Relative Fluorescence Intensity Ratios Research Articles

Excellent Color Purity and Luminescence Thermometry Performance in Germanate Tellurite Glass Doped with Eu3+ and Tb3+

Germanate tellurite glasses doped with Eu3+ and Tb3+ were synthesized by the conventional melt-quenching method. There is no indication of the energy transfer between dopant ions in this host, but the co-dopants exhibit excellent color purity of 100% for Eu3+ and 80% for Tb3+. The co-doped glass exhibits yellow luminescence. The quantum yield of the Eu3+ emission is equal to 23% under 395 nm excitation. The thermal quenching of Eu3+ and Tb3+ luminescence occurs at different temperature ranges, which enables the thermal sensing properties of the material. The relative fluorescence intensity ratio (FIR) sensitivity of 0.16% K−1 was recorded in the wide range of temperatures spanning from −193 °C up to 0 °C. The temperature dependence of the decay times was also studied. The lifetime-based temperature sensitivity was determined to be 0.95% K−1 at 250 °C for Tb3+5D3 level emission and 0.3% K−1 at 225 °C for Eu3+5D1 level emission.

In Vitro Efficacy of Anti-HER2 CAR T-Cells in HER2 + BCP-ALL

Introduction: Around 30% of adults and 15% of children with B cell precursor acute lymphoblastic leukemia (BCP-ALL) relapse after a first line of treatment. The prognosis of these patients remains poor. Recent advances have involved targeted therapies with monoclonal antibodies and chimeric antigen receptor (CAR) T-lymphocytes (anti-CD19 CAR T-cells), which have produced very encouraging results in the high risk BCP-ALL setting(Maude et al. 2018). Nevertheless, half of these patients relapse after such therapies. In a third of cases, the disease no longer expresses the antigen previously targeted. New targets are therefore needed. HER2 is expressed in above one third of adult BCP-ALL (Chevallier et al. 2004) and 10% of childhood BCP-ALL (Camuset et al. 2021). HER2 expression is associated with chemoresistance and poor prognosis (Chevallier et al. 2004) (Camuset et al. 2021). The anti-HER2 antibody trastuzumab was prospectively tested in adult patients with HER2+ BCP-ALL, but yielded disappointing results (Chevallier et al. 2012). Anti-HER2 CAR T-cells could be an interesting alternative. Indeed, they have shown encouraging preclinical efficacy in solid tumors expressing HER2/neu (Budi et al. 2022). The present work was designed to evaluate, in vitro, the sensitivity of HER2+ BCP-ALL to anti-HER2 CAR engineered Epstein Barr virus (EBV) specific T-cells. Methods: DMSO-frozen cell-samples from 6 HER2+ BCP-ALL patients were available for this study. Patient characteristics are shown in Table 1. Blast cells from patient samples were preferred to cell lines in order to be more representative of BCP-ALL biology. level of HER2 expression on BCP-ALL samples was determined by flow cytometry and compared to the HER2 expressing breast-cancer cell line BT474. Anti-EBV cytotoxic T lymphocytes (CTLs), armed with a trastuzumab-based scFv-CH2-CH3-IgG2A-FcεRIγ chimeric receptor as previously described (Clémenceau et al. 2015) were used for long-term cytoxicity assays. For 4 samples, non-transduced anti-EBV CTLs were used as controls. Cytotoxic activity was assessed at a 3-to-1 effector-to-target ratio, in a flow cytometry assay. Cells were harvested at H0, H4 and H24 and stained with a viability stain (VS780). Further staining with anti-CD22 or anti-CD24 (depending on the BCP-ALL immunophenotype) and anti-CD3 antibodies allowed to characterize blast cells and CAR T-cells respectively. The study was approved by the local review board and two alive patients provided informed consent. Results: The level of HER2 expression by the 6 HER2+ BCP-ALL samples was variable with a median relative fluorescence intensity ratio (RFI) of 9 (range 1.8 to 16). These levels of expression were lower than those of the BT474 cell line (RFI= 79). No BCP-ALL lysis was observed when cells were incubated with trastuzumab alone (not shown). When co-cultured with non-transduced anti-EBV CTLs (CAR negative) (n=4), a decrease of residual viable BCP-ALL cells was observed at variable levels (Figure 1A). The lysis observed at 24h was possibly due to allogeneic recognition since anti-EBV CTLs were not autologous to the leukemias tested. Conclusion: This study first reveals that, although CTLs with TCRs restricted to EBV antigens and therefore intrinsically low allo-specificity were used, CAR-independent lysis was observed in 24 hours co-culture with BCP-ALL cells. These results underline the need for cautious interpretation of cytotoxicity test results in an allogeneic setting. Secondly, these preliminary data suggest that an anti-HER2 CAR T-cell approach could be promising for BCP-ALL even with weak antigen expression. Anti-EBV CTLs have already been used as a platform for CAR-engineered T-cells (Rossig et al. 2017). Should the cytotoxic activity of allogeneic EBV-CTL be proven to be specifically directed against BCP-ALL, the synergy between TCR and anti-HER2-CAR might be beneficial, and adoptive transfer of anti-HER2 CAR EBV CTLs could be a promising therapeutic option for patients with HER2+ BCP-ALL. * This research is funded by the non-profit organization Etoile de Martin/SFCE.

