265 results for Conference poster

  • Recent experiences in using TOUGH2 for geothermal modelling

    Clearwater, Emily; Yeh, Angus; O'Sullivan, John; Kaya, Eylem; Croucher, Adrian; Cui, T; OSullivan, Michael; Zarrouk, Sadiq; Austria, JJC; Ciriaco, Anthony; Archer, Rosalind; Dempsey, David (2012-04-17)

    Conference poster
    The University of Auckland Library

    The geothermal modelling group in Engineering Science (University of Auckland) is involved with several geothermal R&D projects. On the development side we are running models of Ohaaki, Wairakei, Ngawha, Reporoa, Wayang Windu and Lihir. Our experiences in these projects have led on to several parallel research projects. Our model of Wairakei-Tauhara is so large that it also contains the Rotokawa system and the edge of the Ngatamriki system. Trying to understand the large-scale convection process at Wairakei-Tauhara has led on to studies of more generic convection studies and studies of larger areas of the TVZ. It has also led on to deeper models which require equations of state that can handle high pressures and temperatures. We have developed one for pure water but now wish to extend it to include CO2 and NaCl. With larger and larger models the computational demand increases quickly and we are now routinely using TOUGH_MP, the parallel version of TOUGH2. Also with large complex models dealing with input and output is a major task and we have developed a suite of PYTHON scripts (called pyTOUGH) for carrying out several model management tasks. One of the biggest challenges in geothermal modelling is model calibration and we have carried out studies using inverse modelling with iTOUGH and PEST and also Markov Chain Monte Carlo methods (MCMC). We are also carrying out miscellaneous studies of resewrvoir physics several of which involve fluid/rock interaction, for example the effects of cold water injection on permeability and subsidence in geothermal fields.

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  • Coronary artery bifurcation haemodynamics - comparison between phase contrast MRI and computational fluid dynamics

    Beier, Susann; Ormiston, J; Webster, M; Cater, John; Medrano-Garcia, P; Young, Alistair; Cowan, Brett (2014-01-17)

    Conference poster
    The University of Auckland Library

    Coronary atherosclerosis is common at vessel bifurcations. A quantitative approach to measuring blood velocity, vorticity and more complex flow features at bifurcations would enhance the understanding of the mechanisms of atheroma development, and potentially predict vessels at highest risk. The aim of this work was to validate 4D phase contrast (PC) magnetic resonance imaging flow measurements using a simplified arterial model of the left main coronary bifurcation against computational fluid dynamic (CFD) modelling.

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  • A case of overwhelming sepsis in splenectomised child

    Alkhudairi, Z; Wilson, E; Best, Emma (2015-03-19)

    Conference poster
    The University of Auckland Library

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  • Reducing the Risks of Long-Term Human Space Exploration by Simulating Missions in an Analog Environment on Mauna Loa

    Binsted, K; Hunter, JB; Caldwell, Bryan (2012-02)

    Conference poster
    The University of Auckland Library

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  • Measuring the electrical impedance of mouse brain cortex

    Wilson, MT; Elbohouty, M; Lin, Oliver; Voss, LJ; Jones, K; Steyn-Ross, DA (2014)

    Conference poster
    The University of Auckland Library

    We report on an experimental method to measure conductivity of cortical tissue. We use a pair of 5mm diameter Ag/AgCl electrodes in a Perspex sandwich device that can be brought to a distance of 400 microns apart. The apparatus is brought to uniform temperature before use. Electrical impedance of a sample is measured across the frequency range 20 Hz-2.0 MHz with an Agilent 4980A four-point impedance monitor in a shielded room. The equipment has been used to measure the conductivity of mature mouse brain cortex in vitro. Slices 400 microns in thickness are prepared on a vibratome. Slices are bathed in artificial cerebrospinal fluid (ACSF) to keep them alive. Slices are removed from the ACSF and sections of cortical tissue approximately 2 mm times 2 mm are cut with a razor blade. The sections are photographed through a calibrated microscope to allow identification of their cross-sectional areas. Excess ACSF is removed from the sample and the sections places between the electrodes. The impedance is measured across the frequency range and electrical conductivity calculated. Results show two regions of dispersion. A low frequency region is evident below approximately 10 kHz, and a high frequency dispersion above this. Results at the higher frequencies show a good fit to the Cole-Cole model of impedance of biological tissue; this model consists of resistive and non-linear capacitive elements. Physically, these elements are likely to arise due to membrane polarization and migration of ions both intra- and extra-cellularly.

