Granular metals with SiNxdielectrics.

Understanding and controlling nanoscale interface phenomena, such as band bending and secondary phase formation, is crucial for electronic device optimization. In granular metal (GM) studies, where metal nanoparticles are embedded in an insulating matrix, the importance of interface phenomena is frequently neglected. We demonstrate that GMs can serve as an exemplar system for evaluating the role of secondary phases at interfaces through a combination of x-ray photoemission spectroscopy (XPS) and electrical transport studies. We investigated SiNxas an alternative to more commonly used oxide-insulators, as SiNx-based GMs may enable high temperature applications when paired with refractory metals. Comparing Co-SiNxand Mo-SiNxGMs, we found that, in the tunneling-dominated insulating regime, Mo-SiNxhad reduced metal-silicide formation and orders-of-magnitude lower conductivity. XPS measurements indicate that metal-silicide and metal-nitride formation are mitigatable concerns in Mo-SiNx. Given the metal-oxide formation seen in other GMs, SiNxis an appealing alternative for metals that readily oxidize. Furthermore, SiNxprovides a path to metal-nitride nanostructures, potentially useful for various applications in plasmonics, optics, and sensing.

Expression of the secondary granule proteins major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX) is required for eosinophilopoiesis in mice.

Eosinophil activities are often linked with allergic diseases such as asthma and the pathologies accompanying helminth infection. These activities have been hypothesized to be mediated, in part, by the release of cationic proteins stored in the secondary granules of these granulocytes. The majority of the proteins stored in these secondary granules (by mass) are major basic protein 1 (MBP-1) and eosinophil peroxidase (EPX). Unpredictably, a knockout approach targeting the genes encoding these proteins demonstrated that, unlike in mice containing a single deficiency of only MBP-1 or EPX, the absence of both granule proteins resulted in the near complete loss of peripheral blood eosinophils with no apparent impact on any other hematopoietic lineage. Moreover, the absence of MBP-1 and EPX promoted a concomitant loss of eosinophil lineage-committed progenitors in the marrow, identifying a specific blockade in eosinophilopoiesis as the causative event. Significantly, this blockade of eosinophilopoiesis is also observed in ex vivo cultures of marrow progenitors and is not rescued in vivo by adoptive bone marrow engraftment, suggesting a cell-autonomous defect in marrow progenitors. These observations implicate a role for granule protein gene expression as a regulator of eosinophilopoiesis and provide another strain of mice congenitally deficient of eosinophils.

Human versus mouse eosinophils: "that which we call an eosinophil, by any other name would stain as red".

The respective life histories of human subjects and mice are well defined and describe a unique story of evolutionary conservation extending from sequence identity within the genome to the underpinnings of biochemical, cellular, and physiologic pathways. As a consequence, the hematopoietic lineages of both species are invariantly maintained, each with identifiable eosinophils. This canonical presence nonetheless does not preclude disparities between human and mouse eosinophils, their effector functions, or both. Indeed, many books and reviews dogmatically highlight differences, providing a rationale to discount the use of mouse models of human eosinophilic diseases. We suggest that this perspective is parochial and ignores the wealth of available studies and the consensus of the literature that overwhelming similarities (and not differences) exist between human and mouse eosinophils. The goal of this review is to summarize this literature and in some cases provide experimental details comparing and contrasting eosinophils and eosinophil effector functions in human subjects versus mice. In particular, our review will provide a summation and an easy-to-use reference guide to important studies demonstrating that although differences exist, more often than not, their consequences are unknown and do not necessarily reflect inherent disparities in eosinophil function but instead species-specific variations. The conclusion from this overview is that despite nominal differences, the vast similarities between human and mouse eosinophils provide important insights as to their roles in health and disease and, in turn, demonstrate the unique utility of mouse-based studies with an expectation of valid extrapolation to the understanding and treatment of patients.

The construction of transgenic and gene knockout/knockin mouse models of human disease.

