Hong Kong consensus recommendations on the management of pancreatic ductal adenocarcinoma

This project was undertaken to develop the first set of consensus statements regarding the management of pancreatic ductal adenocarcinoma (PDAC) in Hong Kong, with the goal of providing guidance to local clinicians. A multidisciplinary panel of experts discussed issues surrounding current PDAC management and reviewed evidence gathered in the local context to propose treatment recommendations. The experts used the Delphi approach to finalise management recommendations. Consensus was defined as ≥80% acceptance among all expert panel members. Thirty-nine consensus statements were established. These statements cover all aspects of PDAC management, including diagnosis, resectability criteria, treatment modalities according to resectability, personalised management based on molecular profiling, palliative care, and supportive care. This project fulfils the need for guidance regarding PDAC management in Hong Kong. To assist clinicians with treatment decisions based on varying levels of evidence and clinical experience, treatment options are listed in several consensus statements.

Best practices in epidermal growth factor receptor T790M testing for advanced non-small-cell lung cancer in Hong Kong

The T790M mutation in the epidermal growth factor receptor gene causes most acquired resistance to firstor second-line epidermal growth factor receptor-tyrosine kinase inhibitors in advanced non-small-cell lung cancer. The results of T790M testing can guide subsequent treatment. Despite the availability of guidelines from international organisations, T790M testing practices in Hong Kong must be streamlined and adapted to the Hospital Authority setting. To address this issue, a panel of experts in oncology and pathology met for discussion of key topics regarding T790M testing practices in Hong Kong, including the appropriate timing of testing and re-testing, as well as optimal testing methods. All panel members voted on the results of the discussion to achieve consensus. Items supported by a majority vote were adopted as consensus statements regarding current best practices for T790M testing in Hong Kong. Among the topics discussed, the panel agreed that T790M testing should be initiated upon radiological progression, including symptomatic disease progression or central nervous system-only progression. The experts also preferred initial testing with liquid biopsy, using the widely available digital polymerase chain reaction platform. This document provides the final consensus statements, as well as a testing and treatment workflow, for clinicians in Hong Kong to use as guidance in T790M testing.

Outcomes of cardiac CT investigations in patients from the Rapid Access Chest Pain clinic with consideration to additional CT modalities and individual risk factors

Funding Acknowledgements

Type of funding sources: None.

Coronary CT is a first line investigation according to NICE guidelines, yet there are still uncertainties in its ability to decrease adverse event rates. The high sensitivity and high negative predictive value of coronary CT only validates low to moderate pre-test probability of attaining significant CAD due to its low positive predictive value. Improving outcomes in coronary CT could avoid events and limit the use of invasive modalities such as invasive coronary angiography. Increased probability of MACE with presence of risk factors could also raise the merit of risk stratification utilization for better classification.

This study provides insight into the effectiveness of CT as a first-line investigation for new onset angina referred to RACPC regardless of CAD probability and any further testing. Data differences on outcome probabilities in risk stratification utilization and different CT modalities, both coronary calcium scoring and coronary angiography, raised notion that the incremental value of these tools should not be overlooked. End-outcomes would compromise of MACE composites after a 6-month follow-up. We hypothesize that patients investigated with coronary CT as opposed to without, with presence or absence of functional testing, would grant better clinical outcomes.

Data on 155 patients who registered in RACPC were identified and collected from Brunei Health Information Management Systems for a one-year period (August 2018- August 2019). Information on sociodemographic, risk factors, further diagnostic testing, CT reports and event follow-up at 6 months were extracted, subject to availability. Probability of CAD in patients were classified according to CCS and CTCA results.

CAD was detected in 62 (40.0%) patients with non-obstructive or obstructive CAD in addition to low to high calcium scores. Over the 6-month follow-up period, MACE occurred in 8 patients in the CT group (6.3%) and 4 (13.8%) without CT. 126 (81.3%) patients with CT did not attain MACE (p = 0.19) and chances of getting CABG after adjustments with co- founding factors were significantly lower than without CT [HR = 2.654e-06; 95% CI = 2.204e-07-3.195e-05; p= <0.001]. A higher event probability was associated with a high CCS (41.1%) (p= <0.001) than abnormal CTCA (11.4%) (p = 0.018). MACE was also associated with multiple risk factors such as age (p= <0.001), hypertension (p = 0.001), diabetes (p= <0.001), high cholesterol(p = 0.027), and abnormal total cholesterol (0.010) and creatinine levels [serum creatinine, p= 0.017; creatinine clearance, p = 0.006].

