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International audience; The breakup of liquid threads into droplets is prevalent in engineering and natural settings. While drop formation in these systems has a long-standing history, existing studies typically consider axisymmetric systems. Conversely, the physics at play when multiple threads are involved and the interaction of a thread with a symmetry breaking boundary remain unexplored. Here, we show that the breakup of closely spaced liquid threads sequentially printed in an immiscible bath locks into crystal-like lattices of droplets. We rationalize the hydrodynamics at the origin of this previously unknown phenomenon. We leverage this knowledge to tune the lattice pattern via the control of injection flow rate and nozzle translation speed, thereby overcoming the limitations in structural versatility typically seen in existing fluid manipulations paradigms. We further demonstrate that these drop crystals have the ability to self-correct and propose a simple mechanism to describe the convergence toward a uniform pattern of drops.

Although the drainage and spreading processes of thin liquid films on substrates have received growing attention during the last decades, the study of three-dimensional cases is limited to a few studies on flat and axisymmetric substrates. In this work, we exploit differential geometry to study the drainage and spreading of thin films on generic curved substrates. We initially investigate the drainage and spreading processes on spheroidal and paraboloidal substrates by employing an asymptotic expansion in the vicinity of the pole and a self-similar approach, finding that the thickness distribution is set by the substrate metric and tangential gravity force components. Spheroids with a large ratio between height and equatorial radius are characterized by a growing thickness moving away from the pole, and vice versa. The non-symmetric coating on a toroidal substrate shows that larger thicknesses and a faster spreading are attained on the inner region than on the outer region of the torus. An ellipsoid with three different axes is chosen as a testing ground for three-dimensional drainage and spreading. Modulations in the drainage solution are observed, with a different variation of the thickness along the two axes. By imposing the conservation of mass, an analytical solution for the average spreading front is obtained. The analytical and numerical results are in good agreement. The resulting drainage solutions show also a good agreement with experimental measurements obtained from the coating of a curing polymer on diverse substrates., 49 pages, 28 figures (including Supporting Information)

Introduction Brachytherapy uses sealed radioactive sources into the tumor. Due to the high dose per fraction and strong gradients in High Dose Rate Brachytherapy (HDR-BT), consequences on dose delivery may be significant if errors occur in the treatment workflow. In order to verify and ensure that the dose is correctly delivered, periodic quality controls (QC) are carried out on machines according to the recommendations of the ESTRO BOOKLET 8. Many tools, complex to use, exist. We therefore developed an quality assurance (QA) tool to check the mandatory machine parameters as well as the dose delivered. Methods Dosilab has developed Securidose, an instrumented phantom using 4 Gallium Nitride (GaN) dosimeters. The phantom can host different inserts targeting afterloader QA and protocol QC up to 2 treatment channels. Specific calculation methods based on GaN dosimeter responses are used to accurately determine the dwell times and dwell positions (Fig. 1). Download : Download high-res image (288KB) Download : Download full-size image We validated the Securidose system software and checked its accuracy with respect to the source dwell position and the measured dose according to the ESTRO guidelines (i.e. 2 mm and 5% respectively). This validation was achieved on 10 measurements with a prescribed dose of 5 Gy and repeated for the 3 inserts. Thereafter we introduced source positioning errors ranging from 1 to 10 mm to test the physical parameter error detectability as well as the impact on the dose. Finally, we developed a 6-channel insert (Fig. 1) to perform quantitative patient-specific QC measurements. Furthermore, measurements have been carried out on HDR-BT phantom to assess the Securidose system repeatability and reproducibility. Results After ten successive measurement runs, we did not observe any significant deviations between the measured and planned source dwell positions and dose, as shown in Table 1. Download : Download high-res image (204KB) Download : Download full-size image As shown on Fig. 2, we observed that the dose deviation exceeding the ESTRO recommendation of 5% are due to dwell deviation greater than 2 mm on the 1-channel insert and 3 mm for the 2 other insert types. Download : Download high-res image (176KB) Download : Download full-size image Conclusion Interests of this phantom are multiple; on the one hand afterloader quality controls can be done quickly and simply: source dwell position and delivered dose can be verified on the same acquisition run. On the other hand, the Securidose-equipped with the 6-channels insert allows quantitative verification of patient-specific treatment plans before treatment for both position and dose.

