Preparation and evaluation of cytotoxic potential of paclitaxel containing poly-3-hydroxybutyrate-co-3-hydroxyvalarate (PTX/PHBV) nanoparticles

Paclitaxel (PTX) is a potent anticancer drug. In the present study, PTX was loaded in poly-3-hydroxybutyrate-co-3-hydroxyvalarate (PHBV) to fabricate the PTX/PHBV (drug-loaded) nanoparticles via the nanoprecipitation method. Blank PHBV nanoparticles were also prepared. The drug-encapsulation efficiency of PTX/PHBV nanoparticles was 45±0.4%. The PTX/PHBV nanoparticles exhibited a pH-sensitive release profile and followed a quasi-Fickian diffusion mechanism. Cytotoxic properties of PHBV and PTX/PHBV nanoparticles were checked against the MCF-7 and Caco-2 cell lines. The PHBV nanoparticle did not inhibit the proliferation of MCF-7 and Caco-2 cell lines, thus depicting their non-toxic and biocompatible nature. On the other hand, the PTX/PHBV nanoparticles demonstrated 1.03-fold higher cytotoxicity and 1.61-fold enhanced apoptosis after treatment with the PTX/PHBV nanoparticles versus free PTX. In summary, the PHBV nanoparticles could be a potential candidate for the delivery of PTX for cancer treatment.

Identification of hemodynamically significant coronary artery disease with stress myocardial blood flow ratio by dynamic CT perfusion studies

Funding Acknowledgements

Type of funding sources: None.

Introduction

Coronary computed tomographic angiography (CTA) is an accepted noninvasive tool with high diagnostic accuracy for the evaluation of coronary artery disease (CAD). However, coronary CTA is limited in that it does not provide information on the hemodynamic relevance of coronary artery stenosis. Therefore, to determine the potential benefit of future coronary revascularization, a functional assessment is often required. A protocol combining coronary computed tomographic angiography (CTA) and CTP can provide a simultaneous assessment of both coronary artery ischemia and anatomy.

Purpose

This study sought to evaluate the diagnostic accuracy of stress myocardial blood flow ratio (SFR), a novel parameter derived from stress dynamic computed tomographic perfusion (CTP), for the detection of hemodynamically significant coronary stenosis.

Methods

A total of 98 patients (mean age 54.5 ± 10 years) with 128 vessels with either 1- or 2-vessel disease, scheduled for invasive angiography were included in this study. Stress dynamic CTP was performed followed by coronary CTA using a dual-source computed tomographic system. Fractional flow reserve was performed at subsequent invasive angiography to identify hemodynamically significant stenosis. Stress myocardial blood flow ratio (SFR) was defined as the ratio of hyperemic myocardial blood flow (MBF) in an artery with stenosis to hyperemic MBF in a non-diseased artery. The diagnostic accuracy of the SFR index was determined against the reference standard of invasive fractional flow reserve ≤0.80.

Results

58 (45.3%) vessels were deemed hemodynamically significant by fractional flow reserve (FFR) measurement. Hyperemic MBF and SFR were lower for vessels with hemodynamically significant lesions (95 ± 32.2 ml/100 ml/min vs. 140.5 ± 30.4 ml/100 ml/min; p < 0.01 for both). When compared with ≥50% stenosis by CTA, the specificity for detecting ischemia by SFR increased from 44% to 92%, while the sensitivity decreased from 93% to 58%. The combination of stenosis ≥50% by CTA and SFR resulted in an area under the curve of 0.9, which was significantly higher compared with hyperemic MBF, area under the curve = 0.79 and p < 0.01.

Conclusion

Our study concludes that the calculation of SFR by dynamic CTP provides a pioneering and accurate method to identify flow-limiting coronary stenosis. Abstract Figure.

Pharmacological evaluation of the use of dexrazoxane in preventing anthracycline induced cardiotoxicity in breast cancer

Funding Acknowledgements

Type of funding sources: None.

Background

Anthracyclines and trastuzumab are extensively used for the treatment of breast cancer but are associated with an increased risk of dilated cardiomyopathy. Dexrazoxane is an iron-chelating agent used to reduce the risk of cardiotoxicity, but it is seldom used in clinical practice.

Purpose

A meta-analysis was performed to check the efficacy of dexrazoxane in patients with breast cancer who were treated with anthracyclines with or without trastuzumab.

Methods

Online databases were searched from January 2000 up to October 31, 2019, for clinical trials on the use of dexrazoxane for the prevention of cardiomyopathy in patients with breast cancer receiving anthracyclines with or without trastuzumab. Risk ratios with 95% confidence intervals were calculated using a mixed-effects model meta-analysis.

Results

Five randomized trials and 2 retrospective trials with a total of 1,587 patients were included. Dexrazoxane reduced the risk of clinical heart failure (p < 0.001) and cardiomyopathy (p < 0.001) irrespective of previous exposure to anthracyclines. The overall survival rate, progression-free survival and the rate of partial or complete oncological response were not affected by dexrazoxane.

Conclusion

Our study concludes that dexrazoxane reduced the risk of heart failure and cardiomyopathy in the patients who were treated with anthracycline chemotherapy with or without trastuzumab and did not impact cancer outcomes significantly. However, the area of our study is limited and further studies should be done before the systematic application of this therapy in clinical practice. Abstract Figure.