Outcomes measured were not significantly better in those with cardiac CT however risk of coronary artery bypass graft was significantly lower. CCS is better than CTCA in event prospects but both possess promising prognostic values in healthy arteries. Multiple CAD risk factors associated with MACE were likely as a result of intense atherosclerosis, marking appeal for risk stratifications and preventive measures. Abstract Figure. Kaplan-Meier curves for MACE  Abstract Figure. Multiple cox regression models

Combination atezolizumab, bevacizumab, pemetrexed and carboplatin for metastatic EGFR mutated NSCLC after TKI failure

INTRODUCTION

Acquired resistance to TKI is an important unmet need in the management of EGFR mutated lung cancer. Recent clinical trial IMPower150 suggested that combination approach with VEGF inhibitor, check point inhibitor immunotherapy and platinum-based chemotherapy was effective in oncogene driven lung cancer. The current trial examined the efficacy of a modified regimen in an EGFR mutated cohort.

METHODS

An open-labelled, single arm, phase II study was conducted in patients with EGFR mutated NSCLC who had progressed on at least one EGFR TKI. For those with T790M mutation, radiological progression on osimertinib was required for enrolment. Patients were treated with combination atezolizumab (1200 mg), bevacizumab (7.5 mg/kg), pemetrexed (500 mg/m2) and carboplatin (AUC 5) given once every 3 weeks until progression.

RESULTS

Forty patients were enrolled. Median age was 62 (range 45-76) years. More than one half (23/40, 57.5%) had progressed on osimertinib. PD-L1 expression was < 1% in 52.5%. Median follow-up time was 17.8 months. ORR was 62.5%. Median PFS was 9.4 months (95% CI: 7.6 - 12.1). One year OS was 72.5% (95% CI: 0.56-0.83). Treatment related grade 3 or above adverse events (AE) occurred in 37.5% (15/40). Immune-related AE occurred in 32.5% (13/40) patients. Quality of life measures of function and symptoms did not change significantly throughout the course of treatments. Post-trial rechallenge with EGFR TKI containing regimen resulted in PFS of 5.8 months (95% CI 3.9-10.0 months).

CONCLUSION

Combination approach of atezolizumab, bevacizumab, pemetrexed and carboplatin achieved promising efficacy in metastatic EGFR mutated NSCLC after TKI failure. The results were comparable with taxane based regimen of IMPower150 while toxicity profile was improved.

POS0417 EXOGENOUS CXCL5 RESTORES ENDOGENOUS BLOOD-TISSUE CHEMOKINE GRADIENT TO IMPROVE SURVIVAL IN MURINE LUPUS

Background:

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease that is potentially fatal. There is an unmet need to improve current therapies. In patients with SLE, we observed that serum CXCL5 levels were significantly lower than healthy control subjects and negatively correlated with disease activity(1-9).

Objectives:

The aim of this study is to elucidate the effect of supplemental serum CXCL5 in abrogating the pathological processes of SLE.

Methods:

Ten doses of exogenous CXCL5 (3µg/kg) was administered to 16-week-old Faslpr mice weekly by intravenous injection. Mice were monitored for 10 weeks. Splenic immune profile was measured by flow cytometry. Circulating cytokine and immunoglobulin profile were detected by Luminex technology. Renal function was evaluated by urinary spot albumin creatinine ratio. In situ renal immune cell infiltration and complement 3 deposition were detected by Haematoxylin and Eosin (H&E) and immunohistochemistry staining. The molecular pathways involved were examined by RNA sequencing.

Results:

In Faslpr mice, intravenous administration of exogenous CXCL5 significantly improved mouse survival with concomitant reduction of autoantibody secretion, proteinuria, complement 3 deposition, neutrophil infiltration and lupus nephritis classes. Through evaluating the changes of immune profile, cytokine profile and molecular pathways, we found that intravenous CXCL5 reduced inflammation via an orchestral effect of regulating neutrophil trafficking and modulating helper T cell-mediated immune response. Pharmacokinetic and real-time Polymerase Chain Reaction studies further demonstrated that this orchestration was triggered by a cascade reaction - restoring vascular under-expressed CXCL5 by an exogenous stimulation, re-establishing the normal serum levels of endogenous CXCL5 and reverting the CXCL5 chemokine gradient between inflamed tissues and blood circulation.

