bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Life Stress Activates Glial Cells in the Hippocampus but Attenuates Cytokine Secretion in Response to an Immune Challenge in Rat Pups
Authors: Saavedra Luis Miguel , Fenton Navarro Bertha , Torner Luz
Published: January 2018

Objective: Early life stress (ELS) increases the vulnerability to developing psychopathological disorders in adulthood that are accompanied by brain inflammatory processes. However, it is not known how a combined double hit (stress and immune) at an early age affects the response of the neuroimmune system. Here we investigated the effect of periodic maternal separation (MS) followed by administration of lipopolysaccharide (LPS) on glial cells in the CA3 region and hilus of the hippocampus and on cytokine release on postnatal day (PN) 15. Methods: Male rat pups were subjected to MS (3 h/day, PN1-14). MS and control pups received a single LPS injection (1 mg/kg of body weight) on PN14. They were subjected to an open field test 1 h later. The pups were sacrificed 90 min after LPS injection (PN14) or on PN15 for cytokine or immunohistological analyses, respectively. Results: LPS reduced the locomotion and induced high corticosterone levels in treated pups. MS or LPS reduced microglial density and activated microglial cells in the hippocampal CA3 and hilus regions. Microglial activation was highest in MS-LPS pups. The astrocyte density was mildly reduced by MS or LPS in the CA3 region and hilus, but the reduction was maximal in MS-LPS pups. LPS increased the secretion of plasmatic interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, and of hippocampal IL-1β protein, but these were attenuated in MS-LPS pups. Conclusion: Although MS and LPS activate neuroimmune cells, stress attenuates the hippocampal and peripheral cytokine response to LPS through an as-yet unidentified adaptive mechanism. These results provide information regarding the neurobiology of stress and inflammation.
Association of Statin Dose With Amputation and Survival in Patients With Peripheral Artery Disease
Authors: Arya Shipra , Khakharia Anjali , Binney Zachary O. , DeMartino Randall R. , Brewster Luke P. , Goodney Philip P. , Wilson Peter W.F.
Published: January 2018

Background:

Statin dose guidelines for patients with peripheral artery disease (PAD) are largely based on coronary artery disease and stroke data. The aim of this study is to determine the effect of statin intensity on PAD outcomes of amputation and mortality.

Methods:

Using an observational cohort study design and a validated algorithm, we identified patients with incident PAD (2003–2014) in the national Veterans Affairs data. Highest statin intensity exposure (high-intensity versus low-to-moderate–intensity versus antiplatelet therapy but no statin use) was determined within 1 year of diagnosis of PAD. Outcomes of interest were lower extremity amputations and death. The association of statin intensity with incident amputation and mortality was assessed with Kaplan-Meier plots, Cox proportional hazards modeling, propensity score–matched analysis, and sensitivity and subgroup analyses, as well, to reduce confounding.

Results:

In 155 647 patients with incident PAD, more than a quarter (28%) were not on statins. Use of high-intensity statins was lowest in patients with PAD only (6.4%) in comparison with comorbid coronary/carotid disease (18.4%). Incident amputation and mortality risk declined significantly with any statin use in comparison with the antiplatelet therapy–only group. In adjusted Cox models, the high-intensity statin users were associated with lower amputation risk and mortality in comparison with antiplatelet therapy–only users (hazard ratio, 0.67; 95% confidence interval, 0.61–0.74 and hazard ratio, 0.74; 95% confidence interval, 0.70–0.77, respectively). Low-to-moderate–intensity statins also had significant reductions in the risk of amputation and mortality (hazard ratio amputation, 0.81; 95% confidence interval, 0.75– 0.86; hazard ratio death, 0.83; 95% confidence interval, 0.81–0.86) in comparison with no statins (antiplatelet therapy only), but effect size was significantly weaker than the high-intensity statins (
P
<0.001). The association of high-intensity statins with lower amputation and death risk remained significant and robust in propensity score–matched, sensitivity, and subgroup analyses.

Conclusions:

Statins, especially high-intensity formulations, are underused in patients with PAD. This is the first population-based study to show that high-intensity statin use at the time of PAD diagnosis is associated with a significant reduction in limb loss and mortality in comparison with low-to-moderate–intensity statin users, and patients treated only with antiplatelet medications but not with statins, as well.
The Masculine Vaginal: Working With Queer Men’s Embodiment at the Transgender Edge
Authors: Hansbury Griffin
Published: January 2018

Turning away from the conspicuous phenomena of transgender experience, with an eye toward locating and illuminating the transgender edge in cisgender, this paper explores the relationship between men and the Vaginal, both material and fantasized. Positing the Vaginal as a counterpart to the Phallic allows a delinkage of vaginal psychic and embodied states from the strictly female so that, like the Phallic, they can be accessed by people of all genders and sexes. This concept goes beyond the conceptual to the fleshy, embodied experience of many transgender men, who live in whole, partial, and/or temporary “female” bodies. It can also be applied to the physio-psychic reality of many cisgender men. Included is a discussion of a case in which a gay cisgender male patient experiences and fantasizes his anus as a vagina.
Maternal knowledge of pertussis and Tdap vaccine and the use of a vaccine information statement
Authors: Payakachat Nalin , Hadden Kristie B , Hanner Jeremy , Ragland Denise
Published: January 2018

Objective:

This study explored maternal knowledge of pertussis and Tdap vaccine and the use of a Tdap Vaccine Information Statement (VIS) to improve that knowledge.

