Integration of measurable residual disease by WT1 gene expression and flow cytometry identifies pediatric patients with high risk of relapse in acute myeloid leukemia

Background

Molecular testing plays a pivotal role in monitoring measurable residual disease (MRD) in acute myeloid leukemia (AML), aiding in the refinement of risk stratification and treatment guidance. Wilms tumor gene 1 (WT1) is frequently upregulated in pediatric AML and serves as a potential molecular marker for MRD. This study aimed to evaluate WT1 predictive value as an MRD marker and its impact on disease prognosis.

Methods

Quantification of WT1 expression levels was analyzed using the standardized European Leukemia Network real-time quantitative polymerase chain reaction assay (qRT-PCR) among a cohort of 146 pediatric AML patients. Post-induction I and intensification I, MRD response by WT1 was assessed. Patients achieving a ≥2 log reduction in WT1MRD were categorized as good responders, while those failing to reach this threshold were classified as poor responders.

Results

At diagnosis, WT1 overexpression was observed in 112 out of 146 (76.7%) patients. Significantly high levels were found in patients with M4- FAB subtype (p=0.018) and core binding fusion transcript (CBF) (RUNX1::RUNX1T1, p=0.018, CBFB::MYH11, p=0.016). Following induction treatment, good responders exhibited a reduced risk of relapse (2-year cumulative incidence of relapse [CIR] 7.9% vs 33.2%, p=0.008). Conversely, poor responders' post-intensification I showed significantly lower overall survival (OS) (51% vs 93.2%, p<0.001), event-free survival (EFS) (33.3% vs 82.6%, p<0.001), and higher CIR (66.6% vs 10.6%, p<0.001) at 24 months compared to good responders. Even after adjusting for potential confounders, it remained an independent adverse prognostic factor for OS (p=0.04) and EFS (p=0.008). High concordance rates between WT1-based MRD response and molecular MRD were observed in CBF patients. Furthermore, failure to achieve either a 3-log reduction by RT-PCR or a 2-log reduction by WT1 indicated a high risk of relapse. Combining MFC-based and WT1-based MRD results among the intermediate-risk group identified patients with unfavorable prognosis (positive predictive value [PPV] 100%, negative predictive value [NPV] 85%, and accuracy 87.5%).

Conclusion

WT1MRD response post-intensification I serves as an independent prognostic factor for survival in pediatric AML. Integration of WT1 and MFC-based MRD results enhances the reliability of MRD-based prognostic stratification, particularly in patients lacking specific leukemic markers, thereby influencing treatment strategies.

Patterns and Outcomes of Acute Central Nervous System Complications During Treatment of Childhood Acute Lymphoblastic Leukemia: A Single-center Experience

Central nervous system (CNS) complications are considered adverse events during the treatment of pediatric acute lymphoblastic leukemia (ALL). This study aimed to assess the incidence, types, clinical and radiologic patterns, risk factors, and the fate of different CNS complications during the treatment of pediatric ALL. A retrospective study included 390 patients with pediatric ALL, treated according to St. Jude total XV protocol at the National Cancer Institute, Cairo University, from January 2012 to December 2017. Thirty-nine (10%) patients developed different types of CNS complications. Nineteen (4.9%) patients had cerebrovascular complications, 12 (3.1%) patients had posterior reversible encephalopathy syndrome (PRES), and 6 (1.5%) patients had leukoencephalopathy; both CNS infections and leukemic infiltrates were diagnosed in one patient each. CNS complications were significantly higher in patients older than 10 years old, patients with high-risk disease, and patients who were classified as CNS III status with a statistically significant P value of 0.040, 0.020, and 0.002, respectively. There were 31 (79.5%) cases that achieved complete recovery, 6 (15.4%) patients who died, and 2 (5.1%) patients who developed residual neurological deficits. In conclusion, pediatric patients with ALL, who presented with older age, high-risk disease initially, and had initial CNS III status, were at higher risk of developing acute CNS complications during their treatment period. Patients who developed visual disturbances were associated with unfavorable outcomes. Despite that, around 80% of patients showed complete recovery, but still, 15% of them died from these complications.

Optimizing cyclosporine A dose post allogeneic hematopoietic stem cell transplantation in paediatric cancer patients

BACKGROUND/OBJECTIVES

Cyclosporine A (CSA) dosing has been complicated by considerable intra-patient and inter-patient variability in pharmacokinetics, which is affected by different factors. We aimed to assess the various factors that might affect the CSA dose and its plasma level.

PATIENTS AND METHODS

This retrospective study included paediatric cancer patients who underwent allogeneic hematopoietic stem cell transplant at the Children's Cancer Hospital Egypt 57357 from matched related donors with CSA as graft versus host disease prophylaxis. The CSA initial dose was 1.5 mg/kg IV Q12H. Then, it was titrated according to the level and drug toxicity. Cyclosporine A trough levels were assessed two to three times per week using the Emit 2000 cyclosporine-specific assay. Moreover, factors that may affect cyclosporine levels, such as age, sex, weight and the antifungal used, were analyzed to determine their effect on CSA plasma levels.

RESULTS

There were 119 patients included in the study. The median age was 10 years; and 43% of them used voriconazole as a prophylactic antifungal. The multivariate analysis revealed that female patients, those >9 years or on voriconazole reached the target level at low initial CSA doses. A higher probability (93%) of reaching the desired plasma level with doses 1.5 mg/kg IV Q12H was observed among patients >9 years, and on voriconazole. While those who were ≤9 years and not on voriconazole required doses >1.5 mg/kg IV Q12H, with an 89% probability of reaching the desired level.

CONCLUSION

This study suggests that the initial CSA dose should consider the patient's age and the antifungal used. Patients >9 years and/or on voriconazole may require lower initial CSA doses and could start with 1.5 mg/kg IV Q12H.

Carbapenem-Resistant Enterobacteriaceae (CRE) among Children with Cancer: Predictors of Mortality and Treatment Outcome

Carbapenem-resistant Enterobacteriaceae (CRE) is an important emerging threat among pediatric cancer patients, with a high mortality rate. This retrospective study included all pediatric cancer patients with (CRE) bloodstream infections (BSIs) at a children's cancer hospital in Egypt (2013-2017). Two hundred and fifty-four pediatric cancer patients with CRE BSI were identified; 74% had hematological malignancies, and 26% had solid tumors. Acute myeloid leukemia was the most common hematological malignancy (50%). The main clinical features for acquiring CRE-BSI were previous antibiotics exposure (90%), profound neutropenia (84%), prolonged steroid use (45%), previous colonization with a resistant pathogen (35%), ICU admission within 90 days (28%), and central venous catheter use (24%). E. coli was the most common isolated pathogen (56%), followed by Klebsiella pneumoniae (37%). All isolates were resistant to carbapenem with an MIC < 4-8 μg/mL in 100 (45%) and >8 μg/mL in 153 (55%). The overall mortality rate was 57%, and 30 day mortality was reported in 30%. Upon multivariate analysis, for the patients with Klebsiella pneumoniae BSI, carbapenem resistance with an MIC > 8 μg/mL and associated typhlitis or pneumonia were predictors of poor outcome. In conclusion, CRE-BSI is a major threat among pediatric cancer patients in limited resource countries with limited options for treatment. Antimicrobial stewardship for early detection through routine screening, adequate empirical treatment, and timely adequate therapy may impact the outcome for such high-risk patient groups.