A novel dual emission ratiometric fluorescence sensor Eu3+/CDs@UiO-66 to achieve Cu2+ detection in water environment

A novel dual-emission ratiometric fluorescent sensor Eu3+/CDs@UiO-66 was synthesized by post-synthesis modifying of UiO-66, a zirconium-based MOF formed by 1,4-phthalic acid (PTA) and Zr4+ , with europium ion (Eu3+) and carbon dots (CDs) and utilized for the determination of Cu2+ ions. The prepared composites not only maintain the excellent optical properties of CDs and Eu3+ but also have good stability in an aqueous solution. At the excitation wavelength of 299 nm, Eu3+/CDs@UiO-66 has two distinct emission peaks at 394 nm and 615 nm, respectively. More interestingly, when the material was dispersed in an aqueous solution containing Cu2+ ions, the characteristic peak of Eu3+ at 615 nm decreased significantly, while the characteristic peak of CDs at 394 nm remained unchanged. In the range of 0–500 μM, the relative fluorescence intensity ratio (F394/F615) linearly increased with increasing Cu2+ ion concentration, and the detection limit was calculated to be 51 nM (3Sb/Ksv). At the same time, the material can also be effectively applied to the detection of Cu2+ in environmental water samples. So Eu3+/CDs@UiO-66 can be developed as a potential ratiometric fluorescent sensor to detect Cu2+ ions.

Laparoscopic duodenum–preserving pancreatic head resection with real-time indocyanine green guidance of different dosage and timing: enhanced safety with visualized biliary duct and its long-term metabolic morbidity

PurposeLaparoscopic duodenum–preserving pancreatic head resection (L-DPPHR) is technically demanding with extreme difficulty in biliary preservation. Only a few reports of L-DPPHR are available with alarming bile leakage, and none of them revealed the long-term metabolic outcomes. For the first time, our study explored the different dosage and timing of indocyanine green (ICG) for guiding L-DPPHR and described the long-term metabolic results.MethodsBetween October 2015 and January 2021, different dosage and timing of ICG were administrated preoperatively and evaluated intra-operatively using Image J software to calculate the relative fluorescence intensity ratio of signal-to-noise contrast between bile duct and pancreas. Short-term complications and long-term metabolic disorder were collected in a prospectively maintained database and analyzed retrospectively.ResultsTwenty-five patients were enrolled without conversion to laparotomy or pancreaticoduodenectomy. Administrating a dosage of 0.5 mg/kg 24 h before the operation had the highest relative fluorescence intensity ratio of 19.3, and it proved to guide the biliary tract the best. Fifty-six percent of patients suffered from postoperative complications with 48% experiencing pancreatic fistula and 4% having bile leakage. No one suffered from the duodenal necrosis, and there was no mortality. When compared with the non-ICG group, the ICG group had a comparable diameter of tumor and similar safety distance from lesions to common bile duct; however, it decreased the incidence of bile leakage from 10% to none. The median length of hospital stay was 16 days. After a median follow-up of 26.6 months, no one had tumor recurrence or refractory cholangitis. No postoperative new onset of diabetes mellitus (pNODM) was observed, while pancreatic exocrine insufficiency (pPEI) and non-alcoholic fatty liver disease (NAFLD) were seen in 4% of patients 12 months after the L-DPPHR.ConclusionL-DPPHR is feasible and safe in selected patients, and real-time ICG imaging with proper dosage and timing may greatly facilitate the identification and the prevention of biliary injury. And it seemed to be oncological equivalent to PD with preservation of metabolic function without refractory cholangitis.