Conclusion:

Managing the dysregulation of CXCL5 by exogenous supplement may provide a new option for SLE therapy.

References:

[1]Dufies M, Grytsai O, Ronco C, et al. New CXCR1/CXCR2 inhibitors represent an effective treatment for kidney or head and neck cancers sensitive or refractory to reference treatments. Theranostics. 2019;9(18):5332-5346. doi:10.7150/thno.34681

[2]Yildirim K, Colak E, Aktimur R, et al. Clinical Value of CXCL5 for Determining of Colorectal Cancer. Asian Pac J Cancer Prev. Sep 26 2018;19(9):2481-2484. doi:10.22034/apjcp.2018.19.9.2481

[3]Wu K, Yu S, Liu Q, Bai X, Zheng X. The clinical significance of CXCL5 in non-small cell lung cancer. Onco Targets Ther. 2017;10:5561-5573. doi:10.2147/ott.s148772

[4]Zhao J, Ou B, Han D, et al. Tumor-derived CXCL5 promotes human colorectal cancer metastasis through activation of the ERK/Elk-1/Snail and AKT/GSK3beta/beta-catenin pathways. Mol Cancer. Mar 29 2017;16(1):70. doi:10.1186/s12943-017-0629-4

[5]Han KQ, Han H, He XQ, et al. Chemokine CXCL1 may serve as a potential molecular target for hepatocellular carcinoma. Cancer Med. Oct 2016;5(10):2861-2871. doi:10.1002/cam4.843

[6]Pappa CA, Tsirakis G, Kanellou P, et al. Monitoring serum levels ELR+ CXC chemokines and the relationship between microvessel density and angiogenic growth factors in multiple myeloma. Cytokine. Dec 2011;56(3):616-20. doi:10.1016/j.cyto.2011.08.034

[7]Zhang L, Li H, Ge C, et al. CXCL3 contributes to CD133(+) CSCs maintenance and forms a positive feedback regulation loop with CD133 in HCC via Erk1/2 phosphorylation. Sci Rep. Jun 3 2016;6:27426. doi:10.1038/srep27426

[8]Matsubara J, Honda K, Ono M, et al. Reduced plasma level of CXC chemokine ligand 7 in patients with pancreatic cancer. Cancer Epidemiol Biomarkers Prev. Jan 2011;20(1):160-71. doi:10.1158/1055- 9965.epi-10-0397

[9]Ma Y, Ren Y, Dai ZJ, Wu CJ, Ji YH, Xu J. IL-6, IL-8 and TNF-alpha levels correlate with disease stage in breast cancer patients. Adv Clin Exp Med. May-Jun 2017;26(3):421-426. doi:10.17219/acem/62120

Disclosure of Interests:

None declared

Modeling Stripe Formation on Growing Zebrafish Tailfins

As zebrafish develop, black and gold stripes form across their skin due to the interactions of brightly colored pigment cells. These characteristic patterns emerge on the growing fish body, as well as on the anal and caudal fins. While wild-type stripes form parallel to a horizontal marker on the body, patterns on the tailfin gradually extend distally outward. Interestingly, several mutations lead to altered body patterns without affecting fin stripes. Through an exploratory modeling approach, our goal is to help better understand these differences between body and fin patterns. By adapting a prior agent-based model of cell interactions on the fish body, we present an in silico study of stripe development on tailfins. Our main result is a demonstration that two cell types can produce stripes on the caudal fin. We highlight several ways that bone rays, growth, and the body-fin interface may be involved in patterning, and we raise questions for future work related to pattern robustness.

Partial complementation between the immediate early proteins ICP4 of herpes simplex virus type 1 and IE180 of pseudorabies virus

We previously described that the immediate early (IE) IE180 protein of PRV can down-regulate the transactivation of the ICP4 promoter of HSV-1, and that the d120 virus (an ICP4-deficient HSV-1 strain) can partially replicate its viral DNA in the presence of the IE180 protein. Herein, we demonstrate that this partial complementation of d120 by IE180 is sufficient for transcription of β, γ1 and γ2 products such as DNA pol, VP16 and gC, respectively. However, expression levels are low for VP16 and even lower for the gC, such that IE180 is unable to fully substitute for ICP4 functionally. Viral progeny was not detected in PK15 cells expressing PRV IE180.

