130 research outputs found
Studies of the gastro-oesophageal junction in normal and overweight healthy volunteers
Introduction: Oesophageal adenocarcinoma has increased dramatically in incidence over the past three decades with a particularly high burden of disease at the gastro-oesophageal junction. Many cases occur in individuals without known gastro-oesophageal reflux disease and in the absence of Barrettâs oesophagus suggesting that mechanisms other than traditional reflux may be important.
Distal squamous mucosa may be prone to acid damage even in the absence of traditional reflux by the mechanism of distal opening of the lower oesophageal sphincter. This is splaying of the distal segment of lower oesophageal sphincter allowing acid ingress without traditional reflux.
It has been suggested that the cardiac mucosa at the gastro-oesophageal junction, separating oesophageal squamous mucosa and acid secreting columnar mucosa of the stomach may be an abnormal mucosa arising as a consequence of acid damage. By this theory the cardiac mucosa is metaplastic and akin to ultra-short Barrettâs oesophagus.
Obesity is a known risk factor for adenocarcinoma at the gastro-oesophageal junction and its rise has paralleled that of oesophageal cancer. Some of this excess risk undoubtedly operates through stress on the gastro-oesophageal junction and a predisposition to reflux. However we sought to explore the impact of obesity on the gastro-oesophageal junction in healthy volunteers without reflux and in particular to determine the characteristics of the cardiac mucosa and mechanisms of reflux in this group.
Methods: 61 healthy volunteers with normal and increased waist circumference were recruited. 15 were found to have a hiatus hernia during the study protocol and were analysed separately. Volunteers had comprehensive pathological, physiological and anatomical assessments of the gastro-oesophageal junction including endoscopy with biopsies, MRI scanning before and after a standardised meal, prolonged recording of pH and manometry before and after a meal and screening by fluoroscopy to identify the squamo-columnar junction.
In the course of the early manometric assessments a potential error associated with the manometry system recordings was identified. We therefore also sought to document and address this on the benchtop and in vivo.
Key Findings:
1. In documenting the behaviour of the manoscan we described an immediate effect of temperature change on the pressure recorded by the sensors; âthermal effectâ and an ongoing drift of the recorded pressure with time; âbaseline driftâ. Thermal effect was well compensated within the standard operation of the system but baseline drift not addressed. Applying a linear correction to recorded data substantially reduced the error associated with baseline drift.
2. In asymptomatic healthy volunteers there was lengthening of the cardiac mucosa in association with central obesity and age. Furthermore, the cardiac mucosa in healthy volunteers demonstrated an almost identical immunophenotype to non-IM Barrettâs mucosa, which is considered to arise by metaplasia of oesophageal squamous mucosa. These findings support the hypothesis that the cardia is metaplastic in origin.
3. We have demonstrated a plausible mechanism of damage to distal squamous mucosa in association with obesity. In those with a large waist circumference we observed increased ingress of acid within but not across the lower oesophageal sphincter; âintrasphincteric refluxâ
4. The 15 healthy volunteers with a hiatus hernia were compared to 15 controls matched for age, gender and waist circumference. Those with a hiatus hernia had a longer cardiac mucosa and although they did not have excess traditional reflux they had excess distal acid exposure by short segment acid reflux and intrasphincteric acid reflux.
Conclusions: These findings are likely to be relevant to adenocarcinoma of the gastro-oesophageal junctio
The Erotic and the Vulgar: Visual Culture and Organized Labor's Critique of U.S. Hegemony in Occupied Japan
This essay engages the colonial legacy of postwar Japan by arguing that the political cartoons produced as part of the postwar Japanese labor movementâs critique of U.S. cultural hegemony illustrate how gendered discourses underpinned,
and sometimes undermined, the ideologies formally represented by visual artists and the organizations that funded them. A significant component of organized
laborâs propaganda rested on a corpus of visual media that depicted women as icons of Japanese national culture. Japanâs most militant labor unions were propagating anti-imperialist discourses that invoked an engendered/endangered nation that accentuated the importance of union roles for men by subordinating, then eliminating, union roles for women
The mannose receptor (CD206) identifies a population of colonic macrophages in health and inflammatory bowel disease