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  • Visual Acuity, Refractive Status and Accommodation in Octopus Gibbsi

    Tunrbull, P; Backhouse, Simon; Phillips, John (2010-07-27)

    Conference poster
    The University of Auckland Library

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  • Loop closure and kinase selectivity in lung cancer

    Yosaatmadja, Yuliana; Squire, Christopher (2016-07-17)

    Conference poster
    The University of Auckland Library

    Lung cancer is a leading cause of cancer deaths worldwide. Somatic mutations in tyrosine kinase receptors that causes aberrant signalling have been implicated in the development of lung cancer. Two such receptors, EGFR and FGFR kinases are directly involved in many cases of aggressive metastasis and drug resistance. The FGFR kinase family consists of four highly conserved receptor proteins (FGFR1 – FGFR4). FGFR pathways are the main cause of resistance to chemotherapy in non-small cell lung cancer patients, and 22% of them show over-expression of FGFR1. There are a number of small molecules in phase III clinical trials that target not only FGFR but also other kinases. A wide range of EGFR mutations are linked to lung cancer development in never-smokers or former smokers. The two most common mutations are exon 19 deletions and the point mutation L858R in exon 21. Many patients harbouring L858R acquire a secondary T790M mutation after treatment with gefitinib/erlotinib resulting in drug resistance. In the past few years AstraZeneca have developed drugs that target specific proteins, eg; AZD4547 (FGFR1 selective) and AZD9291 (selectivity for T790M/L858R EGFR). In an effort to design our own novel and selective inhibitors, we solved the structures of AZD4547 and AZD9291 in complex with FGFR and EGFR respectively. In both cases, the phosphate binding loop (P-loop) of the proteins forms an unusual “bent” structure wrapped closely around these inhibitors. We speculate that the ability of these compounds to induce P-loop closure is an important part of their respective selectivity mechanisms.

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  • Diphthong trajectories in Māori

    King, J; Watson, Catherine; Maclagan, M; Keegan, Peter; Harlow, R (2014-12-03)

    Conference poster
    The University of Auckland Library

    Sound change over time has been identified in monophthongs in Māori, the language of the indigenous people of NZ [1], with /u u:/ fronting, the mid vowels rising, so that /i~i:~e~e:/ can appear identical, and the quantitative distinctions between long and short monophthongs being reduced apart from /a~a:/ [1], [2]. The five most frequent diphthongs in Māori are /ai ae au ou ao/. Analysis has shown mergers between two pairs of these diphthongs, /ai~ae/ and /au~ou/ [3]. This study argued that only one of these mergers is due to the monophthong movements: we have shown that /e e:/ have risen [3], but the second target of /ae/ is falling. It was suggested that this merger is due to glide weakening of /ai/. The merger of /au/ and /ou/ is probably influenced by the fronting of /u u:/. The major distinction for /au ou/ is in the first target, but the fronting of T1 for both /au/ and /ou/ is highly correlated both to the fronting of T2, and the fronting of /u u:/ [3]. Diphthong analysis to date has only offered schematic formant trajectories with arrows from T1 to T2 indicating the movement [2], [3]. Here we present for the first time an analysis of the vowel mergers looking at the entire diphthong trajectories, for T1 and T2 for the male speakers. These plots reveal the course and timing of the diphthong movements.

