Publications by authors named "Nicholas J Taylor"

47 Publications

Metabolomics of primary cutaneous melanoma and matched adjacent extratumoral microenvironment.

PLoS One 2020 27;15(10):e0240849. Epub 2020 Oct 27.

Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida, United States of America.

Background: Melanoma causes the vast majority of deaths attributable to skin cancer, largely due to its propensity for metastasis. To date, few studies have examined molecular changes between primary cutaneous melanoma and adjacent putatively normal skin. To broaden temporal inferences related to initiation of disease, we performed a metabolomics investigation of primary melanoma and matched extratumoral microenvironment (EM) tissues; and, to make inferences about progressive disease, we also compared unmatched metastatic melanoma tissues to EM tissues.

Methods: Ultra-high performance liquid chromatography-mass spectrometry-based metabolic profiling was performed on frozen human tissues.

Results: We observed 824 metabolites as differentially abundant among 33 matched tissue samples, and 1,118 metabolites as differentially abundant between metastatic melanoma (n = 46) and EM (n = 34) after false discovery rate (FDR) adjustment (p<0.01). No significant differences in metabolite abundances were noted comparing primary and metastatic melanoma tissues.

Conclusions: Overall, pathway-based results significantly distinguished melanoma tissues from EM in the metabolism of: ascorbate and aldarate, propanoate, tryptophan, histidine, and pyrimidine. Within pathways, the majority of individual metabolite abundances observed in comparisons of primary melanoma vs. EM and metastatic melanoma vs. EM were directionally consistent. This observed concordance suggests most identified compounds are implicated in the initiation or maintenance of melanoma.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0240849PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591037PMC
December 2020

Manual and automated Cu-mediated radiosynthesis of the PARP inhibitor [F]olaparib.

Nat Protoc 2020 04 28;15(4):1525-1541. Epub 2020 Feb 28.

Chemistry Research Laboratory, University of Oxford, Oxford, UK.

Positron emission tomography (PET) is a diagnostic nuclear imaging modality that relies on automated protocols to prepare agents labeled with a positron-emitting radionuclide (e.g., F). In recent years, new reactions have appeared for the F-labeling of agents that are difficult to access by applying traditional radiochemistry, for example those requiring F incorporation into unactivated (hetero)arenes. However, automation of these new methods for translation to the clinic has progressed slowly because extensive modification of manual protocols is typically required when implementing novel F-labeling methodologies within automated modules. Here, we describe the workflow that led to the automated radiosynthesis of the poly(ADP-ribose) polymerase (PARP) inhibitor [F]olaparib. First, we established a robust manual protocol to prepare [F]olaparib from the protected N-[2-(trimethylsilyl)ethoxy]methyl (SEM) arylboronate ester precursor in a 17% ± 5% (n = 15; synthesis time, 135 min) non-decay-corrected (NDC) activity yield, with molar activity (A) up to 34.6 GBq/µmol. Automation of the process, consisting of copper-mediated F-fluorodeboronation followed by deprotection, was achieved on an Eckert & Ziegler Modular-Lab radiosynthesis platform, affording [F]olaparib in a 6% ± 5% (n = 3; synthesis time, 120 min) NDC activity yield with A up to 319 GBq/µmol.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41596-020-0295-7DOI Listing
April 2020

70 years of JSFA.

J Sci Food Agric 2020 01;100(1)

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jsfa.10142DOI Listing
January 2020

Estimating CDKN2A mutation carrier probability among global familial melanoma cases using GenoMELPREDICT.

J Am Acad Dermatol 2019 Aug 5;81(2):386-394. Epub 2019 Feb 5.

Department of Clinical Sciences, Lund University Hospital Lund, Sweden; Department of Surgery, Lund University Hospital, Lund, Sweden.

Background: Although rare in the general population, highly penetrant germline mutations in CDKN2A are responsible for 5%-40% of melanoma cases reported in melanoma-prone families. We sought to determine whether MELPREDICT was generalizable to a global series of families with melanoma and whether performance improvements can be achieved.

Methods: In total, 2116 familial melanoma cases were ascertained by the international GenoMEL Consortium. We recapitulated the MELPREDICT model within our data (GenoMELPREDICT) to assess performance improvements by adding phenotypic risk factors and history of pancreatic cancer. We report areas under the curve (AUC) with 95% confidence intervals (CIs) along with net reclassification indices (NRIs) as performance metrics.

Results: MELPREDICT performed well (AUC 0.752, 95% CI 0.730-0.775), and GenoMELPREDICT performance was similar (AUC 0.748, 95% CI 0.726-0.771). Adding a reported history of pancreatic cancer yielded discriminatory improvement (P < .0001) in GenoMELPREDICT (AUC 0.772, 95% CI 0.750-0.793, NRI 0.40). Including phenotypic risk factors did not improve performance.