Cross-sectional study of the prevalence, causes and management of hospital-onset diarrhoea

BACKGROUND

The National Health Service in England advises hospitals collect data on hospital-onset diarrhoea (HOD). Contemporaneous data on HOD are lacking.

AIM

To investigate prevalence, aetiology and management of HOD on medical, surgical and elderly-care wards.

METHODS

A cross-sectional study in a volunteer sample of UK hospitals, which collected data on one winter and one summer day in 2016. Patients admitted ≥72 h were screened for HOD (definition: ≥2 episodes of Bristol Stool Type 5-7 the day before the study, with diarrhoea onset >48 h after admission). Data on HOD aetiology and management were collected prospectively.

FINDINGS

Data were collected on 141 wards in 32 hospitals (16 acute, 16 teaching). Point-prevalence of HOD was 4.5% (230/5142 patients; 95% confidence interval (CI) 3.9-5.0%). Teaching hospital HOD prevalence (5.9%, 95% CI 5.1-6.9%) was twice that of acute hospitals (2.8%, 95% CI 2.1-3.5%; odds ratio 2.2, 95% CI 1.7-3.0). At least one potential cause was identified in 222/230 patients (97%): 107 (47%) had a relevant underlying condition, 125 (54%) were taking antimicrobials, and 195 (85%) other medication known to cause diarrhoea. Nine of 75 tested patients were Clostridium difficile toxin positive (4%). Eighty (35%) patients had a documented medical assessment of diarrhoea. Documentation of HOD in medical notes correlated with testing for C. difficile (78% of those tested vs 38% not tested, P<0.001). One-hundred and forty-four (63%) patients were not isolated following diarrhoea onset.

CONCLUSION

HOD is a prevalent symptom affecting thousands of patients across the UK health system each day. Most patients had multiple potential causes of HOD, mainly iatrogenic, but only a third had medical assessment. Most were not tested for C. difficile and were not isolated.

Expression of the immediate early IE180 protein under the control of the hTERT and CEA tumor-specific promoters in recombinant pseudorabies viruses: Effects of IE180 protein on promoter activity and apoptosis induction

Since the pseudorabies virus (PRV) genome encodes for a single immediate-early protein, IE180, we reasoned that this strong transactivating protein could represent a key regulatory switch that could be genetically manipulated in order to alter its tropism towards cancer cells. We therefore initiated studies to test whether the human telomerase reverse transcriptase (hTERT) and carcinoembryonic antigen (CEA) tumor promoters could functionally replace the IE180 promoter. We show that both promoters can functionally substitute the IE180 promoter in plasmid constructs and recombinant viruses, and observed that IE180 differentially auto-regulated each promoter tested, with PRV IE180 negatively regulating the hTERT promoter but positively hyper-activating the CEA promoter. Interestingly, we also observed that the recombinant PRV-TER and PRV-CEA viruses preferentially replicated in diverse cancer cell lines compared to control non-cancer cells, and the PRV-CEA was capable of additionally inducing a profound apoptotic phenotype which we correlated to the overexpression of IE180.

Infectious delivery and long-term persistence of transgene expression in the brain by a 135-kb iBAC-FXN genomic DNA expression vector

Novel gene-based therapies for disease will depend in many cases on long-term persistent transgene expression. To develop gene therapy strategies for Friedreich's ataxia (FRDA), we have examined the persistence of transgene expression in the brain in vivo provided by the entire 135 kb FXN genomic DNA locus delivered as an infectious bacterial artificial chromosome (iBAC) herpes simplex virus type 1 (HSV-1)-based vector injected in the adult mouse cerebellum. We constructed genomic DNA-reporter fusion vectors carrying a complete 135 kb FXN genomic locus with an insertion of the Escherichia coli lacZ gene at the ATG start codon (iBAC-FXN-lacZ). SHSY5Y human neuroblastoma cells transduced by iBAC-FXN-lacZ showed high efficiency of vector delivery and LacZ expression. Direct intracranial injection of iBAC-FXN-lacZ into the adult mouse cerebellum resulted in a large number of easily detectable transduced cells, with LacZ expression driven by the FXN genomic locus, which persisted for at least 75 days. Green fluorescent protein expression driven from the same vector but by the strong HSV-1 IE4/5 promoter was transient. Our data demonstrate for the first time sustained transgene expression in vivo by infectious delivery of a genomic DNA locus >100 kb in size. Such an approach may be suitable for gene rescue strategies in neurological disease, such as FRDA.

