scholarly journals Intraperitoneal pressure: Stability over time and validation of Durand’s measurement method

2020 ◽  
pp. 089686082097312
Author(s):  
Alicia Sobrino-Pérez ◽  
Alfonso Pérez-Escudero ◽  
Lucila Fernández-Arroyo ◽  
Ana Dorado-García ◽  
Berta Martín-Alcón ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Venous Pressure ◽  
Relevant Parameter ◽  
Pressure System ◽  
Intraperitoneal Pressure ◽  
In Vitro Measurements ◽  
Long Timescales ◽  
Over Time

Intraperitoneal pressure (IPP) is gaining consideration as a relevant parameter of peritoneal dialysis (PD) in adults, although many of its aspects are still pending clarification. We address here its stability over time and the validity of the usual method of clinical measurement, as proposed by Durand in 1992 but never specifically validated. We performed this validation by comparing Durand’s method and direct measurements with a central venous pressure system. We performed a total of 250 measurement pairs in 50 patients with different intraperitoneal volumes plus in-vitro measurements with a simulated peritoneum. Absolute differences between the two systems in vivo were 0.87 ± 0.91 cmH2O (range 0–5 cmH2O); only 6.4% of them were ≥3 cmH2O. In vitro results for both methods were identical. We also compared IPP measurements in the same patient separated by 1–4 h (514 measurement pairs in 136 patients), 1 week (92 pairs in 92 patients), and 2 years (34 pairs in 17 patients). Net differences of measurements separated by hours or 1 week were close to 0 cmH2O, with oscillations of 1.5 cmH2O in hours and 2.3 cmH2O in 1 week. IPP measured 2 years apart presented a net decrease of 2.5 ± 4.9 cmH2O, without correlation with body mass index changes or any other usual parameter of PD. In hours, 7% of IPP differences were >3 cmH2O, 22% in 1 week, and 50% in 2 years. In conclusion, Durand’s method is precise enough to measure IPP in peritoneal dialysis. This parameter is not stable over long timescales, so it is necessary to use recent measurements.

The Development of Homologous (Canine/Anti-Canine) Antibodies in Dogs with Haemophilia A (Factor VIII Deficiency): A Ten-Year Longitudinal Study

1993 ◽  
Vol 69 (01) ◽  
pp. 021-024 ◽  
Author(s):  
Shawn Tinlin ◽  
Sandra Webster ◽  
Alan R Giles
Keyword(s):  
Factor Viii ◽  
Canine Model ◽  
Significant Inhibition ◽  
Human Condition ◽  
Haemophilia A ◽  
Variable Expression ◽  
The Family ◽  
Over Time

SummaryThe development of inhibitors to factor VIII in patients with haemophilia A remains as a serious complication of replacement therapy. An apparently analogous condition has been described in a canine model of haemophilia A (Giles et al., Blood 1984; 63:451). These animals and their relatives have now been followed for 10 years. The observation that the propensity for inhibitor development was not related to the ancestral factor VIII gene has been confirmed by the demonstration of vertical transmission through three generations of the segment of the family related to a normal (non-carrier) female that was introduced for breeding purposes. Haemophilic animals unrelated to this animal have not developed functionally significant factor VIII inhibitors despite intensive factor VIII replacement. Two animals have shown occasional laboratory evidence of factor VIII inhibition but this has not been translated into clinical significant inhibition in vivo as assessed by clinical response and F.VIII recovery and survival characteristics. Substantial heterogeneity of inhibitor expression both in vitro and in vivo has been observed between animals and in individual animals over time. Spontaneous loss of inhibitors has been observed without any therapies designed to induce tolerance, etc., being instituted. There is also phenotypic evidence of polyclonality of the immune response with variable expression over time in a given animal. These observations may have relevance to the human condition both in determining the pathogenetic factors involved in this condition and in highlighting the heterogeneity of its expression which suggests the need for caution in the interpretation of the outcome of interventions designed to modulate inhibitor activity.

