HLA class I depletion by citric acid, and irradiation of apheresis platelets for transfusion of refractory patients.

BACKGROUND: Patients can form antibodies to foreign human leukocyte antigen (HLA) Class I antigens after exposure to allogeneic cells. These anti-HLA class I antibodies can bind transfused platelets (PLTs) and mediate their destruction, thus leading to PLT refractoriness. Patients with PLT refractoriness need HLA-matched PLTs, which require expensive HLA typing of donors, antibody analyses of patient sera and/or crossmatching. An alternative approach is to reduce PLT HLA Class I expression using a brief incubation in citric acid on ice at low pH. METHODS AND MATERIALS: Apheresis PLT concentrates were depleted of HLA Class I complexes by 5 minutes incubation in ice-cold citric acid, at pH 3.0. Surface expression of HLA Class I complexes, CD62P, CD63, phosphatidylserine, and complement factor C3c was analyzed by flow cytometry. PLT functionality was tested by thromboelastography (TEG). RESULTS: Acid treatment reduced the expression of HLA Class I complexes by 71% and potential for C3c binding by 11.5-fold compared to untreated PLTs. Acid-treated PLTs were significantly more activated than untreated PLTs, but irrespective of this increase in steady-state activation, CD62P and CD63 were strongly upregulated on both acid-treated and untreated PLTs after stimulation with thrombin receptor agonist peptide. Acid treatment did not induce apoptosis over time. X-ray irradiation did not significantly influence the expression of HLA Class I complexes, CD62P, CD63, and TEG variables on acid treated PLTs. CONCLUSION: The relatively simple acid stripping method can be used with irradiated apheresis PLTs and may prevent transfusion-associated HLA sensitization and overcome PLT refractoriness.

[How to implement a complete apheresis program within a hemodialysis unit]. / Comment mettre en place un plateau technique d'aphérèses.

Many apheresis techniques can be performed in a blood-bank facility or a hemodialysis (HD) facility. However, it makes sense to perform apheresis in a hemodialysis facility as apheresis involves extra-corporeal circuits and because HD can be performed at the same time as apheresis (tandem procedure). Apheresis techniques comprise therapeutic plasma exchange, double-filtration plasmapheresis, and its derivative (rheopheresis and LDL-apheresis), and immunoadsorption (specific and semi-specific). We have setup an apheresis platform in our hospital that fulfills health recommendations. This process has involved financial investment and significant human resources, and has enabled us to network with different specialties (neurology, hematology, vascular medicine). We have setup protocols according to the type of pathology to be treated by apheresis, and to monitor clinical and biological data for each apheresis session. The main side effects of apheresis are a fall in blood pressure when a session is initiated, an increase in fluid overload, hypocalcemia, and the loss of some essential plasmatic factors. However, these side-effects are easily identified and can be properly managed in real time. Within two-years, we have performed 1845 apheresis sessions (134 patients). Of these, 66 received apheresis before and/or after kidney transplantation for ABO and/or HLA incompatibility (desensitization), for humoral rejection, or in the setting of relapsing focal-segmental glomerulosclerosis. Our patients' outcomes have been similar to those reported in the literature. The other 68 patients had various conditions. Because our program is now well-established, we are currently forming a specialist center to train physicians and nurses in the various apheresis techniques/procedures.

[Comparison of citrate 4% and heparin as tunneled-catheters-locking solution in chronic hemodialysis]. / Comparaison des verrous de cathéters tunnellisés par citrate 4 % et héparine en hémodialyse chronique.

