A184 REPURPOSING DRUGS FOR SPLEEN TYROSINE KINASE (SYK) PEDIATRIC PATIENTS USING HIGH-THROUGHPUT SCREENING

Background

Spleen Tyrosine Kinase (SYK) is a cytosolic, non-receptor tyrosine kinase with an imperative role in immune and non-immune processes. Recently, we identified six gain-of-function SYK variants in patients that presented multi-organ inflammation and immune dysregulation. The SYK variants displayed constitutive SYK phosphorylation in human embryonic kidney (HEK) 293T, colonic epithelial cells (SW480), and in knock-in heterozygous SYK mice. These observations mark SYK as a therapeutic target for autoimmune diseases.

Phenotype drug discovery accelerates this process and can be done successfully with an appropriate phenotype. A possible phenotype displayed by SYK variants is SYK phosphorylation, as high-throughput screening can identify hit compounds that reduce the constitutive activation of phosphorylated SYK (p-SYK).

Aims

Aim 1: Determine the screening phenotype with wildtype (WT) and SYK S550Y variant in HEK293T cells. Recently, we observed increased phosphorylation in gain-of-function SYK variants We hypothesize that we can use phosphorylated-SYK (p-SYK) levels to identify hit compounds that can decrease the kinase activity in these variants. With stable transfected SYK WT and SYK S550Y HEK293T cell-line, protein analyses will be completed to characterize the appropriate screening phenotype.

Aim 2

Establish an assay for high-throughput drug screening. We will utilize homogenous time-resolved fluorescence (HTRF) assay. The signal measured from HTRF is positively proportional to the level of p-SYK; therefore, we expect that S550Y cells will have a higher signal than the WT.

Aim 3

Validate hit compounds in HEK293T and zebrafish. We will create a dose-response curve with the hit compounds in in vitro and in vivo models.

Methods

We will use stable transfection to established overexpressing SYK WT and S550Y HEK293T cells. We will apply homogenous time-resolved fluorescence (HTRF) to quantify p-SYK levels during the drug screening.

Results

Protein analyses have verified high expression of p-SYK in stable transfected HEK293T cells. No stimulation was required, as the cells showed an increased phosphorylation level at baseline. Downstream signaling partners such as p-ERK and p-JNK of the MAPK pathway displayed an upregulation. This suggests that the sustained activation of p-SYK may consequently affect cellular processes and contribute to the clinical manifestations observed in patients.

Conclusions

This research study will identify hit compounds that can produce a safe and effective biological response in pediatric patients with gain-of-function SYK variants. Personalizing medicine throughout high-throughput drug screening can accelerate drug repurposing for pediatric patients with multiple systemic diseases and immune dysregulation.

Funding Agencies

None

A26 A SYSTEMTIC REVIEW OF MONOGENIC INFLAMMATORY BOWEL DISEASE: CLINICAL PHENOTYPE AND GENOTYPE

Background

Advances in genomic technologies have led to an increase in reports of monogenic inflammatory bowel disease (IBD). The majority of the studies on monogenic IBD have focused only on young children aged <6 years. There are no detailed reports containing a comprehensive picture of monogenic IBD with specific numbers on the clinical features, genetic profiles and disease course. Since each gene-specific cause of monogenic IBD is rare, it is difficult to collect cases in a single study even with international cohort studies.

Aims

To elucidate a comprehensive picture of monogenic IBD, we conducted a systematic review of all reported cases of monogenic IBD.

Methods

A systematic review of MEDLINE articles published between January 2000 and December 2019 was conducted. 662 monogenic IBD cases were identified from 273 eligible articles. Data on clinical manifestation, genotype, and management were collected.

Results

The most frequently reported genes causative of monogenic IBD patients were IL10RA, CYBB, IL10RB, and TTC7A (Figure). In total, 64.8% of patients developed IBD before six years old, 15.6% between ages 10 and 17.9 years, and 11.6% at age 18 years or older. Only 32.7% had any history of extra-intestinal manifestation (EIM) before IBD onset. There was substantial difference in the onset age groups and the underlying monogenic disorders. 74.4% developed at least one EIM during their clinical course. The most common EIMs were atypical infection (44.1%), dermatologic abnormality (39.2%), autoimmunity (22.7%) and lymphoid organ abnormality (11.5%). Autosomal recessive (62.8%) was the most common inheritance pattern, and missense-variants (44.3%) were the most identified type of genetic variants. Deletions including CNVs, intronic, synonymous and inversion, which have the possibility to be overlooked by whole exome sequencing were shown in some cases. Bowel surgery, biologics, and hematopoietic stem cell transplantation were performed in 28.3%, 32.8%, and 24.4% of patients, respectively.

Conclusions

Monogenic IBD diagnosis and management is a challenging clinical problem across age groups; the EIMs are more diverse and the management is evidently more difficult compared to non-monogenic IBD. An improved understanding of the characteristics of the genes and underlying disease processes in monogenic IBD is necessary for effective management.

Funding Agencies

CAG, CIHRUehara Memorial Foundation Fellowship

A167 UNDERSTANDING THE IMPACT OF DOWNSTREAM OF KINASE 4 (DOK4) DAMAGING GENETIC VARIANTS IN THE PATHOGENESIS OF PEDIATRIC INFLAMMATORY BOWEL DISEASE (IBD)

Background

IBD is a chronic inflammatory disorder of the gastrointestinal (GI) tract whose precise pathological mechanisms remain elusive. It is thought that in pediatric IBD, pathogenic exposure does not appear sufficient to cause disease, thus genetic variations are critical to disease pathogenesis. The Muise Lab uses genetic sequencing of patients with IBD from all over the world to identify crucial genetic variations that are critical to IBD development.

