Enhancing Cementitious Composites with Functionalized Graphene Oxide-Based Materials: Surface Chemistry and Mechanisms

Graphene oxide-based materials (GOBMs) have been widely explored as nano-reinforcements in cementitious composites due to their unique properties. Oxygen-containing functional groups in GOBMs are crucial for enhancing the microstructure of cementitious composites. A better comprehension of their surface chemistry and mechanisms is required to advance the potential applications in cementitious composites of functionalized GOBMs. However, the mechanism by which the oxygen-containing functional groups enhance the response of cementitious composites is still unclear, and controlling the surface chemistry of GOBMs is currently constrained. This review aims to investigate the reactions and mechanisms for functionalized GOBMs as additives incorporated in cement composites. A variety of GOBMs, including graphene oxide (GO), hydroxylated graphene (HO-G), edge-carboxylated graphene (ECG), edge-oxidized graphene oxide (EOGO), reduced graphene oxide (rGO), and GO/silane composite, are discussed with regard to their oxygen functional groups and interactions with the cement microstructure. This review provides insight into the potential benefits of using GOBMs as nano-reinforcements in cementitious composites. A better understanding of the surface chemistry and mechanisms of GOBMs will enable the development of more effective functionalization strategies and open up new possibilities for the design of high-performance cementitious composites.

Enhanced Probe Bonding and Fluorescence Properties through Annealed Graphene Oxide Nanosheets

Graphene oxide (GO) has been widely used in biological sensing studies because of its excellent physical and chemical properties. In particular, the rich functional groups on the surface of GO can effectively enhance the bonding of biomolecules and serve as an efficient sensing substrate. However, when biomolecules are labeled with fluorescence, the GO interface affects the biomolecules by reducing the fluorescence properties and limiting their applications in biosensing. Here, we establish an annealed GO (aGO) substrate through the annealing process, which can effectively increase the bonding amount of a DNA probe because of the accumulation of oxygen atoms on the surface without significantly damaging the nanosheet structure. Furthermore, we prove that the aGO substrate can effectively maintain its fluorescence performance and stability by exposing more graphic domains. Overall, this study successfully verifies that GO's interface annealing modification can be used as an alternative innovative interface application in biosensing.

Prenatal diagnosis and molecular cytogenetic characterization of a small supernumerary marker chromosome derived from chromosome 15 in a pregnancy associated with recurrent Down syndrome

OBJECTIVE

We present prenatal diagnosis and molecular cytogenetic characterization of a small supernumerary marker chromosome (sSMC) derived from chromosome 15 in a pregnancy associated with recurrent Down syndrome.

CASE REPORT

A 33-year-old, gravida 4, para 2, woman underwent amniocentesis at 16 weeks of gestation because of a previous child with Down syndrome and a karyotype of 46,XY,der(14;21)(q10; q10),+21. In this pregnancy, amniocentesis revealed a karyotype of 47,XX,+21[12]/48,XX,+21,+mar[3]. The parental karyotypes were normal. The pregnancy was terminated, and a malformed fetus was delivered with characteristic craniofacial appearance of Down syndrome and hypoplastic middle phalanx of the fifth fingers. The placenta had a karyotype of 47,XX,+21[37]/48,XX,+21,+mar[3]. The umbilical cord had a karyotype of 47,XX,+21[38]/48,XX,+21,+mar[2]. In addition to trisomy 21, array comparative genomic hybridization (aCGH) on the DNA extracted from umbilical cord revealed 40∼50% mosaicism for a 2.604-Mb duplication of 15q25.2-q25.3, or arr 15q25.2q25.3 (83,229,665-85,834,131) × 2.4 [GRCh37 (hg19)] encompassing 19 Online Mendelian Inheritance in Man (OMIM) genes. Quantitative fluorescent polymerase chain reaction (QF-PCR) using the DNAs extracted from cultured amniocytes and parental bloods revealed maternal origin of the sSMC(15) and the extra chromosome 21.

CONCLUSION

aCGH is useful for identification of the nature of sSMC, and QF-PCR is useful for determination of the parental origin of the aberrant chromosomes.

P–497 Anxiety, depression and sexual dysfunction among women with genital diseases

Study question

How is the prevalence of anxiety, depression and sexual dysfunction among Chinese women who is suffering from genital diseases? What is the relationship among their anxiety, depression and sexual dysfunction?

Summary answer

Anxiety, depression and sexual dysfunction symptoms were self-reported by the participants. Besides, their anxiety, depression and sexual dysfunction were inter-correlated.

What is known already

Reduced sexual activity and dysfunctional problems are highly prevalent in females. Approximately 43% of American women reported experiencing sexual problems.

Women who are facing pressure on childbirth, may be more likely to have mental health problems. Some studies have shown that having gynecological disease can lead to anxiety, depression and sexual dysfunction. However, the mental health of females who are suffering from genital diseases has been little studied.

Study design, size, duration

The investigation was carried out from March to November, 2020. Participants were recruited in the Hong Kong University-Shenzhen Hospital, located in Shenzhen, China. 135 patients were approached while 116 agreed to join the survey.

Participants/materials, setting, methods

116 women (35.42±8.19 years old) with a diagnosis of fallopian tube disease, ovarian benign disease or uterine disease voluntarily filled a questionnaire which contains the Female Sexual Function Index–6 Items (FSFI–6) and the Hospital Anxiety and Depression Scale (HADS). Descriptive analysis and stepwise regression were used to present participants’ self-reported anxiety, depression, and sexual dysfunction problems, as well as the relationship among their anxiety, depression, and sexual dysfunction.

Main results and the role of chance

25% of the participants reported anxiety symptoms; 9.5% of the women reported depressive symptoms; while 37.3% reported sexual dysfunction problems. Anxiety (p < 0.001) was significantly associated with depression. Depressive symptom can significantly predict sexual dysfunction (p < 0.05) while anxiety was not associated with sexual dysfunction (p > 0.05). Targeted interventions are needed to improve the mental health status of women with genital diseases in China.

Limitations, reasons for caution

This study can only present mental health status of this population. To better show the odds ratio of mental health problems, a case-control study design is needed. Besides, future qualitative or longitudinal studies are needed to detect the risk factors for the poor mental health of women with genital diseases.

Wider implications of the findings: Reduced sexual activity and dysfunctional problems are highly prevalent in females with genital diseases. Sexuality is an important element in patients’ quality of life. For female patients with genital diseases, we should not only treat their physical symptoms, but also guide and treat patients in mental ways.

