bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity-Enhanced Fourier Transform Mid-Infrared Spectroscopy Using a Supercontinuum Laser Source
Authors: Zorin Ivan , Kilgus Jakob , Duswald Kristina , Lendl Bernhard , Heise Bettina , Brandstetter Markus
Published: February 2020

Fourier transform infrared (FT-IR) spectrometers have been the dominant technology in the field of mid-infrared (mid-IR) spectroscopy for decades. Supercontinuum laser sources operating in the mid-IR spectral region now offer the potential to enrich the field of FT-IR spectroscopy due to their distinctive properties, such as high-brightness, broadband spectral coverage and enhanced stability. In our contribution, we introduce this advanced light source as a replacement for conventional thermal emitters. Furthermore, an approach to efficient coupling of pulsed mid-IR supercontinuum sources to FT-IR spectrometers is proposed and considered in detail. The experimental part is devoted to pulse-to-pulse energy fluctuations of the applied supercontinuum laser, performance of the system, as well as the noise and long-term stability. Comparative measurements performed with a conventional FT-IR instrument equipped with a thermal emitter illustrate that similar noise levels can be achieved with the supercontinuum-based system. The analytical performance of the supercontinuum-based FT-IR spectrometer was tested for a concentration series of aqueous formaldehyde solutions in a liquid flow cell (500 µm path length) and compared with the conventional FT-IR (130 µm path length). The results show a four-times-enhanced detection limit due to the extended path length enabled by the high brightness of the laser. In conclusion, FT-IR spectrometers equipped with novel broadband mid-IR supercontinuum lasers could outperform traditional systems providing superior performance, e.g., interaction path lengths formerly unattainable, while maintaining low noise levels known from highly stable thermal emitters.
A Theory of Demographically Targeted Repression
Authors: Rozenas Arturas
Published: February 2020

People from specific ethnic, religious, or other externally identifiable groups are often subjected to harsher repression than others. This phenomenon of demographically targeted repression is often viewed as a result of xenophobia. I provide a rationalist explanation of demographic targeting to understand why this form of repression is employed even without xenophobic motives. Building on the empirical literature, I model an environment where a threat of repression may motivate people to oppose the regime defensively. I show that, in such conditions, the regime may use demographic targeting to undermine cross-group collective action. The model explains when demographic targeting is used and how it shapes the behavior and identity of citizens. I use the model to make sense of certain aspects of repression policy in China.
A Critical Examination of Turkish Language Teaching Curriculum From an Interactionist Perspective
Authors: Soysal Y. , Radmard S. , Murat M.
Published: February 2020

This study explored the Turkish language teaching curriculum (TLTC, Grades 1–8) outcomes through an interactionist framework. Two points framed the analysis of the outcomes: learning demand and social discussions of the meanings. This study concluded that particularly for the learning areas such as reading, speaking, and writing, sixth- to eighth-grade outcomes downgrade the opportunities of teachers to engage students in social discussion of meaning when teaching Turkish language due to lower learning demand compared with first- to fifth-grade outcomes. First- to fifth-grade outcomes were found to provide Turkish language teachers more chances to create social discussions of meaning by enhancing the learning demand.
A New Model of Christian Leadership: Insights from the Job Demands–Resources Model and Trinitarian Theology
Authors: Miner Maureen , Bickerton Grant
Published: February 2020

Much secular research into leadership examines the traits and behaviors of leaders towards valued organizational goals. Similarly, biblical approaches to Christian leadership examine the traits and activities of biblical figures towards God’s kingdom ends. However, these and relational theories of Christian leadership such as the incarnational approach of servant leadership and the motivational approach of transformational leadership have been criticized. In this article we review research findings based on the Job Demands–Resources model of organizational behavior, in which personal resources of the leader interact with job characteristics in order to increase valued outcomes of work engagement, reduced turnover, and other indicators of healthy functioning. Spiritual resources, such as a secure attachment relationship with God, are examined as a subcategory of personal resources. We consider the results in terms of a trinitarian approach to relational leadership and propose a Trinitarian Resources Model of leadership. We suggest that questions such as “How do I best express my faith in my leadership?” (orthopraxy) can be partly answered in terms of trinitarian theology (orthodoxy) that highlights the relational nature of God, God’s creation of a relational universe, the centrality of kenosis, and the work of the Holy Spirit to embrace and empower humans at work for God’s kingdom ends.
Tracheostomy in the Extremely Premature Neonate: A Multi‐Institutional Study
Authors: Pereira Kevin D. , Shaigany Kevin , Zur Karen B. , Jenks Carolyn M. , Preciado Diego A. , Hamdi Osama , Banker Karen , Briddell Jenna W. , Isaiah Amal
Published: February 2020

Objective

(1) To describe characteristics associated with tracheostomy placement and (2) to describe associated in‐hospital morbidity in extremely premature infants.

Study Design

Pooled retrospective analysis of charts.

Setting

Academic children’s hospitals.

Subjects and Methods

The patient records of premature infants (23‐28 weeks gestational age) who underwent tracheostomy between January 1, 2012, and December 31, 2017, were reviewed from 4 academic children’s hospitals. Demographics, procedural morbidity, feeding, respiratory, and neurodevelopmental outcomes at the time of transfer from the neonatal intensive care unit (NICU) were obtained. The contribution of baseline characteristics to mortality, neurodevelopmental, and feeding outcomes was also assessed.