Abstract 5402: Two Photon Microscopy Measurements Of Sub-epicardial Sarcomere Length In Perfused Rat Hearts

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Patrizia Camelliti ◽  
Gil Bub ◽  
Daniel J Stuckey ◽  
Christian Bollensdorff ◽  
Damian J Tyler ◽  
...  
Keyword(s):  
Sarcomere Length ◽  
Left Ventricular ◽  
Model Systems ◽  
Future Research ◽  
Fundamental Parameter ◽  
Rat Hearts ◽  
Perfused Hearts ◽  
Over Time

Sarcomere length (SL) is a fundamental parameter underlying the Frank Starling relation in the heart, as it offers an absolute representation of myocardial stretch. Previous studies addressed the Frank Starling relation by measuring SL in isolated myocytes or muscle strips. Here, we report first data obtained using a novel technique to measure sub-epicardial SL in perfused hearts. Rat hearts were Langendorff perfused (normal Tyrode solution) at a constant pressure of 90mmHg, labeled with the fluorescent membrane marker di-4-ANEPPS, and then arrested with high-K + Tyrode for either 2-photon microscopy (n=4) or MRI (n=4). Image analysis software was developed to extract SL at the cell level from >1,400 2-photon images (Fig 1 ) and correct for cell angle. SL increased by 10±2 % between 30 and 80 min of perfusion (1.98±0.04 to 2.17±0.03 μm; p<0.05; Fig 1 ). Measurements of left ventricular myocardial volume (LVMV) were made in vivo and in perfused hearts using 3D MRI. LVMV increased by 24±7% from in vivo to 30 min of perfusion, and by 11±3 % between 30 and 90 min (539±35; 664±44; 737±49 mm 3 , respectively; p<0.05; Fig 1 ). We show that SL can be measured in isolated perfused hearts. The method allowed monitoring of changes in SL over time, and showed that SL and LVMV increase to a similar extent during 30–80 min perfusion with crystalloid solution, probably due to tissue oedema. This result, together with the increase in LVMV during the first 30 min, highlights the pronounced differences between in vivo , in situ , and in vitro model systems for studies of cardiac physiology and mechanics. Future research will compare changes in SL in healthy hearts and disease models involving contractile dysfunction. Figure 1: Left: 2-photon microscopy image of di-4-ANEPPS labeled myocardium. Right: SL and LVMV changes over time.

scholarly journals Time-Dependent Reduction of Calcium Oscillations in Adipose-Derived Stem Cells Differentiating towards Adipogenic and Osteogenic Lineage

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1400
Author(s):  
Enrico C. Torre ◽  
Mesude Bicer ◽  
Graeme S. Cottrell ◽  
Darius Widera ◽  
Francesco Tamagnini
Keyword(s):  
Stem Cells ◽  
Osteogenic Differentiation ◽  
Adipogenic Differentiation ◽  
Specific Treatment ◽  
Stem Cell Differentiation ◽  
Calcium Oscillations ◽  
Multipotent Stem Cells ◽  
Over Time

