Removal of Brilliant Blue R from Aqueous Solutions on Activated Carbon Produced from Carbonaceous Substrate

Adsorption of brilliant blue R on activated carbon produced from the wood of Paulownia Tomentosa was investigated. Samples characterization by XRD, SEM, EDS and FTIR showed that the oxygen containing surface functional groups (carboxyls, lactones or phenols and ethers) were present on the surface which were eliminated at 800°C. Activation at 800°C, resulted in the opening of porous structure thereby increasing the adsorption capacity. Relatively high amounts of carbon with respect to oxygen were found in the samples with the rise in activation temperature. The adsorption kinetic at 10 and 45°C showed that the first order, Bangham and parabolic diffusion models are applied to the data. The rate constant increased with the rise in temperature of adsorption/activation. Thermodynamic properties (ΔE≠, ΔH≠, ΔS≠ and ΔGo) for the adsorption process were calculated. Positive values of ΔH≠ showed that the adsorption of brilliant blue R is endothermic. Negative values of ΔS≠ reflected the decrease in the disorder of the system at the solid-solution interface during adsorption. The Gibbs free energy, which is the driving force for adsorption is negative indicating spontaneous adsorption. Freundlich and Langmuir models described the equilibrium adsorption data and Thomas model was used for the column study.

Removal of Acid Yellow 34 from Aqueous Solution by Activated Charcoal of Animal Bones

Activated charcoal prepared from the animal bones at different temperatures (600–1000°C) was characterized for surface area, pore volume and by FTIR, EDS, SEM and XRD techniques. The surfaces contained functional groups like carboxyl's and ketones which disappeared at above 800°C, favoring exposure of porous structural surfaces; resulting in enhancement of the adsorption capacity. At the high temperatures the carbon content in the charcoal increased while oxygen got decreased. Adsorption kinetics of acid yellow 34 on the prepared activated charcoal was studied at 10°C and 45°C. Bangham and Parabolic diffusion kinetic models fitted the adsorption data. The two components of the intraparticle diffusion plots suggested that the adsorption process proceeded by surface adsorption and intraparticle diffusion. The thermodynamic parameters of adsorption, such as rate constant (kad), activation energy (DE¿), enthalpy (DH¿) and entropy (DS¿) were evaluated from the first order rate kinetics. The enthalpy of activation (DH¿) indicated that the process was endothermic in nature and its values decreased with the increase in activation temperature. The negative entropy of activation DS¿ reflect the affinity of charcoal toward dye and it decreased with the increase in activation temperature indicating that the dye molecules take more oriented position on the surface of charcoal.

[Preliminary study on the prevalence of Campylobacter in childhood diarrhoea in north Lebanon]

Campylobacter species are a major cause of human diarrhoeal disease worldwide. In Lebanon, the true prevalence of Campylobacter infections and the species distribution in childhood diarrhoea are not known. This study in 2010 investigated the prevalence of Campylobacter species and its possible etiologic role in childhood diarrhoea in north Lebanon. A total of 90 stool samples from children (aged 1 month to 10 years) presenting with diarrhoea were collected from 5 hospitals. A polymerase chain reaction technique (PCR) was used for each sample forthe amplification of all Campylobacter species followed by 5 PCR reactions for the amplification of C. jejuni, C. hyointestinalis, C. coli, C. fetus and C. upsaliensis. Of the 90 samples, 10 were positive for Campylobacterspecies (11.1%):1 for C.coli, 1 for C. jejuni, 2 for both C. jejuni and C. coli, and 6 could not be identified to the species level with the available primers. Campylobacter species is frequently associated with childhood diarrhoea in north Lebanon but Campylobacter infection may be significantly underdiagnosed because the search for Campylobacter is not part of the routine stool culture.

