Recovery time of a plasma-wakefield accelerator.

The interaction of intense particle bunches with plasma can give rise to plasma wakes1,2 capable of sustaining gigavolt-per-metre electric fields3,4, which are orders of magnitude higher than provided by state-of-the-art radio-frequency technology5. Plasma wakefields can, therefore, strongly accelerate charged particles and offer the opportunity to reach higher particle energies with smaller and hence more widely available accelerator facilities. However, the luminosity and brilliance demands of high-energy physics and photon science require particle bunches to be accelerated at repetition rates of thousands or even millions per second, which are orders of magnitude higher than demonstrated with plasma-wakefield technology6,7. Here we investigate the upper limit on repetition rates of beam-driven plasma accelerators by measuring the time it takes for the plasma to recover to its initial state after perturbation by a wakefield. The many-nanosecond-level recovery time measured establishes the in-principle attainability of megahertz rates of acceleration in plasmas. The experimental signatures of the perturbation are well described by simulations of a temporally evolving parabolic ion channel, transferring energy from the collapsing wake to the surrounding media. This result establishes that plasma-wakefield modules could be developed as feasible high-repetition-rate energy boosters at current and future particle-physics and photon-science facilities.

The Role of Bone Sialoprotein in Bone Healing.

Bone sialoprotein (BSP) is a multi-functional extracellular matrix (ECM) protein associated with mineralized tissues, particularly bone and cementum. The amino acid sequence of BSP includes three evolutionarily conserved functional domains which contribute to functions of the protein: an N-terminal collagen-binding domain, polyglutamic acid (polyE) sequences involved in hydroxyapatite nucleation and crystal growth, and a C-terminal arginine-glycine-aspartic acid (RGD) integrin-binding domain. BSP promotes attachment and differentiation of osteogenic and osteoclastic cells. Genetic ablation of BSP in mice results in skeletal and dental developmental defects and impaired bone healing in both appendicular bone and alveolar bone of the jaw. Several studies demonstrated positive effects of BSP on bone healing in rodent models, though other experiments show negligible results. Native (harvested from rat bones) BSP cross-linked to collagen induced slight improvements in calvarial bone healing in rats. Recombinant BSP and collagen delivered in a polylactide (PLA) cylinder improved bone defect healing in rat femurs. Both native and recombinant BSP delivered in a collagen gel improved alveolar bone healing in wild-type and BSP-deficient mice. These advances suggest BSP is a new player in bone healing that has potential to be an alternative or complimentary to other bioactive factors. Future studies are necessary to understand mechanisms of how BSP influences bone healing and optimize delivery and dose in different types of bone defects and injuries.

The antimicrobial drug pyrimethamine inhibits STAT3 transcriptional activity by targeting the enzyme dihydrofolate reductase.

Cancer is often characterized by aberrant gene expression patterns caused by the inappropriate activation of transcription factors. Signal transducer and activator of transcription 3 (STAT3) is a key transcriptional regulator of many protumorigenic processes and is persistently activated in many types of human cancer. However, like many transcription factors, STAT3 has proven difficult to target clinically. To address this unmet clinical need, we previously developed a cell-based assay of STAT3 transcriptional activity and performed an unbiased and high-throughput screen of small molecules known to be biologically active in humans. We identified the antimicrobial drug pyrimethamine as a novel and specific inhibitor of STAT3 transcriptional activity. Here, we show that pyrimethamine does not significantly affect STAT3 phosphorylation, nuclear translocation, or DNA binding at concentrations sufficient to inhibit STAT3 transcriptional activity, suggesting a potentially novel mechanism of inhibition. To identify the direct molecular target of pyrimethamine and further elucidate the mechanism of action, we used a new quantitative proteome profiling approach called proteome integral solubility alteration coupled with a metabolomic analysis. We identified human dihydrofolate reductase as a target of pyrimethamine and demonstrated that the STAT3-inhibitory effects of pyrimethamine are the result of a deficiency in reduced folate downstream of dihydrofolate reductase inhibition, implicating folate metabolism in the regulation of STAT3 transcriptional activity. This study reveals a previously unknown regulatory node of the STAT3 pathway that may be important for the development of novel strategies to treat STAT3-driven cancers.

A novel de novo heterozygous ALPL nonsense mutation associated with adult hypophosphatasia.