Trial registration number

ChiCTR2000031343

Long-term prognosis of vascular access in hemodialysis patients with systemic lupus erythematosus: a retrospective cohort study

Patients with systemic lupus erythematosus (SLE) have a higher risk of vascular complications. This retrospective cohort study aimed to analyze the differences in the risk of arteriovenous fistula or graft (AVF/AVG) dysfunction in hemodialysis patients with and without SLE from Taiwan's National Health Insurance Database over a 10-year period. AVF/AVG dysfunction is defined as the occurrence of the first episode of intervention after vascular access creation. A total of 1366 HD patients with SLE had higher incidence rates of AVF/AVG dysfunction than 4098 non-SLE HD patients in the following 4 periods: (1) after 1 year (incidence rates = 15.21% and 13.01%, respectively; subdistribution hazard ratio (SHR) = 1.16; P = 0.007), (2) 1st-to-10th-year period (15.36% and 13.25%; SHR = 1.16; P = 0.007), (3) 5th-to-10th-year period (11.91% and 8.1%; SHR = 1.42; P = 0.003), and (4) overall period (23.53% and 21.66%; SHR = 1.09; P = 0.027). In conclusion, there were significantly higher incidence rates of AVF/AVG dysfunction in SLE patients during the long-term follow-up period. Vascular access function should be monitored regularly by clinical examinations, especially after 1 year and during 5 to 10 years, to improve AVF/AVG patency and dialysis adequacy in SLE patients undergoing maintenance hemodialysis.

Centre for Youth Research and Practice: Social Impact Assessment Results

Purpose: This article outlines the objective and structure of the Center for Youth Research and Practice (CYRP), its contributions toward youth research and practices, importance of the linkages that the CYRP has cultivated between research and practice, the facilitation of knowledge exchange with local and global institutions and professionals, and its role in future endeavors.Method: A social impact assessment has been implemented to address the intervention and the outcome based on the contributions of the CYRP to youth research and practices.Results: From this, the work of the CYRP on youth research and practices is concluded to have significant social impacts at the individual, social, organizational, and global levels. The work has found that the quality of life, self-esteem, involvement in society, empowerment through social capacity building, organizational development, and providing an international hub are crucial for youth development and wellbeing.Discussion: Hitherto, the CYRP has published over a hundred journal articles and held nearly 200 events including training courses, workshops, seminars and a conference. Over 6000 participants have taken part in these events and more than 60 institutions have collaborated with the CYRP to exchange knowledge on youth research and practices. The work of the CYRP as a whole has facilitated the participation of different individuals and organizations. In essence, the work of the CYRP has provided important grounds to initiate its role as an international hub as the CYRP is now considered as a center of significance in youth research and practices for Chinese societies in the East Asia region.

Prognosis of Vascular Access in Haemodialysis Patients with Autosomal Dominant Polycystic Kidney Disease

Vascular diseases are commonly observed in patients with autosomal dominant polycystic kidney disease (ADPKD). We aim to investigate the differences in the risk for arteriovenous fistula or graft (AVF/AVG) dysfunction in haemodialysis (HD) patients with and without ADPKD. 557 ADPKD and 1671 non-ADPKD patients were enrolled in the study after propensity score matching. The primary outcome measure is the incidence rate of AVF/AVG dysfunction. The incidence rates and risks of AVF/AVG dysfunction (per 100 person-years) for ADPKD and non-ADPKD patients were (1) 38.83 and 48.99 [SHR = 0.79, P = 0.137], respectively, for within 90 days, (2) 45.85 and 51.31 [SHR = 0.90, P = 0.300], respectively, for within 180 days, (3) 44.42 and 41.40 [SHR = 1.08, P = 0.361], respectively, for within the first year, (4) 27.38 and 24.69 [SHR = 1.09, P = 0.168], respectively, for within 5 years, (5) 17.35 and 13.80 [SHR = 1.19, P = 0.045], respectively, for between the 1st and 10th year, and (6) 25.40 and 21.22 [SHR = 1.14, P = 0.031], respectively, for all periods. ADPKD patients had lower incidence rates of AVF/AVG dysfunction within the first 180 days than non-ADPKD patients, but presented a higher incidence rate after 1 year of AVF/AVG creation and onwards.

The many facets of neuropathic arthropathy

Neuropathic arthropathy, also known as Charcot arthropathy, refers to progressive and occasionally rapid joint destruction that results from underlying disorders of the nervous system. This pictorial essay aims to illustrate various radiologic findings in neuropathic arthropathy using various examples in the upper and lower limbs and in the spine. Pearls for radiologic diagnosis, clinical differential considerations and possible complications are discussed individually for each joint. MR imaging techniques for differentiating infection and neuropathic arthropathy are explained with examples. Management issues are outlined.

Role of PGRMC1 in cell physiology of cervical cancer

AIMS

The most frequent cancers among women worldwide. The mortality of cervical cancer has declined significantly primarily due to the widespread use of Pap smear tests as a screening test and therapeutic vaccination. However, cervical cancer still remains a severe disease among the female population, as the prognosis of metastatic cervical cancer is very poor.

KEY METHODS

In this study, we performed 2D-DIGE and MALDI-TOF/TOF MS to analyze differentially expressed proteins between HeLa and invasive HeLa-I5 cells..

KEY FINDINGS

According to our proteomics data, 68 differentially expressed proteins between the HeLa and HeLa-I5 cells were identified. One of these differentially expressed proteins, Progesterone receptor membrane component 1 (PGRMC1), was selected as a candidate for further studies. To correlate the role of PGRMC1 with cellular migration and cancer progression, small interfering RNA (siRNA) was used to knockdown the expression of PGRMC1. Similar function of PGRMC1 was also observed in two other cervical cancer lines, CaSki and ME-180.

SIGNIFICANCE

PGRMC1 plays an essential role in regulating cancer progression and metastasis of cervical cancer cells, thus serving as a potential therapeutic target for cervical cancer.

Proteomic investigating the cooperative lethal effect of EGFR and MDM2 inhibitors on ovarian carcinoma

With the concept of precision medicine, combining multiple molecular-targeting therapies has brought new approaches to current cancer treatments. Malfunction of the tumor suppressor protein, p53 is a universal hallmark in human cancers. Under normal conditions, p53 is degraded through an ubiquitin-proteosome pathway regulated by its negative regulator, MDM2. In contrast, cellular stress such as DNA damage will activate p53 to carry out DNA repair, cell cycle arrest, and apoptosis. In this study, we focused on ovarian carcinoma with high EGFR and MDM2 overexpression rate. We assessed the effects of combined inhibition by MDM2 (JNJ-26854165) and EGFR (gefitinib) inhibitors on various ovarian cell lines to determine the importance of these two molecular targets on cell proliferation. We then used a proteomic strategy to investigate the relationship between MDM2 and EGFR inhibition to explore the underlying mechanisms of how their combined signaling blockades work together to exert cooperative inhibition. Our results demonstrated that all four cell lines were sensitive to both individual and combined, MDM2 and EGFR inhibition. The proteomic analysis also showed that gefitinib/JNJ-treated CAOV3 cells exhibited downregulation of proteins involved in nucleotide biosynthesis such as nucleoside diphosphate kinase B (NME2). In conclusion, our study showed that the combined treatment with JNJ and gefitinib exerted synergistic inhibition on cell proliferation, thereby suggesting the potential application of combining MDM2 inhibitors with EGFR inhibitors for enhancing efficacy in ovarian cancer treatment.