Antibiotic Resistance in Diarrheagenic Escherichia coli Isolated from Broiler Chickens in Pakistan

Background: Diarrheagenic Escherichia coli (DEC) strains are predominant cause of gastrointestinal tract illnesses. The main objective of the study was to determine antibiotic resistance in various types of DEC isolated from chicken broilers farmed in Pakistan. Methods: A total of 200 feces and 200 meat samples from broiler chickens were collected from the slaughtering shops in Southern Punjab, Pakistan. The confirmed fecal (n=150) and meat (n=150) E. coli isolates were investigated against 16 antibiotics. Fourteen virulence genes specific for Enteropathogenic (EPEC), Shiga Toxin-producing (STEC), Enteroinvasive (EIEC), Enteroaggregative (EAEC), and Enterotoxigenic (ETEC) E. coli were identified using Polymerase Chain Reaction. Results: EPEC was the most detected pathotype in both feces (76%) and meat (90%) samples, followed by STEC, EIEC, and ETEC. The highest resistance (40-90%) was observed against penicillin, oxytetracycline, and nalidixic acid in fecal isolates. More than 50% EPEC and EAEC fecal isolates, and 60% EAEC meat isolates were simultaneously resistant to 6 or more antibiotics. Conclusion: Conclusively, the broiler meat sold in open markets of Pakistan was considerably contaminated with multi-drug resistant DEC. To mitigate the issue, the gov- ernment should regulate the use of antibiotics at poultry farms and monitor slaughtering practices in slaughterer houses.

Synthesis, characterization and photocatalytic performance of W6+ impregnated g-C3N4 for the removal of chlorophenol derivatives in natural sunlight exposure

The surface of the g-C₃N₄ was altered by impregnating W⁶⁺ ions that transformed to homogeneously coated oxide layer by a calcination process. An enhanced absorption and the suppressed de-excitation in the emission spectra, with the increasing W⁶⁺ loading, exposed the supporting role of the coated layer in extending the spectral response as well as the prolonged life span of excitons. The same was further supported by electrochemical impedance spectroscopy (EIS). The XRD and XPS analysis revealed the coated layer as highly crystalline pure phase monoclinic WO₃ with the majority of impregnated tungsten ions in 6+ oxidation state respectively, whereas the FESEM and HRTEM analysis substantiated the uniformity of the coated layer with the interlayer spacing of the 0.369 nm. Additionally, the probable formation of individual WO₃ nanoparticles or clusters was ruled out. The as-synthesized impregnated photocatalysts, in comparison to pure g-C₃N_4, were subjected to natural sunlight exposure for the photocatalytic removal of chlorophenol derivatives (2-CP, 3-CP, 4-CP, 2,3-DCP, 2,4-DCP, 2,4,6-TCP and PCP) that revealed the 5 wt% coating as the optimum level for significant removal. The progress of the photocatalytic process was monitored by periodic HPLC analysis whereas ion chromatography (IC) was used for the estimation of released ions. The mineralization capability of the as-synthesized W⁶⁺ coated catalysts was measured by the time scale TOC measurements. As the formation of intermediates was indicated in HPLC analysis, selected samples were subjected to GC-MS analysis for the identification of the nature of intermediates. The variable degree of removal of chlorophenol derivatives signified the role of the position and orientation of Cl group. The kinetics of the removal process was evaluated with the calculation of rate constants. The results extracted from the analytical tools and the associated band edge potentials were correlated to speculate the probable mechanism as well as the identification of major reactive oxygen species (ROS) involved in the removal process.

The efficacy of Co3O4 loaded WO3 sheets for the enhanced photocatalytic removal of 2,4,6-trichlorophenol in natural sunlight exposure

Owing to the promising photocatalytic performance, the sheet-like WO₃ was modified by depositing nanostructured Co₃O₄ at the surface. The appearance of the varying dual absorption edges in the optical analysis exposed the composite nature of the synthesized materials. The structural analysis revealed the deposition of Co₃O₄ particles at the surface without altering the lattice of WO₃ however, during the processing the cracking of disc was also evidenced. The FESEM and HRTEM analysis corroborated the uniform surface dispersion of Co₃O₄ nanoparticles. The co-existence of 2+ and 3+ oxidation states of Co in the deposited Co₃O₄ was examined by XPS analysis. The efficient trapping of excitons by Co₃O₄ surface entities was witnessed in the emission measurements whereas the same was authenticated by the photo-electrochemical chronopotentiometry. The Co₃O₄ loaded sheets exhibited substantially enhanced activity for the removal of 2,4,6-trichlorophenol as compared to pure WO₃ in the complete spectrum and visible region of natural sunlight exposure. The progress of the degradation process was monitored by HPLC whereas the degradation products were identified by GC-MS. The measurement and identification of the ion released during the photocatalytic process facilitated the estimation of the probable route and role of reactive oxygen species involved in the removal process. Although, the careful analysis of the findings from the analytical tools revealed the major involvement of hydroxyl radicals however, the role of superoxide anions was also exposed. An alternative mechanism of the generation of the superoxide radical involving the 2+ and 3+ oxidation states of Co was also proposed. The effect of the pH and the added concentration of H₂O₂ on the ease of removal process was also investigated.