Using genetic, clinical, biochemical, and radiographic assessment and bioinformatic approaches, we present an unusual case of adult HPP caused by a novel de novo heterozygous nonsense mutation in the alkaline phosphatase (ALPL). INTRODUCTION: Hypophosphatasia (HPP) is caused by genetic alterations of the ALPL gene, encoding the tissue-nonspecific isozyme of alkaline phosphatase (TNSALP). Here, the purpose was to perform clinical and molecular investigation in a 36-year-old Caucasian woman suspected to present adult HPP. METHODS: Medical and dental histories were obtained for the proposita and family members, including biochemical, radiographic, and dental assessments. ALPL mutational analysis was performed by the Sanger sequencing method, and the functional impact prediction of the identified mutations was assessed by bioinformatic methods. RESULTS: We identified a novel heterozygous nonsense mutation in the ALPL gene (NM_000478.6:c.768G>A; W[TGG]>*[TGA]) associated with spontaneous vertebral fracture, severe back pain, musculoskeletal pain, low bone density, and short-rooted permanent teeth loss. Functional prediction analysis revealed that the Trp256Ter mutation led to a complete loss of TNSALP crown domain and extensive loss of other functional domains (calcium-binding domain, active site vicinity, and zinc-binding site) and over 60% loss of homodimer interface residues, suggesting that the mutant TNSALP molecules are nonfunctional and form unstable homodimers. Genotyping of the ALPL in the proposita's parents, sister, and niece revealed that in this case, HPP occurred due to a de novo mutation. CONCLUSION: The present study describes a novel genotype-phenotype and structure-function relationship for HPP, contributing to a better molecular comprehension of HPP etiology and pathophysiology.

Hepatic and renal toxicity and associated factors among HIV-infected children on antiretroviral therapy: a prospective cohort study.

OBJECTIVES: The aim of the study was to investigate the prevalence of renal function and liver enzyme abnormalities among HIV-infected children, changes in prevalence with time on combination antiretroviral therapy (cART), and the factors associated with these abnormalities. METHODS: A prospective cohort study was conducted among HIV-infected children < 18 years old (n = 705) who were on first-line cART. Liver enzymes, renal function, haematology, immunology and virological response were assessed at enrolment and followed bi-annually for 18 months. Liver fibrosis and cirrhosis were assessed using noninvasive markers including the aspartate aminotransferase (AST) to platelet ratio index (APRI) and fibrosis score (FIB-4). RESULTS: The median age was 12 [interquartile range (IQR) 8-14] years; 53.3% of patients were male. At enrolment, the median cART duration was 3.3 (IQR 1.1-6.1) years; 177 (25.1%) and 83 (11.8%) patients had elevated AST and alanine aminotransferase (ALT), respectively. A tenth of the children had an APRI score > 0.5, suggesting liver fibrosis. Being on a zidovudine (ZDV)- or nevirapine (NVP)-based regimen and having a viral load > 1000 HIV-1 RNA copies/mL were significantly associated with elevated ALT. Twenty-four (3.4%) and 84 (12.1%) patients had elevated creatinine and blood urea nitrogen (BUN), respectively. As cART duration increased by 6 months, median BUN increased by 1.6 [95% confidence interval (CI) 0.4-2.7] mg/dL (P = 0.01); the glomerular filtration rate (GFR) decreased by 35.6 (95% CI 17.7-53.4) mL/min/1.73 m2 (P < 0.0001); and AST and ALT decreased by 1.4 (95% CI 0.4-2.5) IU/L (P = 0.01) and 1.4 (95% CI 0.2-2.6) IU/L (P = 0.01), respectively. CONCLUSIONS: A high prevalence of liver enzyme and renal function abnormalities was observed at enrolment. Decreasing liver enzyme levels during follow-up are possibly reassuring, while the progressive reduction in GFR and the increase in BUN are worrisome and require further study.

Directions in plasma wakefield acceleration.