Construction and properties of a recombinant pseudorabies virus with tetracycline-regulated control of immediate-early gene expression

A study was carried out to determine whether altering the control of expression of the IE180 gene of pseudorabies virus (PRV), by replacing the IE180 promoter with the tetracycline-responsive promoter (Ptet), affects virus replication and virulence. This PRV-BT90 mutant virus was constructed by complementation and recombination in Hela Tet-Off cells. The virus yield produced by infection of Hela Tet-Off cells with PRV-BT90 was similar to that of the parental virus vBecker2. Viral replication of PRV-BT90 was reduced in Vero cells as reflected by a reduction of virus yield and plating efficiency compared to vBecker2. PRV-BT90 plaque formation in Hela Tet-Off cells was inhibited in the presence of doxycycline, whereas vBecker2 plaque formation was not affected. Subcutaneous infection of mice with the two viruses revealed a LD(50) higher than 10(6) TCID(50) for the PRV-BT90 mutant virus while the LD(50) was 178 TCID(50) for the vBecker2 parental virus.

Spontaneous coronary artery dissection presenting as an ischaemic stroke in a middle-aged man with anti-cardiolipin antibodies: a case report

Introduction

Cerebrovascular disease is a major cause of mortality and morbidity worldwide. Ischemic stroke is the most common manifestation, encompassing a wide variety of causative mechanisms. We present the case of a middle-aged male patient with spontaneous coronary artery dissection in the presence of anti-cardiolipin antibodies, leading to left ventricular thrombus and presenting with stroke.

Case presentation

A 56-year-old Caucasian man presented with dysarthria and right-sided weakness. There was a history of chest pain with autonomic symptoms four days earlier. Examination revealed right-sided hemiparesis. Electrocardiogram showed sinus rhythm with anterior Q waves. Magnetic resonance imaging of the brain showed large left parietal and smaller multiple cerebral infarcts. Echocardiogram showed anterior wall and apical akinesis with a large mural thrombus. Anti-cardiolipin antibodies immunoglobulin G and immunoglobulin M were strongly positive. Coronary angiography showed dissection of the mid left anterior descending artery with normal flow down the distal vessel. He was treated conservatively with anticoagulation and secondary prevention. He was in good health when seen in clinic four months later.

Conclusion

We highlight the importance of a comprehensive approach at obtaining the correct diagnosis, input of different specialities and the fact that the presence of anti-cardiolipin antibodies is associated with coronary artery dissection in a middle-aged male patient whose presentation was stroke.

Overview of gene delivery into cells using HSV-1-based vectors

This overview describes the considerations involved in the preparation and use of herpes simplex virus type 1 (HSV-1) as a vector for gene transfer into neurons. Strategies for gene delivery into neurons, either to study the molecular biology of brain function or for gene therapy, must utilize vectors that persist stably in postmitotic cells and that can be targeted both spatially and temporally in the nervous system in vivo. This unit describes the biology of HSV-1 along with a discussion covering development of amplicon and genomic HSV-1 vectors. Advantages and disadvantages of current HSV-1 vectors are presented, and HSV-1 vectors are compared with other vectors for gene transfer into neurons.

Generation of high-titer defective HSV-1 vectors

There are two types of replication-deficient herpes simplex virus type 1 (HSV-1) vectors: those in which the foreign DNA of interest is cloned into the viral genome itself, and those that are comprised of a plasmid (amplicon) carrying minimal HSV-1 sequences that allow it to be packaged into virus particles with the aid of a helper virus. This unit describes the generation of helper virus stocks. Preparation of recombinant amplicon vector particles by transfection of amplicon and superinfection of helper virus into cells, and harvesting of packaged particles, is also delineated. Thorough characterization of the viral vector stock involves measuring (1) the helper virus plaque-forming units per ml (pfu/ml) on 2-2 cells, (2) the wild-type HSV-1 pfu/ml on Vero cells, and (3) the amplicon stock infectious vector units per ml (ivu/ml) on PC12 cells. Support protocols detail methods for determining titers of helper virus and wild-type virus by plaque assay, and of amplicon stocks by vector assay.