Introduction Devant une hyperandrogenie, les causes ovariennes, hors syndrome des ovaires polykystiques, sont rares et souvent meconnues par les endocrinologues. Observation Une femme de 60 ans, 3e pare, menopausee, diabetique de type 2, consulte pour un desequilibre glycemique recent motivant l’initiation d’une insulinotherapie. L’examen retrouve des signes d’hyperandrogenie : alopecie ancienne et hirsutisme d’aggravation recente jamais explores. La testosteronemie est elevee a 3463 pg/mL (0–950), avec 17-OH-progesterone legerement augmentee 1,47 ng/mL (menopause 0,08–1,3), DHA-S, Delta-4-androstenedione, axe corticotrope et TSH normaux. Le scanner surrenalien et deux echographies pelviennes sont normaux. L’IRM retrouve des ovaires de taille augmentee, evocateur d’hyperthecose, ainsi qu’une zone nodulaire ovarienne droite. Une annexectomie bilaterale est realisee. L’anatomopathologie retrouve une tumeur steroide a cellules de Leydig de l’ovaire droit, non hilaire, de 7 mm, developpee dans un contexte d’hyperplasie stromale diffuse avec hyperplasie des cellules de Leydig. En post-operatoire a 1 mois, la testosteronemie se normalise (111 pg/mL) avec diminution des besoins en insuline sans regression de l’hyperandrogenie clinique. Discussion Les tumeurs de Leydig et les thecomes, principalement presents a la menopause, sont benins et peuvent etre virilisants. Leur prise en charge est chirurgicale. Il faut savoir y penser meme si les examens complementaires de premiere intention sont normaux. Chez cette patiente, le diagnostic de tumeur de Leydig a ete tardif (retard de consultation, errance diagnostique apres deux echographies ovariennes normales). L’hyperandrogenie induite a ete potentialisee par l’hyperthecose, favorisant le desequilibre de diabete, soit un motif de consultation atypique pour un tel diagnostic.

Resume Introduction et but de l’etude Le but de ce travail etait d’evaluer la cryotherapie en traitement de rattrapage pour une rechute locale apres une curietherapie prostatique. Materiel et methodes Il s’agissait d’une evaluation monocentrique prospective des patients pris en charge par cryotherapie (entre 2013 et 2017) pour une rechute locale (prostate/vesicules seminales) apres une curietherapie prostatique par iode 125 (entre 2000 et 2011). La rechute a ete confirmee par IRM multiparametrique suivie de biopsies ciblees (Koelis). Le caractere local etait affirme par scanographie thoraco-abdopelvienne, scintigraphie osseuse et tomographie par emission de positrons (TEP) a la choline. Le suivi apres la cryotherapie a compris le dosage de la concentration serique d’antigene specifique de la prostate, l’IRM multiparametrique et le toucher rectal a 3 et 12 mois, puis annuellement. La toxicite urinaire et rectale a ete evaluee selon les Common Toxicity Criteria for Adverse Events (CTCAE) V5.0. Resultats et analyse statistique Treize patients ont eu une cryotherapie de rattrapage. La curietherapie avait ete initialement delivree pour une tumeur de stadeT1c-T2a, N0, M0, de score de Gleason 6, une concentration serique mediane d’antigene specifique de la prostate de 7,7 ng/ml (extremes : 4,9–9,1 ng/ml). Le nadir median de la concentration serique d’antigene specifique de la prostate apres la curietherapie etait de 0,6 ng/ml (extremes : 0,1–3,5 ng/ml). Le temps median ecoule avant la rechute etait de 119 mois (extremes : 47–189 mois). La concentration serique mediane d’antigene specifique de la prostate au moment de la rechute etait de 4,1 ng/ml (extremes : 2,4–17,6 ng/ml). L’IRM multiparametrique, la TEP a la choline et les biopsies etaient en faveur d’une rechute locale (lesion unique) dans huit cas. Six d’entre elles sont survenues en dehors de l’isodose de prescription (160 Gy). La cryotherapie a ete associee a une radiotherapie pelvienne chez un patient et a une hormonotherapie adjuvante chez trois (delais : 6 a 12 mois). Avec un suivi median de 20 mois (extremes : 4–63 mois), tous les patients etaient en vie, huit etaient en situation de remission, un de rechute synchrone dans la zone de cryotherapie et en region lomboaortique (hormonotherapie), deux de rechute prostatique controleaterale (nouvelle cryotherapie), un de rechute lomboaortique (radiohormonotherapie) et un de rechute osseuse isolee (radiotherapie stereotaxique). Il a ete observe un cas de toxicite urinaire de grade 1, aucun detoxicite rectale. Conclusion La cryotherapie de rattrapage apres une curietherapie prostatique est bien toleree et assure un taux de controle local satisfaisant au long cours.