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  • An optimal sampling schedule for neonates, infants & children receiving cefazolin +/- vancomycin for cardiopulmonary bypass

    Sturge, Jacqueline; Anderson, Brian; Holford, Nicholas (2016-08-22)

    Conference poster
    The University of Auckland Library

    Background: Dosing of prophylactic antibiotics in children during cardiopulmonary bypass (CPB) remains poorly defined. Pharmacokinetic (PK) studies can be improved using optimal design when sampling is limited, or multiple factors influence PK. We aimed to optimize a sampling schedule designed to determine cefazolin and vancomycin PK in children undergoing CPB. Methods: A one compartment distribution model for vancomycin and a three compartment distribution model for cefazolin was used with theory based allometric scaling and maturation to describe first-order elimination clearance. The CPB circuit was represented by an additional compartment. We assumed 60 subjects received cefazolin 50 mg.kg-1, with 50 of these subjects undergoing a procedure with CPB. We assumed 15 subjects also received 15 mg.kg-1 vancomycin. Optimal times for up to 8 samples per patient were estimated, ignoring CPB effects, using WinPOPT (University of Otago, New Zealand). Optimal sampling times for determination of CPB related changes were considered separately. Designs were selected based on relative standard errors (RSEs) for model parameters and comparison of criterions summarizing design efficiency. Results: Sample times were 0.001, 0.001, 0.108, 0.36, 1.05, 1.85 h following the first dose, and 0.36 and 2.5 h after the second dose, for With CPB subjects. Sample times were 0.127, 0.43, 0.43, 1.3, 3.18, 6, 6 h after the first dose and 6 h after the second dose, for Without CPB subjects. Five samples, taken directly from the CPB circuit, were required to adequately capture CPB related changes in CPB V and CL. RSE estimates of cefazolin, vancomycin and CPB circuit parameters for the final design were ≤ 30%, with the exception of one of the cefazolin volumes (V2) for which RSEs were 49%. Conclusion: The sampling schedule may be used in the planning of a clinical study of children receiving cefazolin and vancomycin during CPB.

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  • Use of Accelerated Laboratory Evaluation by Extended Nurse Prescribers: A tool to improve practice?

    Cameron, Marie (2007-11-08)

    Conference poster
    The University of Auckland Library

    Bacground – Because of the link between inappropriate antibiotic prescribing and antibiotic resistance, several strategies have been implemented to decrease inappropriate prescribing and improve prescribing practices. As 80% of antibiotic prescribing takes place in primary care, this area has often been the focus of these attempts. An example of such a strategy is the Accelerated Bacteriological Laboratory Evaluation (ABLE) service in Grampian, which provides an overnight microbiology results service. Aim - To describe the knowledge and use of the Accelerated Bacteriological Laboratory Evaluation (ABLE) service by Extended Nurse Prescribers in Grampian (UK). Methodology – Quantitative - Anonymous, self-completed, postal questionnaire of all regional Extended Nurse Prescribers, informed by a preliminary content-setting focus group. Analysis – Descriptive statistics (thematic analysis of focus group). Key Findings – Response rate was 74% (35/47) and 57% (20) of respondents were practice nurses. Eighty nine percent (31) of respondents knew about the ABLE service, and 88% (30) had used it, with 73% (22) using it often. Over half of respondents (55%) stated that they had insufficient information to allow them to make best use of the service. The main barrier to ABLE use was difficulty accessing results (50%/6). The main motivator for ABLE use was the desire to prescribe the correct antibiotic (71%/17). Conclusions – Although the majority of respondents were aware of the ABLE service and have used it, more information at more regular intervals is needed to encourage maximal use. Respondents were more likely to use the service for some conditions than others. Inclusion of information about ABLE in the Extended Nurse Prescribing course followed by regular postal and/or electronic reminders/updates would be preferred. These changes and the expansion of accelerated laboratory evaluation nationwide may help to reduce and improve prescribing practices.

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  • Functional analysis of the novel melanoma master-regulators

    Wang, Li (2008)