Viable production of hydrogen and methane from polluted water using eco-friendly plasmonic Pd-TiO2 nanocomposites

Solar-to-fuel conversion is a novel clean energy approach that has gained the interest of many researchers. Solar-driven photocatalysts have become essential to providing valuable fuel gases such as methane and hydrogen. Solar energy has emerged as a renewable, abundant energy source that can efficiently drive photochemical reactions through plasmonic photocatalysis. As a capping agent, orange peel extract was used in this study in a microwave-assisted green method to incorporate titanium dioxide with distinct amounts (3, 5, and 7 wt%) from Pd-plasmonic nanoparticles (2-5 nm). The leading role for plasmonic nanoparticles made from Pd-metal is enhancing the photocatalyst's ability to capture visible light, improving its performance. X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Brunauer, Emmett, and Teller (BET) surface area analysis, and UV-vis DRS analyses have investigated the obtained plasmonic photocatalysts' crystallographic, morphological, and optical characteristics. The UV-vis absorption spectra demonstrated the visible light absorption capacity attributed to the localized surface plasmonic resonance (LSPR) behavior of the newly formed nanoplasmonic photocatalysts. The generated Pd-TiO2 nanomaterials' photocatalytic activity has been examined and evaluated for combustible gas production, including the formation of CH4 and H2 from the photocatalytic degradation of Reactive Yellow 15 (RY) during a deoxygenated photoreaction in a homemade solar photobiogas reactor.

Cost-effectiveness of childhood cancer treatment in Egypt: Lessons to promote high-value care in a resource-limited setting based on real-world evidence

BACKGROUND

Childhood cancer in low-and middle-income countries is a global health priority, however, the perception that treatment is unaffordable has potentially led to scarce investment in resources, contributing to inferior survival. In this study, we analysed real-world data about the cost-effectiveness of treating 8886 children with cancer at a large resource-limited paediatric oncology setting in Egypt, between 2013 and 2017, stratified by cancer type, stage/risk, and disease status.

METHODS

Childhood cancer costs (USD 2019) were calculated from a health-system perspective, and 5-year overall survival was used to represent clinical effectiveness. We estimated cost-effectiveness as the cost per disability-adjusted life-year (cost/DALY) averted, adjusted for utility decrement for late-effect morbidity and mortality.

FINDINGS

For all cancers combined, cost/DALY averted was $1384 (0.5 × GDP/capita), which is very cost-effective according to WHO-CHOICE thresholds. Ratio of cost/DALY averted to GDP/capita varied by cancer type/sub-type and disease severity (range: 0.1-1.6), where it was lowest for Hodgkin lymphoma, and retinoblastoma, and highest for high-risk acute leukaemia, and high-risk neuroblastoma. Treatment was cost-effective (ratio <3 × GDP/capita) for all cancer types/subtypes and risk/stage groups, except for relapsed/refractory acute leukaemia, and relapsed/progressive patients with brain tumours, hepatoblastoma, Ewing sarcoma, and neuroblastoma. Treatment cost-effectiveness was affected by the high costs and inferior survival of advanced-stage/high-risk and relapsed/progressive cancers.

INTERPRETATION

Childhood cancer treatment is cost-effective in a resource-limited setting in Egypt, except for some relapsed/progressive cancer groups. We present evidence-based recommendations and lessons to promote high-value in care delivery, with implications on practice and policy.

FUNDING

Egypt Cancer Network; NIHR School for Primary Care Research; ALSAC.

Outcome and safety of colistin usage in pediatric cancer patients with carbapenem-resistant enterobacteriaceae bacteremia at children cancer hospital Egypt

Background

Carbapenem resistant Enterobacteriacae (CRE) bloodstream infection (BSI) causes complicated infections, especially in immunocompromised patients. This study aimed to assess the renal toxicity and the efficacy of therapy with colistin in a cohort of pediatric cancer patients with BSIs due to CRE and sensitivity to colistin.

Patients and Methods

This was an observational, prospective cohort study from May 2017 to October 2017 in Children's Cancer Hospital Egypt 57,357. All patients who had blood stream infections due to CRE receiving intravenous colistin were prospectively enrolled. We used a standardized case form to record patient characteristics, including age, sex, weight, underlying comorbidities, type of infection, causative organism, and antibiotic susceptibility testing. Daily doses, duration of colistin therapy, and co-administered antibiotics (aminoglycosides, vancomycin) were collected. Furthermore, clinical and microbiological responses to treatment were reported. The dosing schedule was based on a loading dose of 5 MU and a 5-MU twice-daily divided maintenance dose, titrated on renal function. Clinical cure, bacteriological clearance, and daily serum creatinine were recorded.

Results

One hundred and forty-one Blood Stream infectious episodes mainly due to Klebsiella Species (pneumoniae and Oxytoca) (27%) and Escherichia coli (68%) were analyzed. All strains were susceptible to colistin with Minimum inhibitory concentration (MICs) of 0.19-1.5 mg/L. Patients were predominantly females (69%), with a mean age of 7 years. It was used as a combination therapy with carbapenems (69.2%) or aminoglycosides (80%). The median duration of treatment was 9 days (Range 1-50 days). Clinical and microbiological cure was observed in 110 cases (80%). Acute kidney injury developed during five treatment courses (4%) in which colistin was used in combination with amikacin. No renal replacement therapy was required and subsided within 7 days from colistin discontinuation.

Conclusions

Our study showed that colistin had a high efficacy without significant renal toxicity in severe infections due to CRE Gram-negative bacteria.

Stimulated generation of photobiogas by morphologically tuned nanostructured ZnO and ZnO/TiO2

The photocatalytic degradation (PCD) of ethanol in an inert atmosphere on catalysis was explored in a lab-scale experiment. A morphologically tuned nanostructured controlled ZnO and ZnO/TiO₂ nanocomposites were synthesized using a simple hydrothermal process under the control of several functionally capping agents marking a milestone in photocatalysis. It is possible that this could be modified to produce photobiogas out of organic dye pollution. The photocatalysts were characterized by the use of X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer, Emmett, and Teller (BET) surface area analyzer, Scanning electron microscope (SEM-EDX), and UV–Vis absorption spectroscopy. The photocatalytic activity of the ZnO and ZnO–TiO₂ composite nanostructures was evaluated for the photodegradation of the Tartrazine (Tr) dye aqueous solution. Where the composite matrix exhibits higher photocatalytic activity than pure ZnO nanomaterials as a result of the synergistic interaction between ZnO and TiO₂ particles. This is mainly due to its higher surface area than pure ZnO. Moreover, the photocatalytic activity of the tuned nanostructured materials is found to be enhanced by the effect of the capping agent and controlling the morphology. This increase is accompanied by a significant shift in surface shape and band gap energy. According to the findings, the designed morphologies of pure ZnO photocatalyst impacted the formation of photobiogas from the photocatalytic decomposition of ethanol as a model of organic pollutants in wastewater. However, when using composite ZnO/TiO₂ photocatalysts, the rate of CH₄ formation is significantly lower than when using ZnO photocatalysts alone. This may be attributed to the synergetic effect between ZnO and TiO₂ particles which leads to a remarkable reduction in the newly formed band gap energy. This may result in a fast rate of recombination between the photogenerated charge carriers (e⁻ and h⁺).

