Search

Resume La simulation dans l’apprentissage de la chirurgie prend une place de plus en plus importante ces dernieres annees et la Haute Autorite de sante a rappele recemment cet objectif ethique prioritaire : « jamais la premiere fois sur le patient ». Des programmes de simulation ont ete valides pour la laparotomie et pour la laparoscopie mais il n’y a pas pour l’instant de programme specifique valide pour la chirurgie robotique. Du fait de l’essor important de cette nouvelle technologie, nous avons developpe a Nancy un programme dedie a l’enseignement hors bloc operatoire de la chirurgie avec le robot Da Vinci. Cet enseignement repose sur l’association d’un enseignement theorique (e-learning) et d’un enseignement pratique en utilisant des simulateurs virtuels (DV-Trainer, Robotic Mentor, DVSS), des simulateurs mecaniques (dome, simulateur abdominal Applied), de la microchirurgie et du wet lab. avec organes d’animaux, animaux anesthesies et cadavres sans oublier le team training. Cet enseignement s’adresse aux chirurgiens en formation avec integration dans la maquette du DES de chirurgie viscerale et digestive et a des chirurgiens diplomes qui peuvent integrer le DIU de robotique general pour acquerir les techniques de base et les DIU specialises (digestif et gynecologique) pour des utilisations du robot dans leur specialite. Ces cursus bases sur le concept du step by step et de la verification des competences permettent un passage a l’activite clinique en toute securite.

Simulation has become increasingly important in surgical teaching in recent years and the French National Authority for Health (HAS) recently underlined the goal and ethical priority: "never the first time on the patient". Simulation programs have been tested and validated for laparotomy and for laparoscopy, but there is not yet a validated program specific for robotic surgery. Due to substantial advances in this new technology, we have developed a program in Nancy dedicated to outside-the-operating room (OR) teaching of robotic surgery using the Da Vinci robot. This teaching is based on a combined program of theoretical teaching (e-learning) and learning of practical skills using virtual simulators (DV-Trainer®, Robotic Mentor®, DVSS®), mechanical simulators (Dome, Applied® abdominal simulators), microsurgery and wet lab using ex vivo animal organs, anesthetized animals, and cadavers. This program also emphasizes team training. The course is intended for residents in surgical training and is integrated into the specialized study diploma (DES) program for Visceral and Digestive Surgery; it also can be used by qualified surgeons who can integrate it with the Inter-University Diploma (DIU) in General Robotic Surgery for basic techniques and also for DIUs in other surgical specialties (digestive and gynecologic surgery) for robotic uses within their specialty. These courses are based on the concept of step-by-step skills acquisition and verification allowing a transition to safe clinical activity.

Objectifs Le nombre croissant de publications mettant en parallele les milieux aeronautiques et medicaux temoigne des similarites dans ces activites. Certains principes utilises en aviation sont certainement extrapolables. Ainsi, la formation sur simulateurs de mirage 2000 etant assuree par des formateurs specialises et non des pilotes, il a paru interessant d’appliquer ce principe de subsidiarite a la formation au competences techniques de base en chirurgie robotique. Methodes De septembre 2015 a mai 2018, la formation en chirurgie robotique a fait appel a des formateurs issus de l’armee de l’air et specifiquement entraines a l’usage des simulateurs de robotique (DV-trainer mimic® ou DVSS intuitive®) ainsi qu’a l’utilisation de la console robot Da Vinci. Les chirurgiens experts/universitaires intervenaient pour le programme pedagogique, la chirurgie sur animal. L’evaluation etait faite par un questionnaire de satisfaction en fin de session (survey monkey). Resultats Vingt et un sessions de formation ont ete evaluees pour un total de 144 chirurgiens. Sur les 5 ateliers qui etaient encadres specifiquement par les formateurs, la pertinence des conseils etait cotee plus de 4/5. Pour l’evaluation globale, le sentiment de progression des stagiaires etait superieur a 4,5/5 de meme que l’impact de la formation sur la qualite du futur travail. A la question « cette formation est-elle a recommander », les reponses etaient a 4,8/5. Conclusion Le principe de subsidiarite (recherche du niveau le plus pertinent et le plus proche pour resoudre des problemes) a montre sa pertinence lors de la formation a la chirurgie robotique en allegeant la tâche des chirurgiens experts/universitaires tout en apportant un haut degre de satisfaction aux chirurgiens stagiaires.