Deletions of the Idh1, Eco1, Rom2, and Taf10 Genes Differently Control the Hyphal Growth, Drug Tolerance, and Virulence of Candida albicans

The most recent genome-editing system called CRISPR-Cas9 (clustered regularly interspaced short palindromic repeat system with associated protein 9-nuclease) was employed to delete four non-essential genes (i.e., Caeco1, Caidh1, Carom2, and Cataf10) individually to establish their gene functionality annotations in pathogen Candida albicans. The biological roles of these genes were investigated with respect to the cell wall integrity and biogenesis, calcium/calcineurin pathways, susceptibility of mutants towards temperature, drugs and salts. All the mutants showed increased vulnerability compared to the wild-type background strain towards the cell wall-perturbing agents, (antifungal) drugs and salts. All the mutants also exhibited repressed and defective hyphal growth and smaller colony size than control CA14. The cell cycle of all the mutants decreased enormously except for those with Carom2 deletion. The budding index and budding size also increased for all mutants with altered bud shape. The disposition of the mutants towards cell wall-perturbing enzymes disclosed lower survival and more rapid cell wall lysis events than in wild types. The pathogenicity and virulence of the mutants was checked by adhesion assay, and strains lacking rom2 and eco1 were found to possess the least adhesion capacity, which is synonymous to their decreased pathogenicity and virulence.

Maintenance of photosynthesis and the antioxidant defence systems have key roles for survival of Halopeplis perfoliata (Amaranthaceae) in a saline environment

Coastal salt marsh plants employ various combinations of morphological and physiological adaptations to survive under saline conditions. Little information is available on salinity tolerance mechanisms of Halopeplis perfoliata, a C3 stem succulent halophyte. We investigated the growth, photosynthesis and antioxidant defence mechanisms of H. perfoliata under saline conditions (0, 150, 300 and 600 mM NaCl) in an open greenhouse. Optimal shoot succulence, projected shoot area and relative growth rate were obtained in the low (150 mm NaCl) salinity treatment, while growth was inhibited at the highest salinity (600 mm NaCl). The CO₂ compensation point and carbon isotope composition of biomass confirmed C₃ photosynthesis. Increases in salinity did not affect the photosynthetic pigment content or maximum quantum efficiency of PSII of H. perfoliata. Assimilation of CO₂ (A) also remained unaffected by salinity. A modest effect on some gas exchange and photochemistry parameters was observed at 600 mm NaCl. With increasing salinity, there was a continual increase in respiration, suggesting utilisation of energy to cope with saline conditions. Under 300 and 600 mm NaCl, there was an increase in H₂ O₂ and MDA with a concomitant rise in AsA, GR content and CAT activity. Hence, H. perfoliata appears to be an obligate halophyte that can grow up to seawater salinities by modulating photosynthetic gas exchange, photochemistry and the antioxidant defence systems.

Improvement in Infection Prevention and Control Measures at The Children Hospital, Lahore. A My Child Matters Collaborative Project

Background: Overcrowding, lack of operational funds, and healthcare associated infections are major challenges at the Children Hospital Lahore, a public healthcare facility in Pakistan with 900 new pediatric cancer admissions annually. In 2014, a collaboration between My Child Matters (MCM), St. Jude Global Infectious Diseases Program (SJ-GID), and our institution was established to address these issues. Aim: To describe the effect of a collaborative improvement strategy on the infection prevention and control (IPC) standards in a pediatric oncology unit in a resource-limited setting. Methods: Our study was a prospective before-and-after study. We compare the WHO Hand Hygiene Self-Assessment Framework (HHSAF) and 4 modules of the St. Jude modified Infection Control Assessment Tool (ICAT) scores. Our strategy included: (1) creating a multidisciplinary team of pediatric hematology-oncology, infectious disease physicians, nurses, microbiologist, and a data manager, (2) engaging on monthly online IPC mentoring sessions with the SJ-GID and MCM mentors, (3) performing daily inpatient healthcare associated (HAI) surveillance rounds, and (4) providing regular hand hygiene training and compliance audits. Results: Our hand hygiene facility level per WHO scores increased from “Inadequate” during the baseline assessment to “Intermediate/Consolidation” by the end of 3-year implementation (122 vs 352 HHSAF scores). The sink: bed and hand sanitizer: bed ratios improved to 1:6 and 1:1 respectively. Six washrooms were added to our unit. ICAT general infection control module increased by 40% (45 vs 78 ICAT score) and hygiene compliance improved by 20% from baseline. Identification of HAI increased from baseline (4.07 vs 8.7 infections per 1000 patient days). A 25% of the isolates were multidrug-resistant microorganisms. Conclusion: Implementing a collaborative improvement strategy improved the IPC standards in our pediatric cancer center. The increase of HAI might be a result of a better surveillance and laboratory identification. Further targeted interventions should be develop to decrease HAI rates and infection-related morbidity and mortality in our population.

