HIV nucleoside reverse transcriptase inhibitors efavirenz and tenofovir change the growth and differentiation of primary gingival epithelium

OBJECTIVES

An increasing number of HIV-infected patients are combating HIV infection through the use of antiretroviral drugs, including reverse transcriptase inhibitors. Oral complications associated with these drugs are becoming a mounting cause for concern. In our previous studies, both protease inhibitors and reverse transcriptase inhibitors have been shown to change the proliferation and differentiation state of oral tissues. This study examined the effect of a nonnucleoside and a nucleoside reverse transcriptase inhibitor on the growth and differentiation of gingival epithelium.

METHODS

Organotypic (raft) cultures of gingival keratinocytes were treated with a range of efavirenz and tenofovir concentrations. Raft cultures were immunohistochemically analysed to determine the effect of these drugs on the expression of key differentiation and proliferation markers, including cytokeratins and proliferating cell nuclear antigen (PCNA).

RESULTS

These drugs dramatically changed the proliferation and differentiation state of gingival tissues when they were present throughout the growth period of the raft tissue as well as when drugs were added to established tissue on day 8. Treatment with the drugs increased the expression of cytokeratin 10 and PCNA and, conversely, decreased expression of cytokeratin 5, involucrin and cytokeratin 6. Gingival tissue exhibited increased proliferation in the suprabasal layers, increased fragility, and an inability to heal itself.

CONCLUSIONS

Our results suggest that efavirenz and tenofovir treatments, even when applied in 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 be developed as a potential model for studying the effects of HIV and highly active antiretroviral therapy (HAART) in vitro.

Microsurgical excision of olfactory groove meningioma's: a brief study of outcome of different surgical approaches

DOI: http://dx.doi.org/10.3329/bmrcb.v39i1.15810Bangladesh Med Res Counc Bull 2013; 39: 45-46

Congenital stenosis in the descending colon causing intestinal obstruction in a one and half years male child

A one and half years male child presented with constipation with severe colicky abdominal pain, bilious vomiting & abdominal distension. He had history of recurrent bouts of constipation followed by gastroenteritis since birth for which he had taken symptomatic treatment & sometimes remained symptom free but he had no other significant history or associated condition. In laboratory investigations, barium enema study of large gut result simulates to Hirschsprung's disease but suction rectal biopsy revealed normal rectal tissue texture. So, consideration of diagnostic tools along with patient's general condition decision was taken for diagnostic laparotomy & peroperatively the child was diagnosed as a case of intestinal obstruction due to congenital colonic stenosis in the descending colon. After resection of stenotic segment and end to end anastomosis, histopathologycal examination of resected stenosed colon was done & it was finally proved as congenital stenosis in the descending colon. The post operative period of the patient was uneventful and he was discharged on 7th postoperative day & followed up upto 6 months. He had been found alright without any complain. Here we tried to high light that the congenital colonic stenosis as a rare, but might be a possible cause of partial/complete intestinal obstruction from newborn to older children in any part of the colon & that should kept in mind for avoiding diagnostic dilemma & proper management of patient.

Investigating the Catalytic Activity of Monoclinic Zirconia; Oxidation of Benzyl Alcohol in Aqueous Medium at Mild Conditions

The oxidation/degradation of benzyl alcohol in artificially contaminated water under atmospheric pressure by molecular oxygen/air over ZrO2(m) catalyst was investigated. Monoclinic phase ZrO2 was synthesized and characterized by modern techniques. Oxidation of benzyl alcohol in aqueous medium was carried out in a typical three necked double walled batch reactor equipped with thermometer and condenser. The rate of oxidation was affected by different reaction parameters such as speed of agitation, catalyst loading, temperature, concentration of substrate solution (46.3 – 185 mmol/L) and partial pressure of oxygen. Major products were detected with GC and UV spectrophotometer. Optimal conditions were setup for better catalytic activity of ZrO2(m). To sum up, catalytic oxidation of benzyl alcohol in aqueous medium by ZrO2(m) is a useful and cheaper method for the conversion of benzyl alcohol to valuable products as well as for the removal of benzyl alcohol from industrial waste water.

Adsorption Studies of Basic Green 4 from Aqueous Solution on Ca2+ Exchanged Clay

The adsorption of basic green 4 from aqueous solution on calcium exchanged clay (Attock-Ca and Swat-Ca) was studied. Clays were first purified and activated with H2SO4 and then exchanged with Ca2+ ions. Clay was characterized by BET surface area, XRD and SEM/EDS. The adsorption kinetic at 298 K and 306 K showed that the first order models were applied to the data. The rate constant increased with the rise in temperature of adsorption/activation. Thermodynamic properties (ΔE≠, ΔH≠, ΔS≠ and ΔG≠) for the adsorption process were calculated. Positive values of ΔH≠ showed that the adsorption of basic green 4 is endothermic. Positive values of ΔS≠ reflected the increase 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's and Langmuir's models described the equilibrium adsorption study and found to fit the experimental data.

Removal of Triphenylmethane Dye from Aqueous Solution by Carbonaceous Adsorbent

Removal of acid blue 1 from aqueous solution on activated carbon produced from Salvadora oleoides was investigated. The samples were characterized by BET surface area, BJH pore volume and pore diameter, XRD, SEM, EDS and FTIR analysis. The surfaces contain functional groups like ketones and hydroxyl which disappeared at high activation temperature; relatively high amount of carbon w.r.t. oxygen was found with the increase in activation temperature; the increase in surface area and development of porous structures showed a positive effect on the adsorption capacity. Adsorption of the dye on carbon at 10 and 45°C showed that the first order, Bangham and Elovich and parabolic diffusion equations apply to the kinetic data. The adsorption rate increased with the temperature and with thermal activation of the sample. Thermodynamic parameters like ΔE≠, ΔH≠, ΔS≠ and ΔG≠ were calculated from the kinetic data. The negative values of ΔS≠ reflect decrease in the disorder of the system at the solid-solution interface during adsorption. Gibbs free energy (ΔG≠), which represents the driving force for the affinity of dye for the carbon, increased with the increase in activation temperature.

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.