Hematopoietic stem cell transplantation from HLA-matched sibling donors in children with acute lymphoblastic leukemia: A report from the Children’s Cancer Hospital Egypt

Introduction

Allogeneic hematopoietic stem cell transplantation (HSCT) is widely used for high-risk acute lymphoblastic leukemia (ALL) patients in their first complete remission (CR1), and for relapsed patients in second complete remission (CR2).

Patients and methods

We retrospectively analyzed data for 67 children with ALL, from a cancer center in a low/middle income country, who had undergone HSCT from human leukocyte antigen (HLA)-matched sibling donors (MSDs) using myeloablative conditioning (MAC) regimens, between 2007 and 2020, describing the survival outcome and relapse probability after achieving CR1 and CR2 and determining outcome differences in relation to indications for HSCT in patients transplanted in CR1. All patients had achieved a negative minimal residual disease prior to transplant (&lt;0.01%).

Results

Forty-six patients (68.7%) were in CR1; 25 had adverse cytogenetics, including 18 patients with Philadelphia chromosome-positive ALL (Ph-positive ALL), and 21 had poor induction response. The 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) for the whole cohort were 56.1% (95% CI, 42.8%-69.4%), 49% (95% CI, 35.7%-62.3%) and 33.5% (95% CI, 21.7%-45.8%), respectively with better EFS and CIR for CR1 transplants compared to CR2 transplants (P=0.02 and P=0.03, respectively). Patients with Ph-positive ALL had better 5-year OS, EFS and non-relapse mortality (NRM) compared with other CR1 transplants (P=0.015, P=0.009 and P=0.028, respectively).

Conclusion

Hematopoietic stem cell transplantation from MSD for ALL in CR1 group had superior outcomes compared to CR2 group and was apparently a curable option for Ph-positive ALL without an increased risk of non-relapse mortality. Poorer survival rates and higher relapse probabilities were associated with HSCT conducted to patients who had a poor response to induction therapy or suffered a relapse.

Integrated two-phase acidogenic-methanogenic treatment of municipal sludge with thermal hydrolysis

The purpose of this research was to investigate the impact of two process configurations integrating two-phase anaerobic digestion (AD) of municipal sludge with thermal hydrolysis (TH). The TH was positioned either before or after the acidogenic fermentation phase. The fermentation process was carried out under the semi-continuous flow regime with a retention time of three days. The TH was done at a temperature of 170 °C and for 30 min. Among all the tested scenarios, the TH of sludge followed by the acidogenic fermentation resulted in the highest COD solubilization ratio (39.5%) and volatile fatty acids production (6,420 ± 400 mg/L), which was 630% and 500% more than that of the raw sludge, respectively. The sequential TH/fermentation process achieved 40% higher ultimate methane yield (240 mL/g COD) than the non-pretreated (raw) sludge. Positioning TH after the fermentation process reduced the ultimate methane yield to 231 240 mL/g COD, although it was still 32% higher than that of the raw sludge. The analysis of methane production rate and biodegradation kinetics data suggested the formation of refractory intermediates during the thermal process of sludge, which reduced the overall performance rate during the first week of the AD process. It was also revealed that acidogenic fermentation of thermally-processed sludge could diminish the adverse effect of the recalcitrant compounds formed during the thermal hydrolysis on the subsequent AD process.

MECOM gene overexpression in pediatric patients with acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is characterized by blocked or aberrant differentiation of hematopoietic stem cells. The MECOM gene overexpression in hematopoietic progenitors induces myeloid differentiation block, resulting in increased self-renewal and survival of these transformed progenitors. However, its exact role in AML remains unclear. We aimed to estimate the prevalence of MECOM overexpression among pediatric AML patients, and assess its impact on clinical outcome.

PATIENTS AND METHODS

Real-time quantitative polymerase chain reaction and Livak method (2^ΔΔCt) were used to determine relative MECOM expression level among 243 pediatric patients with AML. MECOM overexpression was considered if the cumulative relative expression was above 1 (2^-ΔΔCt) and was designated as MECOM^pos.

RESULTS

Of 243 AML patients tested 57(23.5%) demonstrated MECOM^pos. Patients with MECOM^pos had significantly lower median age. The frequency of MECOM^pos was significantly higher among AML patients with 11q23 abnormalities, complex karyotypes and among high- and intermediate-risk groups compared to low-risk group (p = .014). MECOM^pos patients had significantly lower overall survival (OS) (38.7 vs. 78.9%, p < .001), event-free survival (EFS) (37.3% vs. 68.4%, p < .001), and had higher cumulative incidence of relapse (49.5% vs. 23.5%, p = .002) at 36 months compared to MECOM^neg patients. Multivariate analysis revealed that MECOM^pos was an adverse prognostic factor for OS (hazards ratio (HR) = 2.11, 95% confidence interval (CI) 1.24-3.60, p = .006) and EFS (HR= 1.71, 95% CI 1.07-2.75, p = .025). The logistic regression model showed that MECOM^pos was an independent prognostic factor regardless of minimal residual disease status post first induction therapy in the intermediate-risk group (odds ratio 2.89; 95% CI 1.19-6.57, p = .018).

CONCLUSION

The aberrant MECOM gene expression is an adverse prognostic factor, especially in patients without previously known cytogenetic risk factors. Our results suggest the potential benefit from pretreatment screening for MECOM gene overexpression in newly diagnosed AML patients for better risk stratification and treatment adjustment.

Novel fluorescent nano-sensor based on amino-functionalization of Eu3+:SrSnO3 for copper ion detection in food and real drink water samples

Lanthanide-doped nanoparticles exhibit unique optical properties and have been widely utilized for different sensing applications. Herein, the Eu3+:SrSnO3@APTS nanosensor was synthesized and its optical properties were analyzed using UV-Vis and photoluminescence spectroscopy. The TEM images of the synthesized nanophosphor Eu3+:SrSnO3@APTS exhibited peanut-like morphology, composed of two or more spherical nanoparticles with an average diameter ∼33 nm. Effects of environmental pH values and doping concentrations as well as amino functionalization on the structure of Eu3+:SrSnO3 were investigated. The as-synthesized optical nanosensor was used for determination of copper ions based on a fluorescence quenching approach. Red emission with a long lifetime was obtained in the case of the 0.06 mol Eu3+:SrSnO3@APTS sample. Under the optimal experimental conditions, a Stern-Volmer plot exhibited a good linearity for copper ions over the concentration (0.00-10.8) × 10-11 mol L-1 with a correlation efficient of 0.996 and a limit of detection 3.4 × 10-12 mol L-1. The fluorescent sensor was dynamically quenched via a coulombic interaction mechanism between the Eu3+ (5L6) and Cu2+. The Eu3+:SrSnO3@APTS nanosensor with the optimal Eu3+ dopant concentration of 0.06 mol was applied for copper determination in food and real drink water samples with high recovery values. We believe that the developed nanosensor probe can also be used for the detection of other toxic compounds, with high selectivity and sensitivity.