Results:

The charts of 119 infants were included. The mean gestational age was 25.5 (95% confidence interval, 25.2‐25.7) weeks. The mean birth weight was 712 (671‐752) g. Approximately 50% was African American. The principal comorbidity was chronic lung disease (92.4%). Overall, 60.5% of the infants had at least 1 complication. At the time of transfer, most remained mechanically ventilated (94%) and dependent on a feeding tube (90%). Necrotizing enterocolitis increased the risk of feeding impairment (P =. 002) and death (P =. 03).

Conclusions

Tracheostomy in the extremely premature neonate is primarily performed for chronic lung disease. Complications occur frequently, with skin breakdown being the most common. Placement of a tracheostomy does not seem to mitigate the systemic morbidity associated with extreme prematurity.
Impact of Time to Diagnosis and Treatment in Head and Neck Cancer: A Systematic Review
Authors: Schutte Henrieke W. , Heutink Floris , Wellenstein David J. , van den Broek Guido B. , van den Hoogen Frank J. A. , Marres Henri A. M. , van Herpen Carla M. L. , Kaanders Johannes H. A. M. , Merkx Thijs M. A. W. , Takes Robert P.
Published: February 2020

Objective

An increased interval between symptomatic disease and treatment may negatively influence oncologic and/or functional outcomes in head and neck cancer (HNC). This systematic review aims to provide insight into the effects of time to treatment intervals on oncologic and functional outcomes in oral cavity, pharyngeal, and laryngeal cancer.

Data Sources

PubMed, EMBASE, and Cochrane library were searched.

Review Methods

All studies on delay or time to diagnosis or treatment in oral, pharyngeal, and laryngeal cancer were included. Quality assessment was performed with an adjusted version of the Newcastle‐Ottawa scale. Outcomes of interest were tumor volume, stage, recurrence, survival, patient‐reported outcome measures (PROMs), toxicity, and functionality after treatment.

Results

A total of 51 studies were included. Current literature on the influence of delay in HNC is inconsistent but indicates higher stage and worse survival with longer delay. The effects on PROMs, toxicity, and functional outcome after treatment have not been investigated. The inconsistencies in outcomes were most likely caused by factors such as heterogeneity in study design, differences in the definitions of delay, bias of results, and incomplete adjustment for confounding factors in the included studies.

Conclusion

Irrespective of the level of evidence, the unfavorable effects of delay on oncologic, functional, and psychosocial outcomes are undisputed. Timely treatment while maintaining high‐quality diagnostic procedures and decision making reflects good clinical practice in our opinion. This review will pose practical and logistic challenges that will have to be overcome.
Pardhi Criminality in Postcolonial Chhattisgarh—of Tigers, Tribals and Misfits
Authors: Sharma Varun
Published: February 2020

Efforts aimed at canvassing the past–present continuum of criminal tribes, though appreciable, have proven to be piecemeal, sporadic and awkward. Avoiding some characteristic pitfalls, a historical anthropology of the Pardhis of Chhattisgarh reveals how geographies that were relatively untouched by a colonial programme of criminalization before independence can become active sites of the same in the post-independence period. In avoiding either extremes of emphasizing absolute continuities or alternatively marking a putative rupture between the (colonial) past and (postcolonial) present, this article makes a case for how the colonial programme frequently mutates with/through a number of other discourses, such as regional state formation, administrative procedures, wildlife conservation, nascent ideas of tribal development, and democratic struggles, as part of its relentless movement. This article summarizes the effects of the same for the Pardhis at the level of ‘history’.
Molecular and Biological Characterization of a Cervidpoxvirus Isolated From Moose with Necrotizing Dermatitis
Authors: Armién Anibal G. , Wolf Tiffany M. , Mor Sunil Kumar , Ng Terry Fei Fan , Bracht Alexa J. , Goyal Sagar M. , Rasmussen James M.
Published: February 2020

Cervidpoxvirus is one of the more recently designated genera within the subfamily Chordopoxvirinae, with Deerpox virus (DPV) as the only recognized species to date. In this study, the authors describe spontaneous disease and infection in the North American moose ( Alces americanus) by a novel Cervidpoxvirus, here named Moosepox virus (MPV). Three 4-month-old moose calves developed a multifocal subacute-to-chronic, necrotizing, suppurative-to-granulomatous dermatitis that affected the face and the extremities. Ultrastructurally, all stages of MPV morphogenesis—that is, crescents, spherical immature particles, mature particles, and enveloped mature virus—were observed in skin tissue. In vitro infection with MPV confirmed that its morphogenesis was similar to that of the prototype vaccinia virus. The entire coding region, including 170 putative genes of this MPV, was sequenced and annotated. The sequence length was 164,258 bp with 98.5% nucleotide identity with DPV (strain W-1170-84) based on the whole genome. The genome of the study virus was distinct from that of the reference strain (W-1170-84) in certain genes, including the CD30-like protein (83.9% nucleotide, 81.6% amino acid), the endothelin precursor (73.2% nucleotide including some indels, 51.4% amino acid), and major histocompatibility class (MHC) class I–like protein (81.0% nucleotide, 68.2% amino acid). This study provides biological characterization of a new Cervidpoxvirus attained through in vivo and in vitro ultrastructural analyses. It also demonstrates the importance of whole-genome sequencing in the molecular characterization of poxviruses identified in taxonomically related hosts.
Spontaneous KRT5 Gene Mutation in Rhesus Macaques (Macaca mulatta): A Novel Nonhuman Primate Model of Epidermolysis Bullosa Simplex
Authors: Johnson Amanda L. , Peterson Samuel M. , Terry Margaret M. L. , Ferguson Betsy , Colgin Lois M. , Lewis Anne D.
Published: February 2020

