Perfused 3D angiogenic sprouting in a high-throughput in vitro platform.

Angiogenic sprouting, the growth of new blood vessels from pre-existing vessels, is orchestrated by cues from within the cellular microenvironment, such as biochemical gradients and perfusion. However, many of these cues are missing in current in vitro models of angiogenic sprouting. We here describe an in vitro platform that integrates both perfusion and the generation of stable biomolecular gradients and demonstrate its potential to study more physiologically relevant angiogenic sprouting and microvascular stabilization. The platform consists of an array of 40 individually addressable microfluidic units that enable the culture of perfused microvessels against a three-dimensional collagen-1 matrix. Upon the introduction of a gradient of pro-angiogenic factors, the endothelial cells differentiated into tip cells that invaded the matrix. Continuous exposure resulted in continuous migration and the formation of lumen by stalk cells. A combination of vascular endothelial growth factor-165 (VEGF-165), phorbol 12-myristate 13-acetate (PMA), and sphingosine-1-phosphate (S1P) was the most optimal cocktail to trigger robust, directional angiogenesis with S1P being crucial for guidance and repetitive sprout formation. Prolonged exposure forces the angiogenic sprouts to anastomose through the collagen to the other channel. This resulted in remodeling of the angiogenic sprouts within the collagen: angiogenic sprouts that anastomosed with the other perfusion channel remained stable, while those who did not retracted and degraded. Furthermore, perfusion with 150 kDa FITC-Dextran revealed that while the angiogenic sprouts were initially leaky, once they fully crossed the collagen lane they became leak tight. This demonstrates that once anastomosis occurred, the sprouts matured and suggests that perfusion can act as an important survival and stabilization factor for the angiogenic microvessels. The robustness of this platform in combination with the possibility to include a more physiological relevant three-dimensional microenvironment makes our platform uniquely suited to study angiogenesis in vitro.

Identifying patients with bacterial infections using a combination of C-reactive protein, procalcitonin, TRAIL, and IP-10 in the emergency department: a prospective observational cohort study.

OBJECTIVES: The aim was to effectively reduce the unnecessary use of broad spectrum antibiotics in the emergency department (ED), patients with bacterial infections need to be identified accurately. We investigated the diagnostic value of a combination of biomarkers for bacterial infections, C-reactive protein (CRP), and procalcitonin (PCT), together with biomarkers for viral infections, tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and interferon-gamma-induced protein-10 (IP-10), in identifying suspected and confirmed bacterial infections in a general ED population with fever. METHODS: This is a sub-study in the HiTEMP cohort. Patients with fever were included during ED triage, and blood samples were obtained. Using both diagnostics and expert panel analysis, all patients were classified as having either suspected or confirmed bacterial infections, or non-bacterial disease. Using multivariable logistic regression analysis, three biomarker models were analysed: model 1, CRP, TRAIL, IP-10; model 2, PCT, TRAIL, IP-10; and model 3, CRP, PCT, TRAIL, IP-10. RESULTS: A total of 315 patients were included, of whom 228 patients had a suspected or confirmed bacterial infection. The areas under the curve for the combined models were the following: model 1, 0.730 (95% CI 0.665-0.795); model 2, 0.748 (95% CI 0.685-0.811); and model 3, 0.767(95% CI 0.704-0.829). CONCLUSIONS: These findings show that a combination of CRP, PCT, TRAIL and IP-10 can identify bacterial infections with higher accuracy than single biomarkers and combinations of a single bacterial biomarkers combined with TRAIL and IP-10.

Procalcitonin-guided antibiotic therapy in patients with fever in a general emergency department population: a multicentre non-inferiority randomized clinical trial (HiTEMP study).

OBJECTIVES: Overuse of broad-spectrum antibiotics in emergency departments (EDs) results in antibiotic resistance. We determined whether procalcitonin (PCT) -guided therapy can be used to reduce antibiotic regimens in EDs by investigating efficacy, safety and accuracy. METHODS: This was a non-inferiority multicentre randomized clinical trial, performed in two Dutch hospitals. Adult patients with fever ≥38.2°C (100.8°F) in triage were randomized between standard diagnostic workup (control group) and PCT-guided therapy, defined as standard workup with the addition of one single PCT measurement. The treatment algorithm encouraged withholding antibiotic regimens with PCT <0.5 µg/L, and starting antibiotic regimens at PCT ≥0.5 µg/L. Exclusion criteria were immunocompromised conditions, pregnancy, moribund patients, patients <72 h after surgery or requiring primary surgical intervention. Primary outcomes were efficacy, defined as number of prescribed antibiotic regimens; safety, defined as combined safety end point consisting of 30 days mortality, intensive-care unit admission, ED return visit within 2 weeks; accuracy, defined as sensitivity, specificity and area-under-the-curve (AUC) of PCT for bacterial infections. Non-inferiority margin for safety outcome was 7.5%. RESULTS: Between August 2014 and January 2017, 551 individuals were included. In the PCT-guided group (n = 275) 200 (73%) patients were prescribed antibiotic regimens, in the control group (n = 276) 212 (77%) patients were prescribed antibiotics (p 0.28). There was no significant difference in combined safety end point between the PCT-guided group, 29 (11%), and control group, 46 (16%) (p 0.16), with a non-inferiority margin of 0.46% (n = 526). AUC for confirmed bacterial infections for PCT was 0.681 (95% CI 0.633-0.730), and for CRP was 0.619 (95% CI 0.569-0.669). CONCLUSIONS: PCT-guided therapy was non-inferior in terms of safety, but did not reduce prescription of antibiotic regimens in an ED population with fever. In this heterogeneous population, the accuracy of PCT in diagnosing bacterial infections was poor. TRIAL REGISTRATION IN NETHERLANDS TRIAL REGISTER: http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4949.