We report two patients with IBD from unrelated families with mutations in DOK4. Both patients had profound extra-intestinal disease complicating their IBD.

Downstream of kinase (DOK) proteins are a family of adaptor molecules that are important in regulating cell signaling, especially in immune cells. They are known to suppress MAPK and PI3K/AKT pathways, whose dysregulation result in cancer. DOK4 has not been extensively studied, but research suggests that this gene produces two isoforms. It is known to have negative regulatory effects on immune cell activation but is also expressed across various other tissues, where its function is yet to be determined.

Aims

We hypothesize that these variations in DOK4 lead to immune cell dysregulation, which manifests in both gastrointestinal and systemic chronic inflammatory disease. Through this study, we aim to elucidate the mechanism of novel genetic defects in DOK4.

Methods

It will be critical to understand how variants within both patients are contributing to the onset of IBD through in vitro studies. Therefore, we will characterize and quantify how changes in expression of DOK4 alters essential cell signaling pathways. We have established immortalized cell lines from patients bearing these mutations to specifically characterize potential immune defects. We will also be using knock out cell models to understand the effect of loss of function of DOK4 in different cell types.

Results

Preliminary data shows variation in expression of the protein within patient peripheral blood mononuclear cells (PBMCs) compared to a healthy donor. Overexpression in HEK293T cells shows changes in MAPK and NFkB signaling.

Conclusions

With this study, we hope to identify new therapeutic targets for patients with DOK4 mutations.

Funding Agencies

CIHRThe Leona M. and Harry B. Helmsley Charitable Trust

Assessment of InSight Landing Site Predictions

Comprehensive analysis of remote sensing data used to select the Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) landing site correctly predicted the atmospheric temperature and pressure profile during entry and descent, the safe landing surface, and the geologic setting of the site. The smooth plains upon which the InSight landing site is located were accurately predicted to be generally similar to the Mars Exploration Rover Spirit landing site with relatively low rock abundance, low slopes, and a moderately dusty surface with a 3-10 m impact fragmented regolith over Hesperian to Early Amazonian basaltic lava flows. The deceleration profile and surface pressure encountered by the spacecraft during entry, descent, and landing compared well (within 1σ) of the envelope of modeled temperature profiles and the expected surface pressure. Orbital estimates of thermal inertia are similar to surface radiometer measurements, and materials at the surface are dominated by poorly consolidated sand as expected. Thin coatings of bright atmospheric dust on the surface were as indicated by orbital albedo and dust cover index measurements. Orbital estimates of rock abundance from shadow measurements in high-resolution images and thermal differencing indicated very low rock abundance and surface counts show 1-4% area covered by rocks. Slopes at 100 to 5 m length scale measured from orbital topographic and radar data correctly indicated a surface comparably smooth and flat as the two smoothest landing sites (Opportunity and Phoenix). Thermal inertia and radar data indicated the surface would be load bearing as found.

Advanced MRI of Liver Fibrosis and Treatment Response in a Rat Model of Nonalcoholic Steatohepatitis

Background Liver biopsy is the reference standard to diagnose nonalcoholic steatohepatitis (NASH) but is invasive with potential complications. Purpose To evaluate molecular MRI with type 1 collagen-specific probe EP-3533 and allysine-targeted fibrogenesis probe Gd-Hyd, MR elastography, and native T1 to characterize fibrosis and to assess treatment response in a rat model of NASH. Materials and Methods MRI was performed prospectively (June-November 2018) in six groups of male Wistar rats (a) age- and (b) weight-matched animals received standard chow (n = 12 per group); (c) received choline-deficient, l-amino acid-defined, high-fat diet (CDAHFD) for 6 weeks or (d) 9 weeks (n = 8 per group); (e) were fed 6 weeks of CDAHFD and switched to standard chow for 3 weeks (n = 12); (f) were fed CDAHFD for 9 weeks with daily treatment of elafibranor beginning at week 6 (n = 14). Differences in imaging measurements and tissue analyses among groups were tested with one-way analysis of variance. The ability of each imaging measurement to stage fibrosis was quantified by using area under the receiver operating characteristic curve (AUC) with quantitative digital pathology (collagen proportionate area [CPA]) as reference standard. Optimal cutoff values for distinguishing advanced fibrosis were used to assess treatment response. Results AUC for distinguishing fibrotic (CPA >4.8%) from nonfibrotic (CPA ≤4.8%) livers was 0.95 (95% confidence interval [CI]: 0.91, 1.00) for EP-3533, followed by native T1, Gd-Hyd, and MR elastography with AUCs of 0.90 (95% CI: 0.83, 0.98), 0.84 (95% CI: 0.74, 0.95), and 0.65 (95% CI: 0.51, 0.79), respectively. AUCs for discriminating advanced fibrosis (CPA >10.3%) were 0.86 (95% CI: 0.76, 0.97), 0.96 (95% CI: 0.90, 1.01), 0.84 (95% CI: 0.70, 0.98), and 0.74 (95% CI: 0.63, 0.86) for EP-3533, Gd-Hyd, MR elastography, and native T1, respectively. Gd-Hyd MRI had the highest accuracy (24 of 26, 92%; 95% CI: 75%, 99%) in identifying responders and nonresponders in the treated groups compared with MR elastography (23 of 26, 88%; 95% CI: 70%, 98%), EP-3533 (20 of 26, 77%; 95% CI: 56%, 91%), and native T1 (14 of 26, 54%; 95% CI: 33%, 73%). Conclusion Collagen-targeted molecular MRI most accurately detected early onset of fibrosis, whereas the fibrogenesis probe Gd-Hyd proved most accurate for detecting treatment response. © RSNA, 2020 Online supplemental material is available for this article.