Secondary infertility as a late complication of vesico-amniotic shunt therapy

OBJECTIVE

Vesico-amniotic shunting can be used for the treatment of fetal obstructive uropathy. However, the procedure is associated with a significant risk of complications. We report a case of a complicated vesico-amniotic placement, where a vesico-amniotic shunt ultimately resulted in, fortunately reversible, infertility.

CASE

A 36-year-old multigravida was referred to our center at 13 weeks' gestation for the evaluation of fetal lower urinary obstruction. A vesico-amniotic shunt placement requiring several attempts was performed. A few weeks later premature rupture of the membranes occurred. At the request of the parents, the pregnancy was terminated at 22 weeks'gestation. The patient visited us again for secondary infertility, which turned out to be caused by a shunt left behind in the uterus, acting as an IUD. After hysteroscopic removal, she soon became pregnant again.

CONCLUSION

This case illustrates the importance of careful documentation relating to each and every operation, of all materials used and what was retained in the patient. At delivery, obstetric staff should be completely aware of the prenatal treatment procedures performed, to ensure that no foreign objects are left by oversight, inside the patient's body.

Repair of acute Achilles tendon rupture using a double-ended needle

PURPOSE

To compare the results of Achilles tendon repair using a standard open procedure or a minimally invasive technique using a double-ended needle, and to determine whether the latter technique reduces the incidence of sural nerve injury and soft-tissue complications.

METHODS

Between the period February 1995 and September 2000 inclusive, 68 consecutive patients with acute Achilles tendon rupture underwent surgical repair in our hospitals. A standard open repair was performed on 43 patients (mean age 36 years and range 17-74 years, 30 males), while 25 patients (mean age 34 years and range 19-68 years, 17 males) elected to undergo the minimally invasive procedure involving a double-ended needle. Postoperative protocols were identical for the 2 groups. Patients were assessed for re-rupture, calf muscle strength, calf atrophy, wound healing, and ability to return to pre-injury activity. The mean follow-up period was 65.5 (range, 34-90) months.

RESULTS

One late re-rupture and one sural nerve injury occurred in the standard open repair group. No rerupture or sural nerve injury occurred in those having minimally invasive surgery, they also reported fewer complications related to wound healing and a shorter hospital stay. Calf atrophy was also significantly less in this group (p<0.05).

CONCLUSION

This double-ended needle repair technique is simple and reproducible. The needle is easy to make using a standard mini Steinmann pin with minimal cost. Combined with appropriate rehabilitation, the technique achieves good results and is associated with a low morbidity and complications.

Early results of modified fludarabine, cyclophosphamide, and rituximab (mFCR) for patients with previously untreated advanced chronic lymphocytic leukemia (CLL)

6599

Background: Recent data reporting results of FCR therapy in previously untreated advanced CLL patients (F-25 mg/m2 d1–3 q 4wk; C-250 mg/m2 d 1–3 q 4wk; R-500 mg/m2 d1 q 4wk for 6 cycles) demonstrated complete remission (CR) of 70% and overall response (OR) of 95% (J Clin Oncol 2005;23:4079). The major toxicity was grade 3/4 neutropenia during 52% of courses. One approach to decrease neutropenia without compromising efficacy could be by reducing the doses of F and C and increasing the dose of R as high-dose R has been reported to be more efficacious in CLL. Methods: We conducted a phase II study for previously untreated advanced CLL patients treated with mFCR (F-20mg/m2 d1–3 q 4 wk; C-150 mg/m2 d1–3 q 4 wk; R-500mg/m2 d1 and d14 q 4wks; maintenance R-500 mg/m2 q 3 months until progression). A Simon two-stage design was used where 15 patients were accrued in the first stage and because of acceptable toxicity and response rate in stage I an additional 35 patients will be treated. The primary endpoint was response rate. Results: Twenty patients (13 male, 7 female), age 36–85 years (median 59) were treated with a total of 105 mFCR courses. All 20 patients were evaluable for toxicity. Grade 3/4 neutropenia occurred during 11(10.5%) courses. There were no episodes of neutropenic fever. Grade 3/4 thrombocytopenia occurred during 4 (3.8%) courses. Two patients are currently on study and not evaluable for response and among the 18 evaluable patients, the CR was 68%, PR was 32% with an OR of 100%. Eleven of the 12 CR patients had no evidence of CD5+/CD19+ coexpressing cells in their bone marrow after therapy and one had <1%; all 12 were NED by CT scan. Conclusions: Our preliminary results suggest mFCR is highly effective with considerably less grade 3/4 neutropenia than standard FCR. Complete responders had minimal residual disease in their bone marrow following mFCR.

