Nasopharyngeal metatranscriptomics reveals host-pathogen signatures of pediatric sinusitis

Acute sinusitis (AS) is the fifth leading cause of antibiotic prescriptions in children. Distinguishing bacterial AS from common viral upper respiratory infections in children is crucial to prevent unnecessary antibiotic use but is challenging with current diagnostic methods. Despite its speed and cost, untargeted RNA sequencing of clinical samples from children with suspected AS has the potential to overcome several limitations of other methods. However, the utility of sequencing-based approaches in analysis of AS has not been fully explored. Here, we performed RNA-seq of nasopharyngeal samples from 221 children with clinically diagnosed AS to characterize their pathogen and host-response profiles. Results from RNA-seq were compared with those obtained using culture for three common bacterial pathogens and qRT-PCR for 12 respiratory viruses. Metatranscriptomic pathogen detection showed high concordance with culture or qRT-PCR, showing 87%/81% sensitivity (sens) / specificity (spec) for detecting bacteria, and 86%/92% (sens/spec) for viruses, respectively. We also detected an additional 22 pathogens not tested for in the clinical panel, and identified plausible pathogens in 11/19 (58%) of cases where no organism was detected by culture or qRT-PCR. We assembled genomes of 205 viruses across the samples including novel strains of coronaviruses, respiratory syncytial virus (RSV), and enterovirus D68. By analyzing host gene expression, we identified host-response signatures that distinguished bacterial and viral infections and correlated with pathogen abundance. Ultimately, our study demonstrates the potential of untargeted metatranscriptomics for in depth analysis of the etiology of AS, comprehensive host-response profiling, and using these together to work towards optimized patient care.

Infective Endocarditis After Transcatheter Versus Surgical Aortic Valve Replacement

BACKGROUND

Scarce data are available comparing infective endocarditis (IE) following surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR). This study aimed to compare the clinical presentation, microbiological profile, management, and outcomes of IE after SAVR versus TAVR.

METHODS

Data were collected from the "Infectious Endocarditis after TAVR International" (enrollment from 2005 to 2020) and the "International Collaboration on Endocarditis" (enrollment from 2000 to 2012) registries. Only patients with an IE affecting the aortic valve prosthesis were included. A 1:1 paired matching approach was used to compare patients with TAVR and SAVR.

RESULTS

A total of 1688 patients were included. Of them, 602 (35.7%) had a surgical bioprosthesis (SB), 666 (39.5%) a mechanical prosthesis, 70 (4.2%) a homograft, and 350 (20.7%) a transcatheter heart valve. In the SAVR versus TAVR matched population, the rate of new moderate or severe aortic regurgitation was higher in the SB group (43.4% vs 13.5%; P < .001), and fewer vegetations were diagnosed in the SB group (62.5% vs 82%; P < .001). Patients with an SB had a higher rate of perivalvular extension (47.9% vs 27%; P < .001) and Staphylococcus aureus was less common in this group (13.4% vs 22%; P = .033). Despite a higher rate of surgery in patients with SB (44.4% vs 27.3%; P < .001), 1-year mortality was similar (SB: 46.5%; TAVR: 44.8%; log-rank P = .697).

CONCLUSIONS

Clinical presentation, type of causative microorganism, and treatment differed between patients with an IE located on SB compared with TAVR. Despite these differences, both groups exhibited high and similar mortality at 1-year follow-up.

Oral hygiene and infective endocarditis: a case control study

OBJECTIVE

To determine if oral hygiene is associated with infective endocarditis (IE) among those at moderate risk for IE.

STUDY DESIGN

This is a case control study of oral hygiene among hospitalized patients with IE (cases) and outpatients with heart valve disease but without IE (controls). The primary outcome was the mean dental calculus index. Secondary outcomes included other measures of oral hygiene and periodontal disease (e.g., dental plaque, gingivitis) and categorization of blood culture bacterial species in case participants.

RESULTS

The 62 case participants had 53% greater mean dental calculus index than the 119 control participants (0.84, 0.55, respectively; difference = 0.29, 95% CI: 0.11, 0.48; P = .002) and 26% greater mean dental plaque index (0.88, 0.70, respectively; difference = 0.18, 95% CI: 0.01.0.36; P = .043). Overall, cases reported fewer dentist and dental hygiene visits (P = .013) and fewer dental visits in the 12 weeks before enrollment than controls (P = .007). Common oral bacteria were identified from blood cultures in 27 of 62 cases (44%).

CONCLUSIONS

These data provide evidence to support and strengthen current American Heart Association guidance that those at risk for IE can reduce potential sources of IE-related bacteremia by maintaining optimal oral health through regular professional dental care and oral hygiene procedures.

Epidemiological Changes and Improvement in Outcomes of Infective Endocarditis in Europe in the Twenty-First Century: An International Collaboration on Endocarditis (ICE) Prospective Cohort Study (2000-2012)

INTRODUCTION

Infective endocarditis (IE) has undergone important changes in its epidemiology worldwide.

METHODS

The study aimed to compare IE epidemiological features and outcomes according to predefined European regions and between two different time periods in the twenty-first century.