Design:

Prospective cohort study.

Setting:

Two outpatient obstetric clinics at a US academic medical centre.

Methods:

An electronic survey was administered to pregnant women who received care at the clinics. The survey included a test of knowledge of pertussis and Tdap vaccine, a health literacy instrument and demographic questions. A chart review was conducted to determine Tdap vaccination status. The knowledge test was administered before and immediately after participants read the VIS. Differences between pre- and post-knowledge test scores were determined using the Wilcoxon signed-rank test. The effects of two different versions of the VIS on participants’ knowledge gained and associated factors were examined using a repeated-measures mixed model with random effects.

Results:

In total, 279 participants were analysed with an average age of 26.4 ± 5.7 years. The average post-test knowledge score was higher than the pre-test score (6.4 vs 4.2, p < .001). Health literacy score ( p < .001), White race/ethnicity ( p = .007) and higher education level ( p < .001) were positively associated with improved knowledge scores. Both VIS versions improved participants’ knowledge scores to a similar degree. However, knowledge scores were not a predictor of Tdap vaccination in our population.

Conclusion:

A Tdap VIS improved maternal knowledge and is an economical and easily accessible educational tool in clinical practice for promoting Tdap vaccine to pregnant women.
Resolving Discrimination Complaints in Employment Arbitration: An Analysis of the Experience in the Securities Industry
Authors: Lamare J. Ryan , Lipsky David B.
Published: January 2018

This article empirically examines whether employment discrimination claims differ from other types of disputes resolved through arbitration. Whether arbitration is appropriate for resolving violations of anti-discrimination statutes at work is a focus of ongoing policy debates. Yet empirical scholarship has rarely considered whether different types of complaints might have distinct characteristics and receive varied outcomes in arbitration. The authors analyze all of the employment arbitration awards for cases filed between 1991 and 2006 in the financial services industry to determine whether differences in the type of allegation affect award outcomes. They also examine the effects of the financial industry’s decision in 1999 to introduce voluntary arbitration for discrimination claims. Results indicate that discrimination claims largely fared worse in arbitration than did other statutory or non-statutory claims but that arbitration systems are capable of meaningful self-reform.
Wood flour reinforced biodegradable PBS/PLA composites
Authors: Saeed U , Nawaz MA , Al-Turaif HA
Published: January 2018

The advanced development of biocomposites made of biodegradable polymers and natural fibers has initiated great interest because the resultant polymer will degrade absolutely and will not emit toxic substances. Among the biodegradable polymers, the poly(butylene succinate) and poly(lactic acid) have diverse commercial applications and the natural fiber such as wood flour is renewable and cheaper alternative to synthetic fiber. The properties of the composite made of poly(butylene succinate)/poly(lactic acid) blend and wood flour are not compatible due to the poor wettability and interfacial adhesion. Therefore, in the study presented, the Fusabond MB 100 D has been used to improve the interfacial bonding between poly(butylene succinate)/poly(lactic acid) blend and the dispersed wood flour. The results reveal that the addition of FB not only increases the tensile strength but also improves the impact strength of poly(butylene succinate)/poly(lactic acid)wood flour composite under high dynamic loading. Moreover, when Fusabond MB 100 D is added as a coupling agent to the poly(butylene succinate)/poly(lactic acid)wood flour composite results of X-ray photo spectroscopy, fracture surface morphology and dynamical mechanical property indicate the interaction between the poly(butylene succinate)/poly(lactic acid) blend with the wood flour.
Civil Citation
Authors: Nadel Melissa R. , Pesta George , Blomberg Thomas , Bales William D. , Greenwald Mark
Published: January 2018

Objectives:

The primary objective of this study is to assess potential variation across Florida’s counties of their implementation of civil citation and the outcomes associated with that implementation.

Methods:

Interrupted time-series analysis is used to determine whether the trends in juvenile arrests and the total delinquent population referred to the juvenile justice system (either through arrests or through civil citation) were significantly affected by the implementation of civil citation in each county.

Results:

There were immediate and gradual diversion effects of the civil citation program in a number of Florida’s counties. As a result, there is evidence of successful implementation with a few cases of net widening.

Conclusions:

While there was variation between counties in their implementation of civil citation, overall, Florida’s civil citation program was found to provide a diversion from arrest rather than a net-widening outcome. The study concludes with the identification of county-specific factors that characterized the local jurisdictions that were able to successfully overcome the major impediments associated with diversion and other reform programs’ implementation fidelity.
Teachers’ Adoption of Inquiry-Based Learning Activities: The Importance of Beliefs About Education, the Self, and the Context
Authors: Voet Michiel , De Wever Bram
Published: January 2018

