321 research outputs found
Detection of Trypanosoma brucei gambiense and T. b. rhodesiense in Glossina fuscipes fuscipes (Diptera: Glossinidae) and Stomoxys flies using the polymerase chain reaction (PCR) technique in southern Sudan
Ethanol-fixed entire bodies of the tsetse fly, Glossina fuscipes fuscipes, and unidentified stable flies, Stomoxys spp., collected from near Juba town, southern Sudan, were tested for Trypanozoon trypanosomes infections using polymerase chain reaction (PCR) technique for the first time in Sudan. The crude target DNA sequences were extracted by incubation of entire flies in Nonindet PCR template buffer containing proteinase-K. The DNA amplification sets of conditions were adjusted for each pair of primers employed. The oligonucleotide primers used included TBR1-2, SRAA-E, SRAB537-B538 and TgsGPFOR-REV. The results showed that 74.4% of G. f. fuscipes and 39.36% of Stomoxys spp. were infected with Trypanozoon trypanosomes. Out of the 117 examined G. f. fuscipes, 46.2, 24.8, 35.04, 17.09 and 10.26% were due to T. b. gambiense (TgsGPFOR-REV), T. b. rhodesiense (SRAA-E), T. b. rhodesiense (SRA3537-3538), mixed infection with T. b. gambiense and T. b. rhodesiense and T. b. brucei, respectively. However, infections in Stomoxys spp. of 2.13 and 37.2% were due to T. b. rhodesiense and T. b. brucei, respectively.Key words: Glossina fuscipes fuscipes, T. b. gambiense, T. b. Rhodesiense, vectoral capacity, infection rate, PCR technology
Co-sensitization effect of N719 dye with Cu doped CdS colloidal nanoparticles for dye sensitized solar cells
This is the final version. Available on open access from Elsevier via the DOI in this recordData availability:
Data will be made available on request.Dye-sensitized solar cell’s (DSSC) performances are enhanced by engineering the materials at the interface of various device components owing to easy and inexpensive fabrication steps. Ru (II) polypyridyl-based synthetic dyes are the most widely used photosensitizers for DSSCs due to their superior molar extinction coefficient and facile interaction with metal oxide electrodes. However, these dyes are mostly expensive, and as a result, natural dyes and metal-free organic dyes have become an alternative way for sensitization to reduce the significant drawbacks of synthetic dyes. In this study, minimizing the usage of the N719 dye can be performed through an alternative method for better light-harvesting through supreme optical interfacial interaction with colloidal Cu-doped CdS as a co-sensitizer in a facile approach. This co-sensitization signifies the colloidal CdS (donor), which can corroborate the energy transfer mechanism with the N719 dye (acceptor). The introduction of Cu causes extreme tuning of broad absorption to near-infrared for CdS, enhancing the solar light harvesting entrapment followed by extensive optical interaction with N719 dye. This accelerates the activity of the sensitizers for light absorption enhancement and expects a better performance of DSSC compared to traditional sensitization. A massive improvement in photocurrent density (∼42 %) was observed without sacrificing other photovoltaic parameters, as observed for TiO2-based photoanodes. The sensitizer’s interfacial optical energy transfer process, unless excited electron recombination, may indirectly be used as an excitation source of the acceptor and minimizes the recombination energy loss.Engineering and Physical Sciences Research Council (EPSRC)British Counci
Metastatic collecting duct carcinoma of the kidney treated with sunitinib
Collecting duct carcinoma (CDC) of the kidney is a rare and aggressive malignant tumor arising from the distal collecting tubules which has been shown to have a poor response to several kinds of systemic therapy. We present a case of metastatic CDC that responded favorably to a multiple tyrosine kinase inhibitor, sunitinib, achieving a partial response in both lung and skeletal metastases. To our knowledge, this is the first report showing therapeutic activity of sunitinib against CDC. Considering these findings, it would be worthwhile prospectively investigating the role of multiple tyrosine kinase inhibitors, particularly sunitinib, in the management of metastatic CDC
Interval estimation and optimal design for the within-subject coefficient of variation for continuous and binary variables