Evaluation of SnO2 for sunlight photocatalytic decontamination of water

The broad bandgap tin (IV) oxide (SnO₂) is the least investigated semiconductor material for photocatalytic water decontamination in sunlight exposure. A detailed study covering the synthesis, characterization and the evaluation of photocatalytic activity of SnO₂, in the natural sunlight exposure, is presented. The structural characterization by XRD revealed the formation of phase pure tetragonal SnO₂ with the average crystallite size of ∼41.5 nm whereas minor Sn²⁺ states in the material were identified by XPS analysis. As explored by diffuse reflectance (DR) and photoluminescence (PL) spectroscopy, the material exhibited a distinct absorption edge at ∼3.4 eV. The morphological and microstructure analysis of the synthesized SnO₂ was carried out by FESEM and HRTEM. The electrochemical impedance spectroscopy (EIS) and chronopotentiometry (CP) predicted the better charge transport and retention ability of the material under illumination whereas the Mott-Schottky extrapolation prophesied the n-type behavior with the flat-band potential of -0.60 V. The photocatalytic activity of SnO₂ was assessed in the exposure of complete spectrum natural sunlight for the removal of 2,4,6-trichlorophenol. The HPLC and TOC analysis monitored the progress of degradation and mineralization whereas the released chloride ions were evaluated by ion chromatography. The effect of the transition metal ions (Fe³⁺, Cu²⁺, Ni^2+, and Zn²⁺) as electron capture agents and H₂O₂ as ROS generator was explored during the degradation process. The utility of the material for the simultaneous removal of chlorophenols in the mixture was also investigated. The SnO₂ exhibited sustained activity in the repeated use. Based on experimental evidence congregated, the mechanism of the removal process and the efficacy of SnO₂ for sunlight photocatalytic decontamination of water was established.

On differences in the equation-of-state for a selection of seven representative mammalian tissue analogue materials

Tissue analogues employed for ballistic purposes are often monolithic in nature, e.g. ballistic gelatin and soap, etc. However, such constructs are not representative of real-world biological systems. Further, ethical considerations limit the ability to test with real-world tissues. This means that availability and understanding of accurate tissue simulants is of key importance. Here, the shock response of a wide range of ballistic simulants (ranging from dermal (protective/bulk) through to skeletal simulant materials) determined via plate-impact experiments are discussed, with a particular focus on the classification of the behaviour of differing simulants into groups that exhibit a similar response under high strain-rate loading. Resultant Hugoniot equation-of-state data (U_s-u_p; P-v) provides appropriate feedstock materials data for future hydrocode simulations of ballistic impact events.

Flooding adds pathogenic Escherichia coli strains to the water sources in southern Khyber Pakhtunkhwa, Pakistan

PURPOSE

Seasonal rains in Pakistan result in heavy floods across the country, whereby faecal contaminants will be added to the water bodies and cause numerous food-borne outbreaks. The present study was aimed to determine the prevalence of diarrheagenic Escherichia coli (DEC) strains in the water sources.

MATERIALS AND METHODS

Two hundred water samples collected during (2011-2012) were processed for the isolation of E. coli (EC) strains. EC strains were further analysed for antibiotic susceptibility patterns, and pathogroups-specific virulence factors stx1, stx2, stx2c, eae, tir, hlyA, bfpA, estA and eltA were detected using multiplex polymerase chain reaction.

RESULTS

Thirty-three percent of the water samples were contaminated with EC pathotypes. Fifty percent (33/66) of the DEC pathotypes were identified as enterotoxigenic EC (ETEC). Seventy-two percent (13/18) of the enteropathogenic EC (EPEC) strains were identified as typical EPEC and 28% (5/18) as atypical EPEC. Eleven percent (7/66) of the Shiga toxin EC (STEC) isolates carried a combination of stx1 and stx2 genes. Summer was found as a peak season with 47% (31/66) for EC pathogroups' activities. Eighty-nine percent of the strains showed resistance against tetracycline.

CONCLUSION

ETEC and EPEC are the primary causes of water contamination in southern regions of Khyber Pakhtunkhwa province, Pakistan. Firm adherence to the prescribed drugs can decrease trends in antibiotic resistance.

Photocatalytic activity of V doped ZnO nanoparticles thin films for the removal of 2- chlorophenol from the aquatic environment under natural sunlight exposure

Vanadium doped ZnO powders were used as precursors to deposit thin films of V(5+) incorporated ZnO nanoparticles on glass substrates by the pulsed laser deposition technique. The observed variations in Raman signals, visible region shift in the diffuse reflectance spectra along with a small shift in the (101) reflections of the X-ray diffraction (XRD) confirmed the insertion of V(5+) ions in ZnO lattice. No other additional reflection in the XRD results other than ZnO further endorsed the occupation of lattice positions by V entities rather than independent oxide formation. The asymmetric XPS peaks of Zn2p and V2p core levels confirmed the existence of both in the vicinity. The existence of minimal proportion of V(3+) along with V(5+) states varied the alteration of the oxidation states V in the synthetic route. The SEM images at various resolutions displayed the uniform distribution identical nanoparticles without the presence of additional phases in the deposited films. The SEM cross-section measurements revealed the uniform thickness of ∼90 nm of each film, whereas the surface studies of the films were performed by AFM. The as-synthesized films were tested for photocatalytic activity in sunlight illumination for the removal of 2-chlorophenol. The unique feature of the study was the estimation of the photocatalytic activity 20 ppm of 2-chlorophenol by exposing the low exposed area. The degradation of the substrate was measured by liquid phase UV-vis spectroscopy, whereas total organic carbon measurement revealed the mineralization of the substrate. The released Cl(-) ions were also measured by ion chromatography. The estimated flatband potentials and pHzpc values of the V doped materials, by Mott-Schottky analysis and zeta potential measurements respectively, were correlated with the photocatalytic activity. The kinetics of the photocatalytic degradation/mineralization process was estimated and results were correlated with the plausible mechanism.