Even though studies have shown that the impact of professional development on inquiry-based learning (IBL) tends to remain limited when it fails to consider teachers’ beliefs, there is little known about how these beliefs influence teachers’ adoption of IBL. In answer to this issue, the present study offers a framework that explains teachers’ use of IBL through three constitutive dimensions of beliefs systems, covering the constructs of education, the self, and the context. This framework is empirically investigated through a survey study with 536 secondary school history teachers. The resulting data are used to estimate a structural equation model (SEM), which indicates that the framework is able to explain a relatively large portion (38%) of the variance in teachers’ decision to implement IBL. Based on the findings, the implications for professional development and research on teachers’ use of IBL in general, and within history education in particular, are discussed.
Brain perfusion fixation in male pigs using a safer closed system
Authors: Musigazi Gracia U. , De Vleeschauwer Stéphanie , Sciot Raf , Verbeken Eric , Depreitere Bart
Published: January 2018

Tissue fixation methods are well established for rodents, but not for large animals. We present a simple technique for in situ brain perfusion fixation in a male porcine model, using cervical vessels for inflow and outflow and achieving a closed system. Thirty-four pigs, aged 4.7 ± 0.6 months and weighing 60.7 ± 10.9 kg, were anaesthetised and mechanically ventilated. The ipsilateral common carotid artery and external jugular vein were dissected and constituted the inflow and outflow access, respectively. The brains were perfused and fixed in situ with heparinised saline followed by buffered formaldehyde. Then, specimens (brain, cerebellum and brainstem) were extracted and processed for histology. Fixative fluid leakage was avoided, achieving a closed system. This technique minimises the exposure to toxic chemicals such as formaldehyde and associated hazards (inherent toxicity, eye irritation), thereby increasing operators’ safety. Perfusion was performed with a peristaltic pump for 20–30 minutes at an optimum rate of 0.20 l/min and required only 5 litres of the fixative. The specimens were sufficiently hardened to be extracted. High-quality tissues were available for histology analysis. This technique offers a user-friendly closed system for brain perfusion fixation which can be adapted for other tissues of the head, face and neck.
A smart thermoregulatory nanocomposite membrane with improved thermal properties: simultaneous use of graphene family and micro-encapsulated phase change material
Authors: Shemshadi R , Ghafarian R , Gorji M , Avazverdi E
Published: January 2018

This study is an attempt to improve the thermal properties of polyacrylamide (PAAm) membrane using graphene oxide (GO) and reduced graphene oxide (rGO) as a static modifier and phase change material micro-capsules (mPCMs) as a dynamic modifier at the same time. Fourier transform infra-red spectroscopy, X-ray diffraction and transmission electron microscopy were applied to prove GO and rGO synthesis. Dynamic heat transfer simulation apparatus and the transient heat transfer model were used to study the transient temperature behavior of the samples. Scanning electron microscopy and differential scanning calorimetry were also used to study the morphological properties and thermal behavior of hydrogels containing mPCMs. The addition of GO and rGO to the PAAm matrix increased thermal conductivity 2 and 2.5 times more than pure PAAm. Moreover, studying the transient temperature rates and mathematical simulations for PAAm containing GO and rGO revealed that rGO had better performance than GO in improving thermal properties. These hybrid nanocomposites increased the thermal conductivity of the fabrics thanks to the presence of rGO nanosheets and heat absorption capacity by mPCMs. It was also found that the presence of rGO improved the heat absorption performance of mPCMs to some extent. This long-awaited improvement in the thermal properties of the hydrogel membrane can be potentially harnessed to enhance user comfort in protective clothing.
Improved backstepping control for stochastic high-order nonlinear time delay system with a constructive mechanical system
Authors: Guo Long-Chuan , Liu Jian-Wei
Published: January 2018

In this paper, the backstepping control problem is addressed by backstepping technique for a class of high-order stochastic nonaffine nonlinear systems. Different from existing papers, the nonlinear vector terms of system depend on the unmeasurable states besides the measurable output, and replace the high order index from constant value to varying value in order to allow the result to apply to the more general situations. The maximum value interval of observer gain parameter is chosen to ensure the closed-loop system globally asymptotically stable in probability. The efficiency of the output-feedback controller is illustrated by a hydraulic mechanical system simulation.
Asymptotic stability of solutions of impulsive multi-delay differential equations
Authors: You Zhongli , Wang JinRong , O’Regan D
Published: January 2018

In this paper, we consider the asymptotic stability of solutions to impulsive multi-delayed differential equations with linear parts defined by pairwise permutable matrices. First, we introduce the concept for an impulsive multi-delayed Cauchy matrix and then use it to obtain the representation of solutions to linear impulsive Cauchy problems via the variation of constants principle. Next, we give a norm estimate of the impulsive multi-delayed Cauchy matrix and establish sufficient conditions to guarantee that the trivial solutions are asymptotically stable when the nonlinear terms satisfy appropriate conditions. Finally, two numerical examples are given to illustrate the effectiveness of the results.
The Amount and Source of Millionaires’ Wealth (Moderately) Predict Their Happiness
Authors: Donnelly Grant E. , Zheng Tianyi , Haisley Emily , Norton Michael I.
Published: January 2018

Two samples of more than 4,000 millionaires reveal two primary findings: First, only at high levels of wealth—in excess of US$8 million (Study 1) and US$10 million (Study 2)—are wealthier millionaires happier than millionaires with lower levels of wealth, though these differences are modest in magnitude. Second, controlling for total wealth, millionaires who have earned their wealth are moderately happier than those who inherited it. Taken together, these results suggest that, among millionaires, wealth may be likely to pay off in greater happiness only at very high levels of wealth, and when that wealth was earned rather than inherited.
‘Then we cannot be bought’
Authors: Smith Amy L
Published: January 2018