RESULTS

IE cases from 13 European countries were included. Two periods were considered: 2000-2006 and 2008-2012. Two European regions were considered, according to the United Nations geoscheme for Europe: Southern (SE) and Northern-Central Europe (NCE). Comparisons were performed between regions and periods. A total of 4195 episodes of IE were included, 2113 from SE and 2082 from NCE; 2787 cases were included between 2000 and 2006 and 1408 between 2008 and 2012. Median (IQR) age was 63.7 (49-74) years and 69.4% were males. Native valve IE (NVE), prosthetic valve IE (PVE), and device-related IE were diagnosed in 68.3%, 23.9%, and 7.8% of cases, respectively; 52% underwent surgery and 19.3% died during hospitalization. NVE was more prevalent in NCE, whereas device-related IE was more frequent in SE. Higher age, acute presentation, hemodialysis, cancer, and diabetes mellitus all were more prevalent in the second period. NVE decreased and PVE and device-related IE both increased in the second period. Surgical treatment also increased from 48.7% to 58.4% (p < 0.01). In-hospital and 6-month mortality rates were comparable between regions and significantly decreased in the second period.

CONCLUSIONS

Despite an increased complexity of IE cases, prognosis improved in recent years with a significant decrease in 6-month mortality. Outcome did not differ according to the European region (SE versus NCE).

Examining General Vaccine Acceptance and COVID-19 Vaccine Intention: Comparison across Pharmacies in California and Ohio

Given the complexities surrounding vaccine acceptance of COVID-19 and other vaccines, it is important to determine the underlying health beliefs of patients in order to bridge gaps and promote vaccine confidence. With pharmacies as key hubs for vaccinations and vaccine conversations, examining patient perspectives through the lens of community pharmacy may provide a targeted insight into their patient populations. The primary objectives of this study were to measure COVID-19 vaccine intention and compare vaccine acceptance at pharmacies and clinics between California and Ohio. The secondary objectives included subgroup comparisons of vaccine intention and vaccine acceptance based on demographic characteristics. A previously validated survey instrument (5C survey tool) was administered at pharmacy sites in California and Ohio to examine respondents' vaccine acceptance (confidence, complacency, constrains, calculation, and collective responsibility). Additional items were added to capture flu and COVID-19 vaccine intention. Reliability and confirmatory factor analysis were completed for the 13-item 5C. Comparisons were made between sites and within different demographic groups. Good reliability (Cronbach's alpha = 0.768) was found, with nearly all items loading on their hypothesized domains. Respondents from Ohio had significantly higher complacency and constraints domain scores. Highest acceptance was revealed in females, individuals with a Master's degree or higher, and individuals with the intention to receive a flu vaccine. The adapted 5C is a reasonable tool to measure vaccine intention in English-speaking populations in the US. Certain demographic groups may have lower vaccine acceptance; pharmacists could consider implementing a tool, such as the 5C tool, to identify low acceptance. Given that the 5C tool gathers information on different domains of vaccine acceptance, healthcare professionals could utilize these results to improve trust and vaccine confidence in their patient populations; focused conversations concerning any of the respective domains could best address individual concerns and barriers about vaccinations, notably the COVID-19 and flu vaccines.

Severe Monkeypox in Hospitalized Patients - United States, August 10-October 10, 2022

As of October 21, 2022, a total of 27,884 monkeypox cases (confirmed and probable) have been reported in the United States.§ Gay, bisexual, and other men who have sex with men have constituted a majority of cases, and persons with HIV infection and those from racial and ethnic minority groups have been disproportionately affected (1,2). During previous monkeypox outbreaks, severe manifestations of disease and poor outcomes have been reported among persons with HIV infection, particularly those with AIDS (3-5). This report summarizes findings from CDC clinical consultations provided for 57 patients aged ≥18 years who were hospitalized with severe manifestations of monkeypox¶ during August 10-October 10, 2022, and highlights three clinically representative cases. Overall, 47 (82%) patients had HIV infection, four (9%) of whom were receiving antiretroviral therapy (ART) before monkeypox diagnosis. Most patients were male (95%) and 68% were non-Hispanic Black (Black). Overall, 17 (30%) patients received intensive care unit (ICU)-level care, and 12 (21%) have died. As of this report, monkeypox was a cause of death or contributing factor in five of these deaths; six deaths remain under investigation to determine whether monkeypox was a causal or contributing factor; and in one death, monkeypox was not a cause or contributing factor.** Health care providers and public health professionals should be aware that severe morbidity and mortality associated with monkeypox have been observed during the current outbreak in the United States (6,7), particularly among highly immunocompromised persons. Providers should test all sexually active patients with suspected monkeypox for HIV at the time of monkeypox testing unless a patient is already known to have HIV infection. Providers should consider early commencement and extended duration of monkeypox-directed therapy†† in highly immunocompromised patients with suspected or laboratory-diagnosed monkeypox.§§ Engaging all persons with HIV in sustained care remains a critical public health priority.

COVID ‐19 Behavioral Questionnaire ( CoBQ ): Comparing the pandemic’s impact on health behavior in three US states

Background

The COVID‐19 pandemic impacted daily routines for a majority of the population, with implications for their health behaviors. Racial and ethnic minorities have been disproportionately impacted by COVID‐19. The novel COVID‐19 Behavioral Questionnaire (CoBQ) was developed in Fall 2020 to provide a means to measure the impact of the COVID‐19 pandemic on the United States population. The study utilized behavioral domains to determine which demographic groups reported that they were made the most vulnerable during Fall‐Winter 2020–2021 of the pandemic.