The standard of care of local treatment for extremities soft tissue sarcomas relies on conservative surgery combined with external beam radiotherapy. Brachytherapy can be realized instead of external beam radiotherapy in selected cases, or more often used as a boost dose on a limited volume on the area at major risk of relapse, especially if a microscopic positive resection is expected. In these cases, this combination allows to obtain the best local control rates published. Close interaction and communication between radiation oncologist and surgeon are mandatory at the time of implantation to limit the risk of side effects. Long-term results are available for low-dose rate brachytherapy. Nowadays, pulsed dose rate is more often used. More limited experience has been reported for high dose rate.

Resume Les carcinomes cutanes de type basocellulaire ou epidermoide sont des lesions frequentes pour lesquelles le pronostic est essentiellement lie au controle local. La chirurgie reste le traitement de reference, si elle permet une exerese complete sans prejudice esthetique ou fonctionnel. La curietherapie peut constituer une option therapeutique interessante dans les autres situations. Elle est particulierement bien adaptee au traitement des lesions periorificielles de la face. Elle est le plus souvent effectuee a bas debit de dose, mais peut aussi etre realisee a haut debit si un traitement ambulatoire est preferable. Elle permet l’obtention d’un taux eleve de controle local, avec tres peu d’effets secondaires tardifs. Son indication doit etre discutee des la prise en charge initiale, en fonction de l’âge et de l’etat general du patient, des caracteristiques de la lesion et du risque de retentissement esthetique ou fonctionnel des differentes options de traitement.

Landuse changes for the purposes of cultivation often destabilise a substantial part of the initially stabilized organic matter (OM) in surface soils. However, the mechanisms of OM destabilisation are poorly documented, particularly with respect to organomineral complexes. The aim of this study was to characterize and quantify the effects of landuse on various OM pools, while focusing particularly on mineral-bound OM in a ferralsol. Four different parameters were assessed: the proportion of mineral-bound OM, the nature of the minerals (poorly crystalline aluminosilicates, gibbsite, halloysite and iron oxides) contributing to organomineral complexes, landuse, and soil depth (surface horizons versus non-tilled deeper horizons). The study site had a field with C4 vegetation that had been cultivated for 186 years and compared to an uncultivated reference plot with C3 vegetation. Organomineral complexes were separated by densimetric fractionation and characterized by mineralogical and carbon isotopic methods. Depending on the considered horizon, 58 to 80% of the OM was stabilized through organomineral complexation. Chemosorption of organic compounds at the surface of mineral phases was thus found to be a major stabilisation process in the ferralsol. Although cultivation significantly affected OM pools that were not bound to minerals (particulate non-occluded and particulate occluded OM), these pools represented a low proportion (similar to 5%) of the carbon budget variations in the profile. Most variations in carbon stocks within the profile were attributed to organic matter located in organomineral complexes. Several potential processes were highlighted on the organomineral complex scale: (i) cultivation may have modified the physicochemical stability of mineral phases (involving dissolution and/or formation); (ii) cultivation could have led to vertical migration of organomineral complexes and their accumulation deeper in the profile; (iii) cultivation systematically modified the amount of organic compounds linked to minerals, with a decrease in topsoil and an increase in deep soil. In further studies to determine the impact of cultivation on soil carbon stocks, it would thus be interesting to continue assessing mechanisms that control the dynamics of mineral-bound OM while also investigating soil layers to a depth of at least 1 m. (C) 2009 Elsevier B.V. All rights reserved.