Gene mapping in an anophthalmic pedigree of a consanguineous Pakistani family opened new horizons for research

Clinical anophthalmia is a rare inherited disease of the eye and phenotype refers to the absence of ocular tissue in the orbit of eye. Patients may have unilateral or bilateral anophthalmia, and generally have short palpebral fissures and small orbits. Anophthalmia may be isolated or associated with a broader syndrome and may have genetic or environmental causes. However, genetic cause has been defined in only a small proportion of cases, therefore, a consanguineous Pakistani family of the Pashtoon ethnic group, with isolated clinical anophthalmia was investigated using linkage mapping. A family pedigree was created to trace the possible mode of inheritance of the disease. Blood samples were collected from affected as well as normal members of this family, and screened for disease-associated mutations. This family was analyzed for linkage to all the known loci of clinical anophthalmia, using microsatellite short tandem repeat (STR) markers. Direct sequencing was performed to find out disease-associated mutations in the candidate gene. This family with isolated clinical anophthalmia, was mapped to the SOX2 gene that is located at chromosome 3q26.3-q27. However, on exonic and regulatory regions mutation screening of the SOX2 gene, the disease-associated mutation was not identified. It showed that another gene responsible for development of the eye might be present at chromosome 3q26.3-q27 and needs to be identified and screened for the disease-associated mutation in this family.

The effect of cerium alteration on the photocatalytic performance of WO3 in sunlight exposure for water decontamination

In an effort to enhance the photocatalytic activity of cubic WO₃ in sunlight exposure, its surface was modified by impregnating the Ce³⁺ ions ranging from 1% to 25% with a step of 5% with respect to the weight of WO₃.

Synthesis, Characterization, and Sunlight Mediated Photocatalytic Activity of CuO Coated ZnO for the Removal of Nitrophenols

CuO@ZnO core-shell catalysts, coated by varying the CuO layer density ranging from 0.5% to 10%, were synthesized with the aim to enhance the photocatalytic activity of ZnO in sunlight and control its photocorrosion. Initially, the Cu(2+) ions were impregnated on presynthesized ZnO by wet impregnation and finally converted to CuO layers by calcination. The optical and structural characterization of the synthesized powders was performed by DRS, PL, Raman spectroscopy, and XRD analysis, respectively. The homogeneity of the coated layers was explored by FESEM. The photocatalytic activity of CuO coated ZnO was investigated for the degradation of mononitrophenols (2-, 3-, and 4-nitrophenol) and dinitrophenols (2,4-, 2,5-, and 2,6-dinitrophenol) in the exposure of the complete spectrum and visible region (420-800 nm) of sunlight. The effect of the increasing density coated layers of CuO on photocatalytic activity was evaluated for the degradation of 4-NP. Compared to pristine ZnO, a substantial increase in the degradation/mineralization ability was observable for the catalysts coated with 0.5% and 1% CuO, whereas a detrimental effect was noticed for higher coating density. Prior to photocatalytic studies, as evaluated by cyclic voltammetry (CV), compared to pure ZnO, a significant suppression of photocorrosion was noticed, under illumination, for catalysts coated with lower CuO coating. The progress of the photocatalytic degradation process was monitored by HPLC while the mineralization ability of the synthesized catalysts was estimated by TOC. The estimation of the released ions and their further interaction with the excited states and the reactive oxygen was monitored by ion chromatography (IC).

Evaluation of sunlight induced structural changes and their effect on the photocatalytic activity of V2O5 for the degradation of phenols

Despite knowing the fact that vanadium pentoxide is slightly soluble in aqueous medium, its photocatalytic activity was evaluated for the degradation of phenol and its derivatives (2-hydroxyphenol, 2-chlorophenol, 2-aminophenol and 2-nitrophenol) in natural sunlight exposure. The prime objective of the study was to differentiate between the homogeneous and heterogeneous photocatalysis incurred by dissolved and undissolved V2O5 in natural sunlight exposure. V2O5 was synthesized by chemical precipitation procedure using Triton X-100 as morphology mediator and characterized by DRS, PLS, Raman, FESEM and XRD. A lower solubility of ∼ 5% per 100ml of water at 23 °C was observed after calcination at 600 °C. The study revealed no contribution of the dissolved V2O5 in the photocatalytic process. In sunlight exposure, V2O5 powder exhibited substantial activity for the degradation, however, a low mineralization of phenolic substrates was observed. The initial low activity of V2O5 followed by a sharp increase both in degradation and mineralization in complete spectrum sunlight exposure, was further investigated that revealed the decrease in the bandgap and the reduction in the particle size with the interaction of UV photons (<420 nm) as this effect was not observable in the exposure of visible region of sunlight. The role of the chemically different substituents attached to an aromatic ring at 2-positions and the secondary interaction of released ions during the degradation process with the reactive oxygen species (ROS) was also explored.