Macroscopically constrained Wang-Landau method for systems with multiple order parameters and its application to drawing complex phase diagrams

A generalized approach to Wang-Landau simulations, macroscopically constrained Wang-Landau, is proposed to simulate the density of states of a system with multiple macroscopic order parameters. The method breaks a multidimensional random-walk process in phase space into many separate, one-dimensional random-walk processes in well-defined subspaces. Each of these random walks is constrained to a different set of values of the macroscopic order parameters. When the multivariable density of states is obtained for one set of values of fieldlike model parameters, the density of states for any other values of these parameters can be obtained by a simple transformation of the total system energy. All thermodynamic quantities of the system can then be rapidly calculated at any point in the phase diagram. We demonstrate how to use the multivariable density of states to draw the phase diagram, as well as order-parameter probability distributions at specific phase points, for a model spin-crossover material: an antiferromagnetic Ising model with ferromagnetic long-range interactions. The fieldlike parameters in this model are an effective magnetic field and the strength of the long-range interaction.

YM500v3: a database for small RNA sequencing in human cancer research

We previously presented the YM500 database, which contains >8000 small RNA sequencing (smRNA-seq) data sets and integrated analysis results for various cancer miRNome studies. In the updated YM500v3 database (http://ngs.ym.edu.tw/ym500/) presented herein, we not only focus on miRNAs but also on other functional small non-coding RNAs (sncRNAs), such as PIWI-interacting RNAs (piRNAs), tRNA-derived fragments (tRFs), small nuclear RNAs (snRNAs) and small nucleolar RNAs (snoRNAs). There is growing knowledge of the role of sncRNAs in gene regulation and tumorigenesis. We have also incorporated >10 000 cancer-related RNA-seq and >3000 more smRNA-seq data sets into the YM500v3 database. Furthermore, there are two main new sections, ‘Survival' and ‘Cancer', in this updated version. The ‘Survival’ section provides the survival analysis results in all cancer types or in a user-defined group of samples for a specific sncRNA. The ‘Cancer’ section provides the results of differential expression analyses, miRNA–gene interactions and cancer miRNA-related pathways. In the ‘Expression’ section, sncRNA expression profiles across cancer and sample types are newly provided. Cancer-related sncRNAs hold potential for both biotech applications and basic research.

Genetic polymorphisms of the human cytomegalovirus UL144 gene in colorectal cancer and its association with clinical outcome

Human cytomegalovirus (HCMV) has been increasingly detected in colorectal cancer (CRC), and genetic polymorphisms in HCMV affect its pathogenesis. This study aimed to investigate HCMV genetic polymorphisms in CRC and its correlation with the clinical outcomes. We performed PCR and sequencing of a viral immunomodulatory gene, UL144, in clinical isolates and CRC specimens. The nucleotide and amino acid sequences were aligned, and a phylogenetic tree was constructed. The clinical, pathological and survival data were compared among tumours with different UL144 genotypes. HCMV was detected in 49 (47.8 %) of the tumour specimens. Genotype A predominated in 43 samples (22/43; 51.2 %) with successful sequencing, followed by genotype B (13/43; 30.2 %) and genotype C (8/43; 18.6 %). The genotypic distribution was similar to that of the clinical isolates and those reported in other Asian populations. The amino acid sequence of genotype B was the most conserved. For stage II and III CRC patients with HCMV-positive tumours, disease-free survival (DFS) varied among the three major genotypes (P50.0046). The presence of genotype B virus in the tumours was associated with a shorter DFS and independently predicted tumour recurrence in a multivariate Cox proportional hazards model (hazard ratio, 5.79; 95 % confidence interval, 1.30–25.81; P50.021). By reverse transcription PCR, tumour samples with genotype B viruses had the highest rate of UL144 expression. Our results suggest that genetic polymorphisms of HCMV UL144 are associated with clinical outcome in CRC and that HCMV may play an immunomodulatory role in the tumour microenvironment of CRC.

Association of Genetic Polymorphisms of Renin-Angiotensin-Aldosterone System-Related Genes with Arterio-Venous Fistula Malfunction in Hemodialysis Patients

Hemodialysis (HD) is the most commonly-used renal replacement therapy for patients with end-stage renal disease worldwide. Arterio-venous fistula (AVF) is the vascular access of choice for HD patients with lowest risk of infection and thrombosis. In addition to environmental factors, genetic factors may also contribute to malfunction of AVF. Previous studies have demonstrated the effect of genotype polymorphisms of angiotensin converting enzyme on vascular access malfunction. We conducted a multicenter, cross-sectional study to evaluate the association between genetic polymorphisms of renin-angiotensin-aldosterone system and AVF malfunction. Totally, 577 patients were enrolled. Their mean age was 60 years old and 53% were male. HD patients with AVF malfunction had longer duration of HD (92.5 ± 68.1 vs. 61.2 ± 51.9 months, p < 0.001), lower prevalence of hypertension (44.8% vs. 55.3%, p = 0.025), right-sided (31.8% vs. 18.4%, p = 0.002) and upper arm AVF (26.6% vs. 9.7%, p < 0.001), and higher mean dynamic venous pressure (DVP) (147.8 ± 28.3 vs. 139.8 ± 30.0, p = 0.021). In subgroup analysis of different genders, location of AVF and DVP remained significant clinical risk factors of AVF malfunction in univariate and multivariate binary logistic regression in female HD patients. Among male HD patients, univariate binary logistic regression analysis revealed that right-side AVF and upper arm location are two important clinical risk factors. In addition, two single nucleotide polymorphisms (SNPs), rs275653 (Odds ratio 1.90, p = 0.038) and rs1492099 (Odds ratio 2.29, p = 0.017) of angiotensin II receptor 1 (AGTR1), were associated with increased risk of AVF malfunction. After adjustment for age and other clinical factors, minor allele-containing genotype polymorphisms (AA and CA) of rs1492099 still remained to be a significant risk factor of AVF malfunction (Odds ratio 3.63, p = 0.005). In conclusion, we demonstrated that rs1492099, a SNP of AGTR1 gene, could be a potential genetic risk factor of AVF malfunction in male HD patients.