Temporal trends in childhood cancer survival in Egypt, 2007 to 2017: A large retrospective study of 14 808 children with cancer from the Children's Cancer Hospital Egypt

Childhood cancer is a priority in Egypt due to large numbers of children with cancer, suboptimal care and insufficient resources. It is difficult to evaluate progress in survival because of paucity of data in National Cancer Registry. In this study, we studied survival rates and trends in survival of the largest available cohort of children with cancer (n = 15 779, aged 0-18 years) from Egypt between 2007 and 2017, treated at Children's Cancer Hospital Egypt-(CCHE), representing 40% to 50% of all childhood cancers across Egypt. We estimated 5-year overall survival (OS) for 14 808 eligible patients using Kaplan-Meier method, and determined survival trends using Cox regression by single year of diagnosis and by diagnosis periods. We compared age-standardized rates to international benchmarks in England and the United States, identified cancers with inferior survival and provided recommendations for improvement. Five-year OS was 72.1% (95% CI 71.3-72.9) for all cancers combined, and survival trends increased significantly by single year of diagnosis (P < .001) and by calendar periods from 69.6% to 74.2% (P < .0001) between 2007-2012 and 2013-2017. Survival trends improved significantly for leukemias, lymphomas, CNS tumors, neuroblastoma, hepatoblastoma and Ewing Sarcoma. Survival was significantly lower by 9% and 11.2% (P < .001) than England and the United States, respectively. Significantly inferior survival was observed for the majority of cancers. Although survival trends are improving for childhood cancers in Egypt/CCHE, survival is still inferior in high-income countries. We provide evidence-based recommendations to improve survival in Egypt by reflecting on current obstacles in care, with further implications on practice and policy.

Changes in glomerular filtration rate and clinical course after sequential doses of carboplatin in children with embryonal brain tumors undergoing autologous stem cell transplantation

BACKGROUND

Treatment for malignant embryonal brain tumors in young children usually employs cycles of standardly dosed cisplatinum followed by high-dose carboplatinum-containing conditioning with single or tandem autologous stem cell rescue (HDC-ASCR). High-dose carboplatin is potentially nephrotoxic, and additive platinum exposure may acutely impact renal function. Aiming to determine if decrease in renal function during conditioning assessed prior to each carboplatin dose was associated with acute increases in creatinine, requirement for dialysis or transplant-related mortality (TRM). This was a retrospective study of consecutive patients with medulloblastoma (n = 15) / atypical teratoid/rhabdoid tumor (AT/RT, n = 5) receiving HDC-ASCR. Fifteen patients underwent 1 HDC-ASCR (carboplatin × 3 doses/ etoposide/ thiotepa) and 5 patients underwent at least 1 of 3 planned tandem HDC-ASCR (carboplatin × 2 doses/ thiotepa). Renal function was assessed by daily creatinine and nuclear medicine glomerular filtration rate (GFR)/ creatinine clearance before each carboplatin dose.

RESULTS

In this cohort of 20 patients, 3 had doses of carboplatin omitted due to decreases in GFR: 1 did not develop nephrotoxicity, 1 experienced nephrotoxicity without need for dialysis, and 1 required dialysis temporarily but recovered renal function. Two patients did not have GFR changes but developed post-ASCR renal failure requiring dialysis and TRM.

CONCLUSION

Daily assessment of renal function by GFR, prior each dose of carboplatin during HDC-ASCR, will help in protecting the kidney in heavily treated population of oncology/HSCT patients. Although the study had a small number of patients which is a major limitation of the study, but it points to a serious transplant-related morbidity and mortality. So, larger scale studies are needed to clarify the best approach to carboplatin dosing to insure the optimal balance between efficacy and toxicity.

RAS Pathway Mutation Patterns in Patients With Juvenile Myelomonocytic Leukemia: A Developing Country Single-center Experience

INTRODUCTION

Juvenile myelomonocytic leukemia (JMML) is a rare clonal myelodysplastic/myeloproliferative neoplasm of early childhood. Historically, it was difficult to diagnose clinically, as patients present with manifestations shared with other hematologic malignancies or viral infections. It is now clear that JMML is a disease of hyperactive RAS signaling.

PATIENTS AND METHODS

We examined the bone marrow of 41 Egyptian children with JMML by direct sequencing for mutations in the RAS pathway genes.

RESULTS

Mutations were detected in 33 (80%) of 41 patients. We identified 12 (29%) of 41 patients with PTPN11 mutation; 18 (44%) of 41 with RAS mutation; 9 (22%) of 41 with NRAS mutation; 9 (22%) of 41 with KRAS mutation; and 3 (7%) of 41 with CBL mutation. Eleven (92%) of the PTPN11 mutations were detected in exon 3 and 1 (8%) in exon 13. Seven of the NRAS mutations were in exon 2, and 2 were in exon 3. All KRAS mutations were in exon 2. The 3 cases with CBL mutation were homozygous mutations in exon 8. All the mutations detected in PTPN11, NRAS/KRAS, and the CBL genes were previously reported missense mutations in JMML.

CONCLUSION

Our results demonstrate that Egyptian children diagnosed with JMML have high frequency of NRAS/KRAS mutations and lower frequency of PTPN11 mutations as compared with previous studies. The concept of mutually exclusive RAS pathway mutations was clearly observed in our patients. All cancer centers in our region should start implementing molecular diagnostic methods before confirming the diagnosis of JMML and before offering hematopoietic stem cell transplantation.

Incidence, risk factors, and outcome of blood stream infections during the first 100 days post-pediatric allogeneic and autologous hematopoietic stem cell transplantations

Bloodstream infections (BSI) are a frequently observed complication after hematopoietic stem cell transplant (HSCT). Retrospective analysis of clinical and microbiological data during the first 100 days from 302 consecutive pediatric patients who underwent HSCT for a malignant disease at our institute between January 2013 and June 2017. A total of 164 patients underwent autologous and 138 allogeneic HSCT. The overall incidence of BSI was 37% with 92% of infectious episodes occurring during the pre-engraftment phase. Gram-positive bacteria (GPB) accounted for 54.6% of the isolated pathogens, gram-negative bacteria (GNB) for 43.9%, and fungi for 1.4%. Coagulase-negative staphylococci and Escherichia coli were the most commonly isolated GPB and GNB, respectively. Forty-five percent of GNB were extended-spectrum beta-lactamase producers and 21% were multidrug-resistant organisms. Fluoroquinolone resistance was 92% and 68%, among GPB and GNB, respectively. Risk factors for BSI in univariate analysis were allogeneic HSCT, delayed time to engraftment more than 12 days, previous BSI before HSCT, and alternative donor. In multivariate analysis, only HSCT type (allogeneic vs autologous P = .03) and previous BSI within 6 months before HSCT (P = .016) were significant. Overall survival at day 100 was 98% and did not differ significantly between patients with and without BSI (P = .76). BSI is common in children undergoing HSCT for malignant diseases. Allogeneic HSCT recipients and previous BSI within 6 months before HSCT are associated with increased risk of post-transplant BSI. With current supportive measures, BSI does not seem to confer an increased risk for 100-day mortality.