This introductory article is a synopsis of the status and prospects of particle-beam-driven plasma wakefield acceleration (PWFA). Conceptual and experimental breakthroughs obtained over the last years have initiated a rapid growth of the research field, and increased maturity of underlying technology allows an increasing number of research groups to engage in experimental R&D. We briefly describe the fundamental mechanisms of PWFA, from which its chief attractions arise. Most importantly, this is the capability of extremely rapid acceleration of electrons and positrons at gradients many orders of magnitude larger than in conventional accelerators. This allows the size of accelerator units to be shrunk from the kilometre to metre scale, and possibly the quality of accelerated electron beam output to be improved by orders of magnitude. In turn, such compact and high-quality accelerators are potentially transformative for applications across natural, material and life sciences. This overview provides contextual background for the manuscripts of this issue, resulting from a Theo Murphy meeting held in the summer of 2018. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

FLASHForward: plasma wakefield accelerator science for high-average-power applications.

The FLASHForward experimental facility is a high-performance test-bed for precision plasma wakefield research, aiming to accelerate high-quality electron beams to GeV-levels in a few centimetres of ionized gas. The plasma is created by ionizing gas in a gas cell either by a high-voltage discharge or a high-intensity laser pulse. The electrons to be accelerated will either be injected internally from the plasma background or externally from the FLASH superconducting RF front end. In both cases, the wakefield will be driven by electron beams provided by the FLASH gun and linac modules operating with a 10 Hz macro-pulse structure, generating 1.25 GeV, 1 nC electron bunches at up to 3 MHz micro-pulse repetition rates. At full capacity, this FLASH bunch-train structure corresponds to 30 kW of average power, orders of magnitude higher than drivers available to other state-of-the-art LWFA and PWFA experiments. This high-power functionality means FLASHForward is the only plasma wakefield facility in the world with the immediate capability to develop, explore and benchmark high-average-power plasma wakefield research essential for next-generation facilities. The operational parameters and technical highlights of the experiment are discussed, as well as the scientific goals and high-average-power outlook. This article is part of the Theo Murphy meeting issue 'Directions in particle beam-driven plasma wakefield acceleration'.

Alkaline Phosphatase Replacement Therapy for Hypophosphatasia in Development and Practice.

Hypophosphatasia (HPP) is an inherited disorder that affects bone and tooth mineralization characterized by low serum alkaline phosphatase. HPP is caused by loss-of-function mutations in the ALPL gene encoding the protein, tissue-nonspecific alkaline phosphatase (TNSALP). TNSALP is expressed by mineralizing cells of the skeleton and dentition and is associated with the mineralization process. Generalized reduction of activity of the TNSALP leads to accumulation of its substrates, including inorganic pyrophosphate (PPi) that inhibits physiological mineralization. This leads to defective skeletal mineralization, with manifestations including rickets, osteomalacia, fractures, and bone pain, all of which can result in multi-systemic complications with significant morbidity, as well as mortality in severe cases. Dental manifestations are nearly universal among affected individuals and feature most prominently premature loss of deciduous teeth. Management of HPP has been limited to supportive care until the introduction of a TNSALP enzyme replacement therapy (ERT), asfotase alfa (AA). AA ERT has proven to be transformative, improving survival in severely affected infants and increasing overall quality of life in children and adults with HPP. This chapter provides an overview of TNSALP expression and functions, summarizes HPP clinical types and pathologies, discusses early attempts at therapies for HPP, summarizes development of HPP mouse models, reviews design and validation of AA ERT, and provides up-to-date accounts of AA ERT efficacy in clinical trials and case reports, including therapeutic response, adverse effects, limitations, and potential future directions in therapy.

The impact of repeated mismatches in kidney transplantations performed after nonrenal solid organ transplantation.

The aim of this study was to determine whether kidney transplantations performed after previous nonrenal solid organ transplants are associated with worse graft survival when there are repeated HLA mismatches (RMM) with the previous donor(s). We performed a retrospective cohort study using data from the Scientific Registry of Transplant Recipients. Our cohort comprised 6624 kidney transplantations performed between January 1, 1990 and January 1, 2015. All patients had previously received 1 or more nonrenal solid organ transplants. RMM were observed in 35.3% of kidney transplantations and 3012 grafts were lost over a median follow-up of 5.4 years. In multivariate Cox regression analyses, we found no association between overall graft survival and either RMM in class 1 (hazard ratio [HR]: 0.97, 95% confidence interval [CI] 0.89-1.07) or class 2 (HR: 0.95, 95% CI 0.85-1.06). Results were similar for the associations between RMM, death-censored graft survival, and patient survival. Our results suggest that the presence of RMM with previous donor(s) does not have an important impact on allograft survival in kidney transplant recipients who have previously received a nonrenal solid organ transplant.