INTRODUCTION: Citrate 4% is an alternative to heparin as catheter-locking solution in chronic hemodialysis patients. We compared catheter dysfunction episodes, dialysis adequacy, plasminogen-tissular activators use and costs according to catheter-locking solution in our centre. METHODS: Prospective, monocentric, cohort study (NephroCare Tassin-Charcot) on 49 prevalent patients in chronic hemodialysis. Two main groups were formed according to the prescription of catheter-locking solution at the beginning of the study (03/02/2016) and followed until 05/10/2016: heparin (n=26) and citrate (n=22). RESULTS: The number of diabetic patients was higher in the citrate group (12/22) than in the heparin one (5/26; P=0.025). The 2 groups were comparable for the other studied variables. We didn't observe any difference in terms of catheter-dysfunction (4.23 versus 4.14% in heparin and citrate groups, respectively; P=1.0) and dialysis adequacy. The prescription of citrate was associated with lower TPA uses (1/604 versus 14/946; P=0.022) and lower costs (1.42 € for one session versus 2.94 €). CONCLUSION: Administration of citrate 4% as a catheter-locking solution is not inferior to heparin in terms of catheter-dysfunction episodes, is associated with similar dialysis adequacy results, lower plasminogen-tissular activators uses and reduced costs in chronic prevalent hemodialysed patients.

Exploratory study of acid-forming potential of commercial cheeses: impact of cheese type.

Due to their composition, cheeses are suspected to induce an acid load to the body. To better understand this nutritional feature, the acid-forming potential of five cheeses from different cheese-making technologies and two milk was evaluated on the basis of their potential renal acid load (PRAL) index (considering protein, P, Cl, Na, K, Mg and Ca contents) and organic anions contents. PRAL index ranged from -0.8 mEq/100 g edible portion for fresh cheese to 25.3 mEq/100 g for hard cheese Cantal and 28 mEq/100 g for blue-veined cheese Fourme d'Ambert. PRAL values were greatly subjected to interbatch fluctuations. This work emphasized a great imbalance between acidifying elements of PRAL calculation (Cl, P and proteins elements) and alkalinizing ones (Na and Ca). Particularly, Cl followed by P elements had a strong impact on the PRAL value. Hard cheeses were rich in lactate, thus, might be less acidifying than suspected by their PRAL values only.

Transition From Heparin to Citrate Anticoagulation for Continuous Renal Replacement Therapy: Safety, Efficiency, and Cost.

Regional citrate anticoagulation (RCA) for continuous renal replacement therapy (CRRT) has recently been recommended as first-line over heparin. Evidence suggests that RCA prolongs filter life and may reduce bleeding risk, but there is little research on the benefits to dialysis dose delivery or cost, or the effectiveness of transitioning to RCA first-line. The aim of the present study was to assess the effect on dialysis delivery, cost and safety when transitioning from systemic heparin to RCA for first-line anticoagulation for CRRT. A single-center, retrospective observational study was conducted from 2006 to 2012, during which a transition from heparin to a simplified RCA protocol occurred. Demographic and dialysis data, pathology results and costs were obtained. Data were analyzed for both heparin and RCA, and for before and after the transition. 166 patients had 992 dialysis days (heparin 334 vs. RCA 658); demographics were well matched; RCA used less filters per day (P = 0.03), had more days when prescribed dialysis was achieved (85% vs. 60%, P < 0.001), and less filter "down-time" per day (2.4 vs. 6.1 h, P = 0.02). RCA was estimated to cost AU$487 per day, compared to heparin at $479 per day. When the data were analyzed, comparing before and after the transition, these results remained statistically significant. There was no statistical difference in clinical safety events. Transition to first-line RCA was safe, provided more time on filter and consumed less filter circuits using a simple and user friendly protocol. The adjusted cost difference appears negligible.

In vitro assessment of artificial saliva formulations on initial enamel erosion remineralization.

OBJECTIVES: Various formulations of artificial saliva are present in the literature and little guidance is available on the standardization of type of saliva for use in in vitro protocols for erosive studies. The aim of this study was to evaluate the remineralizing capacity of different formulations of artificial saliva on initial enamel erosive lesion. METHODS: Bovine enamel blocks were subjected to short-term acidic exposure by immersion in citric acid 0.05 M (pH 2.5) for 15s, resulting in surface softening without tissue loss. Then 90 selected eroded enamel blocks were randomly and equally divided into 6 groups according to saliva formulation (n=15): Saliva 1 (contain mucin); Saliva 2 (Saliva 1 without mucin); Saliva 3; Saliva 4; Saliva 5 (contain sodium carboxymethyl cellulose) and control (C) (deionized water). After demineralization enamel blocks were subjected to remineralization by immersion in the saliva's formulations for 2h. Enamel remineralization was measured by superficial hardness test (% superficial hardness change). The data were tested using ANOVA and Tukey's test (p<0.05). RESULTS: All the tested formulations of artificial saliva resulted in significantly higher enamel remineralization compared to control (p<0.001). Saliva 3 showed higher percentage of enamel remineralization than Saliva 5 (p<0.05). CONCLUSIONS: Besides the variety of artificial saliva for erosion in vitro protocols, all the formulations tested were able to partially remineralize initial erosive lesions.