Photovoltaic and spectroscopic characteristics of perovskite/TiO2 heterostructure photoanodes for improving the efficiency of dye sensitized solar cells

Perovskite-type ternary oxide nanostructured materials have gained great attention in recent years as promising materials for solar cell applications. However these ternary oxides have failed to be applied as a working electrode in DSSCs due to its poor performance and its inability to bind dye molecules to the surface. A heterostructure perovskite/TiO₂ photoactive electrodes is a new strategy to improve the photon-to-current efficiency (PCE) of DSSCs. In this paper, BaZrO₃ (BZ), BaTiO₃ (BT) and nanocomposite [1:1] molar% from BaTiO₃-BaZrO₃ perovskite nanostructured materials synthesized via sonochemical sol-gel methods, are coated on the top of the TiO₂ photoactive electrode. This heterostructured (perovskite/TiO₂) photoelectrode has been applied for improving the performance of dye-sensitized solar cells (DSSCs). The crystallographic, morphological and optical characteristics of the different prepared perovskite nanomaterials has been investigated by XRD, SEM, TEM, Raman and UV-Vis Diffuse reflectance spectroscopic analysis, respectively. Dye-sensitized solar cells based on the different heterostructure perovskite/TiO₂ electrodes are assembled, and high conversion efficiency (η) are calculated from the current density-voltage (J-V) characteristics of the solar cells. The results show an efficiency enhancement with about ∼22%, 37% and 51% in case of BZ, BTZ and BT respectively. These enhancements is attributed to high refractive index of the perovskite nanoparticles, higher incident photon-to-current conversion yield which is due to greater fraction of light scattered, as well as the less recombination of the photogenerated electrons.

Clinical features and outcome of hepatosplenic fungal infections in children with haematological malignancies

Hepatosplenic fungal infection (HSFI) is a severe invasive fungal infection observed during neutrophil recovery in patients with acute leukaemia treated with intensive chemotherapy. Retrospective analysis including all paediatric haematological malignancies patients with HSC treated in Children Cancer Hospital Egypt (2013-2018). Twenty-five patients with acute leukaemia developed HSFI (19 patients diagnosed as hepatosplenic candidiasis). Most of the cases (92%) occurred during the induction phase. Organs affected were as follows: liver in 18 patients, renal in 13 patients, spleen in 12 patients, skin in four patients and retina in one patient. Five (20%) patients had proven HSC, 14 (56%) probable and six (24%) possible HSFI. Ten patients had a PET-CT for response assessment. Candida tropicalis was the most common isolated spp. from blood/tissue culture. Six (24%) patients developed HSFI on top of antifungal prophylaxis. Steroids were given in 12 (52%) patients with HSFI as immune reconstitution syndrome (IRS). Caspofungin was the first line of treatment in 14 (56%) patients, liposomal amphotericin B in six (24%) patients and azoles in five (20%) patients. HSFI was associated with delayed of intensification phase of chemotherapy (median 42 days). The success rate was reported in 24 patients with complete response (68%) and partial response in (28%) patients, while failure (death) seen in 1(4%) patient. HSC is still a major challenge in paediatric leukaemias patients with impact on treatment delay and survival outcome. PET scan, non-culture diagnostics and steroid role evidence in IRS are growing. Antifungal stewardship for screening, early detection for high-risk patients and better response assessment is challenging.

Outcome predictors of autologous hematopoietic stem cell transplantation in children with relapsed and refractory Hodgkin lymphoma: Single-center experience in a lower-middle-income country

BACKGROUND

Children and adolescents with HL have excellent long-term survival exceeding 95% after combined modality treatment. However, about 20% will either relapse or have PRF. Salvage HDCT followed by AHSCT is considered to be the preferential treatment.

OBJECTIVE

To describe the outcome (OS and EFS) and prognostic factors in pediatric patients with relapsed or refractory HL (r/rHL) who underwent AHSCT.

METHODS

We retrospectively included 43 pediatric patients with r/rHL who underwent AHSCT from July 1, 2007, till December 31, 2016, at the Children's Cancer Hospital of Egypt. MAC regimen given was CMV.

RESULTS

Of the whole cohort, 88.4% of patients achieved CR, while 11.6% had a positive PET scan prior to transplantation. The 3-year OS and EFS were 85% and 70.6%, respectively. The 3-year OS for patients > 10 years was 94% versus 65.5% for patients 10 years of age or younger (P = 0.046). There is strong tendency toward better 3-year OS for patients with negative PET scan as compared to those with positive PET scan before AHSCT, 89.4% vs 60%, respectively (P = 0.059). This tendency is also applicable when looking at the 3-year EFS for the two groups, 78.3% vs 40%, respectively (P = 0.069).

CONCLUSION

Poor predictors of OS were younger age and positive PET scan before AHSCT. The latter, along with single modality treatment before AHSCT, were poor predictors of EFS.

Overview and outcome of mucormycosis among children with cancer: Report from the Children's Cancer Hospital Egypt

Mucormycosis represents a real challenge in immunocompromised patients. This study aimed to describe the clinical characteristics, treatment outcome and infection-related mortality in our patients at the Children's Cancer Hospital 57357, Cairo, Egypt. This is a retrospective study during the period 2007-2017. Data analysis included demographic data, risk factors, diagnostic workup, treatment and outcome. During the study period, 45 patients developed proven mucormycosis according to EORTC/MSG criteria (2008). Ninety percentof cases were of haematological malignancies. Liposomal amphotericin B was the mainstay of treatment. Posaconazole was used as secondary prophylaxis in 35% of cases. Combination antifungal was used in three cases with progressive mucormycosis. Surgical intervention was achievable in 50% of cases. Therapy was successful in 35 patients (66%). Complications related to mucormycosis were seen in five cases with disfigurement and perforated hard palate. Chemotherapy delay with subsequent relapse of primary malignancy was reported in one case. Mucormycosis-related mortality was 33% (15 cases). Mucormycosis is a major cause of mortality among patients with haematological malignancies. Early diagnosis of Mucormycosis infection, with rapid initiation of appropriate antifungal therapy and surgical intervention, whenever feasible, is the backbone of mucormycosis treatment.

A comprehensive dataset on anaerobic digestion of cattle manure, source separated organics, and municipal sludge using different inoculum sources

The dataset reported in this article provides quantitative data on anaerobic digestion of cattle manure, source separated organics (SSO), primary sludge (PS), and thickened waste activated sludge (TWAS) using different inoculum sources. The discussion and interpretation of the data are provided in another publication entitled “Comparison of liquid and dewatered digestate as inoculum for anaerobic digestion of organic solid wastes” [1]. The data presented in this article include 1) the gas chromatography (GC) procedure of determining the biogas composition, 2) the procedure of converting the daily biogas/methane production data from the experimental condition (mesophilic temperature of 38 °C and room pressure) to the standard temperature (0 °C) and pressure (1 atm) condition, 3) the specific methanogenic activity data, and 4) the methane daily production rate data, and 5) the organics biodegradation kinetic rates.