This article argues the courtships as performed in Love’s Labour’s Lost challenge early modern marital ideologies. By using performance theory to examine the women’s roles in particular, I argue that as the courtships unfold, the play highlights the particular ways that women emphasize their self-sufficient value by refusing to engage in banter or accept gifts that place them as an object of exchange. Thus the play ends, not as most Shakespearean comedies do by reminding us with overt performative self-consciousness that we have just watched a comedy, but rather that we have not.
Educating students with vision impairment today: Consideration of the expanded core curriculum
Authors: Opie Jill
Published: January 2018

A phenomenological study was undertaken giving students with vision impairment the opportunity to voice their experiences of secondary schooling in mainstream schools. Policies of inclusion were considered, with analysis of how training and curriculum came together, as experienced by these students, to develop their inclusion in schools in Victoria. Interviews of each participant using interpretative phenomenological analysis revealed a number of themes, with lack of teacher understanding of vision impairment a common theme across all cases. The limited access to visiting teachers, specialists in vision impairment, points to the need for alternatives in the delivery of necessary expanded core curriculum components. It is proposed that teachers of these students would benefit from an online unit to educate them in vision impairment to eliminate unintentional exclusion practices currently experienced and to encourage them to incorporate components of the expanded core curriculum into their everyday practices. The need for further research is indicated.
Quality of life of children and adolescents with visual impairment
Authors: Oliveira Olivete , Ribeiro Célia , Simões Cristina , Pereira Paulo
Published: January 2018

The conceptual framework of quality of life (QOL) have received considerable attention within students with visual impairment. The main purpose of this study was to analyse the QOL of children and adolescents with low vision and blindness. Data were collected from 18 children and adolescents, and respective parents ( n = 18). QOL was assessed by the KIDSCREEN 52 questionnaire. Cronbach’s alpha and correlations were calculated to examine the psychometric properties of the scale in the visual impairment field. The scale showed suitable internal consistency and construct validity. The findings highlighted that the mean scores were higher in participants with low vision, in male group, and in children. Furthermore, children and adolescents reported higher scores regarding their QOL than their parents. The results emphasized the importance of collecting information from the person about his or her own life to know the personal outcomes, as well as the perception of their parents.
Ghosting and destiny: Implicit theories of relationships predict beliefs about ghosting
Authors: Freedman Gili , Powell Darcey N. , Le Benjamin , Williams Kipling D.
Published: January 2018

Two studies examined how implicit theories of relationships are associated with ghosting (i.e., ending a relationship by cutting off all contact). Previous research on implicit theories of relationships has identified two types of beliefs, destiny and growth, and the present research examines how these implicit theories are associated with ghosting perceptions, intentions, and behaviors. Study 1 was an exploratory study conducted on Mechanical Turk that focused on romantic relationships ( N = 554). Study 2 was a confirmatory study conducted on Prolific Academic that aimed to replicate the romantic relationship findings and extended the research to friendships ( N = 747). Stronger destiny beliefs, compared to weaker destiny beliefs, were positively associated with feeling more positively toward ghosting, having stronger ghosting intentions, and having previously used ghosting to terminate relationships. Stronger growth beliefs, compared to weaker growth beliefs, showed the opposite pattern with perceptions of acceptability and intentions to use ghosting. Taken together, the present research provides an important first step in understanding how implicit theories relate to relationship termination strategies and, specifically, the process of ghosting.
Disclosure of Scandinavian telecom companies’ corruption in Uzbekistan: The role of investigative journalists
Authors: Pollack Ester , Allern Sigurd
Published: January 2018

Transparency International’s yearly Corruption Perceptions Index ranks Scandinavia as one of the least corrupt regions in the world. However, during the past decades, large Scandinavian corporations in the telecommunications, oil and defence industries have – in their struggle for business contracts in other countries – been involved in several large-scale bribery scandals. There has also been a growing range of corruption cases in the Swedish and Norwegian public sectors. In many of these cases, investigative journalists have played a crucial role in the disclosure of corruption, sometimes cooperating across media organisations and countries, demonstrating the importance of journalism as a public good for democracy. In this article, we explore, discuss and analyse the work of and methods used by investigative journalists in revealing large-scale corruption related to the expansion of Nordic telecom companies in Uzbekistan.
Measuring attitudes towards the dying process: A systematic review of tools
Authors: Groebe Bernadette , Strupp Julia , Eisenmann Yvonne , Schmidt Holger , Schlomann Anna , Rietz Christian , Voltz Raymond
Published: January 2018

Background:

At the end of life, anxious attitudes concerning the dying process are common in patients in Palliative Care. Measurement tools can identify vulnerabilities, resources and the need for subsequent treatment to relieve suffering and support well-being.

Aim:

To systematically review available tools measuring attitudes towards dying, their operationalization, the method of measurement and the methodological quality including generalizability to different contexts.

Design:

Systematic review according to the PRISMA Statement. Methodological quality of tools assessed by standardized review criteria.