Pico-Salax versus polyethylene glycol for bowel cleanout before colonoscopy in children: a randomized controlled trial.

BACKGROUND AND STUDY AIMS: Comparison of bowel preparation for colonoscopy in children with either Pico-Salax (sodium picosulphate with magnesium citrate) or polyethylene glycol with electrolyte solution (PEG-ELS). PATIENTS AND METHODS: In this investigator-blinded, randomized controlled trial, 83 children (12.5 +/- 3.1 years) requiring elective colonoscopy at a referral hospital were randomly allocated to Pico-Salax (n = 43) or PEG-ELS (n = 40), and an intention-to treat analysis was applied. Pico-Salax was administered in two doses, one the evening before and one on the morning of the procedure. PEG-ELS was administered over 4 hours. Efficacy was scored using the Ottawa scale and other constructs. Tolerability and toxicity were measured by patient and nursing questionnaires and serum biochemistry. RESULTS: 35 of Pico-Salax patients (81 %) were satisfied or very satisfied with the cleanout, compared with 19 (48 %) in the PEG-ELS group (P = 0.001). No differences were found in bowel cleanout effectiveness, as judged by the Ottawa score (P = 0.24), completion rates (P = 0.69), colonoscopy duration (P = 0.59), need for enemas (P = 0.25), or physician's global impression (P = 0.7). Except for one case of mild dehydration in the Pico-Salax group, no clinically significant adverse events were recorded. Serum biochemistry results were similar between groups except for more hypermagnesemia associated with Pico-Salax and hypokalemia with PEG-ELS; neither was clinically significant. CONCLUSION: Children tolerate Pico-Salax better than PEG-ELS for bowel cleanout before colonoscopy. This study did not demonstrate superiority of effectiveness or safety for either regimen.

Comparison of calcium analysis, longitudinal microradiography and profilometry for the quantitative assessment of erosion in dentine.

Erosion of dentine causes mineral dissolution, while the organic compounds remain at the surface. Therefore, a determination of tissue loss is complicated. Established quantitative methods for the evaluation of enamel have also been used for dentine, but the suitability of these techniques in this field has not been systematically determined. Therefore, this study aimed to compare longitudinal microradiography (LMR), contacting (cPM) and non-contacting profilometry (ncPM), and analysis of dissolved calcium (Ca analysis) in the erosion solution. Results are discussed in the light of the histology of dentine erosion. Erosion was performed with 0.05 M citric acid (pH 2.5) for 30, 60, 90 or 120 min, and erosive loss was determined by each method. LMR, cPM and ncPM were performed before and after collagenase digestion of the demineralised organic surface layer, with an emphasis on moisture control. Scanning electron microscopy was performed on randomly selected specimens. All measurements were converted into micrometres. Profilometry was not suitable to adequately quantify mineral loss prior to collagenase digestion. After 120 min of erosion, values of 5.4 +/- 1.9 microm (ncPM) and 27.8 +/- 4.6 microm (cPM) were determined. Ca analysis revealed a mineral loss of 55.4 +/- 11.5 microm. The values for profilometry after matrix digestion were 43.0 +/- 5.5 microm (ncPM) and 46.9 +/- 6.2 (cPM). Relative and proportional biases were detected for all method comparisons. The mineral loss values were below the detection limit for LMR. The study revealed gross differences between methods, particularly when demineralised organic surface tissue was present. These results indicate that the choice of method is critical and depends on the parameter under study.

Topographic and radiographic profile assessment of dental erosion. Part II: effect of citrus fruit juices on human dentition.