A252 FUNCTIONAL ANALYSIS OF GENETIC AETIOLOGIES IN A DOWNSTREAM OF TYROSINE KINASE (DOK) PROTEIN IN THE PATHOGENESIS OF PEDIATRIC INFLAMMATORY BOWEL DISEASE (IBD)

Background

IBD is a form of chronic inflammatory disorder of the gastrointestinal tract that arises due to genetic, environmental, immunological and microbial factors. The precise pathological mechanisms remain elusive. It is thought that the onset of pediatric IBD can largely be attributed to genetics. Muise lab, at SickKids, regularly screens children at the SickKids IBD clinic and through an international consortium to find possible genetic links to the disease. We report a patient at SickKids with biallelic mutations in DOK4 who has severe Crohn’s Disease along with other inflammatory conditions. Downstream of kinase (DOK) proteins are a family of adaptor molecules that serve as scaffolding proteins important in regulating cell signaling, especially in T cells. DOK4 has been shown to have negative regulatory effects on T cell activation but is also expressed across various other tissues where its function is yet to be determined. We predict that these mutations are causing immune cell dysregulation, which may be contributing to the patients IBD.

Aims

Through this study, we aim to enhance our understanding of the pathobiological mechanism of novel mutations in DOK4.

Methods

We have established T cell lines, expressing wild type and mutated DOK4, which will be used to perform functional tests, such as localization analysis through immunofluorescence and cytokine profiling, to check for T cell function. We have patient derived organoids, which will be used to assess changes in gut morphology using imaging techniques. We will also generate mutant zebrafish model that will be used to determine the susceptibility to colitis related to this mutation, disease progression and gut peristalsis using live imaging technology.

Results

Preliminary data shows variation in expression of the protein within patient derived peripheral blood mononuclear cells (PBMCs) compared to a healthy donor.

Conclusions

With this study, we hope to identify new therapeutic targets for patients with DOK4 mutations.

Funding Agencies

CIHRThe Leona M. and Harry B. Helmsley Charitable Trust

A33 THE ROLE OF A HOMOZYGOUS PROTEIN CODING VARIANT OF EPS8 IN THE PATHOGENESIS OF PEDIATRIC IBD

Background

The rate of onset for Inflammatory Bowel Disease (IBD) is rising worldwide—most significantly in the pediatric population. The pathogenesis of the disease involves a complicated interaction between the environment and genetics. Recent findings suggest that there is a broad range of rare, single-gene mutations that correlate with the IBD phenotype in children. Some of these single-gene defects can disrupt the epithelial barrier, which alters intestinal immune homeostasis. Epidermal Growth Factor Receptor Kinase Substrate 8 (EPS8) is crucial for the stabilization of F-actin by capping and bundling the barbed end. Previous literature shows that loss of expression of EPS8 disrupts the polymerization of F-actin in intestinal microvilli resulting in shortened brush borders. We identified a pediatric IBD patient with a homozygous missense EPS8 mutation(c.2099C>T, I700T) in the actin-binding domain. The patient presented with pancolitis, colonic strictures and other IBD-like symptoms at 6 weeks of age. Currently, the functional role of EPS8 in the pathogenesis of very early-onset IBD remains elusive.

Aims

1)To investigate if the patient with EPS8 mutation has microvilli disorganization.

2)To determine EPS8 localization in patient samples and cell models.

3)To clarify the mechanism of how the EPS8 mutation affects F-actin in vitro.

Ultimately, we want to clarify how the mutation of EPS8 might contribute to the onset of pediatric IBD.

Methods

A rare, damaging mutation in EPS8 was identified in a very early-onset IBD patient by Whole Exome Sequencing. From patient-derived colon biopsy samples, the localization of EPS8 and actin was visualized by immunofluorescence (IF) microscopy. The morphology of the patient’s intestinal microvilli was assessed using transmission electron microscopy (TEM). EPS8 expression was measured using western blot. An F-actin polymerization assay was performed comparing purified WT and mutant EPS8 protein to assess the rate of polymerization from monomeric G-actin to F-actin.

Results

IF microscopy of the colonic sections revealed lower co-localization of EPS8 and actin on the apical surfaces, compared to IBD and normal controls. Closer examination of the cell structure using TEM showed disruption of the microvilli in the EPS8 mutant, but not in IBD or normal controls. Western blots showed no differences in protein expression between wildtype and mutant EPS8 in HEK293T cells. F-actin polymerization assay revealed differences in the rate of G-actin to F-actin polymerization between wildtype and mutant EPS8.

Conclusions

The patient with EPS8 mutation had microvilli disorganization. EPS8 localized differently in the patient colon tissues compared to normal and IBD control samples. The EPS8 mutation may affect F-actin polymerization, which may lead to disruption of the microvilli.

