150 research outputs found
Effect of the lipase inhibitor orlistat and of dietary lipid on the absorption of radiolabelled triolein, tri-γ-linolenin and tripalmitin in mice
Orlistat, a selective inhibitor of gastrointestinal lipases, was used to investigate triacylglycerol absorption. Using mice and a variety of emulsified dietary lipids we found that the absorption of radiolabelled tripalmitin (containing the fatty acid 16:0), but not of triolein (18: 1n−9) or tri-γ-linolenin (18:3n−6), was incomplete from meals rich in esterified palmitate. Further, the absorption of radiolabelled tri-γ-linolenin, from both saturated and unsaturated dietary triacylglycerols, was 1·3- to 2-fold more potently inhibited by orlistat than that of triolein and tripalmitin. These radiolabelled triacylglycerols, which have the same fatty acid in all three positions, may not always be accurate markers of the absorption of dietary triacylglycerols. Orlistat was more effective at inhibiting the absorption of radiolabelled triacylglycerols with which it was codissolved than those added separately, which indicates that equilibration between lipid phases in the stomach may not always be complete. The saturation of the dietary lipid had little or no effect on the potency of orlistat. Orlistat provides a novel approach for studying the role of triacylglycerol hydrolysis in the overall process of triacylglycerol absorptio
The Viking seismometry
Efforts were made to determine the seismicity of Mars as well as define its internal structure by detecting vibrations generated by marsquakes and meteoroid impacts. The lack of marsquakes recognized in the Viking data made it impossible to make any direct inferences about the interior of Mars and only allowed the setting of upper bounds on the seismic activity of the planet. After obtaining more than 2100 hours worth of data during the quite periods at rates of one sample per second or higher, the Viking 2 seismometer was turned off as a consequence of a landing system failure. During the periods when adequate data were obtained, one event of possible seismic or meteoroid impact origin was recognized; however, there is a significant probability that this event was generated by a wind gust
Predicting outcome in childhood diffuse midline gliomas using magnetic resonance imaging based texture analysis
BACKGROUND: Diffuse midline gliomas (DMG) are aggressive brain tumours, previously known as diffuse intrinsic pontine gliomas (DIPG), with 10% overall survival (OS) at 18 months. Predicting OS will help refine treatment strategy in this patient group. MRI based texture analysis (MRTA) is novel image analysis technique that provides objective information about spatial arrangement of MRI signal intensity (heterogeneity) and has potential to be imaging biomarker.
OBJECTIVES: To investigate MRTA in predicting OS in childhood DMG.
METHODS: Retrospective study of patients diagnosed with DMG, based on radiological features, treated at our institution 2007-2017. MRIs were acquired at diagnosis and 6 weeks after radiotherapy (54Gy in 30 fractions). MRTA was performed using commercial available TexRAD research software on T2W sequence and Apparent Diffusion Coefficient (ADC) maps encapsulating tumour in the largest single axial plane. MRTA comprised filtration-histogram technique using statistical and histogram metrics for quantification of texture. Kaplan-Meier survival analysis determined association of MRI texture parameters with OS.
RESULTS: 32 children 2-14 years (median 7 years) were included. MRTA was undertaken on T2W (n=32) and ADC (n=22). T2W-MRTA parameters were better at prognosticating than ADC-MRTA. Children with homogenous tumour texture, at medium scale on diagnostic T2W MRI, had worse prognosis (Mean of Positive Pixels (MPP): p=0.005, mean: p=0.009, SD: p=0.011, kurtosis: p=0.037, entropy: p=0.042). Best predictor MPP was able to stratify patients into poor and good prognostic groups with median survival of 7.5 months versus 17.5 months, respectively.
CONCLUSIONS: DMG with more homogeneous texture on diagnostic MRI is associated with worse prognosis. Texture parameter MPP is the most predictive marker of OS in childhood DMG
Immunohistochemical evaluation of molecular radiotherapy target expression in neuroblastoma tissue
Purpose
Neuroblastoma may be treated with molecular radiotherapy, 131I meta-Iodobenzylguanidine and 177Lu Lutetium DOTATATE, directed at distinct molecular targets: Noradrenaline Transporter Molecule (NAT) and Somatostatin Receptor (SSTR2), respectively. This study used immunohistochemistry to evaluate target expression in archival neuroblastoma tissue, to determine whether it might facilitate clinical use of molecular radiotherapy.