[Table: see text]

Characterization of a double (amyloid precursor protein-tau) transgenic: tau phosphorylation and aggregation

A double transgenic mouse expressing the amyloid precursor protein, bearing the Swedish mutations, and expressing tau protein containing three of the mutations present in frontotemporal dementia linked to chromosome 17 (FTDP-17), has been characterized. In the double transgenic mouse an increase in tau phosphorylation at serine S262 and S422 was observed compared with that found in simple transgenic mice. The phosphorylation at S262 was also found, in a much lower level, in the single transgenic mouse expressing amyloid precursor protein (APP), and it was absent in that overexpressing tau variant. Additionally, in the double transgenic mouse a slight increase in the amount of sarkosyl insoluble tau polymers was observed in comparison with that found in single transgenic tau mouse. Also, wider tau filaments were found in the double transgenic mouse compared with those found in the single transgenic mouse. Our results suggest that beta-amyloid peptide could facilitate the phosphorylation of tau at a site not directed by proline, such as serine 262, and that modification could facilitate tau aberrant aggregation. Also, they suggest that different types of tau filamentous polymers can occur in different mouse models for tauopathies, like those used for Alzheimer's disease or FTDP-17.

An Ashkenazi Jewish woman presenting with favism

The case of a 44 year old Ashkenazi Jewish woman of Russian origin who presented with a typical clinical and haematological picture of favism is reported. There was initial difficulty in confirming glucose-6-phosphate dehydrogenase (G6PD) deficiency because the enzyme concentrations were normal at presentation, but later fell to a concentration compatible with heterozygosity for the Mediterranean type of G6PD deficiency. The diagnosis was also later confirmed by gene analysis. The reasons for the difficulties in the initial confirmation of the diagnosis and the normal G6PD enzyme activity at presentation are discussed.

Tau in neurodegenerative diseases: tau phosphorylation and assembly

The possible link between tau phosphorylation and tau assembly in these neurodegenerative diseases known as tauopathies is described. Additionally, this link is supported by an in vitro experiment showing the higher capacity of phosphotau to assemble in some specific conditions; and, by a recently reported experiment using a tau transgenic mouse model.

FTDP-17 mutations in tau transgenic mice provoke lysosomal abnormalities and Tau filaments in forebrain

The tauopathies, which include Alzheimer's disease (AD) and frontotemporal dementias, are a group of neurodegenerative disorders characterized by filamentous Tau aggregates. That Tau dysfunction can cause neurodegeneration is indicated by pathogenic tau mutations in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17). To investigate how Tau alterations provoke neurodegeneration we generated transgenic mice expressing human Tau with four tubulin-binding repeats (increased by FTDP-17 splice donor mutations) and three FTDP-17 missense mutations: G272V, P301L, and R406W. Ultrastructural analysis of mutant Tau-positive neurons revealed a pretangle appearance, with filaments of Tau and increased numbers of lysosomes displaying aberrant morphology similar to those found in AD. Lysosomal alterations were confirmed by activity analysis of the marker acid phosphatase, which was increased in both transgenic mice and transfected neuroblastoma cells. Our results show that Tau modifications can provoke lysosomal aberrations and suggest that this may be a cause of neurodegeneration in tauopathies.