Funding Agencies

CIHR

A39 NOVEL GAIN OF FUNCTION NON-RECEPTOR TYROSINE KINASE MUTATIONS ARE LINKED TO THE PATHOGENESIS OF VEOIBD

Background

Very early-onset inflammatory bowel disease (VEOIBD) is an emerging global disease, that results in inflammation of the digestive tract. Severe forms of VEOIBD can be caused by mutations in a single gene (monogenic variants) and, can result in death. A candidate gene which codes for a non-receptor tyrosine kinase (nRTK) has recently been implicated as a monogenic cause of IBD (unpublished). Whole exome sequencing was performed in two unrelated children who presented with symptoms of IBD identifying two distinct de novo gain of function mutations (S550Y and P342T). Both mutations are located in the highly conserved region of the nRTK, and were predicted to have similar downstream effects. Furthermore, four other patients with a variety of adult-onset immune disorders have recently been identified with rare variants in the same gene (M450I, R42P, A353T, V433M, S550F) but, their potential gain of function status remains to be determined. Studies show that this nRTK is an essential mediator in inflammation. It is expressed in both intestinal epithelial and immune cells however, its role in infantile IBD is unclear. This protein is first activated by phosphorylation and is linked to activating downstream transcription factors such as ERK and JNK. All these target proteins play a meaningful role in intestinal inflammation in patients with IBD.

Aims

Since we identified P342T and S550Y to be gain of function, we wanted to determine if the new variants exhibit a similar downstream impact on target protein expression levels when compared with S550Y and P342T. We also wanted to identify if all variants can be rescued with a known nRTK inhibitor. It is hypothesized that the new variants are gain of function and that all variants can be rescued with the inhibitor.

Methods

Using western blot analysis, the activation of ERK, JNK and nRTK was compared between wildtype (WT) and mutants. This in vitro method helped identify the degree of activation. For the second part of the study, HEK293T cells were treated with inhibitor to test for a rescue of phenotypes via western blot analysis.

Results

Results show an increased activation of nRTK, ERK and JNK in all variants with S550Y and S550F having the highest activation. Furthermore, pharmacological inhibition using small molecular kinase inhibitors resulted in decreased activation of nRTK, ERK and JNK suggesting a rescue of phenotypes.

Conclusions

Characterizing the downstream functional impact of these nRTK variants is an important first step to determine if gain of function nRTK mutations drive IBD. With a rising prevalence of IBD worldwide, these findings may lead to the development of pharmacological nRTK inhibitors as a novel personalized therapeutic approach for these patients and possibly for the broader IBD population.

Funding Agencies

CIHR

Magnetic trapping of SH radicals

Magnetic trapping of SH radicals, produced via the photostop technique, has been demonstrated. H₂S in a skimmed, supersonic molecular beam was photodissociated at 212.8 nm to produce SH inside a 330 mK deep static magnetic trap. The molecular-beam speed was controlled by the mixing ratio of H₂S in Kr to match the recoil velocity of the SH photofragments such that some SH radicals were produced with near-zero laboratory-frame velocity. The density of SH radicals in the ²Π_3/2, v = 0, J = 3/2 state was followed by (2 + 1) REMPI over seven orders of magnitude of signal intensity. 5 ms after photodissociation, SH radicals moving faster than the capture velocity of 13 m s^-1 had left the trap. The 1/e trap lifetime of the remaining SH radicals was 40 ± 10 ms at an estimated density of 5 × 10⁴ molecules per cm³. Photostop offers a simple and direct way to accumulate absolute ground state molecules in a variety of traps.

Open-label study of faldaprevir plus peginterferon and ribavirin in hepatitis C virus genotype 1-infected patients who failed placebo plus peginterferon and ribavirin

Faldaprevir, a hepatitis C virus (HCV) NS3/4A protease inhibitor, was evaluated in HCV genotype 1-infected patients who failed peginterferon and ribavirin (PegIFN/RBV) treatment during one of three prior faldaprevir trials. Patients who received placebo plus PegIFN/RBV and had virological failure during a prior trial were enrolled and treated in two cohorts: prior relapsers (n = 43) and prior nonresponders (null responders, partial responders and patients with breakthrough; n = 75). Both cohorts received faldaprevir 240 mg once daily plus PegIFN/RBV for 24 weeks. Prior relapsers with early treatment success (ETS; HCV RNA <25 IU/mL detectable or undetectable at week 4 and <25 IU/mL undetectable at week 8) stopped treatment at week 24. Others received PegIFN/RBV through week 48. The primary efficacy endpoint was sustained virological response (HCV RNA <25 IU/mL undetectable) 12 weeks post treatment (SVR12). More prior nonresponders than prior relapsers had baseline HCV RNA ≥ 800,000 IU/mL (80% vs 58%) and a non-CC IL28B genotype (91% vs 70%). Rates of SVR12 (95% CI) were 95.3% (89.1, 100.0) among prior relapsers and 54.7% (43.4, 65.9) among prior nonresponders; corresponding ETS rates were 97.7% and 65.3%. Adverse events led to faldaprevir discontinuations in 3% of patients. The most common Division of AIDS Grade ≥ 2 adverse events were anaemia (13%), nausea (10%) and hyperbilirubinaemia (9%). In conclusion, faldaprevir plus PegIFN/RBV achieved clinically meaningful SVR12 rates in patients who failed PegIFN/RBV in a prior trial, with response rates higher among prior relapsers than among prior nonresponders. The adverse event profile was consistent with the known safety profile of faldaprevir.

Seasonal variation in accumulation of persistent organic pollutants in an Arctic marine benthic food web

The aim of the present study was to investigate seasonal variation in persistent organic pollutant (POP) concentrations, as well as food-web biomagnification, in an Arctic, benthic marine community. Macrozoobenthos, demersal fish and common eiders were collected both inside and outside of Kongsfjorden, Svalbard, during May, July and October 2007. The samples were analysed for a selection of legacy chlorinated POPs. Overall, low levels of POPs were measured in all samples. Although POP levels and accumulation patterns showed some seasonal variation, the magnitude and direction of change was not consistent among species. Overall, seasonality in bioaccumulation in benthic biota was less pronounced than in the pelagic system in Kongsfjorden. In addition, the results indicate that δ(15)N is not a good predictor for POP-levels in benthic food chains. Other factors, such as feeding strategy (omnivory, necrophagy versus herbivory), degree of contact with the sediment, and a high dependence on particulate organic matter (POM), with low POP-levels and high δ(15)N-values (due to bacterial isotope enrichment), seem to govern the uptake of the different POPs and result in loads deviating from what would be expected consulting the trophic position alone.