The B30.2 domain is a conserved domain of around 170 amino acids. It is found associated with different protein domains: immunoglobulin domain in the case of butyrophilin and Ring Finger domain in the case of Ret Finger Protein. B30.2 should therefore be considered a migratory domain. We here report new members of these families as well as new protein families having the B30.2 domain, and we tentatively propose a general function for this domain.

This paper presents laboratory investigations of the mechanical behaviour of a typical anisotropic rock: Tournemire shale. Hydrostatic compressibility tests allowed characterization of the structural anisotropy of the material. Triaxial compression tests, including unloading cycles, were performed. Anisotropic elastic response, plastic deformation and failure behaviour have been investigated. The elastic behaviour of the shale is non-linear and the shale exhibits large anisotropic plastic deformation. The failure behaviour of the shale is anisotropic and strongly depends on confining pressure and loading orientation.

The paper deals with a computational investigation on effective moduli of brittle materials weakened by microcracks. The study is based on a suitable adaptation of an indirect boundary element method, namely the displacement discontinuity method. Various aspects of microcracks size and orientation are investigated. For tensile loading (open cracks), the numerical results show good agreement with the classical non-interacting cracks approximation. Comparisons with some not fully random configurations are also presented. When crack-boundary interactions are taken into account, the results agree rather well with the differential approximation, but calculations under compressive loadings are much more complicated because of friction and sliding on crack faces, so an iterative algorithm for sliding and frictional cracks is used. The effective compliance in this case shows very little increase compared with the case of tensile loadings. Comparisons with some theoretical approximations are presented.

The combination of the large effective area and the very low internal background of the ROSAT Position Sensitive Proportional Counter provides an extremely sensitive instrument for the study of diffuse X-ray sources. In this paper we review new results on the X-ray structure of nearby clusters as measured with ROSAT. Substructure is a common feature in these objects. Such structure provides evidence that clusters have formed relatively recently through mergers of relatively large subunits. This behavior is predicted by hierarchical formation theories in a dense universe.

In this paper, we present a numerical study of the massive water injection in petroleum reservoir. A finite element model is developed using a complete coupling algorithm. The thermal convective effect is taken into account. This allows to deal with high fluid flow rate and high temperature variation during the injection time. Evolutions of pore pressure, temperature and rock compaction as function of injection time are studied. A particular objective of this study is to evaluate importances of different terms of thermoporomechanical coupling in this kind of problems. The obtained results show that it is possible to use a semi-decoupled model by eliminating some negligible coupling terms.

A voltage-dependent cationic channel of large conductance is observed in phospholipid bilayers formed by the tip-dip method from proteoliposomes derived from mitochondrial membranes. It is blocked by peptide M, a 13 residue peptide having the properties of a mitochondrial signal sequence. To verify the reliability of the experimental approach, mitochondrial membranes from bovine adrenal cortex or porin-deficient mutant yeast were either fused to planar bilayers or incorporated in giant liposomes which were studied by patch clamp. Cationic channels were found with both techniques. They had the same conductance levels and voltage-dependence as those which have been described using the tip-dip method. Moreover, they were similarly blocked by peptide M. The voltage-dependence of block duration was analyzed in planar bilayer and tip-dip records. Results strengthen the idea that peptide M might cross the channel. Other mitochondrial channels were observed in planar bilayers and patch clamp of giant liposomes. Because they were never detected in tip-dip records, they are likely to be inactivated at the surface monolayer used to form the bilayer in this type of experiment.

An elastoplastic constitutive model is proposed to describe the behavior of porous rock. This model is developed from the concept of two plastic deformation mechanisms and the three-dimensional failure criterion for rock materials previously proposed by Lade. The model is formulated according to experimental observations on a porous chalk. Particular attention is paid to the determination of the material parameters. The validity of the model is examined by comparing its predictions and the experimental results for different trixial tests in drained or undrained conditions.

A new elastoplastic model for porous rocks (chalk) has been developed [1]. It is based on the concept of two plastic deformation mechanisms[2]. In this paper, we present the validation of this model for both homogenous tests and a typical boundary condition problem, hollow cylinder test. Comparisons between experimental results and predictions by the model are presented for each test. Influences of parameter perturbations on numerical simulation are also studied.