Adipose-derived mesenchymal stromal cells (ASCs) are multipotent stem cells which can differentiate into various cell types, including osteocytes and adipocytes. Due to their ease of harvesting, multipotency, and low tumorigenicity, they are a prime candidate for the development of novel interventional approaches in regenerative medicine. ASCs exhibit slow, spontaneous Ca2+ oscillations and the manipulation of Ca2+ signalling via electrical stimulation was proposed as a potential route for promoting their differentiation in vivo. However, the effects of differentiation-inducing treatments on spontaneous Ca2+ oscillations in ASCs are not yet fully characterised. In this study, we used 2-photon live Ca2+ imaging to assess the fraction of cells showing spontaneous oscillations and the frequency of the oscillation (measured as interpeak interval—IPI) in ASCs undergoing osteogenic or adipogenic differentiation, using undifferentiated ASCs as controls. The measurements were carried out at 7, 14, and 21 days in vitro (DIV) to assess the effect of time in culture on Ca2+ dynamics. We observed that both time and differentiation treatment are important factors associated with a reduced fraction of cells showing Ca2+ oscillations, paralleled by increased IPI times, in comparison with untreated ASCs. Both adipogenic and osteogenic differentiation resulted in a reduction in Ca2+ dynamics, such as the fraction of cells showing intracellular Ca2+ oscillations and their frequency. Adipogenic differentiation was associated with a more pronounced reduction of Ca2+ dynamics compared to cells differentiating towards the osteogenic fate. Changes in Ca2+ associated oscillations with a specific treatment had already occurred at 7 DIV. Finally, we observed a reduction in Ca2+ dynamics over time in untreated ASCs. These data suggest that adipogenic and osteogenic differentiation cell fates are associated with specific changes in spontaneous Ca2+ dynamics over time. While this observation is interesting and provides useful information to understand the functional correlates of stem cell differentiation, further studies are required to clarify the molecular and mechanistic correlates of these changes. This will allow us to better understand the causal relationship between Ca2+ dynamics and differentiation, potentially leading to the development of novel, more effective interventions for both bone regeneration and control of adipose growth.

Correlation of in vivo and in vitro measurements of sun protection factor

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
M.-T. Sheu ◽  
C.-W. Lin ◽  
M.-C. Huang ◽  
C.-H. Shen ◽  
H.-O. Ho
Keyword(s):  
Sun Protection ◽  
Protection Factor ◽  
In Vitro Measurements ◽  
Sun Protection Factor

scholarly journals Advances in Photoacoustic Noninvasive Glucose Testing

1999 ◽  
Vol 45 (9) ◽  
pp. 1587-1595 ◽  
Author(s):  
Hugh A MacKenzie ◽  
Helen S Ashton ◽  
Stephen Spiers ◽  
Yaochun Shen ◽  
Scott S Freeborn ◽  
...  
Keyword(s):  
Glucose Measurement ◽  
Oral Glucose ◽  
Physiological Factors ◽  
Glucose Testing ◽  
In Vivo Experiments ◽  
In Vitro Measurements ◽  
Clinical Measurements ◽  
Blood Analytes

Abstract We report here on in vitro and in vivo experiments that are intended to explore the feasibility of photoacoustic spectroscopy as a tool for the noninvasive measurement of blood glucose. The in vivo results from oral glucose tests on eight subjects showed good correlation with clinical measurements but indicated that physiological factors and person-to-person variability are important. In vitro measurements showed that the sensitivity of the glucose measurement is unaffected by the presence of common blood analytes but that there can be substantial shifts in baseline values. The results indicate the need for spectroscopic data to develop algorithms for the detection of glucose in the presence of other analytes.

Pre-Clinical Biocompatibility Testing of Peritoneal Dialysis Solutions

2000 ◽  
Vol 20 (5_suppl) ◽  
pp. 5-9 ◽  
Author(s):  
C.J. Holmes
Keyword(s):  
Peritoneal Dialysis ◽  
Screening Program ◽  
Ex Vivo ◽  
Biological Response ◽  
Cell Types ◽  
Hierarchical Level ◽  
Clinical Phase ◽  
Biocompatibility Testing

Pre-clinical biocompatibility testing of peritoneal dialysis (PD) solutions has become an integral part of new solution development. The construction of a pre-clinical screening program for solution biocompatibility should take a hierarchical approach, starting with in vitro cell viability and function assays. The selection of cell types and assay systems for the in vitro studies should be broad enough to permit a balanced interpretation. Whenever possible, animal models are recommended for the next hierarchical level of testing, followed by human ex vivo study designs. Designs of the latter sort provide evidence that a new solution formulation is exerting an altered biological response in vivo; the response is not purely an in vitro artifact or restricted to a given animal species. This article discusses the various approaches available for biocompatibility testing during the pre-clinical phase of solution development, with an emphasis on the advantages and drawbacks of each method.