The genetic and physiological similarities between mice and humans have focused considerable attention on rodents as potential models of human health and disease. Together with the wealth of resources, knowledge, and technologies surrounding the mouse as a model system, these similarities have propelled this species to the forefront of biomedical research. The advent of genomic manipulation has quickly led to the creation and use of genetically engineered mice as powerful tools for cutting edge studies of human disease research including the discovery, refinement, and utility of many currently available therapeutic regimes. In particular, the creation of genetically modified mice as models of human disease has remarkably changed our ability to understand the molecular mechanisms and cellular pathways underlying disease states. Moreover, the mouse models resulting from gene transfer technologies have been important components correlating an individual's gene expression profile to the development of disease pathologies. The objective of this review is to provide physician-scientists with an expansive historical and logistical overview of the creation of mouse models of human disease through gene transfer technologies. Our expectation is that this will facilitate on-going disease research studies and may initiate new areas of translational research leading to enhanced patient care.

Identification of Acute Coronary Syndrome in the Elderly.

When older adults experience acute coronary syndrome (ACS), they often present with what are considered "atypical" symptoms. Because their symptoms less often match the expected presentation of ACS, older patients can have delayed time to assessment, to performance of an electrocardiogram, to diagnosis, and to definitive management. Unfortunately, it is this very group of patients who are at the highest risk for having ACS and for complications from ACS. This article aims to outline presentation, outcomes, and potential solutions of underrecognition of ACS in the older adult population.

A novel histologic scoring system to evaluate mucosal biopsies from patients with eosinophilic esophagitis.

BACKGROUND & AIMS: Eosinophilic esophagitis (EoE) is characterized by medically/surgically-resistant gastroesophageal reflux symptoms and dense squamous eosinophilia. Studies suggest that histologic assessment of esophageal eosinophilia alone cannot reliably separate patients with EoE from those with gastroesophageal reflux disease (GERD). Our goal was to develop an assay to identify EoE patients and perhaps differentiate EoE from other causes of esophageal eosinophilia. METHODS: A monoclonal antibody specific for an eosinophil secondary granule protein (eosinophil peroxidase [EPX]) was developed and shown to specifically identify intact eosinophils and detect eosinophil degranulation in formalin-fixed specimens. A histopathologic scoring algorithm was developed to analyze data from patient evaluations; the utility of this algorithm was assessed by using archived esophageal tissues from patients with known diagnoses of EoE and GERD as well as controls from 2 tertiary care centers. RESULTS: Intraobserver/interobserver blinded evaluations demonstrated a significant difference (P < .001) between scores of samples taken from control subjects, from patients with esophageal eosinophilia who had a diagnosis of EoE, and from patients with GERD (P < .001). This algorithm also was able to identify patients whose clinical course was suggestive of a diagnosis of EoE, but that nonetheless failed to reach the critical threshold number of > or =15 eosinophils in a high-power (40x) microscopy field. CONCLUSIONS: A novel immunohistochemical scoring system was developed to address an unmet medical need to differentiate histologic specimens from patients with EoE relative to those with GERD. The availability of a unique anti-EPX-specific monoclonal antibody, combined with the ease/rapidity of this staining method and scoring system, will provide a valuable strategy for the assessment of esophageal eosinophilia.

Alternative housing for Xenopus laevis.

At the authors' facility, housing arrangements for Xenopus laevis were cumbersome and labor-intensive, requiring technicians to wash frog tanks by hand several times a week. The authors describe an alternative housing solution they implemented by modifying a rack system that was originally used to maintain zebrafish. The rack's self-contained water circulation and filtration system saved technicians time and labor, and a commercial chiller attached to the mechanism efficiently controlled frogs' environmental temperature.

Pivotal Advance: eosinophil infiltration of solid tumors is an early and persistent inflammatory host response.