Small RNA and RNA-IP Sequencing Identifies and Validates Novel MicroRNAs in Human Mesenchymal Stem Cells

Organ regeneration therapies using multipotent mesenchymal stem cells (MSCs) are currently being investigated for a variety of common complex diseases. Understanding the molecular regulation of MSC biology will benefit regenerative medicine. MicroRNAs (miRNAs) act as regulators in MSC stemness. There are approximately 2500 currently known human miRNAs that have been recorded in the miRBase v21 database. In the present study, we identified novel microRNAs involved in MSC stemness and differentiation by obtaining the global microRNA expression profiles (miRNomes) of MSCs from two anatomical locations bone marrow (BM-MSCs) and umbilical cord Wharton's jelly (WJ-MSCs) and from osteogenically and adipogenically differentiated progenies of BM-MSCs. Small RNA sequencing (smRNA-seq) and bioinformatics analyses predicted that 49 uncharacterized miRNA candidates had high cellular expression values in MSCs. Another independent batch of Ago1/2-based RNA immunoprecipitation (RNA-IP) sequencing datasets validated the existence of 40 unreported miRNAs in cells and their associations with the RNA-induced silencing complex (RISC). Nine of these 40 new miRNAs were universally overexpressed in both MSC types; nine others were overexpressed in differentiated cells. A novel miRNA (UNI-118-3p) was specifically expressed in BM-MSCs, as verified using RT-qPCR. Taken together, this report offers comprehensive miRNome profiles for two MSC types, as well as cells differentiated from BM-MSCs. MSC transplantation has the potential to ameliorate degenerative disorders and repair damaged tissues. Interventions involving the above 40 new microRNA members in transplanted MSCs may potentially guide future clinical applications.

Identification of protein expression alterations in gefitinib-resistant human lung adenocarcinoma: PCNT and mPR play key roles in the development of gefitinib-associated resistance

Gefitinib is the first-line chemotherapeutic drug for treating non-small cell lung cancer (NSCLC), which comprises nearly 85% of all lung cancer cases worldwide. However, most patients eventually develop drug resistance after 12-18 months of treatment. Hence, investigating the drug resistance mechanism and resistance-associated biomarkers is necessary. Two lung adenocarcinoma cell lines, PC9 and gefitinib-resistant PC9/Gef, were established for examining resistance mechanisms and identifying potential therapeutic targets. Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry were used for examining global protein expression changes between PC9 and PC9/Gef. The results revealed that 164 identified proteins were associated with the formation of gefitinib resistance in PC9 cells. Additional studies using RNA interference showed that progesterone receptor membrane component 1 and pericentrin proteins have major roles in gefitinib resistance. In conclusion, the proteomic approach enabled identifying of numerous proteins involved in gefitinib resistance. The results provide useful diagnostic markers and therapeutic candidates for treating gefitinib-resistant NSCLC.

Angiographic factors associated with haemorrhagic presentation of brain arteriovenous malformation in a Chinese paediatric population

OBJECTIVE

To identify specific angiographic factors associated with haemorrhagic presentation of brain arteriovenous malformation in Chinese paediatric patients.

DESIGN

Retrospective cross-sectional observational study.

SETTING

Four locoregional tertiary neurosurgical centres in Hong Kong: Queen Elizabeth Hospital, Tuen Mun Hospital, Kwong Wah Hospital, and Pamela Youde Nethersole Eastern Hospital.

PATIENTS

Patients aged 18 years or younger who underwent pretreatment digital subtraction angiography for brain arteriovenous malformation between 1 January 2005 and 31 July 2013 were included. Patients were divided into haemorrhagic and non-haemorrhagic groups based on the initial presentation. Pretreatment digital subtraction angiographies were independently reviewed by two experienced neuroradiologists.

MAIN OUTCOME MEASURES

The following parameters were evaluated for their association with haemorrhagic presentation by univariate and multivariate analyses: nidus location, nidus size, nidus morphology (diffuse or compact); origin and number of arterial feeders; venous drainage; number of draining veins; presence of aneurysms, venous varices, and venous stenosis.

RESULTS

A total of 67 children and adolescents (28 male, 39 female) with a mean age of 12 years were included. Of them, 52 (78%) presented with haemorrhage. Arteriovenous malformation size (P=0.004) and morphology (P=0.05) were found to be associated with haemorrhagic presentation by univariate analysis. Small arteriovenous malformation nidus size and diffuse nidal morphology were identified as independent risk factors for haemorrhage by multivariate analysis.

CONCLUSION

Smaller arteriovenous malformation size and diffuse nidal morphology are angiographic factors independently associated with haemorrhagic presentation. Bleeding risk is important in determining the therapeutic approach (aggressive vs conservative) and timeframe, particularly in paediatric patients.

Mitochondrial proteomics with siRNA knockdown to reveal ACAT1 and MDH2 in the development of doxorubicin-resistant uterine cancer

Mitochondria are key organelles in mammary cells in responsible for a number of cellular functions including cell survival and energy metabolism. Moreover, mitochondria are one of the major targets under doxorubicin treatment. In this study, low-abundant mitochondrial proteins were enriched for proteomic analysis with the state-of-the-art two-dimensional differential gel electrophoresis (2D-DIGE) and matrix-assistant laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) strategy to compare and identify the mitochondrial protein profiling changes in response to the development of doxorubicin resistance in human uterine cancer cells. The mitochondrial proteomic results demonstrate more than fifteen hundred protein features were resolved from the equal amount pooled of three purified mitochondrial proteins and 101 differentially expressed spots were identified. In which, 39 out of these 101 identified proteins belong to mitochondrial proteins. Mitochondrial proteins such as acetyl-CoA acetyltransferase (ACAT1) and malate dehydrogenase (MDH2) have not been reported with the roles on the formation of doxorubicin resistance in our knowledge. Further studies have used RNA interference and cell viability analysis to evidence the essential roles of ACAT1 and MDH2 on their potency in the formation of doxorubicin resistance through increased cell viability and decreased cell apoptosis during doxorubicin treatment. To sum up, our current mitochondrial proteomic approaches allowed us to identify numerous proteins, including ACAT1 and MDH2, involved in various drug-resistance-forming mechanisms. Our results provide potential diagnostic markers and therapeutic candidates for the treatment of doxorubicin-resistant uterine cancer.