Validated age-specific reference values for CSF total protein levels in children.

OBJECTIVE: To define age-specific reference values for cerebrospinal fluid (CSF) total protein levels for children and validate these values in children with Guillain-Barré syndrome (GBS), acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS). METHODS: Reference values for CSF total protein levels were determined in an extensive cohort of diagnostic samples from children (<18 year) evaluated at Erasmus Medical Center/Sophia Children's Hospital. These reference values were confirmed in children diagnosed with disorders unrelated to raised CSF total protein level and validated in children with GBS, ADEM and MS. RESULTS: The test results of 6145 diagnostic CSF samples from 3623 children were used to define reference values. The reference values based on the upper limit of the 95% CI (i.e. upper limit of normal) were for 6 months-2 years 0.25 g/L, 2-6 years 0.25 g/L, 6-12 years 0.28 g/L, 12-18 years 0.34 g/L. These reference values were confirmed in a subgroup of 378 children diagnosed with disorders that are not typically associated with increased CSF total protein. In addition, the CSF total protein levels in these children in the first 6 months after birth were highly variable (median 0.47 g/L, IQR 0.26-0.65). According to these new reference values, CSF total protein level was elevated in 85% of children with GBS, 66% with ADEM and 23% with MS. CONCLUSION: More accurate age-specific reference values for CSF total protein levels in children were determined. These new reference values are more sensitive than currently used values for diagnosing GBS and ADEM in children.

Evaluation of a new immunoassay for chromogranin A measurement on the Kryptor system.

BACKGROUND: Chromogranin A (CgA) is a biomarker for neuroendocrine tumors (NETs). The aims of this study were to evaluate differences in measurement between the ThermoFisher Brahms CgA Kryptor assay and the CisBio assay and to investigate the influence of patient covariates. Temperature stability of CgA using both assays was determined. DESIGN AND METHODS: 406 patients were analyzed for serum CgA using both assays. We performed a comparison study to determine whether several patient covariates (gender, use of protein pump inhibitors, impaired kidney function, referral department and tumor location) influenced the results. For the stability study, pooled serum samples were aliquoted and stored at different storage temperatures (room temperature, 4 °C and -20 °C) until assayed. In addition, 15 individual samples were evaluated after storage at 4 °C using the Kryptor assay. RESULTS: Differences in measured concentrations between the assays were statistically significant. Passing & Bablok fit showed ln Y(Kryptor)=1.05 ln X(CisBio) - 0.20 with a bias of 1.0% after logarithmic transformation. Patient covariates were not associated. Patients׳ sera showed variable stability for CgA in the Kryptor assay at room temperature and 4 °C, whereas the recovery in the CisBio assay was stable at both temperatures. CONCLUSION: Differences in measured CgA concentration between the assays could not be explained by the investigated patient covariates. Serum should be stored at -20 °C prior to determination using the Kryptor assay.

An added value for the hemoglobin content in reticulocytes (CHr) and the mean corpuscular volume (MCV) in the diagnosis of iron deficiency in postpartum anemic women.

INTRODUCTION: To evaluate the use of reticulocyte hemoglobin content (CHr) and mean corpuscular volume (MCV) to identify truly iron-deficient women with postpartum anemia (PPA), in order to reduce unnecessary iron supplementation. METHODS: Three hundred women with more than 500 mL of blood loss or clinical signs of anemia were divided in a control (Hb ≥ 10.5 g/dL, N = 150) and postpartum anemia group (PPA, Hb < 10.5 g/dL; N = 150). PPA women were given ferrous fumarate for a period of 4 weeks. Efficacy of the treatment was evaluated by comparing Hb, CHr, and MCV at baseline (T(0)) and after 4 weeks (T(4)). Using standard iron deficiency cut off values for MCV (80 fL) and CHr (28 pg) at T(0), we divided the PPA group of both parameters into two subgroups, one suggestive for iron deficiency and one suggestive for noniron deficiency. RESULTS: Irrespective of the parameter or the subdivision, delta Hb concentrations (T(4) -T(0)) showed a similar increase in all PPA subgroups investigated. Both parameters in the PPA subgroups below their respective cut off value showed a significant improvement toward normalization, while the MCV and CHr in the PPA subgroups above their respective cut off value did not show any significant increase. CONCLUSION: Our data suggest that the etiology of the anemia in postpartum anemic women is not always iron deficiency. Using a combination of Hb, MCV and CHr, we increased the stringency to identify truly iron-deficient postpartum anemic women, thereby reducing unnecessary iron supplementation in those women with sufficient iron stores.