Conclusion: The MELPREDICT model functioned well in a global data set of familial melanoma cases. Adding pancreatic cancer history improved model prediction. GenoMELPREDICT is a simple tool for predicting CDKN2A mutational status among melanoma patients from melanoma-prone families and can aid in directing these patients to receive genetic testing or cancer risk counseling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jaad.2019.01.079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6634996PMC
August 2019

Germline Variation at CDKN2A and Associations with Nevus Phenotypes among Members of Melanoma Families.

J Invest Dermatol 2017 12 19;137(12):2606-2612. Epub 2017 Aug 19.

Melanoma Institute Australia, Westmead, New South Wales, Australia; Westmead Institute for Cancer Research, University of Sydney at Westmead Millennium Institute, New South Wales, Australia.

Germline mutations in CDKN2A are frequently identified among melanoma kindreds and are associated with increased atypical nevus counts. However, a clear relationship between pathogenic CDKN2A mutation carriage and other nevus phenotypes including counts of common acquired nevi has not yet been established. Using data from GenoMEL, we investigated the relationships between CDKN2A mutation carriage and 2-mm, 5-mm, and atypical nevus counts among blood-related members of melanoma families. Compared with individuals without a pathogenic mutation, those who carried one had an overall higher prevalence of atypical (odds ratio = 1.64; 95% confidence interval = 1.18-2.28) nevi but not 2-mm nevi (odds ratio = 1.06; 95% confidence interval = 0.92-1.21) or 5-mm nevi (odds ratio = 1.26; 95% confidence interval = 0.94-1.70). Stratification by case status showed more pronounced positive associations among non-case family members, who were nearly three times (odds ratio = 2.91; 95% confidence interval = 1.75-4.82) as likely to exhibit nevus counts at or above the median in all three nevus categories simultaneously when harboring a pathogenic mutation (vs. not harboring one). Our results support the hypothesis that unidentified nevogenic genes are co-inherited with CDKN2A and may influence carcinogenesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jid.2017.07.829DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5701856PMC
December 2017

Derisking the Cu-Mediated F-Fluorination of Heterocyclic Positron Emission Tomography Radioligands.

J Am Chem Soc 2017 06 12;139(24):8267-8276. Epub 2017 Jun 12.

University of Oxford , Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.

Molecules labeled with fluorine-18 (F) are used in positron emission tomography to visualize, characterize and measure biological processes in the body. Despite recent advances in the incorporation of F onto arenes, the development of general and efficient approaches to label radioligands necessary for drug discovery programs remains a significant task. This full account describes a derisking approach toward the radiosynthesis of heterocyclic positron emission tomography (PET) radioligands using the copper-mediated F-fluorination of aryl boron reagents with F-fluoride as a model reaction. This approach is based on a study examining how the presence of heterocycles commonly used in drug development affects the efficiency of F-fluorination for a representative aryl boron reagent, and on the labeling of more than 50 (hetero)aryl boronic esters. This set of data allows for the application of this derisking strategy to the successful radiosynthesis of seven structurally complex pharmaceutically relevant heterocycle-containing molecules.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.7b03131DOI Listing
June 2017

Enhanced copper-mediated (18)F-fluorination of aryl boronic esters provides eight radiotracers for PET applications.

Chem Commun (Camb) 2016 Jun;52(54):8361-4

University of Oxford, Chemistry Research Laboratory, 12 Mansfield Road, OX1 3TA Oxford, UK.

[(18)F]FMTEB, [(18)F]FPEB, [(18)F]flumazenil, [(18)F]DAA1106, [(18)F]MFBG, [(18)F]FDOPA, [(18)F]FMT and [(18)F]FDA are prepared from the corresponding arylboronic esters and [(18)F]KF/K222 in the presence of Cu(OTf)2py4. The method was successfully applied using three radiosynthetic platforms, and up to 26 GBq of non-carrier added starting activity of (18)F-fluoride.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c6cc03295hDOI Listing
June 2016

Nevus count associations with pigmentary phenotype, histopathological melanoma characteristics and survival from melanoma.

Int J Cancer 2016 09 30;139(6):1217-22. Epub 2016 May 30.

Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL.

Although nevus count is an established risk factor for melanoma, relationships between nevus number and patient and tumor characteristics have not been well studied and the influence of nevus count on melanoma-specific survival is equivocal. Using data from the Genes, Environment and Melanoma (GEM) study, a large population-based study of primary cutaneous melanoma, we evaluated associations between number of nevi and patient features, including sun-sensitivity summarized in a phenotypic index, and tumor characteristics. We also assessed the association of nevus count with melanoma-specific survival. Higher nevus counts were independently and positively associated with male gender and younger age at diagnosis, and they were inversely associated with lentigo maligna histology. We observed a borderline significant trend of poorer melanoma-specific survival with increasing quartile of nevus count, but little or no association between number of nevi and pigmentary phenotypic characteristics or prognostic tumor features.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ijc.30157DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4939099PMC
September 2016

Neutrophil Toll-Like Receptor 9 Expression and the Systemic Inflammatory Response in Acetaminophen-Induced Acute Liver Failure.

