Pre-Emptive Use of Rituximab in Epstein-Barr Virus Reactivation: Incidence, Predictive Factors, Monitoring, and Outcomes.

Post-transplant lymphoproliferative disease (PTLD) is a fatal complication of hematopoietic cell transplantation (HCT) associated with the Epstein-Barr virus (EBV). Multiple factors such as transplant type, graft-versus-host disease (GVHD), human leukocyte antigens (HLA) mismatch, patient age, and T-lymphocyte-depleting treatments increase the risk of PTLD. EBV reactivation in hematopoietic cell transplant recipients is monitored through periodic quantitative polymerase chain reaction (Q-PCR) tests. However, substantial uncertainty persists regarding the clinically significant EBV levels for these patients. Guidelines recommend initiating EBV monitoring no later than four weeks post-HCT and conducting it weekly. Pre-emptive therapies, such as the reduction of immunosuppressive therapy and the administration of rituximab to treat EBV viral loads are also suggested. In this study, we investigated the occurrence of EBV-PTLD in 546 HCT recipients, focusing on the clinical manifestations and risk factors associated with the disease. We managed to identify 67,150 viral genomic copies/mL as the cutoff point for predicting PTLD, with 80% sensitivity and specificity. Among our cohort, only 1% of the patients presented PTLD. Anti-thymocyte globulin (ATG) and GVHD were independently associated with lower survival rates and higher treatment-related mortality. According to our findings, prophylactic measures including regular monitoring, pre-emptive therapy, and supportive treatment against infections can be effective in preventing EBV-related complications. This study also recommends conducting EBV monitoring at regular intervals, initiating pre-emptive therapy when viral load increases, and identifying factors that increase the risk of PTLD. Our study stresses the importance of frequent and careful follow-ups of post-transplant complications and early intervention in order to improve survival rates and reduce mortality.

Salting-out homogeneous liquid-liquid microextraction for the determination of azole drugs in human urine: Validation using total error concept.

A salting-out homogeneous liquid-liquid microextraction was proposed for the quantification of four azole drugs in human urine prior to high-performance liquid chromatography analysis. The procedure involved the mixing of the sample with acetonitrile in appropriate volumes followed by the addition of sodium sulfate solution in order to facilitate phase separation. The parameters influencing the extraction performance were studied and optimized using a two-step experimental design. The analytical procedure was thoroughly validated using the accuracy profiles as a graphical decision-making tool. The ß-expectation tolerance intervals did not exceed the acceptance criteria of ±15% meaning that 95% of future results will be included in the defined bias limits. The limits of detection of the procedure were satisfactory, ranging between 0.01 and 0.03 µg/mL. The mean analytical bias in the spiking levels was satisfactory and ranged between -10.3 and 4.2% while the relative standard deviation was lower than 5.6%. Monte-Carlo simulations followed by capability analysis were employed to investigate the ruggedness of the sample preparation protocol. The developed method offers advantages compared to previously reported approaches for the same type of analysis including extraction efficiency and scaling down of the sample volume and extraction time.

Patient risk stratification and tailored clinical management of post-transplant CMV-, EBV-, and BKV-infections by monitoring virus-specific T-cell immunity.

Background: Despite routine post-transplant viral monitoring and pre-emptive therapy, viral infections remain a major cause of allogeneic hematopoietic cell transplantation-related morbidity and mortality. Objective: We here aimed to prospectively assess the kinetics and the magnitude of cytomegalovirus-(CMV), Epstein Barr virus-(EBV), and BK virus-(BKV)-specific T cell responses post-transplant and evaluate their role in guiding therapeutic decisions by patient risk-stratification. Study design: The tri-virus-specific immune recovery was assessed by Elispot, in 50 consecutively transplanted patients, on days +20, +30, +60, +100, +150, +200 post-transplant and in case of reactivation, weekly for 1 month. Results: The great majority of the patients experienced at least one reactivation, while over 40% of them developed multiple reactivations from more than one of the tested viruses, especially those transplanted from matched or mismatched unrelated donors. The early reconstitution of virus-specific immunity (day +20), favorably correlated with transplant outcomes. Εxpanding levels of CMV-, EBV-, and BKV-specific T cells (VSTs) post-reactivation coincided with decreasing viral load and control of infection. Certain cut-offs of absolute VST numbers or net VST cell expansion post-reactivation were determined, above which, patients with CMV or BKV reactivation had >90% probability of complete response (CR). Conclusion: Immune monitoring of virus-specific T-cell reconstitution post-transplant may allow risk-stratification of virus reactivating patients and enable patient-tailored treatment. The identification of individuals with high probability of CR will minimize unnecessary overtreatment and drug-associated toxicity while allowing candidates for pre-emptive intervention with adoptive transfer of VSTs to be appropriately selected.

Low pressure separations using automated flow and sequential injection analysis coupled to monolithic columns.

Automation is a key demand in modern analytical chemistry. Automated analytical schemes facilitate samples handling, and enable effective processes such as dilution, extraction, derivatization, and preconcentration to be carried out. Flow (FI) and sequential injection (SI) analysis are well-established and mature automated analytical techniques with more than 18,000 publications so far in all areas of analytical science. FI and SI offer significant advantages such as low instrumental and operational cost, widely available instrumentation, and effective automation of critical steps in the analytical process. Until recently, the main disadvantage of FI and SI was the inability of simultaneous determinations of more than two analytes in a single run. Due to the low pressure operation of these techniques, it was impossible for them to be coupled to conventional particulate-based separation columns that enable chromatographic separations. This drawback was overcome by the introduction of monolithic stationary phases. Monolithic columns are prepared from organic and silica monomers. Silica-based monoliths have small-sized skeletons and a bimodal pore size distribution with microm-sized throughpores and nm-sized mesopores. This gives silica-based monoliths favorable properties for high-efficiency fast separations, such as low-pressure drop across the column, fast mass transfer kinetics and a high binding capacity. They consist of a single rigid porous rod, enabling higher flow rates than particulate columns at reasonable back-pressures. These unique features of monolithic columns enabled their incorporation in low/moderate pressure setups, such as FI and SI, expanding dramatically their possibilities.

