Consecutive dosing of UVB irradiation induces loss of ABCB5 expression and activation of EMT and fibrosis proteins in limbal epithelial cells similar to pterygium epithelium.

Pterygium pathogenesis is often attributed to a population of altered limbal stem cells, which initiate corneal invasion and drive the hyperproliferation and fibrosis associated with the disease. These cells are thought to undergo epithelial to mesenchymal transition (EMT) and to contribute to subepithelial stromal fibrosis. In this study, the presence of the novel limbal stem cell marker ABCB5 in clusters of basal epithelial pterygium cells co-expressing with P63α and P40 is reported. ABCB5-positive pterygium cells also express EMT-associated fibrosis markers including vimentin and α-SMA while their ß-catenin expression is reduced. By using a novel in vitro model of two-dose UV-induced EMT activation on limbal epithelial cells, we could observe the dysregulation of EMT-related proteins including an increase of vimentin and α-SMA as well as downregulation of ß-catenin in epithelial cells correlating to downregulation of ABCB5. The sequential irradiation of limbal fibroblasts also induced an increase in vimentin and α-SMA. Taken together, these data demonstrate for the first time the expression of ABCB5 in pterygium stem cell activity and EMT-related events while the involvement of limbal stem cells in pterygium pathogenesis is exhibited via sequential irradiation of limbal epithelial cells. The later in vitro approach can be used to further study the involvement of limbal epithelium UV-induced EMT in pterygium pathogenesis and help identify novel treatments against pterygium growth and recurrence.

Knowledge diffusion in the network of international business travel.

We use aggregated and anonymized information based on international expenditures through corporate payment cards to map the network of global business travel. We combine this network with information on the industrial composition and export baskets of national economies. The business travel network helps to predict which economic activities will grow in a country, which new activities will develop and which old activities will be abandoned. In statistical terms, business travel has the most substantial impact among a range of bilateral relationships between countries, such as trade, foreign direct investments and migration. Moreover, our analysis suggests that this impact is causal: business travel from countries specializing in a specific industry causes growth in that economic activity in the destination country. Our interpretation of this is that business travel helps to diffuse knowledge, and we use our estimates to assess which countries contribute or benefit the most from the diffusion of knowledge through global business travel.

The value of complementary co-workers.

As individuals specialize in specific knowledge areas, a society's know-how becomes distributed across different workers. To use this distributed know-how, workers must be coordinated into teams that, collectively, can cover a wide range of expertise. This paper studies the interdependencies among co-workers that result from this process in a population-wide dataset covering educational specializations of millions of workers and their co-workers in Sweden over a 10-year period. The analysis shows that the value of what a person knows depends on whom that person works with. Whereas having co-workers with qualifications similar to one's own is costly, having co-workers with complementary qualifications is beneficial. This co-worker complementarity increases over a worker's career and offers a unifying framework to explain seemingly disparate observations, answering questions such as "Why do returns to education differ so widely?" "Why do workers earn higher wages in large establishments?" "Why are wages so high in large cities?"

UV light-blocking contact lenses protect against short-term UVB-induced limbal stem cell niche damage and inflammation.

UVB irradiation has been linked to pathogenesis of pterygium, a conjunctival tumor growing onto transparent cornea, the windscreen of the eye. Due to corneal anatomy, ambient UVB irradiation is amplified at the stem cell-containing nasal limbus. The aim of this study was to analyse the effect of a UV-blocking contact lens (UVBCL, senofilcon A, Class 1 UV blocker) on limbal epithelial cells and fibroblasts under UVB irradiation compared to a non-UVB-blocking contact lens. UVBCL prevented UVB-induced DNA damage (as assessed by cyclobutane pyrimidine dimer immunostaining) as well as a decrease in proliferation and scratch wound closure rate of both limbal epithelial and fibroblast cells. Similarly, UVBCL protected limbal epithelial cells from UVB-induced loss of their phenotype in terms of colony forming efficiency and stem cell marker expression (ABCB5, P63α, integrin ß1) compared to controls. Moreover, with UVBCL pro-inflammatory cytokines such as TNFα and MCP1 remained unchanged. These data demonstrate the significance of UV-protection in preserving the limbal niche in response to at least short-term UVB. Our data support the use of UVBCL in protecting limbal niche cells, especially after limbal stem cell transplantation and in patients after pterygium surgery, to help prevent recurrences.