Monte Carlo simulations of the critical properties of a Ziff-Gulari-Barshad model of catalytic CO oxidation with long-range reactivity

The Ziff-Gulari-Barshad (ZGB) model, a simplified description of the oxidation of carbon monoxide (CO) on a catalyst surface, is widely used to study properties of nonequilibrium phase transitions. In particular, it exhibits a nonequilibrium, discontinuous transition between a reactive and a CO poisoned phase. If one allows a nonzero rate of CO desorption (k), the line of phase transitions terminates at a critical point (k(c)). In this work, instead of restricting the CO and atomic oxygen (O) to react to form carbon dioxide (CO(2)) only when they are adsorbed in close proximity, we consider a modified model that includes an adjustable probability for adsorbed CO and O atoms located far apart on the lattice to react. We employ large-scale Monte Carlo simulations for system sizes up to 240×240 lattice sites, using the crossing of fourth-order cumulants to study the critical properties of this system. We find that the nonequilibrium critical point changes from the two-dimensional Ising universality class to the mean-field universality class upon introducing even a weak long-range reactivity mechanism. This conclusion is supported by measurements of cumulant fixed-point values, cluster percolation probabilities, correlation-length finite-size scaling properties, and the critical exponent ratio β/ν. The observed behavior is consistent with that of the equilibrium Ising ferromagnet with additional weak long-range interactions [T. Nakada, P. A. Rikvold, T. Mori, M. Nishino, and S. Miyashita, Phys. Rev. B 84, 054433 (2011)]. The large system sizes and the use of fourth-order cumulants also enable determination with improved accuracy of the critical point of the original ZGB model with CO desorption.

miRNome traits analysis on endothelial lineage cells discloses biomarker potential circulating microRNAs which affect progenitor activities

Background

Endothelial progenitor cells (EPCs) play a fundamental role in not only blood vessel development but also post-natal vascular repair. Currently EPCs are defined as early and late EPCs based on their biological properties and their time of appearance during in vitro culture. Both EPC types assist angiogenesis and have been linked to ischemia-related disorders, including coronary artery disease (CAD).

Results

We found late EPCs are more mobile than early EPCs and matured endothelial cells (ECs). To pinpoint the mechanism, microRNA profiles of early EPCs late EPCs, and ECs were deciphered by small RNA sequencing. Obtained signatures made up of both novel and known microRNAs, in which anti-angiogenic microRNAs such as miR-221 and miR-222 are more abundant in matured ECs than in late EPCs. Overexpression of miR-221 and miR-222 resulted in the reduction of genes involved in hypoxia response, metabolism, TGF-beta signalling, and cell motion. Not only hamper late EPC activities in vitro, both microRNAs (especially miR-222) also hindered in vivo vasculogenesis in a zebrafish model. Reporter assays showed that miR-222, but not miR-221, targets the angiogenic factor ETS1. In contrast, PIK3R1 is the target of miR-221, but not miR-222 in late EPCs. Clinically, both miR-221-PIK3R1 and miR-222-ETS1 pairs are deregulated in late EPCs of CAD patients.

Conclusions

Our results illustrate EPCs and ECs exploit unique miRNA modalities to regulate angiogenic features, and explain why late EPC levels and activities are reduced in CAD patients. These data will further help to develop new plasma biomarkers and therapeutic approaches for ischemia-related diseases or tumor angiogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-802) contains supplementary material, which is available to authorized users.

Deficiency of the microRNA-31-microRNA-720 pathway in the plasma and endothelial progenitor cells from patients with coronary artery disease

OBJECTIVE

Defects in angiogenesis/vasculogenesis or vessel repair are major complications of coronary artery disease (CAD). Endothelial progenitor cells (EPCs) play a fundamental role in postnatal vascular repair and CAD. The role of microRNAs in CAD pathogenesis and their potential as biomarkers remain to be elucidated.

APPROACH AND RESULTS

MicroRNA-31 (miR-31) level in both the plasma and EPCs of patients with CAD is found lower. miR-31 regulates EPC activities by targeting FAT atypical cadherin 4 and thromboxane A2 receptor, which show increased expression in CAD EPCs. Overexpressing miR-31 in CAD EPCs rescued their angiogenic and vasculogenic abilities both in vitro and in vivo. When exploring approaches to restore endogenous miR-31, we found that far-infrared treatment enhanced the expression of not only miR-31, but also miR-720 in CAD EPCs. miR-720, which was also decreased in EPCs and the plasma of patients with CAD, stimulated EPC activity by targeting vasohibin 1. The miR720-vasohibin 1 pair was shown to be downstream of FAT atypical cadherin 4, but not of thromboxane A2 receptor. FAT atypical cadherin 4 inhibited miR-720 expression via repression of the planar cell polarity signaling gene four-jointed box 1 (FJX1), which was required for miR-720 expression through a hypoxia-inducible factor 1, α subunit-dependent mechanism. Restoring miR-720 level strengthened activity of CAD EPCs. The miR-31-miR-720 pathway is shown critical to EPC activation and that downregulation of this pathway contributes to CAD pathogenesis. Circulating levels of miR-31, miR-720, and vasohibin 1 have the potential to allow early diagnosis of CAD and to act as prognosis biomarkers for CAD and other EPC-related diseases.

CONCLUSIONS

Manipulating the expression of the miR-31-miR-720 pathway in malfunction EPCs should help develop novel therapeutic modalities.

A rare neurological complication due to lithium poisoning

Lithium salts have been used in treatment of depression and bipolar disorder for more than 50 years. Neurotoxic side-effects such as nystagmus, ataxia, tremor, fasciculation, clonus, seizure and even coma have been well described in the literature. We present a case of generalised peripheral neuropathy following lithium intoxication. It is a rare presentation with delayed onset and characterised by a rapid downhill course. Diagnosis was confirmed by nerve conduction tests, which showed axonal neuropathy. Despite the profound neurological effects of this toxicity, it is readily reversible with supportive care and the prognosis is good.

Is it feasible to discuss an advance directive with a Chinese patient with advanced malignancy? A prospective cohort study

OBJECTIVES

Advance directives have been implemented for years in western countries, but the concept is new to Asian cultures. According to traditional Chinese culture, family members usually play a decisive role in a patient's treatment plan. Thus it may be hard to implement an advance directive despite its importance to the treatment of patients. The objectives of this study were to assess the feasibility of advance directive engagement and to explore significant contributing factors to achieving such a goal.

DESIGN

Prospective cohort study.

SETTING

Palliative Care Unit of Clinical Oncology, Tuen Mun Hospital, Hong Kong.

PATIENTS

The subjects of the investigation were adult patients diagnosed to have advanced malignancy and newly referred to the hospice service from 24 April 2009 to 30 July 2009. Data were collected from nursing assessment forms, locally designed advance directive forms, a checklist completed by oncologists, and details available in the electronic hospital record.

RESULTS

Of the 191 eligible patients, 120 (63%) had the advance directive, whereas 71 (37%) did not. In the Cox regression model, the patient having insight of a poor prognosis was the most significant factor facilitating advance directive engagement (P=0.001). Any family objection in the discussion of advance directives was also an important factor, though it did not reach statistical significance (P=0.082). Other factors like age, gender, education, religion, financial status, living environment, understanding the diagnosis, bereavement experience, type of cancer, nature of illness, courses of chemotherapy or radiotherapy received, main caregiver, in-house supporter, nurse-led clinic attendance, clinical psychologist consultation, and in-patient hospice nurse coordinator interview were all statistically insignificant.