Many cells and organisms are rendered transiently resistant to lethal heat shock by short exposure to sublethal temperatures. This induced thermotolerance is thought to be related to increased amounts of heat shock proteins (HSPs) which, as molecular chaperones, protect cells from stress-induced damage. As part of a study on bivalve stress and thermotolerance, work was undertaken to examine the effects of sublethal heat shock on stress tolerance of juveniles of the northern bay scallop, Argopecten irradians irradians, in association with changes in the levels of cytoplasmic HSP70 and 40. Juvenile bay scallops heat-shocked at a sublethal temperature of 32 °C survived an otherwise lethal heat treatment at 35 °C for at least 7 days. As determined by ELISA, acquisition of induced thermotolerance closely paralleled HSP70 accumulation, whereas HSP40 accrual appeared less closely associated with thermotolerance. Quantification of scallop HSPs following lethal heat treatment, with or without conditioning, suggested a causal role for HSP70 in stress tolerance, with HSP40 contributing to a lesser, but significant extent. Overall, this study demonstrated that sublethal heat shock promotes survival of A. irradians irradians juveniles upon thermal stress and the results support the hypothesis that HSPs have a role in this induced thermotolerance. Exploitation of the induced thermotolerance response shows promise as a means to improve survival of bay scallops in commercial culture.

The effects of thermal stress on the induction of heat shock proteins (HSPs) were examined in northern bay scallops, Argopecten irradians irradians, a relatively heat tolerant estuarine species, and sea scallops, Placopecten magellanicus, a species residing in cooler, deeper water. Polyclonal antibodies used in this work for analysis of inducible HSP70 and HSP40 only recognized proteins of 72 and 40 kDa respectively from the mantles of both scallop species. Additionally, HSP quantification using the antibody to HSP70 was equally effective by either immunoprobing of western blots or ELISA, demonstrating that either approach could be successfully employed for analysis of thermal response in scallops. Sea scallop HSP70 and HSP40 did not change when animals were heat-shocked for 3 h by raising the temperature from 10 °C to 20 °C; however, a 24 h treatment of the same magnitude elicited a significant response. Conversely, bay scallops displayed rapid and prolonged HSP70 and HSP40 responses during the recovery period following a 3 h heat shock from 20 °C to 30 °C. Temperature reduction from 20 °C to 3 °C for 3 h also caused significant HSP70 and HSP40 increases in bay scallops; this represents the first time cold shock was shown to induce HSP synthesis in bivalve mollusks. The onset of the HSP40 response was more rapid than for HSP70, occurring at the end of the cold shock itself prior to transfer to a recovery temperature. Both proteins responded maximally during recovery at control temperature. HSP responses of sea and bay scallops to thermal stress may be related to their habitat in the natural environment and they suggest a differential capacity for adaptation to temperature change. This is an important consideration in assessing the response of these scallops to different culture conditions.

Aims/hypothesis: Effects of the transcription factor v-maf musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA) on the regulation of beta cell gene expression and function were investigated. Materials and methods: INS-1 stable cell lines permitting inducible up- or downregulation of this transcription factor were established. Results: MAFA overproduction enhanced and its dominant-negative mutant (DN-MAFA) diminished binding of the factor to the insulin promoter, correlating with insulin mRNA levels and cellular protein content. Glucose-stimulated insulin secretion was facilitated by MAFA and blunted by DN-MAFA. This is partly due to alterations in glucokinase production, the glucose sensor of beta cells. In addition, the expression of important beta cell genes, e.g. those encoding solute carrier family 2 (facilitated glucose transporter), member 2 (formerly known as GLUT2), pancreatic and duodenal homeobox factor 1 (PDX1), NK6 transcription factor-related, locus 1 (NKX6-1), glucagon-like peptide 1 receptor (GLP1R), prohormone convertase 1/3 (PCSK1) and pyruvate carboxylase (PC), was regulated positively by MAFA and negatively by DN-MAFA. Conclusions/interpretation: The data suggest that MAFA is not only a key activator of insulin transcription, but also a master regulator of genes implicated in maintaining beta cell function, in particular metabolism-secretion coupling, proinsulin processing and GLP1R signalling. Our in vitro study provides molecular targets that explain the phenotype of recently reported Mafa-null mice. We also demonstrate that MAFA is produced specifically in beta cells of human islets. Glucose influenced DNA-binding activity of MAFA in rat islets in a bell-shaped manner. MAFA thus qualifies as a master regulator of beta-cell-specific gene expression and function