Tumor-associated eosinophilia has been observed in numerous human cancers and several tumor models in animals; however, the details surrounding this eosinophilia remain largely undefined and anecdotal. We used a B16-F10 melanoma cell injection model to demonstrate that eosinophil infiltration of tumors occurred from the earliest palpable stages with significant accumulations only in the necrotic and capsule regions. Furthermore, the presence of diffuse extracellular matrix staining for eosinophil major basic protein was restricted to the necrotic areas of tumors, indicating that eosinophil degranulation was limited to this region. Antibody-mediated depletion of CD4+ T cells and adoptive transfer of eosinophils suggested, respectively, that the accumulation of eosinophils is not associated with T helper cell type 2-dependent immune responses and that recruitment is a dynamic, ongoing process, occurring throughout tumor growth. Ex vivo migration studies have identified what appears to be a novel chemotactic factor(s) released by stressed/dying melanoma cells, suggesting that the accumulation of eosinophils in tumors occurs, in part, through a unique mechanism dependent on a signal(s) released from areas of necrosis. Collectively, these studies demonstrate that the infiltration of tumors by eosinophils is an early and persistent response that is spatial-restricted. It is more important that these data also show that the mechanism(s) that elicit this host response occur, independent of immune surveillance, suggesting that eosinophils are part of an early inflammatory reaction at the site of tumorigenesis.

Grasshoppers in research and education: methods for maintenance and production.

Insects used in research have traditionally been housed and cared for in the investigator's laboratory. Centralized colony maintenance may be advantageous, but presents unique challenges to animal care staff members, who are more familiar with vertebrate research animals. To fill this potential knowledge gap, the authors share the procedures they have developed at Arizona State University for the housing, husbandry, and breeding of grasshoppers used in research and teaching.

Transcatheter Embolization of Type I Endoleaks Associated With Endovascular Abdominal Aortic Aneurysm Repair Using Ethylene Vinyl Alcohol Copolymer.

PURPOSE: To evaluate the feasibility, safety, and outcome of transcatheter embolization using ethylene vinyl alcohol copolymer (EVOH) of type I endoleaks associated with endovascular abdominal aortic aneurysm repair. PATIENT POPULATION AND METHODS: Retrospective chart review was performed to identify 8 consecutive patients who had undergone EVOH embolization for type I endoleaks between 2012 and 2015. The primary approach used to access the endoleak was the perigraft technique, where the endoleak itself is catheterized at the anastomotic site. RESULTS: Six type Ia and 2 type Ib endoleaks were treated. In 2 patients, a direct transabdominal approach was used to access the endoleak because it was inaccessible via the perigraft approach. Coils were used in addition to EVOH in 5 cases. Residual endoleak was noted in 1 case, whereas 2 patients developed a recurrent type I endoleak during follow-up. No EVOH complications were observed. The 5 remaining patients demonstrated freedom from endoleak and reintervention at a mean follow-up of 6.9 months. CONCLUSION: Type I endoleaks can be safely and effectively treated by embolotherapy with EVOH. Larger endoleaks resulting from grossly undersized endografts appear to be unsuitable for EVOH embolization.

A percutaneous swine model of myocardial infarction.

INTRODUCTION: The aim of this study was to develop a percutaneous, low risk, and reproducible technique of MI that simulates human disease. METHODS: MI was induced in 44 swine (32.8+/-7.2 kg) by percutaneous embolization coil deployment in the left anterior descending coronary artery. Hemodynamic measurements, left heart catheterization, and echocardiography were performed pre, post, and 30 days after MI. 3D NOGA viability mapping was performed at baseline and 30 days. Excised hearts were examined histologically. RESULTS: Pre-MI mortality was 6.8% and 24 h mortality was 13.6%. All pigs that survived 24 h after MI remained alive at 30 days. The mean left ventricular ejection fraction decreased from 58.4% to 42.1% (p<0.001) at 30 days. The average thrombolysis in myocardial infarction score was 3, 0, and 1.5 at baseline, post-MI, and 30 days, respectively. At 30 days, the end diastolic diameter, end diastolic volume, end systolic volume, and wall motion index increased from 3.76 to 3.89 cm, 32.5 to 50.0 ml, 14.9 to 27.0 ml, and 1.01 to 1.38, respectively (all p<0.05), while the ejection fraction decreased from 56.5% to 49.4% (p<0.01). Additionally, at 30 days, statistically significant reductions in both unipolar and bipolar voltage in the mid and apical regions of the left ventricle were observed. Postmortem pathology showed a transmural scar in the apical anteroseptal regions with fibrosis in the MI region, which accounted for 14.8% and 14.2% of the total left and right ventricular myocardial area and volume, respectively. DISCUSSION: This model of MI is reliable, reproducible, has a pathophysiology similar to humans, and a lower mortality and ventricular fibrillation rates compared to other models. This model may be used to evaluate the effects of pharmacologics, gene therapy, and stem cell transplantation for the treatment of cardiovascular disease as well as studying mechanisms of cardiac remodeling.