Crit Care Med 2016 Jan;44(1):43-53

1Institute of Liver Studies and Transplantation, King's College London School of Medicine at King's College Hospital, London, United Kingdom.2Liver Intensive Care Unit, King's College London School of Medicine at King's College Hospital, London, United Kingdom.3Foundation for Liver Research, London, United Kingdom.4Hepatology and Gastroenterology, Liver and Antiviral Unit, St. Marys Hospital, Imperial College London, London, United Kingdom.

Objectives: There is a marked propensity for patients with acetaminophen-induced acute liver failure to develop sepsis, which may culminate in multiple organ failure and death. Toll-like receptors sense pathogens and induce inflammatory responses, but whether this is protective or detrimental in acetaminophen-induced acute liver failure remains unknown.

Design, Setting, And Patients: We assessed Toll-like receptor expression on circulating neutrophils and their function in 24 patients with acetaminophen-induced acute liver failure and compared with 10 healthy controls.

Interventions: Neutrophil Toll-like receptor 2, -4, and -9 expression and cytokine production and function were studied ex vivo at baseline and following stimulation with lipopolysaccharide, oligodeoxynucleotides, ammonium chloride, and interleukin-8. To examine the influence of acetaminophen-induced acute liver failure plasma and endogenous DNA on Toll-like receptors-9 expression, healthy neutrophils were incubated with acetaminophen-induced acute liver failure plasma with and without deoxyribonuclease-I.

Measurements And Main Results: Circulating neutrophil Toll-like receptor 9 expression was increased in acetaminophen-induced acute liver failure on day 1 compared with healthy controls (p = 0.0002), whereas Toll-like receptor 4 expression was decreased compared with healthy controls (p < 0.0001). Toll-like receptor 2 expression was unchanged. Neutrophil phagocytic activity was decreased, and spontaneous oxidative burst increased in all patients with acetaminophen-induced acute liver failure compared with healthy controls (p < 0.0001). Neutrophil Toll-like receptor 9 expression correlated with plasma interleukin-8 and peak ammonia concentration (r = 0.6; p < 0.05) and increased with severity of hepatic encephalopathy (grade 0-2 vs 3/4) and systemic inflammatory response syndrome score (0-1 vs 2-4) (p < 0.05). Those patients with advanced hepatic encephalopathy (grade 3/4) or high systemic inflammatory response syndrome score (2-4) on day 1 had higher neutrophil Toll-like receptor 9 expression, arterial ammonia concentration, and plasma interleukin-8 associated with neutrophil exhaustion. Healthy neutrophil Toll-like receptor 9 expression increased upon stimulation with acetaminophen-induced acute liver failure plasma, which was abrogated by preincubation with deoxyribonuclease-I. Intracellular Toll-like receptor 9 was induced by costimulation with interleukin-8 and ammonia.

Conclusion: These data point to neutrophil Toll-like receptor 9 expression in acetaminophen-induced acute liver failure being mediated both by circulating endogenous DNA as well as ammonia and interleukin-8 in a synergistic manner inducing systemic inflammation, neutrophil exhaustion, and exacerbating hepatic encephalopathy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/CCM.0000000000001309DOI Listing
January 2016

Rational Manual and Automated Scoring Thresholds for the Immunohistochemical Detection of TP53 Missense Mutations in Human Breast Carcinomas.

Appl Immunohistochem Mol Morphol 2016 Jul;24(6):398-404

*Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL †Translational Pathology Laboratory, School of Medicine ‡Lineberger Comprehensive Cancer Center §Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill ∥Department of Pathology, Duke University School of Medicine, Durham, NC.

Missense mutations in TP53 are common in human breast cancer, have been associated with worse prognosis, and may predict therapy effect. TP53 missense mutations are associated with aberrant accumulation of p53 protein in tumor cell nuclei. Previous studies have used relatively arbitrary cutoffs to characterize breast tumors as positive for p53 staining by immunohistochemical assays. This study aimed to objectively determine optimal thresholds for p53 positivity by manual and automated scoring methods using whole tissue sections from the Carolina Breast Cancer Study. p53-immunostained slides were available for 564 breast tumors previously assayed for TP53 mutations. Average nuclear p53 staining intensity was manually scored as negative, borderline, weak, moderate, or strong and percentage of positive tumor cells was estimated. Automated p53 signal intensity was measured using the Aperio nuclear v9 algorithm combined with the Genie histology pattern recognition tool and tuned to achieve optimal nuclear segmentation. Receiver operating characteristic curve analysis was performed to determine optimal cutoffs for average staining intensity and percent cells positive to distinguish between tumors with and without a missense mutation. Receiver operating characteristic curve analysis demonstrated a threshold of moderate average nuclear staining intensity as a good surrogate for TP53 missense mutations in both manual (area under the curve=0.87) and automated (area under the curve=0.84) scoring systems. Both manual and automated immunohistochemical scoring methods predicted missense mutations in breast carcinomas with high accuracy. Validation of the automated intensity scoring threshold suggests a role for such algorithms in detecting TP53 missense mutations in high throughput studies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/PAI.0000000000000207DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4716889PMC
July 2016