Objectifs Les strategies de traitements d’un cancer de la prostate sont multiples et, pour les tumeurs de bas risque, la curietherapie focale est une option therapeutique proposee en alternative a la surveillance active. Ce traitement focal reste aujourd’hui en cours d’evaluation car trois questions sont imparfaitement resolues : comment definir avec precision la zone a traiter, comment focaliser l’agent therapeutique sur cette cible et enfin comment surveiller en toute securite le reste de la glande apres traitement ? Dans le cadre du projet de curietherapie focale mene a l’institut universitaire du cancer de Toulouse, deux volets sont presentes : l’apport du recalage multimodalites et l’impact sur la faisabilite dosimetrique. Patients et methodes La realisation des curietherapies focales de prostate a l’institut universitaire du cancer de Toulouse se fait a l’aide d’une fusion de l’IRM/et de l’echographie avec Koelis. En regard de la biopsie positive, un grain ancillaire est implante dans le foyer tumoral. La dosimetrie est ensuite realisee avec Variseed, la prescription est de 160 Gy dans le volume cible previsionnel et la technique Quicklink est utilisee pour implanter les grains radioactifs. Des fusions rigide et non-rigide ont ete effectuees chez les neuf premiers patients en utilisant trois solutions logicielle : Variseed, Slicer 3D et Mirada. Les fusions ont ete approuvees qualitativement par un radiologue et une analyse quantitative a ete realisee en calculant les normes des vecteurs de deplacement de quatre points d’interet. Resultats Pour les neuf premiers patients, l’evaluation des resultats du recalage etait en moyenne de 1,88 mm (0,35–2,5) pour Variseed, 0,58 mm (0,14–1,02) pour Slicer et 0,32 mm (0,13–0,55) pour Mirada. Conclusions La definition du volume cible est primordiale en curietherapie focale, d’autant plus si seul le foyer tumoral dont la biopsie est positive est traite. Les procedures de recalage testees a l’institut universitaire du cancer de Toulouse confirment la necessite d’une fusion d’image optimale afin de delineer nos volumes sur les differentes modalites. De plus, l’evaluation dosimetrique sur ces recalages permettra de voir l’impact des deformations dans les forts gradients de dose.

Previous studies in rat islets have suggested that anaplerosis plays an important role in the regulation of pancreatic beta cell function and growth. However, the relative contribution of islet beta cells versus non-beta cells to glucose-regulated anaplerosis is not known. Furthermore, the fate of glucose carbon entering the Krebs cycle of islet cells remains to be determined. The present study has examined the anaplerosis of glucose carbon in purified rat beta cells using specific 14C-labeled glucose tracers. Between 5 and 20 mM glucose, the oxidative production of CO2 from [3,4-14C]glucose represented close to 100% of the total glucose utilization by the cells. Anaplerosis, quantified as the difference between 14CO2 production from [3,4-14C]glucose and [6-14C]glucose, was strongly influenced by glucose, particularly between 5 and 10 mM. The dose dependence of glucose-induced insulin secretion correlated with the accumulation of citrate and malate in beta(INS-1) cells. All glucose carbon that was not oxidized to CO2 was recovered from the cells after extraction in trichloroacetic acid. This indirectly indicates that lactate output is minimal in beta cells. From the effect of cycloheximide upon the incorporation of 14C-glucose into the acid-precipitable fraction, it could be calculated that 25% of glucose carbon entering the Krebs cycle via anaplerosis is channeled into protein synthesis. In contrast, non-beta cells (approximately 80% glucagon-producing alpha cells) exhibited rates of glucose oxidation that were (1)/(3) to (1)/(6) those of the total glucose utilization and no detectable anaplerosis from glucose carbon. This difference between the two cell types was associated with a 7-fold higher expression of the anaplerotic enzyme pyruvate carboxylase in beta cells, as well as a 4-fold lower ratio of lactate dehydrogenase to FAD-linked glycerol phosphate dehydrogenase in beta cells versus alpha cells. Finally, glucose caused a dose-dependent suppression of the activity of the pentose phosphate pathway in beta cells. In conclusion, rat beta cells metabolize glucose essentially via aerobic glycolysis, whereas glycolysis in alpha cells is largely anaerobic. The results support the view that anaplerosis is an essential pathway implicated in beta cell activation by glucose.

