Multiscale homogenisation of diffusion in enzymatically-calcified hydrogels

Hydrogels are a promising class of material in biomedical and industrial applications, where both the mechanical and diffusion properties play an important role. The wide range of polymers that can be used and the different production methods allows these properties to be specifically tuned to a high degree for their application. Producing tough hydrogels with high stiffness has been a long-standing challenge that has recently been addressed by mineralisation methods. Those methods modify the hydrogel into one with a supporting mineral microstructure that is highly heterogeneous. This work investigates methods to determine the macroscopic diffusion behaviour of heterogeneous gels by a homogenisation method implemented in a finite element framework. This is applied to two recently developed materials by calcifying poly-dimethyl-acrylamide (PDMA) and polyacrylamide hydrogels (PAAm). The former has porous, spherical inclusions obstructing diffusion, while the latter has spherical pores enabling it. For both gels the unobstructed volume can be used as the primary parameter to tune the diffusivity. In PDMA the porosity of the obstructions is shown by multiscale analysis to give a strong, non-linear dependence of the diffusivity on the solute molecule radius. The framework is extended to other materials and comparisons are made to experimental works from the literature.

Cryptococcal laryngitis in an immunocompetent asthmatic patient using inhaled corticosteroids

We present a case of laryngeal cryptococcosis caused by cryptococcosis neoformans var. grubii affecting a patient using excessive inhaled corticosteroids. The patient experienced symptoms for several months prior to specialist review and the visualization of a mass lesion by nasopharyngoscopy. Fortunately a biopsy was performed and through histopathology & microbiological assessment a diagnosis of cryptococcal laryngitis was made. Treatment with 6 months of fluconazole resulted in clinical cure and resolution of symptoms. It is important to raise awareness of the risk of non-Candida fungal infections in patients on high dose corticosteroids, especially in the post covid era were steroids are more commonly prescribed.

183 DEVELOPING AND FACILITATING ONLINE INTERGENERATIONAL CAFÉS

Background

Many older people throughout their lives will require nursing care, consequentially most nurses will care for older people during their career. It is important that older people and student nurses are provided with shared learning opportunities so that professional caring partnerships can be nurtured and realised for mutual benefit. Intergenerational projects offer opportunities for intergenerational learning. However, few projects explore student nurse-older person dyads and how these can be integrated within undergraduate pre-registration programmes. This paper describes the development and facilitation of online older person-student nurse intergenerational cafés.

Methods

The project was managed by a design team comprising senior administration, lecturers in BSc Nursing programmes and a lecturer in Design for Health and Wellbeing. The ‘world café’ concept along with values of enablement and participation underpinned the design. The initiative was planned to align with a year three community care module. Regular online team meetings were held to agree the aims and outcomes for student nurse-older person cohorts, decide recruitment strategies, agree the process and format of facilitation. Older people were recruited through retirement, church, volunteer, social and sporting organisations, media and also using snowballing methods.

Results

Both student nurse and older person cohorts were offered support on how to access and participate in the café. Participants attended one of three online cafés hosted through Microsoft Teams. Each café followed the same format: 1) Group meeting convened with all participants; 2) Breakout small group ‘table’ discussions with student nurse-older people participants and design team facilitation; 3) The café was reconvened to whole group meeting where feedback was collated to elicit shared learning.

Conclusion

The initiative proved successful and there is merit in embedding intergenerational cafés into professionally accredited health care programmes. Through sharing life experiences and perspectives, intergenerational barriers can be reduced and new insights developed on person-centred gerontological care.

NSW Cannabis Medicines Advisory Service preliminary survey results - Enquirer perceptions and patient outcomes

Background

In 2018, an innovative, State government‐funded cannabis medicines drug information service was established for health professionals in New South Wales (NSW). The NSW Cannabis Medicines Advisory Service (CMAS) provides expert clinical guidance and support to medical practitioners considering prescribing a cannabis medicine to their patient(s).

Aims

This research examines quality assurance and patient outcomes related to enquirers' experience with NSW CMAS.

Methods

Data collection involved an online, anonymous survey with two components. Following a health professional enquiry, quality assurance data were collected about the enquirers' experience with NSW CMAS. The second survey focussed on patient outcomes and provides real‐world observational data about cannabis medicines safety and effectiveness across a wide range of indications.