Lateral Lumbar Interbody Fusion in Ambulatory Surgery Centers: Patient Selection and Outcome Measures Compared With an Inhospital Cohort.

STUDY DESIGN: Comparative analysis. OBJECTIVE: To evaluate the safety and outcomes of moving lateral lumbar interbody fusion (LLIF) surgeries to an outpatient setting. SUMMARY OF BACKGROUND DATA: LLIF has been popularized as a less invasive lumbar fusion surgery as an alternative approach to anterior lumbar interbody fusions, posterior lateral interbody fusion, and transforaminal lateral interbody fusion (TLIF). Lumbar fusions have been traditionally performed in a hospital setting because of the potential blood loss, length of surgery, and need for longer recovery. There is a movement to transition spine surgeries to outpatient settings with many benefits afforded by less invasive techniques and technologies. METHODS: The medical records of 70 consecutive patients with prospectively collected data were retrospectively reviewed. Two cohort groups, inpatients (40 patients) and outpatients (30 patients), were created. Patient demographics, risk factors, and body mass index (BMI) were evaluated to determine inclusion criteria for study. RESULT: A total of 34 males and 36 females, age range (31-71) average 59.3 ±â€Š2.3 years. Average BMI was 29.6 ±â€Š1.1 kg/m. The most common level operated on being L3-L4 in both groups (63%). Mean preoperative inpatient Oswestry Disability Index (ODI) increased from 48.5 ±â€Š3.0 to 55.5 ±â€Š3.2 compared with outpatient preoperative ODI means reduced from 45.2 ±â€Š5.1 to 39.1 ±â€Š4.6. There was no statistically significant change in VAS scores between groups. There was however significant improvement in outpatient preoperative VAS scores from 7.3 ±â€Š0.5 to 4.1 ±â€Š0.5, P = 0.045. CONCLUSION: The outcomes of the present study have shown that patients who had LLIF performed in the outpatient setting had statistically significant improvement in ODI scores compared with the inpatient setting (P = 0.013). Fusion was achieved in all patients and there was no evidence of implant failure or subsidence. Complications were transient in both settings. We conclude that outpatient LLIF improves patients' outcomes with similar safety profile as the hospital setting. LEVEL OF EVIDENCE: 3.

Percutaneous transvenous cellular cardiomyoplasty. A novel nonsurgical approach for myocardial cell transplantation.

OBJECTIVES: The study evaluated a nonsurgical means of intramyocardial cell introduction using the coronary venous system for direct myocardial access and cell delivery. BACKGROUND: Direct myocardial cell repopulation has been proposed as a potential method to treat heart failure. METHODS: We harvested bone marrow from Yorkshire swine (n = 6; 50 to 60 kg), selected culture-flask adherent cells, labeled them with the gene for green fluorescence protein, expanded them in culture, and resuspended them in a collagen hydrogel. Working through the coronary sinus, a specialized catheter system was easily delivered to the anterior interventricular coronary vein. The composite catheter system (TransAccess) incorporates a phased-array ultrasound tip for guidance and a sheathed, extendable nitinol needle for transvascular myocardial access. A microinfusion (IntraLume) catheter was advanced through the needle, deep into remote myocardium, and the autologous cell-hydrogel suspension was injected into normal heart. Animals were sacrificed at days 0 (n = 2), 14 (n = 1, + 1 control/collagen biogel only), and 28 (n = 2), and the hearts were excised and examined. RESULTS: We gained widespread intramyocardial access to the anterior, lateral, septal, apical, and inferior walls from the anterior interventicular coronary vein. No death, cardiac tamponade, ventricular arrhythmia, or other procedural complications occurred. Gross inspection demonstrated no evidence of myocardial perforation, and biogel/black tissue dye was well localized to sites corresponding to fluoroscopic landmarks for delivery. Histologic analysis demonstrated needle and microcatheter tracts and accurate cell-biogel delivery. CONCLUSIONS: Percutaneous intramyocardial access is safe and feasible by a transvenous approach through the coronary venous system. The swine offers an opportunity to refine approaches used for cellular cardiomyoplasty.