We present the revised catalog of galaxy clusters detected as extended X-ray sources in the 160 Square Degree ROSAT Survey, including spectroscopic redshifts and X-ray luminosities for 200 of the 201 members. The median redshift is zmedian=0.25, and the median X-ray luminosity is LX, median=4.2×1043 h-250 ergs s-1 (0.5-2.0 keV). This is the largest high-redshift sample of X-ray-selected clusters published to date. There are 73 objects at z>0.3 and 22 objects at z>0.5 drawn from a statistically complete flux-limited survey with a median object flux of 1.4×10-13 ergs cm-2 s-1. We describe the optical follow-up of these clusters with an emphasis on our spectroscopy, which has yielded 155 cluster redshifts, 110 of which are presented here for the first time. These measurements, combined with 45 from the literature and other sources, provide near-complete spectroscopic coverage for our survey. We discuss the final optical identifications for the extended X-ray sources in the survey region and compare our results to similar X-ray cluster searches.

Here, Joelle Henry and colleagues explore structural and evolutionary relationships between the B7 costimulator molecules and a growing number of molecules encoded within the major histocompatibility complex. They propose that B7 and MHC genes are derived from a common ancestor, with several members of this large gene family possibly having pivotal influences on T-cell activation.

We present the cloning, structural analysis, and mapping of new members belonging to two multigenic families, the B30-RING finger family and the B7.1-B7.2 family, as well as two genes derived by exon shuffling from members of these families. Eight new members were found and three of them map to the human major histocompatibilitiy complex (MHC) region. Phylogenic and physical mapping analysis allowed us to decipher the evolutionary story of these two multigenic families and to shed light on the evolution of the MHC region. We also show that a deductive analysis can be used to predict the existence of a given gene.

New members of the butyrophilin (BT) gene family have been identified by cDNA and genomic cloning. Six genes are described: BT2. 1, 2.2, 2.3, and BT3.1, 3.2, and 3.3. BT2, BT3, and BT form three distinct subfamilies sharing about 95% amino acid identity at the intra subfamily level and 50% identity at the interfamily level. All the BT2 and BT3 subfamily members map close to BT in the juxta-telomeric region of the major histocompatibility complex. The BT2 members have the canonical structural organization of BT, i.e., two immunoglobulin domains followed by a transmembrane anchor and a B30.2 intracytoplasmic domain. In the BT3 subfamily, only BT3.3 has the structural organization of BT. The two other genes, BT3.1 and BT3.2, code for putative protein without the B30.2 domain. In the case of BT3.2, this is due to an Alu insertion in the B30.2 coding exon, leading to a new polyadenylation site.

By searching into Expressed Sequence Tags databases (dbEST) using Blast X algorithm software and a plant phospholipase D as template, we have identified a cDNA from human brain (Z45777) which encodes for a protein similar to the amino acid region 743-929 of the human phospholipase D1 (PLD1), and a cDNA from human liver (R93485) which encodes for a protein similar to region 815-932 of PLD1. Sequence comparison between cloned phospholipases showed the presence of 3 conserved amino acid sequences: AFVGGIDLAYGRWD (box A), IIGSANINDRS (box B), and YIYIENQFFI (box C). Phylogenic analysis indicated that the cDNA from brain and liver encoded for human isologs of PLD1.

The Peptide Sensitive Channel (PSC), a cationic channel of the mitochondrial outer membrane, is blocked by several highly basic peptides. Among these peptides, the most active are pCOX IV (1-12)Y, a mitochondrial addressing peptide and dynorphin B (1-13), a peptide unrelated to mitochondrial physiology. The voltage-dependent characteristics of the block duration of the PSC induced by these peptides and the fact that these peptides are imported into mitochondria in an in vitro assay suggest the involvement of the PSC in peptide translocation into mitochondria. We have analyzed the interaction of Mast Cell Degranulating peptide (MCD), a disulfide rich basic peptide, with yeast and mammalian mitochondria. Electrophysiological experiments with native and reduced forms of this peptide (nMCD and rMCD) showed an interaction of both forms with the yeast PSC. On the other hand, only rMCD blocked the electrical activity of the bovine adrenal cortex PSC. Similarly, although both forms inhibited the import of dynorphin B (1-13) into yeast mitochondria, only rMCD inhibited this import in bovine mitochondria. The correlation between electrophysiological and biochemical data strongly suggest that dynorphin B is translocated across the outer membrane at the level of the PSC.