Results

Data collection occurred between January 2020 and June 2021. Preliminary analyses were based on 68 quality assurance and 50 patient outcomes survey responses. General practitioners represented the highest proportion of survey responses (n = 33; 49%). The most common enquiry involved ‘patient‐specific advice’ (n = 50; 74%). Patient‐specific information provided by the service was mainly used for prescribing decision support (n = 45; 90%).

Conclusions

Preliminary findings highlight the impact of an innovative cannabis medicines drug information service in supporting health professional clinical practice in an area of rapid knowledge translation. Quality assurance data indicate that the service is perceived well by the majority of enquirers. Patient outcomes data across a wide range of indications suggest some effectiveness and a reasonable safety profile for prescribed cannabis medicines for most patients.

Trends in cardiovascular mortality of cancer patients in the US over two decades 1999–2019

Background

Cancer is the second most common cause of death globally after cardiovascular (CV) disease. The present study sought to compare the trends in CV mortality between patients with and without cancer in the US over two decades (1999 to 2019), stratified by sociodemographic factors such as age, sex and geographical location.

Methods

In this retrospective study, the number of deaths, crude- and age-adjusted mortality rates between January 1, 1999, and December 31, 2019, were obtained from the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) data set

Results

We examined a total of 53,422,612 deaths between 1999 and 2019; of which 33.4% were defined as CV mortality and 25.6% had malignancy. During this period, among patients with cancer, the age-adjusted mortality rate dropped by 52%. (Vs, 38% in patients with no malignancy). CV mortality was highest in patients with gastrointestinal and prostate malignancy where CV mortality accounts together for over 40% of all CV mortality in patients with cancer in 1999 and 33.6% in 2019. The age-adjusted CV mortality rate (per 100,000 people) of patients with GI and prostate cancer nearly halved over twenty years from 2.7 to 1.0 and 2.5 to 1.0.

The CV age-adjusted mortality rate dropped more significantly among patients with gastrointestinal, breast, and prostate malignancy than among patients with hematological malignancy (59–63% vs. 41%. We observed that crude CV mortality rates amongst patients with cancer declined over the study period in all age groups but was more prominent among patients over 65 years old than those aged 55–64 and under 55 (51%-55% Vs. 41%, 25%, respectively).Similar reductions in mortality in men and women (54% and 53% reduction) were observed

During the study period the decline in cardiovascular mortality was more prominent in metro areas which led to lower age adjusted CV mortality in Metro compared to non-Metro areas (5.7–6.3 vs 7.2). The decline in age adjusted CV mortality in patients with cancer differed significantly in different states

Conclusions

In our temporal analysis we show a 50% decline in CV mortality in the US over two decades in both male and female patients with cancer, that has exceeded the reduction in CV mortality seen in the non-cancer population. The greatest reductions in CV mortality were observed in patients with GI, breast and prostate malignancies, those residing in metro areas and in patients aged 65 and over.

Funding Acknowledgement

Type of funding sources: None. CV death among cancer patients

Sugar prevalence in Aedes albopictus differs by habitat, sex and time of day on Masig Island, Torres Strait, Australia

Background

Sugar feeding is a fundamental behaviour of many mosquito species. For Aedes albopictus, an important vector of dengue virus and chikungunya virus, little is known about its sugar-feeding behaviour, and no studies have been conducted on this in the southern hemisphere. This knowledge is pivotal for determining the potential of attractive targeted sugar baits (ATSBs) to control this important vector.

Methods

The prevalence of sugar was assessed in 1808 Ae. albopictus from Masig Island, Torres Strait, Australia collected between 13 and 25 March 2020. Fructose presence and content in field-collected Ae. albopictus were quantified using the cold anthrone assay.

Results

Significantly more male (35.8%) than female (28.4%) Ae. albopictus were sugar fed. There was a significant interaction between sex and time of day on the probability of capturing sugar-fed Ae. albopictus. For both sexes, fructose prevalence and content were higher in mosquitoes caught in the morning than in the afternoon. Female Ae. albopictus collected in the residential habitat were significantly more likely to be sugar fed than those collected in the woodland habitat.

Conclusions

These findings provide baseline information about the sugar-feeding patterns of Ae. albopictus and provide essential information to enable an assessment of the potential of ATSBs for vector suppression and control on Masig Island, with relevance to other locations where this species occurs.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-05020-w.