Objectives

The study aimed to further validate and test the CoBQ in varied US regions and compare the scores obtained from three states, California, Ohio, and Illinois.

Methods

A prospective, multi‐site survey‐based study was designed to further validate and test the 17‐item CoBQ in varied populations. Respondents included patients on routine visits at each pharmacy or clinical site who agreed to complete the survey online via Qualtrics. Data analyses included descriptive statistics, psychometric testing, and comparison of groups using Analysis of Variance.

Results

Completed surveys (n = 507) between October 2021 and March 2021 were analyzed. Respondents were mostly female, white, and had some college education. The CoBQ showed improved reliability compared with previous testing and strong construct validity through factor analysis. Overall scores were similar between three states. The most impacted groups included those who reported within the 18–49 age group, a yearly household income <$50 000, or education up to high school.

Conclusions

The CoBQ is the first validated tool to measure the negative impact of the COVID‐19 pandemic on health behaviors. Results could serve as a baseline to address the most vulnerable patient groups and support identified behavioral needs during a similar pandemic situation.

Local and systemic responses to SARS-CoV-2 infection in children and adults

It is not fully understood why COVID-19 is typically milder in children1-3. Here, to examine the differences between children and adults in their response to SARS-CoV-2 infection, we analysed paediatric and adult patients with COVID-19 as well as healthy control individuals (total n = 93) using single-cell multi-omic profiling of matched nasal, tracheal, bronchial and blood samples. In the airways of healthy paediatric individuals, we observed cells that were already in an interferon-activated state, which after SARS-CoV-2 infection was further induced especially in airway immune cells. We postulate that higher paediatric innate interferon responses restrict viral replication and disease progression. The systemic response in children was characterized by increases in naive lymphocytes and a depletion of natural killer cells, whereas, in adults, cytotoxic T cells and interferon-stimulated subpopulations were significantly increased. We provide evidence that dendritic cells initiate interferon signalling in early infection, and identify epithelial cell states associated with COVID-19 and age. Our matching nasal and blood data show a strong interferon response in the airways with the induction of systemic interferon-stimulated populations, which were substantially reduced in paediatric patients. Together, we provide several mechanisms that explain the milder clinical syndrome observed in children.

Comparative safety profile of chloral hydrate versus other sedatives for procedural sedation in hospitalized infants

BACKGROUND

Given the limited available evidence on chloral hydrate safety in neonatal populations and the discrepancy in chloral hydrate acceptance between the US and other countries, we sought to clarify the safety profile of chloral hydrate compared to other sedatives in hospitalized infants.

METHODS

We included all infants <120 days of life who underwent a minor procedure and were administered chloral hydrate, clonidine, clonazepam, dexmedetomidine, diazepam, ketamine, lorazepam, midazolam, propofol, or pentobarbital on the day of the procedure. We characterized the distribution of infant characteristics and evaluated the relationship between drug administration and any adverse event. We performed propensity score matching, regression adjustment (RA), and inverse probability weighting (IPW) to ensure comparison of similar infants and to account for confounding by indication and residual bias. Results were assessed for robustness to analytical technique by reanalyzing the main outcomes with multivariate logistic regression, a doubly robust IPW with RA model, and a doubly robust augmented IPW model with bias-correction.

RESULTS

Of 650 infants, 497 (76%) received chloral hydrate, 79 (12%) received midazolam, 54 (8%) received lorazepam, and 15 (2%) received pentobarbital. Adverse events occurred in 41 (6%) infants. Using propensity score matching, chloral hydrate was associated with a decreased risk of an adverse event compared to other sedatives, risk difference (95% confidence interval) of -12.79 (-18.61, -6.98), p <  0.001. All other statistical methods resulted in similar findings.

CONCLUSION

Administration of chloral hydrate to hospitalized infants undergoing minor procedures is associated with a lower risk for adverse events compared to other sedatives.

Magnetostriction in Amorphous Co66Fe34 Microcantilevers Fabricated with Hydrogenated Amorphous Silicon

To study the magnetostriction of Co66Fe34 thin films, amorphous silicon microcantilevers were prepared by surface micromachining, and the 136 nm-thick magnetostrictive film was deposited by electron beam physical vapor deposition and patterned on top of the microcantilever structure. The magnetostriction of the Co66Fe34 films was confirmed by measuring the deflection of the cantilevers under a varying magnetic field, reaching displacements up to 8 nm. The configuration was simulated using COMSOL software, yielding a similar deflection behavior as a function of the magnetic field, with a film with a magneto strictive coefficient of λ S ~ 55 p.p.m. The experimental configuration uses a laser and a position sensitive detector to measure the displacement, based on an optical lever configuration, and a piezoelectric stage to calibrate the system.

Spatial and temporal changes in myogenic protein expression by the microenvironment after freeze injury

Skeletal muscle has the remarkable capability to regenerate itself following injury. Adult myogenic stem cells (MSCs) are responsible for the repair and regeneration, and their activity is controlled by intrinsic and extrinsic factors. The aim of this study was to examine and compare the expression levels of Pax3, Pax7, MRF and p38 proteins during the course of regeneration and in different areas of the focal freeze-lesion damaged adult rat TA muscle. Using the focal freeze injury model, immunohistochemistry, laser-capture micro-dissection and Western blot analysis were performed. The results show that (1) in the severely damaged area, the focal freeze-lesion injury significantly activated Pax7 and myogenin expression within 7 days and down-regulated Pax3, MyoD and Myf-5 within 1 or 3 days, and (2) the level of the p38 protein was strongly and transiently up-regulated in the whole muscle on day 7 following injury, whereas the level of the pp38 protein was down-regulated within 3 days in the severely damaged and non-damaged areas. These findings indicate that the temporal (e.g. the time course of regeneration) and spatial (e.g. three zones created by the focal freeze-lesion) cues in a regenerating muscle have a significant impact on the activity of the adult MSCs.