BACKGROUND: In this paper we propose the use of the within-subject coefficient of variation as an index of a measurement's reliability. For continuous variables and based on its maximum likelihood estimation we derive a variance-stabilizing transformation and discuss confidence interval construction within the framework of a one-way random effects model. We investigate sample size requirements for the within-subject coefficient of variation for continuous and binary variables. METHODS: We investigate the validity of the approximate normal confidence interval by Monte Carlo simulations. In designing a reliability study, a crucial issue is the balance between the number of subjects to be recruited and the number of repeated measurements per subject. We discuss efficiency of estimation and cost considerations for the optimal allocation of the sample resources. The approach is illustrated by an example on Magnetic Resonance Imaging (MRI). We also discuss the issue of sample size estimation for dichotomous responses with two examples. RESULTS: For the continuous variable we found that the variance stabilizing transformation improves the asymptotic coverage probabilities on the within-subject coefficient of variation for the continuous variable. The maximum like estimation and sample size estimation based on pre-specified width of confidence interval are novel contribution to the literature for the binary variable. CONCLUSION: Using the sample size formulas, we hope to help clinical epidemiologists and practicing statisticians to efficiently design reliability studies using the within-subject coefficient of variation, whether the variable of interest is continuous or binary
An autosomal recessive leucoencephalopathy with ischemic stroke, dysmorphic syndrome and retinitis pigmentosa maps to chromosome 17q24.2-25.3
Background
Single-gene disorders related to ischemic stroke seem to be an important cause of stroke in young patients without known risk factors. To identify new genes responsible of such diseases, we studied a consanguineous Moroccan family with three affected individuals displaying hereditary leucoencephalopathy with ischemic stroke, dysmorphic syndrome and retinitis pigmentosa that appears to segregate in autosomal recessive pattern.
Methods
All family members underwent neurological and radiological examinations. A genome wide search was conducted in this family using the ABI PRISM linkage mapping set version 2.5 from Applied Biosystems. Six candidate genes within the region linked to the disease were screened for mutations by direct sequencing.
Results
Evidence of linkage was obtained on chromosome 17q24.2-25.3. Analysis of recombination events and LOD score calculation suggests linkage of the responsible gene in a genetic interval of 11 Mb located between D17S789 and D17S1806 with a maximal multipoint LOD score of 2.90. Sequencing of seven candidate genes in this locus, ATP5H, FDXR, SLC25A19, MCT8, CYGB, KCNJ16 and GRIN2C, identified three missense mutations in the FDXR gene which were also found in a homozygous state in three healthy controls, suggesting that these variants are not disease-causing mutations in the family.
Conclusion
A novel locus for leucoencephalopathy with ischemic stroke, dysmorphic syndrome and retinitis pigmentosa has been mapped to chromosome 17q24.2-25.3 in a consanguineous Moroccan family
Fructose-1, 6-diphosphate (FDP) as a novel antidote for yellow oleander-induced cardiac toxicity: A randomized controlled double blind study
BACKGROUND: Cardiac toxicity due to ingestion of oleander plant seeds in Sri Lanka and some other South Asian countries is very common. At present symptomatic oleander seed poisoning carries a mortality of 10% in Sri Lanka and treatment of yellow oleander poisoning is limited to gastric decontamination and atropine administration. The only proven effective antidote is digoxin antibodies but these are not available for routine use because of the high cost. The main objective of this study is to investigate the effectiveness of a new and inexpensive antidote for patients with life threatening arrhythmias due oleander poisoning. METHOD/DESIGN: We set up a randomised double blind clinical trial to assess the effectiveness of Fructose 1, 6 diphosphate (FDP) in acute yellow oleander poisoning patients admitted to the adult medical wards of a tertiary hospital in Sri Lanka. Patients will be initially resuscitated following the national guidelines and eligible patients will be randomised to receive either FDP or an equal amount of normal saline. The primary outcome measure for this study is the sustained reversion to sinus rhythm with a heart rate greater than 50/min within 2 hours of completion of FDP/placebo bolus. Secondary outcomes include death, reversal of hyperkalaemia on the 6, 12, 18 and 24 hour samples and maintenance of sinus rhythm on the holter monitor. Analysis will be on intention-to-treat. DISCUSSION: This trial will provide information on the effectiveness of FDP in yellow oleander poisoning. If FDP is effective in cardiac glycoside toxicity, it would provide substantial benefit to the patients in rural Asia. The drug is inexpensive and thus could be made available at primary care hospitals if proven to be effective. TRIAL REGISTRATION: Current Controlled trial ISRCTN71018309