Longitudinal evaluation of laboratory-based serological assays for SARS-CoV-2 antibody detection

Serological assays for SARS-CoV-2 infection are now widely available for use in diagnostic laboratories. Limited data are available on the performance characteristics in different settings, and at time periods remote from the initial infection. Validation of the Abbott (Architect SARS-CoV-2 IgG), DiaSorin (Liaison SARS-CoV-2 S1/S2 IgG) and Roche (Cobas Elecsys Anti-SARS-CoV-2) assays was undertaken utilising 217 serum samples from 131 participants up to 7 months following COVID-19 infection. The Abbott and DiaSorin assays were implemented into routine laboratory workflow, with outcomes reported for 2764 clinical specimens. Sensitivity and specificity were concordant with the range reported by the manufacturers for all assays. Sensitivity across the convalescent period was highest for the Roche at 95.2-100% (95% CI 81.0-100%), then the DiaSorin at 88.1-100% (95% CI 76.0-100%), followed by the Abbott 68.2-100% (95% CI 53.4-100%). Sensitivity of the Abbott assay fell from approximately 5 months; on this assay paired serum samples for 45 participants showed a significant drop in the signal-to-cut-off ratio and 10 sero-reversion events. When used in clinical practice, all samples testing positive by both DiaSorin and Abbott assays were confirmed as true positive results. In this low prevalence setting, despite high laboratory specificity, the positive predictive value of a single positive assay was low. Comprehensive validation of serological assays is necessary to determine the optimal assay for each diagnostic setting. In this low prevalence setting we found implementation of two assays with different antibody targets maximised sensitivity and specificity, with confirmatory testing necessary for any sample which was positive in only one assay.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

The SLAC RCE Platform for ProtoDUNE

The ProtoDUNE-SP is a single-phase liquid argon time projection chamber (LArTPC) prototype for the Deep Underground Neutrino Experiment (DUNE). Signals from 15,360 electronic channels are received by 60 Reconfigurable Cluster Elements (RCEs), which are processing elements designed at SLAC for a wide range of applications and are based upon the “system-onchip” Xilinx Zynq family of FPGAs. The RCEs are housed in industry-standard ATCA shelves on a custom blade, called the Cluster on Board (COB). The RCE platform and its processing functions for the ProtoDUNE-SP will be presented.

A comparison of four risk models for the prediction of cardiovascular complications in patients with a history of atrial fibrillation undergoing non-cardiac surgery

It is unclear how best to predict peri-operative cardiovascular risk in patients with atrial fibrillation undergoing non-cardiac surgery. This study examined the accuracy of the revised cardiac risk index and three atrial fibrillation thrombo-embolic risk models for predicting 30-day cardiovascular events after non-cardiac surgery in patients with a pre-operative history of atrial fibrillation. We conducted a prospective cohort study in 28 centres from 2007 to 2013 of 40,004 patients ≥ 45 years of age undergoing inpatient non-cardiac surgery who were followed until 30 days after surgery for cardiovascular events (defined as myocardial injury, heart failure, stroke, resuscitated cardiac arrest or cardiovascular death). The 2088 patients with a pre-operative history of atrial fibrillation were at higher risk of peri-operative cardiovascular events compared with the 34,830 patients without a history of atrial fibrillation (29% vs. 13%, respectively, adjusted odds ratio 1.30 (95%CI 1.17-1.45). Compared with the revised cardiac risk index (c-index 0.60), all atrial fibrillation thrombo-embolic risk scores were significantly better at predicting peri-operative cardiovascular events: CHADS₂ (c-index 0.62); CHA₂ DS₂ -VASc (c-index 0.63); and R₂ CHADS₂ (c-index 0.65), respectively. Although the three thrombo-embolic risk prediction models were significantly better than the revised cardiac risk index for prediction of peri-operative cardiovascular events, none of the four models exhibited strong discrimination metrics. There remains a need to develop a better peri-operative risk prediction model.

Lesion distribution in cases of canine atopic dermatitis in South Australia

OBJECTIVE

To determine the lesion distribution patterns in different breeds of dogs affected by atopic dermatitis in South Australia.

METHODS

The presence or absence of erythematous skin lesions in 267 cases of canine atopic dermatitis (CAD) was recorded across 36 anatomical sites. Breeds represented by ≥ 9 dogs were included in the analysis. The percentage of dogs showing lesions at each of the body sites was calculated and illustrated on colour-coded diagrams. Variations in affected body sites within and between breeds were compared using Kruskal-Wallis ANOVA and Dunn's multiple comparison tests.