On the discovery of cementum.

Though cementum of the tooth root is critical for periodontal structure and tooth attachment and function, this tissue was not discovered and characterized on human teeth until a full century later than enamel and dentin. Early observations from the seventeenth to the nineteenth centuries by Marcello Malpighi, Antonie van Leeuwenhoek, Robert Blake, Jacques Tenon and Georges Cuvier founded a confusing and conflicting nomenclature that obscured the nature of cementum, often conflating it with bone. Advances in microscopy and histological procedures yielded the first detailed descriptions of human cementum in the 1830s by Jan Purkinje and Anders Retzius, who identified for the first time acellular and cellular types of cementum, and the resident cementocytes embedded in the latter. Comparative anatomy studies by Richard Owen and others over the latter half of the nineteenth century identified coronal and radicular cementum varieties across the Reptilia and Mammalia. The functional importance of cementum was not appreciated until detailed anatomical studies of the periodontium were performed by G.V. Black and others in the late nineteenth and early twentieth centuries. These early studies on cementum laid the foundation for more advanced understanding of cementum ultrastructure, composition, development, physiology, disease, genetics, repair and regeneration throughout the twentieth and into the twenty-first century.

Extracellular vesicles in blood, milk and body fluids of the female and male urogenital tract and with special regard to reproduction.

Extracellular vesicles (EVs) are released from almost all cells and tissues. They are able to transport substances (e.g. proteins, RNA or DNA) at higher concentrations than in their environment and may adhere in a receptor-controlled manner to specific cells or tissues in order to release their content into the respective target structure. Blood contains high concentrations of EVs mainly derived from platelets, and, at a smaller amount, from erythrocytes. The female and male reproductive tracts produce EVs which may be associated with fertility or infertility and are released into body fluids and mucosas of the urogenital organs. In this review, the currently relevant detection methods are presented and critically compared. During pregnancy, placenta-derived EVs are dynamically detectable in peripheral blood with changing profiles depending upon progress of pregnancy and different pregnancy-associated pathologies, such as preeclampsia. EVs offer novel non-invasive diagnostic tools which may reflect the situation of the placenta and the foetus. EVs in urine have the potential of reflecting urogenital diseases including cancers of the neighbouring organs. Several methods for detection, quantification and phenotyping of EVs have been established, which include electron microscopy, flow cytometry, ELISA-like methods, Western blotting and analyses based on Brownian motion. This review article summarises the current knowledge about EVs in blood and cord blood, in the different compartments of the male and female reproductive tracts, in trophoblast cells from normal and pre-eclamptic pregnancies, in placenta ex vivo perfusate, in the amniotic fluid, and in breast milk, as well as their potential effects on natural killer cells as possible targets.

High Risk of Graft Failure in Emerging Adult Heart Transplant Recipients.

Emerging adulthood (17-24 years) is a period of high risk for graft failure in kidney transplant. Whether a similar association exists in heart transplant recipients is unknown. We sought to estimate the relative hazards of graft failure at different current ages, compared with patients between 20 and 24 years old. We evaluated 11 473 patients recorded in the Scientific Registry of Transplant Recipients who received a first transplant at <40 years old (1988-2013) and had at least 6 months of graft function. Time-dependent Cox models were used to estimate the association between current age (time-dependent) and failure risk, adjusted for time since transplant and other potential confounders. Failure was defined as death following graft failure or retransplant; observation was censored at death with graft function. There were 2567 failures. Crude age-specific graft failure rates were highest in 21-24 year olds (4.2 per 100 person-years). Compared to individuals with the same time since transplant, 21-24 year olds had significantly higher failure rates than all other age periods except 17-20 years (HR 0.92 [95%CI 0.77, 1.09]) and 25-29 years (0.86 [0.73, 1.03]). Among young first heart transplant recipients, graft failure risks are highest in the period from 17 to 29 years of age.

Impact of HLA mismatch at first kidney transplant on lifetime with graft function in young recipients.