Blood coagulation dissected.

Hemostasis is the physiological control of bleeding and is initiated by subendothelial exposure. Platelets form the primary vascular seal in three stages (localization, stimulation and aggregation), which are triggered by specific interactions between platelet surface receptors and constituents of the subendothelial matrix. As a secondary hemostatic plug, fibrin clot formation is initiated and feedback-amplified to advance the seal and stabilize platelet aggregates comprising the primary plug. Once blood leakage has been halted, the fibrinolytic pathway is initiated to dissolve the clot and restore normal blood flow. Constitutive and induced anticoagulant and antifibrinolytic pathways create a physiological balance between too much and too little clot production. Hemostatic imbalance is a major burden to global healthcare, resulting in thrombosis or hemorrhage.

[Stem cell-based strategies in vascular surgery]. / Stammzell-basierter biologischer Gefäßersatz.

Critical chronic ischemia in patients with underlying arterial occlusive disease requires vascular reconstructive surgery. The limited supply of suitable small-diameter autologous vascular grafts in many patients and obvious disadvantages of synthetic bypass material demand the development of clinically usable tissue-engineered blood vessel substitutes. Despite substantial progress in the field over the last two decades, their implementation into the clinical routine has been challenging. The limited replicative life span of human adult vascular cells and their slow rate of collagenous matrix production in vitro have posed important problems in the development of mechanically robust and biologically functional engineered grafts. With recent advances in stem cell research, new cell sources for vascular tissue engineering have become available. In particular, the discovery of human induced pluripotent stem (iPS) cells derived from adult differentiated cells, as well as of human multipotent adult mesenchymal stem cells without gene modification requirements and related safety concerns, may advance the development of novel autologous cell-based tissue engineering approaches. Here we discuss recent developments in the field of vascular progenitor cells and opportunities and challenges for the clinical translation of stem cell-engineered vascular tissue substitutes.

Detection of ABCB5 tumour antigen-specific CD8+ T cells in melanoma patients and implications for immunotherapy.

ATP binding cassette subfamily B member 5 (ABCB5) has been identified as a tumour-initiating cell marker and is expressed in various malignancies, including melanoma. Moreover, treatment with anti-ABCB5 monoclonal antibodies has been shown to inhibit tumour growth in xenotransplantation models. Therefore, ABCB5 represents a potential target for cancer immunotherapy. However, cellular immune responses against ABCB5 in humans have not been described so far. Here, we investigated whether ABCB5-reactive T cells are present in human melanoma patients and tested the applicability of ABCB5-derived peptides for experimental induction of human T cell responses. Peripheral blood mononuclear cells (PBMNC) isolated from blood samples of melanoma patients (n = 40) were stimulated with ABCB5 peptides, followed by intracellular cytokine staining (ICS) for interferon (IFN)-γ and tumour necrosis factor (TNF)-α. To evaluate immunogenicity of ABCB5 peptides in naive healthy donors, CD8 T cells were co-cultured with ABCB5 antigen-loaded autologous dendritic cells (DC). ABCB5 reactivity in expanded T cells was assessed similarly by ICS. ABCB5-reactive CD8+ T cells were detected ex vivo in 19 of 29 patients, melanoma antigen recognised by T cells (MART-1)-reactive CD8+ T cells in six of 21 patients. In this small, heterogeneous cohort, reactivity against ABCB5 was significantly higher than against MART-1. It occurred significantly more often and independently of clinical characteristics. Reactivity against ABCB5 could be induced in 14 of 16 healthy donors in vitro by repeated stimulation with peptide-loaded autologous DC. As ABCB5-reactive CD8 T cells can be found in the peripheral blood of melanoma patients and an ABCB5-specific response can be induced in vitro in naive donors, ABCB5 could be a new target for immunotherapies in melanoma.