Comparison of liquid and dewatered digestate as inoculum for anaerobic digestion of organic solid wastes

In this study, the application of liquid and dewatered digestate was compared for the inoculation of the anaerobic digestion (AD) process. In addition to the specific methanogenic activity and biohydrogen potential tests, biochemical methane potential assay was also conducted using four different types of municipal and industrial waste streams (primary sludge, thickened waste activated sludge, source separated organics, and cattle manure). The specific methanogenic activity of the digestate cake (5.0 ± 0.5 mL-CH₄/g-VSS.d) was higher than that of the liquid digestate (3.4 ± 0.2 mL-CH₄/g-VSS.d) for the food to microorganism ratio of 0.5. The BMP results also revealed that regardless of the type of the substrate used, the application of the digestate cake as inoculum achieved statistically significantly higher methane production rate compared to the utilization of liquid digestate, most likely due to the lower concentration of dissolved contents (i.e., ammonia, soluble organic matter, heavy metals, etc.) in the diluted digestate cake. Despite the increased process rate, no statistically significant effect of the type of the inoculum was observed on the ultimate methane yield. The biohydrogen potential test revealed the similar performance of the digestate- and digestate cake-inoculated digesters in terms of biohydrogen and volatile fatty acids production. The findings of this study suggest that the digestate cake can be used as an effective alternative to the liquid digestate for the inoculation of full-scale anaerobic digesters, reducing the transportation volume by up to 90%.

Day +100 Platelet Count Predicts Survival After Allogeneic Hematopoietic Stem-Cell Transplantation in Children With Hematologic Malignancies

INTRODUCTION

Recovery of platelet count by day 100 after hematopoietic stem-cell transplantation (HSCT) is affected by many factors and has been reported to be a predictor of overall survival (OS) in a variety of diseases and donor types. We investigated the correlation between day +100 platelet count and OS after allogeneic HSCT in a relatively homogeneous cohort of pediatric patients with hematologic malignancies.

PATIENTS AND METHODS

We conducted a retrospective study of 152 consecutive patients who underwent allogeneic HSCT at the Children's Cancer Hospital Egypt between 2009 and 2015 with a minimum follow-up duration of 1 year after transplantation. All eligible patients received myeloablative conditioning, and all had matched related donors. Patients who survived without relapse until day 100 after HSCT were divided into 2 groups: early platelet recovery (EPR; platelet count ≥ 100 × 10⁹/L at day +100 after transplantation) and delayed platelet recovery (DPR; platelet count < 100 × 10⁹/L at day +100 after transplantation).

RESULTS

At day +100, 113 patients (74%) had EPR and 39 patients (26%) had DPR. With a median follow-up of 41 months (range, 12-93 months), 41 patients (27.2%) died, 35 of relapsed disease. The 3-year disease-free survival (DFS) and OS were 68 ± 7.84% and 71.9 ± 7.84%, respectively. The 3-year OS was 77.9% in the EPR group and 57.1% in the DPR group (P = .006). Three-year DFS of the EPR and DPR groups were 73.2 ± 9% and 54.8 ± 16.3%, respectively (P = .02). Incidence of disease relapse for EPR and DPR patients was 22.6% and 39.5%, respectively (P = .04). Multivariate analysis for survival identified DPR as a predictor of decreased survival (P = .002).

CONCLUSION

Patients with a robust platelet count at day 100 are likely to do well. However, patients who do not experience a platelet count of ≥ 100 × 10⁹/L have inferior long-term OS and DFS and may require further evaluation at the day 100 time point.

Bioenergy production data from anaerobic digestion of thermally hydrolyzed organic fraction of municipal solid waste

The presented dataset in this data article provides quantitative data on the production of bioenergy (biogas and biomethane) from mesophilic batch anaerobic digestion (AD) of thermally hydrolyzed organic fraction of municipal solid waste (OFMSW). The discussion and interpretation of the data are provided in another publication entitled “Hydrothermal Pretreatment of Source Separated Organics for Enhanced Solubilization and Biomethane Recovery” (Razavi et al., 2019). The data and information presented in the current data article include (1) the ratio of soluble to particulate chemical oxygen demand (COD) under different thermal hydrolysis condition, (2) the daily measured biogas and biomethane data, (3) the cumulative methane yield data in terms of mL CH₄ produced per gram of volatile suspended solids (VSS) as well as feedstock added, (4) the ultimate methane yield data as well as the relative improvement in methane recovery compared to the control (non-hydrolyzed) digester, (5) the data of first-order organics biodegradation rate constants, (6) the procedure of measuring biogas composition via gas chromatography, (7) the procedure of converting the biogas/methane volume data acquired under the actual experimental condition (mesophilic temperature of 38 °C and atmospheric pressure) to the standard temperature (0 °C) and pressure (1 atm) condition, and (8) the procedure of determining the first-order kinetic rate constants.

Hydrothermal pretreatment of source separated organics for enhanced solubilization and biomethane recovery

The objective of this research was to evaluate the effect of the hydrothermal pretreatment on the solubilization of source separated organics (SSO) as well as the biomethane recovery through the mesophilic batch anaerobic digestion process. For this purpose, the SSO was subjected to fifteen different pretreatment conditions within five different severity index (SI) values (3, 3.5, 4, 4.5, and 5). The pretreatment temperature, holding time, and pressure ranged from 150 to 240 °C, 5 to 30 min, and 476 to 3367 kPa, respectively. The highest solubilization improvement of ∼50% was achieved under the pretreatment condition of "220 °C-10 min-2323 kPa" corresponding to the SI value of 4.5. However, the maximum biomethane production yield of 280 mL/g TCOD_added and biomethane production rate of 30 mL/g TCOD_added were obtained under the less intense pretreatment conditions of "190 °C-20 min-1247 kPa" and "170 °C-30 min-786 kPa", respectively.

2437. Colistin Usage, Do We Need to Worry About Its Toxicity Among Children With Cancer?

Background

Gram-negative bacteria susceptible only to colistin are emerging causes of complicated infections especially in the immunocompromised patients, reviving interest in the use of colistin. The purpose of this study was to test the renal toxicity along with efficacy of a salvage therapy with a colistin among pediatric cancer patients in our hospital.

Methods

A prospective, observational, cohort study was performed from May 2017 to October 2017 in Children’s cancer hospital Egypt 57357. All patients who had Blood Stream Infections due to COS Gram-negative bacteria and received intravenous Colistin were prospectively enrolled. A standardized case form was used to record patient characteristics, including age, sex, weight, underlying comorbidities, type of infection, causative organism and in vitro susceptibility, daily doses and duration of colistin therapy, cumulative dose of colistin, co-administered antibiotics, nephrotoxic agents, and clinical and microbiological responses to therapy, daily serum creatinine clearance, and estimated creatinine clearance were recorded.

Results

One hundred and Thirty-four Blood Stream infectious episodes due to Klebsiella species (pneumoniae and Oxytoca) (32%), and E. coli (68%) were analyzed. All strains were fully susceptible to colistin, with MICs of 0.19–1.5 mg/L. It was employed as combination therapy with carbapenems (69.2%) or aminoglycosides (30.8%). Median duration of treatment was 9 days (range 1–50 days). Clinical and Microbiological cure was observed in 107 cases (80%). Acute kidney injury developed during 5 treatment courses (4%)in combination with Amikacin. No renal replacement therapy was required and subsided within 7 days from Colistin discontinuation. No correlation was found between variation in serum creatinine level (from base line to peak) and daily and cumulative doses of CMS.