Amplification efficiency: linking baseline and bias in the analysis of quantitative PCR data.

Despite the central role of quantitative PCR (qPCR) in the quantification of mRNA transcripts, most analyses of qPCR data are still delegated to the software that comes with the qPCR apparatus. This is especially true for the handling of the fluorescence baseline. This article shows that baseline estimation errors are directly reflected in the observed PCR efficiency values and are thus propagated exponentially in the estimated starting concentrations as well as 'fold-difference' results. Because of the unknown origin and kinetics of the baseline fluorescence, the fluorescence values monitored in the initial cycles of the PCR reaction cannot be used to estimate a useful baseline value. An algorithm that estimates the baseline by reconstructing the log-linear phase downward from the early plateau phase of the PCR reaction was developed and shown to lead to very reproducible PCR efficiency values. PCR efficiency values were determined per sample by fitting a regression line to a subset of data points in the log-linear phase. The variability, as well as the bias, in qPCR results was significantly reduced when the mean of these PCR efficiencies per amplicon was used in the calculation of an estimate of the starting concentration per sample.

Coordinated down-regulation of KCNQ1 and KCNE1 expression contributes to reduction of I(Ks) in canine hypertrophied hearts.

OBJECTIVE: In animal models of hypertrophy, electrical remodeling giving rise to QT prolongation occurs rapidly and is associated with the development of torsade de pointes (TdP) arrhythmias and sudden death. Chronic AV block (CAVB)-induced hypertrophy in dogs has been associated with a reduction in the slow component (I(Ks)) of the delayed rectifier potassium current (I(K)), which contributes to a prolongation of ventricular repolarization, the development of an acquired form of long QT, and the substrate for triggered activity and TdP. The present study was designed to probe the molecular basis for the decrease in I(Ks) by studying the characteristics of KCNE1 and KCNQ1, the putative genes responsible for formation of the channel. METHODS AND RESULTS: Using a combination of Northern blot, competitive multiplex PCR and immunoblot assays, we found that CAVB reduces KCNE1 and KCNQ1 RNA in the canine ventricles by 70 and 80%, respectively. Protein levels of KCNE1 and KCNQ1 were reduced by 60 and 50%, respectively. We also demonstrate at the molecular level the basis for inter-ventricular difference in I(Ks) density previously reported in hearts of normal dogs and show the basis for reduction of this difference in the CAVB dog. CONCLUSIONS: Our results indicate that the CAVB-induced reduction in I(Ks) is due to a down-regulation of KCNE1 and KCNQ1 transcription. The data suggest that electrical remodeling of the cardiac ventricle during hypertrophy involves regulation of the gene expression through modulation of transcriptional and translational regulatory pathways. The reduction in KCNE1 and KCNQ1 expression increases the dependence of ventricular repolarization on the rapid component of I(K) and may potentiate the action of Class III antiarrhythmic agents.

Time course of structural adaptations in chronic AV block dogs: evidence for differential ventricular remodeling.

To determine the nature and time course of biventricular hypertrophy and concomitant electrical and mechanical changes after creation of complete atrioventricular block (CAVB), six adult dogs (22-30 kg) were subjected to serial magnetic resonance imaging (MRI) and electrocardiography. After 6 days of CAVB, left ventricular (LV) mass, ejection fraction (EF), and Q-T time at a paced rhythm of 60 beats/min were already significantly increased. Maximal values were reached within 14-21 days of CAVB: LV mass, from 116 +/- 11 to 143 +/- 12 g; right ventricular (RV) mass, from 40 +/- 3 to 55 +/- 6 g; EF, from 68 +/- 6% to 86 +/- 5%; and Q-T time, from 285 +/- 25 to 330 +/- 35 ms, all P < 0.05. Cardiac output returned to baseline at day 14. End-diastolic wall thickness increased only in the RV, in which angiotensin type 1 (AT1) receptor mRNA expression was significantly greater. The autopsy correlated well with the MRI results (r = 0.98, P< or = 0.01). In conclusion, electrophysiological, mechanical, and structural adaptation processes after bradycardia-induced volume overload develop rapidly and are completed within 3 wk. The degree of hypertrophy was greater in the RV, which was associated with an increase in AT1 receptor mRNA.

Family care of impaired elderly: a role theory approach.

To understand the behaviour of family members who take care of their impaired parents, a role theoretical model is presented. The model defines three dimensions of human behaviour for assessing the behaviour of role-incumbents. These three dimensions are indicated by the questions: What should be done? What is one willing to do? What can be done? This heuristic model is applied to the caring behaviour of adult children towards their impaired parents. Within each dimension a number of variables are specified and for each of them the scattered research findings of many recent studies in this area have been summarized and integrated. It seems justified to consider the model a useful guide for future research on family care of the elderly.