CONCLUSIONS

Our study demonstrated that it was feasible to discuss an advance directive with Chinese patients with advanced malignancy. When patients have insight about their poor prognosis and family members have no objection, it may be appropriate to discuss an advance directive.

Human cytomegalovirus preferentially infects the neoplastic epithelium of colorectal cancer: a quantitative and histological analysis

BACKGROUND

It has long been suggested that human cytomegalovirus (HCMV) might be involved in human oncogenesis. However, whether HCMV was associated with colorectal cancer (CRC) was still controversial.

OBJECTIVE

To clarify whether HCMV specifically infects the tumorous tissue of CRC.

STUDY DESIGN

Paired tumor and adjacent non-neoplastic CRC specimens were collected from 163 patients. HCMV DNA was detected and quantified through PCR and quantitative real-time PCR. Virus location was determined by in situ hybridization (ISH) of formalin-fixed paraffin-embedded tissue sections with an HCMV-specific probe.

RESULTS

By PCR, HCMV DNA was detected in 42.3% (69/163) of the tumor specimens, while only 5.6%(14/163) samples of adjacent non-neoplastic tissue were positive for HCMV (p<0.0001). Quantitative real-time PCR in 54 sample pairs revealed significantly higher viral copies in the tumor specimens than the adjacent non-neoplastic tissue specimens (p<0.001). By ISH, the nucleic acids of HCMV were detected in the cytoplasm of neoplastic epithelium. No hybridization was detected in the inflammatory infiltrates, submucosa, or other stromal tissues.

CONCLUSIONS

HCMV preferentially infects the tumor epithelium of CRC. How the virus subsists in and interacts with the microenvironment of tumor epithelium of CRC should be studied.

Interleukin-27 and interleukin-12 augment activation of distinct cord blood natural killer cells responses via STAT3 pathways

BACKGROUND/PURPOSE

Umbilical cord blood is rich in primitive natural killer (NK) cells, which are activated by interleukin (IL)-12. It was previously reported that a novel IL-12 family cytokine, IL-27 comprised of EBI3 and p28, was elevated in maternal serum during normal pregnancy. Thus, we compared the immune regulatory functions of IL-27 and IL-12 on mononuclear cells derived from cord blood and adult peripheral blood.

METHODS

After stimulation with IL-27, IL-12, and IL-27 combined with IL-12, the cytotoxicity against BJAB lymphoma cells by blood mononuclear cells was performed. Then immunofluorescence staining, reverse transcriptase-polymerase chain reaction and Western blotting were used to detect the effects of IL-27 and IL-12 in isolated NK cells.

RESULTS

IL-27, IL-12, and IL-27 combined with IL-12 enhanced the cytotoxicity of adult peripheral blood cells and cord blood cells, but the proliferation of distinct subpopulations of cells was not evident. Similar results were also obtained with purified cord blood NK cells. Interestingly, distinct from IL-12, IL-27 could induce aggregation and morphological changes of umbilical cord blood cells. Finally, IL-27 combined with IL-12 could stimulate increased IL-27 receptor (gp130 and WSX-1) transcripts in purified cord blood NK cells. However, the activation of signal transducer and activator of transcription 3 (STAT3) in NK cells was only detected in the presence of IL-27, but not IL-12 alone.

CONCLUSION

From previous results, we summarize our current understanding of the augmentation of distinct regulation of NK cells by IL-27 and IL-12.

Development of the Chinese version of the Paediatric Allergic Disease Quality of Life Questionnaire: reliability and validity

OBJECTIVE

Paediatric Allergic Disease Quality of Life Questionnaire is a health-related assessment tool designed for children with allergic diseases. This study aimed to translate the original English version of the Questionnaire to Chinese and to provide psychometric evidence on the validity and reliability of the translated version.

DESIGN

Cross-sectional study.

SETTING

Out-patient clinic of a non-teaching hospital in Hong Kong.

PARTICIPANTS

The Paediatric Allergic Disease Quality of Life Questionnaire was translated to Chinese and then completed by a group of 115 Hong Kong Chinese children (66 male and 49 female; mean age, 11 years) with allergic disease(s). All subjects were asked to respond using visual analogue scales dealing with issues related to the perceived morbidity of allergic diseases. To assess test-retest reliability, 2 weeks later a subgroup of 16 individuals was retested with the same Questionnaire.

RESULTS

The internal consistency of the Chinese Paediatric Allergic Disease Quality of Life Questionnaire was satisfactory (Cronbach alpha=0.92). The correlation between the total Questionnaire score and the visual analogue scale score was moderately significant (Spearman's rho=0.49; 95% confidence interval, 0.34-0.62). Structural validity as studied by confirmatory factor analysis found that the structure of subscales was remarkably similar to the original English version. The intra-class correlation between the Questionnaire score from the first and the second test in the subgroup of 16 subjects was 0.75, indicating adequate repeatability.

CONCLUSION

The validity and reliability of the Chinese version of the Paediatric Allergic Disease Quality of Life Questionnaire was established for clinical use.

ATR-FTIR studies on ion interaction of lithium perchlorate in polyacrylate/poly(ethylene oxide) blends

The interaction behaviours between components of polyacrylate (PAc)/poly(ethylene oxide) (PEO) and lithium perchlorate (LiClO(4)) were investigated in detail by Attenuated Total Reflectance (ATR)-Fourier Transformed Infrared (FTIR) spectroscopy. Solution cast films of the PAc/PEO and PAc/PEO/LiClO(4) were examined. No obvious shifting of the characteristic ether and ester group stretching modes of PEO and PAc was observed, indicating incompatibility of the binary PAc/PEO blend. The spectroscopic studies on the PAc/PEO/LiClO(4) blends reveal that Li(+) ions coordinate individually to the polymer components at the ether oxygen of PEO and the C-O of the ester group of PAc. Frequency changes observed on the nu(C-O-C) and omega(CH(2)) of PEO confirm the coordination between PEO and Li(+) ions resulting in crystallinity suppression of PEO. The absence of experimental evidence on the formation of PEO-Li(+)-PAc complexes suggests that LiClO(4) does not enhance the compatibility of PAc/PEO blend.

Clinical Predictors of Minor Head Injury Patients Presenting with Glasgow Coma Scale Score of 14 or 15 and Requiring Neurosurgical Intervention

Introduction

Minor head injury is the most common type of head injury assessed in accident and emergency departments. Emergency physicians have concerns in discharging patients with intracranial injuries which require neurosurgical interventions. The aim of this study is to find out the clinical signs and symptoms which can help to predict who need neurosurgical intervention following minor head injury.