Inherited variation at MC1R and histological characteristics of primary melanoma.

PLoS One 2015 19;10(3):e0119920. Epub 2015 Mar 19.

Department of Cancer Epidemiology, Moffitt Cancer Center, Tampa, Florida, United States of America.

Variation in the melanocortin-1receptor (MC1R) gene is associated with pigmentary phenotypes and risk of malignant melanoma. Few studies have reported on MC1R variation with respect to tumor characteristics, especially clinically important prognostic features. We examined associations between MC1R variants and histopathological melanoma characteristics. Study participants were enrolled from nine geographic regions in Australia, Canada, Italy and the United States and were genotyped for MC1R variants classified as high-risk [R] (D84E, R142H, R151C, R160W, and D294H, all nonsense and insertion/deletion) or low-risk [r] (all other nonsynonymous) variants. Tissue was available for 2,160 white participants of the Genes, Environment and Melanoma (GEM) Study with a first incident primary melanoma diagnosis, and underwent centralized pathologic review. No statistically significant associations were observed between MC1R variants and AJCC established prognostic tumor characteristics: Breslow thickness, presence of mitoses or presence of ulceration. However, MC1R was significantly associated with anatomic site of melanoma (p = 0.002) and a positive association was observed between carriage of more than one [R] variant and melanomas arising on the arms (OR = 2.39; 95% CI: 1.40, 4.09). We also observed statistically significant differences between sun-sensitive and sun-resistant individuals with respect to associations between MC1R genotype and AJCC prognostic tumor characteristics. Our results suggest inherited variation in MC1R may play an influential role in anatomic site presentation of melanomas and may differ with respect to skin pigmentation phenotype.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0119920PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4366050PMC
February 2016

Inherited variation at MC1R and ASIP and association with melanoma-specific survival.

Int J Cancer 2015 Jun 26;136(11):2659-67. Epub 2014 Nov 26.

Department of Cancer Epidemiology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL.

Melanocortin-1 receptor (MC1R) is a marker of melanoma risk in populations of European ancestry. However, MC1R effects on survival are much less studied. We investigated associations between variation at MC1R and survival in an international, population-based series of single primary melanoma patients enrolled into the Genes, Environment, and Melanoma study. MC1R genotype data was available for 2,200 participants with a first incident primary melanoma diagnosis. We estimated the association of MC1R genotypes with melanoma-specific survival (i.e., death caused by melanoma) and overall survival using COX proportional hazards modeling, adjusting for established prognostic factors for melanoma. We also conducted stratified analyses by Breslow thickness, tumor site, phenotypic index, and age. In addition, we evaluated haplotypes involving polymorphisms near the Agouti signaling protein gene (ASIP) locus for their impacts on survival. Melanoma-specific survival was inversely associated with carriage of MC1R variants in the absence of consensus alleles compared to carriage of at least one consensus allele (hazard ratio (HR) = 0.60; 95% confidence interval (CI): 0.40, 0.90). MC1R results for overall survival were consistent with no association. We did not observe any statistical evidence of heterogeneity of effect estimates in stratified analyses. We observed increased hazard of melanoma-specific death among carriers of the risk haplotype TG near the ASIP locus (HR = 1.37; 95% CI: 0.91, 2.04) when compared to carriers of the most common GG haplotype. Similar results were noted for overall survival. Upon examining the ASIP TG/TG diplotype, we observed considerably increased hazard of melanoma-specific death (HR = 5.11; 95% CI: 1.88, 13.88) compared to carriers of the most common GG/GG diplotype. Our data suggest improved melanoma-specific survival among carriers of two inherited MC1R variants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ijc.29317DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4361274PMC
June 2015

Genetic variation in cell cycle regulatory gene AURKA and association with intrinsic breast cancer subtype.

Mol Carcinog 2015 Dec 18;54(12):1668-77. Epub 2014 Oct 18.

Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina.