Data sources:

MEDLINE, PsycINFO, PsyndexTests and the Health and Psychosocial Instruments were searched from their inception to April 2017.

Results:

A total of 94 identified studies reported the development and/or validation of 44 tools. Of these, 37 were questionnaires and 7 alternative measurement methods (e.g. projective measures). In 34 of 37 questionnaires, the emotional evaluation (e.g. anxiety) towards dying is measured. Dying is operationalized in general items ( n = 20), in several specific aspects of dying ( n = 34) and as dying of others ( n = 14). Methodological quality of tools was reported inconsistently. Nine tools reported good internal consistency. Of 37 tools, 4 were validated in a clinical sample (e.g. terminal cancer; Huntington disease), indicating questionable generalizability to clinical contexts for most tools.

Conclusion:

Many tools exist to measure attitudes towards the dying process using different endpoints. This overview can serve as decision framework on which tool to apply in which contexts. For clinical application, only few tools were available. Further validation of existing tools and potential alternative methods in various populations is needed.
Impact and Moderating Variables of an Intervention Promoting Physical Activity Among Children: Results From a Pilot Study
Authors: Gourlan Mathieu , Takito Monica , Lambert Céline , Fregeac Bruno , Alméras Natalie , Coste Olivier , Pereira Bruno , Cousson-Gélie Florence
Published: January 2018

This pilot study pursued three objectives: to assess the effect of a 1-month multilevel intervention on the PA of children, to assess the impact of the intervention on the theory of planned behavior (TPB) variables, and to evaluate the extent to which the impact of the intervention on PA and TPB variables varied according to personal (i.e., gender and age) and situational (i.e., class and school) moderating variables. Children were aged 7 to 11 years ( n = 306). Analyses revealed a significant increase of PA practice and TPB variables ( ps < .001). Age (i.e., being a younger child) was associated with a higher increase on attitude and perceived control ( ps < .01). The class or the school levels explained a meaningful variance in the evolution of PA or TPB variables (intraclass correlation coefficients > .10). The present study reports the interest and feasibility of a multilevel intervention to increase PA and TPB variables in children.
Evaluation of an iterative model-based CT reconstruction algorithm by intra-patient comparison of standard and ultra-low-dose examinations
Authors: Noël Peter B , Engels Stephan , Köhler Thomas , Muenzel Daniela , Franz Daniela , Rasper Michael , Rummeny Ernst J , Dobritz Martin , Fingerle Alexander A
Published: January 2018

Background

The explosive growth of computer tomography (CT) has led to a growing public health concern about patient and population radiation dose. A recently introduced technique for dose reduction, which can be combined with tube-current modulation, over-beam reduction, and organ-specific dose reduction, is iterative reconstruction (IR).

Purpose

To evaluate the quality, at different radiation dose levels, of three reconstruction algorithms for diagnostics of patients with proven liver metastases under tumor follow-up.

Material and Methods

A total of 40 thorax–abdomen–pelvis CT examinations acquired from 20 patients in a tumor follow-up were included. All patients were imaged using the standard-dose and a specific low-dose CT protocol. Reconstructed slices were generated by using three different reconstruction algorithms: a classical filtered back projection (FBP); a first-generation iterative noise-reduction algorithm (iDose4); and a next generation model-based IR algorithm (IMR).

Results

The overall detection of liver lesions tended to be higher with the IMR algorithm than with FBP or iDose4. The IMR dataset at standard dose yielded the highest overall detectability, while the low-dose FBP dataset showed the lowest detectability. For the low-dose protocols, a significantly improved detectability of the liver lesion can be reported compared to FBP or iDose4 ( P = 0.01). The radiation dose decreased by an approximate factor of 5 between the standard-dose and the low-dose protocol.

Conclusion

The latest generation of IR algorithms significantly improved the diagnostic image quality and provided virtually noise-free images for ultra-low-dose CT imaging.
Promoting undergraduate student engagement through self-generated exam activity
Authors: Muñoz-Escalona Patricia , Savage Kathleen , Conway Fiona , McLaren Andrew
Published: January 2018

Self-generated exam activity was implemented in second year undergraduate students of Mechanical and Aerospace Engineering degree to promote engagement. The activity was demonstrated to be effective regarding enhancement of learning outcomes through the promotion of deep learning and partnership through cooperative and collaborative work. Results indicated that ∼80% of the students engaged with the activity and were satisfied with the learning outcomes. In general, students (>80%) perceived themselves as co-creators and co-owners of the self-generated exam. Results also showed that academic staff encouragement and motivation affects students’ co-creation and that students are satisfied when involved in their learning process.
Artificial Aortic Valves: An Overview
Authors: Morsi Y.S. , Birchall I.E. , Rosenfeldt F.L.
Published: January 2018