Positional OSA part 2: retrospective cohort analysis with a new classification system (APOC).

BACKGROUND: In Part 1 of this two-part article, the Amsterdam Positional Obstructive Sleep Apnoea Classification (APOC) was recently introduced, a classification system aimed at facilitating the identification of suitable candidates for positional therapy (PT): patients who will benefit from a clinically significant improvement of their obstructive sleep apnoea (OSA) with PT. APOC was developed with new generation PT devices in mind rather than conventional PT (tennis ball technique). New generation PT can be defined as a well-tolerated device which prevents a patient from adopting the worst sleeping position (WSP) without negatively influencing sleep efficiency, as objectified by a full night polysomnography (PSG). PT is rapidly gaining momentum in the scope of OSA treatment. The objective of this manuscript is to measure the prevalence of position-dependent obstructive sleep apnoea (POSA) according to the APOC, in a consecutive series of patients referred for PSG as well as an investigation of associations between POSA and certain patient characteristics. METHODS: We performed a retrospective, single-centre cohort study including a consecutive series of patients who underwent a PSG during the period of April 2010 until October 2010. RESULTS: Within this OSA-cohort (n = 253), a prevalence of POSA of 69 % when applying APOC is measured, compared to 64 % when applying Cartwright's classification. An inverse relation between POSA and BMI was observed, likewise between POSA and apnoea hypopnoea index (AHI). CONCLUSION: We are of opinion that APOC is a suitable tool to identify patients who will or will not benefit from PT, thus resulting in more cost-efficient treatment.

The Co-Expression of Kallikrein 5 and Kallikrein 7 Associates with Poor Survival in Non-HPV Oral Squamous-Cell Carcinoma.

OBJECTIVE: Oral squamous-cell carcinoma (OSCC) still has a poor prognosis. Lymph node metastasis (LNM) is a major determinant of treatment decisions and prognosis. Serine protease inhibitor Kazal-type 5 (SPINK5) is the inhibitor of kallikrein 5 (KLK5) and KLK7. SPINK5, KLK5 and KLK7 are three of the genes of a recently validated LNM-predicting gene expression profile in OSCC. This study evaluates their clinicopathological role and value as biomarkers in OSCC. METHODS: Eighty-three patients with primary OSCC, treated surgically between 1996 and 2000, were included. Gene expression data were acquired from a previously reported study. Human papillomavirus (HPV) status was determined by an algorithm for HPV-16. Protein expression for KLK5, KLK7 and SPINK5 was semi-quantitatively determined in all 83 tumours by immunohistochemistry. All expression data were correlated with clinicopathological parameters. RESULTS: Concurrent loss of KLK5 and KLK7 correlates with worse disease-specific and overall survival (DSS and OS). Multivariate analysis proved that co-expression is an independent prognostic factor for DSS (p = 0.029) and OS (p = 0.001). CONCLUSION: This report demonstrates that concurrent loss of KLK5 and KLK7 associates with a poor clinical outcome in OSCC and could therefore serve as prognostic marker in this disease.

Positional OSA part 1: Towards a clinical classification system for position-dependent obstructive sleep apnoea.