AURKA is a putative low-penetrance tumor susceptibility gene due to its prominent role in cell cycle regulation and centrosomal function. Germline variation in AURKA was evaluated for association with breast cancer and intrinsic breast cancer subtypes in the Carolina Breast Cancer Study (CBCS), a population-based case-control study of African Americans (AA) and Caucasians (Cau). Tag and candidate single nucleotide polymorphisms (SNPs) on AURKA were genotyped in 1946 cases and 1747 controls. In race-stratified analyses adjusted for age and African ancestry, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate SNP associations with breast cancer. In a race-combined analysis with similar adjustment, these associations were also examined by intrinsic breast cancer subtype. Using dominant models, most AURKA SNPs demonstrated no association with breast cancer in the race-stratified analyses. Among AA, rs6092309 showed an inverse association with breast cancer (OR = 0.69, 95% CI = 0.53-0.90). In the race-combined analyses, rs6099128 had reduced ORs for luminal A (OR = 0.76, 95% CI = 0.60-0.95) and basal-like breast cancer (OR = 0.54, 95% CI = 0.37-0.80). Rs6092309 showed a similar pattern of association with each subtype. Three SNPs (rs6014711, rs911162, rs1047972) had positive associations with basal-like breast cancer, and ORs reduced or close to 1.00 for other subtypes. Our results suggest inverse associations between some AURKA SNPs and overall breast cancer in AA. We found differential associations by specific subtypes and by race. Replication of these findings in larger AA populations would allow more powerful race-stratified subtype analyses.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mc.22238DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4402110PMC
December 2015

A general copper-mediated nucleophilic 18F fluorination of arenes.

Angew Chem Int Ed Engl 2014 Jul 10;53(30):7751-5. Epub 2014 Jun 10.

Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA (UK).

Molecules labeled with fluorine-18 are used as radiotracers for positron emission tomography. An important challenge is the labeling of arenes not amenable to aromatic nucleophilic substitution (SNAr) with [(18)F]F(-). In the ideal case, the (18)F fluorination of these substrates would be performed through reaction of [(18)F]KF with shelf-stable readily available precursors using a broadly applicable method suitable for automation. Herein, we describe the realization of these requirements with the production of (18)F arenes from pinacol-derived aryl boronic esters (arylBPin) upon treatment with [(18)F]KF/K222 and [Cu(OTf)2(py)4] (OTf = trifluoromethanesulfonate, py = pyridine). This method tolerates electron-poor and electron-rich arenes and various functional groups, and allows access to 6-[(18)F]fluoro-L-DOPA, 6-[(18)F]fluoro-m-tyrosine, and the translocator protein (TSPO) PET ligand [(18)F]DAA1106.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/anie.201404436DOI Listing
July 2014

Catalytic decarboxylative alkenylation of enolates.

Org Lett 2013 Jul 8;15(14):3778-81. Epub 2013 Jul 8.

Department of Chemistry, University of York, Heslington, York YO10 5DD, UK.

A palladium-catalyzed decarboxylative alkenylation of stabilized enolates has been developed, which gives rise to alkenylated dicarbonyl products from enol carbonates regioselectively with concomitant installation of a quaternary all-carbon center. The broad scope of the reaction has been demonstrated by successfully utilizing a range of enolates and external phenol nucleophiles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ol401729mDOI Listing
July 2013

Alcohol dehydrogenase-specific T-cell responses are associated with alcohol consumption in patients with alcohol-related cirrhosis.

Hepatology 2013 Jul 27;58(1):314-24. Epub 2013 May 27.

Institute of Liver Studies, School of Medicine at King's College Hospital, King's College London, London, United Kingdom.

Unlabelled: Patients with alcohol-related liver disease (ALD) have antibodies directed to alcohol dehydrogenase (ADH), anti-ADH titers being associated with disease severity and active alcohol consumption. ADH-specific T-cell responses have not been characterized. We aimed to define anti-ADH cellular immune responses and their association with active alcohol consumption and disease severity. Using cultures of peripheral blood mononuclear cells (PBMCs) from 25 patients with alcohol-related cirrhosis (ARC; 12 were actively drinking or abstinent for <6 months, and 13 were abstinent for >6 months) and hepatic mononuclear cells (HMCs) from 14 patients with ARC who were undergoing transplantation, we investigated T-cell reactivity to 25 overlapping peptides representing the full human ADH protein (beta 1 subunit). ADH-specific peripheral T-cell responses were assessed by the quantification of T-cell proliferation and cytokine production and were correlated with the clinical course. In active alcohol consumers, proliferative T-cell responses targeted ADH31-95 and other discontinuous sequences in the ADH peptide, whereas only one sequence was targeted in abstinents. ADH peptides induced the production of interferon-γ (IFN-γ), interleukin-4 (IL-4), and IL-17. IL-4 production was lower in active drinkers versus abstinents, and IL-17 production was higher. Peptides inducing IFN-γ production outnumbered those inducing T-cell proliferation. The intensity of the predominantly T helper 1 (Th 1) responses directly correlated with disease severity. Similar to PBMCs in abstinents, ADH peptides induced weak T-cell proliferation and a similar level of IL-4 production in HMCs but less vigorous Th 1 and T helper 17 responses.