We have previously shown that a 13-residue basic peptide, derived from the presequence of a mitochondrial precursor, blocked the cationic channel of the outer mitochondrial membrane. The properties of the blockade suggested that the peptide could go through the pore in the presence of a sufficient driving force. In an attempt to evaluate more precisely the relevance of such an interpretation, we have examined the effect on the same channel of basic peptides from 16 to 34 residues, most of which are parts of or derive from mitochondrial presequences. Two peptides were found to induce a reversible voltage-dependent blockade, the properties of which were the same as those of the blockade induced by the 13-residue peptide. The others had a similar effect, but triggered in addition a modification of the voltage gating that persisted after washing the peptide out. The modification was in turn abolished by trypsin added to the side of the channel previously exposed to the peptide. The protease acted on the bound peptide and not on the channel itself. The irreversible modification of the voltage gating, the mechanism of which remains obscure, was not specific for mitochondrial-addressing sequences.

The presence in the mitochondrial outer membrane of a cationic channel blocked by a 13 residue addressing peptide had been shown by the technique of “tip-dip”. This channel was studied in planar bilayers and compared to the anionic porin, the voltage-dependent anion channel, observed in the same conditions. The two activities were clearly different. The peptide sensitive channel, present in both wild type and porin-deficient mutant yeast, is not a rescue channel, but an alternate independent permeability pathway. The channel interacted more strongly with a longer extension of the addressing peptide containing 22 residues, suggesting a physiological interaction of this type of molecule with the cationic channel.

The transfer of spin-labeled and fluorescent lipids between sonicated vesicles and different host membranes has been measured in the presence or absence of a phospholipid transfer protein purified from maize seedlings. It was found that the protein has little specificity towards the phospholipid head group and allows the transfer of hydrophobic long chain phospholipids. By contrast, no transfer of a cholesterol analogue could be detected. By EPR spectroscopy, evidence is presented that shows that the protein catalyzes the incorporation of labeled phospholipids in the outer monolayer of the acceptor membranes. The efficiency of the transfer depends largely on the nature of the acceptor: erythrocytes are more difficult to label than chromaffin granules or liposomes made with unsaturated lipids. Thus, consistent with the high activation energy observed, the transfer is facilitated when it involves fluid membranes. These results are in favor of a process involving the exchange of phospholipids, facilitated by a shuttle protein rather than a fusion mechanism.

Ketanserin is a high affinity ligand of the monoamine transporter of chromaffin granules (KD = 6 nM at 0°C) and of monoaminergic synaptic vesicles. This compound binds to the same site that tetrabenazine and it is an inhibitor of monoamine uptake. 7-Amino-8-iodoketanserin and 7-azido-8-iodoketanserin have been used as iodinated ligands of the transporter, the former for autoradiography of monoaminergic areas on rat brain slices and the latter for photoaffinity labeling of the transporter. The monoamine transporter of bovine chromaffin granules, human pheochromocytoma, rat striatum and rabbit blood platelets are covalently labeled by the second technique. In bovine chromaffin granules, the labeled component is an acidic glycoprotein, with a m.w. of 73000.