A “bottle-around-ship” method to encapsulated carbon nitride and CdTe quantum dots in ZIF-8 as the dual emission fluorescent probe for detection of mercury (II) ion

A facile and efficient "bottle-around-ship" approach for preparing the ratiometric fluorescent probe has been developed by encapsulating the red-colored fluorescence CdTe quantum dots (QDs) and blue-colored fluorescence graphitic carbon nitride quantum dots (g-CNQDs) into the zeolitic imidazolate metal-organic frameworks (ZIF-8) in one step. At a single excitation of 360nm, the obtained probe ZIF-8@g-CNQD/CdTe shows the dual-emission peaked at 450 and 633nm, respectively. The red emission of CdTe QDs is selectively quenched by the Hg2+, whereas the blue fluorescence of g-CNQDs as an internal reference is insensitive, resulting in an apparent color transformation from pink to blue for special recognition of Hg2+. By this approach, the relative fluorescence intensity ratio (F633/F450) decreased linearly with increasing Hg2+ concentration in the 0.2-3.5μM range with a low limit of detection (LOD) of ~ 46nM. Therefore, we demonstrate that this "bottle-around-ship" process provides a new strategy for the construction of ratiometric fluorescent Hg2+ probes with good simplicity, high efficiency, and excellent stabilities. Moreover, the obtained Hg2+ fluorescent probe shows good results in the detection of actual samples.

White pepper-derived ratiometric carbon dots for highly selective detection and imaging of coenzyme A

A new-style white pepper derived dual-emission carbon dots (CDs) with a quantum yield of 10.4% was designed and facile constructed with one-pot solvothermal method. The green emission (520 nm) had an efficient and special “turn-on” fluorescence sensing of coenzyme A (CoA) with the aid of Cu2+, while red emission (668 nm) barely changed and worked as reference. In the concentration range (0–150 µM), relative fluorescence intensity ratios (F520/F668) showed excellent linear correlation with concentrations of CoA, and detection limit was as low as 8.75 nm. Moreover, the strategy has been successfully applied for label-free detection of CoA in real pig liver samples with good recoveries (93.3–108.0%). Notably, the synthesized CDs had durable fluorescence, low cytotoxicity, and good biocompatibility for cellular imaging, which demonstrated wide and promising applicability for biosensing and bioimaging in the future.

A label-free luminescent light switching system for miRNA detection based on two color quantum dots

In this study, we report a novel switchable fluorescent nanobiosensor for detection of miRNA. The sensor consists of green-emitting and orange-emitting CdTe QDs exhibiting emission spectra at 525 and 599 nm respectively, under excitation wavelength of 360 nm. Following the addition of miRNA targets to the DNA probes and heteroduplex formation of the hybrid, Green fluorescence CdTe QDs were aggregated and quenched by the DNA/miRNA hybrid via strong interactions at their metal centers. Then, with the addition of orange emitting QDs causes the fluorescence energy transfer to occur and was introduced as a ratiometric approach for miR-155 detection. The relative fluorescence intensity ratio was directly proportional to the concentration of miR-155 from 20 to 100 pM and the detection limit was determined at 14.0 pM. The novel nanobiosensor is “light-on”, rapid, and convenient while it does not require modification or separation procedures and can be applied for the detection of miRNAs in cell lysis with satisfactory results.