The Role of Histone Methylation and H2A.Z Occupancy during Rapid Activation of Ethylene Responsive Genes
Ethylene signaling pathway leads to rapid gene activation by two hierarchies of transcription factors with EIN3/EIL proteins as primary ones and ERF proteins as secondary ones. The role of chromatin modifications during the rapid gene activation is not known. In this work we studied trimethylated histone H3 lysine 4 (H3K4me3) and lysine 27 (H3K27me3), two opposite histone methylation marks for gene activity, during the induction course of three ethylene-responsive genes (ERF1, AtERF14 and ChiB). We found that the three genes displayed different histone modification profiles before induction. After induction, H3K4me3 was increased in the 5′ region and the gene body of ERF1, while H3K27me3 was decreased in the promoter of AtERF14. But the modification changes were later than the gene activation. Analysis of other rapidly inducible ERF genes confirmed the observation. In addition, histone H2A.Z occupancy on the three genes and the association of the H3K27me3-binding protein LHP1 with AtERF14 and ChiB were not affected by the inductive signal. However, the mutation of genes encoding H2A.Z and LHP1 attenuated and enhanced respectively the induction of target genes and altered H3K4me3. These results indicate that the induction of ethylene-responsive genes does not require immediate modulation of H3K4me3 and H3K27me3 and dissociation of LHP1 and H2A.Z from the targets, and suggest that the chromatin structure of the genes before induction is committed for transcriptional activation and that H3K4me3 is not required for ethylene-responsive gene activation, but may serve as a mark for gene activity
Utilisation of an operative difficulty grading scale for laparoscopic cholecystectomy
Background
A reliable system for grading operative difficulty of laparoscopic cholecystectomy would standardise description of findings and reporting of outcomes. The aim of this study was to validate a difficulty grading system (Nassar scale), testing its applicability and consistency in two large prospective datasets.
Methods
Patient and disease-related variables and 30-day outcomes were identified in two prospective cholecystectomy databases: the multi-centre prospective cohort of 8820 patients from the recent CholeS Study and the single-surgeon series containing 4089 patients. Operative data and patient outcomes were correlated with Nassar operative difficultly scale, using Kendall’s tau for dichotomous variables, or Jonckheere–Terpstra tests for continuous variables. A ROC curve analysis was performed, to quantify the predictive accuracy of the scale for each outcome, with continuous outcomes dichotomised, prior to analysis.
Results
A higher operative difficulty grade was consistently associated with worse outcomes for the patients in both the reference and CholeS cohorts. The median length of stay increased from 0 to 4 days, and the 30-day complication rate from 7.6 to 24.4% as the difficulty grade increased from 1 to 4/5 (both p < 0.001). In the CholeS cohort, a higher difficulty grade was found to be most strongly associated with conversion to open and 30-day mortality (AUROC = 0.903, 0.822, respectively). On multivariable analysis, the Nassar operative difficultly scale was found to be a significant independent predictor of operative duration, conversion to open surgery, 30-day complications and 30-day reintervention (all p < 0.001).
Conclusion
We have shown that an operative difficulty scale can standardise the description of operative findings by multiple grades of surgeons to facilitate audit, training assessment and research. It provides a tool for reporting operative findings, disease severity and technical difficulty and can be utilised in future research to reliably compare outcomes according to case mix and intra-operative difficulty
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