The hepatitis B e antigen suppresses IL-1β-mediated NF-κB activation in hepatocytes

Previous clinical studies have demonstrated an association between the hepatitis B e antigen and Toll-like receptor (TLR) expression and signalling. Therefore, the aim of this study was to develop an in vitro assay to measure the effect of hepatitis B virus proteins, including the precore protein, on signalling mediated by members of the Toll-like/interleukin 1 (TIR) superfamily, by measuring NF-κB promoter activity. The basal level of NF-κB reporter activity was measured in three hepatocyte cell lines (Huh7, HepG2 and PH5CH8) and one kidney cell line (HEK293) using a luciferase assay. All cell lines were virtually refractory to stimulation with lipopolysaccharide; however, PH5CH8 cells had a robust activation of NF-κB in response to IL-1β stimulation, with ∼ 40-fold higher activation than the unstimulated control, a higher degree of activation than that observed in either Huh7 and HepG2, or HEK293 and HEK293-TLR2 cells. In PH5CH8 cells transfected with pCI expression constructs and stimulated with IL-1β, we showed that the precursor form of the precore protein, p25, inhibits NF-κB activation by up to 30% and the cytosolic form, p22, inhibits NF-κB activation by 70%. The core protein, p21, which shares significant homology with the precore protein except for a 10-amino acid extension at the N-terminus, had no effect on NF-κB activation. We hypothesize that the inhibition of IL-1β-mediated NF-κB activation by the precore protein may be a mechanism that allows the virus to persist, suggesting a role for the pool of precore protein that remains intracellular.

Transcriptional regulation of plant senescence: from functional genomics to systems biology

Leaf senescence is an active process that involves the increased expression of many hundreds of genes. Many putative transcription factors show enhanced transcription during leaf senescence in Arabidopsis and functional analysis of these should help to indicate their role in controlling gene expression during leaf senescence. In this paper, we describe the analysis of knockout insertion mutants in two different senescence-enhanced genes, one encodes a heat shock transcription factor and the other a zinc finger protein. Plants mutated in these genes show accelerated leaf senescence and reduced tolerance to drought stress, indicating that expression of these genes during senescence has a protective role to maintain viability during this essential developmental process. Analysis of gene expression changes in both mutants compared to the wild-type plants indicates an increased rate of senescence but does not show clearly the pathway that is dependent on these genes for expression. The complexities of signalling networks in plant stress and the plasticity of plant responses mean that the direct consequences of mutation are very difficult to define. The usefulness of this type of approach to address the burning question of how senescence is regulated is discussed, and an alternative approach aimed at a more global analysis of gene regulation using systems biology methods is described.

Oxford experience with neoadjuvant chemotherapy and surgical resection for esophageal adenocarcinomas and squamous cell tumors

The Medical Research Council trial for oesophageal cancer (OEO2) trial demonstrated a clear survival benefit from neoadjuvant chemotherapy in resectable esophageal carcinoma. Since February 2000 it has been our practice to offer this chemotherapy regime to patients with T2 and T3 or T1N1 tumors. We analyzed prospectively collected data of patients who received neoadjuvant chemotherapy prior to esophageal resection under the care of a single surgeon. Complications of treatment and overall outcomes were evaluated. A total of 194 patients had cisplatin and 5-fluorouracil prior to esophageal resection. Six patients (5.7%) had progressive disease and were inoperable (discovered in four at surgery). During chemotherapy one patient died and one perforated (operated immediately). Complications including severe neutropenia, coronary artery spasm, renal impairment and pulmonary edema led to the premature cessation of chemotherapy in 12 patients (6.2%). A total of 182 patients with a median age of 63 (range 30-80), 41 squamous and 141 adenocarcinomas underwent surgery. Operations were 91 left thoracoabdominal (50%), 45 radical transhiatal (25%), 40 Ivor-Lewis (22%) and six stage three (3%), and 78.6% had microscopically complete (R0) resections. Median survival was 28 months with 77.3% surviving for 1 year and 57.7% for 2 year. In hospital mortality was 5.5% and anastomotic leak rate 7.7%. A radical surgical approach to the primary tumor in combination with OEO2 neoadjuvant chemotherapy has led to a high R0 resection rate and good survival with acceptable morbidity and mortality.

Oncogenic re-wiring of cellular signaling pathways

Signaling pathways in mammalian cells are assembled and regulated by a finely controlled network of protein-protein and protein-phospholipid interactions, mediated by dedicated signaling domains and their cognate binding motifs. The domain-based modular architecture of signaling proteins may have facilitated the evolution of complex biological systems, and can be exploited experimentally to generate synthetic signaling pathways and artificial mechanisms of autoregulation. Pathogenic proteins, such as those encoded by bacteria and viruses, frequently form ectopic signaling complexes to respecify cellular behavior. In a similar fashion, proteins expressed as a consequence of oncogenic fusions, mutations or amplifications can elicit ectopic protein-protein interactions that re-wire signaling pathways, in a fashion that promotes malignancy. Compounds that directly or indirectly reverse these aberrant interactions offer new possibilities for therapy in cancer.