*SPE Member Abstract Polyaxial or true triaxial tests have been performed on Polyaxial or true triaxial tests have been performed on weak and strong sandstones in order to investigate the stability, of model boreholes. Both vertical and deviated boreholes in anisotropic stress systems have been studied. The results indicate the decrease in stability of the deviated boreholes with increasing inclination. Boreholes oriented parallel to the maximum horizontal stress direction also produces less stable boreholes compared to those drilled parallel to the minimum horizontal stress. Comparisons of the laboratory test results with simple predictions using linear elasticity, and a Mohr Coulomb failure criterion, show that the boreholes in the strong sandstones are approximately 4 times stronger than predicted; while the weak sandstones are approximately 8 times stronger than predicted. predicted. 1.0 Introduction Increasing use of highly deviated, extended reach and horizontal drilling, has focussed attention on many aspects of drilling, not least on the ability of highly deviated holes to remain open. Associated with this issue, is the potential for hole cleaning problems or the drill packing off, both of which are aggravated by excessive spalling of the wellbore wall. The challenge of minimising such problems, has resulted in the need for more analytical tools, with which to plan the drilling of the boreholes, and assess their feasibility. The analytical and numerical prediction of borehole stability predominantly considers the stresses develsped in a plane perpendicular to the borehole axis, and the comparison of these stresses with the strength of the surrounding material. The comparison of such analyses with laboratory tests, shows an under estimation of the strength of the boreholes by factors of two to four times for competent rocks (Guenot and Santarelli. These conservative predictions are generally attributed to the use of linear elasticity in the analyses and models. Analytical solutions and numerical models incorporating pressure dependent elastic moduli and elasto-plaslicity show less conservatism associated with their predictions of mud weights required to ensure wellbore predictions of mud weights required to ensure wellbore stability. The validation, and the assessment of the accuracy of numerical models and analytical solutions, is of prime importance if these techniques are to be used as predictive tools. Validation of the predictions of these tools predictive tools. Validation of the predictions of these tools would most satisfactorily be performed by comparison with the behaviour and response of drilling a monitored borehole. However, such field validations would not only be expensive, but possibly inconclusive due to difficulties in accurately determining the three in-situ stresses and the in-situ strength and behaviour of the rock, Fleming et al. These latter parameters are of fundamental importance in the input to current analytical and numerical methods. These limitations restrict our present day validation of predictive tools to comparisons present day validation of predictive tools to comparisons with laboratory test results. P. 19

s S41 Eur J Echocardiography Abstracts Supplement, December 2006 MYOCARDIAL VELOCITY IMAGING (DMI) – LV FUNCTION

Abell 963 (z = 0.206) is still the best candidate for a true arc-counterarc lens configuration (Lavery & Henry 1988). A simple model explains the positions, lengths and patchy light distribution of the two arcs. Photometry indicates the arcs also have the same B-R color (Lavery & Henry 1988; Ellis et al. 1991). However, spectroscopic observations have not confirmed that these arcs originate from the same background galaxy. Ellis et al. (1991) detected a single emission line in the spectrum of the smaller northern arc, identifying it as [O II] λ3727 at a redshift of 0.77. Neither Lavery (1989) or Ellis et al. (1991) detected this emission line in the larger southern arc.

Generally, from pressure-time curves obtained in underground hydralulic fracture tests one can determine the breakdown pressure Pc, the fracture reopening pressure Pr and the shut-in pressure Ps. These pressure values are then used for the calculation of the in situ stress state. In this paper we present a method of measurement of the hydraulic fracturing stress in laboratory conditions. First we present the equipment (the true triaxial test apparatus) and the test procedure. The micro-fracturing tests were performed on a 500×500×500 mm granite sample. A straddle packer arrangement was used to pressurize a 52 mm diameter hole. Displacement measurement transducers were mounted within the pressurized test interval to measure fracture width at the wellbore during the fracturing and closure test. Packer pressure, test interval pressure, flow rate and time were recorded. Five complete micro-fracturing tests, for different boundary conditions are presented. Acoustic emission measurements were also performed using transducers located on the block faces. This enables us to evaluate the crack evolution during the tests. Finally, we compare our results with Kirsch solution in a elastic medium obtained for stress around a circular hole.

The dye, oxonol-V (bis(3-phenyl-5-oxoisoxazol-4-yl)pentamethine oxonol), can be used to estimate the transmembrane potential of chromaffin granules. The potentials result either from a resting-state Donnan equilibrium (inside negative at pH 6.6) or from an ATP-driven proton pump. The fluorescence and absorption changes generated by ATP addition depended on the pH of the medium and the dye-to-vesicle ratio. Energization resulted in an increase in the number of oxonol-V binding sites, the new binding sites having the same dissociation constant. The rate of dye association was higher with resting than with energized chromaffin granules. The absorption change was associated with a red shift whereas the fluorescence change involved a quenching due to the increase in dye concentration on the membrane. The absorption and fluorescence changes varied linearly with the transmembrane potential difference when the interior potential was positive relative to the medium.