This review discusses strategies that may address some of the limitations associated with replacing diseased or dysfunctional aortic valves with mechanical or tissue valves. These limitations range from structural failure and thromboembolic complications associated with mechanical valves to a limited durability and calcification with tissue valves. In pediatric patients there is an issue with the inability of substitutes to grow with the recipient. The emerging science of tissue engineering potentially provides an attractive alternative by creating viable tissue structures based on a resorbable scaffold. Morphometrically precise, biodegradable polymer scaffolds may be fabricated from data obtained from scans of natural valves by rapid prototyping technologies such as fused deposition modelling. The scaffold provides a mechanical profile until seeded cells produce their own extra cellular matrix. The microstructure of the forming tissue may be aligned into predetermined spatial orientations via fluid transduction in a bioreactor. Although there are many technical obstacles that must be overcome before tissue engineered heart valves are introduced into routine surgical practice these valves have the potential to overcome many of the shortcomings of current heart valve substitutes.
Mathematical Model of Platelet Deposition under Flow Conditions
Authors: Affeld K. , Goubergrits L. , Kertzscher U. , Gadischke J. , Reininger A.
Published: January 2018

Platelet deposition in resting blood is well researched and understood. However, the influence of hemodynamic parameters such as wall shear rate is less clear. Clinical experience and experiments show an interaction between flow and platelet deposition. But a complete understanding of the flow influence and hence a quantification has not yet been achieved. A well defined experiment of flow dependant platelet depositions is the stagnation point flow. This kind of flow is ubiquitous in the circulatory system, to be found in every bifurcation and recirculation region. These are the areas where thrombus formations are likely to occur if other conditions are also met. First, experiments were performed in a stagnation point flow chamber. A simplified blood model, platelet rich plasma, was used as a test fluid. With a microscope the platelet deposition was observed and recorded. Platelets deposit in a characteristic pattern showing the influence of the flow. An analysis of this pattern is the objective of this study and is achieved with the help of a numerical model, which is based on a convective diffusive transport. The model results in a platelet deposition pattern, which in its shape and temporal development is very similar to experimental results. Hence it is concluded that the assumed transport processes are causal for platelet depositions and thrombus formation.
Serum Tonicity, Extracellular Volume and Clinical Manifestations in Symptomatic Dialysis-Associated Hyperglycemia Treated Only with Insulin
Authors: Tzamaloukas A.H , Rohrscheib M. , Ing T.S. , Siamopoulos K.C. , Elisaf M.S. , Spalding C.T.
Published: January 2018

The absence of osmotic diuresis modifies the effects of hyperglycemia on body fluids in patients with advanced renal failure. To determine the relationship between clinical manifestations and abnormalities in tonicity and extracellular volume in such patients, we analyzed 43 episodes of severe dialysis-associated hyperglycemia (serum glucose exceeding 600 mg/dL) treated only with insulin. The main manifestations were dyspnea in 22 cases (pulmonary edema in 19), nausea and vomiting in 15, coma in 13 and seizures in 3, while 5 patients had no symptoms. Treatment with insulin resulted in a decrease in serum glucose value from 913 ± 197 mg/dL to 170 ± 78 mg/dL, an increase in serum sodium level from 125 ± 5 to 136 ± 5 mmol/L, and a fall in calculated serum tonicity value from 300 ± 13 to 282 ± 11 mmol/kg (all at p < 0.001). The ratio of the change in serum sodium level over change in serum glucose concentration was –1.50 ± 0.22 mmol/L per 100 mg/dL. The percent increase in extracellular volume secondary to hyperglycemia developing from the prior euglycemic state and calculated from changes in serum sodium and chloride concentrations, was 10.9% ± 4.6% (1.5% ± 0.6% per 100 mg/dL increase in serum glucose level). All clinical manifestations dissipated after correction of hyperglycemia in 42 patients. One woman developed during treatment a fatal myocardial infarction. Dialysis patients with severe hyperglycemia may develop symptoms as a result of hypertonicity and extracellular expansion. Insulin alone may be sufficient treatment for these symptoms. The changes in serum tonicity and electrolytes during treatment are consistent with theoretical predictions.
Natural Killer Cell Activity Unaffected by Ozonated Autohemotherapy in Patients with End-Stage Renal Disease on Maintenance Renal Replacement Therapy
Authors: Biedunkiewicz B. , Tylicki L , Rachon D. , Hak L. , Nieweglowski T. , Chamienia A. , Debska-Slizien A. , Mysliwska J. , Rutkowski B.
Published: January 2018

Ozonotherapy is a complementary medical approach in the treatment of resistant infections, immune deficiency syndromes, orthopedic pathologies and vascular diseases. The criticism of this method is associated with potentially harmful effects of ozone on cells. The aim of this study was to investigate the influence of ozonated autohemotherapy (O3-AHT) on the cellular response of the immunologic system represented by cytotoxic activity of natural killer cells. 12 hemodialyzed patients (8 M, 4 F) aged 64.8±7.6 years with peripheral arterial disease as the main reason for the treatment with O3-AHT were examined in a prospective, placebo controlled, single blind study. They received 9 sessions of autohemotherapy without ozone exposure as a placebo-control and subsequent 9 sessions of O3-AHT. The procedures were performed 3 times a week, just before hemodialysis session. Ozone-oxygen gas mixture with ozone concentration of 50 μg/ml produced by ozone generator (ATO3, KrioMetrum, Poland) was used during O3-AHT. Natural killer cell activity was measured using lactate dehydrogenase release assay. There was no statistical difference between natural killer cell activity (%) at the baseline (16.78±8.07), after nine sessions of control autohemotherapy (15.98±6.67), and after nine sessions of O3-AHT (18.26±8.82). In conclusion, our findings showed that O3-AHT in a dose of 50 mg/mL does not have any significant influence on natural killer cell function in hemodialyzed patients.
CKD Patients and Erythropoietin: Do We Need Evidence-Based Informed Consent?
Authors: Mezza E. , Consiglio V. , Soragna G. , Putaggio S. , Burdese M. , Perrotta L. , Jeantet A. , Segoloni G.P. , Piccoli G.B.
Published: January 2018

Background

Consent to therapy is increasingly requested in the form of “informed consent”.