Establishment of human T cell clones exhibiting natural killer-like activity

We have succeeded in establishing a method to reproducibly immortalize human T cells by oncogene(s) transfection (Alam, 1997). This study was based on our previous discoveries that these immortalized T cell lines contained T cells which showed cytotoxicity against K562 cells in MHC-nonrestricted manner. Then we attempted to obtain human T cell clones exhibiting natural killer-like activity. Here, we tried to establish clones from these immortalized T cell lines by limiting dilution after stimulation with K562 cells, and then obtained 16 T cell clones. Two clones among them maintained their stability and showed vigorous growth phenotype. Thus we selected these two clones for further analysis. One is derived from the T cell line transfected with oncogenes ras and fos, the other is from the T cell line transfected with myc and fos. Both clones were demonstrated to be CD4(+) T cells, indicating that CD4(+) T cells were preferably expanded from T cell lines immortalized by oncogene transfection. These two clones showed cytotoxicity against K562 cells, indicating that these two T cell clones still retain a natural killer-like activity of killing target cells of K562 cells in a MHC-nonrestricted manner. The natural killer-like activity of the T cell clones was shown to be stable for more than 2 yr when cultured in the presence of IL-2, indicating that introduction of two oncogenes such as ras/fos or myc/fos resulted in the acquisition of infinite replicative life-span but not in transformational alteration of cellular function.

Functional characterization of human T cells immortalized by oncogene transfection

We have succeeded in immortalizing human lymphocytes derived from the peripheral blood of a healthy donor and of an atopic patient, and from the lymph node of a cancer patient by oncogene transfection (Alam et al., 1996). All immortalized human lymphocytes were shown to be CD3+ and CD19-, indicating that these immortalized human lymphocytes were all T cells. We established 317, 154 and 692 individual immortalized human T cell lines derived from the healthy donor, the atopic patient and the cancer patient, respectively. The ratios of CD4+ and CD8+ subpopulations within the set containing immortalized T cells derived from the healthy donor were shown to be varied depending on the combinations of transfected oncogenes used. However, CD8+ cells were found to be the dominant subpopulation of immortalized T cells derived from the atopic patient and the cancer patient. These immortalized T cells showed different proliferative responses in the presence of exogenous human IL-2 depending on their origin, and was consistent with the surface expression of the IL-2 receptor. Furthermore, the cytokine secretion patterns of these immortalized T cells stimulated with mitogen were investigated. The results showed that the immortalized T cells from the healthy donor is able to secrete various kinds of cytokines such as IL-2, IL-10, β-IFN and GM-CSF. However, immortalized T cells from the cancer patient was shown to only secrete IL-2 and GM-CSF. These results suggest that depending on the origin, the immortalized T cells came from different subsets or from cells in different activated states. Mixed lymphocytes reactions demonstrated that these immortalized T cells are able to proliferate in the presence of allogenic or xenogenic stimulator cells, suggesting that they maintain the ability to recognize specific antigens on the stimulator cells and can proliferate even after the immortalization. Furthermore, immortalized T cells derived from the healthy donor and the cancer patient strongly responded to K562 cells, suggesting that MHC-nonrestricted killer T cells were also immortalized.Abbreviations IL-2R - interleukin 2 receptor; MLR - mixed lymphocyte reaction.

Defining the risk of toxicity in phase I oncology trials of novel molecularly targeted agents: a single centre experience

BACKGROUND

This study defined the risk of serious toxicity in phase I trials of molecularly targeted agents (MTA).

PATIENTS AND METHODS

A retrospective analysis of toxicity data from patients treated in phase I trials of MTAs was carried out to define the rate of treatment-related grade 3/4 toxic effects, deaths and risk factors associated with grade 3 or more toxicity.

RESULTS

Data from 687 patients [median age, 59.1 years (range 12.5-85.5)] treated in 36 trials were analysed. Two hundred and eleven patients were of Eastern Cooperative Oncology Group performance status (PS) zero, 432 of PS one, 38 of PS two and 6 unknown. The rate of grade 3 and 4 events was 14.1% (n=97) and 1.9% (n=13), respectively. Twenty-four percent of events were gastrointestinal, 22% constitutional and 20% metabolic. PS two was associated with a higher risk of toxicity [odds ratio (OR), 2.6; 95% confidence interval (CI) 1.1-6.1; P=0.032] as was receiving >100% of maximum tolerated dose or maximum administered dose (OR 2.5; CI 1.6-3.9; P<0.001). Mortality rate was 0.43% (n=3).

CONCLUSIONS

Therapy with novel MTAs in phase I trials is associated with a moderate risk of significant toxicity. This appears less than in phase I studies involving cytotoxic agents, particularly in relation to grade 4 toxicity. The risk of death is low.