Epidermolysis bullosa simplex (EBS) is an inherited skin disorder characterized by increased skin and mucous membrane fragility. Most cases are caused by mutations in keratin 5 ( KRT5) and keratin 14 ( KRT14). Mutations of these genes result in cytoskeletal disruption of the basal keratinocytes. Gross and histopathologic findings of 2 clinically affected homozygous rhesus macaques with an insertion variant mutation in KRT5 are described and compared with 6 deceased phenotypically normal animals that were heterozygous for the KRT5 insertion variant. Animals that were homozygous for the KRT5 insertion variant were stillborn and had widespread loss of the epidermis. Microscopic examination confirmed severe ulceration and basal cell vacuolation with basilar vesicle formation in the remaining intact epidermis. Immunohistochemistry for cytokeratin 5 demonstrated lack of epidermal immunoreactivity in homozygotes. DNA sequencing identified a 34–base pair insertion variant in exon 5 of the KRT5 gene. To our knowledge, this is the first report of epidermolysis bullosa in rhesus macaques.
Myocardial Changes in Diabetic and Nondiabetic Nonhuman Primates
Authors: Krog Simone , Ludvigsen Trine P. , Nielsen Ole L. , Kirk Rikke K. , Lykkegaard Kirsten , Wulff Erik M. , Møller Jacob E. , Pedersen Henrik D. , Olsen Lisbeth H.
Published: February 2020

Diabetic human patients have increased risk of heart failure compared to healthy subjects. The underlying mechanisms for this are not fully understood, and to help develop improved treatment strategies, well-characterized animal models are essential. To investigate cardiac dysfunction in diabetes, this study evaluated myocardial changes in 10 aging rhesus monkeys with and without diabetes. Based on evaluation of plasma glycosylated hemoglobin and glucose, 7 of 10 rhesus macaques had diabetes for a minimum of 11 months, while 3 of 10 were categorized as nondiabetic. A detailed histological examination of formalin-fixed left ventricular myocardial samples was followed by a semiquantitative evaluation of myocardial fibrosis and fat infiltration; digital quantifications of myocardial collagen, lipofuscin, and nuclear area fractions; and measurements of cardiomyocyte diameter. Histological myocardial evaluation revealed the presence of lipofuscin; large nuclei; interstitial, replacement, and vascular fibrosis; adipocyte infiltration; and vacuolar degeneration with atrophy of cardiomyocytes and fibrosis. However, there were no differences between groups for semiquantitative fat infiltration, fibrosis, cardiomyocyte size, collagen, or nuclear and lipofuscin area fraction. Lipofuscin area fraction correlated with plasma insulin, triglyceride, total cholesterol, and high-density lipoprotein cholesterol concentrations. In conclusion, myocardial pathological changes were found in left ventricular myocardium in aged rhesus macaques, independent of the stage of diabetes. The duration of diabetes might have been too short to cause differences between groups.
Oxidative damage in the liver and kidney induced by dermal exposure to diisononyl phthalate in Balb/c mice
Authors: Liang Feng , Yan Biao
Published: February 2020

As a general alternative, diisononyl phthalate (DINP) has gradually replaced di(2-ethylhexyl) phthalate (DEHP) as the main plasticizer used in polyvinyl chloride. Like DEHP, DINP can also be released into the environment, resulting in humans being exposed through skin contact. This study aims to explore whether oxidative damage to hepatic and renal tissues can be induced by dermal exposure to DINP in mice. Forty-two male Balb/c mice were divided into six groups. The five DINP dermal exposure groups were exposed to different doses of DINP (0.02, 0.2, 2, 20, and 200 mg/kg) for 28 consecutive days. The pathological alterations to the skin, liver, and kidney in the mice were examined. Levels of reactive oxygen species (ROS), reduced glutathione (GSH), malondialdehyde (MDA), and DNA-protein cross-links (DPC) in the liver and kidney were also determined to investigate oxidative damage. The experimental results showed that the levels of ROS, MDA, and DPC coefficients increased gradually in a dose-dependent manner, whereas the level of GSH decreased accordingly. When the exposure dose was ≥20 mg/kg, ROS, GSH, MDA content, and the DPC coefficient were significantly different compared to the control group ( p < 0.05). These results suggest that a high dose of DINP can induce oxidative stress and histopathological alterations in the liver and kidney via dermal exposure.
A Computational Error and Restricted Use of Time-series Analyses Underlie the Failure to Replicate period-Dependent Song Rhythms in Drosophila
Authors: Kyriacou Charalambos P. , Dowse Harold B. , Zhang Lin , Green Edward W.
Published: February 2020

From 1980 to 1991, Kyriacou, Hall, and collaborators (K&H) reported that the Drosophila melanogaster courtship song has a 1-min cycle in the length of mean interpulse intervals (IPIs) that is modulated by circadian rhythm period mutations. In 2014, Stern failed to replicate these results using a fully automated method for detecting song pulses. Manual annotation of Stern’s song records exposed a ~50% error rate in detection of IPIs, but the corrected data revealed period-dependent IPI cycles using a variety of statistical methods. In 2017, Stern et al. dismissed the sine/cosine method originally used by K&H to detect significant cycles, claiming that randomized songs showed as many significant values as real data using cosinor analysis. We first identify a simple mathematical error in Stern et al.’s cosinor implementation that invalidates their critique of the method. Stern et al. also concluded that although the manually corrected wild-type and perL mutant songs show similar periods to those observed by K&H, each song is usually not significantly rhythmic by the Lomb-Scargle (L-S) periodogram, so any genotypic effect simply reflects “noise.” Here, we observe that L-S is extremely conservative compared with 3 other time-series analyses in assessing the significance of rhythmicity, both for conventional locomotor activity data collected in equally spaced time bins and for unequally spaced song records. Using randomization of locomotor and song data to generate confidence limits for L-S instead of the theoretically derived values, we find that L-S is now consistent with the other methods in determining significant rhythmicity in locomotor and song records and that it confirms period-dependent song cycles. We conclude that Stern and colleagues’ failure to identify song cycles stems from the limitations of automated methods in accurately reflecting song parameters, combined with the use of an overly stringent method to discriminate rhythmicity in courtship songs.
Peritoneal Dialysis: Better than, Equal to, or Worse than Hemodialysis? Data Worth Knowing before Choosing a Dialysis Modality
Authors: Thodis Elias , Passadakis Ploumis , Vargemezis Vassilis , Oreopoulos Dimitrios G.
Published: February 2020