RESULTS

The prevalence of skin lesions at different body sites differed significantly both in the population as a whole and within breeds. The sites affected in ≥ 75% dogs were the dorsal and ventral aspects of the front and hind paws. The sites affected in 50-74% were the medial pinnae, axillae, ventral chest, abdomen and perineum. Sites affected in 25-49% of dogs included the face, periocular region and forelimb. Remaining body sites were affected in < 25% of dogs. Analysis at the breed level revealed some differences from this standard distribution pattern.

CONCLUSION

The results of this study confirmed the typical lesion distributions seen in CAD and highlighted some subtle differences in breeds commonly seen in South Australia. This will be useful for clinical practitioners in prioritising differential diagnoses for pruritic skin conditions.

Septic pericarditis and pericardial abscess secondary to a migrating foreign body in a dog

Abscess formation in the pericardial space has been described as a rare complication of trauma, congenital defects, penetrating foreign body, or extension of local myocardial infection in the dog. Presented here is a case of a juvenile dog with septic pericardial effusion secondary to an isolated intrapericardial abscess. Surgical pericardiectomy was successful in removing the abscess and nidus for septic effusion in this patient, and histopathology of the abscess tissue was suggestive of foreign plant material migration as the nidus for abscess formation. Recheck echocardiogram at the six-month postoperative period showed no recurrence of pericardial effusion or abscessation. Although abscess formation and septic pericarditis secondary to foreign body migration is an uncommon cause for large volume pericardial effusion, this should be considered as a differential particularly in a young and previously healthy dog.

Nanoencapsulation of phase change materials for advanced thermal energy storage systems

Phase change materials (PCMs) allow the storage of large amounts of latent heat during phase transition. They have the potential to both increase the efficiency of renewable energies such as solar power through storage of excess energy, which can be used at times of peak demand; and to reduce overall energy demand through passive thermal regulation. 198.3 million tons of oil equivalent were used in the EU in 2013 for heating. However, bulk PCMs are not suitable for use without prior encapsulation. Encapsulation in a shell material provides benefits such as protection of the PCM from the external environment and increased specific surface area to improve heat transfer. This review highlights techniques for the encapsulation of both organic and inorganic PCMs, paying particular attention to nanoencapsulation (capsules with sizes <1 μm). We also provide insight on future research, which should focus on (i) the development of multifunctional shell materials to improve lifespan and thermal properties and (ii) advanced mass manufacturing techniques for the economically viable production of PCM capsules, making it possible to utilize waste heat in intelligent passive thermal regulation systems, employing controlled, "on demand" energy release/uptake.

PABPN1 gene therapy for oculopharyngeal muscular dystrophy

Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant, late-onset muscle disorder characterized by ptosis, swallowing difficulties, proximal limb weakness and nuclear aggregates in skeletal muscles. OPMD is caused by a trinucleotide repeat expansion in the PABPN1 gene that results in an N-terminal expanded polyalanine tract in polyA-binding protein nuclear 1 (PABPN1). Here we show that the treatment of a mouse model of OPMD with an adeno-associated virus-based gene therapy combining complete knockdown of endogenous PABPN1 and its replacement by a wild-type PABPN1 substantially reduces the amount of insoluble aggregates, decreases muscle fibrosis, reverts muscle strength to the level of healthy muscles and normalizes the muscle transcriptome. The efficacy of the combined treatment is further confirmed in cells derived from OPMD patients. These results pave the way towards a gene replacement approach for OPMD treatment.

Oculopharyngeal muscular dystrophy is caused by trinucleotide repeat expansions in the PABPN1 gene. Here the authors use AAV-based gene therapy to knockdown the mutant gene and replace it with a wild-type allele, and show effectiveness in mice and in patient cells.

Abstract OT3-04-01: BRE12-158: A phase II randomized controlled trial of genomically directed therapy after preoperative chemotherapy in patients with triple negative breast cancer (TNBC)

Background: About 1/3 of patients with TNBC who receive preoperative therapy will experience a pathological complete response (pCR). Patients with residual disease have a markedly inferior overall survival (OS) compared to those who experience pCR. Recently, the CREATE-X trial demonstrated an improvement in disease free survival (DFS) and OS for post-neoadjuvant capecitebine; although the addition of capecitebine to standard therapy has not previously improved outcome across other non-selected adjuvant or neo-adjuvant trials. Prior data have also demonstrated that the residual tumors are genomically diverse and that these genetic changes are reflected at time of relapse.