Flow and sequential injection methods for the spectrofluorimetric determination of aluminium in pharmaceutical products using chromotropic acid as chromogenic reagent.

This work reports rapid and sensitive FI and SI spectrofluorimetric methods for the determination of aluminium in pharmaceutical formulations. The methods are based on the reaction of aluminium with chromotropic acid (CA) in acidic medium to form a water-soluble complex (lambdaex.=360 nm, lambdaem.=385 nm). The proposed methods were validated in terms of linearity, repeatability, detection limit, accuracy and selectivity. The calibration curves were linear over the range of 0.03-2.0 and 0.1-4.0mg/l of aluminium using the FI and SI assays, respectively. The repeatabilities (sr=0.8% and 1.1% at 1mg/l aluminium using the FI and the SI assay, respectively, n=12) were satisfactory. The FI and SI methods proved to be adequately selective and sensitive with respective 3sigma limits of detection equal to cL=0.01 and 0.03 mg/l Al(III). The sampling rates were 120 and 72 h(-1) with the FI and SI assay. The methods were applied successfully to the analysis of pharmaceutical formulations (tablets and suspensions). The results were in good agreement with those by an official reference method and the nominal values of the pharmaceutical products.

Development and validation of a rapid ultra high pressure liquid chromatographic method for the determination of methylxanthines in herbal infusions.

An ultra high pressure liquid chromatographic method coupled with diode array detector (UHPLC-DAD) has been developed and validated for the fast separation and determination of three major methylxanthines, i.e., caffeine, theophylline and theobromine, in various herbal beverages. Isocratic elution using 0.1vol% formic acid/CH3OH (92.5:7.5, v/v) enabled the completion of the separation cycle in less than 3min using a flow rate of 0.7mL/min and a column temperature of 50°C. Validation of the method included linearity (0.5-50mg/L), limits of detection (12-35µg/L) and quantification (40-120µg/L), precision, matrix effect and accuracy. The percent recoveries ranged between 90 and 108%.

Development and validation of a rapid HPLC method for the determination of five banned fat-soluble colorants in spices using a narrow-bore monolithic column.

This work reports a fast and simple liquid chromatographic method for the simultaneous determination of five banned fat-soluble synthetic colorants, namely Sudan I-IV and Para-Red, in spice samples. The analytes were successfully separated isocratically in less than 5 min on the new narrow bore monolithic column, FastGradient(®) Chromolith (50mm × 2.0mm i.d.) using a mobile phase of 0.1% (v/v) HCOOH/acetonitrile (35/65%, v/v) at a flow rate of 1.5 mL min(-1). All colorants were detected at 506 nm. The main parameters (mobile phase composition, flow rate, injection volume) affecting the separation were studied. The proposed method was thoroughly validated in terms of linearity, LODs, precision and accuracy. The method was applied to the determination of the studied azo-dyes in various spices (paprika, chilli and mixed spice powders) after ultrasound-assisted extraction. Satisfactory recoveries, ranging from 92% to 109% were obtained.

Selective stopped-flow sequential injection method for the spectrophotometric determination of titanium in dental implant and natural Moroccan phosphate rock.

The present work reports the first sequential injection (SI) method for the spectrophotometric determination of Ti(IV). The method is based upon the reaction of Ti(IV) with chromotropic acid (CA) in acidic medium to form a water-soluble complex (lambda(max)=420nm). The chemical and instrumental variables of the system that affected the reaction were studied. Selectivity was greatly enhanced using ascorbic acid. A linear calibration graph was obtained in the range 0.2-10.0mgl(-1) Ti(IV) at a sampling frequency of 24h(-1). The precision was satisfactory (s(r)=1.5% at 5.0mgl(-1) Ti(IV), n=12) and the 3sigma limit of detection, c(L), was 0.7mgl(-1) (n=10). The developed method proved to be adequately selective and was applied successfully to the analysis of real samples (dental implant and natural Moroccan phosphate rock) giving accurate results based on recovery studies (98-105%).

Flow injection direct spectrophotometric assay for the speciation of trace chromium(III) and chromium(VI) using chromotropic acid as chromogenic reagent.

A new rapid and sensitive FI assay is reported for the simultaneous direct spectrophotometric determination of trace Cr(VI) and Cr(III) in real samples. The method is based upon the reaction of Cr(VI) with chromotropic acid (CA) in highly acidic medium to form a water-soluble complex (lambda(max)=370nm). Cr(III) reacts with CA only after its on-line oxidation to Cr(VI) by alkaline KIO(4). The determination of each chromium species in the sample was achieved by absorbance differences. The calibration curves were linear over the range 3-4000mugl(-1) and 30-1200mugl(-1) for Cr(VI) and Cr(III), respectively, while the precision close to the quantitation limit was satisfactory in both cases (s(r)=3.0% for Cr(VI) and 4.0% for Cr(III) (n=10) at 10 and 50mugl(-1) level, respectively). The method developed proved to be adequately selective and sensitive (c(L)=1 and 10mugl(-1) for Cr(VI) and Cr(III), respectively). The application of the method to the analysis of water samples (tap and mineral water) gave accurate results based on recovery studies (93-106%). Analytical results of real sample analysis were in good agreement with certified values.