Conclusion

Our study shows that in severe infections due to COS Gram-negative bacteria, Colistin had a high efficacy, without significant renal toxicity. Looking into the failure of microbiological cure, we need to further study the possibility of increasing the Colistin with cautious monitoring of renal functions, and Therapeutic Drug monitoring. Furthermore, the bacterial isolates should be studied at the genetic level for resistance.

Disclosures

All authors: No reported disclosures.

Development of the joint Children’s Cancer Hospital Egypt (CCHE-57357) Dana-Farber Boston Children’s Hospital Pediatric Oncology Fellowship Program

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Background: Children diagnosed with cancer in low- and middle-income countries (LMIC) have markedly inferior outcomes compared to those in high income countries. While some of these issues can be resource availability, a major problem is the quality of training and traditional methods of clinical practice where decision making is centered on the most senior person on the team. To ensure real change, highly-trained locally based specialists with a strong emphasis on problem-solving and critical thinking using evidence-based approaches are needed. Methods: The Children’s Cancer Hospital Egypt (CCHE-57357) and Dana-Farber Boston Children’s Hospital (DFBCH) at Harvard Medical School developed a 30 month pediatric oncology fellowship training program following the American Academy of Pediatrics fellowship guidelines. The primary objective of the program was to implement a shared education model to develop highly educated physicians who are able to follow evidence-based approaches and who are committed to sustained practice in LMIC. Results: DFBCH staff provide ongoing education to the fellows through visits to CCHE-57357 every 2-3 months, weekly video sessions with the fellows for case presentation and journal clubs, and weekly conference calls with the fellowship program staff to ensure that the goals and objectives for each fellow and the program are met. Each of the current 15 fellows spend 6 weeks/year in Boston participating in evidence-based multi-disciplinary based rounds; the remainder of the curriculum takes place at CCHE-57357 and incorporates an array of individual, small group and e-learning modules specifically created for the program. Three classes of fellows have been enrolled and the senior class will graduate in the spring of 2017. Conclusions: Training of fellows following the same standards and methods as those applied to North American candidates is feasible and has the potential to advance the quality of education and expertise in LMIC. By focusing on the education of the next generation of clinicians, the opportunity to implement many of the important principles of clinical care can be realized.

Profiling Loss of Heterozygosity Patterns in a Cohort of Favorable Histology Nephroblastoma Egyptian Patients: What is Consistent With the Rest of the World

According to the Fifth National Wilms Tumor Study (NWTS-5), tumor-specific loss of heterozygosity (LOH) for chromosomes 1p and 16q identifies a subset of patients with Wilms tumor (WT) who despite having favorable histology (FH) have a significantly increased risk of relapse and death. We aimed to find out 1p and 16q LOH frequencies in patients with FH-WT as well as its correlation to survival outcome and epidemiologic and clinical characteristics. Data of patients with FH-WT presenting to the National Cancer Institute, Egypt, were retrospectively analyzed. Paraffin blocks were tested for 1p and 16q LOH using polymorphic loci that span the minimal regions of LOH at this area. The study included 100 patients with a median age of 5 years. Thirty-nine patients (39%) showed LOH at 1p (n = 14), 16q (n = 13), or both (n = 12). LOH was most frequently encountered in patients above 10 years (5/5), advanced stages disease (80% of stage V and 50% of stages IV and III each). The 3-year overall survival (OS) and event-free survival (EFS) were significantly lower in patients with double LOH (75% and 50%, respectively), followed by 16q (92% and 54%), in comparison with 1p (93% each) and negative LOH (97% and 100%) cases, respectively (p = 0.001). Combined LOH (1p+16q), followed by 16q LOH alone, was predictive of poorer outcome and was associated with lower OS and EFS in patients with FH-WT. Our results showed a higher-risk disease that would suggest the need for an intensified upfront therapy in this group of patients.

Prevalence and management of ovarian venous insufficiency in the presence of leg venous insufficiency

Objective: The correlation between ovarian venous insufficiency and lower limb venous insufficiency remains poorly understood. Clinically, incompetent ovarian veins in association with lower extremity varicose veins are suspected when leg varicose veins are found in atypical distributions. Such distributions include upper lateral or posterior thigh, on the buttocks, crossing the inguinal ligament, and also in the vulval or perineal regions. The aim of this study was to determine the prevalence of ovarian venous insufficiency in those with clinically suspicious varicose veins, and to assess the effectiveness of ovarian venous embolization/ligation in treating this condition.

Methods: Between June 2001 and December 2004, 424 female patients with lower limb superficial venous insufficiency were seen by a single vascular surgeon. These patients were clinically assessed, and those with atypical varicose veins were investigated with venous duplex examination and magnetic resonance imaging (MRI) venography. Patients with proven ovarian venous insufficiency were offered venography with a view to embolization or laparoscopic ligation.

Results: A total of seven patients were clinically suspected of having ovarian venous insufficiency, of which three had recurrent varicose veins (42.9%). Of these, six were confirmed on MRI venography with the left side being more affected than the right; one of them had an occluded vena cava, three were treated by embolization, and two had laparoscopic ligation.

Discussion: The prevalence of clinically detectable ovarian venous insufficiency in association with lower extremity varicose veins is in the region of 1.65%. Compared with the estimated prevalence of incidental ovarian venous insufficiency of 10–47%, this suggests that only a minority of incompetent ovarian veins will present with clinically detectable lower limb venous insufficiency. In our opinion, patients with signs suggestive of ovarian venous insufficiency in association with lower limb venous insufficiency should have their ovarian insufficiency controlled prior to embarking on limb venous surgery.

Comparison of toxicity following different conditioning regimens (busulfan/melphalan and carboplatin/etoposide/melphalan) for advanced stage neuroblastoma: Experience of two transplant centers

The outcome for advanced neuroblastoma has improved with combined modality therapy: induction chemotherapy, surgery, and consolidation with high-dose chemotherapy/autologous HSCT, followed by local radiation, cisretinoic acid, and recently antibody therapy. In the United States, the most common conditioning regimen is CEM, while in Europe/Middle East, Bu/Mel has been widely used; it remains unclear which regimen has the best outcome. Assess renal, hepatic, and infectious toxicity through Day+100 in 2 different regimens. Retrospective comparison between CEM-DFCHCC Boston and Bu/Mel- CCHE-57357. Thirty-five patients, median age 4, in Boston (2007-2011) and 38 patients, median age 3, in Cairo (2009-2011). Renal toxicity; creatinine was significantly higher in CEM than Bu/Mel: 57% (median day+90) vs. 29% (median>day+100), p = 0.004. One CEM patient died from renal dialysis at day+19. Hepatic toxicity was significantly higher in CEM than Bu/Mel: 80% (median day+26) vs. 58% (median day+60), p = 0.04. In infectious complications with CEM 14%, bacteremia (n = 4) and fungemia (n = 1), 3 had culture-negative sepsis requiring vasopressors. With Bu/Mel 18%, bacteremia (n = 7), none required pressors, p = 0.4. Bu/Mel was associated with less acute hepatic and renal toxicity and thus may be preferable for preserving organ functions.