Platelet Aggregation on Extracellular Matrix: Effect of a Recombinant GPIb-Binding Fragment of von Willebrand Factor

Platelets in whole blood incubated on extracellular matrix (ECM) produced by bovine corneal endothelial cells under oscillatory flow conditions demonstrate extensive aggregate formation. Since both platelet-subendothelium and platelet-platelet interactions are mediated by von Willebrand factor (vWF), we used this system to examine the effect of a recombinant GPIb-binding fragment of vWF (designated RG12986), comprising residues 445-733 of the native vWF subunit, on platelet reactivity with ECM. The seven cysteines present in the RG12986 fragment were reduced and alkylated in order to achieve a monomeric conformation. The recombinant vWF fragment binds to unstimulated platelets in the absence of exogenous modulators. When added to platelet-rich plasma, it inhibits ristocetin-induced platelet agglutination. Binding of 51Cr-labeled platelets in reconstituted whole blood to ECM was inhibited by RG12986 in a dose dependent and saturable manner, with IC50 of 4 μM and maximal inhibition (about 70%) at 6 μM. Scanning electron microscope (SEM) analysis showed that addition of RG12986 to whole blood significantly inhibited platelet aggregation on ECM. The extent of inhibition observed with RG12986 at a final concentration of 4 μM was similar to that obtained with the cell adhesion peptide RGDS at the concentration of 0.1 mM. The ability of the RG12986 fragment to inhibit platelet aggregation on ECM is in agreement with the concept that blockade of vWF-GPIb interaction may inhibit further events leading to activation of the glycoprotein IIb/IIIa (GPIIb/IIIa) complex and subsequent thrombus formation.

Reports on the 2017 AAAI Spring Symposium Series

The Association for the Advancement of Artificial Intelligence, in cooperation with Stanford University's Department of Computer Science, presented the 2017 Spring Symposium Series, held Monday through Wednesday, March 27–29, 2017 on the campus of Stanford University. The eight symposia held were Artificial Intelligence for the Social Good (SS-17-01); Computational Construction Grammar and Natural Language Understanding (SS-17-02); Computational Context: Why It's Important, What It Means, and Can It Be Computed? (SS-17-03); Designing the User Experience of Machine Learning Systems (SS-17-04); Interactive Multisensory Object Perception for Embodied Agents (SS-17-05); Learning from Observation of Humans (SS-17-06); Science of Intelligence: Computational Principles of Natural and Artificial Intelligence (SS-17-07); and Wellbeing AI: From Machine Learning to Subjectivity Oriented Computing (SS-17-08). This report, compiled from organizers of the symposia, summarizes the research that took place.

Study on the bio-functionalization of memristive nanowires for optimum memristive biosensors

Semiconductor nanowires are emerging as promising building blocks for biosensors enabling direct electrical detection of various biomolecules.

Use and Safety of Erythromycin and Metoclopramide in Hospitalized Infants

OBJECTIVE

Prokinetic medications are used in premature infants to promote motility and decrease time to full enteral feeding. Erythromycin and metoclopramide are the most commonly used prokinetic medications in the neonatal intensive care unit (NICU), but their safety profile is not well defined.

METHODS

We conducted a large retrospective cohort study using data from 348 NICUs managed by the Pediatrix Medical Group. All of the infants exposed to ≥1 dose of erythromycin, metoclopramide, or both, from a cohort of 8,87,910 infants discharged between 1997 and 2012 were included. We collected laboratory and clinical information while infants were exposed to erythromycin or metoclopramide and described the frequency of laboratory abnormalities and clinical adverse events (AEs).

RESULTS

Metoclopramide use increased from 1997 to 2005 and decreased from 2005 to 2012, whereas erythromycin use remained stable. Erythromycin use was most often associated with a diagnosis of feeding problem (40%), whereas metoclopramide was most often associated with a diagnosis of gastroesophageal reflux (59%). The most common laboratory AE during exposure to erythromycin or metoclopramide was hyperkalemia (8.6/1000 infant days on erythromycin and 11.0/1000 infant days on metoclopramide). Incidence of pyloric stenosis was greater with erythromycin than with metoclopramide (10/1095, 0.9% vs 76/19,001, 0.4%; P = 0.01), but odds were not significantly increased after adjusting for covariates (odds ratio 0.52, 95% confidence interval [CI] 0.26-1.02, P = 0.06). More infants experienced an AE while treated with metoclopramide than with erythromycin (odds ratio 1.21, 95% CI 1.03-1.43).

CONCLUSIONS

Metoclopramide was associated with increased risk of AEs compared with erythromycin. Studies are needed to confirm safety and effectiveness of both the drugs in infants.