A novel optical fiber glucose biosensor based on carbon quantum dots-glucose oxidase/cellulose acetate complex sensitive film

A novel optical fiber glucose biosensor based on fluorescent carbon quantum dots (CQDs)-glucose oxidase (GOD)/cellulose acetate (CA) complex sensitive film was fabricated, in which the dip-coating method was adopted to immobilize the CQDs-GOD/CA complex sensitive film onto the end face of the optical fiber. The surface morphology, microstructure and optical performances of the sensitive film were characterized by field emission scanning electron microscope (FESEM), atomic force microscope (AFM), Zeiss Axiovert 25 inverted microscope, Fourier transform infrared spectroscopy (FTIR), Ultraviolet–visible spectrophotometer and fluorescence spectrophotometer, respectively. The developed fiber-optic biosensor exhibits high sensitivity and repeatability for continuous online detection of low concentration glucose, allowing visualization of real-time glucose fluctuations over a period of time. The change ratios in fluorescence intensity of the biosensor are linear with glucose concentration in various ranges including micromole and nanomole levels, and the relationship between relative fluorescence intensity ratio and glucose concentration complies well with the modified Stern-Volmer equation in the range of 10–200 μmol/L with the detection limit of 6.43 μM, and in the range of 10–100 nmol/L with the detection limit of 25.79 nM, respectively.

A ratiometric fluorometric epinephrine and norepinephrine assay based on carbon dot and CdTe quantum dots nanocomposites

A ratiometric fluorescence nanoprobe, consisted of water-soluble fluorescent carbon dots (CDs) and 3‑mercapropionic acid-coated cadmium telluride quantum dots (CdTe QDs), was constructed for the detection of epinephrine (EP) and norepinephrine (NE). Under single-wavelength excitation (370 nm), the hybrid nanoprobe possessed dual emission peaks at 460 and 610 nm belongs to CDs and CdTe QDs, respectively. CdTe QDs fluorescence was quenched by EP or NE via electron transfer from QDs to the oxidation products of catecholamines, while the fluorescence intensity of CDs remained almost constant, which provided a ratiometric fluorescence assay for the catecholamines detection. The relative fluorescence intensity ratios were directly proportional to the concentration of catecholamines. Meanwhile, some structural analogues of the target molecules, including dopamine hydrochloride and isoprenaline hydrochloride, had no significant interference for the detection mode. The novel fluorescence detection platform was rapid and convenient, and applied to the detection of EP and NE in human serum samples with satisfactory results.

In Vitro Comparison of ADCC and CAR Sensitivity of Adult HER-2+ B-ALL Using the NK-92 Human Cell Line Transduced with a Human CD16 (ADCC) or an Anti-HER2 Chimeric Antigen Receptor (CAR)