Effect of extreme pump pulse reshaping on intense terahertz emission in lithium niobate at multimilliJoule pump energies

We report on terahertz (THz) generation via optical rectification in a room-temperature lithium niobate crystal under variable pump pulse durations, ranging from 100 to 300 fs, at 800 nm center wavelength. The efficiency for the process is predicted to have an order of magnitude increase when longer duration Fourier-limited pump pulses are used. Our results confirm this increase in efficiency, and we report a record 800 nm pump energy conversion efficiency of 0.35% with a saturation at >240  fs pulse duration. While promising, our findings show a series of key problems that must be overcome before the theoretical limit can be achieved, including the influence of the pump bandwidth broadening due to the cascaded nonlinearity taking place within the crystal.

Synthesis of highly active thin film based on TiO2 nanomaterial for self-cleaning application

Highly active self-cleaning surfaces were prepared from hydrothermally treated TiO2 nanomaterials for different times (0, 12, 24 and 36 h) under acidic condition. TiO2 thin films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM). TiO2 thin film (hydrothermal 24h) exhibited hybrid morphology from accumulated plates, clusters, rods and spheres. The photo self-cleaning activity in term of quantitative determination of the active oxidative species (OH) produced on the thin film surfaces was evaluated using fluorescent probe method. The results show that, the highly active thin film is the hydrothermally treated for 24 h at 200 °C. The structural, morphology and photoactivity properties of nano-TiO2 thin films make it promising surfaces for self-cleaning application. Mineralization of commercial textile dye (Remazol Red RB-133, RR) from highly active TiO2 thin film surface was applied. Moreover, the durability of this nano-TiO2 thin film (hydrothermal 24h) was studied.

Photo-induced self-cleaning and sterilizing activity of Sm3+ doped ZnO nanomaterials

Highly active samarium doped zinc oxide self-cleaning and biocidal surfaces (x mol% Sm(3+)/ZnO where x=0, 1, 2 and 4 mol%) with crystalline porous structures were synthesized by hydrothermal method. Sm(3+)/ZnO thin films were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), energy dispersive spectroscopic (EDS), UV-visible diffuse reflectance and fluorescence (FL) spectroscopy. The combination between doping and hydrothermal treatments significantly altered the morphology of ZnO into rod and plate-like nanoshapes structure and enhanced its absorption and emission of ultraviolet radiation. The photo-activity in term of quantitative determination of the active oxidative species (()OH) produced on the thin film surfaces was evaluated using fluorescent probe method. The results showed that, the hydrothermally treated 2.0 mol% Sm(3+)/ZnO film (S2) is the highly active one. The optical, structural, morphology and photo-activity properties of the highly active thin film (S2) make it promising surface for self-cleaning and sterilizing applications.

Carrier density dependence of the nonlinear absorption of intense THz radiation in GaAs

We study the carrier density dependence of nonlinear terahertz (THz) absorption due to field-induced intervalley scattering in photoexcited GaAs using the optical-pump/THz-probe technique. The intervalley scattering in GaAs is strongly dependent on the photo-carrier density. As the carrier density is increased from 1 × 10(17) to 4.7 × 10(17) cm(-3), the nonlinear absorption bleaching increases. However, if the carrier density is increased further above 4.7 × 10(17) cm(-3), the trend reverses and the bleaching is reduced. The initial increase in absorption bleaching is because, unlike low THz field, high THz field experiences intervalley scattering and nonparabolicity of the conduction band. On the other hand, a simple electron transport model shows that the reduction in intervalley scattering is mainly due to the increase in the electron-hole scattering rate with the increase in the carrier density. This increase in the electron-hole scattering rate limits the maximum kinetic energy attainable by the electrons and thus reduces the observed nonlinear absorption.

Ultrasound-guided foam sclerotherapy within a rolling treatment programme is an effective low-cost treatment for superficial venous insufficiency

AIMS

To review the results and cost of a rolling ultrasound-guided foam sclerotherapy (UGFS) treatment programme for patients with chronic superficial venous insufficiency.

METHOD

A prospective study of a rolling treatment programme where patients were offered unlimited follow-up at intervals of 6-8 weeks and further (top up) UGFS when necessary, until occlusion criteria were met.

RESULTS

A total of 213 lower limbs with complete follow-up were included in the study. Median (range) age was 57 (16-94) years, maximum diameter of varicose vein was 10 (3-18) mm, C of CEAP (clinical, aetiological, anatomical and pathological elements) was 4 (2-6), number of treatment sessions was one (1-4) and follow-up was three (1.5-33) months. Satisfactory occlusion could not be achieved in nine (4%) limbs. The ratio of odds (95% CI) for requiring more than one treatment session was 3.58 (1.46-8.77), P = 0.002 for great saphenous varicosity and 2.11 (1.13-3.94), P = 0.015 for age 50 or more. There were 20 (9.3%) immediate and 63 (29.5%) delayed adverse effects. All were minor except for one cutaneous nerve injury, one pulmonary embolism and one infected haematoma. The ratio for odds (95% CI) for post-treatment skin discolouration was 2.59 (1.14-5.87), P = 0.017 for women and 1.32 (1.02-1.71), P = 0.032 for increasing sclerosant volume used. Service line costing per completed treatment episode was £115.22 (€130.07, $188.60).

CONCLUSION

UGFS in a rolling treatment programme is safe and can achieve high occlusion rates at a low cost. Patients above the age of 50 with great saphenous varicosity are likely to require more than one treatment session.

Comparison between killed and living probiotic usage versus placebo for the prevention of necrotizing enterocolitis and sepsis in neonates

The aim of the study is to compare the role of killed (KP) Lactobacillus acidophilus with living (LP) in reducing incidence of sepsis (NS) and necrotizing enterocolitis (NEC) in neonates. Randomized double blind placebo study, included 150 neonates admitted to NICU at day 1, sixty received oral (LP) and 60 received (KP) and 30 received placebo. One gram of stools was collected on admission, at day 7, at end of the study, as well as on suspected NEC or NS and was sent for culture.

RESULTS

LP and KP were preventive factors for NEC with absolute risk reduction (AAR) 16, 15%, respectively and 18% for NS compared to placebo. Incidence of NEC and NS did not differ significantly between neonates supplemented with LP and those with KP. Preterm neonates supplemented with KP showed significantly lower incidence of NEC compared to placebo, while incidence of NS showed no significant difference between both groups. There is significant reduction in NS and NEC among neonates with positive Lactobacillus colonization of gut compared to those none colonized at day 7 (27.9 vs. 85.9%, 0 vs. 7.8%) and at day 14 (48.7 vs. 91.7% for NS and 0 vs. 20.8% for NEC). Overall comparison between the three groups showed statistical significant reduction in the incidence of NEC. Present conclusions are that early gut colonization with beneficial bacteria lowers the incidence of NEC and NS. KP retained similar benefits to live bacteria.