As HLA matching has been progressively de-emphasized in the American deceased donor (DD) kidney allocation algorithm, concerns have been raised that poor matching at first transplant may lead to greater sensitization and more difficulty finding an acceptable donor for a second transplant should the first transplant fail. We compared proportion of total observed lifetime with graft function after first transplant, and waiting times for a second transplant between individuals with different levels of HLA mismatch (MM) at first transplant. We studied patients recorded in the United States Renal Data System (1988-2009) who received a first DD transplant at age ≤21 years (n = 8433), and the subgroup who were listed for a second DD transplant following first graft failure (n = 2498). Compared with recipients of 2-3 MM first grafts, 4-6 MM graft recipients spent 12% less of their time and 0-1 MM recipients 15% more time with a functioning graft after the first transplant (both p < 0.0001); 4-6 MM recipients were significantly less likely (hazard ratio [HR] 0.87 [95% confidence interval 0.76, 0.98]; p = 0.03), and 0-1 MM recipients more likely (HR 1.26 [0.99, 1.60]; p = 0.06) to receive a second transplant after listing. The benefits of better HLA matching at first transplant on lifetime with graft function are significant, but relatively small.

Changes in DXA and quantitative CT measures of musculoskeletal outcomes following pediatric renal transplantation.

This prospective study evaluated changes in dual energy X-ray absorptiometry (DXA) whole body bone mineral content (WB-BMC) and spine areal bone mineral density (spine-BMD), and tibia quantitative computed tomography (QCT) trabecular and cortical volumetric BMD and cortical area in 56 children over 12 months following renal transplantation. At transplant, spine-BMD Z-scores were greater in younger recipients (<13 years), versus 898 reference participants (p < 0.001). In multivariate models, greater decreases in spine-BMD Z-scores were associated with greater glucocorticoid dose (p < 0.001) and declines in parathyroid hormone levels (p = 0.008). Changes in DXA spine-BMD and QCT trabecular BMD were correlated (r = 0.47, p < 0.01). At 12 months, spine-BMD Z-scores remained elevated in younger recipients, but did not differ in older recipients (≥ 13) and reference participants. Baseline WB-BMC Z-scores were significantly lower than reference participants (p = 0.02). Greater glucocorticoid doses were associated with declines in WB-BMC Z-scores (p < 0.001) while greater linear growth was associated with gains in WB-BMC Z-scores (p = 0.01). Changes in WB-BMC Z-scores were associated with changes in tibia cortical area Z-scores (r = 0.52, p < 0.001), but not changes in cortical BMD Z-scores. Despite resolution of muscle deficits, WB-BMC Z-scores at 12 months remained significantly reduced. These data suggest that spine and WB DXA provides insight into trabecular and cortical outcomes following pediatric renal transplantation.

Quality indicators for initial licensure and discipline in nursing laws in South Korea and North Carolina.

BACKGROUND: The Korean regulatory framework of nursing licensure reflects that of the USA, but its content differs in some of the powers related to quality assurance. AIM: This article compares regulatory quality indicators and describes core standards in nursing regulations that are related to both initial licensure and discipline for three groups: the National Council of State Boards of Nursing, the North Carolina and the South of Korea. METHODS: A descriptive, comparative law design is used to examine the differences and similarities in the quality indicators and core standards found in three documents: the National Council of State Boards of Nursing Model Act, the North Carolina Nursing Practice Act and the Korean Medical Service Act for registered nurses. RESULTS: The findings indicate that ten quality indicators and two standards appear in study objects. Although most of the quality indicators are common to all documents, some differences are found in terms of the scope of criminal background checks and the range of grounds for disciplinary action. LIMITATIONS: These findings cannot be generalized in the USA because although the North Carolina nursing act was selected as an example of US nursing laws, nursing laws differ somewhat across states. CONCLUSIONS: This comparative study shows a clear opportunity to develop indicators that acknowledge the important areas of competence and good moral character and how they can improve patient safety in Korea. IMPLICATIONS FOR NURSING AND HEALTH POLICY: This study provides recommendations for Korean nursing legislative redesign and pointers for other jurisdictions to consider.

Murine IRF8 Mutation Offers New Insight into Osteoclast and Root Resorption.