Introduction: Prognosis of acute lymphoblastic leukemia (ALL) in adults remains dismal. Recent advances have consisted of targeted therapies with monoclonal antibodies and chimeric antigen receptor (CAR) T lymphocytes (anti-CD19 CAR T cells), showing very encouraging results. However, relapse still occur after this new therapeutics and increasing the armamentarium for ALL is still required. Her2 is expressed in above one third of adult B-ALL (Chevallier,Haematologica 2009). The anti-HER2 antibodytrastuzumab has been tested prospectively in such patients, showing a low efficacy (Chevallier, Blood 2012).The present work was designed to compare, in vitro, thelysis sensibility of B-ALL HER2+ mediated by two mechanisms of HER2 recognition based on antibody (Ab) specificity: firstly, when the anti-HER2 monoclonalAbtrastuzumab bridges target cells and cytotoxic lymphocytes armed with a Fc receptor (antibodydependant cellular cytotoxicity, ADCC) andsecondly, when HER2-positive target cells are directly recognized by cytotoxic lymphocytes armed with a chimeric antigen receptor (anti-HER2 CAR).Methods: Frozen samples from 7 HER2+ B-ALL adults were available, including onesample expressing also CD20. Characteristics of Patients and controls are presented in Table 1.Three human breast-cancer cell lines (BCCL) expressing different validated (HercepTest, Dako) levels of HER2 (BT474 (HER2 3+), MCF-7 (HER2 0-/1+) and MDA-MB-231 (HER2 0-/1+) were used as positive control. Leukemic HER2-negative B-ALL cells from two patients were used as negative control, including one patient with CD20+ expression. The level of HER2 expression by HER2+ B-ALL was determined by fluorescence-activated cell sorter (FACS) and compared to the HER2 expressing BCCL.Cytotoxic activity was assessed at a 30-to-1 effector-to-target ratio in a 4 hours 51Cr-release assay.We used the same cytotoxic effector lymphocytes (the human NK cell line NK-92), armed with eitheraFcγRIIIa/FcεRIγ receptor (referred to as NK-92CD16) or with an anti-HER2/FcεRIγ CAR receptor (referred to as NK-92CAR) as previously described (Clémenceau, JImmunol Research 2015). For ADCC/CAR assays, target cells were pre-incubated withtrastuzumab and /or rituximab at 10µg/ml each.The study was approved by our local review board and twoalivepatients gave informed consent.Results:The level of HER2 expression by HER2+ B-ALL (n=7) was highly variable with a mean relative fluorescence intensity ratio (RFI) of 13 (range 5 to 30). According to the HercepTestranking used for BCCL lines (see above) all B-ALL would be classified as HER2 0-/1+. In vitro HER2+ BCCL were efficiently lysed by anti-HER2 NK-92CAR in this 4 hours 51Cr-release assay and this direct pathway of killing by CAR was always more efficient than the indirect pathway mediated by ADCC. In addition, thelysis level was correlated to HER2 level expression.Trastuzumabalone has no effect on the spontaneous 51Cr-release of B-ALL cells (not shown). Anti-HER2 CAR mediatedlysis was observed for 5 out of 6 HER2+ B-ALL cells (83%, 1 case (#5) non interpretable). Although lysis levels were low, they werespecificsince the CAR mediatedlysis was inhibited when the B-ALL were pre-incubated with 10 µg/mltrastuzumab (not shown). In contrast, for these 5 HER2+ B-ALL, no anti-HER2 ADCClysis was observed. These results confirmed that in these experimental conditions, HER2 targeting by CAR is more efficient than by ADCC. For the two HER2- B-ALL, no ADCC or CARlysis were observed.Finally, for the two B-ALL expressing CD20, anti-CD20 ADCClysiscan be observed demonstrating that B-ALL cells are not intrinsically resistant to ADCCcytoxicity. Regarding the unique case of B-ALL expressing both CD20/HER2 antigens, only anti-CD20 ADCClysiswas observed. Results are presented in Table 2.Conclusion:Together, these preliminary results suggest that for the CD20-negative and HER2-positive B-ALLs, one cannot rely on ADCC as a mechanism of target celllysis, while the interest of an anti-HER2-CAR approach deserve further studies to better correlate the level of HER2 expression and the sensitivity tolysisby HER2-specific CAR. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Determination of metolcarb in food by capillary electrophoresis immunoassay with a laser‐induced fluorescence detector

A capillary electrophoresis immunoassay (CEIA) was developed for the determination of trace metolcarb (MTMC) in food. The method was based on the competitive reactions between fluorescently labeled MTMC tracer and free MTMC with a limited amount of anti-MTMC antibody and the separation and determination by CE with LIF detector. A fluorescent reagent, FITC was labeled on MTMC to construct an immunofluorescent probe. CEIA experimental parameters such as the pH value and concentration of the running buffer and separation voltage as well as incubation time were systematically investigated. Under the optimized conditions, fluorescently labeled antigen and antibody bound could be well separated within 3 min using Na₂B₄O₇/NaH₂PO₄ buffer (20:10 mmol/L, pH 9.0) for background electrolyte, 20 kV for the separation voltage, and 20°C for the column temperature. The linear range of the method was 0.25-50.0 μg/L with LOD 0.07 μg/L. The RSD for relative migration time and relative fluorescence intensity ratio were 2.90% (intraday) and 4.73% (intraday), respectively. The proposed method has been applied to determine the residue of MTMC in food samples with the satisfactory recovery.

Determination of Nerve Growth Factor in Rat Spinal Cord by Capillary Electrophoresis-Based Immunoassay with a Laser Induced Fluorescence Detector

In order to study the relationship between spinal cord injury and the change of nerve growth factor (NGF), an analytical method for NGF by capillary electrophoresis-based immunoassay (CEIA) with laser-induced fluorescence (LIF) was developed. Having been dissolved in phosphate buffer solution and concentrated with vacuum freeze-drying, NGF in spinal cord of rat was allowed to react with NGF monoclonal antibody labeled with fluorescence isothiocyanate (FITC). Then the immuno-complex, FITC-labeled anti-NGF and FITC were separated and determined by LIF-CEIA using Kiton red as the internal standard. The linear range of the method was 2–30 ng mL−1 and the limit of detection was 0.35 ng mL−1. The relative standard derivations for relative migration time and relative fluorescence intensity ratio were 7.98% and 6.52%, respectively. The contents of NGF from spinal cord of rat were determined by both the proposed method and Western blotting. The results with the two methods agreed well. The spiked recoveries of the samples were 88.5–116.3%. The proposed method was rapid, precise and inexpensive.