Conclusion: This suggests that Th 1 responses to ADH in ARC are induced by alcohol consumption. A Th 1/T helper 2 imbalance characterizes T-cell responses in active drinkers with ARC, whereas IL-4 production prevails in abstinents. This identifies new targets for immunoregulatory therapies in ALD patients for halting detrimental effector T-cell responses, which may encourage liver fibrogenesis and progression to end-stage liver disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep.26334DOI Listing
July 2013

Circulating neutrophil dysfunction in acute liver failure.

Hepatology 2013 Mar 12;57(3):1142-52. Epub 2012 Dec 12.

Liver Intensive Care Unit and Transplantation, King's College London School of Medicine at King's College Hospital, London, UK; Institute of Liver Studies and Transplantation, King's College London School of Medicine at King's College Hospital, London, UK.

Unlabelled: Systemic inflammation and susceptibility to developing sepsis is common in acute liver failure (ALF) resulting in tissue damage and organ failure. This study characterized the function of circulating neutrophils in 25 patients with ALF and subacute liver failure (SALF). ALF (n=15)/SALF (n=10) patients were prospectively studied and compared with 11 healthy (HC) and 6 septic controls (SC). Neutrophils were isolated on admission to intensive care and every 3-4 days until death / liver transplantation / recovery. Neutrophil phenotype was determined using fluorochrome-labeled antibodies to CD16 and CD11b and assessed by flow cytometry. Neutrophil phagocytic activity (NPA) was determined using fluorescein isothiocyanate-labeled opsonized Escherichia coli and oxidative burst (OB) was determined by the percentage of neutrophils producing reactive oxygen species (ROS) at rest and after stimulation with opsonized E. coli. Physiological variables, biochemistry, arterial ammonia, microbiology, and outcomes were collected. Plasma pro- and antiinflammatory cytokine profiles were performed by enzyme-linked immunosorbent assay. Neutrophil expression of CD16 which recognizes the FcγRIII region of immunoglobulin G was significantly reduced in the ALF cohort (P<0.001) on day 1 compared to HC. NPA was significantly impaired in the SALF cohort compared to HC (P<0.01). Impaired NPA in the ALF and SALF cohorts on admission predicted nonsurvival without liver transplantation (P=0.01). Spontaneous neutrophil production of ROS was not significantly increased in any of the cohorts. E. coli-stimulated OB was preserved in ALF/SALF cohorts but was significantly impaired in the SC group (P<0.05).

Conclusion: Circulating neutrophils in ALF/SALF have impaired bacteriocidal function similar to that seen in severe sepsis. Neutrophil function indices are important biomarkers in ALF and may be implicated in the development of organ dysfunction and the increased susceptibility to developing sepsis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep.26102DOI Listing
March 2013

Neurofilaments are flexible polymers that often fold and unfold, but they move in a fully extended configuration.

Cytoskeleton (Hoboken) 2012 Jul 12;69(7):535-44. Epub 2012 Jun 12.

Department of Neuroscience, Wexner Medical Center, Ohio State University, Columbus, Ohio 43210, USA.

Time-lapse imaging of neurofilaments in axons of cultured nerve cells has demonstrated that these cytoskeletal polymers move along microtubule tracks in both anterograde and retrograde directions, powered by microtubule motors. The filaments exhibit short bouts of rapid intermittent movement interrupted by prolonged pauses, and the average velocity is slow because they spend most of their time pausing. Here, we show that axonal neurofilaments are also very flexible and frequently exhibit complex and dynamic folding and unfolding behaviors while they are pausing. Remarkably, however, when the filaments move in a sustained manner, we find that they always adopt an unfolded, that is, fully extended configuration, and this applies to movement in both anterograde and retrograde directions. Given the flexibility of neurofilament polymers and the apparent ease with which they can fold back on themselves, the fact that they move in a fully extended configuration suggests that moving neurofilaments may be pulled from their leading end. Thus, we speculate that motors may bind to the leading ends of neurofilaments polymers during both anterograde and retrograde motion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cm.21039DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3415975PMC
July 2012

The impact of organ dysfunction in cirrhosis: survival at a cost?

J Hepatol 2012 May 13;56(5):1054-1062. Epub 2012 Jan 13.

Liver Intensive Care Unit and Institute of Liver Studies and Transplantation, King's College London School of Medicine at King's College Hospital, Denmark Hill, London SE5 9RS, UK. Electronic address:

Background & Aims: The incidence of cirrhosis and subsequent development of organ dysfunction (OD) requiring intensive care unit (ICU) support is rising. Historically, critically ill cirrhotics are perceived as having poor prognosis and substantial cost of care.