To understand the contribution of mononuclear phagocytes (MNP), which include monocyte-derived intestinal macrophages, to the pathogenesis of inflammatory bowel disease (IBD), it is necessary to identify functionally-different MNP populations. We aimed to characterise intestinal macrophage populations in patients with IBD. We developed 12-parameter flow cytometry protocols to identify and human intestinal MNPs. We used these protocols to purify and characterize colonic macrophages from colonic tissue from patients with Crohnâs disease (CD), ulcerative colitis (UC), or non-inflamed controls, in a cross-sectional study. We identify macrophage populations (CD45+CD64+ HLA-DR+) and describe two distinct subsets, differentiated by their expression of the mannose receptor, CD206. CD206+ macrophages expressed markers consistent with a mature phenotype: high levels of CD68 and CD163, higher transcription of IL-10 and lower expression of TREM1. CD206â macrophages appear to be less mature, with features more similar to their monocytic precursors. We identified and purified macrophage populations from human colon. These appear to be derived from a monocytic precursor with high CCR2 and low CD206 expression. As these cells mature, they acquire expression of IL-10, CD206, CD63, and CD168. Targeting the newly recruited monocyte-derived cells may represent a fruitful avenue to ameliorate chronic inflammation in IBD
Genomic, Pathway Network, and Immunologic Features Distinguishing Squamous Carcinomas
This integrated, multiplatform PanCancer Atlas study co-mapped and identified distinguishing
molecular features of squamous cell carcinomas (SCCs) from five sites associated with smokin
The development of descending projections from the brainstem to the spinal cord in the fetal sheep
<p>Abstract</p> <p>Background</p> <p>Although the fetal sheep is a favoured model for studying the ontogeny of physiological control systems, there are no descriptions of the timing of arrival of the projections of supraspinal origin that regulate somatic and visceral function. In the early development of birds and mammals, spontaneous motor activity is generated within spinal circuits, but as development proceeds, a distinct change occurs in spontaneous motor patterns that is dependent on the presence of intact, descending inputs to the spinal cord. In the fetal sheep, this change occurs at approximately 65 days gestation (G65), so we therefore hypothesised that spinally-projecting axons from the neurons responsible for transforming fetal behaviour must arrive at the spinal cord level shortly before G65. Accordingly we aimed to identify the brainstem neurons that send projections to the spinal cord in the mature sheep fetus at G140 (term = G147) with retrograde tracing, and thus to establish whether any projections from the brainstem were absent from the spinal cord at G55, an age prior to the marked change in fetal motor activity has occurred.</p> <p>Results</p> <p>At G140, CTB labelled cells were found within and around nuclei in the reticular formation of the medulla and pons, within the vestibular nucleus, raphe complex, red nucleus, and the nucleus of the solitary tract. This pattern of labelling is similar to that previously reported in other species. The distribution of CTB labelled neurons in the G55 fetus was similar to that of the G140 fetus.</p> <p>Conclusion</p> <p>The brainstem nuclei that contain neurons which project axons to the spinal cord in the fetal sheep are the same as in other mammalian species. All projections present in the mature fetus at G140 have already arrived at the spinal cord by approximately one third of the way through gestation. The demonstration that the neurons responsible for transforming fetal behaviour in early ontogeny have already reached the spinal cord by G55, an age well before the change in motor behaviour occurs, suggests that the projections do not become fully functional until well after their arrival at the spinal cord.</p
Pan-Cancer Analysis of lncRNA Regulation Supports Their Targeting of Cancer Genes in Each Tumor Context
Long noncoding RNAs (lncRNAs) are commonly dys-regulated in tumors, but only a handful are known toplay pathophysiological roles in cancer. We inferredlncRNAs that dysregulate cancer pathways, onco-genes, and tumor suppressors (cancer genes) bymodeling their effects on the activity of transcriptionfactors, RNA-binding proteins, and microRNAs in5,185 TCGA tumors and 1,019 ENCODE assays.Our predictions included hundreds of candidateonco- and tumor-suppressor lncRNAs (cancerlncRNAs) whose somatic alterations account for thedysregulation of dozens of cancer genes and path-ways in each of 14 tumor contexts. To demonstrateproof of concept, we showed that perturbations tar-geting OIP5-AS1 (an inferred tumor suppressor) andTUG1 and WT1-AS (inferred onco-lncRNAs) dysre-gulated cancer genes and altered proliferation ofbreast and gynecologic cancer cells. Our analysis in-dicates that, although most lncRNAs are dysregu-lated in a tumor-specific manner, some, includingOIP5-AS1, TUG1, NEAT1, MEG3, and TSIX, synergis-tically dysregulate cancer pathways in multiple tumorcontexts
Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas
Although theMYConcogene has been implicated incancer, a systematic assessment of alterations ofMYC, related transcription factors, and co-regulatoryproteins, forming the proximal MYC network (PMN),across human cancers is lacking. Using computa-tional approaches, we define genomic and proteo-mic features associated with MYC and the PMNacross the 33 cancers of The Cancer Genome Atlas.Pan-cancer, 28% of all samples had at least one ofthe MYC paralogs amplified. In contrast, the MYCantagonists MGA and MNT were the most frequentlymutated or deleted members, proposing a roleas tumor suppressors.MYCalterations were mutu-ally exclusive withPIK3CA,PTEN,APC,orBRAFalterations, suggesting that MYC is a distinct onco-genic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such asimmune response and growth factor signaling; chro-matin, translation, and DNA replication/repair wereconserved pan-cancer. This analysis reveals insightsinto MYC biology and is a reference for biomarkersand therapeutics for cancers with alterations ofMYC or the PMN
