Report of AAPM Therapy Physics Committee Task Group 74: Inâ air output ratio, Sc, for megavoltage photon beams

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134830/1/mp7367.pd

Identification of novel subgroup a variants with enhanced receptor binding and replicative capacity in primary isolates of anaemogenic strains of feline leukaemia virus

<b>BACKGROUND:</b> The development of anaemia in feline leukaemia virus (FeLV)-infected cats is associated with the emergence of a novel viral subgroup, FeLV-C. FeLV-C arises from the subgroup that is transmitted, FeLV-A, through alterations in the amino acid sequence of the receptor binding domain (RBD) of the envelope glycoprotein that result in a shift in the receptor usage and the cell tropism of the virus. The factors that influence the transition from subgroup A to subgroup C remain unclear, one possibility is that a selective pressure in the host drives the acquisition of mutations in the RBD, creating A/C intermediates with enhanced abilities to interact with the FeLV-C receptor, FLVCR. In order to understand further the emergence of FeLV-C in the infected cat, we examined primary isolates of FeLV-C for evidence of FeLV-A variants that bore mutations consistent with a gradual evolution from FeLV-A to FeLV-C.<p></p> <b>RESULTS:</b> Within each isolate of FeLV-C, we identified variants that were ostensibly subgroup A by nucleic acid sequence comparisons, but which bore mutations in the RBD. One such mutation, N91D, was present in multiple isolates and when engineered into a molecular clone of the prototypic FeLV-A (Glasgow-1), enhanced replication was noted in feline cells. Expression of the N91D Env on murine leukaemia virus (MLV) pseudotypes enhanced viral entry mediated by the FeLV-A receptor THTR1 while soluble FeLV-A Env bearing the N91D mutation bound more efficiently to mouse or guinea pig cells bearing the FeLV-A and -C receptors. Long-term in vitro culture of variants bearing the N91D substitution in the presence of anti-FeLV gp70 antibodies did not result in the emergence of FeLV-C variants, suggesting that additional selective pressures in the infected cat may drive the subsequent evolution from subgroup A to subgroup C.<p></p> <b>CONCLUSIONS:</b> Our data support a model in which variants of FeLV-A, bearing subtle differences in the RBD of Env, may be predisposed towards enhanced replication in vivo and subsequent conversion to FeLV-C. The selection pressures in vivo that drive the emergence of FeLV-C in a proportion of infected cats remain to be established

Unconscious biases in neural populations coding multiple stimuli

Throughout the nervous system information is commonly coded in activity distributed over populations of neurons. In idealized situations where a single, continuous stimulus is encoded in a homogeneous population code, the value of the encoded stimulus can be read out without bias. However in many situations multiple stimuli are simultaneously present, for example, multiple motion patterns might overlap. Here we find that when multiple stimuli that overlap in their neural representation are simultaneously encoded in the population, biases in the read-out emerge. Although the bias disappears in the absence of noise, the bias is remarkably persistent at low noise levels. The bias can be reduced by competitive encoding schemes or by employing complex decoders. To study the origin of the bias, we develop a novel general framework based on Gaussian processes that allows for an accurate calculation of the estimate distributions of maximum likelihood decoders, and reveals that the distribution of estimates is bimodal for overlapping stimuli. The results have implications for neural coding and behavioural experiments on, for instance, overlapping motion patterns

Pathogenic and genetic characterization of six Indian populations of Colletotrichum sublineolum, the causal agent of sorghum anthracnose

The pathogenic and genetic characterization of populations of C. sublineolum, the causal agent of anthracnose of sorghum, was investigated in isolates from 6 locations in India. Multi-location field evaluation and greenhouse tests were done on 16 sorghum lines that comprised the International Sorghum Anthracnose Virulence Nursery (ISAVN). The lines were tested in a field trial for 4-5 years (1992-96) at 6 locations: Indore, Surat, Patancheru, Dharwad, Udaipur and Pantnagar. Plants were scored for disease reaction (R/MR/S) and for disease severity (on a 1-9 scale where 1 is no lesions and 9 is >75% leaf area covered with lesions) at the soft-dough stage in the field and at the seedling stage in the greenhouse. Significant (P<0.001) differences were observed for virulence (disease reaction) and aggressiveness (disease severity) across locations (isolates) and sorghum lines both in field and greenhouse tests. In both tests, isolate x sorghum line interactions were highly significant (P<0.001) suggesting that populations of C. sublineolum at these 6 locations were different. A random amplified polymorphic DNA (RAPD) analysis exhibited genetic dissimilarities among the isolates and these were classified into 6 groups

Management evaluation of metastasis in the brain (MEMBRAIN)—a United Kingdom and Ireland prospective, multicenter observational study