scholarly journals P1238EVALUATION OF AN IN VITRO CO-CULTURE MODEL FOR TESTING EFFECTS OF CYTOPROTECTIVE ADDITIVES IN PERITONEAL DIALYSIS FLUIDS ON CARDIOVASCULAR OUTCOME

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Juan Manuel Sacnun ◽  
Rebecca Herzog ◽  
Maria Bartosova ◽  
Claus Schmitt ◽  
Klaus Kratochwill
Keyword(s):  
Endothelial Cells ◽  
Cell Death ◽  
Peritoneal Dialysis ◽  
Cardiovascular Risk ◽  
Cell Damage ◽  
Peritoneal Membrane ◽  
Cytoskeleton Reorganization ◽  
Harmful Effects

Abstract Background and Aims The composition of all currently available peritoneal dialysis (PD) fluids triggers morphological and functional changes in the peritoneal membrane. Periodic exposure leads to vasculopathy, hypervascularization, and diabetes-like damage of vessels, eventually leading to failure of the technique. Patients undergoing dialysis generally, have a high risk of cardiovascular events. It is currently unclear if there is a mechanistic link between peritoneal membrane failure and cardiovascular risk. In vitro and in vivo studies have shown that cytoprotective additives (e.g. dipeptide alanyl-glutamine (AlaGln) or kinase inhibitor lithium chloride (LiCl)) to PDF reduce peritoneal damage. Here, we developed an experimental model for investigating effects of these cytoprotective additives in PDF in the cardiovascular context. Method For modelling the peritoneal membrane in vitro, mesothelial and endothelial cells were co-cultured in transwell plates. Mesothelial cells were grown in the upper compartment and primary human umbilical vein endothelial cells (HUVEc) or primary microvascular cells were grown in the lower compartment. PDF with or without cytoprotective compounds, was added to the upper compartment to only expose mesothelial cells directly to different dilutions of the fluid. Effects on cell damage was assessed by quantification of lactate-dehydrogenase (LDH) release and live-dead staining of cells. Proteome profiles were analysed for both cell-types separately and in combination using two-dimensional difference gel electrophoresis (2D-DiGE) and liquid chromatography coupled to mass spectrometry (LC-MS). In vitro findings were related to PD-induced arteriolar changes based on abundance profiles of micro-dissected omental arterioles of children treated with conventional PD-fluids and age-matched controls with normal renal function. Results Marked cellular injury of HUVEc after PD-fluid exposure was associated with a molecular landscape of the enriched biological process clusters ‘glucose catabolic process’, ‘cell redox homeostasis’, ‘RNA metabolic process’, ‘protein folding’, ‘regulation of cell death’, and ‘actin cytoskeleton reorganization’ that characterize PD-fluid cytotoxicity and counteracting cellular repair process respectively. PDF-induced cell damage was reduced by AlaGln and LiCl both in mesothelial and endothelial cells. Proteome analysis revealed perturbation of major cellular processes including regulation of cell death and cytoskeleton reorganization. Selected markers of angiogenesis, oxidative stress, cell junctions and transdifferentiation were counter-regulated by the additives. Co-cultured cells yielded differently regulated pathways following PDF exposure compared to separate culture. Comparison to human arterioles confirmed overlapping protein regulation between endothelial cells in vitro and in vivo, proving harmful effects of PD-fluids on endothelial cells leading to drastic changes of the cellular process landscape. Conclusion In summary, this study shows harmful effects of PD-fluids also effecting endothelial cells and elucidates potential mechanisms by which cytoprotective additives may counteract the signalling axis between local peritoneal damage and systemic vasculopathy. An in vitro co-culture system may be an attractive approach to simulate the peritoneal membrane for testing direct and indirect effects of cytoprotective additives in PDF. When cultured and stressed in close proximity cells may respond differently. Characterisation of PD-induced perturbations will allow identifying molecular mechanisms linking the peritoneal and cardiovascular context, offering therapeutic targets to reduce current limitations of PD and ultimately decreasing cardiovascular risk of dialysis patients.

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