    Conference poster
    The University of Auckland Library

    Melanoma is a devastating form of cancer that is especially common in New Zealand and that is incompletely understood. In this project, we are using clinical microarray information about the function of tens of thousands of genes in melanoma patients. We are combining this clinical microarray information with microarray analysis of melanoma cells in the laboratory. In this laboratory analysis we have knocked down the expression of 75 different genes using a method known as siRNA. This clinical and laboratory data is combined mathematically using a method known as gene network analysis. This allows us to identify novel "master-regulators" of melanoma, which are seen as “hubs” in melanoma gene networks. These hubs may drive the uncontrolled growth of melanoma cells, and are likely to be useful as prognostic markers or new drug targets. We have already identified several novel melanoma gene network hubs using this method. The sequences encoding these hubs are cloning into an expression vector, and the candidate hub genes are then screened through a functional screening platform. Since we are interested the clinically important genes, we screen to identify those genes that may play a role in proliferation, sensitivity to drug-induced apoptosis, and survival. We will transfect all the candidate genes (alongside a negative vector only control and a positive control of Bcl-2) into 293T cells (human embryonic kidney cells containing the SV40large T antigen to promote episomal replication of transfected plasmids), and A375 cells (melanoma). We will screen for expressed gene function using assays for viable cell number (MTT), assays for cell cycle progression (flow cytometry), and apoptosis assays. In particular we will use the anti-neoplastic drug etoposide (VP16) to induce apoptosis in cells that have been transfected by these genes and controls, to assess gene product function in modifying the apoptosis induced by VP16. For clinically relevant network hub genes that appear to play a role in controlling proliferation, apoptosis and survival, we will home in further on their mechanism of action (the methods used will depend upon our hypotheses about the gene product's function). We hope some of those hubs may lead to novel diagnostic/prognostic assays and novel drug targets.

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  • Light Exposure Patterns in Children: A Pilot Study

    Backhouse, Simon; Ng, H; Phillips, John (2010-07-27)

    Conference poster
    The University of Auckland Library

    Purpose To examine the light exposure patterns of school aged children in relation to refractive error. Methods School-aged children (13-14 years old, n = 12) were issued with self-contained light meters that recorded the ambient light levels every 10 seconds (HOBO Pendant UA-002-064, Onset Computer Corporation, USA). The ambient light levels were collected every 10 seconds over seven days (one period). Measurements were made in three periods over three consecutive months in winter. Cycloplegic autorefraction and axial length measurements were made at the beginning and end of the three month study. Results Ambient light level recordings indicated that while children spent only a small amount of time outside (10.65 ± 2.52 hours per week, or 5.88 ± 1.39% of the total time; mean ± 95% CI, n = 12) these outdoor periods accounted for a large proportion of their total light exposure (4.72 × 107 ± 1.65 × 107 lux, or 87.95 ± 3.72% of their total light exposure). The subjects were exposed to only 5.72 ± 1.86% of the total available light on average over the measurement period. There was a significant correlation between the amount of time spent indoors (between 10 and 1000 lux) and the cumulative light exposure obtained indoors (R2 = 0.945). There was, however, a poor correlation between the amount of time spent outdoors (>1000 lux) and the cumulative light exposure obtained outdoors (R2 = 0.296). Refractive error was not significantly correlated with cumulative light exposure (R2 < 0.001). There were no significant correlations between the rate of change in light levels and refractive error. Discussion and Conclusions A small amount of time spent outdoors is associated with a large proportion of daily light exposure. While predictable levels of light exposure are obtained indoors, there is a great degree of variability in the amount of light received by going outdoors. Thus, a small amount of extra time spent outdoors can disproportionally affect the total light exposure received per day. Further investigations of the quality (e.g. spectral composition) and quantity (e.g. yearly exposure, differing seasons, etc.) of light received by school-aged children are warranted.

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  • Bridging the Computational Modelling and EHR standards using openEHR and Semantic Web Technology

    Atalag, Koray; Zivaljevic, Aleksandar; Cooling, Michael; Nickerson, David (2015-10-12)

    Conference poster
    The University of Auckland Library

    Linking clinical data to computational physiology will enable real-world model validation as well as the possibility of personalised and population level predictive decision support tools. Electronic health records (EHR) embody quantifiable manifestations of genomic and environmental aspects that impact on biological systems when clinical data are structured. However data quality and semantic interoperability remains a major challenge in the world of EHRs. In the computational physiology domain recent attempts to enable semantic interoperability heavily rely on Semantic Web technologies and utilise ontology-based annotations (e.g. RICORDO) but a wealth of useful information and knowledge sits in EHRs where Semantic Web technologies have very limited use. openEHR provides a set of an open engineering specifications that provides a canonical health record architecture and open source tooling to support data collection and integration. Core openEHR specifications have also been adopted by ISO and CEN making it a full international standard which underpins many national programs and has multi-vendor implementations worldwide. Our work describes how to use openEHR to normalise, annotate and link clinical data with biophysical models by using openEHR Archetypes as semantic pointers to underlying clinical concepts in EHR.