Vitamin D attenuates cytokine-induced remodeling in human fetal airway smooth muscle cells

Asthma in the pediatric population remains a significant contributor to morbidity and increasing healthcare costs. Vitamin D3 insufficiency and deficiency have been associated with development of asthma. Recent studies in models of adult airway diseases suggest that the bioactive Vitamin D3 metabolite, calcitriol (1,25-dihydroxyvitamin D3 ; 1,25(OH)2 D3 ), modulates responses to inflammation; however, this concept has not been explored in developing airways in the context of pediatric asthma. We used human fetal airway smooth muscle (ASM) cells as a model of the early postnatal airway to explore how calcitriol modulates remodeling induced by pro-inflammatory cytokines. Cells were pre-treated with calcitriol and then exposed to TNFα or TGFβ for up to 72 h. Matrix metalloproteinase (MMP) activity, production of extracellular matrix (ECM), and cell proliferation were assessed. Calcitriol attenuated TNFα enhancement of MMP-9 expression and activity. Additionally, calcitriol attenuated TNFα and TGFβ-induced collagen III expression and deposition, and separately, inhibited proliferation of fetal ASM cells induced by either inflammatory mediator. Analysis of signaling pathways suggested that calcitriol effects in fetal ASM involve ERK signaling, but not other major inflammatory pathways. Overall, our data demonstrate that calcitriol can blunt multiple effects of TNFα and TGFβ in developing airway, and point to a potentially novel approach to alleviating structural changes in inflammatory airway diseases of childhood.

Distal antral gastropexy - a novel technique to prevent recurrence of giant hiatus hernia in selected cases - a cohort study

INTRODUCTION

The recurrence rate of giant hiatus hernias (GHH) following repair is high (30%) and increases with the hernia size and previous revision surgery. The mechanism of recurrence is poorly understood.

METHODS

This is a retrospective cohort study of all consecutive patients who underwent repair of giant hiatus hernia in a tertiary upper GI referral centre from November 2000 to November 2014. Patients who underwent redo surgery were identified and data on intra-operative findings and procedure performed at primary and redo surgery from their operation notes were collected.

RESULTS

A total of 81 patients underwent primary repair of GHH over the 14 year study period. 10 (12.3%) had symptomatic/radiological recurrence of which 4 were found to have the distal stomach herniating into the chest despite having an intact intra-abdominal wrap/gastropexy. To prevent migration of the distal stomach into the chest, distal gastropexy - fixing the antrum to the anterior abdominal wall, was added to 'conventional' gastropexy in 5 subsequent cases, in whom the antrum was in the chest preoperatively. These cases have no evidence of recurrence at the end of 6 months follow up.

CONCLUSION

Securing the antrum of stomach to the anterior abdominal wall may prevent migration of the distal stomach and other infracolic organs into the chest and thus reduce recurrence of some GHH where antrum had been in chest previously.

On-chip sample preparation and analyte quantification using a microfluidic aqueous two-phase extraction coupled with an immunoassay

Immunoassays are fast and sensitive techniques for analyte quantification, and their use in point-of-care devices for medical, environmental, and food safety applications has potential benefits of cost, portability, and multiplexing. However, immunoassays are often affected by matrix interference effects, requiring the use of complex laboratory extraction and concentration procedures in order to achieve the required sensitivity. In this paper we propose an integrated microfluidic device for the simultaneous matrix clean-up, concentration and detection. This device consists of two modules in series, the first performing an aqueous two-phase extraction (ATPE) for matrix extraction and analyte pre-concentration, and the second an immunoassay for quantification. The model analyte was the mycotoxin ochratoxin A (OTA) in a wine matrix. Using this strategy, a limit of detection (LoD) of 0.26 ng mL(-1) was obtained for red wine spiked with OTA, well below the regulatory limit for OTA in wines of 2 ng mL(-1) set by the European Union. Furthermore, the linear response on the logarithmic concentration scale was observed to span 3 orders of magnitude (0.1-100 ng mL(-1)). These results are comparable to those obtained for the quantification of OTA in plain buffer without an integrated ATPE (LoD = 0.15 ng mL(-1)). The proposed method was also found to provide similar results for markedly different matrices, such as red and white wines. This novel approach based on aqueous two-phase systems can help the development of point-of-care devices that can directly deal with real samples in complex matrices without the need for extra extraction processes and equipment.

CXCL12/CXCR4 signaling in the osteoblast regulates the mesenchymal stem cell and osteoclast lineage populations

The chemokine CXCL12 and its receptor CXCR4 play a key role in regulation of hematopoietic stem cells and cell migratory function during morphogenesis. Osteoblasts express both the ligand and the receptor, but little is known about the role of CXCL12-CXCR4 signaling in maintaining skeletal homeostasis. Using Cre-Lox technology to delete CXCR4 in mature osteoblasts in mice, we show here a significant decrease in bone mass and alterations in cancellous bone structure. CXCR4 gene ablation increased the number of colony-forming units (CFU), CFU-positive for alkaline phosphatase (CFU-AP(+)), and mineralizing nodules in bone marrow stromal cell (BMSC) cultures. The adipocyte precursor population decreased in BMSCs harvested from the KO animals. The nonadherent population of BMSCs harvested from the long bone diaphysis of KO animals formed more osteoclasts, a finding that was associated with increased circulatory levels of pyridinoline, a marker of bone resorption. Our data show that osteoblast-specific CXCR4 deletion has profound effects on the mesenchymal stem cell pool and allocation to the osteoblastic and adipocytic cell lineages. They also show that CXCL12/CXCR4 signaling in the mature osteoblast can feedback to regulate the osteoclast precursor pool size and play a multifunctional role in regulating bone formation and resorption.