Cutaneous basal or squamous cell carcinomas are frequent lesions, their prognosis being associated to local control. Surgery remains the standard of treatment, if a complete resection can be realized without impairment of cosmesis or function. Brachytherapy can be used in the other cases, and is especially well adapted to periorificial lesions of the face. It is mostly realized with low dose rate iridium wires, but can be done with high dose rate if outpatient treatment is preferred. It allows high local control rates with very few late complications. The indication has to be discussed as first line treatment, according to the patient's age and general condition, the characteristics of the lesion, and the risk of late cosmetic or functional side-effects of the different therapeutic options.

The energy and specific energy absorbed in the main cell compartments (nucleus and cytoplasm) in typical radiobiology experiments are usually estimated by calculations as they are not accessible for a direct measurement. In most of the work, the cell geometry is modelled using the combination of simple mathematical volumes. We propose a method based on high resolution confocal imaging and ion beam analysis (IBA) in order to import realistic cell nuclei geometries in Monte-Carlo simulations and thus take into account the variety of different geometries encountered in a typical cell population. Seventy-six cell nuclei have been imaged using confocal microscopy and their chemical composition has been measured using IBA. A cellular phantom was created from these data using the ImageJ image analysis software and imported in the Geant4 Monte-Carlo simulation toolkit. Total energy and specific energy distributions in the 76 cell nuclei have been calculated for two types of irradiation protocols: a 3 MeV alpha particle microbeam used for targeted irradiation and a 239Pu alpha source used for large angle random irradiation. Qualitative images of the energy deposited along the particle tracks have been produced and show good agreement with images of DNA double strand break signalling proteins obtained experimentally. The methodology presented in this paper provides microdosimetric quantities calculated from realistic cellular volumes. It is based on open-source oriented software that is publicly available.

Introduction Treatment of chestwall with lymph nodes (internal mammary and clavicular nodes) is achieved in most of the centers with conventional radiotherapy using photons and electrons beams with junctions. The aim of this study is to do a dosimetric comparative study between two technics using modulation irradiation: Tomotherapy and Rapid Arc (RA). Material and methods Seven patients (5 left, 2 right) were treated using Tomotherapy. For these patients a RA plan was prepared retrospectively. Patients were positioned supine with two arms above the head. The prescribed dose was 50 Gy for the chestwall and 46–50 Gy for the lymph nodes. Optimisation constraints were increased until the PTV coverage was acceptable. Tomotherapy plans were computed with a 2.5–5 cm collimation and a 0.287 pitch. RA plans were computed using a 5 mmbolus on the chestwall, 2 arcs (60–180°) and a +/-10° collimator rotation. Doses delivered to targets, heart and both lungs are reported. Results For the 7 patients the heart mean dose was 7.1–8.6 Gy (mean 7.5 Gy) with Tomotherapy and 4.4–18.1 Gy (mean 9.9 Gy) for RA. For the ipsilateral lung, the mean dose, V5, V20 and V30 were respectively 10.1–14.7 Gy, 56.4–85.7%, 14.8–25.9% and 6.2–16.6% for Tomotherapy. For RA, these values were 10.5–16.0 Gy, 65.3–96.0%, 14.8–30.0% and 6.2–16.6%. Conclusion For 5/7 patients RA plans were acceptable but the OAR doses were generally higher than Tomotherapy plans (in particular V5 of lungs and lung mean dose). For 2/7 patients (left side) RA plans were not acceptable.

A combined PET/CT tomograph with the unique capability to acquire accurately aligned functional and anatomical images for any part of the human body has been designed and built. The PET/CT, or SMART scanner, was developed by combining a Siemens Somatom AR.SP spiral CT scanner with a partial ring rotating ECAT ART PET tomograph. All components are mounted on a common rotational support within a single gantry that has an axial depth of 110 cm. The PET and CT components can be operated either separately or in combined mode. In combined mode, the CT images are used to correct the PET data for scatter and attenuation. Fully quantitative whole-body images can be obtained for an axial extent of up to 100 cm in an imaging time of less than one hour. When operated in PET mode alone, transmission scans are acquired with two 15 mCi cesium sources. We report the first performance measurements from the scanner, and present some illustrative clinical studies.