Interferon regulatory factor 8 (IRF8), a transcription factor expressed in immune cells, functions as a negative regulator of osteoclasts and helps maintain dental and skeletal homeostasis. Previously, we reported that a novel mutation in the IRF8 gene increases susceptibility to multiple idiopathic cervical root resorption (MICRR), a form of tooth root resorption mediated by increased osteoclast activity. The IRF8 G388S variant in the highly conserved C-terminal motif is predicted to alter the protein structure, likely impairing IRF8 function. To investigate the molecular basis of MICRR and IRF8 function in osteoclastogenesis, we generated Irf8 knock-in (KI) mice using CRISPR/Cas9 technique modeling the human IRF8G388S mutation. The heterozygous (Het) and homozygous (Homo) Irf8 KI mice showed no gross morphological defects, and the development of hematopoietic cells was unaffected and similar to wild-type (WT) mice. The Irf8 KI Het and Homo mice showed no difference in macrophage gene signatures important for antimicrobial defenses and inflammatory cytokine production. Consistent with the phenotype observed in MICRR patients, Irf8 KI Het and Homo mice demonstrated significantly increased osteoclast formation and resorption activity in vivo and in vitro when compared to WT mice. The oral ligature-inserted Het and Homo mice displayed significantly increased root resorption and osteoclast-mediated alveolar bone loss compared to WT mice. The increased osteoclastogenesis noted in KI mice is due to the inability of IRF8G388S mutation to inhibit NFATc1-dependent transcriptional activation and downstream osteoclast specific transcripts, as well as its impact on autophagy-related pathways of osteoclast differentiation. This translational study delineates the IRF8 domain important for osteoclast function and provides novel insights into the IRF8 mutation associated with MICRR. IRF8G388S mutation mainly affects osteoclastogenesis while sparing immune cell development and function. These insights extend beyond oral health and significantly advance our understanding of skeletal disorders mediated by increased osteoclast activity and IRF8's role in osteoclastogenesis.

Emittance preservation in a plasma-wakefield accelerator.

Radio-frequency particle accelerators are engines of discovery, powering high-energy physics and photon science, but are also large and expensive due to their limited accelerating fields. Plasma-wakefield accelerators (PWFAs) provide orders-of-magnitude stronger fields in the charge-density wave behind a particle bunch travelling in a plasma, promising particle accelerators of greatly reduced size and cost. However, PWFAs can easily degrade the beam quality of the bunches they accelerate. Emittance, which determines how tightly beams can be focused, is a critical beam quality in for instance colliders and free-electron lasers, but is particularly prone to degradation. We demonstrate, for the first time, emittance preservation in a high-gradient and high-efficiency PWFA while simultaneously preserving charge and energy spread. This establishes that PWFAs can accelerate without degradation-an essential step toward energy boosters in photon science and multistage facilities for compact high-energy particle colliders.

Bone Sialoprotein Is Critical for Alveolar Bone Healing in Mice.

Bone sialoprotein (BSP) is an extracellular matrix (ECM) protein associated with mineralized tissues, particularly bone and cementum. BSP includes functional domains implicated in collagen binding, hydroxyapatite nucleation, and cell signaling, although its function(s) in osteoblast and osteoclast differentiation and function remain incompletely understood. Genetic ablation of BSP in Ibsp knockout (Ibsp-/-) mice results in developmental bone mineralization and remodeling defects, with alveolar bone more severely affected than the femurs and tibias of the postcranial skeleton. The role of BSP in alveolar bone healing has not been studied. We hypothesized that BSP ablation would cause defective alveolar bone healing. We employed a maxillary first molar extraction socket healing model in 42-d postnatalIbsp-/- and wild-type (WT) control mice. Tissues were collected at 0, 7, 14, 21, and 56 d postprocedure (dpp) for analysis by micro-computed tomography (microCT), histology, in situ hybridization (ISH), immunohistochemistry (IHC), and quantitative polymerase chain reaction (qPCR) array. As expected, alveolar bone healing progressed in WT mice with increasing bone volume fraction (BV/TV), bone mineral density (BMD), and tissue mineral density (TMD), transitioning from woven to mature bone from 7 to 56 dpp. Ibsp messenger RNA (mRNA) and BSP protein were strongly expressed during alveolar bone healing in parallel with other osteogenic markers. Compared to WT, Ibsp-/- mice exhibited 50% to 70% reduced BV/TV and BMD at all time points, 7% reduced TMD at 21 dpp, abnormally increased Col1a1 and Alpl mRNA expression, and persistent presence of woven bone and increased bone marrow in healing sockets. qPCR revealed substantially dysregulated gene expression in alveolar bone of Ibsp-/- versus WT mice, with significantly disrupted expression of 45% of tested genes in functional groups, including markers for osteoblasts, osteoclasts, mineralization, ECM, cell signaling, and inflammation. We conclude that BSP is a critical and nonredundant factor for alveolar bone healing, and its absence disrupts multiple major pathways involved in appropriate healing.