Methods

This was a retrospective case-control study. Patients with head injury and GCS score of 14 or 15 and requiring neurosurgical intervention were recruited. Another group of patients with head injury and GCS score of 14 or 15 but not requiring neurosurgical intervention were enrolled as control. In all cases, clinical signs and symptoms were collected by chart review of the clinical records retrieved by the computerized Clinical Data Analysis & Reporting System (CDARS). The relationship between clinical features and need of neurosurgical intervention was analyzed by chi-square test with 95% confidence interval.

Results

A total of 22 cases were found and compared with 288 controls to study on the clinical variables for the prediction of the need of neurosurgical intervention. Six warning signs were found statistically significant by univariate analysis: severe headache (p=0.0206), vomiting more than once (p<0.0006), drop in GCS (p<0.0001), confusion/restlessness (p<0.0001), bleeding from ear (p<0.0001) and skull fracture in the X-ray (p<0.0001).

Conclusion

Patients with minor head injury presenting with GCS score of 14 or 15 to the accident and emergency department rarely require neurosurgical intervention. Some clinical risk factors can be used as a guide to identify those who need neurosurgical intervention following minor head injury.

Tumor necrosis factor alpha promoter polymorphism and the risk of chronic lymphocytic leukemia and myeloma in the Chinese population

The -308 GA promoter polymorphism of tumor necrosis factor alpha (TNFalpha) has been reported to be associated with an increased risk of lymphoid malignancies in Caucasians. We studied the incidence and prognostic significance of this polymorphism in Chinese patients with plasma cell myeloma (PCM), chronic lymphocytic leukemia (CLL) and lymphomas. Despite a far lower incidence of PCM and CLL in the Chinese population compared with Caucasians, the rates of TNFalpha-308A were similar to those in Caucasians, both in the study and control populations. Similarly, there was no increased rate of TNFalpha-308A in all the lymphomas studied, irrespective of lineage. However, TNFalpha-308A is significantly associated with female CLL cases and confers a strong negative prognostic impact for Chinese CLL. These argue for a possible biological role for increased TNFalpha production in CLL progression in low-risk individuals.

Cryoglobulinaemia: clinical and laboratory perspectives

Cryoglobulins are immunoglobulins that precipitate in the serum upon cooling to below core body temperature and re-dissolve at higher temperatures. Cryoglobulinaemia may be life-threatening. The three types of cryoglobulinaemia are associated with a wide spectrum of haematological, autoimmune, and chronic infectious diseases, especially hepatitis C infection. Our laboratory has received 378 requests for cryoglobulin testing over the past 5 years, with a detection rate of 4.8% in the 271 patients involved. Twelve per cent of the specimens were not processed due to being at an inappropriate temperature on arrival at the laboratory. Clinicians should be aware of temperature requirements when requesting cryoglobulin testing in suspected cases, and for all relevant protein tests in patients with cryoglobulinaemia. Handling specimens at inappropriate temperatures in the pre-analytical and analytical phases of the investigation might lead to cryoprecipitation and therefore false-negative results. The potential pitfalls encountered with specimen handling, analysis, and result interpretation are discussed in detail.

Survey of Salmonella contamination of raw shell eggs used in food service premises in the United Kingdom, 2005 through 2006

This survey was launched after an unusual number of Salmonella Enteritidis outbreaks associated with the use of eggs in food service premises in England and Wales. Between November 2005 and December 2006, 9,528 eggs (1,588 pooled samples of 6 eggs) were collected from 1,567 food service premises in the United Kingdom, most of which (89%) were produced in the United Kingdom. Salmonella was isolated from 6 (0.38%) pools of eggs. Of these, 5 (0.31%) were Salmonella Enteritidis, which were further characterized to phage types (PTs): PT 4 (0.19%), PT 8 (0.06%), and PT 12 (0.06%). Salmonella Mbandaka was also isolated (0.06%). Salmonella was detected from five and one of pooled eggs samples that were produced in the United Kingdom and Germany, respectively; these were from different producers. The study showed evidence of poor egg storage and handling practices in food service premises, in that 55% did not store eggs under refrigerated conditions; 20.7% of eggs had expired "best before" dates or were in use after 3 weeks of lay, indicating poor stock rotation; and 37.1% pooled eggs not intended for immediate service. Eggs are a commonly consumed food that may occasionally be contaminated with Salmonella at different rates, according to their country of origin. The food service sector needs to be aware of this continuing hazard, receive appropriate food safety and hygiene training on storage and usage of raw shell eggs, adopt appropriate control measures, and follow advice provided by national food agencies in order to reduce the risk of infection.

Survey of Salmonella contamination of non-United Kingdom-produced raw shell eggs on retail sale in the northwest of England and London, 2005 to 2006

This survey was prompted by a change in the epidemiology of Salmonella Enteritidis infections in England and Wales and elsewhere in Europe and, to our knowledge, is the first survey to provide information on Salmonella contamination of non-United Kingdom eggs on retail sale. Based on 10,464 non-United Kingdom eggs (1744 pooled samples of six eggs) purchased between March 2005 and July 2006, the total weighted prevalence estimate for all Salmonella detected in non-United Kingdom eggs was 3.3%. Of the eggs sampled, most were produced in Spain (66.3%), France (20.0%), or The Netherlands (7.4%). Salmonella was detected from 4.4 and 0.3% of eggs produced in Spain and France, respectively, with weighted prevalence estimates. Eight different Salmonella serotypes were recovered from non-United Kingdom eggs, of which Salmonella Enteritidis predominated, with an estimated prevalence of 2.6%. Salmonella Enteritidis was obtained only from Spanish eggs. Nine different phage types of Salmonella Enteritidis were identified, with phage type 1 found to be the predominant phage type. Most of the Salmonella Enteritidis isolates obtained from Spanish eggs in the survey were resistant to nalidixic acid with concomitant decreased susceptibility to ciprofloxacin (0.125 to 1.0 mg/liter) or ampicillin (8.0 mg/liter). Salmonella Enteritidis phage type 1 until now had not been detected in eggs examined as part of previous United Kingdom egg surveys but has been detected in eggs of Spanish origin examined during recent national outbreaks of Salmonella Enteritidis non-phage type 4 infections in England and Wales. Eggs are a commonly consumed food that may occasionally be contaminated with Salmonella. The rates of contamination may be linked to the origin of the eggs. Consumers and caterers need to be aware of this continuing hazard, adopt appropriate control measures, and follow advice provided by national food agencies in order to reduce the risk of infection.