Methods: The aim was to prospectively analyse resource utilisation and cost of a large cohort of patients (n=660) admitted to a Liver ICU from 2000 to 2007 with cirrhosis and OD. Child Pugh, MELD, SOFA, APACHE II, and organ support requirements were collected. The Therapeutic Intervention Scoring System (TISS) score, a validated tool for estimating cost in ICU, was calculated daily. Logistic regression was used to determine independent predictors of increased cost.

Results: Alcohol was the most common etiology (47%) and variceal bleeding (VB) the most common reason for admission (35%). Invasive ventilatory support was required in 74% of cases, vasopressors in 49%, and 50% required renal replacement therapy. Forty-nine per cent of non-transplanted patients survived to ICU discharge. Median TISS score and ICU cost per patient were 261 and €14,139, respectively. VB patients had the highest survival rates (53% vs. 24%; p<0.001) and lower associated cost. A combination of VB (OR 0.48), need for ventilation (OR 2.81), low PO(2)/FiO(2) on admission (OR 0.97), and lactate (OR 0.93) improved cost prediction on multivariate analysis (AUROC 0.7; p<0.001) but organ failure scores per se were poor predictors of cost.

Conclusions: Patients with cirrhosis and OD result in considerable resource expenditure but have acceptable hospital survival. Further health economic assessment and outcome prediction tools are required to appropriately target resource utilisation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhep.2011.12.014DOI Listing
May 2012

The quest for the elusive factors that underpin neutrophil dysfunction in cirrhosis goes on.

J Hepatol 2012 May 27;56(5):1212-1213. Epub 2011 Nov 27.

Institute of Liver Studies and Transplantation, King's College London School of Medicine at King's College Hospital, Denmark Hill, London SE5 9RS, UK. Electronic address:

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jhep.2011.10.013DOI Listing
May 2012

Intermittent subglottic secretion drainage and ventilator-associated pneumonia.

Am J Respir Crit Care Med 2011 May;183(10):1435-6; author reply 1436-7

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1164/ajrccm.183.10.1435aDOI Listing
May 2011

Alpha1-antitrypsin deficiency.

N Engl J Med 2009 Nov;361(21):2102; author reply 2102

View Article and Find Full Text PDF

Download full-text PDF

Source
November 2009

Ammonia and the neutrophil in the pathogenesis of hepatic encephalopathy in cirrhosis.

Hepatology 2010 Mar;51(3):1062-9

Institute of Liver Studies, King's College London School of Medicine at King's College Hospital, 3rd Floor Cheyne Wing, King's College Hospital, Denmark Hill, London SE5 9RS, UK.

Hepatic encephalopathy (HE) constitutes a neuropsychiatric syndrome which remains a major clinical problem in patients with cirrhosis. In the severest form of HE, cirrhotic patients may develop varying degrees of confusion and coma. Ammonia has been regarded as the key precipitating factor in HE, and astrocytes have been the most commonly affected cells neuropathologically. Although the evidence base supporting a pivotal role of ammonia is robust, in everyday clinical practice a consistent correlation between the concentration of ammonia in the blood and the manifest symptoms of HE is not observed. More recently the synergistic role of inflammation and infection in modulating the cerebral effects of ammonia has been shown to be important. Furthermore, it has been recognized that infection impairs brain function both in the presence and absence of liver disease. Thus it could be postulated that in the presence of ammonia, the brain is sensitized to a systemic inflammatory stimulus and is able to elicit an inflammatory response involving both proinflammatory and neurotransmitter pathways. Ammonia is not only directly toxic to astrocytes but induces neutrophil dysfunction with the release of reactive oxygen species, which contribute to oxidative stress and systemic inflammation. This may further exacerbate the cerebral effects of ammonia and potentially reduce the capacity of the neutrophil to fight microbial attack, thus inducing a vicious circle. This evidence supports the neutrophil in addition to ammonia as being culpable in the pathogenesis of HE, making the neutrophil a target for future anti-inflammatory therapeutic strategies in addition to ammonia lowering therapies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/hep.23367DOI Listing
March 2010

Pentacyclic furanosteroids: the synthesis of potential kinase inhibitors related to viridin and wortmannolone.

J Org Chem 2009 Aug;74(15):5429-39

Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

A regiocontrolled intermolecular Diels-Alder reaction of an o-benzoquinone followed by an intramolecular nitrile oxide cyclization is employed to prepare the BCD fragment of viridin. The AE segment is attached to it by means of an intramolecular Diels-Alder reaction of an o-benzoquinone monoketal generated in situ from tricycle 15 and 5-trimethylsilyl-2E,4E-pentadienol 20. The silyl substituent at C-1 of the pentacyclic product directs the dihydroxylation of the C2-C3 double bond to its beta-face. Various transformations of the 1alpha-trimethylsilyl-2beta,3beta-dihydroxy pentacycle into several others with oxygen substituents in ring A are described. One of these products 40 possesses the same structure and relative stereochemistry in rings A, B, and E as that of the natural product wortmannolone 3.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jo900922qDOI Listing
August 2009

Cyclobutanone mimics of penicillins: effects of substitution on conformation and hemiketal stability.