Benchmarking the current dispensing rate of Welsh hospital pharmacies

BACKGROUND

There is a need to develop capacity measures for pharmacy services for strategic purposes, to provide guidance on safe working limits and to contribute to the target 40% reduction in serious medication errors by 2005. Attempts have been made to quantify workloads in the form of items/person/hour (i/p/h). However, much of these data are anecdotal, small scale or associated with vague methodology.

OBJECTIVE

We estimate national average dispensing rates by collecting accurate data from secondary care dispensaries across Wales.

METHOD

Seventeen sites collected hourly data relating to staff time and items dispensed over a 3-day period. The result showed a Welsh national average for non-specialist hospital pharmacy dispensing rates of 9.9 items/person/h (95% CI = 0.9, n = 17). There was a significant positive association between hospital size and telephone interruptions (r(s) = 0.83, P < 0.001) but no correlation between hospital size and dispensing rates (r(s) = 0.06, P = 0.822).

Clinical emergence of entecavir-resistant hepatitis B virus requires additional substitutions in virus already resistant to Lamivudine

Entecavir (ETV) exhibits potent antiviral activity in patients chronically infected with wild-type or lamivudine (3TC)-resistant (3TC(r)) hepatitis B virus (HBV). Among the patients treated in phase II ETV clinical trials, two patients for whom previous therapies had failed exhibited virologic breakthrough while on ETV. Isolates from these patients (arbitrarily designated patients A and B) were analyzed genotypically for emergent substitutions in HBV reverse transcriptase (RT) and phenotypically for reduced susceptibility in cultures and in HBV polymerase assays. After 54 weeks of 3TC therapy, patient A (AI463901-A) received 0.5 mg of ETV for 52 weeks followed by a combination of ETV and 100 mg of 3TC for 89 weeks. Viral rebound occurred at 133 weeks after ETV was started. The 3TC(r) RT substitutions rtV173L, rtL180M, and rtM204V were present at study entry, and the additional substitutions rtI169T and rtM250V emerged during ETV-3TC combination treatment. Reduced ETV susceptibility in vitro required the rtM250V substitution in addition to the 3TC(r) substitutions. For liver transplant patient B (AI463015-B), previous famciclovir, ganciclovir, foscarnet, and 3TC therapies had failed, and RT changes rtS78S/T, rtV173L, rtL180M, rtT184S, and rtM204V were present at study entry. Viral rebound occurred after 76 weeks of therapy with ETV at 1.0 mg, with the emergence of rtT184G, rtI169T, and rtS202I substitutions within the preexisting 3TC(r) background. Reduced susceptibility in vitro was highest when both the rtT184G and the rtS202I changes were combined with the 3TC(r) substitutions. In summary, infrequent ETV resistance can emerge during prolonged therapy, with selection of additional RT substitutions within a 3TC(r) HBV background, leading to reduced ETV susceptibility and treatment failure.

Phase II study to evaluate combining gemcitabine with flutamide in advanced pancreatic cancer patients

A phase II study was undertaken to determine the safety of combining flutamide with gemcitabine, with response rate being the primary end point. Twenty-seven patients with histologically proven, previously untreated, unresectable pancreatic adenocarcinoma received gemcitabine, 1 g m(-2) intravenously on days 1, 8 and 15 of a 28 day cycle, and flutamide 250 mg given orally three times daily. Treatment was halted if there was unacceptable toxicity, or evidence of disease progression. Toxicity was documented every cycle. Tumour assessment was undertaken after cycles 2 and 4, and thereafter at least every additional four cycles. One hundred and seventeen cycles of treatment were administered, median four cycles per patient (range 1-18). Gemcitabine combined with flutamide was well tolerated, with most toxicities being recorded as grade 1 or 2 and only nine treatment cycles associated with grade 3 toxicity. The most frequent toxicity was myelosuppression. One case of transient jaundice was recorded. The commonest symptomatic toxicity was nausea and vomiting. The response rate was 15% (four partial responses), median survival 6 months and 22% of patients were alive at 1 year. These results suggest antitumour activity of the combination therapy to be equivalent to single agent gemcitabine.

The role of the mora in the timing of spontaneous Japanese speech

This study investigates whether the mora is used in controlling timing in Japanese speech, or is instead a structural unit in the language not involved in timing. Unlike most previous studies of mora-timing in Japanese, this article investigates timing in spontaneous speech. Predictability of word duration from number of moras is found to be much weaker than in careful speech. Furthermore, the number of moras predicts word duration only slightly better than number of segments. Syllable structure also has a significant effect on word duration. Finally, comparison of the predictability of whole words and arbitrarily truncated words shows better predictability for truncated words, which would not be possible if the truncated portion were compensating for remaining moras. The results support an accumulative model of variance with a final lengthening effect, and do not indicate the presence of any compensation related to mora-timing. It is suggested that the rhythm of Japanese derives from several factors about the structure of the language, not from durational compensation.