Foot-and-mouth disease virus lacking the VP1 G-H loop: the mutant spectrum uncovers interactions among antigenic sites for fitness gain

The Arg-Gly-Asp (RGD) triplet found in the G-H loop of capsid protein VP1 of foot-and-mouth disease virus (FMDV) is critically involved in the interaction of FMDV with integrin receptors and with neutralizing antibodies. Multiplication of FMDV C-S8c1 in baby hamster kidney 21 (BHK-21) cells selected variant viruses exploiting alternative mechanisms of cell recognition that rendered the RGD integrin-binding triplet dispensable for infectivity. By constructing chimeric viruses, we show that dispensability of the RGD in these variant FMDVs can be extended to surrounding amino acid residues. Replacement of eight amino acid residues within the G-H loop of VP1 by an unrelated FLAG marker yielded infectious virus. Evolution of FLAG-containing viruses in BHK-21 cells generated complex quasispecies in which individual mutants included amino acid replacements at other antigenic sites of FMDV. Inclusion of such replacements in the parental FLAG clone resulted in an increase of relative fitness of the viruses. These results suggest structural or functional connections between antigenic sites of FMDV and underscore the value of mutant spectrum analysis for the identification of fitness-promoting genetic modifications in viral populations. The possibility of producing viable viruses lacking antigenic site A may find application in the design of new anti-FMD vaccines.

Integrating retroviral cassette extends gene delivery of HSV-1 expression vectors to dividing cells

Retroviral vectors have long been used in a wide variety of gene transfer applications but have certain drawbacks, such as small cargo size, limited tropism, and low titers. HSV expression vectors overcome these disadvantages, but, because they persist in target cells as nonreplicative episomes, they are not retained in all the progeny of dividing cells. Chimeric HSV/AAV products that can mediate transgene integration in human mitotic cells have been constructed, but, to date, genetic modification of dividing cells in animal models using HSV products has not been possible. Here, we report the construction of hybrid HSV/retroviral vectors that exhibit up to 50-fold higher transgene integration efficiency compared to vectors containing only HSV-1 components. Efficient integration of a retroviral transgene cassette encoding pac in human cells required expression of the Moloney murine leukemia virus gag-pol genes, but in murine cells, could also be mediated by endogenous activities, albeit at a lower level. Gene delivery was equally efficient in BHK21, a cell line resistant to retroviral infection, and transgene retention and expression were observed to be stable for least one month in Hs683 human glioma cells. These vectors have wide applications for the genetic modification of many cell types.

The inhibition of phosphatidylinositol-3-kinase induces neurite retraction and activates GSK3

It has been extensively described that neuronal differentiation involves the signalling through neurotrophin receptors to a Ras-dependent mitogen-activated protein kinase (MAPK) cascade. However, signalling pathways from other neuritogenic factors have not been well established. It has been reported that cAMP may activate protein kinase (PKA), and it has been shown that PKA-mediated stimulation of MAPK pathway regulates not only neuritogenesis but also survival. However, extracellular regulated kinases (ERKs) mediated pathways are not sufficient to explain all the processes which occur in neuronal differentiation. Our present data show that: in cAMP-mediated neuritogenesis, using the SH-SY5Y human neuroblastoma cell line, there exists a link between the activation of PKA and stimulation of phosphatidylinositol 3-kinase (PI3K). Both kinase activities are essential to the initial elongation steps. Surprisingly, this neuritogenic process appears to be independent of ERKs. While the activity of PI3K is essential for elongation and maintenance of neurites, its inhibition causes retraction. In this neurite retraction process, GSK3 is activated. Using both a pharmacological approach and gene transfer of a dominant negative form of GSK3, we conclude that this induced retraction is a GSK3-dependent process which in turn appears to be a common target for transduction pathways involved in lysophosphatidic acid-mediated and PI3K-mediated neurite retraction.

Translational repression and specific RNA binding by the coat protein of the Pseudomonas phage PP7

PP7 is a single-strand RNA bacteriophage of Pseudomonas aeroginosa and a distant relative to coliphages like MS2 and Qbeta. Here we show that PP7 coat protein is a specific RNA-binding protein, capable of repressing the translation of sequences fused to the translation initiation region of PP7 replicase. Its RNA binding activity is specific since it represses the translational operator of PP7, but does not repress the operators of the MS2 or Qbeta phages. Conditions for the purification of coat protein and for the reconstitution of its RNA binding activity from disaggregated virus-like particles were established. Its dissociation constant for PP7 operator RNA in vitro was determined to be about 1 nm. Using a genetic system in which coat protein represses translation of a replicase-beta-galactosidase fusion protein, amino acid residues important for binding of PP7 RNA were identified.