J Org Chem 2008 Sep 19;73(18):6970-82. Epub 2008 Aug 19.

Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.

The tendency for carbocyclic analogues of penicillins to undergo hydrate and hemiketal formation is central to their ability to function as beta-lactamase inhibitors. 2-Thiabicyclo[3.2.0]heptan-6-one-4-carboxylates with alkoxy functionality at C3 have been prepared through two complementary diastereoselective substitution reactions following a highly stereoselective chlorination with sulfuryl chloride. We have found that carbocyclic analogues with 3beta substituents favor an endo envelope conformation in solution, the solid state, and the gas phase, whereas those with 3alpha substituents adopt an exo envelope. Evidence from X-ray crystal structures and ab initio calculations suggests that an anomeric effect contributes to the large conformational preference of the tetrahydrothiophene ring that favors the C3 substituent in an axial orientation. In addition, the envelope conformation of the bicycle, which is determined by the stereochemistry of the C3 substituent, has a dramatic effect on the ability of the cyclobutanone to undergo hemiketal formation in methanol-d4.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jo801274mDOI Listing
September 2008

A biogenetically-inspired synthesis of a ring-D model of kinamycin F: insights into the conformation of ring D.

Org Lett 2008 Feb 10;10(3):381-4. Epub 2008 Jan 10.

Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

An efficient three-step construction of the highly oxygenated D-ring of the kinamycin antibiotics is reported for a simple model system. A comparison of the spectroscopic characteristics of the synthetic models with those of natural kinamycin F, which is suspected to be the bioactive form of the kinamycins, leads to the conclusion that the favored D-ring conformation of kinamycin F differs from that of the other partially or fully acylated variants.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ol702650uDOI Listing
February 2008

Total synthesis of isoprekinamycin: structural evidence for enhanced diazonium ion character and growth inhibitory activity toward cancer cells.

Org Lett 2007 Jul 22;9(15):2915-8. Epub 2007 Jun 22.

Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada.

The structurally novel diazobenzo[a]fluorene antibiotic isoprekinamycin (IPK) has been synthesized for the first time employing a Suzuki coupling of a brominated AB ring synthon with a boronate ester representing the D ring, followed by anionic cyclization and appropriate functional group manipulations. The first indication that the diazobenzo[a]fluorene system exhibits in vitro anticancer activity is provided and X-ray crystallographic evidence for enhancement of diazonium ion character as a consequence of intramolecular H-bonding is described.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ol0712374DOI Listing
July 2007

Ruthenium(II) complexes with improved photophysical properties based on planar 4'-(2-pyrimidinyl)-2,2':6',2' '-terpyridine ligands.

Inorg Chem 2007 Apr 16;46(7):2854-63. Epub 2007 Feb 16.

Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1, Département de Chimie, Université de Montréal, Canada.

A series of new tridentate polypyridine ligands, made of terpyridine chelating subunits connected to various substituted 2-pyrimidinyl groups, and their homoleptic and heteroleptic Ru(II) complexes have been prepared and characterized. The new metal complexes have general formulas [(R-pm-tpy)Ru(tpy)]2+ and [Ru(tpy-pm-R)2]2+ (tpy = 2,2':6',2' '-terpyridine; R-pm-tpy = 4'-(2-pyrimidinyl)-2,2':6',2' '-terpyridine with R = H, methyl, phenyl, perfluorophenyl, chloride, and cyanide). Two of the new metal complexes have also been characterized by X-ray analysis. In all the R-pm-tpy ligands, the pyrimidinyl and terpyridyl groups are coplanar, allowing an extended delocalization of acceptor orbital of the metal-to-ligand charge-transfer (MLCT) excited state. The absorption spectra, redox behavior, and luminescence properties of the new Ru(II) complexes have been investigated. In particular, the photophysical properties of these species are significantly better compared to those of [Ru(tpy)2]2+ and well comparable with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical properties lie at the same time in an enhanced MLCT-MC (MC = metal centered) energy gap and in a reduced difference between the minima of the excited and ground states potential energy surfaces. The enhanced MLCT-MC energy gap leads to diminished efficiency of the thermally activated pathway for the radiationless process, whereas the similarity in ground and excited-state geometries causes reduced Franck Condon factors for the direct radiationless decay from the MLCT state to the ground state of the new complexes in comparison with [Ru(tpy)2]2+ and similar species.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ic0622609DOI Listing
April 2007
-->