Grb2 and Shc adapter proteins play distinct roles in Neu (ErbB-2)-induced mammary tumorigenesis: implications for human breast cancer

Amplification of the Neu (ErbB-2 or HER-2) receptor tyrosine kinase occurs in 20 to 30% of human mammary carcinomas, correlating with a poor clinical prognosis. We have previously demonstrated that four (Y1144 Y1201, Y1227 and Y1253) of the five known Neu autophosphorylation sites can independently mediate transforming signals. The transforming potential of two of these mutants correlates with their capacity to recruit Grb2 directly to Y1144 (YB) or indirectly through Shc to Y1227 (YD). Here, we demonstrate that these transformation-competent neu mutants activate extracellular signal-regulated kinases and stimulate Ets-2-dependent transcription. Although the transforming potential of three of these mutants (YB, YD, and YE) was susceptible to inhibition by Rap1A, a genetic antagonist of Ras, the transforming potential of YC was resistant to inhibition by Rap1A. To further address the significance of these ErbB-2-coupled signaling molecules in induction of mammary cancers, transgenic mice expressing mutant Neu receptors lacking the known autophosphorylation sites (NYPD) or those coupled directly to either Grb2 (YB) or Shc (YD) adapter molecules were derived. In contrast to the NYPD strains, which developed focal mammary tumors after a long latency period with low penetrance, all female mice derived from YB and YD strains rapidly developed mammary tumors. Although female mice from several independent YB or YD lines developed mammary tumors, the YB strains developed lung metastases at substantially higher rates than the YD strains. These observations argue that Grb2 and Shc play important and distinct roles in ErbB-2/Neu-induced mammary tumorigenesis and metastasis.

Japanese mora-timing: a review

Japanese is often called a 'mora-timed' language, and contrasted with 'stress- timed' or 'syllable-timed' languages. The definition of what constitutes mora-timing has undergone several revisions, and a wide variety of experimental evidence both for and against mora-timing has been presented. This article reviews the hypotheses, the means of testing them, and the results of nearly 40 years of experimental work on mora-timing in Japanese, and suggests directions for future work in this area.

Purification and cloning of TF2: A novel protein that binds a regulatory site of the gp2 promoter in Dictyostelium

The glycogen phosphorylase-2 gene is developmentally regulated and plays a central role in cellular differentiation in Dictyostelium. There are two isozymes of glycogen phosphorylase, GP1 and GP2. Both forms are developmentally regulated; gp1 is expressed in undifferentiated cells and gp2 during differentiation. We report here the identification, purification, and cloning of a second gp2 DNA-binding factor called TF2. This protein demonstrates a high specificity for a transcriptional regulatory element, the 5' C box. TF2 was first detected with electrophoretic mobility shift assays of DEAE chromatographic fractions of cell-free extracts. The specificity of TF2 for the 5' C box was tested by competition analysis using six other oligonucleotides. Purification of TF2 was achieved by ion-exchange chromatography, DNA affinity chromatography, gel filtration chromatography, and preparative SDS-PAGE. SDS-PAGE analysis indicated an apparent subunit molecular weight of 28 kDa. The apparent molecular weight of the native protein as estimated by gel filtration was about 53 kDa. This suggested that TF2 binds gp2 as a homodimer. Southern blot analysis indicated that there is only one form of the tf2 gene. Northern analysis showed little or no expression of tf2 in undifferentiated cells. During development tf2 expression increases up to a maximum at 8 h and then decreases in later stages. Attempts to disrupt the gene suggest that tf2 mutation may be lethal.

Population distribution and effects on drug metabolism of a genetic variant in the 5' promoter region of CYP3A4

BACKGROUND

There are large interindividual differences in CYP3A4 expression and in the metabolism of drug substrates for this enzyme. We and others have identified a polymorphism in the 5' promotor region of the CYP3A4 gene; however, its functional significance is not currently known. This study was conducted to determine whether this polymorphism plays a clinically important role in determining CYP3A4 phenotype.

METHODS

An adenine (A) to guanine (G) transition was identified in the 5' promotor region of the CYP3A4 gene at position -292 (from the start codon), in a sequence motif known as the nifedipine-specific element. The frequency of this polymorphism was assessed in 802 healthy volunteers from five broadly defined racial groups. The population distribution of the G allele in these groups was as follows: white Americans (3.6%; n = 273), black Americans (54.6%, n = 186), Hispanic Americans (9.3%; n = 188), Japanese Americans (0.0%; n = 77), and Chinese Americans (0.0%; n = 78). In a subsequent study, 90 additional black Americans were genotyped, and a subset of the homozygous subjects (AA, n = 8; GG, n = 23) were given the CYP3A4 probe substrates erythromycin and nifedipine to allow genotype-phenotype comparisons to be made.

RESULTS

There was no difference in the rate of CYP3A4-dependent demethylation of erythromycin (erythromycin breath test) or the pharmacokinetics of nifedipine or its CYP3A4-dependent metabolite dehydronifedipine between the two genotype groups (AA or GG).

CONCLUSIONS

This promotor region polymorphism does not appear to play a major role in determining constitutive CYP3A4 expression.

Anxiety and the dexamethasone suppression test monitored with saliva

To assess the effect of anxiety on response to the Dexamethasone Suppression Test (DST), cortisol concentrations were determined in patients who had various diagnoses, with anxiety as a secondary characteristic. Saliva was collected before and after venepuncture at 4:05 PM following completion of the Leeds Questionnaire at 3:00 PM. Matrix effects, which caused an initial artefactual decrease in cortisol levels in some saliva samples in patients with high anxiety, could be eliminated by repeated freezing/thawing. There was no significant difference between salivary cortisol concentrations before and after venepuncture, indicating that variability in response to the DST is not a correlate of anxiety and stressful venepuncture. There was no association between anxiety scores and plasma or salivary cortisol values: thus, anxiety is unlikely to be a major contributory cause of nonsuppression of hypercortisolemia in the DST.

Peripheral serotoninergic receptor sensitivity in senile dementia of the Alzheimer type

Platelet aggregation induced by 5-hydroxytryptamine (5-HT) was used as a measure of the functional responsiveness of peripheral 5-HT receptors in controls and drug-free patients suffering from senile dementia of Alzheimer type (SDAT). No significantly different aggregatory response (5-HT/ADP ratio) was noted between the two groups of subjects. If the receptor mediating this response is a 5-HT2 receptor, there is no evidence to suggest that the functional activity of this system is abnormal in SDAT.