Ratiometric Fluorescent Mercuric Sensor Based on Thiourea−Thiadiazole−Pyridine Linked Organic Nanoparticles

A novel “naked-eye” and ratiometric fluorescent Hg2+ probe based on thiourea−thiadiazole−pyridine linked (TTP) fluorescent organic nanoparticles (FONs) was designed and synthesized. TTP FONs show good water solubility; a 46-fold increase in fluorescence quantum yield, high selectivity for sensing, and a 98 nm red shift of the fluorescence emission upon binding Hg2+ in aqueous media are observed. Under the optimum conditions, the relative fluorescence intensity ratio, I501/I403, is increased linearly with the increasing logarithmic concentration of Hg2+ in the range of 2.5−40 μM with a detection limit of 1.13 × 10−7 M (22.6 ppb), whereas the fluorescence intensity of TTP FONs to other metal ions, including Na+, Ca2+, Ni2+, Cd2+, Cu2+, Ag+, Pb2+, Mn2+, and Mg2+, is negligible. The possible mechanism is discussed.

Ratiometric fluorescent determination of cysteine based on organic nanoparticles of naphthalene–thiourea–thiadiazole-linked molecule

Novel ratiometric fluorescent cysteine probes based on naphthalene–thiourea–thiadiazole (NTTA) fluorescent organic nanoparticles (FONs) were designed and synthesized. NTTA FONs show good water solubility, high selectivity for sensing and a 74 nm red-shift of fluorescence emission upon binding cysteine in aqueous media are observed. Under optimum condition, linear relationships are found between the relative fluorescence intensity ratio I 430/ I 356 and the logarithmic concentration of cysteine in the range of 0–100 μM with the detection limit was found to be 1.5 × 10 −9 M, while the FL intensity of NTTA FONs to other amino acids is negligible. The possible mechanism is discussed.

Modeling the Relative Fluorescence Intensity Ratio of Eu(III) Complex in Different Solvents Based on QSPR Method

The quantitative structure-property relationship approach was performed to study the relative fluorescence intensity ratio (R) of Eu(DBM)(3)Phen (DBM-dibenzoylmethane, Phen-1,10-phenanthroline) in 34 different solvents. The multilinear regression analysis and artificial neural networks were employed to develop linear and nonlinear models, respectively. The proposed linear model contains six descriptors, with the squared correlation coefficient r(2) = 0.955 and the standard error of estimation s = 1.02. Better predictive results were obtained from the nonlinear model, with r(2) = 0.987 and s = 0.51. The descriptors involved in the models were discussed in detail too.

Study of 660 nm laser-induced photoluminescence of chlorophyll-a and its applications

Based on the phenomenon of chlorophyll a photoluminescence, this paper introduces a new method to measure the chlorophyll a content, using 660nm laser diode as a new kind of light source to stimulate fluorescence as well as combining a fiber and spectrum technique. We analyze the characteristics of laser-induced fluorescence spectrum of chlorophyll a and then put forward the new method using two parameters, the relative fluorescence intensity and fluorescence intensity ratio F685/F735, to measure the chlorophyll a content in the water and green leaves respectively. The experimental results indicate that it is completely feasible to give a visual judgment for chlorophyll a content, according to the fluorescence emission spectrum of chlorophyll a. Subsequently, it is verified by three kinds of typical applications. All of these provide a new kind of light source to develop the chlorophyll a fluorometry and further give a technical foundation of on-spot monitoring the chlorophyll a content in the ocean or in green leaves.

Apoptotic and Multi-Drug Resistance Profile in Elderly AML Patients.