Objective

To validate an evidence-based informed consent form for erythropoietin (EPO) therapy and to evaluate patient opinions about the informed consent approach.

Methods

An evidence-based informed consent form was developed as part of the Evidence-Based-Medicine course at the Medical School of Turin, Italy. It was validated by anonymous questionnaires (0–10 analogical scales and open answers) administered to patients at different stages of CKD (19 pre-ESRD, 26 hemodialysis, 12 transplant patients) attending an outpatient unit of the University of Turin, to 8 nurses, and to 26 medical students.

Results

All individuals filled in the questionnaire. Interest in a detailed explanation of the therapy was high (median 9), as was comprehension (median 9), with no differences between patients with regard to disease stage (pre-ESRD vs. RRT) or educational level. Prior knowledge of the therapy was affected by the educational level (p=0.013 for the advantages and p=0.004 for the side effects) and the professional role (patients vs caregivers: p=0.009 for the advantages and p<0.001 for side affects); patient knowledge of the advantages (median 6) tended to increase as the disease progressed (p=0.015). The most common response by patients was that informed consent was necessary for all drugs (35.1%); 73.1% of the caregivers considered it necessary only for severe side effects. The preferred modality of consent was discussion with the caregiver during the clinical controls (42% of all cases).

Conclusions

Patient interest in and comprehension of an informed consent form with a detailed explanation of the therapy was high; the caregiver's opinion was still the most valued teaching tool.
Rheological Characterization of an Artificial Synovial Fluid
Authors: Casentini G. , Di Paola L. , Marrelli L. , Palma F.
Published: January 2018

Rheological measurements on two classes of artificial synovial fluids have been carried out in the attempt to get a suitable but cheap lubricant for wear tests of prosthetic materials. Fluids of both classes are solutions of hyaluronic acid (HA) that, for one class, is dissolved into a simple Ringer solution whereas, for the other class, into a mixture of human serum and Ringer solution. Similar rheological properties have been observed for both classes of fluids.

Experimental results have been interpreted by two classical models that are commonly used in the literature to describe the rheological behavior of colloidal systems and of polymer solutions with high entanglement density, respectively.

The quality of correlations shows that, at high HA concentrations, entagled structures are largely present and cannot be neglected.
Determination of VIT 45 (IND#63,243 - American Regent) Removal by Closed Loop in Vitro Hemodialysis System
Authors: Manley H.J. , McClaran M.L.
Published: January 2018

Background

Intravenous iron is typically administered during the hemodialysis (HD) procedure. The extent of VIT 45, a novel intravenous iron formulation, removal by high-flux (HF) or high-efficiency (HE) dialysis membranes at various ultrafiltration rates (UFR) is unknown.

Methods

An in vitro HD system was constructed to determine the dialyzabiltiy of iron from a normal saline compartment (NSC) containing 1000 mg iron of VIT 45. The in vitro system utilized a 6-L closed-loop SBS system that was subject to 4 different HD conditions conducted over 4 hours: HE membrane + 0 ml/h UFR; HE membrane + 500 ml/h UFR; HF membrane + 0 ml/h UFR; HF membrane + 500 ml/h UFR. Blood flow and dialysate flow rates were 500 ml/min and 800 ml/min, respectively. The dialysate compartment was a 6-L closed-loop system. A volumetric HD machine controlled all blood, dialysate, and ultrafiltration rates. NSC and dialysate compartment samples were taken at various time points and iron elimination rate (khd) and HD clearance (Clhd) was determined. Iron removal from the NSC > 15% was considered clinically significant.

Results

The percent removal of iron from the NSC was < 0.5% at all time points in the study. Dialysate recovery of iron was negligible: 1.7–5.1 mg. VIT 45 removal elimination rates from NSC were less than -0.001 h −1 (range -0.0002 ± 0.0001 to -0.0001 ± 0.0002 h −1) for all study conditions. Dialyzer type or UFR did not effect iron removal.

Conclusion

HF or HE dialysis membranes do not remove clinically significant amounts of VIT 45 over a 4-hour in vitro HD session. This effect remained constant even controlling for UFR up to 500 ml/hour. VIT 45 is not dialyzed by HE or HF dialysis membranes irrespective of UFR. (Int J Artif Organs 2006; 29: 1062–6)
Inadequacy of Dialysis, Chronic Inflammation and Malnutrition in Nigerian Patients on Chronic Hemodialysis
Authors: Tzamaloukas A.H. , Vanderjagt D.J. , Agaba E.I. , Ma I. , Lopez A. , Tzamaloukas R.A. , Murata G.H. , Glew R.H.
Published: January 2018

Purpose

To identify the extent of underdialysis, chronic inflammation and malnutrition and their interrelationships in Nigerian hemodialysis patients.