The effect of the surface functionalization and the electrolyte concentration on the electrical conductance of silica nanochannels

It is known that the conductance of nanochannels as a function of electrolyte concentration deviates from a linearly proportional relationship and approaches a value independent of the concentration as the electrolyte concentration is lowered. Most of the proposed models account for this behavior by considering a constant surface charge density and an ideal electrolyte solution. However, at low electrolyte concentrations, the ideal electrolyte approximation is no longer valid because the ions that result from the atmospheric carbon dioxide dissolution in water dominate the ionic concentration. In this paper, arrays of silica nanochannels were electrically characterized via conductance measurements. The conductance at low salt concentrations is modeled by a variable surface charge model that accounts for all ionic species in solution. This model was used to determine the variable surface charge of the bare silica nanochannels as well as of chemically modified nanochannels. The model correctly predicted the variation of the nanochannel conductance observed after silane (aminopropyldimethylethoxysilane) functionalization and single-strand DNA immobilization. Finally, pH modification of bulk KCl solutions was employed as an alternative method of changing the surface charge of silica nanochannels. Surface charge calculated from conductance measurements performed at different bulk pH values confirmed that the surface charge of the silica nanochannel walls is sensitive to the H(+) concentration.

Early response of bone marrow osteoprogenitors to skeletal unloading and sclerostin antibody

Sclerostin functions as an antagonist to Wnt signaling and inhibits bone-forming activity. We studied the effects of skeletal unloading and treatment with sclerostin antibody (Scl-Ab) on mesenchymal stem cell, osteoprogenitor and osteoclast precursor pools, and their relationship to bone formation and resorption. Male C57BL/6 mice (5-months-old) were hind limb unloaded for 1 week or allowed normal ambulation and treated with Scl-Ab (25 mg/kg, s.c. injections on days 1 and 4) or placebo. Unloading decreased the serum concentration of bone formation marker P1NP (-35 %), number of colony-forming units (CFU) (-38 %), alkaline phosphatase-positive CFUs (CFU-AP+) (-51 %), and calcified nodules (-35 %); and resulted in a fourfold increase in the number of osteoclast precursors. The effects of Scl-Ab treatment on unloaded and normally loaded mice were nearly identical; Scl-Ab increased serum P1NP and the number of CFU, CFU-AP+, and calcified nodules in ex vivo cultures; and increased osteoblast and bone mineralizing surfaces in vivo. Although the marrow-derived osteoclast precursor population increased with Scl-Ab, the bone osteoclast surface did not change, and the serum concentration of osteoclast activity marker TRACP5b decreased. Our data suggest that short-term Scl-Ab treatment can prevent the decrease in osteoprogenitor population associated with skeletal unloading and increase osteoblast surface and bone mineralizing surface in unloaded animals. The anabolic effects of Scl-Ab treatment on bone are preserved during skeletal unloading. These findings suggest that Scl-Ab treatment can both increase bone formation and decrease bone resorption, and provide a new means for prevention and treatment of disuse osteoporosis.

Bone turnover markers in peripheral blood and marrow plasma reflect trabecular bone loss but not endocortical expansion in aging mice

We examined age-related changes in biochemical markers and regulators of osteoblast and osteoclast activity in C57BL/6 mice to assess their utility in explaining age-related changes in bone. Several recently discovered regulators of osteoclasts and osteoblasts were also measured to assess concordance between their systemic levels versus their levels in marrow plasma, to which bone cells are directly exposed. MicroCT of 6-, 12-, and 24-month-old mice indicated an early age-related loss of trabecular bone volume and surface, followed by endocortical bone loss and periosteal expansion. Trabecular bone loss temporally correlated with reductions in biomarkers of bone formation and resorption in both peripheral blood and bone marrow. Endocortical bone loss and periosteal bone gain were not reflected in these protein biomarkers, but were well correlated with increased expression of osteocalcin, rank, tracp5b, and cathepsinK in RNA extracted from cortical bone. While age-related changes in bone turnover markers remained concordant in blood versus marrow, aging led to divergent changes in blood versus marrow for the bone cell regulators RANKL, OPG, sclerostin, DKK1, and serotonin. Bone expression of runx2 and osterix increased progressively with aging and was associated with an increase in the number of osteoprogenitors and osteoclast precursors. In summary, levels of biochemical markers of bone turnover in blood and bone marrow plasma were predictive of an age-related loss of trabecular surfaces in adult C57BL/6 mice, but did not predict gains in cortical surfaces resulting from cortical expansion. Unlike these turnover markers, a panel of bone cell regulatory proteins exhibited divergent age-related changes in marrow versus peripheral blood, suggesting that their circulating levels may not reflect local levels to which osteoclasts and osteoblasts are directly exposed.

Accupouncture for acute management and rehabilitation of traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) can be life threatening depending on the severity of the insult to the brain. It can also cause a range of debilitating sequelae which require cognitive, motor, communication, emotional, or behavioral rehabilitation of varying intensity and duration. A number of studies conducted and published in China have suggested that acupuncture may be beneficial in the acute treatment and rehabilitation of TBI. The aim of this paper was to determine the efficacy and safety of acupuncture in the acute management or rehabilitation (or both) of patients with a TBI, including cognitive, neurological, motor, communication, emotional, or behavioral complications, or a combination of such complications.