Experimental curves relating the crack propagation velocity vs the stress intensity factor K 1 were established for a micrograined (1–4 μm) limestone (micrite) and for a fine-grained (100–300 μm) marble. The environment was partly CaCO3 saturated water at 20°C. From these curves V = V ( K 1 ) , it was possible to calculate the relations between stress and time-to-failure and between fracture stress and deformation rate. These calculated relations were verified experimentally by other tests. The correlation appear to be excellent.

Resume Le systeme de transport des catecholamines de la membrane des granules chromaffines a ete solubilise et reconstitue dans des vesicules phospholipidiques. L'activite de ces vesicules implique que la H+-translocase ATP-dependante et le transporteur de la noradrenaline aient ete reconstitues avec succes. La membrane a ete solubilisee par le cholate de sodium en presence d'asolectine et le rapport asolectine/cholate parait critique. L'omission de l'asolectine a pour resultat la reconstitution de vesicules possedant une pompe a protons active mais incapables d'accumuler la noradrenaline. Apres solubilisation des membranes, on a retire le detergent par filtration sur Sephadex G-50 et on a verifie que sa concentration residuelle dans la preparation reconstituee etait inferieure a celle inhibant la pompe a protons des fantomes. La dependance vis-a-vis du pH, le Km pour l'ATP et le Km pour la noradrenaline des vesicules reconstituees sont similaires a ceux des fantomes; leur activite specifique et leur resistance a la reserpine sont variables. L'activite des vesicules est limitee par la reconstitution du transporteur, suggerant que la reconstitution du systeme complet puisse etre utilisee pour le dosage du transporteur. Le transporteur de la noradrenaline n'a pas de lien avec la dopamine β-hydroxylase et ne porte pas de sites de liaison de l'agglutinine de germe de ble.

The subcellular localization of enkephalins was studied in the bovine adrenal medulla. In the adrenal medulla enkephalins (Met-enkephalin, Leu-enkephalin, Met-enkephalin-Arg 6 -Phe 7 and Met-enkephalin-Arg 6 -Gly 7 -Leu 8 ) are found free and in the form of cryptic peptides included in larger precursors. Total Met-enkephalin immunoreactivity, which includes free and cryptic peptides, was determined after a sequential enzymatic treatment with trypsin and carboxypeptidase B. Total Met-enkephalin immunoreactivity, dopamine beta-hydroxylase and catecholamines were found to have a parallel distribution in the various subcellular fractions. The bulk of the total Met-enkephalin immu noreactivity (42%) was recovered in the large granule fraction. The large granule fraction also contained 38% of the total dopamine beta-hydroxylase activity, and 42% of the total catecholamines. Enkephalins are thus concentrated in the chromaffin granules. Chromaffin granules were also separated according to the method of Terland & coworkers 17 into two fractions: one containing the dense noradrenergic vesicles and the other containing lighter adrenergic vesicles. Total Met-enkephalin immunoreactivity was restricted to the fractions containing the lighter adrenergic vesicles. In these fractions the molar ratio of adrenaline to total Met-enkephalin immu noreactivity was 97. This study is in accord with immunocytochemical observations which have indicated that enkephalins are located in adrenergic and not in the noradrenergic cells in the bovine adrenal medulla.

Experimental data were obtained for diffusion of gases at constant total pressure in bidispersed porous alumina solids and monodispersed porous Vycor. The data covered a 1300 1 range of pressures which included the Knudsen and most of the transition region. Previous data covered only a 50 1 range. Experimental diffusivities of the alumina compared closely with those predicted by the Rothfeld effectiveness factor model and the Wakao and Smith random pore model. Data on the Vycor also checked the prediction contrary to the findings of others. A possible explanation may be due to the differences in pore structure. Modified equations were derived to extend the random pore model to special cases for diffusion of gases in porous media.

Two components can be obtained from the luminescent mollusc Pholas dactylus which, when mixed aerobically, produce light. Purification of the substrate luciferin is described. This component is a protein (mol. wt. 50000); absorption and fluorescence spectra are given. The kinetics of the reaction leading to light emission were studied. A biphasic reaction could be induced by incubation of luciferin-luciferase in the absence of O 2 or by incubation at pH 4.8 at o°. Injection of reduced flavin mononucleotide resulted in a flash if injected during the reaction but not after. Among metal ions, only Fe 2+ showed a strong stimulation.