Methods
Tissue bank samples of formalin fixed paraffin embedded neuroblastoma tissue from patients for whom clinical outcome data were available were sectioned and stained with haematoxylin and eosin, and monoclonal antibodies directed against NAT and SSTR2. Sections were examined blinded to clinical information and scored for the percentage and intensity of tumour cells stained. These data were analysed in conjunction with clinical data.
Results
Tissue from 75 patients was examined. Target expression scores varied widely between patients: NAT median 45%, inter-quartile range 25% - 65%; and SSTR2 median 55%, interquartile range 30% – 80%; and in some cases heterogeneity of expression between different parts of a tumour was observed. A weak positive correlation was observed between the expression scores of the different targets: correlation coefficient = 0.23, p = 0.05. MYCN amplified tumours had lower SSTR2 scores: mean difference 23% confidence interval 8% - 39%, p < 0.01. Survival did not differ by scores.
Conclusions
As expression of both targets is variable and heterogeneous, imaging assessment of both may yield more clinical information than either alone. The clinical value of immunohistochemical assessment of target expression requires prospective evaluation. Variable target expression within a patient may contribute to treatment failure
Spectrum of neuroimaging findings post-proton beam therapy in a large pediatric cohort
PURPOSE: Proton beam therapy (PBT) is now well established for the treatment of certain pediatric brain tumors. The intrinsic properties of PBT are known to reduce long-term negative effects of photon radiotherapy (PRT). To better understand the intracranial effects of PBT, we analyzed the longitudinal imaging changes in a cohort of children with brain tumors treated by PBT with clinical and radiotherapy dose correlations. MATERIALS AND METHODS: Retrospective imaging review of 46 patients from our hospital with brain tumors treated by PBT. The imaging findings were correlated with clinical and dose parameters. RESULTS: Imaging changes were assessed by reviewing serial magnetic resonance imaging (MRI) scans following PBT over a follow-up period ranging from 1 month to 7 years. Imaging changes were observed in 23 patients undergoing PBT and categorized as pseudoprogression (10 patients, 43%), white matter changes (6 patients, 23%), parenchymal atrophy (6 patients, 23%), and cerebral large vessel arteriopathy (5 patients, 25%). Three patients had more than one type of imaging change. Clinical symptoms attributable to PBT were observed in 13 (28%) patients. CONCLUSION: In accordance with published literature, we found evidence of varied intracranial imaging changes in pediatric brain tumor patients treated with PBT. There was a higher incidence (10%) of large vessel cerebral arteriopathy in our cohort than previously described in the literature. Twenty-eight percent of patients had clinical sequelae as a result of these changes, particularly in the large vessel arteriopathy subgroup, arguing the need for angiographic and perfusion surveillance to pre-empt any morbidities and offer potential neuro-protection
Parents' responses to prognostic disclosure at diagnosis of a child with a high‐risk brain tumor: Analysis of clinician‐parent interactions and implications for clinical practice
Background: Previous studies have found that parents of children with cancer desire more prognostic information than is often given even when prognosis is poor. We explored in audio‐recorded consultations the kinds of information they seek. /
Methods: Ethnographic study including observation and audio recording of consultations at diagnosis. Consultations were transcribed and analyzed using an interactionist perspective including tools drawn from conversation and discourse analysis. /
Results: Enrolled 21 parents and 12 clinicians in 13 cases of children diagnosed with a high‐risk brain tumor (HRBT) over 20 months at a tertiary pediatric oncology center. Clinicians presented prognostic information in all cases. Through their questions, parents revealed what further information they desired. Clinicians made clear that no one could be absolutely certain what the future held for an individual child. Explicit communication about prognosis did not satisfy parents’ desire for information about their own child. Parents tried to personalize prognostic information and to apply it to their own situation. Parents moved beyond prognostic information presented and drew conclusions, which could change over time. Parents who were present in the same consultations could form different views of their child's prognosis. /
Conclusion: Population level prognostic information left parents uncertain about their child's future. The need parents revealed was not for more such information but rather how to use the information given and how to apply it to their child in the face of such uncertainty. Further research is needed on how best to help parents deal with uncertainty and make prognostic information actionable
Radiation Reveal: Moving from research engagement to involvement.