Kynureninase is the conserved self-antigen mimicked by the 2F5 Neutralizing Epitope of HIV-1 gp41 (105.35)

Accumulating evidence suggests that the generation of neutralizing HIV-1 antibody may be proscribed by immunological tolerance. A significant majority of monoclonal human antibodies, including 2F5, that neutralize multiple clades of HIV-1 are polyreactive and bind avidly to unknown components of mammalian cells. Knock-in mice expressing the VH and VL regions of 2F5 are characterized by a central defect in B-cell development that indicates the presence of a tolerizing autoantigen(s) that is mimicked by the membrane-proximal, 2F5 epitope of HIV-1 gp41. If immunological tolerance does indeed prevent regular expression of 2F5-like neutralizing HIV-1 antibody, then discrete autoantigens that structurally mimic the HIV-1 2F5 epitope must be present in those mammalian species unable to make 2F5-like antibody. We now demonstrate that the 2F5 antibody and its unmutated ancestor avidly bind human kynureninase (KYNU), a conserved enzyme of tryptophan metabolism. The H4 domain of most mammalian KYNU contains the complete 2F5 epitope (ELDKWA) of gp41; a H4 mutation of human KYNU to that (ELEKWA) of laboratory opossums resulted in a fully active enzyme completely unreactive with the 2F5 antibody. Immunization of opossums with HIV-1 gp140 induced extraordinary titers of ELDKWA antibody but little or no response to adjacent gp41 epitopes. Identification of an epitope shared by most mammals and HIV-1 provides direct evidence that immunological tolerance can impair humoral responses to HIV-1.

Effect of the HIV nucleoside reverse transcriptase inhibitor zidovudine on the growth and differentiation of primary gingival epithelium

OBJECTIVES

Oral complications associated with HIV infection and with the antiretroviral drugs used to treat it are of increasing concern in HIV-infected patients. Protease inhibitors have been shown to change the proliferation and differentiation state of oral tissues but the effect of nucleoside reverse transcriptase inhibitors is currently unknown. This study examined the effect of zidovudine on the growth and differentiation of the gingival epithelium.

METHODS

Gingival keratinocyte organotypic (raft) cultures were established. The raft cultures were treated with a range of zidovudine concentrations. Haematoxylin and eosin staining was performed to examine the effect of zidovudine on gingival epithelium growth and stratification. Raft cultures were immunohistochemically analysed to determine the effect of this drug on the expression of key differentiation and proliferation markers, including cytokeratins and proliferating cell nuclear antigen (PCNA).

RESULTS

Zidovudine dramatically changed the proliferation and differentiation state of gingival tissues both when it was present throughout the growth period of the tissue and when it was added to established tissue at day 8. Zidovudine treatment increased the expression of cytokeratin 10, PCNA and cyclin A. Conversely, cytokeratin 5, involucrin and cytokeratin 6 expression was decreased. The tissue exhibited characteristics of increased proliferation in the suprabasal layers as well as an increased fragility and an inability to heal itself.

CONCLUSIONS

Zidovudine treatment, even when applied at low concentrations for short periods of time, deregulated the cell cycle/proliferation and differentiation pathways, resulting in abnormal epithelial repair and proliferation. Our system could potentially be developed as a model for studying the effects of HIV and highly active antiretroviral therapy in vitro.

Investigating the Activity of Zirconia as a Catalyst and a Support for Noble Metals, in Green Oxidation of Cyclohexane

Green oxidation of cyclohexane by molecular oxygen was carried out over ZrO2 and noble metals (Pd and Pt) supported on zirconia in solvent free conditions. Studies have been carried out in a typical three-necked batch reactor. Reaction products were identified by GC and UV spectrophotometer. Reaction rates were determined as a function of temperature, partial pressure of oxygen, amount of catalyst, volume of reactants, agitation and reaction duration. The agitation effect and activation energy revealed the absence of mass transfer resistance. Experimental results unveiled the effect of morphology of ZrO2 on catalysis. 1.0 wt.% noble metal/ZrO2(m) was found more selective for cyclohexanol production at low temperature, agitation 900rpm and partial pressure of 101.325 KPa while at high temperature cyclohexanol was further oxidized to cyclohexanone. Comparison of Pt/ZrO2 and Pd/ZrO2 catalysts was made on the basis of reactivity and selectivity. Catalysts were characterized by using BET surface area and pore size analyzer, XRD and SEM. To conclude shortly, for the oxidation of cyclohexane, platinum or palladium supported on zirconia are selective, recyclable and could behave as truly heterogeneous catalysts.