BACKGROUND: In 1984, Cartwright suggested that physicians should differentiate between patients with either positional obstructive sleep apnoea (POSA) or non-positional OSA. Treatment of POSA has advanced dramatically recently with the introduction of a new generation of positional therapy (PT), a small device attached to either the neck or chest which corrects the patient from adopting the supine position through a vibrating stimulus. Encouraging data have been published suggesting that this simple therapy successfully prevents patients with POSA from adopting the supine position without negatively influencing sleep efficiency, as well as allowing for good adherence. Unfortunately, evaluating the efficacy of PT and comparing results are hindered by the fact that there are no universally used POSA criteria. In 1984, Cartwright introduced the arbitrary cut-off point of a difference of 50% or more in apnoea index between supine and non-supine positions. INTRODUCTION: The aim of this project was to introduce a new classification system, which ideally should identify suitable candidates for PT: patients that will benefit from a clinically significant improvement of their OSA with PT. The shared use of this classification can facilitate collection of data across multiple centres and comparison of results across studies. We report on the development and process that resulted in the Amsterdam Positional OSA Classification (APOC). METHOD: A panel of three field experts were instructed to independently assign the diagnosis POSA to 100 randomly selected patients they considered likely to benefit from a clinically significant improvement of their OSA with PT. In a group setting, the completed lists were compared. Discrepancies were discussed until consensus was met. This resulted in the consensus standard used to calibrate the new classification. Using the nominal group technique, the APOC was developed. RESULTS: The APOC criteria evolve around the percentage of total sleep time spent in either the worst sleeping position (WSP) or the best sleeping position (BSP) and the apnoea-hypopnoea index (AHI) in BSP. On applying APOC, one discriminates between the true positional patient, the non-positional patient and the multifactorial patient, whose OSA severity is influenced in part by sleep position. APOC has an increased sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) compared to previously applied POSA criteria in identifying patients that will benefit from positional therapy.

Evaluating the test re-test reliability and inter-subject variability of Health Care Provider manual fluid resuscitation performance.

BACKGROUND: Health Care Providers (HCPs) report that manual techniques of intravascular fluid resuscitation are commonly used during pediatric shock management. The optimal pediatric fluid resuscitation technique is currently unknown. We sought to determine HCP test-retest reliability (repeatability) and inter-subject variability of fluid resuscitation performance outcomes to inform the design of future studies. METHODS: Fifteen consenting HCPs from McMaster Children's Hospital, in Hamilton, Canada participated in this single-arm interventional trial. Participants were oriented to a non-clinical model representing a 15 kg toddler, which incorporated a 22-gauge IV catheter. Following a standardization procedure, participants administered 600 mL (40 mL/kg) of saline to the simulated child under emergency conditions using prefilled 60-mL syringes. Each participant completed 5 testing trials. All testing was video recorded, with fluid administration time outcome data (in seconds) extracted from trial videos by two blinded outcome assessors. Data describing catheter dislodgement events, volume of saline effectively delivered, and participant demographics were also collected. The primary outcome of fluid administration time test-retest reliability was analyzed by one-way analysis of variance (ANOVA) and intra-class correlation (ICC), with good reliability defined as ICC > 0.70. RESULTS: Differences in HCP fluid administration times are attributable to inter-subject variability rather than intra-subject variability based on one-way ANOVA analysis, F (14,60) = 43.125; p < 0.001. Test-retest reliability of subjects was excellent with ICC = 0.97 (95% CI: 0.95-0.99); p < 0.001. CONCLUSIONS: Findings demonstrate excellent test-retest reliability of HCP fluid resuscitation performance in a setting involving a non-clinical model. Investigators can justify a single evaluation of HCP performance in future studies.

X-ray spectroscopic study of solvent effects on the ferrous and ferric hexacyanide anions.

We present an Fe Kα resonant inelastic X-ray scattering (RIXS) and X-ray emission (XES) study of ferrous and ferric hexacyanide dissolved in water and ethylene glycol. We observe that transitions below the absorption edge show that the solvent has a distinct effect on the valence electronic structure. In addition, both the RIXS and XES spectra show a stabilization of the 2p levels when dissolved in water. Using molecular dynamics simulations, we propose that this effect arises from the hydrogen-bonding interactions between the complex and nearby solvent molecules. This withdraws electron density from the ligands, stabilizing the complex but also causing a slight increase in π-backbonding.

Reversal of new, factor-specific oral anticoagulants by rFVIIa, prothrombin complex concentrate and activated prothrombin complex concentrate: a review of animal and human studies.

