Nontargeted screening using gas chromatography– atmospheric pressure ionization mass spectrometry: Recent trends and emerging potential

Gas chromatography–high-resolution mass spectrometry (GC–HRMS) is a powerful non-targeted screening technique that promises to accelerate the identification of environmental pollu-tants. Currently, most GC–HRMS instruments are equipped with electron ionization (EI), but atmospheric pressure ionization (API) ion sources have attracted renewed interest because: (i) colli-sional cooling at atmospheric pressure minimizes fragmentation, resulting in an increased yield of molecular ions for elemental composition determination and improved detection limits; (ii) a wide range of sophisticated tandem (ion mobility) mass spectrometers can be easily adapted for opera-tion with GC–API; and (iii) the conditions of an atmospheric pressure ion source can promote structure diagnostic ion–molecule reactions that are otherwise difficult to perform using conventional GC–MS instrumentation. This literature review addresses the merits of GC–API for nontargeted screening while summarizing recent applications using various GC–API techniques. One perceived drawback of GC–API is the paucity of spectral libraries that can be used to guide structure elucida-tion. Herein, novel data acquisition, deconvolution and spectral prediction tools will be reviewed. With continued development, it is anticipated that API may eventually supplant EI as the de facto GC–MS ion source used to identify unknowns

In Vitro Effects of Budesonide on Eosinophil-Basophil Lineage Commitment

IL-5 is the primary cytokine that stimulates the production and survival of eosinophils and basophils from progenitor cells. The inhaled glucocorticoid, budesonide, has been shown to exert a therapeutic effect via suppression of eosinophil/basophil progenitors in vivo. Since various steroids have exhibited the ability to enhance eosinophil/basophil progenitor differentiation, we examined the effects of budesonide in vitro. Bone marrow and cord blood samples were obtained and cultured in the presence of IL-5 alone or IL-5 plus budesonide. Eosinophil/basophil colony-forming units were enumerated from cultured nonadherent mononuclear cells and from purified CD34+ cells. CD34+ cells with and without budesonide were also examined for up-regulation of ERK1/2, MAPK and GATA-1 using real time-PCR. Results: i) up-regulation of eosinophil/basophil colony-forming units is due to the direct effects of budesonide on IL-5-stimulated progenitors; ii) GATA-1 is likely involved in the early amplification of eosinophil/basophil progenitor commitment leading to increased differentiation. A potential transcriptional pathway has been identified which may mediate the effects of budesonide on eosinophil/basophil lineage commitment

Concentration-dependent exchange accelerates turnover of proteins bound to double-stranded DNA

The multistep kinetics through which DNA-binding proteins bind their targets are heavily studied, but relatively little attention has been paid to proteins leaving the double helix. Using single-DNA stretching and fluorescence detection, we find that sequence-neutral DNA-binding proteins Fis, HU and NHP6A readily exchange with themselves and with each other. In experiments focused on the Escherichia coli nucleoid-associated protein Fis, only a small fraction of protein bound to DNA spontaneously dissociates into protein-free solution. However, if Fis is present in solution, we find that a concentration-dependent exchange reaction occurs which turns over the bound protein, with a rate of kexch = 6 × 104 M−1s−1. The bacterial DNA-binding protein HU and the yeast HMGB protein NHP6A display the same phenomenon of protein in solution accelerating dissociation of previously bound labeled proteins as exchange occurs. Thus, solvated proteins can play a key role in facilitating removal and renewal of proteins bound to the double helix, an effect that likely plays a major role in promoting the turnover of proteins bound to DNA in vivo and, therefore, in controlling the dynamics of gene regulation

Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial.