Spatial Organization and Molecular Correlation of Tumor-Infiltrating Lymphocytes Using Deep Learning on Pathology Images
Beyond sample curation and basic pathologic characterization, the digitized H&E-stained images
of TCGA samples remain underutilized. To highlight this resource, we present mappings of tumorinfiltrating lymphocytes (TILs) based on H&E images from 13 TCGA tumor types. These TIL
maps are derived through computational staining using a convolutional neural network trained to
classify patches of images. Affinity propagation revealed local spatial structure in TIL patterns and
correlation with overall survival. TIL map structural patterns were grouped using standard
histopathological parameters. These patterns are enriched in particular T cell subpopulations
derived from molecular measures. TIL densities and spatial structure were differentially enriched
among tumor types, immune subtypes, and tumor molecular subtypes, implying that spatial
infiltrate state could reflect particular tumor cell aberration states. Obtaining spatial lymphocytic
patterns linked to the rich genomic characterization of TCGA samples demonstrates one use for
the TCGA image archives with insights into the tumor-immune microenvironment
Proneoplastic effects of PGE2 mediated by EP4 receptor in colorectal cancer
<p>Abstract</p> <p>Background</p> <p>Prostaglandin E<sub>2 </sub>(PGE<sub>2</sub>) is the major product of Cyclooxygenase-2 (COX-2) in colorectal cancer (CRC). We aimed to assess PGE<sub>2 </sub>cell surface receptors (EP 1â4) to examine the mechanisms by which PGE<sub>2 </sub>regulates tumour progression.</p> <p>Methods</p> <p>Gene expression studies were performed by quantitative RT-PCR. Cell cycle was analysed by flow cytometry with cell proliferation quantified by BrdU incorporation measured by enzyme immunoassay. Immunohistochemistry was employed for expression studies on formalin fixed paraffin embedded tumour tissue.</p> <p>Results</p> <p>EP4 was the most abundant subtype of PGE<sub>2 </sub>receptor in HT-29 and HCA7 cells (which show COX-2 dependent PGE<sub>2 </sub>generation) and was consistently the most abundant transcript in human colorectal tumours (n = 8) by qRT-PCR (ANOVA, p = 0.01). G0/G1 cell cycle arrest was observed in HT-29 cells treated with SC-236 5 ÎŒM (selective COX-2 inhibitor) for 24 hours (p = 0.02), an effect abrogated by co-incubation with PGE<sub>2 </sub>(1 ÎŒM). G0/G1 arrest was also seen with a specific EP4 receptor antagonist (EP4A, L-161982) (p = 0.01). Treatment of HT-29 cells with either SC-236 or EP4A caused reduction in intracellular cAMP (ANOVA, p = 0.01). Early induction in p21<sup>WAF1/CIP1 </sup>expression (by qRT-PCR) was seen with EP4A treatment (mean fold increase 4.4, p = 0.04) while other genes remained unchanged. Similar induction in p21<sup>WAF1/CIP1 </sup>was also seen with PD153025 (1 ÎŒM), an EGFR tyrosine kinase inhibitor, suggesting EGFR transactivation by EP4 as a potential mechanism. Additive inhibition of HCA7 proliferation was observed with the combination of SC-236 and neutralising antibody to amphiregulin (AR), a soluble EGFR ligand. Concordance in COX-2 and AR localisation in human colorectal tumours was noted.</p> <p>Conclusion</p> <p>COX-2 regulates cell cycle transition via EP4 receptor and altered p21<sup>WAF1/CIP1 </sup>expression. EGFR pathways appear important. Specific targeting of the EP4 receptor or downstream targets may offer a safer alternative to COX-2 inhibition in the chemoprevention of CRC.</p
Pathogenesis and Host Response in Syrian Hamsters following Intranasal Infection with Andes Virus
Hantavirus pulmonary syndrome (HPS), also referred to as hantavirus cardiopulmonary syndrome (HCPS), is a rare but frequently fatal disease caused by New World hantaviruses. In humans HPS is associated with severe pulmonary edema and cardiogenic shock; however, the pathogenesis of this disease remains unclear largely due to a lack of suitable animal models for the study of disease progression. In this study we monitored clinical, virological, pathophysiological parameters and host immunological responses to decipher pathological factors and events in the lethal Syrian hamster model of HPS following intranasal inoculation of Andes virus. Transcriptional profiling of the host gene responses demonstrated a suppression of innate immune responses in most organs analyzed during the early stage of infection, except for in the lung which had low level activation of several pro-inflammatory genes. During this phase Andes virus established a systemic infection in hamsters, with viral antigen readily detectable in the endothelium of the majority of tissues analyzed by 7â8 days post-inoculation. Despite wide-spread infection, histological analysis confirmed pathological abnormalities were almost exclusively found in the lungs. Immediately preceding clinical signs of disease, intense activation of pro-inflammatory and Th1/Th2 responses were observed in the lungs as well as the heart, but not in peripheral organs, suggesting that localized immune-modulations by infection is paramount to pathogenesis. Throughout the course of infection a strong suppression of regulatory T-cell responses was noted and is hypothesized to be the basis of the aberrant immune activations. The unique and comprehensive monitoring of host immune responses to hantavirus infection increases our understanding of the immuno-pathogenesis of HPS and will facilitate the development of treatment strategies targeting deleterious host immunological responses
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