Elderly AML patients have an unfavorable prognosis with frequent resistance of leukemic cells to chemotherapy. The expression of proteins related with apoptosis and multi-drug resistance have been involved in chemotherapeutic resistance in AML; however, these proteins are not only expressed on leukemic but also on normal cells. Moreover, within leukemic cells, different stages of maturation may occur. The aim of the present study was to evaluate the expression of proteins related to apoptosis (APO 2.7, bax, and bcl-2), and drug resistance (P-gp, MRP, LRP) in a series of 117 elderly AML patients (median age of 70) uniformly treated according with the Spanish Pethema cooperative group protocol (LMA >65). 63 patients (54%) achieved complete remission (CR), with a median relapse free survival (RFS) of 9.2 months. In the bone marrow (BM) pre-treatment, we performed a four-color staining technique (APO2.7, bax or bcl-2 with CD32/CD34/CD45; and P-gp, MRP, or LRP with CD34/CD19/CD33), allowing the identification of myeloid blast cells, and the discrimination between stages of maturation of blast cell subsets. Samples were acquired on a FACSCalibur flow cytometer (Becton/Dickinson), and appropriate controls were used in each individual sample and, accordingly, antigen expression in individual cell samples was quantified as relative fluorescence intensity (RFI) (ratio blast cell/control mean channel fluorescence value). Our results showed that the level of expression of MRP and LRP was significantly higher (mean±SD of MFI 2.0±0.75 vs 2.7±1.87 and 4.5±2.2 vs 7.0±6.2, respectively -p <0.03-) in cases that did not achieved CR with one or two cycles of chemotherapy. Although different patterns of expression of apoptosis or drug resistance-associated proteins were detected according with the stage of maturation on myeloid blast cells, we did't found any other correlation between levels of bcl-2, bax, APO 2.7, bcl-2/bax ratio or MDR and probability of achieving morphological CR. In addition, CD34 expression on blast cells had also significant influence on response (CR was achieved in 81% of CD34 negative cases vs only 46% of CD34 positive cases; p= 0.005). We didn't found any influence of apoptosis and/or drug-resistance proteins expression in relapse rate nor RFS. Variables influencing RFS were age (p=0.04), and number of cycles to achieve CR (p=0.01); while only WBC count (p=0.05) influenced overall survival (OS). We conclude that MRP and LRP could have a role in the resistance to induction treatment in elderly AML patients but not in RFS or OS.

The Effect of Zinc Ions on the Fluorescence Spectra of (Ln, Zn)of:Eu3+(Ln=Y, La and Gd) Powder Phosphors

This research note reports the fluorescence properties of Eu3+-doped in three sets of (Y-Zn, La-Zn and Gd-Zn) oxy fluoride powder phosphors. on excitation with a UV-source, these phosphors have displayed orangish-red color and for which the chromaticity coordinates ([Xbar], [Ybar] have been computed. the relative fluorescence intensity ratios (R) for the different measured emission transitions have been evaluated in order to examine the effect of substitution of zinc ions in the host matrix on the fluorescence behavior. Scanning electron microscopy studies have also been performed to investigate the average grain size of the synthesized phosphor material.

Fluorescence spectra of Eu 3+-doped LnVO 4 (Ln = La and Y) powder phosphors

The fluorescence properties of Eu 3+-doped LaVO 4, (La 0.75,Y 0.25)VO 4, (La 0.5,Y 0.5)VO 4, (La 0.25,Y 0.75)VO 4, and YVO 4 powder phosphors are reported. The phase purity was checked by XRD and FT-IR spectra. The values of relative fluorescence intensity ratios (R) and color coordinates (X̄,Ȳ) were found to increase significantly with an increase in the yttrium concentration. Both thermal analysis and scanning electron microscopy (SEM) studies were carried out to characterize the samples.

Fluorescence spectra of Eu 3+ and Tb 3+-doped lanthanide oxychloride powder phosphors

The fluorescence spectra of Eu 3+ and Tb 3+-doped YOCl, LaOCl, GdOCl, (La,Gd)OCl, (La,Y)OCl and (Gd,Y)OCl powder phosphors are reported and they are analysed by evaluating the colour coordinates ( X ̄ , Y ̄ ) and also the relative fluorescence intensity ratios ( R). The Eu 3+ : phosphors have displayed bright red emission ( 5D 0 → 7F 2) and Tb 3+ : phosphors green emission ( 5D 4 → 7F 5) under an UV source.