Temperature dependence of surface photovoltage spectroscopy in vertically coupled self-organized InAs/GaAs quantum dots

The surface photovoltage (SPV) spectra of a series of vertically stacked self-organized InAs/GaAs quantum dot (QD)-based laser structures with different spacer layer (SL) thickness were obtained as a function of temperature (77 K </= T </= 300 K). A decrease of the compressive stress for thinner SL samples arising from coherent relaxation enables us to designate the effect of material intermixing as the most probable mechanism of the energetic blueshift of the observed structures. The turnaround characteristic of the temperature-dependent spectral intensity shows that the reduced SPV signal at higher temperature is limited by the carrier scattering and at lower temperature it is governed by the magnitude of built-in electric field and the escape efficiency of the photogenerated carriers. The dot states to be blueshifted by material intermixing are expected to have higher escape rate for carriers out of QDs, thus resulting in lower measurable temperature for the detected SPV signal. The relatively higher signal at low temperature for the 10 nm SL sample provides a direct evidence of the tunneling process of carriers in the stacked QD layers.

Runoff characteristics and application of HEC-HMS for modelling stormflow hydrograph in an oil palm catchment

Rainfall-runoff processes in a small oil palm catchment (8.2 ha) in Johor, Malaysia were examined. Storm hydrographs show rapid responses to rainfall with a short time to peak. The estimated initial hydrologic loss for the oil palm catchment is 5 mm. Despite the low initial loss, the catchment exhibits a high proportion of baseflow, approximately 54% of the total runoff. On an event basis, the stormflow response factor and runoff coefficient ranges from 0.003 to 0.21, and 0.02 to 0.44, respectively. Peakflow and stormflow volume were moderately correlated with rainfall. The hydrographs were satisfactorily modelled using the Hydrologic Engineering Centre-Hydrologic Modelling System (HEC-HMS). The efficiency indexes of the calibration and validation exercises are 0.81 and 0.82, respectively. Based on these preliminary findings, it could be suggested that an oil palm plantation would be able to serve reasonably well in regulating basic hydrological functions.

Dose-by-dose virological and hematological responses to intravenous immunoglobulin in an immunocompromised patient with persistent parvovirus B19 infection

A 42-year-old male with stage IV mantle cell lymphoma received chemotherapy and autologous peripheral blood stem cell transplantation. He developed pancytopaenia, and bone marrow examination indicated a parvovirus B19 (PVB 19)-induced red cell aplasia, confirmed by virological tests. Multiple doses of intravenous immunoglobulin (IVIG) were given over the following months, with blood samples being taken after each dose for quantitative PVB 19 DNA and hematological testing to assess the response. Each dose of IVIG produced a 1-3 log(10) drop in PVB 19 DNA levels. Eventually, after the fifth dose of IVIG, the PVB 19 DNA was reduced to <10 copies/ml serum, with a gradual improvement in his hematological parameters. This report demonstrates how close monitoring of the virological and hematological response to IVIG therapy for persistent PVB 19 infection in an immunocompromised patient can optimize the usage of this relatively expensive, and sometimes scarce intervention.

Application of artificial neural networks to establish a predictive mortality risk model in children admitted to a paediatric intensive care unit

INTRODUCTION

Paediatric risk of mortality and paediatric index of mortality (PIM) are the commonly-used mortality prediction models (MPM) in children admitted to paediatric intensive care unit (PICU). The current study was undertaken to develop a better MPM using artificial neural network, a domain of artificial intelligence.

METHODS

The purpose of this retrospective case series was to compare an artificial neural network (ANN) model and PIM with the observed mortality in a cohort of patients admitted to a five-bed PICU in a Hong Kong non-teaching general hospital. The patients were under the age of 17 years and admitted to our PICU from April 2001 to December 2004. Data were collected from each patient admitted to our PICU. All data were randomly allocated to either the training or validation set. The data from the training set were used to construct a series of ANN models. The data from the validation set were used to validate the ANN and PIM models. The accuracy of ANN models and PIM was assessed by area under the receiver operator characteristics (ROC) curve and calibration.

RESULTS

All data were randomly allocated to either the training (n=274) or validation set (n=273). Three ANN models were developed using the data from the training set, namely ANN8 (trained with variables required for PIM), ANN9 (trained with variables required for PIM and pre-ICU intubation) and ANN23 (trained with variables required for ANN9 and 14 principal ICU diagnoses). Three ANN models and PIM were used to predict mortality in the validation set. We found that PIM and ANN9 had a high ROC curve (PIM: 0.808, 95 percent confidence interval 0.552 to 1.000, ANN9: 0.957, 95 percent confidence interval 0.915 to 1.000), whereas ANN8 and ANN23 gave a suboptimal area under the ROC curve. ANN8 required only five variables for the calculation of risk, compared with eight for PIM.

CONCLUSION

The current study demonstrated the process of predictive mortality risk model development using ANN. Further multicentre studies are required to produce a representative ANN-based mortality prediction model for use in different PICUs.

Obstructive sleep apnoea in children with Down syndrome

INTRODUCTION

Children with Down syndrome (DS) are prone to develop obstructive sleep apnoea (OSA) for a combination of reasons, including small upper airway, midfacial hypoplasia, micrognathia and muscular hypotonia. The objective of this study was to compare the prevalence of OSA in DS children, with or without snoring, with snoring children matched for gender, age and weight for height.

METHODS

DS children were prospectively recruited from the Hong Kong Down Syndrome Association. All recruited DS children underwent a sleep polysomnography (PSG) in our sleep laboratory. The same number of patients without DS who underwent sleep PSG in the same period were enrolled as controls after they were matched for gender, age and weight for height. OSA was defined as apnoea-hypopnoea index (AHI) greater than 1.5.

RESULTS

22 DS patients and 22 snoring controls completed the overnight PSG. The mean age of DS children and snoring controls was 10.82 +/- 5.93 and 10.27 +/- 5.68 years, respectively. The prevalence of OSA was 59 percent in DS children and 32 percent in snoring controls. Median and interquartile range (IQR) of AHI of DS children (median 1.80, IQR is 0.40 to 7.10) were significantly higher than those of controls (median 0.50, IQR is 0.00 to 2.03, p-value equals 0.041). Out of 13 DS children with OSA, eight of them (61.5 percent) had no habitual snoring.

CONCLUSION

59 percent of DS children in the current series were found to have OSA and they were more likely to develop OSA than controls. Nearly 40 percent of DS children with OSA did not have habitual snoring.

Efficient calculation of electron diffraction for the structural determination of nanomaterials

A critical advance in the technique of low-energy electron diffraction is presented and shown to enable determining detailed structures of nanomaterials, based on experimental methods that already exist or have been proposed. Our new cluster approach speeds up the computation to scale as n logn, rather than the current n3 or n2, with n the number of atoms, for example. Applications are illustrated for C60 molecules adsorbed on a Cu(111) surface, with and without coadsorbed metal atoms, exhibiting sensitivity to important structural features such as buckyball size and deformation.