METHODS

We searched the Cochrane Injuries Group Specialised Register, Cochrane Central Register of Controlled Trials 2008, Issue 2 (The Cochrane Library), MEDLINE, EMBASE, CINAHL, AMED, PsycINFO and others. We also searched the Chinese Acupuncture Studies Register, the Studies Register of the Cochrane Complementary Medicine Field, NCCAM, and NIH Clinical Studies Database. Three major Mainland Chinese academic literature databases (CNKI, VIP and Wang Fang Data) were also searched using keywords in simplified Chinese. Searches were completed in December 2009. Randomized controlled studies evaluating different variants of acupuncture and involving participants of any age who had suffered a TBI. Included trials compared acupuncture with placebo or sham treatment, or acupuncture plus other treatments compared with the same other treatments.We excluded trials that only compared different variants of acupuncture or compared acupuncture alone against other treatments alone, as they did not yield the net effect of acupuncture. Two review authors identified potential articles from the literature search and extracted data independently using a data extraction form. We performed methodological assessment of included studies using the Cochrane Collaboration's tool for assessing risk of bias. We were unable to perform quantitative data analysis due to insufficient included studies and available data.

RESULTS

Four RCTs, including 294 participants, reported outcomes specified by this review. Three investigated electro-acupuncture for TBI while one investigated acupuncture for acute TBI. The results seem to suggest that acupuncture is efficacious for these indications, however the low methodological quality of these studies renders the results questionable. No adverse effects of acupuncture were reported in any of the studies.

CONCLUSIONS

The low methodological quality of the included studies does not allow us to make conclusive judgments on the efficacy and safety of acupuncture in either the acute treatment and/or rehabilitation of TBI. Its beneficial role for these indications remains uncertain. Further research with high quality trials is required.

Association between valvular surgery and mortality among patients with infective endocarditis complicated by heart failure

CONTEXT

Heart failure (HF) is the most common complication of infective endocarditis. However, clinical characteristics of HF in patients with infective endocarditis, use of surgical therapy, and their associations with patient outcome are not well described.

OBJECTIVES

To determine the clinical, echocardiographic, and microbiological variables associated with HF in patients with definite infective endocarditis and to examine variables independently associated with in-hospital and 1-year mortality for patients with infective endocarditis and HF, including the use and association of surgery with outcome.

DESIGN, SETTING, AND PATIENTS

The International Collaboration on Endocarditis-Prospective Cohort Study, a prospective, multicenter study enrolling 4166 patients with definite native- or prosthetic-valve infective endocarditis from 61 centers in 28 countries between June 2000 and December 2006.

MAIN OUTCOME MEASURES

In-hospital and 1-year mortality.

RESULTS

Of 4075 patients with infective endocarditis and known HF status enrolled, 1359 (33.4% [95% CI, 31.9%-34.8%]) had HF, and 906 (66.7% [95% CI, 64.2%-69.2%]) were classified as having New York Heart Association class III or IV symptom status. Within the subset with HF, 839 (61.7% [95% CI, 59.2%-64.3%]) underwent valvular surgery during the index hospitalization. In-hospital mortality was 29.7% (95% CI, 27.2%-32.1%) for the entire HF cohort, with lower mortality observed in patients undergoing valvular surgery compared with medical therapy alone (20.6% [95% CI, 17.9%-23.4%] vs 44.8% [95% CI, 40.4%-49.0%], respectively; P < .001). One-year mortality was 29.1% (95% CI, 26.0%-32.2%) in patients undergoing valvular surgery vs 58.4% (95% CI, 54.1%-62.6%) in those not undergoing surgery (P < .001). Cox proportional hazards modeling with propensity score adjustment for surgery showed that advanced age, diabetes mellitus, health care-associated infection, causative microorganism (Staphylococcus aureus or fungi), severe HF (New York Heart Association class III or IV), stroke, and paravalvular complications were independently associated with 1-year mortality, whereas valvular surgery during the initial hospitalization was associated with lower mortality.

CONCLUSION

In this cohort of patients with infective endocarditis complicated by HF, severity of HF was strongly associated with surgical therapy and subsequent mortality, whereas valvular surgery was associated with lower in-hospital and 1-year mortality.

Prey species as possible sources of PBDE exposures for peregrine falcons (Falco peregrinus) nesting in major California cities

Our earlier findings indicate that (1) peregrine falcons (Falco peregrinus anatum Bonaparte) nesting in major California cities have among the highest polybrominated diphenyl ether (PBDE) levels in the world (max ∑PBDEs=100 ppm), and (2) Big City peregrines have higher levels and proportions of the higher-brominated congeners (hepta- to deca-BDEs) than do their Coastal counterparts. In this study we classified the prey species (n =185) from the remains of prey (feathers) at 38 peregrine nest sites over 25 years (1974-1998). We grouped the prey species into 15 categories based on diet and found distinctly different prey patterns for Big City vs. Coastal peregrines. Big City peregrines had a higher (almost three times) weight percentage intake of food waste-eating birds (e.g., rock pigeons, Columba livia) than Coastal peregrines. These differing prey patterns suggest diet as a potential source of the unusually high levels and proportions of higher-brominated PBDEs in Big City peregrines. The relative contributions of diet and dust (e.g., preening) exposure to PBDE patterns in Big City peregrines will be explored in future investigations.