Trial Design: This trial is a randomized phase II trial to determine whether a genomically guided therapy in the setting of incomplete response to standard neoadjuvant therapy will improve outcomes compared to standard of care. DNA from archived tumor samples collected at the time of surgery will be extracted and sequenced. The sequencing data will be interrogated for known genomic drivers of sensitivity or resistance to existing FDA approved agents. A cancer genomic tumor board (CGTB) will consider the genomic data along with the patient's prior treatment history, toxicities, and comorbidities and select the optimal therapy. Participants with a CGTB recommendation will be randomized to Experimental Arm A (genomically directed monotherapy) or Control Arm B (standard of care). Participants may have no CGTB recommendation either because sequencing did not identify a matched drug or because the drug was contraindicated and will be assigned to Control Arm B.

Eligibility criteria: Patients must have histologically confirmed TNBC with completion of all definitive local therapy and no evidence of metastatic disease. There must be significant residual disease characterized by &gt;2cm primary tumor, or lymph node positivity or RCB classification II or III. An FFPE tumor block with tumor cellularity &gt;20% is required. All patients must have completed preoperative chemotherapy including a taxane or anthracycline or both.

Specific aims: The Primary Aim is to compare 2-year DFS with a genomically directed therapy vs. standard of care. Secondary Aims include 1-year DFS, 5-year OS, collection of archival specimens for correlative studies, and to describe toxicities. Exploratory Aims are to describe the evolution of genomically directed therapies during the course of the study and to evaluate the drug specific effect on efficacy and toxicity.

Statistical methods: In order to detect an improvement in the fraction of patients free from disease at 2-year from 40% in the control Arm B to 63.2% in the genomically directed Experimental Arm A (corresponding to an HR=0.5), 136 participants will have 80% power to detect a difference in DFS using a two-side log-rank test with 0.05 level of significance.

Present accrual/target accrual: 38 accrued of 136 to be randomized.

Citation Format: Schneider B, Miller KD, Badve S, O'Neil B, Helft P, Chitambar C, Falkson C, Nanda R, McCormick M, Danso M, Blaya M, Langdon R, Lippman M, Paplomata E, Walling R, Thompson M, Robin E, Aggarwal L, Shalaby I, Canfield V, Adesunloye B, Lee T, Daily K, Ma C, Erban J, Radhakrishnan N, Bruetman D, Graham M, Reddy NA, Lynce FC, Radovich M. BRE12-158: A phase II randomized controlled trial of genomically directed therapy after preoperative chemotherapy in patients with triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT3-04-01.

The prediction of postoperative stroke or death in patients with preoperative atrial fibrillation undergoing non-cardiac surgery: a VISION sub-study

BACKGROUND

The optimal means of pre-operative risk stratification in patients with atrial fibrillation (AF) is uncertain.

OBJECTIVE

To examine the accuracy of AF thromboembolic risk models (the CHADS2, CHA2DS2-VASc, and R2CHADS2 scores) for predicting 30-day stroke and/or all-cause mortality after non-cardiac surgery in patients with preoperative AF, and to compare these risk scores with the Revised Cardiac Risk Index (RCRI).

PATIENTS/METHODS

A multicentre (8 countries, 2007-2011) prospective cohort study of patients ≥ 45 years of age undergoing inpatient non-cardiac surgery, who were followed until 30 days after surgery. We calculated c-statistics for each risk prediction model and net reclassification improvements (NRIs) compared with the RCRI.

RESULTS

The 961 patients with preoperative AF were at higher risk of any cardiovascular event in the 30 days postoperatively compared with the 13 001 patients without AF: 26.6% vs. 9.0%; adjusted odds ratio, 1.58; 95% confidence interval [CI], 1.33-1.88. All thromboembolic risk scores predicted postoperative death just as well as the RCRI (with c-indices between 0.67 and 0.72). Compared with the RCRI (which had a c-index of 0.64 for 30-day stroke/death), the CHADS2 (c-index, 0.67; NRI, 0.31; 95% CI, 0.02-0.61) significantly improved postoperative stroke/mortality risk prediction, largely due to improved discrimination of patients who did not subsequently have an event.