Genetic association analysis of serotonin transporter polymorphism (5-HTTLPR) with type 2 diabetes patients of Pakistani population

AIMS

It is well established that the serotonergic system contributes to the regulation of glucose homeostasis and feeding and therefore it has been presumed to contribute to the biological susceptibility to type 2 diabetes mellitus (T2DM) and body-mass index (BMI). 5-HTTLPR is a serotonin transporter (5-HTT) gene-linked polymorphic region that regulates the transcriptional activity of 5-HTT. Our aim was to investigate the possible association of 5-HTTLPR polymorphism (L and S alleles) in the promoter region of the serotonin transporter gene with T2DM and/or higher BMI in Pakistani population.

METHODS

In this study, 574 subjects diagnosed with T2DM and 402 unrelated normal controls from the general Pakistani population were genotyped for 5-HTTLPR polymorphism by PCR amplification and agarose gel electrophoresis. The genotyping data (S/S, S/L and L/L) were recorded and analysed statistically using various software and online available tools.

RESULTS

In the total sample, patients with type 2 diabetes and controls without diabetes, genotypes were distributed according to Hardy-Weinberg equilibrium, and S allele frequency was 61.52% (0.61). There was no statistical association between 5-HTTLPR polymorphism and the development of T2DM in this Pakistani population (p=0.12).

CONCLUSIONS

No significant statistical association of 5-HTTLPR polymorphism with type 2 diabetes and obesity in Pakistani population shows that 5-HTTLPR polymorphism is not a major factor in determining type 2 diabetes and obesity in Pakistan.

The facile synthesis, characterization and evaluation of photocatalytic activity of bimetallic FeBiO3 in natural sunlight exposure

In an effort to develop sunlight active photocatalysts for environmental remediation, a phase pure bimetallic oxide, FeBiO₃, was synthesized by a facile route.

Synthesis, characterization and visible light photocatalytic activity of Cr3+, Ce3+and N co-doped TiO2for the degradation of humic acid

The synthesis, characterization and photocatalytic activity of Cr³⁺and Ce³⁺co-doped TiON (N-doped TiO₂) for the degradation of humic acid with exposure to visible light is reported.

Enhanced photocatalytic activity of V₂O₅-ZnO composites for the mineralization of nitrophenols

In an effort to enhance the photocatalytic activity of ZnO in natural sunlight, V2O5-ZnO nanocomposites were synthesized by co-precipitation technique. The characterization of the synthesized powders by FESEM, XRD and UV-visible diffuse reflectance spectroscopy (DRS) revealed that the both V2O5 and ZnO retain their individual identity in the composites but the increasing concentration of V2O5 affect the particle size of ZnO. As estimated by photoluminescence spectroscopy, in comparison to pure ZnO, the presence of V2O5 significantly suppressed the charge carrier's recombination process. The photocatalytic activity of the synthesized powders was evaluated for the degradation/mineralization of three potential nitrophenol pollutants (2-nitrophenol, 4-nitrophenol, and 2,4-dinitrophenol). The synthesized composites showed significantly higher activity for both degradation and mineralization of nitrophenols compared to pure ZnO. The progress of the degradation process was evaluated by HPLC while mineralization was monitored by TOC analysis. The degradation/mineralization route was estimated by identifying the intermediates using GC-MS. The correlation of the experimental data revealed that the position of NO2 group in 2- and 4-nitrophenol significantly affect the rate of degradation. The identification of hydroxyl group containing intermediates in the degradation of 4-NP confirmed the formation and vital role of hydroxyl radicals in degradation process. The rapid mineralization of nitrophenol substrates pointed out superoxide anions as major contributors in degradation and mineralization process. The assessment of the release of relevant ions (NO2(-), NO3(-), ONOO(-) and NH4(+)) during the degradation process assisted in identifying the plausible interaction sites.

Morphology controlled bulk synthesis of disc-shaped WO3 powder and evaluation of its photocatalytic activity for the degradation of phenols

The surfactant assisted synthesis of disc-shaped WO3 powder and its photocatalytic performance in sunlight exposure is reported. UV-vis DRS, XRD and FESEM characterized the synthesized WO3. The synthesized powder exhibited a bandgap of ∼2.55eV with cubic lattice and high crystallinity. The photocatalytic activity of the synthesized WO3 was examined for the degradation of phenol, resorcinol, 2-chlorophenol and 2-nitrophenol in complete spectrum and visible segment of sunlight. The highly efficient degradation/mineralization of 2-chloro and 2-nitrophenol compared to that of phenol and resorcinol, under identical experimental conditions, suggested the regulatory role of substituents attached to the aromatic ring in degradation/mineralization process. The time-scale HPLC degradation profiles, identification of intermediates by GC-MS and removal of organic carbon during the course of reaction were utilized to approximate the possible route of degradation/mineralization of phenolic substrates. The measurement of the anions released during the photocatalytic process was used to identify the nature of the major oxidants (O2(•-), OH(•)) and the possible interaction sites. A significant decrease in the photocatalytic activity of synthesized WO3, ∼50%, was observed in visible portion of sunlight however, a sustained activity was observed in the repeated exposures.