Covalent immobilization of DNA and hybridization on microchips by microsecond electric field pulses

Single square voltage pulses were used to enhance by 7 and 9 orders of magnitude the rate of covalent immobilization and hybridization, respectively, of single stranded DNA probes on a chemically functionalized thin film surface (silicon dioxide) using 2 mm size electrodes. These electrodes were scaled down to 20 μm. Photolithography was used to define the electrode voltage line, ground line, and functionalized thin-film area on a plastic substrate (polyimide). At all electrode dimensions, electric field-assisted DNA immobilization and hybridization can be achieved in the microsecond time scale, far faster than the 2 hr or 16 hr needed for immobilization and hybridization, respectively, without the electric field. Pulse conditions optimized with the large-size electrodes (2 mm) were used in the microelectrodes.

Time-of-Flight Measurements in a-Si:H Between Room Temperature and 130° C°

The drift mobility μd and the mobility-lifetime product μτ in undoped a-Si:H have been studied up to 130°C. The electron μde is temperature-activated with Eae = 0.13 to 0.16 eV. The electron (μτ)e increases with temperature T. For hole transport, we observe the transition from dispersive to non-dispersive transport with increasing T. The hole μdh is ∼ 1/100 of μde, and is activated with Eah = 0.34 to 0.48eV. The hole (μτ)h does not change much with T. A computer simulation demonstrates the high sensitivity of μd to the band tail width.

Heterogeneous immunoassays in microfluidic format using fluorescence detection with integrated amorphous silicon photodiodes

Miniaturization of immunoassays through microfluidic technology has the potential to decrease the time and the quantity of reactants required for analysis, together with the potential of achieving multiplexing and portability. A lab-on-chip system incorporating a thin-film amorphous silicon (a-Si:H) photodiode microfabricated on a glass substrate with a thin-film amorphous silicon-carbon alloy directly deposited above the photodiode and acting as a fluorescence filter is integrated with a polydimethylsiloxane-based microfluidic network for the direct detection of antibody-antigen molecular recognition reactions using fluorescence. The model immunoassay used consists of primary antibody adsorption to the microchannel walls followed by its recognition by a secondary antibody labeled with a fluorescent quantum-dot tag. The conditions for the flow-through analysis in the microfluidic format were defined and the total assay time was 30 min. Specific molecular recognition was quantitatively detected. The measurements made with the a-Si:H photodiode are consistent with that obtained with a fluorescence microscope and both show a linear dependence on the antibody concentration in the nanomolar-micromolar range.

Application of Thin-Film Micromachining for Large-Area Substrates

Surface micromachining is used with amorphous silicon, microcrystalline silicon, silicon nitride and aluminum films as structural materials to form bridge and cantilever structures. Low temperature processing (between 110 and 250 °C) allowed fabrication of structures and devices on glass substrates. Two processes involving different materials as the sacrificial layer are presented: silicon nitride and photoresist. The mechanical integrity of the fabricated structures is discussed. As examples of possible device applications of this technology, air-gap thin film transistors and the electrostatic actuation of bridges and cantilevers are presented.

Amorphous Silicon-Carbon alloys Deposited by Electron-Cyclotron Resonance PECVD

Hydrogenated amorphous silicon-carbon alloys are prepared using electron-cyclotron resonance (ECR) plasma-enhanced chemical-vapor deposition. Hydrogen is used as the excitation gas in the resonance chamber while silane and methane (or ethylene) are introduced in the main chamber. A minimum of 95% hydrogen dilution is used. The microwave power is kept constant at 150 W. The effect of the type of carbon source gas, silane to carbon source gas ratio, deposition pressure, substrate temperature and hydrogen dilution on the deposition rate, bandgap and Urbach energy are studied. The photoconductivity and the Urbach energy of the ECR-deposited films are compared to those prepared with glow discharge with the same bandgap.

Performance of Thin-Film Silicon MEMS Resonators in Vacuum

This paper reports on the fabrication and characterization of microelectromechanical bridge resonators on glass substrates using thin-film technology and surface micromachining. All the processing steps are performed at temperatures below 110°C. The microbridges consist of either a single layer of heavily doped n-type amorphous silicon (n+-a-Si:H) or bilayers of aluminum (Al) and intrinsic a-Si:H. The bridge is suspended over a gate electrode with a 1 μm air-gap. Applying a voltage between the bridge and an underlying Al gate electrode electrostatically actuates the microstructures. The resulting deflection is monitored optically. The resonance of the microbridges is measured in air and in vacuum. Resonance frequencies up to 70 MHz and quality factors up to 3000 are obtained at pressures below 1 Torr. The energy dissipation mechanisms of the resonators are discussed.

Thin film micro arrays with immobilized DNA for hybridization analysis

In this work, a procedure to immobilize DNA probes on a microarray patterned on a flexible plastic substrate is developed. The method involves the chemical activation of a thin film surface, the introduction of amine functionality via a silanization step, the coupling of an adequate crosslinker and finally the immobilization of the DNA probe. The response of different thin-film materials and plastic substrates to the immobilization procedure is discussed. The DNA probes immobilized in the patterned pixels were then allowed to hybridize with complementary target DNA labeled with a fluorescent molecule. A prototype array of thin film pixels of SiO2 functionalized by silanization deposited over a polyimide substrate is demonstrated.