Background: In recent years an increasing number of patients with cerebral metastasis (CM) have been referred to the neuro-oncology multidisciplinary team (NMDT). Our aim was to obtain a national picture of CM referrals to assess referral volume and quality and factors affecting NMDT decision making. / Methods: A prospective multicenter cohort study including all adult patients referred to NMDT with 1 or more CM was conducted. Data were collected in neurosurgical units from November 2017 to February 2018. Demographics, primary disease, KPS, imaging, and treatment recommendation were entered into an online database. / Results: A total of 1048 patients were analyzed from 24 neurosurgical units. Median age was 65 years (range, 21-93 years) with a median number of 3 referrals (range, 1-17 referrals) per NMDT. The most common primary malignancies were lung (36.5%, n = 383), breast (18.4%, n = 193), and melanoma (12.0%, n = 126). A total of 51.6% (n = 541) of the referrals were for a solitary metastasis and resulted in specialist intervention being offered in 67.5% (n = 365) of cases. A total of 38.2% (n = 186) of patients being referred with multiple CMs were offered specialist treatment. NMDT decision making was associated with number of CMs, age, KPS, primary disease status, and extent of extracranial disease (univariate logistic regression, P < .001) as well as sentinel location and tumor histology (P < .05). A delay in reaching an NMDT decision was identified in 18.6% (n = 195) of cases. / Conclusions: This study demonstrates a changing landscape of metastasis management in the United Kingdom and Ireland, including a trend away from adjuvant whole-brain radiotherapy and specialist intervention being offered to a significant proportion of patients with multiple CMs. Poor quality or incomplete referrals cause delay in NMDT decision making

MARS an improved de novo peptide candidate selection method for non-canonical antigen target discovery in cancer

Understanding the nature and extent of non-canonical human leukocyte antigen (HLA) presentation in tumour cells is a priority for target antigen discovery for the development of next generation immunotherapies in cancer. We here employ a de novo mass spectrometric sequencing approach with a refined, MHC-centric analysis strategy to detect non-canonical MHC-associated peptides specific to cancer without any prior knowledge of the target sequence from genomic or RNA sequencing data. Our strategy integrates MHC binding rank, Average local confidence scores, and peptide Retention time prediction for improved de novo candidate Selection; culminating in the machine learning model MARS. We benchmark our model on a large synthetic peptide library dataset and reanalysis of a published dataset of high-quality non-canonical MHC-associated peptide identifications in human cancer. We achieve almost 2-fold improvement for high quality spectral assignments in comparison to de novo sequencing alone with an estimated accuracy of above 85.7% when integrated with a stepwise peptide sequence mapping strategy. Finally, we utilize MARS to detect and validate lncRNA-derived peptides in human cervical tumour resections, demonstrating its suitability to discover novel, immunogenic, non-canonical peptide sequences in primary tumour tissue

Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine

In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown

CXCR4-expressing Mist1\u3csup\u3e+\u3c/sup\u3e progenitors in the gastric antrum contribute to gastric cancer development

Mist1 was recently shown to identify a discrete population of stem cells within the isthmus of the oxyntic gland within the gastric corpus. Chief cells at the base of the gastric corpus also express Mist1. The relevance of Mist1 expression as a marker of specific cell populations within the antral glands of the distal stomach, however, is unknown. Using Mist1-CreERT mice, we revealed that Mist1+ antral cells, distinct from the Mist1+ population in the corpus, comprise long-lived progenitors that reside within the antral isthmus above Lgr5+ or CCK2R+ cells. Mist1+ antral progenitors can serve as an origin of antral tumors induced by loss of Apc or MNU treatment. Mist1+ antral progenitors, as well as other antral stem/progenitor population, express Cxcr4, and are located in close proximity to Cxcl12 (the Cxcr4 ligand)-expressing endothelium. During antral carcinogenesis, there is an expansion of Cxcr4+ epithelial cells as well as the Cxcl12+ perivascular niche. Deletion of Cxcl12 in endothelial cells or pharmacological blockade of Cxcr4 inhibits antral tumor growth. Cxcl12/Cxcr4 signaling may be a potential therapeutic target

Itraconazole associated quadriparesis and edema: a case report

<p>Abstract</p> <p>Introduction</p> <p>Itraconazole is an anti-fungal agent widely used to treat various forms of mycosis. It is particularly useful in allergic bronchopulmonary aspergillosis and severe asthma with fungal sensitization. Side effects are uncommon and usually mild. Mild neuropathy is noted to occur very rarely. We present an unusual and, to the best of our knowledge, as yet unreported case of severe neuropathy and peripheral edema due to itraconazole in the absence of a concomitant risk factor.</p> <p>Case presentation</p> <p>A 72-year-old Caucasian man was started on itraconazole following diagnosis of severe asthma with fungal sensitization. One month later he presented with severe bilateral ankle edema with an elevated serum itraconazole level. The itraconazole dose was reduced but his ankle edema persisted and he developed weakness of all four limbs. Itraconazole was completely stopped leading to improvement in his leg edema but he became bed bound due to weakness. He gradually improved with supportive care and neurorehabilitation. On review at six months, our patient was able to mobilize with the aid of two elbow crutches and power had returned to 5/5 in distal extremities and 4+/5 in proximal extremities. The diagnosis was established based on the classical presentation of drug-induced neuropathy and negative investigatory findings for any alternative diagnoses.</p> <p>Conclusion</p> <p>We report the case of a patient presenting with an unusual complication of severe neuropathy and peripheral edema due to itraconazole. Clinicians should be alert to this association when encountered with neuropathy and/or edema in an itraconazole therapy recipient.</p