Methods

In a prospective study including 10 adult patients, (6 men, 4 women) on hemodialysis in North Central Nigeria, malnutrition was assessed by body mass index (BMI), serum albumin and prealbumin, and bioimpedance (BIA) pre-and post dialysis, inflammation was evaluated by C-reactive protein (CRP) and adequacy of dialysis was judged by frequency of the hemodialysis sessions and Kt/V urea.

Results

Post-dialysis BMI was 21.3 (19.9, 24.3) kg/m2 (< 20 kg/m2 in 4 patients), serum albumin 31.5 (24.0, 32.0) g/L (< 30.0 g/L in 5), serum pre-albumin 25.2 (15.3, 31.1) mg/dL (< 18.0 mg/dL in 4), serum CRP 4.8 (1.2, 11.5) mg/dL (> 1.0 mg/dL in 8), phase angle 4.2 (3.7, 5.1)° (< 3° in 3) and body fat deficit was diagnosed by BIA in 4 patients. Weekly frequency of dialysis was 3 times in 2 patients, twice in 1 and ≤1 time in 7. Single-pool Kt/V urea was 0.81 (0.68, 0.95, <1.2 in 9 patients and > 1.2 in one patient receiving dialysis only twice weekly). By combined frequency of dialysis and Kt/V urea values, no patient received an adequate dose of dialysis and, indeed, all patients had overt symptoms of uremia. Low body weight, low serological and BIA nutrition indices, and high CRP levels occurred in the same patients. Patients on dialysis for > 1 year had worse nutrition indices than those on dialysis for < 1 year.

Conclusions

Underdialysis was universal, while poor nutrition and chronic malnutrition were found in the majority of the small number of patients studied. These three adverse conditions, which were interlinked, may be common in Nigerian hemodialysis patients, because their underlying socioeconomic causes are widespread. (Int J Artif Organs 2006; 29: 1067–73)
The “French Hemodiafe Trial”: This Study is Neither Decisive nor Definitive in Resolving the Controversy on Renal Replacement Therapy in ICU
Authors: Honore P.M. , Joannes-Boyau O.
Published: January 2018

This short review paper addresses a recently published study on the controversy concerning the type of renal replacement therapy (RRT) used in ICU. It proposes a somewhat different point of view regarding this study, based on the numerous problems that have been identified with it. Indeed, given these shortcomings, the study conclusions are somewhat misleading and are not effectively supported by the trial data. If the treatment doses were comparable and kept constant in the “IHD” group, then the results may well have been strikingly different. In keeping with all drugs used in medicine, dose is crucial and should have remained unchanged by the investigators during the study in order to be able to draw valid conclusions based on the evidence. There is a need for a further study comparing CRRT and IHD. This should be better designed in terms of the exclusion criteria, delivered dose of CVVH (35 ml/kg/h) and IHD, timing of treatment and should also examine more secondary endpoints. This may answer many of the outstanding issues and provide a balanced opinion about this study and its real importance in ICU practice. Finally, this study does not have the scientific power (as explained by the accompanying editorial by Kellum) to put an end to the ICU controversy regarding the choice of RRT in acute renal failure while in ICU. Therefore, there is an urgent need for a better designed study regarding this controversy.
Time-Resolved PIV Technique for High Temporal Resolution Measurement of Mechanical Prosthetic Aortic Valve Fluid Dynamics
Authors: Kaminsky R. , Morbiducci U. , Rossi M. , Scalise L. , Verdonck P. , Grigioni M.
Published: January 2018

Prosthetic heart valves (PHVs) have been used to replace diseased native valves for more than five decades. Among these, mechanical PHVs are the most frequently implanted. Unfortunately, these devices still do not achieve ideal behavior and lead to many complications, many of which are related to fluid mechanics. The fluid dynamics of mechanical PHVs are particularly complex and the fine-scale characteristics of such flows call for very accurate experimental techniques. Adequate temporal resolution can be reached by applying time-resolved PIV, a high-resolution dynamic technique which is able to capture detailed chronological changes in the velocity field. The aim of this experimental study is to investigate the evolution of the flow field in a detailed time domain of a commercial bileaflet PHV in a mock-loop mimicking unsteady conditions, by means of time-resolved 2D Particle Image Velocimetry (PIV). The investigated flow field corresponded to the region immediately downstream of the valve plane. Spatial resolution as in “standard” PIV analysis of prosthetic valve fluid dynamics was used. The combination of a Nd:YLF high-repetition-rate double-cavity laser with a high frame rate CMOS camera allowed a detailed, highly temporally resolved acquisition (up to 10000 fps depending on the resolution) of the flow downstream of the PHV. Features that were observed include the non-homogeneity and unsteadiness of the phenomenon and the presence of large-scale vortices within the field, especially in the wake of the valve leaflets. Furthermore, we observed that highly temporally cycle-resolved analysis allowed the different behaviors exhibited by the bileaflet valve at closure to be captured in different acquired cardiac cycles.

By accurately capturing hemodynamically relevant time scales of motion, time-resolved PIV characterization can realistically be expected to help designers in improving PHV performance and in furnishing comprehensive validation with experimental data on fluid dynamics numeric modelling.