Light could be obtained by the addition of Fe 2+ to purified luciferin from Pholas dactylus in the absence of luciferase. The total light emitted was proportional to the concentration of luciferin used. The characteristics of this nonenzymic emission correspond to those of the fast reaction previously described. It may have a physiological importance since iron is present in the luciferin. The injection of Fe 2+ alone was not sufficient; the presence of a complexing agent such as phosphate or CN − or EDTA was also necessary. Light emission could also be obtained by the addition of H 2 O 2 , in the presence of Fe 2+ , to luciferin. It has been demonstrated that, for a given amount of luciferin, the total light emitted by the action of varying ratios of Fe 2+ and luciferase is constant.

Summary o 1. Evidence is presented that volume is regulated as an independent parameter. Thus, expansion of the blood volume by a small blood transfusion leads to diuresis, its contraction to oliguria. 2. A consideration of the anatomy and physiology of the circulation, including the relative elasticities of the arterial tree and the low-pressure system, suggests the highly distensible great veins and atria as the most appropriate location for “volume” receptors. 3. Negative pressure breathing and oscillation ventilation technics induce diuresis and implicate the thoracic viscera. Further experiments have pinpointed the left atrium as one sensitive area concerned with antidiuretic hormone release. The right atrium appears to be involved in aldosterone secretion. 4. Afferent impulses from the atria travel to the central nervous system by the vagus nerves, entering the medulla by their rostral rootlets. They relay in a restricted area in the region of the vagal sensory nuclei. There is some indirect evidence that they affect aldosterone secretion by impulses relayed to the “midbrain-limbic” region, and antidiuretic hormone secretion by influencing the supraoptic region of the hypothalamus. They may also modify kidney function by changing the brainstem sympathetic nervous outflow. 5. This growing evidence of nervous connections between mechanical events in the heart and the central adjustment of water and mineral excretion promises to throw light on the puzzling metabolic changes in congestive heart failure and a number of other cardiovascular disturbances.

Summary Various methods for the oxidation of Pholas dactylus luciferin with emission of light have been examined. These methods include treatment with ferrous ions and a suitable ligand or with potassium permanganate, and electrochemical oxidation, as well as reaction with the system xanthine - xanthine oxidase - oxygen. Intervention of the superoxide radical ion is postulated as part of the mechanism of light emission from this protein.

Summary Pholad luciferin can be oxidised with emission of light using horse radish peroxidase in place of luciferase. In this reaction, the peroxidase acts as an oxidase and does not require hydrogen peroxide. Conversely, luciferase shows peroxidase activity towards ascorbic acid, but is not thought to be a typical peroxidase. This model reaction has been used to study the mechanism of the Pholas dactylus system. Existence of a prosthetic group in the luciferin has been demonstrated and its modification during light emission is described. The induction of luciferin luminescence by horse radish peroxidase has been compared to other model reactions and it is proposed that the superoxide ion O⨪2 is involved in the formation of an intermediate luciferin peroxide.

