveness of each of these treatments is controversial.

Stress incontinence in women under 50: does urodynamics improve surgical outcome?

The aim of the study was to determine whether urodynamic testing improves the outcome of retropubic surgery in women aged 50 or younger. A retrospective study was undertaken of 212 women aged 50 or younger who underwent retropubic surgery at a medical school-affiliated hospital between February 1991 and July 1997. Excluded were patients with prior retropubic urethropexy and known low urethral closure pressures.

Germinomas and teratoid siphon anomalies in softshell clams, Mya arenaria, environmentally exposed to herbicides.

Seminomas and dysgerminomas are epizootic in softshell clams, Mya arenaria, from three Maine estuaries contaminated with herbicides. The first epizootic was discovered in 22% of clams collected as Searsport near Long Cove Brook and three culverts that conveyed heating oil and jet fuel spilled from a tank farm in 1971. Data from subsequent epizootiological studies and a series of long-term experimental exposures of softshell clams to no.

Caffeine-metabolizing capability of primary rat hepatocytes, Chinese hamster V79 cells and normal human fibroblasts in culture.

Caffeine is metabolized by primary rat hepatocytes in culture to metabolites similar to those found in rats in vivo, including 6-amino-5-[N-formylmethylamino]-1,3-dimethyluracil, one of the major caffeine metabolites produced in the rat. At a substrate-limiting level of caffeine, the rat hepatocytes metabolized 25-30% of the total added caffeine in 24 h. About 99% of the metabolites was found in the extracellular medium and rinse fractions, suggesting that on a volume basis, caffeine metabolites are in equilibrium inside and outside the cells.