In vivo administration of anti-CD4 monoclonal antibody prolongs survival in longtailed macaques with experimental allergic encephalomyelitis

The in vivo administration of monoclonal antibody (mAb) to the CD4 antigen associated with helper T cells has been successful in prolonging the survival of nonhuman primates with experimental allergic encephalomyelitis (EAE). EAE was induced in 17 outbred longtailed macaques (Macaca fascicularis) by inoculation of homologous myelin basic protein (BP) in complete Freund's adjuvant (CFA). Treatment was begun at the onset of clinical signs. Eleven animals were treated with anti-CD4 mAb Leu3a (eight) or OKT4a (three). Of the six control animals, two received anti-CD8 mAb (Leu2a), and four were treated with saline. Specific T- and B-cell subsets which have been implicated in the development of EAE were monitored throughout the course of the disease by one- and two-color immunofluorescence (IF). The monkey anti-BP antibody and anti-mouse immunoglobulin (IgG) responses were measured by enzyme-linked immunoassay (ELISA) techniques, as were the levels of free-circulating murine IgG. The nature of the infiltrating lymphocytes in the brain was evaluated histologically post mortem. Our results indicate that anti-CD4 mAb can prolong survival and in some cases completely reverse the clinical appearance of the disease; however, relapses did occur. Treatments with Leu3a or OKT4a anti-CD4 mAbs reversed the ongoing depletion of CD4+ and CD8+ cells caused by the development of EAE and appeared to reduce the size and degree of inflammation in brain lesions. These treatments did not induce immunologic tolerance to mouse IgG since all of the anti-CD4-treated animals produced high titers of anti-mouse IgG antibodies. Treatment with Leu2a (anti-CD8) had no effect on the development of EAE. These results suggest that CD4+ cells are important to the pathogenesis of EAE in macaques and that manipulation of this subset with monoclonal antibodies may provide effective treatment of human demyelinating disease.

Restoration of impaired B- and T-lymphocyte subsets and functions in vitro by isoprinosine in prodromal homosexuals and AIDS patients

Functional and phenotypical parameters demonstrated significant aberrations in both prodromal males and patients with the acquired immune deficiency syndrome (AIDS). Impaired B-cell functions as quantitated by Staphylococcus aureas Cowan Strain I (SAC) and pokeweed mitogen (PWM)-induced blastogenesis, intracytoplasmic immunoglobulins and spontaneous immunoglobulin were associated with a significant decrease in Leu3+ cells but unrelated to Leu2+ lymphocytes. The functional subsets of the latter were further defined by monoclonal antibodies (Leu8 and HLA-DR) applying dual color flow cytometry. Activated and effector-suppressor subsets with the phenotypes Leu2+ HLA-DR+ and Leu2+ Leu8- were elevated while both subsets of helper and suppressor-inducing helper lymphocytes, Leu3+ Leu8- and Leu3+ Leu8+, were depressed. These data demonstrated a broad spectrum of dysfunction involving all 3 stages of B-cell development in AIDS as well as possible defects in the feedback suppressor loop which regulates both the helper and suppressor T-lymphocyte system and B-cell functions. While in vitro incubation with isoprinosine had no modulative effect on SAC-induced blastogenesis (resting B-cell activities), it did modulate both PHA, PWM-induced transformation and the spontaneous secretion of immunoglobulins (partially and fully activated B-cell activities). In co-incubation with PWM, isoprinosine augmented the expression of inducer cells for helper functions while enhancing to normal level the number of suppressor-inducing helper cells. In addition, it reduced activated and effector-suppressor cells to near normal range in the PBL of high risk homosexuals. Only marginal modulation, however, was observed in suppressor subsets of AIDS subjects. This interference with the defective feedback loop may account for the selective clinical and immunoregulatory actions of this drug.

High frequency of immune dysfunctions in asbestos workers and in patients with malignant mesothelioma

We have examined the primary immune responses, the numbers of total T (T11+) cells, T-helper (T4+) cells, T-suppressor (T8+) cells, and natural killer (NK) (Leu7+) cells, in 118 healthy control subjects and compared the data to those obtained from 20 patients with clinically diagnosed malignant mesothelioma and 375 long-term asbestos workers without neoplasia. The absolute numbers of total T (T11+) and T-helper (T4+) cells were normal in asbestos workers without neoplasia but were significantly reduced in patients with mesothelioma. T-suppressor (T8+) cells, on the other hand, remained unchanged in the patients but were significantly elevated among the asbestos workers. This resulted in a marked reduction in T-helper (Th) to T-suppressor (Ts) ratios in mesothelioma patients and in asbestos workers. Seventy percent of the mesothelioma patients (14 of 20) had significantly depressed NK-cell activity which could be augmented but not normalized by coincubation in patients' peripheral blood lymphocytes (PBL) with interferon (IFN). Among the asbestos workers three distinctive subgroups could be identified: heightened (H-NK), normal (N-NK), and low (L-NK) NK activity. The NK activity of the L-NK group could be stimulated but not normalized by coincubation with IFN, a finding closely resembling that in malignant mesothelioma patients. Phenotyping of the circulating NK cells revealed a unique Leu7+ subset in increased numbers with a brightly fluorescent property in stable mesothelioma patients with relatively stable or slowly progressive disease and in more than 30% of the asbestos workers.(ABSTRACT TRUNCATED AT 250 WORDS)