Technological advances such as those that allow the delivery of an adequate dialysis dose to a larger percentage of patients, minimization of peritoneal membrane damage with more biocompatible solutions, and lower peritonitis rates will undoubtedly improve retention of patients on peritoneal dialysis (PD) for longer periods. Currently, only 15% of the world dialysis population is managed by PD. Peritoneal dialysis has many advantages over hemodialysis, and if end-stage renal disease (ESRD) patients are fully informed about them, the proportion of patients who would prefer this treatment would rise to 25% – 30%. An integrated approach to the treatment of ESRD could start with PD in a large percentage of patients, especially those who will receive a kidney transplant within 2 – 3 years. With the present epidemic of ESRD, this approach could lead to a significant saving, relieve the pressure on dialysis units, and allow a larger number of ESRD patients to be treated.
Blood Pressure and Left Ventricular Hypertrophy in Patients on Different Peritoneal Dialysis Regimens
Authors: Wang Ming-Cheng , Tseng Chin-Chung , Tsai Wei-Chuan , Huang Jeng-Jong
Published: February 2020

Objective

To examine the relation between the results of ambulatory 24-hour blood pressure monitoring (ABPM) and left ventricular mass index (LVMI), then to find the independent determinant for left ventricular hypertrophy (LVH) in peritoneal dialysis (PD) patients. Finally, to evaluate the differences in the clinical and cardiovascular characteristics between patients on continuous ambulatory PD (CAPD) and continuous cyclic PD (CCPD).

Design

An open, nonrandomized, cross-sectional study.

Setting

Divisions of nephrology and cardiology in a medical center.

Patients

Thirty-two uremic patients on maintenance PD therapy (22 patients on CAPD, and 10 on CCPD) without anatomical heart disease or history of receiving long-term hemodialysis.

Interventions

Home blood pressure (BP) and office BP were measured using the Korotkoff sound technique by sphygmomanometer. ABPM was employed for continuous measurement of BP. Echocardiography was performed for measurement of cardiac parameters and calculation of LVMI.

Main Outcome Measures

Multivariate logistic regression analysis was performed for independent determinant of LVH in PD patients. The differences in clinical and cardiovascular characteristics between CAPD and CCPD patients were compared.

Results

Simple regression analysis showed positive correlations between LVMI and the duration of hypertension, ambulatory nighttime BP/BP load/BP load > 30%, serum phosphate, calcium–phosphate product, ultrafiltration (UF) volume, and percentage of UF volume during the nighttime. A negative correlation was noted between LVMI and dipping. In multiple regression analysis, the duration of hypertension was the only variable linked to LVMI. In multivariate logistic regression analysis, only ambulatory nighttime systolic BP load > 30% had an independent association with LVH. There were correlations between office/home BP and ambulatory 24-hour BP. In addition, CCPD patients had higher LVMI, UF volume during the nighttime, and percentage of UF volume during the nighttime than those of CAPD patients.

Conclusions

In this study, ambulatory nighttime systolic BP load > 30% had an independent association with LVH. Office and home BP measurements were correlated with ABPM in PD patients. The result that CCPD patients had a higher LVMI than CAPD patients may be due to a relative volume overload during the daytime in CCPD patients.
Amadori Albumin and Advanced Glycation End-Product Formation in Peritoneal Dialysis using Icodextrin
Authors: Posthuma Nynke , Ter Wee Pieter M. , Niessen Hans , Donker Ab J.M. , Verbrugh Henri A. , Schalkwijk Casper G.
Published: February 2020

Objective

To study the influence of peritoneal dialysis (PD) solutions on the formation of early glycated products and advanced glycation end-products (AGEs).

Design and Patients

The formation of both Amadori albumin and AGEs in glucose- and icodextrin-based PD fluids was analyzed in vitro and in peritoneal effluents of continuous cyclic peritoneal dialysis (CCPD) patients.

Results

Albumin incubated with glucose-based PD fluids showed a time- and glucose concentration-dependent formation of Amadori albumin and AGEs. Aminoguanidine completely inhibited AGE but not Amadori albumin formation. Albumin incubated in icodextrin resulted in the lowest levels of Amadori albumin and AGE. Amadori albumin levels in effluents of 24 CCPD patients (12 glucose and 12 icodextrin for their daytime dwells) were similar. Dialysate samples collected during a mass transfer area coefficient test in 16 CCPD patients (8 glucose, 8 icodextrin) showed an increase in Amadori albumin formation from baseline ( p < 0.0001), without a difference between the groups. In the total group, there was a positive relationship between duration on PD and dialysate Amadori albumin concentration at 240 minutes ( p = 0.03). The Amadori albumin dialysate-to-plasma (D/P) ratio at 240 minutes was 0.82 ± 0.11, and its clearance amounted to 7.71 ± 1.14 mL/min, while the albumin D/P ratio was 0.010 ± 0.003 and its clearance was 0.089 ± 0.017 mL/min. In a peritoneal biopsy of a CCPD patient, Amadori albumin was observed in the mesothelial layer and the endothelium of the peritoneum.