Wnt/ß-catenin pathway regulates bone morphogenetic protein (BMP2)-mediated differentiation of dental follicle cells.

BACKGROUND AND OBJECTIVE: Bone morphogenetic protein 2 (BMP2)-induced osteogenic differentiation has been shown to occur through the canonical Wnt/ßcatenin pathway, whereas factors promoting canonical Wnt signaling in cementoblasts inhibit cell differentiation and promote cell proliferation in vitro. The aim of this study was to investigate whether putative precursor cells of cementoblasts, dental follicle cells (murine SVF4 cells), when stimulated with BMP2, would exhibit changes in genes/proteins associated with the Wnt/ß-catenin pathway. MATERIAL AND METHODS: SVF4 cells were stimulated with BMP2, and the following assays were carried out: (i) Wnt/ß-catenin pathway activation assessed by western blotting, ß-catenin/transcription factor (TCF) reporter assays and expression of the lymphoid enhancer-binding factor-1 (Lef1), transcription factor 7 (Tcf7), Wnt inhibitor factor 1 (Wif1) and Axin2 (Axin2) genes; and (ii) cementoblast/osteoblast differentiation assessed by mineralization in vitro, and by the mRNA levels of runt-related transcription factor 2 (Runx2), osterix (Osx), alkaline phosphatase (Alp), osteocalcin (Ocn) and bone sialoprotein (Bsp), determined by quantitative PCR after treatment with wingless-type MMTV integration site family, member 3A (WNT3A) and knockdown of ß-catenin. RESULTS: WNT3A induced ß-catenin nuclear translocation and up-regulated the transcriptional activity of a canonical Wnt-responsive reporter, suggesting that the Wnt/ß-catenin pathway functions in SVF4 cells. Activation of Wnt signaling with WNT3A suppressed BMP2-mediated induction of cementoblast/osteoblast maturation of SVF4 cells. However, ß-catenin knockdown showed that the BMP2-induced expression of cementoblast/osteoblast differentiation markers requires endogenous ß-catenin. WNT3A down-regulated transcripts for Runx2, Alp and Ocn in SVF4 cells compared with untreated cells. In contrast, BMP2 induction of Bsp transcripts occurred independently of Wnt/ß-catenin signaling. CONCLUSION: These data suggest that stabilization of ß-catenin by WNT3A inhibits BMP2-mediated induction of cementoblast/osteoblast differentiation in SVF4 cells, although BMP2 requires endogenous Wnt/ß-catenin signaling to promote cell maturation.

The effects of a community-based partnership, Project Access Dallas (PAD), on emergency department utilization and costs among the uninsured.

BACKGROUND: Approximately 19% of non-elderly adults are without health insurance. The uninsured frequently lack a source of primary care and are more likely to use the emergency department (ED) for routine care. Improving access to primary care for the uninsured is one strategy to reduce ED overutilization and related costs. METHODS: A comparison group quasi-experimental design was used to evaluate a broad-based community partnership that provided access to care for the uninsured-Project Access Dallas (PAD)-on ED utilization and related costs. Eligible uninsured patients seen in the ED were enrolled in PAD (n = 265) with similar patients not enrolled in PAD (n = 309) serving as controls. Study patients were aged 18-65 years, <200% of the federal poverty level and uninsured. Outcome measures include the number of ED visits, hospital days and direct and indirect costs. RESULTS: PAD program enrollees had significantly fewer ED visits (0.93 vs. 1.44; P < 0.01) and fewer inpatient hospital days (0.37 vs. 1.07; P < 0.05) than controls. Direct hospital costs were ∼60% less ($1188 vs. $446; P < 0.01) and indirect costs were 50% less ($313 vs. $692; P < 0.01). CONCLUSIONS: A broad-based community partnership program can significantly reduce ED utilization and related costs among the uninsured.