INTRODUCTION: Recombinant activated factor VII (rFVIIa), prothrombin complex concentrate (PCC) and activated PCC (aPCC) are three non-specific haemostatic agents sometimes employed to reverse new, factor-specific oral anticoagulants. METHODS: We conducted a review in the literature to compare the abilities of rFVIIa, PCC and aPCC to reverse factor-specific anticoagulants. MEDLINE and EMBASE databases were searched up to Oct 2013. RESULTS: Eleven animal studies and two human trials met predefined inclusion criteria. To account for dosing variations of anticoagulants among studies, data were interpreted based on standards referenced from human trials at therapeutic doses. In animal studies, inconsistencies in the reversal abilities of rFVIIa, PCC and aPCC can be partly attributed to inter-species differences in the affinity among various clotting factors and tissue factors. Moreover, the differences in the affinity between species-specific clotting factors and anticoagulants that were initially designed to inhibit human factor may impose additional obstacles when comparing single factor rFVIIa with agents that contained multiple clotting factors. In the absence of a common clinical indication for the utilization of rFVIIa, PCC and aPCC, it is difficult, if not impossible, to establish an equivalent dose among these haemostatic agents when comparing their effectiveness in reversing factor-specific oral anticoagulants. Human trials were too few and sub-optimally designed to draw definite conclusions. CONCLUSION: While preclinical studies may hint at a role for these haemostatic agents in reversing the anticoagulant effects of oral, factor-specific anticoagulants, existing trials offer inconclusive evidence to guide a clinical decision among individual agents with respect to potency and thrombosis risk. The mechanistic differences of these hemostatic agents in terms of their interactions with other coagulation factors impose major obstacles for the scientists using animal models to compare the efficacy of these reversal agents.

Photooxidation and photoaquation of iron hexacyanide in aqueous solution: A picosecond X-ray absorption study.

We present a picosecond Fe K-edge absorption study of photoexcited ferrous and ferric hexacyanide in water under 355 and 266 nm excitation. Following 355 nm excitation, the transient spectra for the ferrous and ferric complexes exhibit a red shift of the edge reflecting an increased electron density at the Fe atom. For the former, an enhanced pre-edge transition is also observed. These observations are attributed to the aquated [Fe(CN)5OH2](3-) species, based on quantum chemical calculations which also provide structural parameters. Upon 266 nm excitation of the ferric complex, a transient reminiscent of the aquated species is observed (appearance of a pre-edge feature and red shift of the edge) but it is different from that obtained under 355 nm excitation. This points to a new reaction channel occurring through an intermediate state lying between these two excitation energies. Finally, 266 nm excitation of the ferrous species is dominated by the photooxidation channel with formation of the ferric complex as main photoproduct. However, we observe an additional minor photoproduct, which is identical to the 266 nm generated photoproduct of the ferric species, suggesting that under our experimental conditions, the pump pulse photooxidises the ferrous complex and re-excites the primary ferric photoproduct.

Solvent-induced luminescence quenching: static and time-resolved X-ray absorption spectroscopy of a copper(I) phenanthroline complex.

We present a static and picosecond X-ray absorption study at the Cu K-edge of bis(2,9-dimethyl-1,10-phenanthroline)copper(I) ([Cu(dmp)2](+); dmp = 2,9-dimethyl-1,10-phenanthroline) dissolved in acetonitrile and dichloromethane. The steady-state photoluminescence spectra in dichloromethane and acetonitrile are also presented and show a shift to longer wavelengths for the latter, which points to a stronger stabilization of the excited complex. The fine structure features of the static and transient X-ray spectra allow an unambiguous assignment of the electronic and geometric structure of the molecule in both its ground and excited (3)MLCT states. Importantly, the transient spectra are remarkably similar for both solvents, and the spectral changes can be rationalized using the optimized ground- and excited-state structures of the complex. The proposed assignment of the lifetime shortening of the excited state in donor solvents (acetonitrile) to a metal-centered exciplex is not corroborated here. Molecular dynamics simulations confirm the lack of complexation; however, in both solvents the molecules come close to the metal but undergo rapid exchange with the bulk. The shortening of the lifetime of the title complex and nine additional related complexes can be rationalized by the decrease in the (3)MLCT energy. Deviations from this trend may be explained by means of the effects of the dihedral angle between the ligand planes, the solvent, and the (3)MLCT-(1)MLCT energy gap.

Markers of circulating tumour cells in the peripheral blood of patients with melanoma correlate with disease recurrence and progression.