Conclusions

Using icodextrin-based instead of glucose-based PD fluids can largely reduce the formation of Amadori albumin and AGEs. However, CCPD patients using icodextrin during daytime dwells do not have lower effluent levels of Amadori albumin and AGEs, probably due to the exposure to glucose during their nighttime exchanges. Kinetic studies suggest washout of locally produced Amadori albumin.
Preservation of Residual Renal Function in Dialysis Patients: Effects of Dialysis-Technique–Related Factors
Authors: Lang Susanne M. , Bergner Albrecht , Töpfer Marcel , Schiffl Helmut
Published: February 2020

Objectives

Residual renal function (RRF) is of paramount importance to dialysis adequacy, morbidity, and mortality, particularly for long-term continuous ambulatory peritoneal dialysis (CAPD) patients. Residual renal function seems to be better preserved in patients on CAPD than in hemodialysis (HD) patients. We analyzed RRF in 45 patients with end-stage renal disease (ESRD), commencing either CAPD or HD, to prospectively define the time course of the decline in RRF, and to evaluate dialysis-technique–related factors such as cardiovascular stability and bioincompatibility.

Study Design

Single-center prospective investigation in parallel design with matched pairs.

Materials

Fifteen patients starting CAPD and 15 matched pairs of patients commencing HD were matched according to cause of renal failure and RRF. Hemodialysis patients were assigned to two dialyzer membranes differing markedly in their potential to activate complement and cells (bioincompatibility). Fifteen patients were treated exclusively with the cuprophane membrane (bioincompatible) and the other 15 patients received HD with the high-flux polysulfone membrane (biocompatible).

Measurements

Residual renal function was determined at initiation of dialytic therapy and after 6, 12, and 24 months. Dry weight (by chest x ray and diameter of the vena cava) was closely recorded throughout the study, and the number of hypotensive episodes counted.

Results

Residual renal function declined in both CAPD and HD patients, although this decline was faster in HD patients (2.8 mL/minute after 6 months and 3.7 mL/min after 12 months) than in CAPD patients (0.6 mL/min and 1.4 mL/ min after 6 and 12 months respectively). It declined faster in patients with bioincompatible than with biocompatible HD membranes (3.6 mL/min vs 1.9 mL/min after 6 months). Eleven percent of the HD sessions were complicated by clinically relevant blood pressure reductions, but there were no differences between the two dialyzer membrane groups. None of the CAPD patients had documented hypotensive episodes. None of the study patients suffered severe illness or received nephrotoxic antibiotics or radiocontrast media.

Conclusions

The better preservation of RRF in stable CAPD patients corresponded with greater cardiovascular stability compared to HD patients, independently of the membrane used. Furthermore, there was a significantly higher preservation of RRF in HD patients on polysulfone versus cuprophane membranes, indicating an additional effect of biocompatibility, such as less generation of nephrotoxic substances by the membrane. Thus, starting ESRD patients on HD prior to elective CAPD should be avoided for better preservation of RRF.
Electrophysiology and Glucose Transport of Human Peritoneal Mesothelial Cells: Implications for Peritoneal Dialysis
Authors: Li Fu Keung , To Chi Ho , Leung Jack Kok Hung , Chan Tak Mao , Lai Ka Neng
Published: February 2020

Objective

To elucidate ionic and glucose transport across human peritoneal mesothelium, we utilized an Ussing chamber setup and studied the electrophysiological characteristics and tissue permeabilities of human peritoneal mesothelial cells (HPMC) to l- and d-glucose.

Methods

Human mesothelial cells were grown on polyester filters (snapwell; Costar, Cambridge, MA, U.S.A.) that, upon confluence, were fitted into Ussing chambers. Transmesothelial resistance and resting potential were determined using electro-physiological techniques. Radiolabeled glucose was added to one side of the chamber and the permeabilities determined by serial sampling in the receptive compartment.

Results

The transmesothelial potential and resistance were 0.54 ± 0.07 mV (apical positive) and 20.4 ± 3.2 Ω·cm2 respectively (mean ± SEM, n = 36). The course of overall transfer of d- and l-glucose was examined using l-glucose as a positive diffusion-plus-leak marker. The permeabilities of HPMC to d-glucose were 3.00 ± 0.26 cm/sec (apical-to-basolateral) and 3.25 ± 0.27 cm/sec (basolateral-to-apical) [ n = 6 experiments, p = not significant (NS)], which were not different from those of l-glucose: 3.00 ± 0.30 cm/sec (apical-to-basolateral) and 2.71 ± 0.24 (basolateral-to-apical) ( n = 6 experiments, p = NS).

Conclusions

The transepithelial resistance of HPMC is low and the ionic gradient, although it exists, is small and inconsequential. Passive paracellular flow accounts for the majority of transmesothelial glucose transport. The existence of a large paracellular shunt precludes the mesothelial membrane as a clinically relevant osmotic barrier.
Intraperitoneal Hyaluronan Administration in Conscious Rats: Absorption, Metabolism, and Effects on Peritoneal Fluid Dynamics
Authors: Breborowicz Andrzej , Polubinska Alicja , Pawlaczyk Krzysztof , Kuzlan–Pawlaczyk Malgorzata , Moberly James , Martis Leo , Oreopoulos Dimitrios
Published: February 2020

Background

Hyaluronan (HA) is a major component of interstitial tissue that participates in fluid homeostasis, response to inflammation, and wound healing. Previous studies have shown that intraperitoneal administration of HA can affect peritoneal fluid transport during short peritoneal dialysis exchanges in anesthetized rats. We sought to investigate the effect of high molecular weight HA on peritoneal permeability in conscious rats during dialysis exchanges up to 8 hours in duration. In addition, we sought to investigate the absorption of HA from the peritoneal cavity, its accumulation in peritoneal tissues, and its metabolism in normal and uremic rats.