Decreased size and survival of weanling mice in litters of IL-5-/ -mice are a consequence of the IL-5 deficiency in nursing dams.

We have observed decreased size and increased mortality rates in interleukin 5 (IL-5)-deficient mice versus IL-5-heterozygous and wild-type mice and have sought to define these differences. IL-5-deficient mice nursed by IL-5 deficient mothers were notably underweight, with a high percentage of preweaning mortality. In contrast, IL-5-deficient mice nursed by IL-5-sufficient foster mothers from birth were well-developed and robust at weaning, with a relatively low percentage of preweaning mortality. Mammary tissues from IL-5-deficient females at various landmark stages throughout life were prepared for microscopic assessment. When compared with mammary tissue from normal mice, that from IL-5-deficient dams appeared to have fewer terminal end buds, less well-developed branching of the mammary ducts, and lower overall density of mammary gland structures. The molecular and cellular bases for the differences in mammary gland development in IL-5-deficient mice relative to wild-type animals remains unknown. Under consideration are the roles that IL-5 and eosinophil granulocytes (the primary cell responsive to IL-5) may have in mammary gland development.

Potential nosocomial exposure to Mycobacterium tuberculosis from a bronchoscope.

OBJECTIVE: To investigate a possible nosocomial outbreak of tuberculosis (TB). DESIGN: Retrospective cohort study. SETTING: Community hospital. METHODS: We reviewed medical records, hospital infection control measures, and potential locations of nosocomial exposure. We examined the results of acid-fast bacilli (AFB) smears, cultures, and drug susceptibility testing, and performed a DNA fingerprint analysis. We observed laboratory specimen processing procedures and bronchoscope disinfection procedures. We also reviewed bronchoscopy records. RESULTS: In October 2000, three patients had bronchoscopy specimen cultures that were positive for Mycobacterium tuberculosis. Of the three, only one had clinical signs and symptoms consistent with TB and positive AFB sputum smears. The other two did not have signs and symptoms consistent with TB and had no known exposure to individuals with infectious TB. The three M. tuberculosis isolates had matching DNA fingerprints. No evidence of laboratory cross-contamination was identified. The three culture-positive specimens of M. tuberculosis were collected with the same bronchoscope within 9 days. This bronchoscope was inadequately cleaned and disinfected between patients, and the automated reprocessor used was not approved for use with the hospital bronchoscope. CONCLUSIONS: One of the bronchoscopes at this hospital was contaminated with M. tuberculosis during bronchoscopy of an AFB-smear-positive patient. Subsequent specimen contamination likely occurred because the bronchoscope had been inadequately cleaned and disinfected. Patients who subsequently underwent bronchoscopy were also potentially exposed to M. tuberculosis from this bronchoscope.

Dressing for success: choosing garbing standards for the laboratory animal facility.

The animal research literature devotes much attention to the function of clothing and personal protective equipment in preventing transmission of zoonotic diseases from animal to human, but has said comparatively little about the potential for transmission of disease from human to animal. The authors consider appropriate garbing standards for personnel charged with various tasks within the animal facility, emphasizing the protection of animals from potential health threats.

Allergic pulmonary inflammation promotes the recruitment of circulating tumor cells to the lung.