CONCLUSIONS

In AF patients, the three thromboembolic risk scores performed similarly to the RCRI in predicting death within 30 days and the CHADS2 score was the best predictor of postoperative stroke/death regardless of type of surgery.

In vitro self-assembly of human pericyte-supported endothelial microvessels in three-dimensional coculture: a simple model for interrogating endothelial-pericyte interactions

We describe a method for coculture of macro- or microvascular human endothelial cells (ECs) and pericytes (PCs) within a 3-dimensional (3-D) protein matrix resulting in lumenized EC cords invested by PCs. To prevent apoptotic cell death of ECs in 3-D culture, human umbilical vein or dermal microvascular ECs were transduced to express the antiapoptotic protein Bcl-2. To prevent PC-mediated gel contraction, the collagen-fibronectin gel was polymerized within a polyglycolic acid nonwoven matrix. Over the first 24-48 h, EC-only gels spontaneously formed cords that developed lumens via vacuolization; such vascular networks were maintained for up to 7 days. In EC-PC cocultures, PCs were recruited to the EC networks. PC investment of EC cords both limited the lumen diameter and increased the degree of vascular network arborization. Peg and socket junctions formed between ECs and PCs in this system, but dye transfer, indicative of gap junction formation, was not observed. This simple system can be used to analyze bidirectional signals between ECs and PCs in a 3-D geometry.

Public health genomics and the new molecular epidemiology of bacterial pathogens

Laboratory methods that can unambiguously fingerprint pathogenic microbes are needed to investigate the transmission of human infectious diseases from diverse sources, such as from the community, from the environment, within hospitals, or from contaminated food or water sources. Public health investigations currently rely on laboratory subtyping methods that ultimately provide only a fraction of the total genetic information of a pathogen, and although there is widespread success using existing subtyping methods, they do not always provide sufficient evidence to link disease cases together into outbreaks or to link these human cases to the culprit source. Alternatively, whole-genome sequencing of bacterial pathogens provides an unabridged examination of the genetic content of individual pathogen isolates, enabling public health laboratories to benefit from comparative analyses of total genetic content. In this context, whole-genome sequencing represents the ultimate epidemiological typing method - a universally applicable, highly detailed typing platform capable of providing the entire genetic blueprint of a pathogen and distinguishing strains to the single nucleotide level. These new genomic methods, if implemented within existing public health laboratory response programs, promise to revolutionize the ability of the laboratory to provide information and evidence on the evolution, transmission and virulence for bacterial pathogens - and this revolution is launching the new field of 'genomicepidemiology'.

The isolation and identification of cis-diamminedichloroplatinum (ii)-DNA adducts by anion-exchange HPLC and inductively coupled plasma mass-spectrometry

The adducts produced by the reaction of cis-diamminedichloroplatinum(II) with DNA have previously been isolated and characterised. These adducts may be measured at the cellular level by immunochemical detection but the accuracy of this assay is dependent on the number of adducts per nucleotide. We have developed a novel assay for cisplatin-DNA adducts, utilising an established method in which platinated DNA is digested to form a mixture of nucleotides and adducts; these are then separated by anion exchange HPLC. The number of cisplatin-DNA adducts is determined by measurement of the platinum content of the HPLC fractions by inductively coupled plasma mass spectrometry. The assay has been validated by cochromatography of purified drug-DNA adducts whose identity has been confirmed by NMR. We describe an application of the assay, namely the measurement of in vitro removal of cisplatin-DNA adducts from calf thymus DNA by cell free extracts derived from tumour cell lines. Adduct removal is dependent on both the amount of extract protein and the duration of the reaction. Almost 70% of adducts are removed from 5mug of DNA (drug:nucleotide ratio 0.08) by 80mug of extract. Other potential applications of the assay are discussed.

Search for a new gauge boson in electron-nucleus fixed-target scattering by the APEX experiment

We present a search at the Jefferson Laboratory for new forces mediated by sub-GeV vector bosons with weak coupling α' to electrons. Such a particle A' can be produced in electron-nucleus fixed-target scattering and then decay to an e + e- pair, producing a narrow resonance in the QED trident spectrum. Using APEX test run data, we searched in the mass range 175-250 MeV, found no evidence for an A'→ e+ e- reaction, and set an upper limit of α'/α ~/= 10(-6). Our findings demonstrate that fixed-target searches can explore a new, wide, and important range of masses and couplings for sub-GeV forces.