Here, we report on the process of a highly impactful and successful creative, collaborative, and multi-partner public engagement project, Radiation Reveal. It brought together ten young adults aged 17-25-year-olds with experience of radiotherapy with researchers at Cancer Research UK RadNet City of London across three 2-hour online workshops. Our aims were to 1) initiate discussions between young adults and radiation researchers, and 2) identify what people wish they had known about radiotherapy before or during treatment. These aims were surpassed; other benefits included peer support, participants' continued involvement in subsequent engagement projects, lasting friendships, creation of support groups for others, and creation and national dissemination of top ten tips for medical professionals and social media resources. A key learning was that this project required a dedicated and (com)passionate person with connections to national cancer charities. When designing the project, constant feedback is also needed from charities and young adults with and without radiotherapy experience. Finally, visually capturing discussions and keeping the door open beyond workshops further enhanced impact. Here, we hope to inform and inspire people to help project the patient voice in all we do
Identification of novel bacteriophages with therapeutic potential targeting Enterococcus faecalis
The Gram-positive opportunistic pathogen Enterococcus faecalis is frequently responsible for nosocomial infections in humans and represents one of the most common bacteria isolated from recalcitrant endodontic (root canal) infections. E. faecalis is intrinsically resistant to several antibiotics routinely used in clinical settings (such as cephalosporins and aminoglycosides) and can acquire resistance to vancomycin (vancomycin resistant enterococci, VRE). The resistance of E. faecalis to several classes of antibiotics and its capacity to form biofilms cause serious therapeutic problems. In this paper, we report the isolation of several bacteriophages that target E. faecalis strains isolated from the oral cavity of patients suffering root-canal infections. All phages isolated were Siphoviridae with similar tail lengths (200-250 nm) and icosahedral heads. The genome sequences of three isolated phages were highly conserved with the exception of predicted tail protein genes that diverge in sequence, potentially reflecting host range. The properties of the phage with the broadest host-range (SHEF2), was further characterised. We showed that this phage requires interaction with components of the major and variant region Enterococcal polysaccharide antigen (Epa) to engage in lytic infection. Finally, we explored the therapeutic potential of this phage and showed that it can eradicate E. faecalis biofilms formed in vitro on a standard polystyrene surface but also on a cross-sectional tooth-slice model of endodontic infection. We also show that SHEF2 cleared a lethal infection of zebrafish when applied in the circulation. We therefore propose that the phage described in this study could be used to treat a broad range of antibiotic resistant E. faecalis infections
Co-ordination of local policies for urban development and public transportation in four Swiss cities
The present article aims at assessing the possibility for urban areas to coordinate local policies of urban development and public transportation and at explaining the differences in this achievement between urban regions. In order to do so, the study draws support from two empirical sources: a historical analysis of the "mass-production" generated by the public service sectors in the field of transport and urban development in the cities of Basel, Bern, Geneva, and Lausanne since 1950, and a series of six case studies in these four cities. The study identifies factors located both at context level regarding morphological and geographical conditions as well as institutional settings and case-specific idiosyncrasies regarding organizational structure, past policy decisions, as well as vocational cultures that determine the possibility for urban areas to meet the need for policy coordination
Nowhere to go: How stigma limits the options of female drug users after release from jail
<p>Abstract</p> <p>Background</p> <p>Drug and alcohol using women leaving prison or jail face many challenges to successful re-integration in the community and are severely hampered in their efforts by the stigma of drug or alcohol use compounded by the stigma of incarceration.</p> <p>Methods</p> <p>This qualitative study is based on individual semi-structured interviews and focus groups with 17 women who had recently left jail about the challenges they faced on reentry.</p> <p>Results</p> <p>Our analysis identified three major themes, which are related by the overarching influence of stigma: survival (jobs and housing), access to treatment services, and family and community reintegration.</p> <p>Conclusion</p> <p>Stigma based on drug use and incarceration works to increase the needs of women for health and social services and at the same time, restricts their access to these services. These specific forms of stigma may amplify gender and race-based stigma. Punitive drug and social policies related to employment, housing, education, welfare, and mental health and substance abuse treatment make it extremely difficult for women to succeed.</p
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