This study sought to monitor changes in the topography, morphology, and radiographic profiles of human permanent teeth that had been exposed to citrus fruit juices. The effect of long-term exposure was monitored for a prolonged duration of 20 weeks according to set criteria. Topographic and morphologic changes were observed at weekly intervals following challenge by test fluids (orange, lemon, and grapefruit juices) and compared with control fluids (acetic acid and water). The qualitative changes in the specimens' topography and the morphology of citrus fruit juices and control fluids are described as a function of time, in specific details. The digitized radiographic images obtained at four-week intervals were analyzed and the changes were assessed. The results indicated that orange juice specimens demonstrated the mildest changes, while lemon juice specimens displayed the most severe damage to the coronal segments of the teeth. This damage manifested as loss of cusp height, cervical enamel, and coronal radius, as well as reduction of enamel cap height. Of the tested and control fluids, lemon juice displayed the most eros ion, followed by acetic acid, grapefruit juice, orange juice, and water, which had no effect. Continued immersion in the four acidic fluids led to varying degrees of enamel loss progression.

Assessment of corrected QT interval in sickle-cell disease patients who undergo erythroapheresis.

Extension of the QT interval is characterized by syncope and cardiac arrest and often occurs in association with medical therapies and procedures. Whether erythroapheresis (EPH) could influence the QT interval duration in patients with sickle cell disease (SCD) is not known. We aimed to investigate the effects of EPH on the heart rate-corrected QT (QTc) interval. The study included 25 patients with SCD who underwent 34 EPH procedures. Two independent observers measured QTc interval duration from electrocardiograms performed continuously for 3 min at three different points during the EPH procedures (prior to EPH, after completion of 50% EPH and 15 min after EPH). Multiple regression analysis was used to determine if the ionized plasma calcium, the level of plasma magnesium, citrate infusion rate and painful crisis significantly contributed to the QTc interval. There was a non-significant trend (P = 0.184) towards increased QTc in sickle cell patients during EPH compared with pre-EPH values. QTc prolongation (>440 ms) occurred in 72% of the procedures. Fifty percent QTc values returned to baseline after the procedure. The independent variables were not significantly associated with QTc interval. Exchange procedures can induce QTc prolongation in patients with SCD.

Topographic and radiographic profile assessment of dental erosion--Part I: Effect of acidulated carbonated beverages on human dentition.

Evidence-based case reports and epidemiologic surveys have indicated an association between dental erosion and high consumption of acidulated carbonated beverages (ACBs). This study sought to monitor the effect of exposure to ACBs on the topography and geometrical profile of disassociated human dentition. Two representatives of ACBs, caramelized (ACCB) and non-caramelized (AN-CCB), were evaluated along with control liquids. Following exposure to the fluids, qualitative assessment of topographic changes and quantitative analysis of digitized serial radiographic tracings were performed at four-week intervals for 20 weeks. Within the controlled perimeters of this in vitro test, the erosive effects of ACBs were closely similar but were lower than those caused by acetic acid (control fluid). These effects were indicated by changes in enamel topography (such as color, translucency, texture, and integrity) as well as reduction in specimen profile parameters. This amounted to an average weekly reduction in cusp tip height, a loss of cervical enamel, a reduction of enamel cap height, and reduction of crown radius for the ACBs and acetic acid.

Comparison of calcium/phosphorus analysis, longitudinal microradiography and profilometry for the quantitative assessment of erosive demineralisation.

The study is a comparison of methods for the quantitative measurement of erosive mineral loss including longitudinal microradiography (LMR), profilometry (PM), and analysis of calcium (CA) and phosphorus (PA) in the erosion solution. Polished human enamel samples were taped, covered with nail varnish and the edges of the resulting enamel window marked with drilled holes as a reference. All samples were subjected to baseline LMR. Sixty samples each were eroded with citric acid (0.05 M; pH 2.3; 10 ml per sample) for 30, 60, 90, or 120 min. Erosive loss of each sample was estimated by the four methods. All methods revealed a linear erosive loss over time and showed good linear correlation. Values calculated from PM and LMR were both approximately 20% lower than those from CA and PA. After 30 min erosion, LMR showed no significant correlation with the other three methods. With LMR, erosive loss below 20 microm should be interpreted with care.