BACKGROUND: Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised International Carotid Stenting Study comparison of these treatments. METHODS: Patients with symptomatic carotid stenosis were randomly assigned 1:1 to open treatment with stenting or endarterectomy at 50 centres worldwide. Randomisation was computer generated centrally and allocated by telephone call or fax. Major outcomes were assessed by an independent endpoint committee unaware of treatment assignment. The primary endpoint was fatal or disabling stroke in any territory after randomisation to the end of follow-up. Analysis was by intention to treat ([ITT] all patients) and per protocol from 31 days after treatment (all patients in whom assigned treatment was completed). Functional ability was rated with the modified Rankin scale. This study is registered, number ISRCTN25337470. FINDINGS: 1713 patients were assigned to stenting (n=855) or endarterectomy (n=858) and followed up for a median of 4·2 years (IQR 3·0-5·2, maximum 10·0). Three patients withdrew immediately and, therefore, the ITT population comprised 1710 patients. The number of fatal or disabling strokes (52 vs 49) and cumulative 5-year risk did not differ significantly between the stenting and endarterectomy groups (6·4% vs 6·5%; hazard ratio [HR] 1·06, 95% CI 0·72-1·57, p=0·77). Any stroke was more frequent in the stenting group than in the endarterectomy group (119 vs 72 events; ITT population, 5-year cumulative risk 15·2% vs 9·4%, HR 1·71, 95% CI 1·28-2·30, p<0·001; per-protocol population, 5-year cumulative risk 8·9% vs 5·8%, 1·53, 1·02-2·31, p=0·04), but were mainly non-disabling strokes. The distribution of modified Rankin scale scores at 1 year, 5 years, or final follow-up did not differ significantly between treatment groups. INTERPRETATION: Long-term functional outcome and risk of fatal or disabling stroke are similar for stenting and endarterectomy for symptomatic carotid stenosis. FUNDING: Medical Research Council, Stroke Association, Sanofi-Synthélabo, European Union

Fatigue after Stroke: Baseline Predictors and Influence on Survival. Analysis of Data from UK Patients Recruited in the International Stroke Trial

Little is known about the associations of post-stroke fatigue or its influence on survival. The vitality component of the Short Form 36 (SF-36) is a valid and reliable measure of post-stroke fatigue. We sought to identify associates of post-stroke fatigue and determine whether fatigue predicted survival.We used SF-36 vitality scores obtained by postal questionnaires from 1080 UK patients randomised in the International Stroke Trial, at a mean of 64 weeks after stroke onset. We used logistic regression to explore factors at randomisation which predicted SF-36 vitality at follow-up, and the relationship between SF-36 vitality and both SF-36 mental health and SF-36 emotional role function at follow-up. We used Cox proportional hazards to explore the influence of SF-36 vitality at follow-up on subsequent survival, using four different statistical models for handling missing data.Female sex, increasing age, lower mental health and lower emotional role function scores were associated with greater degrees of fatigue after stroke (i.e. lower vitality scores) but these factors explained <30% of the variance (R(2)) in fatigue. In two models, fatigue at follow-up was associated with shorter subsequent survival.Increasing age, female sex, emotional role function and mental health were associated with increased fatigue at a mean of 64 weeks after stroke onset, but explained less than 30% of the variance. Fatigue was associated with reduced subsequent long-term survival in 2/4 models. Further work is needed to identify the biological substrate of fatigue and to clarify its influence on survival

Association of nucleoid proteins with coding and non-coding segments of the Escherichia coli genome

The Escherichia coli chromosome is condensed into an ill-defined structure known as the nucleoid. Nucleoid-associated DNA-binding proteins are involved in maintaining this structure and in mediating chromosome compaction. We have exploited chromatin immunoprecipitation and high-density microarrays to study the binding of three such proteins, FIS, H-NS and IHF, across the E.coli genome in vivo. Our results show that the distribution of these proteins is biased to intergenic parts of the genome, and that the binding profiles overlap. Hence some targets are associated with combinations of bound FIS, H-NS and IHF. In addition, many regions associated with FIS and H-NS are also associated with RNA polymerase

Multidisciplinary consensus guideline for the diagnosis and management of spontaneous intracranial hypotension