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  • Quality of Life in Fit Elderly Patients with Chronic Lymphocytic Leukemia (CLL) Receiving Oral Fludarabine-Based Regimens As First Line Therapy: Australasian Leukaemia and Lymphoma Group (ALLG) CLL5 Trial

    Suneet, S; Gill, D; Turner, PD; Renwick, WEP; Latimer, M; Mackinlay, N; Berkahn, Leanne; Simpson, DR; Campbell, P; Forsyth, C; Cull, G; Harrup, R; Best, G; Bressel, M; Di Iulio, J; Kuss, BJ; Mulligan, S (2015-12-03)

    Conference poster
    The University of Auckland Library

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  • Gelation of oxidised cereal beta-glucan extracts

    Mohan, Anand (2014-02-21)

    Conference poster
    The University of Auckland Library

    Cereal β-glucan, which occurs in plant cell walls, is the major component of soluble dietary fiber in oat and barley. Soluble fibers with a high solution viscosity, which is positively correlated to molecular weight (MW), lower the serum glucose and cholesterol levels. The relevant health claims on β-glucan as a functional food have been allowed by regulatory authorities, including the EFSA and the US FDA. In most processed-food systems, the native hydrolytic enzymes are inactivated, but oxidative degradation of this non-starch polysaccharide can, however, adversely affect the claimed health benefits. (Kivelä 2011). Although the physiological benefits are positively correlated with the viscosity of β-glucan, the relationship with its gelling capacity is not fully understood. The scope of the Master’s thesis included (1) the study of gelation characteristics of oxidised solutions of oat and barley β-glucan, and (2) correlating the results obtained by dynamic light scattering (DLS) microrheology with conventional rheology.

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  • Lower Limb Estimation from Sparse Landmarks using an Articulated Shape Model

    Zhang, Ju; Hislop-Jambrich, J; Besier, Thor (2016-02-19)

    Conference poster
    The University of Auckland Library

    Rapid generation of lower limb musculoskeletal models is essential for patient-specific gait modeling. Motion-capture is a routine part of gait assessment but contains relatively sparse geometric information. We present an articulated statistical shape model of the lower limb that estimates realistic bone geometry, pose, and muscle attachment regions from seven commonly used motion-capture markers. Our method obtained a lower (p=0.02) surface error of 4.5 mm RMS compared to 8.5 mm RMS using standard isotropic scaling, and was more robust, converging in all 26 test cases compared to 20 for isotropic scaling.

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  • Searching for anomalous light curves in massive data sets

    Rattenbury, Nicholas (2014-01-19)

    Conference poster
    The University of Auckland Library

    The photometric surveys currently under way by the MOA and OGLE collaborations have produced and are extending databases of millions of stellar light curves. These databases have allowed investigations into diverse astrophysical fields including variable stars, proper motion studies and Galactic structure. Odd, or otherwise curious events have been discovered in the databases. We consider here one such event and propose methods for discovering more like it in the microlensing databases. A further aim of this initial work is to set out the prospects of the classification scheme for identifying time series that are maximally discordant - i.e. those that do not look like any other time series in the data set, and which therefore, may be of particular interest.

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  • Novel release method proves successful: The gum leaf skeletoniser parasitoid Cotesia urabae establishes in two new locations

    Gresham, BA; Withers, TM; Avila Olesen, Gonzalo; Berndt, LA (2014-08-12)