Methods

Experiments were performed on male Wistar rats infused with 30 mL peritoneal dialysis solution (Dianeal, Baxter Healthcare; Castelbar, Ireland) containing 10 mg/dL HA or with Dianeal alone (control). Peritoneal fluid removal (net ultrafiltration), permeability to glucose, creatinine, and total proteins, and tissue and blood levels of HA were determined in separate groups of rats at 1, 2, 4, 6, and 8 hours after intraperitoneal infusion. Hyaluronan appearance and disappearance from plasma were also studied for 24 hours in separate groups of normal and uremic rats.

Results

Net ultrafiltration was significantly greater (27%) in rats infused with HA at 4, 6, and 8 hours ( p < 0.01) compared to controls. Transperitoneal equilibration of protein was reduced by 27% ( p < 0.001) at 4 hours and by 30% ( p < 0.01) at 8 hours. During the 8-hour exchange, peritoneal clearance of creatinine increased by 27% ( p < 0.01), whereas the clearance of total protein decreased by 27% ( p < 0.005). After 8 hours, 25.7% ± 3.1% of the administered HA was absorbed from the peritoneal cavity, peritoneal tissue HA concentration was increased by 117% ( p < 0.001), and plasma HA levels increased by 435% ( p < 0.001). Plasma HA levels returned to normal within 24 hours after intraperitoneal administration in both healthy and uremic rats.

Conclusions

Hyaluronan added to dialysis fluid is absorbed from the peritoneal cavity and accumulates in peritoneal tissues. Hyaluronan supplementation produces changes in peritoneal permeability, leading to higher net ultrafiltration and peritoneal creatinine clearance, whereas total protein clearance decreases. The HA that is absorbed from the peritoneal cavity appears to be rapidly metabolized in both healthy and uremic rats.
Systemic Lupus Erythematosus and Peritoneal Dialysis: Outcomes and Infectious Complications
Authors: Huang Jenq-Wen , Hung Kuan-Yu , Yen Chung-Jen , Wu Kwan-Dun , Tsai Tun-Jun
Published: February 2020

Objective

Systemic lupus erythematosus (SLE) is the most common secondary glomerulonephritis resulting in end-stage renal disease (ESRD) among young adults in Taiwan. Studies of the infectious complications and outcomes among such SLE patients undergoing peritoneal dialysis (PD) are limited.

Design

A retrospective age- and gender-matched case control study.

Setting

A university teaching hospital.

Patients

There were 23 SLE patients with ESRD receiving PD for more than 3 months during the past 15 years. Another 46 age- and gender-matched non-SLE nondiabetic patients receiving PD were selected as the control group in this study.

Intervention

All patients underwent PD as renal replacement therapy and were regularly followed up at this hospital.

Main Outcome Measures

Technique survival and incidences of exit-site infection (ESI) and peritonitis in these patients.

Results

The SLE patients had a lower predialysis serum albumin than the control group (3.16 ± 0.50 g/dL vs 3.52 ± 0.50 g/dL, p < 0.01). The incidences of exit-site infection (ESI) and peritonitis were higher for SLE patients than for control patients ( p < 0.01 and p < 0.001, respectively). Kaplan–Meier survival analysis indicated that SLE patients had shorter time intervals to first infectious complications, and poorer technique survival. Infection was the major cause of dropout and mortality in the SLE patients. The SLE patients had a reduced chance of receiving a renal transplant. The use of steroids by SLE patients was associated with a higher incidence of peritonitis ( p = 0.04), but association with ESI was insignificant. In a Cox regression model, the underlying SLE was the only risk factor for technique failure and time interval to first infectious complication.

Conclusion

SLE patients undergoing PD are more susceptible to infection than age- and gender-matched non-SLE nondiabetic patients and have poorer technique survival. Systemic lupus erythematosus itself may further compromise the immunity of uremic patients.
Changes in Peritoneal Equilibration Test Values during Long-Term Peritoneal Dialysis in Peritonitis-Free Children
Authors: Yoshino Atsunori , Honda Masataka , Fukuda Masamichi , Araki Yoshinori , Hataya Hiroshi , Sakazume Satoru , Tanaka Yuriko , Kawamura Ken , Murai Takayasu , Kamiyama Yasunori
Published: February 2020

Little is known about the changes in peritoneal equilibration test (PET) values in children on long-term peritoneal dialysis (PD). In the present study, a PET was carried out every 6 months in 39 children (mean age 8.8 ± 5.5 years) undergoing PD for 6 to 85 months (mean 36.9 ± 23.1 months). Patients experiencing peritonitis were excluded. Both D/P creatinine (dialysate-to-plasma ratio of creatinine at 4 hours) and D/D0 glucose (ratio of dialysate glucose at 4 hours’ dwell time to dialysis glucose at 0 dwell time) were measured 195 times in this series of patients. No remarkable change was found for D/P creatinine or D/D0 glucose during the first 24 months of PD but thereafter, D/P creatinine increased gradually and D/D0 glucose decreased gradually. Mean D/P creatinine increased significantly after the first 24 months of PD: from 0.66 ± 0.12 during the first 24 months, to 0.70 ± 0.09 after 25 months and more of PD ( p = 0.0051). Mean D/D0 glucose decreased significantly after 24 months of PD: from 0.42 ± 0.09 during the first 24 months, to 0.38 ± 0.08 after 25 months and more of PD ( p = 0.0015). The most significant change for both D/P creatinine and D/D0 glucose occurred after 24 months of PD. It seems reasonable to consider the mean PET values at 24 months of PD as the standard PET values.
Glucose Degradation Products and Peritoneal Membrane Function
Authors: Witowski Janusz , Bender Thorsten O. , Gahl Gerhard M. , Frei Ulrich , Jörres Achim
Published: February 2020

