Browsing by Author "Khan, Faisal Masood"

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    Anti-leukemic Activity of Anti-thymocyte Globulin
    (2018-09-17) Dabas, Rosy; Storek, Jan; Khan, Faisal Masood; Morris, Don G.; Mahoney, Douglas J.
    Allogeneic hematopoietic stem cell transplantation (HCT) is a potentially curative therapy for hematologic malignancies. The most frequent indication is acute myeloid leukemia (AML). Relapse and graft-versus-host disease (GVHD) are the major causes of HCT failure. Most immunosuppressive drugs used for GVHD prophylaxis increase relapse, presumably due to inhibiting not only GVHD but also graft-versus-leukemia effect (GVL). Polyclonal rabbit anti-thymocyte globulin (ATG), now widely used for GVHD prophylaxis, is the only immunosuppressive drug reducing GVHD without increasing relapse. The reason for ATG not increasing relapse is not known. We hypothesized that this could be due to an anti-leukemic activity of ATG. I investigated the anti-leukemic activity both in vitro and in vivo (in patients). I first evaluated whether ATG at clinical concentrations kills leukemic blasts in vitro. I showed that ATG does kill leukemic blasts, via complement-dependent cytotoxicity (CDC) and direct induction of apoptosis. Next, I investigated whether ATG kills in vitro not only leukemic blasts but also leukemic stem cells (LSCs). I showed that ATG does kill LSCs, primarily via CDC, however, only at a higher concentration than needed for killing leukemic blasts. In spite of the anti-leukemic activity of ATG in vitro, in vivo ATG has so far been considered not to have an anti-leukemic activity as in 3/3 randomized studies ATG did not reduce relapse. We hypothesized that this could be due to differential effects of ATG pre- versus post-HCT. Specifically, we hypothesized that the direct anti-leukemic effect of ATG is countered by the anti-GVL effect of ATG post- but not pre-HCT. I evaluated associations between pre- versus post-HCT ATG area-under-the-curve (AUC) and relapse. I found that high pre-HCT AUC was associated with a low incidence of relapse. Conversely, there was a trend toward an association between high post-HCT AUC and a high incidence of relapse. The association between pre-HCT AUC and relapse is an indirect evidence for anti-leukemic activity of ATG in vivo. These findings are expected to lead to clinical studies harnessing the anti-leukemic effect of ATG, e.g., by dosing ATG so as to achieve a higher than conventional pre-HCT AUC and a conventional post-HCT AUC. This could lead to decreasing relapse without increasing GVHD which may lead to improved survival.
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    Biological and Advanced Oxidation Processes for the Treatment of Sulfolane Contaminated Waters
    (2020-01-07) Khan, Muhammad Faizan; Achari, Gopal; Black, Kerry E.; Kimura, Susana Y.; Gieg, Lisa Marie; Khan, Faisal Masood
    Sulfolane contamination has increasingly become a major environmental concern around the world. This research builds on past research on sulfolane degradation using a variety of different advanced treatment technologies. Initially, the performance of an integrated technology combining biological activated sludge with advanced oxidation process (AOP) (UVC/H2O2) in sequence was evaluated in a batch reactor resulting in >81% sulfolane degradation in less than 24 h. Evaluation of the impact of biological process on AOP showed sulfolane concentration beyond 30 mg/L and presence of TSS >44 mg/L can negatively impact the UVC/H2O2 efficiency for sulfolane degradation. The application of UVC/H2O2 after biological treatment was an advantage as UVC/H2O2 could perform dual roles of oxidation and disinfection. As aerobic granulation is perceived to be more advanced than activated sludge process, two approaches of forming sulfolane degrading aerobic granules (SDAG) were investigated. The adaptation of pre-grown granules to sulfolane environment required a longer period to form SDAG compared to coaggregation of pre-grown granules with bacterial culture native to sulfolane contaminated site. Scanning electron microscopic images revealed dominant filamentous bacteria on the surface of granules. The stability and settleability of SDAG were also investigated under different environmental conditions. Subsequently, a novel integration of aerobic granulation with UV/H2O2 process in a continuous flow-through operation sequence showed elimination of more than 99.99% of sulfolane in less than 6.3 h of combined retention time. The degradation kinetics of sulfolane were also evaluated and the flow-through system showed generation and maintenance of a healthy aerobic granular system. Additionally, various key factors were also identified that govern residual H2O2 concentration in UV/H2O2 effluents. Finally, a pilot-scale field investigation was conducted using a pressurized ozone treatment system to degrade sulfolane in contaminated groundwaters. A series of batch and continuous flow systems were studied to determine the degradation kinetics and evaluate augmentation of oxidation process with the addition of secondary chemicals with ozone. Groundwater matrix played a crucial role in the efficacy of ozone treatment and intermittently sparged ozone injection was evaluated as a viable option for ozone field applications. Nevertheless, bromate concentrations higher than drinking water guidelines were detected in treated groundwater after ozone treatment and this will need further research.
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    Measuring steroids from dried blood spots using tandem mass spectrometry to diagnose congenital adrenal hyperplasia
    (2018-09-10) Qasrawi, Deema Omar; Sadrzadeh, S. M. Hossein; Khan, Faisal Masood; Naugler, Christopher T.; Lewis, Ian A.
    Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders that occur due to defects in the steroidogenesis pathway within the adrenal glands. CAH is characterized by numerous clinical manifestations resulting from dysregulation of various enzymes in the steroidogenesis pathway. Approximately 90% of CAH cases can be diagnosed by the measurement of serum 17-hydroxyprogesterone alone. However, the quantification of six additional steroids, cortisol, 21-deoxycortisol, 11-deoxycortisol, androstenedione, pregnenolone and dehydroepiandrosterone could significantly improve CAH laboratory diagnosis. Although clinical laboratories predominantly use immunoassays to measure some of the above steroids, these assays are hampered by low specificity due to cross reactivity of antibodies to molecules with similar structures and high cost of antibodies used in the system. As CAH is diagnosed in neonates, using dried blood spot (DBS) as specimen of choice can further improve patient care due to the very small sample volume. This study aimed to develop a more specific and rapid assay to measure seven steroids using liquid chromatography mass spectrometry (LC-MS/MS) in DBS. An optimized DBS sample preparation method was employed without the need of derivatization. A LC-MS/MS assay was developed and optimized using reverse phase-ultra performance liquid chromatography (RP-UPLC) system combined with a triple quadrupole mass spectrometry using positive electrospray ionization (+ESI) mode. Each steroid was quantified using its deuterated or isotopically labelled internal standard. Calibration curve and quality control specimens were prepared in saline-washed erythrocytes mixed with steroid free serum to achieve a 55±1% hematocrit level. Prepared specimens were enriched with predetermined concentrations of the seven steroids and spotted onto Whatman 903® filter papers. The assay was validated according to CLSI analytical guidelines, including limit of detection (LOD) and lower limit of quantification (LLOQ), linearity, precision, and method comparison. The analytical measuring range of the method for all steroids was 2.5 were 0.11-1.8 ng/ml, 0.001-6.4 ng/ml, 1.8–11.5%, and 5.3-13.8%, respectively. This robust and inexpensive assay can be readily implemented in clinical laboratories equipped with LC-MS/MS and can provides superior analytical performance over traditional immunoassays for the diagnosis of CAH.