    Conference poster
    The University of Auckland Library

    The Australian braconid wasp Cotesia urabae was first released in New Zealand in 2011, as a biological control agent for the gum leaf skeletoniser Uraba lugens (Lepidoptera: Nolidae). The larvae of this moth predominantly attack Eucalyptus spp. (Class: Symphyomyrtus) and, since its predicted future geographic range is extensive, there is concern it could become a serious pest of eucalypt plantations in New Zealand. Initial releases of C. urabae using adult parasitoids were made in Auckland at three separate sites between January and June 2011. Cotesia urabae established at each site and preliminary monitoring has revealed that the wasps have naturally dispersed to six other sites, ranging up to 6 km from an initial release site. In January 2012, C. urabae were released in Whangarei and Tauranga, trialling a novel method using parasitoid-attacked host larvae, rather than adult parasitoids. This method proved to be successful, with establishment now confirmed in both of these locations, and also provided greater flexibility. The two latest releases were made using the same method in Nelson (October 2013) and Napier (February 2014), but it is not yet known if the parasitoid has successfully established in these locations.

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  • Effect of contact lens induced retinal defocus on the thickness of the human choroid

    Chiang, Samuel; Backhouse, S; Phillips, John (2014-04-22)

    Conference poster
    The University of Auckland Library

    PURPOSE The aim of this study was to describe the amplitude and time-course of choroidal thickness changes induced by imposed hyperopic and myopic retinal defocus and to compare the responses in emmetropic and myopic subjects. METHODS Twelve Asian subjects (6 emmetropes and 6 myopes) aged between 18 and 34 years had OCT images of the choroid taken in both eyes at 5 min intervals while exposed to monocular defocus (random right or left eye) for 60 min; the fellow eye was kept optimally corrected (no defocus). Two different monocular defocus conditions (2 D hyperopic or 2 D myopic defocus) were tested on separate occasions. Thickness changes were measured as absolute changes in microns. RESULTS Prior to applying defocus, mean choroidal thickness in myopic eyes (mean ± SD, 256.30µm ± 41.24µm) was significantly less than in emmetropic eyes (mean ± SD, 423.09µm ± 60.69µm) (p<0.05) in 60 minutes. No significant difference was found between emmetropes and myopes in changes of choroidal thickness with the two types of defocus. CONCLUSIONS Small but significant choroidal thickness changes occurred when human eyes were exposed to both myopic and hyperopic monocular defocus. In each case these changes acted to move the retina towards the altered image plane, so as to reduce the degree of defocus. In this small sample we could detect no difference in responses of myopic eyes compared to emmetropic eyes.

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  • An examination of the extent of adult neurogenesis in the carpet shark (Cephaloscyllium isabellum)

    Finger, JSH; Kubke, Maria; Wild, JM; Montgomery, JC (2008)

    Conference poster
    The University of Auckland Library

    Following Altman’s and Kirsche’s challenge to the dogma that no new neurons could be produced during adulthood in the 1960’s, adult neurogenesis was shown in most vertebrate lineages. From a phylogenetic point of view, adult neurogenesis is not an uncommon event, having been demonstrated in reptiles and birds, amphibians, bony fi shes and mammals. At present, however, adult neurogenesis has not been examined in cartilagineous fi shes, the stem line of vertebrates. Sharks are an ideal group in which to study the extent of adult neurogenesis for several reasons: (i) they exhibit continuous body growth throughout life; (ii) in the stingray the number of peripheral axons and neurons continues to increase into adult life; and (iii) in adult gray reef sharks the number of inner ear hair cells also continues to increase. We have begun to evaluate the extent of adult neurogenesis in the carpet shark (Cephaloscyllium isabellum). A specimen of C isabellum was injected i.p. with 230 mg/kg of BrdU, anaesthetised and perfused after 2 hrs. The brain was cryoprotected and cut at 40 μm, and processed following standard immunocytochemical techniques. BrdU was found in a small number of nuclei in close proximity to the ventricular surface, in a similar position than occasional cells labelled with an antibody aginst β-tubuline (III). Some BrdU labelled nuclei were also found throughout the brain that were not stained with our neuronal marker. These preliminary data suggest that adult neurogenesis occurs in sharks and that like in bony fi shes, but unlike birds and mammals, it may also occur in non-telencephalic areas. If widespread adult neurogenesis can be unequivocally demonstrated in sharks, it would indicate that it represents the primitive condition. This therefore raises the question of what modifi cations in brain evolution of modern vertebrate lineages led to the restriction of this ability to specifi c forebrain areas.

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