Background

The bioincompatibility of peritoneal dialysis fluids (PDF) in current use has been partially attributed to the presence of glucose degradation products (GDPs), which are generated during heat sterilization of PDF. Several of the GDPs have been identified and we have recently demonstrated that these GDPs per se may impair the viability and function of human peritoneal mesothelial cells (HPMC) in vitro. It is also possible that GDP-related toxicity is further exacerbated by the milieu of PDF. We review the current literature on GDP and present the results of experiments comparing the impact of heat- and filter-sterilized PDF on the viability and function of HPMC.

Methods

Peritoneal dialysis fluids with low (1.5%) and high (4.25%) glucose concentrations were laboratory prepared according to the standard formula and sterilized either by heat (H-PDF; 121°C, 0.2 MPa, 20 minutes) or filtration (F-PDF; 0.2 μ). The buildup of GDP was confirmed by UV absorbance at 284 nm. Confluent HPMC monolayers were exposed to these solutions mixed 1:1 with standard M199 culture medium. After 24 hours, cell viability was assessed with the MTT assay, and interleukin-1β–stimulated monocyte chemotactic protein-1 (MCP-1) release with specific immunoassay.

Results

Exposure of HPMC to H-PDF resulted in a significant decrease in cell viability, with solutions containing 4.25% glucose being more toxic than 1.5% glucose-based PDF (27.4% ± 3.4% and 53.4% ± 11.0% of control values, respectively). In contrast, viability of HPMC exposed to F-PDF was not different from that of control cells. Moreover, treatment with H-PDF impaired the release of MCP-1 from HPMC to a significantly greater degree compared to F-PDF (17.4% and 24.9% difference for low and high glucose PDF, respectively).

Conclusions

Exposure of HPMC to H-PDF significantly impairs cell viability and the capacity for generating MCP-1 compared to F-PDF. This effect is likely to be mediated by GDPs present in H-PDF but not in F-PDF.
Importance of Blood Pressure and Volume Control in Peritoneal Dialysis Patients
Authors: Lameire Norbert , Van Biesen Wim
Published: February 2020

Objectives

To review the factors that impact control of blood pressure and euvolemia in peritoneal dialysis patients.

Design

Review of the most recent publications on this subject; inclusion of some personal data on the relation between plasma volume and evolution of blood pressure in short-term and long-term peritoneal dialysis patients.

Setting

Peritoneal dialysis program in a university hospital.

Results

The literature on circadian blood pressure and the role of the decreased compliance of the great vessels in uremia is reviewed. Analysis of the long-term evolution of plasma volume in peritoneal dialysis patients in correlation with the evolution of blood pressure indicates a positive correlation in 36 of 46 simultaneous determinations. The treatment of volume overload and hypertension in peritoneal dialysis includes the prescription of loop diuretics, preservation of residual renal function, reduction of dietary salt intake, and prevention and treatment of peritoneal ultrafiltration failure.

Conclusions

A reduction in the great cardiovascular mortality in peritoneal dialysis patients as nowadays observed can only be expected when more attention is paid to better control of hypervolemia and hypertension in these patients.
Monitoring of Long-Term Peritoneal Membrane Function
Authors: Davies Simon J.
Published: February 2020

Objective

Peritoneal membrane function influences dialysis prescription and clinical outcome and may change with time on treatment. Increasingly sophisticated tools, ranging from the peritoneal equilibration test (PET) to the standard permeability analysis (SPA) and personal dialysis capacity (PDC) test, are available to the clinician and clinical researcher. These tests allow assessment of a number of aspects of membrane function, including solute transport rates, ultrafiltration capacity, effective reabsorption, transcellular water transport, and permeability to macromolecules. In considering which tests are of greatest value in monitoring long-term membrane function, two criteria were set: those that result in clinically relevant interpatient differences in achieved ultrafiltration or solute clearances, and those that change with time in treatment.

Study Selection

Clinical validation studies of the PET, SPA, and PDC tests. Studies reporting membrane function using these methods in either long-term (5 years) peritoneal dialysis patients or longitudinal observations (> 2 years).

Data Extraction

Directly from published data. Additional, previously unpublished analysis of data from the Stoke PD Study.

Results

Solute transport is the most important parameter. In addition to predicting patient and technique survival at baseline, there is strong evidence that it can increase with time on treatment. Whereas patients with initially high solute transport drop out early from treatment, those with low transport remain longer on treatment, although, over 5 years, a proportion develop increasing transport rates. Ultrafiltration capacity, while being a composite measure of membrane function, is a useful guide for the clinician. Using the PET (2.27% glucose), a net ultrafiltration capacity of < 200 mL is associated with a 50% chance of achieving less than 1 L daily ultrafiltration at the expense of 1.8 hypertonic (3.86%) exchanges in anuric patients. Using a SPA (3.86% glucose), a net ultrafiltration capacity of < 400 mL indicates ultrafiltration failure. While there is circumstantial evidence that, with time on peritoneal dialysis, loss of transcellular water transport might contribute to ultrafiltration failure, none of the current tests is able to demonstrate this unequivocally. Of the other membrane parameters, evidence that interpatient differences are clinically relevant (permeability to macro-molecules), or that they change significantly with time on treatment (effective reabsorption), is lacking.