Novel p53 codon 240 Ser > Thr coding region mutation in the patients of oral squamous cell carcinoma (OSCC)

Chewing habits of tobacco, betel quid (paan), and betel nut (chhaliya) are common traditions in Pakistan. Different other preparations and combination of flavors with tobacco, paan, and chhaliya ingredients are commonly available in the market and have received considerable attention as sources of carcinogens that promote OSCC. Mutagens can damage DNA and generate promutagenic lesions. The germ line mutation/polymorphism of p53 gene has been reported to be involved in multiple steps of carcinogenesis. This study aims to find out the loss of TP53 functions due to mutation/polymorphism caused by genomic alteration and interaction with tobacco-related ingredients.Tissue and blood specimens from 260 OSCC patients were collected and compared with blood samples of 260 age- and sex-matched controls. Mutations in exons 2-11 of p53 gene were examined by PCR-SSCP and directly sequenced.A novel mutation was found in exon 7 of p53 gene. This mutation was observed in the tumors of the OSCC patients. The blood samples of the patients and the controls did not show the nucleotide change in this region. The "AGT" to "ACT" missense mutation was identified at position 719 at TP53. This results in the substitution of amino acid serine with threonine at codon 240 of p53 protein.This novel missence mutation in the DNA-binding domain indicated that the DNA structure may be damaged by the use of exogenous DNA-damaging agents, including tobacco-related carcinogens present in gutka, niswar, and manpuri, which may result in the loss of p53 protein function.

Synthesis, characterization and photocatalytic activity of Al₂O₃-TiO₂ based composites

The synthesis, characterization and photocatalytic performance of non-traditional Al₂O₃-TiO₂-based photocatalysts is reported. Al₂O₃-TiO₂ support was loaded with various fractions of CuO and ZrO₂. A sound agreement was observed between the bandgaps of synthesized powders measured by UV-Visible diffuse reflectance spectroscopy (DRS) in the solid phase and UV-Visible spectroscopy in the aqueous medium. X-ray diffraction (XRD) analysis revealed the composite nature of the catalysts with the retention of individual identity of each component. The average crystallite size of the individual component was found to be in the range of 20 to 40 nm. Scanning electron microscopy (SEM) analysis authenticated the presence of CuO and ZrO₂ at the surface of Al₂O₃-TiO₂ support, while Rutherford Back Scattering Spectroscopy (RBS) confirmed the quantity of the modifiers as per theoretical calculations. The composites showed an enhanced photocatalytic activity in sunlight compared to Al₂O₃-TiO₂ for the degradation of dyes. Efforts were made to elucidate the enhanced sunlight response of the synthesized composite catalysts compared to Al₂O₃-TiO₂. As monitored by ion chromatography (IC), the synthesized photocatalysts completely mineralized the dyes leaving behind inorganic ions in solution. The kinetics of photocatalytic degradation of dyes was evaluated for optimum correlation with the existing models. The stability of the photocatalysts against the photo-corrosion was monitored by analyzing the samples for respective metals in solution after sunlight exposure. Supplemental materials are available for this article. Go to the publisher's online edition of the Journal of Environmental Science and Health, Part A, to view the supplemental file.

Ce3+ impregnated ZnO: a highly efficient photocatalyst for sunlight mediated mineralization

The surface of pre-synthesized hexagonal ZnO was tailored by Ce³⁺ states.

The high strain-rate behaviour of selected tissue analogues

The high strain-rate response of four readily available tissue simulants has been investigated via plate-impact experiments. Comparison of the shock response of gelatin, ballistic soap (both sub-dermal tissue simulants), lard (adipose layers) and Sylgard(®) (a potential brain simulant) allowed interrogation of the applicability of such monolithic tissue surrogates in the ballistic regime. The gelatin and lard exhibited classic linear Hugoniot equations-of-state in the US-uP plane; while for the ballistic soap and Sylgard(®) a polymer-like non-linear response was observed. In the P/σX-v/v0 plane there was evidence of separation of the simulant materials into distinct groups, suggesting that a single tissue simulant is inadequate to ensure a high-fidelity description of the high strain-rate response of complex mammalian tissue. Gelatin appeared to behave broadly hydrodynamically, while soap, lard and Sylgard(®) were observed to strengthen in a material-dependent manner under specific loading conditions at elevated shock loading pressures/stresses. This strengthening behaviour was tentatively attributed to a further polymeric-like response in the form of a re-arrangement of the molecular chains under loading (a steric effect). In addition, investigation of lateral stress data from the literature showed evidence of operation of a material-independent strengthening mechanism when these materials were stressed above 2.5-3.0GPa, tentatively linked to the generically polymeric-like underlying microstructure of the simulants under consideration.

Production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) depolymerase from Aspergillus sp. NA-25

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) degrading thermophilic fungus was isolated from soil sample collected from waste disposal site, Islamabad, Pakistan. It was able to grow efficiently on a medium containing PHBV as a sole source of carbon and has been identified as Aspergillus sp. NA-25 by 18S rRNA. Using 9% of inoculum maximum production of PHBV depolymerase was observed at 45 degrees C, pH 7.0 in the presence of 0.2% lactose as an additional carbon source. PHBV depolymerase was purified by precipitation with 80% ammonium sulfate and gel filtration chromatography on Sephadex G-75. The four enzyme forms obtained after gel filtration were analyzed on SDS-PAGE and their molecular weights (36, 68, 72 and 90 kDa) were determined. They were characterized on the basis of effect of different temperatures, pH, metal ions and different reagents on the PHBV activity and stability. It is obvious that the fungal strain Aspergillus sp. NA-25 is capable of degrading PHBV with the help of different types of depolymerases.