Allergen-induced respiratory inflammation facilitates and/or elicits the extravasation of proinflammatory leukocytes by well-understood mechanisms that mediate the movement of multiple cell types. The nonspecific character of these pathways led us to hypothesize that circulating cancer cells use similar mechanisms, promoting secondary tumor formation at distal sites. To test this hypothesis, the frequency of metastasis to the lung as a function of allergic pulmonary inflammation was assessed following the i.v. injection of B16-F10 melanoma cells in mice. These studies showed that allergen-induced pulmonary inflammation resulted in a >3-fold increase in lung metastases. This increase was dependent on CD4(+) T-cell activities; however, it occurred independent of the induced eosinophilia associated with allergen provocation. Interventional strategies showed that existing therapeutic modalities for asthma, such as inhaled corticosteroids, were sufficient to block the enhanced pulmonary recruitment of cancer cells from circulation. Additional mechanistic studies further suggested that the ability of circulating cancer cells to extravasate to surrounding lung tissues was linked to the activation of the vascular endothelium via one or more Galpha(i)-coupled receptors. Interestingly, a survey of a clinical breast cancer surgical database showed that the incidence of asthma was higher among patients with lung metastases. Thus, our data show that allergic respiratory inflammation may represent a risk factor for the development of lung metastases and suggest that amelioration of the pulmonary inflammation associated with asthma will have a direct and immediate benefit to the 7% to 8% of breast cancer patients with this lung disease.

When is a mouse basophil not a basophil?

The identification and characterization of mouse basophils have historically been hampered by the extreme rarity of this cell type. Virtually no photomicrographs of hematologically stained (eg, Wright-Giemsa) examples of mouse basophils exist in the literature. However, 4 recent studies in the past 2 years have used flow cytometry and a defined set of cell-surface markers to identify and subsequently isolate mouse "basophils," including the publication of stained cytospin preparations of these cells. Surprisingly, a reevaluation of the data from all 4 of the studies revealed several issues of concern that suggest that the cells under study are not necessarily basophils. Nonetheless, we propose that these studies do provide the foundation for a reevaluation of the defining characteristics of a basophil and/or provide support for the provocative conclusion that a new previously overlooked leukocyte subtype has been identified. The purpose of this commentary is to revisit these previously published studies, highlight the relevant issues, and provide a different perspective in the hope of developing a consensus within the research community as to the true identity of the "basophils" described in these studies.

Coexpression of IL-5 and eotaxin-2 in mice creates an eosinophil-dependent model of respiratory inflammation with characteristics of severe asthma.

Mouse models of allergen provocation and/or transgenic gene expression have provided significant insights regarding the cellular, molecular, and immune responses linked to the pathologies occurring as a result of allergic respiratory inflammation. Nonetheless, the inability to replicate the eosinophil activities occurring in patients with asthma has limited their usefulness to understand the larger role(s) of eosinophils in disease pathologies. These limitations have led us to develop an allergen-naive double transgenic mouse model that expresses IL-5 systemically from mature T cells and eotaxin-2 locally from lung epithelial cells. We show that these mice develop several pulmonary pathologies representative of severe asthma, including structural remodeling events such as epithelial desquamation and mucus hypersecretion leading to airway obstruction, subepithelial fibrosis, airway smooth muscle hyperplasia, and pathophysiological changes exemplified by exacerbated methacholine-induced airway hyperresponsiveness. More importantly, and similar to human patients, the pulmonary pathologies observed are accompanied by extensive eosinophil degranulation. Genetic ablation of all eosinophils from this double transgenic model abolished the induced pulmonary pathologies, demonstrating that these pathologies are a consequence of one or more eosinophil effector functions.

Galphai2-mediated signaling events in the endothelium are involved in controlling leukocyte extravasation.

The trafficking of leukocytes from the blood to sites of inflammation is the cumulative result of receptor-ligand-mediated signaling events associated with the leukocytes themselves as well as with the underlying vascular endothelium. Our data show that Galpha(i) signaling pathways in the vascular endothelium regulate a critical step required for leukocyte diapedesis. In vivo studies using knockout mice demonstrated that a signaling event in a non-lymphohematopoietic compartment of the lung prevented the recruitment of proinflammatory leukocytes. Intravital microscopy showed that blockade was at the capillary endothelial surface and ex vivo studies of leukocyte trafficking demonstrated that a Galpha(i)-signaling event in endothelial cells was required for transmigration. Collectively, these data suggest that specific Galpha(i2)-mediated signaling between endothelial cells and leukocytes is required for the extravasation of leukocytes and for tissue-specific accumulation.