Conclusion

A strong case can be made for the regular assessment by clinicians of solute transport and ultrafiltration capacity, a task made simple to achieve using any of the three tools available.
Clinical Benefits and Tolerability of Increased Fill Volumes in Japanese Peritoneal Dialysis Patients
Authors: Fukatsu Atsushi , Komatsu Yasuhiro , Senoh Hachiro , Miyai Hironobu , Tanaka Yoshinori , Oiwa Takafumi , Nakauchi Miyuki , Kasori Ryoko , Takahashi Sumiko , Kawahara Hirohisa , Mayber Nicky , Yost Lawrence E. , Ogrinc Francis G. , Mujais Salim
Published: February 2020

Background

Increasing fill volume is an effective means of improving clearances in patients on peritoneal dialysis (PD). Since Japanese PD patients are physically smaller than their Western counterparts, there is some concern that PD patients in Japan may be unable to tolerate larger fill volumes.

Objective

To determine patient tolerance and changes in solute clearance and net ultrafiltration resulting from increased fill volumes in Japanese patients on PD.

Design

Prospective double-blind study, randomizing patients to three different fill volumes (2.5% dextrose solution: 1.5 L, 2.0 L, or 2.5 L) administered in random order on three different occasions separated by 1 week.

Results

Twenty-one patients with a mean age of 55.4 ± 2.1 years and a mean body surface area of 1.66 ± 0.03 m2 were studied. On a scale of 0 to 10, patients’ mean discomfort scores were 2.14 ± 0.59, 3.48 ± 0.54, and 3.81 ± 0.63 ( p = 0.047) at the end of the 1.5-L, 2.0-L, and 2.5-L dwells, respectively. There were no reports of cramps or shortness of breath with any fill volume. Patients were able to correctly guess the actual fill volume for only 34 of the 63 total exchanges (54.0%). Increasing fill volume resulted in an incremental improvement in peritoneal creatinine clearance, from 3.74 ± 0.16 to 4.49 ± 0.21 ( p < 0.001, 2.0 L vs 1.5 L) to 5.12 ± 0.20 mL/minute ( p < 0.001, 2.5 L vs 2.0 L) for 1.5-L, 2.0-L, and 2.5-L dwells, respectively. Peritoneal urea clearance also increased significantly, from 5.65 ± 0.13 to 7.04 ± 0.17 ( p < 0.001, 2.0 L vs 1.5 L) and 8.16 ± 0.29 mL/minute ( p < 0.001, 2.5 L vs 2.0 L), with incremental increases in fill volume. Similarly, net ultrafiltration in a 4-hour dwell increased significantly with fill volume, from 255.24 ± 24 mL with 1.5 L, to 356 ± 24 ( p < 0.004, 2.0 L vs 1.5 L) and 392 ± 29 mL ( p < 0.086, 2.5 L vs 2.0 L) in patients receiving 2.0 L and 2.5 L, respectively.

Conclusion

Increasing the fill volume results in improvement in solute clearance and net ultrafiltration in Japanese PD patients, with minimal increase in patient discomfort. A large percentage of patients were unable to identify the actual fill volume.
Expression of Cancer Antigen 125 by Peritoneal Mesothelial Cells is Not Influenced by Duration of Peritoneal Dialysis
Authors: Sanusi Abubakr A. , Zweers Machteld M. , Weening Jan J. , De Waart Dirk R. , Struijk Dirk G. , Krediet Raymond T.
Published: February 2020

Objective

To investigate the presence of cancer antigen 125 (CA125) on mesothelial cells in the effluent of peritoneal dialysis (PD) patients and to analyze the effect of duration of PD on the number of mesothelial cells in peritoneal effluent, the number of CA125-positive cells, and dialysate CA125 concentration.

Design

A cross-sectional study in which long-dwell peritoneal effluents were investigated for mesothelial cells and CA125.

Setting

A university hospital population of chronic PD patients.

Patients

33 stable PD patients who were free of peritonitis during the investigation and during the 4 weeks prior to the study.

Methods

Examination of cytospin preparations of peritoneal effluent stained with May-Grünwald Giemsa, and also with an immunocytochemical double-staining method consisting of anticalretinin (pan-mesothelial cell marker) and OC125.

Results

A close relationship was present between the numbers of mesothelial cells counted with the two staining methods ( r = 0.998, p < 0.001). On average, 92% of mesothelial cells were positive for CA125, ranging between 75% and 100% in 80% of the patients. Correlations were found between the effluent CA125 concentration and the total number of mesothelial cells ( r = 0.64, p < 0.001), and also the number of CA125-positive cells ( r = 0.66, p < 0.001). A negative effect of time was seen on the effluent CA125 concentration, the total number of mesothelial cells, and the number of CA125-positive mesothelial cells. However, no effect of time was present on the percentage CA125-positive cells.

Conclusions

On average, 92% of mesothelial cells in peritoneal effluent are positive for CA125. This figure is not dependent on the duration of PD. Long-term PD is associated with low dialysate CA125 concentrations, a low number of mesothelial cells, and a low number of CA125-positive mesothelial cells in effluent. These results support the hypothesis that dialysate CA125 can be used as a marker of mesothelial cell mass in stable PD patients.