BACKGROUND: We aimed to create a multidisciplinary consensus clinical guideline for best practice in the diagnosis, investigation and management of spontaneous intracranial hypotension (SIH) due to cerebrospinal fluid leak based on current evidence and consensus from a multidisciplinary specialist interest group (SIG). METHODS: A 29-member SIG was established, with members from neurology, neuroradiology, anaesthetics, neurosurgery and patient representatives. The scope and purpose of the guideline were agreed by the SIG by consensus. The SIG then developed guideline statements for a series of question topics using a modified Delphi process. This process was supported by a systematic literature review, surveys of patients and healthcare professionals and review by several international experts on SIH. RESULTS: SIH and its differential diagnoses should be considered in any patient presenting with orthostatic headache. First-line imaging should be MRI of the brain with contrast and the whole spine. First-line treatment is non-targeted epidural blood patch (EBP), which should be performed as early as possible. We provide criteria for performing myelography depending on the spine MRI result and response to EBP, and we outline principles of treatments. Recommendations for conservative management, symptomatic treatment of headache and management of complications of SIH are also provided. CONCLUSIONS: This multidisciplinary consensus clinical guideline has the potential to increase awareness of SIH among healthcare professionals, produce greater consistency in care, improve diagnostic accuracy, promote effective investigations and treatments and reduce disability attributable to SIH

KRAS(G12D) and TP53(R167H) Cooperate to Induce Pancreatic Ductal Adenocarcinoma in Sus scrofa Pigs

Although survival has improved in recent years, the prognosis of patients with advanced pancreatic ductal adenocarcinoma (PDAC) remains poor. Despite substantial differences in anatomy, physiology, genetics, and metabolism, the overwhelming majority of preclinical testing relies on transgenic mice. Hence, while mice have allowed for tremendous advances in cancer biology, they have been a poor predictor of drug performance/toxicity in the clinic. Given the greater similarity of sus scrofa pigs to humans, we engineered transgenic sus scrofa expressing a LSL-KRASG12D-TP53R167H cassette. By applying Adeno-Cre to pancreatic duct cells in vitro, cells self-immortalized and established tumors in immunocompromised mice. When Adeno-Cre was administered to the main pancreatic duct in vivo, pigs developed extensive PDAC at the injection site hallmarked by excessive proliferation and desmoplastic stroma. This serves as the first large animal model of pancreatic carcinogenesis, and may allow for insight into new avenues of translational research not before possible in rodents

Long-Term Gemcitabine Treatment Reshapes the Pancreatic Tumor Microenvironment and Sensitizes Murine Carcinoma to Combination Immunotherapy

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related death with a median survival time of 6–12 months. Most patients present with disseminated disease and the majority are offered palliative chemotherapy. With no approved treatment modalities for patients who progress on chemotherapy, we explored the effects of long-term Gemcitabine on the tumor microenvironment in order to identify potential therapeutic options for chemo-refractory PDAC. Using a combination of mouse models, primary cell line-derived xenografts, and established tumor cell lines, we first evaluated chemotherapy-induced alterations in the tumor secretome and immune surface proteins by high throughput proteomic arrays. In addition to enhancing antigen presentation and immune checkpoint expression, Gemcitabine consistently increased the synthesis of CCL/CXCL chemokines and TGFβ-associated signals. These secreted factors altered the composition of the tumor stroma, conferring Gemcitabine resistance to cancer-associated fibroblasts in vitro and further enhancing TGFβ1 biosynthesis. Combined Gemcitabine and anti-PD-1 treatment in transgenic models of murine PDAC failed to alter disease course unless mice also underwent genetic or pharmacologic ablation of TGFβ signaling. In the setting of TGFβ signaling deficiency, Gemcitabine and anti-PD-1 led to a robust CD8+ T-cell response and decrease in tumor burden, markedly enhancing overall survival. These results suggest that Gemcitabine successfully primes PDAC tumors for immune checkpoint inhibition by enhancing antigen presentation only following disruption of the immunosuppressive cytokine barrier. Given the current lack of third-line treatment options, this approach warrants consideration in the clinical management of Gemcitabine-refractory PDAC