Degradation of polyisoprene rubber by newly isolated Bacillus sp. AF-666 from soil

Various microorganisms were screened for their ability to degrade polyisoprene rubber (natural rubber latex gloves). Strain AF-666, newly isolated from a soil sample, was selected as the best strain having the ability to grow on polyisoprene containing plates. The strain identified as Bacillus sp. AF-666, was found to degrade polyisoprene rubber, both on basal agar plates (latex overlay) as well as in liquid medium. Qualitative analysis of degradation was done through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy SEM showed changes in surface morphology, like appearance of pits and cracks, and marked difference in transmittance spectra of test and control due to changes in the functional groups, was detected through FTIR. CO2 evolution as a result of rubber degradation, was calculated gravimetrically by Sturm Test. About 4.43 g/1 of CO2 was produced in case of test, whereas, 1.57 g/1 in case of control. The viable number of cells (CFU/ml) was also higher in test than in control. Present study may provide an opportunity for further studies on the applications of biotechnological processes as a tool for rubber waste management.

Sero-epidemiology of peste des petits ruminants (PPR) in Pakistan

A sero survey was conducted during 2005-2006 to estimate the sero prevalence of PPR in the small ruminant population of Pakistan. A total of 2798 samples were collected including goats (1979) and sheep (819) from villages in 27 randomly selected districts. These were tested by cELISA for PPRV and true prevalence estimates were calculated by Rogan and Gladen estimator. Overall, 1273 (45.5%) were found positive; 980 (49.5%) of 1979 samples from goats and 293 (35.8%) of 819 serum samples from sheep were positive. The true sero-prevalence of PPR was estimated to be 48.5% (95% CI, 46.6-50.3), and 52.9% (95% CI, 50.7-55.1) and 37.7 (95% CI, 34.4-41.0) for goats and sheep, respectively. PPR virus is widely distributed all across Pakistan and has become an endemic infection of small ruminants. Since it is one of the leading causes of morbidity and mortality in small ruminants, it poses a serious threat to food security and the rural economy in Pakistan.

Characterization of a novel lipase from Bacillus sp. isolated from tannery wastes

Kinetics of a lipase isolated from Bacillus sp. was studied. The enzyme showed maximum activity at pH 9 and temperature 60°C. The Michaelis constant (KM 0.31 mM) obtained from three different plots i.e., Lineweaver-Burk, Hanes-Wolf and Hofstee, was found to be lower than already reported lipases that confirmed higher affinity of the enzyme for its substrate p-NPL (p-nitrophenyl laurate). Vmax of the enzyme was found to be 7.6 µM/mL/min. Energy of activation calculated from Arrhenius plot was found to be 20.607 kJmol(-1). Activation enthalpy (ΔH*) had negative trend and the value for the hydrolysis of p-NPL by the enzyme at optimum temperature was -2.748 kJmol(-1). Activation entropy (ΔS*) and free energy of activation (ΔG*) of the enzyme were found to be 1.468 Jmol(-1)K(-1) and -3.237 kJmol(-1), respectively at optimum temperature. Low value of Q10 (0.04788) shows high catalytic activity of the enzyme. Mn(2+), Fe(2+) and Mg(2+) enhanced the lipase activity whereas Cu(2+), Na(+) and Co(2+) inhibited the enzyme activity. However, the enzyme activity was not affected significantly by K(+) ions. EDTA and SDS also significantly inhibited the lipase activity. Activity of the enzyme was increased in n-hexane while decreased with increase in concentration of acetone, chloroform, ethanol and isopropanol.

Use of a pedicled flap for reconstruction of extensive soft tissue defects around elbow

OBJECTIVE

To determine the reliability of pedicled latissimus dorsi flap for reconstruction of extensive defects around the elbow in terms of flap survival and coverage of exposed bones, vessels or nerves.

STUDY DESIGN

Case series.

PLACE AND DURATION OF STUDY

Department of Plastic and Reconstructive Surgery at Shaikh Zayed Hospital, from February 2003 to January 2008.

METHODOLOGY

Patients with extensive traumatic wounds around the elbow and wounds secondary to release of postburn elbow contracture were included. Patients above 60 years of age with previous history of myocardial infarct, heart failure, chronic obstructive pulmonary disease or insulin dependent diabetes were excluded. Pedicled latissimus dorsi flap was used for defect reconstruction. Overall flap survival and postoperative complications were the outcome measures.

RESULTS

There were 28 patients, including 20 males and 8 females, age ranging from 17 to 60 years. Evaluation of the defect considering extent of tissue loss, depth of the defect and exposed vital structure was done. Myocutaneous flap was used in 4 (14%) patients. Muscle only flap was used in 24 patients (86%). Twenty five (90%) flaps survived completely and 3 (10%) had partial loss. Other minor complications were partial graft loss seen in 3 (10%) patients and wound infection seen in 2 (7%) patient. There was no considerable morbidity at donor site and all patients had satisfactory healing.

CONCLUSION

Pedicled latissimus dorsi flap is a reliable and safe option for resurfacing extensive soft tissue defects of arm, elbow and forearm.