The study of the biochemical and physiological functions of the enkephalinergic cell has greatly extended our understanding of peptidergic cells in general. In the adrenal gland, the major part of the proenkephalin-derived peptides is present as intermediates in the processing of the precursor. These peptides are contained within the adrenergic chromaffin granules, from which they are released in response to stimulation of the cell. The nature of the products released depends on the nature of the stimulus, but it appears that mature granules containing completely processed peptides are preferentially released under physiological conditions. In the brain, the presence and release of the heptapeptide that comprises the carboxyl terminus of adrenal proenkephalin suggest that similar mechanisms are operating centrally. The identity of brain and adrenal proenkephalin is further supported by the purification from brain of a large fragment of the proenkephalin molecule, synenkephalin , and the occurrence in brain of this and the other proenkephalin-derived peptides in a molar ratio close to that found in the sequence of the adrenal precursor. The processing of proenkephalin in brain appears to follow the classical models first proposed for peptide hormones (Steiner et al. 1980), which may thus be generalized to include peptide neurotransmitters/neuroregulators. In addition, the results presented in this paper indicate that enkephalins may be cotransmitters in at least two diverse systems. Enkephalins and catecholamines are colocalized in the adrenergic granules of the adrenal gland. In the brain, enkephalins and oxytocin are colocalized in the magnocellular neurons of the hypothalamo-neurohypophyseal oxytocinergic pathway. In both of these systems, the enkephalins are present in a molar concentration that is less than 1% of the concentration of the principal messenger. Such colocalization , coupled with the numerous active peptides that may arise from proenkephalin, suggests many elegant but complex schemes of neurotransmitter interactions. For example, release of enkephalins in the neurohypophysis may regulate oxytocin release through an action on autoreceptors of the oxytocinergic terminal. In the adrenal the coreleased enkephalins may act by regulating presynaptically the cholinergic output of the splanchnic nerve. However, further studies are needed to define clearly the physiological roles of such cotransmission . From the abundance of proenkephalin-derived peptides in the basal ganglia, it appears that enkephalins may represent the principal transmitter in some central neurons.(ABSTRACT TRUNCATED AT 400 WORDS)

Ghosts derived from bovine chromaffin granules have a 32Pi-ATP exchange activity which is associated with the H+ pump of that membrane. This activity was low when compared to bacteria, chloroplasts or submitochondrial particles, but had similar properties (Km for ATP and Pi, ATP/Mg2+ ratio, pH profile, inhibition by dicyclohexylcarbodiimide and tributyltin) to the ATPase from above membranes. The 32Pi-ATP exchange activity was solubilized by cholate/octylglucoside mixtures. The soluble extract was lipid depleted by ammonium sulfate fractionation and partially purified by sucrose gradient centrifugation. The purified preparation was reconstituted with phospholipids by freeze-thawing. The reconstituted vesicles had a 32Pi-ATP exchange sensitive to dicyclohexylcarbodiimide and trybutyltin and an ATPase with a sensitivity to the inhibitors which varied with the reconstitution conditions. The alpha- and beta-subunits of F1-ATPase were major components of the preparation.

The capital intensity and low conversion efficiency of Fischer-Tropsch synthesis makes it noncompetitive with conventional petroleum in the midterm (e.g., 5 to 10 years) under normal economic conditions. However, if crude oil prices rise to higher levels (e.g., $25 to $30/bbl), coal liquefaction processes may prove to be economical. It appears that several other processes under development may become economically attractive before Fischer-Tropsch, although Fischer-Tropsch is the only proven commercially feasible venture at present. The above statement is subject, however, to the successful demonstration and commercialization of these alternative processes. Fischer-Tropsch, as a commercially proven process, may be called upon as a backup should petroleum shortages ensue, world oil prices continue to increase dramatically, and alternate coal liquefaction processes fail to fully develop.

Bovine adrenal medulla tyrosine hydroxylase associates with microtubules during tubulin assembly. Limited proteolytic digestion of tyrosine hydroxylase does not affect the enzymatic activity but prevents its association with tubulin. A possible interpretation is that an ionic interaction occurs between microtubules and a negatively charged region of the enzyme which is removed by the protease treatment. Tyrosine hydroxylase is able to induce purified tubulin assembly as do the microtubule associated proteins; however, the association induced by tyrosine hydroxylase corresponds to the formation of aggregates or organized structures different from microtubules. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and electron microscopy of proteins obtained from bovine adrenal medulla show the presence of tubulin in this tissue.

A solid-phase luminescent immunoassay (LIA), based on the light emission produced as a result of the oxidation of Pholas dactylus luciferin by horseradish peroxidase (HRP) in the presence of molecular oxygen, was developed for human chorionic gonadotropin (hCG). The light emitted in the presence of diethyldithiocarbamate permitted the detection of 0.1 fmol HRP. HRP retained most of its light-emitting capacity after coupling with purified anti-hCG antibody by glutaraldehyde. The LIA involved immobilization of the antigen in plastic tubes coated with purified anti-hCG antibody and detection of the immunocomplex by light emission in the presence of Pholas luciferin. Light emission was linear for antigen concentration within the range 0.5-100 ng/ml. LIA correlates reasonably well with RIA and has a comparable sensitivity (0.5 ng hCG/ml).