BACKGROUND: Multimarker quantitative real-time polymerase chain reaction (qRT-PCR) represents an effective method for detecting circulating tumour cells in the peripheral blood of patients with melanoma. OBJECTIVES: To investigate whether the phenotype of circulating melanoma cells represents a useful indicator of disease stage, recurrence and treatment efficacy. METHODS: Peripheral blood was collected from 230 patients with melanoma and 152 healthy controls over a period of 3years and 9months. Clinical data and blood samples were collected from patients with primary melanoma (early stages, 0-II, n=154) and metastatic melanoma (late stages, III-IV, n=76). Each specimen was examined by qRT-PCR analysis for the expression of five markers: MLANA, ABCB5, TGFß2, PAX3d and MCAM. RESULTS: In total, 212 of the patients with melanoma (92%) expressed markers in their peripheral blood. Two markers, MLANA and ABCB5, had the greatest prognostic value, and were identified as statistically significant among patients who experienced disease recurrence within our study period, being expressed in 45% (MLANA) and 49% (ABCB5) of patients with recurrence (P=0·001 and P=0·031, respectively). For patients administered nonsurgical treatments, MCAM expression correlated with poor treatment outcome. CONCLUSIONS: Circulating tumour cells were detectable at all stages of disease and long after surgical treatment, even when patients were considered disease free. Specifically, expression of ABCB5 and MLANA had significant prognostic value in inferring disease recurrence, while MCAM expression was associated with poor patient outcome after treatment, confirming multimarker qRT-PCR as a potential technique for monitoring disease status.

[Spontaneous dental abscesses in familial hypophosphatemic rickets]. / Multipele spontane odontogene abcessen bij familiaire hypofosfatemische rachitis.

Symptoms of familial hypophosphatemic rickets are growth retardation, the formation of O- or X-legs, pain of the joints, spontaneous dental abscesses, and delayed tooth eruption. The dental symptoms are predominantly attributable to the demineralization of dentin. In absence of adequate preventive measurements,familial hypophosphatemic rickets may lead to spontaneous pulpal necrosis. The prophylactic application of occlusal sealants might be effective in preventing abscess formation.

[Peri-implantitis in the general oral and maxillofacial surgery practice. A pilot study]. / Peri-implantitis in de algemene kaakchirurgische praktijk. Een pilotonderzoek.

A peri-implant infection is a disorder with an annually increasing prevalence and incidence as a result of the increasing number of oral implants utilized. Based on existing literature, a patient-control study was carried out, as a pilot study, among patients who had been treated with oral implants at a department of oral and maxillofacial surgery in a general hospital. Significant relations were found between on the one hand the prevalence of peri-implantitis and on the other hand bone augmentation, a suprastructure of a fixed partial denture or a complete removable overdenture on a ball attachment mesostructure when compared to a crown, poor oral hygiene, poor periodontal condition, and the absence of keratinized mucosa surrounding the implant.

Design of a hybrid double-sideband/single-sideband (schlieren) objective aperture suitable for electron microscopy.

A novel design is described for an aperture that blocks a half-plane of the electron diffraction pattern out to a desired scattering angle, and then--except for a narrow support beam--transmits all of the scattered electrons beyond that angle. Our proposed tulip-shaped design is thus a hybrid between the single-sideband (ssb) aperture, which blocks a full half-plane of the diffraction pattern, and the conventional (i.e. fully open) double-sideband (dsb) aperture. The benefits of this hybrid design include the fact that such an aperture allows one to obtain high-contrast images of weak-phase objects with the objective lens set to Scherzer defocus. We further demonstrate that such apertures can be fabricated from thin-foil materials by milling with a focused ion beam (FIB), and that such apertures are fully compatible with the requirements of imaging out to a resolution of at least 0.34nm. As is known from earlier work with single-sideband apertures, however, the edge of such an aperture can introduce unwanted, electrostatic phase shifts due to charging. The principal requirement for using such an aperture in a routine data-collection mode is thus to discover appropriate materials, protocols for fabrication and processing and conditions of use such that the hybrid aperture remains free of charging over long periods of time.