The authors have implemented dual multi-slit collimator singles transmission sources on the ECAT ART comprising two sets of 12 slits having an axial pitch of twice the axial crystal ring pitch. The slits illuminating opposing detector banks are interleaved, achieving full coverage of all crystal rings as two /sup 137/Cs point sources are simultaneously rastered axially behind the collimators. Transmission data are normalized to a slab phantom scan and corrected for scatter and cross section variation using a log-linear transformation of the attenuation factors. The value of the linear attenuation coefficient in water phantoms has been measured as 0.0946/spl plusmn/0.0044 cm/sup -1/ for 2 min scans employing two 6 mCi sources. A quasi-simultaneous mock scan capability permits direct acquisition and subtraction of the emission background in post-injection transmission acquisitions.

Urastoma cyprinae occurs on the gills of various bivalves species, including the eastern oyster Crassostrea virginica. While the worm is known to cause severe gill disruption in mussels, no evidence of this nature has been described for oysters. Nonetheless, high levels of U. cyprinae have been reported in oysters, which may, in turn, reduce the oyster's overall condition. U. cyprinae is strongly attracted to oyster gill mucus, which is suggested to play an active role in the worm's feeding activities. Furthermore, host mucus contains many active components, including proteases, which have been suggested to play a defensive role against invading organisms. It follows, therefore, that some of the interactions between U. cyprinae and oysters take place in host gill mucus. Studies were undertaken to determine whether the presence of U. cyprinae altered the electrophoretic profiles of oyster gill mucus, using proteases as indicators. Findings reveal that oyster gill mucus contains three proteases, a putative acid protease at 96 kDa, a zinc metalloprotease at 64 kDa, and a serine protease at 33 kDa. Results based on experiments using mucus preparations extracted from infected and noninfected oysters, along with those using lyophilized mucus incubated with live U. cyprinae, confirm that the presence of U. cyprinae alters the protease composition of gill mucus. The present data demonstrate that both U. cyprinae and host gill mucus actively secrete proteases. While the precise roles of these enzymes still need to be defined, one of their functions may be associated with digestion-related activities induced by the worm.

Topics addressed by this working group are: (1) immediate needs of the cold-moderator community and how to fill them; (2) synthetic scattering kernels; (3) very simple synthetic scattering functions; (4) measurements of interest; and (5) general issues. Brief summaries are given for each of these topics.

Previous studies in rat islets have suggested that anaplerosis plays an important role in the regulation of pancreatic beta cell function and growth. However, the relative contribution of islet beta cells versus non-beta cells to glucose-regulated anaplerosis is not known. Furthermore, the fate of glucose carbon entering the Krebs cycle of islet cells remains to be determined. The present study has examined the anaplerosis of glucose carbon in purified rat beta cells using specific 14C-labeled glucose tracers. Between 5 and 20 mM glucose, the oxidative production of CO2 from [3,4-14C]glucose represented close to 100% of the total glucose utilization by the cells. Anaplerosis, quantified as the difference between 14CO2 production from [3,4-14C]glucose and [6-14C]glucose, was strongly influenced by glucose, particularly between 5 and 10 mM. The dose dependence of glucose-induced insulin secretion correlated with the accumulation of citrate and malate in beta(INS-1) cells. All glucose carbon that was not oxidized to CO2 was recovered from the cells after extraction in trichloroacetic acid. This indirectly indicates that lactate output is minimal in beta cells. From the effect of cycloheximide upon the incorporation of 14C-glucose into the acid-precipitable fraction, it could be calculated that 25% of glucose carbon entering the Krebs cycle via anaplerosis is channeled into protein synthesis. In contrast, non-beta cells (approximately 80% glucagon-producing alpha cells) exhibited rates of glucose oxidation that were (1)/(3) to (1)/(6) those of the total glucose utilization and no detectable anaplerosis from glucose carbon. This difference between the two cell types was associated with a 7-fold higher expression of the anaplerotic enzyme pyruvate carboxylase in beta cells, as well as a 4-fold lower ratio of lactate dehydrogenase to FAD-linked glycerol phosphate dehydrogenase in beta cells versus alpha cells. Finally, glucose caused a dose-dependent suppression of the activity of the pentose phosphate pathway in beta cells. In conclusion, rat beta cells metabolize glucose essentially via aerobic glycolysis, whereas glycolysis in alpha cells is largely anaerobic. The results support the view that anaplerosis is an essential pathway implicated in beta cell activation by glucose.